直流激励的大气压氩气喷枪的光谱研究

利用正高压驱动空心针-板喷枪装置,通入工作气体氩气,在大气压空气中产生了均匀稳定的喇叭状等离子体羽。电学和光学测量结果表明,放电虽然是在直流电源驱动下工作,但放电为周期性的脉冲。通过对等离子体羽发光信号进行空间分辨测量,研究了脉冲的形成机理,发现除针尖附近的电晕放电外,等离子体羽是以正流光(等离子体子弹)从针尖向着接地电极方向传播的。采用光谱学方法,对电子激发温度随电压的变化及其空间分布进行了测量。结果表明,电子激发温度(约为3 eV)随电压的增大而升高,在一定电压下,电子激发温度沿气流方向也在升高。     

Generating a uniform transverse distributed electron beam along a beam line

It has been reported that transverse distribution shaping can help to further enhance the energy extraction efficiency in a terawatt, tapered X-ray free-electron laser. Thus, methods of creating and keeping an almost uniform transverse distributed(UTD) beam within undulators are required. This study shows that a UTD electron beam can be generated within evenly distributed drift sections where undulators can be placed, by means of octupoles and particular optics. A specific design is presented, and numerical simulations are performed to verify the proposed method.     

均匀高压电场强化R123池沸腾传热实验研究

利用EHD技术进行了工质R123的池内平板沸腾强化传热实验研究.在该实验中,换热面为一平板并接地作为0电极,高压电极为平行于换热面的网状电极.实验结果表明,正电压的强化效果较好,电压越高,强化效果越好.低热流密度下,EHD对沸腾换热的强化效果比高热流密度的强化效果好.起沸点随着电压的增加而增加,同不加电压时相比,在20 kV时,起沸点提高了4倍.     

Comparisons of mixed systems with decreasing failure rate component lifetimes using dispersive order

Because lifetimes of systems are not deterministic, partially, orders are used for comparison purposes which lead us to provide optimal system configurations. This paper deals with a signature‐based dispersive ordering of mixed systems. It is assumed that component lifetimes are independent and identically distributed, and the common distribution has a decreasing failure rate function. Some illustrative examples are also given.     

天目铁木愈伤组织和芽苗诱导技术

以天目铁木嫩茎尖为外植体,应用均匀设计法筛选其基部愈伤组织诱导和愈伤组织再分化芽苗的最适合培养基.结果表明,最适合的嫩茎尖基部愈伤组织诱导培养基为1/2DR+TDZ 2.30 mg·L^-1+2,4-D 0.55 mg·L^-1,诱导率为93.5%;愈伤组织芽苗再分化培养基为1/2DR+TDZ 3.30 mg·L^-1+KT 0.70 mg·L^-1,分化率达99.8%以上. 成功建立了天目铁木嫩茎尖离体诱导愈伤组织和芽苗再分化体系,且再生芽苗与野生植株染色体数目相同.     

Sufficient conditions of the various stabilities of the linear time-varying delayed differential equations

Due to the appearance and the study of the ornithopter and flexible-wing micro air vehicles, etc., the time-varying systems become more and more important and ubiquitous in the study of the mechanics. In this letter, the sufficient conditions of the uniform asymptotic stability are first presented for the delayed time-varying linear differential equations with any time delay by employing the Dini derivative, Lozinskii measure and the generalized scalar Halanay delayed differential inequality. They are especially based on the estimation of the arbitrary solutions but not the fundamental solution matrix since their solutions' space is infinite-dimensional. Then some sufficient conditions of the stability, asymptotic stability and uniform asymptotic stability of the delayed time-varying linear system with a sufficiently small time delay are reported by employing Taylor expansion and Dini derivative. It implies that these stabilities can be guaranteed by the Lozinskii measure of the matrix composing of the time delay and the coefficient matrices of the system.     

基于忆阻的时滞神经网络的全局稳定性

忆阻是近年来新发现的一类非线性电子元件．与通常的电阻不同,忆阻的阻值会随着通过的电流量的大小和方向不同而改变．这个特性使得忆阻具有了记忆的功能,在很多方面有着广泛的应用．该文给出了简化的忆阻的数学模型,基于该模型构造了时滞神经网络,利用微分包含理论、Lyapunov方法和同胚映射原理研究了其全局渐近稳定性问题,确保模型平衡点存在性、唯一性和一致全局渐近稳定性的充分条件被获得．最后提供的具有仿真的例子验证了获得的理论结果．     

由苯胺二聚体电化学制备聚苯胺的形貌可控性初探

以苯胺二聚体（N-phenyl-p-phenylenediamine）为起始单体,在1 mol·L^-1高氯酸水-乙腈混合液中,玻碳电极表面电化学制备聚苯胺. 实验结果表明,苯胺二聚体单体的聚合电位比苯胺单体的低约0.2 V,并且其聚合物具有更高的形貌可控性. 苯胺二聚体单体浓度分别为1、5和10 mmol·L^-1时,采用分步恒电流法可分别制备出形貌均一的聚苯胺纳米粒子（粒径30 nm）、超长的纳米线（> 5 μm 直径50 nm）和大面积纳米片（4 μm × 2 μm × 30 nm）.     

基于三角小波的弹性薄板高精度分析方法

采用同时具有三角函数良好逼近特性和小波多分辨率与局部特性的Hermite插值型三角小波,基于二维张量积三角小波,推导了求解各种不同边界条件下的矩形弹性薄板的弯曲、振动和屈曲问题的统一列式,同时给出了两种提高计算精度的方法一升阶法和多分辨率法。数值算例表明,三角小波法求解弹性薄板的弯曲、振动和屈曲问题时,能方便地处理各类边界条件,计算效果良好;自振特性分析更具优势,升阶法和多分辨率法能有效地提高分析精度。     

Continuously Dislocated Elastic Bodies with a Neo-Hookean Like Energy Subjected to Anti-plane Shear

In this paper, we consider a materially uniform but inhomogeneous body and we are interested in three particular cases of inhomogeneities corresponding to three distinct distributions of dislocations. The field of defects enters the equilibrium equations through the components of the tensor field describing the relaxation procedure. We examine what form should these components take in order for the material to admit states of anti-plane shear. The results obtained in this paper hold for a class of materials that obey a specific form for the stored energy function. In the special case of no dislocations, this class falls under the well known class of Neo-Hookean materials.