为降低中点箝位型(neutral point clamped,NPC)三电平整流器的电流谐波,在dq同步旋转坐标系下推导出带中点电压耦合项的NPC三电平整流器数学模型,并分析中点电压对电流控制的影响。对模型中的中点电压耦合项和交流侧等效电阻会增大电流...为降低中点箝位型(neutral point clamped,NPC)三电平整流器的电流谐波,在dq同步旋转坐标系下推导出带中点电压耦合项的NPC三电平整流器数学模型,并分析中点电压对电流控制的影响。对模型中的中点电压耦合项和交流侧等效电阻会增大电流谐波及无法通过常规方法进行准确估计的问题,设计一种混合参数自适应的迭代学习控制方法,以进行解耦控制并消除不确定参数的影响。通过构造Lyapunov函数和理论推导验证控制方法的稳定性。在整流器硬件平台上进行试验验证,结果表明,所设计的控制方法可有效降低电流谐波。展开更多
In this paper, the forced odd order neutral differential equations of the form are considered d n d t n[x(t)-R(t)x(t-τ)]+P(t)x(t-σ)=f(t),t≥t 0.A sufficient condition for the oscillation of all solutions is...In this paper, the forced odd order neutral differential equations of the form are considered d n d t n[x(t)-R(t)x(t-τ)]+P(t)x(t-σ)=f(t),t≥t 0.A sufficient condition for the oscillation of all solutions is obtained.展开更多
In this paper the perturbed neutral differential equation with positive and negative coefficientsddt[x(t)-C(t)x(t-r)]+P(t)x(t-τ)-Q(t)x(t-σ)=f(t,x(t)), t≥t 0is considered. Sufficient conditions for the zero soluti...In this paper the perturbed neutral differential equation with positive and negative coefficientsddt[x(t)-C(t)x(t-r)]+P(t)x(t-τ)-Q(t)x(t-σ)=f(t,x(t)), t≥t 0is considered. Sufficient conditions for the zero solution of this equation to be uniformly stable as well as asymptotically stable are obtained.展开更多
In this paper, we obtained some sufficient conditions for the oscillation of all solutions of the second order neutral differential equation of the form where , and . Examples are provided to illustrate the main results.
Neutralizing antibodies are considered to be an important protective parameter used in HIV-1 vaccine evaluation. However, the exact role that neutralizing antibodies plays in controlling the disease progression of HIV...Neutralizing antibodies are considered to be an important protective parameter used in HIV-1 vaccine evaluation. However, the exact role that neutralizing antibodies plays in controlling the disease progression of HIV-1 infected peoples is still undetermined. In this paper, we compared the protective function of the neutralizing antibody response in the plasma from LTNP and TP against clade B and clade C pseudoviruses. No difference in the neutralizing activities between the plasma from LTNP and TP was found, which was consistent with the most recent reports. In addition, no correlations between the titer or breadth and CD4+ or viral load in HIV-1 infected individuals were found. The protective roles played by neutralizing antibodies in controlling disease progression of HIV-1 infected people need to be considered in a new viewpoint.展开更多
The aim of this paper is to study the asymptotic behavior of the oscillatory solutions of forced nonlinear neutral equations of the form[x(t)-∑mi=1p i(t)x(t-τ i)]′+∑nj=1q j(t)f(x(t-σ j))=r(t),t≥t 0,where...The aim of this paper is to study the asymptotic behavior of the oscillatory solutions of forced nonlinear neutral equations of the form[x(t)-∑mi=1p i(t)x(t-τ i)]′+∑nj=1q j(t)f(x(t-σ j))=r(t),t≥t 0,where p i,q j,r∈C([t 0,∞),R),τ i,σ j≥0,i=1,2,…,m,j=1,2,…,n,f∈C(R,R),xf(x)>0 for x≠0. The results obtained here extend and improve some of the results of Ladas and Sficas [3] and J.R.Yan [5].展开更多
文摘为降低中点箝位型(neutral point clamped,NPC)三电平整流器的电流谐波,在dq同步旋转坐标系下推导出带中点电压耦合项的NPC三电平整流器数学模型,并分析中点电压对电流控制的影响。对模型中的中点电压耦合项和交流侧等效电阻会增大电流谐波及无法通过常规方法进行准确估计的问题,设计一种混合参数自适应的迭代学习控制方法,以进行解耦控制并消除不确定参数的影响。通过构造Lyapunov函数和理论推导验证控制方法的稳定性。在整流器硬件平台上进行试验验证,结果表明,所设计的控制方法可有效降低电流谐波。
文摘In this paper, the forced odd order neutral differential equations of the form are considered d n d t n[x(t)-R(t)x(t-τ)]+P(t)x(t-σ)=f(t),t≥t 0.A sufficient condition for the oscillation of all solutions is obtained.
文摘In this paper the perturbed neutral differential equation with positive and negative coefficientsddt[x(t)-C(t)x(t-r)]+P(t)x(t-τ)-Q(t)x(t-σ)=f(t,x(t)), t≥t 0is considered. Sufficient conditions for the zero solution of this equation to be uniformly stable as well as asymptotically stable are obtained.
文摘In this paper, we obtained some sufficient conditions for the oscillation of all solutions of the second order neutral differential equation of the form where , and . Examples are provided to illustrate the main results.
基金supported in part by the National Key S&T Special Projects on Major Infectious Diseases (Grant No. 2008ZX10001-002, 2008ZX10001-012)the National Natural Science Foundation of China (No. 30700706)
文摘Neutralizing antibodies are considered to be an important protective parameter used in HIV-1 vaccine evaluation. However, the exact role that neutralizing antibodies plays in controlling the disease progression of HIV-1 infected peoples is still undetermined. In this paper, we compared the protective function of the neutralizing antibody response in the plasma from LTNP and TP against clade B and clade C pseudoviruses. No difference in the neutralizing activities between the plasma from LTNP and TP was found, which was consistent with the most recent reports. In addition, no correlations between the titer or breadth and CD4+ or viral load in HIV-1 infected individuals were found. The protective roles played by neutralizing antibodies in controlling disease progression of HIV-1 infected people need to be considered in a new viewpoint.
文摘The aim of this paper is to study the asymptotic behavior of the oscillatory solutions of forced nonlinear neutral equations of the form[x(t)-∑mi=1p i(t)x(t-τ i)]′+∑nj=1q j(t)f(x(t-σ j))=r(t),t≥t 0,where p i,q j,r∈C([t 0,∞),R),τ i,σ j≥0,i=1,2,…,m,j=1,2,…,n,f∈C(R,R),xf(x)>0 for x≠0. The results obtained here extend and improve some of the results of Ladas and Sficas [3] and J.R.Yan [5].
