The problem of globally quadratic stability of switched nonlinear systems in block-triangular form under arbitrary switching is addressed. Under the assumption that all block-subsystems are zero input-to-state stable,...The problem of globally quadratic stability of switched nonlinear systems in block-triangular form under arbitrary switching is addressed. Under the assumption that all block-subsystems are zero input-to-state stable, a su?cient condition for the problem to be solvable ispresented. A common Lyapunov function is constructed iteratively by using the Lyapunov functionsof block-subsystems.展开更多
A commercial plasma immersion ion implanter has been designed and constructed to enhance the surface properties of parts and components used in aerospace applications. The implanter consists of a vacuum chamber, pumpi...A commercial plasma immersion ion implanter has been designed and constructed to enhance the surface properties of parts and components used in aerospace applications. The implanter consists of a vacuum chamber, pumping and gas inlet system, custom sample chuck, four sets of hotfilaments, threefiltered vacuum arc plasma sources, special high voltage modulator, as well as monitoring and control systems. Special attention has been paid to improve the uniformity of plasma in the chamber. The power modulator operates in both the pulse bunching and single pulse modes. The maximum pulse voltage output is 80kV, maximum pulse current is 60A, and repetition frequency is 50～500Hz. The target chuck has been specially designed for uniform implantation into multiple aerospace components with irregular geometries as well as effective sample cooling. An in situ temperature monitoring device comprising dual thermocouples has been developed. The instrument was installed in an aerospace company and has been operating reliably for a year. In addition to reporting some of the hardware innovations, data on the improvement of the lifetime of an aircraft hydraulic pump disk using a dual nitrogen treatment process m-2; 30～45kV are presented. This treatment protocol has been adopted as a standard production procedure in the factory.展开更多
Background Recent studies have revealed the important role of free radicals in renal damage induced by high energy shock waves (HESW) This study aimed at investigating the effects of Astragalus membranaceus , a...Background Recent studies have revealed the important role of free radicals in renal damage induced by high energy shock waves (HESW) This study aimed at investigating the effects of Astragalus membranaceus , a traditional Chinese medicinal herb, on free radical mediated HESW induced damage to renal tubules in a live rabbit model Methods Forty five healthy male New Zealand white rabbits were randomly divided into three groups: control group ( n =15), sham group ( n =15), and herb treated group ( n =15) Three days prior to HESW application, the controls received verapamil (0 4 mg/kg), the shams received physiological saline (20 ml), and the herb treated animals received Astragalus membranaceus (2 4 g/kg) intravenously HESW (1500 shocks, 18kV) was applied to the right kidneys of all anesthetized rabbits We measured superoxide dismutase (SOD) and malondialdehyde (MDA) levels before and after shock treatment in blood and kidney homogenates Histopathological changes were also observed Results MDA levels increased and SOD activity decreased significantly in the sham group ( P <0 05 for both) after shock treatment MDA levels showed a much less increase in the controls ( P <0 05) and did not increase to statistically significant levels in the group receiving Astragalus membranaceus ( P >0 05) SOD values were significantly higher in the controls than in the shams ( P <0 05) By contrast, SOD levels recovered rapidly in the rabbits receiving Astragalus membranaceus , reaching a nadir within 24 hours, and returning to baseline more quickly than in control and sham rabbits ( P <0 05) Histopathological examinations showed that renal tubular damage in the controls was less severe than in the shams, while damage in the Astragalus membranaceus group was even more mild, with rapid recovery in comparison with the controls Conclusion This study provides preliminary evidence indicating that Astragalus membranaceus has strong protective effects on free radical mediated renal tubular damage induced by HESW and that these effects are superior to the effects of verapamil展开更多
Mobile IP is the proposed standard for IP mobility support. When a MobileNode (MN) is far away from home, registration at its home agent can cause a long handoff delay thatleads to significant packet drop and throughp...Mobile IP is the proposed standard for IP mobility support. When a MobileNode (MN) is far away from home, registration at its home agent can cause a long handoff delay thatleads to significant packet drop and throughput reduction. In order to improve standard mobile IP,the mobility of MN has been divided into micro-mobility and macro-mobility. Some micro-mobilitymanagement protocols have been developed. We compare the performance between standard mobile IP(RFC2002, RFC3220, RFC3344) and micro-mobility management protocols and give some equations alongwith the analysis of calculating results.展开更多
基金Supported by Natural Science Foundation of P.R.China(60274009),the Foundation for Docto(r2a)lSpecial Branch by the Ministry of Eduction of P.R.China(20020145007),and Natural Science Foundation ofLiaoning Province(20032020)
文摘The problem of globally quadratic stability of switched nonlinear systems in block-triangular form under arbitrary switching is addressed. Under the assumption that all block-subsystems are zero input-to-state stable, a su?cient condition for the problem to be solvable ispresented. A common Lyapunov function is constructed iteratively by using the Lyapunov functionsof block-subsystems.
文摘A commercial plasma immersion ion implanter has been designed and constructed to enhance the surface properties of parts and components used in aerospace applications. The implanter consists of a vacuum chamber, pumping and gas inlet system, custom sample chuck, four sets of hotfilaments, threefiltered vacuum arc plasma sources, special high voltage modulator, as well as monitoring and control systems. Special attention has been paid to improve the uniformity of plasma in the chamber. The power modulator operates in both the pulse bunching and single pulse modes. The maximum pulse voltage output is 80kV, maximum pulse current is 60A, and repetition frequency is 50～500Hz. The target chuck has been specially designed for uniform implantation into multiple aerospace components with irregular geometries as well as effective sample cooling. An in situ temperature monitoring device comprising dual thermocouples has been developed. The instrument was installed in an aerospace company and has been operating reliably for a year. In addition to reporting some of the hardware innovations, data on the improvement of the lifetime of an aircraft hydraulic pump disk using a dual nitrogen treatment process m-2; 30～45kV are presented. This treatment protocol has been adopted as a standard production procedure in the factory.
基金ThisresearchwassupportedbytheScienceandTechnologyDevelopmentProjectFoundationofShaanxiProvince (No 2 0 0 1K11 G7)
文摘Background Recent studies have revealed the important role of free radicals in renal damage induced by high energy shock waves (HESW) This study aimed at investigating the effects of Astragalus membranaceus , a traditional Chinese medicinal herb, on free radical mediated HESW induced damage to renal tubules in a live rabbit model Methods Forty five healthy male New Zealand white rabbits were randomly divided into three groups: control group ( n =15), sham group ( n =15), and herb treated group ( n =15) Three days prior to HESW application, the controls received verapamil (0 4 mg/kg), the shams received physiological saline (20 ml), and the herb treated animals received Astragalus membranaceus (2 4 g/kg) intravenously HESW (1500 shocks, 18kV) was applied to the right kidneys of all anesthetized rabbits We measured superoxide dismutase (SOD) and malondialdehyde (MDA) levels before and after shock treatment in blood and kidney homogenates Histopathological changes were also observed Results MDA levels increased and SOD activity decreased significantly in the sham group ( P <0 05 for both) after shock treatment MDA levels showed a much less increase in the controls ( P <0 05) and did not increase to statistically significant levels in the group receiving Astragalus membranaceus ( P >0 05) SOD values were significantly higher in the controls than in the shams ( P <0 05) By contrast, SOD levels recovered rapidly in the rabbits receiving Astragalus membranaceus , reaching a nadir within 24 hours, and returning to baseline more quickly than in control and sham rabbits ( P <0 05) Histopathological examinations showed that renal tubular damage in the controls was less severe than in the shams, while damage in the Astragalus membranaceus group was even more mild, with rapid recovery in comparison with the controls Conclusion This study provides preliminary evidence indicating that Astragalus membranaceus has strong protective effects on free radical mediated renal tubular damage induced by HESW and that these effects are superior to the effects of verapamil
文摘Mobile IP is the proposed standard for IP mobility support. When a MobileNode (MN) is far away from home, registration at its home agent can cause a long handoff delay thatleads to significant packet drop and throughput reduction. In order to improve standard mobile IP,the mobility of MN has been divided into micro-mobility and macro-mobility. Some micro-mobilitymanagement protocols have been developed. We compare the performance between standard mobile IP(RFC2002, RFC3220, RFC3344) and micro-mobility management protocols and give some equations alongwith the analysis of calculating results.
