在光伏发电系统中,MPPT(maximum power point tracking)的控制算法一直是重点研究的课题之一。根据光伏发电的特性[1],在传统算法的基础上提出了一种全新的控制算法——基于dP/de的MPPT算法。从理论推导和控制算法两方面验证了这种算法...在光伏发电系统中,MPPT(maximum power point tracking)的控制算法一直是重点研究的课题之一。根据光伏发电的特性[1],在传统算法的基础上提出了一种全新的控制算法——基于dP/de的MPPT算法。从理论推导和控制算法两方面验证了这种算法在控制精度和控制速度上均能很好地满足需要。展开更多
A tin film of 320 nm in thickness on Cu foil and its composite film with graphite of-50 nm in thickness on it were fabricated by magnetron sputtering. The surface morphology, composition, surface distributions of allo...A tin film of 320 nm in thickness on Cu foil and its composite film with graphite of-50 nm in thickness on it were fabricated by magnetron sputtering. The surface morphology, composition, surface distributions of alloy elements, and lithium intercalation/de-intercalation behaviors of the fabricated films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, electron probe microanalyzer （EPMA）, X-ray photoelectron spectroscopy （XPS）, inductively coupled plasma atomic emission spectrometry （ICP）, cyclic voltammetry （CV）, and galvanostatic charge/discharge （GC） measurements. It is found that the lithium intercalation/de-intercalation behavior of the Sn film can be significantly improved by its composite with graphite. With cycling, the discharge capacity of the Sn film without composite changes from 570 mAh/g of the 2nd cycle to 270 mAh/g of the 20th cycle, and its efficiency for the discharge and charge is between 90% and 95%. Nevertheless, the discharge capacity of the composite Sn/C film changes from 575 mAh/g of the 2nd cycle to 515 mAh/g of the 20th cycle, and its efficiency for the discharge and charge is between 95% and 100%. The performance improvement of tin by its composite with graphite is ascribed to the retardation of the bulk tin cracking from volume change during lithium intercalation and de-intercalation, which leads to the pulverization of tin.展开更多
In this paper, we propose a new en /de coding scheme of spreading time OCDMA utilizing the dispersion of grating and filter in frequency domain. The key components of the scheme are grating pair, Fourier transformat...In this paper, we propose a new en /de coding scheme of spreading time OCDMA utilizing the dispersion of grating and filter in frequency domain. The key components of the scheme are grating pair, Fourier transformation lens, phase filter etc. The results of design and calculation are shown that the spreading time of input pulse can be up to nanosecond duration and the phase filter can provide pseudo noise bursts in time domain. The requirements for Laser and optical detection equipment in the scheme are reduced. So the new scheme proposed by us is effective for OCDMA en /de coding of coherent ultra short pulses.展开更多
A novel thermo-responsive hydrogel column, featured with both ends of linear poly（N- isopropylacrylarnide） （PNIPAM） chains being grafted onto cross-linked PNIPAM chains, was reported. The laterally sandwich-typed ...A novel thermo-responsive hydrogel column, featured with both ends of linear poly（N- isopropylacrylarnide） （PNIPAM） chains being grafted onto cross-linked PNIPAM chains, was reported. The laterally sandwich-typed hydrogel columns were fabricated by radical polymerization in a three-step process using a method of ice-melting synthesis. The initiating path, morphology and thermoresponsive characteristics of the prepared hydrogel columns were experimentally studied. The results show that the hydrogel column obtained by the initiator inside part has more quick swelling and deswelling rates responsing to temperature cycling than other hydrogels owing to linear PNIPAM chains to form supermacroporous structure. The proposed hydrogel structure provide a new mode of the phase transition behavior for thermo-sensitive ＂smart＂ or ＂intelligent＂ monodisperse micro-actuators, which is highly attractive for targeting drug delivery systems, chemical separations, and sensors and so on.展开更多
突发公共事件期间病人涌入导致重症医学科(intensive care unit, ICU)救治效率降低。为综合评估病人床位分配策略提升ICU救治效率的效果,采用智能体建模-离散事件仿真(agent-based modeling-discrete event simulation, ABM-DES)方法构...突发公共事件期间病人涌入导致重症医学科(intensive care unit, ICU)救治效率降低。为综合评估病人床位分配策略提升ICU救治效率的效果,采用智能体建模-离散事件仿真(agent-based modeling-discrete event simulation, ABM-DES)方法构建ICU救治系统仿真模型。以武汉大学人民医院综合性ICU为例,引入急诊科分区管理策略设计4种差异化床位分配方案,同时从病人、医护人员、物资和空间多维度出发,采用熵权逼近理想解排序法(technique for order preference by similarity to an ideal solution, TOPSIS)法构建ICU救治效率评价体系对多种病人到达模式下的救治效率进行量化评估,筛选最优床位分配方案。结果表明:病人到达模式显著影响最优床位分配方案;分区管理策略的增效作用仅体现在长期大量病人到达场景。研究结果可为ICU应对突发公共事件提供重要参考。展开更多
文摘在光伏发电系统中,MPPT(maximum power point tracking)的控制算法一直是重点研究的课题之一。根据光伏发电的特性[1],在传统算法的基础上提出了一种全新的控制算法——基于dP/de的MPPT算法。从理论推导和控制算法两方面验证了这种算法在控制精度和控制速度上均能很好地满足需要。
基金the National Nature Science Foundation of China (Nos. 50771046 and 20373016) the Natural Science Foundation of Guangdong Province (No. 05200534)the Key Projects of Guangdong Province and Guangzhou City, China (Nos. 2006A10704003 and 2006Z3-D2031)
文摘A tin film of 320 nm in thickness on Cu foil and its composite film with graphite of-50 nm in thickness on it were fabricated by magnetron sputtering. The surface morphology, composition, surface distributions of alloy elements, and lithium intercalation/de-intercalation behaviors of the fabricated films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, electron probe microanalyzer （EPMA）, X-ray photoelectron spectroscopy （XPS）, inductively coupled plasma atomic emission spectrometry （ICP）, cyclic voltammetry （CV）, and galvanostatic charge/discharge （GC） measurements. It is found that the lithium intercalation/de-intercalation behavior of the Sn film can be significantly improved by its composite with graphite. With cycling, the discharge capacity of the Sn film without composite changes from 570 mAh/g of the 2nd cycle to 270 mAh/g of the 20th cycle, and its efficiency for the discharge and charge is between 90% and 95%. Nevertheless, the discharge capacity of the composite Sn/C film changes from 575 mAh/g of the 2nd cycle to 515 mAh/g of the 20th cycle, and its efficiency for the discharge and charge is between 95% and 100%. The performance improvement of tin by its composite with graphite is ascribed to the retardation of the bulk tin cracking from volume change during lithium intercalation and de-intercalation, which leads to the pulverization of tin.
文摘In this paper, we propose a new en /de coding scheme of spreading time OCDMA utilizing the dispersion of grating and filter in frequency domain. The key components of the scheme are grating pair, Fourier transformation lens, phase filter etc. The results of design and calculation are shown that the spreading time of input pulse can be up to nanosecond duration and the phase filter can provide pseudo noise bursts in time domain. The requirements for Laser and optical detection equipment in the scheme are reduced. So the new scheme proposed by us is effective for OCDMA en /de coding of coherent ultra short pulses.
基金the National Natural Science Foundation of China (No.20976202)the Natural Science Foundation of Hubei Province (No.2009CDB161)
文摘A novel thermo-responsive hydrogel column, featured with both ends of linear poly（N- isopropylacrylarnide） （PNIPAM） chains being grafted onto cross-linked PNIPAM chains, was reported. The laterally sandwich-typed hydrogel columns were fabricated by radical polymerization in a three-step process using a method of ice-melting synthesis. The initiating path, morphology and thermoresponsive characteristics of the prepared hydrogel columns were experimentally studied. The results show that the hydrogel column obtained by the initiator inside part has more quick swelling and deswelling rates responsing to temperature cycling than other hydrogels owing to linear PNIPAM chains to form supermacroporous structure. The proposed hydrogel structure provide a new mode of the phase transition behavior for thermo-sensitive ＂smart＂ or ＂intelligent＂ monodisperse micro-actuators, which is highly attractive for targeting drug delivery systems, chemical separations, and sensors and so on.
文摘突发公共事件期间病人涌入导致重症医学科(intensive care unit, ICU)救治效率降低。为综合评估病人床位分配策略提升ICU救治效率的效果,采用智能体建模-离散事件仿真(agent-based modeling-discrete event simulation, ABM-DES)方法构建ICU救治系统仿真模型。以武汉大学人民医院综合性ICU为例,引入急诊科分区管理策略设计4种差异化床位分配方案,同时从病人、医护人员、物资和空间多维度出发,采用熵权逼近理想解排序法(technique for order preference by similarity to an ideal solution, TOPSIS)法构建ICU救治效率评价体系对多种病人到达模式下的救治效率进行量化评估,筛选最优床位分配方案。结果表明:病人到达模式显著影响最优床位分配方案;分区管理策略的增效作用仅体现在长期大量病人到达场景。研究结果可为ICU应对突发公共事件提供重要参考。
