[1]红外动目标识别跟踪系统的dsp+fpga实现




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Laser Application


206

Author(s): Tamura, J (Tamura, Jun); Okamura, M (Okamura, Masahiro); Kanesue, T (Kanesue, Takeshi)

Title: Application of cryotarget to laser ion source - art. no. 02B101

Source: REVIEW OF SCIENTIFIC INSTRUMENTS, 79 (2): B2101-B2101 Part 2 FEB 2008

Abstract:

We examined laser-produced argon plasma as part of a future laser ion source. Rare gases, which are in gas state at room temperature, need to be cooled to solid targets for laser irradiation. We generated solid Ar targets in a similar way used for neon. By irradiating the solid Ar with a neodymium doped yttrium aluminum garnet laser, we could generate Ar ions with a charge stage up to 8+ with a good stability. The feature of generated Ar plasma using this method is similar to the Ne case. The ion current density reached about 1.6 mA/cm(2) at 2.3 m from the target. This method would be applicable for a laser ion source. (c) 2008 American Institute of Physics.


Addresses: Tokyo Inst Technol, Dept Energy Sci, Midori Ku, Yokohama, Kanagawa 2268502, Japan

RIKEN, Radiat Lab, Wako, Saitama 3510198, Japan

Brookhaven Natl Lab, Collider Acceleerator Dept, Upton, NY 11973 USA

Kyushu Univ, Dept Appl quantum Phys & Nucl Engn, Nishi Ku, Fukuoka 8190395, Japan

Reprint Address: TAMURA, J, TOKYO INST TECHNOL, DEPT ENERGY SCI, MIDORI KU, 4259 NAGATSITA CHO, YOKOHAMA, KANAGAWA 2268502, JAPAN

Author's E-mail: jtamura@riken.jp

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207


Author(s): Klemm, AJ (Klemm, Agnieszka J.); Sanjeevan, P (Sanjeevan, Poologanathan)

Title: Application of laser speckle analysis for the assessment of cementitious surfaces subjected to laser cleaning

Source: APPLIED SURFACE SCIENCE, 254 (9): 2642-2649 FEB 28 2008

Abstract:

This paper focuses on the application of laser speckle technique for the assessment of the effectiveness of laser cleaning of cementitious surfaces. Laser speckle-based methods are non-contact, highly resolving techniques for the measurement of displacement, rotation, and strain of an illuminated area on a rough surface. Since the intensity of reflected light depends on the geometrical microstructure and colour of the samples, any alterations of the surface result in different speckle images. Analysis of speckle images presented here is based on the analysis of the distribution of intensity of reflected light obtained in a selected plane, and analysis of statistical parameters describing such distribution (skewness and kurtosis). A wide range of laser-cleaned mortar samples with different geometrical microstructure and moisture content has been subjected to the assessment by He-Ne laser. Laser speckle method has been successfully used to identify the effectiveness of the laser cleaning process with respect to different surface conditions. It appears that the changes in kurtosis and skewness should be mainly associated with the alterations of geometrical microstructure. Whereas, mean light intensity seemed to depend predominantly on the mortar's absorption characteristics (colour). (C) 2007 Elsevier B. V. All rights reserved.
Addresses: Glasgow Caledonian Univ, Sch Built & Nat Environm, Glasgow G4 0BA, Lanark, Scotland

Reprint Address: KLEMM, AJ, GLASGOW CALEDONIAN UNIV, SCH BUILT & NAT ENVIRONM, 70 COWCADDENS RD, GLASGOW G4 0BA, LANARK, SCOTLAND

Author's E-mail: a.klemm@gcal.ac.uk

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208

Author(s): Ritz, JP (Ritz, Joerg P.); Lehmann, KS (Lehmann, Kai S.); Mols, A (Mols, Anke); Frericks, B (Frericks, Bernd); Knappe, V (Knappe, Verena); Buhr, HJ (Buhr, Heinz J.); Holmer, C (Holmer, Christoph)



Title: Laser-induced thermotherapy for lung tissue-evaluation of two different internally cooled application systems for clinical use

Source: LASERS IN MEDICAL SCIENCE, 23 (2): 195-202 APR 2008

Abstract:

Thermal ablation techniques like radiofrequency or laser-induced thermotherapy (LITT) are increasingly used to treat tumors of parenchymatous organs. Minimal access, parenchymal preservation, and a low complication rate render them suitable for pulmonary tumors as well. Their successful clinical application depends on the induction of sufficiently large lesions and a knowledge of the energy parameters required for complete thermal ablation. The aim of this study was to establish a dose-response relationship for a percutaneous and an intraoperative system for LITT of lung tissue. Thermal lesions were induced in healthy porcine lungs using an Nd:YAG laser (1,064 nm). LITT was performed with a percutaneous application system in group I (n=18) and an intraoperative application system in group II (n=90). Laser energy was applied for 600-1,200 s in a power range of 20-32 W (12,000-38,400 J). The lesions were longitudinally and transversally measured, and the volume was calculated after the intervention. Furthermore, an open application system was used to perform LITT under in vivo conditions during lung perfusion and ventilation in domestic pigs. Lesion volumes in both groups showed a plateau-like curve when the laser power increased from an initial level of 25 W. With the percutaneous puncture system (group I), the application of 28 W (16,800 J) for 10 min generated the largest lesions with a volume of 12.54 +/- 1.33 cm(3), an axial diameter of 39.33 +/- 2.52 mm, and a diametrical diameter of 24.67 +/- 1.15 mm. A longer application time was not possible due to thermal instability of the applicator. Moreover, group I started developing extensive carbonizations at a laser power of 22 W (13,200 J). The intraoperative application system (group II) achieved the largest lesion volumes of 11.03 +/- 2.54 cm(3) with diameters of 34.6 +/- 4.22 mm (axial) and 25.6 +/- 2.51 mm (diametrical) by an exposure time of 20 min and a power of 32 W (38,400 J). Here extensive carbonizations only started to occur at 28 W (33,600 J). Under in vivo conditions, all pigs tolerated the LITT procedure well without complications. Besides a typical cooling effect in the vicinity of blood vessels, the thermal lesions were about three times smaller than the ex vivo lesions. Both the percutaneous and the open LITT application system induced reproducible, clinically relevant lung lesions. The percutaneous puncture set generated large relevant lesions, although its usability is limited by its restricted capacity and high carbonization risk. It is suitable for powers up to 22 W. The intraoperative application system allows higher energy exposure to induce larger lesion volumes. This study elucidates the dose-effect relation of two clinically relevant puncture sets.


Addresses: Charite Univ Med Berlin, Dept Gen Vasc & Thorac Surg, D-122000 Berlin, Germany

Charite Univ Med Berlin, Dept Radiol & Nucl Med, Berlin, Germany

Laser & Med Technol Corp Berlin, Berlin, Germany

Reprint Address: HOLMER, C, CHARITE UNIV MED BERLIN, DEPT GEN VASC & THORAC SURG, CAMPUS BENJAMIN FRANKLIN,HINDERNBURGDAMM 30, D-122000 BERLIN, GERMANY

Author's E-mail: christoph.holmer@charite.de

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209

Author(s): Fenoul, F (Fenoul, F.); Le Denmat, M (Le Denmat, M.); Hamdi, F (Hamdi, F.); Cuvelier, G (Cuvelier, G.); Michon, C (Michon, C.)



Title: Technical note: Confocal scanning laser microscopy and quantitative image analysis: Application to cream cheese microstructure investigation

Source: JOURNAL OF DAIRY SCIENCE, 91 (4): 1325-1333 APR 2008

Abstract:

The naked eye observation of cream cheese confocal scanning laser microscopy images only provides qualitative information about its microstructure. Because those products are dense dairy gels, confocal scanning laser microscopy images of 2 different cream cheeses may appear close. Quantitative image analysis is then necessary to compensate for human eye deficiency (e. g., lack of precision, subjectivity). Two kinds of quantitative image analysis were performed in this study: high-order statistical methods and grayscale mathematical morphology. They were applied to study the microstructure of 3 different cream cheeses (same manufacturing process, same dry matter content, but different fat and protein contents). Advantages and drawbacks of both methods are reviewed. The way they may be used to describe cream cheese microstructure is also presented.


Addresses: AgroParis Tech, UMR SCALE 1211, ENSIA, INRA,CNAM, F-91744 Massy, France

Dept Rech Appl, Grp Bel, F-41102 Vendome, France

Reprint Address: MICHON, C, AGROPARIS TECH, UMR SCALE 1211, ENSIA, INRA,CNAM, 1 AVE OLYMPIADES, F-91744 MASSY, FRANCE

Author's E-mail: Camille.Michon@agroparistech.fr

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210


Author(s): Maffi, S (Maffi, S.); Cignoli, F (Cignoli, F.); Bellomunno, C (Bellomunno, C.); Iullis, S (De Iullis, S.); Zizak, G (Zizak, G.)

Title: Spectral effects in laser induced incandescence application to flame-made titania nanoparticles

Source: SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY, 63 (2): 202-209 FEB 2008

Abstract:

Particle size is a crucial parameter in nanopowder use and production. A method to obtain information about this during the particle synthesis would be very valuable in order to optimize the process. In the field of nanoparticles flame synthesis, an extension of the techniques used in soot diagnostics sounds rather obvious, but it is far from being easily accomplished. In this paper investigations on the application of the laser induced incandescence to TiO2 nanoparticles in a flame reactor are reported. The work basically concerns the effects of laser fluence on the spectral structure of the laser-excited radiation emitted from the particles. It will be shown that in many cases such a radiation cannot be plainly assumed as an incandescence signal. Measurements of the signal time decay are reported and interpreted in the light of the spectral indications. Finally, the dependence of such a time decay on the particle size is experimentally demonstrated. (C) 2007 Elsevier B.V. All rights reserved.
Addresses: CNR, IENI, I-20125 Milan, Italy

Reprint Address: CIGNOLI, F, CNR, IENI, VIA R COZZI 53, I-20125 MILAN, ITALY

Author's E-mail: maffi@ieni.cnr.it

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211

Author(s): Yasuda, A (Yasuda, Arata); Suto, K (Suto, Ken); Takahashi, Y (Takahashi, Yatsuhlro); Kato, Y (Kato, Yoshikazu); Oyama, Y (Oyama, Yutaka); Nishzawa, JI (Nishzawa, Jun-ich)



Title: Liquid-phase epitaxy of In-doped PbTe for the application of mid-infrared semiconductor laser

Source: JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS, 69 (2-3): 727-729 FEB-MAR 2008

Abstract:

Indium-doped PbTe epitaxial layers and pn homojunction diodes were grown on PbTe substrate using the temperature-difference method under controlled vapor pressure (TDM-CVP) liquid-phase epitaxy (LPE). The activation ratio of indium donor in the PbTe epitaxial layer was as high as 80%, and we achieved high electron concentrations UP to n(D) = 5 x 10(19)cm(-3). In view of the enhanced electron mobility, it is shown that the optimum Te vapor pressure for an In-doped PbTe epitaxial layer is about 2 x 10(-5) Torr at 470 degrees C, which agrees well with the results for undoped and heavily Bi-doped PbTe epitaxial layers. In-doped n(+)-PbTe layer was successfully applied for the fabrication of broad contact pn junction lasers and excellent lasing emissions were achieved, characteristics as compared to Bi-doped and -undoped cladding layers. The threshold current for a broad area diode is 200 A/cm(2) at 15 K and 2.7 kA/cm(2) at 77 K. (c) 2007 Elsevier Ltd. All rights reserved.


Addresses: Tohoku Univ, Grad Sch Engn, Dept MS&E, Sendai, Miyagi 9808579, Japan

Semicond Res Inst Semicond Res Fdn, Sendai, Miyagi 9808579, Japan

Reprint Address: OYAMA, Y, TOHOKU UNIV, GRAD SCH ENGN, DEPT MS&E, ARAMAKI AZA AOBA 6-6-11-1021, SENDAI, MIYAGI 9808579, JAPAN

Author's E-mail: a5ttii5308@stu.material.tohoku.ac.jp

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212


Author(s): Orth, K (Orth, K.); Boelke, E (Boelke, E.); Steinbach, G (Steinbach, G.); Steiner, R (Steiner, R.); Russ, D (Russ, D.)

Title: In vivo results for interstitial laser application in thyroid gland

Source: EUROPEAN JOURNAL OF MEDICAL RESEARCH, 13 (2): 63-67 FEB 25 2008

Abstract:

Objective: Aim of this study was to evaluate the potential of denaturation of hormone active tissue in the thyroid gland by laser induced interstitial thermotherapy (LITT) as a treatment of autonomous hyperthyroidism.

Materials and Methods: An interstitial thyroid laser application (Nd:YAG 1064nm, 5W, 2min) was performed in 5 pigs. During laser application, the laryngeal recurrent nerve was controlled electro-physiologically. Post-operatively, TSH, total T-3 (TT3) and free T-4 (FT4) were measured regularly. After a follow-up period of up to 6 weeks, pigs were sacrificed and the thyroid glands were evaluated histological.

Results: A malfunction of the nerve due to laser treatment was not detected. During the first postoperative week there was a decrease of both FT4 and TSH whereas TT3 showed an extreme decline of its plasma levels reaching nearly the detection limit. All values showed a recovery to their initial levels during an interval of 10 days and than increased to levels sometimes higher than baseline. The coagulation zones were demarcated clearly towards normal tissue with increasing fibrosis of the treated areas.

Conclusion: Interstitial thyroid ablation using a Nd:YAG laser is a minimal invasive, safe and effective procedure. Further evaluation including long term follow-up in humans is needed to confirm these results.


Addresses: Klinikum Emden, Dept Gen Surg, D-26721 Emden, Germany

Univ Dusseldorf, Dept Radiooncol, D-4000 Dusseldorf, Germany

Univ Ulm, Dept Clin Chem, D-89069 Ulm, Germany

Univ Ulm, Inst Lasertechnol Med & Messtech, D-89069 Ulm, Germany

Reprint Address: ORTH, K, KLINIKUM EMDEN, DEPT GEN SURG, BOLARDUSSTR 20, D-26721 EMDEN, GERMANY

Author's E-mail: k.orth@klinikum-emden.de

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213


Author(s): Bitter, K (Bitter, Kerstin); Noetzel, J (Noetzel, Joern); Volk, C (Volk, Claudia); Neumann, K (Neumann, Konrad); Kielbassa, AM (Kielbassa, Andrej Michael)

Title: Bond strength of fiber posts after the application of erbium : yttrium-aluminum-garnet laser treatment and gaseous ozone to the root canal

Source: JOURNAL OF ENDODONTICS, 34 (3): 306-309 MAR 2008

Abstract:

The aim of the present study was to investigate the effects of antibacterial agents (erbium:yttrium-aluminum-garnet [Er:YAG] laser or gaseous ozone) intended to disinfect root canals on bond strengths of fiber posts compared with canals that were finally irrigated using chlorhexidine (CHX). One hundred forty-four human anterior teeth were divided into three groups (n = 48); root canal instrumentation was performed, and antimicrobial pretreatment was conducted as follows: control group: CHX, group 2: Er:YAG laser, and group 3: gaseous ozone. In all groups, fiber posts were inserted using Panavia F 2.0 (Kuraray, Osaka, Japan), Variolink II (lvoclar Vivadent, Schaan, Liechtenstein), RelyX Unicem (3M Espe; Seefeld, Germany), or Ketac Cem (3M Espe) (n = 12 each). Push-out bond strengths to root canal dentin were affected by the type of luting agent but not by the antimicrobial pretreatment regimen. However, significant interactions between the luting agent and pretreatment could be observed, and adhesion of the self-adhesive resin cement RelyX Unicem was significantly reduced after using gaseous ozone.
Addresses: Charite Univ Med Berlin, Univ Sch Dent Med, Dept Operat Dent & Peridontol, Charite Ctr 3, D-13353 Berlin, Germany

Charite Univ Med Berlin, Inst Biometry & Clin Epidemiol, Charite Ctr 4, D-13353 Berlin, Germany

Reprint Address: BITTER, K, CHARITE UNIV MED BERLIN, ABT ZAHNERHALTUNGSKUNDE & PARADONTOL, CHARITE CTR ZAHN MUND & KIEFERHEIKUNDE, ASSMANNSHAUSER STR 4-6, D-14197 BERLIN, GERMANY

Author's E-mail: kerstin.bitter@charite.de

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214


Author(s): Fang, RR (Fang, Ranran); Zhang, DM (Zhang, Duanming); Li, ZH (Li, Zhihua); Yang, FX (Yang, Fengxia); Li, L (Li, Li); Tan, XY (Tan, Xinyu); Sun, M (Sun, Min)

Title: Improved thermal model and its application in UV high-power pulsed laser ablation of metal target

Source: SOLID STATE COMMUNICATIONS, 145 (11-12): 556-560 MAR 2008

Abstract:

An improved thermal model describing UV high-power nanosecond laser ablation of metal target is presented. The vaporization effect, the plasma shielding effect, as well as the absorption coefficient and absorptivity dependence of temperature are considered in this model. Take iron target as an example, the numerical solutions are obtained from the heat flow equations (before and after melting) using a finite difference method. The space and time dependence of temperature of the target, the time dependence of temperature at two different positions for a certain laser fluence, and the ablation rate as a function of laser fluence are also presented. The numerical results that agreed well with the experimental data are much better than the one without, which indicates that the above two effects and the temperature dependence of absorption coefficient and absorptivity in UV high-power laser ablation of metal target should not be neglected. We hope the present model will be useful for further experimental investigation of metal thin films prepared by pulsed laser deposition. (C) 2008 Elsevier Ltd. All rights reserved.
Addresses: Huazhong Univ Sci & Technol, Dept Phys, Wuhan 430074, Peoples R China

Reprint Address: ZHANG, DM, HUAZHONG UNIV SCI & TECHNOL, DEPT PHYS, WUHAN 430074, PEOPLES R CHINA

Author's E-mail: ranranfang2@gmail.com

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215

Author(s): van Elsen, M (van Elsen, Maarten); Al-Bender, F (Al-Bender, Farid); Kruth, JP (Kruth, Jean-Pierre)



Title: Application of dimensional analysis to selective laser melting

Source: RAPID PROTOTYPING JOURNAL, 14 (1): 15-22 2008

Abstract:

Purpose - This paper aims to present a possible complete set of dimensionless parameters to describe the process of selective laser melting (SLM). This makes it possible to compare the similarity between different experiments, a sine-qua-non for a correct comparison of the results.

Design/methodology/approach - The paper describes the application of dimensional analysis to SLM. Findings - Although the idea of dimensionless numbers is far from new, it has apparently never been applied rigorously to rapid prototyping and rapid manufacturing technologies. The technique is important, since it reduces the number of factors and makes it possible to compare results of different research groups. Furthermore, some more fundamental insights about the process can be gained.

Originality/value - This work is a first step towards a manageable system to control very difficult processes.


Addresses: Katholieke Univ Leuven, Dept Mech Engn, B-3001 Heverlee, Belgium

Reprint Address: VAN ELSEN, M, KATHOLIEKE UNIV LEUVEN, DEPT MECH ENGN, B-3001 HEVERLEE, BELGIUM

Author's E-mail: VanElsen@mech.kuleuven.be

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216

Author(s): Vass, J (Vass, J.); Smid, R (Smid, R.); Randall, RB (Randall, R. B.); Sovka, P (Sovka, P.); Cristalli, C (Cristalli, C.); Torcianti, B (Torcianti, B.)



Title: Avoidance of speckle noise in laser vibrometry by the use of kurtosis ratio: Application to mechanical fault diagnostics

Source: MECHANICAL SYSTEMS AND SIGNAL PROCESSING, 22 (3): 647-671 APR 2008

Abstract:

This paper presents a statistical technique to enhance vibration signals measured by laser Doppler vibrometry (LDV). The method has been optimised for LDV signals measured on bearings of universal electric motors and applied to quality control of washing machines. Inherent problems of LDV are addressed, particularly the speckle noise occurring when rough surfaces are measured. The presence of speckle noise is detected using a new scalar indicator kurtosis ratio (KR), specifically designed to quantify the amount of random impulses generated by this noise. The KR is a ratio of the standard kurtosis and a robust estimate of kurtosis, thus indicating the outliers in the data. Since it is inefficient to reject the signals affected by the speckle noise, an algorithm for selecting an undistorted portion of a signal is proposed. The algorithm operates in the time domain and is thus fast and simple. The algorithm includes band-pass filtering and segmentation of the signal, as well as thresholding of the KR computed for each filtered signal segment. Algorithm parameters are discussed in detail and instructions for optimisation are provided. Experimental results demonstrate that speckle noise is effectively avoided in severely distorted signals, thus improving the signal-to-noise ratio (SNR) significantly. Typical faults are finally detected using squared envelope analysis. It is also shown that the KR of the band-pass filtered signal is related to the spectral kurtosis (SK). (c) 2007 Elsevier Ltd. All rights reserved.


Addresses: Czech Tech Univ Prague, Fac Elect Engn, Prague 16627, Czech Republic

Univ New S Wales, Sch Mech & Mfg Engn, Sydney, NSW 2052, Australia

Loccioni Grp, AEA SRL, I-60030 Ancona, Italy

Reprint Address: VASS, J, CZECH TECH UNIV PRAGUE, FAC ELECT ENGN, TECHN 2, PRAGUE 16627, CZECH REPUBLIC

Author's E-mail: vassj@fel.cvut.cz

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217

Author(s): Cicala, E (Cicala, E.); Soveja, A (Soveja, A.); Sallamand, P (Sallamand, P.); Grevey, D (Grevey, D.); Jouvard, JM (Jouvard, J. M.)



Title: The application of the random balance method in laser machining of metals

Source: JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, 196 (1-3): 393-401 JAN 21 2008

Abstract:

Features peculiar to laser technology offer some advantages over more traditional processes, but, like all processes, it has its limitations. This article studies the limitations of laser machining of metals, and quantifies, through an experimental design method, the influence of operating parameters on productivity and on the quality of the machined surface. Three study materials were used: an aluminium alloy, stainless steel and a titanium alloy. An initial reading of the results indicates that productivity depends mainly on the frequency of the laser pulse and that the aluminium alloy behaves differently from the other two. The quality of the machined surface, judged here by roughness, was likewise dependent on pulse frequency and, to a lesser degree, on sweep speed. Surface roughness was minimized by increasing the pulse frequency and reducing the sweep speed. The experimental results were accurately predicted by simple polynomial models. (c) 2007 Elsevier B.V. All rights reserved.


Addresses: Univ Bourgogne, IUT Le Creusot, Dept Interface & Reactiv Mat, UMR CNRS 5209,Inst Carnot Bourgogne, F-71200 Le Creusot, France

Univ Politechn Timisoara, Fac Mecan, Timisoara 300006, Romania

Reprint Address: SOVEJA, A, UNIV BOURGOGNE, IUT LE CREUSOT, DEPT INTERFACE & REACTIV MAT, UMR CNRS 5209,INST CARNOT BOURGOGNE, 12 RUE FONDERIE, F-71200 LE CREUSOT, FRANCE

Author's E-mail: adriana.soveja@u-bourgogne.fr

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218


Author(s): Gonzaga, FB (Gonzaga, Fabiano Barbieri); Pasquini, C (Pasquini, Cefio)

Title: A Complementary Metal Oxide Semiconductor sensor array based detection system for Laser Induced Breakdown Spectroscopy: Evaluation of calibration strategies and application for manganese determination in steel

Source: SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY, 63 (1): 56-63 JAN 2008

Abstract:

This paper describes a low cost detection system for Laser Induced Breakdown Spectroscopy based on a simple spectrograph employing a conventional diffraction grating and a non-intensified, non-gated, non-cooled 1024 pixel Complementary Metal Oxide Semiconductor linear sensor array covering the spectral range from about 250 to 390 rim. It was employed in conjunction with a 1064 rim, 5 ns pulse duration Nd:YAG laser source for analyzing steel samples using the integration of 300 analysis pulses (35 mJ each). That led to gains in the signal-to-noise ratio of approximately 3 and 16 for Mn and Fe peaks, respectively, in addition to gains in the emission intensities of about 5.3, both in comparison with the integration of just 50 analysis pulses. The acquired emission spectra were used for Mn determination, in the range from 0.214 to 0.608% m/m as previously determined by ICP OES, evaluating different univariate (at different discrete wavelengths) and multivariate (over different spectral ranges) calibration strategies. The best results, using a PLS calibration model in the spectral range from 292.9 to 294.5 nm (related to Mn emission peaks), had relative errors of prediction of the Mn concentrations, for samples not employed in the calibration, from 0.3 to 7.3%, which are similar to or better than those obtained for Mn determination in steel using higher cost detection systems. The successful analytical application of the new detection system demonstrated that the performance of low cost detection systems can be very good for specific applications and that its low resolution and sensitivity can be at least partially compensated by the use of chemometrics and the integration of analysis pulses. (C) 2007 Elsevier B.V. All rights reserved.
Addresses: Univ Estadual Campinas, Inst Quim, BR-13084971 Campinas, SP, Brazil

Reprint Address: GONZAGA, FB, UNIV ESTADUAL CAMPINAS, INST QUIM, CAIXA POSTAL 6154, BR-13084971 CAMPINAS, SP, BRAZIL

Author's E-mail: fbgalo@gmail.com

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219

Author(s): Sevilla, P (Sevilla, P.); Martorell, F (Martorell, F.); Libenson, C (Libenson, C.); Planell, JA (Planell, J. A.); Gil, FJ (Gil, F. J.)



Title: Laser welding of NiTi orthodontic archwires for selective force application

Source: JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE, 19 (2): 525-529 FEB 2008

Abstract:

Conventional superelastic orthodontic wires are arch-shaped, have the same mechanical properties all along their length and are used to correct the position of teeth. The disadvantage of these archwires is that there are different types of teeth in the mouth and different forces are therefore needed to rectify their position. The aim of this work was to laser weld several types of NiTi orthodontic wires that had different chemical compositions and superelastic properties, in order to adjust their properties to different parts of the mouth. Microstructural changes, transformation stresses and temperatures, variations in corrosion behaviour and ion release were studied in the welded wires.


Addresses: Univ Politecn Cataluna, ETSEIB, CREB, Dept Ciencia Mat & Ingn Metalurg, E-08028 Barcelona, Spain

Labs F Martorell, Barcelona, Spain

Clin Gala Placidia, Barcelona, Spain

Reprint Address: GIL, FJ, UNIV POLITECN CATALUNA, ETSEIB, CREB, DEPT CIENCIA MAT & INGN METALURG, AV DIAGONAL 647, E-08028 BARCELONA, SPAIN

Author's E-mail: francesc.xavier.gil@upc.edu

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220

Author(s): Grouiez, B (Grouiez, B.); Parvitte, B (Parvitte, B.); Joly, L (Joly, L.); Courtois, D (Courtois, D.); Zeninari, V (Zeninari, V.)



Title: Comparison of a quantum cascade laser used in both cw and pulsed modes. Application to the study of SO2 lines around 9 mu m

Source: APPLIED PHYSICS B-LASERS AND OPTICS, 90 (2): 177-186 FEB 2008

Abstract:

The same quantum cascade laser spectrometer working around 9 mu m was used in both continuous-wave and pulsed modes to compare their own characteristics. The laser emitting in continuous-wave mode was mainly used to study some spectroscopic parameters of SO2 ro-vibrational lines. This work demonstrates the necessity to use new calculations previously developed instead of conventional databases such as HITRAN. In addition, the same laser emitting in pulsed mode with long pulses (600 to 900 ns) was used to record SO2 spectra with the intrapulse technique. This work permits us to make comparisons about those two modes of emission for the development of future spectrometers.

Addresses: UFR Sci Exact Naturelles, CNRS, UMR, Grp Spectrometr Mol Atmospher, F-51687 Reims, France

Reprint Address: ZENINARI, V, UFR SCI EXACT NATURELLES, CNRS, UMR, GRP SPECTROMETR MOL ATMOSPHER, MOULIN HOUSSE, BP 1039, F-51687 REIMS, FRANCE

Author's E-mail: virginie.zeninari@univ-reims.fr

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