2-Aminoethoxydiphenyl borate (2-APB) inhibits capacitative calcium entry independently of the function of inositol 1,4,5-trisphosphate receptors

Capacitative calcium entry (CCE), the mechanism that replenishes intracellular calcium stores after depletion, is essential to intracellular calcium signaling. CCE is mediated by the channels in the plasma membrane generally referred to as "store operated channels (SOCs)". However, the molecular identity of the SOCs has never been determined, and the mechanism of the activation of SOCs remains to be elucidated. Recent studies have demonstrated that 2-aminoethoxydiphenyl borate (2-APB), which has been found to be an antagonist of inositol 1,4,5-trisphosphate receptors (IP3Rs), inhibits CCE, suggesting that IP3Rs channel activity is essential to the generation of CCE. However, CCE has also been reported to occur normally in IP3R-deficient cells. In order to resolve this discrepancy, we investigated the effect of 2-APB on CCE in IP3Rs-deficient cells. In response to store depletion with thapsigargin or N,N,N',N'-tetrakis (2-pyridylmethyl) ethylene diamine (TPEN), CCE was generated in IP3Rs-deficient cells the same as in wild-type cells, however, 2-APB abolished CCE in IP3Rs-deficient cells, despite the fact that this cell line does not possess functional IP3Rs. We also examined the effect of 2-APB on several types of TRP Ca2+ channels, which exhibit properties similar to those of SOCs. 2-APB had a different inhibitory effect on spontaneous and thapsigargin-induced Ba2+ influx in cells that transiently expressed individual TRP subtypes. These results suggest that the channel activity of IP3Rs is not essential to the generation of CCE in this cell line and that 2-APB inhibits CCE independently of the function of IP3Rs.     

Dopplerlet based time-frequency representation via matching pursuits

A new time-frequency representation called Dopplerlet transform, which uses the dilated, translated and modulated windowed Doppler signals as its basis functions, is proposed, and the Fourier transform, short-time Fourier transform (including Gabor transform), wavelet transform, and chirplet transform are formulated in one framework of Dopplerlet transform accordingly. It is proved that the matching pursuits based on Dopplerlet basis functions are convergent, and that the energy of residual signals yielded in the decomposition process decays exponentially. Simulation results show that the matching pursuits with Dopplerlet basis functions can characterize compactly a nonstationary signal.     

Unified constant-frequency integration control of active powerfilters-steady-state and dynamics

An active power filter (APF) is a device that is connected in parallel to and cancels the reactive and harmonic currents from a group of nonlinear loads so that the resulting total current drawn from the AC mains is sinusoidal. This paper presents a unified constant-frequency integration (UCI) APF control method based on one-cycle control. This method employs an integrator with reset as its core component to control the pulse width of an AC-DC converter so that its current draw is precisely opposite to the reactive and harmonic current draw of the nonlinear loads. In contrast to previously proposed methods, there is no need to generate a current reference for the control of the converter current, thus no need for a multiplier and no need to sense the AC line voltage, the APF current, or the nonlinear load current. Only one AC current sensor is used to sense the AC main current and one DC voltage sensor is used to sense the DC capacitor voltage. The control method features constant switching frequency operation, minimum reactive and harmonic current generation, and simple analog circuitry. It provides a low cost and high performance solution for power quality control. Steady-state and dynamic study is presented in this paper. Design example is given using a two-level AC-DC boost topology. A prototype was developed to demonstrate the performance of the proposed APF. This control method is generalized to control a family of converters that are suitable for APF applications. All findings are supported by experiments and simulation     

全业务网APON光纤接入传输系统

介绍在国家八六三计划资助下研制成功的全业务网接入传输系统 ,首先简述了系统构成、用户业务接口和传输帧结构 ,接着对 HFC双向光纤传输系统进行了简介 ,最后介绍了 ATM- PON系统和HFC系统的性能指标     

ATM复用交叉连接系统设计和实现

给出了一种 ATM复用交叉连接系统的设计方法 ;描述了采用该方法设计完成的 ATM交叉连接系统的构成 ,给出了它所达到的性能指标及实验测试结果 ;该系统可以应用于数字用户环路接入复用器 (DSL AM)、ATM无源光网络 (APON)、无线接入、帧中继接入系统等多种应用场合。     

主动防御新技术及其在电力信息网络安全中的应用

随着信息化技术的不断发展和普及,构建信息网络系统提高了人们的工作效率,也改变了人们的工作方式,在各个行业中都起到了非常好的促进作用.本文就电力信息网络安全存在的问题,对主动防御技术进行相应的分析,并对主动防御技术在电力信息网络安全中的应用进行相应的探讨.希望为电力网络安全的发展提供一些有用的建议.     

基于实测的WLAN系统导频位置优化设计

针对IEEE 802.11ac“利用前导序列符号+梳状导频”的帧结构,推导出基于最大似然估计的校正方案性能评估公式。基于该公式分析了导频位置选择、信道衰落及子载波间相关性对校正性能的影响。提出了一种信令交换方式,可以实现收发端优化导频位置同步,并根据信道响应的幅度信息,设计了一种低复杂度的导频位置优化的方案,能够在保证性能不损失的情况下,节省导频开销。仿真与实测的结果显示,对于理想瑞利信道数据,校正性能在信道幅度信息未知和已知的情况下分别提升1.85 dB和7.15 dB;对于实测信道数据,则分别提升1.67 dB和2.68 dB。     

基于FDS的地下单室火灾模拟验证实验

为了验证火灾模拟软件FDS(Fire Dynamics Simulator)的准确性,针对地下建筑单室特点,选取某工程内一个值班室作为研究对象,并根据相似准则建立了小尺度火灾房间模型。通过小尺度单室火灾实验,对烟气的扩散特性进行研究,同时利用FDS模拟软件进行单室火灾模拟,并将实验结果与模拟结果进行对比分析。结果表明,实验烟气温度随时间的变化趋势与FDS模拟结果一致,验证了火灾模拟软件FDS的准确性,证实了FDS用于模拟预测单室火灾的发展与迁移的适用性和合理性,对火灾的控制研究具有一定的参考价值。     

基于谱逼近的瞬态极化雷达最优波形设计

针对瞬态极化雷达(IPR)两路极化波形相关度较高而导致的目标极化参数估计误差大的问题,该文提出纯相位谱逼近算法(POSAA)来设计具有低相关水平的波形对。首先,以积分旁瓣电平准则构建目标函数;然后利用相关与谱的傅里叶变换对关系,基于谱逼近的思想,推导了目标函数的频域表示;最后获得目标函数的梯度和Hess矩阵,并采用信赖域方法优化求解目标函数以获得理想波形。仿真结果表明优化后的波形对具有极低的相关水平,且利用该优化波形获得的目标参数误差远小于当前常见波形。     

FeO0.7F1.3/C Nanocomposite as a High‐Capacity Cathode Material for Sodium‐Ion Batteries

Searching high capacity cathode materials is one of the most important fields of the research and development of sodium‐ion batteries (SIBs). Here, we report a FeO_0.7F_1.3/C nanocomposite synthesized via a solution process as a new cathode material for SIBs. This material exhibits a high initial discharge capacity of 496 mAh g^?1 in a sodium cell at 50 °C. From the 3^rd to 50^th cycle, the capacity fading is only 0.14% per cycle (from 388 mAh g^?1 at 3^rd the cycle to 360 mAh g^?1 at the 50^th cycle), demonstrating superior cyclability. A high energy density of 650 Wh kg^?1 is obtained at the material level. The reaction mechanism studies of FeO_0.7F_1.3/C with sodium show a hybridized mechanism of both intercalation and conversion reaction.