无机-有机杂化聚合物电解质的制备与电化学性能

以有机改性聚硅氧烷为单体加入液态电解质通过紫外光辐射固化制备了无机有机杂化聚合物电解质.含有丙烯酸酯端基的有机改性聚硅氧烷单体是通过正硅酸甲酯(TMOS)的水解缩合反应产物与丙烯酸2羟乙酯(HEA)进行脱甲醇反应合成的.它是一种多官能团单体,其结构通过核磁共振氢谱(1HNMR)分析、红外光谱(FTIR)分析及二氧化硅分析进行了表征,分子式可表达为SiO1.143(OH)0.016(OCH3)1.339(OCH2CH2OCOCHCH2)0.357.无机有机杂化聚合物电解质的电化学性能通过交流阻抗和循环伏安法进行了表征.其离子电导率随着液态电解质含量的增大而提高,当液态电解质含量为85wt%时,电导率在22℃为5.5×10-3Scm-1,在-23℃也能达到1.1×10-3Scm-1.界面电阻经过开始2天的增大后达到稳定,电化学稳定窗口超过5.0V,不锈钢电极上锂的电化学沉积与剥离循环可逆性很高.     

NH4HCO3对氧化铝孔结构的影响

ＮａＡｌＯ２溶液和ＣＯ２在低温下成胶,生成的沉淀为无定形氢氧化铝,拟薄水铝石或三水氧化铝;加入一定量的ＮＨ４ＨＣＯ３,控制一定的时间,温度和压力,氢氧化铝与ＮＨ４ＨＣＯ３作用生成片钠铝石ＮＨ４Ａｌ（ＯＨ）２ＣＯ３,经高温焙烧后可制香孔容为０．６－１．５ｍｌ／ｇ的大孔容氧化铝。     

VARIABLE SELECTION BY PSEUDO WAVELETS IN HETEROSCEDASTIC REGRESSION MODELS INVOLVING TIME SERIES

A simple but efficient method has been proposed to select variables in het-eroscedastic regression models. It is shown that the pseudo empirical wavelet coefficients corresponding to the significant explanatory variables in the regression models are clearly larger than those nonsignificant ones, on the basis of which a procedure is developed to select variables in regression models. The coefficients of the models are also estimated. All estimators are proved to be consistent.     

Distributed cooperative control for multiple quadrotor systems via dynamic surface control

This paper addresses the cooperative control problems of multiple quadrotor systems under fixed directed communication topologies. Dynamic surface control (DSC) is utilized to design nonlinear consensus controllers to make multiple quadrotors construct and keep a formation during flying. The control scheme is distributed so that each quadrotor updates the values of its information states based on the information states of its neighbors and its own states. Moreover, the leader–follower case is also discussed. In this case, distributed continuous schemes are also proposed with distributed sliding-mode observers, whose function is to estimate two linear combinations of the leader’s velocity and acceleration accurately in finite time. Finally, the effectiveness of the theoretical results is demonstrated via two examples.     

关于集合上关系合成运算的注记

设R是X上的一个关系,通过构造反例来否定有关文献中给出的结论:RloRm=Rl+m对任何整数l,m成立,其中RoR表示R与自身的合成,简记为R2(Rl,Rm等意义详见正文).进一步,在理论上建立使RloRm=Rl+m对任何整数l,m都成立的等价条件.     

稀土“农乐”益植素的增产效果

稀土农用是国家经委要求的推广项目之一。石河子地区经过三年的小区试验和大面积示范,说明在春小麦的苗期、棉花的初花期喷施稀土“农乐”益植素可以收到明显的增产效果和经济效益。     

On the trigonometric polynomials of Fejér and Young

The trigonometric polynomials of Fejér and Young are defined by $S_n (x) = \sum\nolimits_{k = 1}^n {\tfrac{{\sin (kx)}} {k}}$S_n (x) = \sum\nolimits_{k = 1}^n {\tfrac{{\sin (kx)}} {k}} and $C_n (x) = 1 + \sum\nolimits_{k = 1}^n {\tfrac{{\cos (kx)}} {k}}$C_n (x) = 1 + \sum\nolimits_{k = 1}^n {\tfrac{{\cos (kx)}} {k}}, respectively. We prove that the inequality $\left( {{1 \mathord{\left/ {\vphantom {1 9}} \right. \kern-\nulldelimiterspace} 9}} \right)\sqrt {15} \leqslant {{C_n \left( x \right)} \mathord{\left/ {\vphantom {{C_n \left( x \right)} {S_n \left( x \right)}}} \right. \kern-\nulldelimiterspace} {S_n \left( x \right)}}$\left( {{1 \mathord{\left/ {\vphantom {1 9}} \right. \kern-\nulldelimiterspace} 9}} \right)\sqrt {15} \leqslant {{C_n \left( x \right)} \mathord{\left/ {\vphantom {{C_n \left( x \right)} {S_n \left( x \right)}}} \right. \kern-\nulldelimiterspace} {S_n \left( x \right)}} holds for all n ≥ 2 and x ∈ (0, π). The lower bound is sharp.     

Widely tunable mid-IR difference-frequency generation based on fiber lasers

A wide tuning technique for mid-IR difference-frequency generation (DFG) with uniform grating periodically poled LiNbO(3) (PPLN) is presented. Based on the dispersion property of the PPLN, the quasi-phase matching (QPM) band for the pump can evolve to two separate bands, and the spacing between them can be increased with the decrease of the crystal temperature. Two such separate QPM bands can be used for increasing the idler tuning range when the crystal temperature is set to adapt the pump tuning. With the technique, an idler tuning range of 690nm is experimentally achieved with fiber laser fundamental lights.     

一种远程HPM测量数据采集系统的设计与实现

为获取某型高功率微波辐射系统辐射至空中靶目标处(数十m至数百km处)的微波脉冲参数,基于某升空平台无线数传链路,设计了一种结构简单、紧凑的远程无线高功率微波辐射场测量数据采集系统。该系统具备运行状态动态指示、测量参数远程设置以及波形数据实时显示等功能,质量小于2 kg,瞬时动态范围大于15 dB。试验结果表明：测量系统具备高重频微波脉冲参数测量能力,能实时有效捕获辐射场微波波形,运行稳定可靠,可满足百km级距离上的空中辐射场测量需求。     

Influences of gain broadening on multiwavelength oscillations in YDFLs and EDFLs

We report the comparisons of the influences of gain broadening on multiwavelength oscillations in YDFL and EDFL with typical commercial ytterbium- and erbium-doped Al/Ge silica fibers. Our experimental results show that both the YDF and the EDF exhibit inhomogeneous gain broadening, which allows the lasing lines to increase with the increase of the pump, however, multiwavelength oscillations of the EDFL are more stable than those of the YDFL, in particular, when the wavelength spacing is small. Moreover, the minimum wavelength spacing for stable multiwavelength operations of the YDFL and the EDFL are observed to be 1.0 and 0.8 nm at room temperature, and 0.8 and 0.25 nm at 77 K, respectively. This show that the inhomogeneous gain broadening of the EDF may be stronger than that of the YDF.