Functional dyspepsia is a symptom complex characterised by upper abdominal discomfort or pain, early satiety, motor abnormalities, abdominal bloating and nausea in the absence of organic disease. The central nervous s...Functional dyspepsia is a symptom complex characterised by upper abdominal discomfort or pain, early satiety, motor abnormalities, abdominal bloating and nausea in the absence of organic disease. The central nervous system plays an important role in the conducting and processing of visceral signals. Alterations in brain processing of pain, perception and affective responses may be key factors in the pathogenesis of functional dyspepsia. Central serotonergic and noradrenergic receptor systems are involved in the processing of motor, sensory and secretory activities of the gastrointestinal tract. Visceral hypersensitivity is currently regarded as the mechanism responsible for both motor alterations and abdominal pain in functional dyspepsia. Some studies suggest that there are alterations in central serotonergic and noradrenergic systems which may partially explain some of the symptoms of functional dyspepsia. Alterations in the autonomic nervous system may be implicated in the motor abnormalities and increases in visceral sensitivity in these patients. Noradrenaline is the main neurotransmitter in the sympathetic nervous system and again alterations in the functioning of this system may lead to changes in motor function. Functional dyspepsia causes considerable burden on the patient and society. The pathophysiology of functional dyspepsia is not fully understood but alterations in central processing by the serotonergic and noradrenergic systems may provide plausible explanations for at least some of the symptoms and offer possible treatment targets for the future.展开更多
The power grid with large proportion of hydropower may engage the ultra-low frequency oscillation (ULFO),which threatening the operation of system.To the NY Power Grid system,whose dimension is over thousands,this pap...The power grid with large proportion of hydropower may engage the ultra-low frequency oscillation (ULFO),which threatening the operation of system.To the NY Power Grid system,whose dimension is over thousands,this paper reveals the cause of ULFO with the phase portrait method,i.e.,lies in the saturation of the different limits of the governor system of the generators,in other words,the occurrence of limit cycle is due to the non-smooth bifurcation.And furthermore,it proposes two methods to suppress ULFO with the philosophy of destroying the condition of non-smooth bifurcation.In detail,first,the phenomenon of ULFO in NY Power Grid,the damping characteristics and the limits in the governor system of the hydropower units are presented.Second,based on the non-smooth bifurcation theory,the mathematical basis of the oscillation in the non-smooth system caused by the saturation of limits is introduced.And then,the non-oscillation and oscillation dynamic of the system corresponding to without/with limits in the governor system are analyzed.Furthermore,it discusses the influence of the saturation of single limit on the characteristics of ULFO with the phase portraits.Moreover,the phase portraits of the ULFO under different faults is analyzed,and it shows that the limiting saturation occurs with a large enough disturbance.Thus,the ULFO is resulting from the negative damping of generation and the saturation of multiple limits under a large enough disturbance.In addition,according to the above mechanism,two strategies to suppress the ULFO,i.e.,the governor parameters tuning and the fault strength relief are designed.The simulation shows the effectiveness of proposed strategies.展开更多
为满足医学系统芯片(SOC)的低成本、低功耗、微型化的需求,定制了一款兼容AHB总线接口的NorFlash控制器IP.该设计针对常规Flash控制器功能繁杂,读写数据需长时间等待等缺点,采用了硬件解锁、简化块擦除模块和增加写操作数据寄存器等优...为满足医学系统芯片(SOC)的低成本、低功耗、微型化的需求,定制了一款兼容AHB总线接口的NorFlash控制器IP.该设计针对常规Flash控制器功能繁杂,读写数据需长时间等待等缺点,采用了硬件解锁、简化块擦除模块和增加写操作数据寄存器等优化设计方法.该设计最后进行了FPGA原型验证并进行了流片,验证测试结果表明,该IP功能正确,总线的利用率得到了提高.在系统时钟10MHz下,选用S29L V008J Nor Flash芯片,按连续存储16个32位数据计算,本设计比常规设计减少总线占用时间165μs,设计达到了预期结果.展开更多
基金the Health Research Board(Ireland),Science Foundation Ireland through the Alimentary Pharmabiotic Centre and the Wellcome Trust.
文摘Functional dyspepsia is a symptom complex characterised by upper abdominal discomfort or pain, early satiety, motor abnormalities, abdominal bloating and nausea in the absence of organic disease. The central nervous system plays an important role in the conducting and processing of visceral signals. Alterations in brain processing of pain, perception and affective responses may be key factors in the pathogenesis of functional dyspepsia. Central serotonergic and noradrenergic receptor systems are involved in the processing of motor, sensory and secretory activities of the gastrointestinal tract. Visceral hypersensitivity is currently regarded as the mechanism responsible for both motor alterations and abdominal pain in functional dyspepsia. Some studies suggest that there are alterations in central serotonergic and noradrenergic systems which may partially explain some of the symptoms of functional dyspepsia. Alterations in the autonomic nervous system may be implicated in the motor abnormalities and increases in visceral sensitivity in these patients. Noradrenaline is the main neurotransmitter in the sympathetic nervous system and again alterations in the functioning of this system may lead to changes in motor function. Functional dyspepsia causes considerable burden on the patient and society. The pathophysiology of functional dyspepsia is not fully understood but alterations in central processing by the serotonergic and noradrenergic systems may provide plausible explanations for at least some of the symptoms and offer possible treatment targets for the future.
基金National Natural Science Foundation of China (Nos. 51477050, 50707035) and 111 plan (No. B08013).
文摘The power grid with large proportion of hydropower may engage the ultra-low frequency oscillation (ULFO),which threatening the operation of system.To the NY Power Grid system,whose dimension is over thousands,this paper reveals the cause of ULFO with the phase portrait method,i.e.,lies in the saturation of the different limits of the governor system of the generators,in other words,the occurrence of limit cycle is due to the non-smooth bifurcation.And furthermore,it proposes two methods to suppress ULFO with the philosophy of destroying the condition of non-smooth bifurcation.In detail,first,the phenomenon of ULFO in NY Power Grid,the damping characteristics and the limits in the governor system of the hydropower units are presented.Second,based on the non-smooth bifurcation theory,the mathematical basis of the oscillation in the non-smooth system caused by the saturation of limits is introduced.And then,the non-oscillation and oscillation dynamic of the system corresponding to without/with limits in the governor system are analyzed.Furthermore,it discusses the influence of the saturation of single limit on the characteristics of ULFO with the phase portraits.Moreover,the phase portraits of the ULFO under different faults is analyzed,and it shows that the limiting saturation occurs with a large enough disturbance.Thus,the ULFO is resulting from the negative damping of generation and the saturation of multiple limits under a large enough disturbance.In addition,according to the above mechanism,two strategies to suppress the ULFO,i.e.,the governor parameters tuning and the fault strength relief are designed.The simulation shows the effectiveness of proposed strategies.
文摘为满足医学系统芯片(SOC)的低成本、低功耗、微型化的需求,定制了一款兼容AHB总线接口的NorFlash控制器IP.该设计针对常规Flash控制器功能繁杂,读写数据需长时间等待等缺点,采用了硬件解锁、简化块擦除模块和增加写操作数据寄存器等优化设计方法.该设计最后进行了FPGA原型验证并进行了流片,验证测试结果表明,该IP功能正确,总线的利用率得到了提高.在系统时钟10MHz下,选用S29L V008J Nor Flash芯片,按连续存储16个32位数据计算,本设计比常规设计减少总线占用时间165μs,设计达到了预期结果.
