Carboxyl ion (COOH+) implantation was performed at 50 keV with different fluences for polypropylene. Hemocompatibility tests show that blood coagulation time and recalcification time of polypropylene were enhanced significantly with the increasing fluence. At the same time, the human endothelial cells grown on the surface of the implanted samples exhibited normal cellular growth and morphology. X-ray photoelectron spectroscopy and water contact angle analysis showed that COOH+ ion implantation rearranges chemical bonds and produces some new polar O-containing groups on the surface. The formation of polar functional groups, together with increase of roughness, induced an increase in hydrophilicity, which in turn improved the surface hemocompatibility of polypropylene.
{"title":"Effects of COOH+ ion implantation on hemocompatibility of polypropylene","authors":"Dejun Li, L. Niu","doi":"10.1360/02YE9076","DOIUrl":"https://doi.org/10.1360/02YE9076","url":null,"abstract":"Carboxyl ion (COOH+) implantation was performed at 50 keV with different fluences for polypropylene. Hemocompatibility tests show that blood coagulation time and recalcification time of polypropylene were enhanced significantly with the increasing fluence. At the same time, the human endothelial cells grown on the surface of the implanted samples exhibited normal cellular growth and morphology. X-ray photoelectron spectroscopy and water contact angle analysis showed that COOH+ ion implantation rearranges chemical bonds and produces some new polar O-containing groups on the surface. The formation of polar functional groups, together with increase of roughness, induced an increase in hydrophilicity, which in turn improved the surface hemocompatibility of polypropylene.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121696217","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}
This paper analyzes the differential topological characteristics of the dynamic security region (DSR) on injection space of electrical power system by differential topology theories. It is shown that the boundary of the DSR on injection space has no suspension and is compact, and there are no holes inside the DSR defined based on controlling unstable equilibrium point (UEP) method. The 10-generator, 39-bus New England Test System, is taken as an example to show these characteristics of the DSR on injection space.
{"title":"Differential topological characteristics of the DSR on injection space of electrical power system","authors":"Yixin Yu, Yuan Zeng, Fei Feng","doi":"10.1360/02YE9066","DOIUrl":"https://doi.org/10.1360/02YE9066","url":null,"abstract":"This paper analyzes the differential topological characteristics of the dynamic security region (DSR) on injection space of electrical power system by differential topology theories. It is shown that the boundary of the DSR on injection space has no suspension and is compact, and there are no holes inside the DSR defined based on controlling unstable equilibrium point (UEP) method. The 10-generator, 39-bus New England Test System, is taken as an example to show these characteristics of the DSR on injection space.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129818381","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}
Yusheng He, Haiyang Li, A. He, Shunzhou Li, Chunguang Li, Xueqiang Zhang, Taiping Zhang, Lingwen Yan, Wenxiu Zhu, Yuan Zhou, Jingtao Liang, Jia-Sheng Hong, Lancaster M. J.
The first HTS front-end subsystem for wireless base station in China was developed. This demonstration system, which aims at the application in GSM 1800 mobile communication base station, consists of a single RF path, i.e. one filter and one LNA, integrated with the pulse tube cooler. The subsystem works at a pass band of 1710–1785 MHz with a gain of 18 dB and at a temperature of 70 K. The accomplishment of such a demonstration subsystem can boost the development of HTS commercial subsystem.
{"title":"HTS filter and front-end subsystem for GSM1800 wireless base station","authors":"Yusheng He, Haiyang Li, A. He, Shunzhou Li, Chunguang Li, Xueqiang Zhang, Taiping Zhang, Lingwen Yan, Wenxiu Zhu, Yuan Zhou, Jingtao Liang, Jia-Sheng Hong, Lancaster M. J.","doi":"10.1360/02YE9072","DOIUrl":"https://doi.org/10.1360/02YE9072","url":null,"abstract":"The first HTS front-end subsystem for wireless base station in China was developed. This demonstration system, which aims at the application in GSM 1800 mobile communication base station, consists of a single RF path, i.e. one filter and one LNA, integrated with the pulse tube cooler. The subsystem works at a pass band of 1710–1785 MHz with a gain of 18 dB and at a temperature of 70 K. The accomplishment of such a demonstration subsystem can boost the development of HTS commercial subsystem.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132120233","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}
Qiang Xu, Yedong He, Deren Wang, H. Qi, Zhengwei Li, Wei Gao
A new technique—series electro-pulse discharge (SEPD)—was developed as a surface coating process. In this process, both positive and negative poles of a pulse power were used as the depositing electrodes and the substrate alloy was used as an induction electrode. The physical process for such SEPD was tested by measuring the relationship between the discharge voltages and gaps in a pin-plate-pin system. Microcrystalline Ni20Cr alloy coatings and oxidedispersed Ni20Cr alloy coatings were prepared on Ni20Cr alloy surface by using a vibrating SEPD device. Oxidation at 950°C in ambient air showed that the microcrystalline Ni20Cr alloy coatings greatly improved the oxidation resistance of the substrate alloy. The addition of dispersed Y2O3 nano-particles into the microcrystalline coatings was found to further reduce the oxidation rate and enhance the oxide spallation resistance.
{"title":"Microcrystalline coatings deposited by series double-pole electro-pulse discharge and its high-temperature oxidation behavior","authors":"Qiang Xu, Yedong He, Deren Wang, H. Qi, Zhengwei Li, Wei Gao","doi":"10.1360/02YE9055","DOIUrl":"https://doi.org/10.1360/02YE9055","url":null,"abstract":"A new technique—series electro-pulse discharge (SEPD)—was developed as a surface coating process. In this process, both positive and negative poles of a pulse power were used as the depositing electrodes and the substrate alloy was used as an induction electrode. The physical process for such SEPD was tested by measuring the relationship between the discharge voltages and gaps in a pin-plate-pin system. Microcrystalline Ni20Cr alloy coatings and oxidedispersed Ni20Cr alloy coatings were prepared on Ni20Cr alloy surface by using a vibrating SEPD device. Oxidation at 950°C in ambient air showed that the microcrystalline Ni20Cr alloy coatings greatly improved the oxidation resistance of the substrate alloy. The addition of dispersed Y2O3 nano-particles into the microcrystalline coatings was found to further reduce the oxidation rate and enhance the oxide spallation resistance.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121175010","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}
Binghong Zhou, Qiusheng Liu, L. Hu, Yonglong Yao, Wen-rui Hu
In 1999, the space experiments on the Marangoni convection and thermocapillary convection in a system of two immiscible liquid layers in microgravity environment were conducted on board the Chinese scientific satellite SJ-5. A new system of two-layer liquids such as FC-70 liquid and paraffin was used successfully, with the paraffin melted in the space. Two different test-cells are subjected to a temperature gradient perpendicular or parallel to the interface to study the Marangoni convection and thermocapillary convection, respectively. The experimental data obtained in the first Chinese space experiment of fluid are presented. Two-dimensional numerical simulations of thermocapillary convections are carried out using SIMPLEC method. A reasonable agreement between the experimental investigation and the numerical results is obtained.
{"title":"Space experiments of thermocapillary convection in two-liquid layers","authors":"Binghong Zhou, Qiusheng Liu, L. Hu, Yonglong Yao, Wen-rui Hu","doi":"10.1360/02YE9063","DOIUrl":"https://doi.org/10.1360/02YE9063","url":null,"abstract":"In 1999, the space experiments on the Marangoni convection and thermocapillary convection in a system of two immiscible liquid layers in microgravity environment were conducted on board the Chinese scientific satellite SJ-5. A new system of two-layer liquids such as FC-70 liquid and paraffin was used successfully, with the paraffin melted in the space. Two different test-cells are subjected to a temperature gradient perpendicular or parallel to the interface to study the Marangoni convection and thermocapillary convection, respectively. The experimental data obtained in the first Chinese space experiment of fluid are presented. Two-dimensional numerical simulations of thermocapillary convections are carried out using SIMPLEC method. A reasonable agreement between the experimental investigation and the numerical results is obtained.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133692689","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}
Tian Huang, Ya Li, Guobao Tang, Siwei Li, Xingyu Zhao, Whitehouse David. J., Chetewyn Derek G., Xian-Ming Liu
This paper presents an error modeling methodology that enables the tolerance design, assembly and kinematic calibration of a class of 3-DOF parallel kinematic machines with parallelogram struts to be integrated into a unified framework. The error mapping function is formulated to identify the source errors affecting the uncompensable pose error. The sensitivity analysis in the sense of statistics is also carried out to investigate the influences of source errors on the pose accuracy. An assembly process that can effectively minimize the uncompensable pose error is proposed as one of the results of this investigation.
{"title":"Error modeling, sensitivity analysis and assembly process of a class of 3-DOF parallel kinematic machines with parallelogram struts","authors":"Tian Huang, Ya Li, Guobao Tang, Siwei Li, Xingyu Zhao, Whitehouse David. J., Chetewyn Derek G., Xian-Ming Liu","doi":"10.1360/02YE9054","DOIUrl":"https://doi.org/10.1360/02YE9054","url":null,"abstract":"This paper presents an error modeling methodology that enables the tolerance design, assembly and kinematic calibration of a class of 3-DOF parallel kinematic machines with parallelogram struts to be integrated into a unified framework. The error mapping function is formulated to identify the source errors affecting the uncompensable pose error. The sensitivity analysis in the sense of statistics is also carried out to investigate the influences of source errors on the pose accuracy. An assembly process that can effectively minimize the uncompensable pose error is proposed as one of the results of this investigation.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128887538","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}
Based on the multipole expansion theory of the potential, a satisfactory interpretation is put forward of the exact nature of the approximations of asymptotic boundary condition (called the ABC) techniques for the numerical solutions of open-boundary static electromagnetic-field problems, and a definite physical meaning is bestowed on ABC, which provide a powerful theoretical background for laying down the operating rules and the key to the derivation of asymptotic boundary conditions. This paper is also intended to reveal the shortcomings of the conventional higher-order ABC, and at the same time to give the concept of a new type of higher-order ABC, and to present a somewhat different formulation of the new nth-order ABC. In order to test its feasibility, several simple problems of electrostatic potentials are analyzed. The results are found to be much better than those of conventional higher-order ABCs.
{"title":"A theoretical study of asymptotic boundary conditions for the numerical solutions of open-boundary static electromagnetic-field problems","authors":"Xikui Ma, Shejiao Han","doi":"10.1360/02YE9062","DOIUrl":"https://doi.org/10.1360/02YE9062","url":null,"abstract":"Based on the multipole expansion theory of the potential, a satisfactory interpretation is put forward of the exact nature of the approximations of asymptotic boundary condition (called the ABC) techniques for the numerical solutions of open-boundary static electromagnetic-field problems, and a definite physical meaning is bestowed on ABC, which provide a powerful theoretical background for laying down the operating rules and the key to the derivation of asymptotic boundary conditions. This paper is also intended to reveal the shortcomings of the conventional higher-order ABC, and at the same time to give the concept of a new type of higher-order ABC, and to present a somewhat different formulation of the new nth-order ABC. In order to test its feasibility, several simple problems of electrostatic potentials are analyzed. The results are found to be much better than those of conventional higher-order ABCs.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122175575","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}
Hongwei Zhu, Xuesong Li, Lijie Ci, Cai-lu Xu, Z. Mao, Ji Liang, De-hai Wu
Hydrogen storage under moderate pressure (∼10 MPa) and ambient temperature (∼25°C) in multi-walled carbon nanotubes (MWNTs) prepared by the floating catalyst method is investigated. The capacity of hydrogen adsorption is evaluated based on both the nanotubes diameter and morphology. Indirect evidence indicates that hydrogen adsorption not only occurs on tube surface and interiors, but also in tube interlayers. The results show that the floating catalytic carbon nanotubes might be a candidate hydrogen storage material for fuel cell electric vehicles.
{"title":"Storage of hydrogen in floating catalytic carbon nanotubes after graphitizing","authors":"Hongwei Zhu, Xuesong Li, Lijie Ci, Cai-lu Xu, Z. Mao, Ji Liang, De-hai Wu","doi":"10.1360/02YE9059","DOIUrl":"https://doi.org/10.1360/02YE9059","url":null,"abstract":"Hydrogen storage under moderate pressure (∼10 MPa) and ambient temperature (∼25°C) in multi-walled carbon nanotubes (MWNTs) prepared by the floating catalyst method is investigated. The capacity of hydrogen adsorption is evaluated based on both the nanotubes diameter and morphology. Indirect evidence indicates that hydrogen adsorption not only occurs on tube surface and interiors, but also in tube interlayers. The results show that the floating catalytic carbon nanotubes might be a candidate hydrogen storage material for fuel cell electric vehicles.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117276103","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}
Based on the understandings of the relationship between the river runoff and the primary functions of the Yellow River, this paper advances the concept of functional no-flow event that is different from the zero-discharge event occurring in the river. Factors reflecting the characteristics of functional no-flow events were analyzed and the criteria describing severity levels of the events were given from the cluster analysis with the measured data from 1950 to 1999. The results show that the severity level is subject to the critical water demand for river ecosystem protection. Using two critical water use demand scenarios for the Yellow River proposed by the authors and the Yellow River Water Conservancy Commission, different severity levels of functional no-flow events are identified. In addition, the differences between the zero-discharge and the functional no-flow events are discussed.
{"title":"Functional no-flow events and their identification in the Lower Yellow River","authors":"J. Ni, Zhenghan Qian","doi":"10.1360/02YE9052","DOIUrl":"https://doi.org/10.1360/02YE9052","url":null,"abstract":"Based on the understandings of the relationship between the river runoff and the primary functions of the Yellow River, this paper advances the concept of functional no-flow event that is different from the zero-discharge event occurring in the river. Factors reflecting the characteristics of functional no-flow events were analyzed and the criteria describing severity levels of the events were given from the cluster analysis with the measured data from 1950 to 1999. The results show that the severity level is subject to the critical water demand for river ecosystem protection. Using two critical water use demand scenarios for the Yellow River proposed by the authors and the Yellow River Water Conservancy Commission, different severity levels of functional no-flow events are identified. In addition, the differences between the zero-discharge and the functional no-flow events are discussed.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133565280","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}
Modeling method was used to research the recovering law of inner cavity-type cracks during the processes of high-temperature plastic deformation. It was found that the self-recovering of cavity-type fault was similar to the self-healing of wound of skin and fracture. The self-recovering process of cavity-type fault was investigated according to the rule of self-healing of wound in human body. The recrystallization mechanism of self-recovering of cavity-type fault was discovered. A new method is presented to study the self-recovering mechanism of cavity-type cracks.
{"title":"Mimic-biology research on self-recovering mechanism of cavity-type crack","authors":"Chaolong Yuan, Y. Zhong, Q. Ma, Qixiang Cao","doi":"10.1360/02YE9061","DOIUrl":"https://doi.org/10.1360/02YE9061","url":null,"abstract":"Modeling method was used to research the recovering law of inner cavity-type cracks during the processes of high-temperature plastic deformation. It was found that the self-recovering of cavity-type fault was similar to the self-healing of wound of skin and fracture. The self-recovering process of cavity-type fault was investigated according to the rule of self-healing of wound in human body. The recrystallization mechanism of self-recovering of cavity-type fault was discovered. A new method is presented to study the self-recovering mechanism of cavity-type cracks.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125050290","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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