Laser techniques for local particle velocity and size measurements in flows are presented and discussed. The laser doppler anemometer utilizing the Doppler shift of light scattered on small particles in a flow for velocity measurements is the basis of the presented techniques. Furthermore phase Doppler anemometry based on the spatial properties of the Doppler shift and shadow Doppler velocimetry utilizing the shadow image of particle for size measurements are briefly discussed. Experimental results illustrating the use of the techniques are presented. These comprise particle velocity measurements in a sudden expansion liquid solid flow as well as in a model of a beater wheel mill. PDA measurements of the size distribution of droplets produced by a nebulizer ar also presented.
{"title":"Recent developments in nonintrusive measuring techniques for particle velocity and size measurements","authors":"T. Achimastos, M. Founti, T. Panidis","doi":"10.1117/12.316600","DOIUrl":"https://doi.org/10.1117/12.316600","url":null,"abstract":"Laser techniques for local particle velocity and size measurements in flows are presented and discussed. The laser doppler anemometer utilizing the Doppler shift of light scattered on small particles in a flow for velocity measurements is the basis of the presented techniques. Furthermore phase Doppler anemometry based on the spatial properties of the Doppler shift and shadow Doppler velocimetry utilizing the shadow image of particle for size measurements are briefly discussed. Experimental results illustrating the use of the techniques are presented. These comprise particle velocity measurements in a sudden expansion liquid solid flow as well as in a model of a beater wheel mill. PDA measurements of the size distribution of droplets produced by a nebulizer ar also presented.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115226916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lasers have many industrial applications, ranging from very high precision mechanics, to industrial marking for functional and/or decorative purposes. In this paper the author, on previous specific experience deals with the extension of the equipment capability. The goal is reached with an easy marking process modification and a high performance software development.
{"title":"Geometrical correction method for CAD/CAM laser-marking applications","authors":"A. Carrino, G. Paduano, A. Palma, A. Quaglianelli","doi":"10.1117/12.316617","DOIUrl":"https://doi.org/10.1117/12.316617","url":null,"abstract":"Lasers have many industrial applications, ranging from very high precision mechanics, to industrial marking for functional and/or decorative purposes. In this paper the author, on previous specific experience deals with the extension of the equipment capability. The goal is reached with an easy marking process modification and a high performance software development.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"224 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129297753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Panagopoulos, G. Tsobanidou, P. E. Agathocleous, A. Manousaki
Nickel coated mild steel specimens were irradiate with a high power excimer laser. Laser induced surface structures were observed by means of microscopy. The appearance of nickel oxides on the specimens surface was observed on x- rays diffraction spectra. The surface roughness was noted to be dependent on the lasing conditions. Energy dispersive x- rays analysis showed that iron atoms diffused into the nickel coating and nickel atoms diffused into the steel substrate.
{"title":"Excimer laser treatment of nickel-coated mild steel","authors":"C. Panagopoulos, G. Tsobanidou, P. E. Agathocleous, A. Manousaki","doi":"10.1117/12.316605","DOIUrl":"https://doi.org/10.1117/12.316605","url":null,"abstract":"Nickel coated mild steel specimens were irradiate with a high power excimer laser. Laser induced surface structures were observed by means of microscopy. The appearance of nickel oxides on the specimens surface was observed on x- rays diffraction spectra. The surface roughness was noted to be dependent on the lasing conditions. Energy dispersive x- rays analysis showed that iron atoms diffused into the nickel coating and nickel atoms diffused into the steel substrate.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126899051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Wendt, K. Blaum, B. Bushaw, P. Mueller, W. Nortershauser, A. Schmitt, N. Trautmann, B. Wiche
A refined diode laser based resonance ionization mass spectrometer for highly selective ultratrace analysis is presented, which combines coherent narrow-band multistep resonance excitation and ionization with a compact quadruple mass spectrometer. The widespread analytical potential and applicability of this system is demonstrated in the determination of calcium trace and ultratrace isotopes for cosmochemical studies, medical investigations and radiodating. For a detailed theoretical understanding of the coherent high resolution multistep excitation process a description in the density matrix formalism was worked out. For calcium optical isotopic selectivities of more than 1010 and efficiencies of up to 5 percent are predicted, which compare well to the analytical requirements for 41Ca-determination, which reach a maximum isotopic selectivity of more than 1015. Experimentally different ionization schemes, including single-, double- and triple- resonance excitation of calcium, have been investigated. The first-step excitation at 422,7 nm requires frequency doubling of a diode laser, while second and third steps are directly excited with extended cavity diode lasers. Analytical measurements cover meteorite and blood samples and demonstrate the feasibility of the predicted specifications. Continuing work will focus towards the application of the full triple-resonance scheme for ultra low-level measurements of 41Ca and shall establish resonance ionization mass spectrometry as a competitive technology to accelerator mass spectrometry.
{"title":"Ultratrace analysis of calcium with high isotopic selectivity by diode laser resonance ionization mass spectrometry","authors":"K. Wendt, K. Blaum, B. Bushaw, P. Mueller, W. Nortershauser, A. Schmitt, N. Trautmann, B. Wiche","doi":"10.1117/12.316589","DOIUrl":"https://doi.org/10.1117/12.316589","url":null,"abstract":"A refined diode laser based resonance ionization mass spectrometer for highly selective ultratrace analysis is presented, which combines coherent narrow-band multistep resonance excitation and ionization with a compact quadruple mass spectrometer. The widespread analytical potential and applicability of this system is demonstrated in the determination of calcium trace and ultratrace isotopes for cosmochemical studies, medical investigations and radiodating. For a detailed theoretical understanding of the coherent high resolution multistep excitation process a description in the density matrix formalism was worked out. For calcium optical isotopic selectivities of more than 1010 and efficiencies of up to 5 percent are predicted, which compare well to the analytical requirements for 41Ca-determination, which reach a maximum isotopic selectivity of more than 1015. Experimentally different ionization schemes, including single-, double- and triple- resonance excitation of calcium, have been investigated. The first-step excitation at 422,7 nm requires frequency doubling of a diode laser, while second and third steps are directly excited with extended cavity diode lasers. Analytical measurements cover meteorite and blood samples and demonstrate the feasibility of the predicted specifications. Continuing work will focus towards the application of the full triple-resonance scheme for ultra low-level measurements of 41Ca and shall establish resonance ionization mass spectrometry as a competitive technology to accelerator mass spectrometry.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129407903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A successful enhancement of sticking of PTFE is demonstrated using ArF excimer laser irradiation in the presence of novel photoreagents. The applied laser fluence was very low at the sample - photoreagent liquid interface compared to the energy density applied in earlier investigations. After the treatment the PTFE films were glued by epoxy resin. It was found that at low doses the tensile strength of the sticking increased rapidly with the UV pulse number and the reached a saturation value, which was 6.66 MPa for triethylamine, 5.56 MPa in the case of 1,2-diaminoethane and 4.64 MPa for triethylene-tetramine. These are around two hundred times higher than the value of the untreated surface. It was found that this procedure makes the metallization and painting of PTFE surface also possible. A photoinduced electron transfer mechanism was suggested to describe the photoreaction, which is responsible for the increase of adhesion features on PTFE surface.
{"title":"High-tensile strength sticking induced by ArF excimer laser surface treatment of poly(tetrafluoroethylene)","authors":"B. Hopp, K. Revesz, Z. Bor","doi":"10.1117/12.316623","DOIUrl":"https://doi.org/10.1117/12.316623","url":null,"abstract":"A successful enhancement of sticking of PTFE is demonstrated using ArF excimer laser irradiation in the presence of novel photoreagents. The applied laser fluence was very low at the sample - photoreagent liquid interface compared to the energy density applied in earlier investigations. After the treatment the PTFE films were glued by epoxy resin. It was found that at low doses the tensile strength of the sticking increased rapidly with the UV pulse number and the reached a saturation value, which was 6.66 MPa for triethylamine, 5.56 MPa in the case of 1,2-diaminoethane and 4.64 MPa for triethylene-tetramine. These are around two hundred times higher than the value of the untreated surface. It was found that this procedure makes the metallization and painting of PTFE surface also possible. A photoinduced electron transfer mechanism was suggested to describe the photoreaction, which is responsible for the increase of adhesion features on PTFE surface.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127386482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The wide use of laser pointers must be compatible to the national and international 'avoid hazards' rules. Thus the owners and users of these lasers must follow all the safety standards, in order to avoid an ocular over-exposure to themselves or to the near audience persons. Many users are not laser specialists and do not know all the safety procedures or the exposure limits. For an average user the meaning of the warning label is not so clear, he may understand the wavelength and the output power, but what is the class of the laser. The word 'danger' in the pointer's label is clear, but for some young persons is the motive to use the pointer as the optical 'weapon' against the eyes of other people. The subject of our report is the identification of some hazard situations on the pointers use, starting with the basic hazard analysis, followed by application of optical metrology with calculations and measurements of the exposure levels and ending with the comparison to the maximum permissible exposure limits, in order to make clear that in some applications the hazard is a strong possibility. Thus a specialist consultant may take the advantage from our results and explain to the users that the laser pointer must be used with all the safety procedures and with the necessary care.
{"title":"Use of laser pointers and the related hazards","authors":"S. Tsitomeneas, A. Carabelas","doi":"10.1117/12.316637","DOIUrl":"https://doi.org/10.1117/12.316637","url":null,"abstract":"The wide use of laser pointers must be compatible to the national and international 'avoid hazards' rules. Thus the owners and users of these lasers must follow all the safety standards, in order to avoid an ocular over-exposure to themselves or to the near audience persons. Many users are not laser specialists and do not know all the safety procedures or the exposure limits. For an average user the meaning of the warning label is not so clear, he may understand the wavelength and the output power, but what is the class of the laser. The word 'danger' in the pointer's label is clear, but for some young persons is the motive to use the pointer as the optical 'weapon' against the eyes of other people. The subject of our report is the identification of some hazard situations on the pointers use, starting with the basic hazard analysis, followed by application of optical metrology with calculations and measurements of the exposure levels and ending with the comparison to the maximum permissible exposure limits, in order to make clear that in some applications the hazard is a strong possibility. Thus a specialist consultant may take the advantage from our results and explain to the users that the laser pointer must be used with all the safety procedures and with the necessary care.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128342854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Palchetti, E. Giorgetti, D. Grando, S. Sottini, G. Banfi
Great hopes currently lie in new all-optical switching devices based on polymer film waveguides. Here, the design of a novel all-optical waveguide frequency converter is reported, the research activity for which was carried out within the framework of the Italian Project on Telecommunications.
{"title":"Design of a frequency converter based on a hybrid glass/polymer waveguide device","authors":"L. Palchetti, E. Giorgetti, D. Grando, S. Sottini, G. Banfi","doi":"10.1117/12.316560","DOIUrl":"https://doi.org/10.1117/12.316560","url":null,"abstract":"Great hopes currently lie in new all-optical switching devices based on polymer film waveguides. Here, the design of a novel all-optical waveguide frequency converter is reported, the research activity for which was carried out within the framework of the Italian Project on Telecommunications.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130558345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Hopp, A. Nógrádi, K. Revesz, Z. Bor, L. Kolozsvári
The earlier investigations showed that the corneal haze can be due to the scattering effect of the excimer laser induced surface structure. In this paper a comparative study is presented regarding the development of these. Several human corneas were irradiated by an ArF excimer laser. The applied fluence was 193 mJ/cm2. The developed surface structures after each excimer pulse were investigated by an atomic force microscope under physiological salt solution in natural environment. It was found that the structures of cells and fibers forming the cornea were observable on the ablated surface in the form of surface roughness. Scanning electron microscopic observations were also performed to compare the two surface investigation methods. It was found that this showed the same structures, but differently from the atomic force microscopic observation some distortions appeared produced by preparation processes of the samples, which were necessaries for the electron microscopic investigations.
{"title":"Surface roughness investigations of excimer-laser-ablated cornea","authors":"B. Hopp, A. Nógrádi, K. Revesz, Z. Bor, L. Kolozsvári","doi":"10.1117/12.316633","DOIUrl":"https://doi.org/10.1117/12.316633","url":null,"abstract":"The earlier investigations showed that the corneal haze can be due to the scattering effect of the excimer laser induced surface structure. In this paper a comparative study is presented regarding the development of these. Several human corneas were irradiated by an ArF excimer laser. The applied fluence was 193 mJ/cm2. The developed surface structures after each excimer pulse were investigated by an atomic force microscope under physiological salt solution in natural environment. It was found that the structures of cells and fibers forming the cornea were observable on the ablated surface in the form of surface roughness. Scanning electron microscopic observations were also performed to compare the two surface investigation methods. It was found that this showed the same structures, but differently from the atomic force microscopic observation some distortions appeared produced by preparation processes of the samples, which were necessaries for the electron microscopic investigations.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"216 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134118330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Balestrino, S. Martellucci, P. Medaglia, A. Paoletti, G. Petrocelli, M. Tonti
Pulsed laser deposition technique (PLD) has been successfully used to grow artificially layered films of the CuBa2(Ca1-xSrx)n-1 CunOy compound using only two targets having nominal composition BaCuOy and (Ca1-xSrx)CuOy respectively. n was varied between 2 and 5. The kinematic analysis of the x-ray diffraction spectra reveals that the average random discrete thickness fluctuations which affects both the BaCuOy and (Ca1-xSrx)CuOy layers are much smaller than one atomic layer. Such features are confirmed by the appearance of sharp peaks even for the nequals2 artificially layered structure where only one (Ca1-xSrx)CuOy cell is deposited in the stacking sequence. A major difference is found in the behavior of resistivity between films containing Sr and Ca respectively. Namely (BaCuO2)2/[(Ca1-xSrx)CuOy]n films never show any trace of superconductivity, while [BaCuO2]n/[CaCuO2]n films result to have, for growth oxygen pressures P > 0.2 mbar a full transition by laser deposition technique with a low interfacial disorder and give strong support to the idea of synthesizing new artificial high Tc structures by the PLD technique.
{"title":"Pulsed laser deposition of oxide cuprate superlattices","authors":"G. Balestrino, S. Martellucci, P. Medaglia, A. Paoletti, G. Petrocelli, M. Tonti","doi":"10.1117/12.316607","DOIUrl":"https://doi.org/10.1117/12.316607","url":null,"abstract":"Pulsed laser deposition technique (PLD) has been successfully used to grow artificially layered films of the CuBa2(Ca1-xSrx)n-1 CunOy compound using only two targets having nominal composition BaCuOy and (Ca1-xSrx)CuOy respectively. n was varied between 2 and 5. The kinematic analysis of the x-ray diffraction spectra reveals that the average random discrete thickness fluctuations which affects both the BaCuOy and (Ca1-xSrx)CuOy layers are much smaller than one atomic layer. Such features are confirmed by the appearance of sharp peaks even for the nequals2 artificially layered structure where only one (Ca1-xSrx)CuOy cell is deposited in the stacking sequence. A major difference is found in the behavior of resistivity between films containing Sr and Ca respectively. Namely (BaCuO2)2/[(Ca1-xSrx)CuOy]n films never show any trace of superconductivity, while [BaCuO2]n/[CaCuO2]n films result to have, for growth oxygen pressures P > 0.2 mbar a full transition by laser deposition technique with a low interfacial disorder and give strong support to the idea of synthesizing new artificial high Tc structures by the PLD technique.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123085227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We discuss the ability and effectiveness of electronic spectroscopy to reveal rotational isomerism by presenting some examples of the S1 implied by S0 electronic spectra of non-rigid molecules. One or two photon electronic spectra have multiple features when the molecule has more than one conformational preference. Torsional bands showing up in the spectrum complicate the assignment of conformers. Hole burning experiments give definite conclusions on the existence of rotational isomerism and an example from the literature is given.
{"title":"Observation of conformers with laser electronic spectroscopy in supersonic molecular beams","authors":"J. Philis, C. Kosmidis, P. Tsekeris","doi":"10.1117/12.316584","DOIUrl":"https://doi.org/10.1117/12.316584","url":null,"abstract":"We discuss the ability and effectiveness of electronic spectroscopy to reveal rotational isomerism by presenting some examples of the S1 implied by S0 electronic spectra of non-rigid molecules. One or two photon electronic spectra have multiple features when the molecule has more than one conformational preference. Torsional bands showing up in the spectrum complicate the assignment of conformers. Hole burning experiments give definite conclusions on the existence of rotational isomerism and an example from the literature is given.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132016136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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