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Sample records for laser morphological sem

  1. Effect of Laser Treatment on Surface Morphology of Indirect Composite Resin: Scanning Electron Microscope (SEM) Evaluation

    OpenAIRE

    Mirzaie, Mansore; Garshasbzadeh, Nazanin Zeinab; Yassini, Esmaeil; Shahabi, Sima; Chiniforush, Nasim

    2013-01-01

    Introduction: The aim of this study was to evaluate and compare the Scanning electron microscope (SEM) of indirect composite conditioned by Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser, Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) laser and Carbon Dioxide (CO2) laser.

  2. Effect of Laser Treatment on Surface Morphology of Indirect Composite Resin: Scanning Electron Microscope (SEM) Evaluation.

    Science.gov (United States)

    Mirzaie, Mansore; Garshasbzadeh, Nazanin Zeinab; Yassini, Esmaeil; Shahabi, Sima; Chiniforush, Nasim

    2013-01-01

    The aim of this study was to evaluate and compare the Scanning electron microscope (SEM) of indirect composite conditioned by Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser, Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) laser and Carbon Dioxide (CO2) laser. 18 indirect composite blocks (GC Gradia DA2, Japan) with 15 × 10 × 10 mm dimensions were made. The bonding surface of these blocks were polished, then the samples were divided into six groups as follow: Er:YAG laser with output power of 0.5 W and frequency of 10 Hz, Nd:YAG laser with output power of 0.25, 0.5 W and frequency of 10 Hz, CO2 laser with output power of 0.5 W and frequency of 10 Hz and 5 Hz, and no treatment. Then, the surfaces were evaluated by SEM. Irregularities were observed in Er:YAG laser samples compared to control group that produced suitable retention for adhesion of cements. Nd:YAG and CO2 lasers showed melting areas. Among different lasers, Er:YAG laser can be used as an alternative technique for surface treatment of indirect composites.

  3. SEM evaluation of the morphological changes in hard dental tissues prepared by Er: YAG laser and rotary instruments

    Directory of Open Access Journals (Sweden)

    Tomov Georgi

    2010-09-01

    Full Text Available Effective ablation of dental hard tissues by means of the erbium:yttrium-aluminum garnet (Er: YAG laser has been reported recently, and its application to caries removal and cavity preparation has been expected. However, few studies have investigated the morphological changes in hard dental tissues after Er: YAG laser caries treatment. In the present study the morphological changes in hard dental tissues after Er: YAG laser caries ablation in vitro was compared with that of conventional mechanical treatment. Thirty extracted human teeth with caries were used. Ten tooth was treated with the Er: YAG laser, and the other was treated with a conventional steel and diamond burs. Laser treatment was performed by means of a non-contact irradiation modes with cooling water spray, with a new Er: YAG laser (LiteTouch. Conventional bur treatment was conducted by means of a low-speed micromotor and air turbine with water cooling. Scanning electron microscope (SEM observations were performed for each treatment. The Er: YAG laser ablated carious dentin effectively with minimal thermal damage to the surrounding intact dentin, and removed infected and softened carious dentin to the same degree as the burtreatment. In addition, a lower degree of vibration was noted with the Er: YAG laser treatment. The SEM examination revealed characteristic micro-irregularities of the lased dentin and enamel surfaces with potential benefits for adhesive restorations. Our results show that the Er: YAG laser is promising as a new technical modality for caries treatment

  4. Effect of instrumentation using curettes, piezoelectric ultrasonic scaler and er,cr:Ysgg laser on the morphology and adhesion of blood components on root surfaces - A SEM study

    OpenAIRE

    Tsurumaki, Jackeline do Nascimento [UNESP; Souto,Bráulio Henrique Marques; de Oliveira, Guilherme José Pimentel Lopes; Sampaio, José Eduardo Cezar [UNESP; Marcantonio Júnior, Elcio [UNESP; Marcantonio, Rosemary Adriana Chierici [UNESP

    2011-01-01

    This study used scanning electron microscopy (SEM) to evaluate the morphology and adhesion of blood components on root surfaces instrumented by curettes, piezoelectric ultrasonic scaler and Er,Cr:YSGG laser. One hundred samples from 25 teeth were divided into 5 groups: 1) Curettes; 2) Piezoelectric ultrasonic scaler; 3) Curettes plus piezoelectric ultrasonic scaler; 4) Er,Cr:YSGG laser; 5) Curettes plus Er,Cr:YSGG laser. Ten samples from each group were used for analysis of root morphology an...

  5. Shear bond strength and SEM morphology evaluation of different dental adhesives to enamel prepared with ER:YAG laser

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    Patrícia T Pires

    2013-01-01

    Full Text Available Context: Early observations of enamel surfaces prepared by erbium lasers motivated clinicians to use laser as an alternative to chemical etching. Aims: Evaluate shear bond strength (SBS values of different dental adhesives on Erbium:Yttrium Aluminum Garnet (Er:YAG laser prepared enamel and to evaluate possible etching patterns correlations between dental adhesives and SBS values. Subjects and Methods: One hundred bovine incisors were randomly assigned to SBS tests on enamel (n = 15 and to enamel morphology analysis ( n = 5 after Er:YAG laser preparation as follows: Group I - 37% phosphoric acid (PA+ ExciTE® ; Group II - ExciTE® ; Group III - AdheSE® self-etching; Group IV - FuturaBond® no-rinse. NR; Group V - Xeno® V. Teeth were treated with the adhesive systems and subjected to thermal cycling. SBS were performed in a universal testing machine at 5 mm/min. Statistical Analysis Used: One-way ANOVA and post-hoc tests (p < 0.05. For the morphology evaluation, specimens were immersed in Ethylenediamine tetraacetic acid (EDTA and the etching pattern analyzed under Scanning Electron Microscope (SEM. Results: Mean bond strengths were Group I - 47.17 ± 1.61 MPa (type I etching pattern; Group II - 32.56 ± 1.64 MPa, Group III - 29.10 ± 1.34 MPa, Group IV - 23.32 ± 1.53 MPa (type III etching pattern; Group V - 24.43 MPa ± 1.55 (type II etching pattern. Conclusions: Different adhesive systems yielded significantly different SBSs. Acid etching significantly increased the adhesion in laser treated enamel. No differences in SBS values were obtained between AdheSE® and ExciTE® without condition with PA. FuturaBond® NR and Xeno® V showed similar SBS, which was lower in comparison to the others adhesives. No correlation between enamel surface morphology and SBS values was observed, except when PA was used.

  6. Shear bond strength and SEM morphology evaluation of different dental adhesives to enamel prepared with ER:YAG laser.

    Science.gov (United States)

    Pires, Patrícia T; Ferreira, João C; Oliveira, Sofia A; Azevedo, Alvaro F; Dias, Walter R; Melo, Paulo R

    2013-01-01

    Early observations of enamel surfaces prepared by erbium lasers motivated clinicians to use laser as an alternative to chemical etching. Evaluate shear bond strength (SBS) values of different dental adhesives on Erbium:Yttrium Aluminum Garnet (Er:YAG) laser prepared enamel and to evaluate possible etching patterns correlations between dental adhesives and SBS values. One hundred bovine incisors were randomly assigned to SBS tests on enamel (n = 15) and to enamel morphology analysis (n = 5) after Er:YAG laser preparation as follows: Group I - 37% phosphoric acid (PA)+ ExciTE(®); Group II - ExciTE(®); Group III - AdheSE(®) self-etching; Group IV - FuturaBond(®) no-rinse. NR; Group V - Xeno(®) V. Teeth were treated with the adhesive systems and subjected to thermal cycling. SBS were performed in a universal testing machine at 5 mm/min. One-way ANOVA and post-hoc tests (P adhesive systems yielded significantly different SBSs. Acid etching significantly increased the adhesion in laser treated enamel. No differences in SBS values were obtained between AdheSE(®) and ExciTE(®) without condition with PA. FuturaBond(®) NR and Xeno(®) V showed similar SBS, which was lower in comparison to the others adhesives. No correlation between enamel surface morphology and SBS values was observed, except when PA was used.

  7. Wavelength dependent laser-induced etching of Cr–O doped GaAs: Morphology studies by SEM and AFM

    Indian Academy of Sciences (India)

    B Joshi; S S Islam; H S Mavi; Vinita Kumari; T Islam; A K Shukla; Harsh

    2009-02-01

    The laser induced etching of semi-insulating GaAs $\\langle$100$\\rangle$ is carried out to create porous structure under super- and sub-bandgap photon illumination (ℎν). The etching mechanism is different for these separate illuminations where defect states play the key role in making distinction between these two processes. Separate models are proposed for both the cases to explain the etching efficiency. It is observed that under sub-bandgap photon illumination the etching process starts vigorously through the mediation of intermediate defect states. The defect states initiate the pits formation and subsequently pore propagation occurs due to asymmetric electric field in the pore. Formation of GaAs nanostructures is observed using scanning electron (SEM) and atomic force microscopy (AFM).

  8. Effect of instrumentation using curettes, piezoelectric ultrasonic scaler and Er,Cr:YSGG laser on the morphology and adhesion of blood components on root surfaces: a SEM study.

    Science.gov (United States)

    Tsurumaki, Jackeline do Nascimento; Souto, Bráulio Henrique Marques; Oliveira, Guilherme José Pimentel Lopes de; Sampaio, José Eduardo Cézar; Marcantonio Júnior, Elcio; Marcantonio, Rosemary Adriana Chiérici

    2011-01-01

    This study used scanning electron microscopy (SEM) to evaluate the morphology and adhesion of blood components on root surfaces instrumented by curettes, piezoelectric ultrasonic scaler and Er,Cr:YSGG laser. One hundred samples from 25 teeth were divided into 5 groups: 1) Curettes; 2) Piezoelectric ultrasonic scaler; 3) Curettes plus piezoelectric ultrasonic scaler; 4) Er,Cr:YSGG laser; 5) Curettes plus Er,Cr:YSGG laser. Ten samples from each group were used for analysis of root morphology and the other 10 were used for analysis of adhesion of blood components on root surface. The results were analyzed statistically by the Kruskall-Wallis and Mann-Whitney tests with a significance level of 5%. The group treated with curettes showed smoother surfaces when compared to the groups were instrumented with piezoelectric ultrasonic scaler and the Er,Cr:YSGG laser. The surfaces instrumented with piezoelectric ultrasonic scaler and Er,Cr:YSGG laser, alone or in combination with hand scaling and root planing, did not differ significantly (p>0.05) among themselves. No statistically significant differences (p>0.05) among groups were found as to the adhesion of blood components on root surface. Ultrasonic instrumentation and Er,Cr:YSGG irradiation produced rougher root surfaces than the use of curettes, but there were no differences among treatments with respect to the adhesion of blood components.

  9. Attempt of correlative observation of morphological synaptic connectivity by combining confocal laser-scanning microscope and FIB-SEM for immunohistochemical staining technique.

    Science.gov (United States)

    Sonomura, Takahiro; Furuta, Takahiro; Nakatani, Ikuko; Yamamoto, Yo; Honma, Satoru; Kaneko, Takeshi

    2014-11-01

    Ten years have passed since a serial block-face scanning electron microscopy (SBF-SEM) method was developed [1]. In this innovative method, samples were automatically sectioned with an ultramicrotome placed inside a scanning electron microscope column, and the block surfaces were imaged one after another by SEM to capture back-scattered electrons. The contrast-inverted images obtained by the SBF-SEM were very similar to those acquired using conventional TEM. SFB-SEM has made easy to acquire image stacks of the transmission electron microscopy (TEM) in the mesoscale, which is taken with the confocal laser-scanning microcopy(CF-LSM).Furthermore, serial-section SEM has been combined with the focused ion beam (FIB) milling method [2]. FIB-incorporated SEM (FIB-SEM) has enabled the acquisition of three-dimensional images with a higher z-axis resolution com- pared to ultramicrotome-equipped SEM.We tried immunocytochemistry for FIB-SEM and correlated this immunoreactivity with that in CF-LSM. Dendrites of neurons in the rat neostriatum were visualized using a recombinant viral vector. Moreover, the thalamostriatal afferent terminals were immunolabeled with Cy5 fluorescence for vesicular glutamate transporter 2 (VGluT2). After detection of the sites of terminals apposed to the dendrites by using CF-LSM, GFP and VGluT2 immunoreactivities were further developed for EM by using immunogold/silver enhancement and immunoperoxidase/diaminobenzidine (DAB) methods, respectively.We showed that conventional immuno-cytochemical staining for TEM was applicable to FIB-SEM. Furthermore, several synaptic contacts, which were thought to exist on the basis of CF-LSM findings, were confirmed with FIB-SEM, revealing the usefulness of the combined method of CF-LSM and FIB-SEM.

  10. In vitro studies of morphological changes in enamel surface after Er:YAG and Nd:YAG laser irradiation, by SEM; Estudo in vitro do efeito do laser Nd:YAG e Er:YAG sobre o esmalte dental humano atraves de microscopia eletronica de varredura

    Energy Technology Data Exchange (ETDEWEB)

    Verlangieri, Eleonora Jaeger

    2001-07-01

    The caries prevention by using laser irradiation has been investigated by many authors using various lasers with different irradiations conditions. The purpose of this study was to investigated the morphological changes in enamel surface after Er:YAG and Nd:YAG laser irradiation, in vitro, by SEM. Fifteen freshly extracted, intact, caries-free, human third molars, were used in this study. The coronary portions were sectioned, from buccal to lingual direction, in two half-parts. Each one was irradiated by a different laser. The first one was irradiated with water-air spray, by a Nd:YAG laser, at 1.084 nm wave length, at 10 W, 10 Hz, 100 mJ for 60 sec., with an optical fiber in contact mode (0,32 mm of diameter); and the other half, with water-air spray by an Er:YAG laser at 2,94 micrometers wave length at the parameters of 4 Hz, 80 mJ, 24.95 J/cm{sup 2} for 60 sec. The results of this study suggested that both lasers promoted morphological changes in the enamel surface enhancing resistance and can be an alternative clinical method for caries preventions. (author)

  11. Filler segmentation of SEM paper images based on mathematical morphology.

    Science.gov (United States)

    Ait Kbir, M; Benslimane, Rachid; Princi, Elisabetta; Vicini, Silvia; Pedemonte, Enrico

    2007-07-01

    Recent developments in microscopy and image processing have made digital measurements on high-resolution images of fibrous materials possible. This helps to gain a better understanding of the structure and other properties of the material at micro level. In this paper SEM image segmentation based on mathematical morphology is proposed. In fact, paper models images (Whatman, Murillo, Watercolor, Newsprint paper) selected in the context of the Euro Mediterranean PaperTech Project have different distributions of fibers and fillers, caused by the presence of SiAl and CaCO3 particles. It is a microscopy challenge to make filler particles in the sheet distinguishable from the other components of the paper surface. This objectif is reached here by using switable strutural elements and mathematical morphology operators.

  12. SEM investigation of Er:YAG laser apical preparation

    Science.gov (United States)

    Bǎlǎbuc, Cosmin; Todea, Carmen; Locovei, Cosmin; RǎduÅ£ǎ, Aurel

    2016-03-01

    Endodontic surgery involves the incision and flap elevation, the access to the root tip, its resection, the cavity retrograde preparation and filling it with biocompatible material that provides a good seal of the apex[1]. Apicoectomy is compulsory in endodontic surgery. The final stage involves the root retropreparation and the carrying out of the retrograde obturation. In order to perform the retrograde preparation the endodontist can use various tools such as lowspeed conventional handpieces, sonic and ultrasonic equipment. The ideal depth of the preparation should be 3 mm, exceeding this value may affect the long-term success of the obturation [2]. Resection at the depth of 3 mm reduces apical ramifications by 98% and lateral root canals by 93%. The ultrasonic retropreparation has numerous advantages compared to the dental drill. Firstly, the cavity will be in the axis of the tooth which implies a minimum destruction of the root canal morphology. The preparations are precise, and the cutting pattern is perpendicular to the long axis of the root, the advantage being the reduction in the number of dentinal tubules exposed at the resected area [3]. Therefore, the retrograde filling is the procedure when an inert and non-toxic material is compacted in the apically created cavity.[4,5]. The Er:YAG laser is the most common wavelength indicated for dental hard tissue preparation. Its natural selectivity offers a significant advantage compared to the conventional hard tissue preparation [6-9].The purpose of this in vitro study was to investigate the quality of Er:YAG laser apical third preparation using Scanning Electron Microscopy (SEM), in comparison with the conventional ultrasonic method.

  13. Soot morphology in laser pyrolysis

    Science.gov (United States)

    Sandu, Ion C.; Pasuk, I.; Morjan, Ion G.; Voicu, Ion N.; Alexandrescu, Rodica; Fleaca, Claudiu T.; Ciupina, Victor; Dumitrache, Florian V.; Soare, Iuliana; Ploscaru, Mihaela I.; Daniels, H.; Westwood, A.; Rand, B.

    2004-10-01

    Soots obtained by laser pyrolysis of different gaseous/vapor hydrocarbons were investigated. The morphology variation of carbon soot versus process parameters and nature of reactants was analyzed and discussed. The role of oxygen is essential in obtaining soot particles having considerable curved-layer content.

  14. Comparative study of etched enamel and dentin for the adhesion of composite resins with the Er:YAG 2,94 {mu}m laser and CO{sub 2} 9,6 {mu}m laser: morphological (SEM) and tensile bond strength analysis; Estudo comparativo do condicionamento do esmalte e dentina para a adesao de resinas compostas com os lasers Er:YAG 2,94 {mu}m e com o laser CO{sub 2} de 9,6 {mu}m: analise morfologica e de resistencia a tracao

    Energy Technology Data Exchange (ETDEWEB)

    Marraccini, Tarso Mugnai

    2002-07-01

    The aim of this study was to evaluate and compare the tensile bond strength of a composite resin adhered to the enamel and dentin which have received superficial irradiation with an Er:YAG laser (2.94 {mu}m) or with CO{sub 2} laser ( 9.6 {mu}m) and later on etched with the phosphoric acid at 35%. After the use of the adhesive system, resin cones were made on the etched surfaces by both lasers and tensile bond strength tests were performed. All samples were observed at the SEM - there was an increase of the degree of fusion and resolidification in the irradiated enamel and dentin samples with the CO{sub 2} laser (9.6 {mu}m), creating a vitrified layer with tiny craters. With the Er:YAG laser (2.94 {mu}m) there were typical morphological explosive microablation with the exposition of the tubules in the dentin.The surface acquired by the association of the CO{sub 2} laser ( 9.6 {mu}m) plus acid etching no longer presented the aspect of fusion being this layer completely removed. There were statistical significant differences among ali three methods of etching in the treatment of the enamel and dentin surface. The tensile bond strength test showed that etching of these enamel and dentin surfaces with acid exclusively (control group) presented great values, surpassing the values of the etching acquired with the Er:YAG laser (2.94 {mu}) plus acid or the CO{sub 2} laser (9.6 {mu}m) plus acid. With the parameters used in this experiment the Er:YAG laser (2.94 {mu}m) showed to be more effective than the CO{sub 2} laser (9.6 {mu}m) for the hard dental surfaces etching procedure. (author)

  15. Morphological modelling of three-phase microstructures of anode layers using SEM images.

    Science.gov (United States)

    Abdallah, Bassam; Willot, François; Jeulin, Dominique

    2016-07-01

    A general method is proposed to model 3D microstructures representative of three-phases anode layers used in fuel cells. The models are based on SEM images of cells with varying morphologies. The materials are first characterized using three morphological measurements: (cross-)covariances, granulometry and linear erosion. They are measured on segmented SEM images, for each of the three phases. Second, a generic model for three-phases materials is proposed. The model is based on two independent underlying random sets which are otherwise arbitrary. The validity of this model is verified using the cross-covariance functions of the various phases. In a third step, several types of Boolean random sets and plurigaussian models are considered for the unknown underlying random sets. Overall, good agreement is found between the SEM images and three-phases models based on plurigaussian random sets, for all morphological measurements considered in the present work: covariances, granulometry and linear erosion. The spatial distribution and shapes of the phases produced by the plurigaussian model are visually very close to the real material. Furthermore, the proposed models require no numerical optimization and are straightforward to generate using the covariance functions measured on the SEM images.

  16. The importance of scanning electron microscopy (sem in taxonomy and morphology of Chironomidae (Diptera

    Directory of Open Access Journals (Sweden)

    Andrzej Kownacki

    2015-07-01

    Full Text Available The paper reports on the value of scanning electron microscopy (SEM in the taxonomy and morphology of Chironomidae. This method has been relatively rarely used in Chironomidae studies. Our studies suggest that the SEM method provides a lot of new information. For example, the plastron plate of the thoracic horn of Macropelopia nebulosa (Meigen under light microscopy is visible as points, while under SEM we have found that it consists of a reticular structure with holes. By using SEM a more precise picture of the body structure of Chironomidae can be revealed. It allows researchers to explain inconsistencies in the existing descriptions of species. Another advantage of the SEM method is obtaining spatial images of the body and organs of Chironomidae. However, the SEM method also has some limitations. The main problem is dirt or debris (e.g. algae, mud, secretions, mucus, bacteria, etc., which often settles on the external surface of structures, especially those which are uneven or covered with hair. The dirt should be removed after collection of chironomid material because if left in place it can become chemically fixed to various surfaces. It unnecessarily remains at the surface and final microscopic images may contain artifacts that obscure chironomid structures being investigated. In this way many details of the surface are thus unreadable. The results reported here indicate that SEM examination helps us to identify new morphological features and details that will facilitate the identification of species of Chironomidae and may help to clarify the function of various parts of the body. Fast development of electron microscope technique allows us to learn more about structure of different organisms.

  17. Uncertainty in the use of MAMA software to measure particle morphological parameters from SEM images

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Daniel S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tandon, Lav [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-05

    The MAMA software package developed at LANL is designed to make morphological measurements on a wide variety of digital images of objects. At LANL, we have focused on using MAMA to measure scanning electron microscope (SEM) images of particles, as this is a critical part of our forensic analysis of interdicted radiologic materials. In order to successfully use MAMA to make such measurements, we must understand the level of uncertainty involved in the process, so that we can rigorously support our quantitative conclusions.

  18. Amalgam Surface Treatment by Different Output Powers of Er:YAG Laser:SEM Evaluation.

    Science.gov (United States)

    Hosseini, Mohammad Hashem; Hassanpour, Mehdi; Etemadi, Ardavan; Ranjbar Omrani, Ladan; Darvishpour, Hojat; Chiniforush, Nasim

    2015-01-01

    The purpose of this study was to evaluate amalgam surfaces treated by different output powers of erbium-doped yttrium aluminum garnet (Er:YAG) laser by scanning electron microscope (SEM). Twenty-one amalgam blocks (8 mm × 8 mm, 3 mm thickness) were prepared by condensing silver amalgam (into putty impression material. After keeping them for 24 hours in distilled water, they were divided into 7 groups as follow: G1: Er:YAG laser (1 W, 50 mJ), G2: Er:YAG laser (2 W, 100 mJ), G3: Er:YAG laser (3 W, 150 mJ), G4: Sandblast, G5: Sandblast + Er:YAG laser (1 W, 50 mJ), G6: Sandblast +Er:YAG laser (2 W, 100 mJ) and G7: Sandblast +Er:YAG laser (3 W, 150 mJ). Then after preparation of all samples, they were examined by SEM. The SEM results of amalgam surfaces treated by different output powers of Er:YAG laser showed some pitting areas with non-homogenous irregularities Conclusion: It seems that the application of sandblasting accompanied by Er:YAG laser irradiation can provide proper surface for bonding of orthodontic brackets.

  19. Morphological analysis of polymers on hair fibers by SEM and AFM

    Directory of Open Access Journals (Sweden)

    Valéria Fernandes Monteiro

    2003-12-01

    Full Text Available The polyquaternium 7® polymer is widely used in cosmetic formulations. Morphologic alterations in hair fibers were observed after the application of the polyquaternium 7® polymer, using SEM and AFM. Continuous applications of this product indicated that it accumulates on the fibers, improving the aspect of the hair surface. Quantitative analysis of the images obtained by AFM was undertaken. The data obtained for the hair surface roughness indicates that the fibers treated with the polymer presented higher roughness than the untreated hair fibers.

  20. Morphology of femtosecond laser-induced structural changes in KTP crystal

    Energy Technology Data Exchange (ETDEWEB)

    Li Yuhua [State Key Lab of Laser Technology and Wuhan National Lab for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei (China); Lu Peixiang [State Key Lab of Laser Technology and Wuhan National Lab for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei (China)]. E-mail: lupeixiang@mail.hust.edu.cn; Dai Nengli [State Key Lab of Laser Technology and Wuhan National Lab for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei (China); Long Hua [State Key Lab of Laser Technology and Wuhan National Lab for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei (China); Wang Ying [State Key Lab of Laser Technology and Wuhan National Lab for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei (China); Yu Benhai [State Key Lab of Laser Technology and Wuhan National Lab for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei (China)

    2006-11-30

    The morphology of structural changes in KTP crystal induced by single femtosecond laser pulse has been investigated by means of CCD camera, scanning electron microscopy (SEM) and atom force microscopy (AFM). The structurally changed region is depressed at energies close to the threshold for producing a structural change and melting ablation morphologies are observed as pulse energy is increased. Furthermore, periodic nanostructures are formed around the edge of the laser-induced spots.

  1. Effect of two bleaching agents on enamel morphology: a SEM study

    Directory of Open Access Journals (Sweden)

    Ghavam M.

    2005-05-01

    Full Text Available Statement of Problem: Bleaching materials are able to change the surface morphology as well as mineral and organic content of tooth structure. Considering that bleaching is done for aesthetic purpose, awareness of the possible effect of these materials on hard tissue is important, because it may affect the restorative treatments. Purpose: The aim of this study was comparing the effect of two bleaching materials, Kimia and Ultradent both containing 35% H2O2, on tooth enamel by SEM. Materials and Methods: Five intact central incisors were cut into three sections vertically and each part was randomly divided into three groups. Group 1 (control, without any bleaching. Group 2, bleached with Kimia 35% H2O2. Group 3, bleached with Ultradent 35% H2O2. Each tooth served as its own control. Then the samples were observed by SEM with 250 and 500 magnifications. Results: In the control group some scratches and small white grains were observed which seems to be the result of mastication trauma and pumice powder. In the other groups, morphologic changes like increased surface roughness, deepening of cracks, rod exposure and presence of new cracks were observed. The two experimental materials did not differ in these regards. Conclusion: It seems that both studied materials have limited destructive effects on tooth enamel which seems to be of no clinical importance.

  2. Application of BIB-SEM technology to characterize meso- and macropore morphology in coal

    Science.gov (United States)

    Giffin, Susan; Littke, Ralf; Klaver, Jop; Urai, Janos

    2013-04-01

    Coalbeds are very heterogenous in composition, which in turn affects the connectivity and transport of fluids within the coal. The composition of a coalbed influences the pore structure. Pore structure as well as pore size distribution are two important parameters used in estimating reservoir properties. This study examines the morphology and distribution of macro- and mesopores in coal samples, using broad ion beam (BIB) milling to prepare relief- and damage-free polished surfaces of coal samples for high-resolution SEM imaging. The BIB-sections of a few square millimeters are not large enough to be statistically representative so that the results cannot be easily interpreted from a coal seam standpoint. Therefore, porosity was investigated as a function of maceral type to characterize pore morphologies. Macerals were selected from the vitrinite group, e.g. telocollinite, and from the inertinite group, e.g. fusinite and macrinite. The selected macerals were BIB-milled parallel to bedding and subsequently milled perpendicular to bedding. Pore morphology and pore size distribution was examined in each of the milled sections. For a vitrinite maceral type, we found no visible macroporosity within the resolution limits of the SE detector. Pore morphology in an inertinite maceral is dependent on the original maceral. Fusinite yields large, elongated pores (often filled with mineralization), while macrinite shows comparatively smaller, rounder pores. The BIB-milled sections perpendicular to bedding often showed an alternating sequence of bedding, with bed thicknesses varying between a few micrometers to greater than half a millimeter. The distribution of pores is also reflected by bed thickness in the sections perpendicular to bedding, with many pores being concentrated in association with the beds. The distribution of pore sizes follows a similar power law at different magnifications of the same BIB-milled surface. Our results show that micropores and macropores in coal

  3. Laser induced plasma plume imaging and surface morphology of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Khaleeq-ur-Rahman, M. [Advanced Physics Laboratory, Department of Physics, University of Engineering and Technology, G.T. Road, Lahore 54890 (Pakistan); Siraj, K. [Advanced Physics Laboratory, Department of Physics, University of Engineering and Technology, G.T. Road, Lahore 54890 (Pakistan)], E-mail: ksiraj@uet.edu.pk; Rafique, M.S.; Bhatti, K.A.; Latif, A.; Jamil, H.; Basit, M. [Advanced Physics Laboratory, Department of Physics, University of Engineering and Technology, G.T. Road, Lahore 54890 (Pakistan)

    2009-04-15

    Shot-to-shot variation in the characteristics of laser produced plasma plume and surface profile of N-type silicon (1 1 1) are investigated. In order to produce plasma, a Q-switched Nd: YAG laser (1064 nm, 10 mJ, 9-14 ns) is tightly focused on silicon target in air at room temperature. Target was exposed in such a way that number of laser shots was increased from point to point in ascending order starting from single shot at first point. Target was moved 2 mm after each exposure. In order to investigate shot-to-shot variation in the time integrated emission intensity regions within the plasma plume, a computer controlled CCD based image capture system was employed. Various intensity regimes were found depending strongly on the number of incident laser pulses. Plasma plume length was also found to vary with the number of pulses. The topographic analysis of the irradiated Si was performed by Scanning Electron Microscope (SEM) which shows the primary mechanisms like thermal or non-thermal ablation depend on the number of shots. Surface morphological changes were also studied in terms of ripple formation, ejection, debris and re-deposition of material caused by laser beam at sample surface. The micrographs show ripples spacing versus wavelength dependence rule [{lambda} {approx} {lambda}/(1 - sin {theta})]. Intensity variations with number of shots are correlated with the surface morphology of the irradiated sample.

  4. Mapping the complex morphology of cell interactions with nanowire substrates using FIB-SEM.

    Directory of Open Access Journals (Sweden)

    Rafał Wierzbicki

    Full Text Available Using high resolution focused ion beam scanning electron microscopy (FIB-SEM we study the details of cell-nanostructure interactions using serial block face imaging. 3T3 Fibroblast cellular monolayers are cultured on flat glass as a control surface and on two types of nanostructured scaffold substrates made from silicon black (Nanograss with low- and high nanowire density. After culturing for 72 hours the cells were fixed, heavy metal stained, embedded in resin, and processed with FIB-SEM block face imaging without removing the substrate. The sample preparation procedure, image acquisition and image post-processing were specifically optimised for cellular monolayers cultured on nanostructured substrates. Cells display a wide range of interactions with the nanostructures depending on the surface morphology, but also greatly varying from one cell to another on the same substrate, illustrating a wide phenotypic variability. Depending on the substrate and cell, we observe that cells could for instance: break the nanowires and engulf them, flatten the nanowires or simply reside on top of them. Given the complexity of interactions, we have categorised our observations and created an overview map. The results demonstrate that detailed nanoscale resolution images are required to begin understanding the wide variety of individual cells' interactions with a structured substrate. The map will provide a framework for light microscopy studies of such interactions indicating what modes of interactions must be considered.

  5. Mapping the complex morphology of cell interactions with nanowire substrates using FIB-SEM.

    Science.gov (United States)

    Wierzbicki, Rafał; Købler, Carsten; Jensen, Mikkel R B; Lopacińska, Joanna; Schmidt, Michael S; Skolimowski, Maciej; Abeille, Fabien; Qvortrup, Klaus; Mølhave, Kristian

    2013-01-01

    Using high resolution focused ion beam scanning electron microscopy (FIB-SEM) we study the details of cell-nanostructure interactions using serial block face imaging. 3T3 Fibroblast cellular monolayers are cultured on flat glass as a control surface and on two types of nanostructured scaffold substrates made from silicon black (Nanograss) with low- and high nanowire density. After culturing for 72 hours the cells were fixed, heavy metal stained, embedded in resin, and processed with FIB-SEM block face imaging without removing the substrate. The sample preparation procedure, image acquisition and image post-processing were specifically optimised for cellular monolayers cultured on nanostructured substrates. Cells display a wide range of interactions with the nanostructures depending on the surface morphology, but also greatly varying from one cell to another on the same substrate, illustrating a wide phenotypic variability. Depending on the substrate and cell, we observe that cells could for instance: break the nanowires and engulf them, flatten the nanowires or simply reside on top of them. Given the complexity of interactions, we have categorised our observations and created an overview map. The results demonstrate that detailed nanoscale resolution images are required to begin understanding the wide variety of individual cells' interactions with a structured substrate. The map will provide a framework for light microscopy studies of such interactions indicating what modes of interactions must be considered.

  6. Dynamic-mechanical analysis and SEM morphology of wood flour/polypropylene composites

    Institute of Scientific and Technical Information of China (English)

    GUO Chui-gen; SONG Yong-ming; WANG Qing-wen; SHEN Chang-sheng

    2006-01-01

    A study was conducted to investigate the effects of compatibilizers, including Maleic anhydride grafted polypropylene (MA-PP) and maleic anhydride grafted ethylene-propylene-diene copolymer (MA-EPDM), on wood-flour/polypropylene (WF/PP) composites. WF/PP composites were prepared by direct extrusion profiles using a twin-screw/single-screw extruder system. DMA analysis showed that the loss factor of composites decreased and the storage modulus improved in the presence of MA-PP, which indicated much better interfacial adhesion between the PP matrix and wood flour filler than in the absence of compatibilizer. Morphological feature based on SEM observation showed that MA-PP and MA-EPDM improved the dispersion of the wood particles in the plastic matrix. MA-EPDM is a soft segment, although it improved the interfacial adhesion, storage modulus decreases with adding of MA-EPDM. As compatibilizer of wood-flour/polypropylene composites, both DMA analysis and SEM feature proved that MA-PP was superior to MA-EPDM.

  7. Nanosecond pulsed laser ablation of Ge investigated by employing photoacoustic deflection technique and SEM analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yaseen, Nazish; Bashir, Shazia; Shabbir, Muhammad Kaif; Jalil, Sohail Abdul; Akram, Mahreen; Hayat, Asma; Mahmood, Khaliq; Haq, Faizan-ul; Ahmad, Riaz; Hussain, Tousif

    2016-06-01

    Nanosecond pulsed laser ablation phenomena of single crystal Ge (100) has been investigated by employing photoacoustic deflection as well as SEM analysis techniques. Nd: YAG laser (1064 nm, 10 ns, 1–10 Hz) at various laser fluences ranging from 0.2 to 11 J cm{sup −2} is employed as pump beam to ablate Ge targets. In order to evaluate in-situe ablation threshold fluence of Ge by photoacoustic deflection technique, Continuous Wave (CW) He–Ne laser (632 nm, power 10 mW) is employed as a probe beam. It travels parallel to the target surface at a distance of 3 mm and after passing through Ge plasma it causes deflection due to density gradient of acoustic waves. The deflected signal is detected by photodiode and is recorded by oscilloscope. The threshold fluence of Ge, the velocity of ablated species and the amplitude of the deflected signal are evaluated. The threshold fluence of Ge comes out to be 0.5 J cm{sup −2} and is comparable with the analytical value. In order to compare the estimated value of threshold with ex-situe measurements, the quantitative analysis of laser irradiated Ge is performed by using SEM analysis. For this purpose Ge is exposed to single and multiple shots of 5, 10, 50 and 100 at various laser fluences ranging from 0.2 to 11 J cm{sup −2}. The threshold fluence for single and multiple shots as well as incubation coefficients are evaluated. It is observed that the value of incubation co-efficient decreases with increasing number of pulses and is therefore responsible for lowering the threshold fluence of Ge. SEM analysis also reveals the growth of various features such as porous structures, non-uniform ripples and blisters on the laser irradiated Ge. It is observed that both the fluence as well as number of laser shots plays a significant role for the growth of these structures.

  8. Nanosecond pulsed laser ablation of Ge investigated by employing photoacoustic deflection technique and SEM analysis

    Science.gov (United States)

    Yaseen, Nazish; Bashir, Shazia; Shabbir, Muhammad Kaif; Jalil, Sohail Abdul; Akram, Mahreen; Hayat, Asma; Mahmood, Khaliq; Haq, Faizan-ul; Ahmad, Riaz; Hussain, Tousif

    2016-06-01

    Nanosecond pulsed laser ablation phenomena of single crystal Ge (100) has been investigated by employing photoacoustic deflection as well as SEM analysis techniques. Nd: YAG laser (1064 nm, 10 ns, 1-10 Hz) at various laser fluences ranging from 0.2 to 11 J cm-2 is employed as pump beam to ablate Ge targets. In order to evaluate in-situe ablation threshold fluence of Ge by photoacoustic deflection technique, Continuous Wave (CW) He-Ne laser (632 nm, power 10 mW) is employed as a probe beam. It travels parallel to the target surface at a distance of 3 mm and after passing through Ge plasma it causes deflection due to density gradient of acoustic waves. The deflected signal is detected by photodiode and is recorded by oscilloscope. The threshold fluence of Ge, the velocity of ablated species and the amplitude of the deflected signal are evaluated. The threshold fluence of Ge comes out to be 0.5 J cm-2 and is comparable with the analytical value. In order to compare the estimated value of threshold with ex-situe measurements, the quantitative analysis of laser irradiated Ge is performed by using SEM analysis. For this purpose Ge is exposed to single and multiple shots of 5, 10, 50 and 100 at various laser fluences ranging from 0.2 to 11 J cm-2. The threshold fluence for single and multiple shots as well as incubation coefficients are evaluated. It is observed that the value of incubation co-efficient decreases with increasing number of pulses and is therefore responsible for lowering the threshold fluence of Ge. SEM analysis also reveals the growth of various features such as porous structures, non-uniform ripples and blisters on the laser irradiated Ge. It is observed that both the fluence as well as number of laser shots plays a significant role for the growth of these structures.

  9. Morphology of the European species of the aphid genus Eulachnus (Hemiptera: Aphididae: Lachninae) - A SEM comparative and integrative study.

    Science.gov (United States)

    Kanturski, Mariusz; Karcz, Jagna; Wieczorek, Karina

    2015-09-01

    Scanning electron microscopy (SEM) methods were used for the first time to elucidate the external morphology of the European species of the genus Eulachnus (Hemiptera: Aphididae: Lachninae), a representative genus of the conifer-feeding aphids tribe Eulachnini. We examined and compared the external morphology of apterous and alate viviparous females from the parthenogenetic generation as well as oviparous females and alate males belonging to the sexual generation. FE-SEM images based on HMDS and cryo-SEM preparation techniques revealed better image quality than the CPD technique in regard to surface tension and morphological signs of cell deteriorations (i.e., existence of depressions, drying artifacts and membrane blebs). Three morphologically different species groups "agilis", "brevipilosus" and "cembrae" were proposed due to the differences in head, antennae, legs and dorsal chaetotaxy as well as dorsal sclerotization. The most characteristic features and differences of representatives of these groups are presented and discussed.

  10. Tensile bond strength and SEM analysis of enamel etched with Er:YAG laser and phosphoric acid: a comparative study in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Luis H.; Tanaka, Celso Shin-Ite [Bandeirante University of Sao Paulo, Sao Paulo, SP (Brazil). Dept. of Prosthodontics; Lobo, Paulo D.C.; Villaverde, Antonio B.; Moriyama, Eduardo H.; Brugnera Junior, Aldo [University of Vale do Paraba, Sao Jose dos Campos, SP (Brazil). Inst. of Research and Development]. E-mail: abrugnera@uol.com.br; Moriyama, Yumi [Ontario Cancer Institute, Toronto, ON (Canada). Div. of Biophysics and Bioimaging; Watanabe, Ii-Sei [University of Sao Paulo (USP), SP (Brazil). Inst. of Biomedical Sciences

    2008-01-15

    Er:YAG laser has been studied as a potential tool for restorative dentistry due to its ability to selectively remove oral hard tissue with minimal or no thermal damage to the surrounding tissues. The purpose of this study was to evaluate in vitro the tensile bond strength (TBS) of an adhesive/composite resin system to human enamel surfaces treated with 37% phosphoric acid, Er:YAG laser ({lambda}=2.94 {mu}m) with a total energy of 16 J (80 mJ/pulse, 2Hz, 200 pulses, 250 ms pulse width), and Er:YAG laser followed by phosphoric acid etching. Analysis of the treated surfaces was performed by scanning electron microscopy (SEM) to assess morphological differences among the groups. TBS means (in MPa) were as follows: Er:YAG laser + acid (11.7 MPa) > acid (8.2 MPa) > Er:YAG laser (6.1 MPa), with the group treated with laser+acid being significantly from the other groups (p=0.0006 and p= 0.00019, respectively). The groups treated with acid alone and laser alone were significantly different from each other (p=0.0003). The SEM analysis revealed morphological changes that corroborate the TBS results, suggesting that the differences in TBS means among the groups are related to the different etching patterns produced by each type of surface treatment. The findings of this study indicate that the association between Er:YAG laser and phosphoric acid can be used as a valuable resource to increase bond strength to laser-prepared enamel. (author)

  11. A comparative SEM study between hand instrument and Er:YAG laser scaling and root planing.

    Science.gov (United States)

    Moghare Abed, A; Tawakkoli, M; Dehchenari, M A; Gutknecht, N; Mir, M

    2007-03-01

    Scaling and root planing are one of the most commonly used procedures for the treatment of periodontal diseases. Removal of calculus using conventional hand instruments is incomplete and rather time-consuming. In search for more efficient and less difficult instrumentation, investigators have proposed lasers as alternatives or adjuncts for scaling and root planing. The aim of the present study was to compare the effectiveness of subgingival scaling and root planing with erbium: yttrium, aluminium, garnet (Er:YAG) laser and hand instrumentation in vitro. The mesial and distal surfaces of 15 periodontal loosed extracted teeth were treated randomly either by hand instrumentation or by Er:YAG laser irradiation. After choosing the "very long pulse mode" (pulse duration of about 700 micros), the output energy of 160 mJ with 920-microm beam diameter (RO7 Perio tip, Fidelis, Fotona, Slovenia) and frequency of 12 Hz were selected, both according to the best results of past studies. In addition, air water spray was used during the procedures. The morphology of the root surface was evaluated by three observers with a scanning electron microscopy in magnifications of 50x and 400x. The result of this setting showed that the rate of remained roughness on treated root surfaces in two groups of hand instruments and Er:YAG laser had a meaningful difference: The surface roughness in Er:YAG laser group was more than in hand instruments group. The present study could demonstrate the in vitro capability of the Er:YAG laser for scaling and root planing in periodontitis, although the effectiveness of this setting did not reach that achieved by hand instrumentation. It could be concluded that lower frequency and long pulse duration maybe more suitable for the micro-morphology of root surface after treatment. This theory is going to be tested with the same laser instrument in the next study.

  12. Effects of root surface debridement using Er:YAG laser versus ultrasonic scaling - a SEM study.

    Science.gov (United States)

    Miremadi, S R; Cosyn, J; Schaubroeck, D; Lang, N P; De Moor, R J G; De Bruyn, H

    2014-11-01

    Despite promising results of Er:YAG laser in periodontal debridement, to date there is no consensus about the ideal settings for clinical use. This experimental clinical trial aimed to determine the effects of debridement using Er:YAG laser and to compare with ultrasonic treatment. Sixty-four teeth were divided into two in vivo and in vitro subgroups. Each tooth received ultrasonic treatment on one side and Er:YAG laser debridement at either 60, 100, 160 or 250 mJ pulse(-1) and at 10 Hz on the other side on a random basis. All samples were morphologically analyzed afterwards under scanning electron microscope for surface changes and dentinal tubules exposure. Treatment duration (d) was also recorded. Laser debridement produced an irregular, rough and flaky surface free of carbonization or meltdown while ultrasound produced a relatively smoother surface. The number of exposed dentinal tubules (n) followed an energy-dependent trend. The number of exposed tubules among the in vivo laser groups was n 60 mJ = n 100 mJ lasers led to significantly more dentinal exposure than ultrasound under in vivo condition. Within the in vitro laser groups, dentinal tubules exposure was n 60 mJ laser treatments at 100, 160 and 250 mJ led to significantly more dentinal denudation than ultrasound. Treatment duration (d) for the in vivo groups was d 60 mJ > d 100 mJ > d Ultrasound = d 160 mJ > d 250 mJ (P ≤ 0.046), while for the in vitro groups it was d 60 mJ > d 100 mJ = d Ultrasound = d 160 mJ >d 250 mJ (P ≤ 0.046). Due to excessive treatment duration and surface damage, Er:YAG laser debridement at 60 and 250 mJ pulse(-1), respectively, is not appropriate for clinical use. Although laser debridement at 100 and 160 mJ pulse(-1) seems more suitable for clinical application, compared to ultrasound the former is more time-consuming and the latter is more aggressive. Using a feedback device or lower pulse energies are recommended when using laser in closed field. © 2014 John Wiley

  13. Morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel.

    Science.gov (United States)

    Manuela Díaz-Monroy, Jennifer; Contreras-Bulnes, Rosalía; Fernando Olea-Mejía, Oscar; Emma Rodríguez-Vilchis, Laura; Sanchez-Flores, Ignacio

    2014-06-01

    Several scientific reports have shown the effects of Er:YAG laser irradiation on enamel morphology. However, there is lack of information regarding the morphological alterations produced by the acid attack on the irradiated surfaces. The aim of this study was to evaluate the morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel. Forty-eight enamel samples were divided into four groups (n = 12). GI (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm(2) ), 200 mJ (25.5 J/cm(2) ), and 300 mJ (38.2 J/cm(2) ), respectively, at 10 Hz without water irrigation. Enamel morphology was evaluated before-irradiation, after-irradiation, and after-acid dissolution, by scanning electron microscopy (SEM). Sample coating was avoided and SEM analysis was performed in a low-vacuum mode. To facilitate the location of the assessment area, a reference point was marked. Morphological changes produced by acid dissolution of irradiated enamel were observed, specifically on laser-induced undesired effects. These morphological changes were from mild to severe, depending on the presence of after-irradiation undesired effects.

  14. MORPHOLOGICAL ASPECTS OF HUMAN LENS CAPSULES - A COMPARATIVE LM, SEM AND TEM EXAMINATION

    NARCIS (Netherlands)

    JONGEBLOED, WL; KALICHARAN, D; LOS, LI; VANDERVEEN, G; WORST, JGF

    1991-01-01

    Lens capsules of patients of advanced age, obtained after extracapsular cataract surgery, were carefully prepared for a combined LM, TEM and SEM investigation, after preliminary washing and mounting onto a holder in a buffer solution. After pre-fixation with GA, samples were postfixed for LM/TEM and

  15. Effect of Er:YAG laser energy on the morphology of enamel/adhesive system interface

    Science.gov (United States)

    Delfino, Carina Sinclér; Souza-Zaroni, Wanessa Christine; Corona, Silmara Aparecida Milori; Pécora, Jesus Djalma; Palma-Dibb, Regina Guenka

    2006-10-01

    The aim of this study was to evaluate in vitro the influence of Er:YAG laser energy variation to cavity preparation on the morphology of enamel/adhesive system interface, using SEM. Eighteen molars were used and the buccal surfaces were flattened without dentine exposure. The specimens were randomly assigned to two groups, according to the adhesive system (conventional total-etching or self-etching), and each group was divided into three subgroups (bur carbide in turbine of high rotation, Er:YAG laser 250 mJ/4 Hz and Er:YAG laser 300 mJ/4 Hz) containing six teeth each. The enamel/adhesive system interface was serially sectioned and prepared for SEM. The Er:YAG laser, in general, produced a more irregular adhesive interface than the control group. For Er:YAG laser 250 mJ there was formation of a more regular hybrid layer with good tag formation, mainly in the total-etching system. However, Er:YAG laser 300 mJ showed a more irregular interface with amorphous enamel and fused areas, for both adhesive systems. It was concluded that cavity preparation with Er:YAG laser influenced on the morphology of enamel/adhesive system interface and the tissual alterations were more evident when the energy was increased.

  16. Influence of Surface Roughness on Morphology of Aluminum Alloy After Pulsed-Laser Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sung Ho; Kim, Chung Seok; Jhang, Kyung Young [Hanyang University, Seoul (Korea, Republic of); Shin, Wan Soon [Agency for Defense Development, Daejeon (Korea, Republic of)

    2011-09-15

    The objective of this study is to investigate the influence of surface roughness on the morphology of aluminum 6061- T6 alloy after irradiation with a Nd:YAG pulsed laser. The test specimen was prepared by a polishing process using a diamond paste (1 {mu}m) and emery polishing papers (100, 220, 600, 2400) to obtain different initial surface roughness. After irradiation with ten pulsed-laser shots, the surface morphology was examined by using scanning electron microscopy (SEM), optical microscopy (OM), and atomic force microscopy (AFM). The diameter of the melted zone increased with the surface roughness because the multiple reflections and absorption of the laser beam occurred on the surface because of the surface roughness, so that the absorptance of the laser beam changed. This result was verified using the relative absorptance calculated from the diameter of the melted zone with the surface roughness and the diameter increased with the average surface roughness.

  17. Morphology and Composition of Nanocrystalline Stabilized Zirconia using Sem-Eds System

    OpenAIRE

    Sunday Adesunloye JONAH; Patrick Ovie AKUSU; Tajudeen Oladele AHMED; Rabiu NASIRU

    2011-01-01

    Bismuth oxide of known mole percentages has been incorporated into zirconia matrix via co-precipitation method. The co-precipitated powders containing mixed oxides of bismuth and zirconium are dried and calcined in air at 200°C and 800°C respectively to obtain nanosized-stabilized zirconia. The microstructures and the composition of the nanosized-stabilized zirconia are investigated using Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS) at a low accel...

  18. Histological and SEM analysis of root cementum following irradiation with Er:YAG and CO2 lasers.

    Science.gov (United States)

    Almehdi, Aslam; Aoki, Akira; Ichinose, Shizuko; Taniguchi, Yoichi; Sasaki, Katia M; Ejiri, Kenichiro; Sawabe, Masanori; Chui, Chanthoeun; Katagiri, Sayaka; Izumi, Yuichi

    2013-01-01

    Recently, the Er:YAG and CO(2) lasers have been applied in periodontal therapy. However, the characteristics of laser-irradiated root cementum have not been fully analyzed. The aim of this study was to precisely analyze the alterations of root cementum treated with the Er:YAG and the CO(2) lasers, using non-decalcified thin histological sections. Eleven cementum plates were prepared from extracted human teeth. Pulsed Er:YAG laser contact irradiation was performed in a line at 40 mJ/pulse (14.2 J/cm(2)/pulse) and 25 Hz (1.0 W) under water spray. Continuous CO(2) laser irradiation was performed in non-contact mode at 1.0 W, and ultrasonic instrumentation was performed as a control. The treated samples were subjected to stereomicroscopy, scanning electron microscopy (SEM), light microscopy and SEM energy dispersive X-ray spectroscopy (SEM-EDS). The Er:YAG laser-treated cementum showed minimal alteration with a whitish, slightly ablated surface, whereas CO(2) laser treatment resulted in distinct carbonization. SEM analysis revealed characteristic micro-irregularities of the Er:YAG-lased surface and the melted, resolidified appearance surrounded by major and microcracks of the CO(2)-lased surface. Histological analysis revealed minimal thermal alteration and structural degradation of the Er:YAG laser-irradiated cementum with an affected layer of approximately 20-μm thickness, which partially consisted of two distinct affected layers. The CO(2)-lased cementum revealed multiple affected layers showing different structures/staining with approximately 140 μm thickness. Er:YAG laser irradiation used with water cooling resulted in minimal cementum ablation and thermal changes with a characteristic microstructure of the superficial layer. In contrast, CO(2) laser irradiation produced severely affected distinct multiple layers accompanied by melting and carbonization.

  19. Surface and morphological features of laser-irradiated silicon under vacuum, nitrogen and ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, Asma, E-mail: asmahayat@gcu.edu.pk; Bashir, Shazia; Akram, Mahreen; Mahmood, Khaliq; Iqbal, Muhammad Hassan

    2015-12-01

    Highlights: • Laser irradiation effects on Si surface have been explored. • An Excimer Laser was used as a source. • SEM analysis was performed to explore surface morphology. • Raman spectroscopy analysis was carried out to find crystallographical alterations. - Abstract: Laser-induced surface and structural modification of silicon (Si) has been investigated under three different environments of vacuum, nitrogen (100 Torr) and ethanol. The interaction of 1000 pulses of KrF (λ ≈ 248 nm, τ ≈ 18 ns, repetition rate ≈ 30 Hz) Excimer laser at two different fluences of 2.8 J/cm{sup 2} and 4 J/cm{sup 2} resulted in formation of various kinds of features such as laser induced periodic surface structures (LIPSS), spikes, columns, cones and cracks. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets is explored by Raman spectroscopy. SEM analysis exhibits a non-uniform distribution of micro-scale pillars and spikes at the central ablated regime of silicon irradiated at low laser fluence of 2.8 J/cm{sup 2} under vacuum. Whereas cones, pits, cavities and ripples like features are seen at the boundaries. At higher fluence of 4 J/cm{sup 2}, laser induced periodic structures as well as micro-columns are observed. In the case of ablation in nitrogen environment, melting, splashing, self-organized granular structures and cracks along with redeposition are observed at lower fluence. Such types of small scaled structures in nitrogen are attributed to confinement and shielding effects of nitrogen plasma. Whereas, a crater with multiple ablative layers is formed in the case of ablation at higher fluence. Significantly different surface morphology of Si is observed in the case of ablation in ethanol. It reveals the formation of cavities along with small scale pores and less redeposition. These results reveal that the growth of surface and morphological features of irradiated Si are strongly

  20. Morphology and Composition of Nanocrystalline Stabilized Zirconia using Sem-Eds System

    Directory of Open Access Journals (Sweden)

    Sunday Adesunloye JONAH

    2011-12-01

    Full Text Available Bismuth oxide of known mole percentages has been incorporated into zirconia matrix via co-precipitation method. The co-precipitated powders containing mixed oxides of bismuth and zirconium are dried and calcined in air at 200°C and 800°C respectively to obtain nanosized-stabilized zirconia. The microstructures and the composition of the nanosized-stabilized zirconia are investigated using Scanning Electron Microscopy (SEM coupled with Energy Dispersive X-ray Spectroscopy (EDS at a low accelerating voltage of 5kV. The results revealed that the powders are homogenously sintered with particle size having typical dimensions in the range of ~1.0-255µm. Energy dispersive X-ray spectroscopic (EDS analysis of the solid solutions confirm a predominance in the concentration of bismuth and zirconium while sodium, chlorine, and oxygen are present in minor concentration. The quantitative analytic results from EDS were used to determine Zr/Bi ratio.

  1. Calibration of ultra high speed laser engraving processes by correlating influencing variables including correlative evaluation with SEM and CLSM

    Science.gov (United States)

    Bohrer, Markus; Vaupel, Matthias; Nirnberger, Robert; Weinberger, Bernhard

    2016-03-01

    Laser engraving is used for decades as a well-established process e. g. for the production of print and embossing forms for many goods in daily life, e. g. decorated cans and printed bank notes. Up to now it is more or less a so-called fire-and-forget process. From the original artist's plan to the digitization, then from the laser source itself (with electronic signals, RF and plasma discharge regarding CO2 lasers) to the behavior of the optical beam delivery — especially if an AOM is used — to the interaction of the laser beam with the material itself is a long process chain. The most recent results using CO2 lasers with AOMs and the research done with scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM) — as a set for correlative microscopy to evaluate the high speed engraving characteristics — are presented in this paper.

  2. Morphological study of the European hedgehog (Erinaceus europaeus) tongue by SEM and LM.

    Science.gov (United States)

    Akbari, Ghasem; Babaei, Mohammad; Hassanzadeh, Belal

    2017-02-03

    The hedgehog tongue is a tactile and taste organ which carries out various functions. Detailed functional and morphological studies are required to clearly define the relationship of the hedgehog tongue with taste, food palatability, mastication and swallowing of food, as well as the production of sounds. The aim of this study was to determine the relationship between the morphological characteristics of the European hedgehog tongue and the lifestyle of this animal, as well as to compare findings with the results of studies on other vertebrates. Gross and micro-anatomical light and scanning electron microscopy studies revealed that the hedgehog tongue could be divided in three areas, namely the apex, body and root. A keratinized stratified squamous epithelium, which was smooth on the ventral surface but bore four types of papillae on the dorsal surface, lined the tongue. Three types of these papillae were found to have gustatory functions and to express their activity in close relation with the salivary glands. These simple conical filiform papillae were situated caudally and distributed one after the other without a break. The dome-shaped fungiform papillae on the apex, with the highest distribution rate on the apex edge, were small, but those on the body and root were large. The three circular vallate papillae were arranged in a triangular shape. The foliate papillae with a few tiny projections, found in a shallow furrow, were situated between the root and the body. Most of the nerve fibers observed in different sections of the tongue tissue were of the unmyelinated type, confirming that the main task of the hedgehog tongue was its gustatory function.

  3. Morphology Characterization of Uranium Particles From Laser Ablated Uranium Materials

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In the study, metallic uranium and uranium dioxide material were ablated by laser beam in order to simulate the process of forming the uranium particles in pyrochemical process. The morphology characteristic of uranium particles and the surface of

  4. A bacterial spore model of pulsed electric fields on spore morphology change revealed by simulation and SEM.

    Science.gov (United States)

    Qiu, Xing; Lee, Yin Tung; Yung, Pun To

    2014-01-01

    A two-layered spore model was proposed to analyze morphological change of bacterial spores subjected under pulsed electric fields. The outer layer, i.e. spore coat, was defined by Mooney-Rivlin hyper-elastic material model. The inner layer, i.e. peptidoglycan and spore core, was modeled by applying additional adhesion forces. The effect of pulsed electric fields on surface displacement was simulated in COMSOL Multiphysics and verified by SEM. The electro-mechanical theory, considering spore coat as a capacitor, was used to explain concavity; and the thin viscoelastic film theory, considering membrane bilayer as fluctuating surfaces, was used to explain leakage forming. Mutual interaction of external electric fields, charged spores, adhesion forces and ions movement were all predicted to contribute to concavity and leakage.

  5. Thermal damage study on diamond tools at varying laser heating time and temperature by Raman spectroscopy and SEM

    CSIR Research Space (South Africa)

    Masina, BN

    2011-07-01

    Full Text Available damage study on diamond tools at varying laser heating time and temperature by Raman spectroscopy and SEM BN Masina1, BW Mwakikunga2, M Elayaperumal2, A Forbes1, and R Bodkin3 1CSIR National Laser Centre, PO BOX 395, Pretoria 0001, South Africa 2CSIR... Slide 11 Optical images at the surface of the PCD layer Initial 15 min 968 K 25 min 979 K 5 min 895 K Dark phase is cobalt or tungsten Grey phase is diamond Slide 12 Raman shift at the surface of the PCD layer 600 800 1000 1200 1400 1600 1800 2000 0 2000...

  6. Effect of Irradiation Parameters on Morphology of Polishing DF2 (AISI-O1 Surface by Nd:YAG Laser

    Directory of Open Access Journals (Sweden)

    Wei Guo

    2007-01-01

    Full Text Available Pulse Nd:YAG laser was used to polish DF2 cold work steel. Influence of irradiation parameters on the 3D surface morphology was studied by 3D profilometer, scanning electron microscopy (SEM, and atomic force microscope (AFM. Results among the tests showed when DF2 specimens were irradiated with parameters of (i laser input energy P=1 J, (ii pulse feedrate=300 mm/min, (iii pulse duration (PD =3 milliseconds, and (iv pulse frequency f=20∼25 Hz, laser polishing of DF2 cold work steel seemed to be successful.

  7. Imaging of intracellular spherical lamellar structures and tissue gross morphology by a focused ion beam/scanning electron microscope (FIB/SEM)

    Energy Technology Data Exchange (ETDEWEB)

    Drobne, Damjana [Department of Biology, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia)], E-mail: damjana.drobne@bf.uni-lj.si; Milani, Marziale [Materials Science Department, University of Milano-Bicocca, Via Cozzi 53, I-20125 Milano (Italy); Leser, Vladka [Department of Biology, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia); Tatti, Francesco [FEI Italia, Via Cervi 40, I-00139 Roma (Italy); Zrimec, Alexis [Institute of Physical Biology, Velika Loka 90, SI-1290 Grosuplje (Slovenia); Znidarsic, Nada; Kostanjsek, Rok; Strus, Jasna [Department of Biology, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia)

    2008-06-15

    We report the use of a focused ion beam/scanning electron microscope (FIB/SEM) for simultaneous investigation of digestive gland epithelium gross morphology and ultrastructure of multilamellar intracellular structures. Digestive glands of a terrestrial isopod (Porcellio scaber, Isopoda, Crustacea) were examined by FIB/SEM and by transmission electron microscopy (TEM). The results obtained by FIB/SEM and by TEM are comparable and complementary. The FIB/SEM shows the same ultrastructural complexity of multilamellar intracellular structures as indicated by TEM. The term lamellar bodies was used for the multillamellar structures in the digestive glands of P. scaber due to their structural similarity to the lamellar bodies found in vertebrate lungs. Lamellar bodies in digestive glands of different animals vary in their abundance, and number as well as the thickness of concentric lamellae per lamellar body. FIB/SEM revealed a connection between digestive gland gross morphological features and the structure of lamellar bodies. Serial slicing and imaging of cells enables easy identification of the contact between a lamellar body and a lipid droplet. There are frequent reports of multilamellar intracellular structures in different vertebrate as well as invertebrate cells, but laminated cellular structures are still poorly known. The FIB/SEM can significantly contribute to the structural knowledge and is always recommended when a link between gross morphology and ultrastrucutre is investigated, especially when cells or cellular inclusions have a dynamic nature due to normal, stressed or pathological conditions.

  8. Morphological Peculiarities Of Laser Surgical Wounds

    Science.gov (United States)

    Yeliseenko, Vladimir I.

    1988-06-01

    Under the laser continuous irradiation one can observe on tissues and organs a whole complex of dystrophic processes including the coagulation necrosis as well as impairements in hemo- and microcirculation. The peculiarity of the inflammatory reaction in the healing process in laser wounds lies in an absence of demarcation leucocytic infiltration and lack of edema on a border of intact tissues and those with thermal necrosis; the healing process is characterised as well as with early proliferative phase. The main role in the reparative process belongs to cells of mononuclear phagocytic system ( macrophages ), wich make the reparative process like an aseptic productive inflammation.

  9. SURFACE MORPHOLOGY OF CARBON FIBER POLYMER COMPOSITES AFTER LASER STRUCTURING

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, Adrian S [ORNL; Chen, Jian [ORNL; Jones, Jonaaron F. [University of Tennessee (UT); Alexandra, Hackett [University of Tennessee (UT); Jellison Jr, Gerald Earle [ORNL; Daniel, Claus [ORNL; Warren, Charles David [ORNL; Rehkopf, Jackie D. [Plasan Carbon Composites

    2015-01-01

    The increasing use of Carbon Fiber Polymer Composite (CFPC) as a lightweight material in automotive and aerospace industries requires the control of surface morphology. In this study, the composites surface was prepared by ablating the resin in the top fiber layer of the composite using an Nd:YAG laser. The CFPC specimens with T700S carbon fiber and Prepreg - T83 resin (epoxy) were supplied by Plasan Carbon Composites, Inc. as 4 ply thick, 0/90o plaques. The effect of laser fluence, scanning speed, and wavelength was investigated to remove resin without an excessive damage of the fibers. In addition, resin ablation due to the power variation created by a laser interference technique is presented. Optical property measurements, optical micrographs, 3D imaging, and high-resolution optical profiler images were used to study the effect of the laser processing on the surface morphology.

  10. Surface and morphological features of laser-irradiated silicon under vacuum, nitrogen and ethanol

    Science.gov (United States)

    Hayat, Asma; Bashir, Shazia; Akram, Mahreen; Mahmood, Khaliq; Iqbal, Muhammad Hassan

    2015-12-01

    Laser-induced surface and structural modification of silicon (Si) has been investigated under three different environments of vacuum, nitrogen (100 Torr) and ethanol. The interaction of 1000 pulses of KrF (λ ≈ 248 nm, τ ≈ 18 ns, repetition rate ≈ 30 Hz) Excimer laser at two different fluences of 2.8 J/cm2 and 4 J/cm2 resulted in formation of various kinds of features such as laser induced periodic surface structures (LIPSS), spikes, columns, cones and cracks. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets is explored by Raman spectroscopy. SEM analysis exhibits a non-uniform distribution of micro-scale pillars and spikes at the central ablated regime of silicon irradiated at low laser fluence of 2.8 J/cm2 under vacuum. Whereas cones, pits, cavities and ripples like features are seen at the boundaries. At higher fluence of 4 J/cm2, laser induced periodic structures as well as micro-columns are observed. In the case of ablation in nitrogen environment, melting, splashing, self-organized granular structures and cracks along with redeposition are observed at lower fluence. Such types of small scaled structures in nitrogen are attributed to confinement and shielding effects of nitrogen plasma. Whereas, a crater with multiple ablative layers is formed in the case of ablation at higher fluence. Significantly different surface morphology of Si is observed in the case of ablation in ethanol. It reveals the formation of cavities along with small scale pores and less redeposition. These results reveal that the growth of surface and morphological features of irradiated Si are strongly dependent upon the laser fluence as well as environmental conditions. The difference in surface morphology is attributable to cooling, confinement and shielding effects as well as difference in plasma temperature, density and pressure of environmental media that corresponds to different energy deposition

  11. Experimental study on thermic effects, morphology and function of guinea pig cochlea: a comparison between the erbium:yttrium-aluminum-garnet laser and carbon dioxide laser.

    Science.gov (United States)

    Ren, Dong-Dong; Chi, Fang-Lu

    2008-08-01

    Surgery of the inner ear requires atraumatic techniques to preserve the morphology of the inner ear. Recent experiment and clinical studies have demonstrated that several laser systems are suitable for cochleostomy. The goal of this study was to quantify the thermic effects, morphology and function of guinea pig cochlea in vivo by comparing the erbium:yttrium-aluminum-garnet (Er:YAG) laser and carbon dioxide (CO(2)) laser and to determine the optimum laser parameters for safe clinical treatment. A fenestration in the basal cochlear turn of guinea pigs was created. A type K thermocouple was placed on the membrane of round window to detect the local temperature change during laser irradiation. The auditory evoked brainstem response (ABR) was measured before and after laser application. Confocal laser microscopy and scanning electron microscopy (SEM) was used for cochlear morphology. An increased hearing loss immediately and 4 weeks later after irradiation was observed in animals with the higher power CO(2) laser in accordance with a higher temperature increase during laser application. In contrast, a wider safety scope of Er:YAG application in cochleostomy was presented with little temperature increase. These findings were correlated with the ultrastructural changes in guinea pig cochlea. The Er:YAG and CO(2) lasers are shown to be safe if the total amount of energy is kept within the limits applied in this study. In addition, on this preliminary basis by guinea pig laser cochleostomy, Er:YAG laser maybe less damaging to inner ear structures than CO(2) laser with a larger safety scope and less thermic effects. (c) 2008 Wiley-Liss, Inc.

  12. SEM evaluation of the hybrid layer after cavity preparation with Er:YAG laser.

    Science.gov (United States)

    de Barceleiro, Marcos Oliveira; Dias, Kátia Regina Hostílio Cervantes; Sales, Helena Xavier; Silva, Bárbara Carvalho; Barceleiro, Cristiane Gomes

    2008-01-01

    This study compared the thickness of the hybrid layer formed using Scotchbond Multi-Purpose Plus, Single Bond 2, Prime & Bond 2.1 and Xeno III on a dentin surface prepared with a diamond bur in a high speed handpiece or prepared with an Er:YAG laser used with two parameters of pulse energy (200 and 400 mJ) and two parameters of frequency (4 and 6 Hz). Flat dentin surfaces obtained from 20 human third molars were treated with the two methods and were then prepared with the dentin adhesive systems according to the manufacturers' instructions. After a layer of composite was applied, the specimens were sectioned, flattened, polished and prepared for Scanning Electronic Microscopy observation. Five different measurements of the hybrid layer thickness were obtained along the bonded surface in each specimen. The results were statistically analyzed using Analysis of Variance and Student-Newman-Keuls tests (p cavity preparation method, four groups were formed: Group I (diamond bur) > Group II (Laser 200 mJ/4 Hz) = Group III (Laser 200 mJ/6 Hz) > Group IV (Laser 400 mJ/4 Hz) > Group V (Laser 400 mJ/6 Hz). When comparing the dentin adhesive systems, there were no statistically significant differences. These results showed that the four tested dentin adhesive systems produced a 2.90 +/- 1.71 microm hybrid layer in dentin prepared with a diamond bur. This hybrid layer was regular and routinely found. In the laser groups, the dentin adhesive systems produced hybrid layers ranging from 0.41 +/- 1.00 microm to 2.06 +/- 2.49 microm, which were very irregular and not routinely found. It was also concluded that the Er:YAG laser, with the parameters used in this experiment, has a negative influence on the formation of a hybrid layer and cavity preparation methods influence formation of the hybrid layer.

  13. Comparison of bond strength and surface morphology of dental enamel for acid and Nd-YAG laser etching

    Science.gov (United States)

    Parmeswearan, Diagaradjane; Ganesan, Singaravelu; Ratna, P.; Koteeswaran, D.

    1999-05-01

    Recently, laser pretreatment of dental enamel has emerged as a new technique in the field of orthodontics. However, the changes in the morphology of the enamel surface is very much dependent on the wavelength of laser, emission mode of the laser, energy density, exposure time and the nature of the substance absorbing the energy. Based on these, we made a comparative in vitro study on laser etching with acid etching with reference to their bond strength. Studies were conducted on 90 freshly extracted, non carious, human maxillary or mandibular anteriors and premolars. Out of 90, 60 were randomly selected for laser irradiation. The other 30 were used for conventional acid pretreatment. The group of 60 were subjected to Nd-YAG laser exposure (1060 nm, 10 Hz) at differetn fluences. The remaining 30 were acid pretreated with 30% orthophosphoric acid. Suitable Begg's brackets were selected and bound to the pretreated surface and the bond strength were tested using Instron testing machine. The bond strength achieved through acid pretreatment is found to be appreciably greater than the laser pretreated tooth. Though the bond strength achieved through the acid pretreated tooth is found to be significantly greater than the laser pretreated specimens, the laser pretreatement is found to be successful enough to produce a clinically acceptable bond strength of > 0.60 Kb/mm. Examination of the laser pre-treated tooth under SEM showed globule formation which may produce the mechanical interface required for the retention of the resin material.

  14. Morphology of Near- and Semispherical Melted Chips after the Grinding Processes Using Sol-Gel Abrasives Based on SEM-Imaging and Analysis

    Directory of Open Access Journals (Sweden)

    W. Kapłonek

    2016-01-01

    Full Text Available Selected issues related to SEM-imaging and image analysis of spherical melted chips formed during the grinding process are presented and discussed. The general characteristics of this specific group of machining products are given. Chip formation phenomena, as well as their overall morphology, are presented using selected examples of near- and semispherical melted chips occurring singly or concentrated in clusters on the grinding wheel surface after the machining process. Observation of the spherical melted chips and acquisition of their images were carried out for grinding wheel active surfaces with microcrystalline sintered corundum abrasive grains SG™ after the internal cylindrical grinding process of a 100Cr6 steel and Titanium Grade 2® alloy by use of a scanning electron microscope, JEOL JSM-5500LV. Analysis of the obtained SEM micrographs was carried out by Image-Pro® Plus 5.0 software to determine the selected geometrical parameters describing the morphological features of the assessed chips.

  15. Effects of NaOCl or Combination of NaOCl and Various Acids on Dentin Surface Morphology: A SEM Study

    Directory of Open Access Journals (Sweden)

    Gökçe Kağan

    2014-03-01

    Full Text Available The aim of this study was to evaluate by SEM morphological changes of dentin surfaces under the use of 5% NaOCl before applying different acids for etching. In the study, dentin surfaces were prepared from the middle third of 20 non-carious human third molars. Samples were divided into 2 groups with 3 subgroups each. In the first group, no application was performed on dentin surfaces. In the second group, 5% NaOCl was applied for 60 seconds on the dentin surfaces then rinsed with distilled water for 5 seconds. In all of the subgroups, dentin surfaces were etched by different conditioning agents for 15 seconds then rinsed for 30 seconds. After surface applications, all of the specimens were placed in distilled water. Morphological changes of dentin surfaces were determined by SEM. The results were evaluated by the scoring system based on Brannström et al.

  16. Analyse titanium surface irradiated with laser, with and without deposited of durapatite Análise da superfície de titânio sob efeito do laser com e sem deposição de hidroxiapatita

    Directory of Open Access Journals (Sweden)

    Karin Ellen Sisti

    2006-01-01

    Full Text Available PURPOSE: The aim of this study was to analyse the surface of titanium implants using disc irradiated with lasers. METHODS: Titanium discs were irradiated with laser high insensitive (Nd-YAG, deposited durapatite and used thermal treatment. Sample received qualitative morphological analyse trough micrographics with many size in SEM (Scanning Electron Microscopy. RESULTS: Surface laser irradiation shows roughness and isomorphic characteristic. The durapatite amplified the titanium surface area by method biomimetic. CONCLUSION: The surface treatment presented more deposition of durapatite, roughness on the surface, better isomorphic characteristic and increase quantitative in titanium surface area, samples shows rugous, roughness and homogeneity there is not found in the implants available at the market.OBJETIVO: Estudar a superfície de implantes osseointegráveis utilizando discos de titânio irradiados com feixe de laser. MÉTODOS: A amostra foi irradiada com feixes de laser de alta intensidade (Nd-YAG, posteriormente depositado hidróxiapatita e submetido a tratamento térmico. Foi analisada sob MEV (Microscópio Eletrônico de Varredura e realizada análise morfológica qualitativa com microfotografias em vários aumentos. RESULTADOS: A superfície irradiada com laser apresentou deformidade superficial e característica isomórfica; a aplicação de hidroxiapatita pelo método de biomimético aumentou quantitativamente a área da superfície de titânio. CONCLUSÃO: A deposição de hidroxiapatita apresentou melhor característica isomórfica e aumento quantitativo da área superficial estudada, a amostra demonstrou características não encontradas nos implantes disposto no mercado.

  17. Microhardness and morphological changes induced by Nd: Yag laser on dental enamel: an in vitro study

    Directory of Open Access Journals (Sweden)

    Rossella Bedini

    2010-06-01

    Full Text Available The aim of this work was a scanning electron microscopy (SEM evaluation of the hardness and morphological changes of enamel irradiated by neodymium: yttrium aluminium garnet (Nd:YAG laser with different energy levels. Twenty-eight human teeth samples were divided into 4 groups: control, where enamel surface was not lased, and 3 test treated with 3 different levels of energy power 0.6, 1.2 and 2.4 Watt, respectively. In each group, 5 samples underwent Vickers microhardness test and 2 samples were processed for SEM. No significant differences between treated and non treated samples were found by micro-hardness test. However, by SEM, test samples showed a rougher enamel surface than control. Specifically, the 0.6 Watt treated samples showed vertical scratches and glass-like areas, while in the other 2 groups enamel surface was covered by craters and cracks. These findings suggest that enamel should be lased at a low energy level to preserve its integrity and reduce demineralization, and thus for dental caries prevention purposes; while high energy level creates a retentive surface suitable for sealant or composite anchorage.

  18. SEM - Morphological evaluation of the root apex in human primary teeth with different degrees of pulpal and periapical pathology

    OpenAIRE

    2007-01-01

    O objetivo deste estudo foi avaliar a morfologia da superfície externa de ápices radiculares de dentes decíduos de humanos com necrose pulpar, com e sem lesão periapical visível radiograficamente, e de dentes com vitalidade pulpar, por meio da microscopia eletrônica de varredura (MEV). Dezenove dentes foram extraídos sendo cinco dentes com vitalidade pulpar (Grupo I), seis com necrose pulpar sem lesão periapical (Grupo II) e oito com necrose pulpar e lesão periapical (Grupo III). Os dentes (i...

  19. Effects of isothermal heat treatment on nanostructured bainite morphology and microstructures in laser cladded coatings

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yanbing [Shanghai Key Lab of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Feng, Kai; Lu, Fenggui; Zhang, Ke [Shanghai Key Lab of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composite, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Li, Zhuguo, E-mail: lizg@sjtu.edu.cn [Shanghai Key Lab of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Hosseini, Seyed Reza Elmi [Shanghai Key Lab of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang, Min [Shanghai Key Lab of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composite, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-12-01

    Highlights: • Nanobainitic coatings under 200, 250 and 300 °C heat treatments are fabricated. • The size of bainite sheaves increased with the isothermal temperature increasing. • Textured and chaotic distributions are observed in 200 and 300 °C microstructures. • The evolution model of nanobainite morphology is established and analyzed. • The bainitic ferrite of 200 °C heat treatment has a true thickness of 45 nm. - Abstract: Laser cladding and subsequent isothermal heat treatments have been used to fabricate nanostructured bainitic coatings. XRD has been used to determine the kinetics of bainitic transformation process. OM, SEM and TEM have been used to characterize the morphology and microstructures at different stages of transformation. The results showed that at the initial stage of bainitic transformation, the bainite sheaves are short and thin at a relatively low transformation temperature. The fully transformed bainitic microstructure obtained at a relatively high temperature present a textured morphology. The chaotic growth orientations of the sheaves and the island like of the retained austenite have been observed at the low transformation temperature. A simple model has been established to describe the microstructures and the bainite sheaves growth evolutions during the isothermal holding at the different transformed temperatures. The morphology and distribution of the bainite in the coatings were analyzed by using the nucleation and growth rate of bainitic transformation theories, which is consisted with the experiment results.

  20. Morphological assessment of dentine and cementum following apicectomy with Zekrya burs and Er:YAG laser associated with direct and indirect Nd:YAG laser irradiation.

    Science.gov (United States)

    de Moura, Abilio Albuquerque Maranhão; Moura-Netto, Cacio; Barletta, Fernando Branco; Vieira-Júnior, Nilson Dias; Eduardo, Carlos de Paula

    2010-04-01

    This study aimed to assess the apical surface morphology of maxillary central incisors resected 3.0 mm from the tooth apex using Zekrya burs or Er:YAG laser, with or without subsequent direct Nd:YAG laser irradiation (apical and buccal surfaces) and indirect irradiation (palatal surface). Forty maxillary central incisors were instrumented and obturated. The roots were divided into 4 groups according to the root resection method (Zekrya bur or Er:YAG laser - 1.8 W, 450 mJ, 4 Hz, 113 J/cm(2)) and further surface treatment (none or Nd:YAG laser - 2.0 W, 100 mJ, 20 Hz, 124 J/cm(2)). The teeth were prepared for SEM analysis. Scores ranging from 1 to 4 were attributed to cut quality and morphological changes. The data were analyzed by the Kruskal-Wallis test and by Dunn's test. SEM images showed irregular surfaces on the apical portions resected with Zekrya burs, with smear layer and grooves in the resected dentine and slight gutta-percha displacement and plasticization. On the other hand, apicectomies carried out with Er:YAG laser showed morphological changes compatible with ablated dentine, with rough surfaces and craters. In spite of the presence of plasticized gutta-percha, with the presence of bubbles, an irregular adaptation of the filling material to the root walls was also observed. Direct Nd:YAG laser irradiation of the apical and buccal surfaces of the resected roots resulted in areas of resolidification and fusion in the dentine and cementum, with a vitrified aspect; indirect Nd:YAG laser irradiation of the palatal surfaces yielded a lower number of changes in the cementum, with irregular resolidification areas. There were no differences in terms of cut quality between the use of burs and Er:YAG laser or between the 2 surfaces (apical and buccal) treated with Nd:YAG laser with direct irradiation. However, morphological changes were significantly less frequent on surfaces submitted to indirect irradiation (palatal) when compared with those directly irradiated

  1. Evaluation of the Morphological Characteristics of Laser-Irradiated Dentin

    Science.gov (United States)

    Lilaj, Bledar; Franz, Alexander; Degendorfer, Daniela; Moritz, Andreas

    2015-01-01

    Abstract Objective: The aim of this study was to investigate the effect of different energy settings of Er:YAG laser irradiation on dentin surface morphology with respect to the number of opened dentinal tubules. Background data: An ideally prepared dentin surface with opened dentinal tubules is a prerequisite for adhesive fixation. No study, however, has yet compared the numbers of opened dentinal tubules with regard to statistical differences. Methods: Conventional preparations using a bur with or without additional acid etching acted as control groups. Dentin specimens were prepared from human third molars and randomly divided into eight groups according to the energy settings of the laser (1, 1.5, 4, 6, 7.5, and 8 W) and two controls (bur and bur plus acid etching). After surface preparation, dentin surfaces were analyzed with a scanning electron microscope, and the number of opened dentinal tubules in a defined area was counted. Results: The control groups showed smooth surfaces with (bur plus acid etching) and without opened dentinal tubules (bur), whereas all laser-irradiated surfaces showed rough surfaces. Using the energy setting of 4 W resulted in significantly more opened dentinal tubules than the conventional preparation technique using the bur with additional acid etching. In contrast, the energy setting of 8 W showed significantly fewer opened dentinal tubules, and also exhibited signs of thermal damage. Conclusions: The Er:YAG laser with an energy setting of 4 W generates a dentin surface with opened dentinal tubules, a prerequisite for adhesive fixation. PMID:26389986

  2. Effects of Laser Shock Processing on Morphologies and Mechanical Properties of ANSI 304 Stainless Steel Weldments Subjected to Cavitation Erosion

    Science.gov (United States)

    Zhang, Lei; Lu, Jin-Zhong; Zhang, Yong-Kang; Ma, Hai-Le; Luo, Kai-Yu; Dai, Feng-Ze

    2017-01-01

    Effects of laser shock processing (LSP) on the cavitation erosion resistance of laser weldments were investigated by optical microscope (OM), scanning electron microscope (SEM) observations, roughness tester, micro hardness tester, and X-ray diffraction (XRD) technology. The morphological microstructures were characterized. Cumulative mass loss, incubation period, erosion rate, and damaged surface areas were monitored during cavitation erosion. Surface roughness, micro-hardness, and residual stress were measured in different zones. Results showed that LSP could improve the damage of morphological microstructures and mechanical properties after cavitation erosion. The compressive residual stresses were generated during the process of LSP, which was an effective guarantee for the improvement of the above mentioned properties. PMID:28772652

  3. Morphological and spectroscopic characterization of laser-ablated tungsten at various laser irradiances

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Mahreen; Bashir, Shazia; Hayat, Asma; Mahmood, Khaliq; Dawood, Asadullah [Government College University, Centre for Advanced Studies in Physics, Lahore (Pakistan); Rafique, Muhammad Shahid [University of Engineering and Technology, Department of Physics, Lahore (Pakistan); Bashir, M.F. [COMSATS Institute of Information Technology, Department of Physics, Lahore (Pakistan)

    2015-06-15

    The variation in surface morphology and plasma parameters of laser irradiated tungsten has been investigated as a function of irradiance. For this purpose, Nd:YAG laser (1064 nm, 10 ns, 10 Hz) is employed. Tungsten targets were exposed to various laser irradiances ranging from 6 to 50 GW/cm{sup 2} under ambient environment of argon at a pressure of 20 Torr. Scanning electron microscope analysis has been performed to analyze the surface modification of irradiated tungsten. It revealed the formation of micro- and nanoscale surface structures. In central ablated area, distinct grains and crack formation are observed, whereas peripheral ablated areas are dominated by cones and pinhole formation. It was observed that at irradiances exceeding a value of 13 GW/cm{sup 2}, the morphological trend of the observed structures has been changed from erosion to melting and re-deposition dominant phase. Ablation efficiency as a function of laser irradiance has also been investigated by measuring the crater depth using surface profilometry analysis. It is found to be maximum at an irradiance of 13 GW/cm{sup 2} and decreases at high laser irradiances. In order to correlate the accumulated effects of plasma parameters with the surface modification, laser-induced breakdown spectroscopy analysis has been performed. The electron temperature and number density of tungsten plasma have been evaluated at various laser irradiances. Initially with the increase of the laser irradiance up to 13 GW/cm{sup 2}, an increasing trend is observed for both plasma parameters due to enhanced energy deposition. Afterward, a decreasing trend is achieved which is attributed to the shielding effect. With further increase in irradiance, a saturation stage comes and insignificant changes are observed in plasma parameters. This saturation is explainable on the basis of the formation of a self-regulating regime near the target surface. Surface modifications of laser irradiated tungsten have been correlated with

  4. Effect of Er,Cr:YSGG and Er:YAG laser irradiation on the adhesion of blood components on the root surface and on root morphology

    OpenAIRE

    2012-01-01

    The aim of this study was to conduct an in vitro evaluation, by scanning electron microscopy (SEM), of the adhesion of blood components on root surfaces irradiated with Er,Cr:YSGG (2.78 mu m) or Er:YAG (2.94 mu m) laser, and of the irradiation effects on root surface morphology. Sixty samples of human teeth were previously scaled with manual instruments and divided into three groups of 20 samples each: G1 (control group) - no treatment; G2 - Er,Cr:YSGG laser irradiation; G3 - Er:YAG laser irr...

  5. AFM study of the effects of laser surface remelting on the morphology of Al-Fe aerospace alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pariona, Moises Meza, E-mail: mmpariona@uepg.br [Graduate Program in Engineering and Materials Science, State University of Ponta Grossa (UEPG), Ponta Grossa 84010-919, PR (Brazil); Teleginski, Viviane; Santos, Kelly dos; Leandro Ribeiro dos Santos, Everton; Aparecida de Oliveira Camargo de Lima, Angela [Graduate Program in Engineering and Materials Science, State University of Ponta Grossa (UEPG), Ponta Grossa 84010-919, PR (Brazil); Riva, Rudimar [Department of Aerospace Science and Technology, Institute for Advanced Studies (IEAv), Sao Jose dos Campos 12227-000, SP (Brazil)

    2012-12-15

    Laser beam welding has recently been incorporated into the fabrication process of aircraft and automobile structures. Surface roughness is an important parameter of product quality that strongly affects the performance of mechanical parts, as well as production costs. This parameter influences the mechanical properties such as fatigue behavior, corrosion resistance, creep life, etc., and other functional characteristics such as friction, wear, light reflection, heat transmission, lubrification, electrical conductivity, etc. The effects of laser surface remelting (LSR) on the morphology of Al-Fe aerospace alloys were examined before and after surface treatments, using optical microscopy (OM), scanning electron microscopy (SEM), low-angle X-ray diffraction (LA-XRD), atomic force microscopy (AFM), microhardness measurements (Vickers hardness), and cyclic voltammetry. This analysis was performed on both laser-treated and untreated sanded surfaces, revealing significant differences. The LA-XRD analysis revealed the presence of alumina, simple metals and metastable intermetallic phases, which considerably improved the microhardness of laser-remelted surfaces. The morphology produced by laser surface remelting enhanced the microstructure of the Al-Fe alloys by reducing their roughness and increasing their hardness. The treated surfaces showed passivity and stability characteristics in the electrolytic medium employed in this study. - Highlights: Black-Right-Pointing-Pointer The samples laser-treated and untreated showed significant differences. Black-Right-Pointing-Pointer The La-XRD revealed the presence of alumina in Al-1.5 wt.% Fe. Black-Right-Pointing-Pointer The laser-treated reducing the roughness and increasing the hardness. Black-Right-Pointing-Pointer The laser-treated surfaces showed characteristic passive in the electrolytic medium. Black-Right-Pointing-Pointer The laser-treated is a promising technique for applications technological.

  6. Investigation of mechanisms leading to laser damage morphology

    Science.gov (United States)

    Lamaignère, L.; Chambonneau, M.; Diaz, R.; Grua, P.; Courchinoux, R.; Natoli, J.-Y.; Rullier, J. L.

    2016-12-01

    The original damage ring pattern at the exit surface of fused silica induced by highly modulated nanosecond infrared laser pulses demonstrates the time dependence of damage morphology. Such a damage structure is used to study the dynamics of the plasma issued from open cracks. This pattern originates from electron avalanche in this plasma, which simultaneously leads to an ionization front displacement in air and a silica ablation process. Experiments have shown that the propagation speed of the detonation wave reaches about 20 km/s and scales as the cube root of the laser intensity, in good agreement with theoretical hydrodynamics modeling. During this presentation, we present the different phases and the associated mechanisms leading to this peculiar morphology: • During an incubation phase, a precursor defect provides energy deposit that drives the near surface material into a plasma state. • Next the silica plasma provides free electrons in the surrounding air, under laser irradiation an electron avalanche is initiated and generates a breakdown wave. • Then this breakdown wave leads to an expansion of the air plasma. This latter is able to heat strongly the silica surface as well as generate free electrons in its conduction band. Hence, the silica becomes activated along the breakdown wave. • When the silica has become absorbent, an ablation mechanism of silica occurs, simultaneously with the air plasma expansion, resulting in the formation of the ring patterns in the case of these modulated laser pulses. These mechanisms are supported by experiments realized in vacuum environment. A model describing the expansion of the heated area by thermal conduction due to plasma free electrons is then presented. Next, the paper deals with the two damage formation phases that are distinguished. The first phase corresponds to the incubation of the laser flux by a subsurface defect until the damage occurrence: an incubation fluence corresponds to this phase. The

  7. SEM and Raman spectroscopy analyses of laser-induced periodic surface structures grown by ethanol-assisted femtosecond laser ablation of chromium

    Science.gov (United States)

    Bashir, Shazia; Shahid Rafique, M.; Nathala, Chandra S. R.; Ajami, Ali; Husinsky, Wolfgang

    2015-05-01

    The effect of fluence and pulse duration on the growth of nanostructures on chromium (Cr) surfaces has been investigated upon irradiation of femtosecond (fs) laser pulses in a liquid confined environment of ethanol. In order to explore the effect of fluence, targets were exposed to 1000 pulses at various peak fluences ranging from 4.7 to 11.8 J cm-2 for pulse duration of ∼25 fs. In order to explore the effect of pulse duration, targets were exposed to fs laser pulses of various pulse durations ranging from 25 to 100 fs, for a constant fluence of 11.8 J cm-2. Surface morphology and structural transformations have been analyzed by scanning electron microscopy and Raman spectroscopy, respectively. After laser irradiation, disordered sputtered surface with intense melting and cracking is obtained at the central ablated areas, which are augmented with increasing laser fluence due to enhanced thermal effects. At the peripheral ablated areas, where local fluence is approximately in the range of 1.4-4 mJ cm-2, very well-defined laser-induced periodic surface structures (LIPSS) with periodicity ranging from 270 to 370 nm along with dot-like structures are formed. As far as the pulse duration is concerned, a significant effect on the surface modification of Cr has been revealed. In the central ablated areas, for the shortest pulse duration (25 fs), only melting has been observed. However, LIPSS with dot-like structures and droplets have been grown for longer pulse durations. The periodicity of LIPSS increases and density of dot-like structures decreases with increasing pulse duration. The chemical and structural modifications of irradiated Cr have been revealed by Raman spectroscopy. It confirms the formation of new bands of chromium oxides and enol complexes or Cr-carbonyl compounds. The peak intensities of identified bands are dependent upon laser fluence and pulse duration.

  8. SEM method for direct visual tracking of nanoscale morphological changes of platinum based electrocatalysts on fixed locations upon electrochemical or thermal treatments.

    Science.gov (United States)

    Zorko, Milena; Jozinović, Barbara; Bele, Marjan; Hodnik, Nejc; Gaberšček, Miran

    2014-05-01

    A general method for tracking morphological surface changes on a nanometer scale with scanning electron microscopy (SEM) is introduced. We exemplify the usefulness of the method by showing consecutive SEM images of an identical location before and after the electrochemical and thermal treatments of platinum-based nanoparticles deposited on a high surface area carbon. Observations reveal an insight into platinum based catalyst degradation occurring during potential cycling treatment. The presence of chloride clearly increases the rate of degradation. At these conditions the dominant degradation mechanism seems to be the platinum dissolution with some subsequent redeposition on the top of the catalyst film. By contrast, at the temperature of 60°C, under potentiostatic conditions some carbon corrosion and particle aggregation was observed. Temperature treatment simulating the annealing step of the synthesis reveals sintering of small platinum based composite aggregates into uniform spherical particles. The method provides a direct proof of induced surface phenomena occurring on a chosen location without the usual statistical uncertainty in usual, random SEM observations across relatively large surface areas.

  9. Morphological architecture of foliar stomata in M2 Carnation (Dianthus caryophyllus L. genotypes using Scanning Electron Microscopy (SEM

    Directory of Open Access Journals (Sweden)

    Rajib Roychowdhury*, Parveen Sultana and Jagatpati Tah

    2011-12-01

    Full Text Available Dianthus caryophyllus is an important floricultural crop in temperate climates and worldwide popular as cut-flowers for itsvariegated petal’s colour. The development of this cultivar with more desirable floral characteristics and higher productivity arealso very much important. Their identifications as well as taxonomy had been studied in the literatures using different laboratorymethods. Both morphological and/or genetical characteristics were considered in the reported studies. However, to the best of ourknowledge, there does not exist any study involving an image analysis based approach. For this, we undertook the mutationbreeding programme with selected chemical mutagens, viz. Colchicine (COL, Ethyl Methane Sulphonate (EMS and MaleicHydrazide (MH with different concentrations. These mutagens were applied on the young leaves of M2 plants of Dianthuscultivar. The results of the present study on peculiar morphological architectures of leaf stomata in Dianthus at differentconcentrations of three potent chemical mutagens were analyzed on the basis of their Scanning Electron Microscopy (SEMimages which is more informative than the classical approach. Number of stomata and its shape, aperture length and itsdimension, characteristics of guard cells in both dorsal and ventral surfaces of leaf also varied from treatment to treatment.

  10. Study of variation in surface morphology, chemical composition, crystallinity and hardness of laser irradiated silver in dry and wet environments

    Science.gov (United States)

    Ali, Nisar; Bashir, Shazia; Umm-i-Kalsoom; Begum, Narjis; Hussain, Tousif

    2017-07-01

    Variation in surface morphology, chemical composition, crystallinity and hardness of laser irradiated silver in dry and wet ambient environments has been investigated. For this purpose, the silver targets were exposed for various number of laser pulses in ambient environment of air, ethanol and de-ionized water for various number of laser pulses i.e. 500, 1000, 1500 and 2000. Scanning Electron Microscope (SEM) was employed to investigate the surface morphology of irradiated silver. SEM analysis reveals significant surface variations for both dry and wet ambient environments. For lower number of pulses, in air environment significant mass removal is observed but in case of ethanol no significant change in surface morphology is observed. In case of de-ionized water small sized cavities are observed with formation of protrusions with spherical top ends. For higher number of laser pulses, refilling of cavities by shock liquefied material, globules and protrusions are observed in case of dry ablation. For ablation in ethanol porous and coarse periodic ripples are observed whereas, for de-ionized water increasing density of protrusions is observed for higher number of pulses. EDS analysis exhibits the variation in chemical composition along with an enhanced diffusion of oxygen under both ambient conditions. The crystal structure of the exposed targets were explored by X-ray Diffraction (XRD) technique. XRD results support the EDS results. Formation of Ag2O in case of air and ethanol whereas, Ag2O and Ag3O in case of de-ionized water confirms the diffusion of oxygen into the silver surface after irradiation. Vickers Hardness tester was employed to measure the hardness of laser treated targets. Enhanced hardness is observed after irradiation in both dry and wet ambient environments. Initial decrease and then increase in hardness is observed with increase in number of laser pulses in air environment. In case of ethanol, increase in number of laser pulses results in

  11. Morphology, thermoelectric properties and wet-chemical doping of laser-sintered germanium nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Stoib, Benedikt; Langmann, Tim; Matich, Sonja; Sachsenhauser, Matthias; Stutzmann, Martin; Brandt, Martin S. [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 4, 85748 Garching (Germany); Petermann, Nils; Wiggers, Hartmut [Institut fuer Verbrennung und Gasdynamik and Center for Nanointegration, Universitaet Duisburg-Essen, Lotharstr. 1, 47048 Duisburg (Germany)

    2013-01-15

    Porous, highly doped semiconductors are potential candidates for thermoelectric energy conversion elements. We report on the fabrication of thin films of Ge via short-pulse laser-sintering of Ge nanoparticles (NPs) in vacuum and study the macroporous morphology of the samples by secondary electron microscopy (SEM) imaging. The temperature dependence of the electrical conductivity and the Seebeck coefficient of undoped Ge is discussed in conjunction with the formation of a defect band near the valence band. We further introduce a versatile method of doping the resulting films with a variety of common dopant elements in group-IV semiconductors by using a liquid containing the dopant atoms. This method is fully compatible with laser-direct writing and suited to fabricate small scale thermoelectric generators. The incorporation of the dopants is verified by X-ray photoelectron spectroscopy (XPS) and their electrical activation is studied by conductivity and thermopower measurements. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Composite filling removal with erbium:yttrium-aluminum-garnet laser: morphological analyses.

    Science.gov (United States)

    Correa-Afonso, Alessandra M; Palma-Dibb, Regina G; Pécora, Jesus Djalma

    2010-01-01

    Considering the increase in esthetic restorative materials and need for improvement in unsatisfactory restoration substitution with minimal inadvertent removal of healthy tissues, this study assessed the efficacy of erbium:yttrium-aluminum-garnet (Er:YAG) laser for composite resin removal and the influence of pulse repetition rate on the morphological analyses of the cavity by scanning electron microscope. Composite resin fillings were placed in cavities (1.0 mm deep) prepared in bovine teeth, and the 75 specimens were randomly assigned to five groups according to the technique used for composite filling removal (high-speed diamond bur, group I, as a control, and Er:YAG laser, 250 mJ output energy and 80 J/cm(2) energy density, using different pulse repetition rates: group II, 2 Hz; group III, 4 Hz; group IV, 6 Hz; group V, 10 Hz). After the removal, the specimens were split in the middle, and we analyzed the surrounding and deep walls to check for the presence of restorative material. The estimation was qualitative. The surfaces were examined with a scanning electron microscope. The results revealed that the experimental groups presented bigger amounts of remaining restorative material. The scanning electron microscopy (SEM) analyses showed irregularities of the resultant cavities of the experimental groups that increased proportionally with increase in repetition rate.

  13. Low-power pulsed Nd:YAG laser irradiation for pre-emptive anaesthesia: A morphological and histological study.

    Science.gov (United States)

    Chan, Ambrose; Punnia-Moorthy, Arumugam; Armati, Patricia

    2014-12-27

    To determine if tooth structure or dental pulp of normal healthy human premolar teeth to be extracted for orthodontic reasons exhibit morphological or histological changes following dental anaesthesia by pulsed Nd:YAG laser and subsequent cavity preparation (CP). Materials (Subjects) and Methods: 54 bilateral paired of human, healthy premolar teeth identified for inclusion in a clinical trial of Nd:YAG-induced anaesthesia and subsequently extracted for orthodontic reasons, were randomly divided into 4 treatment groups: Group 1 - teeth (n=44) were irradiated with 150 µs pulsed Nd:YAG laser-1064 nm (American Dental Laser, dLase300, Sunrise Technologies Inc., Folsom, CA, USA; Average power: 1.1 ± 0.2 W, power density: 39+ 0.7 W/cm(2), area 0.28 cm(2), 15 Hz; energy density:0. 260+ 0.047 J/cm(2)) +Sham EMLA (cream without active component) followed by cavity preparation (CP); Group 2 - Teeth (n=44) - were treated with EMLA + Sham Laser (1 mW 632.8-nm He:Ne laser aiming beam only) with CP; Group 3 Teeth (n=10) - were irradiated with pulsed Nd:YAG laser as above but minus CP; Group 4 (n=10)- was a Control group with teeth untreated (no Laser, EMLA or CP). Clinical anaesthesia was assessed by electric pulp testing (EPT) and CP. Teeth in each of the 4 groups were processed for examination by i) scanning electron microscopy (SEM); ii) longitudinal undecalcified ground sectioning (LUGS); iii) light microscopy of pulpal tissues or iv) dye penetration. Both Laser and EMLA groups demonstrated no alteration to mineralized tooth structure and dentinal permeability. Mild superficial pulpal changes were found in both groups (3/18 teeth) and of no statistical difference (p>0.99, the McNemar test). Neither Laser nor the Control groups minus CP, showed pulpal changes. Low-power pulsed Nd:YAG laser dose, as used in the clinical trial to induce anaesthesia, does not cause morphological damage to the mineralized tooth structure. Both Laser and EMLA groups showed minor superficial

  14. Irradiation effects of CO2 laser parameters on surface morphology of fused silica

    Institute of Scientific and Technical Information of China (English)

    Xiang Xia; Zheng Wan-Guo; Yuan Xiao-Dong; Dai Wei; Juang Yong; Li Xi-Bin; Wang Hai-Jun; Lü Hai-Bing; Zu Xiao-Tao

    2011-01-01

    To understand the surface morphology evolution of fused silica induced by 10.6-prn CO2 laser irradiation atdifferent parameters, this paper reports that optical microscopy, profilometry, and hydrophilicity tests are utilized to characterize the surface structure and roughness of the laser irradiated area. The results show that three typical surface morphologies and two typical by drophilicity test images are observed at different laser powers and pulse durations. Thecorrelations between surface temperature and surface morphology as well as hydrophilicity behaviours are presented.The different hydrophilicity behaviours are related to surface structures of the laser-induced crater and thermal diffusion area. The thermal diffusion length monotonously increases with increasing laser power and pulse duration. The crater width is almost determined by the laser beam size. The crater depth is more sensitive to the laser power and pulse duration than the crater width.

  15. Morphological Characterization of ALD and Doping Effects on Mesoporous SnO2 Aerogels by XPS and Quantitative SEM Image Analysis.

    Science.gov (United States)

    Correa-Baena, Juan-Pablo; Artyushkova, Kateryna; Santoro, Carlo; Atanassov, Plamen; Agrios, Alexander G

    2016-04-20

    Atomic layer deposition (ALD) is unsurpassed in its ability to create thin conformal coatings over very rough and/or porous materials. Yet although the coating thickness on flat surfaces can be measured by ellipsometry, characterization of these coatings on rough surfaces is difficult. Here, two techniques are demonstrated to provide such characterization of ALD-coated TiO2 over mesoporous SnO2 aerogel films on glass substrates, and insights are gained as to the ALD process. First, X-ray photoelectron spectroscopy (XPS) is used to determine the coating thickness over the aerogel, and the results (0.04 nm/cycle) agree well with ellipsometry on flat surfaces up to a coating thickness limit of about 6 nm. Second, quantitative analysis of SEM images of the aerogel cross section is used to determine porosity and roughness, from which coating thickness can be inferred. The analysis reveals increasing porosity from the aerogel/air interface to the aerogel/substrate interface, indicating a thicker ALD coating near the air side, which is consistent with tortuous diffusion through the pores limiting access of ALD precursors to deeper parts of the film. SEM-derived porosity is generally useful in a thin film because bulk methods like nitrogen physisorption or mercury porosimetry are impractical for use with thin-film samples. Therefore, in this study SEM was also used to characterize quantitatively the morphologogical changes in SnO2 aerogel thin films due to doping with Sb. This study can be used as a methodology to understand morphological changes in different types of porous and/or rough materials.

  16. New insights to pore space morphologies in Boom Clay - results from 2D BIB-SEM investigations and mercury injection porosimetry

    Science.gov (United States)

    Hemes, S.; Desbois, G.; Urai, J. L.

    2012-04-01

    BIB-SEM investigations on Boom Clay (Mol-Dessel reference site for radioactive waste disposal, Belgium) of different grain sizes yield new insights to pore space morphologies and pore-size distributions down to the resolution of state-of-the-art SEM. Non-clay minerals embedded into a clay matrix form the overall fabric of the different samples investigated. We identified four main porous mineral phases: clay, pyrite, mica and fossils. Regardless of the origin and the grain-size distribution of samples, characteristic pore morphologies were found for each different mineral phase. Our approach allows segmenting pores with a practical pore resolution of 25-30 nm in pore size (equivalent radius, ER) resulting in total porosities of 10-20 % and log-normal pore-size distributions at the scale of observation. Detailed studies of segmented porosities within the clay matrices point to a power-law distribution of pore-areas over three orders of magnitude, interpreted as self-similarity of the pore space. Moreover, two classes of pore-sizes were distinguished within the clay-matrix: biggest pores were found within the first 100 nm from non-clay mineral grain-boundaries, whereas pores smaller than 100 nm (ER) are homogeneously distributed within the clay matrix. Our calculations show clearly that the median pore-size value of the biggest pores is linked to the grain size parameter, which suggests that the grain- size and the amount of non-clay minerals is controlling the contribution of the largest pore-size fraction to the overall porosity. Bulk porosities measured by mercury injection porosimetry (MIP) are between 26-33 %. The comparison of our microstructural investigations inferred by BIB-SEM with MIP data, indicates that a significant pore fraction is not detected by using the BIB-SEM method (about 10-15 % of the total porosity), corresponding to pores smaller than 30 nm (ER). However, the extrapolation of power-law pore-size distributions, inferred for pores within the

  17. Superpulsed low-level laser therapy protects skeletal muscle of mdx mice against damage, inflammation and morphological changes delaying dystrophy progression.

    Directory of Open Access Journals (Sweden)

    Ernesto Cesar Pinto Leal-Junior

    Full Text Available AIM: To evaluate the effects of preventive treatment with low-level laser therapy (LLLT on progression of dystrophy in mdx mice. METHODS: Ten animals were randomly divided into 2 experimental groups treated with superpulsed LLLT (904 nm, 15 mW, 700 Hz, 1 J or placebo-LLLT at one point overlying the tibialis anterior muscle (bilaterally 5 times per week for 14 weeks (from 6th to 20th week of age. Morphological changes, creatine kinase (CK activity and mRNA gene expression were assessed in animals at 20th week of age. RESULTS: Animals treated with LLLT showed very few morphological changes in skeletal muscle, with less atrophy and fibrosis than animals treated with placebo-LLLT. CK was significantly lower (p=0.0203 in animals treated with LLLT (864.70 U.l-1, SEM 226.10 than placebo (1708.00 U.l-1, SEM 184.60. mRNA gene expression of inflammatory markers was significantly decreased by treatment with LLLT (p<0.05: TNF-α (placebo-control=0.51 µg/µl [SEM 0.12], - LLLT=0.048 µg/µl [SEM 0.01], IL-1β (placebo-control=2.292 µg/µl [SEM 0.74], - LLLT=0.12 µg/µl [SEM 0.03], IL-6 (placebo-control=3.946 µg/µl [SEM 0.98], - LLLT=0.854 µg/µl [SEM 0.33], IL-10 (placebo-control=1.116 µg/µl [SEM 0.22], - LLLT=0.352 µg/µl [SEM 0.15], and COX-2 (placebo-control=4.984 µg/µl [SEM 1.18], LLLT=1.470 µg/µl [SEM 0.73]. CONCLUSION: Irradiation of superpulsed LLLT on successive days five times per week for 14 weeks decreased morphological changes, skeletal muscle damage and inflammation in mdx mice. This indicates that LLLT has potential to decrease progression of Duchenne muscular dystrophy.

  18. Enhanced Photocatalytic Performance Depending on Morphology of Bismuth Vanadate Thin Film Synthesized by Pulsed Laser Deposition.

    Science.gov (United States)

    Jeong, Sang Yun; Choi, Kyoung Soon; Shin, Hye-Min; Kim, Taemin Ludvic; Song, Jaesun; Yoon, Sejun; Jang, Ho Won; Yoon, Myung-Han; Jeon, Cheolho; Lee, Jouhahn; Lee, Sanghan

    2017-01-11

    We have fabricated high quality bismuth vanadate (BiVO4) polycrystalline thin films as photoanodes by pulsed laser deposition (PLD) without a postannealing process. The structure of the grown films is the photocatalytically active phase of scheelite-monoclinic BiVO4 which was obtained by X-ray diffraction (XRD) analysis. The change of surface morphology for the BIVO4 thin films depending on growth temperature during synthesis has been observed by scanning electron microscopy (SEM), and its influence on water splitting performance was investigated. The current density of the BiVO4 film grown on a glass substrate covered with fluorine-doped tin oxide (FTO) at 230 °C was as high as 3.0 mA/cm(2) at 1.23 V versus the potential of the reversible hydrogen electrode (VRHE) under AM 1.5G illumination, which is the highest value so far in previously reported BiVO4 films grown by physical vapor deposition (PVD) methods. We expect that doping of transition metal or decoration of oxygen evolution catalyst (OEC) in our BiVO4 film might further enhance the performance.

  19. Morphologic Changes of Zebrafish Melanophore after Intense Pulsed Light and Q-Switched Nd:YAG Laser Irradiation

    Science.gov (United States)

    Ryu, Hwa Jung; Lee, Ji Min; Jang, Hee Won; Park, Hae Chul; Rhyu, Im Joo

    2016-01-01

    Background Recently, the pulse-in-pulse mode of intense pulsed light (IPL) has been used increasingly for the treatment of melasma. Objective To observe the morphologic changes in the melanophore in adult zebrafish after irradiation with conventional and pulse-in-pulse IPL and Q-switched Nd:YAG (QSNY) laser. Methods Adult zebrafish were irradiated with conventional and pulse-in-pulse mode of IPL. The conditions for conventional IPL were 3 mJ/cm2, 560 nm filter, and pulse widths of 7, 20, and 35 msec. The pulse-in-pulse conditions were 3 mJ/cm2 and on-time 1/off-time 2. The QSNY laser was used with the settings of 1,064 nm, 0.4 J/cm2, a 7 mm spot size, and one shot. Specimens were observed using a light microscope, a transmission electron microscope (TEM), a scanning electron microscope (SEM) and a confocal microscope. Results After conventional IPL irradiation with a 7 msec pulse width, melanophore breakage was observed using light microscopy. Under TEM, irradiation with conventional IPL for 7 msec and pulse-in-pulse IPL induced melanophore thermolysis with vacuolization. However, changes in the melanophore were not observed with 35 msec IPL. Under SEM, unlike the control and QSNY groups, IPL-irradiated zebrafish showed finger-like fusion in the protein structure of scales. Specimens examined by a confocal microscope after conventional IPL irradiation showed a larger green-stained area on TUNEL staining than that after pulse-in-pulse mode IPL irradiation. Conclusion Zebrafish irradiated with long pulse-IPL showed no morphologic changes using light microscopy, while morphological changes in melanophores were evident with use of TEM. Pulse-in-pulse mode IPL caused less damage than conventional IPL. PMID:27904270

  20. Characterization of the Morphology of RDX Particles Formed by Laser Ablation

    Science.gov (United States)

    2012-02-01

    laser-ablated particle sizes. ...................4 Figure 3. SEM images of laser-ablated M43 propellant grain at (a) 150× magnification and (b) 500...Experimental Method 2.1 Materials The energetic materials studied included an M43 propellant grain that consists of ~76% RDX, 12% cellulose acetate...butyrate (CAB), 8% plasticizer, and 4% nitrocellulose (NC) (26). Class-1 ( m) and class-5 (ឝ m) military-grade and research-grade (i.e

  1. Microhardness and morphological changes induced by Nd:Yag laser on dental enamel: an in vitro study.

    Science.gov (United States)

    Bedini, Rossella; Manzon, Licia; Fratto, Giovanni; Pecci, Raffaella

    2010-01-01

    The aim of this work was a scanning electron microscopy (SEM) evaluation of the hardness and morphological changes of enamel irradiated by neodymium: yttrium aluminium garnet (Nd:YAG) laser with different energy levels. Twenty-eight human teeth samples were divided into 4 groups: control, where enamel surface was not lased, and 3 test treated with 3 different levels of energy power 0.6, 1.2 and 2.4 Watt, respectively. In each group, 5 samples underwent Vickers micro-hardness test and 2 samples were processed for SEM. No significant differences between treated and non treated samples were found by micro-hardness test. However, by SEM, test samples showed a rougher enamel surface than control. Specifically, the 0.6 Watt treated samples showed vertical scratches and glass-like areas, while in the other 2 groups enamel surface was covered by craters and cracks. These findings suggest that enamel should be lased at a low energy level to preserve its integrity and reduce demineralization, and thus for dental caries prevention purposes; while high energy level creates a retentive surface suitable for sealant or composite anchorage.

  2. Wavelength effect on hole shapes and morphology evolution during ablation by picosecond laser pulses

    Science.gov (United States)

    Zhao, Wanqin; Wang, Wenjun; Li, Ben Q.; Jiang, Gedong; Mei, Xuesong

    2016-10-01

    An experimental study is presented of the effect of wavelength on the shape and morphology evolution of micro holes ablated on stainless steel surface by a 10 ps Q-switched Nd:VAN pulsed laser. Two routes of hole development are associated with the visible (532 nm) and near-infrared (1064 nm) laser beams, respectively. The evolution of various geometric shapes and morphological characteristics of the micro holes ablated with the two different wavelengths is comparatively studied for other given processing conditions such as a laser power levels and the number of pulses applied. Plausible explanations, based on the light-materials interaction associated with laser micromachining, are also provided for the discernable paths of geometric and morphological development of holes under laser ablation.

  3. Scanning electron microscopy (SEM) and X-ray dispersive spectrometry evaluation of direct laser metal sintering surface and human bone interface: a case series.

    Science.gov (United States)

    Mangano, Carlo; Piattelli, Adriano; Raspanti, Mario; Mangano, Francesco; Cassoni, Alessandra; Iezzi, Giovanna; Shibli, Jamil Awad

    2011-01-01

    Recent studies have shown that direct laser metal sintering (DLMS) produces structures with complex geometry and consequently that allow better osteoconductive properties. The aim of this patient report was to evaluate the early bone response to DLMS implant surface retrieved from human jaws. Four experimental DLMS implants were inserted in the posterior mandible of four patients during conventional dental implant surgery. After 8 weeks, the micro-implants and the surrounding tissue were removed and prepared for scanning electron microscopy (SEM) and histomorphometric analysis to evaluate the bone-implant interface. The SEM and EDX evaluations showed a newly formed tissue composed of calcium and phosphorus. The bone-to-implant contact presented a mean of 60.5 ± 11.6%. Within the limits of this patient report, data suggest that the DLMS surfaces presented a close contact with the human bone after a healing period of 8 weeks.

  4. Micro- and nanosecond laser TiN coating/steel modification: Morphology studies

    Science.gov (United States)

    Trtica, M.; Tarasenko, V. F.; Gaković, B.; Panchenko, A. N.; Radak, B.; Stasić, J.

    2009-09-01

    Morphology effects induced during interaction of μs- (Transversely Excited Atmospheric (TEA) CO2 laser) or ns- (HF laser) pulses with titanium nitride (TiN) coating, deposited on austenitic stainless steel AISI 316, were studied. Experiments were carried out in regime of focused laser beam in air at atmospheric pressure. The used laser fluences were found to be sufficient for inducing intensive surface modifications of the target. The energy absorbed from the CO2 as well as HF laser beam is mainly converted into thermal energy, causing different effects like ablation, appearance of hydrodynamic features, etc. Morphology characteristics obtained during ns-pulses irradiation (HF laser) were different to those initiated by μs-pulses (TEA CO2 laser). The changes on the target surface in form of massive resolidifed droplets and crown-like structures were observed only for ns- (HF laser) pulses. It was found that these effects are a consequence of higher temperature and better coupling of the HF laser radiation with the target. Recent investigations of ps-Nd:YAG laser interaction with the same TiN coating showed that morphology picture is quite different including the reduction of thermal effect.

  5. Dichromatic and monochromatic laser radiation effects on survival and morphology of Pantoea agglomerans

    Science.gov (United States)

    Thomé, A. M. C.; Souza, B. P.; Mendes, J. P. M.; Soares, L. C.; Trajano, E. T. L.; Fonseca, A. S.

    2017-05-01

    Despite the beneficial effects of low-level lasers on wound healing, their application for treatment of infected injuries is controversial because low-level lasers could stimulate bacterial growth exacerbating the infectious process. Thus, the aim of this work was to evaluate in vitro effects of low-level lasers on survival, morphology and cell aggregation of Pantoea agglomerans. P. agglomerans samples were isolated from human pressure injuries and cultures were exposed to low-level monochromatic and simultaneous dichromatic laser radiation to study the survival, cell aggregation, filamentation and morphology of bacterial cells in exponential and stationary growth phases. Fluence, wavelength and emission mode were those used in therapeutic protocols for wound healing. Data show no changes in morphology and cell aggregation, but dichromatic laser radiation decreased bacterial survival in exponential growth phase and monochromatic red and infrared lasers increased bacterial survival at the same fluence. Simultaneous dichromatic laser radiation induces biological effects that differ from those induced by monochromatic laser radiation and simultaneous dichromatic laser could be the option for treatment of infected pressure injuries by Pantoea agglomerans.

  6. Surface morphological changes on the human dental enamel and cement after the Er:YAG laser irradiation at different incidence angles; Avaliacao morfologica das superficies do esmalte e do cimento dental apos a irradiacao do laser de Er:YAG em diferentes angulacoes

    Energy Technology Data Exchange (ETDEWEB)

    Tannous, Jose Trancoso

    2001-07-01

    This is a morphological analysis study through SEM of the differences of the laser tissue interaction as a function of the laser beam irradiation angle, under different parameters of energy. Fourteen freshly extracted molars stored in a 0,9% sodium chloride solution were divided in seven pairs and were irradiated with 100, 200, 300, 400, 500, 600 and 700 mJ per pulse, respectively. Each sample received three enamel irradiations and three cement irradiations, either in the punctual or in the contact mode, one near to the other, with respectively 30, 45 and 90 inclinations degrees of dental surface-laser-beam incidence. Four Er:YAG pulses (2,94 {mu}m, 7-20 Hz, 0,1-1 J energy/pulse - Opus 20 - Opus Dent) with water cooling system (0,4 ml/s) were applied. After the laser irradiation the specimens were analysed through scanning electron microscope (SEM). The results were analysed by SEM micrographs showing a great difference on the laser tissue interaction characteristics as a function of the irradiation angle of the laser beam. All the observations led to conclude that, considering the laser parameters used, the incidence angle variation is a very important parameter regarding the desired morphological effects. This represents an extremely relevant detail on the technical description of the Er:YAG laser irradiation protocols on dental tissues. (author)

  7. Chemical and morphological characterization of TSP and PM2.5 by SEM-EDS, XPS and XRD collected in the metropolitan area of Monterrey, Mexico

    Science.gov (United States)

    González, Lucy T.; Rodríguez, F. E. Longoria; Sánchez-Domínguez, M.; Leyva-Porras, C.; Silva-Vidaurri, L. G.; Acuna-Askar, Karim; Kharisov, B. I.; Villarreal Chiu, J. F.; Alfaro Barbosa, J. M.

    2016-10-01

    Total suspended particles (TSP) and particles smaller than 2.5 μm (PM2.5) were collected at four sites in the metropolitan area of Monterrey (MAM) in Mexico. The samples were characterized by X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), and Scanning Electron Microscopy (SEM). In order to determine the possible sources of emissions of atmospheric particulate matter, a principal component analysis (PCA) was performed. The XRD results showed that the major crystalline compounds found in the TPS were CaCO3 and SiO2; while in the PM2.5 CaSO4 was found. The XPS analysis showed that the main elements found on the surface of the particles were C, O, Si, Ca, S, and N. The deconvolution carried out on the high-resolution spectra for C1s, S2p and N1s, showed that the aromatics, sulfates and pyrrolic-amides were the main groups contributing to the signal of these elements, respectively. The C-rich particles presented a spherical morphology, while the Ca- and Si-based particles mostly showed a prismatic shape. The PCA analysis together with the results obtained from the characterization techniques, suggested that the main contributors to the CaCO3 particles collected in the PM were most probably produced and emitted into the atmosphere by local construction industries and exploitation of rich-deposits of calcite. Meanwhile, the SiO2 found in the MAM originated from the suspension of geological material abundant in the region, and the carbon particles were mainly produced by the combustion of fossil fuels.

  8. 扫描电镜/能谱法检验激光打印文件%Discrimination of Laser Printing Documents by SEM/EDX

    Institute of Scientific and Technical Information of China (English)

    王晓宾; 黄建同

    2015-01-01

    目的:应用扫描电镜/能谱法检验不同品牌和型号激光打印机的打印文件,实现对不同机型打印文件的区分。方法收集不同品牌和型号激光打印机10台,利用扫描电镜/能谱仪对相同的打印字符进行无机元素分析,获得样品的能谱图和mapping分析图,对样品进行定量和半定性分析;同时收集10个不同品牌的A4静电复印纸,分析纸张对实验结果的影响。结果依据所含元素的种类可以将10台激光打印机分为四类;依据主要元素相对百分含量的比值,对不同品牌和型号激光打印文件进行区分;研究结果表明纸张因素对定性结果影响较小,对定量结果影响较大。结论扫描电镜/能谱法可以简单、快速、无损的区分和识别激光打印文件,可以应用于二次打印文件的检验,为侦查破案提供线索。%ABSTRACT:ObjectiveThis paper aims to distinguish documents printed with different brands and models of laser printer using scanning electron microscopy with energy dispersive X-ray (SEM/EDX).MethodsDocuments printed with 10 brands and models of laser printers were collected, and SEM/EDX was used to analyze the inorganic elements of characters on the documents. Each sample was tested three times and energy spectra and mapping analysis charts were obtained. Qualitative and semi-quantitative analyses were also conducted and the elemental components and their distribution in ink of printing characters were determined. In order to analyze the inlfuence of paper, 10 brands of A4 xerographic papers were collected and elements were analyzed on the blank area.Results10 brands and models of laser printers were divided into 4 categories according to element C, O, Na, Al, Si, Cl, Ca, and Fe detected from the printing characters. The ratio of C/O and Ca/C of laser printing characters were calculated to distinguish the brands and models of laser printer in the same category. The analysis of A4

  9. Evaluation of fibroblast attachment in root conditioning with Er, Cr:YSGG laser versus EDTA: a SEM study.

    Science.gov (United States)

    Fekrazad, Reza; Lotfi, Ghogha; Harandi, Mohammad; Ayremlou, Sara; Kalhori, Katayoun A M

    2015-04-01

    The regeneration of periodontal support is a main concern in periodontal therapy. This study aims to investigate the efficacy of Er, Cr:YSGG laser and EDTA based conditioning in attachment of fibroblast on root surfaces. This in vitro study was conducted on 81 root plates (6 mm × 4 mm × 1 mm) prepared from 27 single-rooted human mature teeth. The samples were divided into three groups: (1) Er, Cr: YSGG laser conditioning with a G6 tip (2.78 µm, 0.75 W, pulse duration of 140 µs, repetition rate of 20 Hz) for 5-7 s; (2) EDTA conditioning (17%, pH: 8) for 1 min; and (3) the control group which were exposed neither to EDTA nor laser. The viability and proliferation rates assessments were performed using MTT assay on days 3 and 5. In addition, the level of cell attachment was studied using scanning electron microscopy. The data indicated Er, Cr:YSGG conditioning increased cell viability by lapse of time (from days 3-5), with significantly better cell attachment compared to the other groups on days 3 and 5 (P EDTA conditioning group compared with the control group was statistically significant on day 5 but not on day 3 (P EDTA.

  10. Effect of Er,Cr:YSGG and Er:YAG laser irradiation on the adhesion of blood components on the root surface and on root morphology.

    Science.gov (United States)

    Oliveira, Guilherme José Pimentel Lopes de; Theodoro, Letícia Helena; Marcantonio Junior, Elcio; Sampaio, José Eduardo Cezar; Marcantonio, Rosemary Adriana Chiérici

    2012-01-01

    The aim of this study was to conduct an in vitro evaluation, by scanning electron microscopy (SEM), of the adhesion of blood components on root surfaces irradiated with Er,Cr:YSGG (2.78 µm) or Er:YAG (2.94 µm) laser, and of the irradiation effects on root surface morphology. Sixty samples of human teeth were previously scaled with manual instruments and divided into three groups of 20 samples each: G1 (control group) - no treatment; G2 - Er,Cr:YSGG laser irradiation; G3 - Er:YAG laser irradiation. After performing these treatments, blood tissue was applied to 10 samples of each group, whereas 10 samples received no blood tissue application. After performing the laboratory treatments, the samples were observed under SEM, and the resulting photomicrographs were classified according to a blood component adhesion scoring system and root morphology. The results were analyzed statistically (Kruskall-Wallis and Mann Whitney tests, α= 5%). The root surfaces irradiated with Er:YAG and Er,Cr:YSGG lasers presented greater roughness than those in the control group. Regarding blood component adhesion, the results showed a lower degree of adhesion in G2 than in G1 and G3 (G1 × G2: p = 0.002; G3 × G2: p = 0.017). The Er:YAG and Er,Cr:YSGG laser treatments caused more extensive root surface changes. The Er:YAG laser treatment promoted a greater degree of blood component adhesion to root surfaces, compared to the Er,Cr:YSGG treatment.

  11. Corneal morphology after ex-vivo UV and mid-infrared laser ablation

    Science.gov (United States)

    Spyratou, E.; Voloudakis, G. E.; Moutsouris, K.; Asproudis, I.; Baltatzis, S.; Makropoulou, M.; Bacharis, C.; Serafetinides, A. A.

    2008-12-01

    In this work, ablation experiments of ex vivo porcine cornea tissue were conducted with two solid state lasers (an Er:YAG laser and the 4th harmonic of an Nd:YAG laser, both in the ns pulse width range) emitting in mid infrared and ultraviolet part of the spectrum respectively, at moderate laser fluences. The cornea epithelium of each porcine eye was manually removed before the ablation. Histology analysis of the specimens was performed, in order to examine the microscopic appearance of the ablated craters and the existence of any thermal or mechanical damage caused by the midinfrared and the UV laser irradiation. For a detailed and complete examination of the morphology of the laser ablated corneal tissue, the surface roughness was investigated by scanning electron microscopy.

  12. Morphological alterations on Citrobacter freundii bacteria induced by erythrosine dye and laser light.

    Science.gov (United States)

    Silva, Josmary R; Cardoso, Gleidson; Maciel, Rafael R G; de Souza, Nara C

    2015-01-01

    The effect of the laser irradiation (532 nm) on films prepared from Citrobacter freundii mixed with erythrosine dye was investigated by using atomic force microscopy. It was observed that morphological changes of bacterial surfaces after irradiations, which were attributed to cellular damage of the outer membranes, are a result of a photodynamic effect. The results suggested that the combination of erythrosine and laser light at 532 nm could be a candidate to a photodynamic therapy against C. freundii.

  13. Morphological Study Of Border Area Of Pulp-Capping Materials And Er:YAG Laser Prepared Hard Dental Surface.

    Science.gov (United States)

    Stefanova, Vessela P; Tomov, Georgi T; Tsanova, Snezhana Ts

    2015-01-01

    Vital pulp therapy involves biologically based therapeutic activities aimed at restoring health and preserving the vitality of cariously or traumatically damaged pulp. Adaptation of pulp-capping materials to the prepared tooth surface may be the key to the success of biological tooth treatment. To investigate the area of adaptation of synthetic tricalcium silicate cement, calcium hydroxide cement and mineral trioxide-aggregate to the dentin surface, prepared with the help of Er:YAG dental laser. Four extracted human tooth cavities were prepared with the help of Er:YAG dental laser (LiteTouch, Syneron, Israel), establishing microcommunication with the pulp chamber less than 1 mm in diameter. As pulp-capping materials in the cavities we used tricalcium silicate cement (Biodentine, Septodont, France), calcium hydroxide cement (Dycal) and mineral-trioxide aggregate (ProRoot MTA), stirred and administered according to manufacturers' instructions. The first material fills the whole cavity and the other two are spread in a thin layer and sealed with glass ionomer cement. Thus prepared, the samples were left for three days at 37°C in humidified environment. The samples were prepared for scanning electron microscopy (SEM) by standard methodology. The border area surfaces of the materials and the dentin were scanned using electron microscopy. The morphological changes occurring to the Er:YAG laser prepared dentin and the structural characteristics of the studied pulp-capping materials are demonstrated using scanograms. The border areas where good contact of materials and dentinal tubules is established are thoroughly studied. Good adaptation is seen in three-calcium silicate cement, followed by mineral trioxide aggregate and calcium hydroxide cement. The dentin surface, prepared with Er:YAG laser demonstrates a very good adaptation of the three tested pulp-capping materials.

  14. Ion beam and complementary SEM and XRD characterization of YBa{sub 2}Cu{sub 3}O{sub 7-x} films obtained by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Branescu, Maria [National Institute for R and D of Materials Physics, 105 bis Atomistilor Street, P.O. Box MG-7, 077125 Bucharest-Magurele (Romania)]. E-mail: maria_branescu@yahoo.com; Thome, L. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, 91406 Orsay Cedex (France); Pantelica, D. [' Horia Hulubei' National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest (Romania); Ward, I. [CEA, 810 Kifer Road, Sunnyvale, CA 94086 (United States); Vailionis, A. [Stanford University, Stanford, CA 94305 (United States); Ionescu, P. [' Horia Hulubei' National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest (Romania)

    2006-08-15

    We report two ion beam analysis techniques, elastic recoil detection analysis (ERDA) and Rutherford backscattering (RBS), to characterize YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) films, obtained in situ by pulsed laser deposition (PLD). Initially, ERDA measurements were performed on a thin film to evaluate the PLD rate. RBS measurements correlated with complementary scanning electron microscopy and X-ray diffraction measurements were performed afterwards on a good quality thick YBCO film to determine its stoichiometry, thickness, crystalline structure and surface morphology.

  15. Corneal surface morphology following excimer laser ablation with humidified gases.

    Science.gov (United States)

    Krueger, R R; Campos, M; Wang, X W; Lee, M; McDonnell, P J

    1993-08-01

    To compare the effects of blowing dry (nitrogen or helium) and humidified gases over the corneal surface during photorefractive keratectomy. Excimer laser myopic ablations were performed on porcine eyes (10 per group) using humidified and dry nitrogen and helium gas under ambient conditions. Surface smoothness was quantified with light and electron microscopy. Corneas that were ablated using humidified gas were smooth and equivalent to those ablated under ambient conditions. Dry nitrogen and helium blowing resulted in increased surface irregularity evident on light and electron microscopy (P excimer laser corneal ablation produces a smoother surface than does the blowing of dry gas and is comparable to that produced under ambient (no blowing) conditions. Maintaining corneal moisture is important in photorefractive keratectomy. If blowing gas is necessary to remove debris from the surface, the gas should be humidified.

  16. A fast method for morphological analysis of laser drilling holes

    OpenAIRE

    Schneider, Matthieu; Berthe, Laurent; Muller, Maryse; Fabbro, Rémy

    2010-01-01

    International audience; This paper presents an original method for analyzing laser drilled holes. The so-called Direct Observation of Drilled hOle (DODO) method is introduced and its applications. The hole characterization that's been made is compared with x-ray radiography and cross-section analysis. Direct Observation of Drilled hole provides instantaneously surface state, geometric shape, as well as recast layer structure, without additional operation. Since no mounting resin is used to em...

  17. Influence of USP laser radiation on cell morphology: HaCat and MG-63 cell lines for bone and soft tissue modelling in dentistry

    Science.gov (United States)

    Meister, Joerg; Schelle, Florian; Beier, Imke; Bourauel, Christoph; Frentzen, Matthias; Kraus, Dominik

    Due to the high intensities of USP laser radiation, the interaction with matter is always attended with a plasma formation. Therefore the surrounding tissue can be influenced by heat generation and additional light emission from the UV up to the near and mid infrared. In dentistry it is of importance that the treatment of bone and soft tissues, i.e. oral mucosa, with a USP laser should not cause any kind of morphological changes on the cell level leading to a delayed wound healing or cell mutation. HaCaT keratinocyte cells were used for epidermal (soft tissue) and MG-63 osteoblast-like cells for hard tissue (bone) modelling. Cell growing was realized on glas cover slips. Irradiation was carried out with a USP Nd:YVO4 laser having a center wavelength at 1064 nm. Based on the pulse duration of 8 ps and a pulse repetition rate of 500 kHz the laser emits an average power of 9 W. For efficiency testing of cell removal on glas cover slips, 1, 5, 25, 50 and 75 repetitions of the scanning pattern (scan loops) were used. Heat distribution during laser irradiation was measured with an infrared camera system. Subsequently haematoxylin staining and SEM investigations were used to analyse the morphological changes. Differences of cell removal efficiency were observed with repetitions =50 were cell-free. Additionally, repetitions >=25 showed side effects for both cell lines. Cell destruction in both cell lines could be verified using the haematoxylin staining and the SEM pictures.

  18. Composition, XRD and morphology study of laser prepared LiNbO3 films

    Science.gov (United States)

    Jelínek, M.; Havránek, V.; Remsa, J.; Kocourek, T.; Vincze, A.; Bruncko, J.; Studnička, V.; Rubešová, K.

    2013-03-01

    LiNbO3 films were deposited by PLD from LiNbO3 crystalline or from three different stoichiometric or Li-enriched LiNbO3 targets. Polycrystalline films were prepared on SiO2/Si or sapphire substrates at temperatures T S ˜650-750 °C. Main attention was paid to the influence of targets preparation and the deposition conditions on films composition, morphology and crystallinity. The thin-film morphology was determined by SEM microscopy. The composition was measured by SIMS, RBS, PIXE and PIGE methods. Highly oriented, smooth and stoichiometric LiNbO3 films were synthesized.

  19. Evaluation of the morphological alteration of the root surface radiated with a diode laser; Avaliacao da alteracao morfologica da superficie cimentaria irradiada com laser de diodo

    Energy Technology Data Exchange (ETDEWEB)

    Gulin, Mauricio

    2003-07-01

    The diode laser has been studied for periodontal therapy, as much for removal of calculus as for microbial reduction of periodontal pockets, as well as the visible analgesic effects and biomodulation capacity. For this reason the purpose of this study was to evaluate the morphological alteration of the root surface after radiation with the diode laser, 808 nm through analysis by scanning electron microscopy (SEM). Besides this, to verify the temperature variations caused during the radiation, a thermometer put into the dentinal wall of the root canal was used. In all, 18 teeth were used, 15 of which for the SEM study, and the other 3 were used to temperature variation analysis. The 25 samples were scraped on the root surface and planed with manual instruments. The other 5 were not subjected to any type of treatment. This, 6 groups of 5 samples each were formed. Control Group C whose samples had not received any treatment; Control Group C 1 was only scraped and polished conventionally with Hu-Friedy Gracey curettes 5 and 6; the other samples groups L1, L2, L3, L4 were radiated by diode laser using parameters of power 1,0 W; 1,2 W; 1,4 W; and 1,6 W respectively, 2 times for 10 seconds with 20 seconds intervals between each radiation in continuous mode. The results with relation to the increase of temperature in the interior of the root canal demonstrated that there was an increase of more than 5 degree Celsius. The results of the scanning electron microscope analysis of Control Group C demonstrated great irregularity and ridges on the root surface, with the presence of a dentine layer. Control Group C1 presented a similar aspect to Group L 1's, smoother and more homogeneous surface. Groups L2, L3, and L4 presented scratches alternating with smoother areas showing that fiber contacted the surface of the sample. The results reconfirmed the necessity of further studies using diode laser, with a beam of light emitted in an interrupted mode to improve the control of

  20. Monitoring of temperature profiles and surface morphologies during laser sintering of alumina ceramics

    Directory of Open Access Journals (Sweden)

    Bin Qian

    2014-06-01

    Full Text Available Additive manufacturing of alumina by laser is a delicate process and small changes of processing parameters might cause less controlled and understood consequences. The real-time monitoring of temperature profiles, spectrum profiles and surface morphologies were evaluated in off-axial set-up for controlling the laser sintering of alumina ceramics. The real-time spectrometer and pyrometer were used for rapid monitoring of the thermal stability during the laser sintering process. An active illumination imaging system successfully recorded the high temperature melt pool and surrounding area simultaneously. The captured images also showed how the defects form and progress during the laser sintering process. All of these real-time monitoring methods have shown a great potential for on-line quality control during laser sintering of ceramics.

  1. Measuring evaporation rates of laser-trapped droplets by use of fluorescent morphology-dependent resonances.

    Science.gov (United States)

    Pastel, R; Struthers, A

    2001-05-20

    Morphology-dependent resonances (MDRs) are used to measure accurately the evaporation rates of laser-trapped 1- to 2-mum droplets of ethylene glycol. Droplets containing 3 x 10(-5) M Rhodamine-590 laser dye are optically trapped in a 20-mum hollow fiber by two counterpropagating 150-mW, 800-nm laser beams. A weaker 532-nm laser excites the dye, and fluorescence emission is observed near 560 nm as the droplet evaporates. A complete series of first-order TE and TM MDRs dominates the fluorescent output. MDR mode identification sizes the droplets and provides accurate evaporation rates. We verify the automated MDR mode identification by counting fringes in a videotape of the experiment. The longitudinal spring constant of the trap, measured by analysis of the videotaped motion of droplets perturbed from the trap center, provides independent verification of the laser's intensity within the trap.

  2. Imaging of Norway spruce early somatic embryos with the ESEM, Cryo-SEM and laser scanning microscope.

    Science.gov (United States)

    Neděla, Vilém; Hřib, Jiří; Havel, Ladislav; Hudec, Jiří; Runštuk, Jiří

    2016-05-01

    This article describes the surface structure of Norway spruce early somatic embryos (ESEs) as a typical culture with asynchronous development. The microstructure of extracellular matrix covering ESEs were observed using the environmental scanning electron microscope as a primary tool and using the scanning electron microscope with cryo attachment and laser electron microscope as a complementary tool allowing our results to be proven independently. The fresh samples were observed in conditions of the air environment of the environmental scanning electron microscope (ESEM) with the pressure from 550Pa to 690Pa and the low temperature of the sample from -18°C to -22°C. The samples were studied using two different types of detector to allow studying either the thin surface structure or material composition. The scanning electron microscope with cryo attachment was used for imaging frozen extracellular matrix microstructure with higher resolution. The combination of both electron microscopy methods was suitable for observation of "native" plant samples, allowing correct evaluation of our results, free of error and artifacts.

  3. Structure and Morphology Effects on the Optical Properties of Bimetallic Nanoparticle Films Laser Deposited on a Glass Substrate

    Directory of Open Access Journals (Sweden)

    A. O. Kucherik

    2017-01-01

    Full Text Available Moving nanosecond laser system is used for laser-assisted thermodiffusion deposition of metallic nanoparticles from water-based colloidal solutions. The results obtained for both gold and silver nanoparticles show that film morphology strongly depends on laser scanning speed and the number of passages. We show, furthermore, the possibility of producing bimetallic Au:Ag thin films by laser irradiation of the mixed solutions. As a result of several laser scans, granular nanometric films are found to grow with a well-controlled composition, thickness, and morphology. By changing laser scanning parameters, film morphology can be varied from island structures to quasi-periodic arrays. The optical properties of the deposited structures are found to depend on the film composition, thickness, and mean separation between the particles. The transparency spectra of the deposited films are shown to be defined by their morphology.

  4. Morphologic assessment of dental surface/ glass ionomer cement interface: influence of Er:YAG laser pretreatment

    Directory of Open Access Journals (Sweden)

    Silmara Aparecida Milori Corona

    2012-12-01

    Full Text Available Introduction and objective: The aim of this study was to assess the surface and the substrate/glass ionomer cement (GIC interface after Er:YAG laser irradiation by means of scanning electron microcopy. Material and methods: Thirty human third molars were selected and had their roots removed. Crowns were sectioned to obtain discs that were randomly assigned to three groups according to the surface pretreatment: 40% polyacrylic acid (control; Er:YAG laser irradiation (80mJ/2Hz or Er:YAG laser followed by 40% polyacrylic acid. Two discs of each group were put aside to the surface analysis and the others were bisected. One half received Ketac-Fil and the other received Fuji II LC. Specimens were prepared for SEM and were analyzed under different magnifications. Results: Er:YAG laser group showed no adhesive interface for both enamel and dentin, but strongly damaged the interface build-up for dentin/Fuji II LC. The application of laser irradiation followed by the polyacrylic acid exhibited gaps and irregularities for both substrates. Conclusion: Er:YAG laser irradiation combined or not with 40% polyacrylic acid produced a surface unfavorable for GIC interaction, especially for the resin-modified ones.

  5. Fibre laser cutting stainless steel: Fluid dynamics and cut front morphology

    Science.gov (United States)

    Pocorni, Jetro; Powell, John; Deichsel, Eckard; Frostevarg, Jan; Kaplan, Alexander F. H.

    2017-01-01

    In this paper the morphology of the laser cut front generated by fibre lasers was investigated by observation of the 'frozen' cut front, additionally high speed imaging (HSI) was employed to study the fluid dynamics on the cut front while cutting. During laser cutting the morphology and flow properties of the melt film on the cut front affect cut quality parameters such as cut edge roughness and dross (residual melt attached to the bottom of the cut edge). HSI observation of melt flow down a laser cutting front using standard cutting parameters is experimentally problematic because the cut front is narrow and surrounded by the kerf walls. To compensate for this, artificial parameters are usually chosen to obtain wide cut fronts which are unrepresentative of the actual industrial process. This paper presents a new experimental cutting geometry which permits HSI of the laser cut front using standard, commercial parameters. These results suggest that the cut front produced when cutting medium section (10 mm thick) stainless steel with a fibre laser and a nitrogen assist gas is covered in humps which themselves are covered by a thin layer of liquid. HSI observation and theoretical analysis reveal that under these conditions the humps move down the cut front at an average speed of approximately 0.4 m/s while the covering liquid flows at an average speed of approximately 1.1 m/s, with an average melt depth at the bottom of the cut zone of approximately 0.17 mm.

  6. Relationship between the chemical and morphological characteristics of human dentin after Er:YAG laser irradiation.

    Science.gov (United States)

    Soares, Luís Eduardo Silva; Martin, Ovídio César Lavesa; Moriyama, Lilian Tan; Kurachi, Cristina; Martin, Airton Abrahão

    2013-06-01

    The effects of laser etching on dentin are studied by microenergy-dispersive x-ray fluorescence spectrometry (μ-EDXRF) and scanning electron microscopy (SEM) to establish the correlation of data obtained. Fifteen human third molars are prepared, baseline μ-EDXRF mappings are performed, and ten specimens are selected. Each specimen received four treatments: acid etching (control-CG) or erbium:yttrium-aluminum-garnet (Er:YAG) laser irradiation (I-100 mJ, II-160 mJ, and III-220 mJ), and maps are done again. The Ca and P content are significantly reduced after acid etching (pmappings illustrated that acid etching created homogeneous distribution of inorganic content over dentin. Er:YAG laser etching (220 mJ) produced irregular elemental distribution and changed the stoichiometric proportions of hydroxyapatite, as showed by an increase of mineral content. Decreases and increases of mineral content in the μ-EDXRF images are correlated to holes and mounds, respectively, as found in SEM images.

  7. Investigations of morphological features of picosecond dual-wavelength laser ablation of stainless steel

    Science.gov (United States)

    Zhao, Wanqin; Wang, Wenjun; Mei, Xuesong; Jiang, Gedong; Liu, Bin

    2014-06-01

    Investigations on the morphological features of holes and grooves ablated on the surface of stainless steel using the picosecond dual-wavelength laser system with different powers combinations are presented based on the scarce researches on morphology of dual-wavelength laser ablation. The experimental results show the profiles of holes ablated by the visible beam appear V-shaped while those for the near-infrared have large openings and display U-shaped, which are independent of the ablation mechanism of ultrafast laser. For the dual-wavelength beam (a combination of visible beam and near-infrared), the holes resemble sunflower-like structures and have smoother ring patterns on the bottom. In general, the holes ablated by the dual-wavelength beam appear to have much flatter bottoms, linearly sloped side-walls and spinodal structures between the bottoms of the holes and the side-walls. Furthermore, through judiciously combining the powers of the dual-wavelength beam, high-quality grooves could be obtained with a flat worm-like structure at the bottom surface and less resolidified melt ejection edges. This study provides insight into optimizing ultrafast laser micromachining in order to obtain desired morphology.

  8. Surface morphological modification of crosslinked hydrophilic co-polymers by nanosecond pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Primo, Gastón A.; Alvarez Igarzabal, Cecilia I. [IMBIV (CONICET), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba X5000HUA (Argentina); Pino, Gustavo A.; Ferrero, Juan C. [INFIQC (CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, and Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Córdoba X5000IUS (Argentina); Rossa, Maximiliano, E-mail: mrossa@fcq.unc.edu.ar [INFIQC (CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, and Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Córdoba X5000IUS (Argentina)

    2016-04-30

    Graphical abstract: - Highlights: • Laser-induced surface modification of crosslinked hydrophilic co-polymers by ns pulses. • Formation of ablation craters observed under most of the single-pulse experimental conditions. • UV laser foaming of dried hydrogel samples resulting from single- and multiple-pulse experiments. • Threshold values of the incident laser fluence reported for the observed surface modifications. • Lower threshold fluences for acrylate-based, compared to acrylamide-based hydrogels. - Abstract: This work reports an investigation of the surface modifications induced by irradiation with nanosecond laser pulses of ultraviolet and visible wavelengths on crosslinked hydrophilic co-polymeric materials, which have been functionalized with 1-vinylimidazole as a co-monomer. A comparison is made between hydrogels differing in the base co-monomer (N,N-dimethylaminoethyl methacrylate and N-[3-(dimethylamino)propyl] methacrylamide) and in hydration state (both swollen and dried states). Formation of craters is the dominant morphological change observed by ablation in the visible at 532 nm, whereas additional, less aggressive surface modifications, chiefly microfoams and roughness, are developed in the ultraviolet at 266 nm. At both irradiation wavelengths, threshold values of the incident laser fluence for the observation of the various surface modifications are determined under single-pulse laser irradiation conditions. It is shown that multiple-pulse irradiation at 266 nm with a limited number of laser shots can be used alternatively for generating a regular microfoam layer at the surface of dried hydrogels based on N,N-dimethylaminoethyl methacrylate. The observations are rationalized on the basis of currently accepted mechanisms for laser-induced polymer surface modification, with a significant contribution of the laser foaming mechanism. Prospective applications of the laser-foamed hydrogel matrices in biomolecule immobilization are suggested.

  9. Surface morphological modification of crosslinked hydrophilic co-polymers by nanosecond pulsed laser irradiation

    Science.gov (United States)

    Primo, Gastón A.; Alvarez Igarzabal, Cecilia I.; Pino, Gustavo A.; Ferrero, Juan C.; Rossa, Maximiliano

    2016-04-01

    This work reports an investigation of the surface modifications induced by irradiation with nanosecond laser pulses of ultraviolet and visible wavelengths on crosslinked hydrophilic co-polymeric materials, which have been functionalized with 1-vinylimidazole as a co-monomer. A comparison is made between hydrogels differing in the base co-monomer (N,N-dimethylaminoethyl methacrylate and N-[3-(dimethylamino)propyl] methacrylamide) and in hydration state (both swollen and dried states). Formation of craters is the dominant morphological change observed by ablation in the visible at 532 nm, whereas additional, less aggressive surface modifications, chiefly microfoams and roughness, are developed in the ultraviolet at 266 nm. At both irradiation wavelengths, threshold values of the incident laser fluence for the observation of the various surface modifications are determined under single-pulse laser irradiation conditions. It is shown that multiple-pulse irradiation at 266 nm with a limited number of laser shots can be used alternatively for generating a regular microfoam layer at the surface of dried hydrogels based on N,N-dimethylaminoethyl methacrylate. The observations are rationalized on the basis of currently accepted mechanisms for laser-induced polymer surface modification, with a significant contribution of the laser foaming mechanism. Prospective applications of the laser-foamed hydrogel matrices in biomolecule immobilization are suggested.

  10. Ablation morphology of germanium with multi-pulse femtosecond laser%多脉冲飞秒激光对锗材料的烧蚀效应

    Institute of Scientific and Technical Information of China (English)

    辛建婷; 谭放; 罗国强; 马小军; 赵宗清; 韩丹

    2011-01-01

    开展了脉宽为40 fs的不同数量激光脉冲对锗材料的烧蚀效应实验,采用扫描电镜、激光共聚焦显微镜等方法对不同数量的飞秒激光脉冲作用下锗材料表面烧蚀区进行了检测,并对作用后材料烧蚀形貌演化规律进行了分析,初步分析了锗材料烧蚀区周围形成的不同环区的形貌特征及成因,对各环区烧蚀形貌特征随激光作用脉冲数的增加而产生的形貌演化过程进行了观测.并给出单脉冲飞秒激光对锗材料的烧蚀阈值为1.2 J·cm-2,采用激光共聚焦显微镜测得该阈值条件下单个飞秒激光脉冲对锗材料的烧蚀深度约为150 nm.%Ablation morphology on germanium surface using multi-pulse femtosecond laser is reported. The SEM and laser focus give magnified views of the ablated portion. The ablation morphology shows a periodic surface structure with various laser pulses. And the formation of amorphous rings and ripples in the damage spot is discussed. The ablation threshold is 1. 2 J ? cm-2 and the ablation depth with single femtosecond laser pulse is about 150 nm. It is meanful for research the interaction of femtosec-ond laser and material, and the application of femtosecond laser in micromachining.

  11. Effect of the repaired damage morphology of fused silica on the modulation of incident laser

    Science.gov (United States)

    Gao, X.; Jiang, Y.; Qiu, R.; Zhou, Q.; Zuo, R.; Zhou, G. R.; Yao, K.

    2017-02-01

    Local CO2 laser treatment has proved to be the most promising method to extend the life-time of fused silica. However, previous experimental data show that some raised rims are observed around the mitigated sites left from the mitigation process, which will result in hazardous light modulation to the downstream optics. In this work, the morphology features of mitigated sites on the surface of fused silica optics were analyzed in detail. According to measured morphology features, a 3D analytical model for simulating the modulation value induced by mitigated site has been developed based on the scalar diffraction theory. The diffraction patterns at a discrete distance downstream from each mitigated site are measured. The influences of geometry, laser wavelength and refractive index of substrates on the modulation by repaired damage morphology at different distances are discussed, respectively. The analytical model is usable and representative to evaluate the hazardous modulation induced by repaired damage morphology to downstream optics. Results on this research suggest that the downstream intensification can be suppressed by controlling the morphology features of mitigated sites, which provides a direction for the development and improvement of the mitigated techniques of damage optics.

  12. Structure and morphology of laser-ablated WO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, O.M.; Swapnasmitha, A.S. [Sri Venkateswara University, Department of Physics, Tirupati (India); John, J.; Pinto, R. [Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai (India)

    2005-11-01

    The structure and surface morphology of WO{sub 3} thin films deposited by a laser-ablation technique have been found to be strongly dependent on the deposition conditions and the nature of the substrate. By precisely controlling the substrate temperature and the oxygen partial pressure, amorphous, polycrystalline, nano-crystalline and iso-epitaxial WO{sub 3} thin films were successfully grown. The structure and surface morphological features of the films from X-ray diffraction and atomic force microscopy data are described in relation to the deposition conditions. (orig.)

  13. In situ 24 kHz coherent imaging of morphology change in laser percussion drilling.

    Science.gov (United States)

    Webster, Paul J L; Yu, Joe X Z; Leung, Ben Y C; Anderson, Mitchell D; Yang, Victor X D; Fraser, James M

    2010-03-01

    We observe sample morphology changes in real time (24 kHz) during and between percussion drilling pulses by integrating a low-coherence microscope into a laser micromachining platform. Nonuniform cut speed and sidewall evolution in stainless steel are observed to strongly depend on assist gas. Interpulse morphology relaxation such as hole refill is directly imaged, showing dramatic differences in the material removal process dependent on pulse duration/peak power (micros/0.1 kW, ps/20 MW) and material (steel, lead zirconate titanate PZT). Blind hole depth precision is improved by over 1 order of magnitude using in situ feedback from the imaging system.

  14. IR and UV laser-induced morphological changes in silicon surface under oxygen atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Jarquin, J.; Fernandez-Guasti, M.; Haro-Poniatowski, E.; Hernandez-Pozos, J.L. [Laboratorio de Optica Cuantica, Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco No. 186, Col. Vicentina, C.P. 09340, Mexico D.F. (Mexico)

    2005-08-01

    We irradiated silicon (100) wafers with IR (1064 nm) and UV (355 nm) nanosecond laser pulses with energy densities within the ablation regime and used scanning electron microscopy to analyze the morphological changes induced on the Si surface. The changes in the wafer morphology depend both on the incident radiation wavelength and the environmental atmosphere. We have patterned Si surfaces with a single focused laser spot and, in doing the experiments with IR or UV this reveals significant differences in the initial surface cracking and pattern formation, however if the experiment is carried out in O{sub 2} the final result is an array of microcones. We also employed a random scanning technique to irradiate the silicon wafer over large areas, in this case the microstructure patterns consist of a ''semi-ordered'' array of micron-sized cones. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. In vitro effects of Nd:YAG laser radiation on blood: a quantitative and morphologic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Borrero, E.; Rosenthal, D.; Otis, J.B.

    1988-01-01

    Use of the Neodymium: yttrium -aluminum -garnet (Nd:YAG) laser to recanalize stenosed arteries may require delivery of the beam through blood. To assess the degree of hemolysis and debris formation, 54 samples of citrated whole blood were exposed to Nd:YAG laser radiation of varying powers (10, 20 and 30 watts) and duration (1, 2.5 and 5 seconds). Compared to control samples which were not subjected to laser light, there was no significant decrease in hematocrit (41 to 40.5 +/- 5%), hemoglobin concentration (13.8 to 13.8 +/- .06 g/1OO ml), or increase in free hemoglobin concentration. Debris weight (from .45 +/- .002 to .45 +/- .002 mg), as well as the white blood cell count, was also not significantly changed (from 5,400 to 5,200 +/- 240 WBC/cm). Light microscopy examination of debris from samples of whole blood, washed erythrocytes, and platelet-rich plasma subjected to the laser at 30 watts for five seconds failed to demonstrate the presence of membrane denaturation of blood elements, as compared with the morphologic changes observed in whole blood samples exposed to a hot tip rather than Nd:YAG laser radiation. Nd:YAG laser can be used intravascularly without fear of hemolysis or debris micro-embolization up to a power of 30 watts for five seconds.

  16. Investigation on corrosion stratigraphy and morphology in some Iron Age bronze alloys vessels by OM, XRD and SEM-EDS methods

    Science.gov (United States)

    Oudbashi, Omid; Hasanpour, Ata; Davami, Parviz

    2016-04-01

    The recently study of the corrosion in some bronze artefacts from the Sangtarashan Iron Age site, western Iran, was established to identify corrosion morphology and mechanism in these objects. The corrosion layers in 22 samples were studied by optical microscopy, scanning electron microscopy-energy-dispersive X-ray spectroscopy and X-ray diffraction methods. The results showed that a thin corrosion crust has formed on the surface of bronzes with a triple-layer structure, including two internal and one external corrosion layers. The formation of these layers is due to copper leaching from the bronze surface. The internal corrosion part has been a compact, tin-rich corrosion/oxidation product (noble patina) with some evidences from original metallurgical aspects of the bronze as well as a very thin layer beneath the tin-rich layer. External corrosion products have been identified as basic copper carbonates, malachite and azurite. Based on the results, the corrosion morphology in the Sangtarashan Iron Age bronzes is due to long-term burial in an appropriate environment in a moderately corrosive soil. Although it is the first time to investigate Iron Age bronzes from Iran, this corrosion morphology is partially similar to type I corrosion morphology observed in archaeological bronze objects; nevertheless, some deviations are visible in comparison with previously established patterns.

  17. Composition, XRD and morphology study of laser prepared LiNbO{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Jelinek, M.; Remsa, J.; Kocourek, T. [Institute of Physics ASCR v.v.i., Prague 8 (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Sitna, Kladno (Czech Republic); Havranek, V. [Nuclear Physics Institute ASCR, Rez near Prague (Czech Republic); Vincze, A.; Bruncko, J. [International Laser Centre, Bratislava 4 (Slovakia); Studnicka, V. [Institute of Physics ASCR v.v.i., Prague 8 (Czech Republic); Rubesova, K. [Institute of Chemical Technology, Prague 6 (Czech Republic)

    2013-03-15

    LiNbO{sub 3} films were deposited by PLD from LiNbO{sub 3} crystalline or from three different stoichiometric or Li-enriched LiNbO{sub 3} targets. Polycrystalline films were prepared on SiO{sub 2}/Si or sapphire substrates at temperatures T{sub S} {proportional_to}650-750 C. Main attention was paid to the influence of targets preparation and the deposition conditions on films composition, morphology and crystallinity. The thin-film morphology was determined by SEM microscopy. The composition was measured by SIMS, RBS, PIXE and PIGE methods. Highly oriented, smooth and stoichiometric LiNbO{sub 3} films were synthesized. (orig.)

  18. Damage morphology and mechanism in ablation cutting of thin glass sheets with picosecond pulsed lasers

    Science.gov (United States)

    Sun, Mingying; Eppelt, Urs; Hartmann, Claudia; Schulz, Wolfgang; Zhu, Jianqiang; Lin, Zunqi

    2016-06-01

    We experimentally investigated the morphology and mechanism of laser-induced damage in the ablation cutting of thin glass sheets with picosecond pulsed lasers and we compared the experimental results to our models. After several passes of laser ablation, we observed two different kinds of damage morphologies on the cross-section of the cut channel. They are distinguished to be the damage region caused by high-density free-electrons and the heat-affected zone due to the heat accumulation, respectively. Furthermore, micro-cracks can be observed on the top surface of the workpiece near the cut edge. The nano-cracks could be generated by high energy free-electrons but opened and developed to be visible micro-cracks by thermal stress generated in the heat-affected zone. The crack length was proportional to the volume of heat-affected zone. Heat-affected-zone and visible-cracks free conditions of glass cutting were achieved by controlling the repetition rate and spatial overlap of laser pulses.

  19. Sem-EDXRF and ICP-MS investigation of the morphological and chemical composition of depleted uranium particles from Kuwait areas affected by the 1991 Gulf War

    Energy Technology Data Exchange (ETDEWEB)

    Danesi, P.R.; Burns, K.; Campbell, M.; Ciurapinski, A.; Donohue, D.; Admon, U.; Burkart, W. [International Atomic Energy Agency Vienna (Austria)

    2004-07-01

    Selected soil samples collected in Kuwait locations where residues of DU ammunition existed as a legacy of the 1991 Gulf War, have been investigated by scanning electron microscopy equipped with an energy dispersive X-ray fluorescence detector (SEM- EDXRF) with the objective to identify the presence of DU particles and characterize their shape and size. The isotopic and total bulk concentrations of uranium in the samples were measured by inductively coupled plasma mass spectrometry (ICP-MS) and alpha spectrometry. The samples studied by SEM-EDXRF were prepared by gently tapping an aluminum stab covered with a doubled-sided adhesive carbon disk, thereby ensuring that the physical integrity of the samples was maintained. The results have indicted that soil collected just below ({approx} 5 cm) corroded DU penetrators contained several DU oxide particles (isotopic ratio {sup 235}U/{sup 238}U = 0.0021) ranging in size from 1 to 10 microns (approximate geometrical diameter) having an irregular shape. The particles are most likely corrosion products from the DU penetrators. Some particles are imbedded in a larger matrix containing aluminum oxide (corrosion product of the penetrator jacket) and silica (sand). Swipes collected inside holes in tanks hit by DU ammunition, using ultra-pure cotton cloths, have indicated the presence of many small DU particles in the range 1 to 10 microns. In this case the particles were found to contain also small quantities of Fe, probably the results on alloying process occurring when the DU penetrators impact with the tank armor. (author)

  20. Material morphological characteristics in laser ablation of alpha case from titanium alloy

    Science.gov (United States)

    Yue, Liyang; Wang, Zengbo; Li, Lin

    2012-08-01

    Alpha case (an oxygen enriched alloy layer) is commonly formed in forged titanium alloys during the manufacturing process and it reduces the service life of the materials. This layer is normally removed mechanically or chemically. This paper reports the feasibility and characteristics of using a short pulsed laser to remove oxygen-enriched alpha case layer from a titanium alloy (Ti6Al4V) substrate. The material removal rate, i.e., ablation rate, and ablation threshold of the alpha case titanium were experimentally determined, and compared with those for the removal of bulk Ti6Al4V. Surface morphologies of laser processed alpha case titanium layer, especially that of cracks at different ablated depths, were carefully examined, and also compared with those for Ti6Al4V. It has been shown that in the alpha case layer, laser ablation has always resulted in crack formation while for laser ablation of alpha case free Ti6Al4V layers, cracking was not present. In addition, the surface is rougher within the alpha case layer and becomes smoother (Ra - 110 nm) once the substrate Ti-alloy is reached. The work has demonstrated that laser is a feasible processing tool for removing alpha case titanium, and could also be used for the rapid detection of the presence of alpha case titanium on Ti6Al4V surfaces in aerospace applications.

  1. In vitro effects of argon laser radiation on blood: quantitative and morphologic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Abela, G.S.; Crea, F.; Smith, W.; Pepine, C.J.; Conti, C.R.

    1985-02-01

    Use of the argon laser to recanalize stenosed arteries may require delivery of the beam through blood. To assess the degree of hemolysis and debris formation, 84 samples of citrated whole blood were exposed to argon laser radiation with varying power (1, 2 and 3 watts) and duration (5, 10, 20 and 40 seconds). Compared with control samples, only blood samples exposed to a power of 3 watts for 40 seconds showed a marked decrease in hematocrit (from 37 +/- 1.3 to 33 +/- 1.4%, p less than 0.01) and a marked increase in both free hemoglobin concentration (from 0.2 +/- 0.2 to 1.3 +/- 0.5 g/100 ml, p less than 0.01) and debris weight (from 0.9 +/- 0.3 to 2.8 +/- 0.5 mg, p less than 0.01). Scanning electron microscopy of debris from samples of whole blood, washed erythrocytes and platelet-rich plasma lased at 3 watts for 40 seconds documented the presence of membrane denaturation of blood elements, resulting in their fusion to form complex mesh-like conglomerates. Similar morphologic changes were observed in whole blood samples exposed to a ''hot tip'' rather than laser radiation. These data indicate that: 1) argon laser radiation with a power of 3 watts does not produce apparent hemolysis or debris formation for exposure periods up to 20 seconds, and 2) the effects of laser radiation on blood are probably mediated by thermal denaturation of cell membranes, as suggested by the same morphologic changes produced by thermal injury from a ''hot tip.''

  2. Part II: morphological analysis of embryonic development following femtosecond laser manipulation

    Science.gov (United States)

    Kohli, V.; Elezzabi, A. Y.

    2008-02-01

    The zebrafish (Danio rerio) is an attractive model system that has received wide attention for its usefulness in the study of development and disease. This organism represents a closer analog to humans than the common invetebrates Drosophila melanogaster and Caenorhabditis elegans, making this species an ideal model for human health research. Non-invasive manipulation of the zebrafish has been challenging, owing to the outer proteinaceous membrane and multiple embryonic barriers. A novel tool capable of manipulating early cleavage stage embryonic cells would be important for future advancements in medial research and the aquaculture industry. Herein, we demonstrate the laser surgery of early cleavage stage (2-cell) blastomere cells using a range of average laser powers and beam dwell times. Since the novelty of this manipulation tool depends on its non-invasive application, we examined short- and long-term laser-induced developmental defects following embryonic surgery. Laser-manipulated embryos were reared to 2 and 7 days post-fertilization and compared to control embryos at the same developmental stages. Morphological analysis was performed using light microscopy and scanning electron microscopy. Developmental features that were examined included the antero- and dorsal-lateral whole body views of the larvae, the olfactory pit, dorsal, ventral and pectoral fins, notochord, pectoral fin buds, otic capsule, otic vesicle, neuromast patterning, and kinocilia of the olfactory pit rim and cristae of the lateral wall of the ear. Laser-manipulated embryos developed normally relative to the controls, with developmental patterning and morphology at 2 and 7 days indistinguishable from control larvae.

  3. Morphological and chemical analysis of bainite in Cu-17Al-11Mn (at.%) alloys by using orthogonal FIB-SEM and double-EDS STEM.

    Science.gov (United States)

    Motomura, Shunichi; Hara, Toru; Omori, Toshihiro; Kainuma, Ryosuke; Nishida, Minoru

    2016-06-01

    In this study, new microscopy techniques were developed for understanding the mechanism for the bainitic transformation in a Cu-17Al-11Mn (at%) alloy. An orthogonally arranged focused ion beam and a scanning electron microscope were employed to observe three-dimensional (3D) morphology of the bainite phase, in addition to compositional analysis by using a scanning transmission electron microscope equipped with a double-detector energy-dispersive X-ray spectrometer system. The 3D morphology of these samples was observed at different aging times and aging temperatures; the results obtained indicated that with increasing aging time and/or aging temperature, the bainite phase at the initial stage of formation exhibits a plate-like shape, which changes to a lenticular form. A habit plane was uniquely determined as ∼{9 3 2} by the combination of 3D image reconstruction and an electron back-scattered diffraction technique. The compositional analysis revealed the spatial distribution of the compositional variation between the bainite and matrix phases in the initial stages of the transformation. In the bainite phase, the Cu concentration was higher, while the concentrations of Al and Mn were lower than those in the surrounding matrix, indicative of the diffusion of the constituent elements with the growth of the bainite phase. © The Author 2016. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Surface morphology of highly ordered nanotube formed and laser textured beta titanium alloys.

    Science.gov (United States)

    Kim, Jae-Un; Jeong, Yong-Hoon; Choe, Han-Cheol

    2013-03-01

    The aim of the present study is to produce and characterize a well-controlled surface texture on Ti-35Nb-xHf alloys to promote osseointegration. Ti-35Nb-xHf (x = 0, 3, 7 and 15 wt.%) alloys were prepared by arc melting and heat treated for 12 hr at 1000 degrees C in an argon atmosphere and then water quenching. For surface texturing, an amplified Ti: sapphire laser system was used for generating 184 femtosecond (FS, 10(-15) sec) laser pulses with the pulse energy over 30 mJ at a 1 kHz repetition rate with a central wavelength of 800 nm. The nanotube formation was achieved by anodizing a Ti-35Nb-xHf alloy in H3PO4 electrolytes containing 0.8 wt.% NaF at room temperature. The surface morphology of nano/micro structure will enhance osseointegration and cell adhesion.

  5. Optical, structural and morphological properties of zirconia nanoparticles prepared by laser ablation in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Borodina, T I; Val' yano, G E; Gololobova, O A; Karpukhin, V T; Malikov, M M; Strikanov, D A [Joint Institute for High Temperatutes, Russian Academy of Sciences (Russian Federation)

    2014-09-30

    Absorption, fluorescence and Raman spectra, the structural composition and morphology of zirconia nanoparticles synthesised via the laser ablation of a metal in water and aqueous solutions of the sodium dodecyl sulphate (SDS) surfactant have been studied using absorption spectroscopy, Raman spectroscopy, X-ray diffraction and scanning electron microscopy. The results demonstrate that, exposing zirconium to intense nanosecond laser pulses at a high repetition rate in these liquids, one can obtain stable cubic, tetragonal and monoclinic crystalline phases of nanozirconia with a particle size in the range 40 – 100 nm and a Zr – SDS organic – inorganic composite. The absorption and fluorescence of the synthesised zirconia strongly depend on the SDS concentration in the starting solution. The gas – vapour bubbles forming during ablation are shown to serve as templates for the formation of hollow nanoand microstructures. (nanostructures)

  6. Morphological and animal study of titanium dental implant surface induced by blasting and high intensity pulsed Nd-glass laser

    Energy Technology Data Exchange (ETDEWEB)

    Karacs, A.; Joob Fancsaly, A.; Divinyi, T.; Peto, G.; Kovach, G

    2003-03-03

    Machined dental implants of titanium were blasted with Al{sub 2}O{sub 3} powder of 250 {mu}m particle size. The surface was irradiated in vacuum with a Nd-glass pulsed laser at 1-3 J pulse energies. The morphology of these surfaces was investigated by optical and scanning electron microscopy. The low intensity laser treatment resulted in some new irregularities but we can observe the blasted elements and caves from the original blasted surface too. The blasted elements were washed out and a new surface morphology was induced by the high intensity laser treatment. The osseointegration was determined by measuring the removal torque in the rabbit experiments. The results were referred to the as machined surface. The blasting slightly increased the removal torque. The laser irradiation increased the removal torque significantly, more by a factor of 1.5 compared to the reference at high laser intensity. This shows the influence of the surface morphology on the osseointegration. The combination of the blasting with the laser irradiation is considered a method to determine the morphology optimal for the osseointegration because the pulsed laser irradiation caused modifications of the micrometer sized surface elements and decreases possible surface contamination.

  7. Monitoring of the morphologic reconstruction of deposited ablation products in laser irradiation of silicon

    Directory of Open Access Journals (Sweden)

    Vlasova M.

    2008-01-01

    Full Text Available Using electron microscopy, atomic force microscopy, X-ray microanalysis, and IR spectroscopy, it was established that, in the regime of continuous laser irradiation of silicon at P = 170 W in different gaseous atmospheres with an oxygen impurity, SiOx composite films with a complex morphology form. The main components of ablation products are clusters that form during flight of ablation products and as a result of separation of SiOx-clusters from the zone of the irradiation channel. The roughness and density of the films depend on the heating temperature of the target surface and the type of deposited clusters.

  8. The influence of a novel in-office tooth whitening procedure using an Er,Cr:YSGG laser on enamel surface morphology.

    Science.gov (United States)

    Dionysopoulos, Dimitrios; Strakas, Dimitrios; Koliniotou-Koumpia, Eugenia

    2015-08-01

    The purpose of this in vitro study was to evaluate the influence of a novel in-office tooth whitening procedure using Er,Cr:YSGG laser radiation on bovine enamel. Forty-eight enamel specimens were prepared from bovine canines and divided into four groups: Group 1 specimens (control) received no whitening treatment; Group 2 received whitening treatment with an at-home whitening agent (22% carbamide peroxide) for 7 days; Group 3 received whitening treatment with a novel in-office whitening agent (35% H(2)O(2)); Group 4 received the same in-office whitening therapy with Group 3 using Er,Cr:YSGG laser in order to accelerate the whitening procedure. The specimens were stored for 10 days after the whitening treatment in artificial saliva. Vickers hardness was determined using a microhardness tester and surface roughness was evaluated using a VSI microscope. Three specimens of each experimental group were examined under SEM and the mineral composition of the specimens was evaluated using EDS. Data were statistically analyzed using one-way ANOVA, Tukey's post-hoc test, Wilcoxon signed rank and Kruskal-Wallis tests (a = 0.05). The surface microhardness of the enamel was reduced after the in-office whitening treatments (Ptreatment (P> 0.05). Moreover, the surface roughness was not significantly changed after tooth whitening. EDS analysis did not show alterations in the enamel mineral composition, while SEM observations indicated changes in the surface morphology, especially after in-office tooth whitening (Plaser-assisted whitening treatment with Er,Cr:YSGG laser did not affect the alterations in enamel surface compared with the conventional in-office whitening technique. © 2015 Wiley Periodicals, Inc.

  9. Structural, morphological and optical characterizations of ZnO:Al thin films grown on silicon substrates by pulsed laser deposition

    Science.gov (United States)

    Alyamani, A.; Sayari, A.; Albadri, A.; Albrithen, H.; El Mir, L.

    2016-09-01

    The pulsed laser deposition (PLD) technique is used to grow Al-doped ZnO (AZO) thin films at 500 ° C on silicon substrates under vacuum or oxygen gas background from ablating AZO nanoparticle targets synthesized via the sol-gel process. The structural, morphological and optical properties were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and spectroscopic ellipsometry (SE) techniques. XRD and TEM images show that AZO powder has a wurtzite-type structure and is composed of small prismatic-like shape nanoparticles with an average size of 30nm. The structural properties of the AZO films grown under oxygen show no significant changes compared to those of the film grown under vacuum. However, the optical properties show a dependence on the growth conditions of the AZO films. Highly c -axis-oriented AZO thin films were obtained with grain size ˜ 15 nm. The stress in the AZO films is tensile as measured from the c -parameter. The dielectric function, the refractive index and the extinction coefficient as a function of the photon energy for the AZO films were determined by using spectroscopic ellipsometry measurements in the photon energy region from 1 to 6eV. The band gap energy was observed to slightly decrease in the presence of the O2 gas background and this may be attributed to the stress. The surface and volume energy loss functions are calculated and exhibit different behaviors in the energy range 1-6eV. Refractive indices of 1.9-2.1 in the visible region were obtained for the AZO films. Also, the electronic carrier concentration appears to be related to the presence of O2 during the growth process.

  10. Ao leitor sem medo

    Directory of Open Access Journals (Sweden)

    José Eisenberg

    2000-05-01

    Full Text Available O texto resenha Ao leitor sem medo, de Renato Janine Ribeiro (Belo Horizonte, UFMG, 1999.This text is a review of Ao leitor sem medo by Renato Janine Ribeiro (Belo Horizonte, UFMG, 1999

  11. Emittance dependence on anode morphology of an ion beam provided by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Velardi, L.; Delle Side, D.; Nassisi, V., E-mail: vincenzo.nassisi@le.infn.it

    2014-07-15

    Highlights: •We studied the characteristics of ion beams generated by laser ablation. •We varied the geometric configuration of the extracting electrode. •The emittance evaluation was performed by the pepper pot method utilizing radio-chromic films. -- Abstract: In this work, we studied the characteristics of ion beams generated by Platone accelerator in different anode configurations. The accelerator is a laser ion source with two gaps which accelerate the ions in cascade. The laser is a ns pulsed KrF able to apply irradiances of 10{sup 9}–10{sup 10} W/cm{sup 2}. The target ablated was pure disk of Cu. The accelerating voltage applied in this work was 60 kV. The emittance evaluation was performed by the pepper pot method utilizing radio-chromic films, EBT Gafchromic, as sensible targets. The study was performed by varying the geometric configuration of the anode (the extracting electrode), modifying the hole morphology, e.g. a plane and curved grid were mounted in order to change the extraction configuration. The results were compared with the ones obtained with the extraction hole without any grid. For the normalized emittance the lowest value was 0.20π mm mrad.

  12. Pulsed-laser printing of silver nanoparticles ink: control of morphological properties.

    Science.gov (United States)

    Rapp, Ludovic; Ailuno, Julie; Alloncle, Anne Patricia; Delaporte, Philippe

    2011-10-24

    Fine electrically-conductive patterns of silver nanoparticles ink have been laser printed using the laser-induced forward transfer (LIFT) technique. LIFT is a technique that offers the possibility of printing patterns with high spatial resolution from a wide range of materials in solid or liquid state. Influence of drying the ink film, previous to its transfer, on the printed droplet morphology is discussed. The laser pulse energy and donor-receiver substrate separation were systematically varied and their effects on the transferred droplets were analyzed. The use of an intermediate titanium dynamic release layer was also investigated and demonstrated the possibility of a better control of both the size and shape of the printed patterns. Conditions have been determined for printing flat-top droplets with sharp edges. 21 µm width silver lines with 80 nm thickness have been printed with a smooth convex profile. Electrical resistivities of the transferred patterns are only 5 times higher than the bulk silver. © 2011 Optical Society of America

  13. Clinical and morphologic evaluation of Er:YAG laser action at the front of cervical dentinal hypersensitivity; Avaliacao clinica e morfologica da acao do laser de Er:YAG frente a hipersensibilidade dentinaria cervical

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Dalva Maria

    2001-07-01

    This work was achieved in vivo and in vitro to evaluate the efficiency of Er:YAG laser in the cervical dentinal hypersensitivity treatment (HSDC). The Clinical study was achieved in patients with HSDC. The treatment was realized in five sessions: the first for selection, the second for exams (clinic and X-Ray) and trying to remove the etiologic factors that could cause the HSDC. The third and fourth sessions were subjected to the radiation with that protocol: 60 mJ energy ,2 Hz frequency, 6 mm out of focus, under air cooling, 20 seconds each application which the same was repeated four times with one minute breaks, which scanning movements and without using anaesthetics. The fifth was evaluation. The patients were evaluated and registered in a subject scale of pain 0 to 3, in the beginning and end of each session of irradiation, and one month after the last session. The results showed that for the irradiated group occurs significant differences in the beginning of each session and between. For the control group did not occur significant differences in the beginning and after each session, but did show a difference between the sessions. As the control group as the irradiated group, had reduction of sensibility between the session. For the morphologic study nine teeth were selected, 7 molars and 2 pre-molars from operative dentistry discipline. Half of the surface was irradiated with Er:YAG laser, the same protocol used in vivo, and the other half was used as a control without receiving any laser irradiation. Subsequently, specimens were prepared for SEM examinations. The results showed that laser treated surfaces showed a reduction of dentine tubular diameter with partial or total closure of the dentine tubules. For the control group, it was observed bigger amounts smear layer and open dentine tubular. The results obtained indicated that the Er:YAG laser can contribute to the HSDC treatment. (author)

  14. Influence of multi-wavelength laser irradiation of enamel and dentin surfaces on surface morphology and permeability

    Science.gov (United States)

    Chang, Nai-Yuan N.; Jew, Jamison; Simon, Jacob C.; Chan, Kenneth H.; Lee, Robert C.; Fried, William A.; Cho, Jinny; Darling, Cynthia L.; Fried, Daniel

    2017-02-01

    UV and IR lasers can be used to specifically target protein, water, and the mineral phase of dental hard tissues to produce varying changes in surface morphology. In this study, we irradiated enamel and dentin surfaces with various combinations of lasers operating at 0.355, 2.94, and 9.4 μm, exposed those surfaces to topical fluoride, and subsequently evaluated the influence of these changes on surface morphology and permeability. Digital microscopy and surface dehydration rate measurements were used to monitor changes in the samples overtime. The surface morphology and permeability (dehydration rate) varied markedly with the different laser treatments on enamel. On dentin, fluoride was most effective in reducing the permeability.

  15. Laser-initiated magnetization reversal and correlated morphological effects visualized with in situ Fresnel transmission electron microscopy

    Science.gov (United States)

    Schliep, Karl B.; Chen, Jun-Yang; Li, Mo; Wang, Jian-Ping; Flannigan, David J.

    2016-09-01

    Laser-initiated switching of magnetization direction in ferrimagnetic rare-earth-transition-metal (RE-TM) alloys—whether laser induced or photothermal via compensation point—is being vigorously pursued owing to the promise of extending operating frequencies of magnetic devices into the terahertz regime. Despite intense interest, however, the effects of repeated laser exposure on the film structure and subsequent switching behavior have yet to be investigated. In order to better understand the correlated effects of femtosecond-laser irradiation on both the magnetic response and photoinduced morphological variations of RE-TM alloys, we performed in situ Fresnel transmission electron microscopy (TEM) on T b23C o77 thin films with Ta protecting layers. Via optical access to the specimen in a modified TEM, we irradiated the thin films in situ with both individual and series of femtosecond optical pulses, and correlated laser-induced changes in magnetic domain-wall formation and growth with photothermal crystal formation and accompanying pinned magnetic sites. We find that, for a range of applied laser fluences and numbers of individual pulses, several distinct regions are formed displaying varied magnetic behavior (switchable, nonswitchable, demagnetized) and morphological features (small-to-large crystal-grain variations). Through a series of systematic studies, we quantified these linked magnetic and morphological properties as a function of laser fluence, number of pulse-train cycles, and number of individual femtosecond-laser pulses and the duration between each. Our results show how the sensitive connection between magnetic behavior and morphological structure can emerge in magneto-optic experiments across several parameters, thus illustrating the need for rigorous characterization so that potential operating regimes may be universally identified.

  16. Kinetic and morphological differentiation of ettringites in plain and blended Portland cements with metakaolin and the ASTM C 452-68 test. Part II: Morphological differentiation by SEM and XRD analysis

    Directory of Open Access Journals (Sweden)

    Talero, R.

    2009-03-01

    Full Text Available The same cementitious materials (OPCs, SRPCs and matekaolin, MK, the same blended cements and the same ASTM C 452-68 test than in Part I, were used. Other complementary determinations were: chemical analysis of cementing materials, SEM and XRD analysis of ettringites and specific properties of some cement tested and of their pastes.The experimental results have also demonstrated that when 7.0% SO3, equivalent to 15.05% of gypsum, was added to the M pozzolan-containing Portland cement and tested with the ASTM C 452-68 method, it was not found to behave aggressively but rather as “setting regulator ”, because the increase in mechanical strengths over time and setting times in these mixes were, therefore, similar to the pattern observed in any PC. However, when the gypsum content was raised to triple than that amount (21.0% SO3, it behaved aggressively. In both cases, logically, ettringite from both origins were involved in the resulting beneficial or adverse behavior.En esta Parte II se utilizaron los mismos materiales cementíceos (CPO, CPRS, y metakaolín, MK, los mismos cementos de mezcla y el mismo método de ensayo ASTM C 452-68 que en la Parte I. Otras determinaciones complementarias fueron: análisis químico de los materiales cementíceos, análisis por DRX y SEM de ettringitas y propiedades específicas de algunos cementos ensayados y de sus pastas.Los resultados experimentales obtenidos han demostrado también que, el 7.0% de SO3 presente en los 30 cementos de mezcla con MK, ensayados conforme el método ASTM C 452-68, no se comporta como agresivo sino como ”regulador de fraguado”, porque los tiempos de fraguado y el aumento de resistencias mecánicas fueron como los de cualquier CP. De aquí que algunos de esos cementos de mezcla puedan ser considerados “cementos hidráulicos expansivos”, el resto, no. Sin embargo, cuando la cantidad de yeso aportada fue el triple (21,0% SO3, se comportó como agresivo, motivo por el cual

  17. Application of terrestrial laser scanner on tidal flat morphology at a typhoon event timescale

    Science.gov (United States)

    Xie, Weiming; He, Qing; Zhang, Keqi; Guo, Leicheng; Wang, Xianye; Shen, Jian; Cui, Zheng

    2017-09-01

    Quantification of tidal flat morphological changes at varying timescales is critical from a management point of view. High-resolution tidal flat morphology data, including those for mudflats and salt-marshes, are rare due to monitoring difficulty by traditional methods. Recent advances in Terrestrial Laser Scanner (TLS) technology allow rapid acquisition of high-resolution and large-scale morphological data, but it remains problematic for its application on salt-marshes due to the presence of dense vegetation. In this study, we applied a TLS system to retrieve high-accuracy digital elevation models in a tidal flat of the Yangtze Estuary by using a robust and accurate Progressive Morphological filter (PM) to separate ground and non-ground points. Validations against GPS-supported RTK measurements suggested remarkable performance. In this case the average estimation error was about 0.3 cm, while the Root Mean Square Error (RMSE) was 2.0 cm. We conducted three TLS surveys on the same field including salt-marshes and mudflats at the time points 5 days before, 3 days after, and 45 days after a typhoon event. The retrieved data showed that the mudflats suffered from profound erosion while the salt-marshes slightly accreted during the typhoon period. The average elevation change of the total area was about - 4 cm (- 0.28 cm per day). However, both the mudflats and salt-marshes deposited in the post-typhoon period and the accretion over salt-marshes occurred at a higher rate than that during the typhoon. The elevation of the total area increased by 15.9 cm (0.37 cm per day), suggesting fast recovery under calm conditions. Quantification of the erosion and deposition rates was aided by the high quality TLS data. This study shows the effectiveness of TLS in quantifying morphological changes of tidal flats at an event (and post-event) timescale. The data and analysis also provide sound evidence on vegetation impact in stimulating salt-marsh development and restoration

  18. Morphological changes in hard dental tissues prepared by Er:YAG laser (LiteTouch, Syneron), Carisolv and rotary instruments. A scanning electron microscopy evaluation.

    Science.gov (United States)

    Tsanova, Snejana Ts; Tomov, Georgi T

    2010-01-01

    This in vitro investigation aimed to study by means of scanning electron microscope the morphological changes in hard dental tissues after using several different methods for caries removal and cavity preparation. Twenty freshly extracted human teeth with carious lesions were used in the study. They were assigned to four groups depending on the method used for preparation: Group 1--Cavity preparation using Er: YAG laser (LiteTouch, Syneron, Israel). Group 2--Chemomechanical preparation using colourless Carisolv gel (MediTeam AB, Savedalen, Sweden). Group 3--Mechanical rotary preparation using diamond burs and air turbine. Group 4--Mechanical rotary preparation using by steel burs and micromotor. The preparations were performed strictly according to the manufacturer's instructions for proper use of instruments. The teeth samples were prepared for histological study and investigated by a scanning electron microscope at different magnification; the morphological changes in the tissues were registered and compared. There were considerable differences in the surface characteristics of the dental tissues when we analysed the photomicrographs of the specimens obtained using scanning electron microscopy (SEM). The surface after laser treatment remained highly retentive with no residual smear layer; the second best results in this respect were registered when teeth were chemomechanically excavated with Carisolv gel. The mechanical methods of cavity preparation resulted in surfaces with a smear layer of dentin without any microretentions. The scanning electron microscopy of hard dental tissues prepared using steel and diamond burs showed surfaces covered with a thick smear layer that may be relevant to the subsequent bonding of adhesive restorative materials to the prepared cavity. In preparing the surface using a turbine with diamond burs the smear layer was thinner and part of the dentinal tubules orifices were open in the area of water turbulence. SEM analysis of hard

  19. Structural and morphological properties of metallic thin films grown by pulsed laser deposition for photocathode application

    Science.gov (United States)

    Lorusso, A.; Gontad, F.; Caricato, A. P.; Chiadroni, E.; Broitman, E.; Perrone, A.

    2016-03-01

    In this work yttrium and lead thin films have been deposited by pulsed laser deposition technique and characterized by ex situ different diagnostic methods. All the films were adherent to the substrates and revealed a polycrystalline structure. Y films were uniform with a very low roughness and droplet density, while Pb thin films were characterized by a grain morphology with a relatively high roughness and droplet density. Such metallic materials are studied because they are proposed as a good alternative to copper and niobium photocathodes which are generally used in radiofrequency and superconducting radiofrequency guns, respectively. The photoemission performances of the photocathodes based on Y and Pb thin films have been also studied and discussed.

  20. Influence of effective number of pulses on the morphological structure of teeth and bovine femur after femtosecond laser ablation.

    Science.gov (United States)

    Nicolodelli, Gustavo; Lizarelli, Rosane de Fátima Zanirato; Bagnato, Vanderlei Salvador

    2012-04-01

    Femtosecond lasers have been widely used in laser surgery as an instrument for contact-free tissue removal of hard dental, restorative materials, and osseous tissues, complementing conventional drilling or cutting tools. In order to obtain a laser system that provides an ablation efficiency comparable to mechanical instruments, the laser pulse rate must be maximal without causing thermal damage. The aim of this study was to compare the different morphological characteristics of the hard tissue after exposure to lasers operating in the femtosecond pulse regime. Two different kinds of samples were irradiated: dentin from human extracted teeth and bovine femur samples. Different procedures were applied, while paying special care to preserving the structures. The incubation factor S was calculated to be 0.788±0.004 for the bovine femur bone. These results indicate that the incubation effect is still substantial during the femtosecond laser ablation of hard tissues. The plasma-induced ablation has reduced side effects, i.e., we observe less thermal and mechanical damage when using a superficial femtosecond laser irradiation close to the threshold conditions. In the femtosecond regime, the morphology characteristics of the cavity were strongly influenced by the change of the effective number of pulses.

  1. Morphology, microstructure, and mechanical properties of laser-welded joints in GH909 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chunming; Cai, Yuanzheng; Hu, Chongjing; Zhang, Xiong; Yan, Fei; Hu, Xiyuan [Huazhong University of Science and Technology, Wuhan (China)

    2017-05-15

    The experimental laser welding of GH909 alloy was conducted in this study. The morphology, microstructure, and mechanical properties of laser-welded joints were analyzed by scanning electron microscopy, energy diffraction spectroscopy, and other techniques. Results revealed that the microstructure of the welded joints mainly consisted of tiny cellular structures, dendritic structures, and equiaxed crystals. Pores appeared in the interdendritic regions because of the insufficient local feeding of molten metal during solidification. Nb segregation in the heat-affected zone caused liquation cracking, whereas C segregation further induced the formation of carbide precipitates along the grain boundaries during the welding thermal cycle. The instability of the keyhole significantly promoted the escape of the metal vapor/plasma from the hole; as a result, porosity defects formed in the weld. The average tensile strength of the test joints was 756 MPa, which is 93.1 % of that of the base metal. The average microhardness of the weld zone (250 HV) was higher than that of the GH909 alloy substrate (208 HV), peaking at 267 HV. Microcracks appeared along the grain boundaries, proving that the grain boundaries were the weakest areas in the joint.

  2. Morphological study of adult male worms of Schistosoma mansoni Sambon, 1907 by confocal laser scanning microscopy

    Directory of Open Access Journals (Sweden)

    Machado-Silva José Roberto

    1998-01-01

    Full Text Available Aiming to detail data obtained through brightfield microscopy (BM on reproductive, excretory and digestive system, specimens of Schistosoma mansoni eight weeks old, were recovered from SW mice, stained with Langeron's carmine and analyzed under a confocal laser scanning microscope CLSM 410 (Carl Zeiss. The reproductive system presented a single and lobate testis, with intercommunications between the lobes without efferent duct. Supernumerary testicular lobe was amorphous and isolated from the normal ones. Collecting tubules (excretory ducts, followed by the excretory bladder, opening to the external media through the excretory pore, were observed at the posterior extremity of the body. In the digestive tract, a cecal swelling was noted at the junction that originates the single cecum. It was concluded that through confocal laser scanning microscopy, new interpretations of morphological structures of S. mansoni worms could be achieved, modifying adopted and current descriptions. The gonad consists of a single lobed testis, similar to that observed in some trematode species. Moreover, the same specimens can be observed either by BM or CLSM, considering that the latter causes only focal and limited damage in tissue structures.

  3. Surface morphology of polyethylene glycol films produced by matrix-assisted pulsed laser evaporation (MAPLE): Dependence on substrate temperature

    DEFF Research Database (Denmark)

    Rodrigo, K.; Czuba, P.; Toftmann, B.;

    2006-01-01

    The dependence of the surface morphology on the substrate temperature during film deposition was investigated for polyethylene glycol (PEG) films by matrix-assisted pulsed laser evaporation (MAPLE). The surface structure was studied with a combined technique of optical imaging and AFM measurements...

  4. Effects of Laser Energy Density on Size and Morphology of NiO Nanoparticles Prepared by Pulsed Laser Ablation in Liquid

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Rory; Reddy, M. Amaranatha; Kim, Tae Kyu [Pusan National University, Busan (Korea, Republic of)

    2015-01-15

    Metaloxide nanoparticles are of great importance to a large variety of chemical and material applications ranging from catalysts to electronic devices. Among the metal-oxide nanoparticles, NiO is one of the technologically versatile and important semiconducting materials. It has been extensively investigated because of its myriad applications in catalysts, gas sensors, Li-ion battery materials, electrochromic coatings, active optical fibers, fuel cell electrodes, and so on. The effect of laser ablation at various laser energy densities was investigated. At low energy densities, the produced nanoparticles were of irregular morphology with an average size of 2.4 nm. At higher laser energy densities, the produced nanoparticles were spherical, with a polycrystalline structure and their average size was around 10 nm. More detailed investigations on effects of laser wavelength and energy density as well as the particle size effect on the catalytic activity of synthesized NiO nanoparticles will be investigated in future works.

  5. Morphology alterations of skin and subcutaneous fat at NIR laser irradiation combined with delivery of encapsulated indocyanine green

    Science.gov (United States)

    Yanina, Irina Yu.; Navolokin, Nikita A.; Svenskaya, Yulia I.; Bucharskaya, Alla B.; Maslyakova, Galina N.; Gorin, Dmitry A.; Sukhorukov, Gleb B.; Tuchin, Valery V.

    2017-05-01

    The goal of this study is to quantify the impact of the in vivo photochemical treatment of rats with obesity using indocyanine green (ICG) dissolved in saline or dispersed in an encapsulated form at NIR laser irradiation, which was monitored by tissue sampling and histochemistry. The subcutaneous injection of the ICG solution or ICG encapsulated into polyelectrolyte microcapsules, followed by diode laser irradiation (808 nm, 8 W/cm2, 1 min), resulted in substantial differences in lipolysis of subcutaneous fat. Most of the morphology alterations occurred in response to the laser irradiation if a free-ICG solution had been injected. In such conditions, membrane disruption, stretching, and even delamination in some cases were observed for a number of cells. The encapsulated ICG aroused similar morphology changes but with weakly expressed adipocyte destruction under the laser irradiation. The Cochran Q test rendered the difference between the treatment alternatives statistically significant. By this means, laser treatment using the encapsulated form of ICG seems more promising and could be used for safe layerwise laser treatment of obesity and cellulite.

  6. Morphological evaluation of cavity preparation surface after duraphat and Er:YAG laser treatment by scanning electronic microscopy; Avaliacao das alteracoes morfologicas da superficie do preparo cavitario apos condicionamento com verniz fluoretado a 2,26 % e laser de Er:YAG atraves de microscopia eletronica de varredura

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Luciane Borelli

    2002-07-01

    The treatment of dental surface using different lasers to prevent dental caries has been studied for several on last years. The purpose of this in vitro study was to evaluate the morphological changes on dentin surface from pulpal wall of cavity preparations performed by high-speed drill, treated with 2,26% fluoride varnish (Duraphat) and Er:YAG laser, and then submitted after receiving or not to EDTA 15% treatment. Twenty Class V cavities were performed on ten humans molars. The specimens were randomly divided in to 4 groups: group 1- treatment with Duraphat followed by Er:YAG laser irradiation (120 mJ/ 4 Hz); group 2: Er:YAG laser irradiation, same parameters, followed by Duraphat treatment; group 3- same group 1 followed by immersion in EDTA (5 min); group 4 - same as group 2 followed by immersion in EDTA (5 min). The specimens were processed for SEM analysis. The micrographs showed that Duraphat treatment promoted morphological changes on dentin, closing dentinal tubules; the specimens treated by Duraphat and Er:YAG laser and immersed in EDTA (group 3) showed homogeneous surface, closed and protected dentinal tubules, maintenance of the fluoride varnish on the dentin surface and around the dentinal tubules, showing feasible and efficiency of these therapies the feasibility.(author)

  7. Testing relativity again, laser, laser, laser, laser

    NARCIS (Netherlands)

    Einstein, A.

    2015-01-01

    laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser,

  8. Study in vitro of dental enamel irradiated with a high power diode laser operating at 960 nm: morphological analysis of post-irradiation dental surface and thermal effect analysis in pulp chamber due to laser application; Estudo in vitro do esmalte dental irradiado com laser de diodo de alta potencia em 960 nm: analise morfologica da superficie dental pos-irradiada e analise do comportamento termico na camara pulpar devido a aplicacao laser

    Energy Technology Data Exchange (ETDEWEB)

    Quinto Junior, Jose

    2001-07-01

    Objectives: This study examines the structural and thermal modifications induced in dental enamel under dye assisted diode laser irradiation. The aim of this study is to verify if this laser-assisted treatment is capable to modify the enamel surface by causing fusion of the enamel surface layer. At the same time, the pulpal temperature rise must be kept low enough in order not to cause pulpar necrosis. To achieve this target, it is necessary to determine suitable laser parameters. As is known, fusion of the enamel surface followed by re-solidification produce a more acid resistant layer. This surface treatment is being researched as a new method for caries prevention. Method and Materials: A series of fourteen identically prepared enamel samples of human teeth were irradiated with a high power diode laser operating at 960 nm and using fiber delivery. Prior to irradiation, a fine layer of cromophorous ink was applied to the enamel surface. In the first part of the experiment the best parameter for pulse duration was determined. In the second part of the experimental phase the same energy density was used but with different repetition rates. During irradiation we monitored the temperature rise in the pulpal cavity. The morphology of the treated samples was analysed under SEM. Results: The morphology of the treated samples showed a homogeneously re-solidified enamel layer. The results of the temperature analysis showed a decrease of the pulpal temperature rise with decreasing repetition rate. Conclusion: With the diode laser it is possible to cause morphological alterations of the enamel surface, which is known to increase the enamel resistance against acid attack, and still maintain the temperature rise in the pulpar chamber below damage threshold. (author)

  9. Morphological Changes Along a Dike Landside Slope Sampled by 4d High Resolution Terrestrial Laser Scanning

    Science.gov (United States)

    Herrero-Huertaa, Mónica; Lindenbergh, Roderik; Ponsioen, Luc; van Damme, Myron

    2016-06-01

    Emergence of light detection and ranging (LiDAR) technology provides new tools for geomorphologic studies improving spatial and temporal resolution of data sampling hydrogeological instability phenomena. Specifically, terrestrial laser scanning (TLS) collects high resolution 3D point clouds allowing more accurate monitoring of erosion rates and processes, and thus, quantify the geomorphologic change on vertical landforms like dike landside slopes. Even so, TLS captures observations rapidly and automatically but unselectively. In this research, we demonstrate the potential of TLS for morphological change detection, profile creation and time series analysis in an emergency simulation for characterizing and monitoring slope movements in a dike. The experiment was performed near Schellebelle (Belgium) in November 2015, using a Leica Scan Station C10. Wave overtopping and overflow over a dike were simulated whereby the loading conditions were incrementally increased and 14 successful scans were performed. The aim of the present study is to analyse short-term morphological dynamic processes and the spatial distribution of erosion and deposition areas along a dike landside slope. As a result, we are able to quantify the eroded material coming from the impact on the terrain induced by wave overtopping which caused the dike failure in a few minutes in normal storm scenarios (Q = 25 l/s/m) as 1.24 m3. As this shows that the amount of erosion is measurable using close range techniques; the amount and rate of erosion could be monitored to predict dike collapse in emergency situation. The results confirm the feasibility of the proposed methodology, providing scalability to a comprehensive analysis over a large extension of a dike (tens of meters).

  10. Terrestrial Laser Scanning of Peatland Surface Morphology for Eco-Hydrological Applications

    Science.gov (United States)

    Anderson, Karen; Bennie, Jonathan; Wetherelt, Andrew

    2010-05-01

    point clouds permitted measurement of the typical grain sizes of peatland structures, and allowed us to capture the texture and length-scale of hummock-hollow topography, shrub canopy and peatland morphological features. Results demonstrate, for the first time, the advantages of laser scanning methodologies for rapid measurement of 3-dimensional vegetation canopy structure and surface microtopography, at fine spatial scales, in short vegetation. We demonstrate how adoption of such approaches can provide quantitative, spatial data for description of peatland structure, which is inherently linked to eco-hydrological function. SUMMARY OF KEY FINDINGS: Specifically, our results show: (a) The spatial scale (grain size) of vegetation patterning and microtopography in peatland systems. We demonstrate that intact plots on the peat dome with hummock-hollow topography have a distinctive fine-scale isotropic pattern with a range of <1 m. drained plots, where hummock-hollow microtopes are reduced show lower semivariance at this lag. (b) The optimal spatial resolution for surveying changes in vegetation pattern and structure on peatlands. The study suggests that scaling up the method proposed here to airborne LiDAR is plausible. Other work following this project has already investigated this potential and brief results will be shown.

  11. Experimental investigation and 3D-simulation of the ablated morphology of titanium surface using femtosecond laser pulses

    Science.gov (United States)

    Liu, Dong; Chen, Chuansong; Man, Baoyuan; Meng, Xue; Sun, Yanna; Li, Feifei

    2015-12-01

    The femtosecond laser ablated morphology on titanium surface is investigated theoretically and experimentally. A three dimensional two temperature model (3D-TTM) is used to simulate the surface morphology of titanium sample which is irradiated by femtosecond laser pulses. The electron heat capacity and electron-phonon coupling coefficient of titanium (transition metal) are complex temperature dependent, so the two parameters are corrected based on the theory of electron density of states (DOS). The model is solved by the finite difference time domain (FDTD) method. The 3D temperature field near the target surface is achieved. The radius and depth of the ablated crater are obtained based on the temperature field. The evolutions of the crate's radius and depth with laser fluence are discussed and compared with the experimental results. It is found that the back-flow of the molten material and the deposition of the material vapor should be responsible for the little discrepancy between the simulated and experimental results. The present work makes a better understanding of the thermodynamic process of femtosecond laser ablating metal and meanwhile provides an effective method tool to predict the micro manufacturing process on metals with femtosecond laser.

  12. Analysis of morphology and residual porosity in selective laser melting of Fe powders using single track experiments

    Science.gov (United States)

    Shutov, I. V.; Gordeev, G. A.; Kharanzhevskiy, E. V.; Krivilyov, M. D.

    2017-04-01

    Morphology and residual porosity of single tracks obtained by pulse selective laser melting (SLM) of Fe powder have been studied by metallography. Multiple cross sections of the stainless substrate with the single tracks deposited by SLM are examined and classified depending on processing parameters. A sustainable scanning strategy to reduce residual porosity is suggested for pulse laser annealing. The developed method is suitable both for improvement of processing regimes in commercial SLM machines and validation of numerical models in additive manufacturing of metal parts. The effect of the beam radius, pulse energy, its frequency and duration on a shape of the single track and its adhesion to the substrate is revealed.

  13. Morphology and structural studies of WO3 films deposited on SrTiO3 by pulsed laser deposition

    Science.gov (United States)

    Kalhori, Hossein; Porter, Stephen B.; Esmaeily, Amir Sajjad; Coey, Michael; Ranjbar, Mehdi; Salamati, Hadi

    2016-12-01

    WO3 films have been grown by pulsed laser deposition on SrTiO3 (001) substrates. The effects of substrate temperature, oxygen partial pressure and energy fluence of the laser beam on the physical properties of the films were studied. Reflection high-energy electron diffraction (RHEED) patterns during and after growth were used to determine the surface structure and morphology. The chemical composition and crystalline phases were obtained by XPS and XRD respectively. AFM results showed that the roughness and skewness of the films depend on the substrate temperature during deposition. Optimal conditions were determined for the growth of the highly oriented films.

  14. Morphological Changes Of The Root Surface And Fracture Resistance After Treatment Of Root Fracture By CO2 Laser And Glass Ionomer Or Mineral Trioxide Aggregates

    Science.gov (United States)

    Badr, Y. A.; Abd El-Gawad, L. M.; Ghaith, M. E.

    2009-09-01

    This in vitro study evaluates the morphological changes of the root surface and fracture resistance after treatment of root cracks by CO2 laser and glass Ionomer or mineral trioxide aggregates (MTA). Fifty freshly extracted human maxillary central incisor teeth with similar dimension were selected. Crowns were sectioned at the cemento-enamel junction, and the lengths of the roots were adjusted to 13 mm. A longitudinal groove with a dimension of 1×5 mm2 and a depth of 1.5 mm was prepared by a high speed fissure bur on the labial surface of the root. The roots were divided into 5 groups: the 10 root grooves in group 1 were remained unfilled and were used as a control group. The 10 root grooves in group 2 were filled with glass Ionomer, 10 root grooves in group 3 were filled with MTA, the 10 root grooves in group 4 were filled with glass Ionomer and irradiated by CO2 laser and the 10 root grooves in group 5 were filled with MTA and irradiated with CO2 laser. Scanning electron microscopy was performed for two samples in each group. Tests for fracture strength were performed using a universal testing machine and a round tip of a diameter of 4 mm. The force was applied vertically with a constant speed of 1 mm min 1. For each root, the force at the time of fracture was recorded in Newtons. Results were evaluated statistically with ANOVA and Turkey's Honestly Significant Difference (HSD) tests. SEM micrographs revealed that the melted masses and the plate-like crystals formed a tight Chemical bond between the cementum and glass Ionomer and melted masses and globular like structure between cementum and MTA. The mean fracture resistance was the maximum fracture resistance in group 5 (810.8 N). Glass Ionomer and MTA with the help of CO2 laser can be an alternative to the treatment of tooth crack or fracture. CO2 laser increase the resistance of the teeth to fracture.

  15. SEM observation on external morphology of Caloglyphus berlesei (Acari:Astigmata: Acaridae) at different developmental stages%伯氏嗜木螨各发育阶段的外部形态扫描电镜观察

    Institute of Scientific and Technical Information of China (English)

    李朝品; 姜玉新; 刘婷; 郭伟; 王少圣; 陈琪

    2013-01-01

    [目的]观察伯氏嗜木螨Caloglyphus berlesei生活史各发育阶段外部形态和超微形态特征.[方法]采集中华地鳖Eupolyphaga sinensis培养床上的培养料,分离伯氏嗜木螨.将分离获得的伯氏嗜木螨双蒸水洗涤后,一部分用于制备常规玻片标本,光镜下直接观察;另一部分用2.5%戊二醛溶液固定,70%酒精再次洗涤,临界点干燥,置于扫描电镜下观察不同发育阶段(包括卵、幼螨、若螨及成螨)的超微形态特征.[结果]电镜下伯氏嗜木螨各发育阶段的足、刚毛和外生殖器及其附属结构的形态均清晰可辨.幼螨足3对,足上无叶状刚毛,基节干发达;若螨足4对,出现第4背毛,生殖区发育不全;休眠体足爪和前跗节发达,出现叶状毛、胫节毛及膝节毛等结构,生殖板骨化明显,其两侧有吸盘和刚毛各1对.吸盘板上共有4对成对的吸盘、1个单吸盘和2对类圆形微凸.成螨生殖感觉器骨化且呈心形,雄雌成螨生殖感觉器的刚毛数量上有明显差异.[结论]对伯氏嗜木螨形态和超微形态特征的观察有助于对其进一步科学分类和进行生活史研究,并可为控制伯氏嗜木螨及其引起的过敏性疾病提供参考.%To observe the morphological changes of the live Caloglyphus berlesei and the ultra-structure under scanning electron microscope (SEM) at different developmental stages. [Methods] C. berlesei specimens were isolated from the bed feedsduff in an Eupolyphaga sinensis breeding farm, and rinsed with double distilled water. One portion of the isolations were used for slide preparation in the conventional manner and immediately observed under light microscope, and the other was fixed with 2.5% glutaraldehyde solution and washed once again with 75% alcohol. By critical-point drying, the specimens were observed under SEM for the ultrastructure characteristics at different developmental stages including egg, larva, nymph and adult. [Results] Morphological

  16. Effect of electric field distribution on the morphologies of laser-induced damage in hafnia-silica multilayer polarizers

    Energy Technology Data Exchange (ETDEWEB)

    Genin, F.Y.; Stolz, C.J.; Reitter, T.; Kozlowski, M.R. [Lawrence Livermore National Lab., CA (United States); Bevis, R.P.; vonGunten, M.K. [Spectra-Physics Lasers, Inc., Mountain View, CA (United States)

    1997-01-01

    Hafnia-silica multilayer polarizers were deposited by e-beam evaporation onto BK7 glass substrates. The polarizers were designed to operate at 1064 nm at Brewster`s angle (56{degree}). They were tested with a 3-ns laser pulse at 45, 56, and 65{degree} incidence angle in order to vary the electric field distribution in the multilayer, study their effects on damage morphology, and investigate possible advantages of off-use angle laser conditioning. Morphology of the laser-induced damage was characterized by optical and scanning electron microscopy. Four distinct damage morphologies (pit, flat bottom pit, scald, outer layer delamination) were observed; they depend strongly on incident angle of the laser beam. Massive delamination observed at 45 and 56{degree} incidence, did not occur at 65{degree}; instead, large and deep pits were found at 65{degree}. Electric field distribution, temperature rise, and change in stress in the multilayer were calculated to attempt to better understand the relation between damage morphology, electric field peak locations, and maximum thermal stress gradients. The calculations showed a twofold increase in stress change in the hafnia top layers depending on incident angle. Stress gradient in the first hafnia-silica interface was found to be highest for 45, 56, and 65{degree}, respectively. Finally, the maximum stress was deeper in the multilayer at 65{degree}. Although the limitations of such simple thermal mechanical model are obvious, the results can explain that outer layer delamination is more likely at 45 and 56{degree} than 65{degree} and that damage sites are expected to be deeper at 65{degree}.

  17. Fs-laser processing of polydimethylsiloxane

    Energy Technology Data Exchange (ETDEWEB)

    Atanasov, Petar A., E-mail: paatanas@ie.bas.bg; Nedyalkov, Nikolay N. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Shose, Sofia 1784 (Bulgaria); Valova, Eugenia I.; Georgieva, Zhenya S.; Armyanov, Stefan A.; Kolev, Konstantin N. [Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria); Amoruso, Salvatore; Wang, Xuan; Bruzzese, Ricardo [CNR-SPIN, Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Sawczak, Miroslaw; Śliwiński, Gerard [Photophysics Department, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St, 80-231 Gdańsk (Poland)

    2014-07-14

    We present an experimental analysis on surface structuring of polydimethylsiloxane films with UV (263 nm) femtosecond laser pulses, in air. Laser processed areas are analyzed by optical microscopy, SEM, and μ-Raman spectroscopy. The laser-treated sample shows the formation of a randomly nanostructured surface morphology. μ-Raman spectra, carried out at both 514 and 785 nm excitation wavelengths, prior and after laser treatment allow evidencing the changes in the sample structure. The influence of the laser fluence on the surface morphology is studied. Finally, successful electro-less metallization of the laser-processed sample is achieved, even after several months from the laser-treatment contrary to previous observation with nanosecond pulses. Our findings address the effectiveness of fs-laser treatment and chemical metallization of polydimethylsiloxane films with perspective technological interest in micro-fabrication devices for MEMS and nano-electromechanical systems.

  18. Influence of the incidence angle on the morphology of enamel and dentin under Er:YAG laser irradiation; Estudo da influencia da angulacao do feixe laser na morfologia de esmalte e dentina irradiados com laser de Er:YAG

    Energy Technology Data Exchange (ETDEWEB)

    Junqueira Junior, Duilio Naves

    2002-07-01

    The purpose of this study is to make an in vitro evaluation, using scanning electron microscopy, of the influence of the laser beam irradiation angle on the enamel and dentin morphology. These tissues were both irradiated by Er:YAG Laser, with the same energy parameter. Twenty-four incisive bovine teeth were used, separated in eight groups, four of enamel, and four of dentin, with three specimens in each group. Each specimen was submitted to three laser applications, varying the incidence angle, between the laser and the tooth surface, at 90, 50 and 20 degrees. The applied frequency was 2 Hz, with 20 pulses in each application. The KaVo Key Laser 3 was employed, wavelength at 2940 nm, adjustable energy from 40 to 600 mJ and repetition rate from 1 to 25 Hz. The groups were distributed according to the energy parameter as follows - enamel: 250 mJ; 300 mJ; 350 mJ and 400 mJ; dentin: 200 mJ; 250 mJ; 300 mJ and 350 mJ. The results evidenced the Laser incidence angle importance; it is an essential parameter in the protocol of utilization and it should not be disregarded. The observations of this study allow to conclude that the Laser incidence angle has direct influence on the morphological aspect of the alterations produced in enamel and dentin. (author)

  19. Comparing efficiency and root surface morphology after scaling with Er:YAG and Er,Cr:YSGG lasers.

    Science.gov (United States)

    Etemadi, Ardavan; Sadeghi, Mostafa; Abbas, Fatemeh Mashhadi; Razavi, Fahime; Aoki, Akira; Azad, Reza Fekr; Chiniforush, Nasim

    2013-01-01

    The purpose of this study was to investigate the root morphology of teeth and efficiency of scaling after using Er:YAG and Er,Cr:YSGG lasers. Thirty-two periodontally hopeless teeth were extracted. The border of an appropriate calculus was marked using a diamond bur on each tooth, and the calculus was divided into two almost equal parts. An Er,Cr:YSGG laser with pulse energy of 50 mJ, power of 1 W, and energy density of 17.7 J/cm2 and an Er:YAG laser with pulse energy of 200 mJ, power of 2.4 W, and energy density of 21 J/cm2 were used to remove the calculus. The time for scaling was recorded for each group, and using stereomicroscopic analysis, the calculus remnant, carbonization, and number of craters were investigated. The mean time required for calculus removal in the Er,Cr:YSGG and Er:YAG laser groups was 15.22 ± 6.18 seconds and 7.12 ± 4.11 seconds, respectively. The efficiency of calculus removal in the Er:YAG laser group was significantly higher than in the Er,Cr:YSGG laser group. Under stereomicroscope examination, no carbonization or remaining calculus was found in samples from either group, but all samples had craters. The number of craters in the Er,Cr:YSGG laser group was significantly higher than in the Er:YAG laser group. According to the parameters used and limitations of this study, there was no significant difference in efficiency per power for calculus removal between the two groups.

  20. Secondary Austenite Morphologies in Fusion Zone of Welded Joint after Postweld Heat Treatment with a Continuous Wave Laser

    Institute of Scientific and Technical Information of China (English)

    Heping Liu; Xuejun Jin

    2012-01-01

    In order to improve the weldability of duplex stainless steels,obtaining more secondary austenite in the weld metal is an effective way.Therefore,optimizing the secondary austenite by changing its morphology,volume fraction and stability may be expected to enhance the ductility of the weld.The secondary austenite morphologies in the fusion zone of the laser continuously heat treated welds of 2205 duplex stainless steel were investigated.The secondary austenite morphologies were found to be influenced by different laser power level.The secondary austenite with penniform,freely grown and dendritic shape appeared in the course of 4,6 and 8 kW continuous heat treatment,respectively.It was found that there were three kinds of morphologies of secondary austenite in the fusion zone treated by different power,i.e.,widmannst¨atten austenite,grain boundary austenite and intragranular austenite.The results demonstrated that the mechanism of the secondary austenite formation was a displacement mechanism during the initial austenite lath formation and a diffusion mechanism during cooling.The nitrides provided the nitrogen for the transformation and at the same time acted as nucleation sites for the secondary austenite.

  1. Morphology control of laser-induced periodic surface structure on the surface of nickel by femtosecond laser

    Institute of Scientific and Technical Information of China (English)

    Fantong Meng; Jie Hu; Weina Han; Penjun Liu; Qingsong Wang

    2015-01-01

    An interesting transition between low spatial frequency laser-induced periodic surface structure (LIPSS) and high spatial frequency LIPSS (HSFL) on the surface of nickel is revealed by changing the scanning speed and the laser fluence.The experimental results show the proportion of HSFL area in the overall LIPSS (i.e.,K) presents a quasi-parabola function trend with the polarization orientation under a femtosecond (fs) laser single-pulse train.Moreover,an obvious fluctuation dependence of K on the pulse delay is observed under a fs laser dual-pulse train.The peak value of the fluctuation is found to be determined by the polarization orientation of the dual-pulse train.

  2. SEM microcharacterization of semiconductors

    CERN Document Server

    Holt, D B

    1989-01-01

    Applications of SEM techniques of microcharacterization have proliferated to cover every type of material and virtually every branch of science and technology. This book emphasizes the fundamental physical principles. The first section deals with the foundation of microcharacterization in electron beam instruments and the second deals with the interpretation of the information obtained in the main operating modes of a scanning electron microscope.

  3. Morphology and phase structures of CW laser-induced oxide layers on iron surface with evolving reflectivity and colors

    Science.gov (United States)

    Wu, Taotao; Wang, Lijun; Wei, Chenghua; Zhou, Menglian; He, Minbo; Wu, Lixiong

    2016-11-01

    Laser-induced oxidation will change the laser reflectivity and color features of metal surface. Both changes can be theoretically calculated based on the oxidation kinetics and the optical constants of oxides. For the purpose of calculation, the laser-induced oxidation process of pure polycrystalline iron was studied. Samples with various color features were obtained by continuous wave Nd:YAG fiber laser (1.06 μm) irradiation depending on progressive durations in the intensity of 1.90 W/cm2. The real-time reflectivity and temperature were measured with integral sphere and thermocouples. The irradiated surface morphology and phase structures were characterized by microscope, X-ray diffraction and Raman spectrum. It was found that the first formed magnetite made the surface reflectivity decline rapidly and caused the "positive feedback" effect because of molecular absorption. The later formed hematite oscillated the reflectivity by interference effect. The oxide films were thin, orientated and badly crystallized. The oxidation process was influenced by the grain orientation of the metal substrate. These results made the mechanism of laser-induced oxidation of iron clear and provided available experimental data for accurate modeling of the oxidation kinetics.

  4. Effect of nanosecond pulse laser ablation on the surface morphology of Zr-based metallic glass

    Science.gov (United States)

    Zhu, Yunhu; Fu, Jie; Zheng, Chao; Ji, Zhong

    2016-09-01

    In this study, we investigated the ripple patterns formation on the surface of Zr41.2Ti13.8Cu12.5Ni10Be22.5 (vit1) bulk metallic glass using a nanosecond pulse laser ablation in air with a wavelength of 1064 nm. The strong thermal ablation phenomenon could be observed on vit1 BMG surface at laser energy of 200 mJ as a result of the adhibition of confining overlay. Many periodic ripples had formed on the edge of the ablated area at laser energy of 400 mJ because of the high intensity pulsed laser beam. The underlying mechanism of the periodic ripples formation could be explained by the K-H hydrodynamic instability theory. It had been shown that laser ablation with 600 mJ and 200 pulses results in the formation of many micro-cracks on the ablated area. Further analysis showed that the spatial occupation of the laser ablated area and the spacing between two adjacent ripples increased as the laser energy and the number of incident laser pulses increasing. The surface ripples feature on the edge of ablated area became more obvious with increasing laser pulses, but it was not correlated closely with the laser energies variation.

  5. Space Experiment Module (SEM)

    Science.gov (United States)

    Brodell, Charles L.

    1999-01-01

    The Space Experiment Module (SEM) Program is an education initiative sponsored by the National Aeronautics and Space Administration (NASA) Shuttle Small Payloads Project. The program provides nationwide educational access to space for Kindergarten through University level students. The SEM program focuses on the science of zero-gravity and microgravity. Within the program, NASA provides small containers or "modules" for students to fly experiments on the Space Shuttle. The experiments are created, designed, built, and implemented by students with teacher and/or mentor guidance. Student experiment modules are flown in a "carrier" which resides in the cargo bay of the Space Shuttle. The carrier supplies power to, and the means to control and collect data from each experiment.

  6. Dynamics of double-pulse laser produced titanium plasma inferred from thin film morphology and optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krstulović, N., E-mail: niksak@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Salamon, K., E-mail: ksalamon@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Modic, M., E-mail: martina.modic@ijs.si [Jožef Stefan Institute, Jamova 39, 1001 Ljubljana (Slovenia); Bišćan, M., E-mail: mbiscan@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Milat, O., E-mail: milat@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Milošević, S., E-mail: slobodan@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia)

    2015-05-01

    In this paper, dynamics of double-pulse laser produced titanium plasma was studied both directly using optical emission spectroscopy (OES) and indirectly from morphological properties of deposited thin films. Both approaches yield consistent results. Ablated material was deposited in a form of thin film on the Si substrate. During deposition, plasma dynamics was monitored using optical emission spectroscopy with spatial and temporal resolutions. The influence of ablation mode (single and double) and delay time τ (delay between first and second pulses in double-pulse mode) on plasma dynamics and consequently on morphology of deposited Ti-films was studied using X-ray reflectivity and atomic force microscopy. Delay time τ was varied from 170 ns to 4 μs. The results show strong dependence of both emission signal and Ti-film properties, such as thickness, density and roughness, on τ. In addition, correlation of average density and thickness of film is observed. These results are discussed in terms of dependency of angular distribution and kinetic energy of plasma plume particles on τ. Advantages of using double-pulse laser deposition for possible application in thin film production are shown. - Highlights: • Ti-thin films produced by single and double pulse laser ablation mode. • Ablation mode and delay time influenced plasma plume and film characteristics. • Films are most compact for optimized delay time (thinnest, smoothest and most dense). • Plasma dynamics can be inferred from film characteristics.

  7. Determination of aggregate morphological properties using laser and their effects on rutting of asphalt mixes

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2013-11-01

    Full Text Available properties affecting pavement performance. The 3-D laser technology has been used in medical healthcare for many years to visualise shapes and surface characteristics of dental and orthopaedic structures. The laser device has been calibrated by the CSIR...

  8. Functional properties of laser effects on morphology of liver, gall bladder and bile ducts in cholelithiasis

    Directory of Open Access Journals (Sweden)

    Bakhtior Shamirzaev

    2012-05-01

    Full Text Available In 85 patients with calculous cholecystitis the preoperative preparation before laparoscopic cholecystectomy included irradiation of the area of gall bladder and epigastric puncture with low power magneto-infrared laser. The investigations performed revealed significant reduction of the liver and gall bladder changes both on the light optic and electron microscopic levels due to effects of low power laser irradiation.

  9. [Morphological and histochemical effects of subthreshold laser therapy on the chorioretinal complex].

    Science.gov (United States)

    Fedoruk, N A; Fedorov, A A; Bol'shunov, A V

    2013-01-01

    A variety of subthreshold laser methods that enable selective and precise treatment of chorioretinal microstructures, thus decreasing the risk of negative changes in retina and choriocapillaries, is used in current ophthalmological practice. This comparative pathomorphological and histochemical study allowed characterizing structural changes and functional activity of chorioretinal cells after application of different subthreshold laser technologies.

  10. Functional properties of laser effects on morphology of liver, gall bladder and bile ducts in cholelithiasis

    OpenAIRE

    Bakhtior Shamirzaev

    2012-01-01

    In 85 patients with calculous cholecystitis the preoperative preparation before laparoscopic cholecystectomy included irradiation of the area of gall bladder and epigastric puncture with low power magneto-infrared laser. The investigations performed revealed significant reduction of the liver and gall bladder changes both on the light optic and electron microscopic levels due to effects of low power laser irradiation.

  11. Surface morphology of thin lysozyme films produced by matrix-assisted pulsed laser evaporation (MAPLE)

    DEFF Research Database (Denmark)

    Purice, Andreea; Schou, Jørgen; Pryds, Nini;

    2007-01-01

    Thin films of the protein, lysozyme, have been deposited by the matrix-assisted pulsed laser evaporation (MAPLE) technique. Frozen targets of 0.3-1.0 wt.% lysozyme dissolved in ultrapure water were irradiated by laser light at 355 mn with a fluence of 2 J/cm(2). The surface quality of the thin ly...

  12. Morphologic and histopathologic changes in the rabbit cornea produced by femtosecond laser-assisted multilayer intrastromal ablation.

    Science.gov (United States)

    Zhang, Zhen-Yong; Chu, Ren-Yuan; Zhou, Xing-Tao; Dai, Jin-Hui; Sun, Xing-Huai; Hoffman, Matthew R; Zhang, Xing-Ru

    2009-05-01

    To observe morphologic and histopathologic changes in the midperiphery of the rabbit cornea produced by femtosecond laser-assisted multilayer intrastromal ablation, determine whether this method may be used to correct myopia, and study how the cornea heals when the epithelium is not injured. The right eyes of 10 New Zealand White rabbits were used for the experiments. A 60-kHz femtosecond laser delivery system was used, and three lamellar layers of laser pulses were focused starting at a corneal depth of 180 microm and ending at 90 microm from the surface, with each successive layer placed 45 microm anterior to the previous layer. In the interface of the applanation contact lens cone, a 6-mm diameter aluminum circle was placed at the center to block the laser, and ablation was limited to the midperiphery of the cornea. The laser settings were spot/line separation, 10 microm; diameter, 8.5 mm; energy for ablating the stroma, 1.3 microJ. Topography examination was used to document changes in corneal power. Light microscopy, transmission electron microscopy (TEM), and confocal microscopy in vivo were applied to observe changes in the cornea. There was significant change in mean corneal power between baseline and postoperative month 3 (n = 8; P = 0.0001), with a decrease from 46.82 D to 44.42 D. There was no haze formation or refractive regression throughout the follow-up. There were no corneal structural abnormalities under light microscopy. Activated keratocytes and necrotic debris were visible under confocal microscopy. Fibroblasts were observed, and no myofibroblasts appeared under TEM. Multilayer intrastromal ablation by the femtosecond laser with intact epithelium in the midperiphery of the corneal stroma can flatten the cornea without causing haze formation or refractive regression. This procedure allows the cornea to heal differently than when traditional corneal refractive surgery is performed and the epithelium is damaged.

  13. Actual laser removal of black soiling crust from siliceous sandstone by high pulse repetition rate equipment: effects on surface morphology

    Directory of Open Access Journals (Sweden)

    Iglesias-Campos, M. A.

    2016-03-01

    Full Text Available This research project studies the role of pulse repetition rate in laser removal of black soiling crust from siliceous sandstone, and specifically, how laser fluence correlates with high pulse repetition rates in cleaning practice. The aim is to define practical cleaning processes and determine simple techniques for evaluation based on end-users’ perspective (restorers. Spot and surface tests were made using a Q-switched Nd:YAG laser system with a wide range of pulse repetition rates (5–200 Hz, systematically analysed and compared by macrophotography, portable microscope, stereomicroscope with 3D visualizing and area roughness measurements, SEM imaging and spectrophotometry. The results allow the conclusion that for operation under high pulse repetition rates the average of total energy applied per spot on a treated surface should be attendant upon fluence values in order to provide a systematic and accurate description of an actual laser cleaning intervention.En este trabajo se estudia el papel de la frecuencia de repetición en la limpieza láser de costras de contaminación sobre una arenisca silícea, y concretamente, como se relaciona fluencia y frecuencias elevadas en una limpieza real. Se pretende definir un procedimiento práctico de limpieza y determinar técnicas sencillas de evaluación desde el punto de vista de los usuarios finales (restauradores. Para el estudio se realizaron diferentes ensayos en spot y en superficie mediante un equipo Q-switched Nd:YAG con un amplio rango de frecuencias (5–200 Hz, que se analizaron y compararon sistemáticamente mediante macrofotografía, microscopio portátil, estereomicroscopio con visualización 3D y mediciones de rugosidad en área, imágenes SEM y espectrofotometría. Los resultados permiten proponer que, al trabajar con altas frecuencias, la media de la energía total depositada por spot en la superficie debería acompañar los valores de fluencia para describir y comprender mejor una

  14. Avaliação pós-transplante de ovários íntegros e fatiados sem anastomose vascular Endocrinological, morphological and gestational assessment of intact and sliced ovarian orthotopic reimplantation or transplantation without vascular pedicle

    Directory of Open Access Journals (Sweden)

    Andy Petroianu

    2006-12-01

    Full Text Available OBJETIVO: Avaliar a fertilização, bem como aspectos endócrinos e histológicos do ovário após seu reimplante ou transplante ortotópico, sem anastomose vascular. MÉTODOS: Foram utilizadas 56 coelhas da raça Nova Zelândia Branca e Califórnia distribuídas em: Grupo 1 (n=8 - controle, apenas laparotomia e laparorrafia; Grupo 2A (n=8 - reimplante ortotópico de ovários íntegros; Grupo 2B (n=8 - reimplante ortotópico de ovários fatiados; Grupo 2C (n=8 - reimplantes ovarianos de um lado, íntegros, e, do outro lado, fatiados; Grupo Grupo 3A (n=8 - transplante ortotópico de ovários íntegros; Grupo 3B (n=8 - transplante ortotópico de ovários fatiados; Grupo 3C (n=8 - transplantes ovarianos de um lado, íntegros, e, do outro lado, fatiados. A partir do terceiro mês pós-operatório, cada coelha foi colocada para cópula. Dosou-se o estradiol, a progesterona, o FSH e o LH no nono mês pós-operatório. Estudou as morfologias macro e microscópicas dos ovários, tubas e útero, de todas os animais. Os números de gestações e de filhotes foram avaliados por meio do teste Qui-quadrado e as dosagens hormonais foram comparadas pelo one-way Anova, seguido pelo teste de Tukey-Kramer. RESULTADOS: No Grupo 1, sete (87,5% coelhas engravidaram entre o segundo e terceiro meses após início da cópula. No Grupo 2, as gestações ocorreram entre o quinto e o oitavo meses pós-operatórios e, no Grupo 3, entre o quarto e o oitavo meses pós-operatórios. A porcentagem de gravidez observada foi de 37,5% no Grupo 2A, 50% no Grupo 2B e 2C, 37,5% no Grupo 3A, 50% no Grupo 3B e 62,5% no Grupo 3C. Os níveis hormonais e o estudo morfofuncional dos ovários, tubas e úteros não apresentaram alterações. CONCLUSÃO: O reimplante ou transplante ovariano homógeno ortotópico sem pedículo vascular é eficaz para a manutenção de níveis normais de hormônios ovarianos e permitiu a fertilização natural.OBJETIVE: To assess the natural pregnancy and to

  15. Evaluation of the composition and morphology of a WTi/Si system processed by a picosecond laser

    Science.gov (United States)

    Petrović, Suzana; Peruško, D.; Radović-Bogdanović, I.; Branković, G.; Čekada, M.; Gaković, B.; Jakšić, M.; Trtica, M.; Milosavljević, M.

    2012-06-01

    In this work we studied the influence of laser radiation on the composition, structure and morphology of WTi thin films deposited on n-type (100) silicon wafers. The films were deposited by d.c. sputtering from a 70:30 at% W-Ti target, using Ar ions, to a thickness of ˜190 nm. Irradiation was performed with a pulsed Nd:YAG laser operating at 1064 nm, whereas the pulse duration was 150 ps. Laser fluences of 3.2 and 5.9 J/cm2 were found to be sufficient for modification of the WTi/silicon target system. The results show: (i) ablation of WTi thin film and a Si substrate in the central zone of spots, (ii) appearance of hydrodynamic features like resolidified material, (iii) partial ablation of the WTi thin film at the periphery and (iv) appearance of thin film cracks at the far periphery. On the non-ablated areas, the laser modification induced changes in composition, such as inter-mixing of components at the WTi/Si interface with formation of silicides in both metals. Surface oxidation was the dominant process in the ablated areas, which is demonstrated by the presence of a SiO2 phase.

  16. Effects of laser heat treatment on the fracture morphologies of X80 pipeline steel welded joints by stress corrosion

    Institute of Scientific and Technical Information of China (English)

    De-jun Kong; Cun-dong Ye

    2014-01-01

    The surfaces of X80 pipeline steel welded joints were processed with a CO2 laser, and the effects of laser heat treatment (LHT) on H2S stress corrosion in the National Association of Corrosion Engineers (NACE) solution were analyzed by a slow strain rate test. The frac-ture morphologies and chemical components of corrosive products before and after LHT were analyzed by scanning electron microscopy and energy-dispersive spectroscopy, respectively, and the mechanism of LHT on stress corrosion cracking was discussed. Results showed that the fracture for welded joints was brittle in its original state, while it was transformed to a ductile fracture after LHT. The tendencies of hydro-gen-induced corrosion were reduced, and the stress corrosion sensitivity index decreased from 35.2%to 25.3%, indicating that the stress corrosion resistance of X80 pipeline steel welded joints has been improved by LHT.

  17. Structure and morphologies of ZnO nanoparticles synthesized by pulsed laser ablation in liquid: Effects of temperature and energy fluence

    Energy Technology Data Exchange (ETDEWEB)

    Guillén, G. García; Palma, M.I. Mendivil [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455 (Mexico); Krishnan, B. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455 (Mexico); Universidad Autónoma de Nuevo León – Centro de Innovación, Investigación y Desarrollo de Ingeniería y Tecnología, Apodaca, Nuevo León 66600 (Mexico); Avellaneda, D.; Castillo, G.A.; Roy, T.K. Das [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455 (Mexico); and others

    2015-07-15

    Zinc oxide nanoparticles were prepared by pulsed laser ablation of a zinc metal target at different water temperatures (room temperature, 50, 70 and 90 °C). Ablation was carried out using 532 nm output from a pulsed (10 ns, 10 Hz) Nd:YAG laser at three different laser fluence. Analysis of the morphology, crystalline phase, elemental composition, optical and luminescent properties were done using Transmission Electron Microscopy (TEM), X-Ray Photoelectron Spectroscopy (XPS), UV–visible absorption spectroscopy and photoluminescence spectroscopy. TEM analysis showed that a change in temperature resulted in ZnO and Zn(OH){sub 2} nanoparticles with different sizes and morphologies. XPS results confirmed the compositions and chemical states of these nanoparticles. These zinc nanomaterials showed emission in the ultraviolet (UV) and blue regions. The results of this work demonstrated that by varying the liquid medium temperature, the structure, composition, morphology and optical properties of the nanomaterials could be modified during pulsed laser ablation in liquid. - Graphical abstract: Display Omitted - Highlights: • Zinc nanomaterial colloids were synthesized by PLAL. • Effects of laser fluence and the distilled water temperature were analyzed. • The final structure varied with the distilled water temperature and laser fluence. • The morphology was dependent on the distilled water temperature and laser fluence. • Zinc nanocolloids showed emission in the UV and blue region.

  18. Deposition of matrix-free fullerene films with improved morphology by matrix-assisted pulsed laser evaporation (MAPLE)

    DEFF Research Database (Denmark)

    Canulescu, Stela; Schou, Jørgen; Fæster, Søren;

    2013-01-01

    Thin films of C60 were deposited by matrix-assisted pulsed laser evaporation (MAPLE) from a frozen target of anisole with 0.67 wt% C60. Above a fluence of 1.5 J/cm2 the C60 films are strongly non-uniform and are resulting from transfer of matrix-droplets containing fullerenes. At low fluence...... the fullerene molecules in the films are intact, the surface morphology is substantially improved and there are no measurable traces of the matrix molecules in the film. This may indicate a regime of dominant evaporation at low fluence which merges into the MAPLE regime of liquid ejection of the host matrix...

  19. Effect of Apple, Baobab, Red-Chicory, and Pear Extracts on Cellular Energy Expenditure and Morphology of Caco-2 Cells using Transepithelial Electrical Resistance (TEER) and Scanning Electron Microscopy (SEM)

    Science.gov (United States)

    The present study investigated the effects of four food extracts on the Caco-2 intestinal cell line using a new transepithelial electrical resistance method (TEER) concurrent with electron microscopy (SEM). Caco-2 cells are widely used in transepithelial studies because they can be cultured to creat...

  20. In vitro evaluation of the morphologic changes on the root dentine irradiated by CO{sub 2} laser associated or not to calcium hydroxide application; Avaliacao in vitro das alteracoes morfologicas da superficie da dentina radicular irradiada pelo laser de CO{sub 2} associado ou nao a aplicacao de hidroxido de calcio

    Energy Technology Data Exchange (ETDEWEB)

    Romano, Ana Cristina Cury Camargo

    2003-07-01

    This in vitro study has evaluated the structural changes on the root dentine irradiated by a CO{sub 2} laser associated or not to calcium hydroxide application, from the irradiated surface analysis by means of Scanning Electronic Microscopy (SEM). The purpose of this evaluation has been the study of an alternative method for the treatment of dentine hypersensitivity. Fourteen human teeth were utilized, third molars, divided into 7 groups. Group I (control group) to which no treatment was applied; Groups II, III and IV were given an application of Ca (OH){sub 2} paste followed by C0{sub 2} laser irradiation, lasting 5 seconds each with intervals of 10 seconds between each application, with continuous emission, power of 0.5 W (Group II), 1.0 W (Group III), and 1.5 W (Group IV); Groups V, VI, and VII were given laser irradiations without the Ca (OH){sub 2} paste following the same parameters applied to groups II, III, and IV respectively. Morphologic changes suggesting to fusion and re-solidification have been observed, as well as the presence of material obstructing the whole analyzed surface on groups II, III, and IV (laser + Ca (OH){sub 2}). As for groups V, VI, and VII, it has been observed fusion, re-solidification, and cracks, and these results being statistically significant when compared the '(Ca (OH){sub 2})' groups to the laser groups. No statistically significant differences were observed regarding the different powers applied in the groups that used the same treatment. Despite this result, it can be stated that powers above 1.0 W (DP = 125,38 W/cm{sup 2}) are unfavorable due to the undesirable morphologic alterations and aesthetic compromising. (author)

  1. Functional properties of laser effects on morphology of liver, gall bladder and bile ducts in cholelithiasis

    National Research Council Canada - National Science Library

    Bakhtior Shamirzaev

    2012-01-01

    In 85 patients with calculous cholecystitis the preoperative preparation before laparoscopic cholecystectomy included irradiation of the area of gall bladder and epigastric puncture with low power magneto-infrared laser...

  2. Femtosecond laser additive manufacturing of YSZ

    Science.gov (United States)

    Liu, Jian; Bai, Shuang

    2017-04-01

    Laser additive manufacturing (LAM) of Yttria-Stabilized Zirconia (YSZ) is investigated using femtosecond (fs) fiber lasers. Various processing conditions are studied, which leads to desired characteristics in terms of morphology, porosity, hardness, microstructural and mechanical properties of the processed components. High-density (>99%) YSZ part with refined grain and increased hardness was obtained. Microstructure features of fabricated specimens were studied with SEM, EDX, the measured micro hardness is achieved as high as 18.84 GPa.

  3. Femtosecond laser additive manufacturing of YSZ

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jian; Bai, Shuang [PolarOnyx, Inc., San Jose, CA (United States)

    2017-04-15

    Laser additive manufacturing (LAM) of Yttria-Stabilized Zirconia (YSZ) is investigated using femtosecond (fs) fiber lasers. Various processing conditions are studied, which leads to desired characteristics in terms of morphology, porosity, hardness, microstructural and mechanical properties of the processed components. High-density (>99%) YSZ part with refined grain and increased hardness was obtained. Microstructure features of fabricated specimens were studied with SEM, EDX, the measured micro hardness is achieved as high as 18.84 GPa. (orig.)

  4. Influence of deposition temperature on the structural and morphological properties of Be{sub 3}N{sub 2} thin films grown by reactive laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Chale-Lara, F., E-mail: fabio_chale@yahoo.com.mx [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2681, Ensenada, Baja California, C.P. 22860 (Mexico); Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autonoma de Mexico, Apartado Postal 14, Ensenada CP 22860, Baja California (Mexico); Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Unidad Altamira, Km. 14.5 Carretera Tampico-Puerto Industrial, Altamira, Tamaulipas (Mexico); Farias, M.H.; De la Cruz, W. [Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autonoma de Mexico, Apartado Postal 14, Ensenada CP 22860, Baja California (Mexico); Zapata-Torres, M. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Legaria 694, Col. Irrigacion, Del. Miguel Hidalgo, Mexico D.F. (Mexico)

    2010-10-01

    Be{sub 3}N{sub 2} thin films have been grown on Si(1 1 1) substrates using the pulsed laser deposition method at different substrate temperatures: room temperature (RT), 200 deg. C, 400 deg. C, 600 deg. C and 700 deg. C. Additionally, two samples were deposited at RT and were annealed after deposition in situ at 600 deg. C and 700 deg. C. In order to obtain the stoichiometry of the samples, they have been characterized in situ by X-ray photoelectron (XPS) and reflection electron energy loss spectroscopy (REELS). The influence of the substrate temperature on the morphological and structural properties of the films was investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that all prepared films presented the Be{sub 3}N{sub 2} stoichiometry. Formation of whiskers with diameters of 100-200 nm appears at the surface of the films prepared with a substrate temperature of 600 deg. C or 700 deg. C. However, the samples grown at RT and annealed at 600 deg. C or 700 deg. C do not show whiskers on the surface. The average root mean square (RMS) roughness and the average grain size of the samples grown with respect the substrate temperature is presented. The films grown with a substrate temperature between the room temperature to 400 deg. C, and the sample annealed in situ at 600 deg. C were amorphous; while the {alpha}Be{sub 3}N{sub 2} phase was presented on the samples with a substrate temperature of 600 deg. C, 700 deg. C and that deposited with the substrate at RT and annealed in situ at 700 deg. C.

  5. Morphological characteristics of the optic nerve evaluated by confocal laser tomography (HRT3) and laser polarimetry (GDx-VCC) in a normal population from the city of Barcelona.

    Science.gov (United States)

    Fallon, M; Pazos, M; Morilla, A; Sebastián, M A; Xancó, R; Mora, C; Calderón, B; Vega, Z; Antón, A

    2015-11-01

    To evaluate morphological parameters of optic disc and retinal nerve fiber layer (RNFL) examined with confocal laser tomography (HRT3) and laser polarimetry (GDx-VCC) in a normal population, and analyze correlations of these parameters with demographic variables. Cross-sectional study in the context of a glaucoma screening campaign in the primary care center of Barcelona. The individuals selected were non-hypertensive Mediterranean Caucasians with risk for glaucoma development (individuals≥60 years old or≥40 years old with family history of glaucoma or intraocular pressure or myopia>3diopter). All subjects underwent a complete ophthalmic examination, confocal laser tomography (HRT3) and scanning laser polarimetry (GDX-VCC), subjects with results within normal limits only being included. Structural parameters were analyzed along with age, refraction, and pachymetry based on the Spearman rank correlation test. A total of 224 subjects included, with a mean age of 63.4±11.1 years. Disc areas, excavation and ring area were 2.14±0.52mm(2), 0.44±0.34mm (2) and 1.69±0.38mm(2), respectively. The mean RNFL (GDX) was 55.9±6.9μm. Age was correlated with lower ring volume, highest rate of cup shape measure, largest mean and maximum cup depth, lower nerve fiber index (NFI) and RNFL (all p-values below .05). The mean values and distribution of several parameters of the papilla and the RNFL in normal Mediterranean Caucasians population are presented. A loss of thickness of the RNFL, ring thinning, and enlarged cup was observed with increased age. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  6. Improvement of the optical and morphological properties of microlens arrays fabricated by laser using a sol–gel coating

    Energy Technology Data Exchange (ETDEWEB)

    Nieto, Daniel, E-mail: daniel.nieto@usc.es [Microoptics and GRIN Optics Group, Applied Physics Department, Faculty of Physics, University of Santiago de Compostela, Santiago de Compostela E15782 (Spain); Gómez-Varela, Ana Isabel [Microoptics and GRIN Optics Group, Applied Physics Department, Faculty of Physics, University of Santiago de Compostela, Santiago de Compostela E15782 (Spain); Martín, Yolanda Castro [Instituto de Cerámica y Vidrio (CSIC), Kelsen 5, Campus de Cantoblanco, 28049 Madrid (Spain); O’Connor, Gerard M. [School of Physics, National Centre for Laser Applications, National University of Ireland, University Road, Galway (Ireland); Flores-Arias, María Teresa, E-mail: maite.flores@usc.es [Microoptics and GRIN Optics Group, Applied Physics Department, Faculty of Physics, University of Santiago de Compostela, Santiago de Compostela E15782 (Spain)

    2015-10-01

    Highlights: • Microlens arrays were fabricated on soda-lime glass using a Ti:Sapphire laser. • A SiO{sub 2} coating prepared via sol–gel route was used to improve the microlens quality. • The sol–gel coating was deposited at the microlens top surface using a dip coating. • Optical properties of the microlenses were improved by the coating. - Abstract: We present a simple, repeatable and non-contaminant method to improve the optical and morphological properties of microlens arrays. It consists on depositing hybrid SiO{sub 2} (TEOS, MTES) coatings via sol–gel route onto microlens arrays fabricated using a Ti:Sapphire Femtosecond Amplitude Systems S-pulse HP laser operating at 1030 nm. The deposited silica sol–gel layer reduces the surface roughness (quantified as the root mean square) and increases the quality of the interstices between the microlenses generated by the ablation process, thus improving the contrast and homogeneity of the foci of the microlens array. The proposed technique allows us to obtain microlenses with a diameter in the range of 15–20 μm and a depth of 1.5–15 μm. For the characterization of the micro-optical structures, the UV–visible spectroscopy, spectral ellipsometry, confocal microscopy and beam profilometry were used. The proof-of-principle presented in this paper can be used to improve the optical and morphological properties of micro-optical systems of different nature by tailoring the parameters involved in both the laser ablation and sol–gel processes comprising the starting materials, solvent and catalysts nature and concentration, hydrolysis ratio, aging time and/or deposition conditions.

  7. Nanosecond pulsed laser deposition of TiO{sub 2}: nanostructure and morphology of deposits and plasma diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, Mikel; Walczak, Malgorzata; Oujja, Mohamed; Cuesta, Angel [Instituto de Quimica Fisica Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Castillejo, Marta, E-mail: marta.castillejo@iqfr.csic.e [Instituto de Quimica Fisica Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain)

    2009-10-30

    Nanostructured TiO{sub 2} films on Si (100) substrates have been grown by nanosecond pulsed laser deposition at the wavelengths of 266, 355 and 532 nm using a Q-switched Nd:YAG laser and TiO{sub 2} sintered rutile targets. The effect of laser irradiation wavelength, the temperature of the substrate and the presence of O{sub 2} as background gas on the crystallinity and surface structure of deposits were determined, together with the composition, expansion dynamics and thermodynamic parameters of the ablation plume. Deposits were analyzed by X-ray photoelectron spectroscopy, X-ray diffraction, environmental scanning electron microscopy and atomic force microscopy, while in situ monitoring of the plume was carried out and characterized with spectral, temporal and spatial resolution by optical emission spectroscopy. Stoichiometric, crystalline deposits, with nanostructured morphology were obtained at substrate temperatures above 600 {sup o}C. Microscopic particulates were found overimposed on the nanostructured films but their size and density were significantly reduced by operating at short wavelength (266 nm) and upon addition of a low pressure of oxygen (0.05 Pa). The dominant crystalline phase is rutile at 355 and 532 nm. At the short irradiation wavelength, 266 nm, the preferred phase in the presence of oxygen is rutile, while anatase is preferably observed under vacuum. The narrowest size distribution and smallest nanoparticle diameters, of around 25 nm, were found by deposition at 266 nm under 0.05 Pa of oxygen.

  8. Microstructure and Fractural Morphology of Cobalt-based Alloy Laser Cladding

    Institute of Scientific and Technical Information of China (English)

    CHEN Hao; PAN Chun-xu

    2003-01-01

    The solidification features,micro-segregation,and fracture characteristics of cobalt-based alloy on the substrate of 20CrMo steel by laser cladding were studied by using electron microscopy.Experimental results show that the fine columnar grains and cellular dendrite grains are obtained which are perpendicular to the coating/substrate interface;the primary arms are straight while the side branches are degenerated;the microstructure consists of primary face-centered cubic (fcc) Co dendrites and a network of Cr-enriched eutectic M23C6 (M=Cr,W,Fe) carbides;the micro-segregation is severe for the rapid heating and cooling of laser cladding;the typical brittle intergranular fracture occurs in cobalt-based laser cladding layer.

  9. Análise química e morfológica do esmalte dentário humano tratado com laser argônio durante a colagem ortodôntica Chemical and morphological analysis of the human dental enamel treated with argon laser during orthodontic bonding

    Directory of Open Access Journals (Sweden)

    Glaucio Serra Guimarães

    2011-04-01

    Full Text Available INTRODUÇÃO: as principais utilizações do laser argônio na Ortodontia são a redução do tempo de polimerização durante a colagem ortodôntica e o aumento da resistência à cárie do esmalte dentário. OBJETIVO: o objetivo deste trabalho foi avaliar as alterações químicas e morfológicas do esmalte dentário humano tratado com laser argônio nos parâmetros da colagem ortodôntica. MÉTODOS: quinze primeiros pré-molares hígidos, extraídos por indicação ortodôntica, foram selecionados e seccionados no sentido do longo eixo em dois segmentos iguais. Uma metade de cada elemento dentário foi tratada e a outra permaneceu sem tratamento. Um total de 30 amostras foi analisado, criando o grupo laser (n = 15 e o grupo controle (n = 15. O tratamento foi feito com laser argônio com 250mW de potência por 5 segundos, com densidade de energia de 8J/cm². RESULTADOS: a análise de difração de raios X demonstrou duas fases em ambos os grupos, as fases apatita e monetita. A redução da fase monetita foi significativa após o tratamento com laser, sugerindo maior cristalinidade. A análise de Espectroscopia de Energia Dispersiva (EDS indicou aumento na razão cálcio-fósforo no grupo laser, compatível com a diminuição da fase monetita. A morfologia superficial do esmalte dentário apresentou-se mais lisa após o tratamento com laser argônio. CONCLUSÕES: o aumento de cristalinidade e a lisura superficial do esmalte no grupo laser são fatores sugestivos de aumento de resistência à cárie no esmalte dentário.INTRODUCTION: The main utilities of the argon laser in orthodontics are the high speed curing process in orthodontic bonding and the caries resistance promotion of the tooth enamel. OBJECTIVE: The objective of this study was to evaluate the chemical and morphological changes in the tooth enamel treated with the argon laser in the orthodontic bonding parameters. METHODS: Fifteen sound human first premolars, removed for orthodontic

  10. Avaliação morfológica da união entre adesivo/resina composta e dentina irradiada com laser Er:YAG e laser Nd:YAG: estudo comparativo por microscopia de varredura Morphological evaluation of the bonding between adhesive/composite resin and dentin irradiated with Er:YAG and Nd:YAG lasers: comparative study using scanning microscopy

    Directory of Open Access Journals (Sweden)

    Margareth ODA

    2001-12-01

    the best known method. However, alternative methods for treating the dentin surface have been discussed in the literature, including the utilization of some kinds of laser irradiation. The purpose of this research was to morphologically evaluate the bond between adhesive materials and the dentin treated with Er:YAG and Nd:YAG lasers, in a comparative study by means of scanning electron microscopy (SEM. Irradiation either substituted acid etching, or was associated to it. Recently extracted bovine incisors were utilized. They received class V cavity preparations and were restored with a bonding system and a light-cured composite resin. Meanwhile, some of the teeth underwent irradiation with Er:YAG laser or Nd:YAG laser before the application of the bonding agent and the composite resin. The samples were selected, prepared for SEM and submitted to morphological analysis. Data were registered in photomicrographs. Based on the microscopic observations, we concluded that only in the dentin surfaces submitted to irradiation with Er:YAG laser and to acid conditioning there was penetration of resin into the dentine. With the Nd:YAG laser treatment, there was only visual superposition of resin over the dentin surface, which suggests that there was only occlusion of the tubules, with characteristics of fusion in the superficial dentine.

  11. Estudo morfológico de superfícies ósseas após secção por pontas diamantadas ou laser de érbio: YAG Morphological evaluation of bone surfaces after sectioning with diamond points or erbium: YAG laser

    Directory of Open Access Journals (Sweden)

    Massuji KURAMOTO Jr.

    2000-06-01

    Full Text Available O objetivo deste trabalho foi analisar morfologicamente as superfícies ósseas resultantes da secção por pontas diamantadas ou por laser de érbio:YAG. Cinco ratos (Rattus norvegicus albinus foram sacrificados por dose letal de fenobarbital. Após a execução deste procedimento, os ossos predeterminados foram submetidos à secção por pontas diamantadas ou por laser de érbio:YAG em uma energia de 300 mJ por pulso e taxa de repetição de 2 Hz. As amostras foram submetidas a análise em microscópio eletrônico de varredura, revelando a existência de um padrão para as secções obtidas com cada instrumento, sendo verificada uma superfície mais regular nas amostras seccionadas com o laser de érbio:YAG. Em aumentos da ordem de 3000 vezes, pode-se observar indícios de fusão e seqüente solidificação das superfícies seccionadas por meio do laser de érbio:YAG. Conclui-se que o laser de érbio:YAG foi eficaz na remoção de tecido ósseo, mas que, nos parâmetros utilizados neste estudo, foi responsável por alterações morfológicas sugestivas de significativo aumento de temperatura, não devendo ser indicado, nestas condições, para a execução de secções ósseas.The purpose of this study was to analyze bone surfaces cut by Er:YAG laser or by diamond points. Five male rats (Rattus norvegicus albinus were killed by lethal dose of phenobarbital, and selected bones were cut by Er:YAG laser at 300 mJ and 2 Hz, or by diamond points. The samples were submitted to evaluation through SEM at standard magnifications. By analyzing the surfaces, the authors could observe a pattern for each group, with a smoother surface in the laser cut group than in the diamond cut group. In higher magnifications, the images suggest melting and solidifying in the laser group. The authors conclude that the laser was effective in bone cutting. However, it was responsible for morphological changes that suggest a significant temperature increase.

  12. Natural and Anthropogenic Controls on Beach Morphology from Analysis of Terrestrial Scanning Laser Time Series Data, Waimea Bay, Oahu.

    Science.gov (United States)

    Brooks, B. A.; Becker, J.; Merrifield, M.; Foster, J.; Ericksen, T.; Hilmer, T.; Vitousek, S.

    2008-12-01

    To determine the environmental conditions and timing leading to long time scale (O(years)) and specific event (O(days-hours)) changes in beach morphology we collected terrestrial scanning laser (TLS) topographic time series, offshore wave data, and high resolution digital photographs of the entire beach at Waimea Bay, Oahu from January through June 2007. Each survey had better than 1cm range-resolution, average spot-spacing of 10 cm, and had tilts removed using GPS-based geocoding. The TLS surveys on monthly time-scales quantify the seasonal transition in beach morphology and volume forced by high waves (winter) to small waves (summer). The surveys over daily to hourly time scales quantify the evolution of discrete morphological features. For instance, two surveys taken three hours apart on 27 April 2007 when significant wave height was roughly 0.7m document an order 0.1 m increase in sand elevation occurring along the foreshore indicating active sand accretion following an erosion event on 24 April 2007 when significant wave height was roughly 2.5m. Well-defined fore-beach and back-beach cuspate features were present during the surveys. The elevation difference map shows that the main area of accretion occurred in the fore-beach cusp embayments, i.e., the beach cusps appear to be filling in with sand. We further use the TLS time series data to quantify the subaerial morphologic signal and volumetric beach change budget of foot-traffic on the beach. Our initial observations indicate that the upper portions of the beach, rarely affected by waves but receiving hundreds to thousands of visitors per day, exhibits convex upward character typical of diffusive forcing. We assess whether a diffusive landscape evolution model based on linear or non-linear flux laws describes the temporal and spatial evolution of the upper parts of beaches where wave forcing rarely occurs.

  13. Morphological changes induced in testicles by high-intensity laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Linkova, G.N.

    Syrian hamsters were employed in a trial of the effectiveness of a Nd laser in inducing sterility. The testes were irradiated with a GOS-1001 laser emitting at 1.06 ..mu..m with an output energy of 1000 J/cm/sup 2/ for ca. 5 msec with a 0.5 cm beam. The gross and histologic examination over a period of 12 to 60 days revealed progressive atrophy of all the testicular elements and destruction of the components of the blood-testes barrier. In the case with thermal and mechanical trauma, there was no histologic evidence of neoplastic transformations. The basic mechanism underlying the pathologic changes was an autoimmune process accompanied by an increasing degree of granulation. 7 references, 3 figures.

  14. Raman and SEM analysis of a biocolonised hot spring travertine terrace in Svalbard, Norway

    Directory of Open Access Journals (Sweden)

    Jorge-Villar Susana E

    2007-08-01

    Full Text Available Abstract Background A profile across 8 layers from a fossil travertine terrace from a low temperature geothermal spring located in Svalbard, Norway has been studied using both Raman spectroscopy and SEM (Scanning Electron Microscopy techniques to identify minerals and organic life signals. Results Calcite, anatase, quartz, haematite, magnetite and graphite as well as scytonemin, three different carotenoids, chlorophyll and a chlorophyll-like compound were identified as geo- and biosignatures respectively, using 785 and/or 514 nm Raman laser excitation wavelengths. No morphological biosignatures representing remnant microbial signals were detected by high-resolution imaging, although spectral analyses indicated the presence of organics. In contrast, in all layers, Raman spectra identified a series of different organic pigments indicating little to no degradation or change of the organic signatures and thus indicating the preservation of fossil biomarker compounds throughout the life time of the springs despite the lack of remnant morphological indicators. Conclusion With a view towards planetary exploration we discuss the implications of the differences in Raman band intensities observed when spectra were collected with the different laser excitations. We show that these differences, as well as the different detection capability of the 785 and 514 nm laser, could lead to ambiguous compound identification. We show that the identification of bio and geosignatures, as well as fossil organic pigments, using Raman spectroscopy is possible. These results are relevant since both lasers have been considered for miniaturized Raman spectrometers for planetary exploration.

  15. Studies on the Surface Morphology and Orientation of CeO2 Films Deposited by Pulsed Laser Ablation

    Science.gov (United States)

    Develos, Katherine; Kusunoki, Masanobu; Ohshima, Shigetoshi

    1998-11-01

    We studied the surface morphology and orientation of CeO2 films grown by pulsed laser ablation (PLA) on r-cut (1\\=102) Al2O3 substrates and evaluated the effects of predeposition annealing conditions of Al2O3 and film thickness of CeO2. The annealing of Al2O3 substrates improves the smoothness of the surface and performing this in high vacuum leads to better crystallinity and orientation of deposited CeO2 films compared to those annealed in oxygen. A critical value of the film thickness was found beyond which the surface roughness increases abruptly. Atomic force microscopy (AFM) study showed that the surface of CeO2 films is characterized by a mazelike pattern. Increasing the film thickness leads to the formation of larger islands which cause the increase in the surface roughness of the films. The areal density and height of these islands increased with film thickness.

  16. High resolution 3D laser scanner measurements of a strike-slip fault quantify its morphological anisotropy at all scales

    CERN Document Server

    Renard, Francois; Marsan, Davd; Schmittbuhl, Jean

    2008-01-01

    The surface roughness of a recently exhumed strikeslip fault plane has been measured by three independent 3D portable laser scanners. Digital elevation models of several fault surface areas, from 1 m2 to 600 m2, have been measured at a resolution ranging from 5 mm to 80 mm. Out of plane height fluctuations are described by non-Gaussian distribution with exponential long range tails. Statistical scaling analyses show that the striated fault surface exhibits self-affine scaling invariance with a small but significant directional morphological anisotropy that can be described by two scaling roughness exponents, H1 = 0.7 in the direction of slip and H2 = 0.8 perpendicular to the direction of slip.

  17. Effects of oxidizing medium on the composition, morphology and optical properties of copper oxide nanoparticles produced by pulsed laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Gondal, M.A., E-mail: magondal@kfupm.edu.sa [Laser Research Laboratory, Physics Department and Center of Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Qahtan, Talal F.; Dastageer, M.A. [Laser Research Laboratory, Physics Department and Center of Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Saleh, Tawfik A. [Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Maganda, Yasin W. [Laser Research Laboratory, Physics Department and Center of Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Anjum, D.H. [Nanofabrication, Imaging and Characterization Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23599-6900 (Saudi Arabia)

    2013-12-01

    Pulsed laser ablation in liquid (PLAL) with 532 nm wavelength laser with 5 ns pulse duration is used to produce the nanostructure copper oxide and the effects of oxidizing media (deionized water and hydrogen peroxide) on the composition, morphology and optical properties of the product materials produced by PLAL were studied. XRD and TEM studies indicate that in the absence of hydrogen peroxide, the product material is in two phases (Cu/Cu{sub 2}O) with the spherical nanoparticle structure, whereas in the presence of hydrogen peroxide in the liquid medium, the product material revealed other two phases (Cu/CuO) with nanorod-like structure. The optical studies revealed a considerable red shift (3.34–2.5 eV) in the band gap energy in the case of hydrogen peroxide in the liquid medium in PLAL synthesis compared to the one in the absence of it. Also the product material in the presence of hydrogen peroxide in the liquid medium showed a reduced photoluminescence intensity indicating the reduced electron–hole recombination rate. The red shift in the band gap energy and the reduced electron–hole recombination rate make the product material an ideal photocatalyst to harvest solar radiation for various applications. The most relevant signals on the FTIR spectrum for the samples are the absorption bands in the region between 450 and 700 cm{sup −1} which are the characteristics bands of copper-oxygen bonds. The reported laser ablation approach for the synthesis of Cu{sub 2}O and CuO nanoparticles has the advantages of being clean method with controlled particle properties.

  18. Effects of oxidizing medium on the composition, morphology and optical properties of copper oxide nanoparticles produced by pulsed laser ablation

    KAUST Repository

    Gondal, M. A.

    2013-12-01

    Pulsed laser ablation in liquid (PLAL) with 532 nm wavelength laser with 5 ns pulse duration is used to produce the nanostructure copper oxide and the effects of oxidizing media (deionized water and hydrogen peroxide) on the composition, morphology and optical properties of the product materials produced by PLAL were studied. XRD and TEM studies indicate that in the absence of hydrogen peroxide, the product material is in two phases (Cu/Cu2O) with the spherical nanoparticle structure, whereas in the presence of hydrogen peroxide in the liquid medium, the product material revealed other two phases (Cu/CuO) with nanorod-like structure. The optical studies revealed a considerable red shift (3.34-2.5 eV) in the band gap energy in the case of hydrogen peroxide in the liquid medium in PLAL synthesis compared to the one in the absence of it. Also the product material in the presence of hydrogen peroxide in the liquid medium showed a reduced photoluminescence intensity indicating the reduced electron-hole recombination rate. The red shift in the band gap energy and the reduced electron-hole recombination rate make the product material an ideal photocatalyst to harvest solar radiation for various applications. The most relevant signals on the FTIR spectrum for the samples are the absorption bands in the region between 450 and 700 cm-1 which are the characteristics bands of copperoxygen bonds. The reported laser ablation approach for the synthesis of Cu2O and CuO nanoparticles has the advantages of being clean method with controlled particle properties. © 2013 Elsevier B.V. All rights reserved.

  19. A comparative scanning electron microscopy study between hand instrument, ultrasonic scaling and erbium doped:Yttirum aluminum garnet laser on root surface: A morphological and thermal analysis

    Directory of Open Access Journals (Sweden)

    Mitul Kumar Mishra

    2013-01-01

    Full Text Available Background and Objectives: Scaling and root planing is one of the most commonly used procedures for the treatment of periodontal diseases. Removal of calculus using conventional hand instruments is incomplete and rather time consuming. In search of more efficient and less difficult instrumentation, investigators have proposed lasers as an alternative or as adjuncts to scaling and root planing. Hence, the purpose of the present study was to evaluate the effectiveness of erbium doped: Yttirum aluminum garnet (Er:YAG laser scaling and root planing alone or as an adjunct to hand and ultrasonic instrumentation. Subjects and Methods: A total of 75 freshly extracted periodontally involved single rooted teeth were collected. Teeth were randomly divided into five treatment groups having 15 teeth each: Hand scaling only, ultrasonic scaling only, Er:YAG laser scaling only, hand scaling + Er:YAG laser scaling and ultrasonic scaling + Er:YAG laser scaling. Specimens were subjected to scanning electron microscopy and photographs were evaluated by three examiners who were blinded to the study. Parameters included were remaining calculus index, loss of tooth substance index, roughness loss of tooth substance index, presence or absence of smear layer, thermal damage and any other morphological damage. Results: Er:YAG laser treated specimens showed similar effectiveness in calculus removal to the other test groups whereas tooth substance loss and tooth surface roughness was more on comparison with other groups. Ultrasonic treated specimens showed better results as compared to other groups with different parameters. However, smear layer presence was seen more with hand and ultrasonic groups. Very few laser treated specimens showed thermal damage and morphological change. Interpretation and Conclusion: In our study, ultrasonic scaling specimen have shown root surface clean and practically unaltered. On the other hand, hand instrument have produced a plane surface

  20. Chemical, morphological and chromatic behavior of mural paintings under Er:YAG laser irradiation

    Science.gov (United States)

    Striova, J.; Camaiti, M.; Castellucci, E. M.; Sansonetti, A.

    2011-08-01

    Several pigments (malachite CuCO3ṡCu(OH)2, azurite 2CuCO3ṡCu(OH)2, yellow ochre (goethite α-FeOOH, gypsum CaSO4ṡ2H2O), St. John's white CaCO3 formed from slaked lime) and respective mural paintings specimens were subjected to the free-running Er:YAG laser radiation in order to study their damage thresholds, in a broad range of laser fluences, both in dry and wet conditions. The specimens' damage thresholds were evaluated by spectroscopic methods, colorimetric measurements and microscopic observation. The pigments containing -OH groups were found to be more sensitive than St. John's white; hence the most sensitive paint layers in dry conditions are those containing malachite, azurite (both 1.3 J/cm2) and yellow ochre (2.5 J/cm2) as compared to the ones containing St. John's white (15.2 J/cm2). The presence of wetting agents (w.a.) attenuated the pigments chemical alteration. The damage thresholds of all the paint layers, in presence of w.a., were found to be around 2.5 J/cm2. The alteration was caused by thermo-mechanical damage and by binding medium ablation of a fresco and a secco prepared specimens, respectively.

  1. Quantification of morphology of bacterial colonies using laser scatter measurements and solid element optical modeling

    Science.gov (United States)

    Leavesley, Silas; Bayraktar, Bülent; Venkatapathi, Murugesan; Hirleman, E. Dan; Bhunia, Arun K.; Robinson, J. Paul; Hassler, Richard; Smith, Linda; Rajwa, Bartek

    2007-02-01

    Traditional biological and chemical methods for pathogen identification require complicated sample preparation for reliable results. Optical scattering technology has been used for identification of bacterial cells in suspension, but with only limited success. Our published reports have demonstrated that scattered light based identification of Listeria colonies growing on solid surfaces is feasible with proper pattern recognition tools. Recently we have extended this technique to classification of other bacterial genera including, Salmonella, Bacillus, and Vibrio. Our approach may be highly applicable to early detection and classification of pathogens in food-processing industry and in healthcare. The unique scattering patterns formed by colonies of different species are created through differences in colony microstructure (on the order of wavelength used), bulk optical properties, and the macroscopic morphology. While it is difficult to model the effect on scatter-signal patterns owing to the microstructural changes, the influence of bulk optical properties and overall shape of colonies can be modeled using geometrical optics. Our latest research shows that it is possible to model the scatter pattern of bacterial colonies using solid-element optical modeling software (TracePro), and theoretically assess changes in macro structure and bulk refractive indices. This study allows predicting the theoretical limits of resolution and sensitivity of our detection and classification methods. Moreover, quantification of changes in macro morphology and bulk refractive index provides an opportunity to study the response of colonies to various reagents and antibiotics.

  2. Morphology and orientation of β-BaB{sub 2}O{sub 4} crystals patterned by laser in the inside of samarium barium borate glass

    Energy Technology Data Exchange (ETDEWEB)

    Nishii, Akihito; Shinozaki, Kenji; Honma, Tsuyoshi; Komatsu, Takayuki, E-mail: komatsu@mst.nagaokaut.ac.jp

    2015-01-15

    Nonlinear optical β-BaB{sub 2}O{sub 4} crystal lines (β-BBO) were patterned in the inside of 8Sm{sub 2}O{sub 3}–42BaO–50B{sub 2}O{sub 3} glass by irradiations of continuous-wave Yb:YVO{sub 4} lasers with a wavelength of 1080 nm (power: P=0.8–1.0 W, scanning speed: S=0.2–2.5 μm/s), in which the laser focal position was moved gradually from the surface to the inside. The morphology, size, and orientation of β-BBO crystals were examined from polarization optical microscope and birefringence imaging observations. It was demonstrated that c-axis oriented β-BBO crystals with long lengths (e.g., 20 mm) were patterned in the inside of the glass. The morphology of β-BBO in the cross-section of lines was a rectangular shape with rounded corners, and the volume of β-BBO formed increased with increasing laser power and with decreasing laser scanning speed. The maximum depth in the inside from the surface for β-BBO patterning increased with increasing laser power, e.g., D{sub max}∼100 μm at P=0.8 W, D{sub max}∼170 μm at P=0.9 W, and D{sub max}∼200 μm at P=1 W. The present study proposes that the laser-induced crystallization opens a new door for applied engineering in glassy solids. - Graphical abstract: This figure shows the POM photographs for β-BaB{sub 2}O{sub 4} crystal lines patterned by cw Yb:YVO{sub 4} fiber laser irradiations with a laser power of P=0.8 W and a laser scanning speed S=2 μm/s in the glass. The laser focal point was moved gradually from the surface into the inside. The results shown in Fig. 1 demonstrate that it is possible to pattern highly oriented β-BaB{sub 2}O{sub 4} crystals even in the inside of glasses. - Highlights: • β-BaB{sub 2}O{sub 4} crystal lines were patterned in the inside of a glass by lasers. • Laser focal position was moved gradually from the surface to the inside. • Birefringence imaging was observed. • Morphology, size, and orientation of crystals were clarified. • Crystal lines with long lengths

  3. Aerogel Track Morphology: Measurement, Three Dimensional Reconstruction and Particle Location using Confocal Laser Scanning Microscopy

    Science.gov (United States)

    Kearsley, A. T.; Ball, A. D.; Wozniakiewicz, P. A.; Graham, G. A.; Burchell, M. J.; Cole, M. J.; Horz, F.; See, T. H.

    2007-01-01

    The Stardust spacecraft returned the first undoubted samples of cometary dust, with many grains embedded in the silica aerogel collector . Although many tracks contain one or more large terminal particles of a wide range of mineral compositions , there is also abundant material along the track walls. To help interpret the full particle size, structure and mass, both experimental simulation of impact by shots and numerical modeling of the impact process have been attempted. However, all approaches require accurate and precise measurement of impact track size parameters such as length, width and volume of specific portions. To make such measurements is not easy, especially if extensive aerogel fracturing and discoloration has occurred. In this paper we describe the application and limitations of laser confocal imagery for determination of aerogel track parameters, and for the location of particle remains.

  4. Study on the surface and interface morphological microstructure of Tung oil-coated fertilizers by SEM%桐油包膜肥料表面及界面微观形态结构的SEM研究

    Institute of Scientific and Technical Information of China (English)

    唐辉; 王亚明; 杨爱明; 刘剑虹

    2004-01-01

    以桐油为主要成膜材料制备了桐油包膜尿素和桐油包膜复合肥料.用扫描电子显微镜(SEM)对包膜肥料的表面、界面及养分溶解释放后的表面进行了微观形态结构研究.结果表明:桐油能很好地分散并渗入尿素和NPK复合肥料的多孔表面形成附着良好的包膜层,在包膜率小于10%时包膜层厚度介于50~150μm之间.桐油包膜层表面具有特征的波纹状形貌,养分溶解释放后在包膜肥料的包膜层表面留下了水和养分溶液进出的凹陷通道.

  5. SEM in applied marketing research

    DEFF Research Database (Denmark)

    Sørensen, Bjarne Taulo; Tudoran, Ana Alina

    In this paper we discuss two SEM approaches: an exploratory structural equation modelling based on a more liberalised and inductive philosophy versus the classical SEM based on the traditional hypothetical-deductive approach. We apply these two modelling techniques to data from a consumer survey ...

  6. Characterizing Earthflow Surface Morphology With Statistical and Spectral Analyses of Airborne Laser Altimetry

    Science.gov (United States)

    McKean, J.; Roering, J.

    High-resolution laser altimetry can depict the topography of large landslides with un- precedented accuracy and allow better management of the hazards posed by such slides. The surface of most landslides is rougher, on a local scale of a few meters, than adjacent unfailed slopes. This characteristic can be exploited to automatically detect and map landslides in landscapes represented by high resolution DTMs. We have used laser altimetry measurements of local topographic roughness to identify and map the perimeter and internal features of a large earthflow in the South Island, New Zealand. Surface roughness was first quantified by statistically characterizing the local variabil- ity of ground surface orientations using both circular and spherical statistics. These measures included the circular resultant, standard deviation and dispersion, and the three-dimensional spherical resultant and ratios of the normalized eigenvalues of the direction cosines. The circular measures evaluate the amount of change in topographic aspect from pixel-to-pixel in the gridded data matrix. The spherical statistics assess both the aspect and steepness of each pixel. The standard deviation of the third di- rection cosine was also used alone to define the variability in just the steepness of each pixel. All of the statistical measures detect and clearly map the earthflow. Cir- cular statistics also emphasize small folds transverse to the movement in the most active zone of the slide. The spherical measures are more sensitive to the larger scale roughness in a portion of the slide that includes large intact limestone blocks. Power spectra of surface roughness were also calculated from two-dimensional Fourier transformations in local test areas. A small earthflow had a broad spectral peak at wavelengths between 10 and 30 meters. Shallower soil failures and surface erosion produced surfaces with a very sharp spectral peak at 12 meters wavelength. Unfailed slopes had an order of magnitude

  7. Morphologies of High Redshift, Dust Obscured Galaxies from Keck Laser Guide Star Adaptive Optics

    CERN Document Server

    Melbourne, J; Armus, Lee; Dey, Arjun; Brand, K; Thompson, D; Soifer, B T; Matthews, K; Jannuzi, B T; Houck, J R

    2008-01-01

    Spitzer MIPS images in the Bootes field of the NOAO Deep Wide-Field Survey have revealed a class of extremely dust obscured galaxy (DOG) at z~2. The DOGs are defined by very red optical to mid-IR (observed-frame) colors, R - [24 um] > 14 mag, i.e. f_v (24 um) / f_v (R) > 1000. They are Ultra-Luminous Infrared Galaxies with L_8-1000 um > 10^12 -10^14 L_sun, but typically have very faint optical (rest-frame UV) fluxes. We imaged three DOGs with the Keck Laser Guide Star Adaptive Optics (LGSAO) system, obtaining ~0.06'' resolution in the K'-band. One system was dominated by a point source, while the other two were clearly resolved. Of the resolved sources, one can be modeled as a exponential disk system. The other is consistent with a de Vaucouleurs profile typical of elliptical galaxies. The non-parametric measures of their concentration and asymmetry, show the DOGs to be both compact and smooth. The AO images rule out double nuclei with separations of greater than 0.1'' (< 1 kpc at z=2), making it unlikely ...

  8. Laser assisted removal of synthetic painting-conservation materials using UV radiation of ns and fs pulse duration: Morphological studies on model samples

    Science.gov (United States)

    Pouli, P.; Nevin, A.; Andreotti, A.; Colombini, P.; Georgiou, S.; Fotakis, C.

    2009-02-01

    In an effort to establish the optimal parameters for the cleaning of complex layers of polymers (mainly based on acrylics, vinyls, epoxys known as Elvacite, Laropal, Paraloid B72, among others) applied during past conservation treatments on the surface of wall paintings, laser cleaning tests were performed with particular emphasis on the plausible morphological modifications induced in the remaining polymeric material. Pulse duration effects were studied using laser systems of different pulse durations ( ns and fs) at 248 nm. Prior to tests on real fragments from the Monumental Cemetery in Pisa (Italy) which were coated with different polymers, attention was focused on the study of model samples consisting of analogous polymer films cast on quartz disks. Ultraviolet irradiation is strongly absorbed by the studied materials both in ns and fs irradiation regimes. However, it is demonstrated that ultrashort laser pulses result in reduced morphological alterations in comparison to ns irradiation. In addition, the dependence of the observed alterations on the chemical composition of the consolidation materials in both regimes was examined. Most importantly, it was shown that in this specific conservation problem, an optimum cleaning process may rely not only on the minimization of laser-induced morphological changes but also on the exploitation of the conditions that favour the disruption of the adhesion between the synthetic material and the painting.

  9. 扫描电镜下山东丹参与近缘种花粉形态特征比较观察%Observation and comparison on morphological characteristics of pollen of Salvia shandongensis and its relatives by SEM

    Institute of Scientific and Technical Information of China (English)

    李晓娟; 李建秀; 孙经兴; 宋英杰; 张永清

    2013-01-01

      采用光学显微镜和扫描电镜相结合,对山东丹参、丹参、南丹参发育良好成熟的花粉粒进行比较观察。结果表明:花粉粒形态、大小和外壁网状雕纹特征均具有较显著区别,首次为山东丹参新种积累孢粉学资料、确立其在植物分类学上的地位以及研究其种质,提供花粉形态的重要依据;丹参和南丹参花粉粒形态特征及外壁网状雕纹与前人报道相一致,为揭示山东丹参与丹参、南丹参之间的亲缘关系及种间分类鉴定提供了孢粉学依据;也为山东丹参药用植物新资源的开发提供科学依据。%Well‐developed mature pollen grains of Salvia shandongensis ,S .miltiorrhiza and S .bow leyana are exam‐ined by using light microscope and scanning electron microscope .The results indicated that there were clear distinc‐tions among the shape ,size and exine sculpture of S .miltiorrhiza plants’ pollen .This study not only first provided the important pollen morphological basis for accumulating the palynology information for S .shandongensis new spe‐cies ,establishing its position in plant taxonomy and researching its species quality ;pollen grains morphological fea‐tures and exine sculpture of S .miltiorrhiza and S .bowleyana were consistent with previous reports and provided the palynology information for revealing their genetic relationships of S .shandongensis ,S .miltiorrhiza and S .bowleyana and distinguishing their species taxonomy ,but also provided scientific basis for the development of new medicinal plant resources of S .shandongensis .

  10. Morphology and Mechanism of Gaussian Distributed Laser Induced Forward Transfer Cu Film%高斯分布激光前向转印Cu薄膜形貌及机理

    Institute of Scientific and Technical Information of China (English)

    刘威; 窦广彬; 王春青; 田艳红; 叶交托

    2013-01-01

    激光诱发前向转印技术,作为一种微加工手段,具有制备微小结构的能力,目前已经成为微细加工领域的研究热点.通过改变高斯分布激光脉冲功率密度,进行了Cu薄膜在石英玻璃表面的转印实验,并对转印沉积薄膜进行了光学显微镜、扫描电子显微镜(SEM)和X射线光电子能谱(XPS)表面氧化状态分析,探讨了激光脉冲功率密度与沉积薄膜的尺寸、特殊形貌以及薄膜厚度均匀性的关系,并在此基础上研究了激光转印Cu薄膜的机理.结果表明,当激光平均脉冲功率密度达到1×105 W/cm2时,Cu薄膜的转印才可以发生.随着激光脉冲功率密度的增加,转印Cu薄膜尺寸增加,并由薄膜转变为圆环形,最终尺寸达到一定值.激光转印薄膜表层10 nm以下,基本上没有氧化发生.薄膜附着在基板上,连接紧密,并未观察到明显的扩散迹象.%As a method of micro fabrication, laser induced forward transfer (LIFT) technology can be used to make microstructures. Presently, the fabrication process has become a popular issue in the field of micro-machining. A Cu thin film is transferred from one quartz substrate to another quartz substrate by regulating the pulse power density of Gaussian distributed laser beam. The transferred Cu thin film is characterized by optical microscopy, scanning electron microscopy (SEM), and X-ray photoelectron microscopy (XPS) analysis. The relationship between pulse power density of laser beam and size, special morphology and uniformity of transferred Cu film is discussed, and the oxidation condition of the transferred Cu film is also studied. Moreover, the mechanism of the transferred process is analyzed based on the results. It is found that the Cu film transfer process can be realized when the average pulse power density of laser beam reaches 1×105 W/cm2. With the increase of pulse power density of laser beam, the size of transferred Cu film is also enlarged, and reaches a

  11. Graphitic carbon nanospheres: A Raman spectroscopic investigation of thermal conductivity and morphological evolution by pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Radhe; Sahoo, Satyaprakash, E-mail: satya504@gmail.com, E-mail: rkatiyar@hpcf.upr.edu; Chitturi, Venkateswara Rao; Katiyar, Ram S., E-mail: satya504@gmail.com, E-mail: rkatiyar@hpcf.upr.edu [Department of Physics, University of Puerto Rico, San Juan, Puerto Rico 00936-8377 (United States)

    2015-12-07

    Graphitic carbon nanospheres (GCNSs) were prepared by a unique acidic treatment of multi-walled nanotubes. Spherical morphology with a narrow size distribution was confirmed by transmission electron microscopy studies. The room temperature Raman spectra showed a clear signature of D- and G-peaks at around 1350 and 1591 cm{sup −1}, respectively. Temperature dependent Raman scattering measurements were performed to understand the phonon dynamics and first order temperature coefficients related to the D- and G-peaks. The temperature dependent Raman spectra in a range of 83–473 K were analysed, where the D-peak was observed to show a red-shift with increasing temperature. The relative intensity ratio of D- to G-peaks also showed a significant rise with increasing temperature. Such a temperature dependent behaviour can be attributed to lengthening of the C-C bond due to thermal expansion in material. The estimated value of the thermal conductivity of GCNSs ∼0.97 W m{sup −1} K{sup −1} was calculated using Raman spectroscopy. In addition, the effect of pulsed laser treatment on the GCNSs was demonstrated by analyzing the Raman spectra of post irradiated samples.

  12. Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys

    Directory of Open Access Journals (Sweden)

    Thomas Gietzelt

    2016-11-01

    Full Text Available Normally, the weldability of aluminum alloys is ruled by the temperature range of solidification of an alloy according to its composition by the formation of hot cracks due to thermal shrinkage. However, for materials at nonequilibrium conditions, advantage can be taken by multiple phase formation, leading to an annihilation of temperature stress at the microscopic scale, preventing hot cracks even for alloys with extreme melting range. In this paper, several spray-compacted hypereutectic aluminum alloys were laser welded. Besides different silicon contents, additional alloying elements like copper, iron and nickel were present in some alloys, affecting the microstructure. The microstructure was investigated at the delivery state of spray-compacted material as well as for a wide range of welding speeds ranging from 0.5 to 10 m/min, respectively. The impact of speed on phase composition and morphology was studied at different disequilibrium solidification conditions. At high welding velocity, a close-meshed network of eutectic Al-Si-composition was observed, whereas the matrix is filled with nearly pure aluminum, helping to diminish the thermal stress during accelerated solidification. Primary solidified silicon was found, however, containing considerable amounts of aluminum, which was not expected from phase diagrams obtained at the thermodynamic equilibrium.

  13. Estudo de distribuição e morfologia dos melanócitos em pele com e sem exposição solar Melanocytes distribution and morphology analysis in skin with and without sun exposure

    Directory of Open Access Journals (Sweden)

    Daniela Mayumi Takano

    2010-02-01

    Full Text Available INTRODUÇÃO E OBJETIVOS: Acredita-se que a exposição solar possa alterar número, distribuição e morfologia dos melanócitos na pele humana, muitas vezes dificultando a interpretação de biópsias de pele, principalmente para o diagnóstico de lesões melanocíticas iniciais e para a avaliação precisa de margens de ressecção. O objetivo deste trabalho foi avaliar os melanócitos da pele humana em área exposta e não exposta ao sol. MÉTODOS: Realizada análise histológica de 60 fragmentos de biópsias de pele obtidas do antebraço (área fotoexposta e região glútea (área coberta de cadáveres do Serviço de Verificação de Óbitos de Recife-PE. A estatística foi realizada com o SPSS Windows versão 12.0. RESULTADOS: Observou-se um número bastante variável de melanócitos nos fragmentos de pele, com maior concentração destes na região do antebraço (área de maior fotoexposição (p INTRODUCTION AND OBJECTIVES: It is believed that sun exposure can change the number, distribution and morphology of melanocytes in human skin, which often hinders the interpretation of skin biopsies, mainly as to diagnosis of initial melanocytic lesions and accurate assessment of resection margins. Our objective was to evaluate melanocytes in sun-exposed and non-exposed skin. METHODS: It was conducted the histological analysis of 60 skin biopsy samples resected from cadaver forearm (sun-exposed skin and cadaver buttock (non-exposed skin from the Death Verification Service (Serviço de Verificação de Óbitos of Recife, state of Pernambuco. The statistical analysis was performed with SPSS Windows version 12.0. RESULTS: There was considerable variability in melanocyte density, with a higher concentration of these cells in sun-exposed areas (p < 0.001. There was also an irregular distribution of melanocytes along the epidermal basal layer, occasionally with cells arranged side by side. This confluence was identified with a higher frequency in sun

  14. Comparative evaluation of microhardness and morphology of permanent tooth enamel surface after laser irradiation and fluoride treatment - An in vitro study.

    Science.gov (United States)

    Kumar, Puneet; Goswami, Mridula; Dhillon, Jatinder Kaur; Rehman, Ferah; Thakkar, Deepti; Bharti, Kusum

    2016-10-01

    Background and aims: The aim of the study was to evaluate and compare the surface microhardness and surface morphology of permanent tooth enamel after Er,Cr:YSGG laser irradiation and Fluoride application. Materials and methods: One hundred and twenty premolars extracted for orthodontic purpose were used in the study and randomly divided into 6 groups. Group A was not subjected to any treatment. Group B was subjected to Er,Cr:YSGG laser irradiation. Group C was subjected to Er,Cr:YSGG laser irradiation followed by application of 2% NaF gel for 4 minutes. Group D was subjected to laser irradiation and 1.23% APF gel for 4 minutes. Group E was subjected to 2% NaF gel pretreatment technique followed by laser irradiation. Group F was subjected to 1.23% APF gel pretreatment technique followed by laser irradiation. All the test groups were subjected to microhardness testing and scanning electron microscope evaluation at 500 X and 1500 X. Results: All the treated groups showed an increase in microhardness value in comparison to the control group. The highest increase in microhardness was seen in Group F. Increase in microhardness values of Group B and Group D was not statistically significant as compared to Group A. Scanning Electron Micrographs showed few craters and fine porosities for Group A. These craters and porosities increased in size and often showed glass like appearance after laser irradiation. Conclusions: It can be suggested by means of present study that Er,Cr:YSGG laser irradiation alone or in combination with fluoride gel is an effective tool to provide resistance against the caries. Significantly higher resistance (p< 0.05) was seen when APF gel was used prior to Er,Cr:YSGG laser irradiation and this combination can act as an efficient tool for prevention against dental caries.

  15. SPERMATIC MORPHOLOGY ALTERATIONS IN BEEF BULLS SUPPLEMENTED OR NOT WITH ZINC IN MINERAL SALT ALTERAÇÕES NA MORFOLOGIA ESPERMÁTICA EM TOUROS DE CORTE COM E SEM SUPLEMENTAÇÃO DE ZINCO NA MISTURA MINERAL

    Directory of Open Access Journals (Sweden)

    Carlos Eurico Fernandes

    2009-12-01

    Full Text Available Seminal characteristics of bulls without Zn in the mineral supplementation (ZN-0, n=4, 0mg/Zn/kg/dia were compared with bulls contemporary with appropriate mineral supplementation (ZN-60FI, n=4, 60mg/Zn/kg/dia. The semen was evaluated biweekly, between 17 and 29 months of age. The prevalence of abnormal chromatin and morphometric profile (length, superior and inferior width (µm and area (µm2 of the sperm head were included in the analysis. ZN-0 bulls presented reduction of normal sperms in relation to ZN-60FI (63.3 ±2.88 x 74.5 ±2.83%, higher abnormal chromatin (16.7 ±2.05 x 9.3 ±0.81% and abnormal intermediate piece (9.3 ±0.81 x 3.2 ±0.80%, respectively. Abnormalities of intermediate piece were characterized by irregularities in the mitochondrial organization and rupture of the external dense fibers in electronic microscopy. The area of head sperm of ZN-60 bulls was lower (25.0 ±3.8 x 27.9 ±4.6, p <0.01 in relationship to ZN-0, respectively. We concluded that bulls born and maintained in the field conditions coming of herds with subclinic deficiency of Zn in the basal diet, are subject the reduction of the seminal quality and present larger frequency of intermediary piece abnormalities, sperm chromatin and variations on morphometrics measurements of head sperms. 


    KEY WORDS: Bovine, chromatin, nutrition, semen quality, sperm morphometry, zinc.

    rebanho sem Zn na suplementação mineral (ZN-0, n=4, 0mg/Zn/kg/dia foram comparadas com as de touros contemporâneos criados com suplementação adequada (ZN-60FI, n=4, 60mg/Zn/kg/dia. O sêmen foi colhido quinzenalmente, entre 17 e 29 meses de idade. Incluíram-se no exame a análise da cromatina espermática e o perfil morfométrico da cabeça espermática, com base no comprimento, largura superior e inferior (µm e área (µm2. Os touros do ZN-0 apresentaram redução de espermatozoides normais em relação ao ZN-60FI (62,4 ±2,88% x 74,5 ±2

  16. Detection of morphological changes in cliff face surrounding a waterfall using terrestrial laser scanning and unmanned aerial system

    Science.gov (United States)

    Hayakawa, Yuichi S.; Obanawa, Hiroyuki

    2015-04-01

    Waterfall or bedrock knickpoint appears as an erosional front in bedrock rivers forming deep v-shaped valley downstream. Following the rapid fluvial erosion of waterfall, rockfalls and gravita-tional collapses often occur in surrounding steep cliffs. Although morphological changes of such steep cliffs are sometimes visually observed, quantitative and precise measurements of their spatio-temporal distribution have been limited due to the difficulties in direct access to such cliffs if with classical measurement methods. However, for the clarification of geomorphological processes oc-curring in the cliffs, multi-temporal mapping of the cliff face at a high resolution is necessary. Re-mote sensing approaches are therefore suitable for the topographic measurements and detection of changes in such inaccessible cliffs. To achieve accurate topographic mapping of cliffs around a wa-terfall, here we perform multi-temporal terrestrial laser scanning (TLS), as well as structure-from-motion multi-view stereo (SfM-MVS) photogrammetry based on unmanned aerial system (UAS). The study site is Kegon Falls in central Japan, having a vertical drop of surface water from top of its overhanging cliff, as well as groundwater outflows from its lower portions. The bedrock is composed of alternate layers of andesite lava and conglomerates. Minor rockfalls in the cliffs are often ob-served by local people. The latest major rockfall occurred in 1986, causing ca. 8-m upstream propa-gation of the waterfall lip. This provides a good opportunity to examine the changes in the surround-ing cliffs following the waterfall recession. Multi-time point clouds were obtained by TLS measure-ment over years, and the three-dimensional changes of the rock surface were detected, uncovering the locus of small rockfalls and gully developments. Erosion seems particularly frequent in relatively weak the conglomerates layer, whereas small rockfalls seems to have occurred in the andesite layers. Also, shadows in the

  17. Morphological evolution of primary TiC carbide in laser clad TiC reinforced FeAl intermetallic composite coating

    Institute of Scientific and Technical Information of China (English)

    陈瑶; 王华明

    2003-01-01

    The novel rapidly solidified TiC/FeAl composite coatings were fabricated by laser cladding on the substrate of 1Cr18Ni9Ti stainless steel, particular emphasis has been placed on the growth morphologies of TiC carbide and its growth mechanism under a constant solidification conditions. Results show that the growth morphology of TiC carbide strongly depends upon the nucleation process and mass transportation process of TiC forming elements in laser melt pool. With increasing amount of titanium and carbon in melt pool, the growth morphology of TiC carbide changes from block-like to star-like and well-developed dendrite. As the amount of titanium and carbon increases further, TiC carbide particles are found to be irregular polyhedral block. Although the growth morphologies of TiC are various,their advancing fronts are all faceted, illustrating that TiC carbide grows by the mechanism of lateral ledge growth.

  18. Secondary emission monitor (SEM) grids.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    A great variety of Secondary Emission Monitors (SEM) are used all over the PS Complex. At other accelerators they are also called wire-grids, harps, etc. They are used to measure beam density profiles (from which beam size and emittance can be derived) in single-pass locations (not on circulating beams). Top left: two individual wire-planes. Top right: a combination of a horizontal and a vertical wire plane. Bottom left: a ribbon grid in its frame, with connecting wires. Bottom right: a SEM-grid with its insertion/retraction mechanism.

  19. Irradiation of dental enamel with Q-switched lambda = 355-nm laser pulses: surface morphology, fluoride adsorption, and adhesion to composite resin.

    Science.gov (United States)

    Wheeler, Cameron R; Fried, Daniel; Featherstone, John D B; Watanabe, Larry G; Le, Charles Q

    2003-01-01

    Lasers can be used to modify the chemical composition of dental enamel to increase the bond strength to restorative materials and to render the mineral phase more resistant to acid dissolution. Previous studies have suggested a synergistic relationship between CO(2) laser irradiation and fluoride treatment on increased resistance to acid dissolution. In this study a near-UV laser operating with lambda = 355-nm laser pulses of 3-5 nanoseconds duration was used to modify the surface morphology of dental enamel to increase the bond strength to restorative materials and increase the uptake of topical fluoride to render the surface more resistant to acid dissolution. We hypothesize that the short UV laser pulses are primarily absorbed by protein and lipid localized between the enamel prisms resulting in removal of intact mineral effectively etching the surface without thermal modification of the mineral phase. Such modification is likely to increase the permeability of the enamel surface and the subsequent absorption of fluoride. In addition, there is an increase in surface roughness without the formation of a layer of loosely adherent, thermally modified enamel that increases the bond strength to composite restorative materials. The surfaces of blocks of bovine enamel, 5 x 5 mm(2), were uniformly irradiated by 355-nm laser pulses and subsequently bonded to composite. The shear bond test was used to assess the bond strength of non-irradiated blocks (negative control), acid etched blocks (positive control), and laser irradiated blocks. The resistance to acid dissolution was evaluated using controlled surface dissolution experiments on irradiated samples, irradiated samples exposed to topical fluoride, and non-irradiated control samples with and without fluoride. The laser surface treatments significantly increased the shear-bond strength of enamel to composite, to a level exceeding 20 MPa which was significantly more than the non-irradiated control samples and

  20. SEM: A Cultural Change Agent

    Science.gov (United States)

    Barnes, Bradley; Bourke, Brian

    2015-01-01

    The authors advance the concept that institutional culture is a purposeful framework by which to view SEM's utility, particularly as a cultural change agent. Through the connection of seemingly independent functions of performance and behavior, implications emerge that deepen the understanding of the influence of culture on performance outcomes…

  1. [Effects of Nd: YAG laser irradiation on the root surfaces and adhesion of Streptococcus mutans].

    Science.gov (United States)

    Yuanhong, Li; Zhongcheng, Li; Mengqi, Luo; Daonan, Shen; Shu, Zhang; Shu, Meng

    2016-12-01

    This study aimed to evaluate the effects of treatment with different powers of Nd: YAG laser irradiation on root surfaces and Streptococcus mutans (S. mutans) adhesion. Extracted teeth because of severe periodontal disease were divided into the following four groups: control group, laser group 1, laser group 2, and laser group 3. After scaling and root planning, laser group 1, laser group 2, and laser group 3 were separately treated with Nd: YAG laser irradiation (4/6/8 W, 60 s); however, the control group did not receive the treatment. Scanning electron microscopy (SEM) was used to determine the morphology. S. mutans were cultured with root slices from each group. Colony forming unit per mL (CFU·mL⁻¹) was used to count and compare the amounts of bacteria adhesion among groups. SEM was used to observe the difference of bacteria adhesion to root surfaces between control group (scaling) and laser group 2 (6 W, 60 s), thereby indicating the different bacteria adhesions because of different treatments. Morphology alterations indicated that root surfaces in control group contain obvious smear layer, debris, and biofilm; whereas the root surfaces in laser group contain more cracks with less smear layer and debris. The bacteria counting indicated that S. mutans adhesion to laser group was weaker than that of control group (P0.05) was observed. Morphology alterations also verified that S. mutans adhesion to laser group 2 (6 W, 60 s) was weaker than that of control group (scaling). This study demonstrated that Nd: YAG laser irradiation treatment after scaling can reduce smear layer, debris, and biofilm on the root surfaces as compared with conventional scaling. The laser treatment reduces the adhesion of S. mutans as well. However, Nd: YAG laser irradiation can cause cracks on the root surfaces. In this experiment, the optimum laser power of 6 W can thoroughly remove the smear layer and debris, as well as relatively improve the control of thermal damagee.

  2. Synergistic effects of hydrogen plasma exposure, pulsed laser heating and temperature on rhodium surfaces

    NARCIS (Netherlands)

    Marot, L.; De Temmerman, G.; Doerner, R. P.; Umstadter, K.; Wagner, R. S.; Mathys, D.; Duggelin, M.; Meyer, E.

    2013-01-01

    The combined effect of hydrogen plasma exposure and surface heating, either continuous or by short laser pulses (5 ns), on the surface morphology of rhodium layers has been studied. Investigations were performed by reflectivity measurements, scanning electron microscopy (SEM), X-ray

  3. Femtosecond laser nanostructuring of silver film

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Ye; Ma, Guohong [Shanghai University, Department of Physics, Shanghai (China); Shanghai University, Laboratory for Microstructures, Shanghai (China); He, Min; Bian, Huadong; Yan, Xiaona [Shanghai University, Department of Physics, Shanghai (China); Lu, Bo [Shanghai University, Laboratory for Microstructures, Shanghai (China)

    2012-03-15

    In this paper, we report an evolution of surface morphology of silver film irradiated by a 1 kHz femtosecond laser. By SEM observations, it is noted that different nanostructures with respective surface features depend highly on the number of pulses and the laser fluence. Especially when the laser fluence is below the threshold fluence of film breakdown, a textured nanostructure including many nanobumps and nanocavities will appear on the surface of silver film. In order to determine an optimal regime for nanostructuring silver film and to further study the underlying mechanism, we perform a quantitative analysis of laser fluence and pulse number. The results show that this nanostructure formation should be due to a sequential process of laser melting, vapor bubbles bursting, heat stress confinement, and subsequent material redistribution. As a potential application, we find this nanostructured silver film can be used as the active substrate for surface enhanced Raman scattering effect. (orig.)

  4. The observation of a transient surface morphology in the femtosecond laser ablation process by using the soft x-ray laser probe

    Science.gov (United States)

    Hasegawa, Noboru; Nishikino, Masaharu; Tomita, Takuro; Ohnishi, Naofumi; Ito, Atsushi M.; Eyama, Takashi; Kakimoto, Naoya; Idutsu, Rui; Minami, Yasuo; Baba, Motoyoshi; Faenov, Anatoly Y.; Inogamov, Nail A.; Kawachi, Tetsuya; Yamagiwa, Mitsuru; Suemoto, Tohru

    2015-09-01

    We have improved a soft x-ray laser (SXRL) interferometer synchronized with a Ti:Sapphire laser pulse to observe the single-shot imaging of the nano-scaled structure dynamics of the laser induced materials. By the precise imaging optics and double time fiducial system having been installed, the lateral resolution on the sample surface and the precision of the temporal synchronization between the SXRL and Ti:Sapphire laser pulses were improved to be 700 nm and 2 ps, respectively. By using this system, the initial stage (t < 200 ps) of the ablation process of the Pt surface pumped by 80 fs Ti:Sapphire laser pulse was observed by the comparison between the soft x-ray reflective image and interferogram. We have succeeded in the direct observation of the unique ablation process around the ablation threshold such as the rapid increase of the surface roughness and surface vibration.

  5. Influence of multi-wavelength laser irradiation of enamel and dentin surfaces at 0.355, 2.94, and 9.4 μm on surface morphology, permeability, and acid resistance.

    Science.gov (United States)

    Chang, Nai-Yuan N; Jew, Jamison M; Simon, Jacob C; Chen, Kenneth H; Lee, Robert C; Fried, William A; Cho, Jinny; Darling, Cynthia L; Fried, Daniel

    2017-07-12

    Ultraviolet (UV) and infrared (IR) lasers can be used to specifically target protein, water, and mineral, respectively, in dental hard tissues to produce varying changes in surface morphology, permeability, reflectivity, and acid resistance. The purpose of this study was to explore the influence of laser irradiation and topical fluoride application on the surface morphology, permeability, reflectivity, and acid resistance of enamel and dentin to shed light on the mechanism of interaction and develop more effective treatments. Twelve bovine enamel surfaces and twelve bovine dentin surfaces were irradiated with various combinations of lasers operating at 0.355 (Freq.-tripled Nd:YAG (UV) laser), 2.94 (Er:YAG laser), and 9.4 μm (CO2 laser), and surfaces were exposed to an acidulated phosphate fluoride gel and an acid challenge. Changes in the surface morphology, acid resistance, and permeability were measured using digital microscopy, polarized light microscopy, near-IR reflectance, fluorescence, polarization sensitive-optical coherence tomography (PS-OCT), and surface dehydration rate measurements. Different laser treatments dramatically influenced the surface morphology and permeability of both enamel and dentin. CO2 laser irradiation melted tooth surfaces. Er:YAG and UV lasers, while not melting tooth surfaces, showed markedly different surface roughness. Er:YAG irradiation led to significantly rougher enamel and dentin surfaces and led to higher permeability. There were significant differences in acid resistance among the various treatment groups. Surface dehydration measurements showed significant changes in permeability after laser treatments, application of fluoride and after exposure to demineralization. CO2 laser irradiation was most effective in inhibiting demineralization on enamel while topical fluoride was most effective for dentin surfaces. Lasers Surg. Med. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  6. Modified surface morphology in surface ablation of cobalt-cemented tungsten carbide with pulsed UV laser radiation

    Science.gov (United States)

    Li, Tiejun; Lou, Qihong; Dong, Jingxing; Wei, Yunrong; Liu, Jingru

    2001-03-01

    Surface ablation of cobalt-cemented tungsten carbide hardmetal has been carried out in this work using a 308 nm, 20 ns XeCl excimer laser. The influence of ablation rate, surface roughness, surface micromorphology as well as surface phase structure on laser conditions including laser irradiance and pulse number have been investigated. The experimental results showed that the ablation rate and surface roughness were controlled by varying the number of pulses and laser irradiance. The microstructure and crystalline structure of irradiated surface layer varied greatly with different laser conditions. After 300 shots of laser irradiation at irradiance of 125 MW/cm 2, the surface micromorphology characterizing a uniform framework pattern of "hill-valleys". With the increment of laser shots at laser irradiance of 125 MW/cm 2, the microstructure of cemented tungsten carbide transformed from original polygon grains with the size of 3 μm to interlaced large and long grains after 300 shots of laser irradiation, and finally to gross grains with the size of 10 μm with clear grain boundaries after 700 shots. The crystalline structure of irradiated area has partly transformed from original WC to β-WC 1- x, then to α-W 2C and CW 3, and finally to W crystal. At proper laser irradiance and pulse number, cobalt binder has been selectively removed from the surface layer of hardmetal. It has been demonstrated that surface ablation with pulsed UV laser should be a feasible way to selectively remove cobalt binder from surface layer of cemented tungsten carbide hardmetal.

  7. Morphological change study on root surfaces treated with curettes, sonic instruments or Er:YAG laser; Estudo in vitro da alteracao morfologica em superficie radicular tratada com curetas, aparelho ultrasonico ou com laser de Er:YAG

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes Filho, Arlindo Lopes

    2004-07-01

    Periodontal disease is caused by dental plaque and dental calculus on roots surfaces, specially on cervical areas. As dental plaque is the main cause and dental calculus a secondary one, it is practically impossible to separate one factor to the other one. In order to get periodontal tissue health it is necessary to eliminate dental plaque and calculus from root surfaces. In this sense, Er:YAG laser comes in as an excellent way to control periodontal disease, not only, by removing calculus and dental plaque but also for its bacteria reduction. The aim of this study is to compare, by S.E.M., root surfaces changing when they are treated with curettes and ultrasonic scaling or Er:YAG laser irradiation with two different energy levels of 60 mJ/pulse and 100 mJ/pulse and repetition tax of 10 Hz (in the display). It is also objective of this study to check a possible thermic damage to pulp tissue when the roots surfaces are irradiated with Er:YAG laser. We used for this study, five human dental roots, each one of them were cut into four samples, giving us a total of twenty samples, which were divided in five groups of four samples each one. The control group, we did not indicated any kind of treatment. The first group, the roots samples were scaled and planned with Gracey curettes 5/6 and 7/8. The second group, the roots samples were treated with ultrasonic instruments. The third group was irradiated with Er:YAG laser using 60 mJ/pulse , 10 Hz and energy density of 4 J/cm{sup 2} (approximated). The fourth group was irradiated with Er:YAG laser using 100 mJ/pulse, 10 Hz and energy density of 7 J/cm{sup 2} (approximated). The results analysis showed that roots scaling either with Gracey curettes or with ultrasonic instruments created smear layer covering roots surfaces; roots surfaces irradiated with Er:YAG laser showed few roughness in the third group; roots surfaces irradiated with Er:YAG laser showed no smear layer and the Er:YAG laser irradiation did not bring any

  8. In vitro study of morphological and chemical modification threshold of bovine dental enamel irradiated by the holmium laser; Estudo in vitro das alteracoes morfologicas e quimicas do esmalte dental bovino irradiado pelo laser de holmio

    Energy Technology Data Exchange (ETDEWEB)

    Eduardo, Patricia Lerro de Paula

    2001-07-01

    The aim of this study is to investigate the Ho:YLF laser effects on the dental enamel surface with regards to its morphology, thermal variations during its irradiation in the pulp chamber and its increased resistance to demineralization through quantitative analysis of calcium and phosphorous atoms reactive concentrations in samples. Twenty samples of bovine enamel were used and divided in four groups: control - acidulated phosphate fluoride (APF) application followed by demineralization treatment with lactic acid; irradiation with Ho:YLF laser (100 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid; irradiation with Ho:YLF laser (350 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid: and irradiation with Ho:YLF laser ( 450 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid. Ali samples were quantified according to their calcium and phosphorous atoms relative concentrations before and after the treatments above. X-Ray fluorescence spectrochemical analysis and scanning electron microscopy were carried out. It was observed an increase on the calcium and phosphorous atoms concentration ratio and therefore the enamel demineralization reduction as a result of the lactic acid treatment in the samples irradiated with the holmium laser followed by the APF application. In order to evaluate the feasibility of this study for clinical purposes, morphological changes caused by the holmium laser irradiation were analyzed. Such modifications were characterized by melted and re-solidified regions of the enamel with consequent changes on its permeability and solubility. Temperature changes of ten human pre-molars teeth irradiated with 350 J/cm{sup 2} and 450 J/cm{sup 2} were also monitored in the pulp chamber in real time. Temperature increases over 4,20 C did not occur. The results obtained from this study along with the results from previous

  9. UV laser ablation patterns in intraocular lenses

    Science.gov (United States)

    Lagiou, D. P.; Evangelatos, Ch.; Apostolopoulos, A.; Spyratou, E.; Bacharis, C.; Makropoulou, M.; Serafetinides, A. A.

    2013-03-01

    The aim of this work is to investigate the effect of UV solid state laser radiation on intraocular lens (IOL) polymer surfaces as an alternative method to conventional surface shaping techniques for IOLs customization. Laser ablation experiments were performed on PMMA plates and commercially available hydrophobic and hydrophilic acrylic IOLs with the 5th harmonic of a Q-switched Nd:YAG laser (λ=213 nm). Circular arrays of holes were drilled on the polymer surface, covering the centre and the peripheries of the IOL. The morphology of the ablated IOL surface was examined with a conventional optical microscope (Leitz GMBH Wetzlar) and with a scanning electron microscope (SEM, Fei - Innova Nanoscope) at various laser parameters. Quantitative measurements of ablation rates were performed with a contact profilometer (Dektak-150), in which a mechanical stylus scanned across the surface of gold-coated IOLs (after SEM imaging) to measure variationsF in surface height. Laser interaction with IOLs depends on optical and mechanical material properties, in addition to laser radiation parameters. The exact ablation mechanism is discussed. Some polymer materials, depending on their properties, are more susceptible to the photothermal mechanism than the photochemical one or vice versa. In summary, every IOL polymer exhibits specific attributes in its interaction with the 5th harmonic of Nd:YAG laser.

  10. International Conference on SEMS 2012

    CERN Document Server

    Liu, Chuang; Scientific explanation and methodology of science; SEMS 2012

    2014-01-01

    This volume contains the contributed papers of invitees to SEMS 2012 who have also given talks at the conference. The invitees are experts in philosophy of science and technology from Asia (besides China), Australia, Europe, Latin America, North America, as well as from within China. The papers in this volume represent the latest work of each researcher in his or her expertise; and as a result, they give a good representation of the cutting-edge researches in diverse areas in different parts of the world.

  11. Resonant Infrared Matrix Assisted Pulsed Laser Deposition of Polymers: Improving the Morphology of As-Deposited Films

    Science.gov (United States)

    Bubb, Daniel; Papantonakis, Michael; Collins, Brian; Brookes, Elijah; Wood, Joshua; Gurudas, Ullas

    2008-03-01

    Resonant infrared matrix assisted pulsed laser deposition has been used to deposit thin films of PMMA, a widely used industrial polymer. This technique is similar to conventional pulsed laser deposition, except that the polymer to be deposited is dissolved in a solvent and the solution is frozen before ablation in a vacuum chamber. The laser wavelength is absorbed by a vibrational band in the frozen matrix. The polymer lands on the substrate to form a film, while the solvent is pumped away. Our preliminary results show that the surface roughness of the as-deposited films depends strongly on the differential solubility radius, as defined by Hansen solubility parameters of the solvent and the solubility radius of the polymer. Our results will be compared with computational and experimental studies of the same polymer using a KrF (248 nm) laser. The ejection mechanism will be discussed as well as the implications of these results for the deposition of smooth high quality films.

  12. Morphology of resin-dentin interfaces after Er,Cr:YSGG laser and acid etching preparation and application of different bonding systems.

    Science.gov (United States)

    Beer, Franziska; Buchmair, Alfred; Körpert, Wolfram; Marvastian, Leila; Wernisch, Johann; Moritz, Andreas

    2012-07-01

    The goal of this study was to show the modifications in the ultrastructure of the dentin surface morphology following different surface treatments. The stability of the adhesive compound with dentin after laser preparation compared with conventional preparation using different bonding agents was evaluated. An Er,Cr:YSGG laser and 36% phosphoric acid in combination with various bonding systems were used. A total of 100 caries-free human third molars were used in this study. Immediately after surgical removal teeth were cut using a band saw and 1-mm thick dentin slices were created starting at a distance of 4 mm from the cusp plane to ensure complete removal of the enamel. The discs were polished with silicon carbide paper into rectangular shapes to a size of 6 × 4 mm (±0,2 mm).The discs as well as the remaining teeth stumps were stored in 0.9% NaCl at room temperature. The specimens were divided into three main groups (group I laser group, group II etch group, group III laser and etch group) and each group was subdivided into three subgroups which were allocated to the different bonding systems (subgroup A Excite, subgroup B Scotchbond, subgroup C Syntac). Each disc and the corresponding tooth stump were treated in the same way. After preparation the bonding composite material was applied according to the manufacturers' guidelines in a hollow tube of 2 mm diameter to the disc as well as to the corresponding tooth stump. Shear bond strength testing and environmental scanning electron microscopy were used to assess the morphology and stability of the resin-dentin interface. The self-etching bonding system showed the highest and the most constant shear values in all three main groups, thus enabling etching with phosphoric acid after laser preparation to be avoided. Thus we conclude that laser preparation creates a surface texture that allows prediction of the quality of the restoration without the risk of negative influences during the following treatment steps. This

  13. Fs-laser processing of medical grade polydimethylsiloxane (PDMS)

    Science.gov (United States)

    Atanasov, P. A.; Stankova, N. E.; Nedyalkov, N. N.; Fukata, N.; Hirsch, D.; Rauschenbach, B.; Amoruso, S.; Wang, X.; Kolev, K. N.; Valova, E. I.; Georgieva, J. S.; Armyanov, St. A.

    2016-06-01

    Medical grade polydimethylsiloxane (PDMS) elastomer is a biomaterial widely used in medicine and high-tech devices, e.g. MEMS and NEMS. In this work, we report an experimental investigation on femtosecond laser processing of PDMS-elastomer with near infrared (NIR), visible (VIS) and ultraviolet (UV) pulses. High definition trenches are produced by varying processing parameters as laser wavelength, pulse duration, fluence, scanning speed and overlap of the subsequent pulses. The sample surface morphology and chemical composition are investigated by Laser Microscopy, SEM and Raman spectroscopy, addressing the effects of the various processing parameters through comparison with the native materials characteristics. For all the laser pulse wavelengths used, the produced tracks are successfully metalized with Ni via electro-less plating method. We observe a negligible influence of the time interval elapsed between laser treatment and metallization process. Our experimental findings suggest promising perspectives of femtosecond laser pulses in micro- and nano-fabrication of hi-tech PDMS devices.

  14. Morphology and topography of perovskite solar cell films ablated and scribed with short and ultrashort laser pulses

    Science.gov (United States)

    Bayer, Lukas; Ehrhardt, Martin; Lorenz, Pierre; Pisoni, Stefano; Buecheler, Stephan; Tiwari, Ayodhya N.; Zimmer, Klaus

    2017-09-01

    The unique properties of halide perovskites are suitable for low-cost high-efficiency photovoltaic applications. For commercialization of this technology, it is pivotal to upscale towards solar modules. Monolithic interconnection of solar cells is a necessary step for realization of thin-film solar modules and the laser scribing of the constituent layers with well-defined profiles of high accuracy is a promising approach for high speed processing. Here the laser ablation and scribing of methylammonium lead iodide perovskite (CH3NH3PbI3: MAPbI3) layers are investigated. Nanosecond (ns) and picosecond (ps) laser pulses were used to ablate and scribe MAPbI3 films on FTO/glass by irradiation from the film- and the glass-side. Depending on the irradiation configuration laser ablation or lift-off delamination was determined to be the dominating mechanism of thin-film removal. Various surface modifications such as film smoothening and decomposition of the MAPbI3 have been observed, especially when nanosecond laser pulses are used. The complete removal of the MAPbI3, film without damaging the FTO/substrate, has been achieved for all studied laser sources.

  15. Quantitative roughness characterization and 3D reconstruction of electrode surface using cyclic voltammetry and SEM image

    Energy Technology Data Exchange (ETDEWEB)

    Dhillon, Shweta; Kant, Rama, E-mail: rkant@chemistry.du.ac.in

    2013-10-01

    Area measurements from cyclic voltammetry (CV) and image from scanning electron microscopy (SEM) are used to characterize electrode statistical morphology, 3D surface reconstruction and its electroactivity. SEM images of single phased materials correspond to two-dimensional (2D) projections of 3D structures, leading to an incomplete characterization. Lack of third dimension information in SEM image is circumvented using equivalence between denoised SEM image and CV area measurements. This CV-SEM method can be used to estimate power spectral density (PSD), width, gradient, finite fractal nature of roughness and local morphology of the electrode. We show that the surface morphological statistical property like distribution function of gradient can be related to local electro-activity. Electrode surface gradient micrographs generated here can provide map of electro-activity sites. Finally, the densely and uniformly packed small gradient over the Pt-surface is the determining criterion for high intrinsic electrode activity.

  16. A new adaptive method to filter terrestrial laser scanner point clouds using morphological filters and spectral information to conserve surface micro-topography

    Science.gov (United States)

    Rodríguez-Caballero, E.; Afana, A.; Chamizo, S.; Solé-Benet, A.; Canton, Y.

    2016-07-01

    Terrestrial laser scanning (TLS), widely known as light detection and ranging (LiDAR) technology, is increasingly used to provide highly detailed digital terrain models (DTM) with millimetric precision and accuracy. In order to generate a DTM, TLS data has to be filtered from undesired spurious objects, such as vegetation, artificial structures, etc., Early filtering techniques, successfully applied to airborne laser scanning (ALS), fail when applied to TLS data, as they heavily smooth the terrain surface and do not retain their real morphology. In this article, we present a new methodology for filtering TLS data based on the geometric and radiometric properties of the scanned surfaces. This methodology was built on previous morphological filters that select the minimum point height within a sliding window as the real surface. However, contrary to those methods, which use a fixed window size, the new methodology operates under different spatial scales represented by different window sizes, and can be adapted to different types and sizes of plants. This methodology has been applied to two study areas of differing vegetation type and density. The accuracy of the final DTMs was improved by ∼30% under dense canopy plants and over ∼40% on the open spaces between plants, where other methodologies drastically underestimated the real surface heights. This resulted in more accurate representation of the soil surface and microtopography than up-to-date techniques, eventually having strong implications in hydrological and geomorphological studies.

  17. Metal nanostructures with complex surface morphology: The case of supported lumpy Pd and Pt nanoparticles produced by laser processing of metal films

    Science.gov (United States)

    Ruffino, F.; Maugeri, P.; Cacciato, G.; Zimbone, M.; Grimaldi, M. G.

    2016-09-01

    In this work we report on the formation of lumpy Pd and Pt nanoparticles on fluorine-doped tin oxide/glass (FTO/glass) substrate by a laser-based approach. In general, complex-surface morphology metal nanoparticles can be used in several technological applications exploiting the peculiarities of their physical properties as modulated by nanoscale morphology. For example plasmonic metal nanoparticles presenting a lumpy morphology (i.e. larger particles coated on the surface by smaller particles) can be used in plasmonic solar cell devices providing broadband scattering enhancement over the smooth nanoparticles leading, so, to the increase of the device efficiency. However, the use of plasmonic lumpy nanoparticles remains largely unexplored due to the lack of simply, versatile, low-cost and high-throughput methods for the controllable production of such nanostructures. Starting from these considerations, we report on the observation that nanoscale-thick Pd and Pt films (17.6 and 27.9 nm, 12.1 and 19.5 nm, respectively) deposited on FTO/glass surface irradiated by nanosecond pulsed laser at fluences E in the 0.5-1.5 J/cm2 range, produce Pd and Pt lumpy nanoparticles on the FTO surface. In addition, using scanning electron microscopy analyses, we report on the observation that starting from each metal film of fixed thickness h, the fraction F of lumpy nanoparticles increases with the laser fluence E and saturates at the higher fluences. For each fixed fluence, F was found higher starting from the Pt films (at each starting film thickness h) with respect to the Pd films. For each fixed metal and fluence, F was found to be higher decreasing the starting thickness of the deposited film. To explain the formation of the lumpy Pd and Pt nanoparticles and the behavior of F as a function of E and h both for Pd and Pt, the thermodynamic behavior of the Pd and Pt films and nanoparticles due to the interaction with the nanosecond laser is discussed. In particular, the

  18. Evaluation of dental pulp repair using low level laser therapy (688 nm and 785 nm) morphologic study in capuchin monkeys

    Science.gov (United States)

    Pretel, H.; Oliveira, J. A.; Lizarelli, R. F. Z.; Ramalho, L. T. O.

    2009-02-01

    The aim of this study was to evaluate the hypothesis that low-level laser therapy (LLLT) 688 nm and 785 nm accelerate dentin barrier formation and repair process after traumatic pulp exposure. The sample consisted of 45 premolars of capuchin monkeys (Cebus apella) with pulp exposure Class V cavities. All premolars were treated with calcium hydroxide (Ca(OH)2), divided in groups of 15 teeth each, and analyzed on 7th, 25th, and 60th day. Group GI - only Ca(OH)2, GII - laser 688 nm, and GIII - laser 785 nm. Laser beam was used in single and punctual dose with the parameters: continuous, 688 nm and 785 nm wavelength, tip's area of 0.00785 cm2, power 50 mW, application time 20 s, dose 255 J/cm2, energy 2 J. Teeth were capped with Ca(OH)2, Ca(OH)2 cement and restored with amalgam. All groups presented pulp repair. On 25th day the thickness of the formed dentin barrier was different between the groups GI and GII (p < 0.05) and between groups GI and GIII (p < 0.01). On 60th day there was difference between GI and GIII (p < 0.01). It may be concluded that, LLLT 688 nm and 785 nm accelerated dentin barrier formation and consequently pulp repair process, with best results using infrared laser 785 nm.

  19. Morphology and transmittance of porous alumina on glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Guo Peitao, E-mail: guopeitao@hotmail.com [Wuhan University of Technology. Wuhan (China); Xia Zhilin [Wuhan University of Technology. Wuhan (China); Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education, Xiangtan (China); Xue Yiyu [Wuhan University of Technology. Wuhan (China); Huang Caihua [China Three Gorges University, Yichang (China); Zhao Lixin [Wuhan University of Technology. Wuhan (China)

    2011-02-01

    The porous optical film has higher threshold of laser-induced damage than densified films, for the study of mechanism of laser-induced damage of porous optical film with ordered pore structure. Porous anodic alumina (PAA) film with high transmittance on glass substrate has been prepared. Aluminum film was deposited on glass substrate by means of resistance and electron beam heat (EBH) evaporation. Porous alumina was prepared in oxalic acid solution under different anodizing conditions. At normal incidence, the optical transmittance spectrum over 300-1000 nm spectra region was obtained by spectrophotometer. SEM was introduced to analysis the morphology of the porous alumina film. The pore aperture increased with the increase of anodizing voltage, which resulted in a rapid decrease of the pore concentration and the optical thickness of porous alumina film. Damage morphology of porous alumina film is found to be typically defects initiated, and the defect is the pore presented on the film.

  20. Time-dependent effects of low-level laser therapy on the morphology and oxidative response in the skin wound healing in rats.

    Science.gov (United States)

    Gonçalves, Reggiani Vilela; Novaes, Rômulo Dias; Cupertino, Marli do Carmo; Moraes, Bruna; Leite, João Paulo Viana; Peluzio, Maria do Carmo Gouveia; Pinto, Marcus Vinicius de Mello; da Matta, Sérgio Luis Pinto

    2013-02-01

    This study aims to investigate the effect of different energy densities provided by low-level laser therapy (LLLT) on the morphology of scar tissue and the oxidative response in the healing of secondary intention skin wounds in rats. Twenty-four male adult Wistar rats were used. Skin wounds were made on the backs of the animals, which were randomized into three groups of eight animals each as follows, 0.9% saline (control); laser GaAsAl 30 J/cm(2) (L30); laser GaAsAl 90 J/cm(2) (L90). The experiment lasted 21 days. Every 7 days, the wound contraction index (WCI) was calculated and tissue from different wounds was removed to assess the proportion of cells and blood vessels, collagen maturation index (CMI), thiobarbituric acid reactive substance (TBARS) levels and catalase activity (CAT). On the 7th and 14th days, the WCI and the proportion of cells were significantly higher in groups L30 and L90 compared to the control (p oxidative status of wounded tissue, constituting a possible mechanism through which the LLLT exerts its effects in the initial phases of tissue repair.

  1. Effect of external applied steady magnetic field on the morphology of laser welding joint of 4-mm 2024 aluminum alloy

    Science.gov (United States)

    Zhan, Xiaohong; Zhou, Junjie; Sun, Weihua; Chen, Jicheng; Wei, Yanhong

    2017-01-01

    Additional external steady magnetic fields were applied to investigate the influence of a steady magnetic field aligned perpendicular to the welding direction during laser beam welding of 2024 aluminum alloy. The flow pattern in the molten pool and the weld seam geometry were significantly changed by the induced Lorentz force distribution in the liquid metal. It revealed that the application of a steady magnetic field to laser beam welding was helpful to the suppression of the characteristic wineglass-shape and the depth-to-width ratio because of the Marangoni convection. The microstructures and component distributions at various laser power and magnetic field intensity were analyzed too. It was indicated that the suppression of the Marangoni convection by Lorentz force was beneficial to accumulation of component and grain coarsening near the fusion line.

  2. [Lasers].

    Science.gov (United States)

    Passeron, T

    2012-11-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  3. Lasers.

    Science.gov (United States)

    Passeron, T

    2012-12-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  4. Effect of Nd:YAG laser beam welding on weld morphology and mechanical properties of Ti-6Al-4V butt joints and T-joints

    Science.gov (United States)

    Kashaev, Nikolai; Ventzke, Volker; Fomichev, Vadim; Fomin, Fedor; Riekehr, Stefan

    2016-11-01

    A Nd:YAG single-sided laser beam welding process study for Ti-6Al-4V butt joints and T-joints was performed to investigate joining techniques with regard to the process-weld morphology relationship. An alloy compatible filler wire was used to avoid underfills and undercuts. The quality of the butt joints and T-joints was characterized in terms of weld morphology, microstructure and mechanical properties. Joints with regular shapes, without visible cracks, pores, and geometrical defects were achieved. Tensile tests revealed high joint integrity in terms of strength and ductility for both the butt joint and T-joint geometries. Both the butt joints and T-joints showed base material levels of strength. The mechanical performance of T-joints was also investigated using pull-out tests. The performance of the T-joints in such tests was sensitive to the shape and morphology of the welds. Fracture always occurred in the weld without any plastic deformation in the base material outside the weld.

  5. Fs-laser processing of medical grade polydimethylsiloxane (PDMS)

    Energy Technology Data Exchange (ETDEWEB)

    Atanasov, P.A., E-mail: paatanas@ie.bas.bg [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsaridradsko shose Blvd., Sofia 1784 (Bulgaria); Stankova, N.E.; Nedyalkov, N.N. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsaridradsko shose Blvd., Sofia 1784 (Bulgaria); Fukata, N. [International Centre for Materials for NanoArchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1Namiki, Tsukuba 305-0044 (Japan); Hirsch, D.; Rauschenbach, B. [Leibniz Institute of Surface Modification (IOM), Permoserstrasse 15, D-04318 Leipzig (Germany); Amoruso, S.; Wang, X. [Dipartimento di Fisica Università degli Studi di Napoli Federico II and CNR-SPIN, Complesso Universitario di Monte S.Angelo, Via Cintia, I-80126 Napoli (Italy); Kolev, K.N.; Valova, E.I.; Georgieva, J.S.; Armyanov, St.A. [Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria)

    2016-06-30

    Highlights: • Fs-laser (263, 527 and 1055 nm) processing of PDMS-elastomer is studied. • High quality trenches are produced on the PDMS surface. • The trenches are analyzed by Laser Microscope and by μ-Raman spectrometry. • Selective Ni metallization of the trenches is accomplished via electro-less plating. • The metalized trenches are studied by SEM. - Abstract: Medical grade polydimethylsiloxane (PDMS) elastomer is a biomaterial widely used in medicine and high-tech devices, e.g. MEMS and NEMS. In this work, we report an experimental investigation on femtosecond laser processing of PDMS-elastomer with near infrared (NIR), visible (VIS) and ultraviolet (UV) pulses. High definition trenches are produced by varying processing parameters as laser wavelength, pulse duration, fluence, scanning speed and overlap of the subsequent pulses. The sample surface morphology and chemical composition are investigated by Laser Microscopy, SEM and Raman spectroscopy, addressing the effects of the various processing parameters through comparison with the native materials characteristics. For all the laser pulse wavelengths used, the produced tracks are successfully metalized with Ni via electro-less plating method. We observe a negligible influence of the time interval elapsed between laser treatment and metallization process. Our experimental findings suggest promising perspectives of femtosecond laser pulses in micro- and nano-fabrication of hi-tech PDMS devices.

  6. The morphology of corneal cap and its relation to refractive outcomes in femtosecond laser small incision lenticule extraction (SMILE with anterior segment optical coherence tomography observation.

    Directory of Open Access Journals (Sweden)

    Jing Zhao

    Full Text Available PURPOSE: To investigate the morphology of corneal caps in femtosecond laser small incision lenticule extraction (SMILE and its relation to the refractive outcomes. METHODS: A prospective study of fifty-four corneal caps created with VisuMax femtosecond laser were examined using an Fourier-domain optical coherence tomography at 1 day, 1 week, 1 month and 6 months after SMILE. The cap thickness at nine points on each of the four meridians (0°, 45°, 90°, 135° and the diameter were measured. Cap morphology, changes over time and its correlation with refractive outcomes were assessed. RESULTS: The mean achieved central cap thickness were (108.74±5.06 µm at 6 months and (107.32±4.81 µm at 1 month postoperatively, significantly thinner than that at 1 day (110.81±7.95 µm and 1 week (109.58±7.48 µm (P<0.05. The mean diameter on 0° meridian was (7.61±0.07 mm, significantly larger than that on 90° meridian (7.57±0.06 mm (P = 0.001. Cap morphology showed good regularity, except that the differences of points in two pairs were significant at 1 day postoperatively. The uniformity was consistent over time and the central cap thickness was thinner than those in the paracentral and peripheral areas. The refractive outcomes stabilized within 1 month. Uncorrected distance visual acuity (UDVA was correlated to the central cap thickness at 1 day and 1 week (both rs  = 0.33, p<0.05. The uniformity index was correlated with UDVA (rs  = 0.34, p<0.05 and corrected distance visual acuity (rs  = 0.32, p<0.05 at 1 week postoperatively. CONCLUSIONS: Corneal caps of SMILE are predictable with good reproducibility, regularity and uniformity. Cap morphology might have a mild effect on refractive outcomes in the early stage. Further study should focus on the impact on the visual quality.

  7. Laser-assisted direct joining of AISI304 stainless steel with polycarbonate sheets: Thermal analysis, mechanical characterization, and bonds morphology

    Science.gov (United States)

    Lambiase, F.; Genna, S.

    2017-02-01

    Laser-Assisted Metal and Plastic bonding (LAMP) of AISI304 sheets with polycarbonate sheets is investigated in this work. The process was performed by means of a high power diode laser with a maximum power of 200 W. The study introduces an integrated experimental approach aimed at understanding how the main process conditions (laser power and scanning speed) influence the direct-bonds quality, dimensions and presence of defects. To this end, the bonds dimension, shear strength, formation and dimension of bubbles in the bonded region were related to the temperature measurements and process parameters. According to the achieved results, the processing window that enables a good adhesion of the two materials is relatively small; this is due the activation of the adhesion phenomena that require overcoming an energy threshold. However, excessive energy levels reduce the bonds strength due to the increase in defects (bubbles) dimension that may combine (coalescence) leading to the formation of a central tunnel where the two substrates are completely detached.

  8. The Structural and Morphology of (La0.6Sr0.4MnO3 Thin Films Prepared by Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Yang Hai Bin

    2016-01-01

    Full Text Available (La0.7Sr0.3MnO3 (LSMO thin films were prepared on Si (100 substrate by pulsed laser deposition (PLD. Both structure and surface morphology of the films were investigated by X-ray diffraction (XRD and atomic force microscopy (AFM. Furthermore, the chemical states and chemical composition of the films were determined by X-ray photoelectron spectroscopy (XPS near the surface. The results indicate that the films grown on Si (100 substrates have a single pseudo cubic perovskite phase structure with a high (100 orientation. The XPS results show that La, Sr and Mn exist mainly in the forms of perovskite structure and a SrO layer was found on outermost surface.

  9. Ion beam induced chemical and morphological changes in TiO{sub 2} films deposited on Si(1 1 1) surface by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mohanta, R.R. [Department of Chemistry, Krupajal Engineering College, Bhubaneswar 751002 (India); Medicherla, V.R.R., E-mail: mvramarao1@gmail.com [Department of Physics, Institute of Technical Education and Research, Siksha ‘O’ Anusandhan University, Bhubaneswar 751030 (India); Mohanta, K.L. [Department of Physics, Institute of Technical Education and Research, Siksha ‘O’ Anusandhan University, Bhubaneswar 751030 (India); Nayak, Nimai C. [Department of Chemistry, Institute of Technical Education and Research, Siksha ‘O’ Anusandhan University, Bhubaneswar 751030 (India); Majumder, S.; Solanki, V.; Varma, Shikha [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Bapna, Komal; Phase, D.M.; Sathe, V. [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India)

    2015-01-15

    Highlights: • Pulsed laser deposition of TiO{sub 2} films on Si(1 1 1) surface. • XPS and AFM study of TiO{sub 2} surface. • Ion beam treatment induced morphology. • Chemical reduction of TiO{sub 2} on the surface. • A-ray induced Auger transition of Ti LMM. - Abstract: We have investigated TiO{sub 2} films prepared by pulsed laser deposition method on Si(1 1 1) surface using X-ray diffraction (XRD), Raman Spectroscopy, X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and ion beam sputtering techniques. Our XRD data along with Raman indicated that the deposited TiO{sub 2} is in anatase phase. The binding energy position of Ti 2p also supports the anatase phase formation. AFM topography of as deposited film indicates the formation of non uniform TiO{sub 2} growth with the formation of voids on Si(1 1 1) substrate. After sputtering with argon ion beam, surface erosion occurs and voids have disappeared. The Ti 2p core level of sputtered TiO{sub 2} exhibits the formation of Ti{sub 2}O{sub 3}, TiO and pure Ti on the surface. High binding energy shoulder of O 1s peak becomes sharp after sputtering. Ti LMM Auger peaks become broader after sputtering but no shift in kinetic energy is observed.

  10. Effects of low level laser in the morphology of the skeletal muscle fiber during compensatory hypertrophy in plantar muscle of rats

    Science.gov (United States)

    Terena, Stella Maris Lins; Fernandes, Kristianne Porta Santos; Kalil, Sandra; Alves, Agnelo Neves; Mesquita Ferrari, Raquel Agnelli

    2015-06-01

    The hypertrophy is known as an increase the cross-sectional area of the muscle as a result of a muscular work against an overload, and it is compensatory because the overload is induced by functional elimination of synergistic muscles. The importance of study the compensatory hypertrophy is understand how this process can be influenced by the irradiation with regard to the weight and muscle cross-sectional area, to assist in the rehabilitation process and the effectiveness functional return. The aim was evaluate the effects of low-level laser irradiation on morphological aspects of muscle tissue, comparing the weight and cross-sectional area in rat skeletal muscle. Wistar rats were divided into three groups: control, hypertrophy group without irradiation (right plantar muscle) and hypertrophy group and irradiation (left plantar muscle), both analyzed after 7 and 14 days. The irradiation was performed daily immediately after the surgery. The parameters were: λ = 780nm, beam spot of 0.04 cm2, output power of 40mW, power density of 1W/cm2, energy density of 10J / cm2 and 10s exposure time with a total energy of 3.2 J. The results revealed that low level laser irradiation an increase the weight of the plantaris muscle after 7 and 14 days with a difference of 7.06% and 11.51% respectively. In conclusion, low level laser irradiation has an effect on compensatory hypertrophy to produce increased muscle weight and promoted an increase in cross-sectional area of muscle fibers in the compensatory hypertrophy model after 14 days with parameters cited above.

  11. Aluminum film microdeposition at 775 nm by femtosecond laser-induced forward transfer

    Institute of Scientific and Technical Information of China (English)

    Li Yang; Chingyue Wang; Xiaochang Ni; Yinzhong Wu; Wei Jia; Lu Chai

    2007-01-01

    Micro-deposition of an aluminum film of 500-nm thickness on a quartz substrate was demonstrated by laserinduced forward transfer (LIFT) using a femtosecond laser pulse. With the help of atomic force microscopy (AFM) and scanning electron microscopy (SEM), the dependence of the morphology of deposited aluminum film on the irradiated laser pulse energy was investigated. As the laser fluence was slightly above the threshold fluence, the higher pressure of plasma for the thicker film made the free surface of solid phase burst out, which resulted in that not only the solid material was sputtered but also the deposited film in the liquid state was made irregularly.

  12. Morphologies, microstructures, and mechanical properties of samples produced using laser metal deposition with 316 L stainless steel wire

    Science.gov (United States)

    Xu, Xiang; Mi, Gaoyang; Luo, Yuanqing; Jiang, Ping; Shao, Xinyu; Wang, Chunming

    2017-07-01

    Laser metal deposition (LMD) with a filler has been demonstrated to be an effective method for additive manufacturing because of its high material deposition efficiency, improved surface quality, reduced material wastage, and cleaner process environment without metal dust pollution. In this study, single beads and samples with ten layers were successfully deposited on a 316 L stainless steel surface under optimized conditions using a 4000 W continuous wave fibre laser and an arc welding machine. The results showed that satisfactory layered samples with a large deposition height and smooth side surface could be achieved under appropriate parameters. The uniform structures had fine cellular and network austenite grains with good metallurgical bonding between layers, showing an austenite solidification mode. Precipitated ferrite at the grain boundaries showed a subgrain structure with fine uniform grain size. A higher microhardness (205-226 HV) was detected in the middle of the deposition area, while the tensile strength of the 50 layer sample reached 669 MPa. In addition, ductile fracturing was proven by the emergence of obvious dimples at the fracture surface.

  13. Characterization of some biological specimens using TEM and SEM

    Science.gov (United States)

    Ghosh, Nabarun; Smith, Don W.

    2009-05-01

    The advent of novel techniques using the Transmission and Scanning Electron Microscopes improved observation on various biological specimens to characterize them. We studied some biological specimens using Transmission and Scanning Electron Microscopes. We followed negative staining technique with Phosphotungstic acid using bacterial culture of Bacillus subtilis. Negative staining is very convenient technique to view the structural morphology of different samples including bacteria, phage viruses and filaments in a cell. We could observe the bacterial cell wall and flagellum very well when trapped the negative stained biofilm from bacterial culture on a TEM grid. We cut ultra thin sections from the fixed root tips of Pisum sativum (Garden pea). Root tips were pre fixed with osmium tetroxide and post fixed with uranium acetate and placed in the BEEM capsule for block making. The ultrathin sections on the grid under TEM showed the granular chromatin in the nucleus. The protein bodies and large vacuoles with the storage materials were conspicuous. We followed fixation, critical point drying and sputter coating with gold to view the tissues with SEM after placing on stubs. SEM view of the leaf surface of a dangerous weed Tragia hispida showed the surface trichomes. These trichomes when break on touching releases poisonous content causing skin irritation. The cultured tissue from in vitro culture of Albizia lebbeck, a tree revealed the regenerative structures including leaf buds and stomata on the tissue surface. SEM and TEM allow investigating the minute details characteristic morphological features that can be used for classroom teaching.

  14. Influence of a pulsed CO2 laser operating at 9.4 μm on the surface morphology, reflectivity, and acid resistance of dental enamel below the threshold for melting

    Science.gov (United States)

    Kim, Jin Wan; Lee, Raymond; Chan, Kenneth H.; Jew, Jamison M.; Fried, Daniel

    2017-02-01

    Below the threshold for laser ablation, the mineral phase of enamel is converted into a purer phase hydroxyapatite with increased acid resistance. Studies suggest the possibility of achieving the conversion without visible surface alteration. In this study, changes in the surface morphology, reflectivity, and acid resistance were monitored with varying irradiation intensity. Bovine enamel specimens were irradiated using a CO2 laser operating at 9.4 μm with a Gaussian spatial beam profile-1.6 to 3.1 mm in diameter. After laser treatment, samples were subjected to demineralization to simulate the acidic intraoral conditions of dental decay. The resulting demineralization and erosion were assessed using polarization-sensitive optical coherence tomography, three-dimensional digital microscopy, and polarized light microscopy. Distinct changes in the surface morphology and the degree of inhibition were found within the laser-treated area in accordance with the laser intensity profile. Subtle visual changes were noted below the melting point for enamel that appear to correspond to thresholds for denaturation of the organic phase and thermal decomposition of the mineral phase. There was significant protection from laser irradiation in areas in which the reflectivity was not increased significantly, suggesting that aesthetically sensitive areas of the tooth can be treated for caries prevention.

  15. Segmented Foil SEM Grids at Fermilab

    CERN Document Server

    Kopp, Sacha E; Childress, Sam; Ford, R; Harris, Debbie; Indurthy, Dharmaraj; Kendziora, Cary; Moore, Craig D; Pavlovich, Zarko; Proga, Marek; Tassotto, Gianni; Zwaska, Robert M

    2005-01-01

    We present recent beam data from a new design of a profile monitor for proton beams at Fermilab. The monitors, consisting of grids of segmented Ti foils 5micrometers thick, are secondary-electron emission monitors (SEM's). We review data on the device's precision on beam centroid position, beam width, and on beam loss associated with the SEM material placed in the beam.

  16. Laser cleaning of pulsed laser deposited rhodium films for fusion diagnostic mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Uccello, A., E-mail: andrea.uccello@mail.polimi.it [Dipartimento di Energia, Politecnico di Milano, Milan (Italy); Maffini, A., E-mail: alessandro.maffini@mail.polimi.it [Dipartimento di Energia, Politecnico di Milano, Milan (Italy); Dellasega, D., E-mail: david.dellasega@polimi.it [Dipartimento di Energia, Politecnico di Milano, Milan (Italy); Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, Milan (Italy); Passoni, M., E-mail: matteo.passoni@polimi.it [Dipartimento di Energia, Politecnico di Milano, Milan (Italy); Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, Milan (Italy)

    2013-10-15

    Highlights: ► Pulsed laser deposition is exploited to produce Rh films for first mirrors. ► Pulsed laser deposition is exploited to produce tokamak-like C contaminants. ► Rh laser damage threshold has been evaluated for infrared pulses. ► Laser cleaning of C contaminated Rh films gives promising results. -- Abstract: In this paper an experimental investigation on the laser cleaning process of rhodium films, potentially candidates to be used as tokamak first mirrors (FMs), from redeposited carbon contaminants is presented. A relevant issue that lowers mirror's performance during tokamak operations is the redeposition of sputtered material from the first wall on their surface. Among all the possible techniques, laser cleaning, in which a train of laser pulses is launched to the surface that has to be treated, is a method to potentially mitigate this problem. The same laser system (Q-switched Nd:YAG laser with a fundamental wavelength of 1064-nm and 7-ns pulses) has been employed with three aims: (i) production by pulsed laser deposition (PLD) of Rh film mirrors, (ii) production by PLD of C deposits with controlled morphology, and (iii) investigation of the laser cleaning method onto C contaminated Rh samples. The evaluation of Rh films laser damage threshold, as a function of fluence and number of pulses, is discussed. Then, the C/Rh films have been cleaned by the laser beam. The exposed zones have been characterized by visual inspection and scanning electron microscopy (SEM), showing promising results.

  17. Morphology and deflection properties of bat wing sensory hairs: scanning electron microscopy, laser scanning vibrometry, and mechanics model.

    Science.gov (United States)

    Sterbing-D'Angelo, S J; Liu, H; Yu, M; Moss, C F

    2016-08-22

    Bat wings are highly adaptive airfoils that enable demanding flight maneuvers, which are performed with astonishing robustness under turbulent conditions, and stability at slow flight velocities. The bat wing is sparsely covered with microscopically small, sensory hairs that are associated with tactile receptors. In a previous study we demonstrated that bat wing hairs are involved in sensing airflow for improved flight maneuverability. Here, we report physical measurements of these hairs and their distribution on the wing surface of the big brown bat, Eptesicus fuscus, based on scanning electron microscopy analyses. The wing hairs are strongly tapered, and are found on both the dorsal and ventral wing surfaces. Laser scanning vibrometry tests of 43 hairs from twelve locations across the wing of the big brown bat revealed that their natural frequencies inversely correlate with length and range from 3.7 to 84.5 kHz. Young's modulus of the average wing hair was calculated at 4.4 GPa, which is comparable with rat whiskers or arthropod airflow-sensing hairs.

  18. Assessment of the Optic Disc Morphology Using Spectral-Domain Optical Coherence Tomography and Scanning Laser Ophthalmoscopy

    Directory of Open Access Journals (Sweden)

    Pilar Calvo

    2014-01-01

    Full Text Available Objective. To compare the equivalent optic nerve head (OHN parameters obtained with confocal scanning laser ophthalmoscopy (HRT3 and spectral-domain optical coherence tomography (OCT in healthy and glaucoma patients. Methods. One hundred and eighty-two consecutive healthy subjects and 156 patients with open-angle glaucoma were divided into 2 groups according to intraocular pressure and visual field outcomes. All participants underwent imaging of the ONH with the HRT3 and the Cirrus OCT. The ONH parameters and the receiver operating characteristic (ROC curves were compared between both groups. Results. Mean age did not differ between the normal and glaucoma groups (59.55 ± 9.7 years and 61.05 ± 9.4 years, resp.; P=0.15. Rim area, average cup-to-disc (C/D ratio, vertical C/D ratio, and cup volume were different between both instruments (P<0.001. All equivalent ONH parameters, except disc area, were different between both groups (P<0.001. The best areas under the ROC curve were observed for vertical C/D ratio (0.980 for OCT and 0.942 for HRT3; P=0.11. Sensitivities at 95% fixed-specificities of OCT parameters were higher than those of HRT3. Conclusions. Equivalent ONH parameters of Cirrus OCT and HRT3 are different and cannot be used interchangeably. ONH parameters measured with OCT yielded a slightly better diagnostic performance.

  19. UV solid state laser ablation of intraocular lenses

    Science.gov (United States)

    Apostolopoulos, A.; Lagiou, D. P.; Evangelatos, Ch.; Spyratou, E.; Bacharis, C.; Makropoulou, M.; Serafetinides, A. A.

    2013-06-01

    Commercially available intraocular lenses (IOLs) are manufactured from silicone and acrylic, both rigid (e.g. PMMA) and foldable (hydrophobic or hydrophilic acrylic biomaterials), behaving different mechanical and optical properties. Recently, the use of apodizing technology to design new diffractive-refractive multifocals improved the refractive outcome of these intraocular lenses, providing good distant and near vision. There is also a major ongoing effort to refine laser refractive surgery to correct other defects besides conventional refractive errors. Using phakic IOLs to treat high myopia potentially provides better predictability and optical quality than corneal-based refractive surgery. The aim of this work was to investigate the effect of laser ablation on IOL surface shaping, by drilling circular arrays of holes, with a homemade motorized rotation stage, and scattered holes on the polymer surface. In material science, the most popular lasers used for polymer machining are the UV lasers, and, therefore, we tried in this work the 3rd and the 5th harmonic of a Q-switched Nd:YAG laser (λ=355 nm and λ=213 nm respectively). The morphology of the ablated IOL surface was examined with a scanning electron microscope (SEM, Fei - Innova Nanoscope) at various laser parameters. Quantitative measurements were performed with a contact profilometer (Dektak-150), in which a mechanical stylus scanned across the surface of gold-coated IOLs (after SEM imaging) to measure variations in surface height and, finally, the ablation rates were also mathematically simulated for depicting the possible laser ablation mechanism(s). The experimental results and the theoretical modelling of UV laser interaction with polymeric IOLs are discussed in relation with the physical (optical, mechanical and thermal) properties of the material, in addition to laser radiation parameters (laser energy fluence, number of pulses). The qualitative aspects of laser ablation at λ=213 nm reveal a

  20. Biomass fly ash in concrete: SEM, EDX and ESEM analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shuangzhen Wang; Larry Baxter; Fernando Fonseca [Brigham Young University, Provo, UT (USA). Department of Chemical Engineering

    2008-03-15

    This document summarizes microscopy study of concrete prepared from cement and fly ash (25% fly ash and 75% cement by weight), which covers coal fly ash and biomass fly ash. All the fly ash concrete has the statistical equal strength from one day to one year after mix. Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX) and environmental scanning electron microscopy (ESEM) analysis show that both coal and biomass fly ash particles undergo significant changes of morphology and chemical compositions in concrete due to pozzolanic reaction, although biomass fly ash differs substantially from coal fly ash in its fuel resources. 8 refs., 17 figs., 1 tab.

  1. Polymer pixel enhancement by laser-induced forward transfer for sensor applications

    Science.gov (United States)

    Dinca, V.; Palla-Papavlu, A.; Dinescu, M.; Shaw Stewart, J.; Lippert, T. K.; di Pietrantonio, F.; Cannata, D.; Benetti, M.; Verona, E.

    2010-11-01

    This paper presents polymer pixel printing for applications in chemoselective sensors where nanosecond laser direct transfer methods, with a triazene polymer (TP) acting as a Dynamic Release Layer (DRL), are used. A systematic study of laser fluence, donor film morphology and both single- and multiple-pixel deposition were optimized with the final goal to obtain continuous pixels of sensitive polymers, polyethylenimine (PEI) and polyisobutylene (PIB), on SAW surfaces. Morphology characterization after the laser transfer has been performed by Optical Microscopy and Scanning Electron Microscopy (SEM). The responses of the coated transducers were measured after deposition with different laser fluences and it was found that a fluence under 625 mJ/cm2 was required in order to prevent damage of the interdigital transducers (IDT) of the sensor devices. The sensitivity of the polymer coated devices to acetone concentrations gives an indication that LIFT can be used for printing sensitive polymer pixels onto transducer devices.

  2. Influence of argon ambience on the structural, morphological and optical properties of pulsed laser ablated zinc sulfide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chalana, S.R.; Vinodkumar, R.; Navas, I. [Department of Optoelectronics, University of Kerala, Kariavattom, Thiruvananthapuram 695581, Kerala (India); Ganesan, V. [UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore 452 017 (India); Mahadevan Pillai, V.P., E-mail: vpmpillai9@gmail.com [Department of Optoelectronics, University of Kerala, Kariavattom, Thiruvananthapuram 695581, Kerala (India)

    2012-04-15

    Nanostructured zinc suplhide thin films are successfully deposited on quartz substrates using pulsed laser deposition (PLD) under different argon pressures (0, 5, 10, 15 and 20 Pa). The influence of argon ambience on the microstructural, optical and luminescence properties of zinc sulfide (ZnS) thin films is systematically investigated. The GIXRD data suggests rhombohedral structure for ZnS films prepared under different argon ambience. Self-assembly of grains into well-defined patterns along the y direction is observed in the AFM image of the film deposited under argon pressure 20 Pa. All the films show a blue shift in optical band gap. This can be due to the quantum confinement effect and less widening of conduction and valence band for the films with less thickness and smaller grain size. The PL spectra of the different films are recorded at excitation wavelengths 250 nm and 325 nm and the spectra are interpreted. The PL spectra of the films recorded at excitation wavelength 325 nm show intense yellow emission. The film deposited under an argon pressure of 15 Pa shows the highest PL intensity for excitation wavelength 325 nm. For the PL spectra (excitation at 250 nm), the highest PL intensity is observed for the film prepared under argon free ambience. In our study, 15 Pa is the optimum argon pressure for better crystallinity and intense yellow emission when excited at 325 nm. - Highlights: Black-Right-Pointing-Pointer All the films prepared under argon ambience show the presence of rhombohedral phase. Black-Right-Pointing-Pointer All the films show a blue shift in optical band gap. Black-Right-Pointing-Pointer Film deposited at Ar pressure 20 Pa shows a self-assembly of grain in regular patterns. Black-Right-Pointing-Pointer PL spectra of the films for excitation wavelength of 325 nm show an intense yellow emission.

  3. Changes in Anterior Segment Morphology of Iris Bombe before and after Laser Peripheral Iridotomy in Patients with Uveitic Secondary Glaucoma

    Directory of Open Access Journals (Sweden)

    Wakako Ikegawa

    2016-01-01

    Full Text Available Purpose. To quantify changes in anterior segment (AS parameters after laser peripheral iridotomy (LPI using AS-optical coherence tomography (OCT of iris bombe. Method. AS images of eight eyes were captured before and after iris bombe and more than 2 weeks after LPI (post-LPI using AS-OCT. We compared the following AS parameters: anterior chamber depth (ACD, anterior chamber volume (ACV, iris curvature (IC, iris thickness at 500 μm from the scleral spur (IT-1 in the middle between the iris root and pupillary margin (IT-2 and 500 μm from the pupillary margin (IT-3 to the anterior chamber angle (ACA (angle opening distance [AOD750], and trabecular iris space area. Results. Mean IT-1 and IT-3, but not IT-2, were lower after iris bombe (IT-1, P=0.001; IT-2, P=0.081; and IT-3, P=0.001. There were no significant differences between ACD at pre-LPI and before iris bombe (P=0.096. The mean ACV and AOD750 of iris bombe increased at post-LPI (ACV, P<0.01, and AOD750, P<0.05. The mean IT-1, IT-2, and IT-3 increased at post-LPI (all, P≤0.01. IC decreased at post-LPI (P<0.001, and ACD at post-LPI did not change. Conclusions. The iris extends and becomes thinner during iris bombe. LPI during bombe decreases the IC and increases the ACV and ACA.

  4. Comparison of SEM and VPSEM imaging techniques with respect to Streptococcus mutans biofilm topography.

    Science.gov (United States)

    Weber, Kathryn; Delben, Juliana; Bromage, Timothy G; Duarte, Simone

    2014-01-01

    The study compared images of mature Streptococcus mutans biofilms captured at increasing magnification to determine which microscopy method is most acceptable for imaging the biofilm topography and the extracellular polymeric substance (EPS). In vitro S. mutans biofilms were imaged using (1) scanning electron microscopy (SEM), which requires a dehydration process; (2) SEM and ruthenium red (SEM-RR), which has been shown to support the EPS of biofilms during the SEM dehydration; and (3) variable pressure scanning electron microscopy (VPSEM), which does not require the intensive dehydration process of SEM. The dehydration process and high chamber vacuum of both SEM techniques devastated the biofilm EPS, removed supporting structures, and caused cracking on the biofilm surface. The VPSEM offered the most comprehensive representation of the S. mutans biofilm morphology. VPSEM provides similar contrast and focus as the SEM, but the procedure is far less time-consuming, and the use of hazardous chemicals associated with SEM dehydration protocol is avoided with the VPSEM. The inaccurate representations of the biofilm EPS in SEM experimentation is a possible source of inaccurate data and impediments in the study of S. mutans biofilms.

  5. Portable Fiber Laser System and Method to Remove Pits and Cracks on Sensitized Surfaces of Aluminum Alloys

    Science.gov (United States)

    2015-08-01

    2017 0 2) Selection and test of fiber laser 11/1/2017 4/29/2019 0 3) Selection, test, and program a galvano scanner 11/1/2017 4/29/2019 0 4...used to study the morphology of the laser-peened samples. A 3D profiler (New View 8000, Zygo Corporation) was used to measure the 3D profiles of the...profile Scanning probe microscopy (SPM), SEM, and a 3D profiler were used to characterize the surface roughness and profile variations of the laser

  6. AFM, SEM and TEM Studies on Porous Anodic Alumina

    Science.gov (United States)

    Zhu, Yuan Yuan; Ding, Gu Qiao; Ding, Jian Ning; Yuan, Ning Yi

    2010-04-01

    Porous anodic alumina (PAA) has been intensively studied in past decade due to its applications for fabricating nanostructured materials. Since PAA’s pore diameter, thickness and shape vary too much, a systematical study on the methods of morphology characterization is meaningful and essential for its proper development and utilization. In this paper, we present detailed AFM, SEM and TEM studies on PAA and its evolvements with abundant microstructures, and discuss the advantages and disadvantages of each method. The sample preparation, testing skills and morphology analysis are discussed, especially on the differentiation during characterizing complex cross-sections and ultrasmall nanopores. The versatility of PAAs is also demonstrated by the diversity of PAAs’ microstructure.

  7. AFM, SEM and TEM Studies on Porous Anodic Alumina

    Directory of Open Access Journals (Sweden)

    Zhu YuanYuan

    2010-01-01

    Full Text Available Abstract Porous anodic alumina (PAA has been intensively studied in past decade due to its applications for fabricating nanostructured materials. Since PAA’s pore diameter, thickness and shape vary too much, a systematical study on the methods of morphology characterization is meaningful and essential for its proper development and utilization. In this paper, we present detailed AFM, SEM and TEM studies on PAA and its evolvements with abundant microstructures, and discuss the advantages and disadvantages of each method. The sample preparation, testing skills and morphology analysis are discussed, especially on the differentiation during characterizing complex cross-sections and ultrasmall nanopores. The versatility of PAAs is also demonstrated by the diversity of PAAs’ microstructure.

  8. Morphology and Curie temperature engineering in crystalline La{sub 0.7}Sr{sub 0.3}MnO{sub 3} films on Si by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Nori, Rajashree, E-mail: rajsre@ee.iitb.ac.in; Ganguly, U.; Ravi Chandra Raju, N.; Pinto, R.; Ramgopal Rao, V. [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology-Bombay (IIT-B), Mumbai 400076 (India); Kale, S. N. [Department of Applied Physics, Defence Institute of Advanced Technology (DIAT), Pune 411025 (India); Sutar, D. S. [Central Surface Analytical Facility, Indian Institute of Technology-Bombay (IIT-B), Mumbai 400076 (India)

    2014-01-21

    Of all the colossal magnetoresistant manganites, La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO) exhibits magnetic and electronic state transitions above room temperature, and therefore holds immense technological potential in spintronic devices and hybrid heterojunctions. As the first step towards this goal, it needs to be integrated with silicon via a well-defined process that provides morphology and phase control, along with reproducibility. This work demonstrates the development of pulsed laser deposition (PLD) process parameter regimes for dense and columnar morphology LSMO films directly on Si. These regimes are postulated on the foundations of a pressure-distance scaling law and their limits are defined post experimental validation. The laser spot size is seen to play an important role in tandem with the pressure-distance scaling law to provide morphology control during LSMO deposition on lattice-mismatched Si substrate. Additionally, phase stability of the deposited films in these regimes is evaluated through magnetometry measurements and the Curie temperatures obtained are 349 K (for dense morphology) and 355 K (for columnar morphology)—the highest reported for LSMO films on Si so far. X-ray diffraction studies on phase evolution with variation in laser energy density and substrate temperature reveals the emergence of texture. Quantitative limits for all the key PLD process parameters are demonstrated in order enable morphological and structural engineering of LSMO films deposited directly on Si. These results are expected to boost the realization of top-down and bottom-up LSMO device architectures on the Si platform for a variety of applications.

  9. Impact of Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation (RIR-MAPLE) on Morphology and Charge Conduction in Conjugated Polymer and Bulk Heterojunction Thin Films

    Science.gov (United States)

    Stiff-Roberts, Adrienne; McCormick, Ryan; Atewologun, Ayomide

    2014-03-01

    An approach to improve organic photovoltaic efficiency is to increase vertical charge conduction by promoting out-of-plane π- π stacking in conjugated polymers. Resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) features multiple growth parameters that can be varied to achieve a desired organic thin film property. In addition, RIR-MAPLE enables nanoscale domains in blended polymeric films and multi-layer polymeric films regardless of constituent solubility. Thus, RIR-MAPLE deposition is compared to solution-cast films as a possible approach to increase out-of-plane charge transport in polymers and bulk heterojunctions. Two common, solar cell polymers are investigated: P3HT and PCPDTBT. Materials characterization includes grazing-incidence, wide angle x-ray scattering (GIWAXS) for structural information and two techniques to determine hole mobility: organic field effect transistors to measure in-plane mobility and charge extraction by linearly increasing voltage to measure out-of-plane mobility. Initial indications are that the RIR-MAPLE films have a fundamentally different morphology compared to solution-cast films. In the case of P3HT, an enhancement in out-of-plane π- π stacking was observed by GIWAXS in RIR-MAPLE films compared to solution-cast films. A portion of this research was conducted at CNMS at ORNL.

  10. Effects of laser irradiation on Trichophyton rubrum growth and ultrastructure

    Institute of Scientific and Technical Information of China (English)

    XU Zhi-li; XU Jing; ZHUO Feng-lin; WANG Li; XU Wei; XU Ying; ZHANG Xiao-yan; ZHAO Jun-ying

    2012-01-01

    Background Trichophyton rubrum (T.rubrum) is the most common causative agent of dermatophytosis worldwide.In this study,we examined the effect of laser irradiation on the growth and morphology of T.rubrum.Methods Colonies of T.rubrum were isolated (one colony per plate),and randomly assigned to 5 treatment groups:Q-switched 694 nm ruby laser treatment,long-pulsed Nd:YAG 1064 nm laser treatment,intense pulsed light (IPL)treatment,308 nm excimer laser treatment and the blank control group without treatment.Standardized photographs were obtained from grown-up fungal plates prior to treatment.Colonies were then exposed to various wavelengths and fluences of laser light.To compare the growth of colonies,they were re-photographed under identical conditions three and six days post-treatment.To investigate the morphology of T.rubrum,scanning electron microscope (SEM) and transmission electron microscope (TEM) images were obtained from specimens exposed to 24 hours of laser treatment.Results Growth of T.rubrum colonies was significantly inhibited following irradiation by 694 nm Q-switched and 1064nm long-pulsed Nd:YAG lasers.Other treatments exerted little or no effect.Q-switched laser irradiation exerted a stronger growth inhibitory effect than long-pulsed Nd:YAG laser irradiation.Following treatment by the Q-switched ruby laser system,T.rubrum hyphae became shrunken and deflated,and SEM images revealed rough,fractured hyphal surfaces,punctured with small destructive holes.TEM images showed that the hyphae were degenerating,as evidenced by the irregular shape of hyphae,rough and loose cell wall,and obscure cytoplasmic texture.Initially high elect(io)n density structure was visible in the cell; later,low-density structure appeared as a result of cytoplasmic dissolution.In contrast,the blank control group showed no obvious changes in morphology.Conclusion The Q-switched 694 nm ruby laser treatment significantly inhibits the growth and changes the morphology of T.rubrum.

  11. SEM probe of IC radiation sensitivity

    Science.gov (United States)

    Gauthier, M. K.; Stanley, A. G.

    1979-01-01

    Scanning Electron Microscope (SEM) used to irradiate single integrated circuit (IC) subcomponent to test for radiation sensitivity can localize area of IC less than .03 by .03 mm for determination of exact location of radiation sensitive section.

  12. Does Sexually Explicit Media (SEM) Affect Me?

    DEFF Research Database (Denmark)

    Hald, Gert Martin; Træen, Bente; Noor, Syed W

    2015-01-01

    and understanding of one’s sexual orientation.First-person effects refer to self-perceived and self-reported effects of SEM consumptionas experienced by the consumer. In addition, the study examined and provided athorough validation of the psychometric properties of the seven-item PornographyConsumption Effect...... Scale (PCES). The study found that 93% of MSM reported smallto-largepositive effects from their SEM consumption on their sexual knowledge,enjoyment of and interest in sex, attitudes towards sex and understanding of theirsexual orientation. Only 7% reported any negative effects from their SEM......Using a self-selected online sample of 448 Norwegian men who have sex with men(MSM) and a cross-sectional design, the present study investigated first-person effectsof sexually explicit media (SEM) consumption on sexual knowledge, enjoyment of andinterest in sex, attitudes towards sex...

  13. FIB/SEM and SEM/EDS microstructural analysis of metal-ceramic and zirconia-ceramic interfaces.

    Science.gov (United States)

    Massimi, F; Merlati, G; Sebastiani, M; Battaini, P; Menghini, P; Bemporad, E

    2012-01-10

    Recently introduced FIB/SEM analysis in microscopy seems to provide a high-resolution characterization of the samples by 3D (FIB) cross-sectioning and (SEM) high resolution imaging. The aim of this study was to apply the FIB/SEM and SEM/EDS analysis to the interfaces of a metal-ceramic vs. two zirconia-ceramic systems. Plate samples of three different prosthetic systems were prepared in the dental lab following the manufacturers' instructions, where metal-ceramic was the result of a ceramic veneering (porcelain-fused-to-metal) and the two zirconia-ceramic systems were produced by the dedicated CAD-CAM procedures of the zirconia cores (both with final sintering) and then veneered by layered or heat pressed ceramics. In a FIB/SEM equipment (also called DualBeam), a thin layer of platinum (1 μm) was deposited on samples surface crossing the interfaces, in order to protect them during milling. Then, increasingly deeper trenches were milled by a focused ion beam, first using a relatively higher and later using a lower ion current (from 9 nA to 0.28 nA, 30KV). Finally, FEG-SEM (5KV) micrographs (1000-50,000X) were acquired. In a SEM the analysis of the morphology and internal microstructure was performed by 13KV secondary and backscattered electrons signals (in all the samples). The compositional maps were then performed by EDS probe only in the metal-ceramic system (20kV). Despite the presence of many voids in all the ceramic layers, it was possible to identify: (1) the grain structures of the metallic and zirconia substrates, (2) the thin oxide layer at the metal-ceramic interface and its interactions with the first ceramic layer (wash technique), (3) the roughness of the two different zirconia cores and their interactions with the ceramic interface, where the presence of zirconia grains in the ceramic layer was reported in two system possibly due to sandblasting before ceramic firing.

  14. Bacterial morphologies in carbonaceous meteorites and comet dust

    Science.gov (United States)

    Wickramasinghe, Chandra; Wallis, Max K.; Gibson, Carl H.; Wallis, Jamie; Al-Mufti, Shirwan; Miyake, Nori

    2010-09-01

    Three decades ago the first convincing evidence of microbial fossils in carbonaceous chondrites was discovered and reported by Hans Dieter Pflug and his collaborators. In addition to morphology, other data, notably laser mass spectroscopy, confirmed the identification of such structures as putative bacterial fossils. Balloon-borne cryosampling of the stratosphere enables recovery of fragile cometary dust aggregates with their structure and carbonaceous matter largely intact. SEM studies of texture and morphology of particles in the Cardiff collection, together with EDX identifications, show two main types of putative bio-fossils - firstly organic-walled hollow spheres around 10μm across, secondly siliceous diatom skeletons similar to those found in carbonaceous chondrites and terrestrial sedimentary rocks and termed 'acritarchs'. Since carbonaceous chondrites (particularly Type 1 chondrites) are thought to be extinct comets the data reviewed in this article provide strong support for theories of cometary panspermia.

  15. Detection of Coaxial Backscattered Electrons in SEM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    We present a coaxial detection of the backscattered electrons in SEM. The lens-aperture has been used to filter in energy and focus the backscattered electrons. This particular geometry allows us to eliminate the iow energy backscattered electrons and collect the backscattered electrons, which are backscattered close to the incident beam orientation. The main advantage of this geometry is adapted to topographic contrast attenuation and atomic number contrast enhancement. Thus this new SEM is very suitable to analyze the material composition.

  16. Comparison of particle sizes determined with impactor, AFM and SEM

    Science.gov (United States)

    Gwaze, Patience; Annegarn, Harold J.; Huth, Joachim; Helas, Günter

    2007-11-01

    Particles size comparisons were made between conventional aerodynamic and mobility sizing techniques and physical geometric sizes measured by high resolution microscopes. Atmospheric particles were collected during the wet and dry seasons in the Amazonian ecosystems. Individual particles deposited on four stages of the MOUDI (Micro-Orifice Uniform Deposition Impactor) were characterised for particle volumes, projected surface diameters and morphologies with an Atomic Force Microscope (AFM) and a Scanning Electron Microscope (SEM). AFM and SEM size distributions were verified against distributions derived from response functions of individual MOUDI stages as specified by Winklmayr et al. [Winklmayr, W., Wang, H.-C., John, W., 1990. Adaptation of the Twomey algorithm to the inversion of cascade impactor data. Aerosol Science and Technology 13, 322-331.]. Particles indicated inherent discrepancies in sizing techniques. Particle volumes were systematically lower than expected by factors of up to 3.6. Differences were attributed to loss of mass, presumably water adsorbed on particles. Losses were high and could not be accounted for by measured humidity growth factors suggesting significant losses of other volatile compounds as well, particularly on particles that were collected during the wet season. Microscopy results showed that for hygroscopic particles, microscopy sizes depend on the relative humidity history of particles before and after sampling. Changes in relative humidity significantly altered particle morphologies. Depending on when changes occur, such losses will bias not only microscopy particle sizes but also impactor mass distributions and number concentrations derived from collected particles.

  17. Nd:YAG laser irradiation on temporary teeth carious tissue using 12% diamine silver fluoride as a photo-absorber - a morphological study; Estudo comparativo morfologico da acao do laser de Nd:YAG em dentina cariada de dentes deciduos in vitro, condicionados com diamino fluoreto de prata a 12% e carvao mineral

    Energy Technology Data Exchange (ETDEWEB)

    Calmon, Andrea de Avillez

    2001-07-01

    Since Nd:YAG laser radiation was first introduced in Dentistry various photo-absorbers were employed with the intent of improving its efficacy when used on dental carious tissue. The purpose of the present study was to analyze the influence of this radiation using Scanning and Optical microscopy over carious tissue of primary teeth using two photo-absorbers. 15 primary human teeth were used and, in each one, 3 cavity preparations were performed. Specimens were then submitted to an in vitro demineralizing environment during 18 days. Two of the cavities of each specimen were laser irradiated using the Nd:YAG laser with 60 mJ of energy per pulse, 10 Hz and average power of 0,6 W. The 12% diamine silver fluoride or the mineral coal were used as photo-absorbers. The third cavity of the specimens was used as a control and received no laser irradiation. Samples were transversally cut and the section analyzed by SEM and OM. Results showed that the 12% diamine silver fluoride is an efficient photo-absorber and, when used it the Nd:YAG laser, leading to melting and resolidification of the carious tissue. It can be concluded that the 12% diammine silver fluoride presents advantages over the mineral coal as a photo absorber when used in primary teeth as it promotes and improves the efficacy of laser irradiation. This substance also works as a barrier on the carie progression in deeper areas such as the infected and necrotic zones. (author)

  18. Effects of ultraviolet nanosecond laser irradiation on structural modification and optical transmission of single layer graphene

    Science.gov (United States)

    Li, Chunhong; Kang, Xiaoli; Zhu, Qihua; Zheng, Wanguo

    2017-03-01

    Structural modifications and optical transmission change of single layer graphene (SLG) on transparent SiO2 substrate induced by nanosecond 355 nm laser irradiation were systematically studied by scanning electron microscopy (SEM), laser-excited Raman, X-ray photon spectroscopy (XPS) and UV-vis transmission spectra. In this study, to avoid damage to graphene, the selected irradiation fluence was set to be smaller than the laser damage threshold of SLG. Laser-driven formation of nano-dots, carbon clusters and spherical carbon morphologies were clearly presented using SEM magnification images, and the formation mechanism of such structures were discussed. Raman spectra revealed formation of D' peak and the continuously increasing of ID/IG intensity ratio with the concurrent increase of laser fluence, indicating the increase in amount of structural defects and disordering in SLG. XPS results disclosed that the oxygen content in SLG increases with laser fluence. The formation and relative content increase of Cdbnd O, Csbnd Osbnd C and Osbnd Cdbnd O bonds in SLG induced by laser irradiation were also revealed by XPS. Laser-driven micro-structure modifications of crystalline graphene to nano-crystalline graphene and photo-chemical reactions between graphene and O2 and H2O in air environment were suggested to be responsible for the Raman and XPS revealed modifications in SLG. It is worthy to point out that the above mentioned structural modifications only caused a slight decrease (graphene aiming at modifying its structure and thus taiorling its properties.

  19. Influence of Er,Cr:YSGG laser treatment on microtensile bond strength of adhesives to enamel.

    Science.gov (United States)

    Cardoso, Marcio Vivan; De Munck, Jan; Coutinho, Eduardo; Ermis, R Banu; Van Landuyt, Kirsten; de Carvalho, Rubens Corte Real; Van Meerbeek, Bart

    2008-01-01

    The current trend towards minimum-intervention dentistry has introduced laser technology as an alternative technique for cavity preparation. This study assessed the null hypothesis that enamel prepared either by Er,Cr:YSGG laser or conventional diamond bur is equally receptive to adhesive procedures. The buccal and lingual surfaces of 35 sound human molars were prepared with Er,Cr:YSGG laser or a medium-grit diamond bur. One etch&rinse (OptiBond FL) and three self-etch adhesives (Adper Prompt L-Pop, Clearfil SE Bond and Clearfil S3 Bond) were applied on laser-irradiated and bur-cut enamel, followed by the application of a 5-6 mm build-up of Z100. The micro-tensile bond strength (microTBS) was determined after 24 hours of storage in water at 37 degrees C. Prepared enamel surfaces and failure patterns were evaluated using a stereomicroscope and a field-emission-gun scanning electron microscope (Feg-SEM). The pTBS to laser-irradiated enamel was significantly lower than to bur-cut enamel (pOptiBond FL. SEM analysis revealed significant morphological alterations of the laser-irradiated enamel surface, such as areas of melted and recrystalized hydroxyapatite and deep extensive micro-cracks. In conclusion, the bonding effectiveness of adhesives to laser-irradiated enamel depends not only on the structural substrate alterations induced by the laser, but also on the characteristics of the adhesive employed.

  20. Effects of femtosecond laser ablation on the surface morphology and microstructure of a bulk TiCuPdZr glass alloy

    Institute of Scientific and Technical Information of China (English)

    WANG Hongshui; LIANG Chunyong; CHEN Xueguang; WANG Lei; YANG Yang; YANG Jianjun; ZHU Shengli; LI Changyi

    2009-01-01

    The effects of femtosecond laser ablation on the surface characteristics and microstructure of a bulk TiCuPdZr glass alloy were investigated. The heat influence zone of femtosecond laser ablated with a laser energy of 100 μJ exhibits a ripple-like feather, while a porous structure appears on the surface of the specimen ablated by a 200 μJ femtosecond laser. The contents of Ti, Zr, and Pd on the ablated surface decrease and that of Cu increases with increasing laser energy. The crystallization process occurs on the glass alloy specimens during femtosecond laser ablation, and the crystallinity of a 100 μJ femtosecond laser-ablated specimen is greater than that of a 200 μJ femtosecond laser-ablated one.

  1. Laser Treatment of HVOF Coating: Modeling and Measurement of Residual Stress in Coating

    Science.gov (United States)

    Arif, A. F. M.; Yilbas, B. S.

    2008-10-01

    High-velocity oxy-fuel (HVOF) coating of diamalloy 1005 (similar to Inconel 625 alloy) onto the Ti-6Al-4V alloy is considered and laser-controlled melting of the coating is examined. The residual stress developed after the laser treatment process is modeled using the finite element method (FEM). The experiment is conducted to melt the coating using a laser beam. The residual stress measurement in the coating after the laser treatment process is realized using the XRD technique. The morphological and metallurgical changes in the coating are examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). It is found that the residual stress reduces at the coating-base material interface and the residual stress predicted agrees with the XRD measurements. A compact and crack-free coating is resulted after the laser treatment process.

  2. Combined effects of electromagnetic field and low-level laser increase proliferation and alter the morphology of human adipose tissue-derived mesenchymal stem cells.

    Science.gov (United States)

    Nurković, Jasmin; Zaletel, Ivan; Nurković, Selmina; Hajrović, Šefćet; Mustafić, Fahrudin; Isma, Jovan; Škevin, Aleksandra Jurišić; Grbović, Vesna; Filipović, Milica Kovačević; Dolićanin, Zana

    2017-01-01

    In recent years, electromagnetic field (EMF) and low-level laser (LLL) have been found to affect various biological processes, the growth and proliferation of cells, and especially that of stem cells. The aim of this study was to investigate the effects of EMF and LLL on proliferation of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) and thus to examine the impact of these therapeutic physical modalities on stem cell engraftment. hAT-MSCs were isolated from subcutaneous adipose tissue of six persons ranging in age from 21 to 56 years. EMF was applied for a period of 7 days, once a day for 30 min, via a magnetic cushion surface at a frequency of 50 Hz and an intensity of 3 mT. LLL was applied also for 7 days, once a day for 5 min, at radiation energies of 3 J/cm(2), with a wavelength of 808 nm, power output of 200 mW, and power density of 0.2 W/cm(2). Nonexposed cells (control) were cultivated under the same culture conditions. Seven days after treatment, the cells were examined for cell viability, proliferation, and morphology. We found that after 7 days, the number of EMF-treated hAT-MSCs was significantly higher than the number of the untreated cells, LLL-treated hAT-MSCs were more numerous than EMF-treated cells, and hAT-MSCs that were treated with the combination of EMF and LLL were the most numerous. EMF and/or LLL treatment did not significantly affect hAT-MSC viability by itself. Changes in cell morphology were also observed, in terms of an increase in cell surface area and fractal dimension in hAT-MSCs treated with EMF and the combination of EMF and LLL. In conclusion, EMF and/or LLL treatment accelerated the proliferation of hAT-MSCs without compromising their viability, and therefore, they may be used in stem cell tissue engineering.

  3. Partial Least Squares Strukturgleichungsmodellierung (PLS-SEM)

    DEFF Research Database (Denmark)

    Hair, Joe F.; Hult, G. Thomas M.; Ringle, Christian M.

    (PLS-SEM) hat sich in der wirtschafts- und sozialwissenschaftlichen Forschung als geeignetes Verfahren zur Schätzung von Kausalmodellen behauptet. Dank der Anwenderfreundlichkeit des Verfahrens und der vorhandenen Software ist es inzwischen auch in der Praxis etabliert. Dieses Buch liefert eine...... anwendungsorientierte Einführung in die PLS-SEM. Der Fokus liegt auf den Grundlagen des Verfahrens und deren praktischer Umsetzung mit Hilfe der SmartPLS-Software. Das Konzept des Buches setzt dabei auf einfache Erläuterungen statistischer Ansätze und die anschauliche Darstellung zahlreicher Anwendungsbeispiele anhand...... einer einheitlichen Fallstudie. Viele Grafiken, Tabellen und Illustrationen erleichtern das Verständnis der PLS-SEM. Zudem werden dem Leser herunterladbare Datensätze, Aufgaben und weitere Fachartikel zur Vertiefung angeboten. Damit eignet sich das Buch hervorragend für Studierende, Forscher und...

  4. FIB-SEM tomography in biology.

    Science.gov (United States)

    Kizilyaprak, Caroline; Bittermann, Anne Greet; Daraspe, Jean; Humbel, Bruno M

    2014-01-01

    Three-dimensional information is much easier to understand than a set of two-dimensional images. Therefore a layman is thrilled by the pseudo-3D image taken in a scanning electron microscope (SEM) while, when seeing a transmission electron micrograph, his imagination is challenged. First approaches to gain insight in the third dimension were to make serial microtome sections of a region of interest (ROI) and then building a model of the object. Serial microtome sectioning is a tedious and skill-demanding work and therefore seldom done. In the last two decades with the increase of computer power, sophisticated display options, and the development of new instruments, an SEM with a built-in microtome as well as a focused ion beam scanning electron microscope (FIB-SEM), serial sectioning, and 3D analysis has become far easier and faster.Due to the relief like topology of the microtome trimmed block face of resin-embedded tissue, the ROI can be searched in the secondary electron mode, and at the selected spot, the ROI is prepared with the ion beam for 3D analysis. For FIB-SEM tomography, a thin slice is removed with the ion beam and the newly exposed face is imaged with the electron beam, usually by recording the backscattered electrons. The process, also called "slice and view," is repeated until the desired volume is imaged.As FIB-SEM allows 3D imaging of biological fine structure at high resolution of only small volumes, it is crucial to perform slice and view at carefully selected spots. Finding the region of interest is therefore a prerequisite for meaningful imaging. Thin layer plastification of biofilms offers direct access to the original sample surface and allows the selection of an ROI for site-specific FIB-SEM tomography just by its pronounced topographic features.

  5. Fabrication and morphology of (Hg,Re)-1212 thin films on LaAlO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Su, J.H.; Sastry, P.V.P.S.S.; Schwartz, J

    2003-04-15

    Superconducting (Hg,Re)Ba{sub 2}CaCu{sub 2}O{sub y} ((Hg,Re)-1212) thin films have been prepared on single crystal substrates of LaAlO{sub 3} by reacting laser deposited ReBaCaCuO precursor films with CaHgO{sub 2} in sealed quartz tubes. The effects of the deposition parameters such as laser fluence and substrate temperature, on surface morphology and microstructure were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM). AFM observations revealed that a granular structure was seen in the precursor films deposited at lower energy (less than 200 mJ) and disappeared at higher energy (250 mJ). SEM investigation on final reacted films showed that the precursor films deposited at 250 deg. C resulted in a well-connected and uniformly dense microstructure, whereas the films deposited at lower or higher temperatures were porous and non-uniform.

  6. SEM-668-G2(日东科技)

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    SEM-668-G2比SEM-668在视觉技术上更加精湛,采用美国AGILENT(安提伦)LASER 5519A及HP的双重频率技术,加强运动;隹确性。在智能化印刷头上,SEM-668-G2印刷质量更加均匀、稳定,操作界面更加简易、更加人性化。在综合性能上更加卓越,保证实现现代化的生产效率。产品体具性能如下:SEM-668-G2视觉全自动印刷机

  7. Laser surface texturing of tool steel: textured surfaces quality evaluation

    Science.gov (United States)

    Šugár, Peter; Šugárová, Jana; Frnčík, Martin

    2016-05-01

    In this experimental investigation the laser surface texturing of tool steel of type 90MnCrV8 has been conducted. The 5-axis highly dynamic laser precision machining centre Lasertec 80 Shape equipped with the nano-second pulsed ytterbium fibre laser and CNC system Siemens 840 D was used. The planar and spherical surfaces first prepared by turning have been textured. The regular array of spherical and ellipsoidal dimples with a different dimensions and different surface density has been created. Laser surface texturing has been realized under different combinations of process parameters: pulse frequency, pulse energy and laser beam scanning speed. The morphological characterization of ablated surfaces has been performed using scanning electron microscopy (SEM) technique. The results show limited possibility of ns pulse fibre laser application to generate different surface structures for tribological modification of metallic materials. These structures were obtained by varying the processing conditions between surface ablation, to surface remelting. In all cases the areas of molten material and re-cast layers were observed on the bottom and walls of the dimples. Beside the influence of laser beam parameters on the machined surface quality during laser machining of regular hemispherical and elipsoidal dimple texture on parabolic and hemispherical surfaces has been studied.

  8. Surface-enhanced Raman scattering in femtosecond laser-nanostructured Ag substrate

    Energy Technology Data Exchange (ETDEWEB)

    Dai Ye; He Min; Yan Xiaona; Ma Guohong [Department of Physics, Shanghai University, Shanghai 200444 (China); Lu Bo, E-mail: yedai@shu.edu.cn [Instrumental Analysis and Research Center, Shanghai University, Shanghai 200444 (China)

    2011-02-01

    We demonstrate that a surface-enhanced Raman scattering (SERS) substrate could be directly fabricated on the surface of Ag film by femtosecond laser micromachining. According to the morphology observation by SEM, an amount of nanoparticles, nanoprotrusions, and nanospikes were found to form in the ablation region and the density and size distribution of these Ag nanoparticles depended possibly on the incident laser intensity. Additionally, a large area of nanostructured region was produced by fast line scanning, and an enhancement factor of {approx}10{sup 5} was obtained in this region after the sample was soaked in the rhodamine 6G solution for 30 min.

  9. Influence of dc bias on amorphous carbon deposited by pulse laser ablation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Amorphous carbon films were deposited on single-crystalline silicon and K9 glass by pulse laser ablation using different negative substrate bias. Scanning electron microscope (SEM) was used to observe morphology of the surface. Thickness and refractive index of the film deposited on K9 glass were measured by ellipsometry. Micro-hardness of films was measured relatively to single crystal silicon. All films deposited on silicon were analyzed by Raman spectra. All spectra were deconvoluted to three peaks. Line-width ratios varied similarly with bias voltage when the laser energy was kept invariant.

  10. Search Engine Marketing (SEM: Financial & Competitive Advantages of an Effective Hotel SEM Strategy

    Directory of Open Access Journals (Sweden)

    Leora Halpern Lanz

    2015-05-01

    Full Text Available Search Engine Marketing and Optimization (SEO, SEM are keystones of a hotels marketing strategy, in fact research shows that 90% of travelers start their vacation planning with a Google search. Learn five strategies that can enhance a hotels SEO and SEM strategies to boost bookings.

  11. METROLOGICAL PERFORMANCE OF SEM 3D TECHNIQUES

    DEFF Research Database (Denmark)

    Marinello, Francesco; Carmignato, Simone; Savio, Enrico;

    2008-01-01

    This paper addresses the metrological performance of three-dimensional measurements performed with Scanning Electron Microscopes (SEMs) using reconstruction of surface topography through stereo-photogrammetry. Reconstruction is based on the model function introduced by Piazzesi adapted for eucent...... condition are studied, in order to define a strategy to optimise the measurements taking account of the critical factors in SEM 3D reconstruction. Investigations were performed on a novel sample, specifically developed and implemented for the tests.......This paper addresses the metrological performance of three-dimensional measurements performed with Scanning Electron Microscopes (SEMs) using reconstruction of surface topography through stereo-photogrammetry. Reconstruction is based on the model function introduced by Piazzesi adapted...... and the instrument set-up; the second concerns the quality of scanned images and represents the major criticality in the application of SEMs for 3D characterizations. In particular the critical role played by the tilting angle and its relative uncertainty, the magnification and the deviations from the eucentricity...

  12. Building a SEM Analytics Reporting Portfolio

    Science.gov (United States)

    Goff, Jay W.; Williams, Brian G.; Kilgore, Wendy

    2016-01-01

    Effective strategic enrollment management (SEM) efforts require vast amounts of internal and external data to ensure that meaningful reporting and analysis systems can assist managers in decision making. A wide range of information is integral for leading effective and efficient student recruitment and retention programs. This article is designed…

  13. Building a SEM Analytics Reporting Portfolio

    Science.gov (United States)

    Goff, Jay W.; Williams, Brian G.; Kilgore, Wendy

    2016-01-01

    Effective strategic enrollment management (SEM) efforts require vast amounts of internal and external data to ensure that meaningful reporting and analysis systems can assist managers in decision making. A wide range of information is integral for leading effective and efficient student recruitment and retention programs. This article is designed…

  14. Comparing SVARs and SEMs : more shocking stories

    NARCIS (Netherlands)

    Jacobs, Jan; Wallis, Kenneth F.

    2002-01-01

    The structural vector autoregression (SVAR) and simultaneous equation macroeconometric model (SEM) styles of empirical macroeconomic modelling are compared and contrasted, with reference to two models of the UK economy, namely the Cambridge long-run structural VAR model and the COMPACT model.

  15. Nanosecond laser ablation and deposition of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Siew, Wee Ong; Tou, Teck Yong [Multimedia University, Faculty of Engineering, Cyberjaya, Selangor (Malaysia); Yap, Seong Shan; Reenaas, Turid Worren [Norwegian University of Science and Technology, Department of Physics, Trondheim (Norway); Ladam, Cecile; Dahl, Oeystein [SINTEF Materials and Chemistry, Trondheim (Norway)

    2011-09-15

    Nanosecond-pulsed KrF (248 nm, 25 ns) and Nd:YAG (1064 nm, 532 nm, 355 nm, 5 ns) lasers were used to ablate a polycrystalline Si target in a background pressure of <10{sup -4} Pa. Si films were deposited on Si and GaAs substrates at room temperature. The surface morphology of the films was characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Round droplets from 20 nm to 5 {mu}m were detected on the deposited films. Raman Spectroscopy indicated that the micron-sized droplets were crystalline and the films were amorphous. The dependence of the properties of the films on laser wavelengths and fluence is discussed. (orig.)

  16. Selective removal of carious lesion with Er:YAG laser followed by dentin biomodification with chitosan.

    Science.gov (United States)

    Curylofo-Zotti, Fabiana A; Tanta, Gabriela Solano; Zucoloto, Miriane Lucindo; Souza-Gabriel, Aline E; Corona, Silmara A M

    2017-08-01

    The aim of this study was to evaluate the effect of Er:YAG laser for selective removal of carious lesion, followed by biomodification with chitosan gel where the subsurface microhardness, chemical composition, and morphological changes of the residual caries-affected dentin were examined. Artificial dentinal lesions were created by pH-cycling method (14 days) in 104 bovine specimens (5 × 5 mm). Specimens were randomly divided according to the carious removal method: bur (low-speed handpiece) or Er:YAG laser (250 mJ/4 Hz). Specimens were treated with 35% phosphoric acid and were subdivided into two groups according to dentin biomodification: without chitosan (control) and 2.5% chitosan. Forty specimens were restored with an adhesive system and composite resin. Subsurface microhardness tests were performed in sound dentin, caries-affected dentin, residual caries-affected dentin, and after the restoration. The other 64 specimens were subjected to SEM-EDS atomic analysis. Data were statistically analyzed (p carious lesions with Er:YAG laser (p  0.05). SEM analysis showed morphological changes on residual caries-affected dentin (p > 0.05). The selective removal of carious dentin with Er:YAG laser increased microhardness of residual caries-affected dentin, changing its surface morphology and chemical composition. The biomodification with chitosan did not influence the structural and chemical composition of residual caries-affected dentin.

  17. Effect of laser treatment on the attachment and viability of mesenchymal stem cell responses on shape memory NiTi alloy

    Energy Technology Data Exchange (ETDEWEB)

    Chan, C.W., E-mail: c.w.chan@qub.ac.uk [School of Mechanical and Aerospace Engineering, Queen' s University, Belfast, Northern Ireland (United Kingdom); Hussain, I. [School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln, Lincolnshire LN6 7TU (United Kingdom); Waugh, D.G.; Lawrence, J. [Laser Engineering and Manufacturing Research Group, Faculty of Science and Engineering, University of Chester, Parkgate Road, Chester, CH1 4BJ (United Kingdom); Man, H.C. [Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

    2014-09-01

    The objectives of this study were to investigate the effect of laser-induced surface features on the morphology, attachment and viability of mesenchymal stem cells (MSCs) at different periods of time, and to evaluate the biocompatibility of different zones: laser-melted zone (MZ), heat-affected zone (HAZ) and base metal (BM) in laser-treated NiTi alloy. The surface morphology and composition were studied by scanning electron microscope (SEM) and X-ray photoemission spectroscopy (XPS), respectively. The cell morphology was examined by SEM while the cell counting and viability measurements were done by hemocytometer and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The results indicated that the laser-induced surface features, such as surface roughening, presence of anisotropic dendritic pattern and complete surface Ni oxidation were beneficial to improve the biocompatibility of NiTi as evidenced by the highest cell attachment (4 days of culture) and viability (7 days of culture) found in the MZ. The biocompatibility of the MZ was the best, followed by the BM with the HAZ being the worst. The defective and porous oxide layer as well as the coarse grained structure might attribute to the inferior cell attachment (4 days of culture) and viability (7 days of culture) on the HAZ compared with the BM which has similar surface morphology. - Highlights: • Laser-treated surface induces a more spreading cell morphology than the non-treated. • Laser-treated surface shows higher cell attachment and viability than the non-treated. • Laser surface treatment is a feasible method to improve the responses of MSCs. • The improvement is attributed to the surface features induced by laser treatment.

  18. Growth of decagonal quasicrystal phase in laser resolidified Al72Ni12Co16

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An ultra-high temperature gradient directional solidification process produced by a widened laser beam was adopted to achieve the directionally solidified microstructure of the stable decagonal quasicrystal phase in Al72Ni12Co16 alloy. X-ray, SEM, TEM and optical microscopy techniques were used to investigate the microstructures and identify the phase. The directionally solidified decagonal quasicrystal showed the facet morphology and grew in lateral growth mode. The unusual periodic and quasiperiodic atomic structures of the decagonal quasicrystal and the epitaxial growth in the melt pool were considered to be the key factors influencing the growth morphology. The experimental results were consistent with the Toner's theoretical atomistic growth model.

  19. Data Fitting to Study Ablated Hard Dental Tissues by Nanosecond Laser Irradiation.

    Directory of Open Access Journals (Sweden)

    Y Al-Hadeethi

    Full Text Available Laser ablation of dental hard tissues is one of the most important laser applications in dentistry. Many works have reported the interaction of laser radiations with tooth material to optimize laser parameters such as wavelength, energy density, etc. This work has focused on determining the relationship between energy density and ablation thresholds using pulsed, 5 nanosecond, neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O12 (Nd:YAG laser at 1064 nanometer. For enamel and dentin tissues, the ablations have been performed using laser-induced breakdown spectroscopy (LIBS technique. The ablation thresholds and relationship between energy densities and peak areas of calcium lines, which appeared in LIBS, were determined using data fitting. Furthermore, the morphological changes were studied using Scanning Electron Microscope (SEM. Moreover, the chemical stability of the tooth material after ablation has been studied using Energy-Dispersive X-Ray Spectroscopy (EDX. The differences between carbon atomic % of non-irradiated and irradiated samples were tested using statistical t-test. Results revealed that the best fitting between energy densities and peak areas of calcium lines were exponential and linear for enamel and dentin, respectively. In addition, the ablation threshold of Nd:YAG lasers in enamel was higher than that of dentin. The morphology of the surrounded ablated region of enamel showed thermal damages. For enamel, the EDX quantitative analysis showed that the atomic % of carbon increased significantly when laser energy density increased.

  20. Study on the role of laser surface irradiation on damage and decohesion of Al/epoxy joints

    KAUST Repository

    Alfano, Marco

    2012-12-01

    In this work we investigate the effect of laser irradiation on the bond toughness of aluminum/epoxy bonded joints. The evolution of substrate surface morphology and wettability, for various sets of laser process parameters (i.e. laser power, line spacing, scan speed), was investigated by means of Scanning Electron Microscopy (SEM) and contact angle measurements. A proper combination of power, line spacing and scan speed was then selected and adhesive bonded Al/epoxy T-peel joints were prepared and tested. For comparison, similar samples were produced using substrates with classical grit blasting surface treatment. Finally, post-failure SEM analyses of fracture surfaces were performed, and in order to typify the increase in bond toughness of the joints, finite element simulations were carried out using a potential based cohesive zone model of fracture. © 2012 Elsevier Ltd.

  1. Focused ion beam (FIB)/scanning electron microscopy (SEM) in tissue structural research.

    Science.gov (United States)

    Leser, Vladka; Milani, Marziale; Tatti, Francesco; Tkalec, Ziva Pipan; Strus, Jasna; Drobne, Damjana

    2010-10-01

    The focused ion beam (FIB) and scanning electron microscope (SEM) are commonly used in material sciences for imaging and analysis of materials. Over the last decade, the combined FIB/SEM system has proven to be also applicable in the life sciences. We have examined the potential of the focused ion beam/scanning electron microscope system for the investigation of biological tissues of the model organism Porcellio scaber (Crustacea: Isopoda). Tissue from digestive glands was prepared as for conventional SEM or as for transmission electron microscopy (TEM). The samples were transferred into FIB/SEM for FIB milling and an imaging operation. FIB-milled regions were secondary electron imaged, back-scattered electron imaged, or energy dispersive X-ray (EDX) analyzed. Our results demonstrated that FIB/SEM enables simultaneous investigation of sample gross morphology, cell surface characteristics, and subsurface structures. The same FIB-exposed regions were analyzed by EDX to provide basic compositional data. When samples were prepared as for TEM, the information obtained with FIB/SEM is comparable, though at limited magnification, to that obtained from TEM. A combination of imaging, micro-manipulation, and compositional analysis appears of particular interest in the investigation of epithelial tissues, which are subjected to various endogenous and exogenous conditions affecting their structure and function. The FIB/SEM is a promising tool for an overall examination of epithelial tissue under normal, stressed, or pathological conditions.

  2. Laser deposition of sulfonated phthalocyanines for gas sensors

    Energy Technology Data Exchange (ETDEWEB)

    Fitl, Premysl, E-mail: fitlp@vscht.cz [Department of Physics and Measurements, Institute of Chemical Technology Prague, Technicka 5, Prague 6 CZ-166 28 (Czech Republic); Department of Analysis of Functional Materials, Institute of Physics AS CR v.v.i, Na Slovance 1999/2, Prague 8 CZ-182 21 (Czech Republic); Vrnata, Martin; Kopecky, Dusan; Vlcek, Jan; Skodova, Jitka [Department of Physics and Measurements, Institute of Chemical Technology Prague, Technicka 5, Prague 6 CZ-166 28 (Czech Republic); Bulir, Jiri; Novotny, Michal; Pokorny, Petr [Department of Analysis of Functional Materials, Institute of Physics AS CR v.v.i, Na Slovance 1999/2, Prague 8 CZ-182 21 (Czech Republic)

    2014-05-01

    Thin layers of nickel and copper tetrasulfonated phthalocyanines (NiPcTS and CuPcTS) were prepared by Matrix Assisted Pulsed Laser Evaporation method. The depositions were carried out with KrF excimer laser (energy density of laser radiation E{sub L} = 0.1–0.5 J cm{sup −2}) from dimethylsulfoxide matrix. For both materials the ablation threshold E{sub L-th} was determined. The following properties of deposited layers were characterized: (a) chemical composition (FTIR spectra); (b) morphology (SEM and AFM portraits); and (c) impedance of gas sensors based on NiPcTS and CuPcTS layers in the presence of two analytes – hydrogen and ozone. The prepared sensors exhibit response to 1000 ppm of hydrogen and 100 ppb of ozone even at laboratory temperature.

  3. Laser deposition of sulfonated phthalocyanines for gas sensors

    Science.gov (United States)

    Fitl, Premysl; Vrnata, Martin; Kopecky, Dusan; Vlcek, Jan; Skodova, Jitka; Bulir, Jiri; Novotny, Michal; Pokorny, Petr

    2014-05-01

    Thin layers of nickel and copper tetrasulfonated phthalocyanines (NiPcTS and CuPcTS) were prepared by Matrix Assisted Pulsed Laser Evaporation method. The depositions were carried out with KrF excimer laser (energy density of laser radiation EL = 0.1-0.5 J cm-2) from dimethylsulfoxide matrix. For both materials the ablation threshold EL-th was determined. The following properties of deposited layers were characterized: (a) chemical composition (FTIR spectra); (b) morphology (SEM and AFM portraits); and (c) impedance of gas sensors based on NiPcTS and CuPcTS layers in the presence of two analytes - hydrogen and ozone. The prepared sensors exhibit response to 1000 ppm of hydrogen and 100 ppb of ozone even at laboratory temperature.

  4. Bases de Datos Semánticas

    Directory of Open Access Journals (Sweden)

    Irving Caro Fierros

    2016-12-01

    Full Text Available En 1992, cuando Tim Berners-Lee dio a conocer la primera  versión  de  la  Web,  su  visión  a  futuro  era  incorporar metadatos  con  información  semántica  en  las  páginas  Web.  Es precisamente   a   principios   de   este   siglo   que   inicia   el   auge repentino  de  la  Web  semántica  en  el  ambiente  académico  e Internet. El modelo de datos semántico se define como un modelo conceptual que permite definir el significado de los datos a través de  sus  relaciones  con  otros.  En  este  sentido,  el  formato  de representación  de  los  datos  es  fundamental  para  proporcionar información de carácter semántico. La tecnología enfocada en las bases de datos semánticas se encuentra actualmente en un punto de  inflexión,  al  pasar  del  ámbito  académico  y  de  investigación  a ser una opción comercial completa. En este artículo se realiza un análisis  del  concepto  de  base  de  datos  semántica.  También  se presenta  un  caso  de  estudio  donde  se  ejemplifican  operaciones básicas  que  involucran  la  gestión  de  la  información  almacenada en este tipo de base de datos.

  5. Modification of graphene oxide by laser irradiation: a new route to enhance antibacterial activity

    Science.gov (United States)

    Buccheri, Maria A.; D'Angelo, Daniele; Scalese, Silvia; Spanò, Simon F.; Filice, Simona; Fazio, Enza; Compagnini, Giuseppe; Zimbone, Massimo; Brundo, Maria V.; Pecoraro, Roberta; Alba, Anna; Sinatra, Fulvia; Rappazzo, Giancarlo; Privitera, Vittorio

    2016-06-01

    The antibacterial activity and possible toxicity of graphene oxide and laser-irradiated graphene oxide (iGO) were investigated. Antibacterial activity was tested on Escherichia coli and shown to be higher for GO irradiated for at least three hours, which seems to be correlated to the resulting morphology of laser-treated GO and independent of the kind and amount of oxygen functionalities. X-ray photoelectron spectroscopy, Raman spectroscopy, dynamic light scattering and scanning electron microscopy (SEM) show a reduction of the GO flakes size after visible laser irradiation, preserving considerable oxygen content and degree of hydrophilicity. SEM images of the bacteria after the exposure to the iGO flakes confirm membrane damage after interaction with the laser-modified morphology of GO. In addition, a fish embryo toxicity test on zebrafish displayed that neither mortality nor sublethal effects were caused by the different iGO solutions, even when the concentration was increased up to four times higher than the one effective in reducing the bacteria survival. The antibacterial properties and the absence of toxicity make the visible laser irradiation of GO a promising option for water purification applications.

  6. Effects of Er:YAG and Nd:YAP laser irradiation on the surface roughness and free surface energy of enamel and dentin: an in vitro study.

    Science.gov (United States)

    Armengol, Valerie; Laboux, O; Weiss, P; Jean, A; Hamel, H

    2003-01-01

    Sixty-seven extracted molars were selected (134 samples). Dentin and enamel samples were prepared by buccal and lingual surface sectioning to expose a planar enamel or dentin surface. For the roughness study, 80 samples were randomly assigned to eight groups. Enamel and dentin surfaces were etched with a 37% phosphoric acid solution, irradiated with an Er:YAG laser or irradiated with a Nd:YAP laser. Samples were then observed in SEM using BSE. For the free-surface energy study, 54 samples received the same treatment as above. Two contact angle measurements were made on each surface using a goniometer. Data were analyzed by a non-parametric statistical test. Morphological changes on enamel and dentin were greater with acid-etch and Er:YAG laser than with Nd:YAP laser. Free surface energy was significantly greater with acid-etch or Er:YAG laser than with Nd:YAP laser (p < 0.001).

  7. Surface morphologic and structural analysis of IR irradiated silver

    Energy Technology Data Exchange (ETDEWEB)

    Latif, Anwar, E-mail: anwarlatif@uet.edu.p [Department of Physics, University of Engineering and Technology, Lahore 54890 (Pakistan); Khaleeq-ur-Rahman, M.; Rafique, M.S.; Bhatti, K.A. [Department of Physics, University of Engineering and Technology, Lahore 54890 (Pakistan)

    2011-04-15

    The microstructural morphological changes in laser irradiated targets are investigated. Nd:YAG laser (1064 nm, {approx}12 ns nominal, 1.1 MW) is used to irradiate 4 N pure (99.99%) fine polished and annealed silver samples in ambient air and under vacuum {approx}10{sup -6} Torr. The laser spot size and power density at tight focus are 12 {mu}m and 3x10{sup 11} W/cm{sup 2}, respectively. SEM micrographs and X-ray diffractograms of the exposed and unexposed targets reveal the surface texture and structural changes, respectively. Amongst the ablation mechanisms involved, exfoliation and hydrodynamic sputtering are found to be dominant. Surface modifications appear in the form of craters and ripples formation. Heat is conducted non-uniformly through narrow channels at the surface. Thermal stresses induced by the laser do not disturb inter planar distance of the target. On the other hand irradiation causes significant variations in grain size and diffracted X-rays intensities.

  8. Effect of SiO{sub 2} overcoat thickness on laser damage morphology of HfO{sub 2}/SiO{sub 2} Brewster`s angle polarizers at 1064 nm

    Energy Technology Data Exchange (ETDEWEB)

    Stolz, C.J.; Genin, F.Y.; Reitter, T.A.; Molau, N.E. [Lawrence Livermore National Lab., CA (United States); Bevis, R.P.; von Gunten, M.K. [Spectra-Physics Lasers, Inc., Mountain View, CA (United States). Components and Accessories Group; Smith, D.J.; Anzellotti, J.F. [Rochester Univ., NY (United States). Lab. for Laser Energetics

    1997-03-03

    HfO{sub 2}/SiO{sub 2} Brewster`s angle polarizers are being developed at LLNL for the National Ignition Facility. Damage threshold studies using a 3-ns pulse length 1064-nm laser have revealed a number of different damage morphologies such as nodular ejection pits, plasma scalds, flat bottom pits, and overcoat delaminations. Of these laser damage morphologies, delaminations have the most negative impact on the multilayer stability. By selecting the proper SiO{sub 2} overcoat thickness, the delamination morphology is eliminated without significantly modifying the spectra characteristics of the coating and the functional damage threshold is increased by 2-4x. A model of the thermal mechanical response of the overcoats is presented for various SiO{sub 2} overcoat thicknesses. The overcoat thickness influences the electric-field profile resulting in different thermal gradients between the outer SiO{sub 2} and HfO{sub 2} layers. This modeling effort attempts to understand the relation between the thermal stress distribution in the overcoat and the occurrence of delamination.

  9. Skeletal stem cell and bone implant interactions are enhanced by LASER titanium modification

    Energy Technology Data Exchange (ETDEWEB)

    Sisti, Karin E., E-mail: karinellensisti@gmail.com [Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton SO16 6YD (United Kingdom); Biomaterials Group, Institute of Chemistry, São Paulo State University (UNESP), Box 355, Araraquara (Brazil); Federal University of Mato Grosso do Sul (UFMS), Campo Grande (Brazil); Andrés, María C. de; Johnston, David [Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton SO16 6YD (United Kingdom); Almeida-Filho, Edson; Guastaldi, Antonio C. [Biomaterials Group, Institute of Chemistry, São Paulo State University (UNESP), Box 355, Araraquara (Brazil); Oreffo, Richard O.C. [Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton SO16 6YD (United Kingdom)

    2016-05-06

    Purpose: To evaluate the osteo-regenerative potential of Titanium (Ti) modified by Light Amplification by Stimulated Emission of Radiation (LASER) beam (Yb-YAG) upon culture with human Skeletal Stem Cells (hSSCs{sup 1}). Methods: Human skeletal cell populations were isolated from the bone marrow of haematologically normal patients undergoing primary total hip replacement following appropriate consent. STRO-1{sup +} hSSC{sup 1} function was examined for 10 days across four groups using Ti discs: i) machined Ti surface group in basal media (Mb{sup 2}), ii) machined Ti surface group in osteogenic media (Mo{sup 3}), iii) LASER-modified Ti group in basal media (Lb{sup 4}) and, iv) LASER-modified Ti group in osteogenic media (Lo{sup 5}). Molecular analysis and qRT-PCR as well as functional analysis including biochemistry (DNA, Alkaline Phosphatase (ALP{sup 6}) specific activity), live/dead immunostaining (Cell Tracker Green (CTG{sup 7})/Ethidium Homodimer-1 (EH-1{sup 8})), and fluorescence staining (for vinculin and phalloidin) were undertaken. Inverted, confocal and Scanning Electron Microscopy (SEM) approaches were used to characterise cell adherence, proliferation, and phenotype. Results: Enhanced cell spreading and morphological rearrangement, including focal adhesions were observed following culture of hSSCs{sup 1} on LASER surfaces in both basal and osteogenic conditions. Biochemical analysis demonstrated enhanced ALP{sup 6} specific activity on the hSSCs{sup 1}-seeded on LASER-modified surface in basal culture media. Molecular analysis demonstrated enhanced ALP{sup 6} and osteopontin expression on titanium LASER treated surfaces in basal conditions. SEM, inverted microscopy and confocal laser scanning microscopy confirmed extensive proliferation and migration of human bone marrow stromal cells on all surfaces evaluated. Conclusions: LASER-modified Ti surfaces modify the behaviour of hSSCs.{sup 1} In particular, SSC{sup 1} adhesion, osteogenic gene expression, cell

  10. Pulse laser assisted MOVPE for InGaN with high indium content

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, Norihito [Technical Development and Engineering Center, Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama 235-8501 (Japan); Dept. of Applied Chemistry, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Hida, Kennosuke; Kangawa, Yoshihiro; Kumagai, Yoshinao; Koukitu, Akinori [Dept. of Applied Chemistry, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2004-09-01

    In{sub 0.53}Ga{sub 0.47}N film was grown at 600 C by Nd:YAG pulse laser assisted MOVPE. The optical and structural properties of the film were compared with that grown without laser assistance at the same condition. The results of XRD measurements showed that the crystallinity of the film grown with laser was better than that of the one grown without laser. The surface morphology and cross-sectional SEM image of the film grown with laser revealed that there were no In droplets on the film. The band-edge emission of the film grown with laser at room temperature and 77 K was observed at 840 nm. The results of micro-Raman measurement showed that the film grown with laser had better crystalline structure than that of the film grown without laser and the radiative recombination which contributed to photoluminescence mainly occurred at In{sub 0.53}Ga{sub 0.47}N region. Those results imply that pulse laser enhances the surface migration and reaction of elements in spite of low-growth temperature. We suggest that pulse laser assisted technique is effective for low-temperature growth of InGaN with high indium content. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Pulse laser assisted MOVPE for InGaN with high indium content

    Science.gov (United States)

    Kawaguchi, Norihito; Hida, Ken-Nosuke; Kangawa, Yoshihiro; Kumagai, Yoshinao; Koukitu, Akinori

    2004-09-01

    In0.53Ga0.47N film was grown at 600 °C by Nd:YAG pulse laser assisted MOVPE. The optical and structural properties of the film were compared with that grown without laser assistance at the same condition. The results of XRD measurements showed that the crystallinity of the film grown with laser was better than that of the one grown without laser. The surface morphology and cross-sectional SEM image of the film grown with laser revealed that there were no In droplets on the film. The band-edge emission of the film grown with laser at room temperature and 77 K was observed at 840 nm. The results of micro-Raman measurement showed that the film grown with laser had better crystalline structure than that of the film grown without laser and the radiative recombination which contributed to photoluminescence mainly occurred at In0.53Ga0.47N region. Those results imply that pulse laser enhances the surface migration and reaction of elements in spite of low-growth temperature. We suggest that pulse laser assisted technique is effective for low-temperature growth of InGaN with high indium content.

  12. Seafloor earthquake measurement system, SEMS IV

    Energy Technology Data Exchange (ETDEWEB)

    Platzbecker, M.R.; Ehasz, J.P.; Franco, R.J.

    1997-07-01

    Staff of the Telemetry Technology Development Department (2664) have, in support of the U.S. Interior Department Mineral Management Services (MMS), developed and deployed the Seafloor Earthquake Measurement System IV (SEMS IV). The result of this development project is a series of three fully operational seafloor seismic monitor systems located at offshore platforms: Eureka, Grace, and Irene. The instrument probes are embedded from three to seven feet into the seafloor and hardwired to seismic data recorders installed top side at the offshore platforms. The probes and underwater cables were designed to survive the seafloor environment with an operation life of five years. The units have been operational for two years and have produced recordings of several minor earthquakes in that time. Sandia Labs will transfer operation of SEMS IV to MMS contractors in the coming months. 29 figs., 25 tabs.

  13. SEM investigation of heart tissue samples

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, R; Amoroso, M [Physics Department, University of the West Indies, St. Augustine, Trinidad and Tobago, West Indies (Trinidad and Tobago)

    2010-07-01

    We used the scanning electron microscope to examine the cardiac tissue of a cow (Bos taurus), a pig (Sus scrofa), and a human (Homo sapiens). 1mm{sup 3} blocks of left ventricular tissue were prepared for SEM scanning by fixing in 96% ethanol followed by critical point drying (cryofixation), then sputter-coating with gold. The typical ridged structure of the myofibrils was observed for all the species. In addition crystal like structures were found in one of the samples of the heart tissue of the pig. These structures were investigated further using an EDVAC x-ray analysis attachment to the SEM. Elemental x-ray analysis showed highest peaks occurred for gold, followed by carbon, oxygen, magnesium and potassium. As the samples were coated with gold for conductivity, this highest peak is expected. Much lower peaks at carbon, oxygen, magnesium and potassium suggest that a cystallized salt such as a carbonate was present in the tissue before sacrifice.

  14. Metallurgical phenomena in laser finishing: Interdependences between solidification morphologies and hot cracking in laser welding of mostly austenitic materials. Final reportc; Metallkundliche Phaenomene der Laserstrahlmaterialbearbeitung. Teilvorhaben: Zusammenhaenge zwischen Erstarrungsmorphologien und Heissrissentstehung beim Laserschweissen von vornehmlich austenitischen Werkstoffen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Schobbert, H.

    2000-06-01

    Austentic stainless steels are widely used in safety relevant applications such as chemical plant industry or off-shore industry. Due to the rapid development of laser welding processes, the economical efficiency increases and leads to a growing interest in industry for the production of, for example, straight bead welded pipes. A specific problem of laser welding is the economically desirable high welding speed, which leads in austenitic stainless steels to a change of solidification mode and thus, to a restricted hot cracking resistance. Thus, the solidification morphologies of austenitic stainless steels near the eutectic trough during laser welding were investigated. Thereby, the main aspect was the evaluation of a short-term metallurgical kinetic effects under rapid solidification conditions. It was proven that three widely used stainless steels (1.4828, 1.4306, and 1.4404) show a transition of primary solidifcation mode from primary ferritic to primary austenitic solidification depending on the solidification rate. The approximate value of the critical soldification rate can be determined using a newly developed model by analyzing the geometric structures of solidification. The critical solidification rate for the transition of the solidification mode depends on the chemical composition of the base metal. It was shown that austenitic stainless steels have a critical solidification rate of approximately 1 m/min. As a main result, it was proven that a transition of the solidification mode to primary austenitic solidification promotes the predicted susceptibiliyy of hot cracking. For this, a hot cracking test assembly has been developed in order to determine the hot cracking behavior under laser beam conditions. In contrast to existing hot crack tests, a critical strain rate for hot crack initiation could be measured. A classification of the materials with respect to their hot cracking susceptibility under the solidification conditions during laser welding can

  15. Effects of 960 nm diode laser irradiation on dental enamel in vitro: temperature and morphological analysis and evaluation of enamel demineralization; Estudo in vitro dos efeitos promovidos pelo laser de diodo em 960 nm no esmalte dental humano: analise de temperatura, analise morfologica e avaliacao da resistencia a desmineralizacao

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Ilka Tiemy

    2004-07-01

    The aim of this study is to determine the effects of diode laser irradiation on enamel demineralization. To achieve this goal appropriate photon absorbing substances for the laser radiation, safe laser parameters and adequate temperature measuring apparatus had to be determined. Next, the effects of diode laser and acidulated phosphate fluoride on enamel demineralization by calcium content analysis were evaluated with inductively coupled plasma atomic emission spectrometry (ICP-AES). In the first part of the study, five dyes consisting of vegetable coal diluted in five different liquids were analyzed and vegetable coal diluted in physiological solution was chosen for use as absorber. Methodologies to measure pulp chamber temperature were evaluated and modeling clay was chosen as fixture for the enamel samples held at body temperature. In the second part of the study, different energy density parameters (1.8 J/cm{sup 2}, 3.7 J/cm{sup 2}, 5.6 J/cm{sup 2}, 7.4 J/cm{sup 2} and 9.3 J/cm{sup 2}) exposure times (10, 15, 20, 25 e 30 seconds) and time intervals between dye application and laser irradiation (5, 30, 60, 90 e 120 seconds) were evaluated with respect to temperature changes in the pulp chamber. The enamel morphology was analyzed by scanning electron microscopy. Acid resistance was measured using seventy five enamel specimens, divided in five groups (control, fluoride, laser, laser + fluoride and fluoride + laser). The amount of calcium lost during demineralization in lactic acid was measured by ICP-AES. The results obtained in this experiment permit the conclusion that diode laser irradiation did not increase acid resistance. When associated with fluoride, the acid resistance did not differ from the results obtained with fluoride alone. (author)

  16. Scanning electron microscopy study of cavity preparation in deciduous teeth using the Er:YAG laser with different powers.

    Science.gov (United States)

    Zhang, Sun; Chen, Tao; Ge, Li-hong

    2012-01-01

    Using scanning electron microscopy (SEM) we evaluated the morphology of cavity surfaces in deciduous teeth prepared in vitro with the Er:YAG laser with different power parameters. Eight extracted cavity-free deciduous teeth with an intact crown were prepared using a traditional handpiece or an Er:YAG laser with different parameters (10 Hz/200 mJ, 10 Hz/300 mJ and 10 Hz/400 mJ). Samples were then processed and cavity surface morphology was evaluated by SEM to detect open dentinal tubules, or melting or cracking of the dentin. SEM showed that laser cavity preparation in deciduous teeth using different parameters left no smear layer and the dentinal tubules were clear. Dentin melting was not seen after cavity preparation at 200 mJ or 300 mJ, while visible dentin melting and cracks were detected at 400 mJ. The use of the laser at 10 Hz/200 mJ and 10 Hz/300 mJ for cavity preparation in deciduous teeth is safe and effective, but higher powers may damage the dentin.

  17. Viewing Integrated-Circuit Interconnections By SEM

    Science.gov (United States)

    Lawton, Russel A.; Gauldin, Robert E.; Ruiz, Ronald P.

    1990-01-01

    Back-scattering of energetic electrons reveals hidden metal layers. Experiment shows that with suitable operating adjustments, scanning electron microscopy (SEM) used to look for defects in aluminum interconnections in integrated circuits. Enables monitoring, in situ, of changes in defects caused by changes in temperature. Gives truer picture of defects, as etching can change stress field of metal-and-passivation pattern, causing changes in defects.

  18. SEM observations of an IUD from a patient with Actinomyces-like organisms on papanicolaou smear.

    Science.gov (United States)

    Keith, L; Method, M; Bailey, R; Bockoff, C; Hidvegi, D; Puleo, M

    1986-01-01

    Scanning electron microscopy (SEM) was used to study an IUD from an asymptomatic patient with Actinomyces-like organisms on Papanicolaou smear and in whom Actinomyces israelii was determined to be present in cervical smears. The objective was to determine if there were any variations in surface morphology that might be correlated with the Actinomyces-like organisms. SEM revealed numerous areas of thick surface encrustation. The surface morphology of the IUD fragments showed basic similarities to the morphologies observed in other cases. Encrustations were attached to the arms and stem of the device. A unique finding was apparently biological material adherent to a fragment of encrusted material. Filamentous structures radiated perpendicularly from a central core. These filaments resembled Actinomyces-like organisms in the patient's Pap smear. Also of interest was a delicate network of hair-like structures at the bottom of a naturally occurring space in the surface encrustation.

  19. Laser cutting of thick sheet metals: Residual stress analysis

    Science.gov (United States)

    Arif, A. F. M.; Yilbas, B. S.; Aleem, B. J. Abdul

    2009-04-01

    Laser cutting of tailored blanks from a thick mild steel sheet is considered. Temperature and stress field in the cutting sections are modeled using the finite element method. The residual stress developed in the cutting section is determined using the X-ray diffraction (XRD) technique and is compared with the predictions. The structural and morphological changes in the cut section are examined using the optical microscopy and scanning electron microscopy (SEM). It is found that temperature and von Mises stress increase sharply in the cutting section, particularly in the direction normal to the cutting direction. The residual stress remains high in the region close to the cutting section.

  20. Morphology-Dependent Hardness of Cr7C3-Ni-Rich Alloy Composite vs Orientation Independent Hardness of Cr7C3 Primary Phase in a Laser Clad Microstructure

    Science.gov (United States)

    Venkatesh, Lakshmi Narayanan; Suresh Babu, Pitchuka; Gundakaram, Ravi Chandra; Doherty, Roger D.; Joshi, Shrikant V.; Samajdar, Indradev

    2017-04-01

    Microstructural evolution with superheating was studied in chromium carbide-nickel coatings deposited by laser cladding. At lower superheating, selective growth of direction from the high density of Cr7C3 grains nucleated resulted in a columnar structure with (0001) texture. Increased superheating lead to the loss of columnar structure as well as the (0001) texture. The hexagonal Cr7C3 showed an unusual isotropic nanoindentation hardness evidently correlated with its low c/ a ratio. However, the rod-like morphology of the carbide dendrites resulted in significant anisotropy in the hardness of the composite.

  1. Investigation of meso-failure behaviors of Jinping marble using SEM with bending loading system

    Institute of Scientific and Technical Information of China (English)

    Jianping Zuo; Xu Wei; Jianliang Pei; Xiaoping Zhao

    2015-01-01

    In this study, the meso-failure mechanism and fracture surface of Jinping marble were investigated by means of scanning electron microscope (SEM) with bending loading system and laser-scanner equip-ment. The Yantang and Baishan marbles specimens from Jinping II hydropower station were used. Test results show that the fracture toughness and mechanical behaviors of Yantang marble were basically higher than those of Baishan marble. This is mainly due to the fact that Baishan marble contains a large percentage of dolomite and minor mica. Crack propagation path and fracture morphology indicated that the direction of tensile stress has a significant effect on the mechanical behaviors and fracture toughness of Baishan marble. For Yantang and Baishan marbles, a large number of microcracks around the main crack tip were observed when the direction of tensile stress was parallel to the bedding plane. Conversely, few microcracks occurred when the direction of tensile stress was perpendicular to the bedding plane. The presence of a large number of microcracks at the main crack tip decreased the global fracture toughness of marble. The results of three-point bending tests showed that the average bearing capacity of intact marble is 3.4 times the notched marble, but the ductility property of the defective marble after peak load is better than that of the intact marble. Hence, large deformation may be generated before failure of intact marbles at Jinping II hydropower station. The fractal dimension of fracture surface was also calculated by the cube covering method. Observational result showed that the largest fractal dimension of Yantang marble is captured when the direction of tensile stress is parallel to the bedding plane. However, the fractal dimension of fracture surface of Yantang and Baishan marbles with tensile stress vertical to the bedding plane is relatively small. The fractal dimension can also be used to characterize the roughness of fracture surface of rock

  2. Optical Defect in GaN-Based Laser Diodes Detected by Cathodoluminescence

    Institute of Scientific and Technical Information of China (English)

    ZHAO Lu-Bing; WU Jie-Jun; XU Ke; BAO Sui; YANG Zhi-Jian; PAN Yao-Bo; HU Xiao-Dong; ZHANG Guo-Yi

    2008-01-01

    @@ GaN-based laser diodes (LDs) with 399 nm wavelength are grown on sapphire substrates by metal organic chemical vapour deposition (MOCVD).Electroluminescence spectra of the fabricated LDs show that the LDs from some grown wafers failed to emit laser.The SEM and XRD results show the similar surface morphology and interface qualities of multi quantum wells (MQWs) and super-lattices between LDs that succeed and fail to emit laser.However, the cathodoluminescence (CL) measurements reveal a kind of optical defect rather than structural defect in un-emitted LDs.Further depth-dependent CL imaging observation indicates that such optical defects originate from the MQWs to the surface of LDs as a non-irradiative recombination centre that should cause the failure of laser emitting of LDs.

  3. Modification of anodised aluminium surfaces using a picosecond fibre laser for printing applications.

    Science.gov (United States)

    Ansari, I A; Watkins, K G; Sharp, M C; Hutchinson, R A; Potts, R M; Clowes, J

    2012-06-01

    The use of an ultrafast fibre laser at a wavelength of 1064 nm has allowed the surface modification of anodised aluminium plates coated with a 2 micron thick anodised layer for potential industrial applications. The micro- and nano-scale structuring of the anodised aluminium using picosecond pulses of approximately 25 ps duration at 200 kHz repetition rate was investigated. The interaction of the laser with the substrate created a hydrophilic surface, giving a contact angle of less than 10 degrees. On examination under a Scanning Electron Microscope (SEM), a morphology created due to laser induced spallation was observed. It has been found that these laser processed hydrophilic surfaces revert to a hydrophobic state with time. This has potential for application in the printing industry and offers reusability and sustainability of the process materials. This has been confirmed in initial trials.

  4. Semântica expressivista = Expressivist semantics

    Directory of Open Access Journals (Sweden)

    Mendonça, Wilson John Pessoa

    2016-01-01

    Full Text Available O programa semântico do expressivismo surgiu como uma tentativa de fundamentar a visão não-cognitivista do discurso ético, mas logo foi generalizado de forma a cobrir a linguagem normativa em geral. Ele promete desenvolver uma alternativa global à abordagem clássica da semântica das condições de verdade: uma teoria não-factualista, baseada na pragmática, do significado linguístico. Os expressivistas veem o conteúdo das sentenças normativas como determinado por seu uso primário, que é não-descritivo. As versões tradicionais da semântica expressivista procedem associando sistematicamente às sentenças normativas as atitudes mentais que elas convencionalmente expressam. Elas assumem que, se as sentenças simples expressam atitudes, a aplicação a essas sentenças dos conectivos da lógica proposicional ou da ligação de variáveis resulta em sentenças complexas que também expressam atitudes. O núcleo do presente trabalho avalia algumas tentativas influentes de desenvolvimento do programa expressivista, focando em um problema discutido com veemência na literatura: o “problema da negação para o expressivismo”. Algumas abordagens propostas nos últimos anos, baseadas na rejeição da assunção central do expressivismo tradicional, são consideradas em detalhes. Embora uma avaliação definitiva dessas abordagens inovadoras como explicações satisfatórias do funcionamento da linguagem normativa não possa ainda ser alcançada, o trabalho afirma que há razões para otimismo

  5. Effect of laser treatment on the attachment and viability of mesenchymal stem cell responses on shape memory NiTi alloy.

    Science.gov (United States)

    Chan, C W; Hussain, I; Waugh, D G; Lawrence, J; Man, H C

    2014-09-01

    The objectives of this study were to investigate the effect of laser-induced surface features on the morphology, attachment and viability of mesenchymal stem cells (MSCs) at different periods of time, and to evaluate the biocompatibility of different zones: laser-melted zone (MZ), heat-affected zone (HAZ) and base metal (BM) in laser-treated NiTi alloy. The surface morphology and composition were studied by scanning electron microscope (SEM) and X-ray photoemission spectroscopy (XPS), respectively. The cell morphology was examined by SEM while the cell counting and viability measurements were done by hemocytometer and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The results indicated that the laser-induced surface features, such as surface roughening, presence of anisotropic dendritic pattern and complete surface Ni oxidation were beneficial to improve the biocompatibility of NiTi as evidenced by the highest cell attachment (4 days of culture) and viability (7 days of culture) found in the MZ. The biocompatibility of the MZ was the best, followed by the BM with the HAZ being the worst. The defective and porous oxide layer as well as the coarse grained structure might attribute to the inferior cell attachment (4 days of culture) and viability (7 days of culture) on the HAZ compared with the BM which has similar surface morphology. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Nd:YAG laser-induced morphology change and photothermal conversion of gold nanorods with potential application in the treatment of port-wine stain.

    Science.gov (United States)

    Xing, Linzhuang; Chen, Bin; Li, Dong; Ma, Jun; Wu, Wenjuan; Wang, Guoxiang

    2017-04-01

    Based on the principle of selective photothermolysis, 1064 nm Nd:YAG laser has great potential for the treatment of deeper and larger PWS. However, the clinical effectiveness is limited because of the weak absorption of blood to Nd:YAG laser. The aim of this study is to obtain the optimal irradiation conditions to effectively destroy vascular lesions with the assistance of PEG-modified gold NRs to enhance blood absorption of Nd:YAG laser. In our study, PEG-modified gold NRs were prepared by the seeded growth method. Gold NRs after exposure to Nd:YAG laser were characterized using absorption spectra and transmission electron microscope images. The tissue-like phantom containing a glass capillary with blood was prepared and exposed to Nd:YAG laser to investigate the laser energy density and pulse number required for blood coagulation before and after the addition of gold NRs in blood. The results show that the millisecond Nd:YAG laser irradiation does not result in the shape change of gold NRs. After injection of gold NRs into the bloodstream (4.60 mg/kg), the absorbance of blood at 1064 nm increased 3.9 times. The threshold energy density for the treatment of PWS decreased by 33% (from 30 to 20 J/cm(2)). Our findings provide an experimental guide for choosing laser parameters and gold NRs concentration for the treatment of deeper and larger PWS with the assistance of PEG-modified gold NRs in vivo in the future.

  7. Raman-in-SEM, a multimodal and multiscale analytical tool: performance for materials and expertise.

    Science.gov (United States)

    Wille, Guillaume; Bourrat, Xavier; Maubec, Nicolas; Lahfid, Abdeltif

    2014-12-01

    The availability of Raman spectroscopy in a powerful analytical scanning electron microscope (SEM) allows morphological, elemental, chemical, physical and electronic analysis without moving the sample between instruments. This paper documents the metrological performance of the SEMSCA commercial Raman interface operated in a low vacuum SEM. It provides multiscale and multimodal analyses as Raman/EDS, Raman/cathodoluminescence or Raman/STEM (STEM: scanning transmission electron microscopy) as well as Raman spectroscopy on nanomaterials. Since Raman spectroscopy in a SEM can be influenced by several SEM-related phenomena, this paper firstly presents a comparison of this new tool with a conventional micro-Raman spectrometer. Then, some possible artefacts are documented, which are due to the impact of electron beam-induced contamination or cathodoluminescence contribution to the Raman spectra, especially with geological samples. These effects are easily overcome by changing or adapting the Raman spectrometer and the SEM settings and methodology. The deletion of the adverse effect of cathodoluminescence is solved by using a SEM beam shutter during Raman acquisition. In contrast, this interface provides the ability to record the cathodoluminescence (CL) spectrum of a phase. In a second part, this study highlights the interest and efficiency of the coupling in characterizing micrometric phases at the same point. This multimodal approach is illustrated with various issues encountered in geosciences.

  8. Principios sobre semáforos

    OpenAIRE

    Valencia Alaix, Víctor Gabriel

    2000-01-01

    Debido a la ausencia de una publicación que reuniese los aspectos más relevantes sobre semáforos y en el marco académico sobre ingeniería de tránsito de los cursos de pregrado y posgrado en Vías y Transporte de la Universidad Nacional de Colombia - Sede Medellín, se ha preparado este documento como guía introductoria a dicho tema. En su preparación se han recogido los tópicos principales de varias publicaciones internacionales y nacionales, además, su desarrollo ha considerado la experi...

  9. O ciberativismo sem bússola

    Directory of Open Access Journals (Sweden)

    Francisco Rüdiger

    2014-07-01

    Full Text Available Questiona-se no texto se uma abordagem que, no essencial, relata a trajetória do chamado ciberativismo de acordo com seus próprios termos se justifica academicamente ou, em vez disso, se mantém prisioneira de uma mitologia que o fenômeno, em si mesmo, já construiu e, por isso, autoriza seus sujeitos a dispensarem sem prejuízo eventual contribuição de origem universitária.

  10. Excimer laser pretreatment and metallization of polymers

    Science.gov (United States)

    Horn, H.; Beil, S.; Wesner, D. A.; Weichenhain, R.; Kreutz, E. W.

    1999-05-01

    Metal/polymer adhesion is a crucial factor of many applications in microelectronic or microsystem technologies. It depends on chemical and structural properties of the interface, often involving just a few atomic layers. Adhesion can be influenced by various pretreatments prior to metal deposition, e.g. thermal treatment, chemical etching or exposure to reactive plasmas. Irradiation with pulsed UV-laser radiation and or UV-excimer lamps can also affect adhesion and offers several technical advantages, among them area selective pretreatment and subsequent metallization. The pretreatment of polymer surfaces by UV-radiation is investigated as an alternative technique to common wet chemical, plasma or other pretreatment methods. Chemical and morphological changes in the polymer surface are investigated with poly(butylene terephthalate) (PBT) as a model substance, containing UV-absorbing (aromatic) chromophoric groups. Chemical changes in the surface are investigated via X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR). Analysis of the morphological changes in the polymer surface is done via optical microscopy and scanning electron microscopy (SEM). The metallization of polymers pretreated by excimer laser radiation is performed via electroless plating of nickel followed by electrolytically deposited copper. The influence of excimer laser irradiation of the polymer on the adhesion of the metal overlayers is measured by tape and peel tests.

  11. Assessing the utility of FIB-SEM images for shale digital rock physics

    Science.gov (United States)

    Kelly, Shaina; El-Sobky, Hesham; Torres-Verdín, Carlos; Balhoff, Matthew T.

    2016-09-01

    is compromised at the expense of detailed, but often unconnected, nanopore morphology. Further, we find that it is necessary to acquire several local FIB-SEM or BIB-SEM images and correlate their extracted geometric properties to improve the likelihood of achieving representative values of porosity and organic matter volume. Our work indicates that FIB-SEM images of microscale volumes of shale are a qualitative tool for petrophysical and transport analysis. Finally, we offer alternatives for quantitative pore-scale assessments of shale.

  12. Enhancing structural integrity of adhesive bonds through pulsed laser surface micro-machining

    KAUST Repository

    Diaz, Edwin Hernandez

    2015-06-01

    Enhancing the effective peel resistance of plastically deforming adhesive joints through laser-based surface micro-machining Edwin Hernandez Diaz Inspired by adhesion examples commonly found in nature, we reached out to examine the effect of different kinds of heterogeneous surface properties that may replicate this behavior and the mechanisms at work. In order to do this, we used pulsed laser ablation on copper substrates (CuZn40) aiming to increase adhesion for bonding. A Yb-fiber laser was used for surface preparation of the substrates, which were probed with a Scanning Electron Microscope (SEM) and X-ray Photoelectron Spectroscopy (XPS). Heterogeneous surface properties were devised through the use of simplified laser micromachined patterns which may induce sequential events of crack arrest propagation, thereby having a leveraging effect on dissipation. The me- chanical performance of copper/epoxy joints with homogeneous and heterogeneous laser micromachined interfaces was then analyzed using the T-peel test. Fractured surfaces were analyzed using SEM to resolve the mechanism of failure and adhesive penetration within induced surface asperities from the treatment. Results confirm positive modifications of the surface morphology and chemistry from laser ablation that enable mechanical interlocking and cohesive failure within the adhesive layer. Remarkable improvements of apparent peel energy, bond toughness, and effective peel force were appreciated with respect to sanded substrates as control samples.

  13. Laser Treatment of Cotton Fabric for Durable Antibacterial Properties of Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Shirin Nourbakhsh

    2012-07-01

    Full Text Available In the present study, cotton fabric was exposed to laser exposure at different energy levels and then the silver nanoparticles were coated on untreated and laser treated cotton fabrics. Methylene blue dye was used to detect the presence of carboxylic acid groups (-COO on laser treated cotton and the dye absorption results were determined spectrophotometrically. ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy analysis and antibacterial tests were carried out to investigate the silver ion content and bactericidal properties of silver nanoparticles on cotton fabrics. Infrared spectroscopy (FTIR/ATR analysis and scanning electron microscopy (SEM were used to identify chemical changes and to study the morphology of the surface of the fibers. EDAX (Energy Dispersive X-ray Spectroscopy analysis was calculated for SEM micrographs. The results showed according to the higher uptake of methylene blue dye that the negative charge of the carboxylic acid groups had been created by laser treatment. Although the FTIR spectroscopy results did not show an increase in carboxylic acid groups, the cationic dye absorption increased. The durability of the Ag+ ion particles on repeated laundered laser treated cotton was proven by antibacterial and ICP tests, particularly when the laser energy was increased.

  14. Preparation and Characterization of Alumina Nanoparticles in Deionized Water Using Laser Ablation Technique

    Directory of Open Access Journals (Sweden)

    Veeradate Piriyawong

    2012-01-01

    Full Text Available Al2O3 nanoparticles were synthesized using laser ablation of an aluminum (Al target in deionized water. Nd:YAG laser, emitted the light at a wavelength of 1064 nm, was used as a light source. The laser ablation was carried out at different energies of 1, 3, and 5 J. The structure of ablated Al particles suspended in deionized water was investigated using X-ray diffraction (XRD. The XRD patterns revealed that the ablated Al particles transformed into γ-Al2O3. The morphology of nanoparticles was investigated by field emission scanning electron microscopy (FE-SEM. The FE-SEM images showed that most of the nanoparticles obtained from all the ablated laser energies have spherical shape with a particle size of less than 100 nm. Furthermore, it was observed that the particle size increased with increasing the laser energy. The absorption spectra of Al2O3 nanoparticles suspended in deionized water were recorded at room temperature using UV-visible spectroscopy. The absorption spectra show a strong peak at 210 nmarising from the presence of Al2O3 nanoparticles. The results on absorption spectra are in good agreement with those investigated by XRD which confirmed the formation of Al2O3 nanoparticles during the laser ablation of Al target in deionized water.

  15. Evaluation of micromorphological changes in tooth enamel after mechanical and ultrafast laser preparation of surface cavities.

    Science.gov (United States)

    Luengo, Ma Cruz Lorenzo; Portillo, M; Sánchez, J M; Peix, M; Moreno, P; García, A; Montero, J; Albaladejo, A

    2013-01-01

    The aim of this in vitro study was to evaluate the morphological changes that occur in tooth enamel after mechanical instrumentation and after femtosecond laser irradiation with different parameters via light and scanning electron microscopy (SEM). Twelve totally impacted third molars were collected and sectioned to provide several cut surfaces. These surfaces were exposed to infrared (λ = 795 nm, 120 fs, 1-kHz repetition rate, maximum mean power 1 W) laser pulses and machined by means of a conventional mechanical technique. Two very different geometrical patterns were performed with femtosecond laser pulses: shallow rectangular cavities and deep cylindrical ones. The results of both machining procedures were examined using light and scanning electron microscopy. The SEM images show the femtosecond laser ability to produce high-precision cavities in tooth enamel. No signs of collateral damage, burning, melting, or cracks were observed despite the far different laser pulse energies used (ranging from 7 to 400 μJ), unlike what is seen with conventional mechanical techniques. The femtosecond laser has the potential to become an optimal tool for the treatment of dental decay and as an alternative to the conventional drill to reduce mechanical damage during removal of the hard dental tissue.

  16. Whole mount nuclear fluorescent imaging: convenient documentation of embryo morphology.

    Science.gov (United States)

    Sandell, Lisa L; Kurosaka, Hiroshi; Trainor, Paul A

    2012-11-01

    Here, we describe a relatively inexpensive and easy method to produce high quality images that reveal fine topological details of vertebrate embryonic structures. The method relies on nuclear staining of whole mount embryos in combination with confocal microscopy or conventional wide field fluorescent microscopy. In cases where confocal microscopy is used in combination with whole mount nuclear staining, the resulting embryo images can rival the clarity and resolution of images produced by scanning electron microscopy (SEM). The fluorescent nuclear staining may be performed with a variety of cell permeable nuclear dyes, enabling the technique to be performed with multiple standard microscope/illumination or confocal/laser systems. The method may be used to document morphology of embryos of a variety of organisms, as well as individual organs and tissues. Nuclear stain imaging imposes minimal impact on embryonic specimens, enabling imaged specimens to be utilized for additional assays.

  17. A Study on Micro-morphology and Elemental Analyses of Particulate Matter Collected at Exhaust Pipe of Automobiles and Coal Burning Chimney by SEM-EDX%汽车尾气管和燃煤烟囱颗粒物微形貌及其X-射线能谱析研究

    Institute of Scientific and Technical Information of China (English)

    陈满荣; 张卫国; 俞立中

    2016-01-01

    用扫描电镜及X-射线能谱(SEM-EDX)分析方法,对山西省朔州市区汽车尾气管末端和燃煤烟囱上部颗粒物样品的微形貌和化学元素进行了分析.结果显示,尾气管颗粒单体为球、团状,聚集体微形为棉絮状、层叠状集合体;烟囱颗粒物为不规则片状单粒和银耳状、层叠状集合体.二者EDX特征峰显示颗粒物的主要元素为:O、Si、Al、Fe、Pb、Na、Mg、Ca、P、Ti、Cd等.研究表明,汽车尾气颗粒物中的元素,O、Si 、Al平均含量最高.其比例之和为所测得元素含量的76.19%.Pb平均含量位居第4;燃煤烟囱颗粒物中O平均含量最高,其次是S、Cl、si、Pb,其中Pb的平均含量高于汽车尾气颗粒物中Pb的平均含量.样品磁化率的测试对区分这2种颗粒物,防治大气颗粒物(PM)污染有一定的技术指导意义.

  18. Alterações morfológicas em instrumentos rotatórios de níquel titânio protaper®, analisados por MEV: efeito da implantação de íons nitrogênio = Morphological alterations of rotary nickel-titanium protaper® instruments analyzed by SEM: effect of nitrogen ion implantation

    Directory of Open Access Journals (Sweden)

    Becker, Alex Niederauer

    2014-01-01

    Full Text Available Objetivo: O presente estudo analisou, através do Microscópio Eletrônico de Varredura [MEV], as alterações morfológicas de instrumentos rotatórios ProTaper SX, submetidos à implantação de íons de nitrogênio . Métodos: Foram utilizados trinta instrumentos ProTaper SX divididos em três grupos de 10 instrumentos cada. O grupo A foi submetido a uma dose de 1,0×1017 íons de nitrogênio/cm² e energia de 100 KeV. O grupo B foi submetido a uma dose de 1,0×1017 íons de nitrogênio/cm² e energia de 200 KeV. O grupo C foi composto por dez instrumentos não submetidos ao processo de implantação iônica. Cada lima instrumentou cinco blocos de canais simulados de resina acrílica, com a técnica Brushing Motion. Todos os instrumentos SX foram analisados no Microscópio Eletrônico de Varredura antes do uso, após 60 s e 300 s de uso. Resultados: A perda de material e a distorção foram estatisticamente similares em todos os grupos. Um instrumento do grupo A, um instrumento do grupo B e três instrumentos do grupo C fraturaram durante o uso. Conclusão: A Implantação Iônica de íons de nitrogênio melhorou moderadamente o desempenho dos instrumentos ProTaper SX. Instrumentos implantados apresentaram melhores resultados do que o grupo controle, sem diferença estatisticamente significativa

  19. In vitro effect of Q-switched Nd:YAG laser exposure on morphology, hydroxyapatite composition and microhardness properties of human dentin

    Directory of Open Access Journals (Sweden)

    Retna Apsari

    2011-12-01

    Full Text Available Background: A Q-switched Nd:YAG laser was employed as a source of ablation. The fundamental wavelength of the laser is 1064 nm, with pulse duration of 8 nanosecond operates with uniphase mode of TEM00. In the following experiments, dentin samples (without caries and plaque are exposed to pulse laser with Q-switching effect at various energy dose. Purpose: The aim of this study was to investigate the effect of laser ablation on dentin samples using Q-switched Nd:YAG laser exposure. Methods: The laser was operated in repetitive mode with frequency of 10 Hz. The energy dose of the laser was ranging from 13.9 J/cm2, 21.2 J/cm2 and 41.7 J/cm2. The target material comprised of human dentin. The laser was exposed in one mode with Q-switched Nd:YAG laser. Energy delivered to the target through free beam technique. The exposed human dentin was examined by using x-ray diffraction (XRD and fluoresence scanning electron microscopy for energy dispersive (FESEM-EDAX. Microhardness of human dentin were examined by using microhardness vickers test (MVT. Results: The result obtained showed that the composition of hydroxyapatite of the dentin after exposed by Q-switched Nd:YAG laser are 75.02% to 78.21%, with microhardness of 38.7 kgf/mm2 to 86.6 kgf/mm2. This indicated that exposed pulsed Nd:YAG laser on the human dentin attributed to the phototermal effect. The power density created by the Q-switched Nd:YAG laser enables the heat to produce optical breakdown (melting and hole associated with plasma formation and shock wave propagation, from energy dose of 21.2 J/cm2. From XRD analysis showed that the exposure of Nd:YAG laser did not involve in changing the crystal structure of the dentin, but due to photoablation effect. Conclusion: In conclusion, the application of Q-switched Nd:YAG laser as contactless drills in dentistry should be regarded as an alternative to the classical mechanical technique to improve the quality of the dentin treatment.Latar belakang

  20. Scanning Electron Microscopy (SEM) Procedure for HE Powders on a Zeiss Sigma HD VP SEM

    Energy Technology Data Exchange (ETDEWEB)

    Zaka, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-11-15

    This method describes the characterization of inert and HE materials by the Zeiss Sigma HD VP field emission Scanning Electron Microscope (SEM). The SEM uses an accelerated electron beam to generate high-magnification images of explosives and other materials. It is fitted with five detectors (SE, Inlens, STEM, VPSE, HDBSD) to enable imaging of the sample via different secondary electron signatures, angles, and energies. In addition to imaging through electron detection, the microscope is also fitted with two Oxford Instrument Energy Dispersive Spectrometer (EDS) 80 mm detectors to generate elemental constituent spectra and two-dimensional maps of the material being scanned.

  1. Tillandsia stricta Sol (Bromeliaceae) leaves as monitors of airborne particulate matter-A comparative SEM methods evaluation: Unveiling an accurate and odd HP-SEM method.

    Science.gov (United States)

    de Oliveira, Martha Lima; de Melo, Edésio José Tenório; Miguens, Flávio Costa

    2016-09-01

    Airborne particulate matter (PM) has been included among the most important air pollutants by governmental environment agencies and academy researchers. The use of terrestrial plants for monitoring PM has been widely accepted, particularly when it is coupled with SEM/EDS. Herein, Tillandsia stricta leaves were used as monitors of PM, focusing on a comparative evaluation of Environmental SEM (ESEM) and High-Pressure SEM (HPSEM). In addition, specimens air-dried at formaldehyde atmosphere (AD/FA) were introduced as an SEM procedure. Hydrated specimen observation by ESEM was the best way to get information from T. stricta leaves. If any artifacts were introduced by AD/FA, they were indiscernible from those caused by CPD. Leaf anatomy was always well preserved. PM density was determined on adaxial and abaxial leaf epidermis for each of the SEM proceedings. When compared with ESEM, particle extraction varied from 0 to 20% in air-dried leaves while 23-78% of particles deposited on leaves surfaces were extracted by CPD procedures. ESEM was obviously the best choice over other methods but morphological artifacts increased in function of operation time while HPSEM operation time was without limit. AD/FA avoided the shrinkage observed in the air-dried leaves and particle extraction was low when compared with CPD. Structural and particle density results suggest AD/FA as an important methodological approach to air pollution biomonitoring that can be widely used in all electron microscopy labs. Otherwise, previous PM assessments using terrestrial plants as biomonitors and performed by conventional SEM could have underestimated airborne particulate matter concentration.

  2. 选区激光熔化成型过程中熔线形貌的优化%Optimization of Molten Metal Line Morphology in Selective Laser Melting

    Institute of Scientific and Technical Information of China (English)

    吴伟辉; 杨永强

    2012-01-01

    针对选区激光熔化成型过程中可能影响熔线形貌的因素,研究了熔融金属表面张力、成型过程中飞溅物及扫描速度等激光加工参数对熔线形貌的影响,获得了熔线形貌的优化成型工艺,并最终以此工艺成功成型了一个金属零件.分析表明,该零件尺寸精度达±0.1 mm,表面粗糙度达Ra30 μm,表面平整,熔线搭接均匀,熔线堆垒效果理想.%Aimed at the possible effecting factors on the shape and morphology of molten metal line during selective laser melting (SLM), the effects of surface tension of molten metal, splashing objects in molding process and laser processing parameters (such as scanning speed, layer thickness) on the shape and morphology of molten metal line were studied, and thus a optimization process for the morphology of molten metal line was obtained. A metal part was built successfully by the process. The analyzing shows that the dimensional accuracy of the part is up to ±0.1 mm and the surface roughness up to Ra30 μrn, with smooth surface, even metal lines overlapping and satisfactory fuse stackable results.

  3. In-situ SEM electrochemistry and radiolysis

    DEFF Research Database (Denmark)

    Møller-Nilsen, Rolf Erling Robberstad; Norby, Poul

    Electron microscopy is a ubiquitous technique to see effects which are too small to see with traditional optical microscopes. Recently it has become possible to also image liquid samples by encapsulating them from the vacuum of the microscope and a natural evolution from that has been to include...... microelectrodes on the windows to enable studies of electrohcemical processes. In this way it is possible to perform in-situ electrochemical experiments such as electroplating and charge and discharge analysis of battery electrodes. In a typical liquid cell, electrons are accelerated to sufficiently high energies...... to traverse a thin window made by a silicon nitride membrane, and interact with the sample immersed in liquid. In transmission electron microscopy (TEM) the majority of the electrons continue through the sample to form an image. In scanning electron microscopy (SEM) a fraction of the electrons...

  4. SEMS: System for Environmental Monitoring and Sustainability

    Science.gov (United States)

    Arvidson, Raymond E.

    1998-01-01

    The goal of this project was to establish a computational and data management system, SEMS, building on our existing system and MTPE-related research. We proposed that the new system would help support Washington University's efforts in environmental sustainability through use in: (a) Problem-based environmental curriculum for freshmen and sophomores funded by the Hewlett Foundation that integrates scientific, cultural, and policy perspectives to understand the dynamics of wetland degradation, deforestation, and desertification and that will develop policies for sustainable environments and economies; (b) Higher-level undergraduate and graduate courses focused on monitoring the environment and developing policies that will lead to sustainable environmental and economic conditions; and (c) Interdisciplinary research focused on the dynamics of the Missouri River system and development of policies that lead to sustainable environmental and economic floodplain conditions.

  5. [Clinico-morphological assessment of early and late results of laser therapy of the anastomosis area after radical surgeries for stomach cancer].

    Science.gov (United States)

    Zyrianov, B N; Vusik, M V; Kritskaia, N G

    2003-01-01

    The study included 52 patients after gastrectomy for carcinoma of the proximal part of the stomach. Endoscopic laser therapy was made in 32 patients to reduce inflammation in the anastomosis zone 2-3 weeks after surgery. Drug therapy was made in 20 patients within the same time period. Histochemical study of the biopsy material of esophageal and intestinal part of the anastomosis was carried out. It is revealed that application of copper vapor laser early after surgery reduces edema and inflammation in the anastomosis zone for 2 weeks as well as accelerates the growth of granulation tissue forming a delicate scar thus preventing formation of scar stenosis.

  6. [Dental tissue-composite bonding. SEM study].

    Science.gov (United States)

    Menghini, P; Piacentini, C; Marchetti, C

    1991-05-31

    The Authors investigated the different operative methods effects in the transition zone between human fresh teeth calcified tissues and a composite material. Morphological observations, done by means of standard and back scattered scanning electron microscopy, demonstrated the Gluma adhesion system efficiency towards enamel and dentin if manufacturing's applying systems are carefully followed, by showing a structure with no solutions of continuity between tooth and restoration.

  7. Structural, compositional and morphological studies of thermally evaporated MoO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Senthilkumar, R., E-mail: raviganesa@rediffmail.com, E-mail: gravicrc@gmail.com; Ravi, G., E-mail: raviganesa@rediffmail.com, E-mail: gravicrc@gmail.com [Department of Physics, Alagappa University, Karaikudi - 630003 (India)

    2014-04-24

    Molybdenum oxide (MoO{sub 3}) nanostructures were grown on different substrates such as glass, indium tin oxide coated glass and fluorine doped glass by thermal evaporation of MoO{sub 3} powder at elevated temperature (750°C) using tube furnace without any catalyst and then by subsequent O{sub 2}/Ar flow rate. The morphology, composition and crystal structure were examined by using SEM, EDAX, Laser Raman and XRD. The films are polycrystalline with well-defined diffraction peaks and it consist of MoO{sub 3} with α-orthorhombic structure. The synthesized MoO{sub 3} belongs to different morphologies, generally nanobelt and nanohunk structures. The EDAX spectra confirm the films are composed only of Mo and O atoms. The O/Mo ratio is nearly equal to 3 that shows the stoichiometry of MoO{sub 3}.

  8. Nondestructive SEM for surface and subsurface wafer imaging

    Science.gov (United States)

    Propst, Roy H.; Bagnell, C. Robert; Cole, Edward I., Jr.; Davies, Brian G.; Dibianca, Frank A.; Johnson, Darryl G.; Oxford, William V.; Smith, Craig A.

    1987-01-01

    The scanning electron microscope (SEM) is considered as a tool for both failure analysis as well as device characterization. A survey is made of various operational SEM modes and their applicability to image processing methods on semiconductor devices.

  9. SEM OBSERVATION OF THE CRAZING FOR POLYPHENYLQUINOXALINE FILMS DURING IN SITU STRETCHING

    Institute of Scientific and Technical Information of China (English)

    Wan-jun Liu; Jing-shu Shen; Feng-cai Lu; Mao Xu

    1999-01-01

    The crazing of polyphenylquinoxaline (PPQ-E) films during in situ stretching has been observed by SEM. The crazing phenomena and craze morphology of PPQ-E films were interpreted. The strain values at critical crazing and yielding and the craze stability of PPQ-E samples depend on the thermal-dealing condition for the samples. From the point of view of cohesional entanglements and energy absorbed by samples, the experiment results were explained.

  10. The luminal surface of thyroid cysts in SEM

    DEFF Research Database (Denmark)

    Zelander, T; Kirkeby, S

    1978-01-01

    Four of the five kinds of cells constituting the walls of thyroid cysts can be identified in the SEM. These are cuboidal cells, mucous cells, cells with large granules and ciliated cells. A correlation between SEM and TEM observations is attempted.......Four of the five kinds of cells constituting the walls of thyroid cysts can be identified in the SEM. These are cuboidal cells, mucous cells, cells with large granules and ciliated cells. A correlation between SEM and TEM observations is attempted....

  11. Morphological characteristics of Barrett's esophagus under confocal laser endomicroscopy%共聚焦显微内镜下Barrett食管上皮的分布特点

    Institute of Scientific and Technical Information of China (English)

    于涛; 季锐; 李真; 李延青

    2011-01-01

    目的 探讨共聚焦显微内镜下Barrett食管(BE)上皮类型的分布特点.方法 选取胃镜检查疑诊为BE的112例患者纳入研究,对食管下段柱状上皮进行共聚焦内镜检查,实时预测BE上皮类型、判断肠上皮化生的累及范围,随后对所检查部位黏膜行活组织病理检查,分析普通内镜和共聚焦显微内镜表现与病理组织学诊断结果的关系.结果 共计94例患者被确诊为BE,普通内镜下以岛型最为常见(54.3%),短段BE比例显著高于长段BE(86.2%比13.8%),共聚焦显微内镜下可分辨特殊肠上皮化生、贲门腺和胃底腺上皮,其准确度分别为94.7%、89.4%和91.5%.靶向活组织病理检查发现长段BE中的肠上皮化生比例(9/13)高于短段BE(33.3%,x2=4.684,P=0.039),环周型和舌型BE的肠上皮化生比例(11/17和65.4%)均显著高于岛型(15.7%,x2值分别=15.217和19.399,P值均<0.01).短段BE与长段BE间,岛型、环周型和舌型BE间的肠上皮化生范围均无明显差异.结论 共聚焦显微内镜可准确分辨BE上皮的组织类型,镜下形态以岛型多见,但环周型和舌型的肠上皮化生比例更高,长段BE中的肠上皮化生比例高于短段BE.%Objective To explore the morphological characteristics of Barrett's esophagus under confocal laser endomicroscopy (CLE).Methods A total of 112 patients with suspected Barrett's esophagus (BE) under endoscopy were enrolled in this study.The lower esophageal columnar mucosa was examined with CLE to real-time forecast the histological type and extent of intestinal metaplasia of BE,followed by mucosal biopsies and histopathological examination in inspected area.The relationship between the features under common endoscopy or CLE and histopathological diagnosis was analyzed.Results A total of 94 patients were diagnosed as BE.Island type is the most common type under common endoscopy (54.3%),and the incidence of short-segment BE was higher than that of longsegment

  12. Laser surface alloying of 316L stainless steel coated with a bioactive hydroxyapatite-titanium oxide composite.

    Science.gov (United States)

    Ghaith, El-Sayed; Hodgson, Simon; Sharp, Martin

    2015-02-01

    Laser surface alloying is a powerful technique for improving the mechanical and chemical properties of engineering components. In this study, laser surface irradiation process employed in the surface modification off 316L stainless steel substrate using hydroxyapatite-titanium oxide to provide a composite ceramic layer for the suitability of applying this technology to improve the biocompatibility of medical alloys and implants. Fusion of the metal surface incorporating hydroxyapatite-titania ceramic particles using a 30 W Nd:YAG laser at different laser powers, 40, 50 and 70% power and a scan speed of 40 mm s(-1) was observed to adopt the optimum condition of ceramic deposition. Coatings were evaluated in terms of microstructure, surface morphology, composition biocompatibility using XRD, ATR-FTIR, SEM and EDS. Evaluation of the in vitro bioactivity by soaking the treated metal in SBF for 10 days showed the deposition of biomimetic apatite.

  13. Amorphous Structures in Laser Cladding of ZL111 Aluminum Alloy:Semi-quantitative Study by Differential Thermal Analysis (DTA)

    Institute of Scientific and Technical Information of China (English)

    LI Xianqin; CHENG Zhaogu; XIA Jin'an; XU Guoliang; LIANG Gongying

    2000-01-01

    This paper deals with amorphous structures in the laser cladding. ZL111 alloy is the substrate and Ni-Cr-Al alloy is sprayed on the substrate as the coating material. The coating is clad by a 5 kW transverse flow CO2 laser. The observation of SEM and TEM reveal that in the laser cladding there are amorphous structures of two different morphologies: one is space curved flake-like, and exists in the white web-like structures; the other is fir leaf-like, and exists in the grain-like structures. Differential thermal analysis (DTA) is used to semi-quantitatively determine the content of the amorphous structures. A relation is obtained between the content of amorphous structures and the dimensionless laser cladding parameter C. We also show the changes of the amorphous structures after annealing.

  14. In-situ tensile testing of propellant samples within SEM

    NARCIS (Netherlands)

    Benedetto, G.L. di; Ramshorst, M.C.J. van; Duvalois, W.; Hooijmeijer, P.A.; Heijden, A.E.D.M. van der; Klerk, W.P.C. de

    2015-01-01

    A tensile module system placed within a FEI NovaNanoSEM 650 Scanning Electron Microscope (SEM) was utilized in this work to conduct in-situ tensile testing of propellant material samples. This tensile module system allows for real-time in-situ SEM analysis of the samples to determine the failure mec

  15. Laser surface preparation for adhesive improvement of Ti6Al4V

    Science.gov (United States)

    Loumena, C.; Cherif, M.; Taleb Ali, M.; Jumel, J.; Kling, R.

    2017-02-01

    Titanium alloys are generally noticed for their high specific strength and their good corrosion resistance. They are widely used in light-weight structures especially in the aerospace industry. Surface preparation of Ti6Al4V for bonding improvement is conventionally performed by chemical, electrochemical pre-treatments (chromic acid anodizing, phosphate-fluoride, sol-gel,…) and/or sandblasting in order to modify the morphology and the chemistry of the surface. However, these processes produce a large volume of hazardous chemical or abrasive waste. They require high technical efforts and are therefore economically and environmentally inefficient. Laser processes could lead to a good alternative solution in terms of eco-compatibility, repeatability and ease of manufacturing. In this paper, we report on the latest developments of the collaboration between ALPhANOV and I2M institute on the laser surface preparation for adhesive bonding improvement of Ti6Al4V. We focus our investigations on the effect of pulsed laser irradiation (fluence, scan speed and lateral overlap) with a visible (515 nm) nanosecond "rod-type fibre" laser on the surface morphology and its bonding behaviour (cohesive or adhesive failure). The penetration of the adhesive in the roughness induced by laser irradiation was characterized. For this study, the surfaces were inspected by different means as optical microscopy, 3D profilometer and scanning electron microscopy (SEM). The adhesion performance of the laser treated surface was evaluated by means of DCB tests.

  16. Periodical structures induced by femtosecond laser on metals in air and liquid environments

    Science.gov (United States)

    Albu, Catalina; Dinescu, Adrian; Filipescu, Mihaela; Ulmeanu, Magdalena; Zamfirescu, Marian

    2013-08-01

    Ripples or laser-induced periodic surface structures (LIPSS) are obtained on metallic films (Cr, Ti, and W) by femtosecond laser pulses working at both fundamental (775 nm) and frequency doubled (387 nm) wavelengths in air and liquid environments. The metallic samples were irradiated at normal incidence, in air and by immersing them in water (H2O), ethanol (C2H5OH) or chloroform (CHCl3). Different morphologies were observed after laser irradiation on the material surface, depending on material, environments and the laser irradiation parameters. We observed areas of ripples or nanostructures (NS) at both irradiation laser wavelengths in all environments used. The morphology of the formed structures was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The analysis of images obtained revealed two kinds of ripples: low spatial frequency LIPSS (LSFL) with a periodicity from 350 to 600 nm, and high spatial frequency LIPSS (HSFL) with a periodicity from about 50 to 200 nm. We found that the periods of the structures formed in liquids are generally several times smaller than those formed in air. When samples are processed in air with 387 nm laser wavelength, the periods are similar to those obtained in liquids at 775 nm. The formation mechanisms of ripples structures are discussed.

  17. Periodical structures induced by femtosecond laser on metals in air and liquid environments

    Energy Technology Data Exchange (ETDEWEB)

    Albu, Catalina, E-mail: catalina.radu@inflpr.ro [National Institute for Laser, Plasma and Radiation Physics, Laser Department, Atomistilor Str. 409, P.O. Box MG-36, 077125 Magurele, Bucharest (Romania); Dinescu, Adrian [National Institute for Research and Development in Microtechnology, Erou Iancu Nicolae Str. 126A, 077190 Bucharest (Romania); Filipescu, Mihaela; Ulmeanu, Magdalena [National Institute for Laser, Plasma and Radiation Physics, Laser Department, Atomistilor Str. 409, P.O. Box MG-36, 077125 Magurele, Bucharest (Romania); Zamfirescu, Marian [National Institute for Laser, Plasma and Radiation Physics, Laser Department, Atomistilor Str. 409, P.O. Box MG-36, 077125 Magurele, Bucharest (Romania); National Institute for Research and Development in Microtechnology, Erou Iancu Nicolae Str. 126A, 077190 Bucharest (Romania)

    2013-08-01

    Ripples or laser-induced periodic surface structures (LIPSS) are obtained on metallic films (Cr, Ti, and W) by femtosecond laser pulses working at both fundamental (775 nm) and frequency doubled (387 nm) wavelengths in air and liquid environments. The metallic samples were irradiated at normal incidence, in air and by immersing them in water (H{sub 2}O), ethanol (C{sub 2}H{sub 5}OH) or chloroform (CHCl{sub 3}). Different morphologies were observed after laser irradiation on the material surface, depending on material, environments and the laser irradiation parameters. We observed areas of ripples or nanostructures (NS) at both irradiation laser wavelengths in all environments used. The morphology of the formed structures was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The analysis of images obtained revealed two kinds of ripples: low spatial frequency LIPSS (LSFL) with a periodicity from 350 to 600 nm, and high spatial frequency LIPSS (HSFL) with a periodicity from about 50 to 200 nm. We found that the periods of the structures formed in liquids are generally several times smaller than those formed in air. When samples are processed in air with 387 nm laser wavelength, the periods are similar to those obtained in liquids at 775 nm. The formation mechanisms of ripples structures are discussed.

  18. Semântica e lexicografia

    Directory of Open Access Journals (Sweden)

    Julio Casares

    2001-01-01

    Full Text Available

    A Semântica e a Lexicografia se interpenetram mutuamente porque a Lexicografia não se limita a recolher as palavras do léxico, mas procura descrever a significação dos vocábulos e seus usos. O lexicógrafo também se ocupa de evolução dos sentidos das palavras para estabelecer a escala das acepções de um signo lexical. Casares conceitua acepção e discute o problema da discriminação das acepções e da sua ordenação no caso de palavras polissêmicas. Outra Questão delicada para o lexicógrafo é o reconhecimento e a identificação correta dos valores metafóricos. O autor usa como exemplo ilustrativo o verbete lat. ordo > esp. orden (port. ordem, signo polissêmico. Traça gráficos da ma-, lha de significações na semântica evolutiva dessa palavra, do étimo original latino ao espanhol moderno. Casares também trata do problema da lematização, ou seja, a decisão técnica de escolher como entrada de um dicionário, uma ou outra forma vocabular, o que envolve controvérsias permanentes em meio aos lexicólogos sobre as lexias (palavras complexas e como e quando se dá a categorização lexical de um polinómio vocabular. Esse problema é ampliado por causa da tradição caótica de muitas grafias, particularmente no caso de "locuções vocabulares". Advoga as vantagens e as virtudes de um dicionário que tivesse um índice de freqüência do uso de cada palavra, ou de cada acepção de um vocábulo.

  19. Photocatalytic activity of titania coatings synthesised by a combined laser/sol–gel technique

    Energy Technology Data Exchange (ETDEWEB)

    Adraider, Y. [School of Science and Engineering, Teesside University, Middlesbrough TS1 3BA (United Kingdom); Pang, Y.X., E-mail: F6098038@tees.ac.uk [School of Science and Engineering, Teesside University, Middlesbrough TS1 3BA (United Kingdom); Nabhani, F.; Hodgson, S.N. [School of Science and Engineering, Teesside University, Middlesbrough TS1 3BA (United Kingdom); Sharp, M.C.; Al-Waidh, A. [General Engineering Research Institute, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF (United Kingdom)

    2014-06-01

    Highlights: • Sol–gel method was used to prepare titania coatings. • Titania thin films were coated on substrate surface by dip coating. • Fibre laser was employed to irradiate the titania coated surfaces. • Photocatalytic efficiency of titania coatings was significantly improved after laser processing. - Abstract: Titania coatings were prepared using sol–gel method and then applied on the substrate surface by dip coating. Fibre laser (λ = 1064 nm) in continuous wave mode was used to irradiate the titania coated surfaces at different specific energies. The ATR-FTIR, XRD, SEM, EDS and contact angle measurement were employed to analyse surface morphology, phase composition and crystalline structure of laser-irradiated titania coatings, whilst the photocatalytic activity was evaluated by measuring the decomposition of methylene blue (MB) after exposure to the visible light for various illumination times. Results showed that the laser-irradiated titania coatings demonstrate significant different composition and microstructure in comparison with the as-coated from the same sol–gel titania. Photocatalytic efficiency of titania coatings was significantly improved after laser processing. The photocatalytic activity of laser-irradiated titania coatings was higher than that of the as-coated titania. The titania coating processed at laser specific energy of 6.5 J/mm{sup 2} exhibited the highest photocatalytic activity among all titania samples.

  20. Test Technology of Explosively Formed Projectile Morphology Based on Laser Parallel Screens%激光平行光幕的爆炸成型弹丸形貌测试技术

    Institute of Scientific and Technical Information of China (English)

    王高; 尹国鑫; 田大新; 狄宋珍; 李仰军

    2012-01-01

    针对目前爆炸成型弹丸形貌测试普遍使用的脉冲X光摄影法成本昂贵、结构复杂、测试困难的缺点,提出了激光平行光幕形貌测试系统.该系统中,由启动网靶、停止网靶和计时仪组成的区截测速装置测试EFP的速度,激光平行光幕和示波器测试EFP弹丸通过光幕时直径随时间的变化过程.然后将上述测试结果用Matlab软件进行仿真,得出EFP弹丸的形貌.测试与仿真表明:激光平行光幕形貌测试系统可以测试EFP弹丸的速度与形貌,而且成本低廉、可靠性高,可以在大威力战斗部试验中使用.%At present, the pulsed X-ray method is often used to test the parameters explosively formed projectile. However this method is expensive, complex and difficult to operate. A new method is proposed which uses laser parallel screens to test the morphology of EFP. In this system, the combination of starting target, stopping target and timing device is used to test the velocity speed of EFP; laser parallel screens are used to test the diameter changes of EFP projectile; then this paper uses Matlab to simulate the above test results and obtain the morphology of EFP. The test and simulation results show that the system of laser parallel screens can be used to test the velocity and morphology of EFP. This system is low cost, high reliability, and can be used in the test of big powerful warhead exploitive.

  1. EPA Region 2 SEMS_CERCLIS Sites All [R2] and SEMS_CERCLIS Sites NPL [R2] GIS Layers

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Region 2 SEMS_CERCLIS Sites All [R2] GIS layer contains unique Superfund Enterprise Management System (SEMS) site records. These records have the following...

  2. Morphological Snakes

    OpenAIRE

    Álvarez, Luis; Baumela Molina, Luis; Henríquez, Pedro; Márquez Neila, Pablo

    2010-01-01

    We introduce a morphological approach to curve evolution. The differential operators used in the standard PDE snake models can be approached using morphological operations on a binary level set. By combining the morphological operators associated to the PDE components we achieve a new snakes evolution algorithm. This new solution is based on numerical methods which are very simple, fast and stable. Moreover, since the level set is just a binary piecewise constant function, this approach does ...

  3. Extending ultra-short pulse laser texturing over large area

    Energy Technology Data Exchange (ETDEWEB)

    Mincuzzi, G., E-mail: girolamo.mincuzzi@alphanov.com; Gemini, L.; Faucon, M.; Kling, R.

    2016-11-15

    Highlights: • We carried out metal surface texturing (Ripples, micro grooves, Spikes) using a high power, high repetition rate, industrial, Ultra-short pulses laser. • Extremely Fast processing is shown (Laser Scan speed as high as 90 m/s) with a polygon scanner head. • Stainless steel surface blackening with Ultra-short pulses laser has been obtained with unprecedented scanspeed. • Full SEM surface characterization was carried out for all the different structures obtained. • Reflectance measurements were carried out to characterize surface reflectance. - Abstract: Surface texturing by Ultra-Short Pulses Laser (UPL) for industrial applications passes through the use of both fast beam scanning systems and high repetition rate, high average power P, UPL. Nevertheless unwanted thermal effects are expected when P exceeds some tens of W. An interesting strategy for a reliable heat management would consists in texturing with a low fluence values (slightly higher than the ablation threshold) and utilising a Polygon Scanner Heads delivering laser pulses with unrepeated speed. Here we show for the first time that with relatively low fluence it is possible over stainless steel, to obtain surface texturing by utilising a 2 MHz femtosecond laser jointly with a polygonal scanner head in a relatively low fluence regime (0.11 J cm{sup −2}). Different surface textures (Ripples, micro grooves and spikes) can be obtained varying the scan speed from 90 m s{sup −1} to 25 m s{sup −1}. In particular, spikes formation process has been shown and optimised at 25 m s{sup −1} and a full morphology characterization by SEM has been carried out. Reflectance measurements with integrating sphere are presented to compare reference surface with high scan rate textures. In the best case we show a black surface with reflectance value < 5%.

  4. FIB/SEM cell sectioning for intracellular metal granules characterization

    Science.gov (United States)

    Milani, Marziale; Brundu, Claudia; Santisi, Grazia; Savoia, Claudio; Tatti, Francesco

    2009-05-01

    Focused Ion Beams (FIBs) provide a cross-sectioning tool for submicron dissection of cells and subcellular structures. In combination with Scanning Electron Microscope (SEM), FIB provides complementary morphological information, that can be further completed by EDX (Energy Dispersive X-ray Spectroscopy). This study focus onto intracellular microstructures, particularly onto metal granules (typically Zn, Cu and Fe) and on the possibility of sectioning digestive gland cells of the terrestrial isopod P. scaber making the granules available for a compositional analysis with EDX. Qualitative and quantitative analysis of metal granules size, amount and distribution are performed. Information is made available of the cellular storing pattern and, indirectly, metal metabolism. The extension to human level is of utmost interest since some pathologies of relevance are metal related. Apart from the common metal-overload-diseases (hereditary hemochromatosis, Wilson's and Menkes disease) it has been demonstrated that metal in excess can influence carcinogenesis in liver, kidney and breast. Therefore protocols will be established for the observation of mammal cells to improve our knowledge about the intracellular metal amount and distribution both in healthy cells and in those affected by primary or secondary metal overload or depletion.

  5. Automated SEM Modal Analysis Applied to the Diogenites

    Science.gov (United States)

    Bowman, L. E.; Spilde, M. N.; Papike, James J.

    1996-01-01

    Analysis of volume proportions of minerals, or modal analysis, is routinely accomplished by point counting on an optical microscope, but the process, particularly on brecciated samples such as the diogenite meteorites, is tedious and prone to error by misidentification of very small fragments, which may make up a significant volume of the sample. Precise volume percentage data can be gathered on a scanning electron microscope (SEM) utilizing digital imaging and an energy dispersive spectrometer (EDS). This form of automated phase analysis reduces error, and at the same time provides more information than could be gathered using simple point counting alone, such as particle morphology statistics and chemical analyses. We have previously studied major, minor, and trace-element chemistry of orthopyroxene from a suite of diogenites. This abstract describes the method applied to determine the modes on this same suite of meteorites and the results of that research. The modal abundances thus determined add additional information on the petrogenesis of the diogenites. In addition, low-abundance phases such as spinels were located for further analysis by this method.

  6. Assessment of root caries removal by Er,Cr:YSGG laser

    Science.gov (United States)

    Geraldo-Martins, Vinícius R.; Marques, Márcia M.

    2007-02-01

    The present study aimed to compare root caries removal by air turbine and Er,Cr:YSGG laser, and examine morphological changes after these caries removal techniques under scanning electron microscopy (SEM). Seventy two extracted human carious-free third molars were used in this study. After the in vitro root caries induction using S. mutans, the carious lesions were removed by the conventional technique, using burs (control), and by the Er,Cr:YSGG laser, using 13 different parameters, between 1 and 4,0 W. During caries removal, preparation time was recorded for all groups. The results appointed out that the conventional method was the fastest one. When only laser treatment was evaluated, the higher parameters seemed to remove caries faster then the lower ones. SEM revealed that the surfaces treated by air turbine were smooth, but with debris. The laser groups demonstrated smooth undulations, with little or absence of smear layer, and no signs of carbonization. These results suggest that caries removal by Er,Cr:YSGG laser was effective. Therefore, this equipment requires training on cavity preparation, in order to avoid damages in dental hard tissues.

  7. Investigation of the microstructure and surface morphology of a Ti6Al4V plate fabricated by vacuum selective laser melting

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Yuji; Tsukamoto, Masahiro; Masuno, Shinichiro; Abe, Nobuyuki [Osaka University, Joining and Welding Research Institute, Ibaraki, Osaka (Japan); Yamashita, Yorihiro [Industrial Research Institute of Ishikawa, Kanazawa, Ishikawa (Japan); Yamashita, Kensuke; Tanigawa, Daichi [Osaka University, Graduate School of Engineering, Suita, Osaka (Japan)

    2016-04-15

    As an additive manufacturing technology, the selective laser melting (SLM) process is useful to directly form complicated shapes. The SLM process in a vacuum has been used to fabricate three-dimensional Ti6Al4V (Ti64) plates because this method can control the phase transformation. To investigate the laser melting and solidification dynamics, the formation of a Ti64 plate by SLM in a vacuum was captured by a high-speed video camera. Due to the effects of temperature and scanning speed on the phase transformation, the crystal orientation was evaluated with X-ray diffraction. A phase transformation of the crystal orientation occurred as the baseplate temperature was heated up from 50 to 150 C. (orig.)

  8. Investigation of the microstructure and surface morphology of a Ti6Al4V plate fabricated by vacuum selective laser melting

    Science.gov (United States)

    Sato, Yuji; Tsukamoto, Masahiro; Masuno, Shinichiro; Yamashita, Yorihiro; Yamashita, Kensuke; Tanigawa, Daichi; Abe, Nobuyuki

    2016-04-01

    As an additive manufacturing technology, the selective laser melting (SLM) process is useful to directly form complicated shapes. The SLM process in a vacuum has been used to fabricate three-dimensional Ti6Al4V (Ti64) plates because this method can control the phase transformation. To investigate the laser melting and solidification dynamics, the formation of a Ti64 plate by SLM in a vacuum was captured by a high-speed video camera. Due to the effects of temperature and scanning speed on the phase transformation, the crystal orientation was evaluated with X-ray diffraction. A phase transformation of the crystal orientation occurred as the baseplate temperature was heated up from 50 to 150 °C.

  9. Analysis list: sem-4 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available sem-4 Larvae + ce10 http://dbarchive.biosciencedbc.jp/kyushu-u/ce10/target/sem-4.1....tsv http://dbarchive.biosciencedbc.jp/kyushu-u/ce10/target/sem-4.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/ce10/target/sem...-4.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/ce10/colo/sem-4.Larvae.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/ce10/colo/Larvae.gml ...

  10. Bioactive glass thin films synthesized by advanced pulsed laser techniques

    Science.gov (United States)

    Mihailescu, N.; Stan, George E.; Ristoscu, C.; Sopronyi, M.; Mihailescu, Ion N.

    2016-10-01

    Bioactive materials play an increasingly important role in the biomaterials industry, and are extensively used in a range of applications, including biodegradable metallic implants. We report on Bioactive Glasses (BG) films deposition by pulsed laser techniques onto biodegradable substrates. The BG coatings were obtained using a KrF* excimer laser source (λ= 248 nm, τFWHM ≤ 25 ns).Their thickness has been determined by Profilometry measurements, whilst their morphology has been analysed by Scanning Electron Microscopy (SEM). The obtained coatings fairly preserved the targets composition and structure, as revealed by Energy Dispersive X-Ray Spectroscopy, Grazing Incidence X-Ray Diffraction, and Fourier Transform Infra-Red Spectroscopy analyses.

  11. Morphological aspects and Cox-2 expression after exposure to 780-nm laser therapy in injured skeletal muscle: an in vivo study

    Science.gov (United States)

    Rodrigues, Natalia C.; Brunelli, Roberta; Abreu, Daniela C. C.; Fernandes, Kelly; Parizotto, Nivaldo A.; Renno, Ana C. M.

    2014-01-01

    Background: The effectiveness of low-level laser therapy in muscle regeneration is still not well known. Objective: To investigate the effects of laser irradiation during muscle healing. Method: For this purpose, 63 rats were distributed to 3 groups: non-irradiated control group (CG); group irradiated at 10 J/cm² (G10); and group irradiated at 50 J/cm² (G50). Each group was divided into 3 different subgroups (n=7), and on days 7, 14 and 21 post-injury the rats were sacrificed. Results: Seven days post-surgery, the CG showed destroyed zones and extensive myofibrillar degeneration. For both treated groups, the necrosis area was smaller compared to the CG. On day 14 post-injury, treated groups demonstrated better tissue organization, with newly formed muscle fibers compared to the CG. On the 21st day, the irradiated groups showed similar patterns of tissue repair, with improved muscle structure at the site of the injury, resembling uninjured muscle tissue organization. Regarding collagen deposition, the G10 showed an increase in collagen synthesis. In the last period evaluated, both treated groups showed statistically higher values in comparison with the CG. Furthermore, laser irradiation at 10 J/cm2 produced a down-regulation of cyclooxygenase 2 (Cox-2) immunoexpression on day 7 post-injury. Moreover, Cox-2 immunoexpression was decreased in both treated groups on day 14. Conclusions: Laser therapy at both fluencies stimulated muscle repair through the formation of new muscle fiber, increase in collagen synthesis, and down-regulation of Cox-2 expression. PMID:25372001

  12. Morphological aspects and Cox-2 expression after exposure to 780-nm laser therapy in injured skeletal muscle: an in vivo study

    Directory of Open Access Journals (Sweden)

    Natalia C. Rodrigues

    2014-10-01

    Full Text Available Background: The effectiveness of low-level laser therapy in muscle regeneration is still not well known. Objective: To investigate the effects of laser irradiation during muscle healing. Method: For this purpose, 63 rats were distributed to 3 groups: non-irradiated control group (CG; group irradiated at 10 J/cm² (G10; and group irradiated at 50 J/cm² (G50. Each group was divided into 3 different subgroups (n=7, and on days 7, 14 and 21 post-injury the rats were sacrificed. Results: Seven days post-surgery, the CG showed destroyed zones and extensive myofibrillar degeneration. For both treated groups, the necrosis area was smaller compared to the CG. On day 14 post-injury, treated groups demonstrated better tissue organization, with newly formed muscle fibers compared to the CG. On the 21st day, the irradiated groups showed similar patterns of tissue repair, with improved muscle structure at the site of the injury, resembling uninjured muscle tissue organization. Regarding collagen deposition, the G10 showed an increase in collagen synthesis. In the last period evaluated, both treated groups showed statistically higher values in comparison with the CG. Furthermore, laser irradiation at 10 J/cm2 produced a down-regulation of cyclooxygenase 2 (Cox-2 immunoexpression on day 7 post-injury. Moreover, Cox-2 immunoexpression was decreased in both treated groups on day 14. Conclusions: Laser therapy at both fluencies stimulated muscle repair through the formation of new muscle fiber, increase in collagen synthesis, and down-regulation of Cox-2 expression.

  13. Adjusting island density and morphology of the SrTiO3(110)-(4 × 1) surface: Pulsed laser deposition combined with scanning tunneling microscopy

    Science.gov (United States)

    Gerhold, Stefan; Riva, Michele; Yildiz, Bilge; Schmid, Michael; Diebold, Ulrike

    2016-09-01

    The first stages of homoepitaxial growth of the (4 × 1) reconstructed surface of SrTiO3(110) are probed by a combination of pulsed laser deposition (PLD) with in-situ reflection high energy electron diffraction (RHEED) and scanning tunneling microscopy (STM). Considerations of interfacing high-pressure PLD growth with ultra-high-vacuum surface characterization methods are discussed, and the experimental setup and procedures are described in detail. The relation between RHEED intensity oscillations and ideal layer-by-layer growth is confirmed by analysis of STM images acquired after deposition of sub-monolayer amounts of SrTiO3. For a quantitative agreement between RHEED and STM results one has to take into account two interfaces: the steps at the circumference of islands, as well as the borders between two different reconstruction phases on the islands themselves. Analysis of STM images acquired after one single laser shot reveals an exponential decrease of the island density with increasing substrate temperature. This behavior is also directly visible from the temperature dependence of the relaxation times of the RHEED intensity. Moreover, the aspect ratio of islands changes considerably with temperature. The growth mode depends on the laser pulse repetition rate, and can be tuned from predominantly layer-by-layer to the step-flow growth regime.

  14. Nd:YAG laser annealing investigation of screen-printed CIGS layer on PET: Layer annealing method for photovoltaic cell fabrication process

    KAUST Repository

    Alsaggaf, Ahmed

    2014-06-01

    Cu(In, Ga)Se2 (CIGS) ink was formulated from CIGS powder, polyvinyl butyral PVB, terpineol and polyester/polyamine co-polymeric dispersant KD-1. Thin films with different thicknesses were deposited on PET substrate using screen-printing followed by heat treatment using a Nd:YAG laser. The structure and morphology of the heated thin films were studied. The characterization of the CIGS powder, ink, and film was done using TGA, SEM, FIB, EDS, and XRD. TGA analysis shows that the CIGS ink is drying at 200 °C, which is well below the decomposition temperature of the PET substrate. It was observed by SEM that 20 pulses of 532nm and 60 mJ/cm2 Nd:YAG laser annealing causes atomic diffusion on the near surface area. Furthermore, FIB cross section images were utilized to monitor the effect of laser annealing in the depth of the layer. Laser annealing effects were compared to as deposited layer using XRD in reference to CIGS powder. The measurement shows that crystallinity of deposited CIGS is retained while EDS quantification and atomic ratio result in gradual loss of selenium as laser energy increases. The laser parameters were tuned in an effort to utilize laser annealing of screen-printed CIGS layer as a layer annealing method for solar cell fabrication process.

  15. Group morphology

    NARCIS (Netherlands)

    Roerdink, Jos B.T.M.

    2000-01-01

    In its original form, mathematical morphology is a theory of binary image transformations which are invariant under the group of Euclidean translations. This paper surveys and extends constructions of morphological operators which are invariant under a more general group TT, such as the motion group

  16. Synthesis of carbon nanotubes by laser ablation in graphite substrate of industrial arc electrodes

    Science.gov (United States)

    Guerrero, A.; Puerta, J.; Gomez, F.; Blanco, F.

    2008-10-01

    In this work, an inexpensive and simple technique for the synthesis of carbon nanotubes (CNTs) by using graphite as the target for IR laser radiation is presented. This graphite material is obtained from the recycled graphite electrode core of an electric arc furnace. The experiment was carried out in a reaction chamber in an argon atmosphere at a low pressure. For laser ablation, a Lumonics TEA CO2 laser beam (7 J; 0.05-50 μs pulse length) was used in multimode operation. Products were collected on free mica sheets. The substrates were characterized by scanning electron microscopy (SEM) and the products were characterized (collected as powder) by transmission electron microscopy (TEM). They showed significant amounts of high-quality dense filaments (CNTs) that were morphologically not aligned.

  17. A novel method for preparing the antibacterial glass fibre mat using laser treatment

    Science.gov (United States)

    Wiener, Jakub; Shahidi, Sheila; Mkhululi Goba, Makabongwe; Šašková, Jana

    2014-02-01

    In this study, CO2 laser treatment was used as a novel method for creating antibacterial properties on glass mat. Different metallic salts such as CuO, ZnO and AgNO3 were even applied on surface of glass fiber mat, then irradiated with the laser light beam (100 μs). Metal particles were deposited on the surface of samples, and the antibacterial has been developed, through incorporation of metal particles on glass mats. The antibacterial properties of the fabrics were connected with the presence of metal particles on their surface. The amounts of metal particles on the surface were compared using X-ray fluorescence (XRF) and energy dispersive X-ray spectrometer (EDS). Also the morphological properties of the fabrics were observed using a scanning electron microscope (SEM). The experimental work suggests that the change in properties induced by laser can effect an improvement in certain textile products.

  18. Laser reflection spot as a pattern in a diamond coating – a microscopic study

    Directory of Open Access Journals (Sweden)

    GORDANA S. RISTIĆ

    2009-07-01

    Full Text Available Diamond coatings were deposited by the synchronous and coupled action of a hot filament CVD method and a pulsed CO2 laser in spectro-absorbing and spectro-non-absorbing diamond precursor atmospheres. The obtained coatings were structured/patterned, i.e., they were comprised of uncovered, bare locations. An extra effect observed only in the spectro-active diamond precursor atmosphere was the creation of another laser spot in the coating – a reflection spot. In order to establish the practical usability of the latter one, extensive microscopic investigations were performed with consideration of the morphology changes in the spot of the direct laser beam. Normal incidence SEM images of this spot showed a smooth surface, without any pulse radiation damage. AFM imaging revealed the actual surface condition and gave precise data on the surface characteristics.

  19. Influence of wavelength on the laser removal of lichens colonizing heritage stone

    Science.gov (United States)

    Sanz, M.; Oujja, M.; Ascaso, C.; Pérez-Ortega, S.; Souza-Egipsy, V.; Fort, R.; de los Rios, A.; Wierzchos, J.; Cañamares, M. V.; Castillejo, M.

    2017-03-01

    Laser irradiation of lichen thalli on heritage stones serves for the control of epilithic and endolithic biological colonizations. In this work we investigate rock samples from two quarries traditionally used as source of monumental stone, sandstone from Valonsadero (Soria, Spain) and granite from Alpedrete (Madrid, Spain), in order to find conditions for efficient laser removal of lichen thalli that ensure preservation of the lithic substrate. The samples presented superficial areas colonized by different types of crustose lichens, i.e. Candelariella vitellina, Aspicilia viridescens, Rhizocarpon disporum and Protoparmeliopsis muralis in Valonsadero samples and P. cf. bolcana and A. cf. contorta in Alpedrete samples. A comparative laser cleaning study was carried out on the mentioned samples with ns Q-switched Nd:YAG laser pulses of 1064 nm (fundamental radiation), 355 nm (3rd harmonic) and 266 nm (4th harmonic) and sequences of IR-UV pulses. A number of techniques such as UV-Vis absorption spectroscopy, stereomicroscopy, scanning electron microscopy (SEM) at low vacuum, SEM with backscattered electron imaging (SEM-BSE), electron dispersive spectroscopy (EDS) and FT-Raman spectroscopy were employed to determine the best laser irradiation conditions and to detect possible structural, morphological and chemical changes on the irradiated surfaces. The results show that the laser treatment does not lead to the complete removal of the studied lichen thalli, although clearly induces substantial damage, in the form of loss of the lichen upper cortex and damage to the algal layer. In the medium term these alterations could result in the destruction of the lichen thalli, thus providing a degree of control of the biodeterioration processes of the lithic substrate and reducing the chances of subsequent lichen recolonization.

  20. Morphologlcal and anatomical structure of generative organs of Salsola kali ssp. ruthenica (lljin Soó at the SEM level

    Directory of Open Access Journals (Sweden)

    Krystyna Idzikowska

    2011-01-01

    Full Text Available The morphology and anatomy of generative organs of Salsola kali ssp. ruthenica was examined in detail using the light (LM and scanning electron microscopy (SEM. The whole flowers, fruits and their parts (pistil, stamens, sepals, embryo, seed were observed in different developmental stages. In the first stage (June, flower buds were closed. In the second stage (August, flowers were ready for pollination/fertilization. In the third stage (September, fruits were mature. Additionally, the anatomical and morphological structure of sepals was observed by means of LM and SEM. Thanks to the transverse and longitudinal semi-sections through sepals, the first phase of wing formation was recorded by SEM. The appearance of stomata in the epidermal cells of sepals above the forming wings was very interesting, too. The stomata were observed also in mature fruits.

  1. Pulsed laser ablation of Germanium under vacuum and hydrogen environments at various fluences

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Hassan [Centre for Advanced Studies in Physics, Government College University, Lahore (Pakistan); Bashir, Shazia, E-mail: shaziabashir@gcu.edu.pk [Centre for Advanced Studies in Physics, Government College University, Lahore (Pakistan); Rafique, Muhammad Shahid [Department of Physics, University of Engineering and Technology, Lahore (Pakistan); Dawood, Asadullah; Akram, Mahreen; Mahmood, Khaliq; Hayat, Asma; Ahmad, Riaz; Hussain, Tousif [Centre for Advanced Studies in Physics, Government College University, Lahore (Pakistan); Mahmood, Arshad [National Institute of Laser and Optronics (NILOP), Islamabad (Pakistan)

    2015-07-30

    Highlights: • Germanium targets were exposed under vacuum and H{sub 2} environment by nanosecond laser pulses. • The effect of laser fluence and ambient environment has been investigated. • The surface morphology is investigated by SEM analysis. • Raman and FTIR Spectroscopy are performed to reveal structural modification. • Electrical conductivity is probed by four probe method. - Abstract: Laser fluence and ambient environment play a significant role for the formation and development of the micro/nano-structures on the laser irradiated targets. Single crystal (1 0 0) Germanium (Ge) has been ablated under two environments of vacuum (10{sup −3} Torr) and hydrogen (100 Torr) at various fluences ranging from 4.5 J cm{sup −2} to 6 J cm{sup −2}. For this purpose KrF Excimer laser with wavelength of 248 nm, pulse duration of 18 ns and repetition rate of 20 Hz has been employed. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets was explored by Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy. Electrical conductivity of the irradiated Ge is measured by four probe method. SEM analysis exhibits the formation of laser-induced periodic surface structures (LIPSS), cones and micro-bumps in both ambient environments (vacuum and hydrogen). The formation as well as development of these structures is strongly dependent upon the laser fluence and environmental conditions. The periodicity of LIPSS or ripples varies from 38 μm to 60 μm in case of vacuum whereas in case of hydrogen environment, the periodicity varies from 20 μm to 45 μm. The difference in number of ripples and periodicity as well as in shape and size of cones and bumps in vacuum and hydrogen is explained on the basis of confinement and shielding effect of plasma. FTIR spectroscopy reveals that no new bands are formed for laser ablated Ge under vacuum, whereas C−H stretching vibration band is

  2. The pollen of No. 5 , No. 27 and No. 35 of clones of Carya illinoensis was chosen as the experimental material to study the pollen viability and pollen morphology with SEM in different processing modes, plucking time and powder numbers. The results indica%3个薄壳山核桃无性系花粉活力与显微结构比较研究

    Institute of Scientific and Technical Information of China (English)

    李川; 辜夕容; 姚小华; 王开良; 常君; 余裕龙

    2012-01-01

    The pollen of No. 5 , No. 27 and No. 35 of clones of Carya illinoensis was chosen as the experimental material to study the pollen viability and pollen morphology with SEM in different processing modes, plucking time and powder numbers. The results indicated that there are significant differences in the pollen viability in different processing modes, plucking time and powder numbers, also in the Polar axis and equatorial axis of the pollen of these three clones. The form of pollen is ellipsoid and has three apertures which are evenly disposed on the equatorial plane. The equatorial plane of the pollen of these three clones is oval in shape, while the polar planes of clones No. 5 and No. 27 are nearly round and that of No. 35 nearly triangular. There are indifferent granular veins on the surface of the pollen with granular risings equally distributed. This paper provides palynology basis for the origin, evolution and phylogenetic relationship of Carya illinoensis, and foundation of the selection and breeding of new varieties, and cross-hybrid breeding.%以薄壳山核桃无性系5号、27号、35号花粉为试验材料,测定了不同处理方式、不同采摘时期和不同出粉次数下的花粉活力,同时利用扫描电子显微镜对其花粉形态进行了观测.结果表明,不同处理方式、不同采摘时间和不同出粉次数下收集的同一薄壳山核桃无性系花粉,其活力存在显著性差异(P<0.05).3个无性系花粉极轴长(P)和赤道轴长(E)存在显著性差异(P<0.05),花粉粒形状均为扁球形,具有3个萌发孔,均匀分布在赤道面上;3个无性系花粉赤道面观均呈椭圆形,无性系5号和27号极面观呈近圆形,而无性系35号极面观呈近三角形;3个无性系花粉表面呈颗粒状纹饰,均匀分布着颗粒状的突起,表面纹饰差异不明显.通过研究薄壳山核桃花粉的超显微结构,可为薄壳山核桃品种的起源、演化以及种类间亲缘关系等提供孢粉

  3. Application of a Low-Level Laser Therapy and the Purified Protein from Natural Latex (Hevea brasiliensis in the Controlled Crush Injury of the Sciatic Nerve of Rats: A Morphological, Quantitative, and Ultrastructural Study

    Directory of Open Access Journals (Sweden)

    Fernando José Dias

    2013-01-01

    Full Text Available This study analyzed the effects of a low-level laser therapy (LLLT, 15 J/cm2, 780 nm wavelength and the natural latex protein (P1, 0.1% in sciatic nerve after crush injury (15 Kgf, axonotmesis in rats. Sixty rats (male, 250 g were allocated into the 6 groups (n=10: CG—control group; EG—nerve exposed; IG—injured nerve without treatment; LG—crushed nerve treated with LLLT; PG—injured nerve treated with P1; and LPG—injured nerve treated with LLLT and P1. After 4 or 8 weeks, the nerve samples were processed for morphological, histological quantification and ultrastructural analysis. After 4 weeks, the myelin density and morphological characteristics improved in groups LG, PG, and LPG compared to IG. After 8 weeks, PG, and LPG were similar to CG and the capillary density was higher in the LG, PG, and LPG. In the ultrastructural analysis the PG and LPG had characteristics that were similar to the CG. The application of LLLT and/or P1 improved the recovery from the nerve crush injury, and in the long term, the P1 protein was the better treatment used, since only the application of LLLT has not reached the same results, and these treatments applied together did not potentiate the recovery.

  4. BIB-SEM of representative area clay structures paving towards an alternative model of porosity

    Science.gov (United States)

    Desbois, G.; Urai, J. L.; Houben, M.; Hemes, S.; Klaver, J.

    2012-04-01

    A major contribution to understanding the sealing capacity, coupled flow, capillary processes and associated deformation in clay-rich geomaterials is based on detailed investigation of the rock microstructures. However, the direct characterization of pores in representative elementary area (REA) and below µm-scale resolution remains challenging. To investigate directly the mm- to nm-scale porosity, SEM is certainly the most direct approach, but it is limited by the poor quality of the investigated surfaces. The recent development of ion milling tools (BIB and FIB; Desbois et al, 2009, 2011; Heath et al., 2011; Keller et al., 2011) and cryo-SEM allows respectively producing exceptional high quality polished cross-sections suitable for high resolution porosity SEM-imaging at nm-scale and investigating samples under wet conditions by cryogenic stabilization. This contribution focuses mainly on the SEM description of pore microstructures in 2D BIB-polished cross-sections of Boom (Mol site, Belgium) and Opalinus (Mont Terri, Switzerland) clays down to the SEM resolution. Pores detected in images are statistically analyzed to perform porosity quantification in REA. On the one hand, BIB-SEM results allow retrieving MIP measurements obtained from larger sample volumes. On the other hand, the BIB-SEM approach allows characterizing porosity-homogeneous and -predictable islands, which form the elementary components of an alternative concept of porosity/permeability model based on pore microstructures. Desbois G., Urai J.L. and Kukla P.A. (2009) Morphology of the pore space in claystones - evidence from BIB/FIB ion beam sectioning and cryo-SEM observations. E-Earth, 4, 15-22. Desbois G., Urai J.L., Kukla P.A., Konstanty J. and Baerle C. (2011). High-resolution 3D fabric and porosity model in a tight gas sandstone reservoir: a new approach to investigate microstructures from mm- to nm-scale combining argon beam cross-sectioning and SEM imaging . Journal of Petroleum Science

  5. Mathematical morphology

    CERN Document Server

    Najman, Laurent

    2013-01-01

    Mathematical Morphology allows for the analysis and processing of geometrical structures using techniques based on the fields of set theory, lattice theory, topology, and random functions. It is the basis of morphological image processing, and finds applications in fields including digital image processing (DSP), as well as areas for graphs, surface meshes, solids, and other spatial structures. This book presents an up-to-date treatment of mathematical morphology, based on the three pillars that made it an important field of theoretical work and practical application: a solid theoretical foun

  6. Effect of LASER Irradiation on the Shear Bond Strength of Zirconia Ceramic Surface to Dentin

    Directory of Open Access Journals (Sweden)

    Sima Shahabi

    2012-09-01

    Full Text Available Background and Aims: Reliable bonding between tooth substrate and zirconia-based ceramic restorations is always of great importance. The laser might be useful for treatment of ceramic surfaces. The aim of the present study was to investigate the effect of laser irradiation on the shear bond strength of zirconia ceramic surface to dentin. Materials and Methods: In this experimental in vitro study, 40 Cercon zirconia ceramic blocks were fabricated. The surface treatment was performed using sandblasting with 50-micrometer Al2O3, CO2 laser, or Nd:YAG laser in each test groups. After that, the specimens were cemented to human dentin with resin cement. The shear bond strength of ceramics to dentin was determined and failure mode of each specimen was analyzed by stereo-microscope and SEM investigations. The data were statistically analyzed by one-way analysis of variance and Tukey multiple comparisons. The surface morphology of one specimen from each group was investigated under SEM. Results: The mean shear bond strength of zirconia ceramic to dentin was 7.79±3.03, 9.85±4.69, 14.92±4.48 MPa for CO2 irradiated, Nd:YAG irradiated, and sandblasted specimens, respectively. Significant differences were noted between CO2 (P=0.001 and Nd:YAG laser (P=0.017 irradiated specimens with sandblasted specimens. No significant differences were observed between two laser methods (P=0.47. The mode of bond failure was predominantly adhesive in test groups (CO2 irradiated specimens: 75%, Nd:YAG irradiated: 66.7%, and sandblasting: 41.7%. Conclusion: Under the limitations of the present study, surface treatment of zirconia ceramics using CO2 and Nd:YAG lasers was not able to produce adequate bond strength with dentin surfaces in comparison to sandblasting technique. Therefore, the use of lasers with the mentioned parameters may not be recommended for the surface treatment of Cercon ceramics.

  7. Morphological analysis of second-intention wound healing in rats submitted to 16 J/cm 2 λ 660-nm laser irradiation

    Directory of Open Access Journals (Sweden)

    Gonzaga Ribeiro Maria

    2009-01-01

    Full Text Available Background and Objectives : Low-level laser therapy (LLLT has been extensively applied to improve wound healing due to some biostimulatory properties presented by laser arrays apparently able to accelerate the cicatricial repair of soft tissue injuries. However, many controversial results have been reported in the literature, probably as a result of the wide sort of different protocols of photobiomodulation employed in those experiments. The goal of this study was to investigate the effect of a low-dose protocol of LLT on the intensity of the inflammatory response and the pattern of collagen fibers′ deposition during second-intention wound healing in rodents. Materials and Methods : Standard-sized wounds were carried out in the back of 24 male rats. Half of them underwent LLLT treatment (16 J/cm 2 at 660 nm delivered for 7 days. Eight and 14 days after the wounds were performed, the repairing area was removed and stained in HE and Masson′s trichrome, and the inflammatory response, epithelization, and collagen fiber depositions were evaluated. Results : We found that LLLT was able to slightly reduce the intensity of the inflammatory reaction as well as to enhance substantially the epithelization process at both 8 th and 14 th days. In addition, it also appeared to stimulate the deposition of collagen fibers at the final stages of wound healing. Conclusions : The LLLT protocol tested in this study resulted in some improvements in second-intention wound healing in rodents.

  8. Meriderma species (Myxomycetes from the Polish Carpathians: a taxonomic revision using SEM-visualized spore ornamentation

    Directory of Open Access Journals (Sweden)

    Paulina Janik

    2016-04-01

    Full Text Available Meriderma represents a recently described genus of nivicolous myxomycetes with high morphological variability. Due to many complications in its taxonomy and species recognition in the past, the group was considered a morphologically variable complex. Recent clarifications and recognition of morphological boundaries into species and morphotypes has fostered a classification revision of specimens found in the Carpathians. Material used in this study was systematically collected in the Polish part of the Carpathians from 2004 to 2009. As a result of micro- and macroscopic observations of 54 collections, we recorded nine taxa of Meriderma. Seven of these (all but M. carestiae and M. cribrarioides are the first records for Poland and for the Carpathians overall. Our observations based on analysis of spore ornamentation by SEM are in accordance with recently proposed classification and confirm segregation of taxa based on spore ornamentation pattern.

  9. Canticum Novum: música sem palavras e palavras sem som no pensamento de Santo Agostinho

    Directory of Open Access Journals (Sweden)

    Lorenzo Mammì

    2000-04-01

    Full Text Available NO De Magistro, Santo Agostinho coloca a reza e o canto numa posição similar, à margem das funções imediatamente comunicativas da linguagem. A reflexão agostiniana sobre a reza se baseia nos hábitos cristãos da leitura, da oração e da meditação silenciosas. Há sobre o canto, na prática igualmente inovadora do jubilus, melodia sem palavra destinada aos momentos mais intensos e gaudiosos da liturgia. A oração silenciosa e o jubilus são temas recorrentes da literatura patrística, mas Agostinho os aborda de maneira original, desenhando, a partir das palavras sem som da oração e do som sem palavra do jubilus, o perfil de um discurso interior, que não se destina aos homens, mas a Deus.IN HIS De Magistro Saint Augustine places prayer and song on a similar level, alongside the language immediately communicative functions. His considerations on prayer are grounded on the Christian habits of silent reading, prayer and meditation; those on song, on the equally innovating practice called jubilus, which is melody without words designed for the intensest and most joyous liturgical moments. Silent prayer and jubilus are recurring topics in patristic literature, but Augustine deals with them in an original way, drawing from the soundless words of prayer and the wordless sound of jubilus an inner discourse, addressed not to men but to God.

  10. The effects of laser repetition rate on femtosecond laser ablation of dry bone: a thermal and LIBS study.

    Science.gov (United States)

    Gill, Ruby K; Smith, Zachary J; Lee, Changwon; Wachsmann-Hogiu, Sebastian

    2016-01-01

    The aim of this study is to understand the effect of varying laser repetition rate on thermal energy accumulation and dissipation as well as femtosecond Laser Induced Breakdown Spectroscopy (fsLIBS) signals, which may help create the framework for clinical translation of femtosecond lasers for surgical procedures. We study the effect of repetition rates on ablation widths, sample temperature, and LIBS signal of bone. SEM images were acquired to quantify the morphology of the ablated volume and fsLIBS was performed to characterize changes in signal intensity and background. We also report for the first time experimentally measured temperature distributions of bone irradiated with femtosecond lasers at repetition rates below and above carbonization conditions. While high repetition rates would allow for faster cutting, heat accumulation exceeds heat dissipation and results in carbonization of the sample. At repetition rates where carbonization occurs, the sample temperature increases to a level that is well above the threshold for irreversible cellular damage. These results highlight the importance of the need for careful selection of the repetition rate for a femtosecond laser surgery procedure to minimize the extent of thermal damage to surrounding tissues and prevent misclassification of tissue by fsLIBS analysis.

  11. Observation of interactions between hydrophilic ionic liquid and water on wet agar gels by FE-SEM and its mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Chisato; Shirai, Takashi [Ceramics Research Laboratory, Nagoya Institute of Technology, 3-101-1, Honmachi, Tajimi, Gifu 507-0033 (Japan); Fuji, Masayoshi, E-mail: fuji@nitech.ac.jp [Ceramics Research Laboratory, Nagoya Institute of Technology, 3-101-1, Honmachi, Tajimi, Gifu 507-0033 (Japan)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer The mechanism of SEM observation of agar gel using ionic liquid was investigated. Black-Right-Pointing-Pointer Weak hydrogen bond between ionic liquid and water exist even under vacuum condition. Black-Right-Pointing-Pointer Ionic liquid binding ability with water is useful for observing wet material using FE-SEM. Black-Right-Pointing-Pointer We could optimize the water concentrations of sample of IL and wet material mixtures. Black-Right-Pointing-Pointer SEM observation of fine morphology of agar gel in optimum water content. - Abstract: In the present study, an attempt is made to understand the mechanism of field emission electron microscopy (FE-SEM) observation of wet agar gel using a typical hydrophilic ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate; [BMIM][BF{sub 4}]. The IL interaction with water molecules within agar gel during sample preparation condition for FE-SEM observation was investigated using Raman spectroscopy. Results showed that water molecules within agar gel form weak hydrogen bond such as BF{sub 4}{sup -} Midline-Horizontal-Ellipsis HOH Midline-Horizontal-Ellipsis BF{sub 4}{sup -} by interaction with BF{sub 4}{sup -} of IL, and, it remained stable even under vacuum condition at 60 Degree-Sign C, 24 h. This interaction was found to be helpful for IL displacement of the water molecules within agar gel. From this study, it was found that the exact morphology of gel materials in FE-SEM condition can be observed by optimization of water concentrations of IL and gel mixtures. Thus, using IL, agar gel or any other material under wet condition can be observed without drying in FE-SEM chamber, and, present result gives an insight to the mechanism of FE-SEM observation of agar gel using IL without any conducting coating.

  12. Rapid evaluation of particle properties using inverse SEM simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bekar, Kursat B [ORNL; Miller, Thomas Martin [ORNL; Patton, Bruce W [ORNL; Weber, Charles F [ORNL

    2017-01-01

    The characteristic X-rays produced by the interactions of the electron beam with the sample in a scanning electron microscope (SEM) are usually captured with a variable-energy detector, a process termed energy dispersive spectrometry (EDS). The purpose of this work is to exploit inverse simulations of SEM-EDS spectra to enable rapid determination of sample properties, particularly elemental composition. This is accomplished using penORNL, a modified version of PENELOPE, and a modified version of the traditional Levenberg Marquardt nonlinear optimization algorithm, which together is referred to as MOZAIK-SEM. The overall conclusion of this work is that MOZAIK-SEM is a promising method for performing inverse analysis of X-ray spectra generated within a SEM. As this methodology exists now, MOZAIK-SEM has been shown to calculate the elemental composition of an unknown sample within a few percent of the actual composition.

  13. Effect of the lasers used in periodontal therapy on the surfaces of restorative materials.

    Science.gov (United States)

    Hatipoğlu, Mükerrem; Barutcigil, Çağatay; Harorlı, Osman Tolga; Ulug, Bülent

    2016-05-01

    The present study aimed to reveal potential damage of the lasers, which are used as an alternative to manual instruments in periodontal therapy, might cause to the surface of restorative materials. Four different restorative materials were used: a glass-ionomer cement (GIC), a flowable composite (FC), a universal composite (UC) and an amalgam. Ten cylindrical samples (8 mm × 2 mm) were prepared for each restorative material. Two laser systems were used in subgingival curettage mode; an 940 nm diode laser (Epic Biolase, Irvine, CA) and an Er,Cr:YSGG laser (Waterlase iPlus, Biolase, Irvine, CA). After laser irradiation, roughness of the sample surfaces was measured using a profilometer. Additionally, atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses were performed to evaluate the morphology and surface deformations of the restorative materials and surfaces. The laser irradiation did not affect the surface roughness of any restorative materials relative to that of the control group (p > 0.05) except for the Er,Cr:YSGG treatment on GIC (p surface roughness tests. Within the limitations of the present study, it was demonstrated that Er,Cr:YSGG and diode lasers, aside from the Er;Cr:YSGG treatment on GIC, caused no harmful surface effects on adjacent restorative materials. SCANNING 38:227-233, 2016. © 2015 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

  14. Evaluation of Five Different Desensitizers: A Comparative Dentin Permeability and SEM Investigation In Vitro.

    Science.gov (United States)

    Yilmaz, Nasibe Aycan; Ertas, Ertan; Orucoğlu, Hasan

    2017-01-01

    The purpose of this study was to evaluate the efficacy and durability of five different dentin desensitizers (Gluma Desensitizer Powergel, Bifluorid 12, Gluma Self Etch Bond, D/Sense Crystal, Nupro Sensodyne Prophylaxis Paste with Novamin) on tubule occlusion and dentin permeability reduction in vitro. The quantitative changes in permeability of 100 dentin discs were measured after desensitizer treatments and following post-treatments of 6% citric acid challenge for 1 min or immersion in artificial saliva for 24 hours under hydrostatic pressure generated by a computerised fluid filtration meter. Qualitative SEM analyses were also carried out. Dentin permeability decreased after desensitizer application in all groups. Nevertheless, only the difference between 'Gluma Self Etch Bond' and 'Nupro Sensodyne Prophylaxis Paste with Novamin' groups was significantly different (p0.05). Of all the artificial saliva-subgroups, only the difference between 'D/Sense Crystal' and 'Bifluorid 12' was significantly different (p<0.05). In SEM analysis, morphological changes were detected on the dentin surface and within the tubules following desensitizer treatments and post-treatments. All the desensitizers significantly reduced dentin permeability by changing the morphology of the dentin surface and/or dentinal tubules. Following post-treatments, there was some reduction in the efficacy of the desensitizers which was represented by the reduction in permeability values. SEM analysis revealed some physical changes in the dentin structure which can partly give an explanation to the reduced efficacy of tested desensitizers.

  15. SEM-induced shrinkage and site-selective modification of single-crystal silicon nanopores

    Science.gov (United States)

    Chen, Qi; Wang, Yifan; Deng, Tao; Liu, Zewen

    2017-07-01

    Solid-state nanopores with feature sizes around 5 nm play a critical role in bio-sensing fields, especially in single molecule detection and sequencing of DNA, RNA and proteins. In this paper we present a systematic study on shrinkage and site-selective modification of single-crystal silicon nanopores with a conventional scanning electron microscope (SEM). Square nanopores with measurable sizes as small as 8 nm × 8 nm and rectangle nanopores with feature sizes (the smaller one between length and width) down to 5 nm have been obtained, using the SEM-induced shrinkage technique. The analysis of energy dispersive x-ray spectroscopy and the recovery of the pore size and morphology reveal that the grown material along with the edge of the nanopore is the result of deposition of hydrocarbon compounds, without structural damage during the shrinking process. A simplified model for pore shrinkage has been developed based on observation of the cross-sectional morphology of the shrunk nanopore. The main factors impacting on the task of controllably shrinking the nanopores, such as the accelerating voltage, spot size, scanned area of e-beam, and the initial pore size have been discussed. It is found that single-crystal silicon nanopores shrink linearly with time under localized irradiation by SEM e-beam in all cases, and the pore shrinkage rate is inversely proportional to the initial equivalent diameter of the pore under the same e-beam conditions.

  16. Antibacterial properties of laser spinning glass nanofibers.

    Science.gov (United States)

    Echezarreta-López, M M; De Miguel, T; Quintero, F; Pou, J; Landin, M

    2014-12-30

    A laser-spinning technique has been used to produce amorphous, dense and flexible glass nanofibers of two different compositions with potential utility as reinforcement materials in composites, fillers in bone defects or scaffolds (3D structures) for tissue engineering. Morphological and microstructural analyses have been carried out using SEM-EDX, ATR-FTIR and TEM. Bioactivity studies allow the nanofibers with high proportion in SiO2 (S18/12) to be classified as a bioinert glass and the nanofibers with high proportion of calcium (ICIE16) as a bioactive glass. The cell viability tests (MTT) show high biocompatibility of the laser spinning glass nanofibers. Results from the antibacterial activity study carried out using dynamic conditions revealed that the bioactive glass nanofibers show a dose-dependent bactericidal effect on Sthaphylococcus aureus (S. aureus) while the bioinert glass nanofibers show a bacteriostatic effect also dose-dependent. The antibacterial activity has been related to the release of alkaline ions, the increase of pH of the medium and also the formation of needle-like aggregates of calcium phosphate at the surface of the bioactive glass nanofibers which act as a physical mechanism against bacteria. The antibacterial properties give an additional value to the laser-spinning glass nanofibers for different biomedical applications, such as treating or preventing surgery-associated infections. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Transitividade dos verbos alternantes: uma proposta semântica

    Directory of Open Access Journals (Sweden)

    Larissa CIRÍACO

    2009-12-01

    Full Text Available Este artigo traz uma proposta semântica para se classificar os verbos alternantes quanto a sua transitividade. Parte-se de uma análise das propriedades semântico-lexicais acarretadas pelos verbos causativos do Português Brasileiro, assumindo-se ser a transitivi­dade um fenômeno de interface entre a sintaxe e a semântica lexical. A proposta mostra não só a propriedade semântica relevante para a transitividade, mas também os processos gerais responsáveis pelas alternâncias verbais.

  18. 3D reconstruction of SEM images by use of optical photogrammetry software.

    Science.gov (United States)

    Eulitz, Mona; Reiss, Gebhard

    2015-08-01

    Reconstruction of the three-dimensional (3D) surface of an object to be examined is widely used for structure analysis in science and many biological questions require information about their true 3D structure. For Scanning Electron Microscopy (SEM) there has been no efficient non-destructive solution for reconstruction of the surface morphology to date. The well-known method of recording stereo pair images generates a 3D stereoscope reconstruction of a section, but not of the complete sample surface. We present a simple and non-destructive method of 3D surface reconstruction from SEM samples based on the principles of optical close range photogrammetry. In optical close range photogrammetry a series of overlapping photos is used to generate a 3D model of the surface of an object. We adapted this method to the special SEM requirements. Instead of moving a detector around the object, the object itself was rotated. A series of overlapping photos was stitched and converted into a 3D model using the software commonly used for optical photogrammetry. A rabbit kidney glomerulus was used to demonstrate the workflow of this adaption. The reconstruction produced a realistic and high-resolution 3D mesh model of the glomerular surface. The study showed that SEM micrographs are suitable for 3D reconstruction by optical photogrammetry. This new approach is a simple and useful method of 3D surface reconstruction and suitable for various applications in research and teaching.

  19. Human cardiac telocytes: 3D imaging by FIB-SEM tomography.

    Science.gov (United States)

    Cretoiu, D; Hummel, E; Zimmermann, H; Gherghiceanu, M; Popescu, L M

    2014-11-01

    Telocyte (TC) is a newly identified type of cell in the cardiac interstitium (www.telocytes.com). TCs are described by classical transmission electron microscopy as cells with very thin and long telopodes (Tps; cellular prolongations) having podoms (dilations) and podomers (very thin segments). TCs' three-dimensional (3D) morphology is still unknown. Cardiac TCs seem to be particularly involved in long and short distance intercellular signalling and, therefore, their 3D architecture is important for understanding their spatial connections. Using focused ion beam scanning electron microscopy (FIB-SEM) we show, for the first time, the whole ultrastructural anatomy of cardiac TCs. 3D reconstruction of cardiac TCs by FIB-SEM tomography confirms that they have long, narrow but flattened (ribbon-like) telopodes, with humps generated by the podoms. FIB-SEM tomography also confirms the network made by TCs in the cardiac interstitium through adherens junctions. This study provides the first FIB-SEM tomography of a human cell type.

  20. Effects of erbium-and chromium-doped yttrium scandium gallium garnet and diode lasers on the surfaces of restorative dental materials: a scanning electron microscope study.

    Science.gov (United States)

    Hatipoglu, M; Barutcigil, C

    2015-01-01

    The aim of this study is to evaluate the potential effects of laser irradiation, which is commonly performed in periodontal surgery, on the surfaces of restorative materials. Five different restorative dental materials were used in this study, as follows: (1) Resin composite, (2) poly acid-modified resin composite (compomer), (3) conventional glass ionomer cement (GIC), (4) resin-modified glass ionomer cement (RMGIC), and (5) amalgam. Four cylindrical samples (8 mm diameter, 2 mm height) were prepared for each restorative material. In addition, four freshly extracted, sound human incisors teeth were selected. Two different laser systems commonly used in periodontal surgery were examined in this study: A 810 nm diode laser at a setting of 1 W with continuous-phase laser irradiation for 10 s, and an erbium-and chromium-doped yttrium scandium gallium garnet (Er, Cr: YSGG) laser at settings of 2.5 W, 3.25 W, and 4 W with 25 Hz laser irradiation for 10 s. Scanning electron microscopy (SEM) analysis was performed to evaluate the morphology and surface deformation of the restorative materials and tooth surfaces. According to the SEM images, the Er, Cr: YSGG laser causes irradiation markings that appear as demineralized surfaces on tooth samples. The Er, Cr: YSGG laser also caused deep defects on composite, compomer, and RMGIC surfaces because of its high power, and the ablation was deeper for these samples. High-magnification SEM images of GIC samples showed the melting and combustion effects of the Er, Cr: YSGG laser, which increased as the laser power was increased. In amalgam samples, neither laser left significant harmful effects at the lowest power setting. The diode laser did cause irradiation markings, but they were insignificant compared with those left by the Er, Cr: YSGG laser on the surfaces of the different materials and teeth. Within the limitations of this study, it can be concluded that Er, Cr: YSGG laser irradiation could cause distortions of the surfaces

  1. Ge nanocrystals with highly uniform size distribution deposited on alumina at room temperature by pulsed laser deposition: structural, morphological, and charge trapping properties

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Sanchez, J., E-mail: javier.martin.nano@gmail.com; Marques, L.; Vieira, E. M. F. [University of Minho, Department of Physics and Centre of Physics (Portugal); Doan, Q. T.; Marchand, A.; El Hdiy, A. [LMEN, Universite de Reims Champagne-Ardenne (France); Rolo, A. G.; Pinto, S. R. C.; Ramos, M. M. D.; Chahboun, A.; Gomes, M. J. M. [University of Minho, Department of Physics and Centre of Physics (Portugal)

    2012-05-15

    In this work, we report on the synthesis of Ge nanocrystals (NCs) by pulsed laser deposition (PLD) at room temperature (RT) in an argon atmosphere without any further annealing process. Our results show that functional thin films of crystalline Ge nanoparticles with spherical shapes can be obtained by PLD directly on alumina layers deposited on n-doped Si (100) substrates. In addition, we also demonstrate that a uniform size distribution of NCs with an average diameter of about 3 nm and a density of 2.3 Multiplication-Sign 10{sup 11} cm{sup -2} can be obtained by optimizing a shadow mask set-up, where a solid disk is introduced between the target and the substrate. Charge/discharge effects in Ge NCs deposited on a high-k amorphous alumina layer are also evidenced by conductive atomic force microscopy, which makes them suitable for memory applications.

  2. Residual Stress, Defects and Grain Morphology of Ti-6Al-4V Alloy Produced by Ultrasonic Impact Treatment Assisted Selective Laser Melting

    Directory of Open Access Journals (Sweden)

    Meixia Zhang

    2016-10-01

    Full Text Available For large-scale selective laser melting (SLM additive manufacturing technology, three main problems severely restrict its development and application, namely the residual stress, defects, and columnar grains with anisotropy. To overcome these problems, a new method is proposed by combining SLM with ultrasonic impact treatment (UIT technique. This study explores the feasibility of UIT assisted SLM, as well as the effect of UIT on the residual stress, defects and β grains of Ti-6Al-4V alloy sample. The results indicate that after the application of UIT during SLM, residual stress can be largely reduced and defects can be hammered flat and even eliminated. Meanwhile, the epitaxial growth of columnar grains is prevented, and fine equiaxed grains are formed due to plastic deformation and recrystallization.

  3. Permeability of Dental Adhesives - A SEM Assessment.

    Science.gov (United States)

    Malacarne-Zanon, Juliana; de Andrade E Silva, Safira M; Wang, Linda; de Goes, Mario F; Martins, Adriano Luis; Narvaes-Romani, Eliene O; Anido-Anido, Andrea; Carrilho, Marcela R O

    2010-10-01

    To morphologically evaluate the permeability of different commercial dental adhesives using scanning electron microscopy. SEVEN ADHESIVE SYSTEMS WERE EVALUATED: one three-step system (Scotchbond Multi-Purpose - MP); one two-step self-etching primer system (Clearfil SE Bond - SE); three two-step etch-and-rinse systems (Single Bond 2 - SB; Excite - EX; One-Step - OS); and two single-step self-etching adhesives (Adper Prompt - AP; One-Up Bond F - OU). The mixture of primer and bond agents of the Clearfil SE Bond system (SE-PB) was also tested. The adhesives were poured into a brass mold (5.8 mm x 0.8 mm) and light-cured for 80 s at 650 mW/cm2. After a 24 h desiccation process, the specimens were immersed in a 50% ammoniac silver nitrate solution for tracer permeation. Afterwards, they were sectioned in ultra-fine slices, carbon-coated, and analyzed under backscattered electrons in a scanning electron microscopy. MP and SE showed slight and superficial tracer permeation. In EX, SB, and OS, permeation extended beyond the inner superficies of the specimens. SE-PB did not mix well, and most of the tracer was precipitated into the primer agent. In AP and OU, "water-trees" were observed all over the specimens. Different materials showed distinct permeability in aqueous solution. The extent of tracer permeation varied according to the composition of each material and it was more evident in the more hydrophilic and solvated ones.

  4. Microstructure and corrosion behavior of austenitic stainless steel treated with laser

    Science.gov (United States)

    Khalfallah, I. Y.; Rahoma, M. N.; Abboud, J. H.; Benyounis, K. Y.

    2011-06-01

    Surface modification of AISI316 stainless steel by laser melting was investigated experimentally using 2 and 4 kW laser power emitted from a continuous wave CO 2 laser at different specimen scanning speeds ranged from 300 to 1500 mm/min. Also, an investigation is reported of the introduction of carbon into the same material by means of laser surface alloying, which involves pre-coating the specimen surfaces with graphite powder followed by laser melting. The aim of these treatments is to enhance corrosion resistance by the rapid solidification associated with laser melting and also to increase surface hardness without affecting the bulk properties by increasing the carbon concentration near the surface. Different metallurgical techniques such as optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to characterize the microstructure of the treated zone. The microstructures of the laser melted zones exhibited a dendritic morphology with a very fine scale with a slight increase in hardness from 200 to 230 Hv. However, the laser alloyed samples with carbon showed microstructure consisting of γ dendrite surrounded by a network of eutectic structures (γ+carbide). A significant increase in hardness from 200 to 500 Hv is obtained. Corrosion resistance was improved after laser melting, especially in the samples processed at high laser power (4 kW). There was shift in Icorr and Ecorr toward more noble values and a lower passive current density than that of the untreated materials. These improvements in corrosion resistance were attributed to the fine and homogeneous dendritic structure, which was found throughout the melted zones. The corrosion resistance of the carburized sample was lower than the laser melted sample.

  5. Morphological Analysis (SEM) of the Surface of a Non-Noble Dental Alloy Subjected to Electrocorrosion

    Science.gov (United States)

    Baciu, E. R.; Grădinaru, I.; Baciu, M.; Vasluianu, R. I.; Cimpoesu, R.; Baciu, C.; Bejinariu, C.

    2017-06-01

    Corrosion consists in the degradation of a material under the chemical or electrochemical action of the environment where it is placed. The investigations carried out aimed to show the structural modifications produced in Co-Cr-Mo alloy, Robur 400 (Eisenbacher Dental - Waren ED GmbH, Germany) subjected to electrocorrosion in Fusayama-Mayer artificial saliva. The specimens prepared by mechanical polishing were analysed structurally by using a scanning electron microscope. During the tests run we could notice a general corrosion of the surfaces of the specimens made from Robur alloy. Through 2D and 3D microscopy and qualitative determinations of the luminous variation we could notice the effects of electrocorrosion tests on the surface of the metal material.

  6. Mapping the Complex Morphology of Cell Interactions with Nanowire Substrates Using FIB-SEM

    DEFF Research Database (Denmark)

    Wierzbicki, Rafal; Købler, Carsten; Jensen, Mikkel Ravn Boye;

    2013-01-01

    a wide phenotypic variability. Depending on the substrate and cell, we observe that cells could for instance: break the nanowires and engulf them, flatten the nanowires or simply reside on top of them. Given the complexity of interactions, we have categorised our observations and created an overview map...

  7. SEM morphological studies of carbonates and the search for ancient life on Mars

    Science.gov (United States)

    D'Elia, M.; Blanco, A.; Galiano, A.; Orofino, V.; Fonti, S.; Mancarella, F.; Guido, A.; Russo, F.; Mastandrea, A.

    2017-04-01

    Next space missions will investigate the possibility of extinct or extant life on Mars. Studying the infrared spectral modifications, induced by thermal processing on different carbonate samples (recent shells and fossils of different ages), we developed a method able to discriminate biogenic carbonates from their abiogenic counterparts. The method has been successfully applied to microbialites, i.e. bio-induced carbonates deposits, and particularly to stromatolites, the laminated fabric of microbialites, some of which can be ascribed to among the oldest traces of biological activity known on Earth. These results are of valuable importance since such carbonates are linked to primitive living organisms that can be considered as good analogues for putative Martian life forms. Considering that the microstructures of biogenic carbonate are different from those of abiogenic origin, we investigated the micromorphology of shells, skeletal grains and microbialites at different scale with a scanning electron microscope. The results show that this line of research may provide an alternative and complementary approach to other techniques developed in the past by our group to distinguish biotic from abiotic carbonates. In this paper, we present some results that can be of valuable interest since they demonstrate the utility for a database of images concerning the structures and textures of relevant carbonate minerals. Such data may be useful for the analysis of Martian samples, coming from sample return missions or investigated by future in situ explorations, aimed to characterize the near-subsurface of Mars in search for past or present life.

  8. Morphology and mechanisms of picosecond ablation of metal films on fused silica substrates

    Science.gov (United States)

    Bass, Isaac L.; Negres, Raluca A.; Stanion, Ken; Guss, Gabe; Keller, Wesley J.; Matthews, Manyalibo J.; Rubenchik, Alexander M.; Yoo, Jae Hyuck; Bude, Jeffrey D.

    2016-12-01

    The ablation of magnetron sputtered metal films on fused silica substrates by a 1053 nm, picosecond class laser was studied as part of a demonstration of its use for in-situ characterization of the laser spot under conditions commonly used at the sample plane for laser machining and damage studies. Film thicknesses were 60 and 120 nm. Depth profiles and SEM images of the ablation sites revealed several striking and unexpected features distinct from those typically observed for ablation of bulk metals. Very sharp thresholds were observed for both partial and complete ablation of the films. Partial film ablation was largely independent of laser fluence with a surface smoothness comparable to that of the unablated surface. Clear evidence of material displacement was seen at the boundary for complete film ablation. These features were common to a number of different metal films including Inconel on commercial neutral density filters, stainless steel, and aluminum. We will present data showing the morphology of the ablation sites on these films as well as a model of the possible physical mechanisms producing the unique features observed.

  9. SEM Analysis of Residual Dentin Surface in Primary Teeth Using Different Chemomechanical Caries Removal Agents.

    Science.gov (United States)

    Thakur, Rachna; Patil, Sandya Devi S; Kush, Anil; Madhu, K

    The purpose of this in vitro study was to analyze the residual dentinal surfaces following caries removal using two chemomechanical methods (Papacarie Duo and Carie Care), by scanning electron microscopy (SEM). Twenty extracted primary molars with active occlusal carious lesions were randomly assigned two groups depending on the CMCR agent used for the caries excavation - Group 1 - with Papacarie Duo and Group - 2 with Carie Care. After the caries excavation, the specimens were subjected to SEM analysis. Though both the agents showed the minimal smear layer with the patent dentinal tubules, Carie care showed patent dentinal tubules with a clearly exposed peritubular and intertubular collagen network. Carie Care treated surface exhibited better surface morphology of residual dentin.

  10. Improving adhesion of copper/epoxy joints by pulsed laser ablation

    KAUST Repository

    Hernandez, Edwin

    2015-10-19

    The purpose of the present work is to analyze the effect of pulsed laser ablation on copper substrates (CuZn40) deployed for adhesive bonding. Surface pre-treatment was carried using an Yb-fiber laser beam. Treated surfaces were probed using Scanning Electron Microscopy (SEM) and X-Ray Photoelectron Spectroscopy (XPS). The mechanical performance of CuZn40/epoxy bonded joints was assessed using the T-peel test coupon. In order to resolve the mechanisms of failure and adhesive penetration within surface asperities induced by the laser treatment, fracture surfaces were surveyed using SEM. Finite element simulations, based on the use of the cohesive zone model of fracture, were carried out to evaluate the variation of bond toughness. Results indicated that the laser ablation process effectively modifies surface morphology and chemistry and enables enhanced mechanical interlocking and cohesive failure within the adhesive layer. Remarkable improvements of apparent peel energy and bond toughness were observed with respect to control samples with sanded substrates.

  11. Effects of Er:YAG laser on mineral content of sound dentin in primary teeth.

    Science.gov (United States)

    Guler, Cigdem; Malkoc, Meral Arslan; Gorgen, Veli Alper; Dilber, Erhan; Bulbul, Mehmet

    2014-01-01

    The aim of the present study was to evaluate the mineral content of sound dentin in primary teeth prepared using an Er:YAG laser at two different power settings. Thirty-six primary second molars were used in this study. Three dentin slabs were obtained from each tooth, and the slabs were randomly divided into three groups: Group A, control; Group B, Er:YAG laser at 3.5 W, 175 mJ, and 20 Hz, short pulse mode; and Group C, Er:YAG laser at 4 W, 200 mJ, and 20 Hz, medium-short pulse mode. One dentin slab per group was used to evaluate the dentinal morphology and surface roughness values using SEM and profilometer, respectively. Mineral content in the dentin slabs were calculated by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The data were analyzed by one-way analysis of variance and Tukey's HSD tests. No significant differences in Ca, K, Mg, Na, and P levels or Ca/P ratio were found among the groups (P > 0.05). SEM micrographs showed that surface irregularities increased with a higher power setting. The surface roughness after laser treatment in Group B and Group C was found to be similar, unlike Group A.

  12. Metal ion release from silver soldering and laser welding caused by different types of mouthwash.

    Science.gov (United States)

    Erdogan, Ayse Tuygun; Nalbantgil, Didem; Ulkur, Feyza; Sahin, Fikrettin

    2015-07-01

    To compare metal ion release from samples welded with silver soldering and laser welding when immersed into mouthwashes with different ingredients. A total of 72 samples were prepared: 36 laser welded and 36 silver soldered. Four samples were chosen from each subgroup to study the morphologic changes on their surfaces via scanning electron microscopy (SEM). Each group was further divided into four groups where the samples were submerged into mouthwash containing sodium fluoride (NaF), mouthwash containing sodium fluoride + alcohol (NaF + alcohol), mouthwash containing chlorhexidine (CHX), or artificial saliva (AS) for 24 hours and removed thereafter. Subsequently, the metal ion release from the samples was measured with inductively coupled plasma mass spectrometry (ICP-MS). The metal ion release among the solutions and the welding methods were compared. The Kruskal-Wallis and analysis of variance (ANOVA) tests were used for the group comparisons, and post hoc Dunn multiple comparison test was utilized for the two group comparisons. The level of metal ion release from samples of silver soldering was higher than from samples of laser welding. Furthermore, greater amounts of nickel, chrome, and iron were released from silver soldering. With regard to the mouthwash solutions, the lowest amounts of metal ions were released in CHX, and the highest amounts of metal ions were released in NaF + alcohol. SEM images were in accord with these findings. The laser welding should be preferred over silver soldering. CHX can be recommended for patients who have welded appliances for orthodontic reasons.

  13. Connecting SEM Analysis and Profile Analysis via MDS.

    Science.gov (United States)

    Kim, Se-Kang; Davison, Mark L.

    This study was designed to explain how Profile Analysis via Multidimensional Scaling (PAMS) could be viewed as a structural equations model (SEM). The study replicated the major profiles extracted from PAMS in the context of the latent variables in SEM. Data involved the Basic Theme Scales of the Strong Campbell Interest Inventory (Campbell and…

  14. Structural Equations and Causal Explanations: Some Challenges for Causal SEM

    Science.gov (United States)

    Markus, Keith A.

    2010-01-01

    One common application of structural equation modeling (SEM) involves expressing and empirically investigating causal explanations. Nonetheless, several aspects of causal explanation that have an impact on behavioral science methodology remain poorly understood. It remains unclear whether applications of SEM should attempt to provide complete…

  15. Web semántica y servicios web semanticos

    OpenAIRE

    Marquez Solis, Santiago

    2007-01-01

    Des d'aquest TFC volem estudiar l'evolució de la Web actual cap a la Web Semàntica. Desde este TFC queremos estudiar la evolución de la Web actual hacia la Web Semántica. From this Final Degree Project we want to study the evolution of the current Web to the Semantic Web.

  16. On the Nature of SEM Estimates of ARMA Parameters.

    Science.gov (United States)

    Hamaker, Ellen L.; Dolan, Conor V.; Molenaar, Peter C. M.

    2002-01-01

    Reexamined the nature of structural equation modeling (SEM) estimates of autoregressive moving average (ARMA) models, replicated the simulation experiments of P. Molenaar, and examined the behavior of the log-likelihood ratio test. Simulation studies indicate that estimates of ARMA parameters observed with SEM software are identical to those…

  17. Quantitative Analysis of Micro-porosity of Eco-material by Using SEM Technique

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ji-ru; LIU Yuan-zhi; LIU Zu-de

    2004-01-01

    Microstructure of the eco-material combining vegetation recovery with slope protection is important for determining plant-growing properties.Several techniques for analyzing the eco-material microstructure are presented,including the freeze-cut-drying method of preparing samples for scanning electronic microscopy (SEM),the SEM image processing technique and quantifying analysis method of the SEM images,and etc.The aggregates and pores in SEM images are identified using the different mathematics operators,and their effects are compared.The areas of aggregates and pores are obtained using the operator of morphology,and the influences of different thresholds in image segmentation are also discussed.The results show that the method,in which the variation of non-maximum grey-level gradient is limited,improves the effect of edge detections due to a weak distinction existing at the edge between the aggregates and pores in image.The determination of the threshold should combine the image characteristic with filling operation,so as to assure the precision of the image analysis,in which the contact-segmentation is the simplest and most effective method.The results also show that the pore areas in eco-materials are generally larger than those in the correlative soils,and their increment is large as soil fabric being fine.These differences are related to admixture of expansive perliticThe operator of morphology provides a new method for the image analysis of other porous material microstructure such as soils and concretes.

  18. Morphological aspects of Schistosoma mansoni adult worms isolated from nourished and undernourished mice: a comparative analysis by confocal laser scanning microscopy

    Directory of Open Access Journals (Sweden)

    Neves Renata Heisler

    2001-01-01

    Full Text Available Malnutrition hampers the course of schistosomiasis mansoni infection just as normal growth of adult worms. A comparative morphometric study on adult specimens (male and female recovered from undernourished (fed with a low protein diet - regional basic diet and nourished (rodent commercial laboratory food, NUVILAB white mice was performed. Tomographic images and morphometric analysis of the oral and ventral suckers, reproductive system and tegument were obtained by means of confocal laser scanning microscopy. Undernourished male specimens presented smaller morphometric values (length and width of the reproductive system (first, third and last testicular lobes and thickness of the tegument than controls. Besides that, it was demonstrated that the dorsal surface of the male worms bears large tubercles unevenly distributed, but kept grouped and flat. At the subtegumental region, vacuolated areas were detected. It was concluded that the inadequate nutritional status of the vertebrate host has a negative influence mainly in the reproductive system and topographical somatic development of male adult Schistosoma mansoni, inducing some alterations on the structure of the parasite.

  19. Effects of Nd:YAG laser irradiation on structural, morphological, cation distribution and magnetic properties of nanocrystalline CoFe{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Mane, Maheshkumar L., E-mail: mane.maheshkumar@hotmail.com [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India); Dhage, Vinod N. [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India); Sundar, R.; Ranganathan, K.; Oak, S.M. [Solid State Laser Division, Raja Ramanna Center for Advanced Technology, Indore (M.P.) (India); Shengule, D.R.; Jadhav, K.M. [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S.) 431004 (India)

    2011-08-01

    The cobalt ferrite nanoparticles of 20 nm size were synthesized by sol-gel auto-combustion technique. The samples were irradiated with Nd:YAG laser to understand the effects of irradiation on structural, cation distribution and magnetic properties. The virgin and irradiated samples were characterized by X-ray diffraction technique. The X-ray diffraction studies at room temperature shows that defects were created in the lattice after irradiation which causes effects on structural, cation distribution and magnetic properties. The energy dispersive analysis of X-rays (EDAX) showed the chemical composition is as per the expected stichiometry. The lattice constant observed from XRD data for virgin and irradiated samples shows increasing trend after irradiation. Cation distribution was investigated by using X-ray diffraction method. We observe decrease in magnetization of the samples after irradiation. The observed reduction in the saturation magnetization after irradiation can be understood on the basis of the partial formation of paramagnetic centers and rearrangement of cations in the lattice.

  20. Influence of reactive oxygen ambience on the structural, morphological and optical properties of pulsed laser ablated potassium lithium niobate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jayasree, V. [Department of Optoelectronics, University of Kerala, Kariavattom, Thiruvananthapuram 695 581, Kerala (India); Ratheesh, R. [Centre for Materials for Electronics Technology, Athani P. O, Thrissur, Kerala (India); Ganesan, V.; Reddy, V.R. [UGC-DAE Consortium for Scientific Research, Indore Centre, Madhya Pradesh (India); Sudarsanakumar, C. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala (India); Pillai, V.P. Mahadevan [Department of Optoelectronics, University of Kerala, Kariavattom, Thiruvananthapuram 695 581, Kerala (India)], E-mail: vpmpillai9@rediffmail.com; Nayar, V.U. [Department of Optoelectronics, University of Kerala, Kariavattom, Thiruvananthapuram 695 581, Kerala (India)

    2008-11-28

    The effect of oxygen ambience on the structure and properties of potassium lithium niobate (K{sub 3}Li{sub 2}Nb{sub 5}O{sub 15}: KLN) films prepared on glass substrates by pulsed laser ablation technique (PLD) are studied. The influence of annealing on the properties of vacuum deposited films is also investigated. The Gracing Incidence X-ray Diffraction (GIXRD) data suggests the tetragonal structure for the KLN film whose grain sizes increase on thermal annealing. The Atomic Force Microscopic (AFM) analysis reveals the four-fold symmetric nature of the grains in the films. Self assembly of grains in the form of rings and rods are observed in AFM images of the films deposited in an oxygen ambience of 2 Pa. The films deposited at higher oxygen ambience show a blue shift in optical band gap. The direct current (DC) resistance measurement on the films deposited at non-reactive ambience reveals resistivity in the range of k{omega} m.

  1. Scanning electron microscopy: preparation and imaging for SEM.

    Science.gov (United States)

    Jones, Chris G

    2012-01-01

    Scanning electron microscopy (SEM) has been almost universally applied for the surface examination and characterization of both natural and man-made objects. Although an invasive technique, developments in electron microscopy over the years has given the microscopist a much clearer choice in how invasive the technique will be. With the advent of low vacuum SEM in the 1970s (The environmental cold stage, 1970) and environmental SEM in the late 1980s (J Microsc 160(pt. 1):9-19, 1989), it is now possible in some circumstances to examine samples without preparation. However, for the examination of biological tissue and cells it is still advisable to chemically fix, dehydrate, and coat samples for SEM imaging and analysis. This chapter aims to provide an overview of SEM as an imaging tool, and a general introduction to some of the methods applied for the preparation of samples.

  2. Histological observation on dental hard tissue irradiated by ultrashort-pulsed laser

    Science.gov (United States)

    Uchizono, Takeyuki; Awazu, Kunio; Igarashi, Akihiro; Kato, Junji; Hirai, Yoshito

    2006-04-01

    In the field of dentistry, effectiveness of USPL irradiation is researched because USPL has less thermal side effect to dental hard tissue. In this paper, we observed morphological change and optical change of dental hard tissue irradiated by USPL for discussing the safety and effectiveness of USPL irradiation to dental hard tissues. Irradiated samples were crown enamel and root dentin of bovine teeth. Lasers were Ti:sapphire laser, which had pulse duration (P d)of 130 fsec and pulse repetition rate (f) of 1kHz and wavelength (l) of 800nm, free electron laser (FEL), which had P d of 15 μsec and f of 10Hz and wavelength of 9.6μm, and Er:YAG laser, which had P d of 250 μsec and f of 10Hz and wavelength of 2.94μm. After laser irradiation, the sample surfaces and cross sections were examined with SEM and EDX. The optical change of samples was observed using FTIR. In SEM, the samples irradiated by USPL had sharp and accurate ablation with no crack and no carbonization. But, in FEL and Er:YAG laser, the samples has rough ablation with crack and carbonization. It was cleared that the P/Ca ratio of samples irradiated by USPL had same value as non-irradiated samples. There was no change in the IR absorption spectrum between samples irradiated by USPL and non-irradiated sample. But, they of samples irradiated by FEL and Er:YAG laser, however, had difference value as non-irradiated samples. These results showed that USPL might be effective to ablate dental hard tissue without thermal damage.

  3. Dynamics of Gradient Bioceramic Composite Coating on Surface of Titanium Alloy by Wide-Band Laser Cladding

    Institute of Scientific and Technical Information of China (English)

    LIU Qi-bin; ZOU Long-jiang; ZHU Wei-dong; LI Hai-tao; DONG Chuang

    2004-01-01

    The gradient bioceramic coating was prepared on the surface of titanium alloy using wide-band laser cladding. The dynamics of gradient bioceramic composite coating containing hydroxyapatite (HA) prepared with mixture of CaHPO4*2H2O and CaCO3 under the condition of wide-band laser was studied theoretically. The corresponding mathematical model and its numerical solution were presented. The examination experiment showed that HA bioceramic composite coatings can be obtained by appropriately choosing wide-band laser cladding parameters. The microstructure and surface morphology of HA bioceramic coating were observed by SEM and X-ray diffraction. The experimental results showed that the bioceramic coating is composed of HA, β-TCP, CaO, CaTiO3 and TiO2. The surface of bioceramic coating takes coral-shaped structure or short-rod piled structure, which helps osteoblast grow into bioceramic and improves the biocompatibility.

  4. Fabrication of hydrophobic structures on coronary stent surface based on direct three-beam laser interference lithography

    Science.gov (United States)

    Gao, Long-yue; Zhou, Wei-qi; Wang, Yuan-bo; Wang, Si-qi; Bai, Chong; Li, Shi-ming; Liu, Bin; Wang, Jun-nan; Cui, Cheng-kun; Li, Yong-liang

    2016-05-01

    To solve the problems with coronary stent implantation, coronary artery stent surface was directly modified by three-beam laser interference lithography through imitating the water-repellent surface of lotus leaf, and uniform micro-nano structures with the controllable period were fabricated. The morphological properties and contact angle (CA) of the microstructure were measured by scanning electron microscope (SEM) and CA system. The water repellency of stent was also evaluated by the contact and then separation between the water drop and the stent. The results show that the close-packed concave structure with the period of about 12 μm can be fabricated on the stent surface with special parameters (incident angle of 3°, laser energy density of 2.2 J·cm-2 and exposure time of 80 s) by using the three-beam laser at 1 064 nm, and the structure has good water repellency with CA of 120°.

  5. Surface nano-texturing of silicon by picosecond laser irradiation through TiO2 nanotube arrays

    Science.gov (United States)

    Babu, K. E. Sarath Raghavendra; Duraiselvam, Muthukannan

    2015-10-01

    This article presents, nano-texturing of crystalline silicon by irradiating picosecond laser with variable spatial intensity, caused by optically non-linear TiO2 nanotube arrays (TNTA). Along with micro-scale surface structure, highly ordered laser-induced periodic surface structures (LIPSS) was observed at nano-scale. The periodicity (Λ) of the LIPSS generated was near to the laser wavelength (532 nm). Surface morphology at micro-level was characterized by optical microscopy (OM) and white light interferometer (WLI) and at the nano-scale by scanning electron microscope (SEM) and atomic force microscope (AFM). The results highlight the potential use of TNTA as a single step process to produce micro/nanostructures without any gas/liquid medium under ambient condition.

  6. The use of gamma irradiation in preparation of polybutadiene rubber nanopowder; Its effect on particle size, morphology and crosslink structure of the powder

    Science.gov (United States)

    Rezaei Abadchi, Majid; Jalali-Arani, Azam

    2014-02-01

    The aim of this work was the preparation and characterization of polybutadiene rubber (BR) powder by irradiating of rubber lattices using 60Co radiation and spray-drying of them at the appropriate condition. The influences of absorbed dose on the volume swelling ratio, molecular weight between crosslinks, gel fraction, and glass transition temperature of obtained powder were studied. Morphology, size and size distribution of rubber particles were examined by using scanning electron microscopy (SEM) and laser particle size analyzer (LPSA) technique, respectively. Results obtained by LPSA revealed that radiation has no effect on particle size of rubber latex but after drying, adherence properties of rubber particle causes increase in particle size of rubber powder, as shown in SEM photograph. Fourier transform infrared spectroscopy of rubber powders confirmed that with increasing the irradiation dose, characteristic peak corresponds to the >Cdbnd Cradiation yield.

  7. In vitro study of 960 nm high power diode laser applications in dental enamel, aided by the presence of a photoinitiator dye: scanning electron microscopy analysis; Estudo in vitro das aplicacoes do laser de diodo de alta potencia 960 nm em esmalte dentario, assistido por um fotoiniciador: analise de microscopia eletronica de varredura

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Marcelo Vinicius de

    2002-06-15

    The objective of this study is to verify if a high power diode laser can effectively modify the morphology of an enamel surface, and if this can be done in a controlled fashion by changing the lasers parameters. Previous studies using SEM demonstrated that through irradiation with Nd:YAG laser (1064 nm) it is possible to modify the morphology of the dental surface in such way as to increase its resistance against caries decays. The desired procedures that should achieve a decrease of the index of caries decays and of its sequels are on a primary level, which means that action is necessary before the disease installs itself. In this study it was used for the first time a prototype of a high power diode laser operating at 960 nm, produced by the Laboratory of Development of Lasers of the Center for Lasers and Applications of the IPEN. This equipment can present several advantages as reliability, reduced size and low cost. The aim was establish parameters of laser irradiation that produce the desired effects wanted in the enamel and protocols that guarantee its safety during application in dental hard tissues, protecting it of heating effects such as fissures and carbonization. (author)

  8. Effect of fluence and ambient environment on the surface and structural modification of femtosecond laser irradiated Ti

    Science.gov (United States)

    Umm-i-Kalsoom; Shazia, Bashir; Nisar, Ali; M Shahid, Rafique; Wolfgang, Husinsky; Chandra, S. R. Nathala; Sergey, V. Makarov; Narjis, Begum

    2016-01-01

    Under certain conditions, ultrafast pulsed laser interaction with matter leads to the formation of self-organized conical as well as periodic surface structures (commonly reffered to as, laser induced periodic surface structures, LIPSS). The purpose of the present investigations is to explore the effect of fsec laser fluence and ambient environments (Vacuum & O2) on the formation of LIPSS and conical structures on the Ti surface. The surface morphology was investigated by scanning electron microscope (SEM). The ablation threshold with single and multiple (N = 100) shots and the existence of an incubation effect was demonstrated by SEM investigations for both the vacuum and the O2 environment. The phase analysis and chemical composition of the exposed targets were performed by x-ray diffraction (XRD) and energy dispersive x-ray spectroscopy (EDS), respectively. SEM investigations reveal the formation of LIPSS (nano & micro). FFT d-spacing calculations illustrate the dependence of periodicity on the fluence and ambient environment. The periodicity of nano-scale LIPSS is higher in the case of irradiation under vacuum conditions as compared to O2. Furthermore, the O2 environment reduces the ablation threshold. XRD data reveal that for the O2 environment, new phases (oxides of Ti) are formed. EDS analysis exhibits that after irradiation under vacuum conditions, the percentage of impurity element (Al) is reduced. The irradiation in the O2 environment results in 15% atomic diffusion of oxygen. Project supported by Österreichische Forschungsfödergesellschaft (FFG) (Grant No. 834325).

  9. SEM, EDS, PL and absorbance study of CdTe thin films grown by CSS method

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Torres, M.E.; Silva-Gonzalez, R.; Gracia-Jimenez, J.M. [Instituto de Fisica, BUAP, Apdo. Postal J-48, San Manuel, 72570 Puebla, Pue. (Mexico); Casarrubias-Segura, G. [CIE- UNAM, 62580 Temixco, Morelos (Mexico)

    2006-09-22

    Oxygen-doped CdTe films were grown on conducting glass substrates by the close spaced sublimation (CSS) method and characterized using SEM, EDS, photoluminescence (PL) and absorbance. A significant change in the polycrystalline morphology is observed when the oxygen proportion is increased in the deposition atmosphere. The EDS analysis showed that all samples are nonstoichiometric with excess Te. The PL spectra show emission bands associated with Te vacancies (V{sub Te}), whose intensities decrease as the oxygen proportion in the CSS chamber is increased. The oxygen impurities occupy Te vacancies and modify the surfaces states, improving the nonradiative process. (author)

  10. Bond strengths of all-ceramics: acid vs laser etching.

    Science.gov (United States)

    Gökçe, B; Ozpinar, B; Dündar, M; Cömlekoglu, E; Sen, B H; Güngör, M A

    2007-01-01

    Various applications of dental lasers on dental materials have been proposed for surface modifications. This study evaluated whether laser etching could be an alternative to hydrofluoric acid (HF) etching. One hundred and ten lithia-based all-ceramic specimens (Empress 2) (R: 4 mm, h: 4 mm) were prepared and divided into five groups (n = 22/group). The untreated specimens served as the control, while one of the experimental groups was treated with 9.5% HF for 30 seconds. Three remaining test groups were treated with different laser (Er:YAG laser wavelength:2940 nm, OpusDent) power settings: 300 mJ, 600 mJ and 900 mJ. Ten specimens in each group were luted to the other 10 specimens by a dual-curing cement (Variolink II), and shear-bond strength (SBS) tests were performed (Autograph, crosshead speed: 0.5 mm/minute). The results were statistically analyzed (Kruskal Wallis and Mann Whitney-U, alpha = .05). Mean SBS (MPa) were 31.9 +/- 4.0, 41.4 +/- 4.3, 42.8 +/- 6.2, 29.2 +/- 4.5 and 27.4 +/- 3.8 for the control and HF, 300, 600 and 900 mJ groups, respectively. SEM evaluations revealed different surface morphologies depending on the laser parameters. The differences between HF acid and 300 mJ, when compared with the control, 600 and 900 mJ groups, were significant (p < .05). The 300 mJ laser group exhibited the highest shear-bond strength values, indicating that laser etching could also be used for surface treatments.

  11. 3D imaging of cells and tissues by focused ion beam/scanning electron microscopy (FIB/SEM).

    Science.gov (United States)

    Drobne, Damjana

    2013-01-01

    Integration of a scanning electron microscope (SEM) and focused ion beam (FIB) technology into a single FIB/SEM system permits use of the FIB as a nano-scalpel to reveal site-specific subsurface microstructures which can be examined in great detail by SEM. The FIB/SEM technology is widely used in the semiconductor industry and material sciences, and recently its use in the life sciences has been initiated. Samples for FIB/SEM investigation can be either embedded in a plastic matrix, the traditional means of preparation of transmission electron microscopy (TEM) specimens, or simply dried as in samples prepared for SEM imaging. Currently, FIB/SEM is used in the life sciences for (a) preparation by the lift-out technique of lamella for TEM analysis, (b) tomography of samples embedded in a matrix, and (c) in situ site-specific FIB milling and SEM imaging using a wide range of magnifications. Site-specific milling and imaging has attracted wide interest as a technique in structural research of single eukaryotic and prokaryotic cells, small animals, and different animal tissue, but it still remains to be explored more thoroughly. In the past, preparation of samples for site-specific milling and imaging by FIB/SEM has typically adopted the embedding techniques used for TEM samples, and which have been very well described in the literature. Sample preparation protocols for the use of dried samples in FIB/SEM have been less well investigated. The aim of this chapter is to encourage application of FIB/SEM on dried biological samples. A detailed description of conventional dried sample preparation and FIB/SEM investigation of dried biological samples is presented. The important steps are described and illustrated, and direct comparison between embedded and dried samples of same tissues is provided. The ability to discover links between gross morphology of the tissue or organ, surface characteristics of any selected region, and intracellular structural details on the nanometer

  12. Smart flexible microrobots for scanning electron microscope (SEM) applications

    Science.gov (United States)

    Schmoeckel, Ferdinand; Fatikow, Sergej

    2000-06-01

    In the scanning electron microscope (SEM), specially designed microrobots can act as a flexible assembly facility for hybrid microsystems, as probing devices for in-situ tests on IC structures or just as a helpful teleoperated tool for the SEM operator when examining samples. Several flexible microrobots of this kind have been developed and tested. Driven by piezoactuators, these few cubic centimeters small mobile robots perform manipulations with a precision of up to 10 nm and transport the gripped objects at speeds of up to 3 cm/s. In accuracy, flexibility and price they are superior to conventional precision robots. A new SEM-suited microrobot prototype is described in this paper. The SEM's vacuum chamber has been equipped with various elements like flanges and CCD cameras to enable the robot to operate. In order to use the SEM image for the automatic real-time control of the robots, the SEM's electron beam is actively controlled by a PC. The latter submits the images to the robots' control computer system. For obtaining three-dimensional information in real time, especially for the closed-loop control of a robot endeffector, e.g. microgripper, a triangulation method with the luminescent spot of the SEM's electron beam is being investigated.

  13. Automated CD-SEM metrology for efficient TD and HVM

    Science.gov (United States)

    Starikov, Alexander; Mulapudi, Satya P.

    2008-03-01

    CD-SEM is the metrology tool of choice for patterning process development and production process control. We can make these applications more efficient by extracting more information from each CD-SEM image. This enables direct monitors of key process parameters, such as lithography dose and focus, or predicting the outcome of processing, such as etched dimensions or electrical parameters. Automating CD-SEM recipes at the early stages of process development can accelerate technology characterization, segmentation of variance and process improvements. This leverages the engineering effort, reduces development costs and helps to manage the risks inherent in new technology. Automating CD-SEM for manufacturing enables efficient operations. Novel SEM Alarm Time Indicator (SATI) makes this task manageable. SATI pulls together data mining, trend charting of the key recipe and Operations (OPS) indicators, Pareto of OPS losses and inputs for root cause analysis. This approach proved natural to our FAB personnel. After minimal initial training, we applied new methods in 65nm FLASH manufacture. This resulted in significant lasting improvements of CD-SEM recipe robustness, portability and automation, increased CD-SEM capacity and MT productivity.

  14. Infrared spectra, Raman laser, XRD, DSC/TGA and SEM investigations on the preparations of selenium metal, (Sb2O3, Ga2O3, SnO and HgO) oxides and lead carbonate with pure grade using acetamide precursors

    Indian Academy of Sciences (India)

    Moamen S Refat; Khaled M Elsabawy

    2011-07-01

    Ga2O3, Se metal, SnO, Sb2O3, HgO and PbCO3 are formed upon the reaction of acetamide aqueous solutions with Ga(NO3)3, SeO2, SnCl2, SbCl3, HgCl2 and Pb(NO3)2, respectively, at 90°C. Different amorphous or crystalline phases can be obtained depending upon the experimental conditions (molar ratios, metal salts and temperature). The chemical mechanisms for the formations of this metal, oxides or carbonate are discussed and the X-ray diffraction, scanning electron microscopy (SEM) and atomic force microscope (AFM) are described. The type of metal ions plays an important role in the decomposition of acetamide, leading to the formation of solid stable (metal, oxides or carbonate), soluble and gases species. These new precursors are more stable preventing the rapid precipitation of metal, oxides or carbonate. Furthermore, this route allows the formation of pure compounds in solutions.

  15. Morfologia externa do adulto de Hemiargus hanno (Stoll (Lepidoptera, Lycaenidae, Polyommatinae, Polyommatini: I. cabeça Adult exoskeletal morphology of Hemiargus hanno (Stoll (Lepidoptera, Lycaenidac, Polyommatinae, Polyommatini: I. head morphology

    Directory of Open Access Journals (Sweden)

    Marcelo Duarte

    2001-03-01

    Full Text Available This is the first of a series of contributions concerning exoskeletal morphology of neotropical lycaenid butterflies (blues and hairstreaks. The cephalic capsule morphology of Hemiargus hanno (Stoll, 1790 is herein presented with drawings and SEM photographs.

  16. Microstructure and Properties of Laser Additive Manufacturing TC Bearing

    Directory of Open Access Journals (Sweden)

    YANG Jiao-xi

    2016-07-01

    Full Text Available In order to solve the problem of uneven wear of TC bearing that conventional method brought and improve its service life,wear-resistant coating was fabricated on the surface of steel parts matrix with the method of laser additive manufacture. The Cr3C2/Fe based alloy was deposited by laser cladding technique on the inner-sleeve cylindrical and outer-sleeve bore of TC bearing with two different process parameters. The high-performance coating was obtained respectively, of cracks free,no pores and with good metallurgical quality. The morphology of the laser cladding coating was observed by scanning electronic microscope (SEM,the composition was analyzed by EDS,the phase transformation was characterized by XRD. The wear resistance,corrosion resistance and hardness of the laser cladding layer were tested by friction and wear tester,salt spray test chamber and digital micro-hardness tester respectively. The results show that the average micro-hardness of composite coating is HV700. The wear resistance of the composite coating is about 3 times as much as the Ni-based alloy. The corrosion resistance is close to 316L stainless steel.

  17. Improvement of geometrical measurements from 3D-SEM reconstructions

    DEFF Research Database (Denmark)

    Carli, Lorenzo; De Chiffre, Leonardo; Horsewell, Andy

    2009-01-01

    The quantification of 3D geometry at the nanometric scale is a major metrological challenge. In this work geometrical measurements on cylindrical items obtained with a 3D-SEM were investigated. Two items were measured: a wire gauge having a 0.25 mm nominal diameter and a hypodermic needle having...... that the diameter estimation performed using the 3D-SEM leads to an overestimation of approx. 7% compared to the reference values obtained using a 1-D length measuring machine. Standard deviation of SEM measurements performed on the wire gauge is approx. 1.5 times lower than the one performed on the hypodermic...

  18. SEM-EBSP能知道些什么

    Institute of Scientific and Technical Information of China (English)

    张唯敏

    2003-01-01

    @@ 1 SEM-EBSP是什么 所谓SEM-EBSP是指采用在扫描电子显微镜(SEM)镜体中的反射电子菊池线衍射的结晶方位分析.被称为菊池图形的衍射图形可因结晶的稍许倾斜而大大地改变其位置,因此,通过解析菊池图形就能正确地知道结晶方位.

  19. Improvement of CD-SEM mark position measurement accuracy

    Science.gov (United States)

    Kasa, Kentaro; Fukuhara, Kazuya

    2014-04-01

    CD-SEM is now attracting attention as a tool that can accurately measure positional error of device patterns. However, the measurement accuracy can get worse due to pattern asymmetry as in the case of image based overlay (IBO) and diffraction based overlay (DBO). For IBO and DBO, a way of correcting the inaccuracy arising from measurement patterns was suggested. For CD-SEM, although a way of correcting CD bias was proposed, it has not been argued how to correct the inaccuracy arising from pattern asymmetry using CD-SEM. In this study we will propose how to quantify and correct the measurement inaccuracy affected by pattern asymmetry.

  20. Alternative SEM techniques for observing pyritised fossil material.

    Science.gov (United States)

    Poole; Lloyd

    2000-11-01

    Two scanning electron microscopy (SEM) electron-specimen interactions that provide images based on sample crystal structure, electron channelling and electron backscattered diffraction, are described. The SEM operating conditions and sample preparation are presented, followed by an example application of these techniques to the study of pyritised plant material. The two approaches provide an opportunity to examine simultaneously, at higher magnifications normally available optically, detailed specimen anatomy and preservation state. Our investigation suggests that whereas both techniques have their advantages, the electron channelling approach is generally more readily available to most SEM users. However, electron backscattered diffraction does afford the opportunity of automated examination and characterisation of pyritised fossil material.

  1. A SEM study of the reindeer sinus worm (Linguatula arctica

    Directory of Open Access Journals (Sweden)

    Sven Nikander

    2009-01-01

    Full Text Available Pentastomids are a group of peculiar parasitic arthropods, often referred to as tongue worms due to the resemblance of some species to a tongue. Linguatula arctica is the sinus worm of the reindeer (Rangifer tarandus, being the only pentastomid to have a direct life cycle and an ungulate as a definite host. Here, the surface structures and internal anatomy of adult L. arctica are described as seen by scanning electron microscopy (SEM. Sinus worms were collected in the winter 1991-92 in Finnish Lapland. Paranasal cavities of about 80 reindeer were examined and 30 sinus worms were found. The sinus worms had typical Linguatula sp. morphology, being paddle-shaped, transparent, pale yellow, dorsoventrally flattened and pseudosegmented with a long tapering end. Present at the anteroventral part of the cephalothorax was an oral opening with a large, conspicuous, head-like papillar structure. Bilaterally, on both sides of this opening, was a pair of strong curved hooks. The cephalothorax and abdomen had a segmented appearance, as they showed distinct annulation. There was a small cup-shaped sensory organ present at the lateral margin on each annula. The posterior edge of each annula was roughened by tiny spines projecting backwards. Throughout the cuticular surface, small, circular depressions that represented the apical portion of chloride cells. The genital opening of the male was located medioventrally between the tips of the posterior pair of hooks, and that of the female posteroventrally and subterminally. In both sexes, the genital opening was bilaterally flanked by papillar (in males or leaf-like (in females structures. One copulating couple was present, with the male attached to the posteroventral part of the female with its anteroventral hooks and papillae. Several structures typical of arthropods and other pentastomids were identified. Because SEM allows only surfaces to be studied, the morphology and especially the sense organs of L. arctica

  2. Study on surface properties of gilt-bronze artifacts, after Nd:YAG laser cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeyoun [Division of Restoration Technology, National Research Institute of Cultural Heritage, Daejeon (Korea, Republic of); Cho, Namchul, E-mail: nam1611@hanmail.net [Department of Cultural Heritage Conservation Science, Kongju National University, Gongju, 314-701 (Korea, Republic of); Lee, Jongmyoung [Laser Engineering Group, IMT Co. Ltd, Gyeonggi (Korea, Republic of)

    2013-11-01

    As numerous pores are formed at plating gilt-bronze artifacts, the metal underlying the gold is corroded and corrosion products are formed on layer of gold. Through this study, the surfaces of gilt-bronze are being investigated before and after the laser irradiation to remove corrosion products of copper by using Nd:YAG laser. For gilt-bronze specimens, laser and chemical cleaning were performed, and thereafter, surface analysis with SEM-EDS, AFM, and XPS were used to determine the surface characteristics. Experimental results show that chemical cleaning removes corrosion products of copper through dissolution but it was not removed uniformly and separated the metal substrate and the gold layer. Nevertheless, through laser cleaning, some of the corrosions were removed with some damaged areas due to certain conditions and brown residues remained. Brown residues were copper corrosion products mixed with soil left within the gilt layer. It was due to surface morphology of uneven and rough gilt layer. Hence, they did not react effectively to laser beams, and thus, remained as residues. The surface properties of gilt-bronze should be thoroughly investigated with various surface analyses to succeed in laser cleaning without damages or residues.

  3. Microstructural characterization of the -TiAl alloy samples fabricated by direct laser fabrication rapid prototype technique

    Indian Academy of Sciences (India)

    D Srivastava

    2002-12-01

    A direct laser fabrication technique (DLF) has been used to fabricate near net shape samples of a -TiAl alloy using gas atomized Ti48A148Mn2Nb2 alloy powder as a feed stock material. The microstructures of these Ti48Al48Mn2Nb2 laser treated samples have been characterized using optical, scanning (SEM) and transmission electron microscopy (TEM), both immediately after laser fabrication and after heat treatments. The microstructural studies have shown that the microstructure is heterogeneous in nature and extremely fine in comparison with the conventionally processed material. The process parameters such as laser power and laser scanning speed greatly influence the morphology and the microstructure of the laser treated samples. Heat treatments for a number of process conditions have been carried out to examine the stability of the microstructure which remains stable up to 973 K and rapid grain coarsening occurs at 1273 K. A fully recrystallized and uniform microstructure is obtained after annealing at 1073 K for 24 h and compositional heterogeneity present in the laser-fabricated samples is eliminated. Annealing in the phase field followed by air cooling and annealing in (2 + ) phase region gives rise to a homogeneous and uniform microstructure. However, the microstructure is much coarser than the microstructure of the DLF samples.

  4. Morphological changes of dental hard tissues irradiated by Er:YAG laser with different parameters:an in vitro study%不同参数的Er:YAG激光离体牙窝洞预备的形态学观察

    Institute of Scientific and Technical Information of China (English)

    杨文东; 李倩; 王威; 马林; 郭春岚; 张欣; 龚卓; 赵继志

    2014-01-01

    目的:观察Er:YAG激光对离体人牙进行窝洞预备后的形态学改变,比较不同的能量设置及不同的水气比作用下的预备效果。方法:将10个无龋的离体磨牙随机分为5组(n=2),分别用不同Er:YAG激光参数进行窝洞预备。扫描电镜下观察牙釉质和牙本质的形态学改变。结果:经Er:YAG激光照射后,牙釉质呈现出一个粗糙不平的表面,牙本质层清洁,小管开放。在总功率相近的情况下,当水冷却降到50%或切割牙釉质时脉冲能量增加到700 mJ、切割牙本质时脉冲能量增加到400 mJ时,牙釉质及牙本质表面可发生部分熔融改变。结论:Er:YAG激光使用合适的参数进行牙体硬组织的切割安全有效,但在功率相近的情况下,水冷却不足或能量过大(牙釉质>700 mJ,牙本质>400 mJ)可损伤牙体组织。%AIM To observe the morphological changes of dental hard tissues irradiated by Er:YAG laserwith different parameters .METHODS:10 extracted caries-free human molars were randomly divided into 5 groups(n =2)and were prapred by Er:YAG laser with 200 mJ/40 Hz/8 W/100%water for enamel and 100mJ/40Hz/4W/100%water for dentin(group 1).400 mJ/20 Hz/8 W/100%water for enamel and 200 mJ/20 Hz/4W/100%water fordentin(group 2).400 mJ/20 Hz/8 W/50%water for enamel and 200 mJ/20 Hz/4 W/50%water for dentin(group3).400 mJ/20 Hz/8 W/100% water for enamel and 300 mJ/15 Hz/4.5 W/100% water for dentin (group4 ).700 mJ/10 Hz/7W/100%water for enamel and 400 mJ/10 Hz/4 W/100% water for dentin(group 5),respectively.After preparation,the samples were observed under SEM.RESULTS:The enamel showed a clear rough surface aftertreatment,the dentin showed open dentinal tubules and no smear layer.But when water spray decreased to 50% or thepulse energy increased to 700 mJ for enamel and 400 mJ for dentin,melting areas were detected.CONCLUSION:Appropriate parameters of Er:YAG laser is safe and effective for

  5. Electrochemical and pitting corrosion resistance of AISI 4145 steel subjected to massive laser shock peening treatment with different coverage layers

    Science.gov (United States)

    Lu, J. Z.; Han, B.; Cui, C. Y.; Li, C. J.; Luo, K. Y.

    2017-02-01

    The effects of massive laser shock peening (LSP) treatment with different coverage layers on residual stress, pitting morphologies in a standard corrosive solution and electrochemical corrosion resistance of AISI 4145 steel were investigated by pitting corrosion test, potentiodynamic polarisation test, and SEM observations. Results showed massive LSP treatment can effectively cause an obvious improvement of pitting corrosion resistance of AISI 4145 steel, and increased coverage layer can also gradually improve its corrosion resistance. Massive LSP treatment with multiple layers was shown to influence pitting corrosion behaviour in a standard corrosive solution.

  6. Effect of substrate temperature on microstructural and optical properties of ZnO films grown by pulsed laser deposition

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    ZnO thin films were deposited on n-Si (111) at various substrate temperatures by pulsed laser deposition (PLD).X-ray diffraction (XRD), photoluminescence (PL), Fourier transform infrared spectrophotometer (FTIR), and scanning electron microscopy (SEM) were used to analyze the structure, morphology, and optical property of the ZnO thin films. An optimal crystallized ZnO thin film was obtained at the substrate temperature of 600℃. A blue shift was found in PL spectra due to size confinement effect as the grain sizes decreased. The surfaces of the ZnO thin films were more planar and compact as the substrate temperature increased.

  7. Obtention of TiO{sub 2} thin films by laser ablation; Obtencion de peliculas delgadas de TiO{sub 2} por ablacion laser

    Energy Technology Data Exchange (ETDEWEB)

    Escobar A, L. [Departmaneto de Fisica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, C.P. 11801, Mexico, D.F. (Mexico); Haro P, E.; Camacho L, M.A.; Fernandez G, M.; Jimenez J, J.; Sanchez P, A. [Departamento de Fisica, Universidad Autonoma Metropolitana Iztapalapa, Apdo. Postal 55-532, C.P. 09340 Mexico D.F. (Mexico)

    1998-12-31

    The thin films of TiO{sub 2} have been investigated extensively in the last years, since they have a broad variety of applications, which owing to their less usual chemical, electrical and optical properties. In this work are presented the obtained results to deposit TiO{sub 2} thin films over glass substrates utilizing the Laser ablation technique. It has been deposited thin films at different substrate temperatures and different oxygen pressures, with the purpose to study the influence of these deposit parameters in the structural characteristics of the obtained films. The structural characterization was realized through Raman spectroscopy and X-ray diffraction (XRD), the superficial morphology was verified by Scanning Electron Microscopy (SEM). The results show that the obtained films were TiO{sub 2} in rutile phase, getting this with the substrates at low temperature, its morphology shows a soft surface with some sprinkling particles and a good adherence. (Author)

  8. Synthesis and characterization of titanium dioxide thin films deposited by laser ablation; Sintesis y caracterizacion de peliculas delgadas de TiO{sub 2} depositadas por ablacion laser

    Energy Technology Data Exchange (ETDEWEB)

    Escobar A, L.; Camps C, E.; Falcon B, T.; Carapia M, L.; Haro P, E.; Camacho L, M.A. [Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, C.P. 11801 Mexico D.F. (Mexico)

    2000-07-01

    In this work are presented the results obtained when TiO{sub 2} thin films were deposited using the laser ablation technique. Thin films were deposited at different substrate temperatures, and different oxygen pressures, with the purpose of studying the influence of this deposit parameters in the structural characteristics of the films obtained. The structural characterization was realized through Raman Spectroscopy and X-ray Diffraction (XRD), the surface morphology of the layers deposited was verified by Scanning Electron Microscopy (Sem). The results show that the films obtained are of TiO{sub 2} in rutile phase, getting this at low substrate temperatures, its morphology shows a soft surface with some spattered particles and good adherence. (Author)

  9. Femtosecond pulsed laser ablation of dental hard tissues with numerical control: a roughness and morphology study%飞秒激光切削牙齿硬组织表面粗糙度和显微形貌观察

    Institute of Scientific and Technical Information of China (English)

    孙玉春; Anatoliy Vorobyev; 刘晶; Chunlei Guo; 吕培军

    2012-01-01

    Objective To establish the femtosecond laser experimental platform in vitro for numerical controlled cavity preparation,and to evaluate the roughness quantitatively and observe the microscopic morphology of the cutting surface.Methods Enamel and dentin planes were prepared on human third molars.A universal motion controller was used to control the samples to do rectangle wave motion perpendicular to the incident direction of the laser at focus. The surface roughness was obeerved with confocal laser scanning microscope.Results Precise ablation of the dental hard tissues can be achieved with the established femtosecond laser numerical control platform. For enamel,the surface roughness of the cavity inside laser scanning line was 7.173 μm at the bottom and 2.675 μm on the wall of the cavity.The surface roughness of the cavity between laser scanning lines was 13.667 pm at the bottom and 33.927 μm on the wall.For dentin,the surface roughness of the cavity bottom was 51.182 pm and 25.629 μm for the wall.Scanning electron microscope images showed no micro-cracks or carbonization on enamel,while carbonization,cracks and a small amount of crystalline particles were observed on dentin.Conclusions Precise tooth preparation can be achieved with femtosecond laser numerical control flatform.The surface roughness of cavity wall was less than that of the bottom and can meet the clinical needs.Suitable femtosecond laser output power should be set for different cutting objects,otherwise it may result in tissue damages.%目的 初步建立飞秒激光数控切削牙齿硬组织模拟实验平台并观察显微形貌,以期为飞秒激光的临床应用提供依据.方法 用人离体第三磨牙制备牙釉质和牙本质平面样本各1个;通用运动控制器控制样本在与激光入射方向垂直的焦点平面内做矩形波轨迹运动.激光扫描共聚焦显微镜测量切削面粗糙度,扫描电镜观察显微形貌.结果 用实验建立的飞秒激光数控切

  10. Quantitative approach on SEM images of microstructure of clay soils

    Institute of Scientific and Technical Information of China (English)

    施斌; 李生林; M.Tolkachev

    1995-01-01

    The working principles of Videolab Image Processing System (VIPS), the examining methods of orientation of microstructural units of clay soils and analysing results on SEM images of some typical microstructures of clay soils using the VIPS are introduced.

  11. semPLS: Structural Equation Modeling Using Partial Least Squares

    Directory of Open Access Journals (Sweden)

    Armin Monecke

    2012-05-01

    Full Text Available Structural equation models (SEM are very popular in many disciplines. The partial least squares (PLS approach to SEM offers an alternative to covariance-based SEM, which is especially suited for situations when data is not normally distributed. PLS path modelling is referred to as soft-modeling-technique with minimum demands regarding mea- surement scales, sample sizes and residual distributions. The semPLS package provides the capability to estimate PLS path models within the R programming environment. Different setups for the estimation of factor scores can be used. Furthermore it contains modular methods for computation of bootstrap confidence intervals, model parameters and several quality indices. Various plot functions help to evaluate the model. The well known mobile phone dataset from marketing research is used to demonstrate the features of the package.

  12. MORPHOLOGY OF BLACK CARBON AEROSOLS AND UBIQUITY OF 50-NANOMETER BLACK CARBON AEROSOLS IN THE ATMOSPHERE

    Institute of Scientific and Technical Information of China (English)

    Fengfu Fu; Liangjun Xu; Wei Ye; Yiquan Chen; Mingyu Jiang; Xueqin Xu

    2006-01-01

    Different-sized aerosols were collected by an Andersen air sampler to observe the detailed morphology of the black carbon (BC) aerosols which were separated chemically from the other accompanying aerosols, using a Scanning Electron Microscope equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDX). The results indicate that most BC aerosols are spherical particles of about 50 nm in diameter and with a homogeneous surface. Results also show that these particles aggregate with other aerosols or with themselves to form larger agglomerates in the micrometer range. The shape of these 50-nm BC spherical particles was found to be very similar to that of BC particles released from petroleum-powered vehicular internal combustion engines. These spherical BC particles were shown to be different from the previously reported fullerenes found using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF-MS).

  13. Morphological characteristics, oxidative stability and enzymic hydrolysis of amylose-fatty acid complexes.

    Science.gov (United States)

    Marinopoulou, Anna; Papastergiadis, Efthimios; Raphaelides, Stylianos N; Kontominas, Michael G

    2016-05-05

    Complexes of amylose with fatty acids varying in carbon chain length and degree of unsaturation were prepared at 30, 50 or 70°C by dissolving amylose in 0.1N KOH and mixing with fatty acid potassium soap solution. The complexes were obtained in solid form as precipitates after neutralization. SEM microscopy revealed that the morphology of the complexes was that of ordered lamellae separated from amorphous regions whereas confocal laser scanning microscopy showed images of the topography of the guest molecules in the complex matrix. FTIR spectroscopy revealed that the absorption peak attributed to carbonyl group of free fatty acid was shifted when the fatty acid was in the form of amylose complex. Thermo-gravimetry showed that the unsaturated fatty acids were effectively protected from oxidation when they were complexed with amylose whereas enzymic hydrolysis experiments showed that the guest molecules were quantitatively released from the amylose complexes.

  14. DETECTION OF DELAMINATION IN A COMPOSITE PLATE BY SEM

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A numerical method of integration of Green's functi ons of strip element method (SEM) is proposed. The response of ultrasonic sourc e generated by a transducer on the surface of a multi-ply composite plate conta ining a delamination is analyzed by the use of SEM. The numerical results show that the scanning features of the ultrasonic waves may be used to identify the d elamination inside the composite plate .

  15. Au-C allotrope nano-composite films at extreme conditions generated by intense ultra-short laser

    Science.gov (United States)

    Khan, Saif A.; Saravanan, K.; Tayyab, M.; Bagchi, S.; Avasthi, D. K.

    2016-07-01

    Structural evolution of gold-carbon allotrope nano-composite films under relativistically intense, ultra-short laser pulse irradiation is studied in this work. Au-C nano-composite films, having 4 and 10 at.% of Au, were deposited by co-sputtering technique on silicon substrates. Au-C60 NC films with 2.5 at.% Au were deposited on 12 μm thick Al foil using co-evaporation technique. These samples were radiated with single pulse from 45 fs, 10 TW Ti:Sapphire Laser at RRCAT at an intensity of 3 × 1018 W cm-2. The morphological and compositional changes were investigated using scanning electron microscopy (SEM) and Rutherford back-scattering spectrometry (RBS) techniques. Laser pulse created three morphologically distinct zones around the point of impact on samples with silicon substrates. The gold content in 600 μm circular region around a point of impact is found to reduce by a factor of five. Annular rings of ∼70 nm in diameter were observed in case of Au-C NC film after irradiation. Laser pulse created a hole of about 400 μm in the sample with Al foil as substrate and wavy structures of 6 μm wavelength are found to be created around this hole. The study shows radial variation in nano-structure formation with varying local intensity of laser pulse.

  16. Au–C allotrope nano-composite films at extreme conditions generated by intense ultra-short laser

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Saif A., E-mail: khansaifahmad@gmail.com [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Saravanan, K. [Department of Physics, Tamkang University, Tamsui 251, Taiwan (China); Tayyab, M.; Bagchi, S. [Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Avasthi, D.K. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Amity University, Noida 201313, Uttar Pradesh (India)

    2016-07-15

    Structural evolution of gold–carbon allotrope nano-composite films under relativistically intense, ultra-short laser pulse irradiation is studied in this work. Au–C nano-composite films, having 4 and 10 at.% of Au, were deposited by co-sputtering technique on silicon substrates. Au–C{sub 60} NC films with 2.5 at.% Au were deposited on 12 μm thick Al foil using co-evaporation technique. These samples were radiated with single pulse from 45 fs, 10 TW Ti:Sapphire Laser at RRCAT at an intensity of 3 × 10{sup 18} W cm{sup −2}. The morphological and compositional changes were investigated using scanning electron microscopy (SEM) and Rutherford back-scattering spectrometry (RBS) techniques. Laser pulse created three morphologically distinct zones around the point of impact on samples with silicon substrates. The gold content in 600 μm circular region around a point of impact is found to reduce by a factor of five. Annular rings of ∼70 nm in diameter were observed in case of Au–C NC film after irradiation. Laser pulse created a hole of about 400 μm in the sample with Al foil as substrate and wavy structures of 6 μm wavelength are found to be created around this hole. The study shows radial variation in nano-structure formation with varying local intensity of laser pulse.

  17. fs- and ns-laser processing of polydimethylsiloxane (PDMS) elastomer: Comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Stankova, N.E., E-mail: nestankova@yahoo.com [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Shose, Sofia 1784 (Bulgaria); Atanasov, P.A.; Nedyalkov, N.N.; Stoyanchov, T.R. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Shose, Sofia 1784 (Bulgaria); Kolev, K.N.; Valova, E.I.; Georgieva, J.S.; Armyanov, St.A. [Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria); Amoruso, S.; Wang, X.; Bruzzese, R. [CNR-SPIN, Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Grochowska, K.; Śliwiński, G. [Photophysics Department, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St., 80-231 Gdańsk (Poland); Baert, K.; Hubin, A. [Vrije Universiteit Brussels, Faculty of Engineering, Research group, SURF “Electrochemical and Surface Engineering” (Belgium); Delplancke, M.P.; Dille, J. [Université Libre de Bruxelles, Materials Engineering, Characterization, Synthesis and Recycling (Service 4MAT), Faculté des Sciences Appliquées, 1050 Brussels (Belgium)

    2015-05-01

    Highlights: • fs- and ns-laser (266 and 532 nm) processing of PDMS-elastomer, in air, is studied. • High definition tracks (on the PDMS-elastomer surface) for electrodes are produced. • Selective Pt or Ni metallization of the tracks is produced via electroless plating. • Irradiated and metallized tracks are characterized by μ-Raman spectrometry and SEM. • DC resistance of Pt and Ni tracks is always between 0.5 and 15 Ω/mm. - Abstract: Medical grade polydimethylsiloxane (PDMS) elastomer is a widely used biomaterial as encapsulation and/or as substrate insulator carrier for long term neural implants because of its remarkable properties. Femtosecond (λ = 263 and 527 nm) and nanosecond (266 and 532 nm) laser processing of PDMS-elastomer surface, in air, is investigated. The influence of different processing parameters, including laser wavelength, pulse duration, fluence, scanning speed and overlapping of the subsequent pulses, on the surface activation and the surface morphology are studied. High definition tracks and electrodes are produced. Remarkable alterations of the chemical composition and structural morphology of the ablated traces are observed in comparison with the native material. Raman spectra illustrate well-defined dependence of the chemical composition on the laser fluence, pulse duration, number of pulses and wavelength. An extra peak about ∼512–518 cm{sup −1}, assigned to crystalline silicon, is observed after ns- or visible fs-laser processing of the surface. In all cases, the intensities of Si−O−Si symmetric stretching at 488 cm{sup −1}, Si−CH{sub 3} symmetric rocking at 685 cm{sup −1}, Si−C symmetric stretching at 709 cm{sup −1}, CH{sub 3} asymmetric rocking + Si−C asymmetric stretching at 787 cm{sup −1}, and CH{sub 3} symmetric rocking at 859 cm{sup −1}, modes strongly decrease. The laser processed areas are also analyzed by SEM and optical microscopy. Selective Pt or Ni metallization of the laser processed

  18. 3D nanostructure reconstruction based on the SEM imaging principle, and applications.

    Science.gov (United States)

    Zhu, Fu-Yun; Wang, Qi-Qi; Zhang, Xiao-Sheng; Hu, Wei; Zhao, Xin; Zhang, Hai-Xia

    2014-05-09

    This paper addresses a novel 3D reconstruction method for nanostructures based on the scanning electron microscopy (SEM) imaging principle. In this method, the shape from shading (SFS) technique is employed, to analyze the gray-scale information of a single top-view SEM image which contains all the visible surface information, and finally to reconstruct the 3D surface morphology. It offers not only unobstructed observation from various angles but also the exact physical dimensions of nanostructures. A convenient and commercially available tool (NanoViewer) is developed based on this method for nanostructure analysis and characterization of properties. The reconstruction result coincides well with the SEM nanostructure image and is verified in different ways. With the extracted structure information, subsequent research of the nanostructure can be carried out, such as roughness analysis, optimizing properties by structure improvement and performance simulation with a reconstruction model. Efficient, practical and non-destructive, the method will become a powerful tool for nanostructure surface observation and characterization.

  19. Field emission scanning electron microscopy (FE-SEM) as an approach for nanoparticle detection inside cells.

    Science.gov (United States)

    Havrdova, M; Polakova, K; Skopalik, J; Vujtek, M; Mokdad, A; Homolkova, M; Tucek, J; Nebesarova, J; Zboril, R

    2014-12-01

    When developing new nanoparticles for bio-applications, it is important to fully characterize the nanoparticle's behavior in biological systems. The most common techniques employed for mapping nanoparticles inside cells include transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). These techniques entail passing an electron beam through a thin specimen. STEM or TEM imaging is often used for the detection of nanoparticles inside cellular organelles. However, lengthy sample preparation is required (i.e., fixation, dehydration, drying, resin embedding, and cutting). In the present work, a new matrix (FTO glass) for biological samples was used and characterized by field emission scanning electron microscopy (FE-SEM) to generate images comparable to those obtained by TEM. Using FE-SEM, nanoparticle images were acquired inside endo/lysosomes without disruption of the cellular shape. Furthermore, the initial steps of nanoparticle incorporation into the cells were captured. In addition, the conductive FTO glass endowed the sample with high stability under the required accelerating voltage. Owing to these features of the sample, further analyses could be performed (material contrast and energy-dispersive X-ray spectroscopy (EDS)), which confirmed the presence of nanoparticles inside the cells. The results showed that FE-SEM can enable detailed characterization of nanoparticles in endosomes without the need for contrast staining or metal coating of the sample. Images showing the intracellular distribution of nanoparticles together with cellular morphology can give important information on the biocompatibility and demonstrate the potential of nanoparticle utilization in medicine.

  20. Tin amalgam mirrors: investigation by XRF, SEM-EDS, XRD and EPMA-WDS mapping

    Science.gov (United States)

    Arizio, E.; Orsega, E. F.; Sommariva, G.; Falcone, R.

    2013-06-01

    Ancient mirrors were constituted by a tin-mercury amalgam layer superimposed to a glass sheet. This was the only one method used until the nineteenth century, when the wet silvering process was invented. The tin amalgam is a binary alloy of tin and mercury constituted by two different phases: a mercury-rich liquid phase and a tin-rich solid phase. The amalgam alteration produces mercury loss and a general growth of the solid crystalline phase. In addition, tin dioxide and monoxide are formed with a consequent decrease of the amalgam adhesion to the glass. These degradation phenomena led to reduction or disappearance of the mirror reflective power. The aim of this study was the characterization of the amalgam layers of eight mirror samples dating during the seventeenth and nineteenth centuries. The samples were analyzed by X-ray diffraction and by a Scanning Electron Microscope with an Energy Dispersive Spectrometer (SEM-EDS), and for the first time on this type of alloy by X-ray Fluorescence and EPMA-WDS (Electron Probe Micro Analysis with Wavelength Dispersive Spectrometry) elemental mapping. The contents of tin, mercury, and some trace elements in the amalgam layers have been determined. The investigation of the superficial patterns of the amalgam by SEM, EPMA-WDS mapping, and SEM-EDS allowed a first understanding of some morphologies and processes of the degradation of the amalgam layer.

  1. Scanning electron microscopy of food-poisoning bacterium Bacillus cereus using a variable-pressure SEM.

    Science.gov (United States)

    Nishimura, Masako; Wada, Masao; Akiba, Tsuneo; Yamada, Mitsuhiko

    2003-01-01

    A variable-pressure scanning electron microscopy (VP-SEM) with a cooling stage permits long hours of observation of water-containing specimens in their natural or close to natural state, without the conventional specimen preparations of fixation, dehydration, drying and metal coating. It reduces water vaporization and beam damage by keeping the specimens at a low temperature. We observed Bacillus cereus colonies on nutrient agar, which would shrink significantly if any conventional specimen preparation technique were used. We also studied the growing process of the bacteria on raw and steamed rice using the VP-SEM without conventional preparation techniques. Original specimens were directly mounted onto specimen holders and their backscattered electron images observed under the following conditions: specimen stage temperature, -10 degrees C; specimen chamber vacuum level, 30-70 Pa; and accelerating voltage, 15-20 kV. We recognized that the VP-SEM minimized deformation of the colonies due to shrinkage of the nutrient agar, and successfully imaged the morphology of the colonies and bacteria without a decline in bacteria number, which is apt to occur during fixation and dehydration. Also, the growth process of the bacteria on raw or steamed rice could be observed promptly, since there is no specimen preparation step.

  2. In Vitro effect of low-level laser therapy on typical oral microbial biofilms.

    Science.gov (United States)

    Basso, Fernanda G; Oliveira, Camila F; Fontana, Amanda; Kurachi, Cristina; Bagnato, Vanderlei S; Spolidório, Denise M P; Hebling, Josimeri; de Souza Costa, Carlos A

    2011-01-01

    The aim of this study was to evaluate the effect of specific parameters of low-level laser therapy (LLLT) on biofilms formed by Streptococcus mutans, Candida albicans or an association of both species. Single and dual-species biofilms--SSB and DSB--were exposed to laser doses of 5, 10 or 20 J/cm(2) from a near infrared InGaAsP diode laser prototype (LASERTable; 780 ± 3 nm, 0.04 W). After irradiation, the analysis of biobilm viability (MTT assay), biofilm growth (cfu/mL) and cell morphology (SEM) showed that LLLT reduced cell viability as well as the growth of biofilms. The response of S. mutans (SSB) to irradiation was similar for all laser doses and the biofilm growth was dose dependent. However, when associated with C. albicans (DSB), S. mutans was resistant to LLLT. For C. albicans, the association with S. mutans (DSB) caused a significant decrease in biofilm growth in a dose-dependent fashion. The morphology of the microorganisms in the SSB was not altered by LLLT, while the association of microbial species (DSB) promoted a reduction in the formation of C. albicans hyphae. LLLT had an inhibitory effect on the microorganisms, and this capacity can be altered according to the interactions between different microbial species.

  3. Intraoral laser welding: ultrastructural and mechanical analysis to compare laboratory laser and dental laser.

    Science.gov (United States)

    Fornaini, Carlo; Passaretti, Francesca; Villa, Elena; Rocca, Jean-Paul; Merigo, Elisabetta; Vescovi, Paolo; Meleti, Marco; Manfredi, Maddalena; Nammour, Samir

    2011-07-01

    The Nd:YAG laser has been used since 1970 in dental laboratories to weld metals on dental prostheses. Recently in several clinical cases, we have suggested that the Nd:YAG laser device commonly utilized in the dental office could be used to repair broken fixed, removable and orthodontic prostheses and to weld metals directly in the mouth. The aim of this work was to evaluate, using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and dynamic mechanical analysis (DMA), the quality of the weld and its mechanical strength, comparing a device normally used in dental laboratory and a device normally used in the dental office for oral surgery, the same as that described for intraoral welding. Metal plates of a Co-Cr-Mo dental alloy and steel orthodontic wires were subjected to four welding procedures: welding without filler metal using the laboratory laser, welding with filler metal using the laboratory laser, welding without filler metal using the office laser, and welding with filler metal using the office laser. The welded materials were then analysed by SEM, EDS and DMA. SEM analysis did not show significant differences between the samples although the plates welded using the office laser without filler metal showed a greater number of fissures than the other samples. EDS microanalysis of the welding zone showed a homogeneous composition of the metals. Mechanical tests showed similar elastic behaviours of the samples, with minimal differences between the samples welded with the two devices. No wire broke even under the maximum force applied by the analyser. This study seems to demonstrate that the welds produced using the office Nd:YAG laser device and the laboratory Nd:YAG laser device, as analysed by SEM, EDS and DMA, showed minimal and nonsignificant differences, although these findings need to be confirmed using a greater number of samples.

  4. Wear behaviors of HVOF sprayed WC-12Co coatings by laser remelting under lubricated condition

    Science.gov (United States)

    Dejun, Kong; Tianyuan, Sheng

    2017-03-01

    A HVOF (high velocity oxygen fuel) sprayed WC-12Co coating was remelted with a CO2 laser. The surface-interface morphologies and phases were analyzed by means of SEM (scanning electron microscopy), and XRD (X-ray diffraction), respectively. The friction and wear behaviors of WC-12Co coating under the dry and lubricated conditions were investigated with a wear test. The morphologies and distributions of chemical elements on worn scar were analyzed with a SEM, and its configured EDS (energy diffusive spectrometer), respectively, and the effects of lubricated condition on COFs (coefficient of friction) and wear performance were also discussed. The results show that the adhesion between the coating and the substrate is stronger after laser remetling (LR), in which mechanical bonding, accompanying with metallurgical bonding, was found. At the load of 80 N, the average COF under the dry and lubricated friction conditions is 0.069, and 0.052, respectively, the latter lowers by 23.3% than the former, and the wear rate under the lubricated condition decreases by 302.3% than that under the dry condition. The wear mechanism under the dry and lubrication conditions is primarily composed of abrasive wear, cracking, and fatigue failure.

  5. Porous niobium coatings fabricated with selective laser melting on titanium substrates: Preparation, characterization, and cell behavior.

    Science.gov (United States)

    Zhang, Sheng; Cheng, Xian; Yao, Yao; Wei, Yehui; Han, Changjun; Shi, Yusheng; Wei, Qingsong; Zhang, Zhen

    2015-08-01

    Nb, an expensive and refractory element with good wear resistance and biocompatibility, is gaining more attention as a new metallic biomaterial. However, the high price of the raw material, as well as the high manufacturing costs because of Nb's strong oxygen affinity and high melting point have limited the widespread use of Nb and its compounds. To overcome these disadvantages, porous Nb coatings of various thicknesses were fabricated on Ti substrate via selective laser melting (SLM), which is a 3D printing technique that uses computer-controlled high-power laser to melt the metal. The morphology and microstructure of the porous Nb coatings, which had pores ranging from 15 to 50 μm in size, were characterized with scanning electron microscopy (SEM). The average hardness of the coating, which was measured with the linear intercept method, was 392±37 HV. In vitro tests of the porous Nb coating which was monitored with SEM, immunofluorescence, and CCK-8 counts of cells, exhibited excellent cell morphology, attachment, and growth. The simulated body fluid test also proved the bioactivity of the Nb coating. Therefore, these new porous Nb coatings could potentially be used for enhanced early biological fixation to bone tissue. In addition, this study has shown that SLM technique could be used to fabricate coatings with individually tailored shapes and/or porosities from group IVB and VB biomedical metals and their alloys on stainless steel, Co-Cr, and other traditional biomedical materials without wasting raw materials.

  6. FIB-SEM cathodoluminescence tomography: practical and theoretical considerations.

    Science.gov (United States)

    De Winter, D A M; Lebbink, M N; Wiggers De Vries, D F; Post, J A; Drury, M R

    2011-09-01

    Focused ion beam-scanning electron microscope (FIB-SEM) tomography is a powerful application in obtaining three-dimensional (3D) information. The FIB creates a cross section and subsequently removes thin slices. The SEM takes images using secondary or backscattered electrons, or maps every slice using X-rays and/or electron backscatter diffraction patterns. The objective of this study is to assess the possibilities of combining FIB-SEM tomography with cathodoluminescence (CL) imaging. The intensity of CL emission is related to variations in defect or impurity concentrations. A potential problem with FIB-SEM CL tomography is that ion milling may change the defect state of the material and the CL emission. In addition the conventional tilted sample geometry used in FIB-SEM tomography is not compatible with conventional CL detectors. Here we examine the influence of the FIB on CL emission in natural diamond and the feasibility of FIB-SEM CL tomography. A systematic investigation establishes that the ion beam influences CL emission of diamond, with a dependency on both the ion beam and electron beam acceleration voltage. CL emission in natural diamond is enhanced particularly at low ion beam and electron beam voltages. This enhancement of the CL emission can be partly explained by an increase in surface defects induced by ion milling. CL emission enhancement could be used to improve the CL image quality. To conduct FIB-SEM CL tomography, a recently developed novel specimen geometry is adopted to enable sequential ion milling and CL imaging on an untilted sample. We show that CL imaging can be manually combined with FIB-SEM tomography with a modified protocol for 3D microstructure reconstruction. In principle, automated FIB-SEM CL tomography should be feasible, provided that dedicated CL detectors are developed that allow subsequent milling and CL imaging without manual intervention, as the current CL detector needs to be manually retracted before a slice can be milled

  7. Evaluation of the permeability and morphological alteration of the dental surface after apicoectomy, treatment and preparation with Er:YAG and Nd:YAG lasers; Avaliacao da permeabilidade e da alteracao morfologica da superficie dentinaria apos apicectomia, tratamento e retropreparo com os lasers de Er:YAG e Nd:YAG

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Rodrigo Guerra de

    2001-07-01

    Group I samples, meanwhile, did not present statistically significantly better results than the control group. Group II presented statistically significantly less infiltration than the other experimental groups. This result is compatible with the morphological and structural alterations evidenced by scanning electron microscopy: the group I samples (Er:YAG) presented clean, irregular surfaces with the presence of some cratering, without a smear layer and with the dental tubules exposed. The group II samples (Er:YAG and Nd:YAG) presented smoother, clean surfaces, without a smear layer, with fusion and resolidification of the dentin which sealed the dental tubules. Under the conditions of the study, apicoectomy with the Er:YAG laser followed by subsequent treatment of the cut surface and resulting cavity with a Nd:YAG laser, have shown as an option capable of reducing the permeability of the dentin to methylene blue dye. (author)

  8. Synthetic laser medium

    Science.gov (United States)

    Stokowski, Stanley E.

    1989-01-01

    A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chormium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

  9. Comparison of tensile bond strengths of four one-bottle self-etching adhesive systems with Er:YAG laser-irradiated dentin.

    Science.gov (United States)

    Jiang, Qianzhou; Chen, Minle; Ding, Jiangfeng

    2013-12-01

    This study aimed to investigate the interaction of current one-bottle self-etching adhesives and Er:YAG laser with dentin using a tensile bond strength (TBS) test and scanning electron microscopy (SEM) in vitro. Two hundred and thirteen dentin discs were randomly distributed to the Control Group using bur cutting and to the Laser Group using an Er:YAG laser (200 mJ, VSP, 20 Hz). The following adhesives were investigated: one two-step total-etch adhesive [Prime & Bond NT (Dentsply)] and four one-step self-etch adhesives [G-Bond plus (GC), XENO V (Dentsply), iBond Self Etch (Heraeus) and Adper Easy One (3 M ESPE)]. Samples were restored with composite resin, and after 24-hour storage in distilled water, subjected to the TBS test. For morphological analysis, 12 dentin specimens were prepared for SEM. No significant differences were found between the control group and laser group (p = 0.899); dentin subjected to Prime & Bond NT, XENOV and Adper Easy One produced higher TBS. In conclusion, this study indicates that Er:YAG laser-prepared dentin can perform as well as bur on TBS, and some of the one-step one-bottle adhesives are comparable to the total-etch adhesives in TBS on dentin.

  10. Attachment and proliferation of human osteoblast-like cells (MG-63) on laser-ablated titanium implant material

    Energy Technology Data Exchange (ETDEWEB)

    Györgyey, Ágnes; Ungvári, Krisztina [Department of Oral Biology and Experimental Dental Research, Faculty of Dentistry, University of Szeged, H-6720 Szeged (Hungary); Kecskeméti, Gabriella; Kopniczky, Judit [Department of Optics and Quantum Electronics, Faculty of Science and Informatics, University of Szeged, H-6720 Szeged (Hungary); Hopp, Béla [Research Group on Laser Physics, Hungarian Academy of Sciences and University of Szeged, H-6720 Szeged (Hungary); Oszkó, Albert [Department of Physical Chemistry and Materials Science, Faculty of Science and Informatics, University of Szeged, H-6720 Szeged (Hungary); Pelsöczi, István; Rakonczay, Zoltán [Department of Oral Biology and Experimental Dental Research, Faculty of Dentistry, University of Szeged, H-6720 Szeged (Hungary); Nagy, Katalin [Department of Oral Surgery, Faculty of Dentistry, University of Szeged, H-6720 Szeged (Hungary); Turzó, Kinga, E-mail: kturzo@yahoo.com [Department of Oral Biology and Experimental Dental Research, Faculty of Dentistry, University of Szeged, H-6720 Szeged (Hungary)

    2013-10-15

    Demand is increasing for shortening the long (3–6 months) osseointegration period to rehabilitate patients' damaged chewing apparatus in as short a time as possible. For dental implants, as for biomaterials in general, the bio- and osseointegration processes can be controlled at molecular and cellular levels by modification of the implant surface. One of the most promising of such surface modifications is laser ablation, as demonstrated by our previous results [46]. Commercially pure (CP4) sand-blasted, acid-etched titanium disks (Denti® System Ltd., Hungary) were irradiated with a KrF excimer laser (248 nm, fluence 0.4 J/cm{sup 2}, FWHM 18 ns, 2000 pulses), or with a Nd:YAG laser (532 nm, 1.3 J/cm{sup 2}, 10 ns, 200 pulses) then examined by SEM, AFM, and XPS. In vitro attachment (24 h) and proliferation (72 h) of MG-63 osteoblast cells were investigated via dimethylthiazol-diphenyl tetrazolium bromide (MTT), alamarBlue (AB) assays alkaline phosphatase quantification (ALP) and SEM. SEM and AFM revealed significant changes in morphology and roughness. XPS confirmed the presence of TiO{sub 2} on each sample; after Nd:YAG treatment a reduced state of Ti (Ti{sup 3+}) was also observed. MTT, AB and ALP measurements detected an increase in the number of cells between the 24- and 72 hour observations; however, laser treatment did not affect cell attachment and proliferation significantly. - Highlights: • CP4 titanium implant surfaces were modified with Nd:YAG and KrF excimer laser. • SEM and AFM revealed significant changes in morphology and roughness. • XPS confirmed the presence of TiO{sub 2} on each sample; after Nd:YAG treatment a reduced state of Ti (Ti{sup 3+}) was found. • Cell proliferation experiments detected an increased number of MG-63 cells between the 24 h and 72 h observations. • Laser treatments neither dist