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Sample records for preparations mechanical polishing

  1. Ultrasmooth gold surfaces prepared by chemical mechanical polishing for applications in nanoscience.

    Science.gov (United States)

    Miller, Michael S; Ferrato, Michael-Anthony; Niec, Adrian; Biesinger, Mark C; Carmichael, Tricia Breen

    2014-12-02

    For over 20 years, template stripping has been the best method for preparing ultrasmooth metal surfaces for studies of nanostructures. However, the organic adhesives used in the template stripping method are incompatible with many solvents, limiting the conditions that may subsequently be used to prepare samples; in addition, the film areas that can be reliably prepared are typically limited to ∼1 cm(2). In this article, we present chemical-mechanical polishing (CMP) as an adhesive-free, scalable method of preparing ultrasmooth gold surfaces. In this process, a gold film is first deposited by e-beam evaporation onto a 76-mm-diameter silicon wafer. The CMP process removes ∼4 nm of gold from the tops of the grains comprising the gold film to produce an ultrasmooth gold surface supported on the silicon wafer. We measured root-mean-square (RMS) roughness values using atomic force microscopy of 12 randomly sampled 1 μm × 1 μm areas on the surface of the wafer and repeated the process on 5 different CMP wafers. The average RMS roughness was 3.8 ± 0.5 Å, which is comparable to measured values for template-stripped gold (3.7 ± 0.5 Å). We also compared the use of CMP and template-stripped gold as bottom electrical contacts in molecular electronic junctions formed from n-alkanethiolate self-assembled monolayers as a sensitive test bed to detect differences in the topography of the gold surfaces. We demonstrate that these substrates produce statistically indistinguishable values for the tunneling decay coefficient β, which is highly sensitive to the gold surface topography.

  2. Substrate preparation by contactless mechanochemical polish

    Science.gov (United States)

    Rotter, S.; Lachish, U.; El-Hanany, U.

    1985-10-01

    A simple, yet effective, polishing technique for substrate preparation is presented. It is contactless chemical polish which does not introduce any defects into the substrate during the process. The method can be readily adopted in all cases where chemical polishing is practical for substrate preparation. Results similar to those obtained by the more sophisticated hydroplaning method can be achieved.

  3. Preparation of Ce-doped colloidal SiO{sub 2} composite abrasives and their chemical mechanical polishing behavior on sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Hong, E-mail: hong_lei2005@aliyun.com [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Research Center of Nano-science and Nano-technology, Shanghai University, Shanghai 200444 (China); Tong, Kaiyu; Wang, Zhanyong [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China)

    2016-04-01

    Chemical mechanical polishing (CMP) has become a widely accepted global planarization technology. Abrasive is one of key elements during CMP process. In order to enhance removal rate and improve surface quality of sapphire substrate, a series of novel Ce-doped colloidal SiO{sub 2} composite abrasives were prepared by chemical co-precipitation method. The CMP performances of the Ce-doped colloidal SiO{sub 2} composite abrasives on sapphire substrate were investigated by using UNIPOL-1502 polishing equipment. The analyses on the surface of polished sapphire substrate indicate that slurries containing the Ce-doped colloidal SiO{sub 2} composite abrasives exhibit lower surface roughness, higher material removal rate than that of pure colloidal SiO{sub 2} abrasive under the same testing conditions. Furthermore, the acting mechanism of the Ce-doped colloidal silica in sapphire CMP was investigated. X-ray photoelectron spectroscopy analysis shows that solid-state chemical reactions between Ce-doped silica abrasives and sapphire surface occur during CMP process, which can promote the chemical effect in CMP and lead to the improvement of material removing rate. - Highlights: • Novel Ce-doped colloidal SiO{sub 2} composite abrasives were prepared. • The chemical mechanical polishing (CMP) performances of the composite abrasives on sapphire substrate were investigated. • Novel composite abrasives show excellent polishing characteristics comparison with pure colloidal SiO{sub 2} abrasive. • We explore and report the acting mechanism of composite abrasives to sapphire CMP.

  4. Preparing polished crystal slices with high precision orientation

    DEFF Research Database (Denmark)

    Mathiesen, S. Ipsen; Gerward, Leif; Pedersen, O.

    1974-01-01

    A polishing procedure is described which utilizes a high precision Laue technique for crystal orientation. Crystal slices with their final polished surfaces parallel to a crystallographic plane within 0.02° can be prepared. ©1974 The American Institute of Physics......A polishing procedure is described which utilizes a high precision Laue technique for crystal orientation. Crystal slices with their final polished surfaces parallel to a crystallographic plane within 0.02° can be prepared. ©1974 The American Institute of Physics...

  5. Chemical mechanical polishing of freestanding GaN substrates

    Institute of Scientific and Technical Information of China (English)

    颜怀跃; 修向前; 刘战辉; 张荣; 华雪梅; 谢自力; 韩平; 施毅; 郑有炓

    2009-01-01

    Chemical mechanical polishing (CMP) has been used to produce smooth and scratch-free surfaces for GaN. In the aqueous solution of KOH, GaN is subjected to etching. At the same time, all surface irregularities, including etch pyramids, roughness after mechanical polishing and so on will be removed by a polishing pad. The experiments had been performed under the condition of different abrasive particle sizes of the polishing pad. Also the polishing results for different polishing times are analyzed, and chemical mechanical polishing resulted in an average root mean square (RMS) surface roughness of 0.565 nm, as measured by atomic force microscopy.

  6. Tribology analysis of chemical-mechanical polishing

    Energy Technology Data Exchange (ETDEWEB)

    Runnels, S.R.; Eyman, L.M. (Sematech, Austin, TX (United States))

    1994-06-01

    To better understand the variation of material removal rate on a wafer during chemical-mechanical polishing (CMP), knowledge of the stress distribution on the wafer surface is required. The difference in wafer-surface stress distributions could be considerable depending on whether or not the wafer hydroplanes during polishing. This study analyzes the fluid film between the wafer and pad and demonstrates that hydroplaning is possible for standard CMP processes. The importance of wafer curvature, slurry viscosity, and rotation speed on the thickness of the fluid film is also demonstrated.

  7. Contribution of ultrasonic traveling wave to chemical-mechanical polishing.

    Science.gov (United States)

    Li, Liang; He, Qing; Zheng, Mian; Liu, Zheng

    2015-02-01

    The ultrasonic vibrators are introduced into the chemical-mechanical polishing devices, and in this polishing system, the ultrasonic vibrators generate ultrasonic traveling wave and keep coaxial with the polished silicon wafer rotating at given speed so as to compare the texture of the polished silicon wafers. And the experiments on the chemical-mechanical polishing with assisted ultrasonic vibration are accomplished in order to investigate the effect of the ultrasonic vibration on the chemical-mechanical polishing. Via comparing the roughness average of the two silicon wafers polished with assisted ultrasonic vibration and without assisted vibration, it is found that the morphology of the silicon wafer polished with assisted vibration is superior to that without assisted vibration, that is, this series of experiments indicate that the ultrasonic vibration is beneficial to the chemical-mechanical polishing. Aiming at understanding the contribution of the ultrasonic vibration to chemical-mechanical polishing in detail, the model of the chemical-mechanical polishing with the assisted ultrasonic vibration is built up, which establishes the relationship of the removal rate and the polishing variables such as the rotary speed of silicon wafers, the amplitude and the frequency of vibrators, the particle density of polishing slurry and the characteristics of polishing pad etc. This model not only could be used to explain the experimental results but also to illuminate the roles played by the polishing variables.

  8. Potentiodynamic behaviour of mechanically polished titanium electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Camara, O.R.; DePauli, C.P.; Giordano, M.C.

    1984-08-01

    The behaviour of titanium electrodes mechanically polished and/or anodically polarized at low positive potential in solutions at constant ionic strength between pH 0.3 and 11.0 is reported. The oxide electroformation potential on a mechanically polished electrode shows a complex dependence on the bulk solution pH. This dependence is similar to that obtained through acid-base titration with titanium as the indicating electrode. The formation of hydroxo-complexes on the spontaneously formed titanium oxide offers a possible explanation for the oxide electroformation potential dependence on pH. Anodic and cathodic wide current peaks are obtained between the potential of the hydrogen evolution and that of the massive oxide electroformation; the corresponding redox system becomes evident at pH 4.0 from the first potentiodynamic cycle. An interpretation of these processes involving the participation of non stoichiometric oxides and hydrogen ions is attempted.

  9. Cation Effect on Copper Chemical Mechanical Polishing

    Institute of Scientific and Technical Information of China (English)

    WANG Liang-Yong; LIU Bo; SONG Zhi-Tang; FENG Song-Lin

    2009-01-01

    We examine the effect of cations in solutions containing benzotriazole (BTA) and H2O2 on copper chemical mechanical polishing (CMP). On the base of atomic force microscopy (AFM) and material removal rate (MRR) results, it is found that ammonia shows the highest MRR as well as good surface after CMP, while KOH demon-strates the worst performance. These results reveal a mechanism that sma//molecules with lone-pairs rather than molecules with steric effect and common inorganic cations are better for copper CMP process, which is indirectly confirmed by open circuit potential (OCP).

  10. Cation Effect on Copper Chemical Mechanical Polishing

    Science.gov (United States)

    Wang, Liang-Yong; Liu, Bo; Song, Zhi-Tang; Feng, Song-Lin

    2009-02-01

    We examine the effect of cations in solutions containing benzotriazole (BTA) and H2O2 on copper chemical mechanical polishing (CMP). On the base of atomic force microscopy (AFM) and material removal rate (MRR) results, it is found that ammonia shows the highest MRR as well as good surface after CMP, while KOH demonstrates the worst performance. These results reveal a mechanism that small molecules with lone-pairs rather than molecules with steric effect and common inorganic cations are better for copper CMP process, which is indirectly confirmed by open circuit potential (OCP).

  11. Copper chemical mechanical polishing using a slurry-free technique

    NARCIS (Netherlands)

    Nguyen, V.H.; Hof, A.J.; Kranenburg, van H.; Woerlee, P.H.; Weimar, F.

    2001-01-01

    A study of the chemical mechanical polishing (CMP) of thin copper films using fixed-abrasive pads is presented. The composition of the polishing solution is optimized by investigating the impact of both the oxidizer concentration and the pH of the solution on the polishing characteristics of copper.

  12. Review on Application of Rare Earth Polishing Powders in Glass Polishing

    Institute of Scientific and Technical Information of China (English)

    Li Xueshun; Yang Guosheng

    2004-01-01

    The paper reviewed different explanations to the mechanism of glass polishing, the practices of glass polishing and the preparation of polishing powders, addressed the growth mechanism of CeO2 crystals, summarized the roles of rare earth elements in glass polishing and the factors that may influence the polishing effects, and specified the existing problems in glass polishing.

  13. Defect centers in chemical-mechanical polished MOS oxides

    Energy Technology Data Exchange (ETDEWEB)

    Shaneyfelt, M.R.; Warren, W.L.; Hetherington, D.L.; Timon, R.P.; Resnick, P.J.; Winokur, P.S.

    1994-12-31

    Defect centers generated in vacuum-ultraviolet irradiated chemical-mechanical polished oxides have been characterized using electron paramagnetic resonance and C-V analysis. Both oxide trap E{sub {gamma}} and interface trap P{sub b0} centers were detected in unpolished and polished oxides. In addition, another interface defect center known as the P{sub b1} center was only identified in the polished oxides, suggesting that the polishing process altered the SiO{sub 2}/Si interface.

  14. Electro-Chemically Enhanced Mechanical Polishing of Nickel Mandrels

    Science.gov (United States)

    Gubarev, Mikhail; Ramsey, Brian; Engelhaupt, Darell

    2006-01-01

    Grinding and mechanical polishing techniques used for x-ray optics mandrel figuring lead to mid-frequency surface ripple. These small figure variations have to be addressed in order to improve the performance of the resulting x-ray mirrors. If the electrochemical etching is combined with mechanical polishing, the figuring and the surface finishing cm be done simultaneously and be used to correct the mid-frequency surface ripple. It is shown that the electrochemical mechanical polishing method allows selective removal of nickel alloy without mandrel surface microroughness degradation.

  15. Electrolyte composition and removal mechanism of Cu electrochemical mechanical polishing

    Institute of Scientific and Technical Information of China (English)

    边燕飞; 翟文杰; 程媛媛; 朱宝全; 王金虎

    2014-01-01

    The optimization of electrolytes and the material removal mechanisms for Cu electrochemical mechanical planarization (ECMP) at different pH values including 5-methyl-1H-benzotriazole (TTA), hydroxyethylidenediphosphoric acid (HEDP), and tribasic ammonium citrate (TAC) were investigated by electrochemical techniques, X-ray photoelectron spectrometer (XPS) analysis, nano-scratch tests, AFM measurements, and polishing of Cu-coated blanket wafers. The experimental results show that the planarization efficiency and the surface quality after ECMP obtained in alkali-based solutions are superior to that in acidic-based solutions, especially at pH=8. The optimal electrolyte compositions (mass fraction) are 6% HEDP, 0.3% TTA and 3% TAC at pH=8. The main factor affecting the thickness of the oxide layer formed during ECMP process is the applied potential. The soft layer formation is a major mechanism for electrochemical enhanced mechanical abrasion. The surface topography evolution before and after electrochemical polishing (ECP) illustrates the mechanism of mechanical abrasion accelerating electrochemical dissolution, that is, the residual stress caused by the mechanical wear enhances the electrochemical dissolution rate. This understanding is beneficial for optimization of ECMP processes.

  16. Study on chemical mechanical polishing of silicon wafer with megasonic vibration assisted.

    Science.gov (United States)

    Zhai, Ke; He, Qing; Li, Liang; Ren, Yi

    2017-09-01

    Chemical mechanical polishing (CMP) is the primary method to realize the global planarization of silicon wafer. In order to improve this process, a novel method which combined megasonic vibration to assist chemical mechanical polishing (MA-CMP) is developed in this paper. A matching layer structure of polishing head was calculated and designed. Silicon wafers are polished by megasonic assisted chemical mechanical polishing and traditional chemical mechanical polishing respectively, both coarse polishing and precision polishing experiments were carried out. With the use of megasonic vibration, the surface roughness values Ra reduced from 22.260nm to 17.835nm in coarse polishing, and the material removal rate increased by approximately 15-25% for megasonic assisted chemical mechanical polishing relative to traditional chemical mechanical polishing. Average Surface roughness values Ra reduced from 0.509nm to 0.387nm in precision polishing. The results show that megasonic assisted chemical mechanical polishing is a feasible method to improve polishing efficiency and surface quality. The material removal and finishing mechanisms of megasonic vibration assisted polishing are investigated too. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. TWO STEPS CHEMICAL-MECHANICAL POLISHING OF RIGID DISK SUBSTRATE TO GET ATOM-SCALE PLANARIZATION SURFACE

    Institute of Scientific and Technical Information of China (English)

    LEI Hong; LUO Jianbin; LU Xinchun

    2006-01-01

    In order to get atomic smooth rigid disk substrate surface, ultra-fined alumina slurry and nanometer silica slurry are prepared, and two steps chemical-mechanical polishing (CMP) of rigid disk substrate in the two slurries are studied. The results show that, during the first step CMP in the alumina slurry, a high material removal rate is reached, and the average roughness (Ra) and the average waviness (Wa) of the polished surfaces can be decreased from previous 1.4 nm and 1.6 nm to about 0.6 nm and 0.7 nm, respectively. By using the nanometer silica slurry and optimized polishing process parameters in the second step CMP, the Ra and the Wa of the polished surfaces can be further reduced to 0.038 nm and 0.06 nm, respectively. Atom force microscopy (AFM) analysis shows that the final polished surfaces are ultra-smooth without micro-defects.

  18. Chemical Mechanical Polishing of Ruthenium, Cobalt, and Black Diamond Films

    Science.gov (United States)

    Peethala, Brown Cornelius

    Ta/TaN bilayer serves as the diffusion barrier as well as the adhesion promoter between Cu and the dielectric in 32 nm technology devices. A key concern of future technology devices (sustain the diffusion barrier performance without forming voids and meeting the requirements of low resistivity. These are very challenging requirements for the Ta/TaN bilayer at a thickness of 50 nm/min) Ru removal rates (RRs) are required and as a stop layer in magnetic recording head fabrication where low (Diamond (BD) is a SiCOH type material with a dielectric constant of ˜2.9 and here, polishing of BD was investigated in order to understand the polishing behavior of SiCOH-based materials using the barrier slurries. The slurries that were developed for polishing Co and Ru in this work and Ta/TaN (earlier) were investigated for polishing the Black Diamond (BD) films. Here, it was found that ionic salts play a major role in enhancing the BD RRs to ˜65 nm/min compared to no removal rates in the absence of additives. A removal mechanism in the presence of ionic salts is proposed.

  19. Tribochemical interaction between nanoparticles and surfaces of selective layer during chemical mechanical polishing

    Energy Technology Data Exchange (ETDEWEB)

    Ilie, Filip, E-mail: filip@meca.omtr.pub.ro [Polytechnic University of Bucharest, Department of Machine Elements and Tribology (Romania)

    2013-11-15

    Nanoparticles have been widely used in polish slurries such as those in the chemical mechanical polishing (CMP) process. For understanding the mechanisms of CMP, an atomic force microscope (AFM) is used to characterize polished surfaces of selective layers, after a set of polishing experiments. To optimize the CMP polishing process, one needs to get information on the interaction between the nano-abrasive slurry nanoparticles and the surface of selective layer being polished. The slurry used in CMP process of the solid surfaces is slurry with large nanoparticle size colloidal silica sol nano-abrasives. Silica sol nano-abrasives with large nanoparticle are prepared and characterized by transmission electron microscopy, particles colloidal size, and Zeta potential in this paper. The movement of nanoparticles in liquid and the interaction between nanoparticles and solid surfaces coating with selective layer are very important to obtain an atomic alloy smooth surface in the CMP process. We investigate the nanoparticle adhesion and removal processes during CMP and post-CMP cleaning. The mechanical interaction between nanoparticles and the wafer surface was studied using a microcontact wear model. This model considers the nanoparticle effects between the polishing interfaces during load balancing. Experimental results on polishing and cleaning are compared with numerical analysis. This paper suggests that during post-CMP cleaning, a combined effort in chemical and mechanical interaction (tribochemical interactions) would be effective in removal of small nanoparticles during cleaning. For large nanoparticles, more mechanical forces would be more effective. CMP results show that the removal rate has been improved to 367 nm/min and root mean square (RMS) of roughness has been reduced from 4.4 to 0.80 nm. Also, the results show that the silica sol nano-abrasives about 100 nm are of higher stability (Zeta potential is −65 mV) and narrow distribution of nanoparticle

  20. Chemical mechanical polishing of tantalum and tantalum nitride

    Science.gov (United States)

    Janjam, Sathish Babu S. V.

    There is a continuing need in the semiconductor industry to clear residual copper (Cu) and planarize the tantalum (Ta)/tantalum nitride (TaN) barrier/etch stop layer with a higher removal rate using the technique of Chemical Mechanical Polishing (CMP). Obtaining high removal rates for Ta/TaN is very challenging as the films are very hard, and hence it is difficult to achieve high Ta/TaN removal rates by just relying on an increase in the mechanical forces (operating pressure) alone during CMP. Ta/TaN is an inert metal, therefore, obtaining high Ta/TaN removal rates by using chemical additives is also challenging. Not only Ta/TaN needs to be removed at a higher rate in the second step of polishing, but also remaining Cu should be cleared. It is important to search for novel chemicals that can form a thin film on the Ta/TaN surface which can be easily abraded by the polishing pad with very less pressure. In this work, oxalic and tartaric acids have been investigated as the complexing agents in slurries for Ta/TaN CMP. Oxalic and tartaric acids appear to be reactive with Ta in the presence of hydrogen peroxide. A dispersion of the Oxalic acid (OA)/Tartaric Acid (TA) - peroxide mixtures with silica (fumed/colloidal) can be used to achieve Ta removal rates that are ˜ 90 nm/min at pH between 3 to 6 by applying a down force of 6.3 psi, where as at a lower down force of 2 psi, a removal rate of ˜ 40 nm/min has been achieved at pH = 3. It was shown earlier that a high Cu removal rate can be obtained using OA-peroxide based slurries with/without the addition of abrasives at pH = 3 [1]. So, in the first step, Cu could be removed at high rates at pH = 3 and by changing the pH to 5 or 6, Ta/TaN can be removed as mentioned above. Hence these slurries could be used as "single dispersion slurries " that could be used for both the first and second steps of Cu CMP. During the second step (barrier layer polish), Cu removal rates are low but not low enough to minimize dishing with

  1. Modeling Chemical Mechanical Polishing with Couple Stress Fluids

    Institute of Scientific and Technical Information of China (English)

    张朝辉; 雒建斌; 温诗铸

    2004-01-01

    Chemical mechanical polishing (CMP) is a manufacturing process used to achieve high levels of global and local planarity.Currently, the slurries used in CMP usually contain nanoscale particles to accelerate the removal ratio and to optimize the planarity, whose rheological properties can no longer be accurately modeled with Newtonian fluids.The Reynolds equation, including the couple stress effects, was derived in this paper.The equation describes the mechanism to solve the CMP lubrication equation with the couple stress effects.The effects on load and moments resulting from the various parameters, such as pivot height, roll angle, and pitch angle, were subsequently simulated.The results show that the couple stress can provide higher load and angular moments.This study sheds some lights into the mechanism of the CMP process.

  2. Chemical Mechanical Polishing of Glass Substrate with α-Alumina-g-Polystyrene Sulfonic Acid Composite Abrasive

    Institute of Scientific and Technical Information of China (English)

    LEI Hong; BU Naijing; ZHANG Zefang; CHEN Ruling

    2010-01-01

    Abrasive is the one of key influencing factors during chemical mechanical polishing(CMP) process. Currently, α-Alumina (α-Al2O3) particle, as a kind of abrasive, has been widely used in CMP slurries, but their high hardness and poor dispersion stability often lead to more surface defects. After being polished with composite particles, the surface defects of work pieces decrease obviously. So the composite particles as abrasives in slurry have been paid more attention. In order to reduce defect caused by pure α-Al2O3 abrasive, α-alumina-g-polystyrene sulfonic acid (α-Al2O3-g-PSS) composite abrasive was prepared by surface graft polymerization. The composition, structure and morphology of the product were characterized by Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), time-of-flight secondary ion mass spectroscopy(TOF-SIMS), and scanning electron microscopy(SEM), respectively. The results show that polystyrene sulfonic acid grafts onto α-Al2O3, and has well dispersibility. Then, the chemical mechanical polishing performances of the composite abrasive on glass substrate were investigated with a SPEEDFAM-16B-4M CMP machine. Atomic force microscopy(AFM) images indicate that the average roughness of the polished glass substrate surface can be decreased from 0.835 nm for pure α-Al2O3 abrasive to 0.583 nm for prepared α-Al2O3-g-PSS core-shell abrasive. The research provides a new and effect way to improve the surface qualities during CMP.

  3. Effect of Chemicals on Chemical Mechanical Polishing of Glass Substrates

    Institute of Scientific and Technical Information of China (English)

    WANG Liang-Yong; ZHANG Kai-Liang; SONG Zhi-Tang; FENG Song-Lin

    2007-01-01

    @@ We investigate the effect of chemicals on chemical mechanical polishing (CMP) of glass substrates. Ceria slurry in an ultra-low concentration of 0.25wt.% is used and characterized by scanning electron microscopy. Three typical molecules, i.e. acetic acid, citric acid and sodium acrylic polymer, are adopted to investigate the effect on CMP performance in terms of material removal rate (MRR) and surface quality. The addition of sodium acrylic polymer shows the highest MRR as well as the best surface by atomic force microscopy after CMP, vhile the addition of citric acid shows the worst performance. These results reveal a mechanism that a long-chain molecule without any branches rather than small molecules and common molecules with ramose abundant-electron groups is better for the dispersion of the slurry and thus better for the CMP process.

  4. Chemical mechanical polishing of steel substrate using colloidal silica-based slurries

    Science.gov (United States)

    Jiang, Liang; He, Yongyong; Luo, Jianbin

    2015-03-01

    AISI 52100 steel has been widely used in the mechanical industry due to its excellent mechanical properties and high availability. In some cases, an ultra-smooth surface of AISI 52100 steel is needed and is even indispensable for the satisfactory performance of devices. In this paper, chemical mechanical polishing technique was employed to prepare the ultra-smooth surface of AISI 52100 steel. Colloidal silica was used as the abrasive. The effects of pH, complexing agent such as glycine, H2O2 and benzotriazole (BTA) on the polishing performance were studied. It is revealed that, with the increase of pH, the static etching rate (SER) and the material removal rate (MRR) are both gradually reduced, and the post-CMP surface roughness Ra decreases. This is attributed to the fact that compact and passive iron oxides, especially Fe(III) oxides, gradually form on the top surface. At pH 4.00, in the presence of glycine, and with the increase of the H2O2 concentration, the SER is further suppressed, and the surface roughness Ra gradually decreases; the MRR initially dramatically increases due to the fact that, with the addition of small amount of H2O2, the porous iron oxide layer with relatively low mechanical strength can be rapidly formed on the surface. Moreover, glycine intensifies the chemical dissolution by chelating iron ions, especially Fe(II) ions, and thereby the mechanical strength of the oxide layer further weakens. Then, after reaching the peak value, the MRR gradually decreases when the H2O2 concentration further increases since the compactness of the oxide layer gradually increases. With the increase of the BTA concentration, the MRR is gradually suppressed and the surface roughness Ra decreases due to the formation of Fe-BTA passivating film on the top surface. Finally, a two-step polishing process was developed. The polishing results show that, within 20 min, a rough surface of AISI 52100 steel with the Ra value of 188 nm can be polished into an ultra

  5. Material removal model for non-contact chemical mechanical polishing

    Institute of Scientific and Technical Information of China (English)

    ZHANG JianQun; ZHANG ChaoHui

    2008-01-01

    Material removal mechanism under non-contact condition between the pad and the wafer in the chemical mechanical polishing (CMP) process is investigated. Based on the assumption that almost all effective material removals take place due to the active abrasives which cut material through the plowing effects. A novel model is developed to predict the material removal rate (MRR) under non-contact condition between the pad and the wafer in CMP. Validated by the experimental data, the model is proved to be able to predict the change of MRR under non-contact condition. Numerical simulation of the model shows: the relative velocity u between the pad and the wafer and fluid viscosity η are the most important factors which impact MRR under non-contact condition; load changes of wafer also affects the MRR, but the effect is not as obvious as the relative velocity and fluid viscosity;when the radius of abrasive is not less than 50nm, the impact of MRR alone with the changes in the size of the abrasive can be ignored.

  6. Electrochemical and mechanical polishing and shaping method and system

    Science.gov (United States)

    Engelhaupt, Darell E. (Inventor); Gubarev, Mikhail V. (Inventor); Jones, William David (Inventor); Ramsey, Brian D. (Inventor); Benson, Carl M. (Inventor)

    2011-01-01

    A method and system are provided for the shaping and polishing of the surface of a material selected from the group consisting of electrically semi-conductive materials and conductive materials. An electrically non-conductive polishing lap incorporates a conductive electrode such that, when the polishing lap is placed on the material's surface, the electrode is placed in spaced-apart juxtaposition with respect to the material's surface. A liquid electrolyte is disposed between the material's surface and the electrode. The electrolyte has an electrochemical stability constant such that cathodic material deposition on the electrode is not supported when a current flows through the electrode, the electrolyte and the material. As the polishing lap and the material surface experience relative movement, current flows through the electrode based on (i) adherence to Faraday's Law, and (ii) a pre-processing profile of the surface and a desired post-processing profile of the surface.

  7. Investigation of slurry systems in metal and dielectric chemical mechanical polishing

    Science.gov (United States)

    Lu, Zhenyu

    The properties of slurries play a significant role in chemical mechanical polishing (CMP) of metal and dielectric films in semiconductor device manufacturing. This study investigates the effects of the size, shape, and hardness of uniform abrasive particles of simple and composite natures on the polishing of copper, tantalum, and thermal oxide films in the presence of different chemical reagents. It was shown that the total surface area of the solids in the slurry controlled the material removal rate by pure silica for both Cu and Ta, while the surface quality of the polished films was better when using higher silica contents. Ceria particles are the choice abrasives in polishing of oxide surfaces. Since it is difficult to prepare in quantities uniform ceria particles of various shapes, the latter were prepared by using monodispersed cubic and ellipsoidal hematite (Fe2O3) particles and spherical silica, and coating them with nanosized ceria. The polishing data were then obtained using slurries of all these particles and the results were compared with slurries containing only nanosized ceria. At the same pH and the same solid content, the removal rates of these slurries followed the contact area model. Furthermore, slurries containing mixtures of particles performed more efficiently than those of individual particles. Interactions of abrasive particles with surface films to be polished are also very important in CMP. In this study, the packed column technique was employed to investigate the physical and chemical reactions at the particle/film interfaces under conditions that simulate CMP processes. Well-defined dispersions of uniform particles, including spherical silica, calcined alumina, and silica cores coated with nanosized ceria particles were used to evaluate particle adhesion on copper and glass beads. It was shown that pH and the slurry flow rate had significant effects on particle deposition and detachment. The attachment results of silica particles on

  8. Polishing mechanism of light-initiated dental composite: Geometric optics approach.

    Science.gov (United States)

    Chiang, Yu-Chih; Lai, Eddie Hsiang-Hua; Kunzelmann, Karl-Heinz

    2016-12-01

    For light-initiated dental hybrid composites, reinforcing particles are much stiffer than the matrix, which makes the surface rugged after inadequate polish and favors bacterial adhesion and biofilm redevelopment. The aim of the study was to investigate the polishing mechanism via the geometric optics approach. We defined the polishing abilities of six instruments using the obtained gloss values through the geometric optics approach (micro-Tri-gloss with 20°, 60°, and 85° measurement angles). The surface texture was validated using a field emission scanning electron microscope (FE-SEM). Based on the gloss values, we sorted polishing tools into three abrasive levels, and proposed polishing sequences to test the hypothesis that similar abrasive levels would leave equivalent gloss levels on dental composites. The three proposed, tested polishing sequences included: S1, Sof-Lex XT coarse disc, Sof-Lex XT fine disc, and OccluBrush; S2, Sof-Lex XT coarse disc, Prisma Gloss polishing paste, and OccluBrush; and S3, Sof-Lex XT coarse disc, Enhance finishing cups, and OccluBrush. S1 demonstrated significantly higher surface gloss than the other procedures (p geometric optic approach is an efficient and nondestructive method to characterize the polished surface of dental composites. Copyright © 2015. Published by Elsevier B.V.

  9. Study on planarization machining of sapphire wafer with soft-hard mixed abrasive through mechanical chemical polishing

    Science.gov (United States)

    Xu, Yongchao; Lu, Jing; Xu, Xipeng

    2016-12-01

    This study investigated the material removal mechanism of sapphire wafer with soft-hard mixed abrasives through mechanical chemical polishing (MCP). The polishing film, which contains diamond as hard abrasives and high reactivity silica as soft abrasives, is prepared through sol-gel technology. Silica abrasives with regular spherical shape and high reactivity are prepared through hydrolysis-precipitation. Diamond grits with three different particle sizes are used as abrasives. Results show that the rate of material removal of mixed abrasives during MCP is more than 52.6% of that of single hard abrasives and the decrease in surface roughness is more than 21.6% of that of single hard abrasives. These results demonstrate that the ideal planarization of sapphire wafer with high removal rate and good surface quality can be achieved when the effect of mechanical removal of hard abrasives and the chemical corrosion effect of soft abrasives are in dynamic equilibrium. A model that describes the material removal mechanism of sapphire with mixed abrasives during MCP is proposed. The results of thermodynamic calculation and polishing residue analysis are used to demonstrate the rationality of the model.

  10. KDP Aqueous Solution-in-Oil Microemulsion for Ultra-Precision Chemical-Mechanical Polishing of KDP Crystal

    Directory of Open Access Journals (Sweden)

    Hui Dong

    2017-03-01

    Full Text Available A novel functional KH2PO4 (KDP aqueous solution-in-oil (KDP aq/O microemulsion system for KDP crystal ultra-precision chemical-mechanical polishing (CMP was prepared. The system, which consisted of decanol, Triton X-100, and KH2PO4 aqueous solution, was available at room temperature. The functional KDP aq/O microemulsion system was systematically studied and applied as polishing solution to KDP CMP technology. In this study, a controlled deliquescent mechanism was proposed for KDP polishing with the KDP aq/O microemulsion. KDP aqueous solution, the chemical etchant in the polishing process, was caged into the micelles in the microemulsion, leading to a limitation of the reaction between the KDP crystal and KDP aqueous solution only if the microemulsion was deformed under the effect of the external force. Based on the interface reaction dynamics, KDP aqueous solutions with different concentrations (cKDP were applied to replace water in the traditional water-in-oil (W/O microemulsion. The practicability of the controlled deliquescent mechanism was proved by the decreasing material removal rate (MRR with the increasing of the cKDP. As a result, the corrosion pits on the KDP surface were avoided to some degree. Moreover, the roughnesses of KDP with KDP aq/O microemulsion (cKDP was changed from 10 mM to 100 mM as polishing solutions were smaller than that with the W/O microemulsion. The smallest surface root-mean-square roughness of 1.5 nm was obtained at a 30 mmol/L KDP aq solution, because of the most appropriate deliquescent rate and MRR.

  11. Chemical mechanical polishing of transparent conductive layers using spherical cationic polymer microbeads

    Energy Technology Data Exchange (ETDEWEB)

    Nagaoka, Shoji, E-mail: nagaoka@kmt-iri.go.jp [Kumamoto Industrial Research Institute, 3-11-38 Higashimachi, Higashiku, Kumamoto 862-0901 (Japan); Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Chuouku, Kumamoto 860-8555 (Japan); Kumamoto Institute for Photo-Electro Organics (Phoenics), 3-11-38 Higashimachi, Higashiku, Kumamoto 862-0901 (Japan); Ryu, Naoya [Kumamoto Industrial Research Institute, 3-11-38 Higashimachi, Higashiku, Kumamoto 862-0901 (Japan); Yamanouchi, Akio [Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Chuouku, Kumamoto 860-8555 (Japan); Shirosaki, Tomohiro [Kumamoto Industrial Research Institute, 3-11-38 Higashimachi, Higashiku, Kumamoto 862-0901 (Japan); Kumamoto Institute for Photo-Electro Organics (Phoenics), 3-11-38 Higashimachi, Higashiku, Kumamoto 862-0901 (Japan); Horikawa, Maki [Kumamoto Industrial Research Institute, 3-11-38 Higashimachi, Higashiku, Kumamoto 862-0901 (Japan); Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Chuouku, Kumamoto 860-8555 (Japan); Kumamoto Institute for Photo-Electro Organics (Phoenics), 3-11-38 Higashimachi, Higashiku, Kumamoto 862-0901 (Japan); Sakurai, Hideo; Takafuji, Makoto; Ihara, Hirotaka [Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Chuouku, Kumamoto 860-8555 (Japan); Kumamoto Institute for Photo-Electro Organics (Phoenics), 3-11-38 Higashimachi, Higashiku, Kumamoto 862-0901 (Japan)

    2015-02-02

    Spherical cationic polymer microbeads were used to chemically mechanically polish transparent conductive oxide (TCO) layers without the need for inorganic abrasives. Poly(methyl acrylate) (PMA) was used as the polymer matrix. Surface cationization of the spherical PMA microbeads was achieved by aminolysis using 1,2-diaminoethane. The amino group content of the microbeads was controlled using the aminolysis reaction time. The surface roughness of the TCO polished using the cationic polymer microbeads was similar to that of TCO polished with an inorganic abrasive. The microbead-polished TCO layer was slightly thinner than the unpolished TCO layer. The sheet resistance of the TCO layer polished using the microbeads was lower than that polished using the inorganic abrasive. The TCO polishing ability of the microbeads was dependent on their cationic properties and softness. - Highlights: • Indium tin oxide (ITO) layer was planarized using cationic polymer microbeads. • Cationic polymer microbeads planarized, while retaining ITO layer thickness • Cationic polymer microbeads did not degrade the sheet resistance of ITO. • Cationic polymer microbeads could planarize the ITO surface without damaging.

  12. The Effect of Heat Treatment and Mechanical Polishing on Nitinol Stent

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Soo; Lee, Se Chol; Kim, Kyu Suk; Choi, Seong Hoon; Park, Chan Soo [Eulji University, Daejeon (Korea, Republic of); Yoon, Chang Jin; Kang, Sung Gwon [Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Park, Jae Hyung [Seoul National University Hospital, Seoul (Korea, Republic of)

    2009-09-15

    To understand the effect of heat treatment and mechanical polishing of a Nitinol wire on the chemical composition and physical morphology of the wire surface. Stents with a diameter of 1.0 cm, length of 8-10 cm, and composed of a Nitinol wire, were heat-treated at 500 .deg. C for 30 minutes, and mechanically polished with walnut shell granules. The wire surface morphology was studied with both an optical and a scanning electron microscope (SEM). In addition, an elemental analysis was performed by Energy Dispersive X-ray spectroscopy (EDX). Long microcracks along the wire direction and short microcracks across the wire were observed by SEM from the raw Nitinol wire. Upon heat treatment, the color of the wire turned blue, and Na, K, Cl, Si, Al atoms were seen from the EDX of the heat treated wire, which were absent in the original wire. The microcracks disappeared with the mechanical polishing, and the Na, K, Cl, Si, Al atoms all disappeared after the mechanical polishing. Mechanical polishing using walnut shell granules effectively removed the microcracks of a nitinol wire and impurities produced from the heat treatment.

  13. Models of nanoparticles movement, collision, and friction in chemical mechanical polishing (CMP)

    Energy Technology Data Exchange (ETDEWEB)

    Ilie, Filip, E-mail: filip@meca.omtr.pub.ro [Polytechnic University of Bucharest, Department of Machine Elements and Tribology (Romania)

    2012-03-15

    Nanoparticles have been widely used in polishing slurry such as chemical mechanical polishing (CMP) process. The movement of nanoparticles in polishing slurry and the interaction between nanoparticles and solid surface are very important to obtain an atomic smooth surface in CMP process. Polishing slurry contains abrasive nanoparticles (with the size range of about 10-100 nm) and chemical reagents. Abrasive nanoparticles and hydrodynamic pressure are considered to cause the polishing effect. Nanoparticles behavior in the slurry with power-law viscosity shows great effect on the wafer surface in polishing process. CMP is now a standard process of integrated circuit manufacturing at nanoscale. Various models can dynamically predict the evolution of surface topography for any time point during CMP. To research, using a combination of individual nanoscale friction measurements for CMP of SiO{sub 2}, in an analytical model, to sum these effects, and the results scale CMP experiments, can guide the research and validate the model. CMP endpoint measurements, such as those from motor current traces, enable verification of model predictions, relating to friction and wear in CMP and surface topography evolution for different types of CMP processes and patterned chips. In this article, we explore models of the microscopic frictional force based on the surface topography and present both experimental and theoretical studies on the movement of nanoparticles in polishing slurry and collision between nanoparticles, as well as between the particles and solid surfaces in time of process CMP. Experimental results have proved that the nanoparticle size and slurry properties have great effects on the polishing results. The effects of the nanoparticle size and the slurry film thickness are also discussed.

  14. Synthesis and Characterization of SiO2 Nanoparticles and Their Efficacy in Chemical Mechanical Polishing Steel Substrate

    Directory of Open Access Journals (Sweden)

    M. J. Kao

    2014-01-01

    Full Text Available Chemical mechanical polishing (CMP technology is extensively used in the global planarization of highly value-added and large components in the aerospace industry. A nanopowder of SiO2 was prepared by the sol-gel method and was compounded into polishing slurry for the CMP of steel substrate. The size of the SiO2 abrasives was controlled by varying the sol-gel reaction conditions. The polishing efficacy of nano-SiO2 was studied, and the CMP mechanism with nanosized abrasives was further investigated. The proposed methods can produce SiO2 abrasives whose size can be controlled by varying the sol-gel reaction conditions. The size of the SiO2 abrasives was controlled in the range from 58 to 684 nm. The roughness of the steel substrate strongly depends on the size of the abrasive, and the surface roughness decreases as the abrasive size declines. A super-smooth surface with a roughness of 8.4 nm is obtained with nanosized SiO2. Ideal CMP slurry can be used to produce material surfaces with low roughness, excellent global planarization, high selectivity, an excellent finish, and a low-defected rate.

  15. Voltage-induced material removal mechanism of copper for electrochemical-mechanical polishing applications

    Institute of Scientific and Technical Information of China (English)

    Sang-Jun HAN; Yong-Jin SEO

    2009-01-01

    The current-voltage (Ⅰ-Ⅴ) curves, such as linear sweep voltammetry (LSV) and cyclic voltammetry (CV), were employed to evaluate the effect of electrolyte concentration on the electrochemical reaction trend. From the Ⅰ-Ⅴ curve, the electrochemical states of active, passive, transient and trans-passive region could be characterized. And then, the mechanism of the process of voltage-induced material removal in electrochemical mechanical polishing (ECMP) of copper was investigated. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses were used to observe the surface profile. Finally, the oxidation and reduction processes of the Cu surface were monitored by the repetition of anodic and cathodic potential from cyclic voltammetry (CV) method in acid- and alkali-based electrolyte.

  16. Classical molecular dynamics and ab initio simulations of chemical-mechanical polishing of amorphous silica

    Science.gov (United States)

    Chagarov, Evgueni Anatolievich

    Chemical-mechanical polishing (CMP) is a widely accepted process in the semiconductor industry. Despite intense theoretical and experimental research on CMP, there is a serious lack of fundamental understanding of the physical-chemical processes of polishing. The present work is intended to investigate these fundamental processes on an atomistic level. To model CMP on the atomic scale, a model of the amorphous silica is prepared by applying Design of Experiments (DOE) techniques to systematically investigate molecular dynamics preparation. These simulations yield high-quality models of amorphous silica, which are in excellent agreement with experimental results and are defect-free. Molecular dynamics simulations are performed to investigate the mechanical deformation during CMP of silica for different geometries and relative velocities. The simulations clarify asperity shape evolution during the process of shear and reveal temperature distributions as a function of time. It is found that the ratio of radii of a particle and asperity strongly affects the amount of the material removed whereas the relative velocity has a weaker affect on it. During shear, a significant local temperature increase occurs. This temperature increase lasts for a short time (picoseconds), but it can have a major impact on the amount of material removed. It is found that there could be significant deposition of the material from the particle to the slab, which can fill surface trenches and thereby make the surface smoother. An analytic model is developed for describing the amount of material removed as a function of asperity and particle radii and relative velocity. Density-functional calculations of different surfaces of two silica polymorphs, alpha-quartz and beta-cristobalite, are performed. The surface energies are calculated as a function of oxygen partial pressure for several different surface reconstructions and terminations. The case of hydrogen passivation is investigated to

  17. Investigation of the surface generation mechanism of mechanical polishing engineering ceramics using discrete element method

    Science.gov (United States)

    Han, Xuesong

    2014-09-01

    Machining technology about ceramics has been developed very fast over recent years due to the growing industrial demand of higher machining accuracy and better surface quality of ceramic elements, while the nature of hard and brittle ceramics makes it difficult to acquire damage-free and ultra-smooth surface. Ceramic bulk can be treated as an assemblage of discrete particles bonded together randomly as the micro-structure of ceramics consists of crystal particles and pores, and the inter-granular fracture of the ceramics can be naturally represented by the separation of particles due to breakage of bonds. Discrete element method (DEM) provides a promising approach for constructing an effective model to describe the tool-workpiece interaction and can serve as a predicting simulation tool in analyzing the complicated surface generation mechanism and is employed in this research to simulate the mechanical polishing process of ceramics and surface integrity. In this work, a densely packed particle assembly system of the polycrystalline Si3N4 has been generated using bonded-particle model to represent the ceramic workpiece numerically. The simulation results justify that the common critical depth of cut cannot be used as the effective parameters for evaluating brittle to ductile transformation in ceramic polishing process. Therefore, a generalized criterion of defining the range of ductile regime machining has been developed based on the numerical results. Furthermore, different distribution of pressure chain is observed with different depth of cut which ought to have intense relationship with special structure of ceramics. This study also justified the advantage of DEM model in its capability of revealing the mechanical behaviors of ceramics at micro-scale.

  18. Damascene Array Structure of Phase Change Memory Fabricated with Chemical Mechanical Polishing Method

    Institute of Scientific and Technical Information of China (English)

    LIU Qi-Bin; SONG Zhi-Tang; ZHANG Kai-Liang; WANG Liang-Yong; FENG Song-Lin; CHEN Bomy

    2006-01-01

    @@ A damascene structure of phase change memory (PCM) is fabricated successfully with the chemical mechanical polishing (CMP) method, and the CMP of Ge2Sb2Te5 (GST) and Ti films is investigated. The polished surface of wafer is analysed by scanning electron microscopy (SEM) and an energy dispersive spectrometer (EDS). The measurements show that the damascene device structure of phase change memory is achieved by the CMP process.After the top electrode is deposited, dc sweeping test on PCM reveals that the phase change can be observed.The threshold current of array cells varies between 0.90mA and 1.15mA.

  19. Material removal mechanism of copper chemical mechanical polishing in a periodate-based slurry

    Science.gov (United States)

    Cheng, Jie; Wang, Tongqing; He, Yongyong; Lu, Xinchun

    2015-05-01

    The material removal mechanism of copper in a periodate-based slurry during barrier layer chemical mechanical polishing (CMP) has not been intensively investigated. This paper presents a study of the copper surface film chemistry and mechanics in a periodate-based slurry. On this basis, the controlling factor of the copper CMP material removal mechanism is proposed. The results show that the chemical and electrochemical reaction products on the copper surface are complex and vary considerably as a function of the solution pH. Under acidic conditions (pH 4) the copper surface underwent strong chemical dissolution while the corrosion was mild and uniform under alkaline conditions (pH 11). The corrosion effect was the lowest in near neutral solutions because the surface was covered with non-uniform Cu(IO3)2·H2O/Cu-periodate/copper oxides films, which had better passivation effect. The surface film thickness and mechanical removal properties were studied by AES and AFM nano-scratch tests. Based on the combined surface film analysis and CMP experiment results, it can be concluded that the controlling factor during copper CMP in a periodate-based slurry is the chemical-enhanced mechanical removal of the surface films. The periodate-based slurry should be modified by the addition of corrosion inhibitors and complexing agents to achieve a good copper surface quality with moderate chemical dissolution.

  20. Combined Ultrasonic Elliptical Vibration and Chemical Mechanical Polishing of Monocrystalline Silicon

    Directory of Open Access Journals (Sweden)

    Liu Defu

    2016-01-01

    Full Text Available An ultrasonic elliptical vibration assisted chemical mechanical polishing(UEV-CMP is employed to achieve high material removal rate and high surface quality in the finishing of hard and brittle materials such as monocrystalline silicon, which combines the functions of conventional CMP and ultrasonic machining. In theultrasonic elliptical vibration aided chemical mechanical polishingexperimental setup developed by ourselves, the workpiece attached at the end of horn can vibrate simultaneously in both horizontal and vertical directions. Polishing experiments are carried out involving monocrystalline silicon to confirm the performance of the proposed UEV-CMP. The experimental results reveal that the ultrasonic elliptical vibration can increase significantly the material removal rate and reduce dramatically the surface roughness of monocrystalline silicon. It is found that the removal rate of monocrystalline silicon polished by UEV-CMP is increased by approximately 110% relative to that of conventional CMP because a passive layer on the monocrystalline silicon surface, formed by the chemical action of the polishing slurry, will be removed not only by the mechanical action of CMP but also by ultrasonic vibration action. It indicates that the high efficiency and high quality CMP of monocrystalline silicon can be performed with the proposed UEV-CMP technique.

  1. Surface characteristics of ruthenium in periodate-based slurry during chemical mechanical polishing

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Jie; Wang, Tongqing; Jiang, Liang; Lu, Xinchun, E-mail: xclu@tsinghua.edu.cn

    2015-10-01

    Highlights: • The Ru surface chemical and mechanical property varies with KIO{sub 4} slurry pH. • In alkaline slurry, the corrosion proceeds uniformly like a direct dissolution. • In neutral and acidic slurries, Ru exhibits passivation behavior. • MRR is highest in neutral slurry due to inhomogeneous RuO{sub 2}·2H{sub 2}O/RuO{sub 3} passivation. • Weak alkaline slurry is preferred to get good MRR and avoid toxic RuO{sub 4} formation. - Abstract: When the feature size of integrated circuit continues to shrink below 14 nm, ruthenium (Ru) has become one of the most promising candidates for the application of novel barrier layer. To reveal the material removal mechanism of Ru during chemical mechanical polishing (CMP), surface characteristics of Ru in KIO{sub 4}-based slurry were investigated. The corrosion behavior of ruthenium was measured by the surface chemistry and morphology analysis. Then the mechanical properties of the passivated/corroded surface were evaluated by AES and tribocorrosion experiments. CMP experiments were carried out to make clear the effects of surface property during polishing. It was found that the Ru surface chemistry and mechanical properties vary obviously as a function of slurry pH. In neutral slurries, the Ru surface is covered with RuO{sub 2}·2H{sub 2}O/RuO{sub 3} inhomogeneous passivation films, with the highest material removal rate obtained during the CMP process. It could be concluded that the material removal mechanism largely depends on the slurry pH values. In near neutral slurries, Ru is passivated with thick and heterogeneous oxides film, which proves the easiest to be mechanically removed during polishing. The weak alkaline slurry is preferred in order to achieve desirable polishing rate as well as avoid the formation of toxic RuO{sub 4}.

  2. Application of Silicon Selective Epitaxial Growth and Chemo-Mechanical Polishing to Bipolar and Soi Mosfet Devices.

    Science.gov (United States)

    Nguyen, Cuong Tan

    1994-01-01

    Polished Epitaxy, or the combination of silicon Selective Epitaxial Growth and Chemo-Mechanical Polishing, provides new flexibility in process and device design, including optimized isolation, planar active-area definition, low-capacitance contacts, and SOI thin films. In this work, Polished Epitaxy has been developed with particular effort on overcoming junction leakage problems widely reported in devices fabricated in similar processes. It was found that in addition to careful surface preparation and defect control in the selective epitaxy process, issues such as sidewall orientation, junction passivation, crystal annealing, and surface damage removal were equally important and needed to be addressed. Coupled with the proper processing steps, Polished Epitaxy was able to deliver material of comparable quality to bulk silicon, suitable for device applications. By growing epitaxy laterally over an oxide step followed by polishing, a pedestal structure was created in which a thin film of single-crystal silicon was formed over oxide. Serving as the extrinsic base contact to a T-Pedestal bipolar transistor device, this pedestal helped minimize the parasitic extrinsic-base-collector overlap capacitance. The cut-off frequency (f_ {T}) in a device with a 1.0-mu m wide emitter stripe was found to improve from 17GHz to 22GHz when the contact overlap was reduced from a more conventional, larger size of 1.0 mu m to 0.2 mum. It is expected that the high-frequency performance of this structure can still be improved further in an optimized process with reduced emitter and collector resistances. The same pedestal structure was applied to a Pedestal -SOI (Silicon-On-Insulator) MOSFET device concept. At one extreme, a conventional bulk MOSFET structure is obtained when the pedestal is not utilized; quasi-SOI occurs when the drain and part of the channel overlap with the pedestal over buried oxide; at the other extreme, complete-SOI behavior results when source, channel, and drain

  3. Role of crystal orientation on chemical mechanical polishing of single crystal copper

    Science.gov (United States)

    Zhu, Aibin; He, Dayong; Luo, Wencheng; Liu, Yangyang

    2016-11-01

    The material removal mechanism of single crystal copper in chemical mechanical polishing (CMP) has not been intensively investigated. And the role of crystal orientation in CMP of single crystal cooper is not quite clear yet. Quasi-continuum method was adopted in this paper to simulate the process of nano-particles grinding on single crystal copper in CMP process. Three different crystal orientations, i.e. x[100]y[001], x[001]y[110] and x[-211]y[111], were chosen for analysis. The atom displacement diagrams, stress distribution diagrams and load-displacement curves were obtained. After analyzing the deformation mechanism, residual stress of the work piece material and cutting force, results showed that, the crystal orientation of work piece has great influence on the deformation characteristics and surface quality of work piece during polishing. In the A(001)[100] orientation, the residual stress distribution after polishing is deeper, and the stress is larger than that in the B(110)[001] and C(111)[-211] orientations. And the average tangential cutting force in the A(001)[100] orientation is much larger than those in the other two crystal orientation. This research is helpful to revealing the material removal mechanism of CMP process.

  4. Preparation of composite abrasives by electrostatic self-assembly method and its polishing properties in Cu CMP

    Institute of Scientific and Technical Information of China (English)

    Huang Yishen; Xu Xuefeng; Yao Chunyan; Hu Jiande; Peng Wei

    2014-01-01

    The adsorption characteristics of cationic polyelectrolyte poly dimethyl diallyl ammonium chloride (PDADMAC) and anionic polyelectrolyte poly (sodium-p-styrenesulfonate) (PSS) on benzoguanamine formal-dehyde (BGF) particles are investigated. The charging characteristics of BGF particles are changed and con-trolled using electrostatic self-assembly method. A variety of PEi-BGF/SiO2 composite abrasives are obtained. The as-prepared samples are analyzed by zeta potential analysis,transmission electron microscope (TEM) and thermogravimetric (TG) analysis. The composite abrasive slurries are prepared for copper polishing. The poli-shing results indicate that it is SiO2 abrasives,not only coated SiO2 abrasive on polymer particles but also free SiO2 abrasive in slurry ,that offer the polishing action. The material removal rates of copper polishing are 264 nm/min,348 nm/min and 476 nm/min using single SiO2 abrasive slurry,PE0-BGF/SiO2 mixed abrasive slur-ry and PE3-BGF/SiO2 composite abrasive slurry,respectively. The surface roughness Ra of copper wafer (with 5μm× 5μm district) is decreased from 0.166μm to 3.7 nm,2.6 nm and 1.5 nm,and the surface peak-valley values Rpv are less than 20 nm,14 nm and 10 nm using these kinds of slurries,respectively.

  5. Mechanical polishing as an improved surface treatment for platinum screen-printed electrodes

    Directory of Open Access Journals (Sweden)

    Junqiao Lee

    2016-07-01

    Full Text Available The viability of mechanical polishing as a surface pre-treatment method for commercially available platinum screen-printed electrodes (SPEs was investigated and compared to a range of other pre-treatment methods (UV-Ozone treatment, soaking in N,N-dimethylformamide, soaking and anodizing in aqueous NaOH solution, and ultrasonication in tetrahydrofuran. Conventional electrochemical activation of platinum SPEs in 0.5 M H2SO4 solution was ineffective for the removal of contaminants found to be passivating the screen-printed surfaces. However, mechanical polishing showed a significant improvement in hydrogen adsorption and in electrochemically active surface areas (probed by two different redox couples due to the effective removal of surface contaminants. Results are also presented that suggest that SPEs are highly susceptible to degradation by strong acidic or caustic solutions, and could potentially lead to instability in long-term applications due to continual etching of the binding materials. The ability of SPEs to be polished effectively extends the reusability of these traditionally “single-use” devices.

  6. Inducing Changes in Surface Topography of Copper Thin Films: Implications for Chemical Mechanical Polishing

    Science.gov (United States)

    Smith, C. L.; Mitchell, E. J. R.; Koeck, D. C.; Galloway, H. C.

    2000-10-01

    We have investigated the effects of pH and corrosion inhibitors on the surface of Cu films when exposed and polished in H_2O2 based slurries. Acetic Acid was used to buffer H_2O2 into the acidic range necessary to keep the corrosion inhibitor, benzotriazole (BTA) in solution. Surface characteristics were examined using atomic force microscopy and profilometry. Some conditions cause dramatic changes in the surface topography of the Cu films. The original small "grains" that give the film a uniform roughness, disappear and leave large crystalline appearing structures with terrace widths of up to 600 Åand heights of 200-1000 ÅWe believe these changes have strong implications for Chemical Mechanical Polishing processes used to manufacture integrated circuits and will discuss how these changes in surface topography may be occurring.

  7. Evaluation of environmental impacts during chemical mechanical polishing (CMP) for sustainable manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Seop; Park, Sun Joon; Jeong, Hae Do [Pusan National University, Busan (Korea, Republic of)

    2013-02-15

    Reducing energy consumption has become a critical issue in manufacturing. The semiconductor industry in particular is confronted with environmental regulations on pollution associated with electric energy, chemical, and ultrapure water (UPW) consumptions. This paper presents the results of an evaluation of the environmental impacts during chemical mechanical polishing (CMP), a key process for planarization of dielectrics and metal films in ultra-large-scale integrated circuits. The steps in the CMP process are idling, conditioning, wetting, wafer loading/unloading, head dropping, polishing, and rinsing. The electric energy, CMP slurry, and UPW consumptions associated with the process and their impacts on global warming are evaluated from an environmental standpoint. The estimates of electric energy, slurry, and UPW consumptions as well as the associated greenhouse gas emissions presented in this paper will provide a technical aid for reducing the environmental burden associated with electricity consumption during the CMP process.

  8. A study of the preparation of epitaxy-ready polished surfaces of (100) Gallium Antimonide substrates demonstrating ultra-low surface defects for MBE growth

    Science.gov (United States)

    Martinez, Rebecca; Tybjerg, Marius; Flint, Patrick; Fastenau, Joel; Lubyshev, Dmitri; Liu, Amy W. K.; Furlong, Mark J.

    2016-05-01

    Gallium Antimonide (GaSb) is an important Group III-V compound semiconductor which is suitable for use in the manufacture of a wide variety of optoelectronic devices such as infra-red (IR) focal plane detectors. A significant issue for the commercialisation of these products is the production of epitaxy ready GaSb, which remains a challenge for the substrate manufacturer, as the stringent demands of the MBE process, requires a high quality starting wafer. In this work large diameter GaSb crystals were grown by the Czochralski (Cz) method and wafers prepared for chemo-mechanical polishing (CMP). Innovative epi-ready treatments and novel post polish cleaning methodologies were applied. The effect of these modified finishing chemistries on substrate surface quality and the performance of epitaxially grown MBE GaSb IR detector structures were investigated. Improvements in the lowering of surface defectivity, maintaining of the surface roughness and optimisation of all flatness parameters is confirmed both pre and post MBE growth. In this paper we also discuss the influence of bulk GaSb quality on substrate surface performance through the characterisation of epitaxial structures grown on near zero etch pit density (EPD) crystals. In summary progression and development of current substrate polishing techniques has been demonstrated to deliver a consistent improved surface on GaSb wafers with a readily desorbed oxide for epitaxial growth.

  9. Effects of catalyst concentration and ultraviolet intensity on chemical mechanical polishing of GaN

    Science.gov (United States)

    Wang, Jie; Wang, Tongqing; Pan, Guoshun; Lu, Xinchun

    2016-08-01

    Effects of catalyst concentration and ultraviolet intensity on chemical mechanical polishing (CMP) of GaN were deeply investigated in this paper. Working as an ideal homogeneous substrate material in LED industry, GaN ought to be equipped with a smooth and flat surface. Taking the strong chemical stability of GaN into account, photocatalytic oxidation technology was adopted in GaN CMP process to realize efficient removal. It was found that, because of the improved reaction rate of photocatalytic oxidation, GaN material removal rate (MRR) increases by a certain extent with catalyst concentration increasing. Cross single line analysis on the surface after polishing by Phase Shift MicroXAM-3D was carried out to prove the better removal effect with higher catalyst concentration. Ultraviolet intensity field in H2O2-SiO2-based polishing system was established and simulated, revealing the variation trend of ultraviolet intensity around the outlet of the slurry. It could be concluded that, owing to the higher planarization efficiency and lower energy damage, the UV lamp of 125 W is the most appropriate lamp in this system. Based on the analysis, defects removal model of this work was proposed to describe the effects of higher catalyst concentration and higher power of UV lamp.

  10. Role of crystal orientation on chemical mechanical polishing of single crystal copper

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Aibin, E-mail: abzhu@mail.xjtu.edu.cn; He, Dayong; Luo, Wencheng; Liu, Yangyang

    2016-11-15

    Highlights: • The role of crystal orientation in cooper CMP by quasi-continuum was studied. • The atom displacement diagrams were obtained and analyzed. • The stress distribution diagrams and load-displacement curves were analyzed. • This research is helpful to revealing the material removal mechanism of CMP. - Abstract: The material removal mechanism of single crystal copper in chemical mechanical polishing (CMP) has not been intensively investigated. And the role of crystal orientation in CMP of single crystal cooper is not quite clear yet. Quasi-continuum method was adopted in this paper to simulate the process of nano-particles grinding on single crystal copper in CMP process. Three different crystal orientations, i.e. x[100]y[001], x[001]y[110] and x[–211]y[111], were chosen for analysis. The atom displacement diagrams, stress distribution diagrams and load-displacement curves were obtained. After analyzing the deformation mechanism, residual stress of the work piece material and cutting force, results showed that, the crystal orientation of work piece has great influence on the deformation characteristics and surface quality of work piece during polishing. In the A(001)[100] orientation, the residual stress distribution after polishing is deeper, and the stress is larger than that in the B(110)[001] and C(111)[–211] orientations. And the average tangential cutting force in the A(001)[100] orientation is much larger than those in the other two crystal orientation. This research is helpful to revealing the material removal mechanism of CMP process.

  11. Effect of Nano-sized CeO2 Abrasives on Chemical Mechanical Polishing of Silicon Wafer

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bao-sen; CHEN Yang

    2006-01-01

    The conception of the soft layer during chemical mechanical polishing(CMP) was proposed for the first time. The soft layer was a reaction layer formed on the silicon surface; it was softer than the silicon substrate and its thickness was about several nanometers. The existence of the soft layer could increase the material volume removed by one particle and increase the material removal rate during CMP. At the same time, the soft layer could decrease the cutting depth of the abrasive particle so as to realize ductile grinding, and it is useful to decrease the roughness of the polished surface and to improve the polishing quality.

  12. Fe-N{sub x}/C assisted chemical–mechanical polishing for improving the removal rate of sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Li, E-mail: xl0522@126.com [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Zou, Chunli; Shi, Xiaolei [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Pan, Guoshun, E-mail: pangs@tsinghua.edu.cn [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Luo, Guihai; Zhou, Yan [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

    2015-07-15

    Highlights: • A novel non-noble metal catalyst (Fe-N{sub x}/C) was prepared. • Fe-N{sub x}/C shows remarkable catalytic activity for improving the removal rate of sapphire in alkaline solution. • The optimum CMP removal by Fe-N{sub x}/C yielded a superior surface finish of 0.078 nm the average roughness. • Fe{sub 2}O{sub 3}, Fe{sub 3}O{sub 4}, pyridinic N as well as pyrrolic N group possibly serving as the catalytic sites. • A soft hydration layer (boehmite, AlO(OH)) was generated on the surface of sapphire during CMP process. - Abstract: In this paper, a novel non-noble metal catalyst (Fe-N{sub x}/C) is used to improve the removal mass of sapphire as well as obtain atomically smooth sapphire wafer surfaces. The results indicate that Fe-N{sub x}/C shows good catalytic activity towards sapphire removal rate. And the material removal rates (MRRs) are found to vary with the catalyst content in the polishing fluid. Especially that when the polishing slurry mixes with 16 ppm Fe-N{sub x}/C shows the maximum MRR and its removal mass of sapphire is 38.43 nm/min, more than 15.44% larger than traditional CMP using the colloidal silicon dioxide (SiO{sub 2}) without Fe-N{sub x}/C. Catalyst-assisted chemical–mechanical polishing of sapphire is studied with X-ray photoelectron spectroscopy (XPS). It is found that the formation of a soft hydration layer (boehmite, γ-AlOOH or γ-AlO(OH)) on sapphire surface facilitates the material removal and achieving fine surface finish on basal plane. Abrasives (colloid silica together with magnetite, ingredient of Fe-N{sub x}/C) with a hardness between boehmite and sapphire polish the c-plane of sapphire with good surface finish and efficient removal. Fe{sub 2}O{sub 3}, Fe{sub 3}O{sub 4}, pyridinic N as well as pyrrolic N group would be the catalytical active sites and accelerate this process. Surface quality is characterized with atomic force microscopy (AFM). The optimum CMP removal by Fe-N{sub x}/C also yields a superior

  13. Study of Cu-Inhibitor State for Post-Chemical Mechanical Polishing Cleaning

    Science.gov (United States)

    Harada, Ken; Ito, Atsushi; Kawase, Yasuhiro; Suzuki, Toshiyuki; Hara, Makoto; Sakae, Rina; Kimura, Chiharu; Aoki, Hidemitsu

    2011-05-01

    In order to reduce corrosion on the Cu surface in post-chemical mechanical polishing (CMP) cleaning, controlling the state of inhibitor layers is indispensable. In this study, to investigate the behavior of inhibitor layers in the cleaning process, Cu-benzotriazole (BTA) layers on CuOX were analyzed by electrochemical measurements and surface analysis. Electrochemical measurements revealed that Cu(I)-BTA can prevent corrosion more efficiently than Cu(II)-BTA, and surface analysis revealed that the Cu(I)-BTA layer is thin, whereas the Cu(II)-BTA layer is bulky. The Cu(I)-BTA layer is effective in preventing corrosion of the Cu surface.

  14. The Polishing of Cutting-Edge Polymer-on-Glass for Pigtailing Preparation

    Directory of Open Access Journals (Sweden)

    Mohammad S.A. Rahman

    2009-01-01

    Full Text Available Problem statement: The high quality of cutting-edge surface is important in optical waveguide's efficiency. The perfect polishing of end surface is significant to deliver the best quality of light waves and minimize the device losses such as insertion loss and return loss. Hence, this research is concern on the parameters in polishing SU-8 polymer to increase the efficiency of waveguide. The main research is to study on how polishing parameter affect the cut length of the end surface of SU-8 polymer on silicon and determining the best parameters for polishing SU-8 polymer. Approach: Seven sets of rotation velocities were chosen which were 50, 100, 150, 200, 250, 300 and 350 rpm for the first part. The graph of cut length versus velocity at different sand paper size was plotted based on the data obtained from this experiment. Equation for each graph was acquired to determine relationship between these two parameters. For the second part, four samples were used. Each sample was polished with same rotation time and sandpaper size prescribed but with different rotation speed. Rotation speed is selected between 200 to 350 rpm with rotation time of 15 min using sandpaper with size of 0.3µm. Results: We found that the cut percentage of each rotation velocity are as follows: 50 rpm: ≤0.5%, 100 rpm: 0.6-1.0%, 150 rpm: 3.8-4.8%, 200 rpm: 7.7-10.6%, 250 rpm: 15.7-18.3%, 300 rpm: 25.6-27.4%, 350 rpm: 40.0-43.7%. The rotation speed suitable for polishing SU-8 polymer is below 200 rpm and the rotation speed over the point (ex. 300 rpm will cause cracking to the polymer although the silicon based layer look smooth. Conclusion: In this experiment it was found that the cut length increases as the rotation rate and the size of sand paper increased. It can also be concluded that polishing the sample at the speed of 200 rpm is the best polishing method for polymer SU-8 waveguide, at 15 min rotation time with the used of 0.3µm Aluminium oxide sandpaper size

  15. The intrinsically high pitting corrosion resistance of mechanically polished nitinol in simulated physiological solutions.

    Science.gov (United States)

    Bai, Zhijun; Rotermund, Harm H

    2011-10-01

    Nitinol wires have been widely used in many biomedical applications, such as cardiovascular stent due to their superelasticity and shape memory effect. However, their corrosion properties and the related biocompatibility are not well understood, and the reported results are controversial. In this study, we evaluate the pitting corrosion property of nitinol, titanium, nickel, and 316L stainless steel (316LSS) wires with different surface roughnesses in a saline solution at 37 °C. The cyclic potentiodynamic polarization results show that mechanically polished nitinol and Ti wires are highly resistant to pitting corrosion, while Ni and 316LSS wires are susceptible to pitting corrosion. Electrochemical impedance spectroscopy is used to study the interface of oxide film/solution and all mechanically polished nitinol wires are covered by 2-3 nm thick films formed under open circuit potential. Furthermore, the electronic structures and semiconducting properties of passive films on nitinol, Ti and Ni wires are studied by Mott-Schottky analysis. Passive films formed on nitinol and Ti exhibit n-type semiconducting characteristics, whereas films on Ni show p-type semiconducting characteristics. Scanning Kelvin Microscopy is used to measure the surface potential difference between common inclusions from the nitinol matrix and the results indicate that the inclusions are more electrochemically noble than the nitinol matrix. Band energy theory is used to model the electrochemical interface between the passive films of nitinol and the solution under different applied potential conditions. A mechanism for the strong pitting corrosion resistance of nitinol in saline solution is proposed.

  16. Evaluation of subsurface damage in GaN substrate induced by mechanical polishing with diamond abrasives

    Energy Technology Data Exchange (ETDEWEB)

    Aida, Hideo, E-mail: h-aida@namiki.net [NJC Institute of Technology, Namiki Precision Jewel Co., Ltd., 3-8-22 Shinden, Adachi, Tokyo 123-8511 (Japan); KASTEC, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan); Takeda, Hidetoshi; Kim, Seong-Woo; Aota, Natsuko; Koyama, Koji [NJC Institute of Technology, Namiki Precision Jewel Co., Ltd., 3-8-22 Shinden, Adachi, Tokyo 123-8511 (Japan); Yamazaki, Tsutomu; Doi, Toshiro [KASTEC, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan)

    2014-02-15

    The relationship between the depth of the subsurface damage (SSD) and the size of the diamond abrasive used for mechanical polishing (MP) of GaN substrates was investigated in detail. GaN is categorized as a hard, brittle material, and material removal in MP proceeds principally to the fracture of GaN crystals. Atomic force microscopy and cathodoluminescence imaging revealed that the mechanical processing generated surface scratches and SSD. The SSD depth reduced as the diamond abrasive size reduced. A comparison of the relationship between the SSD depth and the diamond abrasive size used in the MP of GaN with the same relationship for typical brittle materials such as glass substrates suggests that the MP of GaN substrates proceeds via the same mechanism as glass.

  17. Core/shell composites with polystyrene cores and meso-silica shells as abrasives for improved chemical mechanical polishing behavior

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yang, E-mail: cy.jpu@126.com; Qin, Jiawei; Wang, Yayun; Li, Zefeng [Changzhou University, School of Material Science and Engineering (China)

    2015-09-15

    The core/shell-structured organic/inorganic composite abrasive has an important potential application in damage-free chemical mechanical polishing (CMP) due to its non-rigid mechanical property. In this work, the PS/{sub M}SiO{sub 2} composites, containing polystyrene (PS) sphere (211 ± 4 nm) cores and mesoporous silica shells (31 ± 3 nm in thickness) were synthesized through directed surface sol–gel process of tetraethylorthosilicate on the polymer cores in the presence of the cetyltrimethylammonium bromide surfactant. For comparison, the conventional core/shell PS/{sub N}SiO{sub 2} composites with non-porous silica shells were also prepared via a modified Stöber procedure that involved the hydrolysis of TEOS under acidic condition. The physical properties of the samples were examined by small-angle X-ray diffraction, fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, field emission scanning electron microscopy, and nitrogen adsorption–desorption. As novel abrasives, the core/shell-structured PS/{sub M}SiO{sub 2} composites were introduced into the CMP process for silicon oxide films. The oxide-CMP performance among conventional solid silica particles, PS/{sub N}SiO{sub 2} composites, and novel PS/{sub M}SiO{sub 2} composites was explored by atomic force microscopy. Polishing results indicated that the substrate revealed a comparable root-mean-square surface roughness (0.25 ± 0.03 and 0.22 ± 0.02 nm, respectively) after CMP with PS/{sub N}SiO{sub 2} and PS/{sub M}SiO{sub 2} abrasives under the same polishing conditions. However, the material removal rate of the PS/{sub M}SiO{sub 2} composites (123 ± 15 nm/min) was about three times larger than that of the PS/{sub N}SiO{sub 2} composites (47 ± 13 nm/min). The reduced surface roughness and improved removal rate might be due to the optimization of the physical and/or chemical environments in the local contacting region between abrasives

  18. The impact of polishing on germanium-on-insulator substrates

    Institute of Scientific and Technical Information of China (English)

    Lin Wang; Ruan Yujiao; Chen Songyan; Li Cheng; Lai Hongkai; Huang Wei

    2013-01-01

    We prepared germanium-on-insulator (GOI) substrates by using Smart-CutTM and wafer bonding technology.The fabricated GOI is appropriate for polishing due to a strong bonding strength (2.4 MPa) and a sufficient bonding quality.We investigated mechanical polishing and chemical-mechanical polishing (CMP) systematically,and an appropriate polishing method-mechanical polishing combined with CMP-is obtained.As shown by AFM measurement,the RMS of GOI after polishing decreased to 0.543 nm.And the Ge peak profile of the XRD curve became symmetric,and the FWHM is about 121.7 arcsec,demonstrating a good crystal quality.

  19. Evaluation of Cu Ion Concentration Effects on Cu Etching Rate in Chemical-Mechanical Polishing Slurry

    Science.gov (United States)

    Nishizawa, Hideaki; Sugiura, Osamu; Matsumura, Yoshiyuki; Kinoshita, Masaharu

    2007-04-01

    The effects of Cu ion concentration of the different solutions on Cu etching rate were investigated. From the dipping experiment of Cu substrates in different solutions of malic acid, hydrogen peroxide (H2O2), benzotriazole (BTA), and Cu ions, it was revealed that Cu etching rate is increased if the concentration of Cu(II) ions added in the solution is high. This is considered to be caused by the effect of Cu(II) ions on H2O2 molecules. In the solution of pH 7, the Cu etching rate increased markedly between 1.7× 10-4 and 3.4× 10-4 M Cu(II) ion concentrations. The maximum increase in the etching rate was from 990 to 2200 nm/min at a H2O2 concentration of 2 wt %. In the solution of pH 3, a marked change in the etching rate was not observed. Our results show that the concentration of Cu ions on the polishing pad in chemical-mechanical polishing (CMP) process is very important.

  20. Reactive Ion Etching as Cleaning Method Post Chemical Mechanical Polishing for Phase Change Memory Device

    Institute of Scientific and Technical Information of China (English)

    ZHONG Min; SONG Zhi-Tang; LIU Bo; FENG Song-Lin; CHEN Bomy

    2008-01-01

    In order to improve nano-scale phase change memory performance,a super-clean interface should be obtained after chemical mechanical polishing (CMP) of Ge2Sb2Te5 phase change films.We use reactive ion etching (RIE) as the cleaning method.The cleaning effect is analysed by scanning electron microscopy and an energy dispersive spectrometer.The results show that particle residue on the surface has been removed.Meanwhile,Ge2 Sb2 Te5 material stoichiometric content ratios are unchanged.After the top electrode is deposited,currentvoltage characteristics test demonstrates that the set threshold voltage is reduced from 13 V to 2.7V and the threshold current from 0.1 mA to 0.025 mA.Furthermore,we analyse the RIE cleaning principle and compare it with the ultrasonic method.

  1. Slurry Chemical Corrosion and Galvanic Corrosion during Copper Chemical Mechanical Polishing

    Science.gov (United States)

    Kondo, Seiichi; Sakuma, Noriyuki; Homma, Yoshio; Ohashi, Naofumi

    2000-11-01

    Copper (Cu) corrosion during chemical mechanical polishing (CMP) was controlled in order to improve the Cu damascene interconnect process. Slurry chemical corrosion was found to be enhanced when the slurry was diluted by deionized (DI) water during rinsing just after CMP@. Since the corrosion inhibitor, benzotriazole (BTA), reduces the Cu removal rate, adding it to the rinse solution prevents chemical corrosion more effectively than adding it to the slurry. On the other hand, galvanic corrosion occurs at the interface between Cu and the barrier metal, and it can be prevented by selecting appropriate barrier metals. Because the difference between the electrochemical potentials of Cu and the barrier metal is small in the slurry, refractory metals such as Ta, TaN, and TiN were found to be appropriate barrier metals. On the other hand, W, WN, and Ti have large potential differences, so galvanic corrosion was clearly observed when Cu/W damascene interconnects were fabricated.

  2. Nanotopography Impact in Shallow Trench Isolation Chemical Mechanical Polishing-Dependence on Slurry Characteristics

    Institute of Scientific and Technical Information of China (English)

    Jea-Gun Park; Takeo Katoh; Ungyu Paik

    2004-01-01

    The nanotopography of the surface of silicon wafers has become an important issue in ULSI device manufacturing since it affects the post-chemical mechanical polishing (post-CMP) uniformity of the thickness deviation of dielectric films. In this study, the nanotopography impact was investigated in terms of its dependence on the characteristics of ceriabased slurries, such as the abrasive size, the grain size of the polycrystalline abrasive and the surfactant added to the slurry. It was found that the magnitude of the post-CMP oxide thickness deviation due to nanotopography increased with the surfactant concentration in the case of smaller abrasives but was almost independent of the concentration in the case of larger abrasives. The grain size of the polycrystalline abrasive did not affect the nanotopography impact.

  3. Effect of conditioner load on the polishing pad surface during chemical mechanical planarization process

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Cheol Min; Qin, Hong Yi; Hong, Seok Jun; Jeon, Sang Hyuk; Kulkarni, Atul; Kim, Tae Sun [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-12-15

    During the Chemical mechanical planarization (CMP), the pad conditioning process can affect the pad surface characteristics. Among many CMP process parameters, the improper applied load on the conditioner arm may have adverse effects on the polyurethane pad. In this work, we evaluated the pad surface properties under the various conditioner arm applied during pad conditioning process. The conditioning pads were evaluated for surface topography, surface roughness parameters such as Rt and Rvk and Material removal rate (MRR) and within-wafer non-uniformity after wafer polishing. We observed that, the pad asperities were collapsed in the direction of conditioner rotation and blocks the pad pores applied conditioner load. The Rvk value and MRR were founded to be in relation with 4 > 1 > 7 kgF conditioner load. Hence, this study shows that, 4 kgF applied load by conditioner is most suitable for the pad conditioning during CMP.

  4. Iron trichloride as oxidizer in acid slurry for chemical mechanical polishing of Ge2Sb2Te5

    Science.gov (United States)

    Yan, Wei-Xia; Wang, Liang-Yong; Zhang, Ze-Fang; Liu, Wei-Li; Song, Zhi-Tang

    2014-04-01

    The effect of iron trichloride (FeCl3) on chemical mechanical polishing (CMP) of Ge2Sb2Te5 (GST) film is investigated in this paper. The polishing rate of GST increases from 38 nm/min to 144 nm/min when the FeCl3 concentration changes from 0.01 wt% to 0.15 wt%, which is much faster than 20 nm/min for the 1 wt% H2O2-based slurry. This polishing rate trends are inversely correlated with the contact angle data of FeCl3-based slurry on the GST film surface. Thus, it is hypothesized that the hydrophilicity of the GST film surface is associated with the polishing rate during CMP. Atomic force microscope (AFM) and optical microscope (OM) are used to characterize the surface quality after CMP. The chemical mechanism is studied by potentiodynamic measurements such as Ecorr and Icorr to analyze chemical reaction between FeCl3 and GST surface. Finally, it is verified that slurry with FeCl3 has no influence on the electrical property of the post-CMP GST film by the resistivity-temperature (RT) tests.

  5. Preparation and certification of the Polish reference material `Oriental Tobacco Leaves` (CTA-OTL-1) for inorganic trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Dybczynski, R.; Polkowska-Motrenko, H.; Samczynski, Z.; Szopa, Z. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    1996-12-31

    A new Polish certified reference material `Oriental Tobacco Leaves` (CTA-OTL-1) for inorganic trace analysis was prepared. Fresh tobacco leaves of variety `Oriental` were dried, ground and sieved. All precautions were taken to avoid contamination of material with metals. The next step was homogenization. Preliminary homogeneity checking consisted in determining of Ca, Fe and K content by X-ray fluorescence. Final homogeneity testing was performed by neutron activation analysis determining Co, Cr, Fe and Rb. To assure long-term stability, the whole lot of material was sterilized by electron beam radiation. Certification of the candidate reference material was done on the basis of world-wide interlaboratory comparisons exercise in which 61 laboratories, using various analytical methods participated. (author). 30 refs, 12 tabs, 21 figs.

  6. Effects of surface orientation, fluid chemistry and mechanical polishing on the variability of dolomite dissolution rates

    Science.gov (United States)

    Saldi, Giuseppe D.; Voltolini, Marco; Knauss, Kevin G.

    2017-06-01

    Recent studies of carbonate surface reactivity have underscored the fundamental variability of dissolution rates and the heterogeneous distribution of the reaction over the mineral surface due to the inhomogeneous distribution of surface energy. Dolomite dissolution rates relative to different cleavage planes (r-planes) and surfaces cut approximately perpendicular to the c-axis (c-planes) were studied at 50 °C as a function of pH (3.4 ≤ pH ≤ 9.0) and solution composition by vertical scanning interferometry (VSI) and atomic force microscopy (AFM), with the aim of providing an estimate of the intrinsic rate variation of dolomite single crystals and describing the surface reaction distribution and the rate controlling mechanisms. Surface normal retreat rates measured under acidic conditions increased linearly with time and were not visibly affected by the parallel increase of surface roughness. Mean total dissolution rates of r-planes decreased by over 200 times from pH 3.4 to pH 9.0 and CO32--rich solutions, whereas corresponding rate variations spanned over 3 orders of magnitude when also c-plane rate distributions were included in the analysis. At acid to near neutral pH, c-planes dissolved ∼ three times faster than the adjoining r-planes but slower at basic pH and high total carbon concentration, displaying a distinctive morphologic evolution in these two regimes. The comparison of polished and unpolished crystals showed that polished cleavage planes dissolved about three times faster than the unpolished counterpart at near neutral to basic conditions, whereas no significant difference in reactivity was observed at pH topography over the course of the reaction, the evolution of the entire crystal morphology depends also on the reactivity of edge and corner regions, whose contribution to measured rates is not generally taken into account by laboratory experiments. The study of time-dependent mineral morphology and reactivity requires an integrated approach

  7. Reduction of Residual Stresses in Sapphire Cover Glass Induced by Mechanical Polishing and Laser Chamfering Through Etching

    Directory of Open Access Journals (Sweden)

    Shih-Jeh Wu

    2016-10-01

    Full Text Available Sapphire is a hard and anti-scratch material commonly used as cover glass of mobile devices such as watches and mobile phones. A mechanical polishing using diamond slurry is usually necessary to create mirror surface. Additional chamfering at the edge is sometimes needed by mechanical grinding. These processes induce residual stresses and the mechanical strength of the sapphire work piece is impaired. In this study wet etching by phosphate acid process is applied to relief the induced stress in a 1” diameter sapphire cover glass. The sapphire is polished before the edge is chamfered by a picosecond laser. Residual stresses are measured by laser curvature method at different stages of machining. The results show that the wet etching process effectively relief the stress and the laser machining does not incur serious residual stress.

  8. Adsorption treatment of oxide chemical mechanical polishing wastewater from a semiconductor manufacturing plant by electrocoagulation

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Wei-Lung, E-mail: wlchou@sunrise.hk.edu.tw [Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 34, Chung-Chie Road, Sha-Lu, Taichung 433, Taiwan (China); Wang, Chih-Ta [Department of Safety Health and Environmental Engineering, Chung Hwa University of Medical Technology, Tainan Hsien 717, Taiwan (China); Chang, Wen-Chun; Chang, Shih-Yu [Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 34, Chung-Chie Road, Sha-Lu, Taichung 433, Taiwan (China)

    2010-08-15

    In this study, metal hydroxides generated during electrocoagulation (EC) were used to remove the chemical oxygen demand (COD) of oxide chemical mechanical polishing (oxide-CMP) wastewater from a semiconductor manufacturing plant by EC. Adsorption studies were conducted in a batch system for various current densities and temperatures. The COD concentration in the oxide-CMP wastewater was effectively removed and decreased by more than 90%, resulting in a final wastewater COD concentration that was below the Taiwan discharge standard (100 mg L{sup -1}). Since the processed wastewater quality exceeded the direct discharge standard, the effluent could be considered for reuse. The adsorption kinetic studies showed that the EC process was best described using the pseudo-second-order kinetic model at the various current densities and temperatures. The experimental data were also tested against different adsorption isotherm models to describe the EC process. The Freundlich adsorption isotherm model predictions matched satisfactorily with the experimental observations. Thermodynamic parameters, including the Gibbs free energy, enthalpy, and entropy, indicated that the COD adsorption of oxide-CMP wastewater on metal hydroxides was feasible, spontaneous and endothermic in the temperature range of 288-318 K.

  9. Surface modification of ceria nanoparticles and their chemical mechanical polishing behavior on glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zefang, E-mail: zfzhang@mail.sim.ac.cn [State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Shanghai Xinanna Electronic Technology Co., Ltd., Shanghai 201506 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Yu Lei [State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Liu Weili, E-mail: rabbitlwl@mail.sim.ac.cn [State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Shanghai Xinanna Electronic Technology Co., Ltd., Shanghai 201506 (China); Song Zhitang [State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Shanghai Xinanna Electronic Technology Co., Ltd., Shanghai 201506 (China)

    2010-04-01

    To improve their chemical mechanical polishing (CMP) performance, ceria nanoparticles were surface modified with {gamma}-aminopropyltriethoxysilane (APS) through silanization reaction with their surface hydroxyl group. The compositions, structures and dispersibility of the modified ceria particles were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), laser particle size analyzer, zeta potential measurement and stability test, respectively. The results indicated that APS had been successfully grafted onto the surface of ceria nanoparticles, which led to the modified ceria nanoparticles with better dispersibility and stability than unmodified ceria particles in aqueous fluids. Then, CMP performance of the modified ceria nanoparticles on glass substrate was investigated. Experimental results showed that the modified ceria particles exhibited lower material removal rate (MRR) but much better surface quality than unmodified ceria particles, which may be explained by the hardness reduction of ceria particles, the enhancement of lubrication of the particles and substrate surfaces, and the elimination of the agglomeration among the ceria particles.

  10. Preparation of high performance ceramic tiles using waste tile granules and ceramic polishing powder

    Institute of Scientific and Technical Information of China (English)

    WANG Gong-xun; SU Da-gen

    2008-01-01

    This paper presents an innovative approach to reusing waste tile granules (TG) and ceramic polishing powder (PP) to produce high performance ceramic tiles. We studied formulations each with a TG mass fraction of 25.0% and a different PP mass fraction between 1.0% and 7.0%. The formulations included a small amount of borax additive of a mass fracton between 0.2%and 1.2%. The effects of these industrial by-products on compressive strength, water absorption and microstructure of the new ceramic tiles were investigated. The results indicate that the compressive strength decreases and water absorption increases when TG with a mass fraction of 25.0% are added. Improvement of the compressive strength may be achieved when TG (up to 25.0%)and PP (up to 2.0%) are both used at the same time. In particular, the compressive strength improvement can be maximized and water absorption reduced when a borax additive of up to 0.5% is used as a flux. Scanning electron microscopy reveals that a certain amount of fine PP granules and a high content of fluxing oxides from borax avail the formation of glassy phase that fills up the pores in the new ceramic tiles, resulting in a dense product with high compressive strength and low water absorption.

  11. The way to zeros: The future of semiconductor device and chemical mechanical polishing technologies

    Science.gov (United States)

    Tsujimura, Manabu

    2016-06-01

    For the last 60 years, the development of cutting-edge semiconductor devices has strongly emphasized scaling; the effort to scale down current CMOS devices may well achieve the target of 5 nm nodes by 2020. Planarization by chemical mechanical polishing (CMP), is one technology essential for supporting scaling. This paper summarizes the history of CMP transitions in the planarization process as well as the changing degree of planarity required, and, finally, introduces innovative technologies to meet the requirements. The use of CMP was triggered by the replacement of local oxidation of silicon (LOCOS) as the element isolation technology by shallow trench isolation (STI) in the 1980s. Then, CMP’s use expanded to improving embedability of aluminum wiring, tungsten (W) contacts, Cu wiring, and, more recently, to its adoption in high-k metal gate (HKMG) and FinFET (FF) processes. Initially, the required degree of planarity was 50 nm, but now 0 nm is required. Further, zero defects on a post-CMP wafer is now the goal, and it is possible that zero psi CMP loading pressure will be required going forward. Soon, it seems, everything will have to be “zero” and perfect. Although the process is also chemical in nature, the CMP process is actually mechanical with a load added using slurry particles several tens of nm in diameter. Zero load in the loading process, zero nm planarity with no trace of processing, and zero residual foreign material, including the very slurry particles used in the process, are all required. This article will provide an overview of how to achieve these new requirements and what technologies should be employed.

  12. XPS, UV–vis spectroscopy and AFM studies on removal mechanisms of Si-face SiC wafer chemical mechanical polishing (CMP)

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yan [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Pan, Guoshun, E-mail: pangs@tsinghua.edu.cn [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Shi, Xiaolei; Xu, Li; Zou, Chunli; Gong, Hua; Luo, Guihai [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

    2014-10-15

    Highlights: • CMP removal mechanism of Si-face SiC wafer is investigated through XPS analysis. • UV–vis spectroscopy is used to study CMP removal mechanisms. • CMP removal model of Si-face SiC wafer is proposed. • The variations of atomic step morphology on ultra-smooth surface via AFM is studied. - Abstract: Chemical mechanical polishing (CMP) removal mechanisms of on-axis Si-face SiC wafer have been investigated through X-ray photoelectron spectroscopy (XPS), UV–visible (UV–vis) spectroscopy and atomic force microscopy (AFM). XPS results indicate that silicon oxide is formed on Si-face surface polished by the slurry including oxidant H{sub 2}O{sub 2}, but not that after immersing in H{sub 2}O{sub 2} solution. UV–vis spectroscopy curves prove that • OH hydroxyl radical could be generated only under CMP polishing by the slurry including H{sub 2}O{sub 2} and abrasive, so as to promote oxidation of Si-face to realize the effective removal; meanwhile, alkali KOH during CMP could induce the production of more radicals to improve the removal. On the other side, ultra-smooth polished surface with atomic step structure morphology and extremely low Ra of about 0.06 nm (through AFM) is obtained using the developed slurry with silica nanoparticle abrasive. Through investigating the variations of the atomic step morphology on the surface polished by different slurries, it's reveals that CMP removal mechanism involves a simultaneous process of surface chemical reaction and nanoparticle atomic scale abrasion.

  13. Investigation on the surface characterization of Ga-faced GaN after chemical-mechanical polishing

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Hua [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Pan, Guoshun, E-mail: pangs@tsinghua.edu.cn [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Zhou, Yan; Shi, Xiaolei; Zou, Chunli; Zhang, Suman [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

    2015-05-30

    Highlights: • Tiny-sized nanoparticles were introduced in GaN CMP to realize a good surface. • The relationship between surface characterization and abrasive size was conducted. • An atomic step-terrace structure was achieved on GaN surface after CMP. • Pt/C catalyst nanoparticles were used in GaN CMP to get a higher MRR. - Abstract: The relationship between the surface characterization after chemical mechanical polishing (CMP) and the size of the silica (SiO{sub 2}) abrasive used for CMP of gallium nitride (GaN) substrates was investigated in detail. Atomic force microscope was used for measuring the surface morphology, pit feature, pit depth distribution, and atomic step-terrace structure. With the decrease of SiO{sub 2} abrasive size, the pit depth reduced and the atomic step-terrace structure became more whole with smaller damage area, resulting in smaller roughness. For tiny-sized SiO{sub 2} abrasive, an almost complete atomic step-terrace structure with 0.0523 nm roughness was achieved. On the other hand, in order to acquire higher removal, Pt/C nanoparticle was employed as a catalyst in CMP slurry. The result indicates that when Pt/C catalyst content was reached to 1.0 ppm, material removal rate was increased by 47.69% compared to that by none of the catalyst, and besides, the pit depth reduced and the surface atomic step-terrace structure was not destroyed. The Pt/C nanoparticle is proved to be the promising catalyst to the surface preparation of super-hard and inert materials with high efficiency and good surface.

  14. Gallic Acid as a Complexing Agent for Copper Chemical Mechanical Polishing Slurries at Neutral pH

    Science.gov (United States)

    Kim, Yung Jun; Kang, Min Cheol; Kwon, Oh Joong; Kim, Jae Jeong

    2011-05-01

    Gallic acid was investigated as a new complexing agent for copper (Cu) chemical mechanical polishing slurries at neutral pH. Addition of 0.03 M gallic acid and 1.12 M H2O2 at pH 7 resulted in a Cu removal rate of 560.73±17.49 nm/min, and the ratio of the Cu removal rate to the Cu dissolution rate was 14.8. Addition of gallic acid improved the slurry performance compared to glycine addition. X-ray photoelectron spectroscopy analysis and contact angle measurements showed that addition of gallic acid enhanced the Cu polishing behavior by suppressing the formation of surface Cu oxide.

  15. Standards of Conditions During Preparations for the Summer Paralympic Games Between 2004 and 2012 Assessed by Polish Athletes

    Directory of Open Access Journals (Sweden)

    Sobiecka Joanna

    2015-12-01

    Full Text Available The quality of training conditions affects sporting success, injuries and health. The aim of the work was to present the conditions during the preparations of Polish athletes for the Summer Paralympic Games 2004-2012. The study encompassed 271 paralympians: Athens (91, Beijing (89 and London (91, competing in 13 disciplines. The research was based on a two-part questionnaire by Kłodecka-Różalska adjusted for disabled sports, and was conducted one month before each PG. Part 1 contained 20 closed-ended questions regarding conditions during preparations, while Part 2 concerned socio-demographic and sports-related data. Three levels of conditions: good, satisfactory and poor, were identified. The analysis showed that while the relationships between the athletes were good in all the preparatory periods, the co-operation with the paralympic coaches worsened. The standards of accommodation, food and sports facilities lowered. Personal orthopaedic supply was satisfactory in London; personal sporting equipment was good at all PG. The quality of medical care was the highest in London. The co-operation with physicians, physiotherapists and massage therapists was satisfactory. Consultations with the dietician were sporadic and assessed as poor. Psychological consultations were rare but satisfactory in Beijing and London. Contacts with the mass media were poor at all PG. Although combining private life, work, and education with sport was satisfactory, it was increasingly difficult to manage, particularly before London. The conditions during preparations for the PG 2004-2012 varied. Improvement was noticed only in the quality of medical care and personal orthopaedic supply.

  16. Structural and chemical characteristics of atomically smooth GaN surfaces prepared by abrasive-free polishing with Pt catalyst

    Science.gov (United States)

    Murata, Junji; Sadakuni, Shun; Okamoto, Takeshi; Hattori, Azusa N.; Yagi, Keita; Sano, Yasuhisa; Arima, Kenta; Yamauchi, Kazuto

    2012-06-01

    This paper reports the structural and chemical characteristics of atomically flat gallium nitride (GaN) surfaces prepared by abrasive-free polishing with platinum (Pt) catalyst. Atomic force microscopy revealed regularly alternating wide and narrow terraces with a step height equivalent to that of a single bilayer on the flattened GaN surfaces, which originate from the differences in etching rate of two neighboring terraces. The material removal characteristics of the method for GaN surfaces were investigated in detail. We confirmed that an atomically smooth GaN surface with an extremely small number of surface defects, including pits and scratches, can be achieved, regardless of the growth method, surface polarity, and doping concentration. X-ray photoelectron spectroscopy showed that the flattening method produces clean GaN surfaces with only trace impurities such as Ga oxide and metallic Ga. Contamination with the Pt catalyst was also evaluated using total-reflection X-ray fluorescence analysis. A wet cleaning method with aqua regia is proposed, which markedly eliminates this Pt contamination without affecting the surface morphology.

  17. R&D progress in SRF surface preparation with centrifugal barrel polishing (cbp) for both Nb and Cu

    Energy Technology Data Exchange (ETDEWEB)

    Palczewski, Ari [JLAB

    2013-09-01

    Centrifugal Barrel polishing (CBP) is becoming a common R&D tool for SRF cavity preparation around the world. During the CBP process a cylindrically symmetric SRF cavity is filled with relatively cheap and environmentally friendly abrasive and sealed. The cavity is then spun around a cylindrically symmetric axis at high speeds uniformly conditioning the inner surface. This uniformity is especially relevant for SRF application because many times a single manufacturing defects limits cavity?s performance well below it?s theoretical limit. In addition CBP has created surfaces with roughness?s on the order of 10?s of nm which create a unique surface for wet chemistry or thin film deposition. CBP is now being utilized at Jefferson Laboratory, Fermi Laboratory and Cornell University in the US, Deutsches Elektronen-Synchrotron in Germany, Laboratori Nazionali di Legnaro in Italy, and Raja Ramanna Centre for Advanced Technology in India. In this talk we will present current CBP research from each lab including equipment, baseline recipes, cavity removal rates and subsequent cryogenic cavity tests on niobium as well as copper cavities where available.

  18. Corrosion electrochemical mechanism of chemical mechanical polishing of copper in K3Fe(CN)6 solution

    Institute of Scientific and Technical Information of China (English)

    何捍卫; 胡岳华; 黄可龙

    2002-01-01

    Polarization curves of copper were measured in NH3*H2O media containing K3Fe(CN)6. Components of passive film were analyzed by XPS. Relation of polishing rate with corrosion current density was investigated during CMP. Copper can be passivated in the slurry and main component of passive film is Cu4Fe(CN)6. Relation of polishing rate with corrosion current density is linear direct ratio and expressed as R=KJcorr during CMP. Coefficient K varies with different slurry systems but is constant under experimental conditions, which does not vary with NH3*H2O, K3Fe(CN)6, γ-Al2O3 concentrations, polishing pressures and rotative rate in a slurry system during CMP.

  19. Characterization of wet pad surface in chemical mechanical polishing (CMP) process with full-field optical coherence tomography (FF-OCT).

    Science.gov (United States)

    Choi, Woo June; Jung, Sung Pyo; Shin, Jun Geun; Yang, Danning; Lee, Byeong Ha

    2011-07-04

    Chemical mechanical polishing (CMP) is a key process for global planarization of silicon wafers for semiconductors and AlTiC wafers for magnetic heads. Removal rate of wafer material is directly dependent on the surface roughness of a CMP pad, thus the structure of the pad surface has been evaluated with variable techniques. However, under in situ CMP process, the measurements have been severely limited due to the existence of polishing fluids including the slurry on the pad surface. In here, we newly introduce ultra-high resolution full-field optical coherence tomography (FF-OCT) to investigate the surface of wet pads. With FF-OCT, the wet pad surface could be quantitatively characterized in terms of the polishing pad lifetime, and also be three-dimensionally visualized. We found that reasonable polishing span could be evaluated from the surface roughness measurement and the groove depth measurement made by FF-OCT.

  20. Position paper prepared by the Section of Immunotherapy, Polish Society of Allergy

    Directory of Open Access Journals (Sweden)

    Marek Jutel

    2015-12-01

    Full Text Available SLIT ([i]sublingual immunotherapy[/i], induces allergen-specific immune tolerance by sublingual administration of a gradually increasing dose of an allergen. The mechanism of SLIT is comparable to those during SCIT (subcutaneous immunotherapy, with the exception of local oral dendritic cells, pre-programmed to elicit tolerance. In the SLIT dose, to achieve the same efficacy as in SCIT, it should be 50–100 times higher with better safety profile. The highest quality evidence supporting the efficacy of SLIT lasting 1 – 3 years has been provided by the large scale double-blind, placebo-controlled (DBPC trials for grass pollen extracts, both in children and adults with allergic rhinitis. Current indications for SLIT are allergic rhinitis (and conjunctivitis in both children and adults sensitized to pollen allergens (trees, grass, [i]Parietaria[/i], house dust mites ([i]Dermatophagoides pteronyssinus, Dermatophagoides farinae[/i], cat fur, as well as mild to moderate controlled atopic asthma in children sensitized to house dust mites. There are positive findings for both asthma and new sensitization prevention. Severe adverse events, including anaphylaxis, are very rare, and no fatalities have been reported. Local adverse reactions develop in up to 70 – 80% of patients. Risk factors for SLIT adverse events have not been clearly identified. Risk factors of non-adherence to treatment might be dependent on the patient, disease treatment, physician-patient relationship, and variables in the health care system organization.

  1. Use the Polishing Tile Waste to Prepare Thermal Insulation Ceramic Tile%抛光废料制备隔热保温陶瓷砖

    Institute of Scientific and Technical Information of China (English)

    刘华锋; 曾令可; 王慧; 冼志勇

    2014-01-01

    抛光废渣产生量大,回收利用率低,研究大量利用抛光废渣的新途径不仅能解决抛光废渣的处理问题,也将带来巨大的经济效益。本文分析了利用抛光废渣制备隔热保温陶瓷砖的背景、废弃原料处理、抛光渣发泡原理、制备工艺、性能影响因素等。%The production of polishing tile waste is so huge ,while with a low Recovery utilization rate. Research a new way that consuming a huge mass of polishing tile waste can not only solve the problem of waste processing ,but also produce huge economic benefits. This paper analyzed the back-ground ,the waste raw material processing ,the foaming principle ,the preparation technology ,the properties affecting factors of Preparation of Thermal Insulation ceramic tile with Polishing tile Waste.

  2. Mechanical bowel preparation for elective colorectal surgery

    DEFF Research Database (Denmark)

    Güenaga, Katia F; Matos, Delcio; Wille-Jørgensen, Peer

    2011-01-01

    The presence of bowel contents during colorectal surgery has been related to anastomotic leakage, but the belief that mechanical bowel preparation (MBP) is an efficient agent against leakage and infectious complications is based on observational data and expert opinions only.An enema before...... the rectal surgery to clean the rectum and facilitate the manipulation for the mechanical anastomosis is used for many surgeons. This is analysed separately...

  3. Mechanical bowel preparation for elective colorectal surgery

    DEFF Research Database (Denmark)

    Güenaga, Katia F; Matos, Delcio; Wille-Jørgensen, Peer

    2011-01-01

    The presence of bowel contents during colorectal surgery has been related to anastomotic leakage, but the belief that mechanical bowel preparation (MBP) is an efficient agent against leakage and infectious complications is based on observational data and expert opinions only.An enema before the r...... the rectal surgery to clean the rectum and facilitate the manipulation for the mechanical anastomosis is used for many surgeons. This is analysed separately...

  4. Mechanical site preparation for forest restoration

    Science.gov (United States)

    Magnus Lof; Daniel C. Dey; Rafael M. Navarro; Douglass F. Jacobs

    2012-01-01

    Forest restoration projects have become increasingly common around the world and planting trees is almost always a key component. Low seedling survival and growth may result in restoration failures and various mechanical site preparation techniques for treatment of soils and vegetation are important tools used to help counteract this. In this article, we synthesize the...

  5. Control of adhesion force between ceria particles and polishing pad in shallow trench isolation chemical mechanical planarization.

    Science.gov (United States)

    Seo, Jihoon; Moon, Jinok; Bae, Jae-Young; Yoon, Kwang Seob; Sigmund, Wolfgang; Paik, Ungyu

    2014-06-01

    The adhesion force between ceria and polyurethane (PU) pad was controlled to remove the step height from cell region to peripheral region during Shallow Trench Isolation Chemical Mechanical Planarization (STI-CMP) for NAND flash. Picolinic acid was found to be adsorbed on ceria particles at pH 4.5 following a Langmuir isotherm with the maximum adsorbed amount of 0.36 mg/m2. The ceria suspension with full surface coverage of picolinic acid showed a threefold increase in the number of adhered ceria particles on the PU pad over non-coated ceria particles. It was shown that the coverage percent of picolinic acid on ceria corresponds well with the amount percent of adsorbed ceria on PU pad. The change in adsorbed particles was directly reflected in the CMP polishing process where significant improvements were achieved. Particularly, convex areas on the chip experienced higher friction force from the attached abrasives on the PU pad than concave areas. As a result, the convex areas have increased removal rate of step height compared to the ceria suspension without picolinic acid. The changing profiles of convex areas are reported during the step height reduction as a function of polishing time.

  6. Chemical mechanical polishing of Indium phosphide, Gallium arsenide and Indium gallium arsenide films and related environment and safety aspects

    Science.gov (United States)

    Matovu, John Bogere

    As scaling continues with advanced technology nodes in the microelectronic industry to enhance device performance, the performance limits of the conventional substrate materials such as silicon as a channel material in the front-end-of-the-line of the complementary metal oxide semiconductor (CMOS) need to be surmounted. These challenges have invigorated research into new materials such as III-V materials consisting of InP, GaAs, InGaAs for n-channel CMOS and Ge for p-channels CMOS to enhance device performance. These III-V materials have higher electron mobility that is required for the n-channel while Ge has high hole mobility that is required for the p-channel. Integration of these materials in future devices requires chemical mechanical polishing (CMP) to achieve a smooth and planar surface to enable further processing. The CMP process of these materials has been associated with environment, health and safety (EH&S) issues due to the presence of P and As that can lead to the formation of toxic gaseous hydrides. The safe handling of As contaminated consumables and post-CMP slurry waste is essential. In this work, the chemical mechanical polishing of InP, GaAs and InGaAs films and the associated environment, health and safety (EH&S) issues are discussed. InP removal rates (RRs) and phosphine generation during the CMP of blanket InP films in hydrogen peroxide-based silica particle dispersions in the presence and absence of three different multifunctional chelating carboxylic acids, namely oxalic acid, tartaric acid, and citric acid are reported. The presence of these acids in the polishing slurry resulted in good InP removal rates (about 400 nm min-1) and very low phosphine generation (slurry compositions consisting of 3 wt % silica, 1 wt % hydrogen peroxide and 0.08 M oxalic acid or citric acid that provided the best results on blanket InP films were used to evaluate their planarization capability of patterned InP-STI structures of 200 mm diameter wafers. Cross

  7. Preparation and certification of the Polish reference material Virginia Tobacco Leaves (CTA-VTL-2) for inorganic trace analysis including microanalysis

    Energy Technology Data Exchange (ETDEWEB)

    Dybczynski, R.; Polkowska-Motrenko, H.; Samczynski, Z.; Szopa, Z.

    1997-12-31

    A new Polish certified reference material Virginia Tobacco Leaves (CTA-VTL-2) for inorganic trace analysis including microanalysis has been prepared. Certification of the candidate reference material was based on the world-wide interlaboratory comparison in which 60 laboratories from 18 countries, participated using various analytical methods and techniques. Data evaluation performed by means of the new multifunctional software package -SSQC. Recommended values were assigned for 33 and `information` values for 10 elements, respectively. The validity of `certified` values was confirmed for several elements using `very accurate` methods developed in this Laboratory. (author). 47 refs, 28 figs, 12 tabs.

  8. The Family Meeting as a Mechanism of Family Governance: Review of the Experiences of Polish Family Companies

    Directory of Open Access Journals (Sweden)

    Izabela Koładkiewicz

    2014-09-01

    Full Text Available Purpose: The objective of the research was an assessment of the experiences of Polish owners of family companies in organizing family meetings as mechanisms of family governance as well as evaluating the usefulness of solutions developed in this sphere for both family and company. Methodology: The character of the conducted research was qualitative. The main technique used to gather data involved interviews. A total of thirty nine respondents from twenty companies were questioned. Nineteen were representatives of the older generation while twenty represented the younger second generation of owners of family businesses. Findings: Research results indicated the rather extensive use by the examined owner families of family meetings to discuss company matters. Depending on their needs, they developed various models ranging from the ad hoc bringing up of company matters to the transformation of such meetings into formal, family meetings of the management board organized in company offi ces. Regardless of organizational form, family meetings were an important forum for the exchange of information and views on the functioning of the company among family members. The experiences of the examined families of owners in building family governance systems, understood as a complex of structures and mechanisms making possible the maintenance of a balance between tensions stemming from economic and emotional ties among family members, both involved in the company and outside it, remain small. Research limitations: The qualitative character of the research, including the size of the examined sample (twenty family companies represented by thirty nine representatives, means that the generalizations made for the purposes of this study refer only to the experiences and opinions of the interviewed respondents. Originality: The research performed is the fi rst of its kind devoted to family meetings as a component of the system of family governance created in the

  9. Mechanical bowel preparation for elective colorectal surgery

    DEFF Research Database (Denmark)

    Guenaga, Katia K F G; Matos, Delcio; Wille-Jørgensen, Peer

    2009-01-01

    BACKGROUND: The presence of bowel contents during surgery has been related to anastomotic leakage, but the belief that mechanical bowel preparation (MBP) is an efficient agent against leakage and infectious complications is based on observational data and expert opinions only. OBJECTIVES: To dete......BACKGROUND: The presence of bowel contents during surgery has been related to anastomotic leakage, but the belief that mechanical bowel preparation (MBP) is an efficient agent against leakage and infectious complications is based on observational data and expert opinions only. OBJECTIVES...... with no MBP. Primary outcomes included anastomosis leakage - both rectal and colonic - and combined figures. Secondary outcomes included mortality, peritonitis, reoperation, wound infection, extra-abdominal complications, and overall surgical site infections. DATA COLLECTION AND ANALYSIS: Data were...

  10. Mechanism analysis on finishing of reaction-sintered silicon carbide by combination of water vapor plasma oxidation and ceria slurry polishing

    Science.gov (United States)

    Shen, Xinmin; Tu, Qunzhang; Deng, Hui; Jiang, Guoliang; Yamamura, Kazuya

    2015-05-01

    Reaction-sintered silicon carbide (RS-SiC), which is considered as a promising mirror material for space telescope systems, requires a high surface property. An ultrasmooth surface with a Ra surface roughness of 0.480 nm was obtained after water vapor plasma oxidation for 90 min followed by ceria slurry polishing for 40 min. The oxidation process of RS-SiC by water vapor plasma was analyzed based on the Deal-Grove model, and the theoretical calculation results are consistent with the measured data obtained by scanning white light interferometer (SWLI), scanning electron microscopy/energy-dispersive x-ray, and atomic force microscope. The polishing process of oxidized RS-SiC by ceria slurry was investigated according to the Preston equation, which would theoretically forecast the evolutions of RS-SiC surfaces along with the increasing of polishing time, and it was experimentally verified by comparing the surface roughnesses obtained by SWLI and the surface morphologies obtained by SEM. The mechanism analysis on the finishing of RS-SiC would be effective for the optimization of water vapor plasma oxidation parameters and ceria slurry polishing parameters, which will promote the application of RS-SiC substrates by improving the surface property obtained by the oxidation-assisted polishing method.

  11. The effect of mechanical load cycling and polishing time on microleakage of class V glass-ionomer and composite restorations: A scanning electron microscopy evaluation

    Directory of Open Access Journals (Sweden)

    Mansoreh Mirzaie

    2014-01-01

    Full Text Available Background: Microleakage is one of the challenging concerns in direct filling restorations. Understanding of its related factors is important in clinical practice. The aim of this study was scanning electron microscopy (SEM evaluation of marginal integrity in three types of tooth-colored restorative materials in class V cavity preparations and the effect of load cycling and polishing time on the microleakage. Materials and Methods: In this in vitro experimental study, class V cavity preparations were prepared on the buccal and lingual surfaces of 60 bovine incisors. The specimens were divided into three groups each containing 20 teeth: group 1: Filtek Z350, Group 2: Fuji IX/G Coat Plus, Group 3: Fuji II LC/GC varnish. In each group, 2 subgroups (n = 20 were established based on finishing time (immediate or delayed by 24 h. All specimens were thermocycled (×2,000, 5-50°C. In each sub groups, half of the teeth were load cycled. Epoxy resin replicas of 24 specimens were evaluated under field emission-SEM and interfacial gaps were measured. All teeth were then immersed in 0.5% basic fuchsin dye for 24 h, sectioned and observed under stereomicroscope. Data were analyzed with Kruskal-Wallis′ test and Mann-Whitney U test and a comparison between incisal and cervical microleakage was made with Wilcoxon test. P < 0.05 was considered as significant. Results: Load cycling and filling material had a significant effect on microleakage, but polishing time did not. Cervical microleakage in Z350/load cycle/immediate polish and Fuji IX/load cycle/immediate or delayed polish and Fuji IX/no load cycle/immediate polish were significantly higher than incisal microleakage. Conclusion: It was concluded that the cervical sealing ability of Fuji IX under load cycling was better than Fuji II LC. Under load cycling and immediate polishing Z350 showed better marginal integrity than both Fuji II LC and Fuji IX. The immediate polishing didn′t cause a statistically

  12. A nano-scale mirror-like surface of Ti-6Al-4V attained by chemical mechanical polishing

    Science.gov (United States)

    Chenliang, Liang; Weili, Liu; Shasha, Li; Hui, Kong; Zefang, Zhang; Zhitang, Song

    2016-05-01

    Metal Ti and its alloys have been widely utilized in the fields of aviation, medical science, and micro-electro-mechanical systems, for its excellent specific strength, resistance to corrosion, and biological compatibility. As the application of Ti moves to the micro or nano scale, however, traditional methods of planarization have shown their short slabs. Thus, we introduce the method of chemical mechanical polishing (CMP) to provide a new way for the nano-scale planarization method of Ti alloys. We obtain a mirror-like surface, whose flatness is of nano-scale, via the CMP method. We test the basic mechanical behavior of Ti-6Al-4V (Ti64) in the CMP process, and optimize the composition of CMP slurry. Furthermore, the possible reactions that may take place in the CMP process have been studied by electrochemical methods combined with x-ray photoelectron spectroscopy (XPS). An equivalent circuit has been built to interpret the dynamic of oxidation. Finally, a model has been established to explain the synergy of chemical and mechanical effects in the CMP of Ti-6Al-4V. Project supported by the National Major Scientific and Technological Special Project during the Twelfth Five-year Plan Period of China (Grant No. 2009ZX02030-1), the National Natural Science Foundation of China (Grant No. 51205387), the Support by Science and Technology Commission of Shanghai City, China (Grant No. 11nm0500300), and the Science and Technology Commission of Shanghai City, China (Grant No. 14XD1425300).

  13. Polish visit

    CERN Multimedia

    2003-01-01

    On 6 October, Professor Michal Kleiber, Polish Minister of Science and Chairman of the State Committee for Scientific Research, visited CERN and met both the current and designated Director General, Luciano Maiani and Robert Aymar. Professor Kleiber visited the CMS and ATLAS detector assembly halls, the underground cavern for ATLAS, and the LHC superconducting magnet string test hall. Michal Kleiber (left), Polish minister of science and Jan Krolikowski, scientist at Warsaw University and working for CMS, who shows the prototypes of the Muon Trigger board of CMS.

  14. Experimental Study on the Effects of Alumina Abrasive Particle Behavior in MR Polishing for MEMS Applications

    Directory of Open Access Journals (Sweden)

    Young-Jae Shin

    2008-01-01

    Full Text Available Recently, the magnetorheological (MR polishing process has been examined asa new ultra-precision polishing technology for micro parts in MEMS applications. In theMR polishing process, the magnetic force plays a dominant role. This method uses MRfluids which contains micro abrasives as a polishing media. The objective of the presentresearch is to shed light onto the material removal mechanism under various slurryconditions for polishing and to investigate surface characteristics, including shape analysisand surface roughness measurement, of spots obtained from the MR polishing process usingalumina abrasives. A series of basic experiments were first performed to determine theoptimum polishing conditions for BK7 glass using prepared slurries by changing the processparameters, such as wheel rotating speed and electric current. Using the obtained results,groove polishing was then performed and the results are investigated. Outstanding surfaceroughness of Ra=3.8nm was obtained on the BK7 glass specimen. The present resultshighlight the possibility of applying this polishing method to ultra-precision micro partsproduction, especially in MEMS applications.

  15. Experimental Study of Chemical Mechanical Rough Polishing for Hard Disk Substrate%硬盘基板化学机械粗抛光的实验研究

    Institute of Scientific and Technical Information of China (English)

    刘利宾; 刘玉岭; 王胜利; 林娜娜; 杨立兵

    2011-01-01

    For rough polishing of NiP/Al substrate of hard disk, SiO2 colloid was adopted to polish the substrate of hard disk under different pressures, speed, pH values, abrasive concentration and activator concentration, the removal rate of hard disk substrate was measured and the surface analyses after chemical mechanical rough polishing were accomplished by atomic force microscope (AFM). Finally, five key polishing parameters were optimized. The results show that when the pressure is 0. 10 Mpa, the speed is 80 rad/min, the pH value is 11.2, the ratio of abrasive volume with the deionized water is 1:0. 5, and surfactant concentration is 9 mL/L, the removal rate of hard disk substrate is 27 mg/min, the surface roughness after polishing is 0.281 nm. After rough polishing of hard disk substrate, high removal rate and good surface roughness are obtained, and it will greatly reduce the time of fine polishing, which is beneficial to increase the polishing efficiency.%针对硬盘NiP/Al基板粗抛光,采用SiO2作为抛光磨料的碱性抛光液,在不同压力、转速、pH值、磨料浓度和活性剂体积浓度下,对硬盘基板粗抛光的去除速率和表面粗糙度的变化规律进行研究,用原子力显微镜观察抛光表面的微观形貌.最后对5个关键参数进行了优化.结果表明:当压力为0.10 MPa,转速为80 rad/min,pH值为11.2,磨料与去离子水体积比为1∶0.5,表面活性剂体积浓度为9 mL/L时,硬盘基板的去除速率为27 mg/min,粗抛后表面粗糙度为0.281 nm,获得了高的去除速率和较好的表面粗糙度,这样会大大降低精抛的时间,有利于抛光效率的提高.

  16. Study on the Effects of Corrosion Inhibitor According to the Functional Groups for Cu Chemical Mechanical Polishing in Neutral Environment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Won; Kim, Jae Jeong [Institute of Chemical Process, Seoul National University, Seoul (Korea, Republic of)

    2015-08-15

    As the aluminum (Al) metallization process was replaced with copper (Cu), the damascene process was introduced, which required the planarization step to eliminate over-deposited Cu with Chemical Mechanical Polishing (CMP) process. In this study, the verification of the corrosion inhibitors, one of the Cu CMP slurry components, was conducted to find out the tendency regarding the carboxyl and amino functional group in neutral environment. Through the results of etch rate, removal rate, and chemical ability of corrosion inhibitors based on 1H-1,2,4-triazole as the base corrosion inhibitor, while the amine functional group presents high Cu etching ability, carboxyl functional group shows lower Cu etching ability than base-corrosion inhibitor which means that it increases passivation effect by making strong passivation layer. It implies that the corrosion inhibitor with amine functional group was proper to apply for 1st Cu CMP slurry owing to the high etch rate and with carboxyl functional group was favorable for the 2nd Cu CMP slurry due to the high Cu removal rate/dissolution rate ratio.

  17. Characterization of implant materials in fetal bovine serum and sodium sulfate by electrochemical impedance spectroscopy. I. Mechanically polished samples.

    Science.gov (United States)

    Contu, F; Elsener, B; Böhni, H

    2002-12-01

    Electrochemical impedance spectroscopy is used to monitor the long-term stability (up to 150 days) of mechanically polished commercial pure titanium, Ti6Al4V, Ti6Al7Nb, and CoCrMo alloys in 0.1M sodium sulfate and fetal bovine serum. A capacitive spectrum in the frequency range from 10(-3) to 10(5) Hz is always found and the impedance spectra can be fitted by a simple parallel RC circuit with a constant phase element. The open circuit potential observed in serum is always more cathodic and the polarization resistance (R(p)) is higher than that recorded in sodium sulfate solutions. The observed variation of the equivalent capacitance in serum bovine suggests that an adsorption layer of organic molecules develops on the electrode surface and it is responsible for both the decrease in open circuit potential and the higher R(p), because it hinders the oxygen evolution reaction and the charge transfer responsible for the passive film dissolution (or growth). Among the alloys studied, Ti6Al4V displayed the highest steady-state values of R(p) both in serum and in sodium sulfate.

  18. POLISH FARM MACHINERY MARKET AFTER ACCESSION TO THE EUROPEAN UNION – PRODUCTION AND SUPPLY OF MEANS OF AGRICULTURAL MECHANIZATION

    Directory of Open Access Journals (Sweden)

    Jan Pawlak

    2014-09-01

    Full Text Available After accession to the EU in 2004 the demand for tractors and agricultural implements has grown, followed by increasing supply of them. In 2012, the supply of brand-new agricultural tractors was by 185.4% higher than in 2003. In 2012 the value of renovation index of tractor fleet in agriculture was by 149.3% higher than in 2003. In spite of significant increase of demand for tractors, their production in 2012 was by 39.2% lower than in 2003. The downfall in number of tractors produced in Poland caused that imported tractors achieved more and more important share in supplies on Polish market. In 2003 the share of imports amounted to 64.0% and in 2012 – 91.4%. Production of most other means of agricultural mechanization was in 2012 higher than in 2003. The increase in a case of manure spreaders amounted to 704.3%; self loading or unloading agricultural tractor trailers – 362.1%; fertilizer spreader – 335.2%; field sowing machines – 245.3%; pick-up balers – 222.1% and harvester threshers – 194.8. Decreases were noted in cases of steamers – by 73.3%; potato planters – by 49.7%; harrows other than disc ones – by 42.2%; potato diggers – by 31.2% and rototillers – by 22.8%.

  19. Preparation of wax-emulsion polish for automobile%一种汽车上光乳化蜡的研制

    Institute of Scientific and Technical Information of China (English)

    吴国江

    2011-01-01

    A wax-emulsion polish of automobile was prepared with 58# fully refined paraffin wax,carnauba wax,modified polyethylene and silicone oil.The factors which affected the emulsion stability were specially studied, including ratio of the paraffin wax,carnauba wax and modified polyethylene,type of silicone oil,type of emusifiers and the quantity of abradant.The results shows that one wax-emulsion compareble with the same abroad products for automoble polishing can be prepared,when the quantity of emulsifier is 10%by emulsion mass,emulsifying temperature is at 90±3℃and the emulsifying time is 50 min.%研究了用58#全炼蜡、巴西棕榈蜡、改性聚乙烯蜡、硅油等制备汽车上光乳化蜡的方法。考查了石蜡、巴西棕榈蜡、改性聚乙烯蜡三者的比例、硅油类型、乳化剂类型、摩擦剂用量对乳液性能的影响。实验结果表明,当乳化剂用量为乳液质量的10%,乳化温度为90±3℃,乳化时间为50min,可以制取一种达到国外同类产品水平的汽车上光乳化蜡。

  20. Ultrasonic Polishing

    Science.gov (United States)

    Gilmore, Randy

    1993-01-01

    The ultrasonic polishing process makes use of the high-frequency (ultrasonic) vibrations of an abradable tool which automatically conforms to the work piece and an abrasive slurry to finish surfaces and edges on complex, highly detailed, close tolerance cavities in materials from beryllium copper to carbide. Applications range from critical deburring of guidance system components to removing EDM recast layers from aircraft engine components to polishing molds for forming carbide cutting tool inserts or injection molding plastics. A variety of materials including tool steels, carbides, and even ceramics can be successfully processed. Since the abradable tool automatically conforms to the work piece geometry, the ultrasonic finishing method described offers a number of important benefits in finishing components with complex geometries.

  1. EXPERIMENTAL AND MICRO-IMPACT MECHANISM OF GRINDING HEAD IN POLISHING MACHINE%抛光机磨头微观冲击机理与实验

    Institute of Scientific and Technical Information of China (English)

    邵俊鹏; 徐斌

    2012-01-01

    In order to investigate the microcosmic polishing mechanism ot grlnclmg neaa. Micro impact Mechanism of low/ high speed grinding head were derived. Mathematical modeling of microimpact and amplitude is established. It is concluded that the process of forming ceramic tile defects, by a series of SEM experiments of ceramic tiles. It is concluded that the micro-impact mechanism theory agreement with ceramic tile surface topography is obtained. A series of vibration experiments of grinding head is performed, low speed grinding head can help ceramic tile defects and it can considerably reduce the impact vibration of grinding head at the rough polishing; high speed grinding head so as to effectively enhance the tile surface smoothness at the finish polishing.%为了研究磨头微观加工机理,提出低、高速磨头微观冲击机理。建立微观冲击速度和振幅模型。通过SEM实验得出瓷砖微观缺陷形成过程,并验证了冲击机理理论符合瓷砖表面形貌。通过振动实验得出:粗抛阶段,低速磨头可以减少瓷砖缺陷,降低冲击振动;精抛阶段,高转速磨头可以提高瓷砖的表面质量。

  2. Implications of Polishing Techniques in Quantitative X-Ray Microanalysis

    Science.gov (United States)

    Rémond, Guy; Nockolds, Clive; Phillips, Matthew; Roques-Carmes, Claude

    2002-01-01

    Specimen preparation using abrasives results in surface and subsurface mechanical (stresses, strains), geometrical (roughness), chemical (contaminants, reaction products) and physical modifications (structure, texture, lattice defects). The mechanisms involved in polishing with abrasives are presented to illustrate the effects of surface topography, surface and subsurface composition and induced lattice defects on the accuracy of quantitative x-ray microanalysis of mineral materials with the electron probe microanalyzer (EPMA). PMID:27446758

  3. Coal prep in Brazil: the Polish approach

    Energy Technology Data Exchange (ETDEWEB)

    Zilli, C.B.

    1988-02-01

    With one exception, all coal mined in Brazil is washed at the pit head because of its high dirt content. Since the early 1970s five complete coal preparation plants have been designed and constructed by a consortium, using Polish technology. Among the changes effected by the Polish engineers was the introduction of Polish designed equipment. These have led to several small modifications on the usual flowsheet design, which have increased recoveries. 4 figs.

  4. Investigation on the Electrochemical-Mechanical Polishing of NiP Substrate of Hard Disk%硬盘NiP基板的电化学机械抛光研究

    Institute of Scientific and Technical Information of China (English)

    储向峰; 白林山; 陈同云

    2011-01-01

    利用自制的抛光液和改造的抛光机对NiP基板进行电化学机械抛光,研究了抛光电压、抛光台转速、抛光压力和抛光液流速对材料去除速率的影响,对电化学机械抛光的机理做了初步的分析.研究结果表明,NiP基板可以用低压力(3.5 kPa)抛光,材料的去除速率可以通过调整抛光电压,抛光台转速和抛光液流速进行控制.%NiP basic substrates of hard disks were polished by electrochemical-mechanical polishing (ECMP) method with home-made slurry and a modified polisher.The effects of voltage,table rotation speed,pressure and slurry flow rate on the removal rate were investigated.The electrochemical mechanical polishing mechanism was primarily analyzed.The results show that NiP substrate can be polished with ECMP method at low pressure (3.5 kPa) and the material removal rate (MRR) can be controlled by adjusting polishing voltage,rotation speed of polishing table and slurry flow rate.

  5. Mechanical bowel preparation in elective open colon surgery

    OpenAIRE

    Fa-Si-Oen, Patrick Regnier

    2006-01-01

    Mechanical bowel preparation is a long standing practice in elective open colon surgery dating from the 1970's. It has always been believed to reduce the rate of postoperative complications in the form of anastomotic leakage and wound infection. In this thesis we broadly and thoroughly examine the various aspects and the value of mechanical bowel preparation in elective open colon surgery. - Mechanical bowel preparation in elective open colon surgery does not reduce the rate of anastomotic le...

  6. Self-reported preparation of Polish midwives for independent performance of prophylactic activities within the scope of women’s diseases and obstetric pathologies

    Directory of Open Access Journals (Sweden)

    Grażyna J. Iwanowicz-Palus

    2014-06-01

    Full Text Available objective. The objective of the study is an attempt to recognize self-reported preparation of midwives for an independent performance of prophylactic activities within the scope of women’s diseases and obstetric pathologies. material and methods. The study was conducted in a representative all-Polish population sample of 3,569 midwives, by the method of a diagnostic survey using a questionnaire technique. The research instrument was a questionnaire form designed by the author containing items concerning the characteristics of respondents and the object of the study, constructed based on the 5-point Liker scale. The relationships between the variables were verified using chi-square test (χ [sup]2[/sup] of independence. The p values p<0.05 were considered statistically significant. results. Analysis of results allows the presumption that in the opinions of midwives the majority of them are prepared for the independent performance of prophylactic activities in the area of women’s diseases (84.28% and obstetric pathologies (77.95%. However, nearly every tenth midwife, irrespective of the region of Poland where she lives, age, and participation in post-graduate training, is not prepared for an independent performance of the prevention of women’s diseases. In turn, the lack of preparation for carrying out prevention of women’s diseases was admitted mainly by midwives from the northern and central regions of Poland, aged 31–40, possessing post-secondary school education, who did not participate in any form of post-graduate training. conclusions. The results of studies and analysis of the relevant literature indicate that it is necessary for midwives to improve their qualifications in the area of prophylaxis of women’s diseases and obstetric pathologies through participation in various forms of post-graduate education

  7. Realization basic directions of the Bologna process in preparation of teachers physical cultures in Polish Institutes of higher

    Directory of Open Access Journals (Sweden)

    Pasichnik V.R.

    2010-06-01

    Full Text Available Basic progress of higher school trends are presented in Poland. Directions of introduction of decisions of Bologna declaration and European educational standards are considered in preparation of teachers of physical culture. Information is resulted about the improvement of process of preparation of specialists of physical education and sport in the Warsaw academy of physical education. Growth of the state financing of research projects and introduction of the European educational projects is marked. It renders assistance to perfection of process of training of pedagogical personnels.

  8. Preparation of the microemulsion for automobile polishing wax%一种微乳液型汽车上光蜡的制备

    Institute of Scientific and Technical Information of China (English)

    王冬美; 张建中; 肇薇; 张颖; 安磊

    2011-01-01

    The microemulsion of automobile polishing wax was prepared with Brazil camauba wax,beeswax, paraffin and surfactant as materials.The effect of selection and the amount of the emulsifier, the emulsifying time, the emulsifying temperature, the water of the emulsification and the stirring speed were studied.The results showed the optimal conditions were as follows: the emulsifier was complex 1, the emulsifying time was 30 min, the emulsifying temperature was 90 ℃, the water of the emulsification was 70% , the stirring speed was 1000 r/min.%以巴西棕榈蜡、蜂蜡、石蜡和表面活性剂为原料,制备微乳液型汽车上光蜡,考察了乳化剂选择及用量、乳化时间、乳化温度、乳化用水量、搅拌转速等因素对乳化反应的影响.结果表明,最佳乳化条件为:乳化剂为复配1型,乳化剂的用量为6%,搅拌转速1 000 r/min,乳化时间30 min,乳化温度90℃,乳化用水量为70%.

  9. Synergetic effect of benzotriazole and non-ionic surfactant on copper chemical mechanical polishing in KIO{sub 4}-based slurries

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Liang [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Center for Advanced Materials Processing, Clarkson University, Potsdam, NY 13699 (United States); He, Yongyong [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Niu, Xiangyu; Li, Yuzhuo [Center for Advanced Materials Processing, Clarkson University, Potsdam, NY 13699 (United States); Luo, Jianbin, E-mail: luojb@tsinghua.edu.cn [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2014-05-02

    Ruthenium will be integrated into copper interconnects as a barrier layer in the near future. During the chemical mechanical polishing process of the ruthenium barrier layer, copper polishing performance with barrier slurries is crucial to microchips' final performance. This paper mainly studies the synergetic effect of benzotriazole (BTA) and non-ionic surfactant on copper polishing performance using KIO{sub 4}-based barrier slurries. The results show that, the copper removal rate (RR) and static etching rate increase with increasing concentration of KIO{sub 4} due to the increasing proportion of the Cu–periodate and Cu–iodate compounds like Cu(IO{sub 4}){sub 2} and Cu(IO{sub 3}){sub 2} of the passivating film on the copper surface; the added BTA can further enhance the copper RR instead of suppressing it probably due to the formation of incomplete Cu–BTA thin film. It is demonstrated that the combination of BTA and non-ionic surfactant exhibits excellent performance in suppressing the copper RR to about 200 Å/min, realizing satisfactory copper surface quality and achieving desirable material removal rate selectivity among copper, ruthenium and low-κ dielectrics. The synergetic passivation mechanism of BTA and non-ionic surfactant on the copper surface was investigated. It is proposed that in the presence of KIO{sub 4} as an oxidizer, the added BTA and non-ionic surfactant can form a porous passivating film on the copper surface which is mainly composed of the Cu–BTA complex, the adsorbed non-ionic surfactant and the leftover insoluble copper compounds like Cu(IO{sub 4}){sub 2} and Cu(IO{sub 3}){sub 2}, and then the hydrophobic polypropylene oxide segments of non-ionic surfactant can be effectively absorbed on the hydrophobic Cu–BTA complex as a supplement. The above two parts are integrated into a complete passivating film to protect the copper surface from chemical dissolution and excessive mechanical abrasion. - Highlights: • The copper

  10. Audit Committee Practice in the Polish Listed Stock Companies. Present Situation and Development Perspectives

    Directory of Open Access Journals (Sweden)

    Piotr Szczepankowski

    2012-06-01

    Full Text Available The audit committee is one of the parts of corporate governance mechanism, which is understood as the relationship between corporate managers, directors and the providers of equity, people and institutions who save and invest their capital to earn the return. This study presents survey research results of audit committee activity in Polish public stock companies quoted on the Warsaw Stock Exchange (WSE. The purpose of this paper is to present the audit committee practice in Poland after 2009. The paper shows that the audit committee practice is still the most problematic issue of transitional Polish corporate governance rules. The survey has shown that the corporate needs and its implementation, and communication with listed companies leave a lot of room for improvement. The paper is based on the documents prepared in 2010 by PricewaterhouseCoopers, the Polish Association of Listed Companies and the Polish Institute of Directors.

  11. Laser polishing of niobium for SRF applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Liang; Klopf, J. Michael [JLAB; Reece, Charles E. [JLAB; Kelley, Michael [W& M

    2013-09-01

    Smooth interior surfaces are desired for niobium SRF cavities, now obtained by buffered chemical polish (BCP) and/or electropolish (EP). Laser polishing is a potential alternative, having advantages of speed, freedom from chemistry and in-process inspection. Here we show that laser polishing can produce smooth topography with Power Spectral Density (PSD) measurements similar to that obtained by EP. We studied the influence of the laser power density and laser beam raster rate on the surface topography. These two factors need to be combined carefully to smooth the surface without damaging it. Computational modeling was used to simulate the surface temperature and explain the mechanism of laser polishing.

  12. Vestibule and Cask Preparation Mechanical Handling Calculation

    Energy Technology Data Exchange (ETDEWEB)

    N. Ambre

    2004-05-26

    The scope of this document is to develop the size, operational envelopes, and major requirements of the equipment to be used in the vestibule, cask preparation area, and the crane maintenance area of the Fuel Handling Facility. This calculation is intended to support the License Application (LA) submittal of December 2004, in accordance with the directive given by DOE correspondence received on the 27th of January 2004 entitled: ''Authorization for Bechtel SAIC Company L.L.C. to Include a Bare Fuel Handling Facility and Increased Aging Capacity in the License Application, Contract Number DE-AC28-01R W12101'' (Ref. 167124). This correspondence was appended by further correspondence received on the 19th of February 2004 entitled: ''Technical Direction to Bechtel SAIC Company L.L. C. for Surface Facility Improvements, Contract Number DE-AC28-01R W12101; TDL No. 04-024'' (Ref. 16875 1). These documents give the authorization for a Fuel Handling Facility to be included in the baseline. The limitations of this preliminary calculation lie within the assumptions of section 5 , as this calculation is part of an evolutionary design process.

  13. Preoperative mechanical preparation of the colon: the patient's experience

    Directory of Open Access Journals (Sweden)

    Arodell Malin

    2007-05-01

    Full Text Available Abstract Background Preoperative mechanical bowel preparation can be questioned as standard procedure in colon surgery, based on the result from several randomised trials. Methods As part of a large multicenter trial, 105 patients planned for elective colon surgery for cancer, adenoma, or diverticulitis in three hospitals were asked to complete a questionnaire regarding perceived health including experience with bowel preparation. There were 39 questions, each having 3 – 10 answer alternatives, dealing with food intake, pain, discomfort, nausea/vomiting, gas distension, anxiety, tiredness, need of assistance with bowel preparation, and willingness to undergo the procedure again if necessary. Results 60 patients received mechanical bowel preparation (MBP and 45 patients did not (No-MBP. In the MBP group 52% needed assistance with bowel preparation and 30% would consider undergoing the same preoperative procedure again. In the No-MBP group 65 % of the patients were positive to no bowel preparation. There was no significant difference between the two groups with respect to postoperative pain and nausea. On Day 4 (but not on Days 1 and 7 postoperatively patients in the No-MBP group perceived more discomfort than patients in the MBP group, p = 0.02. Time to intake of fluid and solid food did not differ between the two groups. Bowel emptying occurred significantly earlier in the No-MBP group than in the MBP group, p = 0.03. Conclusion Mechanical bowel preparation is distressing for the patient and associated with a prolonged time to first bowel emptying.

  14. Mécanisme de l'usure par polissage des cylindres de moteurs diesel Bore Polishing Wear Mechanism in Diesel Engine Cylinders

    Directory of Open Access Journals (Sweden)

    Fayard J. C.

    2006-11-01

    particulier, l'usure des segments ainsi que les débits de gaz de soufflage, sont plus faibles qu'avec une chemise normale. Enfin, le mécanisme de l'usure par polissage par abrasion douce à deux et à trois corps est parfaitement confirmé par une exploration micrographique et une microanalyse des surfaces polies. A fast and economical method for evaluating lubricants and fuels in relation to the bore polishing wear of super charged diesel-engine cylinders has been developed using a single-cylinder laboratory engine within the framework of an Société Nationale Elf Aquitaine - Institut Français du Pétrole (SNEA-lFP research agreement. This method bears the reference IFP-UP-4/80.It also serves to evaluate the deposit-forming and sticking tendency, ring wear and the oil-consumption tendency of lubricants. It is in good correlation with the CEC-Ford Tornado test and makes an excellent discrimination between the Coordinating European Council (CEC reference cils RL 47 and RL 48. The method is used for investigating the bore polishingwear mechanism by searching for the influence exerted by the principal parameters: (a Composition of the lubricant: the phenomenon is influenced by the base oil and its viscosity, by the amount of polymers improving the viscosity index and especially by the choice of detergent additives. As a first approximation and for homogeneous oil familles, polishing wear increases when the thermal stability of the oil decreases. (b Engine running: polishing increases very fart with the engine load after a certain threshold, and its evolution in time as observed by endoscopic rating shows a characteristic S shape as polishing begins on the thrust side and at the top of the cylinder. (c Composition of the fuel: the increase in the sulfur content of diesel fuel considerably decreases polishing wear caused by an oil reputed to be poorfrom this standpoint but has no effect on a goodoil. (d Surface finish of the cylinder: prepolishing the liner by extremely fine

  15. Evaluation of the effect of polishing on flexural strength of feldspathic porcelain and its comparison with autoglazing and over glazing

    Directory of Open Access Journals (Sweden)

    Jalali H.

    2005-06-01

    Full Text Available Statement of Problem: Ceramic restorations are popular because they can provide the most natural replacement for teeth. However, the brittleness of ceramics is a primary disadvantage. There are various methods for strengthening ceramics such as metal framework, ceramic cores, and surface strengthening mechanisms through glazing, work hardening and ion exchange. Purpose: The purpose of this study was to evaluate the effect of polish on flexural strength of feldspathic porcelain and to compare it with overglaze and autoglaze. Materials and Methods: In this experimental study, one brand of feldspathic porcelain (colorlogic, Ceramco was used and forty bars (25×6×3 mm were prepared according to ISO 6872 and ADA No. 69. The specimens were randomly divided into four groups: overglazed, auto glazed, fine polish and coarse polish (clinic polish. Flexural strength of each specimen was determined by three point bending test (Universal Testing Machine, Zwick 1494, Germany. Collected data was analyzed by ANOVA and post-hoc test with P<0.05 as the limit of significance. Results: A significant difference was observed among the studied groups (P<0.0001. According to post-hoc test, flexural strength in overglaze and fine polish group were significantly stronger than clinic polish and autoglaze group (P<0.001. Although the mean value for overglazed group was higher than fine polish group, this was not statistically significant (P=0.9. Also no statistical difference was seen between autoglazed and coarse polish group (P=0.2. Conclusion: Based on the findings of this study, flexural strength achieved by fine polish (used in this study can compete with overglazing the feldespathic porcelains. It also can be concluded that a final finishing procedure that involves fine polishing may be preferred to simple staining followed by self-glazing.

  16. Evidence for two concurrent inhibitory mechanisms during response preparation

    OpenAIRE

    Duque, Julie; Lew, David; Mazzocchio, Riccardo; Olivier, Etienne; Ivry, Richard B.

    2010-01-01

    Inhibitory mechanisms are critically involved in goal-directed behaviors. To gain further insight into how such mechanisms shape motor representations during response preparation, motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) and H-reflexes were recorded from left hand muscles during choice reaction time tasks. The imperative signal, which indicated the required response, was always preceded by a preparatory cue. During the post-cue delay period, left MEPs...

  17. Mechanical bowel preparation in elective open colon surgery

    NARCIS (Netherlands)

    Fa-Si-Oen, Patrick Regnier

    2006-01-01

    Mechanical bowel preparation is a long standing practice in elective open colon surgery dating from the 1970's. It has always been believed to reduce the rate of postoperative complications in the form of anastomotic leakage and wound infection. In this thesis we broadly and thoroughly examine the v

  18. [Lysenkoism in Polish botany].

    Science.gov (United States)

    Köhler, Piotr

    2008-01-01

    Lysenkoism in Poland was never an autonomous phenomenon. The whole array of reasons for which it appeared in Polish science would require a separate study--here it only needs to be pointed out that the major reasons included terror on the part of the security service, lawlessness, the ubiquitous atmosphere of intimidation and terror, censorship, the diminishing sphere of civil liberties, political show trials, propaganda and denunciations. An important role in facilitating the introduction of Lysenkoism was played also by the reorganization of science after World War Two, the isolation of Polish science from science in the West, as well as the damage it had suffered during the war. At first, Lysenkoism was promoted in Poland by a small group of enthusiastic and uncritical proponents. A overview of the events connected with the ten years of Lysenkoism in Poland (end of 1948--beginning of 1958) shows a two-tier picture of how the 'idea' was propagated. The first tier consisted in the activities of the Association of Marxist Naturalists [Koło Przyrodników-Marksistów], which it engaged in since the end of 1948. The Association was later transformed into a Union of Marxist Naturalists, and this in turn merged, in 1952, with the Copernican Society of Polish Naturalists [Polskie Towarzystwo Przyrodników im. Kopernika]. It was that society which promoted Lysenkoism longest, until the end of 1956. The propaganda and training activities of the circle and the society prepared ground for analogous activities of the newly formed Polish Academy of Science (PAN), which--since its very establishment in 1952--engaged in promoting Lysenkoism through its Second Division. These activities were aimed at naturalists, initially at those who were prominent scientists (eg. the conference at Kuźnice, 1950/1951), and then at those who were only starting their academic career (including national courses in new biology at Dziwnów, 1952, or Kortowo, 1953 and 1955). The end to promoting

  19. Technological Advances of Robot Assisted Polishing

    DEFF Research Database (Denmark)

    Lazarev, Ruslan; Top, Søren; Grønbæk, Jens

    The efficient polishing of surfaces is very important in mould and die industry. Fine abrasive processes are widely used in industry for the first steps for the production of tools of high quality in terms of finishing accuracy, form and surface integrity. While manufacturing of most components...... requires surface finishing in terms of roughness values, the nature of material removal and process mechanics is not clear by fine abrasive finishing on the polishing roughness level. The knowledge and an understanding of the material removal mechanism in fine abrasive processes is a crucial prerequisite....... In this study, the influence of polishing parameters and type of polishing media on fine abrasive surface finishing is investigated. Experimental study is covering 2D rotational surfaces that is widespread used in mould and dies industry. Application of it is essential for process intelligent control, condition...

  20. A Review on Nanofluids: Preparation, Stability Mechanisms, and Applications

    OpenAIRE

    Wei Yu; Huaqing Xie

    2012-01-01

    Nanofluids, the fluid suspensions of nanomaterials, have shown many interesting properties, and the distinctive features offer unprecedented potential for many applications. This paper summarizes the recent progress on the study of nanofluids, such as the preparation methods, the evaluation methods for the stability of nanofluids, and the ways to enhance the stability for nanofluids, the stability mechanisms of nanofluids, and presents the broad range of current and future applications in var...

  1. Preparation and degradation mechanisms of biodegradable polymer: a review

    Science.gov (United States)

    Zeng, S. H.; Duan, P. P.; Shen, M. X.; Xue, Y. J.; Wang, Z. Y.

    2016-07-01

    Polymers are difficult to degrade completely in Nature, and their catabolites may pollute the environment. In recent years, biodegradable polymers have become the hot topic in people's daily life with increasing interest, and a controllable polymer biodegradation is one of the most important directions for future polymer science. This article presents the main preparation methods for biodegradable polymers and discusses their degradation mechanisms, the biodegradable factors, recent researches and their applications. The future researches of biodegradable polymers are also put forward.

  2. Communicating in Polish.

    Science.gov (United States)

    Penny, Bernard; Malinowska, Krystyna T.

    This Polish textbook consists of a series of narrations and dialogs based on photographs depicting typical activities in the daily lives of Polish citizens. Two sets of questions follow each selection; the first set is intended to stimulate communication on what has been seen and heard, while the second set asks the students to compare what they…

  3. Micro-structural analysis of local damage introduced in subsurface regions of 4H-SiC wafers during chemo-mechanical polishing

    Science.gov (United States)

    Sako, Hideki; Matsuhata, Hirofumi; Sasaki, Masayuki; Nagaya, Masatake; Kido, Takanori; Kawata, Kenji; Kato, Tomohisa; Senzaki, Junji; Kitabatake, Makoto; Okumura, Hajime

    2016-04-01

    The surface morphology and lattice defect structures in the subsurface regions of 4H-SiC wafers introduced during chemo-mechanical polishing (CMP) were studied by scanning electron microscopy and transmission electron microscopy. It is known that local damage consisting of high-density lattice defects is introduced in the wafers during the current CMP, however, optical microscopy showed that the surface was very flat and clean without any presence of surface defects. Specifically, this study focused on the detailed analysis of such lattice defect structures. The high-density lattice defects locally introduced in the subsurface regions consisted of nano-scale surface scratches, high-density basal-plane dislocation loops, Shockley-type stacking faults, and Y-shaped defects. Two types of dislocation loops were introduced near the scratches that were selected for further study: nearly perfect basal-plane dislocations, which were accompanied by narrow stacking faults, and apparent partial basal-plane dislocations, which were accompanied by wide stacking faults. A Y-shaped defect was observed in the local damage along the [ 11 2 ¯ 0 ] direction, but not in the local damage along the [ 1 ¯100 ] direction. It was also found that the directions of the Burgers vectors for the basal-plane dislocations clearly depended on the directions of the introduced scratch-like defects.

  4. The Application of Bileaflet Mechanical Heart Valves in the Polish Ventricular Assist Device: Physical and Numerical Study and First Clinical Usage.

    Science.gov (United States)

    Malota, Zbigniew; Sadowski, Wojciech; Krzyskow, Marek; Stolarzewicz, Bogdan

    2016-03-01

    The Polish ventricular assist device (Polvad) has been used successfully in clinical contexts for many years. The device contains two single-disc valves, one at the inlet and one at the outlet connector of the pneumatic pump. Unfortunately, in recent years, a problem has occurred with the availability of single-disc valves. This article presents the possibility of using bileaflet mechanical heart valve prostheses in the Polvad to avoid a discontinuity in clinical use. The study is based on experimental and numerical simulations and comparison of the distribution of flow, pressure, and stress (wall, shear, and turbulent) inside the Polvad chamber and the inlet/outlet connectors fitted with Sorin Monodisc and Sorin Bicarbon Fitline valves. The type and orientation of the inlet valve affects valve performance and flow distribution inside the chamber. Near-wall flow is observed for single-disc valves. In the case of bileaflet valves, the main jet is directed more centrally, with lower shear stress but higher turbulent stress in comparison with single-disc valves. For clinical usage, a 45° orientation of the bileaflet inlet valve was chosen, as this achieves good washing of the inlet area near the membrane paste surface. The Polvad with bileaflet valves has now been used successfully in our clinic for over a year and will continue to be used until new assist devices for heart support are developed.

  5. 固结磨料化学机械研抛K9玻璃的材料去除机理%Material Removal Mechanism of K9 Glass During Chemical Mechanical Polishing by Fixed Abrasive Pad

    Institute of Scientific and Technical Information of China (English)

    樊吉龙; 朱永伟; 李军; 叶剑锋

    2012-01-01

    采用失重法对固结磨料研抛K9玻璃材料去除过程中的机械与化学作用进行了分离,采用显微硬度方法分析了研抛液对K9玻璃工件表层硬度的影响.研究结果表明:研抛液能与K9玻璃发生化学反应并在其表面形成一层较基质材料软的变质层,变质层厚度随浸泡时间的延长而增加;单纯研抛液的化学作用对K9玻璃的材料去除作用有限,固结磨料研抛垫对K9玻璃的机械去除作用主要以脆性去除为主,化学与机械的交互作用是K9玻璃影响材料去除的主要方式:当研抛盘转速为200r/min时,化学作用与机械作用达到平衡,交互作用最为强烈,材料去除率达到最大值.%The mechanical and chemical functions during the material removal process are separated by adopting weight loss measurements when fixed abrasive pad works on K9 glass. The influence of polishing slurry on the surface hardness of K9 glass is also analyzed by the micro-hardness method. The research results show that the chemical reaction between polishing slurry and K9 glass will take place and form a denatured layer on the surface of K9 glass, which is softer than host material and whose thickness increases with soak time. The material removal rate of K9 glass by chemical function is very limited and the mechanical function of K9 glass is mainly by brittle removal, while the interaction of chemical and mechanical functions is the main factor in influencing the material removal rate of K9 glass. When the rotation speed of the polishing pad is 200 r/min, the chemical and mechanical functions come to a balance with their interaction being the strongest, and the material removal rate reaches its maximum.

  6. Nano-scale stick-slip friction model for the chatter scratch generated by chemical mechanical polishing process.

    Science.gov (United States)

    Kim, Hong Jin; Yang, Ji Chul; Yoon, Bo Un; Lee, Hyeon-Deok; Kim, Taesung

    2012-07-01

    Although Chemical Mechanical Planarization (CMP) process is a still promising technology for the fabrication of the next generation devices, CMP-induced defects tackle further development of CMP process. In particular, even nano-sized scratches generated by CMP process kill the device directly. However mechanism of scratch formation was not clearly understood yet. CMP-induced scratches are classified as razor, chatter mark and skipping scratch. Among them, chatter mark scratch (or chatter scratch) is the most critical defect for the device yield loss. Chatter scratch has a periodic pattern of scars, which is reminiscent of a stick-slip friction pattern. Based on that similarity, stick-slip model was proposed in this paper in order to explain how chatter scratch is formed. And controlling parameters for chatter scratch are defined. During stick period the friction force that exceeds the yield strength of wafer surface makes chatter scratch and the distance between chatter marks is determined by slip period.

  7. Hydroxyapatite nanocrystals: Simple preparation, characterization and formation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Mohandes, Fatemeh [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P. O. Box. 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P. O. Box. 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P. O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Fathi, Mohammadhossein [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111, Islamic Republic of Iran (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan, Islamic Republic of Iran (Iran, Islamic Republic of); Fereshteh, Zeinab [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111, Islamic Republic of Iran (Iran, Islamic Republic of)

    2014-12-01

    Crystalline hydroxyapatite (HAP) nanoparticles and nanorods have been successfully synthesized via a simple precipitation method. To control the shape and particle size of HAP nanocrystals, coordination ligands derived from 2-hydroxy-1-naphthaldehyde were first prepared, characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance ({sup 1}H-NMR) spectroscopies, and finally applied in the synthesis process of HAP. On the other hand, the HAP nanocrystals were also characterized by several techniques including powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). According to the FE-SEM and TEM micrographs, it was found that the morphology and crystallinity of the HAP powders depended on the coordination mode of the ligands. - Highlights: • HAP nanobundles and nanoparticles have been prepared by a precipitation method. • Morphologies of HAP nanocrystals were controlled by different coordination ligands. • The formation mechanism of hydroxyapatite nanocrystals was also considered.

  8. 单晶金刚石机械研磨与化学机械抛光工艺%Mechanical Lapping and Chemical-Mechanical Polishing Process for Single Crystal Diamond

    Institute of Scientific and Technical Information of China (English)

    薛洪明; 金洙吉; 史卓颖

    2015-01-01

    单晶金刚石在工业、国防等领域的应用日益广泛,对其加工表面质量的要求不断提高,使用常温低压的化学机械抛光可实现金刚石的超光滑低损伤表面加工。通过理论分析及实验研究得出,使用硅酸盐玻璃材质研磨盘进行研磨加工,可以将金刚石表面粗糙度Ra降至15~25 nm,且无明显机械划痕;在2 MPa压力及室温环境下进行单晶金刚石化学机械抛光实验,优选出Fenton试剂酸性水基抛光液,使用该抛光液抛光单晶金刚石可获得粗糙度Ra值4 nm以下的光滑表面。%Single crystal diamond is more and more widely used in national defense and industrial field , which requires better surface quality .The technique of chemical-mechanical polishing at normal-tempera-ture and low-pressure environment can achieve ultra-smooth diamond surface with low damage .Theoreti-cal analysis and experimental research show that the polished diamond surface roughness Ra can be re-duced to 15—25 nm without obvious mechanical scratches by using silicate glass as grinding disc .The chemical-mechanical polishing experiment was held under the condition of 2 MPa pressure and normal-temperature .Experimental results show that the water-based acidic Fenton reagent was effective in parti-cular process parameters , and overall surface roughness Ra was processed to be less than 4 nm.

  9. Effects of polishing procedures on color stability of composite resins

    Directory of Open Access Journals (Sweden)

    Ahmet Umut Güler

    2009-04-01

    Full Text Available The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme. Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd, polishing discs then diamond polishing paste (PdP, polishing discs then a liquid polishing system (Biscover (PdB, and combinations of these (PdPB were used. Unpolished specimens served as the control (C. The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DE* were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (a=0.05. The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme. The posterior (Filtek P60 and universal (Filtek Z250 composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA, were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme and universal (Quadrant LC composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the Biscover liquid polish

  10. CHINESE RE POLISHING POWDER INDUSTRY

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Due to its high polishing efficiency, long working life and wide application range, RE polishing powder has become the most popular fine polishing material. In recent years, accompanying the rapid development of electronic information technology, the demand for polishing powder is

  11. Study of impurity distribution in mechanically polished, chemically treated and ultra-high vacuum degassed pure Niobium samples using TOFSIMS technique

    CERN Document Server

    Bose, A

    2015-01-01

    The performance of Superconducting radio frequency cavities (SCRF) are highly dependent on the surface treatment processes, which in turn is influenced by the chemistry within the penetration depth of Niobium (Nb). The present study analyses various impurities within the RF penetration depth (~50nm) of Nb samples treated by SCRF cavity processing techniques like colloidal silica polishing (simulating centrifugal barrel polishing), buffer chemical polishing (BCP), high pressure rinsing (HPR) and degassing under ultra high vacuum (UHV) condition at 600{\\deg}C for 10hrs. Various modes of Time of flight secondary ion mass spectrometry (TOFSIMS) technique was employed to study the effect of the above treatments on the vast spectrum of impurities that include interstitials, hydrocarbons, oxides, acidic residuals, reaction products and metallic impurities. UHV degassing treatment was the only treatment capable of reducing hydrogen contamination, but, it led to extensive oxygen, carbon and metallic impurities in the ...

  12. Elastic emission polishing

    Energy Technology Data Exchange (ETDEWEB)

    Loewenthal, M.; Loseke, K.; Dow, T.A.; Scattergood, R.O.

    1988-12-01

    Elastic emission polishing, also called elastic emission machining (EEM), is a process where a stream of abrasive slurry is used to remove material from a substrate and produce damage free surfaces with controlled surface form. It is a noncontacting method utilizing a thick elasto-hydrodynamic film formed between a soft rotating ball and the workpiece to control the flow of the abrasive. An apparatus was built in the Center, which consists of a stationary spindle, a two-axis table for the workpiece, and a pump to circulate the working fluid. The process is controlled by a programmable computer numerical controller (CNC), which presently can operate the spindle speed and movement of the workpiece in one axis only. This apparatus has been used to determine material removal rates on different material samples as a function of time, utilizing zirconium oxide (ZrO{sub 2}) particles suspended in distilled water as the working fluid. By continuing a study of removal rates the process should become predictable, and thus create a new, effective, yet simple tool for ultra-precision mechanical machining of surfaces.

  13. [The role of Wacława Moszyński in the development of the Polish School of Machine and Mechanism Theory].

    Science.gov (United States)

    Kisiel, Janusz; Pylak, Konrad; Schabowska, Krystyna

    2005-01-01

    The end of the 19th and the first half of the 20th centuries saw the emergence and intensive development of many disciplines in the technical sciences, and the laying of a groundwork for those disciplines in their current form. In Poland, a country deprived of independent statehood until 1918, this was additionally a period when native research centres and scientific schools came into being, and when Polish-language specialist literatures emerged as well. Many of the eminent personages whose activities contributed to those trends have already been described in biographical notes and articles. There are still, however, not enough studies dealing with the substance of their scientific and professional achievements. One of the personages in question was Wacława Moszyński, professor of the Warsaw Technical University, a pioneer of machine construction and mechanism theory, author of the first academic textbook in the field to be published in Poland. The current article discusses Moszyński's contribution to the development of mechanism and machine theory. The first part of the article gives an outline of the history of the discipline until 1945, presents the context of the after-war activities of the author, and evaluates his influence on the development of machine and mechanism theory in Poland; it also carries a short biography of Moszyński. The rest of the article is devoted to Moszyński's scientific achievements, and describes his approach to matters of structure, kinematics and dynamics, with special focus on those of his formulations and solution to problems that appear particularly innovative and original. The article also points out those proposals by Moszyński which made him a precursor of other disciplines, such as vibroacoustics, biomechanics and ergonomics. The paper also presents the role of Moszyński's work as a foundation for the development of the Warsaw research-and-teching centre in the field. The achievements and methods of the Warsaw school

  14. Processing, Mechanical and Optical Properties of Additive-Free ZrC Ceramics Prepared by Spark Plasma Sintering

    Directory of Open Access Journals (Sweden)

    Clara Musa

    2016-06-01

    Full Text Available In the present study, nearly fully dense monolithic ZrC samples are produced and broadly characterized from microstructural, mechanical and optical points of view. Specifically, 98% dense products are obtained by Spark Plasma Sintering (SPS after 20 min dwell time at 1850 °C starting from powders preliminarily prepared by Self-propagating High-temperature Synthesis (SHS followed by 20 min ball milling. A prolonged mechanical treatment up to 2 h of SHS powders does not lead to appreciable benefits. Vickers hardness of the resulting samples (17.5 ± 0.4 GPa is reasonably good for monolithic ceramics, but the mechanical strength (about 250 MPa up to 1000 °C could be further improved by suitable optimization of the starting powder characteristics. The very smoothly polished ZrC specimen subjected to optical measurements displays high absorption in the visible-near infrared region and low thermal emittance at longer wavelengths. Moreover, the sample exhibits goodspectral selectivity (2.1–2.4 in the 1000–1400 K temperature range. These preliminary results suggest that ZrC ceramics produced through the two-step SHS/SPS processing route can be considered as attractive reference materials for the development of innovative solar energy absorbers.

  15. The technology and mechanism of removal of plastic mulch and land preparation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Huiyou; HOU Shulin; NA Mingjun; YANG Xiaoli; BAI Shengnan

    2007-01-01

    In this article ,the characteristic of the field plastic mulch, the craft for mechanization removal and land preparation of plastic mulch and the mechanism frequently used in the removal and land preparation of plastic mulch were introduced, which offered references for the design of removal mechanism and land preparation of plastic mulch and structural optimization combination of working components.

  16. Enhancement of high-TC superconducting thin film devices by nanoscale polishing

    Science.gov (United States)

    Michalowski, P.; Shapoval, T.; Meier, D.; Katzer, C.; Schmidl, F.; Schultz, L.; Seidel, P.

    2012-11-01

    The effects of mechanical nanoscale polishing on the superconducting parameters of YBa2Cu3O7-δ (YBCO) thin films and bi-crystal grain boundary Josephson junctions have been investigated. We prepared samples with additional gold nanocrystallites in the YBCO film. As they are distributed throughout the whole YBCO film, they provide a low-resistance ohmic contact even if parts of the film are removed. Polishing was performed either before or after the patterning and did not change the properties of the grain boundary. However, nanopolishing reduces the film roughness in a significant way, which makes it an indispensable tool for the preparation of integrated superconducting circuits. We also succeeded in tuning the IC and RN of the Josephson junctions of direct current superconducting quantum interference devices (dc-SQUIDs) by systematically reducing the film thickness, which opens up new possibilities in the application of magnetic field sensors.

  17. Functional Median Polish

    KAUST Repository

    Sun, Ying

    2012-08-03

    This article proposes functional median polish, an extension of univariate median polish, for one-way and two-way functional analysis of variance (ANOVA). The functional median polish estimates the functional grand effect and functional main factor effects based on functional medians in an additive functional ANOVA model assuming no interaction among factors. A functional rank test is used to assess whether the functional main factor effects are significant. The robustness of the functional median polish is demonstrated by comparing its performance with the traditional functional ANOVA fitted by means under different outlier models in simulation studies. The functional median polish is illustrated on various applications in climate science, including one-way and two-way ANOVA when functional data are either curves or images. Specifically, Canadian temperature data, U. S. precipitation observations and outputs of global and regional climate models are considered, which can facilitate the research on the close link between local climate and the occurrence or severity of some diseases and other threats to human health. © 2012 International Biometric Society.

  18. Fabrication and Characterization of FeNiCr Matrix-TiC Composite for Polishing CVD Diamond Film

    Institute of Scientific and Technical Information of China (English)

    Zhuji Jin; Zewei Yuan; Renke Kang; Boxian Dong

    2009-01-01

    Dynamic friction polishing (DFP) is one of the most promising methods appropriate for polishing CVD diamond film with high efficiency and low cost.By this method CVD diamond film is polished through being simply pressed against a metal disc rotating at a high speed utilizing the thermochemical reaction occurring as a result of dynamic friction between them in the atmosphere.However, the relatively soft materials such as stainless steel, cast iron and nickel alloy widely used for polishing CVD diamond film are easy to wear and adhere to diamond film surface, which may further lead to low efficiency and poor polishing quality.In this paper, FeNiCr matrix-TiC composite used as grinding wheel for polishing CVD diamond film was obtained by combination of mechanical alloying (MA) and spark plasma sintering (SPS).The process of ball milling,composition, density, hardness, high-temperature oxidation resistance and wear resistance of the sintered piece were analyzed.The results show that TiC was introduced in MA-SPS process and had good combination with FeNiCr matrix and even distribution in the matrix.The density of composite can be improved by mechanical alloying.The FeNiCr matrix-TiC composite obtained at 1273 K was found to be superior to at 1173 K sintering in hardness, high-temperature oxidation resistance and wearability.These properties are more favorable than SUS304 for the preparation of high-performance grinding wheel for polishing CVD diamond film.

  19. Preparation and mechanical properties of graphene oxide: cement nanocomposites.

    Science.gov (United States)

    Babak, Fakhim; Abolfazl, Hassani; Alimorad, Rashidi; Parviz, Ghodousi

    2014-01-01

    We investigate the performance of graphene oxide (GO) in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1-2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found that the tensile strength of the cement mortar increased with GO content, reaching 1.5%, a 48% increase in tensile strength. Ultra high-resolution field emission scanning electron microscopy (FE-SEM) used to observe the fracture surface of samples containing 1.5 wt% GO indicated that the nano-GO flakes were well dispersed in the matrix, and no aggregates were observed. FE-SEM observation also revealed good bonding between the GO surfaces and the surrounding cement matrix. In addition, XRD diffraction data showed growth of the calcium silicate hydrates (C-S-H) gels in GO cement mortar compared with the normal cement mortar.

  20. Performance analysis of CO2 laser polished angled ribbon fiber

    Science.gov (United States)

    Sohn, Ik-Bu; Choi, Hun-Kook; Noh, Young-Chul; Lee, Man-Seop; Oh, Jin-Kyoung; Kim, Seong-min; Ahsan, Md. Shamim

    2017-01-01

    This paper demonstrates CO2 laser assisted simultaneous polishing of angled ribbon fibers consisting eight set of optical fibers. The ribbon fibers were rotated vertically at an angle of 12° and polished by repetitive irradiation of CO2 laser beam at the end faces of the fibers. Compared to mechanically polished sharp edged angled fibers, CO2 laser polishing forms curve edged angled fibers. Increase in the curvature of the end faces of the ribbon fibers causes the increase of the fibers' strength, which in turn represents great robustness against fiber connections with other devices. The CO2 laser polished angled fibers have great smoothness throughout the polished area. The smoothness of the fiber end faces have been controlled by varying the number of laser irradiation. After CO2 laser polishing, the average value of the fiber angle of the ribbon fibers is ∼8.28°. The laser polished ribbon fibers show low insertion and return losses when connecting with commercial optical communication devices. The proposed technique of polishing the angled ribbon fibers is highly replicable and reliable and thus suitable for commercial applications.

  1. Temporal Expressions in Polish Corpus KPWr

    Directory of Open Access Journals (Sweden)

    Jan Kocoń

    2015-12-01

    Full Text Available Temporal Expressions in Polish Corpus KPWr This article presents the result of the recent research in the interpretation of Polish expressions that refer to time. These expressions are the source of information when something happens, how often something occurs or how long something lasts. Temporal information, which can be extracted from text automatically, plays significant role in many information extraction systems, such as question answering, discourse analysis, event recognition and many more. We prepared PLIMEX — a broad description of Polish temporal expressions with annotation guidelines, based on the state-of-the-art solutions for English, mainly TimeML specification. We also adapted the solution to capture the local semantics of temporal expressions, called LTIMEX. Temporal description also supports further event identification and extends event description model, focusing at anchoring events in time, ordering events and reasoning about the persistence of events. We prepared the specification, which is designed to address these issues and we annotated all documents in Polish Corpus of Wroclaw University of Technology (KPWr using our annotation guidelines.

  2. Buffered Electrochemical Polishing of Niobium

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tian, Hui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States); Corcoran, Sean [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2011-03-01

    The standard preparation of superconducting radio-frequency (SRF) cavities made of pure niobium include the removal of a 'damaged' surface layer, by buffered chemical polishing (BCP) or electropolishing (EP), after the cavities are formed. The performance of the cavities is characterized by a sharp degradation of the quality factor when the surface magnetic field exceeds about 90 mT, a phenomenon referred to as 'Q-drop.' In cavities made of polycrystalline fine grain (ASTM 5) niobium, the Q-drop can be significantly reduced by a low-temperature (? 120 °C) 'in-situ' baking of the cavity if the chemical treatment was EP rather than BCP. As part of the effort to understand this phenomenon, we investigated the effect of introducing a polarization potential during buffered chemical polishing, creating a process which is between the standard BCP and EP. While preliminary results on the application of this process to Nb cavities have been previously reported, in this contribution we focus on the characterization of this novel electrochemical process by measuring polarization curves, etching rates, surface finish, electrochemical impedance and the effects of temperature and electrolyte composition. In particular, it is shown that the anodic potential of Nb during BCP reduces the etching rate and improves the surface finish.

  3. Centrifugal barrel polishing of 1.3 GHz Nb cavities

    Energy Technology Data Exchange (ETDEWEB)

    Tamashevich, Yegor; Foster, Brian [DESY, Hamburg (Germany); Hamburg Univ. (Germany); Navitski, Aliaksandr; Steder, Lea; Elsen, Eckhard [DESY, Hamburg (Germany)

    2013-07-01

    Superconducting radio-frequency (SRF) cavities are the key components of particle accelerators such as the European X-ray Free Electron Laser (XFEL, under construction) and the planned future International Linear Collider (ILC). Steady progress in surface treatment techniques of SRF cavities in both the achievable quality factor Q and the accelerating electric field Eacc makes new accelerators and ambitious projects feasible. One of the alternative surface preparation techniques which is actually being explored is centrifugal barrel polishing (CBP) pioneered at KEK in Japan in mid-nineties by T. Hiuchi et al. CBP is a mechanical polishing of cavities and results in around 10 x smaller surface roughness and mirror-like surface as compared to chemistry alone. Q and E{sub acc} are expected to be at least as high as for chemically treated cavities. CBP eliminates the bulk chemistry and has the potential to completely replace the chemistry. The University of Hamburg is installing a CBP machine to study it as a cavity preparation and repair technique for 9-cell 1.3 GHz SRF cavities at the Deutsche Elektronen-Synchrotron (DESY). The setup and first commissioning tests will be presented and discussed.

  4. Preparation for Low Surface Energy/Self-Polishing Silicone Marine Antifouling Coating%有机硅低表面能/自抛光海洋防污涂料的制备

    Institute of Scientific and Technical Information of China (English)

    陈美玲; 冯树涛; 张羽生; 杨莉; 高宏

    2013-01-01

    To prepare the title self-polishing antifouling coatings,a graft copolymerization method was proposed.Through the reaction of epoxy and acrylic acid,an acrylic monomer with hydroxyl groups was prepared,which was then,together with two other acrylic monomer and initiator,grafted with silicone at the preseuce of catalyst to form the silicone epoxy acrylate resin.The effects of epoxy dosage on coating performance and the hydrolysis characteristic of the film was discussed.Sample panels were tested in the real marine water.The results showed that 10% of the epoxy gave the best hydrolysis characteristics in laboratory dynamic simulation experiments with water contactangle 133° and adhesion grade 1.In the meantime,the low surface energy and self-polishing silicone antifouling coatings also provided good antifouling performance in static sea water immersion.%采用接枝共聚的方法,即环氧和丙烯酸反应,环氧开环的同时生成带有羟基的丙烯酸单体,加入引发剂结合另外2种丙烯酸单体,在催化剂的作用下接入有机硅,制得有机硅环氧丙烯酸树脂.讨论了环氧树脂的用量对涂膜性能的影响、涂料的水解特性,并进行了实海挂板实验.结果表明:当环氧的用量为10%时,制备的防污涂料与水的接触角达到133°,附着力1级;有机硅/环氧改性丙烯酸树脂制得的防污涂料在海水中能够稳定地水解,兼具低表面能和自抛光的特性,实海挂板实验结果表明,涂料具有良好的防污性能.

  5. Preparation of Associative Polyurethane Thickener and Its Thickening Mechanism Research

    Directory of Open Access Journals (Sweden)

    Gao Nan

    2015-01-01

    Full Text Available Associative polyurethane (PU thickener has been synthesized by preparing the prepolymer with the reaction of polyethylene glycol (PEG and isophorone diisocyanate (IPDI, which then end-capping with long-chain alkanol. The synthesis process, as well as hydrophilic chain length, theoretical molecular weight, solvent ratio, and thickener percentages, has been researched. The results shows that it reaches the upmost thickening effect when the theoretical molecular weight is under 20000, soft-segment length is under 4000, solvent ratio is 1 : 1, and thickener percentages are controlled at 10%. Furthermore, thickening mechanism of PU thickener has been analyzed detailedly through the measurement of the critical micelle concentration (CMC of PU thickener and analysis of the influence of PU thickener on the particle size and morphology of PU dispersions. It has been observed from the scanning electron microscopy (SEM that the PU aqueous dispersions produce a certain degree of flocculation when the PU thickener was added, and this flocculation structure has been proved to be a thixotropic structure through the characterization of the change of particle size before and after the thickener is introduced into the PU aqueous dispersions. The CMC measurement results present that the thickening effect will be apparent when the concentration is controlled in a low range.

  6. Solid state amorphisation in binary systems prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, G., E-mail: gemagonz@ivic.v [Lab. Ciencia e Ing. de Materiales, Instituto Venezolano de Investigaciones Cientificas, IVIC, Caracas (Venezuela, Bolivarian Republic of); Sagarzazu, A. [Lab. Ciencia e Ing. de Materiales, Instituto Venezolano de Investigaciones Cientificas, IVIC, Caracas (Venezuela, Bolivarian Republic of); Bonyuet, D. [Instituto de Investigacion en Biomedicina y Ciencias Aplicadas, Universidad de Oriente, Cumana (Venezuela, Bolivarian Republic of); D' Angelo, L. [UNEXPO, Universidad Experimental Politecnica Luis Caballero Mejias, Dpto. Ing. Mecanica (Venezuela, Bolivarian Republic of); Villalba, R. [Lab. Ciencia e Ing. de Materiales, Instituto Venezolano de Investigaciones Cientificas, IVIC, Caracas (Venezuela, Bolivarian Republic of)

    2009-08-26

    In the present work a detailed study of amorphisation in different systems prepared by mechanical alloying under the same experimental conditions was carried out, milling up to 50 and 100 h in some cases. The systems studied were: AlTi, AlNi, AlFe, FeNi, FeCo, NiMo, NiW, NiCo, MoW, CoMo. These systems were chosen to study the effect of Al-transition metal, transition metal-transition metal and also systems with large and small negative heat of mixing, different and similar crystal structures, atomic sizes and diffusion coefficients. Calculations based on the Miedema model for alloy formation and amorphisation on all the alloys studied were performed. The experimental results from X-ray diffraction and transmission electron microscopy showed that the systems based on Fe (FeNi, FeCo and FeAl) did not amorphised, even after milling for 100 h, and formed a stable solid solution with a nanometric grain size of 7 nm. The systems NiMo, NiW, MoW and CoMo (systems with small negative heat of mixing), showed amorphisation after 50 h of milling. NiAl and TiAl form an intermediate amorphous phase after around 20 h of milling and with further milling they recrystallize into a fcc solid solution. Agreement between the theoretical calculations based on the Miedema model and the experimental results was found in most of the systems.

  7. Nasalization in Polish

    Science.gov (United States)

    Rubach, Jerzy

    1977-01-01

    This paper gives a complete account of vowel nasalization in Standard Polish. A distinction is made between obligatory and phonostylistic processes. Phonostylistic evidence may serve as a basis for making unambiguous decisions about the structure of underlying representations, intermediate phonological forms, and assimilation of borrowings to the…

  8. Fluid Jet Polishing

    NARCIS (Netherlands)

    Booij, S.M.

    2003-01-01

    The goal of this thesis research was to investigate the possibilities and limitations of the Fluid Jet Polishing (FJP) technique. FJP is a new optical fabrication technique that is capable of making shape corrections and reducing the surface roughness of glass and other materials. The principle of o

  9. Aspectual Pairing in Polish

    NARCIS (Netherlands)

    Młynarczyk, A.K.

    2004-01-01

    The received view on Slavic aspect is that it is intrinsically complex, and that there is little hope of discerning any substantial regularity. We argue that this view is mistaken. We argue that the vast majority of Polish verbs really do come in aspectual pairs and that far from being a mysterious

  10. Fluid Jet Polishing

    NARCIS (Netherlands)

    Booij, S.M.

    2003-01-01

    The goal of this thesis research was to investigate the possibilities and limitations of the Fluid Jet Polishing (FJP) technique. FJP is a new optical fabrication technique that is capable of making shape corrections and reducing the surface roughness of glass and other materials. The principle of

  11. Sexual activity of Polish adults

    Directory of Open Access Journals (Sweden)

    Beata Pastwa-Wojciechowska

    2014-03-01

    Full Text Available Aim. The purpose of this research was to explore the subject of sexual activity in the Polish population, with special focus on age and gender differences, and sexual infidelity. Sexual activity is one of the basic factors in initiating and maintaining relationships. On the one hand, sexual activity enables us to meet natural needs and maintain an intimate relationship with another human being; on the other, it may allow us to overcome loneliness and social isolation by providing the opportunity to express feelings of closeness and unity. Material and method. The research was conducted on a representative group of 3,200 Poles aged between 15–49, with the support of a well-known Polish research company – TNS OBOP. Face-to-face and Pencil and Paper (PAPI interviews were carried out. Results. The results focus on two main issues: the age and motives of sexual initiation among teenagers (with a significant percentage starting their sexual activity at the age of 15, and the quality of the sexual lives of adults (average number of sexual partners, sexual infidelity and sexual satisfaction. Conclusion. There is dependence between the type of relationship and the performance or non-performance of sexual activity, as well as the quality of the relationship. Among both adolescents and adults, remaining in a stable relationship (partnership or marriage promotes loyalty. The performance of sexual goals turns out to be an important mechanism regulating the interpersonal aspects of a relationship, influencing their perception and evaluation.

  12. Ultrasmooth surface polishing based on the hydrodynamic effect.

    Science.gov (United States)

    Peng, Wenqiang; Guan, Chaoliang; Li, Shengyi

    2013-09-01

    This study will examine the feasibility of applying the hydrodynamic effect to ultrasmooth surface polishing. Differing from conventional pad polishing, hydrodynamic effect polishing is noncontact, as the polishing wheel is floated on the workpiece under the hydrodynamic effect. The material removal mechanism and the removal contour are analyzed in detail. Dynamic pressure and shear stress distribution on the workpiece are numerically simulated in three dimensions under different clearances between the polishing wheel and the workpiece, showing that the dynamic pressure distribution and the magnitude of shear stress on the workpiece are greatly influenced by the clearance. It is clearly demonstrated from fixed-point polishing experiments that material removal rates and contours are determined by the combined action of dynamic pressure and shear stress. A material removal analytic model is presented with the hydrodynamic effect polishing method. Finally, a polishing experiment is conducted on a quartz glass and the plastic scratches, cracks, and bumpy structures on the initial surface are clearly removed. Moreover, the processed surface roughness is improved to 0.145 nm rms, 0.116 nm Ra.

  13. Surface roughness of a novel dental porcelain following different polishing procedures.

    Science.gov (United States)

    Wang, Fu; Chen, Ji-Hua; Wang, Hui

    2009-01-01

    This study aimed to compare the surface roughness of a novel dental porcelain following different polishing procedures. One hundred twenty Imagine Reflex porcelain disks were prepared and randomly assigned into six groups according to different treatments: Group 1: CeraMaster polishing system (CP); Group 2: CP + diamond polishing paste (DP); Group 3: Sof-Lex polishing system (SS); Group 4: SS + DP; Group 5: SiC paper polishing; Group 6: reglazing (control). After the respective treatments, surface roughness values were measured using a profilometer. Qualitative analysis was performed using scanning electron microscopy. Results demonstrated that a combination of the CeraMaster polishing system and a diamond polishing paste could produce similar superficial smoothness to that of the reglazed surface of the tested porcelain.

  14. Review of research literature on: "Parenting styles and childrearing practices among Poles : historical and contemporary perspectives" : report prepared in the framework of the Polish-Norwegian research project PARMigration Navigator

    OpenAIRE

    2015-01-01

    This report summarizes the findings of a literature review of existing research on issues pertaining to parenting styles and child rearing practices among Polish migrant families living abroad in different immigration contexts and under changing socio-economic conditions in Poland. The review was conducted in the scope of the international research project entitled ‘Socio-cultural and Psychological Predictors of Work-Life Balance and Gender Equality - Cross-Cultural Comparison of Polish a...

  15. Effect of different polishing systems on the surface roughness of microhybrid composites

    Directory of Open Access Journals (Sweden)

    Kristine Guará Brusaca Almeida Scheibe

    2009-02-01

    Full Text Available The use of composite resins in dentistry is well accepted for restoring anterior and posterior teeth. Many polishing protocols have been evaluated for their effect on the surface roughness of restorative materials. This study compared the effect of different polishing systems on the surface roughness of microhybrid composites. Thirty-six specimens were prepared for each composite $#91;Charisma® (Heraeus Kulzer, Fill Magic® (Vigodent, TPH Spectrum® (Dentsply, Z100® (3M/ESPE and Z250® (3M/ESPE] and submitted to surface treatment with Enhance® and PoGo® (Dentsply points, sequential Sof-Lex XT® aluminum oxide disks (3M/ESPE, and felt disks (TDV combined with Excel® diamond polishing paste (TDV. Average surface roughness (Ra was measured with a mechanical roughness tester. The data were analyzed by two-way ANOVA with repetition of the factorial design and the Tukey-Kramer test (p<0.01. The F-test result for treatments and resins was high (p<0.0001 for both, indicating that the effect of the treatment applied to the specimen surface and the effect of the type of resin on surface roughness was highly significant. Regarding the interaction between polishing system and type of resin used, a p value of 0.0002 was obtained, indicating a statistically significant difference. A Ra of 1.3663 was obtained for the Sof-Lex/TPH Spectrum interaction. In contrast, the Ra for the felt disk+paste/Z250 interactions was 0.1846. In conclusion, Sof-Lex polishing system produced a higher surface roughness on TPH Spectrum resin when compared to the other interactions.

  16. Factors influencing the surface quality of polished tool steels

    Science.gov (United States)

    Rebeggiani, S.; Rosén, B.-G.

    2014-09-01

    Today’s demands on surface quality of moulds for injection moulding of plastic components involve no/low defect contents and roughness levels in the nm-range for high gloss applications. Material properties as well as operating conditions influence the mould finish, and thus the final surface of moulded products. This paper focuses on how particle content and different polishing strategies influence final surface qualities of moulds. Visual estimations of polished tool steel samples were combined with non-contact 3D-surface texture analysis in order to correlate traditional assessments to more quantitative methods, and to be able to analyse the surfaces at nanometre-level. It was found that steels with a lower proportion of particles, like carbides and oxides, gave rise to smoother polished surfaces. In a comparative study of polishers from different polishing shops, it was found that while different surface preparation strategies can lead to similar final roughness, similar preparation techniques can produce high-quality surfaces from different steel grades. However, the non-contact 3D-surface texture analysis showed that not all smooth polished surfaces have desirable functional topographies for injection moulding of glossy plastic components.

  17. Tetragonal zirconia: Wet chemical preparation, mechanical and electrical properties

    NARCIS (Netherlands)

    Keizer, K.; Hemert, van M.; Graaf, van de M.A.C.G.; Burggraaf, A.J.

    1985-01-01

    Yttria-stabilized zirconia powders were prepared in the composition range of 3 to 13 at% yttria. The hydrolysis-gel precipitation technique was used, starting from metal alkoxides or chlorides. In the composition range between 5 and 10 at% yttria, the materials sintered at 1250°C have a fully tetrag

  18. Ceramic Polishing Slag as Foaming Material for Preparation of Light Glazed Tile%以陶瓷抛光废渣为发泡原料制备轻质釉面砖的研究

    Institute of Scientific and Technical Information of China (English)

    许林峰; 曾德朝; 钟保民

    2016-01-01

    A light ceramic tile body with outstanding non-deformability was produced by using ceramic polishing slag as foaming material and clay,silica sand,potash feldspar as raw materials.And a high temperature glaze and a low tempera-ture glaze with coefficient of thermal expansion adapting to the body were also produced.Light ceramic glazed tiles with ex-cellentglaze surface were prepared by a method of double-layer glazing.The test results indicate that the light ceramic glazed tiles show excellentantifouling property,and the flexural strength of 8.47 MPa and heat conductivity coefficient of 0. 39 W/m·K were reached.%以抛光废渣为发泡原料,结合粘土、石英、钾长石等陶瓷原料,制备出抗变形能力好的轻质陶瓷砖坯;并研制出热膨胀系数与轻质砖坯适配的高温釉料和低温釉料;采用双层布釉的方法,制备出釉面质量良好的轻质釉面砖。测试结果表明:轻质陶瓷砖釉面具有优异的防污性能,抗折强度达到8.47 MPa,导热系数为0.39 W/m·K。

  19. Hydraulic supports for polishing TMT M3MP

    Science.gov (United States)

    Hu, Haifei; Qi, Erhui; Cole, Glen; Hu, Haixiang; Luo, Xiao; Ford, Virginia; Zhang, Xuejun

    2016-10-01

    For polishing the ultra-thin TMT M3MP, a polishing support system with 18 hydraulic supports (HS) is introduced. This work focuses on the designing and testing of these HSs. Firstly the design concept of HS system is discussed; then mechanical implementation of the HS structure is carried out, with special consideration of fluid cycling, work pressurization and the weight component. Afterward the piping installation and the de-gas process for the working fluid are implemented. Pressurization and stiffness are well checked before system integration for the single HS unit. Finally the support system is integrated for the polishing process.

  20. Contrastive Analysis of Metatext. Expressing Polish "niemniej" in Bulgarian

    Directory of Open Access Journals (Sweden)

    Anna Katarzyna Kisiel

    2015-12-01

    Full Text Available Contrastive Analysis of Metatext. Expressing Polish niemniej in Bulgarian The author discusses possible ways of expressing meanings of Polish niemniej, tym niemniej and niemniej jednak in Bulgarian. A confrontative analysis of the equivalents gives grounds for a reflection on how to conduct a cross-linguistic examination of metatext. Two important questions are raised: whether it is methodologically justified to compare objects non-identical such as units and compositions, lexical and grammatical means, and what exactly equivalence within metatext class means. It is expected that analysis of metatext in Polish and Bulgarian will allow to discover mechanisms of creating metatextual units.

  1. The Polish Cyborg. A Reflection on the Relationship between Man and Machine in Early Polish Modernism

    Directory of Open Access Journals (Sweden)

    Emiliano Ranocchi

    2016-12-01

    Full Text Available Far from being enthusiastic “modernolatry” of Italian futurism, Polish futurism demonstrates an attitude of ambivalence toward modernity. This is particularly evident in the Polish approach to that very synecdoche of modernity which is the machine. In his essay of 1923, the leader of the group, Bruno Jasieński, compares the fetishistic cult of the machine, which characterizes the Italian approach, with the utilitarian one of the Russians, exemplified by a quote from Majakovskij. To these two propositions, as a sort of Hegelian synthesis, he adds a Polish one consisting in the conception of the machine as a prosthesis, a continuation of the human body. Thereby he introduces an idea later known as “cyborg”. The category of cyborg is also useful to understand the work of another today almost forgotten Polish writer of the Twenties, Jerzy Sosnkowski. He was the author of a short novel, A Car, You and Me (Love of Machines, in which a whole chapter concerns the chief character’s dystopian nightmare wherein machines take control over the world. The third section of the essay deals with the idea of man a machine – an old, 18th century conception, which became actual anew in the 20th century and whose traces we can find among others in a well-known poem by Tytus Czyżewski. Thirty years before N. Wiener, Polish modernists seem to have sensed the social, political and anthropological implications of the mechanization of work.

  2. SPECTRAL METHODS IN POLISH EMOTIONAL SPEECH RECOGNITION

    Directory of Open Access Journals (Sweden)

    Paweł Powroźnik

    2016-12-01

    Full Text Available In this article the issue of emotion recognition based on Polish emotional speech signal analysis was presented. The Polish database of emotional speech, prepared and shared by the Medical Electronics Division of the Lodz University of Technology, has been used for research. Speech signal has been processed by Artificial Neural Networks (ANN. The inputs for ANN were information obtained from signal spectrogram. Researches were conducted for three different spectrogram divisions. The ANN consists of four layers but the number of neurons in each layer depends of spectrogram division. Conducted researches focused on six emotional states: a neutral state, sadness, joy, anger, fear and boredom. The averange effectiveness of emotions recognition was about 80%.

  3. EFFECTS OF POLISHING TIME AND THERMALCYCLINGON THE MICROLEAKAGE OF FOUR TOOTH –COLOURED DIRECT RESTORATIVE MATERIALS

    Directory of Open Access Journals (Sweden)

    V MORTAZAVI

    2002-09-01

    Full Text Available Introdaction. Microleakage has been recognized as a major clinical problem with direct filled dental restorations.The purpose of this study was to investigate and to compare the microleakage of four direct filled tooth-coloured materials, evaluation the effects of polishing time and thermocycling on the microleakage of these materials. Methods. Wedge-shaped class V cavities were prepared on buccal and lingual surfaces of 96 intact extracted human molar teeth. The teeth were randomly divided into three treatment groups and four subgroups. The cavities of each subgroup were filled using one of these materials: a conventional glass ionomer; a resin modified glass ionomer; a composite resin and a compomer. Polishing in the teeth of group 1 was done immediately after placement of restorations and in group 2 one week later. In group 3 delayed polishing and thermocycling (X100 was done. All of the teeth were stored in distilled water for one week and then stained with dye, sectioned, and scored for microleakage on occlusal and cervical edges. Results were statistically analyzed by Kruskal wallis and Mann whitney tests. Results. There was a statistically difference between the microleakage scores of four materials (P < 0.001. Immediately polished glass ionomer and compomer groups have significantly more microleakage than delayed polished groups (P < 0.001. Thermocycting could infulence the microleakage of composite on cervical edges (P < 0.05. Discussion. The precense of differences between the nature of materials and also the surface treatment such as primer or etchant application could influence the microleakage. The prescence of differences in reaction rate between the materials and the time that they reach to their adequate mechanical strength and adhesive bond strength lead to presence of differences between the effect of polishing time on the microleakage scores of materials.

  4. 铜抛光液中缓蚀剂5-氨基四唑(ATA)的作用机制研究%Investigation on the Mechanisms of Corrosion Inhibitor 5-aminotetrazole Used in the Copper Chemical Mechanical Polishing

    Institute of Scientific and Technical Information of China (English)

    刘宇宏; 董莹; 戴媛静; 雒建斌

    2012-01-01

    The influences of inhibitors ( benzotriazole( BTA)and 5-aminotetrazole( ATA) )in slurry with varying pH values on the chemical mechanical polishing( CMP) of copper were studied by the methods of the static corrosion, contact angle and X-ray photoelectron spectroscopy(XPS) ,and the effective mechanisms of ATA on copper surface were discussed. The results show that BTA and ATA are excellent copper corrosion inhibitors. In the range of pH values 3 - 10, the inhibitors form the passivity films and protect the copper surface from chemical attack, resulting in the decrease of the removal rates of copper and static corrosion rates,especially in the optimum condition of pH =4. ATA has better inhibition effect for copper corrosion than BTA in the range of pH =3 ~5, because ATA molecule can be preferentially adsorbed on copper surface by nitrogen atoms of amidogen and azole to form the protect films, resulting in the inhibition of the oxide formation from hydrogen peroxide and the improvement of the surface quality. In conclusion, ATA is one of the best inhibitors suitable for acid slurry of copper CMP.%采用静态腐蚀实验、接触角测试、XPS等手段,比较在不同pH值下抛光液中缓蚀剂(5-氨基四唑(ATA),苯并三唑(BTA))对铜表面化学机械抛光(CMP)的影响,并探讨ATA在铜表面的作用机制.结果表明,BTA和ATA是优良的铜缓蚀剂,当pH值为3~10时,两者可在铜表面成膜,保护铜表面不受腐蚀,从而降低铜片的静态腐蚀速率和去除率,其中当pH =4时,2种缓蚀剂表现出最佳的缓蚀性能.当pH值为3~5时,ATA的缓蚀性能优于BTA.ATA通过四唑环上的N原子和氨基上的N原子吸附在铜表面,形成保护膜,从而抑制了H2O2对铜表面的腐蚀,改善了表面质量,是一种优良的适用于酸性铜抛光液的缓蚀剂.

  5. 铜化学机械抛光中复合缓蚀剂的作用机制%Mechanisms of Mixed Corrosion Inhibitors in Copper Chemical Mechanical Polishing

    Institute of Scientific and Technical Information of China (English)

    龚桦; 王宁; 顾忠华; 潘国顺

    2013-01-01

    将复合缓蚀剂(苯并三氮唑(BTAH)和十二烷基磺酸钠(SDS))应用到铜的化学机械抛光液中,考察BTAH和SDS对铜表面化学机械抛光的影响,并探讨BTAH和SDS在铜表面的作用机制;分析BTAH和SDS抛光液中络合剂和表面活性剂对铜化学机械抛光性能的影响。结果表明:BTAH和SDS在铜表面形成了致密的Cu-BTAH和Cu-SDS保护膜,是优良的铜缓蚀剂。当以磷酸氢二胺(AHP)为络合剂,羟乙基纤维素(HEC)为表面活性剂时,优化后的BTAH和SDS抛光液取得了低至Ra0.2 nm的表面粗糙度,同时发现HEC有降低纳米颗粒残留的作用。%Mixed corrosion inhibitors(benzotriazole(BTAH)and sodium dodecyl sulfate(SDS))were utilized in copper chemical mechanical polishing(CMP)slurry.The influences of BTAH and SDS,complexing agent,and surfactant on the CMP of copper were studied,and the mechanisms of BTAH and SDS on copper surface were discussed.The results show that compact Cu-BTAH and Cu-SDS protective films are formed on the copper surface,and thus,which are excellent copper corrosion inhibitors.When using BTAH and SDS as mixed corrosion inhibitors,ammonium phosphate(AHP)as complexing agent,and hydroxy ethyl cellulose(HEC)as surfactant,a low surface roughness of 0.2 nm is got by this CMP slurry.The appearance of HEC in the slurry is found to be very effective in reducing the nano-sized particle deposition on copper surface.

  6. Polishing technique for beryllium mirror

    Science.gov (United States)

    Froechtenigt, J. F.

    1976-01-01

    Performance tests, accomplished by inserting entire X ray telescope and polished mirror into vacuum line 67 m long and taking photographs of an X ray resolution source, indicate that polishing increases mirror efficiency from 0.06 percent for X rays at 0.8 nm and increases resolution from 15 to 3.75 arc-seconds.

  7. Polish Americans. Second, Revised Edition.

    Science.gov (United States)

    Lopata, Helen Znaniecka

    This book examines Polonia, the Polish ethnic community in America created by three giant waves of immigration between 1880 and 1990. The complicated history of this ethnic group is reflected in the lives of increasing numbers of Polish Americans, including recent immigrants brought by political and economic changes, as they achieve middle class…

  8. Notions Catalog. Polish Functional Grammar.

    Science.gov (United States)

    Woytak, Lidia

    The Polish notions catalog systematizes a variety of informational codes used in Polish, resulting in lists of notions, each presented from a structural perspective. Where applicable, they are accompanied by a morphological component, structural chart, semantic description, frequentative expressions, and related vocabulary items. The notions…

  9. Reading Authentic Polish, Volume II.

    Science.gov (United States)

    Walczynski, Waldemar

    The second volume on reading authentic Polish is the continuation of a supplementary textbook to be used either in the classroom or in independent study. The materials included in it are unaltered authentic texts from Polish newspapers, magazines, and other mass media that provide exposure to the context and format of everyday reading matter. The…

  10. Subjective Quality of Life of Polish, Polish-Immigrant, and Polish-American Elderly.

    Science.gov (United States)

    Berdes, Celia; Zych, Adam A.

    2000-01-01

    Compares subjective quality of life of elderly Poles living in Poland, and Polish immigrants and Polish-American ethnics living in Chicago as part of a secondary data analysis of a study initially conducted in Poland. Conclusions lend support to the idea that U.S.-born elderly people and elderly immigrants to the United States have a significantly…

  11. Human Factors in Nuclear Power Engineering in Polish Conditions

    Directory of Open Access Journals (Sweden)

    Agnieszka Kaczmarek-Kacprzak

    2014-09-01

    Full Text Available The paper “Human factors in nuclear power engineering in Polish conditions” focuses on analysis of dynamics of preparing Polish society to build fi rst nuclear power plant in XXI century in Poland. Authors compare experience from constructing nuclear power plant Sizewell B (Great Britain and Sizewell C, which is in preparation phase with polish nuclear power program. Paper includes aspects e.g. of creating nuclear safety culture and social opinion about investment. Human factors in nuclear power engineering are as well important as relevant economical and technical factors, but very often negligible. In Poland where history about Czarnobyl is still alive, and social opinion is created on emotions after accident in Fukushima, human factors are crucial and should be under comprehensive consideration.

  12. Electrochemical Polishing Applications and EIS of a Novel Choline Chloride-Based Ionic Liquid

    Energy Technology Data Exchange (ETDEWEB)

    Wixtrom, Alex I. [Christopher Newport University, Newport News, VA (United States); Buhler, Jessica E. [Christopher Newport University, Newport News, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Abdel-Fattah, Tarek M. [Christopher Newport University, Newport News, VA (United States)

    2013-06-01

    Minimal surface roughness is a critical feature for high-field superconducting radio frequency (SRF) cavities used to engineer particle accelerators. Current methods for polishing Niobium cavities typically utilize solutions containing a mixture of concentrated sulfuric and hydrofluoric acid. Polishing processes such as these are effective, yet there are many hazards and costs associated with the use (and safe disposal) of the concentrated acid solutions. An alternative method for electrochemical polishing of the cavities was explored using a novel ionic liquid solution containing choline chloride. Potentiostatic electrochemical impedance spectroscopy (EIS) was used to analyze the ionic polishing solution. Final surface roughness of the Nb was found to be comparable to that of the acid-polishing method, as assessed by atomic force microscopy (AFM). This indicates that ionic liquid-based electrochemical polishing of Nb is a viable replacement for acid-based methods for preparation of SRF cavities.

  13. Effect of polishing on the microleakage of three different restorative materials: An in vitro study

    Directory of Open Access Journals (Sweden)

    Arnab Sengupta

    2014-01-01

    Full Text Available Aims and Objectives: The purpose of this in vitro study was to investigate the effect of polishing systems on the microleakage of three different restorative materials (Ketac Molar Easymix, Ketac N100 and Filtek P90. Materials and Methods: Class V cavities were prepared at the cemento-enamel junction of 60 freshly extracted premolars. The prepared teeth were randomly divided into three groups and restored with the three materials. The restored teeth were stored in distilled water at 37°C for 1 week. The restored teeth were then divided into two subgroups (polished and not polished of 10. Finishing and polishing of the polished group was done using the Sof-Lex polishing system. Furthermore, all the restorations were subjected to dye penetration testing. Results: Results showed that maximum microleakage was observed for the not polished group of Filtek P90 and least levels of microleakage were seen for the polished group of Ketac Molar Easymix. Conclusion: There was a significant difference seen when Ketac Molar Easymix was compared with Ketac N100 and Filtek P90 in terms of the extent of microleakage exhibited on polishing of the three materials; with the former exhibiting the least microleakage scores.

  14. Effect of polishing on the microleakage of three different restorative materials: an in vitro study.

    Science.gov (United States)

    Sengupta, Arnab; Gupta, Anil; Dagur, Renu

    2014-01-01

    The purpose of this in vitro study was to investigate the effect of polishing systems on the microleakage of three different restorative materials (Ketac Molar Easymix, Ketac N100 and Filtek P90). Class V cavities were prepared at the cemento-enamel junction of 60 freshly extracted premolars. The prepared teeth were randomly divided into three groups and restored with the three materials. The restored teeth were stored in distilled water at 37°C for 1 week. The restored teeth were then divided into two subgroups (polished and not polished) of 10. Finishing and polishing of the polished group was done using the Sof-Lex polishing system. Furthermore, all the restorations were subjected to dye penetration testing. Results showed that maximum microleakage was observed for the not polished group of Filtek P90 and least levels of microleakage were seen for the polished group of Ketac Molar Easymix. There was a significant difference seen when Ketac Molar Easymix was compared with Ketac N100 and Filtek P90 in terms of the extent of microleakage exhibited on polishing of the three materials; with the former exhibiting the least microleakage scores.

  15. Effects of a paste-free prophylaxis polishing cup and various prophylaxis polishing pastes on tooth enamel and restorative materials.

    Science.gov (United States)

    Covey, David A; Barnes, Caren; Watanabe, Hidehiko; Johnson, William W

    2011-01-01

    The application of cleaning and polishing agents to a patient's dentition is a routine part of many dental practices. This study measured the surface roughness and surface gloss of tooth enamel, composite resin, and dental porcelain restorative materials when exposed to a paste-free prophylaxis polishing cup as well as a conventional prophylaxis polishing paste. Samples of human tooth enamel, a composite resin restorative material, and dental porcelain were prepared by a series of polishing papers to produce a flat smooth surface. The baseline average surface roughness (Ra) was measured using a contact stylus profilometer, and the surface gloss was measured with a glossmeter. The test samples were subjected to a standardized polishing routine using a paste-free prophylaxis polishing cup and a fine- or coarse-particle prophylaxis paste. Post-treatment surface roughness and gloss measurements were compared using a paired t statistical test. The conventional prophylaxis pastes increased surface roughness and decreased the gloss of the composite resin and tooth enamel test groups. The paste-free cups did not significantly affect the surface roughness of the enamel or the restorative materials. Dental porcelain surface roughness essentially was not affected by the application of paste-free cups and the fine and coarse pastes.

  16. Foreign direct investment in the Polish economy

    Directory of Open Access Journals (Sweden)

    Tomasz Gutowski

    2013-06-01

    Full Text Available Foreign Direct Investment (FDI plays an extraordinary and increasingly important role in global and local business. This type of investment gives the country a better position to prepare for rapidly changing economic conditions. Considering the external effects of FDI, it should be assumed that the most important one is coinvolvement in the development of a country in which they are located. In the Polish economy the value of foreign direct investment is very high and it is one of the most important causes of the economic growth.

  17. Optimized Control for Dynamical Performance of the Polishing Robot in Unstructured Environment

    Directory of Open Access Journals (Sweden)

    Zhong Luo

    2011-01-01

    Full Text Available In this paper, the dynamical performance of polishing robot working in unstructured environment is investigated. Structure mechanism and operating principle of a polishing robot are introduced firstly, and its dynamical model is established. Then, a S-shaped acceleration-deceleration path planning method and a human-simulated intelligent control (HSIC strategy are proposed. The S-shaped acceleration-deceleration path planning method is to switch the magnitude and direction of the abrupt velocities between motion sections in order to improve the work efficiency, the smoothness of movement and the processing accuracy. The HSIC control strategy is built based on the unstructured environment information measured by ultrasonic sensors, in which the appropriate programs prepared in advance are determined according to the size and sign of both the control error and its change rate. Simulation results show that the intelligent control strategy combining with optimum path planning method are effective to reduce the structure vibration, to improve the stability and the control accuracy of the polishing robot system.

  18. Polishing of denture base acrylic resin with chairside polishing kits: an SEM and surface roughness study.

    Science.gov (United States)

    Chatzivasileiou, Konstantinos; Emmanouil, Ioannis; Kotsiomiti, Eleni; Pissiotis, Argirios

    2013-01-01

    Heat-cured acrylic resin specimens were polished using either conventional laboratory polishing, sandpaper, or three commercial chairside kits. The surface roughness of the polished specimens was measured with a contact profilometer. Scanning electron microscopy was used to obtain microphotographs of the polished surfaces. Laboratory polishing produced the smoothest surfaces in all cases, while sandpaper application produced the roughest. Use of the chairside polishing kits resulted in significantly rougher surfaces compared to those produced by laboratory polishing. Nonetheless, polishing of trimmed denture bases using chairside polishing kits is an effective alternative procedure for cases in which the laboratory procedure is not applicable.

  19. Polishing gold and gold-alloy crystals

    Science.gov (United States)

    Doty, J. P.

    1976-01-01

    Sawed cross-section samples are rough polished at minimum pressure with 14 micron grit. After saw marks are polished away, polishing grit is changed to 0.05 micron. When smooth appearance is attained, surface is then chemically polished by hand in dust free room.

  20. Effect of electrochemical polishing time on surface topography of mild steel

    Institute of Scientific and Technical Information of China (English)

    Baocheng Wang; Jinhua Zhu

    2007-01-01

    The variation in altitude density function (ADF) of the surface topography of mild steel during electrochemical polishing (ECP) was investigated, and the mechanism of the variation of surface roughness with polishing time was analyzed. The results show that the variation trend of ADF with polishing time is flat-steep-flat; the variation of surface roughness results in the different distributions of surface current density, and there is a fine surface smoothness in the special period of ECP from 4 to 8 s.

  1. Tooth polishing: The current status.

    Science.gov (United States)

    Sawai, Madhuri Alankar; Bhardwaj, Ashu; Jafri, Zeba; Sultan, Nishat; Daing, Anika

    2015-01-01

    Healthy teeth and gums make a person feel confident and fit. As people go about their daily routines and with different eating and drinking habits, the tooth enamel turns yellowish or gets stained. Polishing traditionally has been associated with the prophylaxis procedure in most dental practices, which patients know and expect. However, with overzealous use of polishing procedure, there is wearing of the superficial tooth structure. This would lead to more accumulation of local deposits. Also, it takes a long time for the formation of the fluoride-rich layer of the tooth again. Hence, now-a-days, polishing is not advised as a part of routine oral prophylaxis procedure but is done selectively based on the patients' need. The article here, gives an insight on the different aspects of the polishing process along with the different methods and agents used for the same.

  2. Tooth polishing: The current status

    Directory of Open Access Journals (Sweden)

    Madhuri Alankar Sawai

    2015-01-01

    Full Text Available Healthy teeth and gums make a person feel confident and fit. As people go about their daily routines and with different eating and drinking habits, the tooth enamel turns yellowish or gets stained. Polishing traditionally has been associated with the prophylaxis procedure in most dental practices, which patients know and expect. However, with overzealous use of polishing procedure, there is wearing of the superficial tooth structure. This would lead to more accumulation of local deposits. Also, it takes a long time for the formation of the fluoride-rich layer of the tooth again. Hence, now-a-days, polishing is not advised as a part of routine oral prophylaxis procedure but is done selectively based on the patients′ need. The article here, gives an insight on the different aspects of the polishing process along with the different methods and agents used for the same.

  3. Fused-Polished Fiber Couplers

    Institute of Scientific and Technical Information of China (English)

    Sien; Chi; Shiao-Min; Tseng

    2003-01-01

    We report on fused-polished fiber couplers with a new fabrication method. This structure so fabricated is promising while achieving high-performance all-fiber WDM devices. Potential advantages and prospects of our works are presented.

  4. Astronarium - Filmography of Polish Astronomy

    Science.gov (United States)

    Radajewski, Bogumił; Mikołajewski, Maciej; Czart, Krzysztof; Guz, Iwona; Rubaszewski, Adam; Stelmach, Tomasz

    2016-06-01

    ``Astronarium'' is a series of TV programs about astronomy and space research co-produced by the Polish Astronomical Society and Polish Television. It has been planned for three seasons and 34 episodes in total (8, 13 and 13 per season). The first season was presented in March and April 2015 and the second started in September 2015. The third one is planned for 2016. ``Astronarium'' has been broadcast on the nationwide channel TVP Regionalna, which later changed its name to TVP 3.

  5. Sediment losses from forest management: mechanical vs. chemical site preparation after clearcutting

    Energy Technology Data Exchange (ETDEWEB)

    Beasley, R.S.; Granillo, A.B.; Zillmer, V.

    The comparative effects of mechanical and chemical site preparation water yields and sediment losses following forest clearcutting were evaluated over a 4-yr period in the Athens Plateau area of southwestern Arkansas. After 1 yr of pretreatment measurements, three forested water sheds were clearcut and the residual vegetation and debris were sheared and windrowed but not burned. Three watersheds were clearcut in a similar manner, but received chemical site preparation. Residual trees on two watersheds were injected with 2-4, D amine; the third watershed was aerially sprayed with a mixture of Tordon (active ingredient: picloram (4-amino-3,5,6-trichloropicoline acid)) and Garlon (active ingredient; triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid)). Three additional watersheds were left undisturbed for controls. Mean annual sediment losses on the mechanically, site prepared watersheds during the first posttreatment year were significantly higher than those from either the chemically site prepared watersheds or controls. Chemical site preparation did not significantly increase sediment losses. Although 2nd yr losses for the mechanical site preparation and control treatments doubled over 1st-yr levels, no significant treatment effect was detected for either site preparation treatment. Third-year losses decreased below 1st-yr losses for all treatments but not to pretreatment year levels. The relatively sharp declines in sediment losses during the third posttreatment year were attributed to rapid regrowth of natural vegetation on the sites.

  6. Electrochemical polishing of notches

    Science.gov (United States)

    Kephart, Alan R.; Alberts, Alfred H.

    1989-01-01

    An apparatus and method are disclosed for the selective electrochemical polishing of a lateral tip of a deep longitudinal notch in a work piece used to test crack initiation properties of materials. A DC power source is connected to the work piece and to an electrode disposed laterally along the distal end of an insulated body which is inserted in the longitudinal notch. The electrode and distal end of the body are disposed along the tip of the notch, but are spaced from the notch so as to provide a lateral passage for an electrolyte. The electrolyte is circulated through the passage so that the electrolyte only contacts the work piece adjacent the passage. Conveniently, the electrolyte is circulated by use of an inlet tube and an outlet tube provided at opposite ends of the passage. These tubes are preferably detachably located adjacent the ends of the passage and suitable seals are provided. A holding device including arms to which the tubes are attached is conveniently used to rapidly and easily locate the test specimen with the passage aligned with the tubes. The electrode is preferably a wire which is located in grooves along the distal end of the insulated body and up one side of the body or a plastic sheath insulated thin metal strip.

  7. [Effect of infiltration technique and polishing on the roughness of artificial carious enamel surfaces].

    Science.gov (United States)

    Yuan, Chang-qing; Dou, Guo-wen; Deng, Jing; Geng, Guo-liang; Sun, Pei; Cao, Ying-xiu

    2013-08-01

    To study the surface roughness of early carious lesions which were treated with resin infiltration and polished with different materials, and to provide reference for selection of appropriate polishing system. Fifty-four labial surface specimens of mandibular incisors were created out of bovine teeth. They were randomly divided into 6 groups. One group was sound enamel group. Another group was early enamel carious group. Other specimens were treated with a partially saturated acidic buffer solution for preparation of initial artificial enamel caries. These initial artificial enamel caries were treated with resin infiltration. Then they were randomly divided into 4 groups according to polishing or not and type of polishing tool (rubber cups, polishing discs, HiLuster polishers). The surface roughness of specimens in all groups were measured with Form Talysurf PGI 800. Arithmetical mean deviation of the assessed profile (Ra) and the maximum height of the profile(Rz) were used as measurement parameter. SPSS 17.0 software package was used for data analysis. Comparison of sound enamel surfaces and early carious surfaces revealed no significant difference in surface roughness(P>0.05), but the mean value of the latter one was higher. After infiltration, the roughness of surfaces without polishing was significantly higher than that of early carious surfaces(P0.05). The roughness of polishing groups after infiltration was significantly smaller than that of group without polished after infiltration (Pcarious surfaces revealed no significant difference in surface roughness (P>0.05). After early caries being treated with infiltration technique, the roughness of teeth surfaces increases significantly. Those surfaces should be polished. Rubber cup and polishing discs with smaller granularity are more effective and reasonable as the surface polishing materials.

  8. Laser polishing of niobium for superconducting radio-frequency accelerator applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Liang [William and Mary College; Klopf, John M. [William and Mary College; Reece, Charles E. [JLAB; Kelley, Michael J. [JLAB

    2014-08-01

    Interior surfaces of niobium cavities used in superconducting radio frequency accelerators are now obtained by buffered chemical polish and/or electropolish. Laser polishing is a potential alternative, having advantages of speed, freedom from noxious chemistry and availability of in-process inspection. We studied the influence of the laser power density and laser beam raster rate on the surface topography. These two factors need to be combined carefully to smooth the surface without damage. Computational modeling was used to estimate the surface temperature and gain insight into the mechanism of laser polishing. Power spectral density analysis of surface topography measurements shows that laser polishing can produce smooth topography similar to that obtained by electropolish. This is a necessary first step toward introducing laser polishing as an alternative to the currently practiced chemical polishing.

  9. Research progress in tribo-electrochemistry and tribo-electrochemical polishing

    Institute of Scientific and Technical Information of China (English)

    ZHAI Wenjie

    2007-01-01

    In this paper, the status quo and recent progress in the research on tribo-electrochemistry in aqueous and non-aqueous media, respectively, are reviewed. Much more attention has been paid to the tribo-electrochemical mechanisms for the control of friction and wear. Based on a summary of the conventional polishing principles of hard and brittle materials, the tribo-electrochemical polishing method is proposed. The results of the preliminary test show that tribo-electrochemical polishing is promising to become a critical technology in the high efficient polishing and planarization of microelectronic materials.

  10. Tunable multicolor carbon dots prepared from well-defined polythiophene derivatives and their emission mechanism.

    Science.gov (United States)

    Guo, Liang; Ge, Jiechao; Liu, Weimin; Niu, Guangle; Jia, Qingyan; Wang, Hui; Wang, Pengfei

    2016-01-14

    Various functional precursors based on polythiophene derivatives are designed to prepare carbon dots (C-dots) with tunable emissions ranging from blue to near-infrared (NIR) at a single excitation wavelength (400 nm). The as-prepared C-dots demonstrate homogeneous size, superior optical properties, excellent water solubility, and low cytotoxicity. Thus, the C-dots are candidates for bio-imaging. A tunable photoluminescence mechanism is proposed to result from variations in the surface state and N content.

  11. Effects of PVP on the preparation and growth mechanism of monodispersed Ni nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Monodispersed Ni nanoparticles were successfully prepared by chemical reduction with hydrazine hydrate in ethylene glycol.The effect of the amount of polyvinylpyrrolidone (PVP-K30) on the preparation of Ni nanoparticles was investigated.X-ray diffraction (XRD),transmission electron microscopy (TEM),and high resolution transmission electron microscopy (HRTEM) were employed to characterize the nickel particles are spherical in shape and are not agglomerated.A possible extensive mechanism of nickel nanoparticle formation has been suggested.

  12. 钨的化学机械抛光过程中TiN-W电偶的腐蚀行为%Galvanic Corrosion of TiN-W Electro-couple During Tungsten Chemical Mechanical Polishing

    Institute of Scientific and Technical Information of China (English)

    程璇; 林昌健

    2001-01-01

    Chemical-mechanical polishing (CMP) is a process whereby mechanical and chemical forces are combined to remove material from a wafer and polish it to a flat surface. Tungsten CMP is an important process to gain the global planarity of silicon wafers with tungsten (W) plugs. Tungsten is actually deposited on a thin adhesive layer of titanium nitride (TiN) on silicon. When close to the final stage of polishing, TiN and W will be simultaneously exposed to the polishing chemistry, forming a galvanic couple. The corrosion of TiN and W couple will result in different polish rate.   This work studied the potential difference and galvanic currents on particulate contamination of the abrasive on the patterned surface and on corrosion behaviors of TiN and W. The polarization curves of TiN and W were, respectively, obtained in 0.01 mol/L KNO3 solutions in the absence and presence of three typical oxidants (H2O2, KIO3, Fe(NO3)3) by DC polarization technique. The corrosion potentials and galvanic currents were measured when TiN and W were placed in a specially designed electrochemical cell to form electro-couple. The preliminary results revealed that the corrosion rate of TiN-W electro-couple significantly increased in the presence of 4.5% H2O2 at pH 4.0, while reduced to the minimal in the presence of Fe(NO3)3 at pH 1.5. Agitation significantly enhanced the corrosion rate of TiN-W couple.%化学机械抛光(CMP)技术是同时利用化学和机械作用来获得固体表面亚微米尺度上平整性非常有效的方法,从90年代初期起已成为制备高质量镜头和镜面及集成电路制造过程中硅片表面预处理工艺中最常用的技术之一.钨的化学机械抛光是用钨坯获得硅片球面平整度的重要工艺.其过程实际上是先将钨沉积到硅上已有的薄粘附层-氮化钛上,然后进行化学机械抛光.当抛光阶段接近终了时,氮化钛和钨表面将同时暴露在化学抛光液中形成电偶对,并在界

  13. Polish Toxic Currency Options

    Directory of Open Access Journals (Sweden)

    Waldemar Gontarski

    2009-04-01

    Full Text Available Toxic currency options are defined on the basis of the opposition to the nature (essence of an option contract, which is justified in terms of norms founded on the general law clause of characteristics (nature of a relation (which represents an independent premise for imposing restrictions on the freedom of contracts. So-understood toxic currency options are unlawful. Indeed they contravene iuris cogentis regulations. These include for instance option contracts, which are concluded with a bank, if the bank has not informed about option risk before concluding the contract; or the barrier options, which focus only on the protection of banks interests. Therefore, such options may appear to be invalid. Therefore, performing contracts for toxic currency options may be qualified as a criminal mismanagement. For the sake of security, the manager should then take into consideration filing a claim for stating invalidity (which can be made in a court verdict. At the same time, if the supervisory board member in a commercial company, who can also be a subject to mismanagement offences, commits an omission involving lack of reaction (for example, if he/she fails to notify of the suspected offence committed by the management board members acting to the companys detriment when the management board makes the company conclude option contracts which are charged with absolute invalidity the supervisory board member so acting may be considered to act to the companys detriment. In the most recent Polish jurisprudence and judicature the standard of a good host is treated to be the last resort for determining whether the managers powers resulting from criminal regulations were performed. The manager of the exporter should not, as a rule, issue any options. Issuing options always means assuming an obligation. In the case of currency put options it is an absolute obligation to purchase a given amount in euro at exchange rate set in advance. On the other hand issuing

  14. Terminology extraction from medical texts in Polish.

    Science.gov (United States)

    Marciniak, Małgorzata; Mykowiecka, Agnieszka

    2014-01-01

    Hospital documents contain free text describing the most important facts relating to patients and their illnesses. These documents are written in specific language containing medical terminology related to hospital treatment. Their automatic processing can help in verifying the consistency of hospital documentation and obtaining statistical data. To perform this task we need information on the phrases we are looking for. At the moment, clinical Polish resources are sparse. The existing terminologies, such as Polish Medical Subject Headings (MeSH), do not provide sufficient coverage for clinical tasks. It would be helpful therefore if it were possible to automatically prepare, on the basis of a data sample, an initial set of terms which, after manual verification, could be used for the purpose of information extraction. Using a combination of linguistic and statistical methods for processing over 1200 children hospital discharge records, we obtained a list of single and multiword terms used in hospital discharge documents written in Polish. The phrases are ordered according to their presumed importance in domain texts measured by the frequency of use of a phrase and the variety of its contexts. The evaluation showed that the automatically identified phrases cover about 84% of terms in domain texts. At the top of the ranked list, only 4% out of 400 terms were incorrect while out of the final 200, 20% of expressions were either not domain related or syntactically incorrect. We also observed that 70% of the obtained terms are not included in the Polish MeSH. Automatic terminology extraction can give results which are of a quality high enough to be taken as a starting point for building domain related terminological dictionaries or ontologies. This approach can be useful for preparing terminological resources for very specific subdomains for which no relevant terminologies already exist. The evaluation performed showed that none of the tested ranking procedures were

  15. Polish-German bilingualism at school. A Polish perspective

    Directory of Open Access Journals (Sweden)

    Pulaczewska, Hanna

    2014-03-01

    Full Text Available This article presents the institutional frames for the acquisition of Polish literacy skills in Germany and the maintenance of Polish-German bilingualism after the repatriation of bilingual children to Poland. These processes are examined in the context of recent developments in the European domestic job market. While the European Union has placed proficiency in several languages among its educational objectives, and foreign languages have been made obligatory school subjects in all member countries, the potential advantages of internal European migrations for producing high-proficiency bilinguals are being ignored. Bilingualism resulting from migration and biculturalism enjoys little social prestige in the host countries. In Germany, there is significant regional variation in how school authorities react to challenges posed by the presence of minority languages. In many cases, the linguistic potential of many second-generation migrants and re-emigrants gets largely wasted because of lacking interest and incentives from German and Polish institutions alike.

  16. Compressibility of nanostructured Fe-Cu materials prepared by mechanical milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Olsen, J.S.; Gerward, Leif

    1999-01-01

    The compressibility of nanostructured Fe-Cu materials prepared by mechanical milling has been investigated by in-situ high-pressure x-ray diffraction using synchrotron radiation. It is found that the bulk modulus of both fcc-Cu and bcc-Fe phases decreases with decreasing grain sizes. The unstable...... ferromagnetic fcc-FeCu solid solution prepared by mechanical alloying has a bulk modulus of about 85 GPa, which is much smaller than the corresponding values for bulk fcc-Cu and bcc-Fe....

  17. Preparation and Mechanical Properties of Layered Double Hydrotalcides/ /Polystyrene Nanocomposites Prepared by an in-situ Bubble Stretching Method

    Directory of Open Access Journals (Sweden)

    Xiu-ting ZHENG

    2014-12-01

    Full Text Available Layered double hydrotalcides/polystyrene (LDHs/PS nanocomposites were produced by an in-situ bubble stretching (ISBS method and simple shear method; the effect of LHDs content on the dispersion and the mechanical properties of nanocomposites was studied. The field emission scanning electron microscopy (FE-SEM images indicated that the ISBS method leads to a high degree of dispersion of LDHs nanoparticles in PS matrix. Furthermore, it did not form a significant re-aggregation after defoaming by means of twin-screw extruder. Compared with the simple shear method, the un-notched impact strength and tensile strength of nanocomposites prepared by ISBS method were higher at the same amount of LDHs. The un-notched impact strength of the nanocomposites prepared by ISBS method reached a maximum value at the LDHs mass fraction of 5 % , the strength increased is 57.29 % greater than that of pure PS. The enhanced mechanical properties attributed to the effective dispersion of nanoscale LDHs by ISBS method. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6197

  18. Surface roughness and morphology of resin composites polished with two-step polishing systems.

    Science.gov (United States)

    Can Say, Esra; Yurdagüven, Haktan; Yaman, Batu Can; Özer, Füsun

    2014-01-01

    The purpose of this study was to investigate surface roughness (Ra) and morphology of supra-nanofilled [Estelite Omega (EO), Estelite ∑ Quick (EQ)], micro-hybrid [Esthet.X HD (EHD), G-aenial (GAE)] and nano-hybrid [Clearfil Majesty Posterior (CMP), Charisma Diamond (CD), Beautifil II (BII)] composites polished with two-step polishing systems [Enhance/PoGo (EP); Venus Supra (VS)]. Composite discs, 30 of each type, were prepared. Each composite group was divided into three subgroups: Mylar (control), EP and VS. Ra was evaluated with profilometer. In each composite group, the control had the lowest Ra. With both polishing systems, EO and EQ had significantly the lowest Ra, whereas CMP and BII had the highest. Except for GAE, CD and BII, the differences in Ra between EP and VS in each composite group were significant, showing smoother surfaces for EP. Supra-nanofilled composites created smoother surfaces than nano-hybrids, and their performance was similar or slightly better than that of micro-hybrids.

  19. Sensing roughness and polish direction

    Science.gov (United States)

    Jakobsen, M. L.; Olesen, A. S.; Larsen, H. E.; Stubager, J.; Hanson, S. G.; Pedersen, T. F.; Pedersen, H. C.

    2016-04-01

    As a part of the work carried out on a project supported by the Danish council for technology and innovation, we have investigated the option of smoothing standard CNC machined surfaces. In the process of constructing optical prototypes, involving custom-designed optics, the development cost and time consumption can become relatively large numbers in a research budget. Machining the optical surfaces directly is expensive and time consuming. Alternatively, a more standardized and cheaper machining method can be used, but then the object needs to be manually polished. During the polishing process the operator needs information about the RMS-value of the surface roughness and the current direction of the scratches introduces by the polishing process. The RMS-value indicates to the operator how far he is from the final finish, and the scratch orientation is often specified by the customer in order to avoid complications during the casting process. In this work we present a method for measuring the RMS-values of the surface roughness while simultaneously determining the polishing direction. We are mainly interested in the RMS-values in the range from 0 - 100 nm, which corresponds to the finish categories of A1, A2 and A3. Based on simple intensity measurements we estimates the RMS-value of the surface roughness, and by using a sectioned annual photo-detector to collect the scattered light we can determine the direction of polishing and distinguish light scattered from random structures and light scattered from scratches.

  20. New development of atmospheric pressure plasma polishing

    Institute of Scientific and Technical Information of China (English)

    Bo Wang; Jufan Zhang; Shen Dong

    2009-01-01

    Atmospheric pressure plasma polishing (APPP) is a precision machining technology used for manufacturing high quality optical surfaces. The changes of surface modulus and hardness after machining prove the distinct improvement of surface mechanical properties. The demonstrated decrease of surfacc residual stresses testifies the removal of the former deformation layer.And the surface topographies under atomic force microscope (AFM) and scanning electron microscope (SEM) indicate obvious amelioration of the surface status,showing that the 0.926-nm average surface roughness has been achieved.

  1. Challenges of sample preparation for cross sectional EBSD analysis of electrodeposited nickel films

    DEFF Research Database (Denmark)

    Alimadadi, Hossein; Pantleon, Karen

    2009-01-01

    . Different procedures for sample preparation including mechanical grinding and polishing, electropolishing and focused ion beam milling have been applied to a nickel film electrodeposited on top of an amorphous Ni-P layer on a Cu-substrate. Reliable EBSD analysis of the whole cross section can be obtained...

  2. Polishing of dental porcelain by polycrystalline diamond.

    Science.gov (United States)

    Nakamura, Yoshiharu; Sato, Hideaki; Ohtsuka, Masaki; Hojo, Satoru

    2010-01-01

    Polycrystalline diamond (PCD) exhibits excellent abrasive characteristics and is commonly used as loose grains for precision machining of hard ceramics and other materials that are difficult to grind and polish. In the present study, we investigated using bonded PCD for polishing dental porcelain, for which a lustrous surface is difficult to obtain by polishing. We compared the surface texture and characteristics of dental porcelain after polishing with bonded PCD with that obtained using bonded monocrystalline diamond (MCD), which is commonly used for this purpose. Polishing was performed at various pressures and rotational speeds on a custom-built polishing apparatus using bonded PCD or MCD with grain sizes of 3.92 μm on specimens consisting of VITA Omega 900 dentin porcelain after firing and then glazing to a specified surface roughness. The surface roughness of the polished porcelain and the abrasion quantity in terms of its polishing depth were measured, and its surface texture and characteristics were investigated. At low polishing pressures, PCD yielded a finer polished surface than MCD. The polishing depth after polishing for 20-30 min was approximately 2-3 μm with PCD and 1-2 μm with MCD. The polished surface was more uniform and smooth with PCD than with MCD.

  3. Preparation

    Directory of Open Access Journals (Sweden)

    M.M. Dardir

    2014-03-01

    Full Text Available Some hexanamide-mono and di-linoleniate esters were prepared by the reaction of linolenic acid and hexanamide (derived from the reaction of hexanoic acid and diethanolamine. The chemical structure for the newly prepared hexanamide-mono and di-linoleniate esters were elucidated using elemental analysis, (FTIR, H 1NMR and chemical ionization mass spectra (CI/Ms spectroscopic techniques. The results of the spectroscopic analysis indicated that they were prepared through the right method and they have high purity. The new prepared esters have high biodegradability and lower toxicity (environmentally friendly so they were evaluated as a synthetic-based mud (ester-based mud for oil-well drilling fluids. The evaluation included study of the rheological properties, filtration and thermal properties of the ester based-muds formulated with the newly prepared esters compared to the reference commercial synthetic-based mud.

  4. Sensing roughness and polish direction

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Olesen, Anders Sig; Larsen, Henning Engelbrecht;

    2016-01-01

    needs information about the RMS-value of the surface roughness and the current direction of the scratches introduced by the polishing process. The RMS-value indicates to the operator how far he is from the final finish, and the scratch orientation is often specified by the customer in order to avoid...... complications during the casting process. In this work we present a method for measuring the RMS-values of the surface roughness while simultaneously determining the polishing direction. We are mainly interested in the RMS-values in the range from 0 – 100 nm, which corresponds to the finish categories of A1, A2...... and A3 (Finishing guide, Bales). Based on simple intensity measurements, we estimate the RMS-value of the surface roughness, and by using a sectioned annually shaped photo-detector to collect the scattered light, we can determine the direction of polishing and distinguish light scattered from random...

  5. Mechanical Property of Low Chromium Semi-Steel Grinding Ball Prepared by Cross Rolling

    Institute of Scientific and Technical Information of China (English)

    CHANG Li-min; MENG De-liang; NIE Pu-lin; LIU Jian-hua

    2004-01-01

    The preparing method, rolling technology and mechanical properties of low chromium semi-steel grinding ball by cross rolling were studied. The results show that when the low chromium semi-steel bar is forged from 55 mm to 50 mm, cross-rolled into grinding ball at 1 000-1 050 ℃, air cooled and tempered at 550 ℃ for 2 h, the best mechanical properties, especially the abrasive resistance under the action of hard abrasive, can be obtained.

  6. Polishing the Whole Act.

    Science.gov (United States)

    McInerney, John

    There are many ideas for class activities in a first grade whole language classroom that can make the class a richer environment without requiring a lot of time or preparation. "Whole language" is not a set of practices to teach reading; it is a set of beliefs, a philosophy about learning which derives from the notion of keeping learning…

  7. Graphite Composite Panel Polishing Fixture

    Science.gov (United States)

    Hagopian, John; Strojny, Carl; Budinoff, Jason

    2011-01-01

    The use of high-strength, lightweight composites for the fixture is the novel feature of this innovation. The main advantage is the light weight and high stiffness-to-mass ratio relative to aluminum. Meter-class optics require support during the grinding/polishing process with large tools. The use of aluminum as a polishing fixture is standard, with pitch providing a compliant layer to allow support without deformation. Unfortunately, with meter-scale optics, a meter-scale fixture weighs over 120 lb (.55 kg) and may distort the optics being fabricated by loading the mirror and/or tool used in fabrication. The use of composite structures that are lightweight yet stiff allows standard techniques to be used while providing for a decrease in fixture weight by almost 70 percent. Mounts classically used to support large mirrors during fabrication are especially heavy and difficult to handle. The mount must be especially stiff to avoid deformation during the optical fabrication process, where a very large and heavy lap often can distort the mount and optic being fabricated. If the optic is placed on top of the lapping tool, the weight of the optic and the fixture can distort the lap. Fixtures to support the mirror during fabrication are often very large plates of aluminum, often 2 in. (.5 cm) or more in thickness and weight upwards of 150 lb (68 kg). With the addition of a backing material such as pitch and the mirror itself, the assembly can often weigh over 250 lb (.113 kg) for a meter-class optic. This innovation is the use of a lightweight graphite panel with an aluminum honeycomb core for use as the polishing fixture. These materials have been used in the aerospace industry as structural members due to their light weight and high stiffness. The grinding polishing fixture consists of the graphite composite panel, fittings, and fixtures to allow interface to the polishing machine, and introduction of pitch buttons to support the optic under fabrication. In its

  8. Polishing compound for plastic surfaces

    Science.gov (United States)

    Stowell, Michael S.

    1995-01-01

    A polishing compound for plastic surfaces. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains fine particles silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS.TM., LEXAN.TM., LUCITE.TM., polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired.

  9. Polishing compound for plastic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Stowell, M.S.

    1993-01-01

    A polishing compound for plastic surfaces is disclosed. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains colloidal silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS{sup TM}, LEXAN{sup TM}, LUCITE{sup TM}, polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired.

  10. The influence of Mechanical bowel preparation in elective colorectal surgery for diverticulitis

    NARCIS (Netherlands)

    H.P. van 't Sant (Hans Pieter); J.C. Slieker (Juliette); W.C.J. Hop (Wim); W.F. Weidema (Wibo); J.F. Lange (Johan); J. Vermeulen (Jefrey); C.M.E. Contant

    2012-01-01

    textabstractBackground: Mechanical bowel preparation (MBP) has been shown to have no influence on the incidence of anastomotic leakage in overall colorectal surgery. The role of MBP in elective surgery in combination with an inflammatory component such as diverticulitis is yet unclear. This study ev

  11. Surface texture and some properties of acrylic resins submitted to chemical polishing.

    Science.gov (United States)

    Braun, K O; Mello, J A N; Rached, R N; Del Bel Cury, A A

    2003-01-01

    The effects of chemical polishing on dental acrylic resin properties are not well clarified. This study evaluated the effect of chemical and mechanical polishing on the residual monomer release (RM), Knoop hardness (KH), transverse strength (TS) and surface texture (ST) of a heat- and self-cured acrylic resin. Four groups were formed: GI-self-cured resin/mechanical polishing; GII-self-cured resin/chemical polishing; GIII-heat-cured resin/mechanical polishing; GIV-heat-cured resin/chemical polishing. Following the polishing procedures, specimens were stored in distilled water at 37 degrees C. The KH and RM measurements were taken after 1, 2, 8 and 32 days of storage, and TS after 2, 8 and 32 days. Surface texture was observed under SEM evaluation. Results were compared statistically at a confidence level of 95%. The following conclusions were drawn: (1) regardless of the acrylic resin and the period of analysis, chemical polishing increased RM levels, reduced KH, and did not affect TS significantly; (2) water storage increased the surface hardness of GII and GIV; (3) GII and GIV showed a smooth and wavy surface under SEM evaluation.

  12. Research on a mechanical polishing method for stainless steel electric kettle surface%不锈钢电水壶曲面机械抛光方法研究

    Institute of Scientific and Technical Information of China (English)

    吴昌林; 范青荣; 耿金龙; 金逸

    2011-01-01

    为解决不锈钢电热水壶在手工抛光方式中存在的污染严重、抛光效率低和质量不稳定等问题,成功自主研发了一套电水壶曲面自动化机械抛光系统,该系统采用了多磨具多工位的抛光方法,可夹持三个水壶同时进行抛光,提高了抛光效率.为确保水壶表面抛光质量,规划了螺旋式刀具路径,同时提出了基于示教法的抛光刀位数据生成方法,并利用NURBS曲线拟合的方法对刀具轨迹进行优化.实验结果证明,与手工抛光方式相比较,该方法大大提高了抛光质量和效率.%To resolve the problems of manual polishing for stainless steel electric kettle,such as,serious pollution, low efficiency and unstable quality,an automatic polishing system for stainless steel electric kettle surface was successfully developed.The system adopted the method of multi-abrasive and multi-station, which can polish three kettles in a time and improve the polishing efficiency; making sure of the polishing quality of kettle surface,the spiral tool path was planed,meanwhile a method of data generating for cutter location with teaching method was recommended and a method of optimal path engendered with NURBS curve fitting was used to optimize the tool path.The experimental result proves that this method can produce higher polishing quality and efficiency compared with manual polishing.

  13. Semiological analysis of Polish theater posters

    OpenAIRE

    Jelena Nikolić; Uroš Nedeljković

    2016-01-01

    Through the application of semiological analysis to theater posters made by two Polish authors, the paper uncovers signs, meanings, codes and specifics of the „Polish school of poster-making“ and contemporary Polish posters. Aside from this, I suggest a methodological framework for studying the issue of coding and shaping a theater poster as a culturally specific form of visual communication. The aesthetic and semiotic outlook of the Polish theater posters which were chosen is analyzed using ...

  14. Polish-Bulgarian-Russian, Bulgarian-Polish-Russian or Russian-Bulgarian-Polish dictionary?

    Directory of Open Access Journals (Sweden)

    Violetta Koseska-Toszewa

    2015-11-01

    Full Text Available Polish-Bulgarian-Russian, Bulgarian-Polish-Russian or Russian-Bulgarian-Polish dictionary? The trilingual dictionary (M. Duszkin, V. Koseska, J. Satoła and A. Tzoneva is being elaborated based on a working Polish-Bulgarian-Russian electronic parallel corpus authored by Maksim Duszkin, Violetta Koseska-Toszewa and Joanna Satoła-Staśkowiak, and works by A. Tzoneva. It is the first corpus comparing languages belonging to three different Slavic language groups: western, southern and eastern. Works on the dictionary are based on Gramatyka konfrontatywna bułgarsko-polska (Bulgarian-Polish confrontative grammar and the proposed there semantic-oriented interlanguage. Two types of classifiers have been introduced into the dictionary: classic and semantic. The trilingual dictionary will present a consistent and homogeneous set of facts of grammar and semantics. The Authors point out that in a traditional dictionary it is not clear for example whether aspect should be understood as imperfective / perfective form of a verb or as its meaning. Therefore in the dictionary forms and meaning are separated in a regular way. Imperfective verb form has two meanings: state and configuration of states and events culminating in state. Also perfective verb form has two meanings: event and configuration of states and events culminating in event. These meanings are described by the semantic classifiers, respectively, state and event, state1 and event1. The way of describing language units, mentioned in the article, gives a possibility to present language material (Polish, Bulgarian, Russian in any required order, hence the article’s title.

  15. Characterization of colloidal silica abrasives with different sizes and their chemical–mechanical polishing performance on 4H-SiC (0 0 0 1)

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xiaolei [The State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Pan, Guoshun, E-mail: pangs@tsinghua.edu.cn [The State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Zhou, Yan; Gu, Zhonghua; Gong, Hua; Zou, Chunli [The State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

    2014-07-01

    In this paper, a detailed analysis is presented to characterize the performance of colloidal silica abrasives based slurry with different abrasive sizes on CMP of hexagonal 4H-SiC wafer, and indicates that the abrasive size is an important factor to determine the efficiency of CMP and the final planarization quality of wafer surface. The authors also present a detailed hypothesis to describe the material removal mechanism of 4H-SiC by colloidal silica abrasives during CMP process, and design two groups of experiments to demonstrate the rationality of the hypothesis. Furthermore, the authors put forward some suggestions to optimize the CMP efficiency and planarization quality of 4H-SiC wafer.

  16. Microstructure and Properties of W-Cu Alloys Prepared with Mechanically Activated Powder

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    W-15% Cu (mass fraction) alloys were sintered with mechanically activated powder in order to develop new preparing processes and improve properties of alloys. The microstructures of the activated powder and the sintered alloy were observed. Properties such as density were measured. The results show that through mechanical activation, the particle size of the powder becomes finer to sub-micron or nanometer level, some copper was soluble in tungsten, and high density W-Cu alloys can be obtained by mechanically activated powder for its action to the activation sintering.

  17. New examples of small Polish structures

    OpenAIRE

    Dobrowolski, Jan

    2013-01-01

    We answer some questions from a paper of Krupi\\'nski by giving suitable examples of small Polish structures. First, we present a class of small Polish group structures without generic elements. Next, we construct a first example of a small non-zero-dimensional Polish $G$-group.

  18. An Investigation on a Tin Fixed Abrasive Polishing Pad with Phyllotactic Pattern for Polishing Wafer

    Institute of Scientific and Technical Information of China (English)

    吕玉山; 刘电飞; 寇智慧

    2012-01-01

    In order to improve the polishing ability of polishing pads, a kind of polishing pad with the tin fixed abrasive blocks, which are arranged based on the phyllotaxis theory of biology, was designed and fabricated by the use of electroplating technology, and also its polishing ability for JGS-2 wafer was investigated by polishing experiments. The research resuits show that the phyllotactic parameters of the polishing pad influence the arrangement density of the tin fixed abrasive blocks, the polishing pad with phyllotactic pattern is feasibly fabricated by the use of electroplating technology, and the good polishing result can be obtained by using the polishing pad with pbyllotactic pattern to polish a wafer when the diameter D of the tin fixed abrasive block is between Φ. 3 mm and Φ1. 4 mm, and the phyllotactic coefficient k between 1.0 and 1.1, respectively.

  19. In-situ photopatterning of hydrogel microarrays in polished microchips

    NARCIS (Netherlands)

    Gümüscü, B.; van den Berg, Albert; Eijkel, Jan C.T.

    2015-01-01

    We present a fabrication method which enables simple and eproducible photopatterning of micron- sized hydrogel arrays inside closed microchips. To achieve this, the glass cover of the microchip is thinned by mechanical grinding and polishing. This procedure reduces the spacing between the photomask

  20. In-situ photopatterning of hydrogel microarrays in polished microchips

    NARCIS (Netherlands)

    Gumuscu, Burcu; Berg, van den Albert; Eijkel, Jan C.T.

    2015-01-01

    We present a fabrication method which enables simple and eproducible photopatterning of micron- sized hydrogel arrays inside closed microchips. To achieve this, the glass cover of the microchip is thinned by mechanical grinding and polishing. This procedure reduces the spacing between the photomask

  1. Mechanically loaded ex vivo bone culture system 'Zetos': Systems and culture preparation

    Directory of Open Access Journals (Sweden)

    C M Davies

    2006-04-01

    Full Text Available This paper introduces the culture preparation of ovine, bovine and human cancellous bone cores to be used in an explants model Zetos. The three dimensional (3D bone cores were prepared and evaluated for all three animals. Bone cells in vivo constantly interact with each other, migratory cells, surrounding extracellular matrix (ECM and interstitial fluid in a microenvironment, which continuously responds to various endogenous and exogenous stimuli. The Zetos system was designed to culture and mechanically load viable cancellous bone explants in their near natural microenvironment. This 3D ex vivo system bridges the current gap between in vitro and in vivo methods. One aim of this work was to compare the macro and micro-architecture of ovine, bovine and human cancellous bone tissue in preparation for culture within the Zetos system in order to determine the optimal source of experimental material. A second aim was to optimise the preparations of the bone cores as well as develop techniques involved during tissue maintenance. Bone core response was visualised using histological and immunohistochemical methods. The results demonstrate that cancellous bone explants vary greatly in trabecular density and bone volume depending on species, age and location. Sheep and human samples displayed the greatest variation between bones cores when compared to bovine. Even cores taken from the same animal possessed very different characteristics. The histology demonstrated normal bone and cell structure after the core preparation. Immunohistochemistry results demonstrated antigen retention after preparation methods.

  2. Effects of Chairside Polishing and Brushing on Surface Roughness of Acrylic Denture Base Resins

    Institute of Scientific and Technical Information of China (English)

    Seung-Kyun Kim; Ju-Mi Park; Min-Ho Lee; Jae-Youn Jung; Shipu Li; Xinyu Wang

    2009-01-01

    The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture base resins were compared. Acrylic denture base resins (auto-polymerizing, heat-polymerizing, injected heat-polymerizing resins) were examined after a tungsten carbide bur, and after chairside polishing using 3 polishing kits and pumice. The specimens were subjected to mechanical brushing using a wear tester to simulate 30 000 strokes of brushing. The surface roughness of the acrylic denture base resin specimens was measured using a contact pro-filometer. After the test, the random polished acrylic resins were evaluated by scanning electron mi-croscopy (SEM) and atomic force microscopy (AFM). Acrylic denture base resins polished using the 3 types of polishing kits had a smoother surface than those finished with the tungsten carbide bur (p <0.05). The surface of the resin polished by a TC cutter exceeded the Ra of 0.2 μm (p<0.05). The auto-polymerizing resin showed a significantly higher surface roughness than the heat-polymerizing resin and injected heat-polymerizing resin (p>0.05). In the case of polishing step wise, there was almost no change in surface roughness after brushing (p>0.05).

  3. Polish students at the Académie Julian until 1919

    Directory of Open Access Journals (Sweden)

    Zgórniak, Marek

    2012-08-01

    Full Text Available The subject of the article is the presence of Polish students in the most important private artistic school in Paris in the second half of the 19thcentury. The extant records regarding the atelier for male students made it possible to compile a list of about 165 Polish painters and sculptors studying there in the period from 1880 to 1919. The text presents the criteria used when preparing the list and the diagrams show the fluctuations in registration and the number of Polish artists in particular ateliers in successive years. The observations contained in the article have a summary nature and are illustrated only with selected examples.

  4. Attitudes of Polish Consumers Toward Experiential Marketing

    Directory of Open Access Journals (Sweden)

    Monika Skorek

    2017-01-01

    Full Text Available Purpose: The experience economy is a concept that can be defned as a new way of perceiving the market offer of an enterprise, focusing on the customer experience. Enterprises, both in the production and service industries, are becoming similar to one another on a massive scale, which makes it increasingly diffcult to stand out. The response to this can be to offer the consumer an unforgettable experience related to a product or service provided by a company. Methodology: This study analysed the results of qualitative research on the attitudes and opinions of Polish consumers on experience marketing. Results/fndings: The results showed that participants of the study were prepared to transition from the economy based on products or services to an economy based on experiences at a moderate level. They declared a willingness to participate in experiences offered by companies but at the same time focus on the cost and utility of them

  5. Disturbance induced by surface preparation on instrumented indentation test

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yugang, E-mail: yugang.li@utt.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France); Kanouté, Pascale, E-mail: pascale.kanoute@onera.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France); The French Aerospace Lab (ONERA), DMSM/MCE, 29 avenue de la Division Leclerc-BP 72, F-92322 Chatillon Cedex (France); François, Manuel, E-mail: manuel.francois@utt.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France)

    2015-08-26

    Surface preparation, which may induce considerable sample disturbance, plays an important role in instrumented indentation test (IIT). In this study, the sample disturbance (mainly divided into residual stresses and plastic strain) induced by the surface preparation process of instrumented indentation test specimens were investigated with both experimental tests and numerical simulations. Grazing incidence X-ray diffractions (GIXRD) and uniaxial tensile tests were conducted for characterizing the residual stresses and high plastic strain in the top surface layers of a carefully mechanically polished indentation sample, which, in the present work, is made of commercially pure titanium. Instrumented indentation tests and the corresponding finite element simulations were performed as well. For comparison, a reference sample (carefully mechanically polished & electrolytically polished) which represents the raw material was prepared and tested. Results showed that a careful mechanical polishing procedure can effectively reduce the level of residual stresses induced by this process. However, the high plastic strain in the surface region imposed by the polishing process is significant. The induced plastic strain can affect a depth up to 5 µm, which is deeper than the maximum penetration depth h{sub max} (3 µm) used for the instrumented indentation tests. In the near surface layer (in the range of depth about 350 nm), the plastic strain levels are fairly high. In the very top layer, the plastic strain was even estimated to reach more than 60%. The simultaneous use of indentation tests and numerical simulations showed that the existence of high plastic strain in the surface region will make the load vs depth (P–h) curve shift upwards, the contact hardness (H) increase and the contact stiffness (S) decrease.

  6. 化学机械抛光在光学晶体加工中的应用%Application of chemical mechanical polishing in the processing of optical crystals

    Institute of Scientific and Technical Information of China (English)

    储向峰; 汤丽娟; 董永平; 乔红斌; 朱小华

    2012-01-01

    Intensive investigation on crystal materials accelerated the development of modern science and technology, and the demand for various crystals has been increasing. The surface processing of crystals has become a research focus because ultra-smooth surface is needed in many application fields, In this research, we introduce the development of chemical mechanical polishing of a few kinds of crystals including saphire, LiNbO3, LiB3 O5, CdZnTe, MgO, SiC and InSb, discuss the existing problems and the developing trend in the CMP field of the crystals.%晶体材料的深入研究加速了现代科学技术的发展,其需求量也迅速增加.在很多应用领域要求晶体的表面超光滑,因此晶体表面处理和加工成为目前研究的热点.介绍了几种典型光学晶体(蓝宝石晶体、铌酸锂晶体、三硼酸锂晶体、碲锌镉晶体、氧化镁晶体、碳化硅晶体和锑化铟晶体)化学机械抛光的最新研究成果,并探讨了光学晶体化学机械抛光存在的问题及发展趋势.

  7. High-Q optomechanical circuits made from polished nanocrystalline diamond thin films

    CERN Document Server

    Ummethala, S; Lewes-Malandrakis, G; Brink, D; Nebel, C; Pernice, W H P

    2014-01-01

    We demonstrate integrated optomechanical circuits with high mechanical quality factors prepared from nanocrystalline diamond thin films. Using chemomechanical polishing, the RMS surface roughness of as grown polycrystalline diamond films is reduced below 3nm to allow for the fabrication of high-quality nanophotonic circuits. By integrating free-standing nanomechanical resonators into integrated optical devices, efficient read-out of the thermomechanical motion of diamond resonators is achieved with on-chip Mach-Zehnder interferometers. Mechanical quality factors up to 28,800 are measured for four-fold clamped optomechanical resonators coupled to the evanescent near-field of nanophotonic waveguides. Our platform holds promise for large-scale integration of optomechanical circuits for on-chip metrology and sensing applications.

  8. Development of Application of RE Polishing Materials

    Institute of Scientific and Technical Information of China (English)

    Li Xueshun; Huang Shaodong; Yang Guosheng

    2004-01-01

    The manufacturing method and functions of the RE polishing powder and comparation of the current situation of its production and application home and abroad were introduced.By analyzing the development of the liquid crystal (plate) display, the wide application of the RE polishing powder in the field of the liquid crystal display and predicts the development direction of the market of the RE polishing powder was presented.In addition, the development trends of the RE polishing powder industry and forecasts the application prospect of the RE polishing powder was analyzed.

  9. Effect of polishing on the microleakage of two different restorative materials in primary teeth: An in vitro study

    Directory of Open Access Journals (Sweden)

    Bhagyashree Salunkhe

    2014-01-01

    Full Text Available Aims and objectives: The aim of this in vitro study was to evaluate the effect of polishing on the microleakage of silorane based Composite (Filtek Z350XT and Resin modified GIC (Vitremer restorations in primary teeth. The objectives were to compare the microleakage with and without polishing, and compare the same between the two materials. Materials and Methods: Class V cavities were prepared on 28 retained deciduous anterior teeth, after they were extracted. The prepared teeth were randomly divided into two groups and restored with the respective materials. The restored teeth were then divided into two subgroups (polished and not polished of seven each. Finishing and polishing for the designated subgroup was done using the Shofu polishing kit. The teeth were then thermocycled and subjected to 1% methylene blue dye penetration, and sectioned buccolingually. Microleakage was evaluated by observing degree of dye penetration under a stereomicroscope, and data subjected to statistical analysis. Statistical analysis was done using Mann-Whitney U test. Results: The results showed that polishing decreased the microleakage in Composite restorations (P0.05. Intergroup comparison of the microleakage without polishing was not significant (P>0.05 while the intergroup comparison after polishing was significant (P<0.05, with polished composite showing comparatively less microleakage. Conclusions: The conclusions of the study were that unpolished restorations with both materials did not show any significant difference in the microleakage scores. Composite restorations, after polishing, showed significantly less microleakage in primary teeth, while with Resin Modified GIC restorations, there wasn′t any difference in microleakage, with or without polishing.

  10. Sustained release of doxorubicin from zeolite-magnetite nanocomposites prepared by mechanical activation.

    Science.gov (United States)

    Arruebo, Manuel; Fernández-Pacheco, Rodrigo; Irusta, Silvia; Arbiol, Jordi; Ibarra, M Ricardo; Santamaría, Jesús

    2006-08-28

    Nanocomposites consisting of magnetite and FAU zeolite with a high surface area and adsorption capacity have been prepared by mechanical activation using high-energy milling at room temperature. FTIR results, as well as HRTEM, EFTEM, and XPS measurements, show that the resulting magnetic nanoparticles are covered by a thin aluminosilicate coating. A saturation magnetization as high as 16 emu g(-1) and 94.2 Oe of coercivity were observed for the obtained composites. The main advantages of this synthesis procedure are (i) simplicity of the preparation procedure, (ii) prevention of agglomeration of the magnetite nanoparticles to a large extent, and (iii) absence of free magnetite outside the zeolitic matrix. In addition, in vitro experiments revealed that the nanoparticles prepared were able to store and release substantial amounts of doxorubicin. In view of these advantages, these magnetic nanoparticles can be considered as potential candidates for drug-delivery applications.

  11. Evaluation of the surface roughness in dental ceramics submitted to different finishing and polishing methods.

    Science.gov (United States)

    Vieira, Alex C; Oliveira, Mario C S; Lima, Emilena M C X; Rambob, Isabel; Leite, Mariana

    2013-09-01

    Ceramic restorations have been widely used in dentistry. These restorations often require intraoral adjustment with diamond burs after their cementation causing increasing roughness of the ceramic surface. Consequently some finishing and polishing methods have been used to minimize this occurrence. The aim of this study is to evaluate the roughness of the ceramic surfaces submitted to different finishing and polishing methods. 144 specimens of VITAVM(®)7, VM(®)9 and VM(®)13 (VITA Zahnfabrik) ceramics were fabricated and submitted to grinding using diamond burs. They were then divided into 15 groups (five of each ceramic type). Groups 1, 6 and 11-positive control (Glaze); Groups 2, 7 and 12-negative control (no polishing); Groups 3, 8 and 13-polished with abrasive rubbers (Edenta), felt disc and diamond polishing past; Groups 4, 9 and 14-polished with abrasive rubbers (Shofu), felt disc and diamond polishing past; Groups 5, 10 and 15-polished with aluminum oxide discs (Sof-Lex, 3M-ESPE), felt disc and diamond polishing paste. The roughness of the samples surfaces were measured using the rugosimeter Surfcorder SE 1700 and the data were submitted to statistical analysis using ANOVA and Tukey test at a level of significance of 5 %. There was statistically significance difference between the positive control groups and the other groups in all the ceramic types. Mechanical finishing and polishing methods were not able to provide a surface as smooth as the glazed surface for the tested ceramics. To assist dental practitioners to select the best finishing and polishing methods for the final adjustment of the ceramic restorations.

  12. Preparation and mechanism study of bulk pure rare-earth metals with amorphous and nanocrystalline structures

    Institute of Scientific and Technical Information of China (English)

    LI ErDong; SONG XiaoYan; ZHANG JiuXing; LU NianDuan

    2007-01-01

    The preparation and the mechanism study of bulk pure rare-earth metals with amorphous and nanocrystalline structures, which were produced by spark plasma sintering (SPS), were carried out in this paper. With different processing parameters, the amorphous, two phases of amorphous and nanocrystalline, and complete nanocrystalline microstructures have been obtained. The nano-grain sizes in the bulk nanocrystalline materials are found smaller than the original powder particles sizes, which may change the conventional viewpoint that the grains in the sintered bulk are generally coarser than the raw powder particles. The technique developed in the present work can be extended to the preparation of many other nano bulk metal materials, and thus enables the studies of the nano-size effects on the physical, chemical and mechanical properties of bulk nano materials.

  13. Preparation, characterization and mechanical properties of rare-earth-based nanocomposites

    Directory of Open Access Journals (Sweden)

    Musbah S.S.

    2012-01-01

    Full Text Available This study reports research related to different preparation methods and characterization of polymer nanocomposites for optical applications. The Eu-ion doped Gd2O3 nanophosphor powder with different nanoparticle content was embedded in the matrix of PMMA. Preparation was carried out by mixing molding (bulk, electrospinning (nanofibers and solution casting (thin films with neat particles and particles coated with AMEO silane. Among the pros and cons for proposed methods, the mixing molding enables to avoid solvent use while the best deagglomeration and nanoparticle distribution is gained using the electrospinning method. The results of dynamic mechanical analysis (DMA and nanoindentation revealed that the storage modulus of the composites was higher than that of pure PMMA and increased with nanophosphor content. Surface modification of particles improved the mechanical properties of nanocomposites.

  14. Strategy for development of the Polish electricity sector

    Energy Technology Data Exchange (ETDEWEB)

    Dybowski, J. [Polish Power Grid Co., Warsaw (Poland)

    1995-12-01

    This paper represents the strategy for development of the Polish Electricity Sector dealing with specific problems which are common for all of East Central Europe. In 1990 Poland adopted a restructuring program for the entire energy sector. Very ambitious plans were changed several times but still the main direction of change was preserved. The most difficult period of transformation is featured by several contradictions which have to be balanced. Electricity prices should increase in order to cover the modernization and development program but the society is not able to take this burden in such a short time. Furthermore the new environment protection standards force the growth of capital investment program which sooner or later has to be transferred through the electricity prices. New economic mechanisms have to be introduced to the electricity sector to replace the old ones noneffective, centrally planned. This process has to follow slow management changes. Also, introduction of new electricity market is limited by those constraints. However, this process of change would not be possible without parallel governmental initiation like preparation of new energy law and regulatory frames.

  15. Material Removal Model Considering Influence of Curvature Radius in Bonnet Polishing Convex Surface

    Institute of Scientific and Technical Information of China (English)

    SONG Jianfeng; YAO Yingxue

    2015-01-01

    The bonnet tool polishing is a novel, advanced and ultra-precise polishing process, by which the freeform surface can be polished. However, during the past few years, not only the key technology of calculating the dwell time and controlling the surface form in the bonnet polishing has been little reported so far, but also little attention has been paid to research the material removal function of the convex surface based on the geometry model considering the influence of the curvature radius. Firstly in this paper, for realizing the control of the freeform surface automatically by the bonnet polishing, on the basis of the simplified geometric model of convex surface, the calculation expression of the polishing contact spot on the convex surface considering the influence of the curvature radius is deduced, and the calculation model of the pressure distribution considering the influence of the curvature radius on the convex surface is derived by the coordinate transformation. Then the velocity distribution model is built in the bonnet polishing the convex surface. On the basis of the above research and the semi-experimental modified Preston equation obtained from the combination method of experimental and theoretical derivation, the material removal model of the convex surface considering the influence of the curvature radius in the bonnet polishing is established. Finally, the validity of the model through the simulation method has been validated. This research presents an effective prediction model and the calculation method of material removal for convex surface in bonnet polishing and prepares for the bonnet polishing the free surface numerically and automatically.

  16. Preparation and Mechanical Performance of Rare Earth-Containing Composite Elastomer

    Institute of Scientific and Technical Information of China (English)

    邱关明; 周兰香; 张明; 中北里志; 井上真一; 冈本弘

    2001-01-01

    Rare earth-containing PSBR sheet was prepared by reaction of rare earth alkoxide with quaternary ammonium salt of pyridine modified SBR (PSBR) latex, and then it was blended with natural rubber (NR) to produce rare earth-containing composite elastomer. It is found that mechanical performance can be improved remarkably. Analyzed by infrared spectrometry (IR), differential scanning calorimetry (DSC) and cross-linking densitometry, the relationship between structure and performance was discussed.

  17. Preparation and thermal decomposition mechanism of Mg,Al-hydrotalcite nano-crystals with titania doping

    Institute of Scientific and Technical Information of China (English)

    REN Qing-li; LUO Qiang

    2006-01-01

    The highly pure nano-crystal Mg,Al-hydrotalcite with titania doping was synthesized by one-step liquid reaction method at atmospheric pressure. The preparation of the Mg,Al-hydrotalcite nano-crystal after doping titania was investigated according to the results of XRD,TEM,IR and DSC. Moreover,based on the DSC test results,the thermal mechanism functions of the Mg,Al-hydrotalcite with titania doping were studied after calculation and comparison.

  18. Phase Development and Crystallization Kinetics of NiTi Prepared by Mechanical Alloying

    Institute of Scientific and Technical Information of China (English)

    Xunyong JIANG; Xueping GAO; Deying SONG

    2003-01-01

    NiTi alloy is produced by mechanical alloying(MA). It becomes amorphous after milling for enough time, such as 100 h in this paper. DSC measurement shows that the crystallization temperature is 676 K for the amorphous powder. Activation energy of crystallization is 199.98 kJ/mol for MA powder, which is lower than that of amorphous prepared by magnetron sputtering.Avrami parameter of crystallization is 1.07.

  19. Preparation and Characterization of Chitosan/Poly(Vinyl Alcohol Blended Films: Mechanical, Thermal and Surface Investigations

    Directory of Open Access Journals (Sweden)

    Esam A. El-Hefian

    2011-01-01

    Full Text Available In this study, blends of chitosan (CS and polyvinyl alcohol (PVA (CS/PVA having various proportions were prepared and characterized by universal mechanical tester, the differential scanning calorimetry (DSC and contact angle measurements. Studying the mechanical properties of the films showed that blending improved the tensile strength, which increased with increasing PVA content up to 40% while the elongation% at break of the blends was decreased compared to that of the pure components. The obtained results of DSC suggested that some interaction between chitosan and PVA mostly took place. Static water contact angle measurements showed an improvement in the wettability of the obtained films.

  20. Microstructure and Mechanical Properties of FeAl Intermetallics Prepared by Mechanical Alloying and Hot-Pressing

    Institute of Scientific and Technical Information of China (English)

    SONG Haixia; WU Yunxin; TANG Chuan'an; YUAN Shuai; GONG Qianming; LIANG Ji

    2009-01-01

    FeAl intermetallics were prepared by mechanical alloying and vacuum hot-pressing. The Fe-48 at.% Al powder was ball-milled for 3-12 h, producing a solid solution structure of Fe (Al) with trace Al (Fe). Subsequent vacuum annealing or hot-pressing introduced phase transformations into the FeAl (B2) inter-metallics and Al2O3 inclusions. The hot-pressed FeAl intermetallics possess a high flexural strength of 831 Mpa and a fairly good strain at break of 3.2%. The results show that the addition of 0.5 at,% B reduces the peak temperature for hot-pressing from 1180℃ to 1100℃, and increases the density of the compacts from 95% to 96.3%, but results in no significant improvement in the mechanical properties.

  1. Energy savings in Polish buildings

    Energy Technology Data Exchange (ETDEWEB)

    Markel, L.C.; Gula, A.; Reeves, G.

    1995-12-31

    A demonstration of low-cost insulation and weatherization techniques was a part of phase 1 of the Krakow Clean Fossil Fuels and Energy Efficient Project. The objectives were to identify a cost-effective set of measures to reduce energy used for space heating, determine how much energy could be saved, and foster widespread implementation of those measures. The demonstration project focused on 4 11-story buildings in a Krakow housing cooperative. Energy savings of over 20% were obtained. Most important, the procedures and materials implemented in the demonstration project have been adapted to Polish conditions and applied to other housing cooperatives, schools, and hospitals. Additional projects are being planned, in Krakow and other cities, under the direction of FEWE-Krakow, the Polish Energie Cities Network, and Biuro Rozwoju Krakowa.

  2. Polishing compound for plastic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Stowell, M.S.

    1991-01-01

    This invention is comprised of a polishing compound for plastic materials. The compound includes approximately by approximately by weight 25 to 80 parts at least one petroleum distillate lubricant, 1 to 12 parts mineral spirits, 50 to 155 parts abrasive paste, and 15 to 60 parts water. Preferably, the compound includes approximately 37 to 42 parts at least one petroleum distillate lubricant, up to 8 parts mineral spirits, 95 to 110 parts abrasive paste, and 50 to 55 parts water. The proportions of the ingredients are varied in accordance with the particular application. The compound is used on PLEXIGLAS{trademark}, LEXAN{trademark}, LUCITE{trademark}, polyvinyl chloride (PVC), and similar plastic materials whenever a smooth, clear polished surface is desired.

  3. Stress polishing demonstrator for ELT M1 segments and industrialization

    Science.gov (United States)

    Hugot, Emmanuel; Bernard, Anaïs.; Laslandes, Marie; Floriot, Johan; Dufour, Thibaut; Fappani, Denis; Combes, Jean Marc; Ferrari, Marc

    2014-07-01

    After two years of research and development under ESO support, LAM and Thales SESO present the results of their experiment for the fast and accurate polishing under stress of ELT 1.5 meter segments as well as the industrialization approach for mass production. Based on stress polishing, this manufacturing method requires the conception of a warping harness able to generate extremely accurate bending of the optical surface of the segments during the polishing. The conception of the warping harness is based on finite element analysis and allowed a fine tuning of each geometrical parameter of the system in order to fit an error budget of 25nm RMS over 300μm of bending peak to valley. The optimisation approach uses the simulated influence functions to extract the system eigenmodes and characterise the performance. The same approach is used for the full characterisation of the system itself. The warping harness has been manufactured, integrated and assembled with the Zerodur 1.5 meter segment on the LAM 2.5meter POLARIS polishing facility. The experiment consists in a cross check of optical and mechanical measurements of the mirrors bending in order to develop a blind process, ie to bypass the optical measurement during the final industrial process. This article describes the optical and mechanical measurements, the influence functions and eigenmodes of the system and the full performance characterisation of the warping harness.

  4. 19th Polish Control Conference

    CERN Document Server

    Kacprzyk, Janusz; Oprzędkiewicz, Krzysztof; Skruch, Paweł

    2017-01-01

    This volume contains the proceedings of the KKA 2017 – the 19th Polish Control Conference, organized by the Department of Automatics and Biomedical Engineering, AGH University of Science and Technology in Kraków, Poland on June 18–21, 2017, under the auspices of the Committee on Automatic Control and Robotics of the Polish Academy of Sciences, and the Commission for Engineering Sciences of the Polish Academy of Arts and Sciences. Part 1 deals with general issues of modeling and control, notably flow modeling and control, sliding mode, predictive, dual, etc. control. In turn, Part 2 focuses on optimization, estimation and prediction for control. Part 3 is concerned with autonomous vehicles, while Part 4 addresses applications. Part 5 discusses computer methods in control, and Part 6 examines fractional order calculus in the modeling and control of dynamic systems. Part 7 focuses on modern robotics. Part 8 deals with modeling and identification, while Part 9 deals with problems related to security, fault ...

  5. ZERODUR for stress mirror polishing

    Science.gov (United States)

    Jedamzik, Ralf; Kunisch, Clemens; Westerhoff, Thomas

    2011-09-01

    Stress mirror polishing is considered as one of several polishing technologies for the generation of the aspherical shaped primary mirror segments of the thirty meter telescope (TMT). For stress mirror polishing it is essential to precisely know the elastic response of glass ceramic substrate materials under a given deformation load. In the past it was experimentally shown that glass ceramics do not respond instantaneously to loading and unloading conditions, this effect was called "delayed elasticity." Recently SCHOTT has shown that it is possible to use a model to predict the characteristic thermal expansion behaviour of individual ZERODUR® batches for a given temperature profile. A similar approach will be used to predict the delayed elastic behavior of ZERODUR® under time dependent loads. In this presentation the delayed elasticity effect of ZERODUR® is reviewed. The delayed elastic response of the material to load conditions is shown and discussed. First results of a model approach based on experimental results and tools that have been built up for the modelling of the delayed elasticity effect of ZERODUR® will be presented.

  6. Preparation and thermal-mechanical characterization of nanoclay-unsaturated polyester composites.

    Science.gov (United States)

    Calvo, S; Prolongo, M G; Salom, C; Masegosa, R M

    2010-04-01

    Recently polymer nanocomposites have attracted great interest as much as in industry as in research laboratories, due to they often show remarkable improvement in their mechanical and thermal properties when are compared with the virgin polymers. Among nanocomposites, nanoclay-reinforced polymers have been widely studied, specifically, those formed by a thermosetting polymer matrix, like unsaturated polyester crosslinked resin reinforced with layered silicates, like montmorillonite. In this work we have prepared nanocomposites formed by an isophtalic unsaturated polyester crosslinked resin (UP) reinforced with different contents (2-10 wt%) of organic modified montmorillonite (OMMT). The UP/OMMT nanocomposites have been prepared following different procedures and the structural characterization has been carried out by using X-ray diffraction (XRD). In all the cases an increase of the d-spacing between layers of the OMMT has been detected. The objective of this study is to analyze the thermal and mechanical behaviour of nanocomposites. For all of the reinforced systems, the glass transition temperatures values, Tg, obtained by differential scanning calorimetry (DSC) and dynamic-mechanical thermal analysis, (DMTA) are higher than the corresponding ones to neat UP. On the other hand, the OMMTP mechanical behaviour has been evaluated by DMTA and by tensile tests. Both techniques reveal an increase in Young modulus, however, a decrease of the tensile strength is observed in all the reinforced systems.

  7. Preparation, Characterization, and Enhanced Thermal and Mechanical Properties of Epoxy-Titania Composites

    Science.gov (United States)

    Rubab, Zakya; Siddiqi, Humaira M.; Saeed, Shaukat

    2014-01-01

    This paper presents the synthesis and thermal and mechanical properties of epoxy-titania composites. First, submicron titania particles are prepared via surfactant-free sol-gel method using TiCl4 as precursor. These particles are subsequently used as inorganic fillers (or reinforcement) for thermally cured epoxy polymers. Epoxy-titania composites are prepared via mechanical mixing of titania particles with liquid epoxy resin and subsequently curing the mixture with an aliphatic diamine. The amount of titania particles integrated into epoxy matrix is varied between 2.5 and 10.0 wt.% to investigate the effect of sub-micron titania particles on thermal and mechanical properties of epoxy-titania composites. These composites are characterized by X-ray photoelectron (XPS) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric (TG), and mechanical analyses. It is found that sub-micron titania particles significantly enhance the glass transition temperature (>6.7%), thermal oxidative stability (>12.0%), tensile strength (>21.8%), and Young's modulus (>16.8%) of epoxy polymers. Epoxy-titania composites with 5.0 wt.% sub-micron titania particles perform best at elevated temperatures as well as under high stress. PMID:24578638

  8. Microstructural and mechanical characteristics of porous iron prepared by powder metallurgy.

    Science.gov (United States)

    Capek, Jaroslav; Vojtěch, Dalibor

    2014-10-01

    The demand for porous biodegradable load-bearing implants has been increasing recently. Based on investigations of biodegradable stents, porous iron may be a suitable material for such applications. In this study, we prepared porous iron samples with porosities of 34-51 vol.% by powder metallurgy using ammonium bicarbonate as a space-holder material. We studied sample microstructure (SEM-EDX and XRD), flexural and compressive behaviors (universal loading machine) and hardness HV5 (hardness tester) of the prepared samples. Sample porosity increased with the amount of spacer in the initial mixtures. Only the pore surfaces had insignificant oxidation and no other contamination was observed. Increasing porosity decreased the mechanical properties of the samples; although, the properties were still comparable with human bone and higher than those of porous non-metallic biomaterials and porous magnesium prepared in a similar way. Based on these results, powder metallurgy appears to be a suitable method for the preparation of porous iron for orthopedic applications.

  9. Mechanical, dielectric and optical assessment of glass composites prepared using milling technique

    Indian Academy of Sciences (India)

    Gurbinder Kaur; G Pickrell; V Kumar; O P Pandey; K Singh; S K Arya

    2015-08-01

    In the present investigation, mechanical and spectroscopic properties of glass composites have been investigated. The glass composites have been prepared by the milling technique instead of using any filler particle. Due to the presence of different alkaline earth modifiers in composites, marked difference in their strength and optical properties is observed. The band gap, Urbach energy and the extinction coefficient of the glass composites have been calculated using UV–visible spectroscopy. Moreover, the real and imaginary dielectric constants have also been calculated for all the composites in addition to the Weibull statistics and cumulative probability of failure. The results have been discussed in light of comparison between the glass composites and the individual glasses. The mechanical and optical properties indicate marked effect on the mechanical strength, band gap and Urbach energy for glass composites as compared with the individual glasses.

  10. Mechanical Properties and Microstructure of Portland Cement Concrete Prepared with Coral Reef Sand

    Institute of Scientific and Technical Information of China (English)

    WANG Qiankun; LI Peng; TIAN Yapo; CHEN Wei; SU Chunyi

    2016-01-01

    The feasibility of using coral reef sand (CRS) in Portland cement concrete is investigated by testing the mechanical property and microstructure of concrete. The composition, structure and properties of the CRS are analyzed. Mechanical properties and microstructure of concrete with CRS are studied and compared to concrete with natural river sand. The relationship between the microstructure and performance of CRS concrete is established. The CRS has a porous surface with high water intake capacity, which contributes to the mechanical properties of concrete. The interfacial transition zone between the cement paste and CRS is densiifed compared to normal concrete with river sand. Hydration products form in the pore space of CRS and interlock with the matrix of cement paste, which increases the strength. The total porosity of concrete prepared with CRS is higher than that with natural sand. The main difference in pore size distribution is the fraction of ifne pores in the range of 100 nm.

  11. MWCNTs/Cellulose Hydrogels Prepared from NaOH/Urea Aqueous Solution with Improved Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Yingpu Zhang

    2015-01-01

    Full Text Available Novel high strength composite hydrogels were designed and synthesized by introducing multiwalled carbon nanotubes (MWCNTs into cellulose/NaOH/urea aqueous solution and then cross-linked by epichlorohydrin. MWCNTs were used to modify the matrix of cellulose. The structure and morphology of the hydrogels were characterized by Fourier transform infrared (FT-IR spectroscopy, high resolution transmission electron microscopy (HR-TEM, and scanning electron microscopy (SEM. The results from swelling testing revealed that the equilibrium swelling ratio of hydrogels decreased with the increment of MWCNTs content. Thermogravimetric analysis (TGA and dynamic mechanical analysis (DMA results demonstrated that the introduction of MWCNT into cellulose hydrogel networks remarkably improved both thermal and mechanical properties of the composite hydrogels. The preparation of MWCNTs modifiedcellulose-based composites with improved mechanical properties was the first important step towards the development of advanced functional materials.

  12. The effects of different polishing techniques on the staining resistance of CAD/CAM resin-ceramics

    Science.gov (United States)

    Demirci, Tevfik; Demirci, Gamze; Sagsoz, Nurdan Polat; Yildiz, Mehmet

    2016-01-01

    PURPOSE The purposes of this study were to evaluate the staining resistance of CAD/CAM resin-ceramics polished with different techniques and to determine the effectiveness of the polishing techniques on resin-ceramics, comparing it with that of a glazed glass-ceramic. MATERIALS AND METHODS Four different CAD/CAM ceramics (feldspathic ceramic: C-CEREC Blocs, (SIRONA) and three resin-ceramics: L-Lava Ultimate, (3M ESPE), E-Enamic, (VITA) and CS-CeraSmart, (GC)) and one light cure composite resin: ME-Clearfil Majesty Esthetic (Kuraray) were used. Only C samples were glazed (gl). Other restorations were divided into four groups according to the polishing technique: nonpolished control group (c), a group polished with light cure liquid polish (Biscover LV BISCO) (bb), a group polished with ceramic polishing kit (Diapol, EVE) (cd), and a group polished with composite polishing kit (Clearfil Twist Dia, Kuraray) (kc). Glazed C samples and the polished samples were further divided into four subgroups and immersed into different solutions: distilled water, tea, coffee, and fermented black carrot juice. Eight samples (8 × 8 × 1 mm) were prepared for each subgroup. According to CIELab system, four color measurements were made: before immersion, immersion after 1 day, after 1 week, and after 1 month. Data were analyzed with repeated measures of ANOVA (α=.05). RESULTS The highest staining resistance was found in gl samples. There was no difference among gl, kc and cd (P>.05). Staining resistance of gl was significantly higher than that of bb (P<.05). Staining resistances of E and CS were significantly higher than those of L and ME (P<.05). CONCLUSION Ceramic and composite polishing kits can be used for resin ceramics as a counterpart of glazing procedure used for full ceramic materials. Liquid polish has limited indications for resin ceramics. PMID:28018558

  13. Method of surface preparation of niobium

    Science.gov (United States)

    Srinivasan-Rao, Triveni; Schill, John F.

    2003-01-01

    The present invention is for a method of preparing a surface of niobium. The preparation method includes polishing, cleaning, baking and irradiating the niobium surface whereby the resulting niobium surface has a high quantum efficiency.

  14. Effects of different polishing techniques on the surface roughness of dental porcelains

    Directory of Open Access Journals (Sweden)

    Işil Sarikaya

    2010-02-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate the effects of different polishing techniques on the surface roughness of dental porcelains. MATERIAL AND METHODS: Fifty-five cylindirical specimens (15x2 mm were prepared for each feldspathic (Vita VMK 95, Ceramco III and low-fusing dental porcelain (Matchmaker. Fifty-five specimens of machinable feldspathic porcelain blocks (Vitablocs Mark II, (12x14x18 mm were cut into 2-mm-thick slices (12x14 mm with low speed saw. The prepared specimens were divided into 11 groups (n=5 representing different polishing techniques including control ((C no surface treatment, glaze (G and other 9 groups that were finished and polished with polishing discs (Sof-Lex (Sl, two porcelain polishing kits (NTI (Pk, Dialite II (Di, a diamond polishing paste (Sparkle (Sp, a zirconium silicate based cleaning and polishing prophy paste (Zircate (Zr, an aluminum oxide polishing paste (Prisma Gloss (Pg, and combinations of them. The surface roughness of all groups was measured with a profilometer. The data were analyzed with a 2-way analysis of variance, and the mean values were compared by the Tukey Honestly Significant Difference test (a=0.05. RESULTS: For all porcelain material groups, the lowest Ra values were observed in Group Gl, Group Sl, Group Pk, and Group Di, which were not significantly different from each other (p>0.05.When comparing the 4 different porcelain materials, the machinable feldspathic porcelain block group (Mark II demonstrated statistically significantly less Ra values than the other porcelain materials tested (p<0.05. No significant difference was observed between the VMK 95 and Ceramco III porcelain groups (p=0.919, also these groups demonstrated the highest Ra values. CONCLUSION: Subjected to surface roughness, the surfaces obtained with polishing and/or cleaning-prophy paste materials used alone were rougher compared to the surfaces finished using Sof-lex, Dialite, and NTI polishing kit

  15. Preparing high-density polymer brushes by mechanically assisted polymer assembly (MAPA)

    Science.gov (United States)

    Wu, Tao; Efimenko, Kirill; Genzer, Jan

    2001-03-01

    We introduce a novel method of modifying the surface properties of materials. This technique, called MAPA (="mechanically assisted polymer assembly"), is based on: 1) chemically attaching polymerization initiators to the surface of an elastomeric network that has been previously stretched by a certain length, Δx, and 2) growing end-anchored macromolecules using surface initiated ("grafting from") atom transfer living radical polymerization. After the polymerization, the strain is removed from the substrate, which returns to its original size causing the grafted macromolecules to stretch away from the substrate and form a dense polymer brush. We demonstrate the feasibility of the MAPA method by preparing high-density polymer brushes of poly(acryl amide), PAAm. We show that, as expected, the grafting density of the PAAm brushes can be increased by increasing Δx. We demonstrate that polymer brushes with extremely high grafting densities can be successfully prepared by MAPA.

  16. Innovative Fly Ash Geopolymer-Epoxy Composites: Preparation, Microstructure and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Giuseppina Roviello

    2016-06-01

    Full Text Available The preparation and characterization of composite materials based on geopolymers obtained from fly ash and epoxy resins are reported for the first time. These materials have been prepared through a synthetic method based on the concurrent reticulation of the organic and inorganic components that allows the formation of hydrogen bonding between the phases, ensuring a very high compatibility between them. These new composites show significantly improved mechanical properties if compared to neat geopolymers with the same composition and comparable performances in respect to analogous geopolymer-based composites obtained starting from more expensive raw material such as metakaolin. The positive combination of an easy synthetic approach with the use of industrial by-products has allowed producing novel low cost aluminosilicate binders that, thanks to their thixotropicity and good adhesion against materials commonly used in building constructions, could be used within the field of sustainable building.

  17. Innovative Fly Ash Geopolymer-Epoxy Composites: Preparation, Microstructure and Mechanical Properties.

    Science.gov (United States)

    Roviello, Giuseppina; Ricciotti, Laura; Tarallo, Oreste; Ferone, Claudio; Colangelo, Francesco; Roviello, Valentina; Cioffi, Raffaele

    2016-06-09

    The preparation and characterization of composite materials based on geopolymers obtained from fly ash and epoxy resins are reported for the first time. These materials have been prepared through a synthetic method based on the concurrent reticulation of the organic and inorganic components that allows the formation of hydrogen bonding between the phases, ensuring a very high compatibility between them. These new composites show significantly improved mechanical properties if compared to neat geopolymers with the same composition and comparable performances in respect to analogous geopolymer-based composites obtained starting from more expensive raw material such as metakaolin. The positive combination of an easy synthetic approach with the use of industrial by-products has allowed producing novel low cost aluminosilicate binders that, thanks to their thixotropicity and good adhesion against materials commonly used in building constructions, could be used within the field of sustainable building.

  18. Study on reaction mechanism of low temperature preparation of nanocrystalline LaCoO3-λ

    Institute of Scientific and Technical Information of China (English)

    SHEN Haiyun; YANG Qiuhua; LI Ning

    2008-01-01

    Perovskite-type oxide nanocrystalline LaCoO3-λ was prepared using the citrate method.The structure and morphology of the sam-pies were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM).The intermediate products were analyzed by thermal gravimetric and differential thermal analysis (TG-DTA) technology.The results showed that nanocrystaUine LaCoO3-λwith a granula of 30-50 nm had a cubic perovskite structure.The reaction mechanism of low temperature preparation was suggested as fol-lows:the metal complex was first formed by the combination of metal ion and citric acid;and then it decomposed into an aconitie acid com-plex, followed by an oxycarbonate,and finally a perovskite-type oxide.

  19. Innovative Fly Ash Geopolymer-Epoxy Composites: Preparation, Microstructure and Mechanical Properties

    Science.gov (United States)

    Roviello, Giuseppina; Ricciotti, Laura; Tarallo, Oreste; Ferone, Claudio; Colangelo, Francesco; Roviello, Valentina; Cioffi, Raffaele

    2016-01-01

    The preparation and characterization of composite materials based on geopolymers obtained from fly ash and epoxy resins are reported for the first time. These materials have been prepared through a synthetic method based on the concurrent reticulation of the organic and inorganic components that allows the formation of hydrogen bonding between the phases, ensuring a very high compatibility between them. These new composites show significantly improved mechanical properties if compared to neat geopolymers with the same composition and comparable performances in respect to analogous geopolymer-based composites obtained starting from more expensive raw material such as metakaolin. The positive combination of an easy synthetic approach with the use of industrial by-products has allowed producing novel low cost aluminosilicate binders that, thanks to their thixotropicity and good adhesion against materials commonly used in building constructions, could be used within the field of sustainable building. PMID:28773582

  20. An Overview of Polish Martial Arts

    Directory of Open Access Journals (Sweden)

    Wojciech J. Cynarski

    2012-07-01

    Full Text Available The purpose of this study is to explain the revival of Polish martial arts from the perspectives of cultural sociology, the sciences of physical culture, and the humanistic theory of martial arts. The Polish Martial Arts (Polskie Sztuki Walki are a subject still requiring serious scientific examination, even in Poland. There are few works concerning the history of Polish weapons, and most only describe techniques for wielding specific types of edged weapons. Nevertheless, there is a large group of enthusiasts trying to restore and cultivate the old Polish tradition, a tradition with heavy emphasis on the art of fencing. The author knows many of the people and facts presented here, from personal observation and from direct participation in these arts. As a disciple of the late Master Yoshio Sugino (10th-dan Kobudo Katori Shinto-ryu, he fought against the Polish saber champion, and he has taken part in joint exhibitions of Polish and Japanese fencing.

  1. Polish-Chinese Economic Relations after Polish Accession to European Union

    OpenAIRE

    Kalinowska, Izabela

    2011-01-01

    The aim of the article is to analize polish-chinese economic relations after polish accession to the European Union structures. Studies carried out in the first part of the article concern trade rates between the two countries. Results show that polish import from China exceed export. The negative trends persist for many years and are continually deepening. From the geographical side, polish import from China flows mainly from the east coast part of China including Peking an...

  2. Effect of filler type and polishing on the discoloration of composite resin artificial teeth.

    Science.gov (United States)

    Imamura, Soichiro; Takahashi, Hidekazu; Hayakawa, Iwao; Loyaga-Rendon, Paola G; Minakuchi, Shunsuke

    2008-11-01

    In this study, the effects of filler type and polishing on the discoloration of composite resin artificial teeth were examined. Four types of experimental resins were prepared: one was a matrix resin, while the others were composite resins containing three different types of fillers (nano-sized silica filler with or without silanization, and prepolymerized filler). Specimens were immersed in distilled water, coffee, red wine, or curry. Color change after immersion was measured using a colorimeter. Color difference values (delta E) and changes in translucency parameter (delta TP) were statistically analyzed using three-way ANOVA and Tukey's comparison. On the influence of the polishing factor, statistically significant differences were neither observed in delta E nor delta TP between polished and non-polished tooth surfaces. On the contrary, the influences of filler type and discoloration medium, and their interaction thereof, were significant. With unsilanized filler, the delta E value of composite resin artificial teeth was significantly increased.

  3. Polish in the light of grammaticalization theory

    Directory of Open Access Journals (Sweden)

    Björn Hansen

    2015-11-01

    Full Text Available Polish in the light of grammaticalization theory The paper is concerned with grammaticalization, a type of language change whereby lexical items, in specifi contexts, come to serve grammatical functions, and grammatical items acquire new grammatical functions. The aim is twofold: to shed light at the main properties of grammaticalization, and to demonstrate its applicability to Polish data. Some prominent examples in Polish are discussed: the grammaticalization of modals, imperative and avertive constructions. The paper closes with a non-exhaustive list of leads for further research into grammaticalization in Polish.

  4. Effect of polishing techniques and time on surface roughness, hardness and microleakage of resin composite restorations.

    Science.gov (United States)

    Venturini, Daniela; Cenci, Maximiliano Sérgio; Demarco, Flávio Fernando; Camacho, Guilherme Brião; Powers, John M

    2006-01-01

    This study evaluated the effects of immediate and delayed polishing on the surface roughness, microhardness and microleakage of a microfilled (Filtek A110) and a hybrid (Filtek Z250) resin composite. Standardized preparations were made on the buccal surfaces of 256 bovine teeth; half were restored with each composite (128 teeth per composite). Immediately after curing, gross finishing was carried out with #280 sandpaper. The specimens restored with each composite were divided into two subgroups. The first group (IM) was polished immediately after gross finishing, using three different systems (n=16): Sequence A, Sof-Lex; Sequence B, Flexicups and Sequence C, Flexicups + Jiffy Polishing Brush + Flexibuffs. The specimens were then stored for three weeks in saline 37 degrees C. The second group (DE) was stored for two weeks, then polished with the same systems and stored for one additional week. The controls (n=16) were analyzed without polishing. Five readings per specimen were taken for surface roughness and hardness. After immersion in basic fuchsin, microleakage was evaluated (40x) using standardized scores. The data were analyzed at a significance level of 0.05, with analysis of variance and an SNK test (surface roughness and microhardness) or with Kruskal-Wallis (microleakage). In both composites, only for the sequential technique was there an influence of delay in polishing on roughness (Ra). Flexicups exhibited the highest Ra of the three systems. The IM and Filtek Z-250 groups showed higher hardness than the DE and Filtek A-110 groups, respectively. Dentin margins showed more leakage than enamel margins; the sequential technique produced more leakage than the other techniques in dentin (pcomposite, time and polishing technique--had a significant influence on surface roughness, hardness and microleakage. Generally, immediate polishing produced no detrimental effect compared to delayed polishing.

  5. Applicability of chemical vapour polishing of additive manufactured parts to meet production-quality

    DEFF Research Database (Denmark)

    Pedersen, D. B.; Hansen, H. N.; Nielsen, J. S.

    2014-01-01

    The Fused Deposition Modelling (FDM) method is the most rapidly growing Additive Manufacturing (AM) method[1]. FDM employs a 2.5D deposition scheme which induce a step-ladder shaped surface definition [2], with seams of the individual layers clearly visible[3]. This paper investigate to which...... extend chemical vapour polishing can be applied to eliminate the layered surfaces from FDM, so that a polished surface quality is obtained. It is quantified to what extend parts can be vapour polished and how geometrical and mechanical properties alter. The fundamental question is whether the surfaces...

  6. Enhanced properties of an AA7075 based metal matrix composite prepared using mechanical alloying

    OpenAIRE

    Nazik, C.; Tarakcioglu, N.; Canakci, A.; Varol, T.; , S. Ozkaya

    2014-01-01

    In this study, firstly, AA7075 metal powder which average particle size 43.9 µm were manufactured by using gas atomization method. Thereafter with mechanical alloying method which powder metallurgy manufacturing methods, 10% B4C particle reinforcements that average particle size of 49.5 µm by participating into AA7075 metal matrix composite powder mixtures were prepared. They were milled for different durations (0-8 hrs) in a high energy planetary ball mill. From these milled powders; 550°C a...

  7. Furnace bottom rise mechanism in preparation of Al-Si alloys by electrothermal process

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The experiments of preparation of Al-Si alloys by electrothermal process were carried out respectively in 20 kW, 100 kW and 1 800 kW DC arc furnaces. The mechanism of furnace bottom rise was studied.It was found that the bottom rise can be divided into three types, including the low bottom temperature, abnormal reducing reaction and carbide deposition. The furnace bottom rise is related to the carbon ratio of the briquet, the heating speed of the briquet and the parameters and operation of furnace.

  8. Physical, mechanical, and tribological properties of quasicrystalline Al-Cu-Fe coatings prepared by plasma spraying

    Science.gov (United States)

    Lepeshev, A. A.; Rozhkova, E. A.; Karpov, I. V.; Ushakov, A. V.; Fedorov, L. Yu.

    2013-12-01

    The physical, mechanical, and tribological properties of quasicrystalline coatings based on the Al65Cu23Fe12 alloy prepared by plasma spraying have been investigated. The specific features of the phase formation due to the competitive interactions of the icosahedral ψ and cubic β phases have been elucidated. A correlation between the microhardness and the content of the icosahedral phase in the coating has been determined. The decisive role of the quasicrystalline phase in the formation of high tribological characteristics of the coatings has been revealed and tested.

  9. Surface roughness of composite resins after finishing and polishing

    Directory of Open Access Journals (Sweden)

    Nagem Filho Halim

    2003-01-01

    Full Text Available This study evaluated the effect of surface finishing methods on the average surface roughness of resin composites. Seven composites and two polishing systems were used. One hundred and twenty-six conical specimens of each material were prepared in stainless steel molds against a polyester strip. Forty-two of them remained intact and were used as controls. Each half of the remaining samples was polished with either diamond burs or diamond burs + aluminum oxide discs. The results showed no statistical difference in average surface roughness (Ra, mm between the polyester strip and aluminum oxide discs (p>0.05. However, finishing with diamond burs showed a statistically higher average roughness for all composites (p<0.05. Statistical differences were detected among materials (p<0.05 in the use of diamond burs.

  10. Characterization of the polishing induced contamination of fused silica optics

    Science.gov (United States)

    Pfiffer, Mathilde; Longuet, Jean-Louis; Labrugère, Christine; Fargin, Evelyne; Bousquet, Bruno; Dussauze, Marc; Lambert, Sébastien; Cormont, Philippe; Néauport, Jérôme

    2016-12-01

    Secondary Ion Mass Spectroscopy (SIMS), Electron Probe Micro Analysis (EPMA) and X-Ray Photoelectron Spectroscopy (XPS) were used to analyze the polishing induced contamination layer at the fused silica optics surface. Samples were prepared using an MRF polishing machine and cerium-based slurry. The cerium and iron penetration and concentration were measured in the surface out of defects. Cerium is embedded at the surface in a 60 nm layer and concentrated at 1200 ppmw in this layer while iron concentration falls down at 30 nm. Spatial distribution and homogeneity of the pollution were also studied in scratches and bevel using SIMS and EPMA techniques. An overconcentration was observed in the chamfer and we saw evidence that surface defects such as scratches are specific places that hold the pollutants. A wet etching was able to completely remove the contamination in the scratch.

  11. Perceptions of and Attitudes towards Regional Varieties of Polish: Views from Two Polish Provinces

    Science.gov (United States)

    Milobog, Magdalena; Garrett, Peter

    2011-01-01

    This paper reports a study of perceptions and attitudes relating to regional varieties of Polish. The methodology followed folk linguistic approaches to attitudes research. Respondents in two Polish provinces were asked to draw on a map of Poland where they thought the main regional varieties of Polish were spoken, and then to name and…

  12. Metallographic preparation of Zn-21Al-2Cu alloy for analysis by electron backscatter diffraction (EBSD).

    Science.gov (United States)

    Rodríguez-Hernández, M G; Martínez-Flores, E E; Torres-Villaseñor, G; Escalera, M Dolores

    2014-08-01

    Samples of Zn-21Al-2Cu alloy (Zinalco) that will be heavily deformed were prepared using five different manual mechanical metallographic methods. Samples were analyzed before tensile testing using the orientation imaging microscopy-electron backscatter diffraction (OIM-EBSD) technique. The effect of type and particle size during the final polishing stages for this material were studied in order to identify a method that produces a flat, damage free surface with a roughness of about 50 nm and clean from oxide layers, thereby producing diffraction patterns with high image quality (IQ) and adequate confidence indexes (CI). Our results show that final polishing with alumina and silica, as was previously suggested by other research groups for alloys that are difficult to prepare or alloys with low melting point, are not suitable for manual metallographic preparation of this alloy. Indexes of IQ and CI can be used to evaluate methods of metallographic preparation of samples studied using the OIM-EBSD technique.

  13. Lexical Server of Polish Language

    Directory of Open Access Journals (Sweden)

    Marek Gajecki

    2001-01-01

    Full Text Available This paper presents Lexical Server of Polish Language, the tool that aids natural language processing (NLP. Database of the server consists of dictionary units enriched by lexical information. The lexical server should be able to perform identification of word forms and generations of all inflected forms of the word. The server is dedicated to the people who are looking for NLP algorithms or implement them. The algorithms can be implemented in different kinds of programming languages and different operating systems. There are some examples of problems when lexical server can be useful: automatic text correction, tcxt indexing, keywords extraction, text profile building.

  14. Polish Foundation for Energy Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The Polish Foundation for Energy Efficiency (FEWE) was established in Poland at the end of 1990. FEWE, as an independent and non-profit organization, has the following objectives: to strive towards an energy efficient national economy, and to show the way and methods by use of which energy efficiency can be increased. The activity of the Foundation covers the entire territory of Poland through three regional centers: in Warsaw, Katowice and Cracow. FEWE employs well-known and experienced specialists within thermal and power engineering, civil engineering, economy and applied sciences. The organizer of the Foundation has been Battelle Memorial Institute - Pacific Northwest Laboratories from the USA.

  15. SELECTED FEATURES OF POLISH FARMERS

    Directory of Open Access Journals (Sweden)

    Grzegorz Spychalski

    2013-12-01

    Full Text Available The paper presents results of the research carried out among farm owners in Wielkopolskie voivodeship referring to selected features of social capital. The author identifies and estimates impact of some socio-professional factors on social capital quality and derives statistical conclusion. As a result there is a list of economic policy measures facilitating rural areas development in this aspect. The level of education, civic activity and tendency for collective activity are main conditions of social capital quality in Polish rural areas.

  16. Structure of nanocomposites of Al–Fe alloys prepared by mechanical alloying and rapid solidification processing

    Indian Academy of Sciences (India)

    S S Nayak; B S Murty; S K Pabi

    2008-06-01

    Structures of Al-based nanocomposites of Al–Fe alloys prepared by mechanical alloying (MA) and subsequent annealing are compared with those obtained by rapid solidification processing (RSP). MA produced only supersaturated solid solution of Fe in Al up to 10 at.% Fe, while for higher Fe content up to 20 at.% the nonequilibrium intermetallic Al5Fe2 appeared. Subsequent annealing at 673 K resulted in more Al5Fe2 formation with very little coarsening. The equilibrium intermetallics, Al3Fe (Al13Fe4), was not observed even at this temperature. In contrast, ribbons of similar composition produced by RSP formed fine cellular or dendritic structure with nanosized dispersoids of possibly a nano-quasicrystalline phase and amorphous phase along with -Al depending on the Fe content in the alloys. This difference in the product structure can be attributed to the difference in alloying mechanisms in MA and RSP.

  17. Preparation and Mechanical Properties of Al2O3/Al Laminated Ceramic Matrix Composites

    Institute of Scientific and Technical Information of China (English)

    HUANG Kangming; LI Weixin; XIE Binhuan; RAO Pinggen; PENG Cheng; CHEN Dabo; WU Jianqing

    2011-01-01

    Three series of Al2O3/Al laminated ceramic matrix composites,named SPA,SPV and HP,were fabricated by different methods.SPA and SPV were prepared using Al2O3 slices and Al slurry via screen printing and subsequent heat treatment in air or vacuum.HP samples were made by hot pressing the layered stack of Al foils and Al2O3 slices.SEM and XRD were applied to analyze the microstructure and the interlayer crystal phase.The bending strength,fracture toughness and fracture work of the samples made by the three methods were measured and compared.The results show that the composites have much better toughness and higher fracture work than the Al2O3 slice.Among the samples made by the three methods,the samples made by hot pressing have the optimum mechanical performance.The displacement-load curves and fracture mechanism were analyzed.

  18. Design and preparation of Zn-based materials possessing both high damping and good mechanical properties

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new idea of design and manufacture of metal-based materials possessing both high damping and good mechanical properties was proposed. The key of the idea is the combination of fining restriction-damping structures, using all mechanisms and taking advantages of different materials. Based upon this idea a foam ZA27 was prepared by the technology of prefabricated salt-mass centrifugal seeping foundry, its tensile strength and compressive strength are 83~119 MPa and 100~189 MPa, respectively. The damping properties of the foam ZA27 increase remarkably after the carpenter pastern or rosin (the damping-increased materials) was immerged into it, which approaches to the level of viscous-elastic polymer materials (Q-1≥20×10-3).

  19. Preparation of Basalt Incorporated Polyethylene Composite with Enhanced Mechanical Properties for Various Applications

    Directory of Open Access Journals (Sweden)

    Bredikhin Pavel

    2017-01-01

    Full Text Available The present article showed the possibility of increasing the complex of mechanical properties of polyolefins with dispersed mineral fillers obtained by fine grinding of basalt rocks via ball mill processing. The composites based on dispersed basalt, which were derived from Samara rock mass (Russia with rare earth elements containing, were obtained by extrusion combining the binder and filler, followed by preparation injection-molded test samples. The study of mechanical properties of materials developed showed the possibility of a significant increase in strength characteristics of different types of polyethylene: the breaking stress at static bending for HDPE can be increasing more than 60% and the impact strength by more than 4 times. In addition the incorporation of the dispersed basalt also enhanced the thermal properties of the composites (the oxygen index of HDPE increases from 19 to 25%.

  20. Preparation and Mechanical Properties of Glass Coats with High Temperature Radar Absorber

    Institute of Scientific and Technical Information of China (English)

    ZHU Dong-mei; LUO Fa; XIONG Liang-ming; ZHOU Wan-cheng

    2006-01-01

    BaO-La2O3-B2O3 (BLB) glass, suitable to be used as a sealing between metals, was chosen to be the binder in preparing glass coats on the Ti-alloy substrate. The SiCN nano-powder was introduced as the filler for the absorbing coat because it is considered to be a good high temperature absorber. The effect of the coating temperature and coating time on the tensile strength of the glass coat was investigated and the proper coating parameters to get good mechanical properties were determined. In addition, the effects of the SiCN content on the tensile strength of the absorbing coat were also discussed. Results show that it is possible to prepare the glass coat using the BLB glass as a binder. That the coat formed at 730 ℃ for 30 min has the best tensile strength witnesses 730 ℃, 30 min to be the proper parameter to prepare the glass coat. The BLB glass coat without SiCN powder possesses good tensile strength and the introduction of the SiCN absorber into the glass coat will lower the tensile strength. As the SiCN content increases, the tensile strength of the absorbing coat decreases, which could be attributed to the aggregation of SiCN in the coats.

  1. The Influence of Surface Polish and Beverages on the Roughness of Nanohybrid and Microhybri Resin Composites

    Directory of Open Access Journals (Sweden)

    Sadeghi M

    2016-03-01

    Full Text Available Statement of the Problem: Surface roughness is a key factor in the aesthetics of restorative dentistry as it can determine the clinical quality and success of restorative materials. The chemical process of dissolution in the presence of mechanical forces can accelerate the surface roughness of tooth-coloured restorative materials. Objectives: To determine the degree of surface roughness of a microhybrid and a nanohybrid resin composite after polishing and immersion in various solutions. Materials and Methods: Two resin composites were used : a microhybrid (Gradia direct, GC, and a nanohybrid (Ice, SDI. A total of 54 disc-shaped specimens were prepared for each composite and immersed in distilled water incubated at 37 °C for 24 hours. After 24 h, the baseline measurement for surface roughness (Ra was performed and the specimens were divided into 3 groups of 18 and tested with unpolished or after polishing with Sof-Lex disc and Enhance point systems. Specimens in each group were subdivided into 3 subgroups (n = 6 and immersed in 3 solutions (distilled water, coffee, and cola for 7 days incubated at 37 °C. After 7 days, the specimens were rinsed with tap water for 10 seconds, dried with paper towel and Ra was measured again. Two randomly selected specimens of each group were sputter coated with gold and examined using a Field-Emission Scanning Electron Microscope (SEM. Results: Gradia direct showed a greater Ra than ice in all solutions for all polishing systems (p < 0.001. Specimens polished with Enhance point revealed a significantly greater roughness than Sof-Lex discs and both showed greater Ra than unpolished specimens. Specimens immersed in coffee exhibited significantly greater surface roughness than that of distilled water (p < 0.05 and cola (p < 0.001. Conclusions: Nano-hybrid composite showed a significantly smoother surface than microhybrid. Coffee exhibited the highest Ra compared to distilled water and cola. Enhance point revealed

  2. Preparation and mechanical properties of photo-crosslinked poly(trimethylene carbonate) and nano-hydroxyapatite composites

    NARCIS (Netherlands)

    Geven, Mike A.; Barbieri, Davide; Yuan, Huipin; de Bruijn, Joost D.; Grijpma, Dirk W.

    2015-01-01

    Composite materials of photo-crosslinked poly(trimethylene carbonate) and nanoscale hydroxyapatite were prepared and their mechanical characteristics for application as orbital floor implants were assessed. The composites were prepared by solvent casting poly(trimethylene carbonate) macromers with v

  3. Experimental and Numerical Study of the Influence of Substrate Surface Preparation on Adhesion Mechanisms of Aluminum Cold Spray Coatings on 300M Steel Substrates

    Science.gov (United States)

    Nastic, A.; Vijay, M.; Tieu, A.; Rahmati, S.; Jodoin, B.

    2017-07-01

    The effect of substrate surface topography on the creation of metallurgical bonds and mechanical anchoring points has been studied for the cold spray deposition of pure aluminum on 300M steel substrate material. The coatings adhesion strength showed a significant decrease from 31.0 ± 5.7 MPa on polished substrates to 6.9 ± 2.0 MPa for substrates with roughness of 2.2 ± 0.5 μm. Strengths in the vicinity of 45 MPa were reached for coatings deposited onto forced pulsed waterjet treated surfaces with roughnesses larger than 33.8 μm. Finite element analysis has confirmed the sole presence of mechanical anchoring in coating adhesion strength for all surface treatment except polished surfaces. Grit embedment has been shown to be non-detrimental to coating adhesion for the current deposited material combination. The particle deformation process during impacts has been studied through finite element analysis using the Preston-Tonks-Wallace (PTW) constitutive model. The obtained equivalent plastic strain (PEEQ), temperature, contact pressure and velocity vector were correlated to the particle ability to form metallurgical bonds. Favorable conditions for metallurgical bonding were found to be highest for particles deposited on polished substrates, as confirmed by fracture surface analysis.

  4. Preparation of MWNTs/Al2O3 composites and their mechanical and electrical properties

    Institute of Scientific and Technical Information of China (English)

    FAN; Jinpeng; ZHAO; Daqing; XU; Zening; WU; Minsheng

    2005-01-01

    The mechanical and electrical properties of MWNTs/Al2O3 composite prepared fabricated by hot pressing are investigated. The relation between properties and microstructure of composites is also discussed. With 4wt% MWNTs as reinforcement, the fracture toughness of composite obtained reaches 5.55 Mpa·m1/2, which is 80% higher than that of pure Al2O3 obtained in the same conditions. The main toughening mechanism is CNTs' pinning alumina grain boundaries, and the pullout of CNTs takes effect also. Through adding 2wt% MWNTs and altering the mix method, the fracture toughness of the composite obtained is 3.97 Mpa·m1/2. Furthermore, the electrical resistivity is as low as 8.4×10-3Ω·m, decreasing by 14 orders of magnitude compared with pure alumina ceramics. The function of CNTs in composite is related to the distribution state of CNTs in composite, and the distribution state of CNTs in matrix is dependent on preparation procedures.

  5. Preparation of magnetic rubber with high mechanical properties by latex compounding method

    Science.gov (United States)

    Hou, Chunlin; Gao, Li; Yu, Hailing; Sun, Youyi; Yao, Junru; Zhao, Guizhe; Liu, Yaqing

    2016-06-01

    the magnetic rubber based on Fe3O4 nanoparticles and nature rubber were prepared by latex compounding method, in which stable Fe3O4 aqueous solutions were mixed with natural rubber latex and additives. This process was fast, versatile, reliable, safe, environmentally friendly and inexpensive. What's more, it was found that the magnetic and mechanical properties of magnetic rubber increased together with increase in doping content of Fe3O4 nanoparticles. Especially, it was demonstrated that the tensile strength (25.0 Mpa) of magnetic rubber was improved to be 478.0% comparing to neat natural rubber (5.2 Mpa), which was 5 times higher than maximal value reported in previous work. At the same time, the magnetic rubber revealed better thermal stability and solvent resistance comparing to the neat natural rubber, too. The work dose not only provides a new way to environmentally friendly preparation of magnetic rubber at low temperature, but also improve the mechanical and magnetic properties of magnetic rubber applied in industry.

  6. Nanocrystalline Al7075 + 1 wt % Zr Alloy Prepared Using Mechanical Milling and Spark Plasma Sintering.

    Science.gov (United States)

    Molnárová, Orsolya; Málek, Přemysl; Veselý, Jozef; Šlapáková, Michaela; Minárik, Peter; Lukáč, František; Chráska, Tomáš; Novák, Pavel; Průša, Filip

    2017-09-20

    The microstructure, phase composition, and microhardness of both gas-atomized and mechanically milled powders of the Al7075 + 1 wt % Zr alloy were investigated. The gas-atomized powder exhibited a cellular microstructure (grain size of a few µm) with layers of intermetallic phases along the cell boundaries. Mechanical milling (400 revolutions per minute (RPM)/8 h) resulted in a grain size reduction to the nanocrystalline range (20 to 100 nm) along with the dissolution of the intermetallic phases. Milling led to an increase in the powder's microhardness from 97 to 343 HV. Compacts prepared by spark plasma sintering (SPS) exhibited negligible porosity. The grain size of the originally gas-atomized material was retained, but the continuous layers of intermetallic phases were replaced by individual particles. Recrystallization led to a grain size increase to 365 nm in the SPS compact prepared from the originally milled powder. Small precipitates of the Al₃Zr phase were observed in the SPS compacts, and they are believed to be responsible for the retainment of the sub-microcrystalline microstructure during SPS. A more intensive precipitation in this SPS compact can be attributed to a faster diffusion due to a high density of dislocations and grain boundaries in the milled powder.

  7. Nanocrystalline Al7075 + 1 wt % Zr Alloy Prepared Using Mechanical Milling and Spark Plasma Sintering

    Directory of Open Access Journals (Sweden)

    Orsolya Molnárová

    2017-09-01

    Full Text Available The microstructure, phase composition, and microhardness of both gas-atomized and mechanically milled powders of the Al7075 + 1 wt % Zr alloy were investigated. The gas-atomized powder exhibited a cellular microstructure (grain size of a few µm with layers of intermetallic phases along the cell boundaries. Mechanical milling (400 revolutions per minute (RPM/8 h resulted in a grain size reduction to the nanocrystalline range (20 to 100 nm along with the dissolution of the intermetallic phases. Milling led to an increase in the powder’s microhardness from 97 to 343 HV. Compacts prepared by spark plasma sintering (SPS exhibited negligible porosity. The grain size of the originally gas-atomized material was retained, but the continuous layers of intermetallic phases were replaced by individual particles. Recrystallization led to a grain size increase to 365 nm in the SPS compact prepared from the originally milled powder. Small precipitates of the Al3Zr phase were observed in the SPS compacts, and they are believed to be responsible for the retainment of the sub-microcrystalline microstructure during SPS. A more intensive precipitation in this SPS compact can be attributed to a faster diffusion due to a high density of dislocations and grain boundaries in the milled powder.

  8. Study of Influencing Factors and the Mechanism of Preparing Triazinedithiol Polymeric Nanofilms on Aluminum Surfaces

    Directory of Open Access Journals (Sweden)

    Yanni Li

    2010-11-01

    Full Text Available Triazinedithiol polymeric nanofilm was prepared on a pure aluminum surface by electrochemical polymerization of AF17N. The mechanism of the process was proposed and electrochemical polymerization parameters were investigated. The triazinedithiol polymeric nanofilm had notable lubricity, high dielectric property and superhydrophobic property due to the allyl and fluoro alkyl groups in the AF17N monomer. The chemical structure of poly (6-(N-allyl-1,1,2,2-tetrahydroperfluorodecylamino-1,3,5-triazine-2,4-dithiol monosodium nanofilm (PAF17 was investigated by analysis of FT-IR spectra and X-ray photoelectron spectroscopy (XPS. The optimal conditions for the preparation process were based on the data of film weight and thickness. The optimal parameters of monomer concentration, electropolymerization time and temperature were 5 mM, 6 min and 15 °C, respectively. The electropolymerization mechanism was a radical polymerization reaction. It is expected that this technique will be applied in industrial fields for aluminum and aluminum alloy to achieve functional surfaces.

  9. Melting of iron nanoparticles embedded in silica prepared by mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Peng; Ma, Ji [Institute of Materials Science and Engineering, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Cao, Hui, E-mail: caoh@lzu.edu.cn [Institute of Materials Science and Engineering, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Liu, Yi [Department of Biology Science, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201203 (China); Wang, Lianwen, E-mail: lwwang@lzu.edu.cn [Institute of Materials Science and Engineering, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Li, Jiangong [Institute of Materials Science and Engineering, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China)

    2013-08-20

    Highlights: • Melting of metallic nanoparticles was studied for some eight elements. • This slim range of materials is successfully expanded to iron. • A mechanical-milled iron–silica composite is employed. • For iron particles of 15 nm in diameter, the melting point depression is 30 K. • The measured data is in agreement with our theoretical calculations. -- Abstract: For decades, experimental studies on the size-dependent melting of metals are regretfully limited to some eight archetypal examples. In this work, to expand this slim range of materials, the melting behavior of Fe nanoparticles embedded in SiO{sub 2} prepared by using mechanical milling are investigated. Effects of factors in sample preparation on the size, isolation and thermal stability of Fe nanoparticles are systematically studied. On this basis, the size-dependent melting of Fe is successfully traced: for Fe nanoparticles with a diameter of about 15 nm, the melting point depression is 30 °C in comparison with bulk Fe, in accordance with our recent theoretical prediction.

  10. Effect of heat treatment on Fe-B-Si-Nb alloy powder prepared by mechanical alloying

    Directory of Open Access Journals (Sweden)

    Rodrigo Estevam Coelho

    2005-06-01

    Full Text Available The effect of heat treatment on crystallization behavior of Fe73.5B15Si10Nb1.5 alloy powder prepared by mechanical alloying was studied. The powder samples were prepared by mechanical alloying (MA and for different milling times (1, 5, 25, 70 and 100 hours. Crystalline powders of iron, boron, silicon and niobium were sealed with tungsten carbide balls in a cylindrical vial under nitrogen atmosphere. The ball-to-powder weight ratio was 20 to 1. A Fritsch Pulverizette 5 planetary ball mill was used for MA the powders at room temperature and at 250 rpm. To study the microstructural evolution, a small amount of powder was collected after different milling times and examined by X-ray diffraction, using CuKalpha radiation (lambda = 0.15418 nm. The crystallization behavior was studied by differential thermal analysis, from 25 up to 1000 °C at a heating rate of 25 °C min-1.

  11. Structural and ferroelectrical properties of bismuth titanate ceramic powders prepared by mechanically assisted synthesis

    Directory of Open Access Journals (Sweden)

    Lazarević Z.Ž.

    2007-01-01

    Full Text Available Nanosized bismuth titanate, Bi4Ti3O12, was prepared via a high-energy ball milling process through mechanically assisted synthesis directly from the oxide mixture of Bi2O3 and TiO2. The Bi4Ti3O12 phase started to form after 1 h of milling. With increasing the milling time from 3 to 12 h, the particle size of formed Bi4Ti3O12 did not reduce significantly. The grain size was less than 16 nm and showed a strong tendency to agglomeration. The nucleation and phase formation of Bi4Ti3O12, crystal structure, microstructure, powder grain size and specific surface area were followed by XRD, Rietveld refinement analysis, SEM and the BET specific surface area measurements. Raman spectroscopy was used to explain the structural properties of Bi4Ti3O12 powder, prepared by mechanically assisted synthesis. Reduction in grain size with the increase of milling time was also noted (change in the position and relative intensity, which indicated changes in the structure, caused by nanodimension grains. The sample milled for 12 h and subsequently sintered at 1000°C for 24 h exhibited a hysteresis loop, confirming that the synthesized material possesses ferroelectric properties. .

  12. Preparation and mechanism of the sintered bricks produced from Yellow River silt and red mud.

    Science.gov (United States)

    He, Hongtao; Yue, Qinyan; Su, Yuan; Gao, Baoyu; Gao, Yue; Wang, Jingzhou; Yu, Hui

    2012-02-15

    The preparation, characteristics and mechanisms of sintered bricks manufactured by Yellow River silt and red mud were studied. The sintering shrinkage, weight loss on ignition, water absorption and compressive strength were tested to determine the optimum preparation condition. Sintering mechanisms were discussed through linear regression analysis. Crystalline components of raw materials and bricks were analyzed by X-ray diffraction. Leaching toxicity of raw materials and bricks were measured according to sulphuric acid and nitric acid method. Radiation safety of the sintered bricks was characterized by calculating internal exposure index and external exposure index. The results showed that at the chosen best parameters (red mud content of 40%, sintering temperature of 1050°C and sintering time of 2h), the best characteristics of sintered bricks could be obtained. The weight loss on ignition of sintered bricks was principally caused by the removal of absorbed water and crystal water. The sintering shrinkage of sintered bricks mainly depended on sodium compounds and iron compounds of red mud. The sintering process made some components of raw materials transform into other crystals having better thermostability. Besides, the leaching toxicity and radioactivity index of sintered bricks produced under the optimum condition were all below standards.

  13. Microstructure and mechanical properties of magnesium alloy prepared by lost foam casting

    Institute of Scientific and Technical Information of China (English)

    TIAN Xue-feng; FAN Zi-tian; HUANG Nai-yu; WU He-bao; DONG Xuan-pu

    2005-01-01

    The microstructure and mechanical properties of AZ91 alloy prepared by lost foam casting(LFC) and various heat treatments have been investigated.The microstructure of the AZ91 alloy via LFC consists of dominant α-Mg and β-Mg17Al12 as well as a new phase Al32 Mn25 with size of about 5-50 μm,which has not been detected in AZ91 alloy prepared by other casting processes.The tests demonstrate that the as-cast mechanical properties are higher than those of sand gravity casting because of chilling and cushioning effect of foam pattern during the mould filling.The solution kinetics and the aging processes at different temperatures were also investigated by hardness and electrical resistivity measurements.The kinetics of aging are faster at the high temperature due to enhanced diffusion of atoms in the matrix,so the hardness peak at 380 ℃ occurs after 10 h;while at the lower aging temperature(150 ℃),the peak is not reached in the time(24 h) considered.

  14. Compressive elastic moduli and polishing performance of non-rigid core/shell structured PS/SiO{sub 2} composite abrasives evaluated by AFM

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ailian [College of Mechanical and Energy Engineering, Changzhou University, Changzhou, Jiangsu 213016 (China); Mu, Weibin [School of Materials Science and Engineering, Changzhou University, Changzhou, Jiangsu 213164 (China); Chen, Yang, E-mail: cy.jpu@126.com [School of Materials Science and Engineering, Changzhou University, Changzhou, Jiangsu 213164 (China)

    2014-01-30

    The core/shell structured polystyrene (PS)/SiO{sub 2} composite microspheres with different silica shell morphology were synthesized by a modified Stöber method. As confirmed by transmission electron microscopy (TEM), the rough discontinuous shell consisted of separate SiO{sub 2} nanoparticles for composite-A, while the smooth continuous one was composed of amorphous silica network for composite-B. Atomic force microscopy (AFM) was employed to probe the compressive Young's moduli (E) and chemical mechanical polishing (CMP) performances of the as-prepared PS/SiO{sub 2} composite microspheres. On the basis of the Hertzian contact mechanics, the calculated E values of the PS microspheres, composite-A and composite-B were 2.9 ± 0.4, 5.1 ± 1.2 and 6.0 ± 1.2 GPa, respectively. Compared to traditional abrasives, thermally grown silicon oxide wafers after polished by the core/shell PS/SiO{sub 2} composite abrasives obtained a lower root mean square roughness and a higher material removal rate value. In addition, there is an obvious effect of shell morphology of the composites on oxide CMP performance and structural stability during polishing process. This approach would provide a basis for understanding the actual role of organic/inorganic core/shell composite abrasives in the material removal process of CMP.

  15. Overestimating hybrid layer quality in polished adhesive/dentin interfaces.

    Science.gov (United States)

    Wang, Yong; Spencer, Paulette

    2004-03-15

    The most popular techniques for determining the quality of the hybrid layer (HL) have relied on morphologic characterization of the polished adhesive/dentin (a/d) interfaces before and after acid-bleach chemical treatment. Using these techniques, the existence of smooth, acid-resistant layers has been consistently reported for most adhesive systems. The purpose of this study was to determine whether popular specimen preparation techniques that include polishing and acid-bleach treatment modify the a/d interface, mask the complexity of the HL, and lead to inaccurate assessment of the quality of the HL. To understand the impact of specimen preparation techniques on the morphology of the resin-dentin interface, polished and unpolished specimens from the same tooth were closely compared after different acid-bleach chemical treatment procedures. Two one-bottle adhesives, that is, 3M Single Bond and Pulpdent UNO, exhibiting distinct differences in hydrophilic/hydrophobic composition, were used in this investigation. Using specimens from the same tooth, the effect of chemical treatments on the morphology of the resin-dentin interdiffusion zone and the differences in the morphology of polished and unpolished specimens after these same treatments were studied with scanning electron microscopy. It was shown that conventional specimen preparation techniques that include polishing and acid-bleach treatment can adversely affect and even obscure the structural detail of the a/d interface in specimens that possess a porous HL. The results indicated that the Pulpdent UNO/dentin interface had better quality than the 3M Single Bond/dentin interface. The difference in the quality of HL can be attributed to factors such as compositional differences that impact the adhesive interaction with water, that is present within the substrate during wet bonding. The inability of the conventional acid-bleach procedure to reveal the differences in the scanning electron microscopy interfacial

  16. The fate of ukrainians in Polish Army

    Directory of Open Access Journals (Sweden)

    V. V. Dashko

    2015-06-01

    Particular attention is devoted to the analysis of the list of polish officers and policemen, who were executed by NKVD and buried in Katyn, Midne and Kharkiv, and also the list of Polish citizens, from the so­called Ukrainian Katyn list. A huge layer of various matters relating to Ukrainians in this tragedy still waits to be studied by historians.

  17. The Bulgarian-Polish-Russian parallel corpus

    Directory of Open Access Journals (Sweden)

    Maksim Duškin

    2015-11-01

    Full Text Available The Bulgarian-Polish-Russian parallel corpus The Semantics Laboratory Team of Institute of Slavic Studies of Polish Academy of Sciences is planning to begin work on the creation of a Bulgarian-Polish-Russian parallel corpus. The three selected languages are representatives of the main groups of Slavic languages: Bulgarian represents the southern group of Slavic languages, Polish – the western group of Slavic languages, Russian – the eastern group of Slavic languages. Our project will be the first parallel corpus of these three languages. The planned corpus will be based on material, dating from one period (the 20th century and will have a synchronous nature. The project will not constitute the sum of the separate corpora of selected languages. One of the problems with creating multilingual parallel corpora are different proportions of translated texts between the selected languages, for example, Polish literature is often translated into Bulgarian, but not vice versa. Bulgarian, Russian and Polish differ typologically – Bulgarian is an analytic language, Polish and Russian are synthetic. The parallel corpus should have compatible annotation, while taking into account the characteristic features of the selected languages. We hope that the Bulgarian-Polish-Russian parallel corpus will serve as a source of linguistic material of contrastive language studies and may prove to be a big help for linguists, translators, terminologists and students of linguistics. The results of our work will be available on the Internet.

  18. Effect of the geometry of workpiece on polishing velocity in free annular polishing

    Institute of Scientific and Technical Information of China (English)

    Quantang Fan; Jianqiang Zhu; Bao'an Zhang

    2007-01-01

    Base on Coulomb friction model, the workpieces with different geometry rotating in free annular polishing are simulated. From simulation, the following conclusions are drawn. The angular velocity of workpiece is higher than that of polishing pad if the ring rotates uncontrolled in free annular polishing. The circular workpiece can synchronize with polishing pad through controlling the rotation of ring, which depends on the radii of ring and workpiece, the friction coefficients of polishing pad-workpiece and ring-workpiece,and the angular velocity of polishing pad. The workpiece with sharp corner cannot contact with the ring contiguously, which causes the contact state changing and the angular velocity of workpiece fluctuating ceaselessly, and this type of workpiece should be controlled with clamp to rotate synchronistically with the polishing pad.

  19. Polish Industry and Art at CERN

    CERN Document Server

    2000-01-01

    On 17 October 2000 the second Polish industrial and technological exhibition opened at CERN. The first one was held five years ago and nine of the companies that were present then have come back again this year. Six of those companies were awarded contracts with CERN in 1995. Three Polish officials were present at the Opening Ceremony today: Mrs Malgorzata Kozlowska, Under-secretary of State in the State Committee for Scientific Research, Mr Henryk Ogryczak, Under-secretary of State in Ministry of Economy and Prof. Jerzy Niewodniczanski, President of National Atomic Energy Agency. Professor Luciano Maiani welcomed the Polish delegation to CERN and stressed the important contribution of Polish scientists and industrialists to the work of the laboratory. Director General Luciano Maiani (back left) and head of SPL division Karl-Heinz Kissler (back right) visit the Poland at CERN exhibition… The exhibition offers Polish companies the opportunity to establish professional contacts with CERN. Nineteen companies...

  20. Chemical Mechanical Polishing of Os in H3PO4-Based Slurries%锇在磷酸体系抛光液中化学机械抛光研究

    Institute of Scientific and Technical Information of China (English)

    储向峰; 汤丽娟; 董永平; 乔红斌; 朱小华

    2013-01-01

    (锇有可能作为大规模集成电路铜互连扩散阻挡层新材料.)利用自制的抛光液对金属锇片进行抛光,研究在双氧水-磷酸体系抛光液中H2O2浓度和抛光液pH值对抛光速率的影响.结果表明,当抛光液中主要成分仅为氧化剂H2O2时,并不能在金属锇表面达到好的腐蚀效果.在磷酸体系抛光液中,H2O2能够通过促进阴极反应的进行从而增强抛光液对金属锇的化学作用;低浓度H2O2通过增强抛光液对金属锇的化学腐蚀能力,从而增加了抛光速率值:较高浓度H2O2的加入对抛光速率值影响较小.H3PO4能够在抛光液中起到抑制剂、pH调节剂和络合剂的作用.当抛光液pH值为4.0时,金属锇表面生成的钝化膜最致密.当pH值为4.0或5.0时,金属锇表面生成的钝化膜OCP值大于金属锇的OCP值,且此条件下的抛光速率值较高.%Osmium (Os) may be used in copper interconnects of ultra-large scale integration as a new barrier material.In this work,chemical mechanical polishing experiments were performed on Os disk using home-made H3PO4-based slurries and the effect of the H2O2 concentration and pH value on the material removal rate (MRR) was investigated.Good corrosion cannot be obtained on Os surface when only H2O2 is the main components in slurry.In H3PO4-based slurries,H2O2 can accelerate the cathode reaction and enhance the chemical action of the slurry on the surface of Os.Low concentration H2O2 promotes the chemical corrosion ability to corrode Os surface and increases the material removal rate; the increasing of H2O2 concentration has less influences on the MRR when the concentration of H2O2 is higher.Phosphoric acid plays a role of inhibitor,pH adjusting agent and complexing agent in the slurry.When pH value is 4.0,the passive film on the surface of Os is most compact.The OCP values of the passive films formed on the surface of Os are higher than those of Os and the MRR attains higher values when the pH value

  1. PREPARATION AND MECHANICAL PROPERTIES OF T-ZnOw/PS COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Yong Wang; Jing Shi; Zheng-bao He; Hong-wei Bai

    2009-01-01

    The main subject of this work is about the preparation of T-ZnOw/PS composites through different methods and the evaluation of mechanical properties of the composites.Different surface modification methods of T-ZnOw whiskers,the so called wet-type modification and dry-type modification,and different molding processing methods of T-ZnOw/PS composites,namely compression molding and injection molding,have been employed.Two different coupling agents,titanate coupling agent (NDZ105) and silane coupling agent (KH560),have been used to treat T-ZnOw.Both the interface structure between T-ZnOw whiskers and PS and the distribution of integrated T-ZnOw whiskers in composites have been studied by SEM.The mechanical properties of T-ZnOw/PS composites obtained through the above different methods have been studied comparatively.Although the tensile strength of the composites decreases slightly,the impact strength and tensile modulus increase with increasing the content of T-ZnOw in the composites.Both coupling agents and molding methods have great influence on the mechanical properties of the composites.The study of the impact-fractured surface shows that craze formation in PS matrix during the impact process is the main reason for the improvement of the composite toughness.

  2. PREPARING A COMPREHENSIVE ANALYSIS OF THE MECHANICAL CLASSIFICATION OF STRUCTURAL GLASS

    Directory of Open Access Journals (Sweden)

    Gergely Molnár

    2012-03-01

    Full Text Available Present study deals with the mesostructure analysis of the structural glass. The subject is about to prepare a comprehensive mechanical analysis, aimed on the understanding of the multiscale mechanical behaviour of soda-lime-silica glass used as an architectural element.After a brief description of the micro and mesostructure of glass we will explain our goals in this analysis.We have divided the glass plate – from a mesoscopic aspect – into three major regions. The first region is the external surface, which is the largest area of a plate. The effect of the surface imperfections is negligible due to a grinded edge finishing, so we considered the second region as the edge. The third region contains the inhomogeneities in the glass material itself. To describe the mesostructure we have done atomic force microscopy (AFM and micro computed tomography (µCT scans. We used the AFM to image the surface and the edge and µCT to collect geometrical information from the inhomogeneities. The aim of the overall analysis is to develop a new certification procedure to qualify the structural glass in a mechanical a way.

  3. PREPARING A COMPREHENSIVE ANALYSIS OF THE MECHANICAL CLASSIFICATION OF STRUCTURAL GLASS

    Directory of Open Access Journals (Sweden)

    Gergely Molnár

    2012-02-01

    Full Text Available Present study deals with the mesostructure analysis of the structural glass. The subject is about to prepare a comprehensive mechanical analysis, aimed on the understanding of the multiscale mechanical behaviour of soda-lime-silica glass used as an architectural element. After a brief description of the micro and mesostructure of glass we will explain our goals in this analysis. We have divided the glass plate – from a mesoscopic aspect – into three major regions. The first region is the external surface, which is the largest area of a plate. The effect of the surface imperfections is negligible due to a grinded edge finishing, so we considered the second region as the edge. The third region contains the inhomogeneities in the glass material itself. To describe the mesostructure we have done atomic force microscopy (AFM and micro computed tomography (µCT scans. We used the AFM to image the surface and the edge and µCT to collect geometrical information from the inhomogeneities. The aim of the overall analysis is to develop a new certification procedure to qualify the structural glass in a mechanical a way.

  4. Effects of different polishing methods on color stability of resin composites after accelerated aging.

    Science.gov (United States)

    Sirin Karaarslan, Emine; Bulbul, Mehmet; Yildiz, Esma; Secilmis, Asli; Sari, Fatih; Usumez, Aslihan

    2013-01-01

    The purpose of this study was to evaluate the effect of polishing procedures on the color stability of different types of composites after aging. Forty disk-shaped specimens (Ø10×2 mm) were prepared for each composite resin type (an ormocer, a packable, a nanohybrid, and a microhybrid) for a total of 160 specimens. Each composite group was divided into four subgroups according to polishing method (n=10): control (no finishing and polishing), polishing disk, polishing wheel, and glaze material. Color parameters (L*, a*, and b*) and surface roughness were measured before and after accelerated aging. Of the polishing methods, glazed specimens showed the lowest color change (∆E*), ∆L*, and ∆b* values (p<0.05). Of the composite resins, the microhybrid composite showed the lowest ∆E* value, whereas the ormocer showed the highest (p<0.05). For all composite types, the surface roughness of their control groups decreased after aging (p<0.05). In conclusion, all composite resins showed color changes after accelerated aging, with the use of glaze material resulting in the lowest color change.

  5. Electrochemical Polishing Applications and EIS of a Vitamin B{sub 4}-Based Ionic Liquid

    Energy Technology Data Exchange (ETDEWEB)

    Wixtrom, Alex I. [Christopher Newport University, Newport News, VA (United States); Buhler, Jessica E. [Christopher Newport University, Newport News, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Abdel-Fattah, Tarek M. [Christopher Newport University, Newport News, VA (United States)

    2013-01-01

    Modern particle accelerators require minimal interior surface roughness for Niobium superconducting radio frequency (SRF) cavities. Polishing of the Nb is currently achieved via electrochemical polishing with concentrated mixtures of sulfuric and hydrofluoric acids. This acid-based approach is effective at reducing the surface roughness to acceptable levels for SRF use, but due to acid-related hazards and extra costs (including safe disposal of used polishing solutions), an acid-free method would be preferable. This study focuses on an alternative electrochemical polishing method for Nb, using a novel ionic liquid solution containing choline chloride, also known as Vitamin B{sub 4} (VB{sub 4}). Potentiostatic electrochemical impedance spectroscopy (EIS) was also performed on the VB4-based system. Nb polished using the VB4-based method was found to have a final surface roughness comparable to that achieved via the acid-based method, as assessed by atomic force microscopy (AFM). These findings indicate that acid-free VB{sub 4}-based electrochemical polishing of Nb represents a promising replacement for acid-based methods of SRF cavity preparation.

  6. Preparation and mechanical properties of silicon oxycarbide fibers from electrospinning/sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaofei [School of Materials Sciences and Engineering, Tianjin University, 300072 Tianjin (China); Gong, Cairong, E-mail: gcr@tju.edu.cn [School of Materials Sciences and Engineering, Tianjin University, 300072 Tianjin (China); Fan, Guoliang [School of Materials Sciences and Engineering, Tianjin University, 300072 Tianjin (China)

    2011-12-15

    Graphical abstract: Ceramic fibers, silicon oxycarbide (SiOC) fibers were demonstrated and showed higher mechanical properties from electrospinning/sol-gel process at 1000 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer SiOC fibers with low cost are promising to substitute the non-oxide fibers. Black-Right-Pointing-Pointer Successful preparation of SiOC fibers by electrospinning/sol-gel process. Black-Right-Pointing-Pointer Confirmation of the designed product using material characterization methods. Black-Right-Pointing-Pointer The SiOC fibers prepared at 1000 Degree-Sign C possess higher strength (967 MPa). -- Abstract: Silicon oxycarbide (SiOC) fibers were produced through the electrospinning of the solution containing vinyltrimethoxysilane and tetraethoxysilane in the course of sol-gel reaction with pyrolysis to ceramic. The effect of the amount of spinning agent Polyvinylpyrrolidone (PVP) on the dope spinnability was investigated. At a mass ratio of PVP/alkoxides = 0.05, the spinning sol exhibited an optimal spinnable time of 50 min and generated a large quantity of fibers. Electrospun fibers were characterized by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis-differential scanning calorimetry (TGA-DSC), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The SEM results revealed that the SiOC fibers had a smooth surface and dense cross-section, free of residue pores and cracks. The XPS results gave high content of SiC (13.99%) in SiOC fibers. The SiOC fibers prepared at 1000 Degree-Sign C had a high tensile strength of 967 MPa and Young's modulus of 58 GPa.

  7. Decomposition of BN and formation of Nd2Fe14BNx phase prepared by mechanical alloying

    Science.gov (United States)

    Liu, W.; Zhang, Z. D.; Sun, X. K.; He, J. F.; Zhao, X. G.

    1999-07-01

    The decomposition of pyrolytic boron nitride (p-BN) during milling is studied as a function of the milling time. It has been found that the p-BN compound can be partially decomposed by milling until an amorphous p-BN phase is formed so that the content of nitrogen in the p-BN system will not continue to be changed by the milling process. Furthermore, the structure and magnetic properties of Nd2Fe14BNx-based alloys prepared by mechanical alloying using either p-BN or milled p-BN as starting material have been investigated. The Nd2Fe14BNx phase with x up to 0.25 coexists with some amounts of NdN, the Nd-rich phase and icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/>-Fe. A pre-milling process of p-BN favours the formation of the Nd2Fe14BNx phase. The magnetic properties of Nd16Fe76B8Nx alloys prepared by using milled p-BN are better than those made of non-milled p-BN. The Curie temperature of the Nd2Fe14BN0.25 phase is 335 °C, which is slightly higher than that of the Nd2Fe14B compound. A coercivity higher than 20 kOe is achieved for Nd2Fe14BNx-based alloys by adding excess Nd, which is close to the value of Nd16Fe76B8 prepared by using pure B.

  8. Mechanical and Thermal Properties of Poly(urethane urea Nanocomposites Prepared with Diamine-Modified Laponite

    Directory of Open Access Journals (Sweden)

    Joe-Lahai Sormana

    2008-01-01

    Full Text Available Nanocomposites based on segmented poly(urethane urea were prepared by reacting a poly(diisocyanate with diamine-modified Laponite-RD nanoparticles that served as a chain extender. The nanocomposites were prepared at a constant NH2 to NCO mole ratio of 0.95, while varying the fraction of diamine-modified Laponite relative to the free diamine chain extender. Compared to neat poly(urethane urea, all nanocomposites showed increased tensile strength and elongation at break. As Laponite loading increased, tensile properties passed through a maximum at a particle concentration of 1 mass%, at which a 300% increase in tensile strength and 40% increase in elongation at break were observed. A maximum in urea and urethane hard-domain melting endotherms was also observed at this Laponite loading. Optimal mechanical and thermal properties coincided with a minimum in the size of the inorganic Laponite phase. Nanocomposites containing diamine-modified Laponite had higher tensile strengths than those with nonreactive monoamine-modified Laponite or diamine-modified Cloisite.

  9. Ionic conductivity of apatite-type rare-earth silicates prepared by mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Gonzalez, L.G.; Rodriguez-Reyna, E.; Moreno, K.J.; Escalante-Garcia, J.I. [Cinvestav-Saltillo, Apartado Postal 663, 25000-Saltillo, Coahuila (Mexico); Fuentes, A.F. [Cinvestav-Saltillo, Apartado Postal 663, 25000-Saltillo, Coahuila (Mexico)], E-mail: fuentesaf@live.com

    2009-05-12

    Apatite-type silicates, RE{sub 10-x}(SiO{sub 4}){sub 6}O{sup '}{sub 2+y} (RE = La, Nd, Gd and Dy), were prepared by mechanical milling (MM) starting from stoichiometric mixtures of the constituent oxides, RE{sub 2}O{sub 3} and SiO{sub 2}. XRD patterns collected after grinding the starting mixtures in a planetary ball mill for 9 h contain only the characteristic reflections of the target materials. The electrical properties were analyzed on sintered pellets by using impedance spectroscopy and the isothermal conductivity data were successfully fitted to a Jonscher-type empirical expression {sigma}'({omega}) {proportional_to} {omega}{sup n} with a decreasing fractional exponent n as the RE{sup 3+} cation size increases. Activation energies for oxygen migration were found to decrease and conductivity to increase as the size of the RE{sup 3+} cation increases with the highest conductivity values obtained for the apatite-type lanthanum silicate. In addition, we also show that the electrical properties of the as-prepared materials are influenced by the silicon source used in their synthesis.

  10. Synthesis, microstructure and mechanical properties of ceria stabilized tetragonal zirconia prepared by spray drying technique

    Indian Academy of Sciences (India)

    S C Sharma; N M Gokhale; Rajiv Dayal; Ramji Lal

    2002-02-01

    Ceria stabilized zirconia powders with ceria concentration varying from 6 to 16 mol% were synthesized using spray drying technique. Powders were characterized for their particle size distribution and specific surface area. The dense sintered ceramics fabricated using these powders were characterized for their microstructure, crystallite size and phase composition. The flexural strength, fracture toughness and microhardness of sintered ceramics were measured. High fracture toughness and flexural strength were obtained for sintered bodies with 12 mol% of CeO2. Flexural strength and fracture toughness were dependent on CeO2 concentration, crystallite size and phase composition of sintered bodies. Correlation of data has indicated that the transformable tetragonal phase is the key factor in controlling the fracture toughness and strength of ceramics. It has been demonstrated that the synthesis method is effective to prepare nanocrystalline tetragonal ceria stabilized zirconia powders with improved mechanical properties. Ce–ZrO2 with 20 wt% alumina was also prepared with flexural strength, 1200 MPa and fracture toughness, 9.2 MPa √m.

  11. Structural, microstructural and vibrational characterization of apatite-type lanthanum silicates prepared by mechanical milling

    Science.gov (United States)

    Rodríguez-Reyna, E.; Fuentes, A. F.; Maczka, M.; Hanuza, J.; Boulahya, K.; Amador, U.

    2006-02-01

    Apatite-type lanthanum silicates have been successfully prepared at room temperature by dry milling hexagonal A-La 2O 3 and either amorphous or low cristobalite SiO 2. Milling a stochiometric mixture of these chemicals in a planetary ball mill with a moderate rotating disc speed (350 rpm), allows the formation of the target phase after only 3 h although longer milling times are needed to eliminate all SiO 2 and La 2O 3 traces. Thus, the mechanically activated chemical reaction proceeds faster when using amorphous silica instead of low cristobalite as silicon source and pure phases are obtained after only 9 and 18 h, respectively. As obtained powder phases are not amorphous and show an XRD pattern as well as IR and Raman bands characteristic of the lanthanum silicate. The domain size of the as-prepared phases varies gradually with the temperature of post-milling thermal treatment with activation energies of about 26(8) and 52(10) kJ mol -1 K -1 for the apatites obtained from amorphous silica and low-cristobalite, respectively. These values suggest crystallite growth to be favored when using amorphous silica as reactant.

  12. Polish Adaptation of Wrist Evaluation Questionnaires.

    Science.gov (United States)

    Czarnecki, Piotr; Wawrzyniak-Bielęda, Anna; Romanowski, Leszek

    2015-01-01

    Questionnaires evaluating hand and wrist function are a very useful tool allowing for objective and systematic recording of symptoms reported by the patients. Most questionnaires generally accepted in clinical practice are available in English and need to be appropriately adapted in translation and undergo subsequent validation before they can be used in another culture and language. The process of translation of the questionnaires was based on the generally accepted guidelines of the International Quality of Life Assessment Project (IQOLA). First, the questionnaires were translated from English into Polish by two independent translators. Then, a joint version of the translation was prepared collectively and translated back into English. Each stage was followed by a written report. The translated questionnaires were then evaluated by a group of patients. We selected 31 patients with wrist problems and asked them to complete the PRWE, Mayo, Michigan and DASH questionnaires twice at intervals of 3-10 days. The results were submitted for statistical analysis. We found a statistically significant (pquestionnaires. A comparison of the PRWE and Mayo questionnaires with the DASH questionnaire also showed a statistically significant correlation (pquestionnaires was successful and that the questionnaires may be used in clinical practice.

  13. Preparation and mechanism of Fe3O4/Au core/shell super-paramagnetic microspheres

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In the presence of Fe3O4 nano-particles, a new type of super-paramagnetic Fe3O4/Au microspheres with core/shell structures was prepared by reduction of Au3+ with hydroxylamine. The formation mechanism of the core/shell microspheres was studied in some detail. It was shown that the formation of the complex microspheres can be divided into two periods, that is, surface reaction-controlled process and diffusion-controlled process. The relative time lasted by either process depends upon the amount of Fe3O4 added and the initial concentration of Au3+. XPS analysis revealed that along with increasing in coating amount, the strength of the characteristic peaks of Au increased, and the Auger peaks of Fe weakened and even disappeared. Size distribution analysis showed that the core/shell microspheres are of an average diameter of 180 nm, a little bit larger than those before coating.

  14. Preparation by a Rheological Phase Reaction Method and Thermal Decomposition Reaction Mechanism of Nickelous Salicylate Tetrahydrate

    Institute of Scientific and Technical Information of China (English)

    Wang Jin-long; Yuan Liang-jie; Yang Yi-yong; Sun Ju-tang; Zhang Ke-li

    2003-01-01

    The single crystal nickel salicylate tetrahydrate was prepared with the rheological phase reaction method from nickelous hydroxide and salicylic acid. The crystal structure was determined. It is monoclinic, space group P21 /n, a =0.67874(3), b=0. 515 91(2), c=2. 313 30(9) nm, β=90.9286(17)°, V=0. 809 94(6) nm3, Z=2, ρcalcd =0. 065 0[I >2a(I)]. The thermal decomposition mechanism in an inert atmosphere was investigated via TG, DTG and DTA. The thermal decomposition products were characterized with IR and micro-powder X-ray diffraction method. A new coordination polymer (NiC6 H4O)n as an intermediate product and nanoscale metal nickel were obtained in the ranges of 364-429 ℃ and 429-680 ℃, respectively.

  15. Preparation, Growth Mechanisms and Characterizations of ZnSe Films via the Solvothermal Method

    Institute of Scientific and Technical Information of China (English)

    LI Huan-yong; JIE Wan-qi; ZHAO Hai-tao

    2006-01-01

    With diethylamine as a solvent, ZnSe films were formed on the Si substrate directly from zinc and selenium through the modified solvothermal method. The effects of holding temperature, deposition time and substrate surface treatment on the quality and morphologies of the ZnSe films were investigated. The growth mechanism of ZnSe films was proved to be a layer-nucleation growth process, which was tied in with the Stranski-Krastanov (SK) model. ZnSe films were identified by the X-ray diffraction pattern (XRD), the scanning electron microscope (SEM), the X-ray photoelectron spectroscope (XPS) and the photoluminescence (PL) techniques. The results indicate that the modified solvothermal method with diethylamine as a solvent is suitable to prepare high quality ZnSe films.

  16. Preparation and Photoelectric Conversion Mechanism of Semiconducting ITO/Cu2O Electrodes

    Institute of Scientific and Technical Information of China (English)

    WANG Hua; HE Wei; WANG Hui-xiu; WANG Shou-xu

    2006-01-01

    Semiconducting cuprous oxide films were electrodeposited onto conducting glasses coated with Indium Tin Oxide (ITO) using potentiostatic method. The electrodes were examined by means of X-Ray Diffraction (XRD) and X-ray Photoelectron Spectrum (XPS). The results indicate that the prepared films are cubic Cu2O crystals, and annealing enhances the size and preferred orientation of the films. The photoelectric conversion mechanism of semiconducting ITO/Cu2O electrodes in 0.1 mol/L potassium sulfate (K2SO4) solution is further discussed by using Linear Sweep Voltammetry (LSV) method. The differences of photoelectric conversion of electrodes are reasonably deduced and proved through surfactant modifying, annealing or not, respectively.

  17. Preparation and mechanism of calcium phosphate coatings on chemical modified carbon fibers by biomineralization

    Institute of Scientific and Technical Information of China (English)

    HUANG Su-ping; ZHOU Ke-chao; LI Zhi-you

    2008-01-01

    In order to prepare HA coatings on the carbon fibers, chemical modification and biomineralization processes were applied. The phase components, morphologies, and possible growth mechanism of calcium phosphate were studied by infrared spectroscopy(IR), X-ray diffractometry(XRD) and scanning electron microscopy(SEM). The results show that calcium phosphate coating on carbon fibers can be obtained by biomineralization. But the phase components and morphologies of calcium phosphate coatings are different due to different modification methods. Plate-like CaHPO4-2H2O (DCPD) crystals grow from one site of the active centre by HNO3 treatment. While on the para-aminobenzoic acid treated fibers, the coating is composed of nano-structural HA crystal homogeneously. This is because the -COOH functional groups of para-aminobenzoic acid graft on fibers, with negative charge and arranged structure, accelerating the HA crystal nucleation and crystallization on the carbon fibers.

  18. Study on the preparation and formation mechanism of barium sulphate nanoparticles modified by different organic acids

    Indian Academy of Sciences (India)

    Yuhua Shen; Chuanhao Li; Xuemei Zhu; Anjian Xie; Lingguang Qiu; Jinmiao Zhu

    2007-07-01

    This paper reports a simple method to prepare barium sulphate nanoparticles by use of tetradecanoic acid, hexadecanoic acid and stearic acid as modifier. The barium sulphate nanoparticles obtained are characterized by using Fourier transform infra-red spectroscopy (FT-IR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic laser light scatter (DLLS) and thermogravimetric analysis (TGA), respectively. The results show that the BaSO4 particles are all spherical and in the nano-scale. Our method has a better dispersion and controllable diameter dependent on the length of the chain of organic acid and the pH value of the system. A possible mechanism is also discussed.

  19. Preparation, Characterization and Mechanical Properties of Cu-Sn Alloy/Graphite Composites

    Science.gov (United States)

    Dong, Ruifeng; Cui, Zhenduo; Zhu, Shengli; Xu, Xu; Yang, Xianjin

    2014-10-01

    Ni-B coating was prepared on the surface of graphite particles using the electroless plating method. The Ni-B coating was composed of spherical grains with average diameter of 80 nm. The phases of Ni-B coating were indexed as nanosized crystal Ni phase and amorphous Ni-B phase. Cu-Sn alloy/graphite composites with 0.5, 1.0, 1.5, and 2.0 wt pct graphite contents were synthesized by the powder metallurgy method. Ni-B coating improved the wettability and bonding strength between the Cu-Sn alloy and graphite. The composite with Ni-B coated graphite exhibited higher density, hardness, and compression strength compared with the composites with bare graphite. The crack propagation mechanism of the composites was also analyzed.

  20. Preparation and Mechanical Properties of Ni-TiN Composite Layers by Ultrasonic Electrode Position

    Directory of Open Access Journals (Sweden)

    Jindong Wang

    2013-07-01

    Full Text Available Ultrasonic electrodeposition was used to prepare nanocermet Ni-TiN composite layers on steel substrates. The action of mechanical disturbance by ultrasonic waves on electrolyte mass transfer, the inhibition of nanoparticle aggregation by ultrasonic cavitation and the effect of electric pulse parameters on the nucleation and growth of grains were investigated. The nanocermet Ni-TiN composite layer consisted of nanocrystalline nickel (30~60 nm. The micro-hardness of the composite layers increases a little when TiN content increases from 0% to 2%. However, micro-hardness increases greatly when V is increased from 2% to 9%. The maximal micro-hardness for Ni-TiN composite layers is 860 HV, 908 HV and 950 HV, respectively.

  1. The chitosan prepared from crab tendon I: the characterization and the mechanical properties.

    Science.gov (United States)

    Yamaguchi, Isamu; Itoh, Soichiro; Suzuki, Masumi; Sakane, Masataka; Osaka, Akiyoshi; Tanaka, Junzo

    2003-05-01

    Crystalline chitosan was prepared from crab tendon consisting mainly of chitin, including various proteins and calcium phosphates. The crab tendon has high mechanical properties due to its aligned molecular structure. Crab tendon components, i.e. proteins and calcium phosphates, were removed by deacetyl treatment using 50wt% NaOH aqueous solution at 100 degrees C, and a subsequent ethanol treatment. As judged from microscopic observations using an optical polarizer, the treated chitosan remained intact regarding its aligned molecular structure, and had a high tensile strength of 67.9+/-11.4MPa. The tensile strength was further enhanced to 235+/-30MPa by a thermal treatment at 120 degrees C, corresponding to the formation of the intermolecular hydrogen bonds.

  2. Mechanical Properties of TC4 Matrix Composites Prepared by Laser Cladding

    Directory of Open Access Journals (Sweden)

    WANG Lin

    2017-06-01

    Full Text Available In order to improve the penetration performance of TC4, the direct laser deposition technology was used to prepare TC4 composite material. TA15+30% TiC powder, TA15+20%Cr3C2 powder and TA15+15%B4C powder were used as deposited materials for TC4 matrix. The micromorphology, change of hardness of the deposited coating and mechanical properties of the three composites were studied. The experimental results demonstrate that the TC4 matrix with the three kinds of materials can form a complete metallurgical bonding, and the strength of TC4-(TA15+TiC, TC4-(TA15+Cr3C2 and TC4-(TA15+B4C are higher than that of TC4 matrix materials, while the plasticity is slightly worse.

  3. Preparation and Characterization of Chitosan/Agar Blended Films: Part 2. Thermal, Mechanical, and Surface Properties

    Directory of Open Access Journals (Sweden)

    Esam A. Elhefian

    2012-01-01

    Full Text Available Chitosan/agar (CS/AG films were prepared by blending different proportions of chitosan and agar (considering chitosan as the major component in solution forms. The thermal stability of the blended films was studied using thermal gravimetric analysis (TGA. It was revealed that chitosan and agar form a compatible blend. Studying the mechanical properties of the films showed a decrease in the tensile strength and elongation at break with increasing agar content. Blending of agar with chitosan at all proportions was found to form hydrogel films with enhanced swelling compared to the pure chitosan one. Static water contact angle measurements confirmed the increasing affinity of the blended films towards water suggesting that blending of agar with chitosan improves the wettability of the obtained films.

  4. Preparation and formation mechanism of Al2O3 nanoparticles by reverse microemulsion

    Institute of Scientific and Technical Information of China (English)

    HUANG Ke-long; YIN Liang-guo; LIU Su-qin; LI Chao-jian

    2007-01-01

    Al2O3 nanoparticles were prepared by polyethylene glycol octylphenyl ether(Triton X-100)/n-butyl alcohol/cyclohexane/ water W/O reverse microemulsion. The proper calcination temperature was determined at 1 150 ℃ by thermal analysis of the precursor products. The structures and morphologies of Al2O3 nanoparticles were characterized by X-ray diffraction, transmission electron microscopy and UV-Vis spectra. The influences of mole ratio of water to surfactant on the morphologies and the sizes of the Al2O3 nanoparticles were studied. With the increase of surfactant content, the particles size becomes larger. The agglomeration of nanoparticles was solved successfully. And the formation mechanisms of Al2O3 nanoparticles in the reverse microemulsion were also discussed.

  5. Preparation and Mechanical Properties of Chitosan-graft Maleic Anhydride Reinforced with Montmorillonite

    Science.gov (United States)

    Fajrin, A.; Sari, L. A.; Rahmawati, N.; Saputra, O. A.; Suryanti, V.

    2017-02-01

    The research aims to develop biodegradable composites as bio-based plastics from chitosan. The composites were prepared via solution casting method by introducing the maleic anhydride (MAH) as grafting agent and montmorillonite (MMt) as reinforcement. The grafting process of chitosan was conducted by varying concentrations of MAH which were 10, 20, and 30% w/w. It was observed that the chitosan-graft-maleic anhydride (Cs-g-MAH) containing 10% w/w of MAH increased its tensile strength by 70%. Reinforcement material was added to the Cs-g-MAH by varying MMt concentrations, e.g. 3, 6, 9 and 12% w/w. It was noted that the presence of 9% w/w of MMt in the Cs-g-MAH gave the best mechanical properties of the Cs-g-MAH/MMt composite.

  6. Polishing methods for metallic and ceramic transmission electron microscopy specimens: Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Kestel, B.J.

    1986-03-01

    In recent years, the increasing sophistication of transmission electron microscope (TEM) studies of materials has necessitated more exacting methods of specimen preparation. The present report describes improved equipment and techniques for electropolishing and chemically polishing a wide variety of specimens. Many of the specimens used in developing or improving the techniques to be described were irradiated with heavy ions such as nickel or vanadium to study radiation damage. The high cost of these specimens increased the need for reproducible methods of initial preparation postirradiation processing, and final thinning for TEM examination. A technique was also developed to salvage specimens that had previously been thinned but were unusable for various reasons. Jet polishing is, in general, the method of choice for surface polishing, sectioning, and thinning. The older beaker electropolishing method is included in this report because it is inexpensive and simple, and gives some insight into how the more recent methods were developed.

  7. Forming a health culture of future teachers in Polish educational establishments

    Directory of Open Access Journals (Sweden)

    IERMAKOVA T.S.

    2014-10-01

    Full Text Available Aim: to study the experience of the structure and system of training of future teachers in Polish schools. Material: content analysis of domestic and foreign authors. Used data from the survey of students of Polish universities. Also were used survey results through polish service ANKIETKA. For comparison, a questionnaire survey 35 students of the Faculty of Physical Education (future teachers of physical training and 30 students - the future teachers of elementary school of Ukrainian university. Results: the study of Polish teachers consider health culture of a person as the ability to assess individual and community health needs using in everyday life hygiene and health regulations. There have been some differences among Ukrainian and Polish students in their health and health culture. Among the respondents, Polish students - the future teachers of physical culture, is dominated motives such as the improvement of the physical condition, strengthen self-esteem, as well as improved health. Polish students from other disciplines believe that the most important motive for the adoption of physical activity is a concern for the physical well-being and mental health. The majority of Ukrainian students (future teachers of physical culture believe an important part of building health culture of their direct participation in various sports clubs, as well as the ability to organize physical culture, sports and educational work with students outside the classroom. Ukrainian students (other specialty noted the need to improve health, enhance knowledge in specific subjects humanities and promoting healthy lifestyles. Conclusions: It is recommended to use the experience of preparing students of Polish schools in modern Ukrainian higher education.

  8. Porous poly(D,L-lactic acid) foams with tunable structure and mechanical anisotropy prepared by supercritical carbon dioxide.

    Science.gov (United States)

    Floren, Michael; Spilimbergo, Sara; Motta, Antonella; Migliaresi, Claudio

    2011-11-01

    The design and tunability of tissue scaffolds, such as pore size and geometry, is crucial to the success of an engineered tissue replacement. Moreover, the mechanical nature of a tissue scaffold should display properties similar to the tissue of interest; therefore, tunability of the foam mechanical properties is desirable. Polymeric foams prepared using supercritical carbon dioxide as a blowing agent has emerged in recent years as a promising technique to prepare porous scaffolds. While a number of groups have reported on the tailoring of scaffold morphologies by using gas foaming techniques, few have considered the effects of such processing conditions on the physical and mechanical anisotropy achieved. The aim of this study was to demonstrate the tunability of the structure and mechanical anisotropy of foams prepared using a variety of different gas foaming conditions. Porous poly(D,L lactic acid) foams were prepared by the systematic adjustment of processing conditions, namely pressure, temperature and venting time, resulting in an extensive range of scaffold morphologies. Characterization of sample anisotropy was achieved by mechanical evaluation of foam specimens both longitudinal and transverse to the foaming direction. The obtained mechanical properties demonstrated a strong dependence of the processing conditions on mechanical anisotropy and performance. Furthermore, results indicate that factors other than pore geometry may be necessary to define the mechanical behavior of the foam specimens. The favorable compressive moduli, coupled with large degrees of anisotropy, suggests these foams may have suitable application as scaffolds for bone tissue engineering.

  9. Standards of the Polish Ultrasound Society - update. Sonomammography examination.

    Science.gov (United States)

    Jakubowski, Wiesław; Dobruch-Sobczak, Katarzyna; Migda, Bartosz

    2012-09-01

    The use of BIRADS classification has been recommended in sonomammography examinations in Poland since the year 2010. It was developed by the Polish Ultrasound Society and published in Ultrasound Examinations Standards of the Polish Ultrasound Society. Standards, based on BIRADS-usg classification, introduced uniformity in breast ultrasound examination descriptions and in the terminology of pathological lesions in breasts. BIRADS-usg classification takes into account breast morphological structure elements and pathological focal lesions in them. It enables the distinction between benign lesions and lesions suspected of being malignant. It contains information on the malignancy risk of focal lesions and proposals of diagnostic-therapeutic algorithms (including biopsy) in relation to lesions of different character. The Polish Ultrasound Society recommends performing prophylactic sonomammography examinations every 12 months in women over the age of 30 because of the increasing breast cancer morbidity in women from all age groups. In this article a spectrum of focal changes in breasts are presented within the relevant BIRADS-usg classification categories. The features of ultrasound morphology, enabling them to be classified to particular categories of BIRADS-usg classification are discussed. Management algorithms which may help clinicians to diagnose breast cancer and to treat it are proposed. Elements of medical history, physical examination, recommended techniques of sonomammography examination performance, technical parameters of ultrasound machine and examination description standards are presented. This article was prepared based on the Ultrasound Examination Standards of the Polish Ultrasound Society which was published in 2011 and updated. It contains numerous pictures visualizing BIRADS-usg classification.

  10. Standards of the Polish Ultrasound Society – update. Sonomammography examination

    Science.gov (United States)

    Jakubowski, Wiesław; Migda, Bartosz

    2012-01-01

    The use of BIRADS classification has been recommended in sonomammography examinations in Poland since the year 2010. It was developed by the Polish Ultrasound Society and published in Ultrasound Examinations Standards of the Polish Ultrasound Society. Standards, based on BIRADS-usg classification, introduced uniformity in breast ultrasound examination descriptions and in the terminology of pathological lesions in breasts. BIRADS-usg classification takes into account breast morphological structure elements and pathological focal lesions in them. It enables the distinction between benign lesions and lesions suspected of being malignant. It contains information on the malignancy risk of focal lesions and proposals of diagnostic-therapeutic algorithms (including biopsy) in relation to lesions of different character. The Polish Ultrasound Society recommends performing prophylactic sonomammography examinations every 12 months in women over the age of 30 because of the increasing breast cancer morbidity in women from all age groups. In this article a spectrum of focal changes in breasts are presented within the relevant BIRADS-usg classification categories. The features of ultrasound morphology, enabling them to be classified to particular categories of BIRADS-usg classification are discussed. Management algorithms which may help clinicians to diagnose breast cancer and to treat it are proposed. Elements of medical history, physical examination, recommended techniques of sonomammography examination performance, technical parameters of ultrasound machine and examination description standards are presented. This article was prepared based on the Ultrasound Examination Standards of the Polish Ultrasound Society which was published in 2011 and updated. It contains numerous pictures visualizing BIRADS-usg classification. PMID:26673579

  11. Convergent polishing: a simple, rapid, full aperture polishing process of high quality optical flats & spheres.

    Science.gov (United States)

    Suratwala, Tayyab; Steele, Rusty; Feit, Michael; Dylla-Spears, Rebecca; Desjardin, Richard; Mason, Dan; Wong, Lana; Geraghty, Paul; Miller, Phil; Shen, Nan

    2014-12-01

    Convergent Polishing is a novel polishing system and method for finishing flat and spherical glass optics in which a workpiece, independent of its initial shape (i.e., surface figure), will converge to final surface figure with excellent surface quality under a fixed, unchanging set of polishing parameters in a single polishing iteration. In contrast, conventional full aperture polishing methods require multiple, often long, iterative cycles involving polishing, metrology and process changes to achieve the desired surface figure. The Convergent Polishing process is based on the concept of workpiece-lap height mismatch resulting in pressure differential that decreases with removal and results in the workpiece converging to the shape of the lap. The successful implementation of the Convergent Polishing process is a result of the combination of a number of technologies to remove all sources of non-uniform spatial material removal (except for workpiece-lap mismatch) for surface figure convergence and to reduce the number of rogue particles in the system for low scratch densities and low roughness. The Convergent Polishing process has been demonstrated for the fabrication of both flats and spheres of various shapes, sizes, and aspect ratios on various glass materials. The practical impact is that high quality optical components can be fabricated more rapidly, more repeatedly, with less metrology, and with less labor, resulting in lower unit costs. In this study, the Convergent Polishing protocol is specifically described for fabricating 26.5 cm square fused silica flats from a fine ground surface to a polished ~λ/2 surface figure after polishing 4 hr per surface on a 81 cm diameter polisher.

  12. Grinding and polishing instead of sectioning for the tissue samples with a graft: Implications for light and electron microscopy.

    Science.gov (United States)

    Mukhamadiyarov, Rinat A; Sevostyanova, Victoria V; Shishkova, Daria K; Nokhrin, Andrey V; Sidorova, Olga D; Kutikhin, Anton G

    2016-06-01

    A broad use of the graft replacement requires a detailed investigation of the host-graft interaction, including both histological examination and electron microscopy. A high quality sectioning of the host tissue with a graft seems to be complicated; in addition, it is difficult to examine the same tissue area by both of the mentioned microscopy techniques. To solve these problems, we developed a new technique of epoxy resin embedding with the further grinding, polishing, and staining. Graft-containing tissues prepared by grinding and polishing preserved their structure; however, sectioning frequently required the explantation of the graft and led to tissue disintegration. Moreover, stained samples prepared by grinding and polishing may then be assessed by both light microscopy and backscattered scanning electron microscopy. Therefore, grinding and polishing outperform sectioning when applied to the tissues with a graft.

  13. Anisotropy of mechanical and thermal properties of AZ31 sheets prepared using the ARB technique

    Science.gov (United States)

    Halmešová, K.; Trojanová, Z.; Džugan, J.; Drozd, Z.; Minárik, P.; Knapek, M.

    2017-07-01

    In the accumulative roll bonding (ARB) technique, repeated stacking of material followed by conventional roll-bonding is carried out. For this process the surfaces are cleaned with ethanol and then joined together by rolling. The rolled material is then cut into two halves, again surface treated and roll-bonded. This process may be repeated several times. For the magnesium alloy AZ31 (Mg-3Al-1Zn) rolling at an elevated temperature of 400 °C is necessary for ARB because of the low plasticity of hexagonal magnesium alloys at lower temperatures. Samples for this study were prepared using 1 to 3 ARB passes through the rolling mill. It was found that the ARB substantially refined the grain size of sheets to the micrometer scale. The microstructure and texture of the deformed samples were studied by light and electron microscopy. The mechanical properties of the ARB samples were explored using tensile test-pieces cut from the sheets with the tensile axis taken either parallel or perpendicular to the rolling direction, where a significant anisotropy in both mechanical properties and Young’s modulus was found. Anisotropy is explained on the basis of the specific microstructure and texture formed during the ARB process.

  14. Thermal and dynamic mechanical characterization of thermoplastic polyurethane/organoclay nanocomposites prepared by melt compounding

    Energy Technology Data Exchange (ETDEWEB)

    Barick, A.K., E-mail: akbarick@gmail.com [Rubber Technology Centre, Indian Institute of Technology, Kharagpur 721302, West Bengal (India); Tripathy, D.K., E-mail: dkt@rtc.iitkgp.ernet.in [Rubber Technology Centre, Indian Institute of Technology, Kharagpur 721302, West Bengal (India)

    2010-01-15

    Thermoplastic polyurethane (TPU) nanocomposites based on organically modified layered silicate (OMLS) were prepared by melt intercalation process followed by compression molding. Different percentage of organoclays was incorporated into the TPU matrix in order to examine the influence of the nanoscaled fillers on nanostructure morphology and material properties. The microscopic morphology of the nanocomposites was evaluated by wide angle X-ray diffraction (WAXD), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The observation revealed that both nanoclay-polymer interactions and shear stress developed during melt mixing are responsible for the effectively organoclay dispersion in TPU matrix resulting intercalated/exfoliated morphology. Thermal stability of the nanocomposites measured by thermogravimetric analysis (TGA) was improved significantly with the addition of nanoclay. The differential scanning calorimetry (DSC) analysis reveals that melting point of the nanocomposites increased with incorporation of nanoclay. The dynamic mechanical properties of the TPU nanocomposites were analyzed using a dynamic mechanical thermal analyzer (DMTA), which indicates that the storage modulus (E'), loss modulus (E''), and glass transition temperature (T{sub g}) are significantly increased with increasing nanoclay content.

  15. Surface contamination by smearing during polishing - A PIXE study

    Energy Technology Data Exchange (ETDEWEB)

    Franklyn, C.B. E-mail: franklyn@aec.co.za; Merkle, R.K.W

    2001-07-01

    Preparation of samples for PIXE analysis follows standard procedures in order to present a smooth, uniform surface for microscopic investigation and analysis. Reports on the quality of the surface preparation are scant. We report on investigations of preparation of metallic samples for micro-probe analysis. These samples are metal strips of typically 0.5 mm width and 10-15 mm length, sandwiched between natural pyrite crystals and quartz glass, mounted in epoxy resin. The surface was polished using diamond abrasives. The smearing of metallic Ag, Au and Cu was investigated and was found to be most prevalent for Cu, but also clearly detectable for Ag and Au. The potential influence of beam halo and beam scattering in the resin mount appears to be negligible, but the results imply additional, as yet unidentified, factors besides smearing to explain all observations.

  16. Preparation, Characterization, and Mechanism for Biodegradable and Biocompatible Polyurethane Shape Memory Elastomers.

    Science.gov (United States)

    Chien, Yu-Chun; Chuang, Wei-Tsung; Jeng, U-Ser; Hsu, Shan-Hui

    2017-02-15

    Thermally induced shape memory is an attractive feature of certain functional materials. Among the shape memory polymers, shape memory elastomers (SMEs) especially those with biodegradability have great potential in the biomedical field. In this study, we prepared waterborne biodegradable polyurethane SME based on poly(ε-caprolactone) (PCL) oligodiol and poly(l-lactic acid) (PLLA) oligodiol as the mixed soft segments. The ratio of the soft segments in polyurethanes was optimized for shape memory behavior. The thermally induced shape memory mechanism of the series of polyurethanes was clarified using differential scanning calorimeter (DSC), X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS). In particular, the in situ SAXS measurements combined with shape deformation processes were employed to examine the stretch-induced (oriented) crystalline structure of the polyurethanes and to elucidate the unique mechanism for shape memory properties. The polyurethane with optimized PLLA crystalline segments showed a diamond-shape two-dimensional SAXS pattern after being stretched, which gave rise to better shape fixing and shape recovery. The shape memory behavior was further tested in 37 °C water. The biodegradable polyurethane comprising 38 wt % PCL segments and 25 wt % PLLA segments and synthesized at a relatively lower temperature by the waterborne procedure showed ∼100% shape recovery in 37 °C water. The biodegradable polyurethane SME also demonstrated good endothelial cell viability as well as low platelet adhesion/activation. We conclude that the waterborne biodegradable polyurethane SME possesses a unique thermally induced shape memory mechanism and may have potential applications in making shape memory biodegradable stents or scaffolds.

  17. THERMAL, MECHANICAL, AND MOISTURE ABSORPTION PROPERTIES OF WOOD-TiO2 COMPOSITES PREPARED BY A SOL-GEL PROCESS

    OpenAIRE

    Xiaoqing Wang; Junliang Liu,; Yubo Chai

    2012-01-01

    Wood-TiO2 (titania) composites were prepared by a sol-gel process, in which wood was impregnated with the precursor solutions prepared from tetrabutyl titanate (TBT), followed by a curing step. The surface morphology and moisture absorption behavior of the wood composites, as well as their thermal and mechanical performances, were examined. Environmental scanning electron microscopy (ESEM) analysis revealed that TiO2 gels were deposited principally in the cell lumens and partly in the cell wa...

  18. Structural evolution and magnetic properties of nanocrystalline 50 Permalloy powders prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Gheisari, Kh., E-mail: khgheisari@scu.ac.ir [Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University, Ahvaz (Iran, Islamic Republic of); Shahriari, Sh. [Department of Materials Science and Engineering, Islamic Azad University of Ahvaz, Ahvaz (Iran, Islamic Republic of); Javadpour, S. [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of)

    2013-10-15

    Highlights: •Nanocrystalline 50 Permalloy powders were prepared by mechanical alloying. •In addition to the nonuniform lattice strain, a uniform lattice strain was observed. •A good combination of M{sub s} (∼150 emu/g) and H{sub c} (∼0.13 Oe) was obtained after 60 h of milling. •Curie temperature was estimated to be ∼600 °C. -- Abstract: FeNi-based alloys commonly called Permalloys are interesting in their applications as soft magnetic materials with low coercivity and high permeability. In this study, nanocrystalline Fe–50 wt.% Ni alloy powders were prepared using a planetary ball mill at different milling times. The evolution of the microstructure and magnetic properties during the milling process were studied by the X-ray diffraction technique, the scanning electron microscope, the transmission electron microscope and the vibrating sample magnetometer. The results indicate that in the course of ball milling the Fe and Ni mixture, nanocrystalline FCC γ-(Fe, Ni) phase with the average crystallite size of 15 nm, particle size of 39 μm, nonuniform lattice strain of 0.45% and lattice parameter of 0.36062 nm formed after 24 h milling time. Although the crystallite size of the as-synthesized Permalloy powder is smaller than the magnetic exchange length, a low coercivity as expected from Herzer’s random anisotropy model is not observed. Among the different reasons, residual stress, γ-(Fe, Ni) phase formation and contamination are suggested as possible causes, which affect both coercivity and saturation magnetization.

  19. Preparation and formation mechanisms of metallic particles with controlled size, shape, structure and surface functionality

    Science.gov (United States)

    Lu, Lu

    Due to their excellent conductivity and chemical stability, particles of silver (Ag), gold (Au), copper (Cu) and their alloys are widely used in the electronic industry. Other unique properties extend their uses to the biomedical, optical and catalysis fields. All of these applications rely on particles with well controlled size, morphology, structure, and surface properties. Chemical precipitation from homogeneous solutions was selected as the synthetic route for the investigations described in this work. Based on the evaluation of key process parameters (temperature, reactant concentrations, reactant addition rate, mixing, etc.) the general formation mechanisms of metallic particles in various selected precipitation systems were investigated and elucidated. Five different systems for preparing particles with controlled size, morphology, structure and surface functionality are discussed. The first system involves the precipitation of Ag nanoparticles with spherical and anisotropic (platy or fiber-like) morphology. It will be shown that the formation of a stable Ag/Daxad complex has a significant impact on the reaction kinetics, and that the chromonic properties of Daxad molecules are responsible for the particle anisotropy. In the second system, Au-Ag core-shell nanoparticles were prepared in aqueous solution by a two-step precipitation process. The optical properties of these particles can be tailored by varying the thickness of the Ag shell. It was also determined that the stability of the bimetallic metallic sols depends on the Cl-ion concentration in solution. The third system discussed deals with preparation by the polyol process of well dispersed Cu nanospheres with high crystallinity and excellent oxidation resistance. We show that the heterogeneous nucleation (seeding) approach has significant merit in controlling particle size and uniformity. The functionalization of Au nanoparticle surfaces with glutathione molecules is discussed in the next section. The

  20. Advanced ion exchange resins for PWR condensate polishing

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, B. [Rohm and Haas Co. (United States); Tsuzuki, S. [Rohm and Haas Co. (Japan)

    2002-07-01

    The severe chemical and mechanical requirements of a pressurized water reactor (PWR) condensate polishing plant (CPP) present a major challenge to the design of ion exchange resins. This paper describes the development and initial operating experience of improved cation and anion exchange resins that were specifically designed to meet PWR CPP needs. Although this paper focuses specifically on the ion exchange resins and their role in plant performance, it is also recognized and acknowledged that excellent mechanical design and operation of the CPP system are equally essential to obtaining good results. (authors)

  1. Polishing X-ray Mirror Mandrel

    Science.gov (United States)

    1999-01-01

    NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery, and materials to replicate electro-formed nickel mirrors. The process allows fabricating precisely shaped mandrels to be used and reused as masters for replicating high-quality mirrors. MSFC's Space Optics Manufacturing Technology Center (SOMTC) has grinding and polishing equipment ranging from conventional spindles to custom-designed polishers. These capabilities allow us to grind precisely and polish a variety of optical devices, including x-ray mirror mandrels. This image shows Charlie Griffith polishing the half-meter mandrel at SOMTC.

  2. New Environmental Practices in Polish Production Firms

    DEFF Research Database (Denmark)

    Kræmer, Trine Pipi

    2002-01-01

    Based on five case studies in Poland, the paper discusses, how a specific environmental policy influences the firms? industrial environmental practices. The study illustrates, how the Polish environmental policy, dominated by environmental charges on emissions, is extremely effective in improving...

  3. Polish women's experiences of breastfeeding in Ireland.

    Science.gov (United States)

    Szafranska, Marcelina; Gallagher, Louise

    2016-01-01

    Exclusive breastfeeding among Polish mothers at three-four months (38.6 per cent) is in keeping with the low rates of breastfeeding in Ireland overall (Begley et al 2008), and suggests that Polish women have begun to adopt the infant feeding practices of Irish women. Therefore, the aim of this study was to explore the factors that influence Polish women's decisions to initiate and continue breastfeeding in Ireland. A descriptive qualitative approach was utilised to explore participants' perspectives of breastfeeding. Results showed that professional and family support are key to a successful breastfeeding experience for these mothers. Recommendations include further individualised support in order to meet the needs of Polish women breastfeeding in Ireland.

  4. Internet in Upbringing System of Polish Scouting

    Directory of Open Access Journals (Sweden)

    Jakub Czarkowski

    2011-01-01

    Full Text Available „Harcerstwo” is a Polish version of scouting, a unique result of fusing traditional scouting values with Polish national tradition, culture and patriotism. The main goal I set myself for this work was to define the place and role of Internet in the upbringing system used in Polish scouting and the function of media – Internet specifically – in determining the activities of scouts and guides within this system. The results of the study presented open the way for reflection upon the models of how a traditional educational (upbringing – parenting institution shouldoperate and the function of the Internet in such institutions. Using Polish Scouting and Guiding Association and its educational system as an example it provides answers for various questions concerning the place of education and traditional educational institutions in the future IT society, in which the role of Internet and other, even newer media, will unquestionably be significant and will largely determine the character of interpersonal relations.

  5. Productivity and soil properties 45 years after timber harvest and mechanical site preparation in western Montana

    Science.gov (United States)

    Luke M. Cerise; Deborah S. Page-Dumroese; Paul McDaniel; Cole Mayn; Robert. Heinse

    2013-01-01

    Site preparation following timber harvests is widely used to increase seedling establishment postharvest. Historically, dozer piling and ripping were the most common forms of site preparation in the Intermountain West. Less commonly, terracing of hill slopes was another form of site preparation on the Bitterroot National Forest in western Montana from 1961-1970 on...

  6. Experimental Polish-Lithuanian Corpus with the Semantic Annotation Elements

    Directory of Open Access Journals (Sweden)

    Danuta Roszko

    2015-06-01

    Full Text Available Experimental Polish-Lithuanian Corpus with the Semantic Annotation Elements In the article the authors present the experimental Polish-Lithuanian corpus (ECorpPL-LT formed for the idea of Polish-Lithuanian theoretical contrastive studies, a Polish-Lithuanian electronic dictionary, and as help for a sworn translator. The semantic annotation being brought into ECorpPL-LT is extremely useful in Polish-Lithuanian contrastive studies, and also proves helpful in translation work.

  7. Preparation, characterization and mechanical properties of microarc oxidation coating formed on titanium in Al(OH)3 colloidal solution

    Science.gov (United States)

    Li, Y.; Yao, B.; Long, B. Y.; Tian, H. W.; Wang, B.

    2012-04-01

    A ceramic coating with thickness of 20-70 μm was grown on titanium plate in Al(OH)3 colloidal solution by microarc oxidation (MAO) in constant current mode. It is found that the as-grown coating consists of rutile TiO2 phase together with a thin layer of Ai2TiO5 phase near the surface of the coating. After removing the Ai2TiO5 layer by polishing, a single phase of rutile TiO2 coating is achieved, which is different from results reported previously, where the coating is usually composed of two phases of rutile and anatase TiO2. It is suggested that the formation of the coating with single phase of rutile TiO2 is related to the existence of Al(OH)3 in the solution. The growth rate of the coating increases with increasing current density in the range of 17-23 A/dm2, but it increases little in the range of 23-30 A/dm2. The rutile TiO2 coating looks compactness and solidity in the coating grown in the density range of 17-23 A/dm2 but looseness and insubstantiality in the range of 23-30 A/dm2. The hardness and elastic modulus of the rutile TiO2 decreases with the density increasing. The mechanism of formation of the coating is discussed in the present work.

  8. Influence of Zn (II) ion on abrasive-free polishing of hard disk substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Hong, E-mail: hong_lei2005@163.com; Zhao, Rong, E-mail: zr890804@163.com; Chen, Ruling, E-mail: chen_ruling@163.com

    2014-07-01

    With higher requirement setting for hard disk substrate to minimize roughness and defects of the polished surface, abrasive-free polishing (AFP) of hard disk substrate has been put forward in this paper. The effect of Zn (II) ion on the AFP of hard disk substrate in the H{sub 2}O{sub 2} based slurry was investigated by AFP tests. The results indicate that the material removal rate of hard disk substrate polished in slurry with Zn (II) ion is obviously higher than that without Zn (II) ion. And surface polished by slurry containing Zn (II) ion exhibits lower surface roughness and fewer nano-asperity peaks than that without Zn (II) ion. Furthermore, the acting mechanism of Zn (II) ion in AFP of hard disk substrate was analyzed. X-ray photoelectron spectroscopy analysis shows that metal Zn appears on the polished surface, implying the tribochemistry reaction occurs during AFP. The electrochemical reaction between metal Zn and oxide film Ni{sub 2}O{sub 3} on the surface of hard disk substrate during AFP can promote the chemical effect in AFP and lead to the increasing of material removal rate. - Highlights: • Zn (II) ion improves surface quality in abrasive-free polishing (AFP). • The removal rate increases with the increasing of Zn (II) ion content. • Tribo-chemistry reaction exists during AFP. • Zn (II) ion accelerates the electrochemistry reaction during AFP.

  9. Surface morphology changes of acrylic resins during finishing and polishing phases

    Directory of Open Access Journals (Sweden)

    Glaucio Serra

    2013-12-01

    Full Text Available INTRODUCTION: The finishing and polishing phases are essential to improve smoothness and shining on the surface of acrylic resins used to make removable orthodontic appliances. A good surface finishing reduces roughness, which facilitates hygiene, prevents staining and provides greater comfort to the patients. OBJECTIVE: The aim of this paper was to analyze the changes on surface morphology of acrylic resins during finishing and polishing phases. METHODS: Thirty discs (10 mm in diameter and 5 mm in length were made with acrylic resin and randomly divided into ten groups. The control group did not receive any treatment while the other groups received gradual finishing and polishing. The last group received the entire finishing and polishing procedures. Surface morphology was qualitatively analyzed through scanning electron microscopy and quantitatively analyzed through a laser profilometer test. RESULTS: The acrylic resin surfaces without treatment showed bubbles which were not observed in the subsequent phases. Wearing out with multilaminated burs, finishing with wood sandpaper and finishing with water sandpaper resulted in surfaces with decreasing irregularities. The surfaces that were polished with pumice and with low abrasive liquids showed high superficial smoothness. CONCLUSION: Highly smooth acrylic resin surfaces can be obtained after mechanical finishing and polishing performed with multilaminated burs, wood sandpaper, water sandpaper, pumice and low abrasive liquids.

  10. Optimization of Polishing Parameters with Taguchi Method for LBO Crystal in CMP

    Institute of Scientific and Technical Information of China (English)

    Jun Li; Yongwei Zhu; Dunwen Zuo; Yong Zhu; Chuangtian Chen

    2009-01-01

    Chemical mechanical polishing (CMP) was used to polish Lithium triborate (UB_3O_5 or LBO) crystal. Taguchi method was applied for optimization of the polishing parameters. Material removal rate (MRR) and surface roughness are considered as criteria for the optimization. The polishing pressure, the abrasive concentration and the table velocity are important parameters which influence MRR and surface roughness in CMP of LBO crystal. Experiment results indicate that for MRR the polishing pressure is the most significant polishing parameter followed by table velocity; while for the surface roughness, the abrasive concentration is the most important one. For high MRR in CMP of LBO crystal the optimal conditions are: pressure 620 g/cm~2, concentration 5.0 wt pct, and velocity 60 r/min, respectively. For the best surface roughness the optimal conditions are: pressure 416 g/cm~2, concentration 5.0 wt pct, and velocity 40 r/min, respectively. The contributions of individual parameters for MRR and surface roughness were obtained.

  11. Laser polishing of additive manufactured Ti alloys

    Science.gov (United States)

    Ma, C. P.; Guan, Y. C.; Zhou, W.

    2017-06-01

    Laser-based additive manufacturing has attracted much attention as a promising 3D printing method for metallic components in recent years. However, surface roughness of additive manufactured components has been considered as a challenge to achieve high performance. In this work, we demonstrate the capability of fiber laser in polishing rough surface of additive manufactured Ti-based alloys as Ti-6Al-4V and TC11. Both as-received surface and laser-polished surfaces as well as cross-section subsurfaces were analyzed carefully by White-Light Interference, Confocal Microscope, Focus Ion Beam, Scanning Electron Microscopy, Energy Dispersive Spectrometer, and X-ray Diffraction. Results revealed that as-received Ti-based alloys with surface roughness more than 5 μm could be reduce to less than 1 μm through laser polishing process. Moreover, microstructure, microhardness and wear resistance of laser-polished zone was investigated in order to examine the thermal effect of laser polishing processing on the substrate of additive manufactured Ti alloys. This proof-of-concept process has the potential to effectively improve the surface roughness of additive manufactured metallic alloy by local polishing method without damage to the substrate.

  12. Conformal polishing approach: Tool footprint analysis

    Directory of Open Access Journals (Sweden)

    José A Dieste

    2016-02-01

    Full Text Available Polishing process is one of the most critical manufacturing processes during a metal part production because it determines the final quality of the product. Free-form surface polishing is a handmade process with lots of rejected parts, scrap generation and time and energy consumption. Two different research lines are being developed: prediction models of the final surface quality parameters and an analysis of the amount of material removed depending on the polishing parameters to predict the tool footprint during the polishing task. This research lays the foundations for a future automatic conformal polishing system. It is based on rotational and translational tool with dry abrasive in the front mounted at the end of a robot. A tool to part concept is used, useful for large or heavy workpieces. Results are applied on different curved parts typically used in tooling industry, aeronautics or automotive. A mathematical model has been developed to predict the amount of material removed in function of polishing parameters. Model has been fitted for different abrasives and raw materials. Results have shown deviations under 20% that implies a reliable and controllable process. Smaller amount of material can be removed in controlled areas of a three-dimensional workpiece.

  13. Influences of polishing on return loss of optical fiber connectors

    Institute of Scientific and Technical Information of China (English)

    DUAN Ji-an; LIU De-fu; ZHONG Jue

    2005-01-01

    With Al2O3 and SiO2 as polishing medium, under different polishing conditions, e.g. with different polishing pressure, polishing time and polishing fluid, the influences of polishing treatment on the return loss of optical fiber connectors were investigated. The return loss of optical fiber connectors is 32 - 38 dB before polishing. The results show that dry polishing(i. e. no polishing fluid) with Al2O3 has less influence on return loss of optical fiber connectors, while dry polishing with SiO2 reduces return loss to about 20 dB because of the end-face of optical fiber contaminated. The wet polishing(i. e. using distilled water as polishing fluid) with Al2O3 or SiO2 can increase return loss to 45 -50 dB, but wet polishing with Al2 O3 may produce optical fiber undercut depth of 80 - 140 nm. Wet polishing with SiO2 should be preferentially selected for optical fiber connectors and polishing time should be controlled within 20 - 30 s.

  14. Interculutral Polish-Chinese QQing

    Directory of Open Access Journals (Sweden)

    Elżbieta Gajek

    2012-12-01

    Full Text Available Working in tandem with the use of information and communication technologies is well-known and frequently used as a method of supporting learning of foreign languages in authentic communication. It is based on a constructivist approach to teaching. In the reported case study Polish and Chinese students discussed in English preprepared topics. The work shows the potential of e-learning at the micro level, as the language and intercultural task is implemented into an academic course without modification of the objectives and learning outcomes of the course. Evaluation carried out at the end of the project indicates that both groups perceived the task as a significant linguistic, cultural and personal experience. They stressed the importance of sharing “culture for culture” as the partner culture was new for most of them. The ability to talk and respond to information which was often strange, from the point of view of their own culture, allowed for learning intercultural competence ̔in action’.

  15. Compound antimalarial ethosomal cataplasm: preparation, evaluation, and mechanism of penetration enhancement.

    Science.gov (United States)

    Shen, Shuo; Liu, Shu-Zhi; Zhang, Yu-Shi; Du, Mao-Bo; Liang, Ai-Hua; Song, Li-Hua; Ye, Zu-Guang

    2015-01-01

    Malaria is still a serious public health problem in some parts of the world. The problems of recurrence and drug resistance are increasingly more serious. Thus, it is necessary to develop a novel antimalarial agent. The objectives of this study were to construct a novel compound antimalarial transdermal nanosystem-ethosomal cataplasm, to investigate its characteristics and efficiency, and to systematically explore the penetration-enhancing mechanisms of ethosomal cataplasm. Artesunate-loaded ethosomes and febrifugine-loaded ethosomes were prepared, and their characteristics were evaluated. Drug-loaded ethosomes were incorporated in the matrix of cataplasm to form the compound antimalarial ethosomal cataplasm. With the help of ethosomal technology, the accumulated permeation quantity of artesunate significantly increased at 8 hours after administration, which was 1.57 times as much as that of conventional cataplasm. Soon after administration, the ethosomal cataplasm could make a large quantity of antimalarial drug quickly penetrate through skin, then the remaining drug in the ethosomal cataplasm could be steadily released. These characteristics of ethosomal cataplasm are favorable for antimalarial drugs to kill Plasmodium spp. quickly and prevent the resurgence of Plasmodium spp. As expected, the ethosomal cataplasm showed good antimalarial efficiency in this experiment. The negative conversion rates were 100% and the recurrence rates were 0% at all dosages. The mechanism of penetration enhancement of the ethosomal cataplasm was systematically explored using an optics microscope, polarization microscope, and transmission electron microscopy. The microstructure, ultrastructure, and birefringent structure in skin were observed. Data obtained in this study showed that the application of ethosomal technology to antimalarial cataplasm could improve the transdermal delivery of drug, enhance the efficacy, and facilitate practical application in clinic.

  16. The Effect of Grinding and Polishing Procedure of Tool Steels in Sheet Metal Forming

    DEFF Research Database (Denmark)

    Lindvall, F.; Bergström, J.; Krakhmalev, P.

    2010-01-01

    The surface finish of tools in sheet metal forming has a large influence on the performance of the forming tool. Galling, concern of wear in sheet metal forming, is a severe form of adhesive wear where sheet material is transferred on to the tool surface. By polishing the tools to a fine surface...... 40 and Vanadis 6 and up to ten different grinding and polishing treatments were tested against AISI 316 stainless steel. The tests showed that an optimum surface preparation might be found at the transition between abrasive and adhesive wear....

  17. Effects of surface polishing and annealing on the optical conductivity of intermetallic compounds

    CERN Document Server

    Rhee, J Y

    1999-01-01

    The optical conductivity spectra of several intermetallic compounds were measured by spectroscopic ellipsometry. Three spectra were measured for each compound; just after the sample was mechanically polished, at high temperature, and after the sample was annealed at 110 .deg. C for at least one day and cooled to room temperature. An equiatomic FeTi alloy showed the typical effects of annealing after mechanical polishing of surface. The spectrum after annealing had a larger magnitude and sharper structures than the spectrum before annealing. We also observed shifts of peaks in the spectrum. A relatively low-temperature annealing gave rise to unexpectedly substantial effects, and the effects were explained by recrystallization and/or a disorder -> order transition of the surface of the sample which was damaged and, hence, became highly disordered by mechanical polishing. Similar effects were also observed when the sample temperature was lowered. The observed changes upon annealing could partly be explained by p...

  18. Preparation by a Rheological Phase Reaction Method and Thermal Decomposition Reaction Mechanism of Nickelous Salicylate Tetrahydrate

    Institute of Scientific and Technical Information of China (English)

    WangJin-long; YuanLiang-jie; YangYi-yong; SunJu-tang; ZhangKe-li

    2003-01-01

    The single crystal nickel salicylate tetrahydrate was prepared with the rheological phase reaction method from nickelous hydroxide and salicylic acid. The crystal structure was determinecL It is monoclinic, space group P21/n, α=0.678 74(3), b=0. 515 91(2), c=2. 313 30(9) nm, β=90.9286(17)°,V=0. 809 94(6) nm3, Z=2, ρcalod =1. 661 g· cm-3. Final R indices: R=0. 027 9 and ωR=0.065 0[Ⅰ>2σ(Ⅰ)]. The thermal decomposition mechanism in an inert atmosphere was investigated via TG, DTG and DTA. The thermal decomposition products were characterized with IR and micro-powder X-ray diffraction method. A new coordination polymer ( NiC6 H4 O)n as an intermediate product and nanoscale metal nickel were obtained in the ranges of 364-429℃ and 429-680℃, respectively.

  19. Preparation of Barium Titanate Nanopowder through Thermal Decomposition of Peroxide Precursor and Its Formation Mechanism

    Institute of Scientific and Technical Information of China (English)

    PENG, Yangxi; CHEN, Qiyuan; LIU, Shijun

    2009-01-01

    H_2TiO_3 was dissolved in the mixture of hydrogen formed peroxide and ammonia under the pH range of 8-10 with a transparent yellow solution formed. When an equivalent mole of Ba~(2+) solution was added into the yellow solution, the precipitate produced was the peroxide precursor of barium titanate. The cubic nanopowder of barium titanate was obtained when the precipitate was washed, stoved, and then calcined at 600 ℃ for 1 h. The peroxide precursor of barium titanate and barium titanate nanopowder prepared were characterized to be BaTi(H_2O_2)_2O_3 by TGA-DTA, XRD, TEM, SEM, and XREDS. The peroxide precursor of barium titanate was determined to be BaTi(H_2O_2)_2O_3. The particle size of the barium titanate nanopowder, the calcined product of BaTi(H_2O_2)_2O_3, was in the range of 20-40 nm. A formation mechanism of the barium titanate nanopowder through thermal decomposition of its peroxide precursor was proposed and then validated.

  20. Molecular modeling, FTIR spectral characterization and mechanical properties of carbonated-hydroxyapatite prepared by mechanochemical synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Youness, Rasha A. [Spectroscopy Department, National Research Centre, El-Bohouth Str., 12622, Dokki, Giza (Egypt); Taha, Mohammed A. [Solid-State Physics Department, National Research Centre, El-Bohouth Str., 12622, Dokki, Giza (Egypt); Elhaes, Hanan [Physics Department, Faculty of Women for Arts, Science, and Education, Ain Shams University, 11757 Cairo (Egypt); Ibrahim, Medhat, E-mail: medahmed6@yahoo.com [Spectroscopy Department, National Research Centre, El-Bohouth Str., 12622, Dokki, Giza (Egypt)

    2017-04-01

    Nanocrystalline B-type carbonate substituted hydroxyapatite (B-CHA) powder has been successively synthesized by mechanochemical method. The effect of milling times on the formation of B-CHA was investigated by Fourier transform infrared spectroscopy, X-ray diffraction technique and scanning electron microscopy. Moreover, physical as well as mechanical properties were examined as a function of milling time. Furthermore, theoretical model was presented for hydroxyapatite (HA). Semiempirical calculations at PM6 level were used to calculate thermal parameters including entropy; enthalpy; heat capacity; free energy and heat of formation in the temperature range from 200 up to 500 k. The results revealed that single phase B-CHA was successfully formed after 8 h of milling when Ball to Powder Ratio (BPR) equals to 10:1. Results revealed that entropy; enthalpy and heat capacity gradually increased as a function of temperature while, free energy and heat of formation decreased with the increasing of temperature. Comparison with higher level of theory was conducted at HF and DFT using the models HF/3-21g**; B3LYP/6-31G(d,p) and B3LYP/LANL2DZ, respectively and indicated that PM6 could be utilized with appropriate accuracy and time to study physical and thermochemical parameters for HA. - Highlights: • Preparation of Nanocrystalline B-type carbonate substituted hydroxyapatite (B-CHA) powder by mechanochemical method. • Characterization of CHA. • Semiemperical and DFT models for CHA.

  1. Preparation and mechanical property of core-shell type chitosan/calcium phosphate composite fiber

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Atsushi [Japan Society for the Promotion of Science, Ikenohata1-1-1, Daitou-ku, Tokyo 110-0008 (Japan) and Creative Research Initiative ' Sousei' , Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan)]. E-mail: MATSUDA.Atsushi@nims.go.jp; Ikoma, Toshiyuki [Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Kobayashi, Hisatoshi [Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)]. E-mail: Kobayashi.Hisatoshi@nims.go.jp; Tanaka, Junzo [Creative Research Initiative ' Sousei' , Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan); Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)

    2004-12-01

    Core-shell type chitosan/calcium phosphate composite fibers were prepared by a facile wet spinning method; the chitosan aqueous solution with PO{sub 4} ions was dropped and coagulated in the ethanol/calcium hydroxide solutions at different mixed ratio. X-ray diffraction (XRD) patterns indicated that the crystal phases of calcium phosphates in the composite fibers were a low-crystalline hydroxyapatite (HAp; Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2})or the low-crystalline hydroxyapatite/brushite mixture depended on the ratio of ethanol/calcium hydroxide solutions. The inorganic contents were ca. 60 wt.% by using the TG-DTA analysis. The energy-dispersive X-ray spectroscopy (EDS) analysis indicated that Ca and P atoms were mainly distributed on the outer layer of the composite fiber to grow calcium phosphate crystals; however, a little amount of P atom still remained at the inside of the fiber. This indicated that the composite fibers formed a unique core-shell structure with shell of calcium phosphate and core of chitosan. The mechanical property of the fibers was reinforced by the initial concentration of chitosan solution.

  2. Reduction mechanism of Ni2+ into Ni nanoparticles prepared from different precursors: Magnetic studies

    Indian Academy of Sciences (India)

    R S Ningthoujam; N S Gajbhiye; Sachil Sharma

    2009-03-01

    The reduction mechanism of Ni2+ into Ni particles using different precursors such as NiCl2 solution, NiO powder and Ni[(NH3)6]Cl2 complex has been established. Different particle sizes can be designed from these precursors. The smallest crystallite size (12 nm) can be obtained from Ni[(NH3)6]Cl2 complex in the presence of the stabilizing ligand (oleic acid). The field-cooled (FC) and zero-field-cooled (ZFC) magnetization of Ni particles obtained from Ni[(NH3)6]Cl2 complex in the temperature range 5–300 K established the ferromagnetic interaction up to 300 K. The magnetization values at three different temperatures 5, 70 and 300 K are 50.2, 49.5 and 45.5 Oe respectively at 3 × 104 Oe applied field and such values are less than that of the bulk value. The Curie temperature (c) decreases slightly with the decrease of particle size. This study will provide guidance in the preparation of metal nanoparticles from different precursors.

  3. Structure and mechanical characterization of Mg-Nd-Zn alloys prepared by different processes

    Science.gov (United States)

    Dvorský, D.; Kubásek, J.; Vojtěch, D.; Voňavková, I.; Veselý, M.; Čavojský, M.

    2017-02-01

    Magnesium alloys containing about 3 wt. % of Nd and 0.5 wt. % of Zn are considered as promising materials for application in transport and medical industry. Properly treated materials can reach ultimate tensile strength (UTS) higher than 300 MPa. Also the corrosion resistance of these alloys is superior to many other magnesium-based materials. Present work is focused on the preparation of Mg-3Nd-0.5Zn magnesium alloy by classical casting and subsequent thermal treatment. As-cast material was extruded at 400 °C, with extrusion ratio equal to 16 and velocity of 0.2 mm/s. The effect of thermal treatment and also strong plastic deformation during extrusion on final structure conditions and mechanical properties is specified. Present results confirm significant improvement of tensile yield strength (TYS) and UTS after extrusion process as a consequence of fine-grained structure combined with precipitation strengthening. Beside, texture strengthening in the direction parallel to the extrusion has been observed too.

  4. Preparation of High Impermeable and Crack-resistance Chemical Admixture and Its Mechanism

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A kind of high impermeable and crack-resistance chemical admixture (HICRCA) was prepared, which is a compound chemical admixture composed of an expansion ingredient,density ingredient, and organic hydrophobic poreblocking ingredient. The results of the experiments indicate that the addition of HICRCA improves mortar and concrete in the following performances:(1) perfect workability: slump is more than 22cm, the slump after 3h is about 16cm; (2)high impermeability:for the mortar,the pervious height under a water pressure of 1.5MPa is 1.5cm,for the concrete, the pervious height under a water pressure of 5.0MPa is 2.2cm;(3)high crack-resistance:there is a micro-expansion at the age of 90d;(4)high compressivestrength:compared with the controlled concrete,the compressive strengths at the age of 3d and 28d are improved by 66.4% and 62.0%, respectively.At the same time,the effects of different curing condition on mortar and concrete expansive and shrinkage performance were studied.In addition,the impermeable and crack-resistance mechanism was investigated in the present paper.

  5. Preparation and characterization of mechanical properties of foam glass for artificial floating island carrier

    Directory of Open Access Journals (Sweden)

    Chenxi Zhai

    2015-06-01

    Full Text Available Base compositions of the foam glasses in this study include commercial silica, alumina, boric acid, sodium carbonate, potassium carbonate, carbon powder, and disodium hydrogen phosphate. The foam glasses with partial Na2O replaced by Li2O were prepared and investigated as a possible artificial floating island carrier of water purifying unit. The effects of Li2O dosage on the density, mechanical strengths, and microstructures were studied. Foam glass with 15 mol% Na2O replaced by Li2O displayed a good compressive strength, 3.582 MPa, while the bulk density was relatively low, about 0.398 g/cm3. The chemical stability of samples was evaluated with inductively coupled plasma atomic emission spectrometer, which showed low ion dissolution content in different pH dissolutions. The experimental results showed that the foam glass sample with 15 mol% Na2O replaced by Li2O exhibited excellent comprehensive properties, and the reason may contribute to the mixed alkali effect that proper amount of Li+ could impede the migration of large-radius ions like Na+ and K+ and thus could improve the glass network structure.

  6. Microstructure and mechanical properties of Zr-Si-N films prepared by rf-reactive sputtering

    CERN Document Server

    Nose, M; Zhou, M; Mae, T; Meshii, M

    2002-01-01

    ZrN and ZrSiN films were prepared in an rf sputtering apparatus that has a pair of targets facing each other (referred to as the facing target--type rf sputtering). Films were deposited on silicon wafers without bias application or substrate heating in order to examine only the effect of silicon addition to the transition metal nitride films. The contents of zirconium, nitrogen, and silicon of the films were determined with an electron probe microanalyzer. The transmission electron microscopy studies were carried out in addition to x-ray diffraction. For the high resolution transmission electron microscopy observation, the field emission type transmission electron microscope was used, which provides a point-to-point resolution of 0.1 nm. The samples were observed both parallel and perpendicular to the film surface, which were plane and cross sectional views, respectively. In order to investigate the relationship between the mechanical properties and microstructure of films, the hardness was measured by a nano...

  7. The effect of polishing technique on 3-D surface roughness and gloss of dental restorative resin composites.

    Science.gov (United States)

    Ereifej, N S; Oweis, Y G; Eliades, G

    2013-01-01

    The aim of this study was to compare surface roughness and gloss of resin composites polished using different polishing systems. Five resin composites were investigated: Filtek Silorane (FS), IPS Empress Direct (IP), Clearfil Majesty Posterior (CM), Premise (PM), and Estelite Sigma (ES). Twenty-five disk specimens were prepared from each material, divided into five groups, each polished with one of the following methods: Opti1Step (OS), OptiDisc (OD), Kenda CGI (KD), Pogo (PG), or metallurgical polishing (ML). Gloss and roughness parameters (Sa, Sz, Sq, and St) were evaluated by 60°-angle glossimetry and white-light interferometric profilometry. Two-way analysis of variance was used to detect differences in different materials and polishing techniques. Regression and correlation analyses were performed to examine correlations between roughness and gloss. Significant differences in roughness parameters and gloss were found according to the material, type of polishing, and material/polishing technique (ppolishing procedure and the type of composite can have significant impacts on surface roughness and gloss of resin composites.

  8. Standards of the Polish Ultrasound Society - update. Spleen examination.

    Science.gov (United States)

    Walczyk, Joanna; Walas, Maria Krystyna

    2013-03-01

    Ultrasound scan of the spleen is an integral part of the overall abdominal examination. Due to its anatomical position, physical examination of the spleen is frequently supplemented with an ultrasound which plays a special role in the differential diagnostics of splenic diseases and facilitates the determination of further diagnostic and therapeutic procedures. Similarly to other types of ultrasound scans, the examiner should be familiar with all significant clinical information as well as results of examinations and tests conducted so far. This enables to narrow the scope of search for etiological factors and indicate specific disease entities in the findings as well as allows for accurate assessment of coexistent pathologies. The article presents the standards of the Polish Ultrasound Society concerning the apparatus, preparation for the examination, technique and description of the findings. The authors discuss the normal anatomy of the spleen and the most common pathologies ranging from splenomegaly to splenic traumas. The indications for the contrast-enhanced ultrasound and characteristic patterns of enhancement of individual focal lesions are presented. This article is supplemented with photographic documentation, which provides images of the discussed lesions. The ultrasound examination, if carried out in compliance with current standards, allows for accurate interpretation of detected changes. This article has been prepared on the basis of the Ultrasound Examination Standards of the Polish Ultrasound Society (2011) and updated with the current knowledge.

  9. Standards of the Polish Ultrasound Society – update. Spleen examination

    Science.gov (United States)

    Walas, Maria Krystyna

    2013-01-01

    Ultrasound scan of the spleen is an integral part of the overall abdominal examination. Due to its anatomical position, physical examination of the spleen is frequently supplemented with an ultrasound which plays a special role in the differential diagnostics of splenic diseases and facilitates the determination of further diagnostic and therapeutic procedures. Similarly to other types of ultrasound scans, the examiner should be familiar with all significant clinical information as well as results of examinations and tests conducted so far. This enables to narrow the scope of search for etiological factors and indicate specific disease entities in the findings as well as allows for accurate assessment of coexistent pathologies. The article presents the standards of the Polish Ultrasound Society concerning the apparatus, preparation for the examination, technique and description of the findings. The authors discuss the normal anatomy of the spleen and the most common pathologies ranging from splenomegaly to splenic traumas. The indications for the contrast-enhanced ultrasound and characteristic patterns of enhancement of individual focal lesions are presented. This article is supplemented with photographic documentation, which provides images of the discussed lesions. The ultrasound examination, if carried out in compliance with current standards, allows for accurate interpretation of detected changes. This article has been prepared on the basis of the Ultrasound Examination Standards of the Polish Ultrasound Society (2011) and updated with the current knowledge. PMID:26672802

  10. Standards of the Polish Ultrasound Society – update. Spleen examination

    Directory of Open Access Journals (Sweden)

    Joanna Walczyk

    2013-03-01

    Full Text Available Ultrasound scan of the spleen is an integral part of the overall abdominal examination. Due to its anatomical position, physical examination of the spleen is frequently supplemented with an ultrasound which plays a special role in the differential diagnostics of splenic diseases and facilitates the determination of further diagnostic and therapeutic procedures. Similarly to other types of ultrasound scans, the examiner should be familiar with all significant clinical information as well as results of examinations and tests conducted so far. This enables to narrow the scope of search for etiological factors and indicate specific disease entities in the findings as well as allows for accurate assessment of coexistent pathologies. The article presents the standards of the Polish Ultrasound Society concerning the apparatus, preparation for the examination, technique and description of the findings. The authors discuss the normal anatomy of the spleen and the most common pathologies ranging from splenomegaly to splenic traumas. The indications for the contrast-enhanced ultrasound and characteristic patterns of enhancement of individual focal lesions are presented. This article is supplemented with photographic documentation, which provides images of the discussed lesions. The ultrasound examination, if carried out in compliance with current standards, allows for accurate interpretation of detected changes. This article has been prepared on the basis of the Ultrasound Examination Standards of the Polish Ultrasound Society (2011 and updated with the current knowledge.

  11. HOMESCHOOLING IN POLAND? LEGAL STATUS AND ARGUMENTS USED IN POLISH DEBATE OVER HOME EDUCATION

    Directory of Open Access Journals (Sweden)

    Szymon Paciorkowski

    2014-08-01

    Full Text Available Purpose – the purpose of this article is to summarize the legal aspects of home education in Poland, with particular emphasis on the evolution of the provisions of the Polish School Education Act 1991 and selected jurisdiction of Polish administrative courts. Design/methodology/approach – research was based on the analysis of legislation, including legislation drafts, published studies and other scholarly works as well as published opinions. The scientific approach was based on investigating which legal aspects of homeschooling have raised most controversies and have been thoroughly discussed. Findings – the main findings of the research focus on presenting the evolution of the Polish education law regarding the issue of home education and the reactions – both from the legal doctrine and the practitioners of homeschooling – to changes of law. Practical aspects of implementation of the provisions were also shown on the examples of the verdicts of Polish administrative courts. Research limitations/implications – article is based on already published works, but it proves that a clear evolution of Polish government’s approach to home education can be observed. However, the adoption of more accurate and clear provisions does not mean that they are less restrictive, although the recent amendments remove some of the obligations. Practical implications - article may be helpful for scholars interested in analysis of the Polish regulations applied to the home based education, offering them a summarized history of regulations and a selection of publications devoted to this subject. At the same time it points to the necessity of preparing more unbiased publications pertaining to the matter. Originality/value - the article is has the form of literature review; it is mostly based on already published articles and selected verdicts. Its value lies in a summarized presentation of the direction of the evolution of Polish regulation considering home

  12. Influence of polishing procedures on the surface roughness of dental ceramics made by different techniques.

    Science.gov (United States)

    Oliveira-Junior, Osmir Batista; Buso, Leonardo; Fujiy, Fábio Hiroshi; Lombardo, Geraldo Henrique Leao; Campos, Fernanda; Sarmento, Hugo Ramalho; Souza, Rodrigo Othavio Assuncao

    2013-01-01

    The aim of this study was to evaluate the influence of 2 different surface polishing procedures-glazing and manual polishing-on the roughness of ceramics processed by computer-aided design/computer-aided manufacturing (CAD/CAM) and conventional systems (stratification technique). Eighty ceramic discs (diameter: 8 mm, thickness: 1 mm) were prepared and divided among 8 groups (n = 10) according to the type of ceramic disc and polishing method: 4 GZ and 4 MP. Specimens were glazed according to each manufacturer's recommendations. Two silicone polishing points were used on the ceramic surface for manual polishing. Roughness was measured using a surface roughness tester. The roughness measurements were made along a distance of 2 mm on the sample surface and the speed of reading was 0.1 mm/s. Three measurements were taken for each sample. The data (μm) were statistically analyzed using analysis of variance (ANOVA) and Tukey's test (α = 0.05). Qualitative analysis was performed using scanning electron microscopy (SEM). The mean (± SD) roughness values obtained for GZ were: 1.1 ± 0.40 μm; 1.0 ± 0.31 μm; 1.6 ± 0.31 μm; and 2.2 ± 0.73 μm. For MP, the mean values were: 0.66 ± 0.13 μm; 0.43 ± 0.14 μm; 1.6 ± 0.55 μm; and 2.0 ± 0.63 μm. The mean roughness values were significantly affected by the ceramic type (P = 0.0001) and polishing technique (P = 0.0047). The SEM images confirmed the roughness data. The manually polished glass CAD/CAM ceramics promoted lower surface roughness than did the glazed feldspathic dental ceramics.

  13. The coercivity mechanism of Pr–Fe–B nanoflakes prepared by surfactant-assisted ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Wen-Liang, E-mail: wlzuo@iphy.ac.cn; Zhang, Ming; Niu, E.; Shao, Xiao-Ping; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen, E-mail: shenbg@aphy.iphy.ac.cn

    2015-09-15

    The strong (00l) textured Pr{sub 12+x}Fe{sub 82−x}B{sub 6} (x=0, 1, 2, 3, 4) nanoflakes with high coercivity were prepared by surfactant-assisted ball milling (SABM). The thickness and length of the flakes are mainly in the range of 50−200 nm and 0.5−2 μm, respectively. A coercivity of 4.16 kOe for Pr{sub 15}Fe{sub 79}B{sub 6} nanoflakes was obtained, which is the maximum coercivity of R{sub 2}Fe{sub 14}B (R=Pr, Nd) nanoflakes or nanoparticles reported up to now. The results of XRD and SEM for the aligned Pr{sub 15}Fe{sub 79}B{sub 6} nanoflakes indicate that a strong (00l) texture is obtained and the easy magnetization direction is parallel to the surface of the flakes. The angular dependence of coercivity for aligned sample indicates that the coercivity mechanism of the as-milled nanoflakes is mainly dominated by domain wall pinning. Meanwhile, the field dependence of coercivity, isothermal (IRM) and dc demagnetizing (DCD) remanence curves also indicate that the coercivity is mainly determined by domain wall pinning, and nucleation also has an important effect. In addition, the mainly interaction of flakes is dipolar coupling. The research of coercivity mechanism for Pr{sub 15}Fe{sub 79}B{sub 6} nanoflakes is important for guidance the further increase its value, and is useful for the future development of the high performance nanocomposite magnets and soft/hard exchange spring magnets. - Highlights: • A coercivity of 4.16 kOe for Pr{sub 15}Fe{sub 79}B{sub 6} nanoflakes was obtained. • The strong (00l) textured is obtained for Pr{sub 15}Fe{sub 79}B{sub 6} nanoflakes. • The interaction of nanoflakes is mainly dipolar coupling. • Domain wall pinning is the mainly coercivity mechanism.

  14. Utilization of En Ac-42100 Cast Aluminum Alloy for Casting of Critical Components. I. Preparation and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Vanko Branislav

    2014-12-01

    Full Text Available Requirement on the minimum value of elongation for critical components is about 15 %. The research deals with the possibility of replacing the dendritic morphology of primary solid solution and brittle eutectic silicon plates with finer particles with a more suitable morphology and size, and the possibility of increasing the mechanical properties. Introduced first part is focused on the process of preparation of experimental material and mechanical properties.

  15. Internet Use of Polish by Polish Melburnians: Implications for Maintenance and Teaching

    Science.gov (United States)

    Fitzgerald, Michael; Debski, Robert

    2006-01-01

    The Internet has become an important communication medium and it is having a significant impact on language use. The present study takes a "snapshot" of how the Polish language is currently used with modern communications technologies by Polish-Australians living in Melbourne. Through a questionnaire, it surveys which communications…

  16. Morphology, thermal and mechanical properties of PVC/MMT nanocomposites prepared by solution blending and solution blending + melt compounding

    DEFF Research Database (Denmark)

    Madaleno, Liliana Andreia Oliveira; Schjødt-Thomsen, Jan; Pinto, José Cruz

    2010-01-01

    and solution blending + melt compounding The effects on morphology, thermal and mechanical properties of the PVC/MMT nanocomposites were studied by varying the amount of Na-MMT and OMMT in both methods SEM and XRD analysis revealed that possible intercalated and exfoliated structures were obtained in all...... of the PVC/MMT nanocomposites Thermogravimetric analysis revealed that PVC/Na-MMT nanocomposites have better thermal stability than PVC/OMMT nanocomposites and PVC. In general, PVC/MMT nanocomposites prepared by solution blending + melt compounding revealed improved thermal properties compared to PVC....../MMT nanocomposites prepared by solution blending Vicar tests revealed a significant decrease in Vicar softening temperature of PVC/MMT nanocomposites prepared by solution blending + melt compounding compared to unfilled PVC The mechanical properties of the PVC/MMT nanocomposites were, in general, greatly improved...

  17. Microscopic view of osseointegration and functional mechanisms of implant surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Han, Guang; Shen, Zhijian, E-mail: shen@mmk.su.se

    2015-11-01

    Argon ion beam polishing technique was applied to prepare the cross sections of implants feasible for high resolution scanning electron microscope investigation. The interfacial microstructure between newly formed bone and implants with three modified surfaces retrieved after in vivo test using three different animal models was characterized. By this approach it has become possible to directly observe early bone formation, the increase of bone density, and the evolution of bone structure. The two bone growth mechanisms, distant osteogenesis and contact osteogenesis, can also be distinguished. These direct observations give, at microscopic level, a better view of osseointegration and expound the functional mechanisms of various implant surfaces for osseointegration. - Highlights: • Argon ion beam polishing was used for cross sections of interface. • The interfaces between new bone and implants can be distinguished. • Two bone growth mechanisms were verified. • The functional mechanisms of three modified implants were expounded.

  18. Effect of sintering conditions on the microstructural and mechanical characteristics of porous magnesium materials prepared by powder metallurgy.

    Science.gov (United States)

    Čapek, Jaroslav; Vojtěch, Dalibor

    2014-02-01

    There has recently been an increased demand for porous magnesium materials in many applications, especially in the medical field. Powder metallurgy appears to be a promising approach for the preparation of such materials. Many works have dealt with the preparation of porous magnesium; however, the effect of sintering conditions on material properties has rarely been investigated. In this work, we investigated porous magnesium samples that were prepared by powder metallurgy using ammonium bicarbonate spacer particles. The effects of the purity of the argon atmosphere and sintering time on the microstructure (SEM, EDX and XRD) and mechanical behaviour (universal loading machine and Vickers hardness tester) of porous magnesium were studied. The porosities of the prepared samples ranged from 24 to 29 vol.% depending on the sintering conditions. The purity of atmosphere played a significant role when the sintering time exceeded 6h. Under a gettered argon atmosphere, a prolonged sintering time enhanced diffusion connections between magnesium particles and improved the mechanical properties of the samples, whereas under a technical argon atmosphere, oxidation at the particle surfaces caused deterioration in the mechanical properties of the samples. These results suggest that a refined atmosphere is required to improve the mechanical properties of porous magnesium.

  19. Smoking characteristics of Polish immigrants in Dublin.

    LENUS (Irish Health Repository)

    Kabir, Zubair

    2008-01-01

    BACKGROUND: This study examined two main hypotheses: a) Polish immigrants\\' smoking estimates are greater than their Irish counterparts (b) Polish immigrants purchasing cigarettes from Poland smoke "heavier" (>\\/= 20 cigarettes a day) when compared to those purchasing cigarettes from Ireland. The study also set out to identify significant predictors of \\'current\\' smoking (some days and everyday) among the Polish immigrants. METHODS: Dublin residents of Polish origin (n = 1,545) completed a previously validated Polish questionnaire in response to an advertisement in a local Polish lifestyle magazine over 5 weekends (July-August, 2007). The Office of Tobacco Control telephone-based monthly survey data were analyzed for the Irish population in Dublin for the same period (n = 484). RESULTS: Age-sex adjusted smoking estimates were: 47.6% (95% Confidence Interval [CI]: 47.3%; 48.0%) among the Poles and 27.8% (95% CI: 27.2%; 28.4%) among the general Irish population (p < 0.001). Of the 57% of smokers (n = 345\\/606) who purchased cigarettes solely from Poland and the 33% (n = 198\\/606) who purchased only from Ireland, 42.6% (n = 147\\/345) and 41.4% (n = 82\\/198) were "heavy" smokers, respectively (p = 0.79). Employment (Odds Ratio [OR]: 2.89; 95% CI: 1.25-6.69), lower education (OR: 3.76; 95%CI: 2.46-5.74), and a longer stay in Ireland (>24 months) were significant predictors of current smoking among the Poles. An objective validation of the self-reported smoking history of a randomly selected sub-sample immigrant group, using expired carbon monoxide (CO) measurements, showed a highly significant correlation coefficient (r = 0.64) of expired CO levels with the reported number of cigarettes consumed (p < 0.0001). CONCLUSION: Polish immigrants\\' smoking estimates are higher than their Irish counterparts, and particularly if employed, with only primary-level education, and are overseas >2 years.

  20. Polish parliament liberalizes abortion law.

    Science.gov (United States)

    1996-11-22

    On October 24, the Sejm (Poland's lower house of parliament) voted 228 to 195 (with 16 abstentions) to amend Poland's March 1993 ban on abortions. The amendment legalizes abortion until the 12th week of pregnancy for women who face financial hardship or difficult personal circumstances. Client counseling by a doctor who will not perform the abortion and a 3-day wait are required. Abortions will be permitted in licensed private clinics, as well as in public hospitals. Anyone performing an illegal abortion can receive 2 years' imprisonment. The government will subsidize contraceptive pills, and a sex education curriculum will be developed for schools. Abortion had been legal and widely available under communist rule; however, a Catholic-aligned government limited abortion to cases where a woman's life or health was endangered, where the pregnancy resulted from rape or incest, or where the fetus had a severe anomaly. The Catholic Church opposed the new measure, and the Senat (Poland's upper house), on October 3, had voted 40 to 52 (with 2 abstentions) against the amendment. Although the Sejm had previously voted 208 to 61 (with 15 abstentions) in favor of the amendment, 120 of those opposed to the measure, primarily members of the Polish Peasants Party (part of Poland's ruling coalition), had walked out in protest just before an August tally. The Democratic Left Alliance, the other coalition partner, supports the amendment. The most recent vote in the Sejm overturns the Senat veto; however, before the law can go into effect in 1997, it must be signed by President Aleksandr Kwasniewski (a supporter) after a review by Poland's conservative constitutional tribunal.

  1. DISPERSION OF NANODIAMOND AND ULTRA-FINE POLISHING OF QUARTZ WAFER

    Institute of Scientific and Technical Information of China (English)

    Yongwei Zhu; Zhijing Feng; Baichun Wang; Xianyang Xu

    2004-01-01

    Mechanochemical Modification (MCM) of nanodiamond surface with DN-10 was studied in relation to the performance of nanodiamond in polishing quartz wafers. Results show that the modified nanodiamond is more stable in the pH range 8~11. A super smooth surface with an average roughness of 0.214 nm was achieved using a nanodiamond-based slurry regulated by N-(2-hydroxyethyl)ethylenediamine. It is suggested that the principal ultra-fine polishing mechanism of quartz wafer involves atom-level removal under the synergism of chemical and mechanical actions.

  2. Combined effects of crystallography, heat treatment and surface polishing on blistering in tungsten exposed to high-flux deuterium plasma

    Science.gov (United States)

    Zayachuk, Y.; Tanyeli, I.; Van Boxel, S.; Bystrov, K.; Morgan, T. W.; Roberts, S. G.

    2016-08-01

    For tungsten exposed to low-energy hydrogen-plasmas, it has been thought that grains with surface normal are most susceptible to blistering while those with surface normal are virtually impervious to it. Here, we report results showing that non-uniformity of blister distribution depends on the state of the surface due to polishing. In electrochemically polished material blisters appear on the grains with all orientations, while in mechanically polished material blister-free areas associated with particular orientations emerge. On the other hand, blistering is shown to have a strong dependence on the level of deformation within particular grains in partially recrystallized material.

  3. Compound antimalarial ethosomal cataplasm: preparation, evaluation, and mechanism of penetration enhancement

    Directory of Open Access Journals (Sweden)

    Shen S

    2015-06-01

    Full Text Available Shuo Shen, Shu-Zhi Liu, Yu-Shi Zhang, Mao-Bo Du, Ai-Hua Liang, Li-Hua Song, Zu-Guang Ye Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, People’s Republic of China Abstract: Malaria is still a serious public health problem in some parts of the world. The problems of recurrence and drug resistance are increasingly more serious. Thus, it is necessary to develop a novel antimalarial agent. The objectives of this study were to construct a novel compound antimalarial transdermal nanosystem–ethosomal cataplasm, to investigate its characteristics and efficiency, and to systematically explore the penetration-enhancing mechanisms of ethosomal cataplasm. Artesunate-loaded ethosomes and febrifugine-loaded ethosomes were prepared, and their characteristics were evaluated. Drug-loaded ethosomes were incorporated in the matrix of cataplasm to form the compound antimalarial ethosomal cataplasm. With the help of ethosomal technology, the accumulated permeation quantity of artesunate significantly increased at 8 hours after administration, which was 1.57 times as much as that of conventional cataplasm. Soon after administration, the ethosomal cataplasm could make a large quantity of antimalarial drug quickly penetrate through skin, then the remaining drug in the ethosomal cataplasm could be steadily released. These characteristics of ethosomal cataplasm are favorable for antimalarial drugs to kill Plasmodium spp. quickly and prevent the resurgence of Plasmodium spp. As expected, the ethosomal cataplasm showed good antimalarial efficiency in this experiment. The negative conversion rates were 100% and the recurrence rates were 0% at all dosages. The mechanism of penetration enhancement of the ethosomal cataplasm was systematically explored using an optics microscope, polarization microscope, and transmission electron microscopy. The microstructure, ultrastructure, and birefringent structure in skin were observed. Data

  4. Professional Training of Economists at Polish Universities

    Directory of Open Access Journals (Sweden)

    Ogienko Olena

    2016-09-01

    Full Text Available Polish experience in professional training of economists at university has been generalized. Structural, content and procedural peculiarities of the training have been defined. It has been proved that key factors for reforming economic education in Poland are globalization, internationalization, integration, technologization and informatization. It has been found out that forming of economic competency is based on the competency-based and personality-based approaches that allow to direct the educational process at a student as an active subject of learning, to create conditions for his/her creative potential development, to educate a competent specialist possessing all the competencies needed in professional activity. The influence of Polish universities’ integration into European system of student exchange on the quality of future specialists’ training has been revealed. Flexibility and variety of syllabi and curricula of economists’ professional training at Polish universities have been emphasized. Among perspective teaching methods we have singled out situational modeling as it allows to create situations at most approximated to those in professional activity, is oriented at co-creation and teamwork. It has been found out that the peculiarities of economists’ professional training at Polish universities are flexibility, diversification, standardization, personalization and adaptation to modern labour market. It has been proved that the result of economists’ professional training at Polish universities is a highly qualified specialist able to adapt to dramatic changes in economy and society.

  5. Variation in the Ace Gene in Elite Polish Football Players

    Directory of Open Access Journals (Sweden)

    Cięszczyk Paweł

    2016-12-01

    Full Text Available Purpose. A common polymorphism in the angiotensin converting enzyme I gene (the ACE I/D variant represents one of the first characterized and the most widely studied genetic variants in the context of elite athletes status and performance related traits. The aim of the study was to determine the genotype and allele distribution of the allele and genotype of the ACE gene in Polish male football players. Methods. The total of 106 Polish male professional football players were recruited. They were divided into groups according to the position in the field: forwards, defenders, midfielders, and goalkeepers. For controls, samples were prepared with 115 unrelated volunteers. DNA was extracted from the buccal cells donated by the subjects, and the PCR amplification of the polymorphic region of the ACE gene containing either the insertion (I or deletion (D fragment was performed. Results. The genotype distribution and allele frequencies among all football players did not differ significantly when compared with sedentary control individuals (p = 0.887, p = 0.999, respectively. Likewise, the analysis of forwards, defenders, midfielders, and goalkeepers revealed no significant differences in either ACE genotype or allele frequencies. Conclusions. We did not provide evidence for difference of variation of the ACE I/D polymorphism between Polish football players and controls, as we did not obtain any statistically significantly higher frequency of either of the analysed alleles (I and D or genotypes (DD, ID, and II in the studied subgroups. It may be suspected that harbouring of I/D allelic variants of the ACE gene neither decreases nor increases the probability of being a professional football player in Poland.

  6. Preliminary study of disc hydrodynamic polishing.

    Science.gov (United States)

    Li, Yan; Lin, Bin; Zhang, XiaoFeng; Liu, PengFei

    2016-10-01

    In this paper, a developed polishing method based on elastic emission machining and Jules Verne-a variation on fluid jet polishing-is presented. This method is named disc hydrodynamic polishing (DHDP). A computational fluid dynamics (CFD)-based model that consists of a CFD model and an erosion model is introduced to predict the surface roughness obtained by DHDP. The performance of DHDP is studied by experiments. The slurry used in the experiments comprises 95% deionized water and 5% cerium oxide particles. Fused-silica glass is chosen as the workpiece. After the experiments, an ultrasmooth surface without cracks is obtained. The simulation results principally coincide with the experimental results. The experimental results show that the actual roughness is slightly less than the prediction and smaller particles are more favorable for obtaining a better surface roughness.

  7. Removal Of Optical Coatings Without Polishing

    Science.gov (United States)

    Gourley, Helen

    1980-11-01

    A process for removing antireflection, mirror and polarizer coatings has been developed at ILC, based on work begun by LLL (Applied Optics Vol. 17, No. 12, 15 June 1978 - "Notes on Optical Coating Removal", N.J. Brown). Because of the danger (personnel hazard) involved in the hydrofluoric acid process, we employed an ammonium bifluoride solution, combined with various polishing components. The substrates, generally BK7, are fairly soft and also sensitive to chemical action. Therefore we have limited our polishing materials to aluminum oxide powder graded at 0.1 pm or smaller. For some coatings, no polishing material is used, as the ammonium bifluoride solution is adequate to remove the coating. The resulting clean surface is washed and neutralized, and is then ready for recoating.

  8. Priorities in the Polish health care system.

    Science.gov (United States)

    Nieszporska, Sylwia

    2017-01-01

    Since 1999, Polish health policy has changed, the quality of services has increased, and also the level of financing, mainly from public benefits. Despite constant growth of indexes reflecting the health status of Polish society, such as life expectancy, quality of life, or decreasing index of deaths at birth, just as in the majority of European countries, in Poland the society is growing older, which implies the necessity to reorganize the system. In this paper, the author has described the most important factors that determine the operation of the health system in Poland, as well as presents the ways it was restructured over the last few years, taking into consideration the structural, legislative, financial, organizational, and quantitative aspects. Also, the latest trends in Polish health policy, which take into account new goals of the system, have been presented within.

  9. Developing free morphological data for Polish

    Directory of Open Access Journals (Sweden)

    Adam Radziszewski

    2015-11-01

    Full Text Available Developing free morphological data for Polish A limiting factor in construction of Natural Language Processing (NLP systems is often the availability of morphological resources. This indeed happens for Polish: the freely available corpus with manual morpho-syntactic annotation (part of the IPI PAN Corpus is not coupled with any free morphological analyser. There exists a very large morphological dictionary of Polish available under a free licence – Morfologik. Unfortunately, its tagset differs significantly from the tagset of the corpus and, what is more, its morphological description lacks desired rigour. We amend this situation by performing a massive conversion of the dictionary into the tagset compliant with the corpus. The conversion results in a free dictionary containing entries for almost 3.5 million different word forms. In this article we report on our methodology, discuss some morphological and syntactic issues related to both tagsets and present the characteristics of the resulting dictionary.

  10. Stress 'deafness' in a language with fixed word stress: an ERP study on Polish

    Directory of Open Access Journals (Sweden)

    Ulrike eDomahs

    2012-11-01

    Full Text Available The aim of the present contribution was to examine the factors influencing the prosodic processing in a language with predictable word stress. For Polish, a language with fixed penultimate stress but several well-defined exceptions, difficulties in the processing and representation of prosodic information have been reported (e.g., Peperkamp & Dupoux, 2002. The present study utilized event-related potentials (ERPs to investigate the factors influencing prosodic processing in Polish. These factors are i the predictability of stress and ii the prosodic structure in terms of metrical feet. Polish native speakers were presented with correctly and incorrectly stressed Polish words and instructed to judge the correctness of the perceived stress patterns. For each stress violation an early negativity was found which was interpreted as reflection of an error-detection mechanism, and in addition exceptional stress patterns (= antepenultimate stress and post-lexical (= initial stress evoked a task-related positivity effect (P300 whose amplitude and latency is correlated with the degree of anomaly and deviation from an expectation. Violations involving the default (= penultimate stress in contrast did not produce such an effect. This asymmetrical result is interpreted to reflect that Polish native speakers are less sensitive to the default pattern than to the exceptional or post-lexical patterns. Behavioral results are orthogonal to the electrophysiological results showing that Polish speakers had difficulties to reject any kind of stress violation. Thus, on a meta-linguistic level Polish speakers appeared to be stress-‘deaf’ for any kind of stress manipulation, whereas the neural reactions differentiate between the default and lexicalized patterns.

  11. Stress "deafness" in a Language with Fixed Word Stress: An ERP Study on Polish.

    Science.gov (United States)

    Domahs, Ulrike; Knaus, Johannes; Orzechowska, Paula; Wiese, Richard

    2012-01-01

    The aim of the present contribution was to examine the factors influencing the prosodic processing in a language with predictable word stress. For Polish, a language with fixed penultimate stress but several well-defined exceptions, difficulties in the processing and representation of prosodic information have been reported (e.g., Peperkamp and Dupoux, 2002). The present study utilized event-related potentials (ERPs) to investigate the factors influencing prosodic processing in Polish. These factors are (i) the predictability of stress and (ii) the prosodic structure in terms of metrical feet. Polish native speakers were presented with correctly and incorrectly stressed Polish words and instructed to judge the correctness of the perceived stress patterns. For some stress violations, an early negativity was found which was interpreted as a reflection of an error-detection mechanism. In addition, exceptional stress patterns (=antepenultimate stress) and post-lexical (=initial) stress evoked a task-related positivity effect (P300) whose amplitude and latency is correlated with the degree of anomaly and deviation from an expectation. In contrast, violations involving the default (=penultimate stress) did not produce such an effect. This asymmetrical result is interpreted to reflect that Polish native speakers are less sensitive to the default pattern than to the exceptional or post-lexical patterns. Behavioral results are orthogonal to the electrophysiological results showing that Polish speakers had difficulties to reject any kind of stress violation. Thus, on a meta-linguistic level Polish speakers appeared to be stress-"deaf" for any kind of stress manipulation, whereas the neural reactions differentiate between the default and lexicalized patterns.

  12. An experimental study on the ultra-precision polishing of quartz crystal using MR fluids and micro abrasives

    Science.gov (United States)

    Kim, D. W.; Lee, J. W.; Cho, M. W.; Choi, S. B.

    2009-02-01

    This paper presents ultra-precision MR polishing results of quartz crystal, which has been widely used in many applications, such as piezo-electric transducer, surface acoustic wave (SAW) filters and SAW resonators, etc. It is known that smooth surface with sub-nanometer roughness is needed for higher-frequency application. The MR fluids, used for the polishing, consist of DI water based carbonyl iron (CI), nonmagnetic polishing micro abrasives, and required amount of stabilizers. In the process, mixed fluids were supplied into the gap between a rotating wheel (with electromagnetic field) and the workpiece. Then, the micro abrasives contained in the fluids perform material removal action from the workpiece. Such material removal mechanism in the MR polishing is considered as a process governed by the Bingham flow in the contact zone. In this study, material removal characteristics and generated surface roughness of the quartz crystal specimens using the MR polishing process were investigated through a series of experiments. The surface roughness variations of the polished specimens were investigated by changing imposed polishing conditions, such as wheel speed, magnetic field intensity. As a result, very fine surface roughness of Ra=0.770nm was obtained.

  13. Mechanical and Thermal Properties of Poly(urethane urea) Nanocomposites Prepared with Diamine-Modified Laponite

    OpenAIRE

    2008-01-01

    Nanocomposites based on segmented poly(urethane urea) were prepared by reacting a poly(diisocyanate) with diamine-modified Laponite-RD nanoparticles that served as a chain extender. The nanocomposites were prepared at a constant NH2 to NCO mole ratio of 0.95, while varying the fraction of diamine-modified Laponite relative to the free diamine chain extender. Compared to neat poly(urethane urea), all nanocomposites showed increased tensile strength and elongation at break. As Laponite loading ...

  14. Preparation of three-layered porous PLA/PEG scaffold: relationship between morphology, mechanical behavior and cell permeability.

    Science.gov (United States)

    Scaffaro, R; Lopresti, F; Botta, L; Rigogliuso, S; Ghersi, G

    2016-02-01

    Interface tissue engineering (ITE) is used to repair or regenerate interface living tissue such as for instance bone and cartilage. This kind of tissues present natural different properties from a biological and mechanical point of view. With the aim to imitating the natural gradient occurring in the bone-cartilage tissue, several technologies and methods have been proposed over recent years in order to develop polymeric functionally graded scaffolds (FGS). In this study three-layered scaffolds with a pore size gradient were developed by melt mixing polylactic acid (PLA) and two water-soluble porogen agents: sodium chloride (NaCl) and polyethylene glycol (PEG). Pore dimensions were controlled by NaCl granulometry while PEG solvation created a micropores network within the devices. Scaffolds were characterized from a morphological and mechanical point of view in order to find a correlation between the preparation method, the pore architecture and compressive mechanical behavior. Biological tests were also performed in order to study the effect of pore size gradient on the permeation of different cell lines in co-culture. To imitate the physiological work condition, compressive tests were also performed in phosphate buffered saline (PBS) solution at 37°C. The presented preparation method permitted to prepare three-layered scaffolds with high control of porosity and pore size distribution. Furthermore mechanical behaviors were found to be strongly affected by pore architecture of tested devices as well as the permeation of osteoblast and fibroblast in-vitro.

  15. POLISH-RUSSIAN COOPERATION OF POMORSKIE PROVINCE

    Directory of Open Access Journals (Sweden)

    Christina GOMULKA

    2015-01-01

    Full Text Available Polish-Russian Cooperation of Pomorskie Province commenced in 1999 and was based on the intergovernmental agreements. The new agreement, executed between the authorities of the Pomeranian Province and Kaliningrad Oblast in 2002, provided for cooperation in many areas. The contacts between the partners were dominated by economic cooperation. The Polish–Russian cooperation stopped with Polish accession to the Schengen zone. Cooperation resumed when in 2011 and agreement on small cross-border traffic was signed and then ratified in 2012. 

  16. An investigation on the compressibility of aluminum/nano-alumina composite powder prepared by blending and mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Razavi Hesabi, Z. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran 14588 (Iran, Islamic Republic of); Hafizpour, H.R. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran 14588 (Iran, Islamic Republic of); Simchi, A. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran 14588 (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran 14588 (Iran, Islamic Republic of)], E-mail: simchi@sharif.edu

    2007-04-25

    The densification response of aluminum powder reinforced with 5 vol.% nanometric alumina particles (35 nm) during uniaxial compaction in a rigid die was studied. The composite powder was prepared by blending and mechanical milling procedures. To determine the effect of the reinforcement nanoparticles on the compressibility of aluminum powder, monolithic Al powder, i.e. without the addition of alumina, was also examined. It was shown that at the early stage of compaction when the rearrangement of particles is the dominant mechanism of the densification, disintegration of the nanoparticle clusters and agglomerates under the applied load contributes in the densification of the composite powder prepared by blending method. As the compaction pressure increases, however, the load partitioning effect of the nanoparticles decreases the densification rate of the powder mixture, resulting in a lower density compared to the monolithic aluminum. It was also shown that mechanical milling significantly impacts the compressibility of the unreinforced and reinforced aluminum powders. Morphological changes of the particles upon milling increase the contribution of particle rearrangement in densification whilst the plastic deformation mechanism is significantly retarded due to the work-hardening effect of the milling process. Meanwhile, the distribution of alumina nanoparticles is improved by mechanical milling, which in fact, affects the compressibility of the composite powder. This paper addresses the effect of mechanical milling and reinforcement nanoparticles on the compressibility of aluminum powder.

  17. Microstructure and Mechanical Properties of Thin-Multilayer Ti/Al Laminates Prepared by One-Step Explosive Bonding

    Science.gov (United States)

    Fan, Minyu; Yu, Weiwei; Wang, Wentao; Guo, XunZhong; Jin, Kai; Miao, Runjie; Hou, Wenqing; Kim, Naksoo; Tao, Jie

    2017-01-01

    Thin-multilayer Ti/Al laminates were prepared by one-step explosive bonding method to investigate the interface bonding and mechanical properties owing to their potential application in aerospace and auto industry. It was found that Ti/Al laminates prepared at the detonation velocity of 2100 m/s exhibited superior surface quality without any defects in comparison with other detonation velocities owing to the optimum explosive pressure and impact velocity. The interface morphologies and element distribution of Ti/Al laminates prepared at the detonation velocity of 2100 m/s were characterized by means of SEM and EDS. The results indicated that the linear and wavy bonding interface coexisted and element diffusion occurred in the interfacial zone. Furthermore, thin-multilayer Ti/Al laminates possessed high microhardness, excellent interlaminar shear and tensile properties.

  18. Preparation of nanoporous systems for the study of the mechanical properties of silica aerogels by Molecular Dynamics simulations

    Science.gov (United States)

    Rivas Murillo, John S.; Bachlechner, Martina E.; Barbero, Ever J.

    2009-03-01

    This presentation focuses on the application of the Molecular Dynamics technique to study the mechanical properties of silica aerogels through the simulation of a tension test. It covers multiple areas, including aspects related to the preparation of a well-relaxed nanoporous system from the expansion of an amorphous bulk sample and the influence of the initial configuration of the system on the final results of the simulated tension test. The results presented here will help to develop a more complete procedure to prepare a proper sample for the study of the mechanical properties of a nanoporous system by using Molecular Dynamics. Comparison of the simulation results and previously published experimental data is provided

  19. Investigation of the coercivity mechanism for Nd-Fe-B based magnets prepared by a new technique of strip casting

    Institute of Scientific and Technical Information of China (English)

    LI Bo; HU Jifan; WANG Dongling; GUO Binglin; WANG Xinlin

    2004-01-01

    The coercivity mechanism of Nd-Fe-B based magnets prepared by a new technique of strip casting was investigated. Different from the traditional magnets, α-Fe phases are difficult to be found in Nd-Fe-B magnets prepared by strip casting. Meanwhile, the rich-Nd phases occur not only near the grain boundaries of main phases, but also within the main-phase grains. Investigation on the magnetizing field dependence of the coercivity for the (Nd0.935Dy0.065)14.5Fe79.4B6.1magnet and the temperature dependence of the coercivity for the Nd14.5Fe79.4B6.1magnet have been done. Results show that coercivities for strip casting magnets are controlled by the nucleation mechanism.

  20. [Features of adhesion of anaerobic periodontopathogenic bacteria and Candida albicans fungi to experimental samples of basis dental plastic depending on surface roughness and polishing method].

    Science.gov (United States)

    Tsarev, V N; Ippolitov, E V; Trefilov, A G; Arutiunov, S D; Pivovarov, A A

    2014-01-01

    Study the main surface parameters of milled polyacrylic materials using atomic force microscopy and primary microbial adhesion of periodontopathogenic group bacteria and Candida albicans fungi taking into consideration the method of sample polishing. Studied samples: mill-treated without polishing (control); ergobox polished; polished in dental laboratory conditions; polished by a rubber brush in dentists' office. Microbial strains belonging to periodontopathogenic species (clinical isolates) that had been isolated from periodontal pockets of periodontitis patients: Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus sanguis, C. albicans fungi were used for modelling experiments of primary adhesion of microbes to the material samples. S. sanguis had the highest degree of adhesion to polymer after milling, P. gingivalis, C. albicans--medium, F. nucleatum--low. A significant reduction of adhesion is observed during polishing in dental laboratory conditions or ergobox, less significant--during polishing in dental office. The data obtained allow to make a conclusion that the samples from polymer materials for preparation of prosthesis basis have varying degree of intensity of microbial adhesion of members of periodontopathogenic microflora and C. albicans fungi that depends on the polishing method, that accordingly determined the differences in colonization resistance against formation of microbial biofilm during polymer use in clinical conditions. . ,

  1. Preparation, formation mechanism and photoelectric properties of well-aligned CuSbS{sub 2} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Liang, E-mail: sliang@ustc.edu.cn; Li, Yanan; Wu, Chunyan; Dai, Yumei

    2015-11-05

    Well-aligned CuSbS{sub 2} single crystalline nanowires array has been prepared via a solvothermal synthetic route. The as-prepared CuSbS{sub 2} nanowires are uniform with a growth direction perpendicular to the (101) planes. Porous anodic aluminum oxide was used as a morphology directing template and was found to play a significant role for the formation of single crystalline CuSbS{sub 2} nanowires. Thin film prepared from CuSbS{sub 2} nanowires displayed an obvious photoelectric response, suggesting its potential application as a low cost solar absorber material. A possible formation mechanism for the single crystalline CuSbS{sub 2} nanowires array is proposed. The structure, morphology, composition and optical absorption properties of the as-prepared CuSbS{sub 2} nanowires were characterized using X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectrometry and UV–Vis spectrophotometry. - Highlights: • Uniform CuSbS{sub 2} single crystalline nanowires array has been synthesized. • The bandgap of the as-prepared CuSbS{sub 2} nanowires is 1.45 eV. • CuSbS{sub 2} nanowires displayed an obvious photoelectric response. • The growth direction of CuSbS{sub 2} nanowires is perpendicular to (101) planes.

  2. Mechanical properties of 9Cr–1W reduced activation ferritic martensitic steel weldment prepared by electron beam welding process

    Energy Technology Data Exchange (ETDEWEB)

    Das, C.R., E-mail: chitta@igcar.gov.in [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Albert, S.K. [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Sam, Shiju [Institute for Plasma Research, Gandhinagar (India); Mastanaiah, P. [Defense Research and Development Laboratory, Hyderabad (India); Chaitanya, G.M.S.K.; Bhaduri, A.K.; Jayakumar, T. [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Murthy, C.V.S. [Defense Research and Development Laboratory, Hyderabad (India); Kumar, E. Rajendra [Institute for Plasma Research, Gandhinagar (India)

    2014-11-15

    Highlights: • Width of HAZ is smaller in the 9Cr–1W RAFM weldment prepared by EB process compared to that reported for TIG weldments in literature. • Weld joint is stronger than that of the base metal. • Toughness of weld metal prepared by EB welding process is comparable to that (in PWHT condition) prepared by TIG process. • DBTT of as-welded 9Cr–1W RAFM weldment prepared by EB process is comparable to that reported for TIG weld metal in PWHT condition. - Abstract: Microstructure and mechanical properties of the weldments prepared from 9Cr–1W reduced activation ferritic martensitic (RAFM) steel using electron beam welding (EBW) process were studied. Microstructure consists of tempered lath martensite where precipitates decorating the boundaries in post weld heat treated (PWHT) condition. Lath and precipitate sizes were found to be finer in the weld metal than in base metal. Accordingly, hardness of the weld metal was found to be higher than the base metal. Tensile strength of the cross weldment specimen was 684 MPa, which was comparable with the base metal tensile strength of 670 MPa. On the other hand, DBTT of 9Cr–1W weld metal in as-welded condition is similar to that reported for TIG weld metal in PWHT condition.

  3. An Experimental Analysis of Price Formation on the Polish Power Exchange

    Directory of Open Access Journals (Sweden)

    Drabik Ewa

    2015-12-01

    Full Text Available The Polish energy market gained its competitive character in late 1990s. At that time in majority of European countries a new law was enacted (in Poland – in 1987, which enabled the creation of internal energy markets. The Polish Power Exchange has been functioning since the end of 1999. However, from the very onset it has constituted a vital component of under grounding liberalization of electricity market. Since it was created the Polish Power Exchange has served as a market mechanism for setting objective energy market price. Support and control of the Polish Financial Supervision Authority guarantee the security of concluded transactions. The spot energy market was created as the first one and has functioned according to the rule of the double auction. The model of Sadrieh will be used for the description of the auction rules applied to the spot energy trade on the Polish Power Exchange. Furthermore, an algorithm on the basis of which it is possible to forecast transaction prices is presented. The effectiveness of this algorithm will be compared with other traditional methods of forecasting transaction prices.

  4. Contemporary Contrastive Studies of Polish, Bulgarian and Russian Neologisms versus Language Corpora

    Directory of Open Access Journals (Sweden)

    Joanna Satoła-Staśkowiak

    2015-06-01

    Full Text Available Contemporary Contrastive Studies of Polish, Bulgarian and Russian Neologisms versus Language Corpora In the field of Slavonic linguistics contrastive studies of neologisms occupy little place, the newest words are insufficiently described and classified. The aim of this article is to draw attention to the need for contrastive description of the newest lexis and checking exclusively one of many possibilities of obtaining Polish, Bulgarian and Russian neologisms. Language corpora, as this possibility is in question, are not the only source from which the author obtains her research material, yet a growing interest in corpora has inspired her to also use this method. The author wants to show the reader to what degree language corpora can help in building the thesaurus of Polish, Bulgarian and Russian neologisms. Making an attempt to confront a collection of neologisms of contemporary Polish, Bulgarian and Russian language, the author points out the need to standardize the description (identical for each of the analysed languages, which she intends to propose in another publications on neologisms in Polish, Bulgarian and Russian language. The application of contrastive method to three different but related languages from the Slavonic group will help, in her opinion, to discover more mechanisms of new words coming into existence and examine the newest derivative processes and their productivity.

  5. Orthogonal experiment and analysis of power spectral density on process parameters of pitch tool polishing

    Science.gov (United States)

    Meng, Kai; Wan, Yongjian; Wu, Fan; Shen, Lijun; Wu, Hsing-Yu

    2017-02-01

    Mid to high spatial frequency error (MSFR and HSFR) should be strictly controlled in modern optical systems. Pitch tool polishing (PTP) is an effective ultra-smoothing surface manufacturing method to control MSFR and HSFR. But it is difficult to control because it is affected by a lot of factors. The present paper describes the pitch tool polishing study based on eighteen well-planned orthogonal experiments (OA18 matrix). Five main process factors (abrasive particle size, slurry concentration, pad rotation speed, acidity and polishing time) in pitch tool polishing process were investigated. In this study, power spectral density (PSD) based on Fourier analysis of surface topography data obtained by white light interferometer was used as the results of orthogonal experiments instead of material removal rate and surface roughness. A normalization method of PSD was proposed as the range analysis rule. Three parts of spatial frequency bandwidth were selected and discussed. Acidity is the most important factor in part 1 and slurry concentration is the most significant one in part 2; while acidity is the least influenced one in part 3. The result in each part was explained by two-step material removal mechanism. At last, suggestions in low and high spatial frequency are given for pitch tool polishing.

  6. Preparing Fe5C2 Intermetallic Compound by Mechanical Alloying Method at Room Temperature and Normal Pressure

    Institute of Scientific and Technical Information of China (English)

    何正明; 钟敏建; 沈伟星; 张正明

    2003-01-01

    Single phase Fe5C2 intermetallic compound was prepared by mechanical alloying method. The phase and crystal structure of sample were analyzed with X-ray differaction spectrum. The decomposing temperature of the Fe5C2 compound is 596.4℃ determined by the DSC curve. It is further shown that the size of nanometer crystal grain is an important condition for carrying out the solid state reaction at room temperature and normal pressure.

  7. Study of the Contact Force in Free-form Surfaces Compliant EDM Polishing by Robot

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With an elastic negative pole being driven by ultra so nic vibration and being moved along the surface of work-piece compliantly by ro bot, a new kind of effective EDM, the compliant EDM, cuts the electrically condu ctive materials away and polishes work-piece of free-form surface. The study o f the contact force between the end of polishing tool and the surface of work-p iece is the key for the compliant EDM to study its cutting mechanism and to make better use of it. This paper makes a model for the cont...

  8. Surface roughness and staining susceptibility of composite resins after finishing and polishing.

    Science.gov (United States)

    Berger, Sandrine Bittencourt; Palialol, Alan Rodrigo Muniz; Cavalli, Vanessa; Giannini, Marcelo

    2011-02-01

    The study aims to investigate the influence of filler size and finishing systems on the surface roughness and staining of three composite resins. Three composites, classified according to their filler size, were selected: Filtek Supreme Plus/nanofill (3M ESPE, St. Paul, MN, USA), Esthet-X/minifill (Dentsply Caulk, Milford, DE, USA), and Renamel Microfill/microfill (Cosmedent Inc., Chicago, IL, USA). Composite specimens were made in stainless steel split molds and polished with Sof-Lex (3M ESPE), Enhance+PoGo (Dentsply Caulk), or FlexiDiscs+Enamelize (Cosmedent Inc.). Finishing systems were used according to the manufacturers' instructions and polished surfaces were evaluated with a profilometer and then immersed in 2% methylene blue for 24 hours. Specimens were then prepared for spectrophotometric analysis and results were statistically analyzed by two-way analysis of variance and Tukey's test. No significant differences in surface roughness among the composites were found when the surfaces were treated with Enhance+PoGo. In addition, no differences were observed when the Filtek Supreme Plus composite was submitted to surface staining evaluation. In general, the composites polished with the finishing systems from the same company demonstrated lower surface roughness and staining. The results of this study recommend that composite resins could be finished and polished with finishing systems supplied by the composite's manufacturer. The surface roughness and staining of composite resins were not influenced solely by filler size. Dentists should finish and polish composite resin with the polishing agent supplied by the same manufacturer. The smallest filler size does not necessarily result in a low surface roughness and staining susceptibility. © 2011, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2011, WILEY PERIODICALS, INC.

  9. 21 CFR 872.6030 - Oral cavity abrasive polishing agent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oral cavity abrasive polishing agent. 872.6030... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6030 Oral cavity abrasive polishing agent. (a) Identification. An oral cavity abrasive polishing agent is a device in paste or powder...

  10. Surface Roughness, Microhardness, and Microleakage of a Silorane-Based Composite Resin after Immediate or Delayed Finishing/Polishing.

    Science.gov (United States)

    Lins, Fernanda Carvalho Rezende; Ferreira, Raquel Conceição; Silveira, Rodrigo Richard; Pereira, Carolina Nemésio Barros; Moreira, Allyson Nogueira; Magalhães, Claudia Silami

    2016-01-01

    Objective. This study evaluated the effect of immediate or delayed finishing/polishing using different systems on the surface roughness, hardness, and microleakage of a silorane-based composite. Material and Methods. Specimens were made with silorane-based composite (Filtek P90, 3M ESPE) and assigned to the treatments: control (light-cured); aluminum oxide discs (Sof-Lex, 3M ESPE); diamond-impregnated silicone tips (Astropol, Ivoclar Vivadent); aluminum oxide-impregnated silicone tips (Enhance, Dentsply). Half of the specimens were finished/polished immediately and the rest after 7 days. Surface roughness (Ra, μm; n = 20) and Vickers microhardness (50 g; 45 s; n = 10) were measured. Cavities were prepared in bovine incisors and filled with Filtek P90. The fillings received immediate or delayed finishing/polishing (n = 10) and were subjected to dye penetration test (0.5% basic fuchsin, 24 h). Data were analyzed by ANOVA and Scheffe, Kruskal-Wallis, and Mann-Whitney tests (p polishing system significantly influenced roughness and microhardness (p polishing system (p = 0.309). For dentin, Sof-Lex discs and Astropol points promoted greater microleakage than Enhance points (p = 0.033). Conclusion. Considering roughness, microhardness, and microleakage together, immediate finishing/polishing of a silorane-based composite using aluminum oxide discs may be recommended.

  11. Surface Roughness, Microhardness, and Microleakage of a Silorane-Based Composite Resin after Immediate or Delayed Finishing/Polishing

    Directory of Open Access Journals (Sweden)

    Fernanda Carvalho Rezende Lins

    2016-01-01

    Full Text Available Objective. This study evaluated the effect of immediate or delayed finishing/polishing using different systems on the surface roughness, hardness, and microleakage of a silorane-based composite. Material and Methods. Specimens were made with silorane-based composite (Filtek P90, 3M ESPE and assigned to the treatments: control (light-cured; aluminum oxide discs (Sof-Lex, 3M ESPE; diamond-impregnated silicone tips (Astropol, Ivoclar Vivadent; aluminum oxide-impregnated silicone tips (Enhance, Dentsply. Half of the specimens were finished/polished immediately and the rest after 7 days. Surface roughness (Ra, μm; n=20 and Vickers microhardness (50 g; 45 s; n=10 were measured. Cavities were prepared in bovine incisors and filled with Filtek P90. The fillings received immediate or delayed finishing/polishing (n=10 and were subjected to dye penetration test (0.5% basic fuchsin, 24 h. Data were analyzed by ANOVA and Scheffe, Kruskal-Wallis, and Mann-Whitney tests (p<0.05. Results. The finishing/polishing system significantly influenced roughness and microhardness (p<0.0001. For enamel, microleakage was not affected by the finishing/polishing system (p=0.309. For dentin, Sof-Lex discs and Astropol points promoted greater microleakage than Enhance points (p=0.033. Conclusion. Considering roughness, microhardness, and microleakage together, immediate finishing/polishing of a silorane-based composite using aluminum oxide discs may be recommended.

  12. Wastewater polishing by a channelized macrophyte-dominated wetland and anaerobic digestion of the harvested phytomass

    Science.gov (United States)

    : Constructed wetlands (CW) offer a mechanism to meet regulatory standards for wastewater treatment while minimizing energy inputs. To optimize CW wastewater polishing activities and investigate integration of CW with energy production from anaerobic digestion we constructed a pair of three-tier ch...

  13. Magnetic force improvement and parameter optimization for magnetic abrasive polishing of AZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The magnetic force acting on workpieee to be machined plays a significantly important role in magnetic abrasive polishing process.But in a case of polishing nonferrous materials,the strength of magnetic force is very low and it leads lower polishing efficiency.The magnesium alloy that has superior mechanical properties for industrial application such as a lightweight and high specific strength is one of the most famous nonferrous materials.An improving strategy of the magnetic force for me AZ31 magnesium alloy installed with a permanent magnet was proposed and experimental verification Was carded out.For the proposed strategy,the effect of process parameters on the surface roughness of the AZ31 magnesium alloy Was evaluated by a design of experimental method.

  14. Polishing Difficult-To-Reach Cavities

    Science.gov (United States)

    Malinzak, R. Michael; Booth, Gary N.

    1990-01-01

    Springy abrasive tool used to finish surfaces of narrow cavities made by electrical-discharge machining. Robot arm moves vibrator around perimeters of cavities, polishing walls of cavities as it does so. Tool needed because such cavities inaccessible or at least difficult to reach with most surface-finishing tools.

  15. Fluid jet polishing of optical surfaces

    NARCIS (Netherlands)

    Fähnle, O.W.; Brug, H. van; Frankena, H.J.

    1998-01-01

    We present a new finishing process that is capable of locally shaping and polishing optical surfaces of complex shapes. A fluid jet system is used to guide a premixed slurry at pressures less than 6 bars to the optical surface. We used a slurry comprising water and 10% #800 SiC abrasives (21.8 μm to

  16. Sexual Health of Polish Athletes with Disabilities

    Directory of Open Access Journals (Sweden)

    Ryszard Plinta

    2015-06-01

    Full Text Available The purpose of this study was to determine sexual functioning of Polish athletes with disabilities (including paralympians. The study encompassed 218 people with physical disabilities, aged between 18 and 45 (149 men and 69 women. The entire research population was divided into three groups: Polish paralympians (n = 45, athletes with disabilities (n = 126 and non-athletes with disabilities (n = 47. The quality of sexual life of Polish paralympians was measured by using the Polish version of Female Sexual Function Index and International Index of Erectile Function. Clinically significant erectile dysfunctions were most often diagnosed in non-athletes (83.33% with 50% result of severe erectile dysfunctions, followed by athletes and paralympians with comparable results of 56.98% and 54.17% respectively (p = 0.00388. Statistically significant clinical sexual dysfunctions concerned lubrication, orgasm as well as pain domains, and prevailed among female non-athletes (68.42%, 68.42% and 57.89%. Practising sports at the highest level has a favourable effect on the sexuality of men and women with physical disabilities. Men with physical disabilities manifest more sexual disorders than women, an aspect which should be considered by health-care professionals working with people with disabilities.

  17. Outgassing Properties of Chemically Polished Titanium Materials

    Science.gov (United States)

    Kurisu, Hiroki; Kimoto, Gou; Fujii, Hiroaki; Tanaka, Kazuhiko; Yamamoto, Setsuo; Matsuura, Mitsuru; Ishizawa, Katsunobu; Nomura, Takeru; Murashige, Nobuyuki

    We developed a chemical polishing (CP) for titanium materials applicable to ultrahigh vacuum (UHV) and extremely high vacuum (XHV) systems. The surface roughness, Ra, of the chemically polished titanium is obtained to be 25 nm by the atomic force microscopy measurement. This value is smaller than those of the base metal (BM) and the buff-polished (BP) samples. The thickness of the surface oxide layer of CP sample is estimated to be 7 nm by the cross section of transmission electron micrograph. Amount of desorption gas of CP sample obtained by the thermal desorption measurement is smaller than those of BM and BP sample, and is the same as that of the mechanochemically polished (MCP) sample. The outgassing rate of CP sample after baking at 150°C×20 h is obtained to be 7×10-13 Pa•m•s-1. This value is lower than that of standard vacuum materials by two orders of magnitude after the ordinary baking.

  18. Analysis of Polish Vowels of Tracheoesophageal Speakers.

    Science.gov (United States)

    Mięsikowska, Marzena

    2017-03-01

    The aim of this study was to determine the acoustical differences between normal and tracheoesophageal Polish speakers during Polish vowel production. Formant frequencies, namely, the first (F1) and second (F2) formant frequencies for 6 Polish vowels produced by 11 normal and 11 tracheoesophageal speakers, were analyzed using statistical analysis of variance and discriminant analysis. Spectral analysis showed that the F1 and F2 values of Polish vowels produced by tracheoesophageal speakers were significantly higher than those produced by normal speakers, with the exception of the F2 value of /i/ produced by tracheoesophageal speakers. Analysis of variance showed significant differences between speeches based on the F1 and F2 formant frequencies. Discriminant analysis based on the formant frequencies for F1 and F2 exhibited 73.33% of the mean classification score for tracheoesophageal speakers and 96.36% for normal speakers. Tracheoesophageal speakers exhibit higher F1 and F2 formant frequencies, with the exception of the F2 value for the vowel /i/ than normal speakers. Discriminant analysis showed that the classification process for TE speech exhibits lower accuracy due to the poorer classification of the vowels /i/, /u/, and /y/. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  19. Technological Advances of Robot Assisted Polishing

    DEFF Research Database (Denmark)

    Lazarev, Ruslan; Top, Søren; Grønbæk, Jens

    The efficient polishing of surfaces is very important in mould and die industry. Fine abrasive processes are widely used in industry for the first steps for the production of tools of high quality in terms of finishing accuracy, form and surface integrity. While manufacturing of most components r...

  20. Towards an event annotated corpus of Polish

    Directory of Open Access Journals (Sweden)

    Michał Marcińczuk

    2015-12-01

    Full Text Available Towards an event annotated corpus of Polish The paper presents a typology of events built on the basis of TimeML specification adapted to Polish language. Some changes were introduced to the definition of the event categories and a motivation for event categorization was formulated. The event annotation task is presented on two levels – ontology level (language independent and text mentions (language dependant. The various types of event mentions in Polish text are discussed. A procedure for annotation of event mentions in Polish texts is presented and evaluated. In the evaluation a randomly selected set of documents from the Corpus of Wrocław University of Technology (called KPWr was annotated by two linguists and the annotator agreement was calculated. The evaluation was done in two iterations. After the first evaluation we revised and improved the annotation procedure. The second evaluation showed a significant improvement of the agreement between annotators. The current work was focused on annotation and categorisation of event mentions in text. The future work will be focused on description of event with a set of attributes, arguments and relations.

  1. Polish Complementary Schools in Iceland and England

    Science.gov (United States)

    Zielinska, Malgorzata; Kowzan, Piotr; Ragnarsdóttir, Hanna

    2014-01-01

    Since 2004, the opening of labour markets has spurred a considerable number of Poles to emigrate e.g. to Iceland and England. Families with school age children have had the challenge of adapting to foreign environments and school systems. Polish complementary schools have played an important, albeit ambivalent, role in this process. Through focus…

  2. Neurocognitive Dimensions of Lexical Complexity in Polish

    Science.gov (United States)

    Szlachta, Zanna; Bozic, Mirjana; Jelowicka, Aleksandra; Marslen-Wilson, William D.

    2012-01-01

    Neuroimaging studies of English suggest that speech comprehension engages two interdependent systems: a bilateral fronto-temporal network responsible for general perceptual and cognitive processing, and a specialised left-lateralised network supporting specifically linguistic processing. Using fMRI we test this hypothesis in Polish, a Slavic…

  3. Knowledge Mobilisation in the Polish Education System

    Science.gov (United States)

    Fazlagic, Jan; Erkol, Arif

    2015-01-01

    Poland has made substantial progress in improving the quality of its education system in recent years. This paper aims to describe the situation of the Polish education system from a knowledge management perspective and, to some extent, through innovation policies in education. The many challenges, this paper argues, can be tackled only through…

  4. Professional Training of Economists at Polish Universities

    Science.gov (United States)

    Ogienko, Olena

    2016-01-01

    Polish experience in professional training of economists at university has been generalized. Structural, content and procedural peculiarities of the training have been defined. It has been proved that key factors for reforming economic education in Poland are globalization, internationalization, integration, technologization and informatization.…

  5. The effect of mechanical alloying on microstructure and mechanical properties of MoSi{sub 2} prepared by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Kermani, Milad, E-mail: miladkermani.mk@gmail.com; Razavi, Mansour; Rahimipour, Mohammad Reza; Zakeri, Mohammad

    2014-04-01

    Highlights: • Powders of Mo and Si according to MoSi{sub 2} stoichiometry were mechanically alloyed. • The as milled powder mixture was sintered using spark plasma sintering. • We investigated the microstructure and mechanical properties of samples. - Abstract: In this research the effect of mechanical alloying on the in situ synthesis–sintering behavior and mechanical properties of MoSi{sub 2} has been investigated. The Mo and Si powders according to MoSi{sub 2} stoichiometric composition were mechanically alloyed at different times. Then, the powders were subjected to spark plasma sintering process for preparing monolithic MoSi{sub 2}. X-ray diffraction pattern of the sintered samples showed that by increasing the mechanical alloying time, Mo{sub 5}Si{sub 3} has been formed. It seems that the formation of Mo{sub 5}Si{sub 3} is due to the effect of mechanical alloying on microstructure and thermodynamic condition of the reaction.

  6. Transformation of the Polish Banking Sector

    Directory of Open Access Journals (Sweden)

    Marek Stefański

    2009-07-01

    Full Text Available In the post-war period the banking system in Poland underwent two important system transitions: after 1946 and after 1989. The third transformation began after May 1, 2004, but it did not have a systemic character. The Polish banking sector started to operate on the Single European Market. The first part of the paper is devoted to the problems of the banks transformations after 1989 with a special focus on the quantitative development of banks in 19892008, and on subsequent privatisation and consolidation processes. The former intensified in 19891999, and the latter in 19992002. The consolidation process was very noticeable in the sector of cooperative banks after 1994. The second part of the paper includes an economic and financial analysis of the banks. A lot of attention was paid to the liquidity of the banking sector. It was assessed as good, which was confirmed by a short-term rating of Moodys and by the Financial Stability Report 2009, published by the National Bank of Poland in June 2009. The comparison of the net profit of the banking sector in 19972008 shows its dependence on the economic situation and policy. The number of banks with capital adequacy ratio well above the minimum required by the banking supervision is rising. The financial power ratings are not favorable for the domestic banks. The third part of the paper focuses on the development directions of the Polish banking sector. It may be concluded on the basis of the analysis that privatisation and consolidation processes will be continued. They will concentrate on the capital of foreign banks already operating in Poland. As compared with individual foreign banks, the potential of the Polish banking sector is week. The fourth part of the paper focuses on the presentation Polish banking sector in the context of European Union banking sector. The paper finishes with conclusions. Generally, Polish banks have to implement a strategy to enable them to compete on the Single

  7. Preparation and characterization of Na3BO3–Na2SO4 glass electrolytes with Na+ ion conductivity prepared by a mechanical milling technique

    Directory of Open Access Journals (Sweden)

    Kenji Suzuki

    2016-03-01

    Full Text Available The (100 − xNa3BO3·xNa2SO4 (0 ≤ x (mol% ≤ 50 glasses were prepared by mechanical milling. Halo patterns were observed in the compositions 0 ≤ x ≤ 50 by XRD measurements. The Raman spectra indicated that all the glasses were composed of BO33− anions, SO42− anions and Na+ cations. The (100 − xNa3BO3·xNa2SO4 glasses showed good deformation properties and a dense pellet was prepared by cold-press. The conductivities of the glasses increased with increasing Na2SO4 content, and the 50Na3BO3·50Na2SO4 glass showed the highest conductivity of 5.9 × 10−8 S cm−1 at 25 °C.

  8. The influence of tooth preparation and crown manipulation on the mechanical retention of stainless steel crowns.

    Science.gov (United States)

    Rector, J A; Mitchell, R J; Spedding, R H

    1985-01-01

    The belief that close adaptation of the metal margins to tooth surfaces in the undercut areas is the most important retentive feature, was borne out in this study. The type of preparation did not affect the retention of stainless steel crowns.

  9. Bismuth oxide based ceramics with improved electrical and mechanical properties: Part I. Preparation and characterisation

    NARCIS (Netherlands)

    Kruidhof, H.; Seshan, K.; Lippens Jr., B.C.; Gellings, P.J.; Burggraaf, A.J.

    1987-01-01

    A study of the preparative variables in the synthesis of ceramics based on Bi2O3-Er2O3 solid solutions has shown that the best results are obtained with a coprecipitation method. Critical parameters in the synthesis are found to be i) wet milling of the precalcined powder with an appropriate liquid

  10. Design Considerations of Polishing Lap for Computer-Controlled Cylindrical Polishing Process

    Science.gov (United States)

    Khan, Gufran S.; Gubarev, Mikhail; Speegle, Chet; Ramsey, Brian

    2010-01-01

    The future X-ray observatory missions, such as International X-ray Observatory, require grazing incidence replicated optics of extremely large collecting area (3 m2) in combination with angular resolution of less than 5 arcsec half-power diameter. The resolution of a mirror shell depends ultimately on the quality of the cylindrical mandrels from which they are being replicated. Mid-spatial-frequency axial figure error is a dominant contributor in the error budget of the mandrel. This paper presents our efforts to develop a deterministic cylindrical polishing process in order to keep the mid-spatial-frequency axial figure errors to a minimum. Simulation studies have been performed to optimize the operational parameters as well as the polishing lap configuration. Furthermore, depending upon the surface error profile, a model for localized polishing based on dwell time approach is developed. Using the inputs from the mathematical model, a mandrel, having conical approximated Wolter-1 geometry, has been polished on a newly developed computer-controlled cylindrical polishing machine. We report our first experimental results and discuss plans for further improvements in the polishing process.

  11. Between Polish Positivism and American Capitalism: The Educational Agents' Experiment in the Polish-American Community, 1889-1914

    Science.gov (United States)

    Jaroszynska-Kirchmann, Anna D.

    2008-01-01

    "Ameryka-Echo" was one of the most popular Polish-language weeklies, published in the United States between 1889 and 1972. Its founder and owner, Antoni A. Paryski, consciously sought to transplant ideas of Polish Positivism to the Polish-American immigrant communities in the United States. Reading was a central concept of…

  12. Cure kinetics, morphologies, and mechanical properties of thermoplastic/MWCNT modified multifunctional glassy epoxies prepared via continuous reaction methods

    Science.gov (United States)

    Cheng, Xiaole

    The primary goal of this dissertation is to develop a novel continuous reactor method to prepare partially cured epoxy prepolymers for aerospace prepreg applications with the aim of replacing traditional batch reactors. Compared to batch reactors, the continuous reactor is capable of solubilizing and dispersing a broad range of additives including thermoplastic tougheners, stabilizers, nanoparticles and curatives and advancing epoxy molecular weights and viscosities while reducing energy consumption. In order to prove this concept, polyethersulfone (PES) modified 4, 4'-diaminodiphenylsulfone (44DDS)/tetraglycidyl-4, 4'-diaminodiphenylmethane (TGDDM) epoxy prepolymers were firstly prepared using both continuous reactor and batch reactor methods. Kinetic studies confirmed the chain extension reaction in the continuous reactor is similar to the batch reactor, and the molecular weights and viscosities of prepolymers were readily controlled through reaction kinetics. Atomic force microscopy (AFM) confirmed similar cured network morphologies for formulations prepared from batch and continuous reactors. Additionally tensile strength, tensile modulus and fracture toughness analyses concluded mechanical properties of cured epoxy matrices produced from both reactors were equivalent. Effects of multifunctional epoxy compositions on thermoplastics phase-separated morphologies were systematically studied using a combination of AFM with nanomechanical mapping, spectroscopic and calorimetric techniques to provide new insights to tailor cured reaction induced phase separation (CRIPS) in multifunctional epoxy blend networks. Furthermore, how resultant crosslinked glassy polymer network and phase-separated morphologies correlated with mechanical properties are discussed in detail. Multiwall carbon nanotube (MWCNT)/TGDDM epoxy prepolymers were further prepared by combining the successful strategies for advancing epoxy chemistries and dispersing nanotubes using the continuous reactor

  13. Tooth polishing: Relevance in present day periodontal practice

    Directory of Open Access Journals (Sweden)

    Madan Charu

    2009-01-01

    Full Text Available Time has seen the emergence of more efficient and effective devices like jet abrasives. However, the role of rubber cups with prophy angles cannot be overlooked as they are still being widely used and provide an economical alternative. Owing to several shortcomings associated with the air polishing device using sodium bicarbonate (NaHCO 3 , trends are shifting towards the usage of low abrasive powders. Recent demonstration of Glycine Powder Air Polishing (GPAP in removing subgingival biofilm results in less gingival erosion than hand instrumentation or NaHCO 3 air-polishing. Despite the emergence of latest advances in polishing, data suggesting selective polishing of teeth is compelling.

  14. Monitoring of Robot Assisted Polishing through parameters of acoustic emission

    DEFF Research Database (Denmark)

    Lazarev, Ruslan; Top, Søren; Bilberg, Arne

    The polishing process is essential for the surface generation of machine tooling components in advanced manufacturing. While robot assisted polishing is faster and more consistent than manual polishing, it can still consume a significant part of ma- chining time and operator presence time....... The determination of the point in time to change a polishing media or stop the process is needed for computer controlled functional surface generation. During the last years, several research works have been done in order to build grinding/polishing monitoring systems to determine process characteristics...

  15. Evidence and analysis of parallel growth mechanisms in Cu{sub 2}O films prepared by Cu anodization

    Energy Technology Data Exchange (ETDEWEB)

    Caballero-Briones, F., E-mail: fcaballerobriones@ub.ed [Department of Physical Chemistry, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); CIBER-BBN, Maria de Luna 11, 50018 Zaragoza (Spain); Palacios-Padros, A. [Department of Physical Chemistry, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Calzadilla, O. [Facultad de Fisica, Universidad de La Habana, San Lazaro y L, Colina Universitaria, 10400 Vedado, La Habana (Cuba); Sanz, Fausto, E-mail: fsanz@ub.ed [Institute for Bioengineering of Catalonia (IBEC), Edifici Helix, Baldiri i Reixac 15-21, 08028 Barcelona (Spain); Department of Physical Chemistry, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); CIBER-BBN, Maria de Luna 11, 50018 Zaragoza (Spain)

    2010-05-30

    We have studied the preparation of Cu{sub 2}O films by copper anodization in a 0.1 M NaOH electrolyte. We identified the potential range at which Cu{sup +} dissolution takes place then we prepared films with different times of exposure to this potential. The morphology, crystalline structure, band gap, Urbach energy and thickness of the films were studied. Films prepared with the electrode unexposed to the dissolution potential have a pyramidal growth typical of potential driven processes, while samples prepared at increasing exposure times to dissolution potential present continuous nucleation, growth and grain coalescence. We observed a discrepancy in the respective film thicknesses calculated by coulometry, atomic force microscopy and optical reflectance. We propose that anodic Cu{sub 2}O film formation involves three parallel mechanisms (i) Cu{sub 2}O nucleation at the surface, (ii) Cu{sup +} dissolution followed by heterogeneous nucleation and (iii) Cu{sup +} and OH{sup -} diffusion through the forming oxide and subsequent reaction in the solid state.

  16. Fusion - 2050 perspective (in Polish)

    CERN Document Server

    Romaniuk, R S

    2013-01-01

    The results of strongly exothermic reaction of thermonuclear fusion between nuclei of deuterium and tritium are: helium nuclei and neutrons, plus considerable kinetic energy of neutrons of over 14 MeV. DT nuclides synthesis reaction is probably not the most favorable one for energy production, but is the most advanced technologically. More efficient would be possibly aneutronic fusion. The EU by its EURATOM agenda prepared a Road Map for research and implementation of Fusion as a commercial method of thermonuclear energy generation in the time horizon of 2050.The milestones on this road are tokomak experiments JET, ITER and DEMO, and neutron experiment IFMIF. There is a hope, that by engagement of the national government, and all research and technical fusion communities, part of this Road Map may be realized in Poland. The infrastructure build for fusion experiments may be also used for material engineering research, chemistry, biomedical, associated with environment protection, power engineering, security, ...

  17. The influence of finishing/polishing time and cooling system on surface roughness and microhardness of two different types of composite resin restorations

    OpenAIRE

    Kaminedi, Raja Rajeswari; Penumatsa, Narendra Varma; Priya, Tulasi; Baroudi, Kusai

    2014-01-01

    Objective: The aim of this study was to evaluate the effect of finishing time and polishing time on surface roughness and microhardness of nanofilled and hybrid resin composites. Materials and Methods: Hundred disk composite specimens from micro hybrid composite and nanohybrid composite were prepared, 50 for each type of composite. The specimens were divided into five groups according to the time of finishing and polishing (immediate, 15 min, 24 h and dry). Composite under the Mylar strip wit...

  18. Influence of mechanical alloying time on the properties of Fe3Al intermetallics prepared by spark plasma sintering

    Institute of Scientific and Technical Information of China (English)

    Chengchang Jia; Qing He; Jie Meng; Lina Guo

    2007-01-01

    The Fe3Al-based intermetallics were prepared by mechanical alloying and spark plasma sintering (SPS), and the influence of milling time on the properties of materials was investigated. The phase identification was investigated by X-ray, and the surface morphology and fractography were observed by scanning electron microscope (SEM). The mechanical properties such as bending strength, strain, and microhardness were tested. The results show that Fe reacts with Al completely to form Fe3Al during short SPS processing time. The relative densities of the sintered samples were nearly 100%. The mechanical properties of the sintered samples can be improved along with the milling time. The representative values are the bend strength of 1327 MPa and the microhardness of 434.

  19. Morphology and microstructure characterization of 95W-3.5Ni-1.5Fe powder prepared by mechanical alloying

    Institute of Scientific and Technical Information of China (English)

    Islam S. Humail; Xuanhui Qu; Chengchang Jia; Mingli Qin; Xinbo He

    2006-01-01

    The mechanism of mechanical solid-state reactions for formation of tungsten heavy alloy powder was discussed. A highenergy ball mill operating at room temperature was used for preparing tungsten heavy alloy powders, starting from elemental tungsten (W), nickel (Ni), and iron (Fe) powders. X-ray diffraction (XRD), particle size analyzer, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to follow the progress of the mechanical solid-state reaction of W, Ni, and Fe powders. These morphological studies revealed three stages in the milling process. In the first stage, the particle deformation changes the irregular structure of the as-received powder particles to flattened morphology, and the average particle size increases. In the second stage, the powder is sufficiently deformed and the tendency to fracture predominates over welding, and the particle size decreases. With continuous milling, the system reaches steady state, and relatively small and uniform particle size distribution is obtained after 20 h of milling.

  20. Separation of mercury in industrial processes of Polish hard steam coals cleaning

    OpenAIRE

    Wierzchowski Krzysztof; Pyka Ireneusz

    2016-01-01

    Coal use is regarded as one of main sources of anthropogenic propagation of mercury in the environment. The coal cleaning is listed among methods of the mercury emission reduction. The article concerns the statistical assessment of mercury separation between coal cleaning products. Two industrial processes employed in the Polish coal preparation plants are analysed: coal cleaning in heavy media vessels and coal cleaning in jigs. It was found that the arithmetic mean mercury content in coarse ...

  1. Approaches to the teaching of introductory literature courses in a Polish English Language Teacher Training College.

    OpenAIRE

    2013-01-01

    The purpose of this paper is to outline approaches to a course entitled Introduction to Literature, which is frequently available to second-year undergraduates in Polish teacher training colleges and other institutes of higher education. While preparing students for subsequent courses in British and American literature and helping them towards mature responses to literary texts, the course aims to raise student teachers' awareness of the potential of literature in the learning/teaching situ...

  2. Study on preparation and mechanical performance of TPU/nonwoven composites

    Science.gov (United States)

    Sun, X. C.; Xi, B. J.

    2016-07-01

    In order to study the influence of resin content and layer sequence parameters on the mechanical properties of TPU/non-woven composite materials synthesized by moulding pressing technology. The effects of the resin content and layer sequence on composites were discussed. Through experiments and theoretical analysis, it was revealed how resin content, layer sequence impact on mechanical properties of composite. The mechanics properties of TPU/non-woven composite materials are improved. The process is pressure 0.5 MPa, temperature 110 °C and time 120s min. The melting of the TPU infiltrated into the fabric and filled the space between the fibers.

  3. Mechanical electrodeposition of bright nanocrystalline nickel

    Institute of Scientific and Technical Information of China (English)

    ZHU ZengWei; ZHU Di; QU NingSong

    2008-01-01

    A new mechanical electrodeposition technology was proposed,and nanocrystal-line nickel deposit with bright and smooth surface was prepared in the bath without any additive agents.Unlike traditional methods,the novel technology employed dynamical hard particles to continuously polish the cathode surface and disturb the nearby solution during electrodepositing.Experimental results showed that the polishing effect of hard particles can effectively prevent the hydrogen bubbles and impurities from adhering on the deposit surface and avoid the production of pits,pinholes and nodules.Furthermore,comparing with the deposit prepared by tradi-tional methods,the one prepared by the novel technology was substantially refined with grain size ranging from 30 to 80 nm.Every diffraction peak's intensity of the deposit was reduced,the preferential orientation degree of (200) decreased and those of (111) and (220) increased.The microhardness notably increased.The magnetic properties were also changed with decreased saturation magnetization and increased coercive force.It was also found that variation of current density and cathode rotational speed could affect the structure and properties of the nickel deposits prepared by this technology.Key.words:electrodeposition,electroforming,hard particle,nanocrystalline,bright nickel deposits prepared by this technology.

  4. The thermal decomposition studies of three Polish bituminous coking coals and their blends

    Energy Technology Data Exchange (ETDEWEB)

    Krzesinska, M.; Szeluga, U.; Czajkowska, S.; Muszynski, J.; Zachariasz, J.; Pusz, S.; Pilawa, B. [Centre of Polymer and Carbon Materials, Polish Academy of Sciences, Marii Curie-Sklodowskiej 34, 41-819 Zabrze (Poland); Kwiecinska, B. [AGH-University of Science and Technology, Aleja Mickiewicza 30, 30-059 Krakow (Poland); Koszorek, A. [Department of Inorganic Chemistry and Technology, Silesian Technical University, Krzywoustego 6, 44-100 Gliwice (Poland)

    2009-01-31

    The objective of this work was to investigate the thermal decomposition of various bituminous coal blends. Three Polish coals of varying rank (82.7, 86.2 and 88.7 wt.% carbon content) and caking ability (weak, moderate and strong) were collected from the Krupinski, Szczyglowice and Zofiowka mines, respectively. These coals were used to prepare binary and ternary blends. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used. The weight loss and heat flow during pyrolysis, and storage/loss elastic modulus measured as a function of increasing temperature were related to the caking ability of coals. Parameters determined with the TGA and the DSC methods in the binary and ternary blends were correlated with the proportion of strongly-caking-coal concentration in the blend. The weight loss of coal blends was found to be additive parameter. The DSC thermograms of binary blends were found to be different from those of the ternary blends, which suggests a different course for this blend pyrolysis. (author)

  5. Polish Government policy for coal (1989-2006)

    Energy Technology Data Exchange (ETDEWEB)

    Piotr Zientara

    2007-07-01

    The purpose of this paper is to discuss and assess the consecutive Governments' policy for coal (1989-2006) in the context of the systemic transformation of the Polish economy. The paper presents a critical analysis of the rationale and effectiveness of government efforts to restructure the Polish coal mining industry in the light of economic theory, published literature, and a survey of three collieries. Some parallels, toutes proportions gardees, are drawn between the situation in the UK under Margaret Thatcher and that in Poland. The paper argues that, despite throwing billions of zlotys at the industry in the form of direct subsidies and debt write-offs, decision makers failed to make the collieries economically sound. The weaknesses of the consecutive governments - manifesting itself, amongst other things, in the unwillingness and/or inability to confront the miners' unions, to introduce market mechanisms into the sector, to ensure competent management and, crucially, to press on with nationwide economic liberalisation - are seen as the principal reasons behind the failure.

  6. Surface roughness and hardness of a composite resin: influence of finishing and polishing and immersion methods

    Directory of Open Access Journals (Sweden)

    Ana Luísa Botta Martins de Oliveira

    2010-09-01

    Full Text Available This study evaluated the finishing and polishing effect on the surface roughness and hardness of the Filtek Supreme XT, in fluoride solutions. Specimens were prepared (n = 140 with half of the samples finished and polished with Super-Snap® disks. The experimental groups were divided according to the presence or absence of finishing and polishing and immersion solutions (artificial saliva, sodium fluoride solution at 0.05% - manipulated, Fluordent Reach, Oral B, Fluorgard. The specimens remained immersed in artificial saliva for 24 hours and were then subjected to initial analysis (baseline of surface roughness and Vickers microhardness. Next, they were immersed in different fluoride solutions for 1 min/day, for 60 days. Afterwards, a new surface roughness and microhardness reading was conducted. The data were submitted to a two-way ANOVA and Tukey's test (5% significance level. For the comparison of mean roughness and hardness at baseline and after 60 days, the paired Student t test was used. The results showed that the surface roughness and microhardness of the Filtek Supreme XT were influenced by the finishing and polishing procedure, independently of the immersion methods.

  7. 2D laminated cylinder-like BiFeO3 composites: Hydrothermal preparation, formation mechanism, and photocatalytic properties

    Science.gov (United States)

    Gao, Xiaoming; Dai, Yuan; Fu, Feng; Hua, Xiufu

    2016-12-01

    BiFeO3 perovskite with 2D laminated cylinder-like structure was prepared via a facile one-pot hydrothermal method, whose morphologies and optical properties was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion spectrum (EDS), and UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS). The photocatalytic properties of the as-prepared BiFeO3 composites were evaluated according to degrading Rhodamine B (RhB) and desulfurization under visible light irradiation, with excellent photocatalytic degradation and desulfurization activity found. Moreover, the mechanism study of active free radicals in photocatalytic activity indicates that the h+ radical in holes was mainly responsible for synergistic catalytic efficacy in photocatalytic degradation.

  8. Mechanized methods for preparation and processing of compost from pruning residues in fruit-vine production

    OpenAIRE

    2011-01-01

    This paper is part of research about the effects of mechanized process of fragmentation of pruning residues on the composting process. Compost, as a form of organic fertilizer, requires specific production treatment depending on the form of biomass. Pruning residues from fruit-vine production can be translated into quality organic fertilizer, but it is necessary to coordinate mechanized treatment of biomass and technology of composting process with microbiological processes for organic matter...

  9. Synthesis, characterization, and microwave absorption properties of Fe-40 wt%Ni alloy prepared by mechanical alloying and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jun [College of Materials Science and Engineering, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing 210009 (China); Feng Yongbao, E-mail: fengyongbao@163.com [College of Materials Science and Engineering, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing 210009 (China); Qiu Tai [College of Materials Science and Engineering, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing 210009 (China)

    2011-12-15

    Fe-40 wt%Ni alloys with granular shape and flake shape were prepared by a mechanical alloying (MA) and annealing method. The phase composition and morphology of the FeNi alloys, electromagnetic parameters, and microwave absorbing properties of the silicone rubber composite absorbers filled with the as-prepared FeNi alloy particles were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) and vector network analyzer. The XRD results indicate that the crystalline structures of the Fe-40 wt%Ni alloys prepared by both one-step and two-step MA processes are face-centered cubic (fcc) Ni (Fe) solid solutions, and the structures can be retained after annealing at 600 deg. C for 2 h. SEM images show that the FeNi alloy powders for one-step process have a granular shape; however the particles turned into flake form when they were sequentially milled with absolute ethyl alcohol. With the increase in thickness of composite absorber, the reflection loss (RL) decreases, and the peak for minimum reflection loss shifts towards the lower frequency range. Compared to the absorbers filled with the granular FeNi alloy, the absorbers filled with flaky FeNi alloys possess higher complex permittivities and permeabilities and have a lower RL and peak frequency under the same thickness. Microwave absorbing materials with a low reflection loss peak in the range of 1-4 GHz are obtained, and their microwave absorbing properties can be adjustable by changing their thicknesses. - Highlights: > We prepare face-centered cubic (FCC) Ni (Fe) solid solutions by mechanical alloying and annealing. > Shape of FeNi alloy powder changes from granular to flaky after wet-milling. > Absorbers containing flaky FeNi alloys possess higher electromagnetic parameters. > MAMs with low reflection loss peak in the range of 1-4 GHz are obtained. > Microwave absorbing properties can be adjustable by modifying the thickness of the absorbers.

  10. Corrosion behaviour of polished and sandblasted titanium alloys in PBS solution.

    Science.gov (United States)

    Burnat, Barbara; Walkowiak-Przybyło, Magdalena; Błaszczyk, Tadeusz; Klimek, Leszek

    2013-01-01

    In this work, we performed comparative studies of the effect of surface preparation of Ti6Al4V and Ti6Al7Nb biomedical alloys and the influence of endothelial cells on their corrosion behaviour in PBS (Phosphate Buffered Saline). Two different methods of surface modification were applied - polishing and sandblasting. The polished Ti6Al7Nb alloy was found to have the best resistance against general corrosion in PBS. It was characterized by the lowest corrosion rate, the widest passive range and the lowest reactivity. Both alloys prepared by sandblasting exhibited worse corrosion properties in comparison to the polished ones. This can be associated with a greater development of their surface and the presence of Al2O3 grains which caused an increase of corrosion potential but might also influence the weakening of the passive layer. Results of potentiodynamic anodic polarization indicated that more resistant to pitting corrosion was Ti6Al7Nb alloy regardless of the method of surface preparation. In those cases, anodic polarization caused only an increase of passive layer, while in the case of sandblasted Ti6Al4V alloy it caused a pitting corrosion. The results obtained allowed us to conclude that the niobium-titanium alloys had higher corrosion resistance than titanium alloys with vanadium. Moreover, it was stated that endothelial cells improved the corrosion resistance of all the titanium alloys examined.

  11. Investigation of the sample preparation and curing treatment effects on mechanical properties and bioactivity of silica rich metakaolin geopolymer.

    Science.gov (United States)

    Catauro, M; Bollino, F; Papale, F; Lamanna, G

    2014-03-01

    In many biomedical applications both the biological and mechanical behaviours of implants are of relevant interest; in the orthopaedic field, for example, favourable bioactivity and biocompatibility capabilities are necessary, but at the same time the mechanical characteristics of the implants must be such as to allow one to support the body weight. In the present work, the authors have examined the application of geopolymers with composition H24AlK7Si31O79 and ratio Si/Al=31 to be used in biomedical field, considering two different preparation methods: one of the activators (KOH) has been added as pellets in the potassium silicate solution, in the other as a water solution with 8M concentration. Moreover, a different water content was used and only some of the synthesized samples were heat treated. The chemical and microstructural characterizations of those materials have been carried out by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Subsequently, the effects of the adopted preparation on the mechanical and biological properties have been studied: compressive strength tests have demonstrated that more fragile specimens were obtained when KOH was added as a solution. The bioactivity was successfully evaluated with the soaking of the samples in a simulated body fluid (SBF) for 3 weeks. The formation of a layer of hydroxyapatite on the surface of the materials has been shown both by SEM micrographs and EDS analyses.

  12. Piezoelectric polymer foams: transducer mechanism and preparation as well as touch-sensor and ultrasonic-transducer properties

    Science.gov (United States)

    Wegener, M.

    2010-04-01

    Different materials provide a mechanical-electrical energy conversion and are thus interesting candidates for piezoelectric sensors and actuators. Beside ferroelectric ceramics and polymers, also polymer foams, so-called ferroelectrets, are developed as piezoelectric active materials. Their piezoelectricity originates from optimized structural and elastic-foam properties accompanied with an optimized charge trapping at the polymer layers within the foam structure. The piezoelectric activity arises if mechanical stimuli lead to a thickness variation of the electrically charged voids which results in an electrical signal between the connected electrodes on the film surfaces due to the change of internal electric fields. The concept of such a piezoelectric transducer was developed by investigating cellular polypropylene films with different foam structures and thus different elastic properties. Recently, ferroelectrets were prepared from other polymers following the same concept. Different kind of new foaming procedures are developed in order to broaden the range of usable materials as well as to optimize the adjustment of piezoelectric and ultrasonictransducer properties. The paper provides an overview about ferroelectrets, their underlying working mechanism as well as their preparation possibilities. In detail, piezoelectric properties of polypropylene ferroelectrets are described which are usable for pushbutton or touch-pad applications as well as in ultrasonic-transducer applications.

  13. Evolution of the passive film on mechanically damaged nitinol.

    Science.gov (United States)

    Schroeder, Valeska

    2009-07-01

    The corrosion behavior of Nitinol-based medical implants is critical to their success in vivo. Contemporary Nitinol-based medical implants are typically chemically passivated or electrochemically polished to form a protective passive film. However, mechanically formed surfaces caused by handling damage, fretting, or fatigue fracture may also be present on a device in vivo. In this study, mechanically polished surfaces are used to simulate mechanically damaged surfaces such that analytical techniques, including electrochemical impedance spectroscopy, open circuit potential monitoring, X-ray photoelectron spectroscopy (XPS), and Mott-Schottky analysis may be used to monitor the evolution of the passive film on mechanically damaged Nitinol. These mechanically polished Nitinol surfaces are compared with chemically passivated and electrochemically polished Nitinol surfaces and mechanically polished titanium surfaces in phosphate buffered saline solution. The mechanically polished Nitinol exhibits lower impedance at low frequencies, empirically modeled to a thinner film with lower film resistance than chemically passivated and electrochemically polished Nitinol and mechanically polished titanium. Moreover, the passive film on mechanically polished Nitinol continues to develop over time, increasing in its thickness and film resistance. This characterization demonstrates that mechanically formed surfaces may be initially less protective than chemically passivated and electrochemically polished Nitinol surfaces, but continue to become thicker and more resistant to electrochemical reactions with exposure to saline solution.

  14. Preparation and Mechanism of a New Enhanced Flocculant Based on Bentonite for Drinking Water

    Directory of Open Access Journals (Sweden)

    Feng-shan Zhou

    2015-01-01

    Full Text Available Bentonite is characterized by the large specific surface, good adsorption, ion exchange ability, and nontoxicity. An enhanced bentonite base composite flocculant (BTA can be prepared from treating the calcium base bentonite and compositing various functional additives. Bentonite was firstly treated by citric acid, then the talc and activated carbon turned to be acid part and simultaneously the part that was treated by sodium bicarbonate and calcium hydroxide turned to be alkaline part, and finally the acid bentonite part and alkaline bentonite part were mixed up with preground powder of polymeric chloride aluminium (PAC, cationic polyacrylamide (CPAM, ferrous sulfate, and aluminum sulfate, and after all of the processing flocculant BTA was obtained. The optimum preparation process of flocculant BTA has shown 29.5% acid bentonite part, 29.5% alkaline bentonite part, 15% PAC, 1% CPAM, 5% ferrous sulfate, and 20% aluminum sulfate. BTA was used to treat drinking water with high turbidity and metal ion in Karamay City, Xinjiang. The treated water was surely up to the drinking water standard of China in decolorization rate, deodorization rate, heavy metal ion removal rate, and so forth, and contents of residual aluminum ions and acrylamide monomer in drinking water were considerably decreased.

  15. Investigation of the sample preparation and curing treatment effects on mechanical properties and bioactivity of silica rich metakaolin geopolymer

    Energy Technology Data Exchange (ETDEWEB)

    Catauro, M., E-mail: michelina.catauro@unina2.it; Bollino, F.; Papale, F.; Lamanna, G.

    2014-03-01

    In many biomedical applications both the biological and mechanical behaviours of implants are of relevant interest; in the orthopaedic field, for example, favourable bioactivity and biocompatibility capabilities are necessary, but at the same time the mechanical characteristics of the implants must be such as to allow one to support the body weight. In the present work, the authors have examined the application of geopolymers with composition H{sub 24}AlK{sub 7}Si{sub 31}O{sub 79} and ratio Si/Al = 31 to be used in biomedical field, considering two different preparation methods: one of the activators (KOH) has been added as pellets in the potassium silicate solution, in the other as a water solution with 8 M concentration. Moreover, a different water content was used and only some of the synthesized samples were heat treated. The chemical and microstructural characterizations of those materials have been carried out by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Subsequently, the effects of the adopted preparation on the mechanical and biological properties have been studied: compressive strength tests have demonstrated that more fragile specimens were obtained when KOH was added as a solution. The bioactivity was successfully evaluated with the soaking of the samples in a simulated body fluid (SBF) for 3 weeks. The formation of a layer of hydroxyapatite on the surface of the materials has been shown both by SEM micrographs and EDS analyses. - Highlights: • Rich metakaolin geopolymer activated with KOH/K{sub 2}SiO{sub 3} and thermal treatment • Mechanical and bioactivity test to evaluate consolidation and bone bonding ability • Order of addition of reactants and thermal treatment influence mechanical properties.

  16. Mechanical properties of CFF/MC/SF composite prepared using vacuum infusion impregnation method

    Science.gov (United States)

    Xu, Lixin; Jiang, Aixiong; Yang, Zhiwei; Guan, Houbing; Jia, Hong; Min, Mengyu

    Carbon fiber felt (CFF)/microfine cement (MC)/silica fume (SF) composite was fabricated by using vacuum infusion impregnation method to infiltrate mechanically stirred mixing slurry of MC, SF, and water into CFF. MC, SF, and water were mixed, with a water-cement ratio of 0.5, SF was used to in place of MC in percentages of 0%, 5%, 10%, 15%, 20%, 25%, 30% and 35%. Drainage method was used to determine the density of CFF/MC/SF composite. The bending strength and compressive strength of CFF/MC/SF composite were characterized by universal testing machine. The microstructure of the fracture surface of CFF/MC/SF composite was studied by scanning electron microscopy. Toughening mechanism of CFF/MC/SF composite was also analyzed. The results show that the density and mechanical strength of CFF/MC/SF composites first increases and then decreases as SF content increases. Crack propagation process includes several toughening and reinforcing mechanisms, such as, fiber/matrix debonding, fiber bridging, fiber friction, crack deflection, and fiber pull-out. At 20% SF content, the compactness and mechanical strength of the CFF/MC/SF composite are optimum, with density, flexural strength, and compressive strength at 1.53 g/cm3, 51.08 MPa, and 53.56 MPa, respectively.

  17. Lacquer polishing of X-ray optics

    Science.gov (United States)

    Catura, R. C.; Joki, E. G.; Roethig, D. T.; Brookover, W. J.

    1987-01-01

    Techniques for polishing figured X-ray optics by a lacquer-coating process are described. This acrylic lacquer coating has been applied with an optical quality of an eighth-wave in red light and very effectively covers surface roughness with spatial wavelengths less than about 0.2 mm. Tungsten films have been deposited on the lacquer coatings to provide highly efficient X-ray reflectivity.

  18. Polish normalization of the Body Esteem Scale

    Directory of Open Access Journals (Sweden)

    Małgorzata Lipowska

    2014-02-01

    Full Text Available Background Physical attractiveness plays an important part in one’s social functioning. The interest in one’s own appearance have been documented as widespread among the female population, but over the recent years it is more and more often emphasized that concentrating on body appearance concerns men as well. Franzoi and Shields (1984 created the Body Esteem Scale which allows to qualify the subject’s attitude towards his or her own body. The aim of the study was to create a Polish version of the Body Esteem Scale along with the norms for age and sex clusters. Participants and procedure The normalization sample consisted of 4298 participants: 1865 women aged 16 to 80 (M = 29.92; SD = 12.85 and 2433 men aged 16 to 78 (M = 28.74; SD = 11.50. Education levels among the participants were also controlled for. In order to create a Polish version of the Body Esteem Scale, translation was adopted as the adaptation strategy. Like the original one, the Polish scale comprises 35 items grouped into three gender specific subscales. The subscales for women include Sexual Attractiveness, Weight Concern, and Physical Condition, whereas the body esteem of is examined with regards to Physical Attractiveness, Upper Body Strength, and Physical Condition. Results Reliability of subscales was high both for females (Cronbach’s alpha from 0.80 to 0.89 and males (Cronbach’s alpha from 0.85 to 0.88. The given coefficients of reliability cover the original division into subscales adopted by the authors of BES. Conclusions We confirmed high reliability of the Polish version of the Body Esteem Scale, thus we recommend it as a diagnostic tool. Created norms allowed to refer results obtained in the course of research carried out on people with various disorders (e.g. eating disorders or body dysmorphic disorder with population data for corresponding age brackets.

  19. Preparation of Polystryenylphosphonous Acid of Low Polymerization Degree and Influence of Initiators upon the Free Radical Reaction Mechanism

    Institute of Scientific and Technical Information of China (English)

    XiangKaiFU; YanSUI; 等

    2002-01-01

    The polystyrenylphosphonous acid (PSPA) of low polymerization degress was prepared with one step reaction. The reaction mechanism was changed with different initiators. For the reaction with AIBN or BPO as the initiator, therer are 2 or 3 serives of radical reaction chains and 5 or 9 series of polystyrenyl products. The main products are PSPA without or with the fragment of the initiator H[CH(C6H5)-CH2]n-PO2H2 and C6H5CO2-[CH2CH(C6H5)]n-PO2H2 respectively.

  20. Preparation of Polystyrenylphosphonous Acid of Low Polymerization Degree and Influence of Initiators upon the Free Radical Reaction Mechanism

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The polystyrenylphosphonous acid (PSPA) of low polymerization degree was prepared with one step reaction. The reaction mechanism was changed with different initiators. For the reaction with AIBN or BPO as the initiator, there are 2 or 3 series of radical reaction chains and 5 or 9 series of polystyrenyl products. The main products are PSPA without or with the fragment of the initiator H[CH(C6H5)-CH2]n-PO2H2 and C6H5CO2-[CH2CH (C6H5)]n-PO2H2 respectively.

  1. Effect of Composition on Mechanical Properties of Mullite-WC Nano Composites Prepared by Spark Plasma Sintering

    Directory of Open Access Journals (Sweden)

    H. Rajaei

    2016-12-01

    Full Text Available Mullite-WC composites were prepared from Mullite and WC powders by spark plasma sintering at 1400 °C for a holding time of 180 s under 30 MPa. Microstructure, strength, and hardness of the mullite-WC composites were studied. The mullite-WC composite containing 5-20 wt% WC reached over 94 % theoretical density. The strength and Vickers hardness of mullite-(10 wt% WC sintered composite reached maximum values of 298 MPa, and 1589 HV, respectively demonstrating that the introduction of WC significantly enhances the mechanical properties of the mullite matrix.

  2. Interstitial positions of tin ions in alpha-(FerichSn)(2)O-3 solid solutions prepared by mechanical alloying

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Lin, Rong; Nielsen, Kurt

    1997-01-01

    The microstructure of samples of 91, 85, and 71 mol % alpha-Fe-2-O-3-SnO2. prepared by mechanical alloying, has been studied by x-ray diffraction with Rietveld structure refinements, On the basis of the structure refinements to the whole x-ray diffraction patterns for the four as-milled samples......, it is found that tin ions do not substitute iron ions in the solid solution, although this model is generally assumed in the literature. The Sn4+ ions occupy the empty octahedral holes in the lattice of the alpha-Fe2O3 phase....

  3. EFFECTS OF POLISHING PARAMETERS ON MATERIAL REMOVAL FOR CURVED OPTICAL GLASSES IN BONNET POLISHING

    Institute of Scientific and Technical Information of China (English)

    SONG Jianfeng; YAO Yingxue; XIE Dagang; GAO Bo; YUAN Zhejun

    2008-01-01

    The paper firstly analyzes the influence factor on material removal rate of curved optical work-pieces in the bonnet polishing. Then the experiments are conducted to reveal the effects of several polishing parameters on the material removal rate when the spherical optical glasses are polished with different curvature radius, such as the decrement of the bonnet, the rotational speed of the bonnet and the curvature radius of the work-piece's surface using a bonnet trial-manufacturing machine developed by our assignment groups. In the end, the curvilinear relationships between these parameters and the material removal rate are acquired and the laws of the effects on material removal rate in bonnet polishing by several parameters are given. When the spherical-pieces are polished with smaller curvature radius, it is not proportional to either bonnet decrement or bonnet rotational speed as described by the Preston equation although the removal rate increases as the relative velocity or the applied pressure increases. Therefore, for the purpose of calculating more accurately the material removal of the spherical work-pieces, the Preston equation should be modified and studied further.

  4. Poetic Texts in Polish Heritage Language Classes

    Directory of Open Access Journals (Sweden)

    Anna Gąsienica Byrcyn

    2017-03-01

    Full Text Available The use of poetic texts in heritage Polish composition classes offers a resourceful, motivating, and original way of learning the language and culture, primarily by mastering writing skills and understanding Poland’s rich and complex culture. Moreover, poetic texts give an aesthetical beauty and moral values, and the students discover universal truths during their readings and discussions. A chosen poem, such as Adam Mickiewicz’s “Lelije” (Lilies, Teofil Lenartowicz’s “Złoty kubek” (A Golden Cup, or Bolesław Leśmian’s “Urszula Kochanowska” (Ursula Kochanowska, is presented in class for listening exercises, reading, recitation, discussion, and especially creative writing. The students are introduced to the captivating genre of poetry and learn about the cultural and historical content of this work. Then, they write their poem or a composition on the introduced theme. The assessment consists of the student’s originality, the content of the paper, the organization of the paper, and the employment of correct grammatical sentence structure and vocabulary. Consequently, poetic texts immersed in Polish intertextual space are open and may be read in many ways, beyond their initial context, presenting many fascinating interpretations and offering many intellectual attractions. A poem is an excellent learning source for the creativity stage in the art of writing, transmuting elements of the past Polish culture and literature in modern language classes. Students write their own intriguing stories, focusing on their knowledge of the language, and using resourcefulness and creativity.

  5. Robotic Automation in Computer Controlled Polishing

    Science.gov (United States)

    Walker, D. D.; Yu, G.; Bibby, M.; Dunn, C.; Li, H.; Wu, Y.; Zheng, X.; Zhang, P.

    2016-02-01

    We first present a Case Study - the manufacture of 1.4 m prototype mirror-segments for the European Extremely Large Telescope, undertaken by the National Facility for Ultra Precision Surfaces, at the OpTIC facility operated by Glyndwr University. Scale-up to serial-manufacture demands delivery of a 1.4 m off-axis aspheric hexagonal segment with surface precision robots and computer numerically controlled ('CNC') polishing machines for optical fabrication. The objective was not to assess which is superior. Rather, it was to understand for the first time their complementary properties, leading us to operate them together as a unit, integrated in hardware and software. Three key areas are reported. First is the novel use of robots to automate currently-manual operations on CNC polishing machines, to improve work-throughput, mitigate risk of damage to parts, and reduce dependence on highly-skilled staff. Second is the use of robots to pre-process surfaces prior to CNC polishing, to reduce total process time. The third draws the threads together, describing our vision of the automated manufacturing cell, where the operator interacts at cell rather than machine level. This promises to deliver a step-change in end-to-end manufacturing times and costs, compared with either platform used on its own or, indeed, the state-of-the-art used elsewhere.

  6. Can polish university female students swim?

    Directory of Open Access Journals (Sweden)

    Podstawski Robert

    2013-06-01

    Full Text Available Background and aim of the work: There are only few studies in Polish and foreign literature providing solid information on swimming skills of university students. The aim of the study carried out at the University of Warmia & Mazury in Olsztyn was to determine swimming skills of Polish university female students starting their studies. Material and methods: The study was conducted in 2012 on 298 female students of the 1 st year course, at the age of 19 – 20. Anonymous questionnaire was used in the research. Results: It has been shown that almost 72% of the women could not swim at all, and 26% swam poorly. Within the group of women able to swim, the greatest percentage was set by women using classical style (49% and “their own” one (27% and only 13% of the students used crawl, 9% - back stroke and 2% - butterfly style. Of all the women declaring swimming abilities, the biggest percentage (16% could cover the distance of only 20 – 50 m; fewer students (6% covered the distance of 50 – 100 m; and 5% could swim only 20 m. Only a marginal number of students (2% could cover the distance from 100 to 1000 m; none could swim more than 1000 m. Conclusions: The study showed a very pessimistic picture of swimming skills of Polish university female students in respect of the number of women able to swim, their knowledge of swimming styles, and the length of the covered distance.

  7. Characterization and Streptococcus mutans adhesion on air polishing dentin.

    Science.gov (United States)

    Tada, Kazuhiro; Oda, Hirotake; Inatomi, Michitomo; Sato, Soh

    2014-07-01

    Air polishing is known as an effective and time saving tooth cleaning method. However, this method increased surface roughness and bacterial adhesion on dentin surface. The aim of this study was to characterize and examine Streptococcus mutans adhesion on dentin surface after air polishing as compared to the conventional method. The dentin blocks (4 × 4 × 1 mm) were polished by a rubber cup with polishing material (Polishing) and air-polished by 25 μm glycine (G25), 65 μm glycine (G65), and 65 μm sodium bicarbonate (NHC65) microparticles. Surface roughness (Ra) was measured by a laser electron microscope. The amount of adhered S. mutans was quantified using a resazurin reduction assay (alamarBlue(®)). The Ra of G25 and G65 was significantly (p Polishing. However, there was no significant difference in S. mutans adhesion among Polishing, G25, and G65, while NHC65 showed significantly (p polishing using glycine microparticles conditioned S. mutans adhesion on dentin surface in a similar fashion than the conventional method, and less than air polishing using sodium bicarbonate microparticles.

  8. 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.

  9. Preparation, Mechanical, and Thermal Properties of Biodegradable Polyesters/Poly(Lactic Acid Blends

    Directory of Open Access Journals (Sweden)

    Peng Zhao

    2010-01-01

    Full Text Available Series of biodegradable polyesters poly(butylene adipate (PBA, poly(butylene succinate (PBS, and poly(butylene adipate-co-butylene terephthalate (PBAT were synthesized successfully by melt polycondensation. The polyesters were characterized by Fourier transform infrared spectroscopy (FTIR, 1H-NMR, differential scanning calorimetry (DSC, and gel permeation chromatography (GPC, respectively. The blends of poly(lactic acid (PLA and biodegradable polyester were prepared using a twin screw extruder. PBAT, PBS, or PBA can be homogenously dispersed in PLA matrix at a low content (5–20 wt%, yielding the blends with much higher elongation at break than homo-PLA. DSC analysis shows that the isothermal and nonisothermal crystallizabilities of PLA component are promoted in the presence of a small amount of PBAT.

  10. Ultra high strain properties of lanthanum substituted PZT electro-ceramics prepared via mechanical activation

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ajeet, E-mail: jkajeet@yahoo.co.in [Ceramics and Composites Group, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); School of Physics, University of Hyderabad, Hyderabad 500046 (India); Bhanu Prasad, V.V., E-mail: bhanu@dmrl.drdo.in [Ceramics and Composites Group, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); James Raju, K.C., E-mail: kcjrsp@yahoo.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); James, A.R., E-mail: james@dmrl.drdo.in [Ceramics and Composites Group, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)

    2014-06-25

    Highlights: • PLZT comparable with PMN–PT and their hot-pressed counterparts synthesized. • HEM applied for ceramic preparation at reduced sintering temperature. • Strain value (0.27%) comparable to previous reported values for PLZT 8/60/40. • The electric field induced (strain) hysteresis loss was also found to be very less. - Abstract: Substitution of lanthanum at the A sites of perovskite lead zirconate titanate ceramics shows an improvement in the structural and electrical properties. (Pb{sub 0.92}La{sub 0.08})(Zr{sub 0.60}Ti{sub 0.40})O{sub 3} (PLZT 8/60/40) was prepared using high energy mechano-chemical milling. The effect of milling on the microstructure and electrical properties of PLZT 8/60/40 has been studied. X-ray diffraction shows the phase formation after milling itself. TEM was used to measure the particle size. The SEM image of the sintered pellet shows a dense microstructure and the average grain size was found to be <1.5 μm. Electrical properties of the ceramics were characterized. Piezoelectric charge coefficient (d{sub 33}) was found to be 561 pC/N. Resonance studies were performed on poled ceramics and the electromechanical coupling factor was calculated by the resonance method. The PLZT 8/60/40 composition showed a well saturated and uniform P–E hysteresis loop with remanent polarization (P{sub r}) of 33.29 μC/cm{sup 2} and a coercive field (E{sub c}) of 10.57 kV/cm. Electric field induced strain (S–E loop) shows a value of ∼0.27% with minimum loss.

  11. Preparation, bioactivity and mechanism of nano-hydroxyapatite/sodium alginate/chitosan bone repair material.

    Science.gov (United States)

    Liao, Jianguo; Li, Yanqun; Li, Haiyan; Liu, Jingxian; Xie, Yufen; Wang, Jianping; Zhang, Yongxiang

    2017-08-11

    As the major inorganic component of natural bone, nano-hydroxyapatite (n-HA) on its own is limited in its use in bone repair, due to its brittleness. Chitosan (CS) and sodium alginate (SAL) are used to reduce its brittleness and tendency to degradation. However, the compressive strength of the composite is still low, and its biological performance needs further study. Nano-hydroxyapatite/sodium alginate/chitosan (n-HA/SAL/CS) composite was prepared via an in situ synthesis method. Further, we prepared the n-HA/SAL/CS self-setting bone repair material by mixing n-HA/SAL/CS powder with a curing liquid (20 wt.% citric acid). In addition, the in vitro bioactivity and cell cytotoxicity were also explored. Transmission electron microscopy photos revealed that the n-HA crystals were uniformly distributed throughout the polymer matrix. Infrared IR spectroscopy indicated that the HA interacted with the COO- of SAL and NH2- of CS. The compressive strength of the n-HA/SAL/CS bone cement was 34.3 MPa and matched the demands of weight-bearing bones. Soaking in vitro in simulated body fluid demonstrated that the composite material had reasonably good bioactivity, while cytotoxicity tests indicated that the n-HA/SAL/CS cement could promote cell proliferation and was biocompatible. Compressive strength of n-HA/SAL/CS can satisfy the needs of cancellous bone, and in vitro bioactivity and cytotoxicity tests results indicated that the n-HA/SAL/CS composite could act as an optimal bone repair material.

  12. Microstructures and properties of Cr-Cu/W-Cu bi-layer composite coatings prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiaping; Feng, Xiaomei; Shen, Yifu; Chen, Cheng; Duan, Cuiyuan [Nanjing Univ. of Aeronautics and Astronautics (China). Dept. of Materials Science and Technology

    2016-06-15

    Cr-Cu/W-Cu bi-layer coatings with composite structures were fabricated by means of mechanical alloying. The Cr-Cu layer and the W-Cu layer were deposited successively and the as-synthesized bi-layer coating was made up of an inner Cr-Cu layer and an outer W-Cu layer. Microstructures, chemical and phase compositions of the as-prepared coatings were characterized. The results indicated that the bonding between the inner coating and the substrate was improved with the increase of Cu in the raw powder. The annealing treatment of the inner Cr-Cu layer was beneficial to the bonding between the inner Cr-Cu coating and the outer W-Cu coating layer. Mechanical properties such as microhardness, friction and wear resistance were tested. The as-synthesized coating could effectively improve the hardness and wear resistance of the Cu substrate.

  13. Synthesis mechanism of an Al-Ti-C grain refiner master alloy prepared by a new method

    Science.gov (United States)

    Zhang, B. Q.; Lu, L.; Lai, M. O.; Fang, H. S.; Ma, H. T.; Li, J. G.

    2003-08-01

    The mechanisms of in-situ synthesis of an Al-Ti-C grain-refiner master alloy, prepared by adding a powder mixture of potassium titanium fluoride and carbon into an aluminum melt, have been systematically studied. It was found that vigorous reactions occurred at the initial stage of reaction and then slowed down. After about 20 minutes, the reactions, which led the formation of blocky titanium aluminides and submicron titanium carbides in the aluminum matrix, appeared to reach completion. Potassium titanium fluoride reacted with aluminum and carbon at 724 °C and 736 °C, respectively, resulting in the formation of titanium aluminides and titanium carbides in the aluminum matrix as well as in the formation of a low-melting-point slag of binary potassium aluminofluorides. The reaction between potassium titanium fluoride and carbon is believed to be the predominant mechanism in the synthesis of TiC by this method.

  14. Cone-beam computed tomography analysis of the apical third of curved roots after mechanical preparation with different automated systems

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Cesar Augusto Pereira; Pascoalato, Cristina [University of Southern Santa Catarina (UNISUL), Tubarao, SC (Brazil); Meurer, Maria Ines [Federal University of Santa Catarina (UFSC), Florianopolis, SC (Brazil); Silva, Silvio Rocha Correa, E-mail: silvio@foar.unesp.b [Sao Paulo State University (UNESP), Araraquara, SP (Brazil)

    2009-07-01

    The present study evaluated by cone-beam computed tomography (CBCT) the apical canal transportation and centralizing ability of different automated systems after root canal preparation. The mesiobuccal canals of maxillary first molars (n=10 per group) were prepared with: GI - reciprocating system with K-Flexofile; GII - reciprocating system with NiTiFlex files; GIII - rotary system with K3 instruments; GIV - rotary system with RaCe instruments. CBCT scans were taken before and after biomechanical preparation up to a 40.02 diameter. Canal transportation was determined by measuring the smallest distance between the inner canal walls and the mesial and distal sides of the root. The centralization ability corresponded to the difference between the measurements from transportation evaluation, using the linear voxel to voxel method of analysis. The mean transportation was 0.06 +- 0.14 mm, with a tendency to deviate to the mesial side of the root (n=22), with no statistically significant difference among the groups (p=0.4153). The mean centralization index was 0.15 +- 0.65 also without statistically significant difference among the groups (p=0.0881). It may be concluded that apical canal transportation and centralization ability were not influenced by the type of mechanical movement and instruments used. (author)

  15. Preparation and hydrogen storage properties of nanocrystalline TiFe synthesized by mechanical alloying

    Directory of Open Access Journals (Sweden)

    V.Yu. Zadorozhnyy

    2017-02-01

    Full Text Available In this research, the mechanism of mechanical alloying (MA synthesis of TiFe intermetallic compound (IMC from individual components Ti and Fe has been studied. The partition coefficient of the apparent diffusion and the reaction rate constant during MA solid-state synthesis of the TiFe intermetallic compound in a planetary ball mill have been estimated. The results indicate that the apparent diffusion coefficient is close to 10–11 cm2/s that is approximately one order higher than the conventional high temperature diffusion coefficient. The reaction rate constant is close to 1.75·10−6. The relation between the structure and the hydrogen storage properties of MA synthesized IMC TiFe have been briefly discussed.

  16. Relationships between phase morphology and deformation mechanisms in polymer nanocomposite nanofibres prepared by an electrospinning process.

    Science.gov (United States)

    Kim, G M; Lach, R; Michler, G H; Pötschke, P; Albrecht, K

    2006-02-28

    Relationships between phase morphology and mechanical deformation processes in various electrospun polymer nanocomposite nanofibres (PNCNFs) containing different types of one-, two- and three-dimensional nanofiller have been investigated by transmission electron microscopy using in situ tensile techniques. From the study of the phase structure of electrospun PNCNFs, two morphological standard types are classified for the analysis of deformation mechanisms: the binary system (polymer matrix and nanofillers), and the ternary system (polymer matrix, nanofillers and nanopores on the fibres surface). According to these categories, deformation processes have been characterized, and different schematic models for these processes are proposed. The finding of importance in the present work is a brittle-to-ductile transition in polymer nanocomposite fibres during in situ tensile deformation processes. This unique feature in the deformation behaviour of electrospun PNCNFs provides an optimal balance of stiffness, strength and toughness for use as reinforcing elements in a polymer based composite of a new kind.

  17. Effect of Surface Polishing on Mercury Release from Dental Amalgam After Treatment 16% Carbamide Peroxide Gel

    Directory of Open Access Journals (Sweden)

    Z. Khamverdi

    2011-03-01

    Full Text Available Objectives: This study evaluated the effect of surface polishing on mercury release from dental amalgam after treatment with 16% carbamide peroxide gel.Materials and Methods: Ninety-six samples from two different amalgam brands were prepared in truncated cone-shaped PVC polymer molds with an external surface area of 195 mm². Half of the specimens were polished with green and red rubber, a brush and tin oxide paste at low speed. Samples were treated with 16% carbamide peroxide gel intubes containing 3 mL of carbamide peroxide gel and 0.1 mL of distilled water for 14 and 28 hours. Subsequently, carbamide peroxide gel on the sample surfaces was rinsed away with 7.0 mL of distilled water until the volume of each tube increased to 10 mL. Themercury level of each solution was measured using the VAV–440 mercury analyzer system.Considering the surface area of each amalgam disc, mercury amounts were calculated in μg ⁄mm². Data were analyzed using two-way ANOVA.Results: There were significant differences between the mean levels of mercury release from polished vs. unpolished amalgam surfaces after treatment with 16% carbamide peroxide.Increasing the storage time from 14 to 28 hours did not result in significant changes in the amount of mercury release. There was no significant interaction effect between amalgam surface polish and storage time statistically.Conclusion: Polished amalgam restorations release less mercury after treatment with carbamide peroxide bleaching gel in comparison with unpolished amalgam restorations.

  18. Effect of finishing and polishing on color stability of a nanofilled resin immersed in different media

    Directory of Open Access Journals (Sweden)

    Ana Luísa Botta Martins de OLIVEIRA

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate the effect of finishing and polishing on color stability of a nanofilled composite resin (Filtek Z350 XT according to different immersion media.MATERIAL AND METHOD: Composite disks (10 mm diameter, 2 mm thickness were prepared for each group (n = 6 using a stainless steel mold. The groups were divided according to the presence or absence of finishing and polishing procedure and immersion media (artificial saliva, artificial juice- KAPO(r Coca-Cola(rflavors: pineapple, orange, strawberry and grape. The finishing and polishing procedures were performed using Super -Snap(r disks. The specimens were stored in artificial saliva for 24 hours (baseline and were analyzed using a color spectrophotometer by CIELab system. Then, they were immersed in different media for 5 minutes, 3 times a day, every 4 hours during 60 days. They were stored in artificial saliva at 37 ± 1°C during the immersion intervals. After this time, new measure of color was performed. The data were analyzed using Kruskall-Wallis test and Mann- Whitney test. The significance level was 5%.RESULT: The results showed that the finishing/polishing not significantly influence the color stability of resin composite (p > 0.05. There was no statistically significant difference in the color stability of the studied resin after immersion in different media (p > 0.05.CONCLUSION: The finishing and polishing procedures and the immersion media did not have influence on color stability of nanofilled resin Filtek Z350 XT.

  19. The Collection of Questionnaires Concerning Wild Plants on the Digital Platform of the Polish Ethnographic Atlas

    Directory of Open Access Journals (Sweden)

    Agnieszka Pieńczak

    2016-06-01

    Full Text Available The specificity of the Polish Ethnographic Atlas (PEA research work and the potentialities of applying atlas materials have been largely discussed over the last few years. What should be reminded here is that the research activity of the PEA is based on two mainstays: the documentary one (collecting fieldwork materials, museum and library search and the interpretative one (elaborating appropriate systematics which take into account various forms and varieties of the investigated phenomena, preparing maps and concluding on the basis of the spatial ethnographic image. The first stage has been already completed – therefore, the Cieszyn Atlas Unit has rich ethnographic archives, the only one of such a size in Poland. The collection comprises several thousand interview questionnaires, surveys, fieldwork photographs and other archival materials, obtained by Polish ethnologists in the second half of the 20th century nearly all over Poland. The second mainstay of the atlas activity concerns the elaboration of the collected source materials in the form of maps and some corresponding commentaries as well as in the form of special electronic catalogues. What the article aims at is presenting the specificity of the Polish Ethnographic Atlas in the context of documentation, preservation and popularization of cultural heritage of the Polish countryside. Source materials of the Atlas constitute a unique source of rural history and, in contrast to other ethnographic studies, they comprise the whole territory of Poland. Arduously collected over the decades, the Atlas sources are a precious part of the material cultural heritage. Presenting and popularizing them is needed e.g. by local communities, which turn to their cultural roots to build their local/regional/national identity. Currently, the Polish Ethnographic Atlas is starting long-term documentary work concerning scientific processing and popularization of source materials essential for conducting and

  20. The Effect of Different Polishing Methods and Storage Media on Discoloration of Resin Composites

    Directory of Open Access Journals (Sweden)

    Deljoo Z

    2016-06-01

    Full Text Available Statement of Problem: Accumulation of plaque and staining due to a rough surface, and penetration of colourant agents from food and beverages in to the resin composite results in an incomplete polymerization. There is a little information on the effect of finishing and polishing techniques on the discoloration of nanohybrid and microhybrid composites when exposed to staining solutions. Objectives: To determine the degree of surface staining of nanohybrid and microhybrid composites after polishing and immersion in distilled water and two commonly used staining solutions. Materials and Methods: A nanohybrid (Ice; SDI and microhybrid (Gradis direct; GC composites were used. Disc-shaped specimens were prepared and treated with either a matrix finish or polished using Sof-Lex discs (3M/ ESPE and Enhance point (Dentsply. After 24 h immersion in distilled water at 37°C the specimens were polished and colour coefficients (CIE L* a* b* was measured by a spectrophotometer. All specimens were immersed in 37°C distilled water in an incubator for 7 days and colour coefficients were measured again. The colour change (ΔE was calculated using the following formula: ΔE = [(Δa2+(Δb2+(ΔL2] 1/2. The data were analyzed using three-way ANOVA, one-way ANOVA/Tukey HSD and Student’s t-test. Results: There was a significant interaction between resin composites, polishing systems and staining solutions (p 3.3 compared to cola and distilled water.

  1. Effect of two different polishing systems on fluoride release, surface roughness and bacterial adhesion of newly developed restorative materials.

    Science.gov (United States)

    Bayrak, Gokcen Deniz; Sandalli, Nuket; Selvi-Kuvvetli, Senem; Topcuoglu, Nursen; Kulekci, Guven

    2017-06-15

    To evaluate the effects of two different polishing systems on fluoride release, surface roughness and bacterial adhesion of five restorative materials MATERIALS AND METHODS: The study groups were comprised of five different restorative materials, Beautifil II (B); GCP Glass Fill (G); Amalgomer CR (A); Dyract XP (D); Fuji IX GP (F) and 21 specimens were prepared from each material. Each group was divided into three subgroups according to the polishing system: Mylar (control) (C), Sof-lex (S), and Enhance-Pogo (EP). The amount of fluoride release was measured using a fluoride ion-selective electrode and surface roughness was investigated with a profilometer. Bacterial adhesion on the materials was evaluated by optical density readouts for S.mutans on a spectrophotometer. The highest amount of fluoride was released from specimens in the S subgroup of group G during all measurement days. Surface roughness values were significantly lower in subgroup C than the other polishing systems in all study groups except group G (P material groups in both subgroups (S and EP) (P materials especially in glass ionomer-based materials. Proper polishing systems must be chosen according to the structure and composition of materials to provide the best clinical benefits. Additionally, polishing is necessary for GCP Glass Fill materials following the surface coat and heat application. This article stated that polishing promoted a significant increase of fluoride release on restorative materials especially in glass ionomer-based materials. Further, proper polishing systems must be chosen according to the structure and composition of materials to provide the best clinical benefits in terms of fluoride release, surface roughness and bacterial adhesion. © 2017 Wiley Periodicals, Inc.

  2. Preparation and investigation of Al–4 wt% B4C nanocomposite powders using mechanical milling

    Indian Academy of Sciences (India)

    A Alizadeh; E Taheri-Nassaj; H R Baharvandi

    2011-08-01

    Boron carbide nanoparticles were produced using commercially available boron carbide powder (0.8 m).Mechanical milling was used to synthesize Al nanostructured powder in a planetary ball-mill under argon atmosphere up to 20 h. The same process was applied for Al–4 wt% B4C nanocomposite powders to explore the role of nanosize reinforcements on mechanical milling stages. Scanning electron microscopy (SEM) analysis as well as apparent density measurements were used to optimize the milling time needed for completion of the mechanical milling process. The results show that the addition of boron carbide particles accelerate the milling process, leading to a faster work hardening rate and fracture of aluminum matrix. FE-SEM images show that distribution of boron carbide particles in aluminum matrix reaches a full homogeneity when steady state takes place. The better distribution of reinforcement throughout the matrix would increase hardness of the powder. To study the compressibility of milled powder, modified heckel equation was used to consider the pressure effect on yield strength as well as reinforcing role of B4C particles. For better distribution of reinforcement throughout the matrix, , modified heckel equation was used to consider the pressure effect on yield strength as well as reinforcing role of B4C particles.

  3. Efficient Pb(II) removal using sodium alginate-carboxymethyl cellulose gel beads: Preparation, characterization, and adsorption mechanism.

    Science.gov (United States)

    Ren, Huixue; Gao, Zhimin; Wu, Daoji; Jiang, Jiahui; Sun, Youmin; Luo, Congwei

    2016-02-10

    Alginate-carboxymethyl cellulose (CMC) gel beads were prepared in this study using sodium alginate (SA) and sodium CMC through blending and cross-linking. The specific surface area and aperture of the prepared SA-CMC gel beads were tested. The SA-CMC structure was characterized and analyzed via infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Static adsorption experiment demonstrated that Pb(II) adsorption of SA-CMC exceeded 99% under the optimized conditions. In addition, experiments conducted under the same experimental conditions showed that the lead ion removal efficiency of SA-CMC was significantly higher than that of conventional adsorbents. The Pb(II) adsorption process of SA-CMC followed the Langmuir adsorption isotherm, and the dynamic adsorption model could be described through a pseudo-second-order rate equation. Pb(II) removal mechanisms of SA-CMC, including physical, chemical, and electrostatic adsorptions, were discussed based on microstructure analysis and adsorption kinetics. Chemical adsorption was the main adsorption method among these mechanisms. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Polystyrene/nano-SiO2 composite microspheres fabricated by Pickering emulsion polymerization: Preparation, mechanisms and thermal properties

    Directory of Open Access Journals (Sweden)

    W. H. Zhang

    2012-07-01

    Full Text Available We report the preparation, mechanisms and thermal properties of core-shell structured polymer/inorganic nanoparticle composite microspheres prepared by Pickering emulsion polymerization. Stable Pickering emulsion was firstly fabricated by using surface-modified nano-SiO2 particles as stabilizer. And then, two kinds of polystyrene/nano-SiO2 (PS/SiO2 composite microspheres with different sizes and morphologies were synthesized using hydrophobic azobisisobutyronitrile (AIBN and hydrophilic ammonium persulfate (APS as initiator, respectively. The possible mechanisms of Pickering emulsion polymerization initiated by different initiators were proposed according to the results of transmission electron microscope (TEM and scanning electron microscope (SEM. The chemical structure and molecular weight of the composite microspheres were characterized by Fourier transform infrared spectroscopy (FTIR, X-ray diffractometer (XRD and gel permeation chromatography coupled with a multi-angle laser light scattering photometer (GPC-MALLS. Thermogravimetric analysis (TGA and differential scanning calorimeter (DSC were used to comparatively analyze the thermal properties of nanocomposites and corresponding pure polymer. The results indicated that the decomposition temperature and glass transition temperature (Tg of nanocomposites were elevated to a certain degree due to the existence of nano-SiO2.

  5. [Preparation of two poor water soluble drugs - nanoporous ZnO solid dispersions and the mechanism of drug dissolution improvement].

    Science.gov (United States)

    Gao, Bei; Sun, Chang-shan; Zhi, Zhuang-zhi; Wang, Yan; Chang, Di; Wang, Si-ling; Jiang, Tong-ying

    2011-11-01

    Nanoporous ZnO was used as a carrier to prepare drug solid dispersion, the mechanism of which to improve the drug dissolution was also studied. Nanoporous ZnO, obtained through chemical deposition method, was used as a carrier to prepare indomethacin and cilostazol solid dispersions by melt-quenching method, separately. The results of scanning electron microscope, surface area analyzer, fourier transform infra-red spectroscopy, differential scanning calorimeter and X-ray diffraction showed that drugs were implanted into nanopores of ZnO by physical adsorption effect and highly dispersed into nanopores of ZnO in amorphous form, moreover, these nanopores strongly inhibited amorphous recrystallization in the condition of 45 degrees C and 75% RH. In addition, the results of the dissolution tested in vitro exhibited that the accumulated dissolutions of indomethacin and cilostazol solid dispersions achieved about 90% within 5 min and approximately 80% within 30 min. It was indicated in this study that the mechanism of drug dissolution improvement was associated with the effects of nanoporous ZnO carrier on increasing drug dispersion, controlling drug in nanopores as amorphous form and inhibiting amorphous recrystallization.

  6. High polishing selectivity ceria slurry for formation of top electrode in spin-transfer torque magnetic random access memory

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Hao [Advanced Semiconductor Materials and Devices Development Center, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Electronics and Communication Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Lim, Jae-Hyung [Advanced Semiconductor Materials and Devices Development Center, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Nanoscale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Park, Jin-Hyung [Advanced Semiconductor Materials and Devices Development Center, Hanyang University, Seoul 133-791 (Korea, Republic of); Park, Jea-Gun, E-mail: parkjgL@hanyang.ac.kr [Advanced Semiconductor Materials and Devices Development Center, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Electronics and Communication Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2012-11-01

    During the formation of the top electrode (T.E.) in spin-transfer torque magnetic random access memory, a slurry with a high polishing rate of SiO{sub 2} and a low polishing rate of metal (T.E. material) is required in the chemical mechanical planarization application area. We used a ceria-based slurry with a polymeric additive to maintain the high polishing rate of SiO{sub 2} while it suppresses the polishing rate of the T.E. material, tantalum and ruthenium. We found ruthenium showed a significantly higher selectivity than tantalum in the ceria-based slurry. X-ray photoelectron spectroscopy was used to investigate the adsorption characteristics of the polymeric additive on the T.E. material. Except for the adsorbed polymeric additive, we found that zeta potential of the T.E. material played a critical role in determining the polishing selectivity of SiO{sub 2}-to-T.E. material. - Highlights: Black-Right-Pointing-Pointer High selective chemical mechanical planarization (CMP) slurry was investigated. Black-Right-Pointing-Pointer The slurry has a high selectivity of SiO{sub 2}-to-metals like tantalum and ruthenium. Black-Right-Pointing-Pointer Spin-transfer-torque magnetic memory requires such high selectivity slurry. Black-Right-Pointing-Pointer Surface zeta potential was used to explain CMP mechanism. Black-Right-Pointing-Pointer tantalum and ruthenium have different rate-determining steps during CMP.

  7. Texture control and growth mechanism of WSe2 film prepared by rapid selenization of W film

    Science.gov (United States)

    Li, Hongchao; Gao, Di; Li, Kun; Pang, Mengde; Xie, Senlin; Liu, Rutie; Zou, Jianpeng

    2017-02-01

    The tungsten diselenide (WSe2) films with different orientation present unique properties suitable for specific applications, such as WSe2 with a C-axis⊥substrate for optoelectronics and WSe2 with a C-axis // substrate for electrocatalysts. Orientation control of WSe2 is essential for realizing the practical applications. In this letter, a WSe2 film has been prepared via rapid selenization of a magnetron-sputtered tungsten (W) film. The influence of the magnetron-sputtered W film on WSe2 film growth was studied systematically. Scanning electron microscopy, X-ray diffractometry and high-resolution transmission electron microscopy were used to evaluate the morphology, microstructure and phase composition of the W and WSe2 films. The substrate temperature has a significant effect on the W film phase composition, but little effect on the WSe2 film orientation. The WSe2 orientation can be controlled by changing the W film microstructure. A dense W film that is deposited at low pressure is conducive to the formation of WSe2 with a C-axis⊥substrate, whereas a porous W film deposited at high pressure favors the formation of WSe2 with a C-axis // substrate. A growth model for the WSe2 film with different texture has been proposed based on the experimental results. The direction of selenium (Se) vapor diffusion differs at the top and side surfaces. This is a key factor for the preparation of anisotropic WSe2 films. Highly oriented WSe2 films with a C-axis⊥substrate grow from the dense W film deposited at low pressure because Se vapor can only diffuse into the W film from the top surface where it is converted into selenide. Highly oriented WSe2 with a C-axis // substrate can be achieved for the porous W film that is deposited at high pressure because the nanopores provide a fast transmission tunnel for Se vapor diffusion. These findings will contribute to the controlled fabrication of WSe2 film and provide a theoretical basis for its application.

  8. Preparation of Graphene Oxide and Its Mechanism in Promoting Tomato Roots Growth.

    Science.gov (United States)

    Jiao, Jingzhi; Cheng, Fan; Zhang, Xuekun; Xie, Lingli; Li, Zhiyang; Yuan, Chengfei; Xu, Benbo; Zhang, Liming

    2016-04-01

    Graphene oxide is a new kind of nanomaterial. The graphene oxide was prepared and its quality detected by atomic force microscopy (AFM) and transmission electron microscopy (TEM), for better understanding of effects of the nanomaterial on plants. Wild type. (WT) tomato (Solanum lycopersicum) germplasm 'New Yorker' and corresponding transgenic plants (Prd29A::LeNCED1) were treated with prepared graphene oxide. 9-cis-epoxycarotenoid dioxygenase (NCED) is a key gene for ABA biosynthesis and overexpression of the NCED resulted in ABA accumulation and higher drought tolerance. Seminal root length in the WT tomato was longer than that in the control samples when the seedlings were treated with 20 mg/L graphene oxide for 15 days. In contrast, the same treatment resulted in shorter seminal root length in the transgenic plants compared with control samples. The graphene oxide treatments led to lower Superoxide Dismutase (SOD), Peroxidase (POD), Catalase (CAT) activity and Malondialdehyde (MDA) content in the WT and transgenic plants. 20 mg/L graphene oxide treatment also affected the transcript levels of IAA7, IAA4 and IAA10 but the effect on the wild type and corresponding transgenic plants was different. IAA4 transcription level decreased both in the WT and Prd29A::LeNCED1 transgenic plants while the IAA7 transcription level decreased in the transgenic plants and increased in the WT tomato. The IAA10 transcription level decreased in the WT tomato and increased in the Prd29A::LeNCED1 transgenic plants. Graphene oxide treatments resulted in higher transcription level of ABCG25 and ABCG40 in the WT plants but had no significant effect on transgenic plants. The transcription level of NCED in the WT and Prd29A::LeNCED1 transgenic plants treated with graphene oxide increased significantly, however, it was higher in the transgenic plants than in the WT tomato after 15 d treatment, indicating that the graphene oxide activated the rd29A promoter as does drought and salt. The HD

  9. Hydrodynamic modelling in the Polish Zone of the Baltic Sea - an overview of Polish achievements

    Directory of Open Access Journals (Sweden)

    Ewa Jasińska

    2003-03-01

    Full Text Available This paper gives a general overview of Polish experience and achievements with regard to hydrodynamic modelling in the Polish zone of the Baltic Sea. The first work started already at the end of the sixties when the first 1D and 2D hydrodynamic models were set up. With the development of numerical methods and increasing computational power a number of 1D, 2D and 3D models were set up and tested. Global, regional and local models cover the most important water bodies,i.e. the Pomeranian Bay - Szczecin Lagoon and Gulf of Gdansk - Vistula Lagoon systems.

  10. Preparation and mechanism of Fe3O4/Au core/shell super-paramagnetic microspheres

    Institute of Scientific and Technical Information of China (English)

    CUI; Yali

    2001-01-01

    Chitosans with various degrees of deacetylation (D.D.), which were used as standard sample for FTIR determination, were prepared from completely deacetylated chitosan by homogeneous N-acetylation reaction. By combining four probable probe bands, i.e. 1655, 1560, 1380 and 1320 cm-1, eight probable reference bands, i.e. 3430, 2920, 2880, 1425, 1155, 1070, 1030 and 895 cm-1 and two baseline methods, the most suitable ratios Aprobe band/Areference band from IR spectra to determine the degree of acetylation of chitosan were evaluated from 48 combinations to be A1560/A2880, A1560/A2920 and A1655/A3430(A1560/A2880 is mostly recommended). The second baseline method, i.e. linking between adjacent two valleys, was better for measuring the absorbances of 1560 and 1655 cm-1 bands. The determination range of the D.D. (1%-100%) covered almost the whole range. The standard curves with A1560/A2880 and A1655/A3430 were also suitable for the determination of degree of substitution of other N-acylated chitosan, such as N-propionyl chitosan, N-butyryl chitosan and N-hexanoyl chitosan.

  11. Mechanical properties of anorthite based ceramics prepared from kaolin DD2 and calcite

    Directory of Open Access Journals (Sweden)

    A. Harabi

    Full Text Available Abstract Good quality ceramics costs a lot that has limited their use in developing countries. This work was devoted to prepare low-cost and good quality anorthite based ceramics. The proposed composition was 80 wt% kaolin (DD2 type and 20 wt% calcium oxide (CaO. The choice of these raw materials was dictated by their natural abundance coupled with a modified milling system, as another interesting advantage. Previous studies have shown that a simple vibratory multidirectional milling system using bimodal distribution of highly resistant ceramic milling elements has been successfully applied for obtaining fine powders. The influence of the relatively lower sintering temperature, ranging from 800 to 1100 °C, on the porosity and the average pore size (APS have been investigated. The APS and the porosity values of samples sintered at 950 °C were about 1 μm and 4%, respectively. The best Vickers microhardness and 3-point bending strength values for these sintered samples, using this proposed milling system, were 7.1 GPa and 203 MPa, respectively. Finally, the crystalline phase evolution during heat treatment was investigated by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy techniques.

  12. Mechanical, Microstructure and Surface Characterizations of Carbon Fibers Prepared from Cellulose after Liquefying and Curing

    Directory of Open Access Journals (Sweden)

    Xiaojun Ma

    2013-12-01

    Full Text Available In this study, Cellulose-based carbon fibers (CBCFs were prepared from cellulose after phenol liquefaction and curing. The characteristics and properties of CBCFs were examined by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS. The results showed that, with increasing carbonization temperature, the La, Lc, and Lc/d(002 of CBCFs increased gradually, whereas the degree of disorder R decreased. The –OH, –CH2–, –O–C– and phenyl group characteristic absorption peaks of CBCFs reduced gradually. The cross-linked structure of CBCFs was converted into a graphite structure with a six-ring carbon network during carbonization. The surface of CBCFs were mainly comprised of C–C, C–O, and C=O. The tensile strength, carbonization yield and carbon content of CBCFs obtained at 1000 °C were 1015 MPa, 52%, and 95.04%, respectively.

  13. Hydrogen Sorption Behavior of the MgH2-Ni Prepared by Reactive Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    Mustanir Mustanir

    2009-11-01

    Full Text Available Regarding the use of hydrogen in fuel cell for mobile or stationary applications, metal hydrides can offer a high hydrogen volume capacity and a safe alternative compared with liquid storage or with compressed gas. Among the metal hydrides, magnesium is considered as one of potential hydrogen storage materials because of its high capacity (7.6 wt%, lightweight and low cost. However, high work temperature would slow down kinetics reaction and harden activation process limit practical application of Mg-based hydrides as well. Recently, the high energy ball milling was successfully introduced to prepare hydrogen storage materials. In this work, MgH2 catalyzed with Ni nanoparticles was synthesized by planetary type ball milling under high pressure of hydrogen at 100 bar (10 MPa. As a result, small amount of Ni in nanometer scale acts as a suitable catalyst for kinetics improvement of MgH2 which could absorb 5.3 wt% of hydrogen within 5 minutes at 300ºC. It is obvious that small amount Ni (2 mol% has much better catalyst than catalyst in nanoparticle size; and at the same time, it is allowed to reduce the milling process for short time (2 hours.

  14. Research on the Preparation and Mechanism of the Organic Montmorillonite and Its Application in Drilling Fluid

    Directory of Open Access Journals (Sweden)

    Xiaolong Wang

    2015-01-01

    Full Text Available The study focused on the relation of structure, property, and application of composite prepared by organic cation intercalated montmorillonite (Mt. Herein a new kind of green and steady ionic liquid, 1-hexadecyl-3-methylimidazolium chloride monohydrate (C12mimCl, was chosen as the intercalated agent. This study used molecular dynamics (MD modeling to examine the interlayer microstructures of montmorillonite intercalated with C12mimCl. The C12mimCl intercalation was relatively fast with a large rate constant. The process was affected by the initial concentration of the solution; the basal spacing increased to 2.08 nm after intercalation. The coordination of electrostatic interaction and hydrogen bonding expelled water molecules out of the clay gallery and bound the layer together, which led to the dehydration of clay. The intercalation of C12minCl into Mt interlayer space affected rheology of the system and improved various properties. This organic clay composite was environmentally friendly and could be used in drilling fluid system. These models provided insights into the prediction of synthesized organic cationic-clay microstructure and guidelines for relevant engineering applications.

  15. Comparison between the preparation, structure and mechanical properties of long fiber reinforced thermoplastics and short fiber reinforced thermoplastic

    Institute of Scientific and Technical Information of China (English)

    Fang Kun; Yang Jie; Wu Sizhu; Li Mei; Ma Mingtu

    2012-01-01

    This article summarizes the comparison between the preparation, structure and mechanical properties of long fiber reinforced thermoplastics (LFT) and short fiber reinforced thermoplastics (SFT). Both of the experiment and theory results showed that the mechanical properties of long glass fiber reinforced thermoplastics pellets (LGFRT) have been enhanced better than that of short glass fiber reinforced thermoplastics pellets (SGFRT) manufactured by molding procession. After regulation of the relative humidity by 50 % , the mechanical properties of 30 % ( weight percent) short glass fiber content in SFT ( SFT-PA6-SGF30 ) are similar to that of 40 % long glass fiber content in LFT. Howev- er, the density of the latter is about 17 % lower than that of the former. Thus, the corresponding weight of products is reduced by 13 % ;output rate is increased by 21% , and the cost is therefore significantly lowered. And it has the fol- lowing advantages: impact strength is increased by 87 % ; the proportion is reduced by 20 % ; molding cycle is short- ened by 10 % ;materials cost is saved by 20 % -30 % and the final total cost is saved by 30 % -40 %. So LFT (LFT-PP-LGF40) can replace SFT (SFT-PA6-SGF30) with the similar basic mechanical properties under normal tem- perature or 160 ℃ lower.

  16. Comparison of surface roughness of nanofilled and nanohybrid composite resins after polishing with a multi-step technique

    Science.gov (United States)

    Itanto, B. S. H.; Usman, M.; Margono, A.

    2017-08-01

    To compare the surface roughness of nanofilled and nanohybrid composite resins after polishing using a multi-step technique. 40 composite resin specimens were divided into two groups (20 nanofilled specimens using Filtek Z350 XT [group A] and 20 nanohybrid specimens using Filtek Z250 XT [group B]), prepared, and then polished. After immersion in artificial saliva for 24 hours, the surface roughness was measured with a surface roughness tester. The mean surface roughness results along with the standard deviation of group A were 0.0967 μm ± 0.0174, while the results of group B were 0.1217 μm ± 0.0244. Statistically (with p = 0.05), there were significant differences between each group. The surface roughness of a nanofilled composite resin after polishing with a multi-step technique is better than that of a nanohybrid composite resin.

  17. Formation of a deposit on workpiece surface in polishing nonmetallic materials

    Science.gov (United States)

    Filatov, Yu. D.; Monteil, G.; Sidorko, V. I.; Filatov, O. Y.

    2013-05-01

    During the last decades in the theory of machining nonmetallic materials some serious advances have been achieved in the field of applying fundamental scientific approaches to the grinding and polishing technologies for high-quality precision surfaces of electronic components, optical systems, and decorative articles made of natural and synthetic stone [1-9]. These achievements include a cluster model of material removal in polishing dielectric workpieces [1-3, 6-7] and a physical-statistical model of formation of debris (wear) particles and removal thereof from a workpiece surface [8-10]. The aforesaid models made it possible to calculate, without recourse to Preston's linear law, the removal rate in polishing nonmetallic materials and the wear intensity for bound-abrasive tools. Equally important for the investigation of the workpiece surface generation mechanism and formation of debris particles are the kinetic functions of surface roughness and reflectance of glass and quartz workpiece surfaces, which have been established directly in the course of polishing. During the in situ inspection of a workpiece surface by laser ellipsometry [11] and reflectometry [12] it was found out that the periodic change of the light reflection coefficient of a workpiece surface being polished is attributed to the formation of fragments of a deposit consisting of work material particles (debris particles) and tool wear particles [13, 14]. The subsequent studies of the mechanism of interaction between the debris particles and wear particles in the tool-workpiece contact zone, which were carried out based on classical concepts [15, 16], yielded some unexpected results. It was demonstrated that electrically charged debris and wear particles, which are located in the coolant-filled gap between a tool and a workpiece, move by closed circular trajectories enclosed in spheres measuring less than one fifth of the gap thickness. This implies that the probability of the debris and wear

  18. Preparation of a Bimetal Using Mechanical Alloying for Environmental or Industrial Use

    Science.gov (United States)

    Quinn, Jacqueline; Geiger, Cherie; Clausen, Christian

    2013-01-01

    Following the 1976 Toxic Substances Control Act ban on their manufacture, PCBs remain an environmental threat. PCBs are known to bio-accumulate and concentrate in fatty tissues. Further complications arise from the potential for contamination of commercial mixtures with other more toxic chlorinated compounds such as polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Until recently, only one option was available for the treatment of PCB-contaminated materials: incineration. This may prove to be more detrimental to the environment than the PCBs themselves due to the potential for formation of PCDDs. Metals have been used for the past ten years for the remediation of halogenated solvents and other contaminants in the environment; however, zero-valent metals alone do not possess the activity required to dehalogenate PCBs. Palladium has been shown to act as an excellent catalyst for the dechlorination of PCBs with active metals. This invention is a method for the production of a palladium/magnesium bimetal capable of dechlorinating PCBs using mechanical milling/mechanical alloying. Other base metals and catalysts may also be alloyed together (e.g., nickel or zinc) to create a similarly functioning catalyst system. Several bimetal catalyst systems currently can be used for processes such as hydrogen peroxide synthesis, oxidation of ethane, selective oxidation, hydrogenation, and production of syngas for further conversion to clean fuels. The processes for making these bimetal catalysts often involve vapor deposition. This technology provides an alternative to vapor deposition that may provide equally active catalysts. A hydrogenation catalyst including a base material coated with a catalytic metal is made using mechanical milling techniques. The hydrogenation catalysts are used as an excellent catalyst for the dehalogenation of contaminated compounds and the remediation of other industrial compounds. The mechanical milling technique is

  19. Growth Mechanism of Different Morphologies of ZnO Crystals Prepared by Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    Hu Wang; Juan Xie; Kangping Yan; Ming Duan

    2011-01-01

    Different morphologies of zinc oxide (ZnO), including microrods, hexagonal pyramid-like rods and flower-like rod aggregates, had been synthesized, respectively, on glass substrates by controlling the reaction conditions (such as precursor concentration, reaction time and pH value) of hydrothermal method. The morphologies of the as-obtained ZnO were observed with scanning electron microscopy and transmission electron microscopy. Also, the crystalline natures of different ZnO crystals were analyzed with X-ray diffraction. The possible growth mechanism of ZnO crystals with different morphologies was discussed.

  20. Non-alloyed Ni3Al based alloys – preparation and evaluation of mechanical properties

    Directory of Open Access Journals (Sweden)

    J. Malcharcziková

    2013-07-01

    Full Text Available The paper reports on the fabrication and mechanical properties of Ni3Al based alloy, which represents the most frequently used basic composition of nickel based intermetallic alloys for high temperature applications. The structure of the alloy was controlled through directional solidification. The samples had a multi-phase microstructure. The directionally solidified specimens were subjected to tensile tests with concurrent measurement of acoustic emission (AE. The specimens exhibited considerable room temperature ductility before fracture. During tensile testing an intensive AE was observed.