Pub Date : 2002-01-01DOI: 10.1080/08981500290022789
J. Grum, D. Zuljan
Efficient control of laser cutting processes is closely related to knowledge of heat effects in the cutting front and its surroundings. Similar to other machining processes using high power densities, in laser cutting processes it is very important to monitor the heating phenomena in the specimen material due to heat input. The processes in the laser cutting front were monitored in three ways, i.e., by a voltage signal of infrared (IR) radiation from the cutting front by measuring surface profiles of laser cuts, and by macrographs of laser cut surfaces. In the paper it is shown that an analysis of macrographs showing surface-profile corrugation of the laser cut at austenitic stainless steel as well as at low-carbon steel can be used to confirm and analyse thermal phenomena in the cutting front. A comparison is given between the power spectra of the voltage signal of the IR radiation and those of the surface-corrugation profile for different steel grades, different specimen thicknesses, and various input e...
{"title":"Frequency analyses of a signal of IR radiation from the cutting front and surface profile height in laser cutting of austenitic stainless steel","authors":"J. Grum, D. Zuljan","doi":"10.1080/08981500290022789","DOIUrl":"https://doi.org/10.1080/08981500290022789","url":null,"abstract":"Efficient control of laser cutting processes is closely related to knowledge of heat effects in the cutting front and its surroundings. Similar to other machining processes using high power densities, in laser cutting processes it is very important to monitor the heating phenomena in the specimen material due to heat input. The processes in the laser cutting front were monitored in three ways, i.e., by a voltage signal of infrared (IR) radiation from the cutting front by measuring surface profiles of laser cuts, and by macrographs of laser cut surfaces. In the paper it is shown that an analysis of macrographs showing surface-profile corrugation of the laser cut at austenitic stainless steel as well as at low-carbon steel can be used to confirm and analyse thermal phenomena in the cutting front. A comparison is given between the power spectra of the voltage signal of the IR radiation and those of the surface-corrugation profile for different steel grades, different specimen thicknesses, and various input e...","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":"18 1","pages":"59-80"},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80143992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/08981500290022734
J. Marciak-kozlowska, M. Kozłowski
In this paper the interaction of attosecond laser pulses with matter is investigated. The scattering and motion of heat carriers as well as the external force are considered. The heat transport is described by the thermally forced Klein-Gordon or thermal modified telegraph equation depending on the ratio of the scattering and potential motion. In the case of the thermal Heisenberg type relation V ∽ E ( is the relaxation time and V is the potential) the heat transport is described by the thermal distortionless damped wave equation. In this paper the Klein-Gordon, modified telegraph 1 equation and wave equation are solved.
{"title":"Attophysics and technology with ultra short laser pulses","authors":"J. Marciak-kozlowska, M. Kozłowski","doi":"10.1080/08981500290022734","DOIUrl":"https://doi.org/10.1080/08981500290022734","url":null,"abstract":"In this paper the interaction of attosecond laser pulses with matter is investigated. The scattering and motion of heat carriers as well as the external force are considered. The heat transport is described by the thermally forced Klein-Gordon or thermal modified telegraph equation depending on the ratio of the scattering and potential motion. In the case of the thermal Heisenberg type relation V ∽ E ( is the relaxation time and V is the potential) the heat transport is described by the thermal distortionless damped wave equation. In this paper the Klein-Gordon, modified telegraph 1 equation and wave equation are solved.","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":"53 1","pages":"17-25"},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78565769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/08981500290022743
B. Yilbas
In order to improve the practical laser hole drilling application, the assessment of the end product quality is essential. One of the methods of assessing the hole quality is to analyze the features of hole geometric sections by statistical methods. In the present study, laser hole drilling in Inconel 617 alloy is considered and the factorial analysis based on the statistical technique is introduced when identifying the significance levels of the operational parameters. The parameters selected are drilling ambient pressure, laser output energy, focus settings of focusing lens, and workpiece thickness. In order to complete the factorial analysis, four levels of each parameter are taken into account. The laser drilled holes were cross-sectioned and examined under the microscope. A marking scheme is introduced to evaluate the geometric features of the hole cross-section. It is found that the workpiece thickness and focus setting are the most significant parameters for the formation of hole cross-section. The...
{"title":"Parametric study for laser hole drilling of Inconel 617 alloy","authors":"B. Yilbas","doi":"10.1080/08981500290022743","DOIUrl":"https://doi.org/10.1080/08981500290022743","url":null,"abstract":"In order to improve the practical laser hole drilling application, the assessment of the end product quality is essential. One of the methods of assessing the hole quality is to analyze the features of hole geometric sections by statistical methods. In the present study, laser hole drilling in Inconel 617 alloy is considered and the factorial analysis based on the statistical technique is introduced when identifying the significance levels of the operational parameters. The parameters selected are drilling ambient pressure, laser output energy, focus settings of focusing lens, and workpiece thickness. In order to complete the factorial analysis, four levels of each parameter are taken into account. The laser drilled holes were cross-sectioned and examined under the microscope. A marking scheme is introduced to evaluate the geometric features of the hole cross-section. It is found that the workpiece thickness and focus setting are the most significant parameters for the formation of hole cross-section. The...","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":"17 1","pages":"1-16"},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78866180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000054520
J. D. Hu, S. Tosto, Z. Guo, C. S. Wang
This article concerns functionally gradient materials (FGM) realized by laser sintering. Layers of Fe rich and Cu rich powders were compacted first and then laser sintered to obtain multilayer samples with smooth composition gradients. Microanalysis profiles on the cross sections of sintered samples show gradual increasing of Cu content and decreasing of Fe content. The laser sintered FGM contain several phases such as free graphite, ferrite, pearlite, Cu-Ni solid solutions, austenite, f -Cu phase, i -phase (Cu 31 Sn 8 ), k -phase (Cu 3 Sn) as well as m -phase (Cu 6 Sn 5 ). The experimental results show good wear resistance and toughness properties of the laser sintered FGMs.
研究了用激光烧结技术制备功能梯度材料。首先对富铁和富铜粉末进行压实，然后进行激光烧结，得到具有光滑成分梯度的多层样品。烧结试样截面上的微量分析曲线显示Cu含量逐渐增加，Fe含量逐渐减少。激光烧结FGM含有游离石墨、铁素体、珠光体、Cu- ni固溶体、奥氏体、f -Cu相、i相(Cu 31 Sn 8)、k相(Cu 3 Sn)和m相(Cu 6 Sn 5)等多种相。实验结果表明，激光烧结fgm具有良好的耐磨性和韧性。
{"title":"FUNCTIONALLY GRADED MATERIALS BY LASER SINTERING","authors":"J. D. Hu, S. Tosto, Z. Guo, C. S. Wang","doi":"10.1080/0898150021000054520","DOIUrl":"https://doi.org/10.1080/0898150021000054520","url":null,"abstract":"This article concerns functionally gradient materials (FGM) realized by laser sintering. Layers of Fe rich and Cu rich powders were compacted first and then laser sintered to obtain multilayer samples with smooth composition gradients. Microanalysis profiles on the cross sections of sintered samples show gradual increasing of Cu content and decreasing of Fe content. The laser sintered FGM contain several phases such as free graphite, ferrite, pearlite, Cu-Ni solid solutions, austenite, f -Cu phase, i -phase (Cu 31 Sn 8 ), k -phase (Cu 3 Sn) as well as m -phase (Cu 6 Sn 5 ). The experimental results show good wear resistance and toughness properties of the laser sintered FGMs.","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":"341 1","pages":"239-245"},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77777935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000014074
M. Kozłowski, J. Marciak-kozlowska
In this paper the TESLA, free-electron laser (FEL) pulse interaction with matter is investigated. The hyperbolic heat transport equation and its solution are discussed. It is shown that as the result of the interaction, damped thermal waves of both types: undistorted and dispersed can be emitted.
{"title":"Possible thermal waves generation by Femtosecond TESLA Free Electron Laser (FEL)","authors":"M. Kozłowski, J. Marciak-kozlowska","doi":"10.1080/0898150021000014074","DOIUrl":"https://doi.org/10.1080/0898150021000014074","url":null,"abstract":"In this paper the TESLA, free-electron laser (FEL) pulse interaction with matter is investigated. The hyperbolic heat transport equation and its solution are discussed. It is shown that as the result of the interaction, damped thermal waves of both types: undistorted and dispersed can be emitted.","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":"65 1","pages":"95-101"},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76993332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000039310
J. Marciak-kozlowska, M. Kozłowski
The thermal phenomena induced by zeptosecond (10 m 21 s) laser pulses are discussed in this article. Considering the theoretical proposal of the lasetron , the Heaviside equation for heat transport on zeptosecond time scale is formulated. In the article, the modified Schrodinger equation (Janina Marciak-koz ^ owska and Miros ^ aw Koz ^ owski (2002). Lasers in Engineering , 12 , 53) for quantum phenomena on the zeptosecond time scale was also discussed.
讨论了zeptosecond (10 m 21 s)激光脉冲引起的热现象。考虑到激光加速器的理论建议，建立了热输运的齐秒时间尺度的Heaviside方程。在文章中，修正薛定谔方程(Janina Marciak-koz ^ owska和Miros ^ aw Koz ^ owski(2002)。激光工程，12,53)也讨论了在zepto秒时间尺度上的量子现象。
{"title":"Causal heat transport induced by zeptosecond laser pulses","authors":"J. Marciak-kozlowska, M. Kozłowski","doi":"10.1080/0898150021000039310","DOIUrl":"https://doi.org/10.1080/0898150021000039310","url":null,"abstract":"The thermal phenomena induced by zeptosecond (10 m 21 s) laser pulses are discussed in this article. Considering the theoretical proposal of the lasetron , the Heaviside equation for heat transport on zeptosecond time scale is formulated. In the article, the modified Schrodinger equation (Janina Marciak-koz ^ owska and Miros ^ aw Koz ^ owski (2002). Lasers in Engineering , 12 , 53) for quantum phenomena on the zeptosecond time scale was also discussed.","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":"28 1","pages":"201-206"},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82311178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000054548
Feng Sun, Wenfeng Yu, Zu-hai Cheng, Yaoning Zhang
A new kind of phase change material (PCM) cooled mirror for use in the resonator of high power lasers is proposed. The PCM cooled mirror can minimize the thermal deformation on the reflecting surface effectively. A test setup was designed and the laser-induced thermal deformation of honeycombed PCM cooled mirror was measured at real time. Compared with a solid silicon mirror, it was only 0.45 µm at the tenth second of laser irradiation after absorbing 140 W net heat. In addition, the influence of the method of support on the thermal deformation was studied by experiments and showed that a simple support is compatible with a PCM cooled mirror.
{"title":"Experimental study of thermal deformation of honeycombed PCM cooled mirror in resonator","authors":"Feng Sun, Wenfeng Yu, Zu-hai Cheng, Yaoning Zhang","doi":"10.1080/0898150021000054548","DOIUrl":"https://doi.org/10.1080/0898150021000054548","url":null,"abstract":"A new kind of phase change material (PCM) cooled mirror for use in the resonator of high power lasers is proposed. The PCM cooled mirror can minimize the thermal deformation on the reflecting surface effectively. A test setup was designed and the laser-induced thermal deformation of honeycombed PCM cooled mirror was measured at real time. Compared with a solid silicon mirror, it was only 0.45 µm at the tenth second of laser irradiation after absorbing 140 W net heat. In addition, the influence of the method of support on the thermal deformation was studied by experiments and showed that a simple support is compatible with a PCM cooled mirror.","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":"406 1","pages":"271-280"},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79947699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000039301
R. Kaul, P. Ganesh, M. Tiwari, A. Singh, P. Tripathi, Ajay Gupta, A. Nath
Hardfacing by Stellite is extensively employed in many engineering applications for enhancing high temperature wear, oxidation and corrosion resistance of austenitic stainless steel components. These overlaid components, because of large difference in thermo-physical and mechanical properties between clad and substrate, are largely prone to cracking. Cracking resistance of Stellite 6 clad austenitic stainless steel components can be greatly enhanced by providing smooth composition gradient across substrate-clad interface. This article presents development of graded overlay of Stellite 6 on AISI 304 stainless steel substrate using 2.5 kW continuous wave CO 2 laser and their comparison with directly Stellite 6 clad AISI 304 stainless steel specimens. Graded overlaying of Stellite 6 effected significant reduction in microhardness gradient across substrate-clad interface with respect to that of directly Stellite 6 clad specimens. Thermal cycling tests, performed on laser-cladded specimens, demonstrated superi...
{"title":"Laser assisted deposition of graded overlay of Stellite 6 on austenitic stainless steel","authors":"R. Kaul, P. Ganesh, M. Tiwari, A. Singh, P. Tripathi, Ajay Gupta, A. Nath","doi":"10.1080/0898150021000039301","DOIUrl":"https://doi.org/10.1080/0898150021000039301","url":null,"abstract":"Hardfacing by Stellite is extensively employed in many engineering applications for enhancing high temperature wear, oxidation and corrosion resistance of austenitic stainless steel components. These overlaid components, because of large difference in thermo-physical and mechanical properties between clad and substrate, are largely prone to cracking. Cracking resistance of Stellite 6 clad austenitic stainless steel components can be greatly enhanced by providing smooth composition gradient across substrate-clad interface. This article presents development of graded overlay of Stellite 6 on AISI 304 stainless steel substrate using 2.5 kW continuous wave CO 2 laser and their comparison with directly Stellite 6 clad AISI 304 stainless steel specimens. Graded overlaying of Stellite 6 effected significant reduction in microhardness gradient across substrate-clad interface with respect to that of directly Stellite 6 clad specimens. Thermal cycling tests, performed on laser-cladded specimens, demonstrated superi...","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":"23 1","pages":"207-225"},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74043023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000054511
T. Maiwald, R. Galun, B. Mordike, F. J. Feikus
The aim of this investigation was the production of wear and corrosion resistant coatings on magnesium base alloys. In particular it was proposed to generate by laser layers which operate as cylinder liners in a magnesium engine block thus replacing the currently used cast iron cylinder liners used in aluminium engines. These layers were produced using a 10 kW CO 2 laser and powder mixtures of aluminium + copper, aluminium + silicon and an alloyed aluminium-silicon powder in the single step process. The properties of these layers were characterised by metallographic investigations such as optical and scanning electron microscope and hardness measurements. The corrosion resistance has been determined using a modified immersion test in sulphuric acid with drying cycles in air. These conditions are comparable to the conditions found in combustion engines where the layers are to be used. Positive results were obtained with respect to the microstructure formation. Intermetallic phases can ensure a good wear re...
{"title":"Microstructure and corrosion properties of laser clads of magnesium base alloys for laser generated cylinder liners","authors":"T. Maiwald, R. Galun, B. Mordike, F. J. Feikus","doi":"10.1080/0898150021000054511","DOIUrl":"https://doi.org/10.1080/0898150021000054511","url":null,"abstract":"The aim of this investigation was the production of wear and corrosion resistant coatings on magnesium base alloys. In particular it was proposed to generate by laser layers which operate as cylinder liners in a magnesium engine block thus replacing the currently used cast iron cylinder liners used in aluminium engines. These layers were produced using a 10 kW CO 2 laser and powder mixtures of aluminium + copper, aluminium + silicon and an alloyed aluminium-silicon powder in the single step process. The properties of these layers were characterised by metallographic investigations such as optical and scanning electron microscope and hardness measurements. The corrosion resistance has been determined using a modified immersion test in sulphuric acid with drying cycles in air. These conditions are comparable to the conditions found in combustion engines where the layers are to be used. Positive results were obtained with respect to the microstructure formation. Intermetallic phases can ensure a good wear re...","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":"73 1","pages":"227-238"},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75126445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000030111
K. Kobylańska-Szkaradek
This work describes the influence of laser treatment on the structure and some properties of Al 2 O 3 , Al 2 O 3 + 5%Ni, Al 2 O 3 (95%Ni + 5%Al), Al 2 O 3 + 5%Ni - (95%Ni + 5%Al) and Al 2 O 3 + 5%Ni + CrAl layer oxide ceramic coatings of about 100 m thickness deposited by air plasma spraying on a heat-resistant alloy with a nickel matrix. It has been stated that laser remelting of power density 0.01-0.2 10 9 W m 2 and scanning rate within 5-7 m min 1 ensures good quality of ceramic coatings in comparison with not-remelted coatings. Laser treated ceramic coatings have a better thermal conductivity than as deposited layers. As shown by model calculations, after laser treatment, they show a smaller temperature drop over a given thickness. The erosion resistance of the coatings, however, is greater after laser treatment.
{"title":"Laser-beam modification of oxide thermal barrier coatings deposited by plasma spraying in air","authors":"K. Kobylańska-Szkaradek","doi":"10.1080/0898150021000030111","DOIUrl":"https://doi.org/10.1080/0898150021000030111","url":null,"abstract":"This work describes the influence of laser treatment on the structure and some properties of Al 2 O 3 , Al 2 O 3 + 5%Ni, Al 2 O 3 (95%Ni + 5%Al), Al 2 O 3 + 5%Ni - (95%Ni + 5%Al) and Al 2 O 3 + 5%Ni + CrAl layer oxide ceramic coatings of about 100 m thickness deposited by air plasma spraying on a heat-resistant alloy with a nickel matrix. It has been stated that laser remelting of power density 0.01-0.2 10 9 W m 2 and scanning rate within 5-7 m min 1 ensures good quality of ceramic coatings in comparison with not-remelted coatings. Laser treated ceramic coatings have a better thermal conductivity than as deposited layers. As shown by model calculations, after laser treatment, they show a smaller temperature drop over a given thickness. The erosion resistance of the coatings, however, is greater after laser treatment.","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":"5 1","pages":"311-327"},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88272863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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