China is an important country in iron and steel industry.Power electronics converters are widely used.For the cold rolling mills of high speed,AC-DC-AC converters should be used.In the paper,the design and the control...China is an important country in iron and steel industry.Power electronics converters are widely used.For the cold rolling mills of high speed,AC-DC-AC converters should be used.In the paper,the design and the control system of the large power three-level AC - DC - AC converter with IGCTs is investigated,and a back-to-back large power three-level AC - DC - AC converter with IGCTs has been got. With a series experiments,the performance of the converter is examined.The experiment result indicates the converter reaches the design requirement and it shows excellent performance.The converter system has been put into use safely.It is estimated that the AC - DC - AC converter system will be used in the drive systems for rolling mills in the near future.展开更多
Ocean waves can directly drive WECs （wave energy converters） to perform two types of motion--reciprocating motion and unidirectional rotary motion. In general, the efficiency of a reciprocating WEC is strongly wave-...Ocean waves can directly drive WECs （wave energy converters） to perform two types of motion--reciprocating motion and unidirectional rotary motion. In general, the efficiency of a reciprocating WEC is strongly wave-frequency dependent, whereas the efficiency of a rotary WEC can be somewhat wave-frequency independent. To date, a huge majority of WEC technologies under development in industry belong to the reciprocating class, and only a few WEC concepts fall in the unidirectional rotary class. In the present work, a wave-driven rotor for unidirectional rotary motion was proposed and characterized. A numerical tool has been developed for characterization of the rotor＇s unidirectional rotary tendency. The tool included a wave model and a drag force model. Simple circular tubes were used as blades in a basic rotor design. This basic design demonstrated strong potential for unidirectional rotary motion at a proper rotor submersion level and under various wave conditions. Two improved designs were yielded from the basic design. In one improved design, the original circular tubes were replaced with cylindrical shells of semicircular cross section as new blades. In another design, the semicircular shells were further modified to become one-way foldable. The two improvements significantly enhanced the rotors＇ unidirectional rotary tendency in waves, which has been verified by numerical simulation. Broad ranges of wave parameters and the submersion level have been numerically explored on the two improved rotor designs in conjunction with dimensional analysis.展开更多
双馈风电场经串补电容并网时,可能引发次同步控制相互作用(subsynchronous control interaction,SSCI),严重威胁系统安全稳定运行。通过在风机控制器中引入陷波器可有效阻断SSCI,然而固定参数陷波器难以适应实际系统中次同步振荡表现出...双馈风电场经串补电容并网时,可能引发次同步控制相互作用(subsynchronous control interaction,SSCI),严重威胁系统安全稳定运行。通过在风机控制器中引入陷波器可有效阻断SSCI,然而固定参数陷波器难以适应实际系统中次同步振荡表现出的频率大范围时变特征。为解决这一问题,该文提出一种基于改进自适应陷波(adaptive notch filter,ANF)的双馈风电场时变次同步振荡抑制策略。首先,分析ANF安装于风机转子侧变流器(rotor-side converter,RSC)不同位置时对次同步振荡分量的阻断效果,确定ANF的最佳安装位置;其次,基于紧缩技术近似投影子空间跟踪算法(projection approximation subspace tracking based on the deflation technique,PASTd)在线获取次同步振荡信息,提出总体控制架构,设计基于量测数据辨识的ANF中心频率更新策略;最终,在考虑风速、风机台数、无功出力、电网拓扑变化等多种影响因素的情况下,验证控制策略对频率时变次同步振荡的抑制效果。与现有方法相比,所提控制策略不依赖于系统的准确数学模型,且具备较强的鲁棒性和适应性。展开更多
Hepatic fibrosis is considered a common response to many chronic hepatic injuries. It is a multifunctional process that involves several cell types, cytokines, chemokines and growth factors leading to a disruption of ...Hepatic fibrosis is considered a common response to many chronic hepatic injuries. It is a multifunctional process that involves several cell types, cytokines, chemokines and growth factors leading to a disruption of homeostatic mechanisms that maintain the liver ecosystem. In spite of many studies regarding the development of fibrosis, the understanding of the pathogenesis remains obscure. The hepatic tissue remodeling process is highly complex, resulting from the balance between collagen degradation and synthesis. Among the many mediators that take part in this process, the components of the Renin angiotensin system （RAS） have progressively assumed an important role. Angiotensin （Ang） II acts as a profibrotic mediator and Ang-（1-7）, the newly recognized RAS component, appears to exert a counter-regulatory role in liver tissue. We briefly review the liver fibrosis process and current aspects of the RAS. This review also aims to discuss some experimental evidence regarding the participation of RAS mediators in the pathogenesis of liver fibrosis, focusing on the putative role of the ACE2-Ang-（1-7）- Mas receptor axis.展开更多
AIM： To measure circulating angiotensins at different stages of human cirrhosis and to further evaluate a possible relationship between renin angiotensin system （RAS） components and hemodynamic changes. METHODS： P...AIM： To measure circulating angiotensins at different stages of human cirrhosis and to further evaluate a possible relationship between renin angiotensin system （RAS） components and hemodynamic changes. METHODS： Patients were allocated into 4 groups： mild-to-moderate liver disease （MLD）, advanced liver disease （ALD）, patients undergoing liver transplantation, and healthy controls. Blood was collected to determine plasma renin activity （PRA）, angiotensin （Ang） Ⅰ, Ang Ⅱ, and Ang-（1-7） levels using radioimmunoassays. During liver transplantation, hemodynamic parameters were determined and blood was simultaneously obtained from the portal vein and radial artery in order to measure RAS components. RESULTS： PRA and angiotensins were elevated in ALD when compared to MLD and controls （P 〈 0.05）. In contrast, Ang Ⅱ was significantly reduced in MLD. Ang-（1-7）/Ang Ⅱ ratios were increased in MLD when compared to controls and ALD. During transplantation, Ang Ⅱ levels were lower and Ang-（1-7）/Ang Ⅱ ratios were higher in the splanchnic circulation than in the peripheral circulation （0.52 ± 0.08 vs 0.38 ±0.04, P 〈 0.02）, whereas the peripheral circulating Ang Ⅱ/Ang Ⅰ ratio was elevated in comparison to splanchnic levels （0.18 ±0.02 vs 0.13 ±0.02, P 〈 0.04）. Ang-（1-7）/ Ang Ⅱ ratios positively correlated with cardiac output （r = 0.66） and negatively correlated with systemic vascular resistance （r = -0.70）. CONCLUSION： Our findings suggest that the relationship between Ang-（1-7） and Ang Ⅱ may play a role in the hemodynamic changes of human cirrhosis.展开更多
The renin angiotensin system(RAS) is classically conceived as a circulating hormonal system involved in blood pressure control and hydroelectrolyte balance. The discovery that RAS components are locally expressed in a...The renin angiotensin system(RAS) is classically conceived as a circulating hormonal system involved in blood pressure control and hydroelectrolyte balance. The discovery that RAS components are locally expressed in a wide range of organs and tissues,including the liver,pointed to a role for this system in the pathogenesis of several conditions including hepatic fibrosis and cirrhosis. It has been widely reported that the classical RAS axis composed by the angiotensin converting enzyme(ACE)-angiotensin(Ang) Ⅱ-Ang type 1(AT1) receptor mediates pro-inflammatory,pro-thrombotic,and pro-fibrotic processes. On the other hand,the alternative axis comprising ACE2-Ang-(1-7)-Mas receptor seems to play a protective role by frequently opposing Ang Ⅱ action. Chronic hepatitis B(CHB) is one of the leading causes of liver fibrosis,accounting for the death of nearly one million people worldwide. Liver fibrosis is a key factor to determine therapeutic interventions for patients with CHB. However,the establishment of non-invasive and accurate methods to detect reversible stages of liver fibrosis is still a challenge. In an elegant study published in the 36 th issue of the World Journal of Gastroenterology,Noguchi et al showed the predictive value of serum ACE levels in detecting not only advanced stages of liver fibrosis but also initial and intermediate fibrotic stages. The serum levels of ACE might represent an accurate,non-invasive,widely available,and easy method to evaluate fibrosis related to CHB. Moreover,therapies involving the inhibition of the classical RAS axis components might be promising in the control of CHB-related liver fibrosis.展开更多
In this paper, the design and verification process of an automobile-engine-fan control system on chip （SoC） are introduced. The SoC system, SHU-MV08, reuses four new intellectual property （IP） cores and the design...In this paper, the design and verification process of an automobile-engine-fan control system on chip （SoC） are introduced. The SoC system, SHU-MV08, reuses four new intellectual property （IP） cores and the design flow is accomplished with 0.35 btm chartered CMOS technology. Some special functions of IP cores, the detailed integration scheme of four IP cores, and the verification method of the entire SoC are presented. To settle the verification problems brought by analog IP cores, NanoSim based chip-level mixed-signal verification method is introduced. The verification time is greatly reduced and the first tape-out achieves success which proves the validity of our design.展开更多
Abstract: A micro - power consumption non - contact temperature measuring instrument for big rotor is introduced. As it solves very well the signal coupling under high speed rotation and power supply problem for probe...Abstract: A micro - power consumption non - contact temperature measuring instrument for big rotor is introduced. As it solves very well the signal coupling under high speed rotation and power supply problem for probe, the instrument can realize persistent on - line temperature measurement for big rotor drived by the ordinary light transmitted by optical fiber under the room light.展开更多
The renin-angiotensin system(RAS) regulates blood pressure(BP) homeostasis, systemic fluid volume and electrolyte balance. The RAS cascade includes over twenty peptidases, close to twenty angiotensin peptides and at l...The renin-angiotensin system(RAS) regulates blood pressure(BP) homeostasis, systemic fluid volume and electrolyte balance. The RAS cascade includes over twenty peptidases, close to twenty angiotensin peptides and at least six receptors. Out of these, angiotensin Ⅱ, angiotensin converting enzyme 1 and angiotensin Ⅱ type 1 receptor(AngⅡ-ACE1-AT1R) together with angiotensin(1-7), angiotensin converting enzyme 2 and Mas receptor(Ang(1-7)-ACE2-Mas R) are regarded as the main components of RAS. In addition to circulating RAS, local RA-system exists in various organs. Local RA-systems are regarded as tissue-specific regulatory system accounting for local effects and long term changes in different organs. Many of the central components such as the two main axes of RAS: AngⅡ-ACE1-AT1 R and Ang(1-7)-ACE2-Mas R, have been identified in the human eye. Furthermore, it has been shown that systemic antihypertensive RAS- inhibiting medications lower intraocular pressure(IOP). These findings suggest the crucial role of RAS not only in the regulation of BP but also in the regulation of IOP, and RAS potentially plays a role in the development of glaucoma and antiglaucomatous drugs.展开更多
文摘China is an important country in iron and steel industry.Power electronics converters are widely used.For the cold rolling mills of high speed,AC-DC-AC converters should be used.In the paper,the design and the control system of the large power three-level AC - DC - AC converter with IGCTs is investigated,and a back-to-back large power three-level AC - DC - AC converter with IGCTs has been got. With a series experiments,the performance of the converter is examined.The experiment result indicates the converter reaches the design requirement and it shows excellent performance.The converter system has been put into use safely.It is estimated that the AC - DC - AC converter system will be used in the drive systems for rolling mills in the near future.
文摘Ocean waves can directly drive WECs （wave energy converters） to perform two types of motion--reciprocating motion and unidirectional rotary motion. In general, the efficiency of a reciprocating WEC is strongly wave-frequency dependent, whereas the efficiency of a rotary WEC can be somewhat wave-frequency independent. To date, a huge majority of WEC technologies under development in industry belong to the reciprocating class, and only a few WEC concepts fall in the unidirectional rotary class. In the present work, a wave-driven rotor for unidirectional rotary motion was proposed and characterized. A numerical tool has been developed for characterization of the rotor＇s unidirectional rotary tendency. The tool included a wave model and a drag force model. Simple circular tubes were used as blades in a basic rotor design. This basic design demonstrated strong potential for unidirectional rotary motion at a proper rotor submersion level and under various wave conditions. Two improved designs were yielded from the basic design. In one improved design, the original circular tubes were replaced with cylindrical shells of semicircular cross section as new blades. In another design, the semicircular shells were further modified to become one-way foldable. The two improvements significantly enhanced the rotors＇ unidirectional rotary tendency in waves, which has been verified by numerical simulation. Broad ranges of wave parameters and the submersion level have been numerically explored on the two improved rotor designs in conjunction with dimensional analysis.
文摘双馈风电场经串补电容并网时,可能引发次同步控制相互作用(subsynchronous control interaction,SSCI),严重威胁系统安全稳定运行。通过在风机控制器中引入陷波器可有效阻断SSCI,然而固定参数陷波器难以适应实际系统中次同步振荡表现出的频率大范围时变特征。为解决这一问题,该文提出一种基于改进自适应陷波(adaptive notch filter,ANF)的双馈风电场时变次同步振荡抑制策略。首先,分析ANF安装于风机转子侧变流器(rotor-side converter,RSC)不同位置时对次同步振荡分量的阻断效果,确定ANF的最佳安装位置;其次,基于紧缩技术近似投影子空间跟踪算法(projection approximation subspace tracking based on the deflation technique,PASTd)在线获取次同步振荡信息,提出总体控制架构,设计基于量测数据辨识的ANF中心频率更新策略;最终,在考虑风速、风机台数、无功出力、电网拓扑变化等多种影响因素的情况下,验证控制策略对频率时变次同步振荡的抑制效果。与现有方法相比,所提控制策略不依赖于系统的准确数学模型,且具备较强的鲁棒性和适应性。
文摘Hepatic fibrosis is considered a common response to many chronic hepatic injuries. It is a multifunctional process that involves several cell types, cytokines, chemokines and growth factors leading to a disruption of homeostatic mechanisms that maintain the liver ecosystem. In spite of many studies regarding the development of fibrosis, the understanding of the pathogenesis remains obscure. The hepatic tissue remodeling process is highly complex, resulting from the balance between collagen degradation and synthesis. Among the many mediators that take part in this process, the components of the Renin angiotensin system （RAS） have progressively assumed an important role. Angiotensin （Ang） II acts as a profibrotic mediator and Ang-（1-7）, the newly recognized RAS component, appears to exert a counter-regulatory role in liver tissue. We briefly review the liver fibrosis process and current aspects of the RAS. This review also aims to discuss some experimental evidence regarding the participation of RAS mediators in the pathogenesis of liver fibrosis, focusing on the putative role of the ACE2-Ang-（1-7）- Mas receptor axis.
基金Supported by Fundacode Amparo à Pesquisa do Estado de Minas Gerais, Conselho Nacional de Desenvolvimento Científico e Tecnológico, FAPEMIG/CNPQ-PRONEX (Grupos de Excelência),Ministério de Ciência e Tecnologia/CNPq/ FAPEMIG-INCT-Nano-Biofar
文摘AIM： To measure circulating angiotensins at different stages of human cirrhosis and to further evaluate a possible relationship between renin angiotensin system （RAS） components and hemodynamic changes. METHODS： Patients were allocated into 4 groups： mild-to-moderate liver disease （MLD）, advanced liver disease （ALD）, patients undergoing liver transplantation, and healthy controls. Blood was collected to determine plasma renin activity （PRA）, angiotensin （Ang） Ⅰ, Ang Ⅱ, and Ang-（1-7） levels using radioimmunoassays. During liver transplantation, hemodynamic parameters were determined and blood was simultaneously obtained from the portal vein and radial artery in order to measure RAS components. RESULTS： PRA and angiotensins were elevated in ALD when compared to MLD and controls （P 〈 0.05）. In contrast, Ang Ⅱ was significantly reduced in MLD. Ang-（1-7）/Ang Ⅱ ratios were increased in MLD when compared to controls and ALD. During transplantation, Ang Ⅱ levels were lower and Ang-（1-7）/Ang Ⅱ ratios were higher in the splanchnic circulation than in the peripheral circulation （0.52 ± 0.08 vs 0.38 ±0.04, P 〈 0.02）, whereas the peripheral circulating Ang Ⅱ/Ang Ⅰ ratio was elevated in comparison to splanchnic levels （0.18 ±0.02 vs 0.13 ±0.02, P 〈 0.04）. Ang-（1-7）/ Ang Ⅱ ratios positively correlated with cardiac output （r = 0.66） and negatively correlated with systemic vascular resistance （r = -0.70）. CONCLUSION： Our findings suggest that the relationship between Ang-（1-7） and Ang Ⅱ may play a role in the hemodynamic changes of human cirrhosis.
文摘为提高风力双馈电机(Doubly-Fed Induction Generator,DFIG)发出的电能质量,文章针对转子侧变换器提出了一种基于空间矢量调制(Space Vector Modulation,SVM)的预测(Predictive,P)直接功率控制(Director Power Control,DPC)的SVM P-DPC策略。该控制策略通过预测模型能够预测出消除下一个采样周期中功率偏差所需要的转子励磁电压,并结合SVM技术,实现对DFIG输出功率的控制。利用Simulink仿真平台,搭建该控制系统的仿真模型,并在2.2 k W的DFIG实验平台上进行实验验证。仿真及实验结果表明,该控制策略动态响应快,鲁棒性强,双馈电机发出的功率稳定。
基金Supported by CNPq,No.460334/2014-0FAPEMIG,No.CDS-PPM-00555-15(to Simoes e Silva AC)2016 NARSAD Young Investigator Grant Awardee from the Brain and Behavior Research Foundation,No.25414(to Miranda AS)
文摘The renin angiotensin system(RAS) is classically conceived as a circulating hormonal system involved in blood pressure control and hydroelectrolyte balance. The discovery that RAS components are locally expressed in a wide range of organs and tissues,including the liver,pointed to a role for this system in the pathogenesis of several conditions including hepatic fibrosis and cirrhosis. It has been widely reported that the classical RAS axis composed by the angiotensin converting enzyme(ACE)-angiotensin(Ang) Ⅱ-Ang type 1(AT1) receptor mediates pro-inflammatory,pro-thrombotic,and pro-fibrotic processes. On the other hand,the alternative axis comprising ACE2-Ang-(1-7)-Mas receptor seems to play a protective role by frequently opposing Ang Ⅱ action. Chronic hepatitis B(CHB) is one of the leading causes of liver fibrosis,accounting for the death of nearly one million people worldwide. Liver fibrosis is a key factor to determine therapeutic interventions for patients with CHB. However,the establishment of non-invasive and accurate methods to detect reversible stages of liver fibrosis is still a challenge. In an elegant study published in the 36 th issue of the World Journal of Gastroenterology,Noguchi et al showed the predictive value of serum ACE levels in detecting not only advanced stages of liver fibrosis but also initial and intermediate fibrotic stages. The serum levels of ACE might represent an accurate,non-invasive,widely available,and easy method to evaluate fibrosis related to CHB. Moreover,therapies involving the inhibition of the classical RAS axis components might be promising in the control of CHB-related liver fibrosis.
基金Project supported by the IC Special Foundation of Shanghai Municipal Commission of Science and Technology (Grant No.09706201300)the Shanghai Municipal Commission of Economic and Information (Grant No.090344)the Shanghai High-Tech Industrialization of New Energy Vehicles (Grant No.09625029),and the Graduate Innovation Foundation of Shanghai University
文摘In this paper, the design and verification process of an automobile-engine-fan control system on chip （SoC） are introduced. The SoC system, SHU-MV08, reuses four new intellectual property （IP） cores and the design flow is accomplished with 0.35 btm chartered CMOS technology. Some special functions of IP cores, the detailed integration scheme of four IP cores, and the verification method of the entire SoC are presented. To settle the verification problems brought by analog IP cores, NanoSim based chip-level mixed-signal verification method is introduced. The verification time is greatly reduced and the first tape-out achieves success which proves the validity of our design.
文摘Abstract: A micro - power consumption non - contact temperature measuring instrument for big rotor is introduced. As it solves very well the signal coupling under high speed rotation and power supply problem for probe, the instrument can realize persistent on - line temperature measurement for big rotor drived by the ordinary light transmitted by optical fiber under the room light.
基金Supported by Päivikki and Sakari Sohlberg Foundationthe Eye Foundation+2 种基金the Glaucoma Research Foundation Luxthe Competitive Research Funding of Tampere University Hospital,No.9S072and the Foundation for Clinical Chemistry Research.
文摘The renin-angiotensin system(RAS) regulates blood pressure(BP) homeostasis, systemic fluid volume and electrolyte balance. The RAS cascade includes over twenty peptidases, close to twenty angiotensin peptides and at least six receptors. Out of these, angiotensin Ⅱ, angiotensin converting enzyme 1 and angiotensin Ⅱ type 1 receptor(AngⅡ-ACE1-AT1R) together with angiotensin(1-7), angiotensin converting enzyme 2 and Mas receptor(Ang(1-7)-ACE2-Mas R) are regarded as the main components of RAS. In addition to circulating RAS, local RA-system exists in various organs. Local RA-systems are regarded as tissue-specific regulatory system accounting for local effects and long term changes in different organs. Many of the central components such as the two main axes of RAS: AngⅡ-ACE1-AT1 R and Ang(1-7)-ACE2-Mas R, have been identified in the human eye. Furthermore, it has been shown that systemic antihypertensive RAS- inhibiting medications lower intraocular pressure(IOP). These findings suggest the crucial role of RAS not only in the regulation of BP but also in the regulation of IOP, and RAS potentially plays a role in the development of glaucoma and antiglaucomatous drugs.
