Pub Date : 2003-09-01DOI: 10.1142/S1465876303001605
A. Randles, B. Pokines, Shuji Tanaka, M. Esashi
The present work is an investigation and characterization of a new technique for etching and masking lithium niobate (LiNbO3) to realize high aspect ratio structures. LiNbO3 is a single crystal, optically clear (from 350 nanometer to 5 micrometer wavelength) piezoelectric and electro-optical material. It is inert to most reactants and has a high Curie temperature. These properties allow LiNbO3 to be used as a sensor or actuator in harsh environments or as an optical modulator. Multi-level lithium niobate deep etching techniques are currently unavailable or limited. The present work uses a chrome gold mask with a solution of hydrofluoric acid and nitric acid at 80 °C to etch the LiNbO3. The novel wet etch method developed yields an etch rate of 30 micrometer per hour on the -z face and less than 250 nm per hour on the +z face. In the experimentation done with this research trenches 80 micrometers deep were fabricated. Experimental etch and results are detailed.
{"title":"Deep Structures Wet Etched Into Lithium Niobate Using A Physical Mask","authors":"A. Randles, B. Pokines, Shuji Tanaka, M. Esashi","doi":"10.1142/S1465876303001605","DOIUrl":"https://doi.org/10.1142/S1465876303001605","url":null,"abstract":"The present work is an investigation and characterization of a new technique for etching and masking lithium niobate (LiNbO3) to realize high aspect ratio structures. LiNbO3 is a single crystal, optically clear (from 350 nanometer to 5 micrometer wavelength) piezoelectric and electro-optical material. It is inert to most reactants and has a high Curie temperature. These properties allow LiNbO3 to be used as a sensor or actuator in harsh environments or as an optical modulator. Multi-level lithium niobate deep etching techniques are currently unavailable or limited. The present work uses a chrome gold mask with a solution of hydrofluoric acid and nitric acid at 80 °C to etch the LiNbO3. The novel wet etch method developed yields an etch rate of 30 micrometer per hour on the -z face and less than 250 nm per hour on the +z face. In the experimentation done with this research trenches 80 micrometers deep were fabricated. Experimental etch and results are detailed.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114708228","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}
Pub Date : 2003-09-01DOI: 10.1142/S1465876303001976
S. Deng, Jun Wei, C. Tan, M. L. Nai, W. B. Yu, H. Xie
Low temperature bonding of two silicon wafers with significant high bond strength has been prepared successfully using sol-gel coating as intermediate layer. The effects of bonding temperature, solution aging time and spin speed on bonding quality have been investigated by a full 23 factorial design. Under the 75% confidence level, the statistic result shows that only the interaction effect between bonding temperature and spin speed is significant. Design of experiments (DoE) is used to study the effects of key parameters on bond strength, and bonding mechanism are discussed. The possible reason for the observed high bond strength is the absence of absorbed water on the smooth coating surface, which results in the direct condensation reactions between OH groups to form strong Si-O-Si bonds even at low temperatures.
{"title":"Low Temperature Silicon Wafer Bonding By Sol-Gel Processing","authors":"S. Deng, Jun Wei, C. Tan, M. L. Nai, W. B. Yu, H. Xie","doi":"10.1142/S1465876303001976","DOIUrl":"https://doi.org/10.1142/S1465876303001976","url":null,"abstract":"Low temperature bonding of two silicon wafers with significant high bond strength has been prepared successfully using sol-gel coating as intermediate layer. The effects of bonding temperature, solution aging time and spin speed on bonding quality have been investigated by a full 23 factorial design. Under the 75% confidence level, the statistic result shows that only the interaction effect between bonding temperature and spin speed is significant. Design of experiments (DoE) is used to study the effects of key parameters on bond strength, and bonding mechanism are discussed. The possible reason for the observed high bond strength is the absence of absorbed water on the smooth coating surface, which results in the direct condensation reactions between OH groups to form strong Si-O-Si bonds even at low temperatures.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129989520","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}
Pub Date : 2003-09-01DOI: 10.1142/S1465876303001903
H. Liu, S. Wan, G. Lim, A. Tay
This paper presents the design, realization and simulation of a novel polymer based check-valve micropump actuated by piezoelectric disc. Comparing with silicon substrate, polymer materials have such advantages as flexibility, chemical and biological compatibility, 3D fabrication possibility and low cost in material and mass production. Laser micromachining technology and precision engineering techniques were used to fabricate the prototype with the dimension of Φ20mm×5.2mm. Result of preliminary experiments on fusion bonding between polyimide and polycarbonate are also presented. Due to the small difference between their glass transition temperatures (Tg) the polyimide and polycarbonate could be bonded together relatively easily. A special fixture for the bonding process has been designed and made to control the lateral and vertical expansion less than 1.5%. Using DI water as the pumping medium, the presented micropump is expected to achieve self-priming, bubble tolerance and low power consumption and a flow rate of 30μl/min at the resonance frequency of 300Hz. A planar format micropump will be delivered based on this presented successful design for mass fabrication.
{"title":"The Development Of A Polymer Based Piezo-Actuated Micropump","authors":"H. Liu, S. Wan, G. Lim, A. Tay","doi":"10.1142/S1465876303001903","DOIUrl":"https://doi.org/10.1142/S1465876303001903","url":null,"abstract":"This paper presents the design, realization and simulation of a novel polymer based check-valve micropump actuated by piezoelectric disc. Comparing with silicon substrate, polymer materials have such advantages as flexibility, chemical and biological compatibility, 3D fabrication possibility and low cost in material and mass production. Laser micromachining technology and precision engineering techniques were used to fabricate the prototype with the dimension of Φ20mm×5.2mm. Result of preliminary experiments on fusion bonding between polyimide and polycarbonate are also presented. Due to the small difference between their glass transition temperatures (Tg) the polyimide and polycarbonate could be bonded together relatively easily. A special fixture for the bonding process has been designed and made to control the lateral and vertical expansion less than 1.5%. Using DI water as the pumping medium, the presented micropump is expected to achieve self-priming, bubble tolerance and low power consumption and a flow rate of 30μl/min at the resonance frequency of 300Hz. A planar format micropump will be delivered based on this presented successful design for mass fabrication.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129751632","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}
Pub Date : 2003-09-01DOI: 10.1142/S1465876303001587
P. Pal, S. Tuli, S. Chandra
In the present work, we report a novel process for fabricating suspended silicon dioxide micro-structures inside the anisotropically etched cavity formed in (100) silicon wafers. Using this new process, the moving parts are "recessed" in the substrate which can be packaged and handled easily compared to non-recessed structures. In the fabrication process, spin coated liquid photoresist is used. There is a common problem of thinning of photoresist on convex edges of the cavity during photolithography steps. As a result, silicon dioxide is etched away from these edges. During subsequent anisotropic etching of silicon to release the microstructures, the unprotected convex edges are also etched resulting in failure of the process. To overcome this problem, two different methods are used. In the first method, high viscosity positive photoresist (Shipley STR-1045) is used and the multiple coatings are carried out to cover the convex edges adequately. This protects the oxide on convex edges in buffered hydrofluo...
{"title":"Design And Fabrication Of SIO2 Micromechanical Structures Inside Anisotropically Etched Cavity","authors":"P. Pal, S. Tuli, S. Chandra","doi":"10.1142/S1465876303001587","DOIUrl":"https://doi.org/10.1142/S1465876303001587","url":null,"abstract":"In the present work, we report a novel process for fabricating suspended silicon dioxide micro-structures inside the anisotropically etched cavity formed in (100) silicon wafers. Using this new process, the moving parts are \"recessed\" in the substrate which can be packaged and handled easily compared to non-recessed structures. In the fabrication process, spin coated liquid photoresist is used. There is a common problem of thinning of photoresist on convex edges of the cavity during photolithography steps. As a result, silicon dioxide is etched away from these edges. During subsequent anisotropic etching of silicon to release the microstructures, the unprotected convex edges are also etched resulting in failure of the process. To overcome this problem, two different methods are used. In the first method, high viscosity positive photoresist (Shipley STR-1045) is used and the multiple coatings are carried out to cover the convex edges adequately. This protects the oxide on convex edges in buffered hydrofluo...","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130049259","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}
Pub Date : 2003-09-01DOI: 10.1142/S1465876303002155
Z. Zhong, K. Goh
By extending the bonding-tool life, the saving can be quite substantial. This paper demonstrates how the integration of new technological development in ceramic bonding tools to the base ceramic material with new treatment processes, extends the tool life by at least 2 times its current limit. No change in the dimensions, surface finish or appearance of the bonding tool as seen after it was processed, resulting in a more portable and repeatable process. Experimental results confirmed the potential capability of the treated capillary to go beyond the process capability presently in existence.
{"title":"New Development To Extend The Tool Life Of Ceramic Bonding Tools","authors":"Z. Zhong, K. Goh","doi":"10.1142/S1465876303002155","DOIUrl":"https://doi.org/10.1142/S1465876303002155","url":null,"abstract":"By extending the bonding-tool life, the saving can be quite substantial. This paper demonstrates how the integration of new technological development in ceramic bonding tools to the base ceramic material with new treatment processes, extends the tool life by at least 2 times its current limit. No change in the dimensions, surface finish or appearance of the bonding tool as seen after it was processed, resulting in a more portable and repeatable process. Experimental results confirmed the potential capability of the treated capillary to go beyond the process capability presently in existence.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114076002","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}
Pub Date : 2003-09-01DOI: 10.1142/S1465876303001939
Wei Zhang, X. Yao, Xiaoqing Wu
Two-dimensional thermal analysis of multi-layer thin film pyroelectric infrared detectors is performed according to the structure and test conditions of detectors and the temperature distribution of detectors is obtained. Result shows that the insulation layer of multi-layer film pyroelectric infrared detector can effectively reduce thermal flow from pyroelectric layer substrate and the response of detector increases with the increasing of insulation layer thickness; when the thermal conductivity of insulation layer is lower than of air, its performance is better than micro-bridge structure.
{"title":"Two-Dimensional Thermal Analysis Of Multi-Layer Thin Film Pyroelectric Infrared Detectors","authors":"Wei Zhang, X. Yao, Xiaoqing Wu","doi":"10.1142/S1465876303001939","DOIUrl":"https://doi.org/10.1142/S1465876303001939","url":null,"abstract":"Two-dimensional thermal analysis of multi-layer thin film pyroelectric infrared detectors is performed according to the structure and test conditions of detectors and the temperature distribution of detectors is obtained. Result shows that the insulation layer of multi-layer film pyroelectric infrared detector can effectively reduce thermal flow from pyroelectric layer substrate and the response of detector increases with the increasing of insulation layer thickness; when the thermal conductivity of insulation layer is lower than of air, its performance is better than micro-bridge structure.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122961848","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}
Pub Date : 2003-09-01DOI: 10.1142/S1465876303001575
K. Bhat, B. Reddy, V. V. Kumar, K. Kumar, Y. Sushma, N. Babu, K. Natarajan
In this paper the design, fabrication and testing of the capacitive micro accelerometer with Silicon On Insulator (SOI) approach is presented. The beam location with respect to a rectangular mass is optimized, using finite element analysis (FEM) to minimize cross axis sensitivity. It is demonstrated that a simple KOH etching with the addition of the tert-butanol can be easily adopted to fabricate the accelerometer structure without any convex undercutting effects. The devices are tested by electrostatic actuation.
{"title":"Design Optimization, Fabrication And Testing Of A Capacitive Silicon Accelerometer Using An Soi Approach","authors":"K. Bhat, B. Reddy, V. V. Kumar, K. Kumar, Y. Sushma, N. Babu, K. Natarajan","doi":"10.1142/S1465876303001575","DOIUrl":"https://doi.org/10.1142/S1465876303001575","url":null,"abstract":"In this paper the design, fabrication and testing of the capacitive micro accelerometer with Silicon On Insulator (SOI) approach is presented. The beam location with respect to a rectangular mass is optimized, using finite element analysis (FEM) to minimize cross axis sensitivity. It is demonstrated that a simple KOH etching with the addition of the tert-butanol can be easily adopted to fabricate the accelerometer structure without any convex undercutting effects. The devices are tested by electrostatic actuation.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130413238","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}
Pub Date : 2003-09-01DOI: 10.1142/S1465876303002064
M. Hu, H. Du, S. Ling, Bo Liu
This paper presents a bulk micromachined check valve with very high frequency and extremely low leak rates. The valve is designed to have a hexagonal orifice, a hexagonal membrane flap and three flexible tethers. The three elbow-shaped flexible tethers are used both to secure the membrane flap to the valve seat and to abtain a large flap displacement in the forward flow direction. SOI wafer and DRIE technology are used to implement this micro valve. A very simple farbication process has been developed, and only two photolithographic masks are employed. Preliminary testing on a 1.5 milimeters size check valve shows that a maximum flow rate (DI water) of 35.6ml/min was obtained at pressure drop of 65.5kPa and negligible leakage rate in the reverse flow direction observed at pressure up to 600kPa.
{"title":"Development Of An Soi-Based Micro Check Valve","authors":"M. Hu, H. Du, S. Ling, Bo Liu","doi":"10.1142/S1465876303002064","DOIUrl":"https://doi.org/10.1142/S1465876303002064","url":null,"abstract":"This paper presents a bulk micromachined check valve with very high frequency and extremely low leak rates. The valve is designed to have a hexagonal orifice, a hexagonal membrane flap and three flexible tethers. The three elbow-shaped flexible tethers are used both to secure the membrane flap to the valve seat and to abtain a large flap displacement in the forward flow direction. SOI wafer and DRIE technology are used to implement this micro valve. A very simple farbication process has been developed, and only two photolithographic masks are employed. Preliminary testing on a 1.5 milimeters size check valve shows that a maximum flow rate (DI water) of 35.6ml/min was obtained at pressure drop of 65.5kPa and negligible leakage rate in the reverse flow direction observed at pressure up to 600kPa.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124714787","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}
Pub Date : 2003-09-01DOI: 10.1142/S1465876303001460
Y. C. Lin, J. Chiou, C. L. Chen
A digital/analog electrostatic actuating mechanism that can be applied for optical applications is presented. The mechanism is composed of electrostatic actuators with nails and clamped torsion beams. Based on the pull-in phenomena of electrostatics and the morph-shape bending of the actuators, the mechanism can be used to achieve digital/analog motions depending upon the applied voltage-range. Finite element model of the electrostatic actuator had been simulated to demonstrate the concept of actuation principle when the applied voltage is increased. Two functional micromirror devices were developed using Poly-MUMPs process to demonstrate the actuating abilities and its corresponding performances. Simulations and experimental results indicated that developed tilting micromirror could reach 2.5 ~ 4.2-degree digital tilting angle with 1-degree analog fine-tuning range. With fine-tuning function, the micromirror device is adaptive to the environmental drifts that could be applied for precise positioning in optical switching applications. The linear analog-tuning characteristic provides a solution for optical scanning applications. For the case of micromirror device that could achieve piston/rotation motions, the digital/analog mechanism is applied to realize optical phase/amplitude modulations. Experiments indicated that the micromirror could achieve 0.3 μm-displacement in piston and 0.8-degree angle in rotation.
{"title":"A Digital/Analog Electrostatic Actuating Mechanism For Optical Applications","authors":"Y. C. Lin, J. Chiou, C. L. Chen","doi":"10.1142/S1465876303001460","DOIUrl":"https://doi.org/10.1142/S1465876303001460","url":null,"abstract":"A digital/analog electrostatic actuating mechanism that can be applied for optical applications is presented. The mechanism is composed of electrostatic actuators with nails and clamped torsion beams. Based on the pull-in phenomena of electrostatics and the morph-shape bending of the actuators, the mechanism can be used to achieve digital/analog motions depending upon the applied voltage-range. Finite element model of the electrostatic actuator had been simulated to demonstrate the concept of actuation principle when the applied voltage is increased. Two functional micromirror devices were developed using Poly-MUMPs process to demonstrate the actuating abilities and its corresponding performances. Simulations and experimental results indicated that developed tilting micromirror could reach 2.5 ~ 4.2-degree digital tilting angle with 1-degree analog fine-tuning range. With fine-tuning function, the micromirror device is adaptive to the environmental drifts that could be applied for precise positioning in optical switching applications. The linear analog-tuning characteristic provides a solution for optical scanning applications. For the case of micromirror device that could achieve piston/rotation motions, the digital/analog mechanism is applied to realize optical phase/amplitude modulations. Experiments indicated that the micromirror could achieve 0.3 μm-displacement in piston and 0.8-degree angle in rotation.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132066001","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}
Pub Date : 2003-09-01DOI: 10.1142/S1465876303001642
X. Zeng, J. Li, X. Sun, G. Qi, X. Zeng
This study is on a new approach for fabrication of poly-Si thin films. Aluminum-induced crystallization of a-Si film has been achieved by thermal annealing only at around 400 °C. The Experimental results reveal that the Al on top of a-Si arrangement has more evident effect in crystallization enhancement than that with Al under a-Si, and the resultant poly-Si films show preferred (400) crystal orientation. It is verified that aluminum can cause lateral crystallization of a-Si film. No preferred orientation was noticed from lateral crystallization samples.
{"title":"Polycrystalline Silicon Thin Film Obtained By Aluminum Induced Crystallization","authors":"X. Zeng, J. Li, X. Sun, G. Qi, X. Zeng","doi":"10.1142/S1465876303001642","DOIUrl":"https://doi.org/10.1142/S1465876303001642","url":null,"abstract":"This study is on a new approach for fabrication of poly-Si thin films. Aluminum-induced crystallization of a-Si film has been achieved by thermal annealing only at around 400 °C. The Experimental results reveal that the Al on top of a-Si arrangement has more evident effect in crystallization enhancement than that with Al under a-Si, and the resultant poly-Si films show preferred (400) crystal orientation. It is verified that aluminum can cause lateral crystallization of a-Si film. No preferred orientation was noticed from lateral crystallization samples.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133398345","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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