Advances in Mechanical Engineering最新文献_第3页

A study on the actual heat leak of a cryogenic vessel during storage 关于低温容器在储存过程中实际热量泄漏的研究

Advances in Mechanical Engineering Pub Date : 2024-02-01 DOI: 10.1177/16878132241229313

Zhengqing Li, Xiaojun Wang, Sheng-sheng Yang, Xianhu Han, Yuhong Cai

{"title":"A study on the actual heat leak of a cryogenic vessel during storage","authors":"Zhengqing Li, Xiaojun Wang, Sheng-sheng Yang, Xianhu Han, Yuhong Cai","doi":"10.1177/16878132241229313","DOIUrl":"https://doi.org/10.1177/16878132241229313","url":null,"abstract":"In the traditional method, as the loss product and gas are considered to be saturated, the heat leak of a cryogenic vessel is the latent heat of loss product. However, the temperature of loss product and gas exceeds the saturated temperature as measured in tests. Therefore, a portion of the heat leak is absorbed by the loss product when it diffuses into the gas phase of a cryogenic vessel in the storage process. In this study, the energy equations of the gas and liquid are established in cryogenic vessels during storage to investigate the actual heat leak of a cryogenic vessel in a storage process by considering the temperature distribution of the gas. Then, an experiment was conducted to demonstrate that the actual heat leak of a cryogenic vessel contains not only the latent heat but also the enthalpy change of the loss product, which is produced as it diffused into the gas phase. The results showed that the enthalpy change increased as the liquid level decreased and was critical for determining the actual heat leak in cryogenic vessels in the storage process, with a ratio of approximately 12% to the latent heat when the liquid level ratio is 85%.","PeriodicalId":502561,"journal":{"name":"Advances in Mechanical Engineering","volume":"78 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139888077","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}

引用次数: 0

Experimental research on effects of influence factors on the axial cutter vibration, cutting forces and the sugarcane cutting quality under complicated excitations 复杂激励条件下影响因素对轴向切刀振动、切削力和甘蔗切割质量影响的实验研究

Advances in Mechanical Engineering Pub Date : 2024-02-01 DOI: 10.1177/16878132231221919

Hanning Mo, Shaochun Ma, Zhimin Huang, Shangping Li, Chen Qiu

{"title":"Experimental research on effects of influence factors on the axial cutter vibration, cutting forces and the sugarcane cutting quality under complicated excitations","authors":"Hanning Mo, Shaochun Ma, Zhimin Huang, Shangping Li, Chen Qiu","doi":"10.1177/16878132231221919","DOIUrl":"https://doi.org/10.1177/16878132231221919","url":null,"abstract":"The sugarcane field excitation, the engine excitation and reaction forces acting on cutters constitute complicated excitations of sugarcane harvesters. Axial cutter vibration displacement measuring and sugarcane cutting experiments were done on a self-developed sugarcane harvester experiment platform (SHEP) with complicated excitations simulated through a simulated sugarcane field exciter and an actuating engine. Effects of the sugarcane field excitation, the engine excitation and cutting parameters on the axial cutter vibration, three-directional cutting forces and the sugarcane cutting quality (SCQ) were studied through single-factor and orthogonal experiments. Effects of the axial cutter vibration on three-directional cutting forces and those of these two influence factors on the SCQ were also studied. Significance levels of effects in the sugarcane cutting process form high to low are as follow, the sugarcane field excitation, the cutter rotating speed, the engine excitation, the cutter installing angle, the sugarcane harvester moving speed. The axial cutter vibration has a directly and highly significant monotonic negative correlated effect on the SCQ. For the best SCQ, the cutter rotating speed is 700 r/min, the sugarcane harvester moving speed is 0.6 m/s and the cutter installing angle is 8°, providing a reference for setting cutting parameters of sugarcane harvesters with a good SCQ.","PeriodicalId":502561,"journal":{"name":"Advances in Mechanical Engineering","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139889357","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}

引用次数: 0

A combined CFD-based simulation and experimental study of particle dispersion in a high-concentration airtight space under unorganized airflow 基于 CFD 的无组织气流条件下高浓度密闭空间中颗粒扩散的模拟与实验联合研究

Advances in Mechanical Engineering Pub Date : 2024-02-01 DOI: 10.1177/16878132231221556

Xiaonan Li, Tianpeng Li, Tong Xu, Ran Zhao, Xinbao Gao, Zhaolong Xuan

{"title":"A combined CFD-based simulation and experimental study of particle dispersion in a high-concentration airtight space under unorganized airflow","authors":"Xiaonan Li, Tianpeng Li, Tong Xu, Ran Zhao, Xinbao Gao, Zhaolong Xuan","doi":"10.1177/16878132231221556","DOIUrl":"https://doi.org/10.1177/16878132231221556","url":null,"abstract":"It is significant to obtain the particle distribution data for workpiece processing and industrial protection strategies. To simulate the particle dispersion in a high-concentration airtight space under unorganized airflow, a CFD-based simulation and experimental were utilized in this study. The proposed method works in three steps. The first step is to use Stokes-MRF-Fan-CFD model to simplify the distribution of high-concentration particles calculation to the dispersion state of the gas components. The second step is to compute the airflow patterns and dispersion of particles. The third step is to prove the feasibility of Stokes-MRF-Fan-CFD model. The results of this model in particle dispersion show ±200 mg·m−3 of absolute error, ±20% of relative error, and 88.5747 grade of simulation accuracy. And the results of particle concentration distribution can be mutually confirmed with the streamline and velocity vector distribution in the airtight space, providing a promising and innovative model for the particle dispersion in a high-concentration airtight space under unorganized airflow.","PeriodicalId":502561,"journal":{"name":"Advances in Mechanical Engineering","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139890585","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}

引用次数: 0

Theoretical analysis of vibration characteristics of high-speed cylindrical roller bearing with groove elastic supports 带沟槽弹性支承的高速圆柱滚子轴承振动特性的理论分析

Advances in Mechanical Engineering Pub Date : 2024-02-01 DOI: 10.1177/16878132241227111

Xue Sun, Yanhong Jiang, Shiliang Liu, Jun Xu, Wenhu Zhang

{"title":"Theoretical analysis of vibration characteristics of high-speed cylindrical roller bearing with groove elastic supports","authors":"Xue Sun, Yanhong Jiang, Shiliang Liu, Jun Xu, Wenhu Zhang","doi":"10.1177/16878132241227111","DOIUrl":"https://doi.org/10.1177/16878132241227111","url":null,"abstract":"As a necessary support system of high-speed rotor system, the roller bearing with elastic support’s vibration characteristics directly affect the stability and safety of rotor system. At this point, the theoretical analysis of bearing performance under the assumption of rigid ring is obviously no longer applicable. In this paper, considering the elastic deformation of both cylindrical roller bearing outer ring and the groove elastic support, the dynamic differential equations of cylindrical roller bearing with the elastic support are established on the basis of rolling bearing dynamics, and the bearing’s vibration under different working conditions is analyzed. The theoretical analysis results show that the groove elastic support can effectively reduce the radial vibration of cylindrical roller bearing under high speed and large radial load. And the experimental results show that the test’s vibration is consistent with the simulation’s vibration, which proves the reliability of the dynamic model of cylindrical roller bearing with the groove elastic support proposed in this paper. This research gives a new method for improving the dynamic characteristics of high-speed cylindrical roller bearings, and the model presented in this paper provides a theoretical basis for the design and manufacture of cylindrical roller bearing with elastic support.","PeriodicalId":502561,"journal":{"name":"Advances in Mechanical Engineering","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139822669","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}

引用次数: 0

A study on the actual heat leak of a cryogenic vessel during storage 关于低温容器在储存过程中实际热量泄漏的研究

Advances in Mechanical Engineering Pub Date : 2024-02-01 DOI: 10.1177/16878132241229313

Zhengqing Li, Xiaojun Wang, Sheng-sheng Yang, Xianhu Han, Yuhong Cai

{"title":"A study on the actual heat leak of a cryogenic vessel during storage","authors":"Zhengqing Li, Xiaojun Wang, Sheng-sheng Yang, Xianhu Han, Yuhong Cai","doi":"10.1177/16878132241229313","DOIUrl":"https://doi.org/10.1177/16878132241229313","url":null,"abstract":"In the traditional method, as the loss product and gas are considered to be saturated, the heat leak of a cryogenic vessel is the latent heat of loss product. However, the temperature of loss product and gas exceeds the saturated temperature as measured in tests. Therefore, a portion of the heat leak is absorbed by the loss product when it diffuses into the gas phase of a cryogenic vessel in the storage process. In this study, the energy equations of the gas and liquid are established in cryogenic vessels during storage to investigate the actual heat leak of a cryogenic vessel in a storage process by considering the temperature distribution of the gas. Then, an experiment was conducted to demonstrate that the actual heat leak of a cryogenic vessel contains not only the latent heat but also the enthalpy change of the loss product, which is produced as it diffused into the gas phase. The results showed that the enthalpy change increased as the liquid level decreased and was critical for determining the actual heat leak in cryogenic vessels in the storage process, with a ratio of approximately 12% to the latent heat when the liquid level ratio is 85%.","PeriodicalId":502561,"journal":{"name":"Advances in Mechanical Engineering","volume":"46 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139828293","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}

引用次数: 0

A novel reliability analysis methodology based on IPSO-MCopula model for gears with multiple failure modes 基于 IPSO-MCopula 模型的新型齿轮多失效模式可靠性分析方法

Advances in Mechanical Engineering Pub Date : 2024-02-01 DOI: 10.1177/16878132241228194

E. Xia, FuPing Zhou, Wang Kun-Chieh, Chunrong Wang, Gao Hao

{"title":"A novel reliability analysis methodology based on IPSO-MCopula model for gears with multiple failure modes","authors":"E. Xia, FuPing Zhou, Wang Kun-Chieh, Chunrong Wang, Gao Hao","doi":"10.1177/16878132241228194","DOIUrl":"https://doi.org/10.1177/16878132241228194","url":null,"abstract":"In order to accurately and quickly predict the failure probability of gears with multiple failure modes, a novel reliability analysis methodology based on the mixed Copula (MCopula) function model is proposed to deal with the complex correlation among different failure functions. Firstly, we construct a novel MCopula model based on three famous Copula functions: Gumbel Copula, Clayton Copula, and Frank Copula functions. Secondly, we use and improve the particle swarm optimization (PSO) method to optimally calculate the weight coefficients in the proposed MCopula model. Thirdly, the maximum likelihood estimation (MLE) method is adopted to estimate related parameters in the proposed MCopula model. Finally, we verify the proposed reliability analysis methodology with a standard life-prediction case of a strut system and a practical life-problem case of a gear pair system. Comparison results of both cases show that, by using the proposed methodology, the failure probability of a gear pair system with multiple failure correlations can be quickly calculated through a small number of samples and can be estimated as accurately as that by the Monte Carlo scheme. Consequently, our proposed novel methodology successfully analyzes the reliability problems for a gear pair system with multiple failure modes. The proposed methodology can be further applied to solve the reliability problem for other machine parts.","PeriodicalId":502561,"journal":{"name":"Advances in Mechanical Engineering","volume":"108 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139817004","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}

引用次数: 0

Research on noise reduction of drive axle hypoid gear based on tooth surface mismatch modification 基于齿面错位修正的驱动桥准二齿轮降噪研究

Advances in Mechanical Engineering Pub Date : 2024-02-01 DOI: 10.1177/16878132241228195

Shaowu Nie, Jinyu Chen, Shaohang Liu

{"title":"Research on noise reduction of drive axle hypoid gear based on tooth surface mismatch modification","authors":"Shaowu Nie, Jinyu Chen, Shaohang Liu","doi":"10.1177/16878132241228195","DOIUrl":"https://doi.org/10.1177/16878132241228195","url":null,"abstract":"In order to reduce the transmission noise of drive axle hypoid gear, a method of tooth surface mismatch modification was proposed. Firstly, on the basis of establishing the grinding mathematical model of hypoid gear with cutter tilt, the theoretical tooth surface equation was derived, and the numerical tooth surface was calculated by dividing the grid points on tooth surface. Secondly, the pinion tooth surface which was full conjugated with gear tooth surface was constructed, and the tooth surface mismatch topography was established and decomposed into the first order and second order mismatch coefficients. According to the modification requirements, the pinion target surface was constructed by modifying the tooth surface mismatch coefficients, and the pinion modified machine setting parameters were acquired by establishing the pinion processing parameters corrected mathematical model. Finally, the loaded tooth contact analysis with finite element simulation and drive axle NVH (Noise, Vibration, Harshness) simulation were carried out for a pair of hypoid gear, therefore the loaded tooth contact areas, transmission errors curves, and noise simulation curves were obtained, and the simulation results show that after modification the tooth contact stress, loaded transmission errors amplitude, and NVH simulation curves value are all reduced. The road test results indicate that the drive axle hypoid gear howling phenomenon under the high speed operation can be eliminated, so the effectiveness of tooth surface modification method and NVH simulation method were verified.","PeriodicalId":502561,"journal":{"name":"Advances in Mechanical Engineering","volume":"54 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139827462","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}

引用次数: 0

Theoretical analysis of vibration characteristics of high-speed cylindrical roller bearing with groove elastic supports 带沟槽弹性支承的高速圆柱滚子轴承振动特性的理论分析

Advances in Mechanical Engineering Pub Date : 2024-02-01 DOI: 10.1177/16878132241227111

Xue Sun, Yanhong Jiang, Shiliang Liu, Jun Xu, Wenhu Zhang

{"title":"Theoretical analysis of vibration characteristics of high-speed cylindrical roller bearing with groove elastic supports","authors":"Xue Sun, Yanhong Jiang, Shiliang Liu, Jun Xu, Wenhu Zhang","doi":"10.1177/16878132241227111","DOIUrl":"https://doi.org/10.1177/16878132241227111","url":null,"abstract":"As a necessary support system of high-speed rotor system, the roller bearing with elastic support’s vibration characteristics directly affect the stability and safety of rotor system. At this point, the theoretical analysis of bearing performance under the assumption of rigid ring is obviously no longer applicable. In this paper, considering the elastic deformation of both cylindrical roller bearing outer ring and the groove elastic support, the dynamic differential equations of cylindrical roller bearing with the elastic support are established on the basis of rolling bearing dynamics, and the bearing’s vibration under different working conditions is analyzed. The theoretical analysis results show that the groove elastic support can effectively reduce the radial vibration of cylindrical roller bearing under high speed and large radial load. And the experimental results show that the test’s vibration is consistent with the simulation’s vibration, which proves the reliability of the dynamic model of cylindrical roller bearing with the groove elastic support proposed in this paper. This research gives a new method for improving the dynamic characteristics of high-speed cylindrical roller bearings, and the model presented in this paper provides a theoretical basis for the design and manufacture of cylindrical roller bearing with elastic support.","PeriodicalId":502561,"journal":{"name":"Advances in Mechanical Engineering","volume":"25 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139882535","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}

引用次数: 0

Improved analytical model for calculating mesh stiffness and transmission error of helical gears considering root curve: Theoretical analysis and experiments 考虑根曲线的斜齿轮啮合刚度和传动误差的改进分析模型：理论分析和实验

Advances in Mechanical Engineering Pub Date : 2024-02-01 DOI: 10.1177/16878132241228196

Ziqian Liu, Yanjun Jiang, Ruitian Luo, Yangda Wu, Jiaopeng Huang, Nan Feng, Kui Li

{"title":"Improved analytical model for calculating mesh stiffness and transmission error of helical gears considering root curve: Theoretical analysis and experiments","authors":"Ziqian Liu, Yanjun Jiang, Ruitian Luo, Yangda Wu, Jiaopeng Huang, Nan Feng, Kui Li","doi":"10.1177/16878132241228196","DOIUrl":"https://doi.org/10.1177/16878132241228196","url":null,"abstract":"A modified algorithm is proposed in this study to correct time-varying mesh stiffness (TVMS) and transmission error (TE) in helical gears considering tooth root transition curve. The parametric model of helical gear is established by using the meshing principle of helical gear and hob in order to obtain the accurate tooth root transition curve. Moreover, a TE test rig is set up to compare the theoretical and experimental results. The results of the improved algorithm are very similar to the experimental results compared to the traditional model, and the relative error of TE is also small. In this study, the effect of multi-parameters (e.g. pressure angle, meshing position, transverse contact ratio, and overlap ratio) on TE are investigated by comparing theory with experimental analysis. Through the analysis of parameters, it has been established that an elevation in pressure angle leads to a decrease in TE, followed by an increase. In the event that the meshing position is situated closer to the nodal point, the TE slightly decreases. Moreover, as the transverse contact ratio and overlap ratio increase, the TVMS increases, while the TE decreases. When the overlap ratio approaches an odd multiple of 0.5, the TE displays a significant peak.","PeriodicalId":502561,"journal":{"name":"Advances in Mechanical Engineering","volume":"401 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139826024","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}

引用次数: 0

Experimental research on effects of influence factors on the axial cutter vibration, cutting forces and the sugarcane cutting quality under complicated excitations 复杂激励条件下影响因素对轴向切刀振动、切削力和甘蔗切割质量影响的实验研究

Advances in Mechanical Engineering Pub Date : 2024-02-01 DOI: 10.1177/16878132231221919

Hanning Mo, Shaochun Ma, Zhimin Huang, Shangping Li, Chen Qiu

{"title":"Experimental research on effects of influence factors on the axial cutter vibration, cutting forces and the sugarcane cutting quality under complicated excitations","authors":"Hanning Mo, Shaochun Ma, Zhimin Huang, Shangping Li, Chen Qiu","doi":"10.1177/16878132231221919","DOIUrl":"https://doi.org/10.1177/16878132231221919","url":null,"abstract":"The sugarcane field excitation, the engine excitation and reaction forces acting on cutters constitute complicated excitations of sugarcane harvesters. Axial cutter vibration displacement measuring and sugarcane cutting experiments were done on a self-developed sugarcane harvester experiment platform (SHEP) with complicated excitations simulated through a simulated sugarcane field exciter and an actuating engine. Effects of the sugarcane field excitation, the engine excitation and cutting parameters on the axial cutter vibration, three-directional cutting forces and the sugarcane cutting quality (SCQ) were studied through single-factor and orthogonal experiments. Effects of the axial cutter vibration on three-directional cutting forces and those of these two influence factors on the SCQ were also studied. Significance levels of effects in the sugarcane cutting process form high to low are as follow, the sugarcane field excitation, the cutter rotating speed, the engine excitation, the cutter installing angle, the sugarcane harvester moving speed. The axial cutter vibration has a directly and highly significant monotonic negative correlated effect on the SCQ. For the best SCQ, the cutter rotating speed is 700 r/min, the sugarcane harvester moving speed is 0.6 m/s and the cutter installing angle is 8°, providing a reference for setting cutting parameters of sugarcane harvesters with a good SCQ.","PeriodicalId":502561,"journal":{"name":"Advances in Mechanical Engineering","volume":"78 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139829506","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}

引用次数: 0