电力变压器匝间故障将导致绝缘击穿,甚至造成整个电网事故的发生,为此,应用在线频率响应分析法检测变压器绕组变形。通过安装于变压器套管表面的非侵入式电容传感器（NICS）将测试信号通过高压套管注入变压器绕组从而实现了绕组变形的...电力变压器匝间故障将导致绝缘击穿,甚至造成整个电网事故的发生,为此,应用在线频率响应分析法检测变压器绕组变形。通过安装于变压器套管表面的非侵入式电容传感器（NICS）将测试信号通过高压套管注入变压器绕组从而实现了绕组变形的在线监测。开发了基于脉冲信号注入法的变压器绕组变形在线监测系统。着重阐述了测试信号的选择,在线信号的注入,保护电路的设计。分析了信号源和采样频率对频响特性测试结果的影响。对一台型号为35 k VA/10 k V/400 V的配电变压器进行测试,并与安捷伦频谱网络分析仪4395A的测试结果进行对比发现,在0~5 MHz频率范围内,两条频响曲线的相关系数为0.955 3。结果表明,该系统能在在线状态下准确、快速地获取变压器绕组数10 MHz内的频响特性。监测系统具有较高的灵敏度和重复性,能有效检测变压器绕组变形。展开更多
Genetic transformation of embryogenic suspension cultures of sweetpotato cv. Lizixiang was conducted by using Agrobacterium tumefaciens strain A208SE harboring the binary vectors pROA93 with β-glucronidase(GUS)and ne...Genetic transformation of embryogenic suspension cultures of sweetpotato cv. Lizixiang was conducted by using Agrobacterium tumefaciens strain A208SE harboring the binary vectors pROA93 with β-glucronidase(GUS)and neomycin phosphotransferase(NPTⅡ)genes. The results indicated that embryogenic suspension cultures precultured for 1 - 3 d were suitable for the transformation. The optimal cocultivation time was 4 - 5 d. The optimal concentration of kanamycin was 50-75 mg L-1 for suspension culture and 100 mg L-1 for embryogenic callus proliferation and plant regeneration. The optimal concentration of carbencillin was 100 mg L-1. Transgenic plants identified with GUS assays and PCR analyses were obtained.展开更多
In liver cirrhosis, the circulatory hemodynamic alterations of portal hypertension signifi cantly contribute to many of the clinical manifestations of the disease. In the physiopathology of this vascular alteration, m...In liver cirrhosis, the circulatory hemodynamic alterations of portal hypertension signifi cantly contribute to many of the clinical manifestations of the disease. In the physiopathology of this vascular alteration, mesen- teric splanchnic vasodilation plays an essential role by initiating the hemodynamic process. Numerous studies performed in cirrhotic patients and animal models have shown that this splanchnic vasodilation is the result of an important increase in local and systemic vasodilators and the presence of a splanchnic vascular hyporesponsiveness to vasoconstrictors. Among the molecules and factors known to be potentially involved in this arterial vasodilation, nitric oxide seems to have a crucial role in the physiopathology of this vascular alteration. However, none of the wide variety of mediators can be described as solely responsible, since this phenomenon is multifactorial in origin. Moreover, angiogenesis and vascular remodeling processes alsoseem to play a role. Finally, the sympathetic nervous system is thought to be involved in the pathogenesis of the hyperdynamic circulation associated with portal hypertension, although the nature and extent of its role is not completely understood. In this review, we discuss the different mechanisms known to contribute to this complex phenomenon.展开更多
Hybrid Na-ion capacitors(NICs)have received considerable interests owing to their low-cost,high-safety,and rapidly charging energy-storage characteristics.The NICs are composed of a capacitor-type cathode and a batter...Hybrid Na-ion capacitors(NICs)have received considerable interests owing to their low-cost,high-safety,and rapidly charging energy-storage characteristics.The NICs are composed of a capacitor-type cathode and a battery-type anode.The major challenge for NICs is to search for suitable electrode materials to overcome the sluggish diffusion of Na^(+)in the anode.Herein,ultrafine vanadium sulfide is encapsulated in carbon fiber(V_(3)S_(4)@CNF)as a self-supported electrode by electrospinning and in situ sulfurization.The carbon cladding and one-dimensional(ID)nanofiber network-like structure could alleviate the volume expansion of V_(3)S_(4)during Na^(+)de-/intercalation process.Consequently,the V_(3)S_(4)@CNF anode exhibited a pseudocapacitive sodium storage in terms of large Na^(+)-storage capacity(476 mAh·g^(-1)at 0.1A·g^(-1)),high-rate capability(290 mAh·g^(-1)at 20.0 A·g^(-1))and excellent cycling stability(95%capacity retention for1500 cycles at 2.0 A·g^(-1))in Na half-cells.By employing V_(3)S_(4)@CNF as the anode and the activated carbon(AC)cathode,the as-assembled NICs could deliver a high energy density of 110 Wh·kg^(-1)at a power density of200 W·kg^(-1).Even at a high power of 10,000 W·kg^(-1),the specific energy is still up to 42 Wh·kg^(-1).展开更多
文摘电力变压器匝间故障将导致绝缘击穿,甚至造成整个电网事故的发生,为此,应用在线频率响应分析法检测变压器绕组变形。通过安装于变压器套管表面的非侵入式电容传感器（NICS）将测试信号通过高压套管注入变压器绕组从而实现了绕组变形的在线监测。开发了基于脉冲信号注入法的变压器绕组变形在线监测系统。着重阐述了测试信号的选择,在线信号的注入,保护电路的设计。分析了信号源和采样频率对频响特性测试结果的影响。对一台型号为35 k VA/10 k V/400 V的配电变压器进行测试,并与安捷伦频谱网络分析仪4395A的测试结果进行对比发现,在0~5 MHz频率范围内,两条频响曲线的相关系数为0.955 3。结果表明,该系统能在在线状态下准确、快速地获取变压器绕组数10 MHz内的频响特性。监测系统具有较高的灵敏度和重复性,能有效检测变压器绕组变形。
基金supported by the National Natural Science Foundation of China(30170587)the National High Tech R&D Program,China(863 Program,2002AA241031,2001AA241181)the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of Ministry of Education,China.
文摘Genetic transformation of embryogenic suspension cultures of sweetpotato cv. Lizixiang was conducted by using Agrobacterium tumefaciens strain A208SE harboring the binary vectors pROA93 with β-glucronidase(GUS)and neomycin phosphotransferase(NPTⅡ)genes. The results indicated that embryogenic suspension cultures precultured for 1 - 3 d were suitable for the transformation. The optimal cocultivation time was 4 - 5 d. The optimal concentration of kanamycin was 50-75 mg L-1 for suspension culture and 100 mg L-1 for embryogenic callus proliferation and plant regeneration. The optimal concentration of carbencillin was 100 mg L-1. Transgenic plants identified with GUS assays and PCR analyses were obtained.
基金Supported by the Grants from the Ministerio de Educacióny Ciencia, No. SAF2006-0314the Ministerio de Cienciae Innovación, No. SAF2009-08354
文摘In liver cirrhosis, the circulatory hemodynamic alterations of portal hypertension signifi cantly contribute to many of the clinical manifestations of the disease. In the physiopathology of this vascular alteration, mesen- teric splanchnic vasodilation plays an essential role by initiating the hemodynamic process. Numerous studies performed in cirrhotic patients and animal models have shown that this splanchnic vasodilation is the result of an important increase in local and systemic vasodilators and the presence of a splanchnic vascular hyporesponsiveness to vasoconstrictors. Among the molecules and factors known to be potentially involved in this arterial vasodilation, nitric oxide seems to have a crucial role in the physiopathology of this vascular alteration. However, none of the wide variety of mediators can be described as solely responsible, since this phenomenon is multifactorial in origin. Moreover, angiogenesis and vascular remodeling processes alsoseem to play a role. Finally, the sympathetic nervous system is thought to be involved in the pathogenesis of the hyperdynamic circulation associated with portal hypertension, although the nature and extent of its role is not completely understood. In this review, we discuss the different mechanisms known to contribute to this complex phenomenon.
基金financially supported by the National Natural Science Foundation of China(No.22279122)Zhejiang Provincial Natural Science Foundation of China(No.LZ22B030004)the Foundation of State Key Laboratory of Coal Conversion(No.J22-23-909)。
文摘Hybrid Na-ion capacitors(NICs)have received considerable interests owing to their low-cost,high-safety,and rapidly charging energy-storage characteristics.The NICs are composed of a capacitor-type cathode and a battery-type anode.The major challenge for NICs is to search for suitable electrode materials to overcome the sluggish diffusion of Na^(+)in the anode.Herein,ultrafine vanadium sulfide is encapsulated in carbon fiber(V_(3)S_(4)@CNF)as a self-supported electrode by electrospinning and in situ sulfurization.The carbon cladding and one-dimensional(ID)nanofiber network-like structure could alleviate the volume expansion of V_(3)S_(4)during Na^(+)de-/intercalation process.Consequently,the V_(3)S_(4)@CNF anode exhibited a pseudocapacitive sodium storage in terms of large Na^(+)-storage capacity(476 mAh·g^(-1)at 0.1A·g^(-1)),high-rate capability(290 mAh·g^(-1)at 20.0 A·g^(-1))and excellent cycling stability(95%capacity retention for1500 cycles at 2.0 A·g^(-1))in Na half-cells.By employing V_(3)S_(4)@CNF as the anode and the activated carbon(AC)cathode,the as-assembled NICs could deliver a high energy density of 110 Wh·kg^(-1)at a power density of200 W·kg^(-1).Even at a high power of 10,000 W·kg^(-1),the specific energy is still up to 42 Wh·kg^(-1).
