大采高综采支架工作阻力综合分析与确定

通过基于全波形声发射的岩石力学特性参数试验及分析,6.2m大采高综采支架工作阻力物理相似模拟,采用FLAC3D三维有限差分计算分析等方法和手段,分析工作面向前推进过程中上覆岩层的垮落、破断对工作面支架支护阻力的影响,并对模拟支架工作阻力进行了统计分析,确定了合理支护强度或合理支架工作阻力,为羊场湾煤矿6.2m大采高工作面的安全开采和支架工作阻力参数的确定提供了科学的依据。     

基于车辆地面力学沙漠沙结构性本构模型的建立

结合沙漠土壤的三轴试验资料,将岩土力学研究中描述土结构性的定量参数(应变综合结构势)引入土的强度变形特性分析. 根据该参数对同一围压下不同含水率沙的应力-应变曲线具有较好的归一化作用,用类似邓肯-张模型的处理方法构造沙漠沙结构性本构模型,并提出获得模型参数的试验方法. 试验与仿真结果表明该结构模型能较好反映不同含水率下沙漠沙的应力-应变关系.      

不同卷烟接装纸中菌落总数的测定

采用平板计数法测定了10种市售卷烟接装纸的菌落总数,结果表明:(1)平板计数法适用于卷烟接装纸菌落总数的测定;(2)平板计数法检测接装纸菌落数重复性较好,同一稀释度(1:10)平行样检测结果的相对标准偏差(RSD)小于30%,同一样品平行样RSD小于20%;(3)不同接装纸样品差异性显著,同一厂家接装纸样品差异性不显著;(4)所测接装纸中的菌落总数均符合行业限量标准,可判定为合格.     

近年来国内政治语言研究述评

以近年来国内学界关于政治语言相关研究为基础,从政治语言的定义、特征以及功能等角度进行梳理,在评述前人研究成果的基础上,提出政治语言是语言的一种功能变体,是语言在政治领域运用的一种交际形式,并深入探讨其特征和社会功能。同时,本文在分析论述的过程中试图全面地概括该领域的研究现状并试图找到研究的突破点。     

基于小波理论谐波减速器振动信号的降噪研究

为满足频率高时窗口窄、频率低时窗口宽的要求,应用小波分析理论对XB-80-134H型谐波减速器的振动信号进行了分析,利用Daubechies小波对振动信号进行小波分解,并结合阈值去噪方法对信号作了消噪处理,即针对振动信号分解的各层小波系数设定相应的阈值,对于小于该阈值的小波系数认为是噪声并置为零,将剩余的小波系数重构,得到消噪后的振动信号.与传统的傅里叶降噪方法比较结果表明,小波降噪远优于傅里傅里叶降噪方法,小波降噪后的信噪比提高了6dB,而傅里叶降噪只提高了1 dB.     

互补问题的自由导数方法研究

提出了一种新的NCP函数,并将它应用于自由导数方法,达到了提高算法速度的目的.     

微波辐射β分子筛负载SO_4~(2-)/Fe_2O_3固体超强酸催化制备2-(2-1H-苯并咪唑基)-苯酚

以邻苯二胺和水杨酸为原料,β分子筛负载SO2-4/Fe2O3固体超强酸催化剂,微波辐射促进合成了2-(2-1H-苯并咪唑基)-苯酚。实验结果表明:n(水杨酸)∶n(邻苯二胺)=1.0∶1.1(水杨酸6.90 g,邻苯二胺5.70 g),固体超强酸相对用量0.10 g,微波辐射功率500 W,微波辐射时间5 min。产率达87.8%,与常规加热方法相比,具有反应速度快、转化率高等优点。     

Aerodynamic optimization and evaluation for the three-dimensional afterbody/nozzle integrated configuration of hypersonic vehicles

The optimization of 2D expansion lines and key parameters of three-dimensional configurations was carried out under simulated conditions of Mach 6.5 and a flight altitude of 25 km for an integrated configuration of the afterbody/nozzle of a hypersonic vehicle.First,the cubic B-spline method was applied to parameterize the expansion lines of the upper expansion ramp.The optimization procedure was established based on computational fluid dynamics and the sequential quadratic programming method.The local mesh reconstruction technique was applied to improve computational efficiency.A three-dimensional integrated configuration afterbody/nozzle was designed based on the two-dimensional optimized expansion lines.The influence rules incorporated certain key design parameters affecting the lift and thrust performance of the configuration,such as the ratio of the lengths of the lower expansion ramp to the afterbody (l/L),the dip angle of the lower expansion ramp ω,and the ratio of exit height to the length of afterbody (H/L).Under these conditions,we found that the integrated configuration has optimal performance when l/L=1/6,H/L=0.35 and =10°.We also showed that the presence of a side-board promotes lift and thrust performance,and effectively prevents the leakage of high pressure gas.     

Relationship between microstate number and available entransy

Based on the relationship between entransy and microstate number, we discuss the variations of the available transport entransy, the unavailable transport entransy, the available conversion entransy and the unavailable conversion entransy with the microstate number. We focus on physical processes in which heat is used for heating/cooling or doing work. When heat is transported for heating or cooling, the available transport entransy increases if the increase in microstate number is due to the increase in internal energy of the system, and decreases if the increase in microstate number is due to spontaneous heat transfer. When heat is used to do work, both the available conversion entransy and the unavailable conversion entransy increase if the increase in microstate number relates to the growth in internal energy of the system. The available conversion entransy decreases and the unavailable conversion entransy increases if the increase in microstate number results from spontaneous heat transfer.     

Low temperature synthesis of NiO/Co3O4 composite nanosheets as high performance Li-ion battery anode materials

NiO/Co3O4 composite nanosheets have been synthesized via a facile method at low temperature for the first time.The as prepared materials were characterized by X-ray powder diffraction(XRD) and transmission electron microscopy(TEM),and the performance of Li-ion batteries(LIBs) as anode materials were also studied.By controlling the atom ratio of Ni:Co,not only the size of the nanosheets can be controlled,the electrode’s conductivity and stability could also be greatly improved.The composite material showed a stable capacity retention during cycling(87% of the second capacity was retained after 15 cycles) even at a relatively large current rate(400 mA/g).The NiO/Co3O4 nanosheet might be promising candidate anode materials in high performance Li-ion batteries.