三轴压缩条件下胶结充填体能量耗散特征分析

开展不同灰砂配比、质量分数的充填体三轴压缩试验,研究了不同围压加载阶段充填体的能量耗散与围压、应变以及应力的内在关系.结果表明,在低围压时,充填体的极限抗压强度低;随着围压的增加,充填体的峰值强度随之增大,峰前能耗占总能耗的比重越来越大,说明充填体屈服阶段吸收的能量占总能量的比重提高,围压的增大能够提高充填体的破坏能耗量;充填体的峰前能耗量、峰后能耗量、单位体积变形能以及总能耗与围压呈二次函数曲线关系.当围压一定时,充填体在弹性变形阶段的能量变化与轴向应力、偏应力均呈线性关系,与轴向应变呈指数函数曲线关系;随着轴向载荷增加,能量随轴向应力、偏应力变化的增长速率加大.     

斜视圆迹环扫SAR模式特性分析及成像方法简

Circular scanning SAR(CSSAR) is a new mode for fast large area SAR imaging by increasing the azimuth scanning speed. The squint CSSAR possesses the advantages that the side-looking CSSAR does not have due to its unique observing direction. However, the available signal characteristic analysis and imaging method for side-looking CSSAR become questionable when applied to the squint CSSAR. This paper establishes the echo range model and analyzes several parameters such as azimuth scanning speed, Doppler characteristics and azimuth resolution according to the moving feature of squint CSSAR. Furthermore, the internal relationship between the squint CSSAR and the classical stripmap mode is revealed. The range approximation model as well as the corresponding imaging method is analyzed. Computer simulation results validate the conclusions and the imaging method.     

灵敏负荷在配电网控制中的约束条件和容量估算

论述了配电网中的灵敏负荷,作为资源的灵敏负荷所具有的特点,给出了灵敏负荷控制系统的示意图。重点讨论了灵敏负荷优化控制约束条件以及相关的数学模型,即在考虑某些实际问题的情况下,给出了灵敏负荷最优控制的约束条件,设定了关闭和正常运行两种状态的约束关系,在限定的必要条件下,求解最优化目标函数。以沈阳市为例,根据所测日负荷数据分析曲线图,对灵敏负荷的容量进行了估算,对于指导灵敏负荷控制起到重要的作用和实用效果。利用好灵敏负荷资源,对提高电力系统的稳定性,降低运行成本有着重要的实际意义。     

高电位CuV_2O_6正极材料在热电池中的应用

采用固相法以CuO粉末和V2O5粉末为原料制备α-CuV2O6粉末,用X射线衍射分析(XRD)、差热分析(DTA)和粒度分析方法对铜钒氧材料进行了表征,并对其作为热电池正极材料的电化学行为进行了研究。电化学性能测试表明,制备的α-CuV2O6电极单体电池具有较高的放电电压和较大的放电比容量。     

包头某越冬基坑桩锚支护结构受力变形监测分析

近几年基坑支护深度H不断增加,施工周期也不断变长,在北方一些寒冷地区,一些基坑工程不得不进入越冬期.由于基坑渗水和地下水的影响,基坑土体的冬季冻胀和春季融陷容易对支护结构产生一些不良作用.针对包头某越冬基坑进行了监测,总结了桩锚支护结构在越冬时锚杆轴力变化和基坑位移变化,并提出了一些防治冻胀的措施,为类似工程提供参考.     

Stability of long trench in soft soils by bentonite-water slurry

A series of centrifuge model tests exploring the effects of different types of slurry on long-trench stability in soft clay were conducted. The influence of groundwater conditions relative to trench stability was examined by constructing long trenches using different slurries. The soil deformation and surface settlement induced by the excavation of the trench are found to be closely related to slurry type and excavation depth of the long trench. Increasing the bentonite concentration of the slurry has beneficial effects on stability： 1） larger particles can improve local and global stability in cases where filter cakes do not form, and 2） larger viscosity can promote filter cake formation on the walls of long trenches excavated in soft clay and enhance their stability.     

An investigation on electrochemical performances of as-cast and annealed La0.8Mg0.2Ni3.3Co0.2Six（x = 0-0.2） alloy electrodes for Ni/MH battery application

The La-Mg-Ni-based A2B7-type La0.5Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prepared by casting and annealing. The influences of the additional silicon and the annealing treatment on the structure and electrochemical performances of the alloys were investigated systemically. Both of the analyses of XRD and SEM reveal that the as-cast and annealed alloys are of a multiphase structure, involving two main phases （La, Mg）2Ni7 and LaNi5 as well as one minor phase LaNi3. The addition of Si and annealing treatment bring on an evident change in the phase abundances and cell parameters of （La, Mg）2Ni7 and LaNi5 phase for the alloy without altering its phase structure. The phase abundances decrease from 74.3% （x=0） to 57.8% （x=0.2） for the （La, Mg）2Ni7 phase, and those of LaNi5 phase increase from 20.2% （x~0） to 37.3% （x=0.2）. As for the electrochemical measurements, adding Si and performing annealing treatment have engendered obvious impacts. The cycle stability of the alloys is improved dramatically, being enhanced from 80.3% to 93.7% for the as-annealed （950 ℃） alloys with Si content increasing from 0 to 0.2. However, the discharge capacity is reduced by adding Si, from 399.4 to 345.3 mA.h/g as the Si content increases from 0 to 0.2. Furthermore, such addition makes the electrochemical kinetic properties of the alloy electrodes first increase and then decrease. Also, it is found that the overall electrochemical properties of the alloys first augment and then fall with the annealing temperature rising.     

Kinetics study of leaching arsenic from Ni-Mo ore roasting in dust mixture of hydrochloric and sulfuric acids

The kinetics of leaching arsenic from Ni-Mo ore roasting dust was investigated. The effects including leaching temperature, particle size of the smelter dust, stirring speed, the coefficient β（the molar ratio of sodium chlorate to arsenic in the smelter dust） and the initial H＋ concentration on leaching arsenic were studied. The results indicate that the leaching of arsenic increases sharply with the decrease of particle size. The orders of reaction with respect to H＋ concentration and particle size are determinted to be 1.136 and 1.806, respectively. The leaching of arsenic reaches 99% under experimental conditions, the apparent activation energy is determined to be 11.157 kJ/mol, which is consistent with the values of activation energy for diffusion model The kinetics equation of leaching arsenic from the roasting dust could be expressed by a semi-empirical equation as 1-2/3η （1 -η）^2/3 = k0（c[H＋]）^1.136ro^-1.806 exp[（-11157 /RT）t].     

基于行波法的10kV电缆单环网在线故障定位系统

针对电缆单环网故障定位问题,本文以行波理论为基础,对10kV电缆单环网在线故障定位系统进行研究。通过对电缆单环网结构进行分析,将单环网分为不同级别的T型组合单元,对每个T型电缆单元提出具体测距原理及算法,同时对所有的T型单元依次进行测距并统计分析测距结果,汇总后得到单环网的测距结果,并利用电力系统仿真软件(power system computer aided design,PSCAD)对T型单元故障进行仿真,仿真结果验证了算法和判据的可行性与正确性;最后对电缆单环网在线故障定位系统的硬件和软件进行设计。该系统可以实现对10kV电缆单环网故障的在线监测和定位,与其他测距装置相比,可以快速准确地找到故障点,从而减少停电检修时间,确保供电可靠性,有利于提高经济效益。     

二元生成自由群的幂单性质(英文)

为了研究二元生成自由群的幂单性质,依据组合群理论,讨论了本原元素的若干组合方式,证明了可用于处理幂零的几组新方程.证明了可以嵌入一般线性群的二元生成自由群是幂单群的充要条件是它的每个本原元素均是幂单的.