According to the signal processing characteristic of MIMO radars,an adaptive dwell scheduling algorithm is proposed.It is based on a novel pulse interleaving technique,which makes full use of transmitting,waiting and ...According to the signal processing characteristic of MIMO radars,an adaptive dwell scheduling algorithm is proposed.It is based on a novel pulse interleaving technique,which makes full use of transmitting,waiting and receiving durations of radar dwells.The utilization of transmitting duration is unique for MIMO radars and is realized through transmitting duration overlapping.Simulation results show that,compared with the conventional scheduling algorithm,the scheduling performance of MIMO radars can be improved effectively by the proposed algorithm,and the scheduling rule can be chosen arbitrarily when using the proposed algorithm.展开更多
1-year hourly wind speed data from two Burundian stations, namely Bujumbura and Muyinga, have been processed in this work to bring an efficient help for the planning and installation of wind energy conversion systems ...1-year hourly wind speed data from two Burundian stations, namely Bujumbura and Muyinga, have been processed in this work to bring an efficient help for the planning and installation of wind energy conversion systems (WECS) at those localities. Mean seasonal and diurnal variations of wind direction and wind shear exponent have been derived. Two-parameter Weibull probability density functions (PDFs) fitting the observed monthly and annual wind speed relative frequency distributions have been implemented. As shown through three complementary statistical tests, the fitting technique was very satisfactory. A wind resource analysis at 10 m above ground level (AGL) has led to a mean power density at Bujumbura which is almost thirteen fold higher than at Muyinga. The use of the empirical power law to extrapolate wind characteristics at heights from 150 to 350 m AGL has shown that energy potential of hilltops around Muyinga was only suitable for small, individual scale wind energy applications. At the opposite, wind energy potential of ridge-tops and hilltops around Bujumbura has been found suitable for medium and large scale electricity production. For that locality and at those heights, energy outputs and capacity factors (CF or C<sub>f</sub>) have been computed for ten selected wind turbines (WTs), together with costs of electricity (COE) using the present value of cost (PVC) method. Amongst those WTs, YDF-1500-87 and S95-2.1 MW have emerged as the best options for installation owing to their highest CF and lowest COE. Moreover, an analysis of those two quantities at monthly basis for YDF-1500-87 WT has led to its best performance in the dry season. Compared to the average present COE of household hydroelectricity consumption, results of this study have evidenced economical feasibility and benefit of WECS setting in selected Burundian sites in order to supplement traditional electricity sources.展开更多
We report on the investigation of intermode beating mode-locked(IBML)pulse generation in a simple all-fiber Tm^3+-doped double clad fiber laser(TDFL).This IBML TDFL is implemented by matching longitudinal-mode frequen...We report on the investigation of intermode beating mode-locked(IBML)pulse generation in a simple all-fiber Tm^3+-doped double clad fiber laser(TDFL).This IBML TDFL is implemented by matching longitudinal-mode frequency between 793 nm laser and TDFL without extra mode locker.The central wavelength of 1983 nm,the fundamental pulse frequency of 9.6 MHz and the signal-to-noise ratio(SNR)of>50 dB are achieved in this IBML TDFL.With laser cavity optimization,the IBML TDFL can finally generate an average output power of 1.03 W with corresponding pulse energy of 107 nJ.These results can provide an easily accessible way to develop compact large-energy,highpower TDFLs.展开更多
为了降低冲击片雷管起爆能量,优化高压脉冲功率源等效参数,研究了高压脉冲功率源等效参数如等效电感、等效电阻、电容量、电压等参数对金属桥箔电爆特性规律的影响,测试了金属桥箔在不同的等效参数条件下,其电爆性能的变化规律参数,计...为了降低冲击片雷管起爆能量,优化高压脉冲功率源等效参数,研究了高压脉冲功率源等效参数如等效电感、等效电阻、电容量、电压等参数对金属桥箔电爆特性规律的影响,测试了金属桥箔在不同的等效参数条件下,其电爆性能的变化规律参数,计算了金属桥箔的能量利用率,实验结果表明:当高压脉冲功率源储能电容容量为0.2μF,放电回路等效电感为57 n H,等效电阻为68 mΩ时,在加载电压为2.0 k V放电条件下,桥区厚度为5.0μm,尺寸为0.5 mm×0.5 mm的铜箔其爆发性能最优,有效能量利用率达到最高,为54.8%,此时桥箔的爆发时间与峰值时间最为接近,时差最小。展开更多
基金supported by the National Natural Science Foundation of China(6110117161032010)
文摘According to the signal processing characteristic of MIMO radars,an adaptive dwell scheduling algorithm is proposed.It is based on a novel pulse interleaving technique,which makes full use of transmitting,waiting and receiving durations of radar dwells.The utilization of transmitting duration is unique for MIMO radars and is realized through transmitting duration overlapping.Simulation results show that,compared with the conventional scheduling algorithm,the scheduling performance of MIMO radars can be improved effectively by the proposed algorithm,and the scheduling rule can be chosen arbitrarily when using the proposed algorithm.
文摘1-year hourly wind speed data from two Burundian stations, namely Bujumbura and Muyinga, have been processed in this work to bring an efficient help for the planning and installation of wind energy conversion systems (WECS) at those localities. Mean seasonal and diurnal variations of wind direction and wind shear exponent have been derived. Two-parameter Weibull probability density functions (PDFs) fitting the observed monthly and annual wind speed relative frequency distributions have been implemented. As shown through three complementary statistical tests, the fitting technique was very satisfactory. A wind resource analysis at 10 m above ground level (AGL) has led to a mean power density at Bujumbura which is almost thirteen fold higher than at Muyinga. The use of the empirical power law to extrapolate wind characteristics at heights from 150 to 350 m AGL has shown that energy potential of hilltops around Muyinga was only suitable for small, individual scale wind energy applications. At the opposite, wind energy potential of ridge-tops and hilltops around Bujumbura has been found suitable for medium and large scale electricity production. For that locality and at those heights, energy outputs and capacity factors (CF or C<sub>f</sub>) have been computed for ten selected wind turbines (WTs), together with costs of electricity (COE) using the present value of cost (PVC) method. Amongst those WTs, YDF-1500-87 and S95-2.1 MW have emerged as the best options for installation owing to their highest CF and lowest COE. Moreover, an analysis of those two quantities at monthly basis for YDF-1500-87 WT has led to its best performance in the dry season. Compared to the average present COE of household hydroelectricity consumption, results of this study have evidenced economical feasibility and benefit of WECS setting in selected Burundian sites in order to supplement traditional electricity sources.
基金supported by the National Natural Science Foundation of China(NSFC)(No.61805124)Natural Science Foundation of Ningbo City,China(No.2018A610023)+1 种基金3315 Innovation Team in Ningbo City,Zhejiang Province,ChinaK.C.Wong Magna Fund in Ningbo University,China。
文摘We report on the investigation of intermode beating mode-locked(IBML)pulse generation in a simple all-fiber Tm^3+-doped double clad fiber laser(TDFL).This IBML TDFL is implemented by matching longitudinal-mode frequency between 793 nm laser and TDFL without extra mode locker.The central wavelength of 1983 nm,the fundamental pulse frequency of 9.6 MHz and the signal-to-noise ratio(SNR)of>50 dB are achieved in this IBML TDFL.With laser cavity optimization,the IBML TDFL can finally generate an average output power of 1.03 W with corresponding pulse energy of 107 nJ.These results can provide an easily accessible way to develop compact large-energy,highpower TDFLs.
文摘为了降低冲击片雷管起爆能量,优化高压脉冲功率源等效参数,研究了高压脉冲功率源等效参数如等效电感、等效电阻、电容量、电压等参数对金属桥箔电爆特性规律的影响,测试了金属桥箔在不同的等效参数条件下,其电爆性能的变化规律参数,计算了金属桥箔的能量利用率,实验结果表明:当高压脉冲功率源储能电容容量为0.2μF,放电回路等效电感为57 n H,等效电阻为68 mΩ时,在加载电压为2.0 k V放电条件下,桥区厚度为5.0μm,尺寸为0.5 mm×0.5 mm的铜箔其爆发性能最优,有效能量利用率达到最高,为54.8%,此时桥箔的爆发时间与峰值时间最为接近,时差最小。
