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
We present a single-mode laser on a p-In P substrate suitable for bonding on silicon-on-insulator（SOI）wafer. The laser can realize single mode lasing with etching perturbing slots by standard photolithography and an...We present a single-mode laser on a p-In P substrate suitable for bonding on silicon-on-insulator（SOI）wafer. The laser can realize single mode lasing with etching perturbing slots by standard photolithography and an inductively coupled-plasma（ICP） etching technique without any regrowth steps. The parameters were designed using the simulation tool ＂cavity modeling framework＂（CAMFR）. The single mode of 1539 nm wavelength at the threshold current of 130 mA with the maximum output power of 3.9 mW was obtained at 10℃ in continuouswave operation. The simple technology, low cost and the single-mode characteristics make the broad area slotted single-mode FP laser a promising light source on the silicon-based optical interconnection applications.展开更多
Based on an Ensemble Prediction System with the BGM method on the regional numerical prediction model AREM, Static State Perturbation （SSP, including Initial Random Perturbation and Perturbation Restriction） and Dyn...Based on an Ensemble Prediction System with the BGM method on the regional numerical prediction model AREM, Static State Perturbation （SSP, including Initial Random Perturbation and Perturbation Restriction） and Dynamic State Perturbation （DSP） are designed. The impacts of both perturbations on precipitation prediction are studied by analyzing a slrong precipitation process oc- curring during July 20-21, 2008. The results show that both SSP and DSP play a positive role in prediction of mesoscale precipita- tion, such as lowering the （missing） rate of precipitation prediction. SSP is mainly helpful for the 24-hour prediction, while DSP can improve both 24-hour and 48-hour prediction. DSP is better than the two SSPs in the hit rate of regional precipitation prediction. However, the former also has a little higher false alarm rate than the latter. DSP enlarges in some extent the dispersion of EPS, which is good for EPS.展开更多
In this paper, we use perturbing families of gernerlized Lyapunov functions to discuss ' the relative stability of ordinary differential systems in terms of two measures and gain some criteria for this stability o...In this paper, we use perturbing families of gernerlized Lyapunov functions to discuss ' the relative stability of ordinary differential systems in terms of two measures and gain some criteria for this stability of asymptotic.'展开更多
A new method, BDA perturbing, is used in ensemble forecasting of typhoon track. This method is based on the Bogus Data Assimilation scheme. It perturbs the initial position and intensity of typhoons and gets; a series...A new method, BDA perturbing, is used in ensemble forecasting of typhoon track. This method is based on the Bogus Data Assimilation scheme. It perturbs the initial position and intensity of typhoons and gets; a series of bogus vortex. Then each bogus vortex is used in data assimilation to obtain initial conditions. Ensemble forecast members are constructed by conducting simulation with these initial conditions. Some cases of typhoon are chosen to test the validity of this new method and the results show that： using the BDA perturbing method to perturb initial position and intensity of typhoon for track tbrecast can improve accuracy, compared with the direct use of the BDA assimilation scheme. And it is concluded that a perturbing amplitude of intensity of 5 hPa is probably more appropriate than 10 hPa if the BDA perturbing method is used in combination with initial position perturbation.展开更多
为提高系统的能量利用率和运行可靠性,提出了一种用于电流源逆变器(current source inverter,CSI)光伏并网系统最大功率跟踪(maximum power point tracking,MPPT)方法。该方法通过扰动电阻代替传统扰动观察法中扰动电流实现CSI光伏系统...为提高系统的能量利用率和运行可靠性,提出了一种用于电流源逆变器(current source inverter,CSI)光伏并网系统最大功率跟踪(maximum power point tracking,MPPT)方法。该方法通过扰动电阻代替传统扰动观察法中扰动电流实现CSI光伏系统的MPPT,有效避免了传统扰动电流MPPT法存在的最大功率点右侧电流易于失控和功率瞬时跌落的问题。实验结果表明,该扰动电阻MPPT(perturbing resistance MPPT,PR-MPPT)法应用于CSI光伏并网系统,能够有效实现系统的最大功率运行。展开更多
在建立区域AREM模式增长模繁殖(Breeding of Growing Modes,BGM)集合预报系统的基础上,设计了静态扰动(初始随机扰动、扰动限定)和动态扰动方法,利用2008年7月20日强降水个例,分析了不同类型扰动对强降水预报的影响。结果表明,静态和动...在建立区域AREM模式增长模繁殖(Breeding of Growing Modes,BGM)集合预报系统的基础上,设计了静态扰动(初始随机扰动、扰动限定)和动态扰动方法,利用2008年7月20日强降水个例,分析了不同类型扰动对强降水预报的影响。结果表明,静态和动态扰动都对中尺度暴雨预报具有积极的作用,扰动都不同程度地减少了漏报率。两种静态扰动对预报的改善集中在24 h降水预报,动态扰动则对24 h和48 h降水预报都有不同程度的改进。两种静态扰动的区域性降水空报率、漏报率相同,而动态扰动的区域性强降水漏报率低于静态扰动,同时,区域性强降水空报率也较静态扰动略高。动态扰动一定程度地增大了集合预报的离散度。展开更多
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We present a single-mode laser on a p-In P substrate suitable for bonding on silicon-on-insulator（SOI）wafer. The laser can realize single mode lasing with etching perturbing slots by standard photolithography and an inductively coupled-plasma（ICP） etching technique without any regrowth steps. The parameters were designed using the simulation tool ＂cavity modeling framework＂（CAMFR）. The single mode of 1539 nm wavelength at the threshold current of 130 mA with the maximum output power of 3.9 mW was obtained at 10℃ in continuouswave operation. The simple technology, low cost and the single-mode characteristics make the broad area slotted single-mode FP laser a promising light source on the silicon-based optical interconnection applications.
基金supported by the Special Fund for Meteorology Scientific Research in the Public Interest in 2007(GYHY(QX)2007-6-12)
文摘Based on an Ensemble Prediction System with the BGM method on the regional numerical prediction model AREM, Static State Perturbation （SSP, including Initial Random Perturbation and Perturbation Restriction） and Dynamic State Perturbation （DSP） are designed. The impacts of both perturbations on precipitation prediction are studied by analyzing a slrong precipitation process oc- curring during July 20-21, 2008. The results show that both SSP and DSP play a positive role in prediction of mesoscale precipita- tion, such as lowering the （missing） rate of precipitation prediction. SSP is mainly helpful for the 24-hour prediction, while DSP can improve both 24-hour and 48-hour prediction. DSP is better than the two SSPs in the hit rate of regional precipitation prediction. However, the former also has a little higher false alarm rate than the latter. DSP enlarges in some extent the dispersion of EPS, which is good for EPS.
文摘In this paper, we use perturbing families of gernerlized Lyapunov functions to discuss ' the relative stability of ordinary differential systems in terms of two measures and gain some criteria for this stability of asymptotic.'
基金"The System of Ensemble Forecasting Models for Tropical Cyclones in the South China Sea",a project of the Scientific and Technological Plans for Guangdong Province(2003C32603)
文摘A new method, BDA perturbing, is used in ensemble forecasting of typhoon track. This method is based on the Bogus Data Assimilation scheme. It perturbs the initial position and intensity of typhoons and gets; a series of bogus vortex. Then each bogus vortex is used in data assimilation to obtain initial conditions. Ensemble forecast members are constructed by conducting simulation with these initial conditions. Some cases of typhoon are chosen to test the validity of this new method and the results show that： using the BDA perturbing method to perturb initial position and intensity of typhoon for track tbrecast can improve accuracy, compared with the direct use of the BDA assimilation scheme. And it is concluded that a perturbing amplitude of intensity of 5 hPa is probably more appropriate than 10 hPa if the BDA perturbing method is used in combination with initial position perturbation.
文摘为提高系统的能量利用率和运行可靠性,提出了一种用于电流源逆变器(current source inverter,CSI)光伏并网系统最大功率跟踪(maximum power point tracking,MPPT)方法。该方法通过扰动电阻代替传统扰动观察法中扰动电流实现CSI光伏系统的MPPT,有效避免了传统扰动电流MPPT法存在的最大功率点右侧电流易于失控和功率瞬时跌落的问题。实验结果表明,该扰动电阻MPPT(perturbing resistance MPPT,PR-MPPT)法应用于CSI光伏并网系统,能够有效实现系统的最大功率运行。
