微量希土的螯合滴定

直接或间接螯合滴定常量希土元素已有评述^[1].但有关微量希土元素的螯合滴定之报导不多,Flaschka^[2]曾借铬黑T等作指示剂于直接或间接滴定少量轻希土元素和钇.程广禄^[3]曾报告借PAN作指示剂,以铜返滴定微量希土元素.Лауэр等^[4]曾借纸层析法分离后,继以偶氮胂作指示剂,用氯化镧溶液返滴定以测定个别希土元素.     

三维SPH程序及其在斜高速碰撞问题的应用

叙述了平滑粒子流体动力学(简称SPH)的基本概念,重新推导了所用的基本方程。介绍了具体计算格式、算法以及策略等。对所编制的程序作了一定的检验。对SPH方法中的人为粘性和人为热流的作用作了数值考查。还提供了一个三维高速碰撞现象的算例。最后指出尚存在的若干问题。     

STRESS ANALYSIS IN CUBIC BORON NITRIDE FILMS BY X-RAY DIFFRACTION USING sin2 ψ METHOD

The boron nitride (BN) films containing cubic boron nitride (c-BN) and hexagonal boron nitride (h-BN) were prepared by radio frequency a ssisted thermal filament chemical vapor deposition. The stress and strain in BN films were investigated by X-ray diffraction analysis using the sin² ψ method. The results showed that both c-BN and h-BN in the same film have similar values of elastic strain, however, the compressive stress in c-BN is much greater than that in h-BN for the same film. Both stress and strain gradually decre ased with the increase of substrate temperature (T_s). The effective stress in the films calculated by the effective stress model increased with the increase of T_s. Furthermore, the dependence of effective stress in the films on T_s was also investigated.     

Strong spin frustration and magnetism in kagomé antiferromagnets LnCu3(OH)6Br3(Ln = Nd,Sm, and Eu)

To study the effects of lanthanide ions on the geometrically frustrated antiferromagnets and their magnetic properties,we grew high-quality single crystals of LnCu₃(OH)₆Br₃(Ln=Nd,Sm,and Eu) by hydrothermal method and studied their crystal structures and magnetic properties.The refinements of the crystal structure referred to the powder x-ray diffraction data show that LnCu₃(OH)₆Br₃ adopt a Kapellasite-type layer structure,which is...     

煤矿员工离职倾向影响因素实证研究:以沈煤集团红阳三矿为例

随着煤炭市场的不景气,作为东北地区年产煤量最高的沈煤集团红阳三矿,也出现了员工储备不足和员工流动过于频繁的问题,因此,如何降低员工的流失率成为了企业亟需解决的问题。对于员工离流失问题,首先从理论上进行梳理,根据理论结果和红阳三矿自身特点,设计了员工离职倾向问题调查问卷.然后,应用多分类Logistic模型对数据进行分析,得到员工的离职倾向主要与工作年限、个人收入占家庭收入的比例、工作安全感、发展空间和工资福利待遇有关.最后提出了企业对员工进行帮扶、加强员工安全培训和提升人力资源管理水平等对策建议.     

近红外透射光谱法测定丹酚酸提取物中的丹酚酸B

利用近红外光谱仪透射光谱技术对丹酚酸提取物中丹酚酸B含量进行检测分析。利用42份样品的原始光谱经一阶导数技术预处理,选取9746.9—7498.2、6101.9—5774.1cm-1及4601.5—4424.1cm-1波段,并结合偏最小二乘法(PLS)对丹酚酸B建立定量校正模型并分析,结果R2为0.9843,内部交叉验证均方差(RM SECV)为0.0725,最佳维数为8。用建立的校正模型对17份样品中的丹酚酸B进行了预测,预测误差均方差(RM SEP)为0.0847。该方法分析快速、简便,结果准确可靠,同时也为近红外技术应用于生产过程中的在线监控奠定了基础。     

Integrable KP Coupling and Its Exact Solution

The integrable coupling is one of the most important topics in the nonlinear physics. This paper creates a novel integrable KP coupling and solves it via a recently-developed dark parameterization procedure.     

强激光与近临界密度等离子体相互作用中的无碰撞静电冲击波产生

本文通过一维粒子模拟(particle-in-cell)方法研究了强激光与近临界密度等离子体相互作用中的弱冲击波和强冲击波产生,并讨论了非相对论和相对论光强以及等离子体密度分布区间对无碰撞冲击波形成的影响.非相对论的弱驱动光与等离子体相互作用产生的是弱冲击波.由于电子加热不充分,电子能谱呈现出双温分布.较低温度的电子对弱冲击波的形成以及质子反射加速有重要作用.弱冲击波加速质子的能谱呈连续分布.在等离子体密度上升沿区间较大时,可观察到后孤子结构向离子声波结构演化并进一步演化为弱冲击波结构的过程.在相对论的强驱动光强下,电子加热比较充分可达到相对论温度,且呈现出单温分布.进一步分析密度分布区间大小对冲击波形成的影响时发现:1)当等离子体密度上升沿区间较大时,离子声波的势垒易被热电子屏蔽且离子声波结构在传输的过程中容易被后续的激光破坏而无法演化为无碰撞冲击波;2)当等离子密度分布区间较小时,离子声波中加速电场的有效距离(即德拜长度)和持续时间更长,这导致其结构在传输过程中更加稳定.当离子声波中加速的质子与靶后鞘层场加速的质子之间的速度差满足无碰撞冲击波的离子反射条件时,离子声波进一步演化为强...     

Dark Korteweg–De Vrise System and Its Higher-Dimensional Deformations

The new dimensional deformation approach is proposed to generate higher-dimensional analogues of integrable systems. An arbitrary(K+1)-dimensional integrable Korteweg–de Vries(Kd V) system, as an example, exhibiting symmetry, is illustrated to arise from a reconstructed deformation procedure, starting with a general symmetry integrable(1+1)-dimensional dark Kd V system and its conservation laws. Physically, the dark equation systems may be related to dark matter physics. To describe nonlinear ph...     

光滑圆柱拉伸试件的颈缩分析

对Gurson本构方程作了初步的研究，并对圆柱光滑拉伸试件在颈缩阶段用Gurson本构方程做了大应变弹塑性有限元分析。讨论了颈缩区空穴形核、扩张、静水应力以及材料软化的问题，初步揭示了空穴的演化过程和材料的破坏机理。有限元分析的结果表明，颈缩阶段空穴长大聚合机理非常显著，而形核作用相对较弱。