High-energy molecular lasers self-controlled volume-discharge lasers and applications

CERN Document Server

Apollonov, V V

2016-01-01

This book displays the physics and design of high-power molecular lasers. The lasers described are self-controlled volume-discharge lasers. The book explains self-sustained discharge lasers, self-initiated discharge lasers and technical approaches to laser design. Important topics discussed are laser efficiency, laser beam quality and electric field homogeneity. The book contains many new innovative applications.

Control of a laser front wave

International Nuclear Information System (INIS)

Akaoka, K.; Wakaida, I.

1996-01-01

We controlled the laser wave front through a laser beam simulation experiment propagating through medium. Thus, we confirmed that the RMS, defined as the quadratic mean of the laser beam wave front, dropped to the 1/3 - 1/6 of the pre-control value

Polarisation control of DFB fibre lasers

DEFF Research Database (Denmark)

Varming, Poul; Philipsen, Jacob Lundgreen; Berendt, Martin Ole

1998-01-01

The polarisation properties of a distributed feedback (DFB) fibre laser are investigated. It is shown experimentally that the birefringence of the UV induced phase-shift is the dominating effect controlling the polarisation properties of the laser......The polarisation properties of a distributed feedback (DFB) fibre laser are investigated. It is shown experimentally that the birefringence of the UV induced phase-shift is the dominating effect controlling the polarisation properties of the laser...

Femtosecond laser control of chemical reactions

CSIR Research Space (South Africa)

Du Plessis, A

2010-08-31

Full Text Available Femtosecond laser control of chemical reactions is made possible through the use of pulse-shaping techniques coupled to a learning algorithm feedback loop – teaching the laser pulse to control the chemical reaction. This can result in controllable...

Spatiotemporal control of laser intensity

Science.gov (United States)

Froula, Dustin H.; Turnbull, David; Davies, Andrew S.; Kessler, Terrance J.; Haberberger, Dan; Palastro, John P.; Bahk, Seung-Whan; Begishev, Ildar A.; Boni, Robert; Bucht, Sara; Katz, Joseph; Shaw, Jessica L.

2018-05-01

The controlled coupling of a laser to plasma has the potential to address grand scientific challenges1-6, but many applications have limited flexibility and poor control over the laser focal volume. Here, we present an advanced focusing scheme called a `flying focus', where a chromatic focusing system combined with chirped laser pulses enables a small-diameter laser focus to propagate nearly 100 times its Rayleigh length. Furthermore, the speed at which the focus moves (and hence the peak intensity) is decoupled from the group velocity of the laser. It can co- or counter-propagate along the laser axis at any velocity. Experiments validating the concept measured subluminal (-0.09c) to superluminal (39c) focal-spot velocities, generating a nearly constant peak intensity over 4.5 mm. Among possible applications, the flying focus could be applied to a photon accelerator7 to mitigate dephasing, facilitating the production of tunable XUV sources.

Analysis of Hybrid-Integrated High-Speed Electro-Absorption Modulated Lasers Based on EM/Circuit Co-simulation

DEFF Research Database (Denmark)

Johansen, Tom Keinicke; Krozer, Viktor; Kazmierski, C.

2009-01-01

An improved electromagnetic simulation (EM) based approach has been developed for optimization of the electrical to optical (E/O) transmission properties of integrated electro-absorption modulated lasers (EMLs) aiming at 100 Gbit/s Ethernet applications. Our approach allows for an accurate analysis...... of the EML performance in a hybrid microstrip assembly. The established EM-based approach provides a design methodology for the future hybrid integration of the EML with its driving electronics....

Experimental coherent control of lasers

International Nuclear Information System (INIS)

Gordon, R.; Ramsay, A.J.; Cleaver, J.R.A.; Heberle, A.P.

2002-01-01

We experimentally demonstrate coherent control of a laser. A resonant 100-fs optical pulse is injected into a vertical cavity surface emitting laser to introduce a field component with well-defined phase and thereby excite beating oscillations between the transverse lasing modes. By changing the relative phase between two injected pulses, we can enhance or destroy the beating oscillations and select which lasing modes are excited. We discuss resonant pulse injection into lasers and show how mode competition improves controllability by suppressing the phase-sensitive effects of the carriers

Estudo da topografia e da osseointegração de implante de titânio sob ação do LASER, com ou sem deposição de hidroxiapatita, em coelhos

OpenAIRE

Sisti, Karin Ellen

2011-01-01

Objetivo: Estudar a topografia a osseointegração de implantes de titânio sob ação do LASER de alta intensidade com e sem deposição química de hidroxiapatita, em coelhos. Método: Foram utilizados 30 coelhos albinos que receberam em suas tíbias 3 tipos de superfície de implantes: grupo controle(GI) implantes usinados, grupo(GII) irradiado LASER(Yb), e grupo irradiado e depositado hidroxiapatita pelo método biomimético(GIII). Após os períodos de avaliações (30 e 60 dias) os implantes foram subme...

Vibration noise control in laser satellite communication

Science.gov (United States)

Saksonov, Avigdor; Shlomi, Arnon; Kopeika, Norman S.

2001-08-01

Laser satellite communication has become especially attractive in recent years. Because the laser beam width is narrow than in the RF or microwave range, the transmitted optical power may be significantly reduced. This leads to development of miniature communication systems with extremely low power consumption. On the other hand, the laser communication channel is very sensitive to vibrations of the optical platform. These vibrations cause angular noise in laser beam pointing, comparable to the laser beam width. As result, as significant portion of the optical power between transmitter and receiver is lost and the bit error rate is increased. Consequently, vibration noise control is a critical problem in laser satellite communication. The direction of the laser beam is corrected with a fast steering mirror (FSM). In this paper are presented two approaches for the FSM control. One is the feedback control that uses an LQG algorithm. The second is the direct feed- forward control when vibration noise is measured by three orthogonal accelerometers and drives directly the F SM. The performances of each approach are evaluated using MATLAB simulations.

A Computer-Controlled Laser Bore Scanner

Science.gov (United States)

Cheng, Charles C.

1980-08-01

This paper describes the design and engineering of a laser scanning system for production applications. The laser scanning techniques, the timing control, the logic design of the pattern recognition subsystem, the digital computer servo control for the loading and un-loading of parts, and the laser probe rotation and its synchronization will be discussed. The laser inspection machine is designed to automatically inspect the surface of precision-bored holes, such as those in automobile master cylinders, without contacting the machined surface. Although the controls are relatively sophisticated, operation of the laser inspection machine is simple. A laser light beam from a commercially available gas laser, directed through a probe, scans the entire surface of the bore. Reflected light, picked up through optics by photoelectric sensors, generates signals that are fed to a mini-computer for processing. A pattern recognition techniques program in the computer determines acceptance or rejection of the part being inspected. The system's acceptance specifications are adjustable and are set to the user's established tolerances. However, the computer-controlled laser system is capable of defining from 10 to 75 rms surface finish, and voids or flaws from 0.0005 to 0.020 inch. Following the successful demonstration with an engineering prototype, the described laser machine has proved its capability to consistently ensure high-quality master brake cylinders. It thus provides a safety improvement for the automotive braking system. Flawless, smooth cylinder bores eliminate premature wearing of the rubber seals, resulting in a longer-lasting master brake cylinder and a safer and more reliable automobile. The results obtained from use of this system, which has been in operation about a year for replacement of a tedious, manual operation on one of the high-volume lines at the Bendix Hydraulics Division, have been very satisfactory.

Screening Commercially Available Entomopathogenic Biocontrol Agents for the Control of <em>Aethina tumidaem> (Coleoptera: Nitidulidae in the UK

Directory of Open Access Journals (Sweden)

Giles E. Budge

2012-08-01

Full Text Available The Small hive beetle, <em>Aethina tumidaem>, is an invasive pest of honey bees. Indigenous to sub-Saharan Africa, it has now become established in North America and Australia. It represents a serious threat to European honey bees. Commercially available entomopathogenic agents were screened for their potential to control beetle larvae. Entomopathogenic fungi investigated had minimal impact. The nematodes <em>Steinernema> krausseiem> and <em>S. carpocapsaeem> provided excellent control with 100% mortality of larvae being obtained. Sequential applications of the nematodes following larvae entering sand to pupate also provided excellent control for up to 3 weeks. The information gained supports the development of contingency plans to deal with <em>A. tumidaem> should it occur in the UK, and is relevant to the management of Small hive beetle where it is already present.

Controlled laser biochemistry in room-temperature polar liquids by ultrashort laser pulses

DEFF Research Database (Denmark)

Gruzdev, Vitaly; Korkin, Dmitry; Mooney, Brian P.

2018-01-01

Traditional laser methods to control chemical modifications of biomolecules are not applicable under biologically relevant conditions. We report controlled modifications of peptides and insulin by femtosecond laser in water, methanol, and acetonitrile at room temperature...

Microscale vortex laser with controlled topological charge

Science.gov (United States)

Wang, Xing-Yuan; Chen, Hua-Zhou; Li, Ying; Li, Bo; Ma, Ren-Min

2016-12-01

A microscale vortex laser is a new type of coherent light source with small footprint that can directly generate vector vortex beams. However, a microscale laser with controlled topological charge, which is crucial for virtually any of its application, is still unrevealed. Here we present a microscale vortex laser with controlled topological charge. The vortex laser eigenmode was synthesized in a metamaterial engineered non-Hermitian micro-ring cavity system at exceptional point. We also show that the vortex laser cavity can operate at exceptional point stably to lase under optical pumping. The microscale vortex laser with controlled topological charge can serve as a unique and general building block for next-generation photonic integrated circuits and coherent vortex beam sources. The method we used here can be employed to generate lasing eigenmode with other complex functionalities. Project supported by the “Youth 1000 Talent Plan” Fund, Ministry of Education of China (Grant No. 201421) and the National Natural Science Foundation of China (Grant Nos. 11574012 and 61521004).

Laser control of electron matter waves

NARCIS (Netherlands)

Jones, E.; Becker, M.; Luiten, O.J.; Batelaan, H.

2016-01-01

In recent years laser light has been used to control the motion of electron waves. Electrons can now be diffracted by standing waves of light. Laser light in the vicinity of nanostructures is used to affect free electrons, for example, femto-second and atto-second laser-induced electrons are emitted

The effects of different doses of 670 nm diode laser on skin flap survival in rats O efeito de diferentes doses de laser de diodo 670 nm na viabilidade de retalho cutâneo randômico em ratos

Directory of Open Access Journals (Sweden)

Cristiano Schiavinato Baldan

2012-02-01

Full Text Available PURPOSE: To investigate the effects of different low-level laser therapy (LLLT doses on random skin flap rats. METHODS: Forty Wistar rats were randomly divided in four groups. The control group (CG was not irradiated. The experimental groups were irradiated with a diode laser 670 nm with different energies per point: group 2 (G2 with 0.06 J; group 3 (G3 0.15 J and group 4 (G4 0.57 J. The three groups were irradiated in 12 equally distributed points in the cranial skin flap portion. They were submitted to the irradiation during the immediate, first and second postoperative days. The necrosis area was evaluated in the seventh postoperative day. RESULTS: The CG shows 49.35% of necrosis area in the skin flap; G2, 39.14%; G3, 47.01% and G4, 29.17% respectively. There was a significantly difference when G4 was compared with CG`s skin flap necrosis area. CONCLUSION: The low-level laser therapy diode 670 nm with 0.57 J energy per point increases the survival in randomic skin flap rats.OBJETIVO: Investigar os efeitos de diferentes doses de laserterapia de baixa intensidade na viabilidade de retalhos cutâneos randômicos em ratos. MÉTODOS: Quarenta ratos Wistar foram randomizadamente distribuídos em quatro grupos. O grupo controle (GC não foi irradiado. Os animais dos grupos experimentais foram irradiados por laser de diodo (670 nm com as seguintes energias ofertadas por ponto: grupo 2 (G2 0,06J; grupo 3 (G3 0,15 J e grupo 4 (G4 0,57 J. Os três grupos foram irradiados em 12 pontos igualmente distribuídos na porção cranial do retalho cutâneo. Todos os animais dos grupos 2, 3 e 4 foram submetidos ao protocolo de irradiação por três dias consecutivos, iniciando no pós-operatório imediato. A área necrótica foi avaliada no sétimo dia pós-operatório. RESULTADOS: A porcentagem de área necrótica apresentou-se da seguinte forma, nos diferentes grupos: GC= 49,35%, G2= 39,14%, G3= 47,01 e G4= 29,17%. Foi encontrada diferença estatisticamente

Method of controlling chaos in laser equations

International Nuclear Information System (INIS)

Duong-van, M.

1993-01-01

A method of controlling chaotic to laminar flows in the Lorenz equations using fixed points dictated by minimizing the Lyapunov functional was proposed by Singer, Wang, and Bau [Phys. Rev. Lett. 66, 1123 (1991)]. Using different fixed points, we find that the solutions in a chaotic regime can also be periodic. Since the laser equations are isomorphic to the Lorenz equations we use this method to control chaos when the laser is operated over the pump threshold. Furthermore, by solving the laser equations with an occasional proportional feedback mechanism, we recover the essential laser controlling features experimentally discovered by Roy, Murphy, Jr., Maier, Gills, and Hunt [Phys. Rev. Lett. 68, 1259 (1992)

Method of controlling chaos in laser equations

Science.gov (United States)

Duong-van, Minh

1993-01-01

A method of controlling chaotic to laminar flows in the Lorenz equations using fixed points dictated by minimizing the Lyapunov functional was proposed by Singer, Wang, and Bau [Phys. Rev. Lett. 66, 1123 (1991)]. Using different fixed points, we find that the solutions in a chaotic regime can also be periodic. Since the laser equations are isomorphic to the Lorenz equations we use this method to control chaos when the laser is operated over the pump threshold. Furthermore, by solving the laser equations with an occasional proportional feedback mechanism, we recover the essential laser controlling features experimentally discovered by Roy, Murphy, Jr., Maier, Gills, and Hunt [Phys. Rev. Lett. 68, 1259 (1992)].

Real-time control of ultrafast laser micromachining by laser-induced breakdown spectroscopy

International Nuclear Information System (INIS)

Tong Tao; Li Jinggao; Longtin, Jon P.

2004-01-01

Ultrafast laser micromachining provides many advantages for precision micromachining. One challenging problem, however, particularly for multilayer and heterogeneous materials, is how to prevent a given material from being ablated, as ultrafast laser micromachining is generally material insensitive. We present a real-time feedback control system for an ultrafast laser micromachining system based on laser-induced breakdown spectroscopy (LIBS). The characteristics of ultrafast LIBS are reviewed and discussed so as to demonstrate the feasibility of the technique. Comparison methods to identify the material emission patterns are developed, and several of the resulting algorithms were implemented into a real-time computer control system. LIBS-controlled micromachining is demonstrated for the fabrication of microheater structures on thermal sprayed materials. Compared with a strictly passive machining process without any such feedback control, the LIBS-based system provides several advantages including less damage to the substrate layer, reduced machining time, and more-uniform machining features

Fotocoagulação a laser em pacientes portadores de descolamento de retina regmatogênico periférico

Directory of Open Access Journals (Sweden)

Paulo Escarião

2013-08-01

Full Text Available OBJETIVO: Relatar uma série de casos de descolamento de retina sem envolvimento macular tratados com fotocoagulação a laser. MÉTODOS: Estudo tipo série de casos envolvendo 14 olhos de 12 pacientes com descolamento de retina regmatogênico sem envolvimento macular, retrospectivo, de intervenção. Olhos com procedimentos cirúrgicos prévios foram excluídos. A fotocoagulação a laser foi aplicada com três fileiras confluentes de spot de 300μm, posterior ao descolamento de retina, se extendendo até a ora serrata. A melhor acuidade visual corrigida pré e pós-operatória e a progressão do descolamento de retina foram registrados durante o estudo. RESULTADOS: Treze olhos necessitaram de apenas uma sessão de laser para conter o descolamento de retina. Apenas um olho necessitou de intervenção adicional por causa da evolução do descolamento de retina. Miopia foi encontrada em 7 olhos. Todos os pacientes mantiveram acuidade visual corrigida igual ou melhor que 20/30. CONCLUSÃO:Em casos bem selecionados, a fotocoagulação a laser pode ser considerada para o tratamento de descolamento de retina regmatogênico.

Evaluation of muscle regeneration in aged animals after treatment with low-level laser therapy Avaliação da regeneração muscular em animais idosos após tratamento com laser de baixa intensidade

Directory of Open Access Journals (Sweden)

Adriana Pertille

2012-12-01

ável para a regeneração muscular. OBJETIVO: Avaliar o efeito do tratamento com laser de baixa intensidade sobre a regeneração muscular de modelos experimentais idosos após contusão. MÉTODO: Foram utilizados 25 ratos machos, com 18 meses de idade, divididos em três grupos: grupo controle (CT, sem intervenção; grupo lesão (LE, com contusão muscular e sem tratamento e grupo laser (LA, com contusão muscular e tratado com laser de baixa intensidade, 830 nm, 30 mW e 4 J/cm². A contusão foi realizada no músculo tibial anterior, e as amostras coletadas após sete e 21 sessões de tratamento. O músculo foi designado às técnicas de Microscopia de Luz e Immunoblotting. RESULTADOS: Após 21 dias de tratamento, houve redução significativa na área de inflamação/regeneração no grupo LA 21 comparado ao grupo LE 21. Na área de secção transversal das fibras em processo de regeneração, não houve diferença estatística entre os grupos LA e LE. A análise molecular evidenciou que o conteúdo de MyoD apresentou redução significativa no grupo LE 21 em relação ao CT. O conteúdo de Miogenina exibiu aumento no LE 21 comparado ao CT e, por fim, o conteúdo de TGF-β1 do grupo LE 21 aumentou em relação ao grupo CT. CONCLUSÃO: Para os parâmetros utilizados, o laser demonstrou eficácia na regeneração muscular em animais idosos somente por meio do seu efeito anti-inflamatório.

Controle Químico de Antracnose em Mudas de Pupunheira em Viveiro Chemical Control of Anthracnose on Peach Palm Transplants in Orchard

Directory of Open Access Journals (Sweden)

Rudimar Mafacioli

2011-03-01

Full Text Available

Laser Control of Atoms and Molecules

CERN Document Server

Letkhov, V S

2007-01-01

This text treats laser light as a universal tool to control matter at the atomic and molecular level, one of the most exciting applications of lasers. Lasers can heat matter, cool atoms to ultra-low temperatures where they show quantum collective behaviour, and can act selectively on specific atoms and molecules for their detection and separation.

Chaotic dynamics and chaos control in nonlinear laser systems

International Nuclear Information System (INIS)

Fang Jinqing; Yao Weiguang

2001-01-01

Chaotic dynamics and chaos control have become a great challenge in nonlinear laser systems and its advances are reviewed mainly based on the ring cavity laser systems. The principle and stability conditions for time-delay feedback control are analyzed and applied to chaos control in the laser systems. Other advanced methods of chaos control, such as weak spatial perturbation and occasional proportional feedback technique, are discussed. Prospects of chaos control for application (such as improvement of laser power and performance, synchronized chaos secure communication and information processing) are pointed out finally

Computer control of pulsed tunable dye lasers

International Nuclear Information System (INIS)

Thattey, S.S.; Dongare, A.S.; Suri, B.M.; Nair, L.G.

1992-01-01

Pulsed tunable dye lasers are being used extensively for spectroscopic and photo-chemical experiments, and a system for acquisition and spectral analysis of a volume of data generated will be quite useful. The development of a system for wavelength tuning and control of tunable dye lasers and an acquisition system for spectral data generated in experiments with these lasers are described. With this system, it is possible to control the tuning of three lasers, and acquire data in four channels, simultaneously. It is possible to arrive at the desired dye laser wavelength with a reproducibility of ± 0.012 cm -1 , which is within the absorption width (atomic interaction) caused by pulsed dye lasers of linewidth 0.08 cm -1 . The spectroscopic data generated can be analyzed for spectral identification within absolute accuracy ± 0.012 cm -1 . (author). 6 refs., 11 figs

Análise micromorfológica de esmalte e dentina expostos ao laser de Nd: YAG em regime de picossegundos

Directory of Open Access Journals (Sweden)

Lizarelli Rosane de Fátima Zanirato

2002-01-01

Full Text Available A eficiência da ablação com laser através de um regime de picossegundos minimiza a destruição do material adjacente devido à formação de plasma e ataque. Isso previne a geração excessiva de ondas de choque e promove uma considerável diminuição nos efeitos mecânicos. Nesse estudo foi utilizado um laser de Nd:YAG em picossegundo "Q-switched" e "mode-locked" (Antares 76-s, Coherent, Palo Alto, CA, três molares humanos recém-extraídos e foram realizados 15 microcavidades em esmalte e 9 em dentina. Os parâmetros para irradiar o esmalte seguiram uma freqüência fixa de 100 Hz e potência média de 1,3 W; enquanto que para a dentina, a freqüência foi fixa em 15 Hz enquanto que a potência média variou em 800, 700 e 600 mW. O esmalte demonstrou ser mais capaz de dissipar as ondas de choque do que a dentina, uma vez que as trincas originadas nas microcavidades foram mais freqüentes em tecido dentinário, diferentemente do esmalte. Em conclusão, parece que para manter os aspectos de definição de bordas é importante escolher tempos de irradiação mais curtos, quando as potências médias forem mantidas mais altas, ou seja, energia total entregue mais baixa e bem localizada.

Real-time laser cladding control with variable spot size

Science.gov (United States)

Arias, J. L.; Montealegre, M. A.; Vidal, F.; Rodríguez, J.; Mann, S.; Abels, P.; Motmans, F.

2014-03-01

Laser cladding processing has been used in different industries to improve the surface properties or to reconstruct damaged pieces. In order to cover areas considerably larger than the diameter of the laser beam, successive partially overlapping tracks are deposited. With no control over the process variables this conduces to an increase of the temperature, which could decrease mechanical properties of the laser cladded material. Commonly, the process is monitored and controlled by a PC using cameras, but this control suffers from a lack of speed caused by the image processing step. The aim of this work is to design and develop a FPGA-based laser cladding control system. This system is intended to modify the laser beam power according to the melt pool width, which is measured using a CMOS camera. All the control and monitoring tasks are carried out by a FPGA, taking advantage of its abundance of resources and speed of operation. The robustness of the image processing algorithm is assessed, as well as the control system performance. Laser power is decreased as substrate temperature increases, thus maintaining a constant clad width. This FPGA-based control system is integrated in an adaptive laser cladding system, which also includes an adaptive optical system that will control the laser focus distance on the fly. The whole system will constitute an efficient instrument for part repair with complex geometries and coating selective surfaces. This will be a significant step forward into the total industrial implementation of an automated industrial laser cladding process.

Controlling Second Harmonic Efficiency of Laser Beam Interactions

Science.gov (United States)

Barnes, Norman P. (Inventor); Walsh, Brian M. (Inventor); Reichle, Donald J. (Inventor)

2011-01-01

A method is provided for controlling second harmonic efficiency of laser beam interactions. A laser system generates two laser beams (e.g., a laser beam with two polarizations) for incidence on a nonlinear crystal having a preferred direction of propagation. Prior to incidence on the crystal, the beams are optically processed based on the crystal's beam separation characteristics to thereby control a position in the crystal along the preferred direction of propagation at which the beams interact.

Ciclofotocoagulação com laser diodo em glaucoma refratário, resultado a longo prazo Cyclophotocoagulation with diode laser in refractory glaucoma, long-term results

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Vera Christina Waller de Lima

2003-08-01

Full Text Available OBJETIVO: Relatar experiência de longo prazo com ciclofotocoagulação com laser diodo em glaucomas refratários. MÉTODOS: Foram selecionados casos de glaucomas refratários com indicação de ciclofotocoagulação com laser diodo acoplado a uma sonda G (Iris Medical. Todos os procedimentos foram realizados pelo mesmo cirurgião que realizou 20 aplicações (em média com 2000 mW de potência em 270 graus de extensão, com a sonda colocada a 1,5 mm do limbo, por 2,0 a 2,5 s. Foram incluídos somente casos com pelo menos 6 meses de seguimento. Considerou-se sucesso cirúrgico Po final PURPOSE: To report long-term experience with cyclophotocoagulation using diode laser in refractory glaucomas. METHODS: We selected cases of refractory glaucoma with indication for cyclophotocoagulation (CPC with diode laser using a G probe (Iris Medical. All procedures were performed by the same surgeon: twenty applications of 2000 mW power at 270- degree extension. The probe placed set at 1.5 mm from the limbus during 2.0 a 2.5 s. Only cases with at least 6 months of follow-up were included. The procedure was considered successful when IOP was < 24 mmHg or decrease was larger or equal to 30% of the initial IOP with remission of symptoms. Only 25 patients (18.75% concluded the study (36 months. RESULTS: One hundred and thirty cases had a mean follow-up of 18,1 ± 9,6 months with 116 (87.2% successful cases and 17 (12,7% insuccess ful cases. Initial and final IOP were, 48.20 ± 12.11mmHg and 19.93 ± 11,93mmHg respectively (p < 0.0001. Main complications were: "Phthisis bulbi" in 7 (5.2% cases and long-term hypotony in 6 (4.5% cases. CONCLUSIONS: Considering the severity of our cases, we conclude that the long-term results of cyclophotocoagulation with diode laser for refractory glaucomas were satisfactory, with an acceptable incidence of complications.

DFB laser array driver circuit controlled by adjustable signal

Science.gov (United States)

Du, Weikang; Du, Yinchao; Guo, Yu; Li, Wei; Wang, Hao

2018-01-01

In order to achieve the intelligent controlling of DFB laser array, this paper presents the design of an intelligence and high precision numerical controlling electric circuit. The system takes MCU and FPGA as the main control chip, with compact, high-efficiency, no impact, switching protection characteristics. The output of the DFB laser array can be determined by an external adjustable signal. The system transforms the analog control model into a digital control model, which improves the performance of the driver. The system can monitor the temperature and current of DFB laser array in real time. The output precision of the current can reach ± 0.1mA, which ensures the stable and reliable operation of the DFB laser array. Such a driver can benefit the flexible usage of the DFB laser array.

Microdissecção e captura a laser na investigação do gene TP53 em tecidos incluídos em parafina Laser-capture microdissection for TP53 gene analysis in paraffin-embedded tissues

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Shadia Muhammad Ihlaseh

2007-02-01

Full Text Available INTRODUÇÃO: Microdissecção e captura a laser (MCL é uma técnica de desenvolvimento recente que permite a coleta de células individuais ou pequeno conjunto de células para análise molecular. Atualmente, no Brasil, há raros microscópios para MCL, de modo que a divulgação dos procedimentos inerentes a essa técnica é oportuna para destacar seu amplo potencial para diagnóstico e investigação. OBJETIVO: Este trabalho descreve a padronização dos procedimentos de MCL e de extração de DNA de material fixado em formalina e incluído em parafina. MATERIAL E MÉTODOS: Foram estudados o éxon 8 do gene TP53 e o gene da ciclofilina em amostras de tecido normal e de neoplasias de fígado e rim provenientes de modelo de carcinogênese química induzida em rato. A extração do DNA foi comprovada por reação em cadeia da polimerase (nested-PCR. RESULTADOS: Foram padronizados os procedimentos de preparo dos cortes histológicos, de microdissecção e captura a laser e de obtenção de seqüências gênicas pela reação de nested-PCR para tecidos incluídos em parafina. Obtivemos amplificação de 48,3% das amostras para o éxon 8 do gene TP53 e 51,7% para o gene da ciclofilina. Considerando pelo menos um dos dois segmentos gênicos, foram amplificadas 79,3% das amostras. DISCUSSÃO E CONCLUSÃO: A extração de DNA de tecidos fixados em formalina e incluídos em parafina e a técnica de nested-PCR foram adequadamente padronizadas para produtos gênicos de interesse, obtidos de material coletado por MCL. Esses procedimentos podem ser úteis para a obtenção de seqüências de DNA de arquivos para análise molecular.BACKGORUND: Laser-capture micro-dissection (LCM is a recently developed procedure that provides single cells or specific cell groups for molecular analysis. Currently, there are few LCM systems in Brazil, in such a way that it is necessary to disseminate the technical procedures inherent to the methodology, and also to

Microstructural evolution and control in laser material processing

International Nuclear Information System (INIS)

Kaul, R.; Nath, A.K.

2005-01-01

Laser processing, because of its characteristic features, often gives rise to unique microstructure and properties not obtained with other conventional processes. We present various diverse laser processing case studies involving control of microstructure through judicious selection of processing parameters carried out with indigenously developed high power CO 2 lasers. The first study describes microstructural control during end plug laser welding of PFBR fuel pin, involving crack pone alloy D9 tube and type 316 M stainless steel (SS) plug, through preferential displacement of focused laser beam. Crater and associated cracks were eliminated by suitable laser power ramping. Another case study describes how low heat input characteristics of laser cladding process has been exploited for suppressing dilution in 'Colomony 6' deposits on austenitic SS. The results are in sharp contrast to extensive dilution noticed in Colmony 6 hard faced deposits made by GTAW. A novel laser surface melting (LSM) treatment for type 316 (N) SS weld metal has been developed to generate a sensitization-resistant microstructure which leads to enhanced resistance against intergranular corrosion (IGC). IGC resistance of laser treated surface has been found to be critically dependent on laser processing parameters. Experimental observations have been analyzed with thermal simulation. We have also studied the effect of laser beam spatial intensity profile on the microstructure in LSM. We have developed laser-assisted graded hard facing of austenitic SS substrate with Stellite 6 which, in contrast to direct deposition either by laser or GTAW, produced smooth transition in chemical composition and hardness used to control grain coarsening and martensite formation in type 430 SS weldment. Laser rapid manufacturing (LRM) is emerging as a new rapid and cost effective process for low volume fabrication, esp. of expensive materials. The talk will also present microstructural characteristics of laser

High-powered CO2 -lasers and noise control

Science.gov (United States)

Honkasalo, Antero; Kuronen, Juhani

High-power CO2 -lasers are being more and more widely used for welding, drilling and cutting in machine shops. In the near future, different kinds of surface treatments will also become routine practice with laser units. The industries benefitting most from high power lasers will be: the automotive industry, shipbuilding, the offshore industry, the aerospace industry, the nuclear and the chemical processing industries. Metal processing lasers are interesting from the point of view of noise control because the working tool is a laser beam. It is reasonable to suppose that the use of such laser beams will lead to lower noise levels than those connected with traditional metal processing methods and equipment. In the following presentation, the noise levels and possible noise-control problems attached to the use of high-powered CO2 -lasers are studied.

Estudo comparativo das alterações histológicas imediatas causadas pelo uso do laser de CO2 e do laser de erbium na pele de ratos wistar Comparative study of histopathological abnormalities induced by CO2 and erbium laser on the skin of wistar rats

Directory of Open Access Journals (Sweden)

Lúcia de Noronha

2001-01-01

Full Text Available O presente estudo tem como objetivo analisar, do ponto de vista anatomopatológico, os efeitos térmicos encontrados na pele de ratos wistar após a aplicação do laser de CO2 e do laser erbium. Utilizaram-se oito ratos submetidos a tricotomia em toda a região toracodorsal. Selecionaram-se duas áreas separadas, as quais receberam a aplicação do laser. Na primeira foram realizadas duas passadas do laser de CO2 e na segunda, duas passadas do laser erbium. A área-controle correspondeu àquela imediatamente adjacente à área submetida ao laser. A análise microscópica da lesão causada pelo laser de CO2 revela lesão em forma de U, com ablação completa da epiderme em toda a sua extensão. A derme superficial apresenta degeneração do colágeno, correspondendo ao dano térmico residual, e a transição deste para a derme normal é bem demarcada. Na pele lesada com laser erbium observa-se também extensa área de pele lesada em forma de platô, com algumas pequenas áreas de pele não-lesada. Pode-se observar, ainda, dano do colágeno na derme superficial, porém mais discreto que aquele causado pelo CO2.The aim of this paper is to analyses the histopathology of the termal effects on the skin of Wistar rats after the application of CO2 and erbium laser. Eight rats had their flanks shaved and two areas were selected for the use of the laser. The first area received two applications of CO2 laser, and the second area two applications of the erbium laser. The skin adjacent to the laser application site was used as a control area. The microscopic analysis of the injury caused by CO2 laser revealed a complete ablation of epidermis and an injury that looked like an "U" in shape. The superficial dermis presented a degeneration of the collagen that corresponded to the residual thermal injury, to normal dermis was sharply demarcated. The injury caused by erbium laser was observed as a plateau injured area with a few small normal areas. The collagen

Novel CO2 laser robotic controller outperforms experienced laser operators in tasks of accuracy and performance repeatability.

Science.gov (United States)

Wong, Yu-Tung; Finley, Charles C; Giallo, Joseph F; Buckmire, Robert A

2011-08-01

To introduce a novel method of combining robotics and the CO(2) laser micromanipulator to provide excellent precision and performance repeatability designed for surgical applications. Pilot feasibility study. We developed a portable robotic controller that appends to a standard CO(2) laser micromanipulator. The robotic accuracy and laser beam path repeatability were compared to six experienced users of the industry standard micromanipulator performing the same simulated surgical tasks. Helium-neon laser beam video tracking techniques were employed. The robotic controller demonstrated superiority over experienced human manual micromanipulator control in accuracy (laser path within 1 mm of idealized centerline), 97.42% (standard deviation [SD] 2.65%), versus 85.11% (SD 14.51%), P = .018; and laser beam path repeatability (area of laser path divergence on successive trials), 21.42 mm(2) (SD 4.35 mm(2) ) versus 65.84 mm(2) (SD 11.93 mm(2) ), P = .006. Robotic micromanipulator control enhances accuracy and repeatability for specific laser tasks. Computerized control opens opportunity for alternative user interfaces and additional safety features. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

Laser Controlled Molecular Orientation Dynamics

International Nuclear Information System (INIS)

Atabek, O.

2004-01-01

Molecular orientation is a challenging control issue covering a wide range of applications from reactive collisions, high order harmonic generation, surface processing and catalysis, to nanotechnologies. The laser control scenario rests on the following three steps: (i) depict some basic mechanisms producing dynamical orientation; (ii) use them both as computational and interpretative tools in optimal control schemes involving genetic algorithms; (iii) apply what is learnt from optimal control to improve the basic mechanisms. The existence of a target molecular rotational state combining the advantages of efficient and post-pulse long duration orientation is shown. A strategy is developed for reaching such a target in terms of a train of successive short laser pulses applied at predicted time intervals. Each individual pulse imparts a kick to the molecule which orients. Transposition of such strategies to generic systems is now under investigation

Research on laser cladding control system based on fuzzy PID

Science.gov (United States)

Zhang, Chuanwei; Yu, Zhengyang

2017-12-01

Laser cladding technology has a high demand for control system, and the domestic laser cladding control system mostly uses the traditional PID control algorithm. Therefore, the laser cladding control system has a lot of room for improvement. This feature is suitable for laser cladding technology, Based on fuzzy PID three closed-loop control system, and compared with the conventional PID; At the same time, the laser cladding experiment and friction and wear experiment were carried out under the premise of ensuring the reasonable control system. Experiments show that compared with the conventional PID algorithm in fuzzy the PID algorithm under the surface of the cladding layer is more smooth, the surface roughness increases, and the wear resistance of the cladding layer is also enhanced.

Low-intensity laser coupled with photosensitizer to reduce bacteria in root canals compared to chemical control; Laser em baixa intensidade associado a fotosensibilizador para reducao bacteriana intracanal comparado ao controle quimico

Energy Technology Data Exchange (ETDEWEB)

Garcez Segundo, Aguinaldo Silva

2002-07-01

The photodynamic therapy is a process in which a dye is associate with an appropriate wavelength of light and this dye goes to an excited state. The excited reacts with oxygen to form the highly reactive compound singlet oxygen, and this compound can kill bacteria and tumor cells. The purpose of this study was to evaluate the bactericidal reduction in root canal contaminated with E. Faecalis. Thirty teeth with their root canals prepared were contaminated with E. faecalis. The teeth have received the chemical substance sodium hypochlorite for 30 minutes; ten teeth have received the azulene dye paste for 5 minutes and have been irradiated with a diode laser, output power 10 mW and {lambda}= 685 nm for 3 minutes. Ten teeth have not received treatment (control group). The bacterial reduction was significantly higher for laser group when compared to chemical and control groups. These results indicate photodynamic therapy as an effective method to kill bacteria. (author)

Controllable laser thermal cleavage of sapphire wafers

Science.gov (United States)

Xu, Jiayu; Hu, Hong; Zhuang, Changhui; Ma, Guodong; Han, Junlong; Lei, Yulin

2018-03-01

Laser processing of substrates for light-emitting diodes (LEDs) offers advantages over other processing techniques and is therefore an active research area in both industrial and academic sectors. The processing of sapphire wafers is problematic because sapphire is a hard and brittle material. Semiconductor laser scribing processing suffers certain disadvantages that have yet to be overcome, thereby necessitating further investigation. In this work, a platform for controllable laser thermal cleavage was constructed. A sapphire LED wafer was modeled using the finite element method to simulate the thermal and stress distributions under different conditions. A guide groove cut by laser ablation before the cleavage process was observed to guide the crack extension and avoid deviation. The surface and cross section of sapphire wafers processed using controllable laser thermal cleavage were characterized by scanning electron microscopy and optical microscopy, and their morphology was compared to that of wafers processed using stealth dicing. The differences in luminous efficiency between substrates prepared using these two processing methods are explained.

Spin-controlled ultrafast vertical-cavity surface-emitting lasers

Science.gov (United States)

Höpfner, Henning; Lindemann, Markus; Gerhardt, Nils C.; Hofmann, Martin R.

2014-05-01

Spin-controlled semiconductor lasers are highly attractive spintronic devices providing characteristics superior to their conventional purely charge-based counterparts. In particular, spin-controlled vertical-cavity surface emitting lasers (spin-VCSELs) promise to offer lower thresholds, enhanced emission intensity, spin amplification, full polarization control, chirp control and ultrafast dynamics. Most important, the ability to control and modulate the polarization state of the laser emission with extraordinarily high frequencies is very attractive for many applications like broadband optical communication and ultrafast optical switches. We present a novel concept for ultrafast spin-VCSELs which has the potential to overcome the conventional speed limitation for directly modulated lasers by the relaxation oscillation frequency and to reach modulation frequencies significantly above 100 GHz. The concept is based on the coupled spin-photon dynamics in birefringent micro-cavity lasers. By injecting spin-polarized carriers in the VCSEL, oscillations of the coupled spin-photon system can by induced which lead to oscillations of the polarization state of the laser emission. These oscillations are decoupled from conventional relaxation oscillations of the carrier-photon system and can be much faster than these. Utilizing these polarization oscillations is thus a very promising approach to develop ultrafast spin-VCSELs for high speed optical data communication in the near future. Different aspects of the spin and polarization dynamics, its connection to birefringence and bistability in the cavity, controlled switching of the oscillations, and the limitations of this novel approach will be analysed theoretically and experimentally for spin-polarized VCSELs at room temperature.

The use of laser diodes for control of uranium vaporization rates

International Nuclear Information System (INIS)

Hagans, K.; Galkowski, J.

1993-09-01

Within the Atomic Vapor Laser Isotope Separation (AVLIS) program we have successfully used the laser absorption spectroscopy technique (LAS) to diagnose process physics performance and control vaporization rate. In the LAS technique, a narrow line-width laser is tuned to an absorption line of the species to be measured. The laser light that is propagated through the sample is and, from this data, the density of the species can be calculated. These laser systems have exclusively consisted of expensive, cumbersome, and difficult to maintain argon-ion-pumped ring dye lasers. While the wavelength flexibility of dye lasers is very useful in a laboratory environment, these laser systems are not well suited for the industrial process control system under development for an AVLIS plant. Diode-lasers offer lower system costs, reduced man power requirements, reduced space requirements, higher system availability, and improved operator safety. We report the. successful deployment and test of a prototype laser diode based uranium vapor rate control system. Diode-laser generated LAS data was used to control the uranium vaporization rate in a hands-off mode for greater than 50 hours. With one minor adjustment the system successfully controlled the vaporization rate for greater than 147 hours. We report excellent agreement with ring dye laser diagnostics and uranium weigh-back measurements

A EFICÁCIA DO LASER NA CICATRIZAÇÃO DE ÚLCERA DE DECÚBITO EM PACIENTE DIABÉTICO: ESTUDO DE CASO

Directory of Open Access Journals (Sweden)

Luiz Armando Vidal Ramos

2014-08-01

Full Text Available A úlcera de decúbito tornou-se um dos principais problemas de saúde pública devido o maior tempo de internação em hospitais, alcançando índices preocupantes e mortes evitáveis. Desta forma, o estudo tem como objetivo verificar os efeitos da laserterapia de baixa potência como coadjuvante no tratamento de paciente diabético com úlcera de decúbito. Foi investigada e acompanhada uma paciente diabética do Tipo II portadora de úlcera de decúbito, sendo esta idosa, do gênero feminino, idade 83 anos. Essa paciente foi submetida à aplicação de laser tipo Hélio Neônio (Hene, com comprimento de onda de 670 nm, modo pulsado, método pontual, densidade de energia de 6 J/cm2, com duração de 5 minutos em cada ponto, a qual o procedimento ocorreu durante 5 vezes por semana, no período de 6 semanas. A paciente foi avaliada por meio de registros fotográficos e por mensuração da ferida com uma régua milimétrica, em que delimitou a área da úlcera em cm². Observou-se melhora e redução da úlcera de decúbito a partir da terceira sessão. Com base nos resultados deste estudo o laser tipo Hene foi eficaz no tratamento da úlcera de decúbito em paciente diabético no aspecto cicatrização. Palavras-chave: Laser; Úlcera de Decúbito; Diabetes Mellitus; Cicatrização. DOI: http://dx.doi.org/10.18561/2179-5746/biotaamazonia.v4n2p74-79

Estudo comparativo das extensões das lesões causadas por duas e quatro passadas de laser Erbium em ratos Wistar com 0% de sobreposição dos spots Comparative study of alterations found in 2 and 4 Erbium: YAG laser passes in Wistar rats with 0% overlap of spots

Directory of Open Access Journals (Sweden)

Lúcia de Noronha

2001-06-01

Full Text Available Lasers de CO2 tem sido apresentados com a finalidade de rejuvenecer a face através do resurfacing. Embora cada sistema de laser tenha o mesmo princípio básico, há significativa diferença entre os lasers que pode resultar em variações no efeito tecidual clínico e histológico. O laser Erbium:YAG que tem como característica o comprimento de onda com 10 vezes mais afinidade pela água que o laser de CO2. O propósito deste estudo experimental foi comparar as alterações morfométricas encontradas em 2 e 4 passadas com laser Erbium:YAG com sobreposição de 0% dos spots. Foi avaliada a homogeneidade da ablaçãoem comprimento e usou-se a pele do dorso de 3 ratos in vivo. Foi selecionada uma área de pele controle de cada rato. Finalmente, num período máximo de 3 horas, a pele foi ressecada e encaminhada à histopatologia para as avaliações propostas. Como resultados com 4 passadas houve mais homogeneidade da extensão da ablação do que em 2 passadas. Conclui-se que a extensão e homogeneidade de ablação foi maior com 4 passadas. A utilização de 0% de sobreposição dos spots não garante homogeneidade de ablação.CO2 lasers has been presented with the purpose of rejuvenating the face by means of resurfacing. Though each laser systems has the same base principle, there is a significant difference among lasers which could result in variations in the clinical and histological effects of the tissue. The Erbium:YAG laser has the characteristic of having the wavelength with 10 times more affinity for water than the CO2 laser. The purpose of this experimental study was to compare the morphometric alterations found in 2 and 4 Erbium:YAG laser passes with 0% overlap of spots. It was evaluated the homogeneity of ablation in length and was used the dorsal skin of 3 living mice. It was selected a control area in each mouse. Finally, in the maximum period of three hours, the skin was resected and sent to histopathology for evaluations

Modelagem e controle de cargas em movimento vertical

OpenAIRE

Terceiro, Georges Jean Bruel

2004-01-01

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Engenharia Elétrica Vários são os aspectos envolvidos no processo de controle de movimento de veículos para deslocamento vertical que tornam o seu estudo interessante, sobretudo quando se trata de elevadores para transporte de pessoas, em que pesa sobremaneira o fato da existência de "cargas" vivas e conscientes. O controle do movimento de equipamentos elevadores é realizado a ...

Control system for high power laser drilling workover and completion unit

Science.gov (United States)

Zediker, Mark S; Makki, Siamak; Faircloth, Brian O; DeWitt, Ronald A; Allen, Erik C; Underwood, Lance D

2015-05-12

A control and monitoring system controls and monitors a high power laser system for performing high power laser operations. The control and monitoring system is configured to perform high power laser operation on, and in, remote and difficult to access locations.

Effect of EM Bokashi application on control of secondary soil salinization

Directory of Open Access Journals (Sweden)

Shao Xiaohou

2008-12-01

Full Text Available In order to ameliorate saline-alkaline soil, EM Bokashi has been applied to rice production in conjunction with subdrainage in Ningxia Autonomous Region and Zhejiang Province. The preliminary results can be summarized as follows: EM Bokashi can increase soil organic matter content, improve soil porosity and permeability, and raise the soil's levels of available nutrients; and EM Bokashi combined with subdrainage treatment is more effective in controlling secondary soil salinization and raising the grain yield and quality than other treatments. The results suggest that EM Bokashi can reduce the necessary amount of chemical fertilizer application, thereby improving the agricultural environment, and that the introduction of EM Bokashi into systems of secondary soil salinization control systems has resulted in significant benefits.

Variação da competição interespecífica em milho em função do controle de plantas daninhas em faixas Variation of interspecific weed competition in corn as a function of banded weed control

Directory of Open Access Journals (Sweden)

A. Merotto Jr.

2001-08-01

Full Text Available O controle de plantas daninhas em faixas é mais uma estratégia que pode ser utilizada no manejo integrado de plantas daninhas (MIPD para aumentar a racionalização do uso do ambiente no cultivo de plantas. Os objetivos deste trabalho foram determinar o efeito do controle de plantas daninhas em faixas na linha ou na entrelinha e avaliar suas conseqüências sobre a competição interespecífica na cultura do milho. Os tratamentos constaram do estabelecimento de um gradiente de infestação de Brachiaria plantaginea, obtido com a variação da intensidade do controle em pré-emergência, e do controle de plantas daninhas em pós-emergência realizado em faixas na linha, na entrelinha ou em área total. O controle de plantas daninhas em pós-emergência em faixas não foi suficiente para reduzir os efeitos da competição interespecífica sobre o rendimento de grãos de milho, mesmo em baixas densidades de plantas daninhas. Os prejuízos causados pela presença de plantas daninhas na linha da cultura são duas a três vezes maiores em comparação com a presença destas plantas na entrelinha ou em área total da cultura. O controle de plantas daninhas na linha da cultura necessita de complementação com práticas culturais ou outros métodos de controle destas plantas na entrelinha.Banded weed control is one of the methods used for integrated weed management (IWM to increase the rationalization of environmental use in crop activities management. The aim of this work was to determine the effect of in-and between-row weed control and the effects of weed competition on corn. The treatments consisted in the establishment of a range of Brachiaria plantaginea densities by varying the intensity of weed control in pre-emergence, complemented with post-emergence weed control in-row, between row and broadcast. Banded weed control was not efficient in decreasing weed competition and reducing corn grain yield, even at low weed infestation. In-row weed

Development of the power control system for semiconductor lasers

International Nuclear Information System (INIS)

Kim, Kwang Suk; Kim, Cheol Jung

1997-12-01

For the first year plan of this program, we developed the power control system for semiconductor lasers. We applied the high-current switching mode techniques to fabricating a power control system. Then, we investigated the direct side pumping techniques with GaA1As diode laser bars to laser crystal without pumping optics. We obtained 0.5W average output power from this DPSSL. (author). 54 refs., 3 tabs., 18 figs

Collective ion acceleration via laser controlled ionization channel

International Nuclear Information System (INIS)

Destler, W.W.; O'Shea, P.G.; Rodgers, J.; Segalov, Z.

1987-01-01

Initial results from a successful laser-controlled collective ion acceleration experiment at the University of Maryland are presented. In the experiment, positive ions are trapped in the potential well at the head of an intense relativistic electron beam injected at current levels above the space charge limit. Seed ions for acceleration are provided by puff valve injection of a neutral gas cloud localized to within 3 cm of the injection point. Control over the acceleration of the well and the ions is then achieved by means of a laser-generated ionization channel produced by passing the light from a Q-switched ruby laser through a series of partially and fully reflecting mirrors in such a way as to provide time-sequenced laser ionization of a target located on the drift tube wall. Using this system, controlled acceleration of protons at a rate of approximately 40 MV/m has been demonstrated over a distance of about 50 cm

Eficácia a curto prazo do laser de baixa intensidade em pacientes com osteoartrite do joelho: ensaio clínico aleatório, placebo-controlado e duplo-cego Short-term efficacy of low-level laser therapy in patients with knee osteoarthritis: a randomized placebo-controlled, double-blind clinical trial

Directory of Open Access Journals (Sweden)

Vanessa Ovanessian Fukuda

2011-10-01

Full Text Available OBJETIVO: Este estudo foi designado para avaliar a eficácia a curto prazo da laserterapia de baixa intensidade (LBI na melhora da dor e função em pacientes portadores de osteoartrite (OA do joelho. MÉTODOS: Participaram deste ensaio clínico aleatório, duplo-cego e controlado 47 pacientes (79 joelhos de ambos os sexos portadores de OA do joelho, que foram distribuídos aleatoriamente em dois grupos; grupo laser com 25 pacientes (41 joelhos e grupo placebo com 22 pacientes (38 joelhos. A LBI foi realizada três vezes por semana totalizando nove sessões, com uso do laser AsGa de 904nm, 60mW de potência média e 0,5cm² de área do feixe, sendo irradiados nove pontos no joelho com energia de 3,0J por ponto. O grupo placebo foi tratado com o mesmo aparelho de laser, porém com uma caneta selada. As avaliações Lequesne, escala visual numérica (EVN, Timed Up and Go (TUG, goniometria e dinamometria foram realizadas antes do início do tratamento e após as nove sessões da LBI. RESULTADOS: Foi encontrada melhora significante da dor e função para todas as avaliações aplicadas no grupo laser. Quando comparado o grupo laser ao grupo placebo encontrou-se diferença significante para as avaliações EVN-Repouso e Lequesne. CONCLUSÃO: O tratamento com a LBI melhora a dor e função a curto prazo de pacientes portadores de OA do joelho.OBJECTIVE: This study was designed to evaluate the short-term efficacy of low-level laser therapy (LLLT for improving pain and function in patients with knee osteoarthritis. METHODS: Forty-seven patients with knee osteoarthritis (79 knees, of both genders, participated in this randomized controlled double-blind clinical trial. They were randomly allocated to two groups: laser group with 25 patients (41 knees and placebo group with 22 patients (38 knees. LLLT was performed three times a week, totaling nine sessions, using a AsGa 904 nm laser with mean power of 60 mW and beam area of 0.5 cm². Nine points were

Synchronization control for ultrafast laser parallel microdrilling system

Science.gov (United States)

Zhai, Zhongsheng; Kuang, Zheng; Ouyang, Jinlei; Liu, Dun; Perrie, Walter; Edwardson, Stuart P.; Dearden, Geoff

2014-11-01

Ultrafast lasers, emitting ultra-short pulses of light, generally of the order of femtoseconds to ten picoseconds, are widely used in micro-processing with the advantage of very little thermal damage. Parallel micro-processing is seen significant developments in laser fabrication, thanking to the spatial light modulator (SLM) which can concert single beam to multiple beams through computer generate holograms (CGHs). However, without synchronization control, on the conditions of changing different holograms or processing on large area beyond scanning galvo's ability, the fabrication will be interrupted constantly for changing holograms and moving the stages. Therefore, synchronization control is very important to improve the convenience and application of parallel micro-processing. A synchronization control method, carried out through two application software: SAMLight (or WaveRunner) and Labview, is presented in this paper. SAMLight is used to control the laser and the scanning galvo to implement microprocessing, and the developed program with Labview is used to control the SLM and motion stages. The synchronization signals, transmitted between the two software, are utilized by a National Instruments (NI) device USB-6008. Using optimal control methods, the synchronized system can easily and automatically accomplish complicated fabrications with minimum time. A multi-drilling application is provided to verify the affectivity of the synchronized control method. It uses multiple annular beams, generated by superimposing multi-beam CGH onto a diffractive axicon CGH, to drill multiple holes at one time, and it can automatically finish different patterns based on synchronization control. This drilling way is an optical trepanning and it avoids huge laser energy waste with attenuation. The multi-beam CGHs, generated by the Grating and Lens algorithm, are different for different patterns. The processing is over 200 times faster than traditional mechanical trepanning

O impacto da cirurgia de ceratectomia fotorrefrativa (PRK e ceratomileuse assistida por excimer laser in situ (LASIK na qualidade visual e de vida em pacientes com ametropias The impact of photorefractive excimer laser keratectomy (PRK and laser in situ keratomileusis (LASIK on visual quality and life in patients with ametropias

Directory of Open Access Journals (Sweden)

Ricardo Belfort

2008-02-01

Full Text Available OBJETIVO: Avaliar a qualidade de vida e de visão e o estresse de pacientes portadores de ametropias submetidos a procedimentos cirúrgicos. MÉTODOS: Estudo longitudinal observacional em que foram estudados 100 pacientes; 54 usuários de óculos, 21 usuários de lentes de contato interessados no procedimento cirúrgico e 25 controles usuários de óculos ou lentes de contato, mas que não desejavam ser operados no período de um ano. Os questionários aplicados foram o National Eye Institute Visual Function Questionnaire (NEI-VFQ-25 de qualidade de vida e o Self Reporting Questionnaire - SRQ-20 para avaliação da saúde mental. Os pacientes que se submeteram à cirurgia responderam aos questionários aplicados por uma observadora antes da mesma, três, seis e doze meses após a intervenção. O grupo controle respondeu de forma auto-aplicada no início do estudo, seis e doze meses após a primeira avaliação. RESULTADOS: No grupo da cirugia dos 54 pacientes que usavam óculos 39 fizeram cirurgia de ceratectomia fotorrefrativa por excimer laser(PRK e 15 fizeram ceratomileuse assistida por excimer laserin situ (LASIK e dos 21 que usavam lentes de contato 12 fizeram cirurgia de ceratectomia fotorrefrativa e nove fizeram ceratomileuse assistida por excimer laser in situ (LASIK. O grupo controle esteve estável durante os 12 meses em relação aos instrumentos aplicados. Três meses após a cirurgia o grupo da cirurgia apresentou melhora significante da qualidade de vida e de visão em relação ao pré-operatório independentemente do tipo de cirurgia realizada. Um ano após a cirurgia os índices de qualidade de vida e de saúde mental, foram semelhantes aos do grupo controle. O Self Reporting Questionnaire - SRQ 20 mostrou diminuição significante do índice de sintomas a partir dos três meses de pós-operatório. CONCLUSÃO: A qualidade de visão e de vida dos pacientes submetidos à cirurgia de correção de ametropia mudou

High-resolution wavefront control of high-power laser systems

International Nuclear Information System (INIS)

Brase, J.; Brown, C.; Carrano, C.; Kartz, M.; Olivier, S.; Pennington, D.; Silva, D.

1999-01-01

Nearly every new large-scale laser system application at LLNL has requirements for beam control which exceed the current level of available technology. For applications such as inertial confinement fusion, laser isotope separation, laser machining, and laser the ability to transport significant power to a target while maintaining good beam quality is critical. There are many ways that laser wavefront quality can be degraded. Thermal effects due to the interaction of high-power laser or pump light with the internal optical components or with the ambient gas are common causes of wavefront degradation. For many years, adaptive optics based on thing deformable glass mirrors with piezoelectric or electrostrictive actuators have be used to remove the low-order wavefront errors from high-power laser systems. These adaptive optics systems have successfully improved laser beam quality, but have also generally revealed additional high-spatial-frequency errors, both because the low-order errors have been reduced and because deformable mirrors have often introduced some high-spatial-frequency components due to manufacturing errors. Many current and emerging laser applications fall into the high-resolution category where there is an increased need for the correction of high spatial frequency aberrations which requires correctors with thousands of degrees of freedom. The largest Deformable Mirrors currently available have less than one thousand degrees of freedom at a cost of approximately $1M. A deformable mirror capable of meeting these high spatial resolution requirements would be cost prohibitive. Therefore a new approach using a different wavefront control technology is needed. One new wavefront control approach is the use of liquid-crystal (LC) spatial light modulator (SLM) technology for the controlling the phase of linearly polarized light. Current LC SLM technology provides high-spatial-resolution wavefront control, with hundreds of thousands of degrees of freedom, more

Construção e caracterização de um amplificador em fibra para pulsos ultracurtos em ʎ = 1.5 um

OpenAIRE

ARIAS, Luis Alfredo Giraldo

2014-01-01

Lasers de pulsos ultracurtos baseados em fibras ópticas como meio de ganho constituem fortes candidatos para substituir lasers de estado sólido mais tradicionais, tais como o laser de Ti:safira. Uma das razões é o custo direto e outra é a possibilidade de compactação de sistemas que ocupam muito espaço e consomem quantidades significativas de energia. Um dos problemas de lasers baseados em fibras ópticas é que a potência óptica média disponível é relativamente baixa, da ordem d...

Temperature control in interstitial laser cancer immunotherapy

Science.gov (United States)

Bandyopadhyay, Pradip K.; Holmes, Kyland; Burnett, Corinthius; Zharov, Vladimir P.

2003-07-01

Positive results of Laser-Assisted Cancer Immunotherapy (LACI) have been reported previously in the irradiation of superficial tumors. This paper reports the effect of LACI using laser interstitial therapy approach. We hypothesize that the maximum immuno response depends on laser induced tumor temperature. The measurement of tumor temperature is crucial to ensure necrosis by thermal damage and immuno response. Wister Furth female rats in this study were inoculated with 13762 MAT B III rat mammary adinocarcinoma. LACI started seven to ten days following inoculation. Contrary to surface irradation, we applied laser interstitial irradiation of tumor volume to maximize the energy deposition. A diode laser with a wavelength of 805 nm was used for tumor irradiation. The laser energy was delivered inside the tumor through a quartz fiber. Tumor temperature was measured with a micro thermocouple (interstitial), while the tumor surface temperature was controlled with an IR detector. The temperature feedback demonstrates that it is possible to maintain the average tumor temperature at the same level with reasonable accuracy in the desired range from 65°C-85°C. In some experiments we used microwave thermometry to control average temperature in deep tissue for considerable period of time, to cause maximum thermal damage to the tumor. The experimental set-up and the different temperature measurement techniques are reported in detail, including the advantages and disadvantages for each method.

Optimal control of quantum rings by terahertz laser pulses.

Science.gov (United States)

Räsänen, E; Castro, A; Werschnik, J; Rubio, A; Gross, E K U

2007-04-13

Complete control of single-electron states in a two-dimensional semiconductor quantum-ring model is established, opening a path into coherent laser-driven single-gate qubits. The control scheme is developed in the framework of optimal-control theory for laser pulses of two-component polarization. In terms of pulse lengths and target-state occupations, the scheme is shown to be superior to conventional control methods that exploit Rabi oscillations generated by uniform circularly polarized pulses. Current-carrying states in a quantum ring can be used to manipulate a two-level subsystem at the ring center. Combining our results, we propose a realistic approach to construct a laser-driven single-gate qubit that has switching times in the terahertz regime.

Laser-controlled collective ion accelerator

International Nuclear Information System (INIS)

O'Shea, P.G.; Destler, W.W.; Rodgers, J.; Segalov, Z.

1986-01-01

We report first results from a new collective accelerator experiment in which a laser-controlled channel of ionization is used to control the propagation of the potential well at the front of an intense relativistic electron beam injected at currents above the space-charge limit. The controlled acceleration of protons at the rate of 40 MeV/m over a distance of 45 cm is reported, in good agreement with experimental design values

Regional Suppression of <em>Bactrocera> Fruit Flies (Diptera: Tephritidae in the Pacific through Biological Control and Prospects for Future Introductions into Other Areas of the World

Directory of Open Access Journals (Sweden)

Roger I. Vargas

2012-08-01

Full Text Available <em>Bactrocera> fruit fly species are economically important throughout the Pacific. The USDA, ARS U.S. Pacific Basin Agricultural Research Center has been a world leader in promoting biological control of <em>Bactrocera> spp. that includes classical, augmentative, conservation and IPM approaches. In Hawaii, establishment of <em>Bactrocera> <em>cucurbitae> (Coquillett in 1895 resulted in the introduction of the most successful parasitoid, <em>Psyttalia> <em>fletcheri> (Silvestri; similarly, establishment of <em>Bactrocera> <em>dorsalis> (Hendel in 1945 resulted in the introduction of 32 natural enemies of which <em>Fopius> <em>arisanus> (Sonan, <em>Diachasmimorpha> <em>longicaudata> (Ashmead and <em>Fopius> <em>vandenboschi> (Fullaway were most successful. Hawaii has also been a source of parasitoids for fruit fly control throughout the Pacific region including Australia, Pacific Island Nations, Central and South America, not only for <em>Bactrocera> spp. but also for <em>Ceratitis> and <em>Anastrepha> spp. Most recently, in 2002, <em>F.> <em>arisanus> was introduced into French Polynesia where <em>B.> <em>dorsalis> had invaded in 1996. Establishment of <em>D.> <em>longicaudata> into the new world has been important to augmentative biological control releases against <em>Anastrepha> spp. With the rapid expansion of airline travel and global trade there has been an alarming spread of <em>Bactrocera> spp. into new areas of the world (<em>i.e.>, South America and Africa. Results of studies in Hawaii and French Polynesia, support parasitoid introductions into South America and Africa, where <em>B.> <em>carambolae> and <em>B.> <em>invadens>, respectively, have become established. In addition, <em>P.> <em>fletcheri> is a candidate for biological control of <em>B.> <em>cucurbitae> in Africa. We review past and more

Software para Controle de Temperatura em Estufas

OpenAIRE

Silva, Antonio Carlos Alves; Universidade Federal de Lavras; Kanazawa, Edna Mie; Universidade Federal de Lavras; de Carvalho, Karina Dutra; Universidade Federal de Lavras; Kinoshita, Vanessa Godoy; Universidade Federal de Lavras; Uchoa, Joaquim Quinteiro; Universidade Federal de Lavras; Lacerda, Wilian Soares; Universidade Federal de Lavras; Schneider, Bruno de Oliveira; Universidade Federal de Lavras

2004-01-01

Neste trabalho é apresentado o projeto desenvolvido para controle de temperatura em estufas, denominado CTE, utilizando uma Interface de Aquisição e Controle de Dados. Todo o controle é feito via software, onde pode-se optar por dois tipos de controle: o controle automático, onde é possível definir-se a temperatura mínima e máxima; ou o controle manual, onde o usuário poderá optar por acionar periféricos de aquecimento, resfriamento e desligamento da estufa. Foi desenvolvida também uma interf...

Control of laser pulse waveform in longitudinally excited CO2 laser by adjustment of excitation circuit

Science.gov (United States)

Uno, Kazuyuki; Jitsuno, Takahisa

2018-05-01

In a longitudinally excited CO2 laser that had a 45 cm-long discharge tube with a 1:1:2 mixture of CO2/N2/He gas at a pressure of 3.0 kPa, we realized the generation of a short laser pulse with a spike pulse width of about 200 ns and a pulse tail length of several tens of microseconds, control of the energy ratio of the spike pulse part to the pulse tail part in the short laser pulse, the generation of a long laser pulse with a pulse width of several tens of microseconds, and control of the pulse width in the long laser pulse, by using four types of excitation circuits in which the capacitance was adjusted. In the short laser pulse, the energy ratio was in the range 1:14-1:112. In the long laser pulse, the pulse width was in the range 25.7-82.7 μs.

Hierarchical tree-structured control network for the Antares laser facility

Energy Technology Data Exchange (ETDEWEB)

McGirt, F.

1979-01-01

The design and implementation of a distributed, computer-based control system for the Antares 100-kJ gas laser fusion facility is presented. Control system requirements and their operational interrelationships that consider both integrated system control and individual subsystem control are described. Several configurations of minicomputers are established to provide direct control of sets of microcomputers and to provide points of operator-laser interaction. Over 100 microcomputers are located very close to the laser device control points or sources of data and perform the real-time functions of the control system, such as data and control signal multiplexing, stepping motor control, and vacuum and gas system control. These microcomputers are designed to be supported as an integral part of the control network and to be software compatible with the larger minicomputers.

Hierarchical tree-structured control network for the Antares laser facility

International Nuclear Information System (INIS)

McGirt, F.

1979-01-01

The design and implementation of a distributed, computer-based control system for the Antares 100-kJ gas laser fusion facility is presented. Control system requirements and their operational interrelationships that consider both integrated system control and individual subsystem control are described. Several configurations of minicomputers are established to provide direct control of sets of microcomputers and to provide points of operator-laser interaction. Over 100 microcomputers are located very close to the laser device control points or sources of data and perform the real-time functions of the control system, such as data and control signal multiplexing, stepping motor control, and vacuum and gas system control. These microcomputers are designed to be supported as an integral part of the control network and to be software compatible with the larger minicomputers

Polarization control of multi-photon absorption under intermediate femtosecond laser field

International Nuclear Information System (INIS)

Cheng Wenjing; Liang Guo; Wu Ping; Liu Pei; Jia Tianqing; Sun Zhenrong; Zhang Shian

2017-01-01

It has been shown that the femtosecond laser polarization modulation is a very simple and well-established method to control the multi-photon absorption process by the light–matter interaction. Previous studies mainly focused on the multi-photon absorption control in the weak field. In this paper, we further explore the polarization control behavior of multi-photon absorption process in the intermediate femtosecond laser field. In the weak femtosecond laser field, the second-order perturbation theory can well describe the non-resonant two-photon absorption process. However, the higher order nonlinear effect (e.g., four-photon absorption) can occur in the intermediate femtosecond laser field, and thus it is necessary to establish new theoretical model to describe the multi-photon absorption process, which includes the two-photon and four-photon transitions. Here, we construct a fourth-order perturbation theory to study the polarization control behavior of this multi-photon absorption under the intermediate femtosecond laser field excitation, and our theoretical results show that the two-photon and four-photon excitation pathways can induce a coherent interference, while the coherent interference is constructive or destructive that depends on the femtosecond laser center frequency. Moreover, the two-photon and four-photon transitions have the different polarization control efficiency, and the four-photon absorption can obtain the higher polarization control efficiency. Thus, the polarization control efficiency of the whole excitation process can be increased or decreased by properly designing the femtosecond laser field intensity and laser center frequency. These studies can provide a clear physical picture for understanding and controlling the multi-photon absorption process in the intermediate femtosecond laser field, and also can provide a theoretical guidance for the future experimental realization. (paper)

Analise da adaptação marginal de proteses fixas implanto-suportadas em liga de titanio, fundidas em monobloco ou submetidas a soldagem laser e eletroerosão atraves do assentamento passivo

OpenAIRE

Tatiana Bernardon Peixoto Silva

2001-01-01

Resumo: A proposta deste trabalho foi avaliar o desadaptação marginal de infra-estruturas de próteses fixas implanto-suportadas fundidas em monobloco e submetidas à soldagem laser, antes e após a eletroerosão através da análise do assentaIÍlento passivo. Vinte infta-estruturas foram confeccionadas a partir de um modelo mestre metálico com cinco implantes fixados na região inter-forâmes paralelos entre si, e fundidas em titânio comercialmente puro - Ti c. p. (Rematitan - Dentaurum - Pforzhein ...

Influence of ingaalp laser (660nm on the healing of skin wounds in diabetic rats Influência do laser ingaalp (660nm na cicatrização de feridas cutâneas em ratos diabéticos

Directory of Open Access Journals (Sweden)

Paulo de Tarso Camillo de Carvalho

2010-02-01

Full Text Available PURPOSE: To determine the influence of low-power laser (660 nm on the collagen percentage and macrophages in skin wounds in diabetic rats. METHODS: 30 male Wistar rats were used, distributed in two groups: laser treated diabetic (n= 15; untreated diabetic (n = 15. The diabetes was induced by intravenous injection of alloxan into the dorsal vein of the penis, at a rate of 0.1 ml of solution per 100 g of body weight. A wound was made on the back of all the animals. Groups 2 were treated with Aluminium Gallium Indium Phosphide - InGaAlP type diode laser (Photon Laser III DMC® with a continuous output power of 100 mW and wavelength (? of 660 nm (4 J/cm² for 24 s. five animal from each group was sacrificed on the 3rd, 7th and 14th days after wounding. Samples were taken, embedded in paraffin, stained with hematoxylin-eosin, Masson's trichrome, and immunohistochemical macrophage. morphometrically analyzed using the Image Pro Plus 4.5 software. The percentages of collagen fibers and macrophages were determined from the samples from the euthanasia animals. RESULTS: The data were treated statistically using analysis of variance (ANOVA and the Post-hocTukey test. The significance level was set at 0.05 or 5%. CONCLUSION: The low-power laser (660 nm was shown to be capable of influencing the collagen percentage in skin wounds by increasing the mean quantity of collagen fibers and macrophages.OBJETIVO: Determinar a influência do diodo laser InGaAlP (660 nm sobre o percentual de colágeno e macrófagos em feridas cutâneas de ratos diabéticos. MÉTODOS: Para tanto 30 ratos machos Wistar foram distribuídos em dois grupos: diabético tratado com laser (n=15, diabético não tratado (n = 15. O diabetes foi induzido por injeção intravenosa de aloxana na veia dorsal do pênis, a uma taxa de 0,1 ml de solução por 100 g de peso corporal. A lesão foi confeccionada no dorso de todos os animais utilizando um punch de 8mm. 2 grupos foram tratados com o diodo

Controlling chaotic behavior in CO2 and other lasers

Science.gov (United States)

1993-06-01

Additional substantial experimental progress has been made, in the third month of the project, in setting up equipment and testing for producing chaotic behavior with a CO2 laser. The project goal is to synchronize and control chaos in CO2 and other lasers, and thereby increase the power in ensembles of coupled laser sources. Numerous investigations into the chaos regime have been made, a second CO2 laser has been brought on stream, and work is progressing in the fourth month toward coupling the two lasers and control of the first laser. It is also intended to submit at least two papers to the Second Experimental Chaos Conference which is supported by the Office of Naval Research. Abstracts to those two papers are attached. Last month's report discussed the experimental investigation of nonlinear dynamics of CO2 lasers which involved a new technique of inducing chaos. In this new technique, an acoustically modulated feedback of the laser light was used and led to chaotic dynamics at a very low modulation frequency of 375 Hz. Since then, new results have been obtained by an Electro-Optical Modulation (EOM) technique. In the new setup, the electro-optical modulator is placed in an external cavity outside the laser.

Surface Contaminant Control Technologies to Improve Laser Damage Resistance of Optics

Directory of Open Access Journals (Sweden)

Xiaofeng Cheng

2014-01-01

Full Text Available The large high-power solid lasers, such as the National Ignition Facility (NIF of America and the Shenguang-III (SG-III laser facility of China, can output over 2.1 MJ laser pulse for the inertial confinement fusion (ICF experiments. Because of the enhancement of operating flux and the expansion of laser driver scale, the problem of contamination seriously influences their construction period and operation life. During irradiation by intense laser beams, the contaminants on the metallic surface of beam tubes can be transmitted to the optical surfaces and lead to damage of optical components. For the high-power solid-state laser facilities, contamination control focuses on the slab amplifiers, spatial filters, and final-optical assemblies. In this paper, an effective solution to control contaminations including the whole process of the laser driver is put forward to provide the safe operation of laser facilities, and the detailed technical methods of contamination control such as washing, cleanliness metrology, and cleanliness protecting are also introduced to reduce the probability of laser-induced damage of optics. The experimental results show that the cleanliness level of SG-III laser facility is much better to ensure that the laser facility can safely operate at high energy flux.

Laser de baixa intensidade em deiscência aguda de safenectomia: proposta terapêutica Low level laser therapy in acute dehiscence saphenectomy: therapeutic proposal

Directory of Open Access Journals (Sweden)

Nathali Cordeiro Pinto

2009-03-01

Full Text Available Deiscência é uma complicação temida em cirurgias de grande porte. Paciente submetida a revascularização miocárdica evoluiu com deiscência de safenectomia em membro inferior, edema e dor no 15º dia pós-operatório (PO, tendo sido realizado inicialmente o tratamento convencional no ambulatório sem melhora clínica. No 30º PO, aplicou-se somente Laser de Baixa Intensidade (LBI ao redor da borda da ferida, pontualmente. A lesão respondeu com tecido de granulação, diminuição do processo inflamatório e analgesia desde a primeira aplicação. Neste estudo piloto, a laserterapia mostrou ter um papel importante como agente facilitador de cicatrização, por meio de uma terapia nãoinvasiva, eficaz e segura.Dehiscence is a feared complication after major surgeries. Patient who had undergone coronary artery bypass grafting developed saphenectomy's dehiscence on lower limb with edema and pain on the 15th postoperative day. Conventional treatment had been initially performed without clinical improvement. On the 30th postoperative day only Low Level Laser Therapy (LLLT was applied punctually around surgical wounds edge. The results revealed granulated tissue, reduction of inflammatory process and analgesic effect since the first application. In this pilot study, LLLT has shown a considerable role as a wound healing agent, through a new proposal for efficient, safe and noninvasive therapy.

Laser Soldering of Rat Skin Using a Controlled Feedback System

Directory of Open Access Journals (Sweden)

Mohammad Sadegh Nourbakhsh

2009-03-01

Full Text Available Introduction: Laser tissue soldering using albumin and indocyanine green dye (ICG is an effective technique utilized in various surgical procedures. The purpose of this study was to perform laser soldering of rat skin under a feedback control system and compare the results with those obtained using standard sutures. Material and Methods: Skin incisions were made over eight rats’ dorsa, which were subsequently closed using different wound closure interventions in two groups: (a using a temperature controlled infrared detector or (b by suture. Tensile strengths were measured at 2, 5, 7 and 10 days post-incision. Histological examination was performed at the time of sacrifice. Results: Tensile strength results showed that during the initial days following the incisions, the tensile strengths of the sutured samples were greater than the laser samples. However, 10 days after the incisions, the tensile strengths of the laser soldered incisions were higher than the sutured cuts. Histopathological examination showed a preferred wound healing response in the soldered skin compared with the control samples. The healing indices of the laser soldered repairs (426 were significantly better than the control samples (340.5. Conclusion: Tissue feedback control of temperature and optical changes in laser soldering of skin leads to a higher tensile strength and better histological results and hence this method may be considered as an alternative to standard suturing.

Laser metrology and optic active control system for GAIA

Science.gov (United States)

D'Angelo, F.; Bonino, L.; Cesare, S.; Castorina, G.; Mottini, S.; Bertinetto, F.; Bisi, M.; Canuto, E.; Musso, F.

2017-11-01

The Laser Metrology and Optic Active Control (LM&OAC) program has been carried out under ESA contract with the purpose to design and validate a laser metrology system and an actuation mechanism to monitor and control at microarcsec level the stability of the Basic Angle (angle between the lines of sight of the two telescopes) of GAIA satellite. As part of the program, a breadboard (including some EQM elements) of the laser metrology and control system has been built and submitted to functional, performance and environmental tests. In the followings we describe the mission requirements, the system architecture, the breadboard design, and finally the performed validation tests. Conclusion and appraisals from this experience are also reported.

Control of the droplet generation by an infrared laser

Directory of Open Access Journals (Sweden)

Zhibin Wang

2018-01-01

Full Text Available In this work, the control of the droplet generation by a focused infrared (IR laser with a wavelength of 1550 nm was studied, in which the liquid water and the oil with the surfactant of Span 80 were employed as the disperse and continuous phases, respectively. The characteristics of the droplet generation controlled by the laser was explored under various flow rates, laser powers and spot positions and the comparison between the cases with/without the laser was also performed. The results showed that when the laser was focused on the region away from the outlet of the liquid water inflow channel, the droplet shedding was blocked due to the IR laser heating induced thermocapillary flow, leading to the increase of the droplet volume and the cycle time of the droplet generation as compared to the case without the laser. Decreasing the continuous phase flow rate led to the increase of the droplet volume, cycle time of the droplet generation and the volume increase ratio, while increasing the disperse phase flow rate led to the increase of the droplet volume and the decrease of the cycle time and volume increase ratio. For a given flow rate ratio between the continuous and disperse phases, the increase of the flow rates decreased the volume increase ratio. In addition, it is also found that the droplet volume, the cycle time and the volume increase ratio all increased with the laser power. When the laser was focused at the inlet of the downstream channel, the droplet volume, the cycle time and the volume increase ratio were the largest. Moving the laser spot to the downstream or upstream led to the decrease of them. When the laser was focused on the outlet of the liquid water inflow channel, the generated droplet volume and cycle time of the droplet generation were even lower than the case without the laser because of the lowered viscosity. This works provides a comprehensive understanding of the characteristics of the droplet generation controlled

Effect of diode laser irradiation on the apical sealing of MTA retrofillings Efeito da irradiação de laser de diodo no selamento apical em retrobturações com MTA

Directory of Open Access Journals (Sweden)

Eliana Barbosa de Souza

2006-09-01

Full Text Available Apical sealing is essential for the success of paraendodontic surgery, so any procedure that may favor an adequate sealing of the apical remainder should be performed. The purpose of this study was to evaluate the influence of diode laser irradiation on the apical sealing of root-end cavities with MTA retrofillings. Root canals in twenty extracted human teeth were shaped with K-files and filled with gutta-percha. The apexes were cut off and root-end preparations were performed. The roots were divided randomly in 2 groups. Group 1 (ten specimens was retrofilled with MTA. Group 2 was irradiated with diode laser, with 1 W for 20 seconds, on the apical surface and root end cavity before retrofilling with MTA. The specimens had their external surfaces impermeabilized with cyanoacrylate, except for the apical surface, and were then immersed in 1% rhodamine B dye for 72 h and placed in plaster stone. After that, the specimens were submitted to longitudinal abrasion until half of the root remained. The linear dye leakage was observed in these mid-roots between the root canal wall and retrofilling. The linear dye leakage was measured with Image Lab software, and the results were statistically analyzed with Student's t test. There were no statistically significant differences between the two groups (p > 0.05. The diode laser irradiation did not improve the apical sealing of MTA retrofillings under the conditions of this in vitro study.O selamento apical é fundamental para o sucesso da cirurgia parendodôntica. Assim, procedimentos que melhorem o selamento do remanescente apical devem ser utilizados. O objetivo deste estudo foi verificar se a irradiação de laser de diodo poderia aumentar o selamento apical em cavidades retrógradas obturadas com MTA. Foram utilizadas 20 raízes de dentes humanos extraídos que, após preparo com lima tipo K, tiveram seus canais obturados com guta-percha. Os ápices foram cortados e sofreram preparo de cavidades retr

File list: InP.EmF.50.Input_control.AllCell [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available InP.EmF.50.Input_control.AllCell mm9 Input control Input control Embryonic fibrobla...363,SRX115361 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.EmF.50.Input_control.AllCell.bed ...

File list: InP.EmF.05.Input_control.AllCell [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available InP.EmF.05.Input_control.AllCell mm9 Input control Input control Embryonic fibrobla...367,SRX115361 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.EmF.05.Input_control.AllCell.bed ...

File list: InP.EmF.20.Input_control.AllCell [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available InP.EmF.20.Input_control.AllCell mm9 Input control Input control Embryonic fibrobla...367,SRX115361 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.EmF.20.Input_control.AllCell.bed ...

Perioperative effects of oral midazolam premedication in children undergoing skin laser treatment: a double-blinded randomized placebo-controlled trial Efeitos peroperatórios da premedicação oral de midazolam em crianças submetidas a tratamento de pele por laser: estudo duplo-cego randomizado e controlado

Directory of Open Access Journals (Sweden)

Mehrdad Shoroghi

2011-08-01

Full Text Available PURPOSE: To investigate and compare the efficacy of oral midazolam with two different dosages in orange juice on perioperative hemodynamics and behavioral changes in children who underwent skin laser treatment in an academic educational Hospital. METHODS: Ninety children, candidates for skin laser treatment were randomly assigned to 1 of 3 groups of 30 each: the placebo group received 0.1 ml/kg orange flavored juice, group 2 and 3 receiving 0.5 and 1 mg/kg of injectable midazolam mixed with an equal volume of orange juice, respectively. The main outcome measures included the mask acceptance, patients' behavioral scales and postoperative events. RESULTS: There were no significant differences in heart rate, respiratory rate, and systolic blood pressure among the three groups. However, arterial oxygen saturation was significantly reduced in those given 1 mg.kg-1 midazolam. The median scores of anxiety, separation from parent, preparing an intravenous line, acceptance of the oxygen mask, good sedation, crying reduction and consciousness level were better in midazolam group. Postoperative agitation and re-crying were also more frequent in placebo receivers. Those given 1 mg.kg-1 midazolam were significantly more optimal for sedation, crying, consciousness, preparing an intravenous line, and postoperative re-crying compared with 0.5 mg.kg-1 midazolam receivers. CONCLUSION: As a preanaesthetic medication, the 1 mg.kg-1 dose of orally given midazolam especially in a volume of orange juice and can optimize the children's behavior during skin laser treatment with no serious adverse effects, enhancing their parents' satisfactions about the sedative protocol.OBJETIVO:Investigar e comparar a eficácia do uso oral de midazolam com duas diferentes doses de suco de laranja na hemodinâmica peropeatória e mudanças de desempenho em crianças submetidas tratamento de pele por laser em Hospital educacional e acadêmico. MÉTODOS:Noventa crianças candidatas a

Femtosecond laser control of chemical reaction of carbon monoxide and hydrogen

CSIR Research Space (South Africa)

Du Plessis, A

2010-09-01

Full Text Available Femtosecond laser control of chemical reactions is made possible through the use of pulse-shaping techniques coupled to a learning algorithm feedback loop – teaching the laser pulse to control the chemical reaction. This can result in controllable...

Laser controlled magnetism in hydrogenated fullerene films

International Nuclear Information System (INIS)

Makarova, Tatiana L.; Shelankov, Andrei L.; Kvyatkovskii, Oleg E.; Zakharova, Irina B.; Buga, Sergei G.; Volkov, Aleksandr P.

2011-01-01

Room temperature ferromagnetic-like behavior in fullerene photopolymerized films treated with monatomic hydrogen is reported. The hydrogen treatment controllably varies the paramagnetic spin concentration and laser induced polymerization transforms the paramagnetic phase to a ferromagnetic-like one. Excess laser irradiation destroys magnetic ordering, presumably due to structural changes, which was continuously monitored by Raman spectroscopy. We suggest an interpretation of the data based on first-principles density-functional spin-unrestricted calculations which show that the excess spin from mono-atomic hydrogen is delocalized within the host fullerene and the laser-induced polymerization promotes spin exchange interaction and spin alignment in the polymerized phase.

Laser rangefinders for autonomous intelligent cruise control systems

Science.gov (United States)

Journet, Bernard A.; Bazin, Gaelle

1998-01-01

THe purpose of this paper is to show to what kind of application laser range-finders can be used inside Autonomous Intelligent Cruise Control systems. Even if laser systems present good performances the safety and technical considerations are very restrictive. As the system is used in the outside, the emitted average output power must respect the rather low level of 1A class. Obstacle detection or collision avoidance require a 200 meters range. Moreover bad weather conditions, like rain or fog, ar disastrous. We have conducted measurements on laser rangefinder using different targets and at different distances. We can infer that except for cooperative targets low power laser rangefinder are not powerful enough for long distance measurement. Radars, like 77 GHz systems, are better adapted to such cases. But in case of short distances measurement, range around 10 meters, with a minimum distance around twenty centimeters, laser rangefinders are really useful with good resolution and rather low cost. Applications can have the following of white lines on the road, the target being easily cooperative, detection of vehicles in the vicinity, that means car convoy traffic control or parking assistance, the target surface being indifferent at short distances.

Integrated Laser Characterization, Data Acquisition, and Command and Control Test System

Science.gov (United States)

Stysley, Paul; Coyle, Barry; Lyness, Eric

2012-01-01

Satellite-based laser technology has been developed for topographical measurements of the Earth and of other planets. Lasers for such missions must be highly efficient and stable over long periods in the temperature variations of orbit. In this innovation, LabVIEW is used on an Apple Macintosh to acquire and analyze images of the laser beam as it exits the laser cavity to evaluate the laser s performance over time, and to monitor and control the environmental conditions under which the laser is tested. One computer attached to multiple cameras and instruments running LabVIEW-based software replaces a conglomeration of computers and software packages, saving hours in maintenance and data analysis, and making very longterm tests possible. This all-in-one system was written primarily using LabVIEW for Mac OS X, which allows the combining of data from multiple RS-232, USB, and Ethernet instruments for comprehensive laser analysis and control. The system acquires data from CCDs (charge coupled devices), power meters, thermistors, and oscilloscopes over a controllable period of time. This data is saved to an html file that can be accessed later from a variety of data analysis programs. Also, through the LabVIEW interface, engineers can easily control laser input parameters such as current, pulse width, chiller temperature, and repetition rates. All of these parameters can be adapted and cycled over a period of time.

Test of remote control cutting equipment by Nd:YAG laser

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Akio [Fuji Electric Corp. Research and Development Ltd., Yokosuka, Kanagawa (Japan); Hosoda, Hiroshi

1997-11-01

Technology of remote controlled cutting and reduction of generative secondary products have been required to the cutting system for decommissioning nuclear equipments. At a point of view that laser cutting technology by use of a Nd:YAG laser is effective, we have developed the laser cutting machine and carried out cutting tests for several stainless steel plates. This report is described the result of experiment by test equipment, about element technology of remote controlled cutting nuclear equipments. (author)

Test of remote control cutting equipment by Nd:YAG laser

International Nuclear Information System (INIS)

Shimizu, Akio; Hosoda, Hiroshi.

1997-01-01

Technology of remote controlled cutting and reduction of generative secondary products have been required to the cutting system for decommissioning nuclear equipments. At a point of view that laser cutting technology by use of a Nd:YAG laser is effective, we have developed the laser cutting machine and carried out cutting tests for several stainless steel plates. This report is described the result of experiment by test equipment, about element technology of remote controlled cutting nuclear equipments. (author)

Eficiência de fungicidas no controle da brusone em trigo

Directory of Open Access Journals (Sweden)

João Romero do Amaral Santos de Carvalho Rocha

2014-12-01

Full Text Available Causada pelo fungo Pyricularia grisea, a brusone do trigo constitui-se num dos principais entraves à expansão da produção tritícola no Brasil Central. O objetivo deste trabalho foi avaliar a eficiência de fungicidas no controle da brusone em trigo. Foram utilizados três fungicidas, com princípios ativos distintos, combinados com quatro genótipos de trigo. Realizaram-se duas aplicações do produto comercial, sendo estas no estádio 45 e 65 da escala de Zadokset al. A inoculação artificial com os esporos de P. grisea ocorreu no estádio 58-60 da referida escala. Determinou-se a área abaixo da curva de progresso da doença (AACPD, a severidade em folhas bandeira (SEVFB e em espigas (SEVEsp e quantificou-se a produção de grãos (PG.Ao final do trabalho, os diferentes parâmetros analisados foram submetidos à análise de correlação de Pearson.Os fungicidas epoxiconazol+piraclostrobina e tebuconazol+trifloxistrobina foram os que proporcionaram menor AACPD nos genótipos VI 03061, VI 07505 e BRS 254. Não houve diferença para SEVFB entre os genótipos na presença de fungicidas. As linhagens VI 98053 e VI 07505 apresentam menor SEVFB na ausência de fungicidas.O fungicida tebuconazole+trifloxistrobina proporcionou maior PG e menor SEVEsp. A severidade da doença em espigas foi maior do que em folhas bandeira. O controle da brusoneem trigo através da aplicação de fungicidas mostrou-se eficiente em folhas bandeira, mas não eficiente para o controle nas espigas.

Application of laser chaos control methods to controlling thyroid-catatonic oscillations and burst firing of dopamine neurons

Science.gov (United States)

Duong-van, Minh

1993-11-01

A method of controlling chaotic to laminar flows in the Lorenz equations using fixed points dictated by minimizing the Lyapunov functional was proposed by Singer, Wang and Bau. Using different fixed points, we find that the solutions in a chaotic regime can also be periodic. Since the lasers equations are isomorphic to the Lorenz equations, we use this new method to control chaos when the laser is operated over the pump threshold. Furthermore, by solving the laser equations with an occasional proportional feedback mechanism, we recover the essential lasers controlling features experimentally discovered by Roy, Murphy, Jr., Maier, Gills and Hunt. This method of control chaos is now extended to various medical and biological systems.

Control system for JAERI Free Electron Laser

International Nuclear Information System (INIS)

Sugimoto, Masayoshi

1992-01-01

A control system comprising of the personal computers network and the CAMAC stations for the JAERI Free Electron Laser is designed and is in the development stage. It controls the equipment and analyzes the electron and optical beam experiments. The concept and the prototype of the control system are described. (author)

Breakdown plasma and vortex flow control for laser ignition using a combination of nano- and femto-second lasers.

Science.gov (United States)

Kojima, Hirokazu; Takahashi, Eiichi; Furutani, Hirohide

2014-01-13

The breakdown plasma and successive flow leading to combustion are controlled by the combination of a nano-second Nd:YAG laser and a femto-second Ti:Sapphire (TiS) laser. The behaviors are captured by an intensified charged coupled device (ICCD) camera and a high-speed schlieren optical system. The TiS laser determines the initial position of the breakdown by supplying the initial electrons in the optical axis of focusing YAG laser pulses. We show that the initial position of the breakdown can be controlled by the incident position of the TiS laser. In addition, the ignition lean limit of the flammable mixture changes depending on the TiS laser incident position, which is influenced by hot gas distribution and the flow in the flame kernel.

Distributed Bragg grating frequency control in metallic nano lasers

NARCIS (Netherlands)

Marell, M.J.H.; Hill, M.T.

2010-01-01

We show that Bragg gratings can be readily incorporated into metallic nano-lasers which exploit waveguides with semiconductor cores, via modulation of the waveguide width. This provides a simple way to implement laser wavelength control.

Control over phase separation and nucleation using a laser-tweezing potential

Science.gov (United States)

Walton, Finlay; Wynne, Klaas

2018-05-01

Control over the nucleation of new phases is highly desirable but elusive. Even though there is a long history of crystallization engineering by varying physicochemical parameters, controlling which polymorph crystallizes or whether a molecule crystallizes or forms an amorphous precipitate is still a poorly understood practice. Although there are now numerous examples of control using laser-induced nucleation, the absence of physical understanding is preventing progress. Here we show that the proximity of a liquid-liquid critical point or the corresponding binodal line can be used by a laser-tweezing potential to induce concentration gradients. A simple theoretical model shows that the stored electromagnetic energy of the laser beam produces a free-energy potential that forces phase separation or triggers the nucleation of a new phase. Experiments in a liquid mixture using a low-power laser diode confirm the effect. Phase separation and nucleation using a laser-tweezing potential explains the physics behind non-photochemical laser-induced nucleation and suggests new ways of manipulating matter.

Some safety considerations in laser-controlled thermonuclear reactors. Final report

International Nuclear Information System (INIS)

Botts, T.E.; Breton, D.; Chan, C.K.; Levy, S.I.; Sehnert, M.; Ullman, A.Z.

1978-07-01

A major objective of this study was to identify potential safety questions for laser controlled thermonuclear reactors. From the safety viewpoint, it does not appear that the actual laser controlled thermonuclear reactor conceptual designs present hazards very different than those of magnetically confined fusion reactors. Some aspects seem beneficial, such as small lithium inventories, and the absence of cryogenic devices, while other aspects are new, for example the explosion of pressure vessels and laser hazards themselves. Major aspects considered in this report include: (a) general safety considerations, (b) tritium inventories, (c) system behavior during loss of flow accidents, and (d) safety considerations of laser related penetrations

Análise da dose do laser de baixa potência em equipamentos nacionais Analysis of low-level laser therapy doses in Brazilian equipment

Directory of Open Access Journals (Sweden)

TY Fukuda

2008-02-01

Full Text Available CONTEXTUALIZAÇÃO: A laserterapia de baixa potência vem sendo cada vez mais utilizada, e o crescente interesse por seus efeitos relaciona-se com a grande quantidade de publicações científicas. Muitos terapeutas e pesquisadores têm-se baseado na definição da dose do laser pela densidade energética (deltaE; porém, a grande variedade de equipamentos de laser pode levar a diferença nos resultados terapêuticos encontrados, por fornecerem parâmetros que variam de acordo com o fabricante. OBJETIVO: Analisar a energia final transmitida ao tecido ao aplicar-se a mesma deltaE em equipamentos de diferentes marcas nacionais. MATERIAIS E MÉTODOS: Foram avaliados sete equipamentos nacionais, com potência média (Pm diferentes, e foram realizadas simulações aplicando deltaE de 1J/cm² em cada aparelho, para avaliar possíveis diferenças na energia final. RESULTADOS: A mesmadeltaE aplicada em diferentes aparelhos nacionais forneceu energia final que variou entre 10 e 90mJ. Esta variação na energia deveu-se principalmente a diferenças na Pm, sendo encontrados valores entre 5,4 e 75mW. CONCLUSÃO: Esta variabilidade na energia final, que é transmitida ao tecido, indica que a deltaE parece não ser o parâmetro que melhor descreve a dose a ser utilizada. É preciso mencionar não só a deltaE, mas também a energia final, para que se possa estabelecer a dose para obtenção do melhor resultado terapêutico.INTRODUCTION: Low-level laser therapy is becoming more popular and there is a growing interest in its effects, as reflected in the increased number of articles published about the subject. Many therapists and researchers have used a laser dose definition based on energy density (deltaE. However, the variety of laser equipments may lead to differences in the therapeutic results found, since the parameters supplied by these equipments vary according to the manufacturer. OBJECTIVE: To analyze the final energy transmitted to the tissue when

Biomedical effects of low-power laser controlled by electroacupuncture

Science.gov (United States)

Kalenchits, Nadezhda I.; Nicolaenko, Andrej A.; Shpilevoj, Boris N.

1997-12-01

The methods and technical facilities of testing the biomedical effects caused by the influence of low-power laser radiation in the process of laser therapy are presented. Described studies have been conducted by means of the complex of fireware facilities consisting of the system of electroacupuncture diagnostics (EA) and a system of laser therapy on the basis of multichannel laser and magneto-laser devices. The task of laser therapy was concluded in undertaking acupuncture anaesthetization, achievement of antioedemic and dispersional actions, raising tone of musculus and nervous system, normalization of immunity factors under the control of system EA. The 82 percent to 95 percent agreement of the result of an electroacupuncture diagnostics with clinical diagnoses were achieved.

Correlation control theory of chaotic laser systems

International Nuclear Information System (INIS)

Li Fuli.

1986-04-01

A novel control theory of chaotic systems is studied. The correlation functions are calculated and used as feedback signals of the chaotic lasers. Computer experiments have shown that in this way the chaotic systems can be controlled to have time-independent output when the external control parameters are in chaotic domain. (author)

Pain control in small animalsControle da dor em pequenos animais

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Julia Duarte Penter

2011-12-01

Full Text Available Pain is an unpleasant sensory or emotional experience that follows the application of a noxious stimulus. Can be experienced with or without the concomitant occurrence of physical stress signs, which occurs frequently in animals caused by trauma, systemic disease or surgical procedures. The control depends on length, where there are painful impulses and mental status of the animal. It is an important clinical condition, resulting in suffer that will affect quality life. This paper is a review of pathophysiology and pain control in small animals.A dor é uma experiência sensorial ou emocional desagradável que se segue à aplicação de um estímulo nocivo. Pode ser vivenciada com ou sem o acontecimento concomitante de sinais físicos de estresse, trauma, doença sistêmica ou procedimento cirúrgico. Seu controle depende de sua duração, de onde surgem os impulsos dolorosos e do estado de consciência do animal. É uma condição clinicamente importante, que resulta em sofrimento e afeta a qualidade de vida dos animais. O objetivo deste trabalho é a revisão da fisiopatologia e controle da dor em pequenos animais.

Ultrafast laser based coherent control methods for explosives detection

Energy Technology Data Exchange (ETDEWEB)

Moore, David Steven [Los Alamos National Laboratory

2010-12-06

The detection of explosives is a notoriously difficult problem, especially at stand-off, due to their (generally) low vapor pressure, environmental and matrix interferences, and packaging. We are exploring Optimal Dynamic Detection of Explosives (ODD-Ex), which exploits the best capabilities of recent advances in laser technology and recent discoveries in optimal shaping of laser pulses for control of molecular processes to significantly enhance the standoff detection of explosives. The core of the ODD-Ex technique is the introduction of optimally shaped laser pulses to simultaneously enhance sensitivity to explosives signatures while dramatically improving specificity, particularly against matrix materials and background interferences. These goals are being addressed by operating in an optimal non-linear fashion, typically with a single shaped laser pulse inherently containing within it coherently locked control and probe subpulses. Recent results will be presented.

Frequency stabilization of a He-Ne gas laser by controlling refractive index of laser plasma

International Nuclear Information System (INIS)

Xie Yi; Wu Yizun

1991-01-01

A new way to stabilize the frequency of a Zeeman He-Ne gas laser is described. The laser frequency is stabilized by controlling the refractive index of the laser plasma. It does not need a gas laser tube with a piezoelectric ceramic (PZT) made by special technology. As the phase-locking technology is used in the laser servo system, the self-beat frequency is a constant and the frequency stability is better than 2.2 x 10 -11 (averaging time = 10 sec.). The long term frequency fluctuation never exceeded 2 x 10 -8 during two months. The frequency of the locked point can be adjusted continuously in the range of over 200 MHz

EFICÁCIA CLÍNICA DO LASER ACUPUNTURAL NO TRATAMENTO DA DESORDEM TEMPOROMANDIBULAR

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Diego Rodrigues Pessoa

2016-12-01

Full Text Available A disfunção temporomandibular (DTM é a condição mais frequente de dor orofacial crônica. A DTM é caracterizada pela a presença de sinais e sintomas na região orofacial. A acupuntura e Terapia a laser de baixa intensidade (TLBI vêm sendo empregadas no tratamento da DTM. A acupuntura consiste na inserção de agulhas em acupontos específicos do corpo para promover efeitos terapêuticos. A TLBI é uma modalidade de tratamento não invasiva, que vem sendo utilizada com frequência na prática clínica para o tratamento das DTM. Diante do exposto, o objetivo deste estudo foi realizar revisão de literatura, acerca da eficácia clinica do laser acupuntural em pacientes com a DTM. O emprego do laseracupuntural no tratamento das DTM favorece o controle antálgico, miorrelaxante e anti-inflamatório, no entanto, são necessárias novas pesquisas acerca do tema para determinar a eficácia do laser acupuntural em longo prazo para o tratamento de desordens temporomandibulares.

Small laser spot versus standard laser spot photodynamic therapy for idiopathic choroidal neovascularization: a randomized controlled study.

Science.gov (United States)

Li, Xiao-xin; Tao, Yong

2012-12-01

Idiopathic choroidal neovascularization (ICNV) affects young patients and thus may have a significant impact on vision and life quality over a patient's lifespan. This study was designed to compare the visual outcome and retinal pigment epithelium (RPE) damage after photodynamic therapy (PDT) with small laser spot and PDT with standard laser spot for idiopathic choroidal neovascularization (ICNV). This was a randomized controlled study. Fifty-two patients with ICNV were enrolled and randomly divided into a study group (small laser spot PDT, n = 27) and a control group (standard laser spot PDT, n = 25). Best corrected visual acuity (BCVA), optic coherence tomography (OCT) and fluorescein angiography (FA) findings were the main measurements. The patients were followed up 1 week, 1, 3, 6, 9 months and 1 year after PDT. BCVA improvement was statistically significantly higher in the study group than the control group at 6-month ((25.53 ± 15.01) letters vs. (14.71 ± 11.66) letters, P = 0.025) and 9-month follow-ups ((27.53 ± 17.78) letters vs. (15.59 ± 12.21) letters, P = 0.039). At 3- and 6-month follow-ups, the quadrants of RPE damage between the two groups varied significantly (P laser spot PDT group than in the standard laser spot PDT group for ICNV.

Method of laser beam coding for control systems

Science.gov (United States)

Pałys, Tomasz; Arciuch, Artur; Walczak, Andrzej; Murawski, Krzysztof

2017-08-01

The article presents the method of encoding a laser beam for control systems. The experiments were performed using a red laser emitting source with a wavelength of λ = 650 nm and a power of P ≍ 3 mW. The aim of the study was to develop methods of modulation and demodulation of the laser beam. Results of research, in which we determined the effect of selected camera parameters, such as image resolution, number of frames per second on the result of demodulation of optical signal, is also shown in the paper. The experiments showed that the adopted coding method provides sufficient information encoded in a single laser beam (36 codes with the effectiveness of decoding at 99.9%).

Control and EMS of a Grid-Connected Microgrid with Economical Analysis

Directory of Open Access Journals (Sweden)

Mohamed El-Hendawi

2018-01-01

Full Text Available Recently, significant development has occurred in the field of microgrid and renewable energy systems (RESs. Integrating microgrids and renewable energy sources facilitates a sustainable energy future. This paper proposes a control algorithm and an optimal energy management system (EMS for a grid-connected microgrid to minimize its operating cost. The microgrid includes photovoltaic (PV, wind turbine (WT, and energy storage systems (ESS. The interior search algorithm (ISA optimization technique determines the optimal hour-by-hour scheduling for the microgrid system, while it meets the required load demand based on 24-h ahead forecast data. The control system consists of three stages: EMS, supervisory control and local control. EMS is responsible for providing the control system with the optimum day-ahead scheduling power flow between the microgrid (MG sources, batteries, loads and the main grid based on an economic analysis. The supervisory control stage is responsible for compensating the mismatch between the scheduled power and the real microgrid power. In addition, this paper presents the local control design to regulate the local power, current and DC voltage of the microgrid. For verification, the proposed model was applied on a real case study in Oshawa (Ontario, Canada with various load conditions.

Control of proton beam divergence in intense-laser foil-plasma interaction

International Nuclear Information System (INIS)

Kawata, S.; Sonobe, R.; Miyazaki, S.; Sakai, K.; Kikuchi, T.

2006-01-01

Quality of an ion beam is one of the critical factors in intense-laser ion beam generation. A purpose of this study is the suppression of transverse proton divergence by a controlled electron cloud in laser-foil interactions. In this study, the foil target has a hole at the opposite side of the laser illumination. The electrons accelerated by an intense laser are limited in transverse by a neutral plasma at a protuberant part. Therefore the protons are accelerated and also controlled transversely by the electron cloud structure. In our 2.5-dimensional Particle-in-Cell simulations we demonstrate that the transverse shape of the electron cloud is well controlled and the collimated proton beam is generated successfully in the target with the hole. (authors)

Controlling Laser Spot Size in Outer Space

Science.gov (United States)

Bennett, Harold E.

2005-01-01

Three documents discuss a method of controlling the diameter of a laser beam projected from Earth to any altitude ranging from low orbit around the Earth to geosynchronous orbit. Such laser beams are under consideration as means of supplying power to orbiting spacecraft at levels of the order of tens of kilowatts apiece. Each such beam would be projected by use of a special purpose telescope having an aperture diameter of 15 m or more. Expanding the laser beam to such a large diameter at low altitude would prevent air breakdown and render the laser beam eyesafe. Typically, the telescope would include an adaptive-optics concave primary mirror and a convex secondary mirror. The laser beam transmitted out to the satellite would remain in the near field on the telescope side of the beam waist, so that the telescope focal point would remain effective in controlling the beam width. By use of positioning stages having submicron resolution and repeatability, the relative positions of the primary and secondary mirrors would be adjusted to change the nominal telescope object and image distances to obtain the desired beam diameter (typically about 6 m) at the altitude of the satellite. The limiting distance D(sub L) at which a constant beam diameter can be maintained is determined by the focal range of the telescope 4 lambda f(sup 2) where lambda is the wavelength and f the f/number of the primary mirror. The shorter the wavelength and the faster the mirror, the longer D(sub L) becomes.

NÍVEL DE CONTROLE DE Diloboderus abderus EM AVEIA PRETA, LINHO, MILHO E GIRASSOL

Directory of Open Access Journals (Sweden)

Silva Mauro Tadeu Braga da

2002-01-01

Full Text Available O estudo aqui relatado foi conduzido nas safras agrícolas de 1991 e 1992, em Cruz Alta, no Rio Grande do Sul. O objetivo foi avaliar o efeito de diferentes níveis de infestação de Diloboderus abderus Sturm, 1826 (Coleoptera: Melolonthidae em aveia preta (Avena strigosa L., em linho (Linum usitatissimum L., em milho (Zea mays L. e em girassol (Helianthus annuus L., no sistema de plantio direto. O aumento do número de larvas/m² propiciou a ocorrência de danos e, em conseqüência, a diminuição da população de plantas, da massa seca da parte aérea e da produtividade. Os níveis de controle obtidos foram variáveis dependendo da cultura. Com base nos danos produzidos pelo inseto, sugerem-se os níveis de controle de 12 larvas/m² em linho, de 10 larvas/m² em aveia preta, de 0,5 larva/m² em milho e de 0,4 larva/m² em girassol, como indicador para tratamento de sementes destas culturas com inseticidas.

Cicatrização da membrana timpânica na timpanocentese com laser de argônio comparado à técnica com microlanceta: estudo experimental em ratos Tympanic membrane healing in myringotomies performed with argon laser or microknife: an experimental study in rats

Directory of Open Access Journals (Sweden)

Lucio Almeida Castagno

2006-12-01

Full Text Available Otite média secretora (OMS e otite média aguda recorrente (OMAR podem necessitar tratamento cirúrgico para adequada ventilação da orelha média. A abertura clássica do tímpano (timpanocentese requer incisão por microlanceta sob controle de microscópio cirúrgico e mantém-se patente por alguns dias. Estudos recentes sugerem que a timpanocentese feita por diferentes lasers pode permanecer permeável por maior tempo, o que possibilitaria a normalização da otite média. MATERIAL E MÉTODOS: Neste estudo experimental 34 ratos linhagem Wistar, albinos, machos adultos pesando cerca de 300g, foram anestesiados com cetamina 27 mg/kg e xilazina 2,7 mg/kg. A seguir, foram submetidos à timpanocentese incisional com microlanceta no ouvido direito (ML-OD, e à timpanocentese mediada por laser de argônio no ouvido esquerdo (LA-OE. RESULTADOS: Não houve diferença significativa no tempo de cicatrização das timpanocenteses feitas com laser de argônio ou microlanceta. Todas as timpanocenteses cicatrizaram em 10 dias. CONCLUSÃO: A timpanocentese com laser de argônio apresentou patência e cicatrização semelhantes à técnica clássica com microlanceta realizada em ratos Wistar sem enfermidades de orelha média.Secretory otitis media (SOM and recurrent acute otitis media (RAOM may require surgical treatment to proper ventilate the middle ear. Incisional myringotomy is usually done under microscopy with a micro-knife , but it remains patent for just a few days. Recent research indicates that laser assisted myringotomies remain open much longer, allowing middle ear ventilation and healing. MATERIAL AND METHODS: In this experimental study 34 white, male, adult, Wistar rats, without middle ear disease were submited to anesthesia with ketamine 27 mg/kg and xylazine 2,7 mg/kg. Incisional myringotomy was done on the right ear, while laser myringotomy was done on the left. Myringotomies were evaluated periodically until healing. RESULTS: The healing

An injection seeded single frequency Nd:YAG Q-switched laser with precisely controllable laser pulse firing time

Science.gov (United States)

Wu, Frank F.; Khizhnyak, Anatoliy; Markov, Vladimir

2010-02-01

We have realized a single frequency Q-switched Nd:YAG laser with precisely controllable lasing time and thus enabled synchronization of multi-laser systems. The use of injection seeding to the slave ring oscillator results in unidirectional Q-switched laser oscillation with suppression of bidirectional Q-switched oscillation that otherwise would be initiated from spontaneous emission if the seeding laser is not present. Under normal condition, the cavity is high in loss during the pumping period; then a Pockels cell opens the cavity to form the pulse build up, with a second Pockels cell to perform cavity dumping, generating the Q-switched pulse output with optimized characteristics. The two Pockels cells can be replaced by a single unit if an adjustable gated electrical pulse is applied to the Pockels cell in which the pulse front is used to open the cavity and the falling edge to dump the laser pulse. Proper selection of the pump parameters and Pockels-cell gating enables operation of the system in a mode in which the Q-switched pulse can be formed only under the seeding condition. The advantage of the realized regime is in stable laser operation with no need in adjustment of the seeded light wavelength and the mode of the cavity. It is found that the frequency of the Q-switched laser radiation matches well to the injected seeded laser mode. By using two-stage amplifiers, an output energy better than 300 mJ has been achieved in MOPA configuration without active control of the cavity length and with pulse width adjustability from several nanoseconds to 20 ns. The Q-switched oscillator operates not only at precisely controlled firing time but also can be tuned over wide range. This will enable multi-laser systems synchronization and frequency locking down each other if necessary.

Computer controlling of writing beam in laser microfabrication of diffractive optics

OpenAIRE

Korolkov, V.; Shimansky, R.; Cherkashin, V.; Denk, D.

2003-01-01

Laser microfabrication of diffractive optics with continuous relief is based on the direct local action of focused laser radiation on the recording material. Control of writing beam parameters (beam power, spot size, waist position) is one of the main tasks in microfabrication using laser writing systems. Method of the control defines the correspondence between the fabricated microrelief of the diffractive optical element and a designed one. Complexity of this task consists in the necessity t...

Controlled modification of biomolecules by ultrashort laser pulses in polar liquids

DEFF Research Database (Denmark)

Gruzdev, Vitaly; Korkin, Dmitry; Mooney, Brian P.

2017-01-01

Targeted chemical modification of peptides and proteins by laser pulses in a biologically relevant environment, i.e. aqueous solvent at room temperature, allows for accurate control of biological processes. However, the traditional laser methods of control of chemical reactions are applicable onl...

A Tunable Mid-Infrared Solid-State Laser with a Compact Thermal Control System

Directory of Open Access Journals (Sweden)

Deyang Yu

2018-05-01

Full Text Available Tunable mid-infrared lasers are widely used in laser spectroscopy, gas sensing and many other related areas. In order to solve heat dissipation problems and improve the environmental temperature adaptability of solid-state laser sources, a tunable all-fiber laser pumped optical parametric oscillator (OPO was established, and a compact thermal control system based on thermoelectric coolers, an automatic temperature control circuit, cooling fins, fans and heat pipes was integrated and designed for the laser. This system is compact, light and air-cooling which satisfies the demand for miniaturization of lasers. A mathematical model and method was established to estimate the cooling capacity of this thermal control system under different ambient environments. A finite-element model was built and simulated to analyze the thermal transfer process. Experiments in room and high temperature environments were carried out and showed that the substrate temperature of a pump module could be maintained at a stable value with controlled precision to 0.2 degrees, while the output power stability of the laser was within ±1%. The experimental results indicate that this compact air-cooling thermal control system could effectively solve the heat dissipation problem of mid-infrared solid-state lasers with a one hundred watts level pump module in room and high temperature environments.

Intensity and frequency stabilization of a laser diode by simultaneously controlling its temperature and current

Science.gov (United States)

Mu, Weiwei; Hu, Zhaohui; Wang, Jing; Zhou, Binquan

2017-10-01

Nuclear magnetic resonance gyroscope (NMRG) detects the angular velocity of the vehicle utilizing the interaction between the laser beam and the alkali metal atoms along with the noble gas atoms in the alkali vapor cell. In order to reach high precision inertial measurement target, semiconductor laser in NMRG should have good intensity and frequency stability. Generally, laser intensity and frequency are stabilized separately. In this paper, a new method to stabilize laser intensity and frequency simultaneously with double-loop feedback control is presented. Laser intensity is stabilized to the setpoint value by feedback control of laser diode's temperature. Laser frequency is stabilized to the Doppler absorption peak by feedback control of laser diode's current. The feedback control of current is a quick loop, hence the laser frequency stabilize quickly. The feedback control of temperature is a slow loop, hence the laser intensity stabilize slowly. With the feedback control of current and temperature, the laser intensity and frequency are stabilized finally. Additionally, the dependence of laser intensity and frequency on laser diode's current and temperature are analyzed, which contributes to choose suitable operating range for the laser diode. The advantage of our method is that the alkali vapor cell used for stabilizing laser frequency is the same one as the cell used for NMRG to operate, which helps to miniaturize the size of NMRG prototype. In an 8-hour continuous measurement, the long-term stability of laser intensity and frequency increased by two orders of magnitude and one order of magnitude respectively.

Laboratory transferability of optimally shaped laser pulses for quantum control

International Nuclear Information System (INIS)

Moore Tibbetts, Katharine; Xing, Xi; Rabitz, Herschel

2014-01-01

Optimal control experiments can readily identify effective shaped laser pulses, or “photonic reagents,” that achieve a wide variety of objectives. An important additional practical desire is for photonic reagent prescriptions to produce good, if not optimal, objective yields when transferred to a different system or laboratory. Building on general experience in chemistry, the hope is that transferred photonic reagent prescriptions may remain functional even though all features of a shaped pulse profile at the sample typically cannot be reproduced exactly. As a specific example, we assess the potential for transferring optimal photonic reagents for the objective of optimizing a ratio of photoproduct ions from a family of halomethanes through three related experiments. First, applying the same set of photonic reagents with systematically varying second- and third-order chirp on both laser systems generated similar shapes of the associated control landscape (i.e., relation between the objective yield and the variables describing the photonic reagents). Second, optimal photonic reagents obtained from the first laser system were found to still produce near optimal yields on the second laser system. Third, transferring a collection of photonic reagents optimized on the first laser system to the second laser system reproduced systematic trends in photoproduct yields upon interaction with the homologous chemical family. These three transfers of photonic reagents are demonstrated to be successful upon paying reasonable attention to overall laser system characteristics. The ability to transfer photonic reagents from one laser system to another is analogous to well-established utilitarian operating procedures with traditional chemical reagents. The practical implications of the present results for experimental quantum control are discussed

Efeitos da radiação laser de dióxido de carbono em tecido ósseo: estudo macroscópico em ratos Effect of carbon dioxide laser radiation on osseous tissue: macroscopic study in rats

Directory of Open Access Journals (Sweden)

Walter NICCOLI-FILHO

2001-06-01

Full Text Available O laser de dióxido de carbono (CO2, pelas suas propriedades intrínsecas, tem se tornado um instrumento cirúrgico importante; entre estas podemos citar: hemostasia, redução do edema e da dor pós-operatória e esterilização do campo cirúrgico. Seu uso em tecido ósseo para realização de osteotomias ainda é questionável, principalmente devido à possibilidade de iatrogenias causadas pelo aumento da temperatura tecidual, bem como destes efeitos na área paraincisional. O propósito deste estudo foi proporcionar a confecção de um plano piloto visando analisar macroscopicamente os efeitos da radiação laser de CO2 em tíbia de rato a fim de estabelecerem-se parâmetros de segurança quanto a potência. Foram utilizados 12 ratos. Após anestesia, os ossos foram submetidos a radiação com potência de 1, 3 e 5 watts. Os animais foram sacrificados nos tempos imediatamente após, 3, 7 e 14 dias após a irradiação, visando à remoção do osso tratado. Os espécimes obtidos foram observados através de lupa estereoscópica com aumentos de 14, 25 e 40 vezes e fotografados para posterior análise. Os resultados permitiram concluir que a potência de 1 watt proporciona uma melhor qualidade de resposta à reparação e que as potências de 3 e 5 watts provocaram o atraso na cronologia de reparo.The use of CO2 laser in osseous tissue to execute osteotomies is still questionable, mainly due to the increase of temperature in the site of irradiation. The purpose of this research was to carry out a pilot study in order to analyze macroscopically the effect of CO2 laser irradiation on rat tibia and to establish security parameters regarding power. Twelve rats were submitted to irradiation with 1, 3 and 5 watts of power and were examined immediately, 3, 7 and 14 days after irradiation. The results showed better healing when irradiation was carried out with the power of 1 watt; the 3- and 5-watt powers caused delay in the chronology of healing.

High power multiple wavelength diode laser stack for DPSSL application without temperature control

Science.gov (United States)

Hou, Dong; Yin, Xia; Wang, Jingwei; Chen, Shi; Zhan, Yun; Li, Xiaoning; Fan, Yingmin; Liu, Xingsheng

2018-02-01

High power diode laser stack is widely used in pumping solid-state laser for years. Normally an integrated temperature control module is required for stabilizing the output power of solid-state laser, as the output power of the solid-state laser highly depends on the emission wavelength and the wavelength shift of diode lasers according to the temperature changes. However the temperature control module is inconvenient for this application, due to its large dimension, high electric power consumption and extra adding a complicated controlling system. Furthermore, it takes dozens of seconds to stabilize the output power when the laser system is turned on. In this work, a compact hard soldered high power conduction cooled diode laser stack with multiple wavelengths is developed for stabilizing the output power of solid-state laser in a certain temperature range. The stack consists of 5 laser bars with the pitch of 0.43mm. The peak output power of each bar in the diode laser stack reaches as much as 557W and the combined lasing wavelength spectrum profile spans 15nm. The solidstate laser, structured with multiple wavelength diode laser stacks, allows the ambient temperature change of 65°C without suddenly degrading the optical performance.

Laser Fusion: status, future, and tritium control

International Nuclear Information System (INIS)

Coyle, P.E.

1978-11-01

At Livermore the 10 kJ, 20 to 30 TW Shiva facility is now operational and producing regular new fusion results. Design work has begun on a 200 to 300 TW laser designed to carry the program through the first breakeven demonstration experiments in the mid-1980's. Confidence in reaching this goal is based on the significant progress we have made in state-of-the-art, high-power Nd:glass laser technology, in experimental laser fusion and laser plasma interaction physics, and in theoretical and analytical computer codes which reliably model and predict experimental results. For all of these experiments, a variety of fusion targets are being fabricated in the laboratory, and the control and handling of tritium is now a regular and routine part of ongoing inertial fusion experiments. Target design with gains of about 1000 have been studied and the means to mass produce such pellets at low cost are also being developed

Control of ring lasers by means of coupled cavities

DEFF Research Database (Denmark)

Buchhave, Preben; Abitan, Haim; Tidemand-Lichtenberg, Peter

2000-01-01

Variable phase coupling to an external ring is used to control a unidirectional ring laser. The observed behavior of the coupled rings is explained theoretically. We have found experimentally that by quickly changing the phase of the feedback from the external ring it is possible to Q......-switch the ring laser. Also, at certain values of the phase of the feedback in the external ring, instabilities in the total system occur and oscillations arise in the ring laser....

Pancreatic capillary blood flow during caerulein-induced pancreatitis evaluated by a laser-doppler flowmeter in rats Estudo das alterações do fluxo capilar pancreático após infusão de ceruleína avaliado por laser-Doppler em ratos

Directory of Open Access Journals (Sweden)

Roberto Ferreira Meirelles Jr.

2003-01-01

Full Text Available PURPOSE: The pancreatic capillary blood flow (PCBF was studied to determine its alterations during caerulein-induced pancreatitis in rats. METHODS: Twenty rats were divided in groups: control and caerulein. A laser-Doppler flowmeter to measure PCBF continuously was used. Blood pressure (BP and heart rate (HR were monitored. Serum biochemistry analyses were determined. Histopathological study was performed. RESULTS: The PCBF measured a mean of 109.08 ± 14.54% and 68.24 ± 10.47% in control group and caerulein group, respectively. Caerulein group had a mean decrease of 31.75 ± 16.79%. The serum amylase was 1323.70 ± 239.10U.I-1 and 2184.60 ± 700.46U.I-1 in control and caerulein groups, respectively. There was a significant difference in the PCBF (pOBJETIVO: O fluxo capilar pancreático (FCP foi estudado para determinar suas alterações durante a pancreatite aguda induzida por ceruleína, em ratos. MÉTODOS: Vinte ratos foram divididos em grupo controle e grupo ceruleína. Um laser-Doppler fluxímetro foi empregado para determinar, continuamente, o FCP durante 120 minutos. A pressão arterial média (PAM e a freqüência cardíaca (FC foram determinadas, durante o experimento. Análise bioquímica sérica e estudo histopatológico, por microscopia ótica, do tecido pancreático foram realizados, ao final do experimento. RESULTADOS: O FCP foi em média 109,08 ± 2,17% e 68,24 ± 16,79% nos grupos controle e ceruleína , respectivamente. No grupo ceruleína, houve uma diminuição média de 31,75 ± 16,79%. Os níveis de amilase sérica foram de 1323,70 ± 239,10U.I-1 e 2184,60 ± 700,46U.I-1 nos grupos controle e ceruleína, respectivamente. Houve diferença significante (p<0,05 no FCP e na amilasemia, quando comparado o grupo controle com o grupo ceruleína. Embora micro e macrovacuolização estivessem presentes no grupo ceruleína, não houve diferença histológica entre os grupos. CONCLUSÃO: A diminuição do FCP parece um evento precoce

Measurements and simulation of controlled beamfront motion in the Laser Controlled Collective Accelerator

International Nuclear Information System (INIS)

Yao, R.L.; Destler, W.W.; Striffler, C.D.; Rodgers, J.; Scgalov, Z.

1989-01-01

In the Laser Controlled Collective Accelerator, an intense electron beam is injected at a current above the vacuum space charge limit into an initially evacuated drift tube. A plasma channel, produced by time-sequenced, multiple laser beam ionization of a solid target on the drift tube wall, provides the necessary neutralization to allow for effective beam propagation. By controlling the rate of production of the plasma channel as a function of time down the drift tube, control of the electron beamfront can be achieved. Recent experimental measurements of controlled beamfront motion in this configuration are presented, along with results of ion acceleration experiments conducted using two different accelerating gradients. These results are compared with numerical simulations of the system in which both controlled beamfront motion and ion acceleration is observed consistent with both design expectations and experimental results. 5 refs., 6 figs

Produtos naturais para o controle do ácaro Varroa destructor em abelhas africanizadas

Directory of Open Access Journals (Sweden)

Guido Laércio Bragança Castagnino

2012-06-01

Full Text Available O objetivo deste trabalho foi avaliar os efeitos do ácido oxálico e de óleos essenciais de plantas no controle da infestação pelo ácaro Varroa destructor em colônias de Apis mellifera africanizadas. O experimento foi realizado em delineamento inteiramente casualizado, em 30 colônias, com seis tratamentos e cinco repetições. As colmeias foram tratadas com óleos essenciais de arruda (Ruta graveolens, eucalipto (Eucalyptus spp. e hortelã (Mentha piperita, além de timol, ácido oxálico e do tratamento controle sem aplicação de produtos. Foram avaliadas a mortalidade de varroas e as taxas de mortalidade de crias e de infestação de varroas em crias e em abelhas adultas, antes e depois da aplicação de cada produto. O ácido oxálico e os óleos de arruda, timol, eucalipto e de hortelã reduziram a mortalidade de crias parasitadas pelo ácaro em 92,1, 83,3, 81,7, 86,4 e 81,3%, respectivamente. O tratamento com ácido oxálico reduziu em 87,4% a infestação de varroas em abelhas adultas. O uso desses produtos é eficiente na redução da mortalidade de crias de A. mellifera parasitadas por V. destructor.

Laser cooling in a feedback-controlled optical shaker

International Nuclear Information System (INIS)

Vilensky, Mark Y.; Averbukh, Ilya Sh.; Prior, Yehiam

2006-01-01

We explore the prospects of optical shaking, a recently suggested generic approach to laser cooling of neutral atoms and molecules. Optical shaking combines elements of Sisyphus cooling and of stochastic cooling techniques and is based on feedback-controlled interaction of particles with strong nonresonant laser fields. The feedback loop guarantees a monotonous energy decrease without a loss of particles. We discuss two types of feedback algorithms and provide an analytical estimation of their cooling rate. We study the robustness of optical shaking against noise and establish minimal stability requirements for the lasers. The analytical predictions are in a good agreement with the results of detailed numerical simulations

High brightness diode lasers controlled by volume Bragg gratings

Science.gov (United States)

Glebov, Leonid

2017-02-01

Volume Bragg gratings (VBGs) recorded in photo-thermo-refractive (PTR) glass are holographic optical elements that are effective spectral and angular filters withstanding high power laser radiation. Reflecting VBGs are narrow-band spectral filters while transmitting VBGs are narrow-band angular filters. The use of these optical elements in external resonators of semiconductor lasers enables extremely resonant feedback that provides dramatic spectral and angular narrowing of laser diodes radiation without significant power and efficiency penalty. Spectral narrowing of laser diodes by reflecting VBGs demonstrated in wide spectral region from near UV to 3 μm. Commercially available VBGs have spectral width ranged from few nanometers to few tens of picometers. Efficient spectral locking was demonstrated for edge emitters (single diodes, bars, modules, and stacks), vertical cavity surface emitting lasers (VCSELs), grating coupled surface emitting lasers (GCSELs), and interband cascade lasers (ICLs). The use of multiplexed VBGs provides multiwavelength emission from a single emitter. Spectrally locked semiconductor lasers demonstrated CW power from milliwatts to a kilowatt. Angular narrowing by transmitting VBGs enables single transverse mode emission from wide aperture diode lasers having resonators with great Fresnel numbers. This feature provides close to diffraction limit divergence along a slow axis of wide stripe edge emitters. Radiation exchange between lasers by means of spatially profiled or multiplexed VBGs enables coherent combining of diode lasers. Sequence of VBGs or multiplexed VBGs enable spectral combining of spectrally narrowed diode lasers or laser modules. Thus the use of VBGs for diode lasers beam control provides dramatic increase of brightness.

Cyanobacteria blooms cannot be controlled by effective microorganisms (EM) from mud- or Bokashi-balls

NARCIS (Netherlands)

Lürling, M.F.L.L.W.; Tolman, Y.; Oosterhout, J.F.X.

2010-01-01

In controlled experiments, the ability of ‘‘Effective Microorganisms (EM, in the form of mudballs or Bokashi-balls)’’ was tested for clearing waters from cyanobacteria. We found suspensions of EM-mudballs up to 1 g l-1 to be ineffective in reducing cyanobacterial growth. In all controls and

Eficiência do laser diodo 980 nm em comparação à da glicose a 75% na oclusão de veias da orelha de coelhos The efficiency of the diode laser 980 nm compared to glucose 75% in occlusion of the veins in rabbit ears

Directory of Open Access Journals (Sweden)

Paulo Roberto da Silva Lima

2011-06-01

Full Text Available CONTEXTO: Por ser o laser um método novo no tratamento das varizes, há muitos mitos e dúvidas com relação à sua eficácia; assim, surgiu a necessidade de compará-lo a substância esclerosante mais utilizada em nosso meio (glicose hipertônica. OBJETIVO: Comparar a eficiência do laser diodo 980 nm à glicose 75% na oclusão de veias em orelha de coelho. MÉTODOS: Ensaio aleatório em animais de laboratório por 21 dias. A amostra consistiu de orelhas de coelhos machos adultos. Grupo L (laser: 15 orelhas tratadas com laser; grupo G (glicose 75%: 15 orelhas tratadas com glicose a 75%. Variáveis primárias: veias esclerosadas e/ou ocluídas. Variáveis complementares: volume da substância administrada, complicações e peso. O tamanho da amostra foi estimado em 30 orelhas. Foi realizado o teste exato de Fisher associado ao Risco Relativo (RR, calculando-se o intervalo de confiança (IC de 95% para as variáveis acima. RESULTADOS: A incidência de esclerose ou oclusão venosa no grupo G foi de 53% (8/15; IC95%: 27-79 e no grupo L, 20% (3/15; IC95%: 4-49. O p bicaudal foi de 0,1281, o RR usando a aproximação de Katz foi de 2,66; IC95%: 0,87-8,15. CONCLUSÃO: A eficiência do laser diodo 980 nm em comparação à da glicose 75% na oclusão de veias para o modelo experimental estudado foi equivalente.BACKGROUND: The laser is a new treatment to varicose veins and there is several myths and doubts in relation to its efficacy; then, there is the need to compare it with the most commonly sclerosing solution (hypertonic glucose used in our specialty. OBJECTIVE: To compare the efficiency of the diode laser 980nm to the glucose 75% in the occlusion of veins from the ear of rabbits. METHODS: Aleatory trial in laboratory animals during 21 days. The sample consisted of ears from male adult rabbits. Group L (laser: 15 ears treated with laser; group G (glucose 75%: 15 ears treated with glucose 75%. Primary variables: sclerotic and/or occluded veins

Laser-based measuring equipment controlled by microcomputer

International Nuclear Information System (INIS)

Miron, N.; Sporea, D.; Velculescu, V.G.; Petre, M.

1988-03-01

Some laser-based measuring equipment controlled by microcomputer developed for industrial and scientific purposes are described. These equipments are intended for dial indicators verification, graduated rules measurement, and for very accurate measurement of the gravitational constant. (authors)

UMA ANÁLISE DE PESQUISAS REALIZADAS SOBRE CONTROLE DE GESTÃO EM EMPRESAS INTERNACIOLIZADAS

Directory of Open Access Journals (Sweden)

Thiago de Abreu Costa

2014-12-01

Full Text Available O presente estudo se propõe, através de uma revisão bibliográfica que abrange as dissertações e artigos produzidos pela Universidade Estadual do Rio de Janeiro nos últimos 10 anos, a estudar os sistemas de controle gerencial, buscando evidenciar possíveis modificações em função do processo de internacionalização. Os resultados embora não possam ser generalizados, reforçam as conclusões de que existem circunstâncias em que o processo de internacionalização de uma empresa não envolve, necessariamente, uma ampla sofisticação e complexidade do sistema de controle gerencial. Além disso, alguns estudos realizados por Rodrigues e Gomes (2005, coincidem em alguns aspectos da literatura, em especial o emprego de mecanismos formais de controle financeiro, e discordam em outros, tendo em vista que as decisões encontram-se centralizadas na direção geral e os centros de responsabilidades não possuem autonomia.   The present study proposes using a literature review covering the lectures and articles produced by the State University of Rio de Janeiro in the last 10 years to study the management control systems, seeking evidence of possible changes due to the process of internationalization. Although the results can not be generalized, reinforce the conclusions that there are circumstances in which the process of internationalization of a firm does not necessarily involve a wide sophistication and complexity of the management control system. Moreover, it was perceived the use of formal financial controls, centralization in the general direction of the organizations and the limited autonomy of the centers of responsibility.

Controllable generation of reactive oxygen species by femtosecond-laser irradiation

Science.gov (United States)

Yan, Wei; He, Hao; Wang, Yintao; Wang, Yisen; Hu, Minglie; Wang, Chingyue

2014-02-01

Femtosecond lasers have been advancing Biophotonics research in the past two decades with multiphoton microscopy, microsurgery, and photodynamic therapy. Nevertheless, laser irradiation is identified to bring photodamage to cells via reactive oxygen species (ROS) generation with unclear mechanism. Meanwhile, currently in biological researches, there is no effective method to provide controllable ROS production precisely, which originally is leaked from mitochondria during respiration and plays a key role in a lot of important cellular processes and cellular signaling pathways. In this study, we show the process of how the tightly focused femtosecond-laser induces ROS generation solely in mitochondria at the very beginning and then release to cytosol if the stimulus is intense enough. At certain weak power levels, the laser pulses induce merely moderate Ca2+ release but this is necessary for the laser to generate ROS in mitochondria. Cellular original ROS are also involved with a small contribution. When the power is above a threshold, ROS are then released to cytosol, indicating photodamage overwhelming cellular repair ability. The mechanisms in those two cases are quite different. Those results clarify parts of the mechanism in laser-induced ROS generation. Hence, it is possible to further this optical scheme to provide controllable ROS generation for ROS-related biological researches including mitochondrial diseases and aging.

Controllable generation of reactive oxygen species by femtosecond-laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Yan, Wei; He, Hao, E-mail: haohe@tju.edu.cn; Wang, Yintao; Wang, Yisen; Hu, Minglie; Wang, Chingyue [Ultrafast Laser Laboratory, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin (China)

2014-02-24

Femtosecond lasers have been advancing Biophotonics research in the past two decades with multiphoton microscopy, microsurgery, and photodynamic therapy. Nevertheless, laser irradiation is identified to bring photodamage to cells via reactive oxygen species (ROS) generation with unclear mechanism. Meanwhile, currently in biological researches, there is no effective method to provide controllable ROS production precisely, which originally is leaked from mitochondria during respiration and plays a key role in a lot of important cellular processes and cellular signaling pathways. In this study, we show the process of how the tightly focused femtosecond-laser induces ROS generation solely in mitochondria at the very beginning and then release to cytosol if the stimulus is intense enough. At certain weak power levels, the laser pulses induce merely moderate Ca{sup 2+} release but this is necessary for the laser to generate ROS in mitochondria. Cellular original ROS are also involved with a small contribution. When the power is above a threshold, ROS are then released to cytosol, indicating photodamage overwhelming cellular repair ability. The mechanisms in those two cases are quite different. Those results clarify parts of the mechanism in laser-induced ROS generation. Hence, it is possible to further this optical scheme to provide controllable ROS generation for ROS-related biological researches including mitochondrial diseases and aging.

Controllable generation of reactive oxygen species by femtosecond-laser irradiation

International Nuclear Information System (INIS)

Yan, Wei; He, Hao; Wang, Yintao; Wang, Yisen; Hu, Minglie; Wang, Chingyue

2014-01-01

Femtosecond lasers have been advancing Biophotonics research in the past two decades with multiphoton microscopy, microsurgery, and photodynamic therapy. Nevertheless, laser irradiation is identified to bring photodamage to cells via reactive oxygen species (ROS) generation with unclear mechanism. Meanwhile, currently in biological researches, there is no effective method to provide controllable ROS production precisely, which originally is leaked from mitochondria during respiration and plays a key role in a lot of important cellular processes and cellular signaling pathways. In this study, we show the process of how the tightly focused femtosecond-laser induces ROS generation solely in mitochondria at the very beginning and then release to cytosol if the stimulus is intense enough. At certain weak power levels, the laser pulses induce merely moderate Ca 2+ release but this is necessary for the laser to generate ROS in mitochondria. Cellular original ROS are also involved with a small contribution. When the power is above a threshold, ROS are then released to cytosol, indicating photodamage overwhelming cellular repair ability. The mechanisms in those two cases are quite different. Those results clarify parts of the mechanism in laser-induced ROS generation. Hence, it is possible to further this optical scheme to provide controllable ROS generation for ROS-related biological researches including mitochondrial diseases and aging

The laser control system for the TRIUMF optically pumped polarized H- ion source

International Nuclear Information System (INIS)

Kadantsev, S.G.; Levy, C.D.P.; Mouat, M.M.

1994-08-01

The optically pumped polarized H - ion source at TRIUMF produces up to 100 μΑ dc of 78% polarized beam within an emittance of 1.0 π mm mrad and is now being prepared for an upcoming experiment at TRIUMF that will measure parity violation in pp scattering at 230 MeV. The optical pumping is accomplished by argon laser pumped Ti-sapphire lasers. The laser control system provides monitoring and precision control of the lasers for fast spin reversal up to 200 s -1 . To solve the problems of laser power and frequency stabilization during fast spin flipping, techniques and algorithms have been developed that significantly reduce the variation of laser frequency and power between spin states. The upgraded Faraday rotation system allows synchronous measurement of Rb thickness and polarization while spin flipping. The X Window environment provides both local and remote control to laser operators via a local area network and X window terminals. In this new environment issues such as access authorization, response time, operator interface consistency and ease of use are of particular importance. (author)

Lócus de controle em saúde e autoestima em portadores de diabetes mellitus tipo 2

Directory of Open Access Journals (Sweden)

Fernanda Silva Fuscaldi

2011-08-01

Full Text Available O presente estudo teve como objetivo relacionar os escores obtidos pela aplicação das escalas de lócus de controle da saúde e autoestima com variáveis sócio-demográficas, clínicas, fatores de risco e complicações crônicas em 65 portadores de diabetes mellitus do tipo 2. Trata-se de um estudo descritivo transversal onde foram utilizados, para a análise estatística, os testes de Qui-quadrado de Pearson, Mann-Whitney, Kruskal-Wallis e de Correlação de Spearman. Em relação ao lócus de controle, os pacientes apresentaram, em média, maiores escores na dimensão interna, sendo que as mulheres demonstraram maior externalidade-ao acaso para a saúde. Relações estatisticamente significativas foram encontradas entre internalidade com tempo de diagnóstico e atividade física; entre externalidade-outros poderosos com hemoglobina glicada e atividade física e entre externalidade-ao acaso com a prática de atividade física. A autoestima foi alta na maioria dos indivíduos, porém não se relacionou estatisticamente a nenhuma variável.

Laser-activated nano-biomaterials for tissue repair and controlled drug release

International Nuclear Information System (INIS)

Matteini, P; Ratto, F; Rossi, F; Pini, R

2014-01-01

We present recent achievements of minimally invasive welding of biological tissue and controlled drug release based on laser-activated nano-biomaterials. In particular, we consider new advancements in the biomedical application of near-IR absorbing gold nano-chromophores as an original solution for the photothermal repair of surgical incisions and as nanotriggers of controlled drug release from hybrid biopolymer scaffolds. (laser biophotonics)

Vibration control for the ARGOS laser launch path

Science.gov (United States)

Peter, Diethard; Gässler, Wolfgang; Borelli, Jose; Barl, Lothar; Rabien, S.

2012-07-01

Present and future adaptive optics systems aim for the correction of the atmospheric turbulence over a large field of view combined with large sky coverage. To achieve this goal the telescope is equipped with multiple laser beacons. Still, to measure tip-tilt aberrations a natural guide star is used. For some fields such a tilt-star is not available and a correction on the laser beacons alone is applied. For this method to work well the laser beacons must not be affected by telescope vibrations on their up-link path. For the ARGOS system the jitter of the beacons is specified to be below 0.05. To achieve this goal a vibration compensation system is necessary to mitigate the mechanical disturbances. The ARGOS vibration compensation system is an accelerometer based feed forward system. The accelerometer measurements are fed into a real time controller. To achieve high performance the controller of the system is model based. The output is applied to a fast steering mirror. This paper presents the concept of the ARGOS vibration compensation, the hardware, and laboratory results.

Distributed Nd-YAG laser welding and process control in inert glove boxes

International Nuclear Information System (INIS)

Milewski, J.O.; Lewis, G.K.; Barbe, M.R.; Cremers, D.A.

1993-01-01

We have fabricated and assembled a fiber optic delivered ND-YAG laser welding work station that consists of three glove boxes served by a single 1kw laser. Processing considerations related to the welding of special nuclear materials, toxic materials and complex part geometry are addressed within each work cell. We are proceeding with a development effort to integrate the equipment capabilities with remote sensing, process monitoring and control systems. These systems will provide real time data acquisition during welding, monitoring and verification of weld parameters, and CAD/CAM to CNC generated positioning paths. Computerized information storage, retrieval and network methods are used for weld process documentation and data analysis. A virtual control panel is being configured to integrate the monitoring and control operation of individual subsystems, such as laser and motion control into a single graphical interface. Development work on sensors to monitor laser beam characteristics and weld depth in real time with potential for adaptive control is in progress. System capabilities and results of these development efforts are presented

Misturas em tanque com glyphosate para o controle de trapoeraba, erva-de-touro e capim-carrapicho em soja RR®

Directory of Open Access Journals (Sweden)

Cleber Daniel de Goes Maciel

2011-02-01

Full Text Available O uso de misturas de glyphosate, em tanque, para manejo de espécies de plantas daninhas de difícil controle tem sido prática comum entre os agricultores brasileiros. Desta forma, este trabalho teve como objetivo avaliar a eficácia e seletividade de misturas, em tanque, de herbicidas com glyphosate para o controle de trapoeraba (Commelina benghalensis L., erva-de-touro (Tridax procumbens L. e capim-carrapicho (Cenchrus echinatus L. na cultura da soja RR®. O experimento foi conduzido em Maracaí, São Paulo, no período de novembro de 2006 a março de 2007, utilizando-se o cultivar CD-214RR® e delineamento experimental de blocos ao acaso, com 21 tratamentos e quatro repetições. Os tratamentos foram constituídos da aplicação de: glyphosate (180; 360; 540 e 720 g ha-1; glyphosate em sequencial (180/360; 360/360 e 540/360 g ha-1; glyphosate + chlorimuron-ethyl 360+10; 540+10; 360+5/ 360+5 g ha-1; glyphosate + lactofen (360+120; 540+120; 360+60/ 360+60 g ha-1; glyphosate + cloransulam-methyl (360+30; 540+30; 360+16,9/ 360+12,9 g ha-1; glyphosate + carfentrazone (360+4 g ha-1; glyphosate + imazethapyr (360+50 g ha-1; glyphosate + imazethapyr (177,8+30 g ha-1 e testemunhas capinada e sem capina. Apesar da similaridade de produtividade de grãos entre os tratamentos com glyphosate isolado e sequencial, nas doses 540, 720 e 540/ 360 g ha-1, as misturas em tanque com chlorimuron-ethyl, cloransulam-methyl, lactofen e imazethapyr favoreceram o controle de espécies de plantas daninhas tolerantes ao glyphosate como C. benghalensis e T. procumbens.

Method and apparatus for laser-controlled proton beam radiology

Science.gov (United States)

Johnstone, Carol J.

1998-01-01

A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H.sup.- beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H.sup.- beam and laser beam to produce a neutral beam therefrom within a subsection of the H.sup.- beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H.sup.- beam in order to form the neutral beam in subsections of the H.sup.- beam. As the scanning laser moves across the H.sup.- beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser.

In vitro conjunctival incision repair by temperature-controlled laser soldering.

Science.gov (United States)

Norman, Galia; Rabi, Yaron; Assia, Ehud; Katzir, Abraham

2009-01-01

The common method of closing conjunctival incisions is by suturing, which is associated with several disadvantages. It requires skill to apply and does not always provide a watertight closure, which is required in some operations (e.g., glaucoma filtration). The purpose of the present study was to evaluate laser soldering as an alternative method for closing conjunctival incisions. Conjunctival incisions of 20 ex vivo porcine eyes were laser soldered using a temperature-controlled fiberoptic laser system and an albumin mixed with indocyanine green as a solder. The control group consisted of five repaired incisions by a 10-0 nylon running suture. The leak pressure of the repaired incisions was measured. The mean leak pressure in the laser-soldered group was 132 mm Hg compared to 4 mm Hg in the sutured group. There was no statistically significant difference in both the incision's length and distance from the limbus between the groups, before and after the procedure, indicating that there was no severe thermal damage. These preliminary results clearly demonstrate that laser soldering may be a useful method for achieving an immediate watertight conjunctival wound closure. This procedure is faster and easier to apply than suturing.

Influência da irradiação do laser na regeneração nervosa em diferentes locais de tratamento Influence of laser radiation in nerve regeneration in different treatment sites

Directory of Open Access Journals (Sweden)

Fausto Fernandes de Almeida Sousa

2009-01-01

Full Text Available OBJETIVO: Verificar a influência do laser de baixa intensidade de AsGaAl na lesão por esmagamento do nervo peroneiro de ratos através da avaliação funcional da marcha nos diferentes locais de irradiação. MÉTODOS: Foram utilizados 53 ratos, divididos em seis grupos: normal, lesado não tratado, lesado e tratado placebo, lesado e tratado na medula, lesado e tratado no nervo, lesado e tratado em ambos (nervo e medula. O esmagamento do nervo peroneiro foi realizado por meio de uma pinça e subsequente tratado com laser por 28 dias consecutivos. Na avaliação funcional foram analisadas as impressões das pegadas, registradas pela câmera de vídeo em uma passarela de acrílico, no pré-operatório e aos 14º, 21º e 28º dias de pós-operatório, e avaliadas na fórmula PFI por meio do software. RESULTADOS: Na avaliação funcional da marcha foram encontradas diferenças significantes somente no 14º dia de pós-operatório. CONCLUSÃO: A irradiação do laser AsGaAl de baixa intensidade foi capaz de acelerar e potencializar o processo de regeneração nervosa periférica de ratos no 14º dia de pós-operatório, de acordo com a avaliação funcional da marcha, tanto para o grupo tratado na medula quanto para o grupo tratado no nervo.OBJECTIVE: This study seeks to determine, through functional gait assessment in different irradiation sites, the influence of a low-intensity GaAsAl laser beam on an injury caused by crushing the peroneal nerve in rats. METHODS: 53 rats were used, which were divided into six groups: normal, injured and untreated, injured and treated using placebo, injured and treated in the bone marrow, injured and treated in the nerve, and injured and treated in both (nerve and bone marrow. The peroneal nerve was crushed using a pair of tweezers, and subsequently treated with laser for 28 consecutive days. The functional gait evaluation analyzed the footprints, which were recorded with a video camera on an acrylic bridge in the

Automatic laser beam position control on the Isolde-Rilis experiment

CERN Document Server

Grancharova, D; Fedosseev, V; Suberlucq, Guy; CERN. Geneva. AB Department

2003-01-01

The On-Line Isotope Mass Separator ISOLDE at CERN is a facility for production of radioactive ion beams by the interaction of proton beams with a thick target. One of the most widely used types of ion source at ISOLDE is a chemically selective laser ion source based on the method of laser ionization of atoms in a hot cavity - RILIS (Resonance Ionization Laser Ion Source). The optical set-up of RILIS includes three copper vapour lasers, a set of dye lasers and frequency multiplication crystals giving up to three different beams of tuneable wavelengths. This paper will focus on the transport of the laser beams to the targets at distances of 18 m and 23 m, the development of the acquisition of their position and finally the automatic control of optics for an accurate alignment.

Avaliação da eficácia do laser de baixa intensidade no tratamento das disfunções têmporo-mandibular: estudo clínico randomizado

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Maria Helena Chaves de Vasconcelos Catão

2013-12-01

Full Text Available OBEJTIVO: avaliar a eficácia do laser de baixa intensidade no tratamento da dor em pacientes com desordens temporomandibulares. MÉTODO:consistiu de um ensaio clínico randomizado divididos em dois grupos: Grupo 1: laser AsGaAl, Grupo 2: laser InGaAlP, do qual participaram 20 pacientes entre 19 e 35 anos de idade, com diagnóstico de sinais e sintomas de DTM. Os pacientes tinham a amplitude de movimento para abertura máxima da boca e lateralidade registados no início e no final do tratamento a laser. O Laser foi aplicado em quatro pontos pré-auriculares, totalizando 12 sessões três vezes por semana, durante um mês. Dor dos pacientes foi registrado com base na utilização da escala analógica visual (EAV e também por exame físico dos pontos álgicos. RESULTADOS: observou-se redução significante (p<0,028 do nível de dor em ambos os grupos, porém no G1 a significância foi maior. A evolução do limiar de sensibilidade muscular evidenciou diferença estatisticamente significante (p<0,05 para G1 e G2. A laserterapia no Grupo 1 melhorou a abertura bucal em média de 4,643 mm, enquanto no Grupo 2, a média foi de 3,71 mm por paciente. CONCLUSÃO: houve eficácia em ambos os lasers no controle da dor e abertura bucal dos pacientes.

Controlling Plasma Channels through Ultrashort Laser Pulse Filamentation

Science.gov (United States)

Ionin, Andrey; Seleznev, Leonid; Sunchugasheva, Elena

2013-09-01

A review of studies fulfilled at the Lebedev Institute in collaboration with the Moscow State University and Institute of Atmospheric Optics in Tomsk on influence of various characteristics of ultrashort laser pulse on plasma channels formed under its filamentation is presented. Filamentation of high-power laser pulses with wavefront controlled by a deformable mirror, with cross-sections spatially formed by various diaphragms and with different wavelengths was experimentally and numerically studied. An application of plasma channels formed due to filamentation of ultrashort laser pulse including a train of such pulses for triggering and guiding long electric discharges is discussed. The research was supported by RFBR Grants 11-02-12061-ofi-m and 11-02-01100, and EOARD Grant 097007 through ISTC Project 4073 P

USO DE NATAMICINA NO CONTROLE DO DESENVOLVIMENTO DE FUNGOS EM SALAME TIPO ITALIANO

OpenAIRE

Jean Carlos Brustolin

2009-01-01

Este trabalho teve como objetivo avaliar o comportamento da natamicina em diferentes concentrações e forma de aplicação no controle do desenvolvimento de bolores e leveduras em salames tipo italiano maturados em salas de maturação de madeira. O acompanhamento foi realizado através de contagem de bolores e leveduras com swabs e acompanhamento fotográfico semanal. Também foi avaliado o efeito da natamicina em relação a aspectos físico químicos como a atividade de água, umidade, gordura e pro...

Uses of ORACLE in the Nova Laser Control System

International Nuclear Information System (INIS)

McGuigan, D.L.

1983-01-01

The Nova Laser System is a large-scale fusion experiment being constructed at the Lawrence Livermore National Laboratory. Modern control system technology is required to efficiently manage the thousands of devices needed to operate the system. In order to reduce the requirements on the operations staff, much of the system is being automated. This requires a significant knowledge base including frequently used system configurations and device parameters. We will be using ORACLE to provide this information to the control system. To insure the control-system integrity, ORACLE will be used to maintain information about the control-system software. This information will be used to document the system as well as help track down problems. ORACLE will also be used to maintain data on the system performance. This data will be analyzed to optimize the laser performance and point out when maintenance is required

CONTROLE PÓS-COLHEITA DA PODRIDÃO PARDA DO PESSEGUEIRO COM FUNGICIDAS EM PRÉ-COLHEITA E TRICHODERMA EM PÓS-COLHEITA

OpenAIRE

Elizandra Pivotto Pavanello

2012-01-01

O objetivo do presente trabalho foi avaliar a eficiência da aplicação pré-colheita de fungicidas no controle da podridão parda em pós-colheita e verificar o seu efeito quando associado a fungos antagonistas, assegurando eficiência no controle da doença e qualidade dos frutos. Para tanto, avaliou-se o efeito da aplicação de fungicidas em pré-colheita no controle da podridão parda do pessegueiro após 15 e 40 dias de armazenamento refrigerado dos frutos, além da associação de fungicidas com o tr...

Multiplatform Mobile Laser Scanning: Usability and Performance

Directory of Open Access Journals (Sweden)

Yuwei Chen

2012-08-01

Full Text Available Mobile laser scanning is an emerging technology capable of capturing three-dimensional data from surrounding objects. With state-of-the-art sensors, the achieved point clouds capture object details with good accuracy and precision. Many of the applications involve civil engineering in urban areas, as well as traffic and other urban planning, all of which serve to make 3D city modeling probably the fastest growing market segment in this field. This article outlines multiplatform mobile laser scanning solutions such as vehicle- and trolley-operated urban area data acquisition, and boat-mounted equipment for fluvial environments. Moreover, we introduce a novel backpack version of mobile laser scanning equipment for surveying applications in the field of natural sciences where the requirements include precision and mobility in variable terrain conditions. In addition to presenting a technical description of the systems, we discuss the performance of the solutions in the light of various applications in the fields of urban mapping and modeling, fluvial geomorphology, snow-cover characterization, precision agriculture, and in monitoring the effects of climate change on permafrost landforms. The data performance of the mobile laser scanning approach is described by the results of an evaluation of the ROAMER on a permanent MLS test field. Furthermore, an <em>in> <em>situ> accuracy assessment using a field of spherical 3D targets for the newly-introduced Akhka backpack system is conducted and reported on.

Control of ion beam generation in intense short pulse laser target interaction

International Nuclear Information System (INIS)

Nagashima, T.; Izumiyama, T.; Barada, D.; Kawata, S.; Gu, Y.J.; Wang, W.M.; Ma, Y.Y.; Kong, Q.

2013-01-01

In intense laser plasma interaction, several issues still remain to be solved for future laser particle acceleration. In this paper we focus on a control of generation of high-energy ions. In this study, near-critical density plasmas are employed and are illuminated by high intensity short laser pulses; we have successfully generated high-energy ions, and also controlled ion energy and the ion energy spectrum by multiple-stages acceleration. We performed particle-in-cell simulations in this paper. The first near-critical plasma target is illuminated by a laser pulse, and the ions accelerated are transferred to the next target. The next identical target is also illuminated by another identical large pulse, and the ion beam introduced is further accelerated and controlled. In this study four stages are employed, and finally a few hundreds of MeV of protons are realized. A quasi-monoenergetic energy spectrum is also obtained. (author)

A PASSIVELY MODE-LOCKED CR4+:FORSTERITE LASER WITH ELEСTRONICALLY CONTROLLED OUTPUT CHARACTERISTICS

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S. A. Zolotovskaya

2011-01-01

Full Text Available Applicability of electronic control of laser output parameters to bulk solid-state laser sources is demonstrated. A single laser source with variable pulse duration for novel imaging and manipulation systems is presented. Stable passive mode-locking of a Cr4+:forsterite laser using a voltage controlled p-n junction quantum dot saturable absorber was achieved. Output shortening from 17,4 to 6,4 ps near-transform limited pulses was obtained by applying reverse bias.

Soliton self-frequency shift controlled by a weak seed laser in tellurite photonic crystal fibers.

Science.gov (United States)

Liu, Lai; Meng, Xiangwei; Yin, Feixiang; Liao, Meisong; Zhao, Dan; Qin, Guanshi; Ohishi, Yasutake; Qin, Weiping

2013-08-01

We report the first demonstration of soliton self-frequency shift (SSFS) controlled by a weak continuous-wave (CW) laser, from a tellurite photonic crystal fiber pumped by a 1560 nm femtosecond fiber laser. The control of SSFS is performed by the cross-gain modulation of the 1560 nm femtosecond laser. By varying the input power of the weak CW laser (1560 nm) from 0 to 1.17 mW, the soliton generated in the tellurite photonic crystal fiber blue shifts from 1935 to 1591 nm. The dependence of the soliton wavelength on the operation wavelength of the weak CW laser is also measured. The results show the CW laser with a wavelength tunable range of 1530-1592 nm can be used to control the SSFS generation.

Os efeitos do laser hélio-neônio de baixa intensidade na cicatrização de lesões cutâneas induzidas em ratos Effects of low-level helium-neon laser on induced wound healing in rats

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Viviane L. Busnardo

2010-02-01

Full Text Available OBJETIVO: Avaliar os efeitos do laser de baixa potência hélio e neônio (HeNe na cicatrização de feridas cutâneas de ratos. MÉTODOS: Sessenta ratos Wistar foram divididos em grupos controle e experimento. Utilizou-se ferida incisional, longitudinal, dorso-mediana, suturada com pontos separados simples. No grupo experimento, as feridas foram irradiadas diariamente com aparelho de laser de HeNe com potência contínua máxima de 5mW, comprimento de onda de 632,8 nm, visível com densidade de energia de 4J/cm², área de raio do laser de 0,015cm², durante 36 segundos, em três pontos da lesão. As feridas foram avaliadas no 3º, no 7º e no 14º dia de pós-operatório. Cortes histológicos foram corados com hematoxilina-eosina (H&E e avaliados segundo protocolo de Vizzotto et al. (2003* para identificar o tipo de reação inflamatória e com Picrosirius para identificar os colágenos I e III e o índice de maturidade da cicatriz (IMaC. Utilizou-se imunoistoquímica com anti-CD45-LCA para o reconhecimento das células inflamatórias. RESULTADOS: Ambos os grupos mostraram o mesmo padrão inflamatório. No grupo experimento, observaram-se menos células inflamatórias nos três tempos estudados (pOBJECTIVE: To evaluate the effects of low-level helium-neon (HeNe laser on cutaneous wound healing in rats. METHODS: Sixty Wistar rats were divided into control group and experimental group. A sutured longitudinal, dorsal-medial incision was made, with simple separate stitches. The experimental group was irradiated daily in three areas of the wound with HeNe laser (5mW maximum continuous power, 632.8 nm wavelength, 4 J/cm² energy density and 0.015 cm² laser beam area for 36 seconds. The areas were evaluated on the third, seventh and fourteenth days postoperative. Histological sections were stained with hematoxylin-eosin to determine the type of inflammatory reaction according to the protocol by Vizzotto et al. (2003* and with Picrosirius to identify

Short-pulse lasers for weather control

Science.gov (United States)

Wolf, J. P.

2018-02-01

Filamentation of ultra-short TW-class lasers recently opened new perspectives in atmospheric research. Laser filaments are self-sustained light structures of 0.1–1 mm in diameter, spanning over hundreds of meters in length, and producing a low density plasma (1015–1017 cm‑3) along their path. They stem from the dynamic balance between Kerr self-focusing and defocusing by the self-generated plasma and/or non-linear polarization saturation. While non-linearly propagating in air, these filamentary structures produce a coherent supercontinuum (from 230 nm to 4 µm, for a 800 nm laser wavelength) by self-phase modulation (SPM), which can be used for remote 3D-monitoring of atmospheric components by Lidar (Light Detection and Ranging). However, due to their high intensity (1013–1014 W cm‑2), they also modify the chemical composition of the air via photo-ionization and photo-dissociation of the molecules and aerosols present in the laser path. These unique properties were recently exploited for investigating the capability of modulating some key atmospheric processes, like lightning from thunderclouds, water vapor condensation, fog formation and dissipation, and light scattering (albedo) from high altitude clouds for radiative forcing management. Here we review recent spectacular advances in this context, achieved both in the laboratory and in the field, reveal their underlying mechanisms, and discuss the applicability of using these new non-linear photonic catalysts for real scale weather control.

Controllable superhydrophobic aluminum surfaces with tunable adhesion fabricated by femtosecond laser

Science.gov (United States)

Song, Yuxin; Wang, Cong; Dong, Xinran; Yin, Kai; Zhang, Fan; Xie, Zheng; Chu, Dongkai; Duan, Ji'an

2018-06-01

In this study, a facile and detailed strategy to fabricate superhydrophobic aluminum surfaces with controllable adhesion by femtosecond laser ablation is presented. The influences of key femtosecond laser processing parameters including the scanning speed, laser power and interval on the wetting properties of the laser-ablated surfaces are investigated. It is demonstrated that the adhesion between water and superhydrophobic surface can be effectively tuned from extremely low adhesion to high adhesion by adjusting laser processing parameters. At the same time, the mechanism is discussed for the changes of the wetting behaviors of the laser-ablated surfaces. These superhydrophobic surfaces with tunable adhesion have many potential applications, such as self-cleaning surface, oil-water separation, anti-icing surface and liquid transportation.

Benchmarking Advanced Control Algorithms for a Laser Scanner System

DEFF Research Database (Denmark)

Stoustrup, Jakob; Ordys, A.W.; Smillie, I.

1996-01-01

The paper describes tests performed on the laser scanner system toassess feasibility of modern control techniques in achieving a requiredperformance in the trajectory following problem. The two methods tested areQTR H-infinity and Predictive Control. The results are ilustated ona simulation example....

Chaotic behaviour and controlling chaos in free electron lasers

International Nuclear Information System (INIS)

Wang Wenjie; Chen Shigang; Du Xiangwan; Wang Guangrui

1995-01-01

Chaos in free electron lasers (FEL) is reviewed. Special attention has been paid to the chaotic behaviour of the electrons and the laser field. The problem of controlling and utilizing chaotic motion of the electrons and the laser field has also been discussed. In order to find out the rules of instability and chaos in FEL, some typical methods of the chaotic theory are used. These methods include making the Poincare surface of section, drawing the phase space diagrams of the electron orbits, calculating the Liapunov exponents, and computing the power spectrum, etc. Finally, some problems in FEL research are discussed (103 refs., 54 figs.)

A frequency-type optically controllable YAG:Nd(3+) laser

Energy Technology Data Exchange (ETDEWEB)

Baliasnyi, L.M.; Groznov, M.A.; Gubanov, B.S.; Zoria, A.V.; Myl' nikov, V.S.

1990-06-01

The paper demonstrates the feasibility of using MOS-LC modulators based on the s-effect with an internal dividing mirror as the optically controllable mirrors of frequency-type YAG:Nd(3+) lasers. It is shown that the maximum energy of the laser in free-runnig operation of 10 mJ/sq cm is limited by the radiation resistance (not greater than 70 mJ/sq cm) of the orienting fluid, i.e., polyvinyl alcohol. The optical inhomogeneity of the modulator amounts to 20-40 percent, which is connected with the presence of a bonded single-crystal GaAs layer. The working frequency of the laser was about 20 Hz.

Experimental control of the beam properties of laser-accelerated protons and carbon ions

Energy Technology Data Exchange (ETDEWEB)

Amin, Munib

2008-12-15

The laser generation of energetic high quality beams of protons and heavier ions has opened up the door to a plethora of applications. These beams are usually generated by the interaction of a short pulse high power laser with a thin metal foil target. They could already be applied to probe transient phenomena in plasmas and to produce warm dense matter by isochoric heating. Other applications such as the production of radioisotopes and tumour radiotherapy need further research to be put into practice. To meet the requirements of each application, the properties of the laser-accelerated particle beams have to be controlled precisely. In this thesis, experimental means to control the beam properties of laser-accelerated protons and carbon ions are investigated. The production and control of proton and carbon ion beams is studied using advanced ion source designs: Experiments concerning mass-limited (i.e. small and isolated) targets are conducted. These targets have the potential to increase both the number and the energy of laser-accelerated protons. Therefore, the influence of the size of a plane foil target on proton beam properties is measured. Furthermore, carbon ion sources are investigated. Carbon ions are of particular interest in the production of warm dense matter and in cancer radiotherapy. The possibility to focus carbon ion beams is investigated and a simple method for the production of quasi-monoenergetic carbon ion beams is presented. This thesis also provides an insight into the physical processes connected to the production and the control of laser-accelerated ions. For this purpose, laser-accelerated protons are employed to probe plasma phenomena on laser-irradiated targets. Electric fields evolving on the surface of laser-irradiated metal foils and hollow metal foil cylinders are investigated. Since these fields can be used to displace, collimate or focus proton beams, understanding their temporal and spatial evolution is crucial for the design of

Experimental control of the beam properties of laser-accelerated protons and carbon ions

International Nuclear Information System (INIS)

Amin, Munib

2008-12-01

The laser generation of energetic high quality beams of protons and heavier ions has opened up the door to a plethora of applications. These beams are usually generated by the interaction of a short pulse high power laser with a thin metal foil target. They could already be applied to probe transient phenomena in plasmas and to produce warm dense matter by isochoric heating. Other applications such as the production of radioisotopes and tumour radiotherapy need further research to be put into practice. To meet the requirements of each application, the properties of the laser-accelerated particle beams have to be controlled precisely. In this thesis, experimental means to control the beam properties of laser-accelerated protons and carbon ions are investigated. The production and control of proton and carbon ion beams is studied using advanced ion source designs: Experiments concerning mass-limited (i.e. small and isolated) targets are conducted. These targets have the potential to increase both the number and the energy of laser-accelerated protons. Therefore, the influence of the size of a plane foil target on proton beam properties is measured. Furthermore, carbon ion sources are investigated. Carbon ions are of particular interest in the production of warm dense matter and in cancer radiotherapy. The possibility to focus carbon ion beams is investigated and a simple method for the production of quasi-monoenergetic carbon ion beams is presented. This thesis also provides an insight into the physical processes connected to the production and the control of laser-accelerated ions. For this purpose, laser-accelerated protons are employed to probe plasma phenomena on laser-irradiated targets. Electric fields evolving on the surface of laser-irradiated metal foils and hollow metal foil cylinders are investigated. Since these fields can be used to displace, collimate or focus proton beams, understanding their temporal and spatial evolution is crucial for the design of

Nuclear reactivity control using laser induced polarization

International Nuclear Information System (INIS)

Bowman, C.D.

1990-01-01

This patent describes a control element for reactivity control of a fission source provides an atomic density of 3 He in a control volume which is effective to control criticality as the 3 He is spin-polarized. Spin-polarization of the 3 He affects the cross section of the control volume for fission neutrons and hence, the reactivity. An irradiation source is directed within the 3 He for spin-polarizing the 3 He. An alkali-metal vapor may be included with the 3 He where a laser spin-polarizes the alkali-metal atoms which in turn, spin-couple with 3 He to spin-polarize the 3 He atoms

Inibição da expressão de ciclooxigenase 2 em feridas cutâneas de camundongos NOD submetidos à terapia a laser de baixa intensidade Inhibition of cyclooxygenase 2 expression in NOD mice cutaneous wound by low-level laser therapy

Directory of Open Access Journals (Sweden)

Carolina de Lourdes Julião Vieira Rocha

2012-09-01

Full Text Available CONTEXTO: A terapia a laser de baixa intensidade (LLLT tem sido relatada como importante moduladora da cicatrização de feridas cutâneas aumentando a proliferação fibroblástica associada ao aumento da expressão da citocina fator transformador de crescimento- β2 (TGF-βB2. OBJETIVO: No presente estudo foram avaliados os efeitos da LLLT sobre a expressão da enzima ciclooxigenase 2 (COX2 no sítio do reparo tecidual utilizando o modelo experimental com camundongos diabéticos não obesos (NOD para estudar a cicatrização de feridas cutâneas. MÉTODOS: Foram utilizados 30 camundongos NOD, destes 14 ficaram diabéticos e foram divididos em dois grupos: o grupo I (n=7 foi submetido a um procedimento cirúrgico de feridas cutâneas e o grupo II (n=7 foi submetido a um procedimento cirúrgico de feridas cutâneas e tratados com LLLT. O grupo II foi submetido à LLLT nos seguintes parâmetros: 15 mW de potência, dose de 3,8 J/cm² e tempo de aplicação de 20 segundos. Após sete dias do ato cirúrgico e após aplicação do laser, os animais foram eutanasiados com sobredose de anestesia e amostras das feridas foram colhidas para posterior análise histopatológica, histomorfométrica e imuno-histoquímica. RESULTADOS: A LLLT promoveu a inibição da expressão da COX2 em feridas cutâneas de camundongos diabéticos. CONCLUSÃO: Em conjunto, os resultados sugeriram que a LLLT é capaz de modular negativamente a expressão da enzima COX2 contribuindo para o controle da resposta inflamatória em feridas cutâneas de camundongos NOD.BACKGROUND: Low-level laser therapy (LLLT has been reported to modulate the healing of wounds by inducing an increase in fibroblast number associated with increased expression of the cytokine transforming growth factor-β2 (TGF-β2. OBJECTIVE: In the present study, the effect of LLLT on expression of COX2 at the site of tissue repair was evaluated, using an experimental model with non obese diabetic mice (NOD to study

Efecto de extractos vegetales de <em>Polygonum hydropiperoidesem>, <em>Solanum nigrumem> y <em>Calliandra pittieriem> sobre el gusano cogollero (<em>Spodoptera frugiperdaem>

Directory of Open Access Journals (Sweden)

Lizarazo H. Karol

2008-12-01

Full Text Available

El gusano cogollero <em>Spodoptera frugiperdaem> es una de las plagas que más afectan los cultivos en la región de Sumapaz (Cundinamarca, Colombia. En la actualidad se controla principalmente aplicando productos de síntesis química, sin embargo la aplicación de extractos vegetales surge como una alternativa de menor impacto sobre el ambiente. Este control se emplea debido a que las plantas contienen metabolitos secundarios que pueden inhibir el desarrollo de los insectos. Por tal motivo, la presente investigación evaluó el efecto insecticida y antialimentario de extractos vegetales de barbasco <em>Polygonum hydropiperoidesem> (Polygonaceae, carbonero <em>Calliandra pittieriem> (Mimosaceae y hierba mora <em>Solanum nigrumem> (Solanaceae sobre larvas de <em>S. frugiperdaem> biotipo maíz. Se estableció una cría masiva del insecto en el laboratorio utilizando una dieta natural con hojas de maíz. Posteriormente se obtuvieron extractos vegetales utilizando solventes de alta polaridad (agua y etanol y media polaridad (diclorometano los cuales se aplicaron sobre las larvas de segundo instar. Los resultados más destacados se presentaron con extractos de <em>P. hydropiperoidesem>, obtenidos con diclorometano en sus diferentes dosis, con los cuales se alcanzó una mortalidad de 100% 12 días después de la aplicación y un efecto antialimentario representado por un consumo de follaje de maíz inferior al 4%, efectos similares a los del testigo comercial (Clorpiriphos.

Random fiber laser based on artificially controlled backscattering fibers.

Science.gov (United States)

Wang, Xiaoliang; Chen, Daru; Li, Haitao; She, Lijuan; Wu, Qiong

2018-01-10

The random fiber laser (RFL), which is a milestone in laser physics and nonlinear optics, has attracted considerable attention recently. Most previously reported RFLs are based on distributed feedback of Rayleigh scattering amplified through the stimulated Raman-Brillouin scattering effect in single-mode fibers, which require long-distance (tens of kilometers) single-mode fibers and high threshold, up to watt level, due to the extremely small Rayleigh scattering coefficient of the fiber. We proposed and demonstrated a half-open-cavity RFL based on a segment of an artificially controlled backscattering single-mode fiber with a length of 210 m, 310 m, or 390 m. A fiber Bragg grating with a central wavelength of 1530 nm and a segment of artificially controlled backscattering single-mode fiber fabricated by using a femtosecond laser form the half-open cavity. The proposed RFL achieves thresholds of 25 mW, 30 mW, and 30 mW, respectively. Random lasing at a wavelength of 1530 nm and extinction ratio of 50 dB is achieved when a segment of 5 m erbium-doped fiber is pumped by a 980 nm laser diode in the RFL. A novel RFL with many short cavities has been achieved with low threshold.

High-order dispersion control of 10-petawatt Ti:sapphire laser facility.

Science.gov (United States)

Li, Shuai; Wang, Cheng; Liu, Yanqi; Xu, Yi; Li, Yanyan; Liu, Xingyan; Gan, Zebiao; Yu, Lianghong; Liang, Xiaoyan; Leng, Yuxin; Li, Ruxin

2017-07-24

A grism pair is utilized to control the high-order dispersion of the Shanghai Superintense Ultrafast Lasers Facility, which is a large-scale project aimed at delivering 10-PW laser pulses. We briefly present the characteristics of the laser system and calculate the cumulative B-integral, which determines the nonlinear phase shift influence on material dispersion. Three parameters are selected, grism separation, angle of incidence and slant distance of grating compressor, to determine their optimal values through an iterative searching procedure. Both the numerical and experimental results confirm that the spectral phase distortion is controlled, and the recompressed pulse with a duration of 24 fs is obtained in the single-shot mode. The distributions and stabilities of the pulse duration at different positions of the recompressed beam are also investigated. This approach offers a new feasible solution for the high-order dispersion compensation of femtosecond petawatt laser systems.

Low-level laser therapy with 940 nm diode laser on stability of dental implants: a randomized controlled clinical trial.

Science.gov (United States)

Torkzaban, Parviz; Kasraei, Shahin; Torabi, Sara; Farhadian, Maryam

2018-02-01

Low-level laser therapy (LLLT) is a non-invasive modality to promote osteoblastic activity and tissue healing. The aim of this study was to evaluate the efficacy of LLLT for improvement of dental implant stability. This randomized controlled clinical trial was performed on 80 dental implants placed in 19 patients. Implants were randomly divided into two groups (n = 40). Seven sessions of LLLT (940 nm diode laser) were scheduled for the test group implants during 2 weeks. Laser was irradiated to the buccal and palatal sides. The same procedure was performed for the control group implants with laser hand piece in "off" mode. Implant stability was measured by Osstell Mentor device in implant stability quotient (ISQ) value immediately after surgery and 10 days and 3, 6, and 12 weeks later. Repeated measures ANOVA was used to compare the mean ISQ values (implant stability) in the test and control groups. Statistical test revealed no significant difference in the mean values of implant stability between the test and control groups over time (P = 0.557). Although the mean values of implant stability changed significantly in both groups over time (P laser group in the first weeks and increased from the 6th to 12th week, LLLT had no significant effect on dental implant stability.

A efetividade do laser de HeNe 632,8 nm no reestabelecimento da integridade dos tecidos cutâneos em animais experimentais: revisão sistemática Effectiveness of HeNe 632.8 nm laser on skin tissue integrity repair in experimental animals: a systematic review

Directory of Open Access Journals (Sweden)

Clarissa Tôrres Leal

2012-09-01

Full Text Available O objetivo desta revisão sistemática foi analisar o efeito do laser de HeNe na cicatrização de feridas em ratos. Foram selecionados estudos experimentais que adotaram o laser HeNe para o tratamento de feridas agudas em ratos adultos saudáveis, com lesões induzidas por bisturi, nas bases de dados PubMed/MEDLINE, LILACS e SciELO. Foram utilizados os seguintes descritores: cicatrização de feridas e colágeno, de acordo com o MeSH e o DeCS, além dos unitermos laser HeNe e reparação da pele e seus equivalentes em inglês e espanhol. Três estudos foram incluídos na revisão sistemática, não sendo possível a realização de metanálise, devido à impossibilidade de comparação entre as metodologias dos estudos selecionados. Todos os estudos realizaram análise por meio de cortes histológicos das cicatrizes. A presença de falhas metodológicas nos três artigos dificultou a interpretação fidedigna dos dados encontrados. Os estudos destacaram uma redução na intensidade da resposta inflamatória e uma melhor organização das fibras colágenas no grupo irradiado. A terapia com laser HeNe mostrou boa resposta no reparo tecidual. No entanto, tais resultados devem ser analisados de modo criterioso, uma vez que há presença de heterogeneidade, principalmente em relação aos parâmetros adotados.The aim of this systematic review was to analyze the effect of HeNe laser on wound healing in rats. Experimental studies that adopted HeNe laser as a treatment of acute lesions in healthy adult rats were selected, with scalpel-induced lesions, at PubMed/MEDLINE, LILACS, and SciELO databases. The following keywords were used: wound healing and collagen, according to MeSH and DeCS, besides the terms HeNe laser and skin repair, and their equivalent in Portuguese and Spanish. Three studies were included in this systematic review, but it was not possible to perform a metanalysis, due to impossibility to compare methods of the selected studies. All

The Effect of Laser Treatment as a Weed Control Method

DEFF Research Database (Denmark)

Mathiassen, Solvejg K; Bak, Thomas; Christensen, Svend

2006-01-01

at the cotyledon stage. Experiments were carried out under controlled conditions, using pot-grown weeds. Two lasers and two spot sizes were tested and different energy doses were applied by varying the exposure time. The biological efficacy was examined on three different weed species: Stellaria media (common...... was related to wavelength, exposure time, spot size and laser power. The efficacy also varied between the weed species. The results indicate that the efficacy of laser treatments can be improved by a more precise pointing of the laser beam towards the apical meristems and optimisation of the energy density...... (exposure time and spot size of the laser beam). The experiment also showed a significant difference between two wavelengths. In order to improve the performance and to validate the efficacy on a broader spectrum of weed species, further research and development is needed....

Controle de dispositivos em estufa agrícola / Agricultural greenhouse control of devices

Directory of Open Access Journals (Sweden)

Ricardo A. Bona

2008-05-01

Full Text Available Este artigo mostra a possibilidade de se coletar dados e controlar dispositivos e sensores através das portas serial e paralela de um computador, com aplicabilidade em uma estufa agrícola. Os dados coletados são: temperatura, umidade, pressão, estado da porta de acesso e das janelas. Os dispositivos controlados são: janela motorizada, exaustor, torneira e lâmpada. Um software está sendo desenvolvido para analisar, em tempo real, os dados coletados de sensores e realizar o controle dos dispositivos, tomando decisões como, por exemplo, abertura ou fechamento da janela da estufa. O software analisa, também, variáveis coletadas dos sensores e mostra resultados obtidos de forma gráfi ca

Laser control of atomic beam motion and applications

International Nuclear Information System (INIS)

Balykin, V.I.; Letokhov, V.S.

1987-01-01

The authors present the results of an experimental investigation of the control of atomic beam motion by the light pressure of laser radiation. Collimation, focusing and reflection of the atomic beam are considered. Collimation of the atomic beam is achieved by the interaction of laser radiation with atoms, when the light pressure force depends only on the atom's velocity. A similar regime of atomic beam interaction with radiation was performed with transversal irradiation of a beam by the axis-symmetrical field. The axis-symmetrical field was formed by laser radiation reflected from the conical mirror surface of a reflecting axicon. The axis of the atomic beam coincided with that of the axicon. The collimation regime was reached under negative detuning of the laser radiation frequency from the atomic transition frequency by a value equal to several homogeneous widths. With positive detuning by the same value the regime of beam decollimation was observed. The density of atoms on the beam axis was changed by 10 3 times, when the collimation regime was replaced by that of decollimation. Focusing of the atomic beam was achieved by light pressure dependent on the atomic coordinate. Focusing was performed within the field configuration formed by divergent laser Gaussian beams propagating in the direction +- X, +- Y of a Cartesian coordinate system. Waists of the laser beams were an equal distance from the atomic beam axis. With an atomic beam propagating along the z axis, expressions for local distance and a formula for the laser lens were obtained. Focusing of the atomic beam was experimentally accomplished, and the image of the atomic beam was received. In this work they also investigated reflection of the atomic beam by laser radiation. The possibility of creating the optics of a neutral atomic beam is shown

Padronização e caracterização da tecnologia laser em borracha EPDM para o design de joias contemporâneas

Directory of Open Access Journals (Sweden)

Mariana Kuhl Cidade

2016-12-01

Full Text Available Esta pesquisa trata da geração de referência de padronização na utilização da tecnologia de corte a laser CO2 em borracha EPDM, através do desenvolvimento de joias contemporâneas. Foram conduzidos diversos testes de aplicação de velocidades e número de passadas de feixe laser a fim de determinar a configuração ideal para utilização deste processo no material. Imagens analisadas via MEV auxiliaram a compreensão dos efeitos do feixe laser no elastômero, como a zona de abrangência térmica e a efetividade do corte. Com a melhor definição de corte para um traço uniforme, essa caracterização objetiva auxiliar estudantes, profissionais e indústrias na execução de seus projetos.

A Novel Apoptosis Correlated Molecule: Expression and Characterization of Protein Latcripin-1 from <em>Lentinula em>edodes> C_91–3

Full Text Available An apoptosis correlated molecule—protein Latcripin-1 of <em>Lentinula> edodesem> C_91-3—was expressed and characterized in <em>Pichia pastorisem> GS115. The total RNA was obtained from <em>Lentinula edodesem> C_91–3. According to the transcriptome, the full-length gene of Latcripin-1 was isolated with 3'-Full Rapid Amplification of cDNA Ends (RACE and 5'-Full RACE methods. The full-length gene was inserted into the secretory expression vector pPIC9K. The protein Latcripin-1 was expressed in <em>Pichia pastorisem> GS115 and analyzed by Sodium Dodecylsulfonate Polyacrylate Gel Electrophoresis (SDS-PAGE and Western blot. The Western blot showed that the protein was expressed successfully. The biological function of protein Latcripin-1 on A549 cells was studied with flow cytometry and the 3-(4,5-Dimethylthiazol-2-yl-2,5-Diphenyl-tetrazolium Bromide (MTT method. The toxic effect of protein Latcripin-1 was detected with the MTT method by co-culturing the characterized protein with chick embryo fibroblasts. The MTT assay results showed that there was a great difference between protein Latcripin-1 groups and the control group (<em>p em>< 0.05. There was no toxic effect of the characterized protein on chick embryo fibroblasts. The flow cytometry showed that there was a significant difference between the protein groups of interest and the control group according to apoptosis function (<em>p em>< 0.05. At the same time, cell ultrastructure observed by transmission electron microscopy supported the results of flow cytometry. The work demonstrates that protein Latcripin-1 can induce apoptosis of human lung cancer cells A549 and brings new insights into and advantages to finding anti-tumor proteins.

SOFTWARE TOOL FOR LASER CUTTING PROCESS CONTROL – SOLVING REAL INDUSTRIAL CASE STUDIES

Directory of Open Access Journals (Sweden)

Miloš Madić

2016-08-01

Full Text Available Laser cutting is one of the leading non-conventional machining technologies with a wide spectrum of application in modern industry. It order to exploit a number of advantages that this technology offers for contour cutting of materials, it is necessary to carefully select laser cutting conditions for each given workpiece material, thickness and desired cut qualities. In other words, there is a need for process control of laser cutting. After a comprehensive analysis of the main laser cutting parameters and process performance characteristics, the application of the developed software tool “BRUTOMIZER” for off-line control of CO2 laser cutting process of three different workpiece materials (mild steel, stainless steel and aluminum is illustrated. Advantages and abilities of the developed software tool are also illustrated.

National Ignition Facility, subsystem design requirements beam control and laser diagnostics SSDR 1.7

International Nuclear Information System (INIS)

Bliss, E.

1996-01-01

This Subsystem Design Requirement document is a development specification that establishes the performance, design, development, and test requirements for the Alignment subsystem (WBS 1.7.1), Beam Diagnostics (WBS 1.7.2), and the Wavefront Control subsystem (WBS 1.7. 3) of the NIF Laser System (WBS 1.3). These three subsystems are collectively referred to as the Beam Control ampersand Laser Diagnostics Subsystem. The NIF is a multi-pass, 192-beam, high-power, neodymium-glass laser that meets requirements set forth in the NIF SDR 002 (Laser System). 3 figs., 3 tabs

Active stabilization of a rapidly chirped laser by an optoelectronic digital servo-loop control.

Science.gov (United States)

Gorju, G; Jucha, A; Jain, A; Crozatier, V; Lorgeré, I; Le Gouët, J-L; Bretenaker, F; Colice, M

2007-03-01

We propose and demonstrate a novel active stabilization scheme for wide and fast frequency chirps. The system measures the laser instantaneous frequency deviation from a perfectly linear chirp, thanks to a digital phase detection process, and provides an error signal that is used to servo-loop control the chirped laser. This way, the frequency errors affecting a laser scan over 10 GHz on the millisecond timescale are drastically reduced below 100 kHz. This active optoelectronic digital servo-loop control opens new and interesting perspectives in fields where rapidly chirped lasers are crucial.

Comparison of H-infinity control and generalized predictive control for a laser scanner system

DEFF Research Database (Denmark)

Ordys, A.W.; Stoustrup, Jakob; Smillie, I.

2000-01-01

This paper describes tests performed on a laser scanner system to assess the feasibility of H-infinity control and generalized predictive control design techniques in achieving a required performance in a trajectory folowing problem. The two methods are compared with respect to achieved scan times...

Control and data management for a large fusion laser

International Nuclear Information System (INIS)

Davis, J.W.; Holloway, F.W.

1975-01-01

SHIVA is a powerful (10-kJ 25 TW) neodymium glass laser system to be used (in 1977) for target irradiation in fusion research. SHIVA is also a development project in that it is pushing the state of the art in laser and optical technology. The present design calls for 20 parallel laser amplification chains whose light output is pointed and focused at a small (100 μ) target within a chamber from semi-equally spaced three-dimensional directions. It is probable that SHIVA will be upgraded to as many as 42 chains in the next few years. Each chain of SHIVA contains 7 high energy laser amplifiers and perhaps 20 other major optical components, many of which send and receive control and measurement information. Again future expansion may add additional elements. Each chain has also associated 10 gimbal or translation motions for beam assignment from the oscillator onto the target

Pulsed-diode-pumped, all-solid-state, electro-optically controlled picosecond Nd:YAG lasers

International Nuclear Information System (INIS)

Gorbunkov, Mikhail V; Shabalin, Yu V; Konyashkin, A V; Kostryukov, P V; Olenin, A N; Tunkin, V G; Morozov, V B; Rusov, V A; Telegin, L S; Yakovlev, D V

2005-01-01

The results of the development of repetitively pulsed, diode-pumped, electro-optically controlled picosecond Nd:YAG lasers of two designs are presented. The first design uses the active-passive mode locking with electro-optical lasing control and semiconductor saturable absorber mirrors (SESAM). This design allows the generation of 15-50-ps pulses with an energy up to 0.5 mJ and a maximum pulse repetition rate of 100 Hz. The laser of the second design generates 30-ps pulses due to combination of positive and negative electro-optical feedback and the control of the electro-optical modulator by the photocurrent of high-speed semiconductor structures. (active media. lasers)

Controlling the optical field chaos in storage ring free-electron lasers

International Nuclear Information System (INIS)

Wang Wenjie

1995-01-01

The controlling of optical field chaos in a storage ring free-electron laser oscillator is discussed by using a phenomenal model. A novel method (which is called the 'beating method') of controlling chaos in a nonlinear dynamical system described by non-autonomous ordinary differential equations was developed. The result of theoretical analysis and numerical simulation shows that the optical field chaos in a storage ring free-electron laser oscillator can be suppressed and a periodic laser intensity can be obtained when a weak periodic control field is added to the optical cavity. The validity of this method of eliminating chaos is confirmed by the fact that the leading Lyapunov characteristic exponent of the system changes from a positive real number to a negative one. A further research is carried out, and it is found that only when the period of the control field equals to an integral multiple of that of the gain modulation in the optical cavity can the optical field chaos be suppressed. This means that the 'beating method' of controlling chaos is a kind of resonant method. A way to determine the 'best beating position' in the phase trajectory has also been obtained

Control strategies for laser separation of carbon isotopes

Indian Academy of Sciences (India)

Unknown

Control strategies for laser separation of carbon isotopes. V PARTHASARATHY*, A K ... The emerging market for medical applications of C-13 is projected to be in the range of hundreds of ..... thermal effects during irradiation. In the absence of ...

Essential oils for rust control on coffee plants Óleos essenciais no controle da ferrugem em cafeeiro

Directory of Open Access Journals (Sweden)

Ricardo Borges Pereira

2012-02-01

Full Text Available Rust is considered the most important disease in coffee because it causes severe defoliation in plants and, consequently, reduction in productivity. This study evaluated the in vitro effect of essential oils of cinnamon, citronella, lemongrass, clove, tea tree, thyme, neem and eucalyptus on the germination of urediniospores of Hemileia vastatrix; the effectiveness of these oils to control rust on seedlings of coffee cultivars Catucaí 2SL, Catuaí IAC 62 and Mundo Novo 379/19 in the greenhouse; and the effect of more promising oils on urediniospores of H. vastatrix by transmission electron microscopy (TEM. All the essential oils inhibited the germination of urediniospores with increasing concentrations. All oils promoted partial control of the disease in the greenhouse. However, the oils of thyme, clove and citronella, at a concentration of 1000 µL L-1, were most effective in controlling the disease on cultivars Catucaí 2SL, Catuaí IAC 62 and Mundo Novo 379/19, respectively. The images generated in TEM showed that urediniospores exposed to oils of clove, citronella and thyme promoted cellular disorganization and cytoplasmic vacuolization, which was more pronounced in urediniospores exposed to citronella oil. The oils of thyme, clove and citronella are promising for the control of rust in coffee.A ferrugem é considerada a doença de maior importância no cafeeiro, pois causa acentuada desfolha nas plantas e, consequentemente, redução na produtividade. Este trabalho avaliou o efeito in vitro de óleos essenciais de canela, citronela, capim-limão, cravo-da-índia, árvore-de-chá, tomilho, nim e eucalipto na germinação de urediniósporos de Hemileia vastatrix; a eficácia desses óleos no controle da ferrugem em mudas de cafeeiro das cultivares Catucaí 2SL, Catuaí IAC 62 e Mundo Novo 379/19 em casa de vegetação; e o efeito dos óleos mais promissores sobre urediniósporos de H. vastatrix por meio de microscopia eletrônica de transmiss

Effects of the low-intensity laser therapy on the prevention of dental caries induced in rats; Efeitos da radiacao laser em baixa intensidade na prevencao de carie dental induzida em ratos

Energy Technology Data Exchange (ETDEWEB)

Mueller, Karin Praia

2004-07-01

The purpose of this study was to investigate the effects of low intensity laser therapy, associated or not to an acidulated phosphate fluoride, on the prevention of dental caries induced in rats. It was used 40 wistar rats, female, weaned with 18 days, fed with a cariogenic diet during 48 days and inoculated orally with Streptococcus mutans by three consecutive days starting from the second day of the diet. On the fifth day of experiment the animals were divided into five groups: G{sub c} (control) the animas were no submitted to any treatment; G{sub L} (laser) irradiation with low power laser (GaAlAs, {lambda}=660 nm, P=30 mW, {delta}t=5 sec, 5 J/cm{sup 2}); G{sub F} (fluoride) topical application of acidulated phosphate fluoride (APF 1,23%) for four minutes; G{sub LF} (laser + fluoride) irradiation with low power laser followed by topical application of acidulated phosphate fluoride; G{sub FL} (fluoride + laser) topical application of acidulated phosphate fluoride followed by low power laser. The animals were sacrificed after 48 days; the molars were extracted and prepared to determine the dental caries lesions area by optical microscopy, enamel microhardness and analysis of the calcium and phosphorus ratio (Ca/P) by energy dispersive spectroscopy. The results were statistically analyzed by ANOVA (plaser radiation associated with acidulated phosphate fluoride reduces the caries area and could be an alternative in the prevention of the dental caries. (author)

Adaptive feedforward control for improving output power response of CO2 laser; Tekiogata feedforward ni yoru laser shutsuryoku oto no kaizen

Energy Technology Data Exchange (ETDEWEB)

Imai, Y.; Takahashi, t.; Morita, A. [Mitsubishi Electric Corp., Tokyo (Japan)

1998-03-31

Feedback control has been used to stabilize the steady-state output power of a CO2 laser to overcome the problems caused by the change in the temperature/deterioration of CO2 gas. The transient response, however, is as slow as a few hundred milliseconds because of the slow dynamics of a thermopile power sensor. When machining conditions of a CO2 laser are changed, this rather slow response requires an extra dwell time, resulting in low productivity of the machining. To cope with this problem, the authors have developed adaptive feedforward control for a CO2 laser in addition to conventional feedback control. The model of a CO2 laser is described as a gain, which is varied by the setting parameters; laser power, pulse frequency and duty factor, as well as gas conditions. In this paper, two new variables, effective discharge power and threshold discharge power, are introduced to obtain a compact and adjustable model. With the proposed control system, the step response time of a laser power is reduced to less than ten milliseconds without overshoot, and can be set to desired constant time. The effects of such a fast and stable response on the machining speed and machining quality are examined. The experimental results show that for thin metal line-cutting, neither the melt-off area nor dross is observed even in the no-dwell time case. For thin metal hole-cutting, the machining speed is improved by 30%. 11 refs., 14 figs., 3 tabs.

Higher order sliding mode control of laser pointing for orbital debris mitigation

Science.gov (United States)

Palosz, Arthur

This thesis explores the use of a space-based laser to clean up small orbital debris from near Earth space. This system's challenge is to quickly and precisely aim the laser beam at very small (laser beam onto the orbital debris. A Kalman Filter (KF) is designed to accurately track the orbital debris and generate a command signal for the controller. A second order Super Twisting Sliding Mode Controller (2-SMC) is designed to follow the command signal generated by the KF and to overcome the parametric uncertainties and external disturbances. The performance of the system is validated with a computer simulation created in MATLAB and Simulink.

Controlling Stimulated Brillouin/Raman Scattering in High Power Fiber Lasers

Science.gov (United States)

2017-08-09

AFRL-RD-PS- AFRL-RD-PS- TR-2017-0043 TR-2017-0043 CONTROLLING STIMULATED BRILLOUIN/RAMAN SCATTERING IN HIGH POWER FIBER LASERS Cody Mart Ben...average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed...unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT This research addressed suppression of stimulated Brillouin/Raman scattering in high power fiber lasers

Laser beam pointing and stabilization by fractional-order PID control: Tuning rule and experiments

KAUST Repository

Al-Alwan, Asem Ibrahim Alwan; Guo, Xingang; Ndoye, Ibrahima; Laleg-Kirati, Taous-Meriem

2017-01-01

This paper studies the problem of high-precision positioning of laser beams by using a robust Fractional-Order Proportional-Integral-Derivative (FOPID) controller. The control problem addressed in laser beams aims to maintain the position of the laser beam on a Position Sensing Device (PSD) despite the effects of noise and active disturbances. The FOPID controller is well known for its simplicity with better tuning flexibility along with robustness to noise and output disturbance rejections. Thus, a control strategy based on FOPID to achieve the control objectives has been proposed. The FOPID gains and differentiation orders are optimally tuned in order to fulfill the robustness design specifications by solving a nonlinear optimization problem. A comparison to the conventional Proportional-Integral-Derivative (PID) and robust PID is also provided from simulation and experiment set-up. Due to sensor noise, practical PID controllers that filter the position signal before taking the derivative have been also proposed. Experimental results show that the requirements are totally met for the laser beam platform to be stabilized.

Laser beam pointing and stabilization by fractional-order PID control: Tuning rule and experiments

KAUST Repository

Al-Alwan, Asem Ibrahim Alwan

2017-10-24

This paper studies the problem of high-precision positioning of laser beams by using a robust Fractional-Order Proportional-Integral-Derivative (FOPID) controller. The control problem addressed in laser beams aims to maintain the position of the laser beam on a Position Sensing Device (PSD) despite the effects of noise and active disturbances. The FOPID controller is well known for its simplicity with better tuning flexibility along with robustness to noise and output disturbance rejections. Thus, a control strategy based on FOPID to achieve the control objectives has been proposed. The FOPID gains and differentiation orders are optimally tuned in order to fulfill the robustness design specifications by solving a nonlinear optimization problem. A comparison to the conventional Proportional-Integral-Derivative (PID) and robust PID is also provided from simulation and experiment set-up. Due to sensor noise, practical PID controllers that filter the position signal before taking the derivative have been also proposed. Experimental results show that the requirements are totally met for the laser beam platform to be stabilized.

Remote control radioactive-waste removal system uses modulated laser transmitter

Science.gov (United States)

Burcher, E. E.; Kopia, L. P.; Rowland, C. W.; Sinclair, A. R.

1971-01-01

Laser remote control system consists of transmitter, auto tracker, and receiver. Transmitter and tracker, packaged together and bore sighted, constitute control station, receiver is slave station. Model has five command channels and optical link operating range of 110 m.

Controlling branching in streamer discharge by laser background ionization

International Nuclear Information System (INIS)

Takahashi, E; Kato, S; Furutani, H; Sasaki, A; Kishimoto, Y

2011-01-01

Irradiation with a KrF laser controlled the positive streamer branching in atmospheric argon gas. This laser irradiation changed the amount of background ionization before the streamer discharge. Measuring the ionization current allowed us to evaluate the initial electron density formed by the KrF laser. We observed characteristic feather-like branching structure and found that it was only suppressed in the irradiated region. The threshold of ionization density which can influence the branching was evaluated to be 5 x 10 5 cm -3 . The relationship between the size of avalanche head and mean distance between initial electrons explained this suppression behaviour. These experimental results support that the feather-like structure originates from the branching model of Loeb-Meek, a probabilistic merging of individual avalanches.

Studies of ion acceleration in a one meter laser controlled collective accelerator

International Nuclear Information System (INIS)

Destler, W.W.; Rodgers, J.; Striffler, C.D.; Yao, R.L.

1991-01-01

The basic concept behind the Laser Controlled Beam-front Experiment has been described in detail in previous reports. In the experiment, control over the propagation of a virtual cathode at the front of an intense relativistic electron beam is achieved by a time-sequenced plasma channel produced by laser-target interactions. Ions are trapped and accelerated by the very strong electric fields (50-400 MV/m) at the virtual cathode

The control and data acquisition system of a laser in-vessel viewing system

International Nuclear Information System (INIS)

Pereira, Rita C.; Cruz, Nuno; Neri, C.; Riva, M.; Correia, C.; Varandas, C.A.F.

2000-01-01

This paper presents the dedicated control and data acquisition system (CADAS) of a new laser in-vessel viewing system that has been developed for inspection purposes in fusion experiments. CADAS is based on a MC68060 microprocessor and on-site developed VME instrumentation. Its main aims are to simultaneously control the laser alignment system as well as the laser beam deflection for in-vessel scanning, acquire a high-resolution image and support real-time data flow rates up to 2 Mbyte/s from the acquisition modules to the hard disk and network. The hardware (modules for control and alignment acquisition, scanning acquisition and monitoring) as well as the three levels of software are described

Phase control of a Zeeman-split He-Ne gas laser by variation of the gaseous discharge voltage.

Science.gov (United States)

Shelton, W N; Hunt, R H

1992-07-20

Zeeman-split lasers are useful for precise positioning or motion control. In applications that employ such a laser to control closely the position of a moving system, phase noise in the Zeeman frequency is a serious problem. Control of low-frequency phase noise can be obtained through variation of the external magnetic field by way of a solenoid wound around the laser tube. It is the finding in this work that control of the residual higher-frequency noise of a He-Ne laser can be obtained through small variations of the high voltage that is used to effect the gaseous discharge in the laser tube. The application of the present system is to the control of the path difference in a Fourier-transform interferometric spectrometer.

Highly Controlled Codeposition Rate of Organolead Halide Perovskite by Laser Evaporation Method.

Science.gov (United States)

Miyadera, Tetsuhiko; Sugita, Takeshi; Tampo, Hitoshi; Matsubara, Koji; Chikamatsu, Masayuki

2016-10-05

Organolead-halide perovskites can be promising materials for next-generation solar cells because of its high power conversion efficiency. The method of precise fabrication is required because both solution-process and vacuum-process fabrication of the perovskite have problems of controllability and reproducibility. Vacuum deposition process was expected to achieve precise control; however, vaporization of amine compound significantly degrades the controllability of deposition rate. Here we achieved the reduction of the vaporization by implementing the laser evaporation system for the codeposition of perovskite. Locally irradiated continuous-wave lasers on the source materials realized the reduced vaporization of CH 3 NH 3 I. The deposition rate was stabilized for several hours by adjusting the duty ratio of modulated laser based on proportional-integral control. Organic-photovoltaic-type perovskite solar cells were fabricated by codeposition of PbI 2 and CH 3 NH 3 I. A power-conversion efficiency of 16.0% with reduced hysteresis was achieved.

Eficácia do florfenicol e da oxitetraciclina no controle de Aeromonas hydrophila em pacu (Piaractus mesopotamicus

Directory of Open Access Journals (Sweden)

S.P. Carraschi

2011-06-01

Full Text Available Determinou-se a concentração eficaz de oxitetraciclina (OTC e florfenicol (FFC no tratamento de Aeromonas hydrophila em pacu (Piaractus. mesopotamicus. Os pacus foram submetidos à captura duas vezes ao dia por quatro dias e em seguida foram infectados com A. hydrophila (2,4x10(7 bactéria mL-1. Os tratamentos utilizados foram: controle sem infecção (CSI, controle com infecção (CCI e tratados com 110,0; 140,0 e 170,0mgOTC.kg-1, e 5,0; 10,0 e 15,0mgFFC.kg-1. As variáveis de qualidade da água foram monitoradas diariamente. Após o tratamento, no CSI dos dois testes, ocorreu 100% de sobrevivência. Nos testes com OTC, no CCI, a sobrevivência foi de 29,2%; em 110,0mg.kg-1, 37,5%; em 140,0mg.kg-1, 29,2%; e em 170,0mg.kg-1, 50,0%. Nos testes com FFC, foi eficaz com 10,0mg.kg-1, e no CCI a sobrevivência foi de 76,9%; em 5,0mg.kg-1, 81,81%; em 10,0mg/L.kg-1, 100% e em 15,0mg.kg-1, 87,5%. A OTC, em concentrações de até 170,0mg.kg-1 de ração, não é eficaz para o controle de A. hydrophila em pacu, e o FFC é eficaz na concentração de 10,0mg.kg-1 e ambos não alteram as variáveis de qualidade de água.

YAG laser peripheral iridotomy for the prevention of pigment dispersion glaucoma a prospective, randomized, controlled trial.

Science.gov (United States)

Scott, Andrew; Kotecha, Aachal; Bunce, Catey; Balidis, Miltos; Garway-Heath, David F; Miller, Michael H; Wormald, Richard

2011-03-01

To test the hypothesis that neodymium:yttrium-aluminum-garnet (Nd:YAG) laser peripheral iridotomy (LPI) significantly reduces the incidence of conversion from pigment dispersion syndrome (PDS) with ocular hypertension (OHT) to pigmentary glaucoma (PG). Prospective, randomized, controlled 3-year trial. One hundred sixteen eyes of 116 patients with PDS and OHT. Patients were assigned randomly either to Nd:YAG LPI or to a control group (no laser). The primary outcome measure was conversion to PG within 3 years, based on full-threshold visual field (VF) analysis using the Ocular Hypertension Treatment Study criteria. Secondary outcome measures were whether eyes required topical antiglaucoma medications during the study period and the time to conversion or medication. Fifty-seven patients were randomized to undergo laser treatment and 59 were randomized to no laser (controls). Age, gender, spherical equivalent refraction, and intraocular pressure at baseline were similar between groups. Outcome data were available for 105 (90%) of recruited subjects, 52 in the laser treatment group and 53 in the no laser treatment group. Patients were followed up for a median of 35.9 months (range, 10-36 months) in the laser arm and 35.9 months (range, 1-36 months) in the control arm. Eight eyes (15%) in the laser group and 3 eyes (6%) in the control group converted to glaucoma in the study period. The proportion of eyes started on medical treatment was similar in the 2 groups: 8 eyes (15%) in the laser group and 9 eyes (17%) in the control group. Survival analyses showed no evidence of any difference in time to VF progression or commencement of topical therapy between the 2 groups. Cataract extraction was performed on 1 patient in the laser group and in 1 patient in the control group during the study period (laser eye at 18 months; control eye at 34 months). This study suggests that there was no benefit of Nd:YAG LPI in preventing progression from PDS with OHT to PG within 3 years of

Development of control and data processing system for CO2 laser interferometer

International Nuclear Information System (INIS)

Chiba, Shinichi; Kawano, Yasunori; Tsuchiya, Katsuhiko; Inoue, Akira

2001-11-01

CO 2 laser interferometer diagnostic has been operating to measure the central electron density in JT-60U plasmas. We have developed a control and data processing system for the CO 2 laser interferometer with flexible functions of data acquisition, data processing and data transfer in accordance with the sequence of JT-60U discharges. This system is mainly composed of two UNIX workstations and CAMAC clusters, in which the high reliability was obtained by sharing the data process functions to the each workstations. Consequently, the control and data processing system becomes to be able to provide electron density data immediately after a JT-60U discharge, routinely. The realtime feedback control of electron density in JT-60U also becomes to be available by using a reference density signal from the CO 2 laser interferometer. (author)

Late pest control in determinate tomato cultivars Controle de pragas tardias em cultivares de tomateiro de crescimento determinado

Directory of Open Access Journals (Sweden)

Arlindo Leal Boiça Júnior

2007-12-01

Full Text Available The usage of insecticidal plants and others insect resistant varieties can be strong allies to the Integrated Pest Management (IPM, being able to reduce the number of insecticides applications and to minimize its effect to the man and the environment.The following control techniques were compared in field conditions, investigating the late pest control of two determinate tomato cultivars: a Conventional - sprayings of metamidophos, buprofezin, acephate, cipermetrin, abamectin, permetrin, teflubenzuron and lufenuron, applied every three to six days; b IPM - action threshold of each pest to the spraying of imidacloprid, triflumuron, lufenuron and abamectin; c IPM - Azadirachta indica (neem - Action threshold of each pest to the spraying of the nim oil (1.2% of azadirachtin at a concentration of 0.5%. The IPM and IPM - Neem control techniques were efficient controlling the late pest of the tomato cultivar, not differing from the conventional treatment that presented the lowest levels of infestation. The conventional control technique, IPM and IPM-neem promoted bigger tomato production with increasements of up to 74%. The number of sprayings was reduced up to 77% with the IPM and IPM - neem techniques, when compared to the conventional method. The neem product may be a promising alternative to the late pest control in the tomato field that adjusts to the IPM.O uso de plantas inseticidas e de variedades pode ser forte aliado ao Manejo Integrado de Pragas (MIP, podendo reduzir o número de aplicações de inseticidas e minimizar seus efeitos ao homem e ao meio ambiente. Em condições de campo, visando o controle de pragas tardias do tomateiro em duas cultivares de crescimento determinado, compararam-se as seguintes táticas de controle: a Convencional - pulverizações com os produtos metamidofós, buprofezin, acefato, cipermetrina, abamectina, permetrina, teflubenzuron e lufenuron, aplicados em intervalos de três a seis dias; b MIP - nível de a

Two-pulse laser control of bond-selective fragmentation

DEFF Research Database (Denmark)

Amstrup, Bjarne; Henriksen, Niels Engholm

1996-01-01

We elaborate on a two-pulse (pump-pump) laser control scheme for selective bond-breaking in molecules [Amstrup and Henriksen, J. Chem. Phys. 97, 8285 (1992)]. We show, in particular, that with this scheme one can overcome the obstacle of intramolecular vibrational relaxation. As an example, we...... consider an ozone molecule with isotopic substitution, that is, (OOO)-O-16-O-16-O-18. It is shown that asymmetric bond stretching can be created in simple (intense) laser fields. We predict that an alternating high selectivity between the channels O-16+(OO)-O-16-O-18 and (OO)-O-16-O-16+ O-18 can...

Basic mechanisms in the laser control of non-Markovian dynamics

Science.gov (United States)

Puthumpally-Joseph, R.; Mangaud, E.; Chevet, V.; Desouter-Lecomte, M.; Sugny, D.; Atabek, O.

2018-03-01

Referring to a Fano-type model qualitative analogy we develop a comprehensive basic mechanism for the laser control of the non-Markovian bath response and fully implement it in a realistic control scheme, in strongly coupled open quantum systems. Converged hierarchical equations of motion are worked out to numerically solve the master equation of a spin-boson Hamiltonian to reach the reduced electronic density matrix of a heterojunction in the presence of strong terahertz laser pulses. Robust and efficient control is achieved increasing by a factor of 2 the non-Markovianity measured by the time evolution of the volume of accessible states. The consequences of such fields on the central system populations and coherence are examined, putting the emphasis on the relation between the increase of non-Markovianity and the slowing down of decoherence processes.

Development of real-time monitoring and control in COIL laser cutting for joint R and D between Korea and U.S

Energy Technology Data Exchange (ETDEWEB)

Chung, Chin Man; Kim, Cheol Jung; Kim, Min Suk; Baik, Sung Hoon; Kwon, Sung Ok; Park, Sun Kyu

2000-12-01

The laser monitoring and control technique investigated to experiment for cutting kerf width and result of laser cutting for D and D of nuclear facility. The demands for this laser monitoring and control technique were applied to process control in laser cutting and to fabricate monitoring and control system, focusing lens assembly. This system can had a advantage to monitor and control the laser cutting on real time. KAERI investigated the COIL laser and monitored 2 kW laser power.

Development of real-time monitoring and control in COIL laser cutting for joint R and D between Korea and U.S

International Nuclear Information System (INIS)

Chung, Chin Man; Kim, Cheol Jung; Kim, Min Suk; Baik, Sung Hoon; Kwon, Sung Ok; Park, Sun Kyu

2000-12-01

The laser monitoring and control technique investigated to experiment for cutting kerf width and result of laser cutting for D and D of nuclear facility. The demands for this laser monitoring and control technique were applied to process control in laser cutting and to fabricate monitoring and control system, focusing lens assembly. This system can had a advantage to monitor and control the laser cutting on real time. KAERI investigated the COIL laser and monitored 2 kW laser power

Closed Loop Control of Penetration Depth during CO₂ Laser Lap Welding Processes

Directory of Open Access Journals (Sweden)

Antonio Ancona

2012-08-01

Full Text Available In this paper we describe a novel spectroscopic closed loop control system capable of stabilizing the penetration depth during laser welding processes by controlling the laser power. Our novel approach is to analyze the optical emission from the laser generated plasma plume above the keyhole, to calculate its electron temperature as a process-monitoring signal. Laser power has been controlled by using a quantitative relationship between the penetration depth and the plasma electron temperature. The sensor is able to correlate in real time the difference between the measured electron temperature and its reference value for the requested penetration depth. Accordingly the closed loop system adjusts the power, thus maintaining the penetration depth.

Development of the medical apparatus for Doppler-controlled treatment of hemorrhoids using laser coagulation

Directory of Open Access Journals (Sweden)

Nikolay A. Gryaznov

2017-12-01

Full Text Available In the article authors present the concept of the surgical manipulator delivering laser radiation to the target area. For the implementation of Doppler-controlled treatment of hemorrhoids by laser coagulation, an important circumstance is the necessity to realize by means of the dopplerograph the possibility of controlling the efficiency of coagulation of the pathological vessel immediately after the impact, which will create the prerequisites for the formation of a program cycle with the inclusion of control elements by feedback. In this regard, the structure of the laser medical apparatus is developed, which allows determining the location, size and flow of arterial and venous vessels, performing laser coagulation of pathologically damaged sites under constant Doppler control. The developed adaptive power management system includes several functional units for the processing of the data from ultrasound scanner and the Doppler. Medical apparatus for minimally invasive treatment of hemorrhoids based on the laser coagulator and ultrasound Doppler will allow performing surgeries in automated and half-automated modes. The suggested medical apparatus helps to determine pathological vessels, choose the required radiation mode and provides vessel obliteration. Successful realization of constructive combination of real-time diagnostics and surgical manipulation with a laser can result in a unique minimally invasive solution to treat hemorrhoids that currently doesn’t have analogues.

Four Novel Cellulose Synthase (CESA Genes from <em>Birch> (<em>Betula platyphylla em>Suk. Involved in Primary and Secondary Cell Wall Biosynthesis

Full Text Available Cellulose synthase (CESA, which is an essential catalyst for the generation of plant cell wall biomass, is mainly encoded by the <em>CesA> gene family that contains ten or more members. In this study; four full-length cDNAs encoding CESA were isolated from<em> Betula platyphyllaem> Suk., which is an important timber species, using RT-PCR combined with the RACE method and were named as <em>BplCesA3em>, <em>−4em>,> −7 em>and> −8em>. These deduced CESAs contained the same typical domains and regions as their <em>Arabidopsis> homologs. The cDNA lengths differed among these four genes, as did the locations of the various protein domains inferred from the deduced amino acid sequences, which shared amino acid sequence identities ranging from only 63.8% to 70.5%. Real-time RT-PCR showed that all four <em>BplCesAs> were expressed at different levels in diverse tissues. Results indicated that BplCESA8 might be involved in secondary cell wall biosynthesis and floral development. BplCESA3 appeared in a unique expression pattern and was possibly involved in primary cell wall biosynthesis and seed development; it might also be related to the homogalacturonan synthesis. BplCESA7 and BplCESA4 may be related to the formation of a cellulose synthase complex and participate mainly in secondary cell wall biosynthesis. The extremely low expression abundance of the four BplCESAs in mature pollen suggested very little involvement of them in mature pollen formation in <em>Betula>. The distinct expression pattern of the four <em>BplCesAs> suggested they might participate in developments of various tissues and that they are possibly controlled by distinct mechanisms in <em>Betula.>