Pub Date : 2018-08-30DOI: 10.24423/ENGTRANS.860.20180830
Shan-ming Luo, Longxing Liao, Jingyu Mo
End milling method is applied to machining of cycloidal gears to improve the cutting quality and efficiency. The influence of milling parameters on the surface roughness is investigated based upon orthogonal tests with the four factors and four levels, as well as analysis of range and variance. A model to predict the surface roughness is built up on basis of the probability statistics and multivariate nonlinear regression analysis. Significance tests are conducted on the prediction model, and the interactive effect of these parameters on the surface roughness is figured out so as to propose optimization schemes. The results show that the shaft inclination angle has the biggest impact on the surface roughness, followed by the feed per tooth, the radial feed and the spindle speed. The prediction model of surface roughness is proved to have high prediction accuracy. This study aims to provide references for the improvement of machining quality of cycloidal gears and optimization of milling parameters.
{"title":"Prediction of Surface Roughness of End Milling for Cycloidal Gears Based on Orthogonal Tests","authors":"Shan-ming Luo, Longxing Liao, Jingyu Mo","doi":"10.24423/ENGTRANS.860.20180830","DOIUrl":"https://doi.org/10.24423/ENGTRANS.860.20180830","url":null,"abstract":"End milling method is applied to machining of cycloidal gears to improve the cutting quality and efficiency. The influence of milling parameters on the surface roughness is investigated based upon orthogonal tests with the four factors and four levels, as well as analysis of range and variance. A model to predict the surface roughness is built up on basis of the probability statistics and multivariate nonlinear regression analysis. Significance tests are conducted on the prediction model, and the interactive effect of these parameters on the surface roughness is figured out so as to propose optimization schemes. The results show that the shaft inclination angle has the biggest impact on the surface roughness, followed by the feed per tooth, the radial feed and the spindle speed. The prediction model of surface roughness is proved to have high prediction accuracy. This study aims to provide references for the improvement of machining quality of cycloidal gears and optimization of milling parameters.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44789334","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 : 2018-08-27DOI: 10.24423/ENGTRANS.401.20180928
R. Chand, G. C. Rana, D. Puigjaner
The purpose of this paper is to study the thermal instability analysis of an elastico-viscous nanofluid layer heated from below. The Rivlin-Ericksen type fluid model is used to describe the rheological behavior of an elastico-viscous nanofluid. The linear stability criterion for the onset of both stationary and oscillatory convection is derived by applying the normal model analysis method. The presence of nanoparticles enhances the thermal conductivity of the fluid, and the model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The effect of the physical parameters of the system, namely the concentration Rayleigh number, Prandtl number, capacity ratio, Lewis number, and kinematic visco-elasticity coefficient, on the stability of the system is numerically investigated. In addition, sufficient conditions for the non-existence of oscillatory convection are reported.
{"title":"Thermal Instability Analysis of an Elastico-Viscous Nanofluid Layer","authors":"R. Chand, G. C. Rana, D. Puigjaner","doi":"10.24423/ENGTRANS.401.20180928","DOIUrl":"https://doi.org/10.24423/ENGTRANS.401.20180928","url":null,"abstract":"The purpose of this paper is to study the thermal instability analysis of an elastico-viscous nanofluid layer heated from below. The Rivlin-Ericksen type fluid model is used to describe the rheological behavior of an elastico-viscous nanofluid. The linear stability criterion for the onset of both stationary and oscillatory convection is derived by applying the normal model analysis method. The presence of nanoparticles enhances the thermal conductivity of the fluid, and the model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The effect of the physical parameters of the system, namely the concentration Rayleigh number, Prandtl number, capacity ratio, Lewis number, and kinematic visco-elasticity coefficient, on the stability of the system is numerically investigated. In addition, sufficient conditions for the non-existence of oscillatory convection are reported.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41722833","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 : 2018-08-27DOI: 10.24423/ENGTRANS.903.20180928
Olga Kawa, Przemysław Litewka, R. Studziński
In this paper a numerical analysis of contact between three-dimensional elastic beams with deformations at the contact zone is carried out. The authors propose a new model of beam-to-beam contact which is the continuation of ideas presented in [6, 7, 10]. The results of beam-to-beam contact analysis are compared with the ones for full 3D problem solved in the abaqus/enviroment. The aim of the conducted numerical simulations was to select the most appropriate 3D model and to use it as a reference to verify the accuracy of the proposed beam-to-beam contact definition. The verifications were carried out for contact between beams with circular cross-sections. The obtained contact forces and the displacements of beams tips for different beams arrangements and boundary conditions showed a satisfactory correlation.
{"title":"Contact Between 3D Beams with Deformable Circular Cross-Sections – Numerical Verification","authors":"Olga Kawa, Przemysław Litewka, R. Studziński","doi":"10.24423/ENGTRANS.903.20180928","DOIUrl":"https://doi.org/10.24423/ENGTRANS.903.20180928","url":null,"abstract":"In this paper a numerical analysis of contact between three-dimensional elastic beams with deformations at the contact zone is carried out. The authors propose a new model of beam-to-beam contact which is the continuation of ideas presented in [6, 7, 10]. The results of beam-to-beam contact analysis are compared with the ones for full 3D problem solved in the abaqus/enviroment. The aim of the conducted numerical simulations was to select the most appropriate 3D model and to use it as a reference to verify the accuracy of the proposed beam-to-beam contact definition. The verifications were carried out for contact between beams with circular cross-sections. The obtained contact forces and the displacements of beams tips for different beams arrangements and boundary conditions showed a satisfactory correlation.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46850254","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 : 2018-08-27DOI: 10.24423/ENGTRANS.890.20180827
R. R. Reddy, Bala Anki Reddy Polu
This theoretical research work deals with the effect of aligned magnetic field flow and heat transfer of carbon nanotubes towards a nonlinear stretching sheet. In addition, we have considered two kinds of carbon nanotubes, namely SWCNTs and MWCNTs, used with water as the base fluid. The governing boundary layer flow equations narrating partial differential equations are transformed into a system of ordinary differential equations with the assistance of similarity transformation. Obtained coupled non-linear differential equations are solved by fourth-order Runge-Kutta (R-K) method along with shooting technique. A comparative study of the formerly published results and the present results for a special case shows that all these results are in an excellent agreement.
{"title":"Numerical Solution of MHD Casson Fluid Flow Due to a Moving Extensible Surface with Second-Order Velocity Slip and Carbon Nanotubes","authors":"R. R. Reddy, Bala Anki Reddy Polu","doi":"10.24423/ENGTRANS.890.20180827","DOIUrl":"https://doi.org/10.24423/ENGTRANS.890.20180827","url":null,"abstract":"This theoretical research work deals with the effect of aligned magnetic field flow and heat transfer of carbon nanotubes towards a nonlinear stretching sheet. In addition, we have considered two kinds of carbon nanotubes, namely SWCNTs and MWCNTs, used with water as the base fluid. The governing boundary layer flow equations narrating partial differential equations are transformed into a system of ordinary differential equations with the assistance of similarity transformation. Obtained coupled non-linear differential equations are solved by fourth-order Runge-Kutta (R-K) method along with shooting technique. A comparative study of the formerly published results and the present results for a special case shows that all these results are in an excellent agreement.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47674570","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 : 2018-08-09DOI: 10.24423/ENGTRANS.898.20180809
K. Magnucki, J. Lewiński
The paper is devoted to an analytical model of I-beam, with consideration of the shear effect. The model is based on the sandwich beam theory. The field displacements and strains are formulated with consideration of a nonlinear hypothesis of flat cross-section deformation of the beam. The governing differential equations for the I-beam are obtained based on the principle of stationary total potential energy. The shear effect of the beam is illustrated for the threepoint bending case. The analytical solution is compared to FEM numerical calculation. The results of the analysis are presented in Tables and Figures.
{"title":"Analytical Modeling of I-beam as a Sandwich Structure","authors":"K. Magnucki, J. Lewiński","doi":"10.24423/ENGTRANS.898.20180809","DOIUrl":"https://doi.org/10.24423/ENGTRANS.898.20180809","url":null,"abstract":"The paper is devoted to an analytical model of I-beam, with consideration of the shear effect. The model is based on the sandwich beam theory. The field displacements and strains are formulated with consideration of a nonlinear hypothesis of flat cross-section deformation of the beam. The governing differential equations for the I-beam are obtained based on the principle of stationary total potential energy. The shear effect of the beam is illustrated for the threepoint bending case. The analytical solution is compared to FEM numerical calculation. The results of the analysis are presented in Tables and Figures.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48344090","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 : 2018-07-26DOI: 10.24423/ENGTRANS.882.20180726
K. Magnucki, S. Milecki, J. Lewiński, P. Kȩdzia
The subject of the paper is a seven layer beam with foam cores. The structure of the beam is symmetrical. The beam is composed of the main core, two inner sheets, two second cores and two outer sheets. The main core and two face cores are metal and polyurethane foams, while the sheets are metal. The analytical model of the beam is developed. The displacement and strain fields are formulated with consideration of the Zig-Zag hypothesis of deformation of a flat cross-section of the beam. The governing differential equations for the seven layer beam are obtained based on the stationary total potential energy. The detailed studies are devoted to deflections and stresses of the beams under a uniformly distributed load. The influence of the foam type of cores on the deflections and stresses of the beam is analysed. Moreover, the numerical FEM-model of the beam is developed. The analytical solution is compared to numerical calculations – FEM studies (ABAQUS System and SolidWorks Simulation). The results of the analysis are presented in Tables and Figures.
{"title":"Bending of a Seven Layer Beam with Foam Cores","authors":"K. Magnucki, S. Milecki, J. Lewiński, P. Kȩdzia","doi":"10.24423/ENGTRANS.882.20180726","DOIUrl":"https://doi.org/10.24423/ENGTRANS.882.20180726","url":null,"abstract":"The subject of the paper is a seven layer beam with foam cores. The structure of the beam is symmetrical. The beam is composed of the main core, two inner sheets, two second cores and two outer sheets. The main core and two face cores are metal and polyurethane foams, while the sheets are metal. The analytical model of the beam is developed. The displacement and strain fields are formulated with consideration of the Zig-Zag hypothesis of deformation of a flat cross-section of the beam. The governing differential equations for the seven layer beam are obtained based on the stationary total potential energy. The detailed studies are devoted to deflections and stresses of the beams under a uniformly distributed load. The influence of the foam type of cores on the deflections and stresses of the beam is analysed. Moreover, the numerical FEM-model of the beam is developed. The analytical solution is compared to numerical calculations – FEM studies (ABAQUS System and SolidWorks Simulation). The results of the analysis are presented in Tables and Figures.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46595886","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 : 2018-07-26DOI: 10.24423/ENGTRANS.859.20180726
R. Selvamani, O. Makinde
In this paper, the influence of rotation on axisymmetric waves of a piezoelectric rod coated with a thin film is studied using constitutive form linear theory elasticity and piezo-electric equations. Potential functions are introduced to uncouple the equations of motion in radial and axial directions. The surface area of the rod is coated by a perfectly conducting material. The frequency equations are obtained for longitudinal and flexural modes of vibration and are studied numerically for PZT-4 ceramics. The computed non-dimensional frequency, phase velocity, relative frequency shift, electromechanical coupling and electric displacement are presented in the form of dispersion curves. This type of study is important in the construction of rotating sensors and gyroscope.
{"title":"Influence of Rotation on Transversely Isotropic Piezoelectric Rod Coated with a Thin Film","authors":"R. Selvamani, O. Makinde","doi":"10.24423/ENGTRANS.859.20180726","DOIUrl":"https://doi.org/10.24423/ENGTRANS.859.20180726","url":null,"abstract":"In this paper, the influence of rotation on axisymmetric waves of a piezoelectric rod coated with a thin film is studied using constitutive form linear theory elasticity and piezo-electric equations. Potential functions are introduced to uncouple the equations of motion in radial and axial directions. The surface area of the rod is coated by a perfectly conducting material. The frequency equations are obtained for longitudinal and flexural modes of vibration and are studied numerically for PZT-4 ceramics. The computed non-dimensional frequency, phase velocity, relative frequency shift, electromechanical coupling and electric displacement are presented in the form of dispersion curves. This type of study is important in the construction of \u0000rotating sensors and gyroscope.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47192318","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 : 2018-06-11DOI: 10.24423/ENGTRANS.876.20180611
Błażej Wojaczek, A. Katunin, J. Brol, K. Adamczyk
The wooden transmission tower of the Gliwice radiostation is the highest wooden construction around the world. Considering that it is in operation over 80 years it is necessary to properly maintain it to extend its residual life. In order to analyse the most critical elements of the tower as well as to plan the strategy of its maintenance, including repairs and replacements of wooden elements, it is necessary to analyse its deflection and stress distributions under possible loading scenarios. In this paper, the authors presented an overview of history and construction of the tower as well as presented the results of static and buckling numerical simulations to evaluate a condition and a margin of safety, and to find the critical structural elements of this construction. The 3D numerical analysis is performed for the wooden transmission tower of the Gliwice radiostation for the first time. The results of simulations presented in this study indicate acceptable condition of the tower, in particular the resulting stresses under the static loading or buckling are at the level of 18% of the critical stresses according to the assumed geometrical model. However, further studies are necessary to refine numerical model and consider secondary elements of the tower, wood imperfections and other factors that have significant influence on its integrity and safety.
{"title":"Numerical Simulation of Deflection and Stability of the Wooden Transmission Tower of Gliwice Radiostation","authors":"Błażej Wojaczek, A. Katunin, J. Brol, K. Adamczyk","doi":"10.24423/ENGTRANS.876.20180611","DOIUrl":"https://doi.org/10.24423/ENGTRANS.876.20180611","url":null,"abstract":"The wooden transmission tower of the Gliwice radiostation is the highest wooden construction around the world. Considering that it is in operation over 80 years it is necessary to properly maintain it to extend its residual life. In order to analyse the most critical elements of the tower as well as to plan the strategy of its maintenance, including repairs and replacements of wooden elements, it is necessary to analyse its deflection and stress distributions under possible loading scenarios. In this paper, the authors presented an overview of history and construction of the tower as well as presented the results of static and buckling numerical simulations to evaluate a condition and a margin of safety, and to find the critical structural elements of this construction. The 3D numerical analysis is performed for the wooden transmission tower of the Gliwice radiostation for the first time. The results of simulations presented in this study indicate acceptable condition of the tower, in particular the resulting stresses under the static loading or buckling are at the level of 18% of the critical stresses according to the assumed geometrical model. However, further studies are necessary to refine numerical model and consider secondary elements of the tower, wood imperfections and other factors that have significant influence on its integrity and safety.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42451362","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}
Following the increasing availability of DNA‐sequenced data, the genetic structure of populations can now be inferred and studied in unprecedented detail. Across social science, this innovation is shaping new bio‐social research agendas, attracting substantial investment in the collection of genetic, biological and social data for large population samples. Yet genetic samples are special because the precise populations that they represent are uncertain and ill‐defined. Unlike most social surveys, a genetic sample's representativeness of the population cannot be established by conventional procedures of statistical inference, and the implications for population‐wide generalisations about bio‐social phenomena are little understood. In this paper, we seek to address these problems by linking surname data to a censored and geographically uneven sample of DNA scans, collected for the People of the British Isles study. Based on a combination of global and local spatial correspondence measures, we identify eight regions in Great Britain that are most likely to represent the geography of genetic structure of Great Britain's long‐settled population. We discuss the implications of this regionalisation for bio‐social investigations. We conclude that, as the often highly selective collection of DNA and biomarkers becomes a more common practice, geography is crucial to understanding variation in genetic information within diverse populations.
{"title":"Regional surnames and genetic structure in Great Britain","authors":"Jens Kandt, J. Cheshire, P. Longley","doi":"10.1111/tran.12131","DOIUrl":"https://doi.org/10.1111/tran.12131","url":null,"abstract":"Following the increasing availability of DNA‐sequenced data, the genetic structure of populations can now be inferred and studied in unprecedented detail. Across social science, this innovation is shaping new bio‐social research agendas, attracting substantial investment in the collection of genetic, biological and social data for large population samples. Yet genetic samples are special because the precise populations that they represent are uncertain and ill‐defined. Unlike most social surveys, a genetic sample's representativeness of the population cannot be established by conventional procedures of statistical inference, and the implications for population‐wide generalisations about bio‐social phenomena are little understood. In this paper, we seek to address these problems by linking surname data to a censored and geographically uneven sample of DNA scans, collected for the People of the British Isles study. Based on a combination of global and local spatial correspondence measures, we identify eight regions in Great Britain that are most likely to represent the geography of genetic structure of Great Britain's long‐settled population. We discuss the implications of this regionalisation for bio‐social investigations. We conclude that, as the often highly selective collection of DNA and biomarkers becomes a more common practice, geography is crucial to understanding variation in genetic information within diverse populations.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82875092","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 : 1998-06-01DOI: 10.1111/J.0020-2754.1998.00193.X
A. Baker
"Military service in France during the nineteenth century removed many young men from their own localities for long periods. The widely accepted claim that few conscripts returned home after completing their period of service is based on little evidence. The paper examines the conscription classes of 1856 and 1891 in two cantons in the departement of Loir-et-Cher. In those cases, there was not a significant relationship between conscription and migration, nor between literacy and migration. Instead, migration of youths in their twenties was linked partly to prior experiences of migration but principally to their occupations."
{"title":"Military service and migration in nineteenth-century France: some evidence from Loir-et-Cher.","authors":"A. Baker","doi":"10.1111/J.0020-2754.1998.00193.X","DOIUrl":"https://doi.org/10.1111/J.0020-2754.1998.00193.X","url":null,"abstract":"\"Military service in France during the nineteenth century removed many young men from their own localities for long periods. The widely accepted claim that few conscripts returned home after completing their period of service is based on little evidence. The paper examines the conscription classes of 1856 and 1891 in two cantons in the departement of Loir-et-Cher. In those cases, there was not a significant relationship between conscription and migration, nor between literacy and migration. Instead, migration of youths in their twenties was linked partly to prior experiences of migration but principally to their occupations.\"","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90151369","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：