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利用有限单元法,数值分析轴向柱塞泵缝隙高度可变时阀门板上油膜的压力分布.缝隙中油压变化的确定,通常是应用Pasynkow 润滑理论中的Reynolds方程.使用基于有限单元法的自编程序,数值地求解该方程.为了提高结果的精度,基于解的残差估计,应用了加密的自适应网格.给出了依赖于泵的几何条件和工作参数的计算结果. 相似文献
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§1. IntroductionLet:H:Rn×Rn→RbeasmoothHamiltonfunction(q,p)→H(q,p)G:Rn×Rn→R2nbesmoothoperator(q,p)→G(q,p)=(g1(q,p),…,g2n(q,p)). Wedefinetwospaces:L=span{gi,{H,gi},{H,{H,gi}},…,i=1,2,…,2n}dL(z)={df(z)|f∈L} z∈Rn×Rn.Here{,}ispoissonbracket.Throughoutth… 相似文献
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A power-scaled laser operation of Pr:YLi F4(YLF)crystal at 720.9 nm pumped by a 443.6 nm laser diode(LD)module was demonstrated.The 20 W module was used to pump the Pr:YLF crystal,and a maximum output power of 3.03 W with slope efficiency of 30.04%was obtained.In addition,a 5 W blue LD was also used to pump the Pr:YLF laser,and a maximum output power of 0.72 W was obtained at room temperature.The output power was limited by the wavelength mismatch between the single-emitter LD and the absorption peak of the crystal. 相似文献
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近年来,研究发现反钙钛矿化合物Mn3AX(A=Cu,Zn,Sn,Ni,Al,Ga等;X=N/C)具有超导,巨磁阻,近零电阻温度系数,负膨胀,磁致伸缩,压磁效应,以及磁卡效应等丰富的物理性能,因此此类化合物受到人们越来越多的关注.反钙钛矿Mn3AX化合物的结构和物性的研究,将对我们深入认识材料的"本-构"关系具有重要的意义.本文重点综述了部分反钙钛矿Mn3AX化合物奇特的物理性质,尤其是
关键词:
反钙钛矿
磁相变
负热膨胀
电输运 相似文献
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1引言在盐酸-硫酸-磷酸介质中,用铝粒将Ti(Ⅳ)和Fe(Ⅲ)还原为Ti(Ⅲ)、Fe(Ⅱ),以番红花红T-靛红为指示剂用硫酸铈滴定Ti(Ⅲ)可获得敏锐的等摩尔终点。加入二苯胺磺酸钠指示剂可继续滴定Fe(Ⅱ)而实现钛、铁连续测定。由于该氧化-还原体系中含有大量磷酸,因此在滴定钛(Ⅲ)时允行一定量的的钨、钒、锡存在,此法可用于钛矿物中钛铁联测以及钒钛磁铁矿和金红石中钛量的准确测定。2实验部分2.1主要试剂1.0g/LTiO2标准溶液(10%H2SO4介质);5.0g/LFe2O3。标准溶液(20%H… 相似文献
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金属-有机框架物在荧光识别领域表现出良好的应用前景,为探究合成更为精确识别的物质,本文利用二羧酸配体(H_2PAIA=5-丙酰胺基间苯二甲酸)和硝酸铜通过溶剂调控合成了两例结构不同的铜基金属-有机框架物(MOFs){[Cu(PAIA)(H_2O)]·2H_2O}(1)和{[Cu_3(PAIA)_2(DMSO)(Pyridine)_(1.5)]}(DMSO:二甲基亚砜;Pyridine:吡啶)(2)。尽管由相同的金属离子和有机配体构筑而成,但显示出具有显著溶剂导向特征的不同框架结构:配合物1为三维NbO型拓扑结构,而配合物2为二维sql型拓扑结构。正是由于这些结构上的差异,导致两个配合物的荧光识别性能和疏水性能展现出显著的不同。配合物1能够同时识别Pb~(2+)和Ag~+离子,而配合物2只能识别Pb~(2+),对Ag~+没有明显的信号响应。配合物1的疏水角85.06°比配合物2的52.71°有显著的增加。 相似文献
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A sensitive correlation between the ground-state properties of light kaonic nuclei and the symmetry energy at high densities is constructed under the framework of relativistic mean-field theory. Taking oxygen isotopes as an example, we see that a high-density core is produced in kaonic oxygen nuclei, due to the strongly attractive antikaonnucleon interaction. It is found that the 1 S_(1/2) state energy in the high-density core of kaonic nuclei can directly probe the variation of the symmetry energy at supranormal nuclear density, and a sensitive correlation between the neutron skin thickness and the symmetry energy at supranormal density is established directly. Meanwhile, the sensitivity of the neutron skin thickness to the low-density slope of the symmetry energy is greatly increased in the corresponding kaonic nuclei. These sensitive relationships are established upon the fact that the isovector potential in the central region of kaonic nuclei becomes very sensitive to the variation of the symmetry energy. These findings might provide another perspective to constrain high-density symmetry energy, and await experimental verification in the future. 相似文献
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A novel 1 kHz single-frequency, Q-switched Er-doped yttrium aluminum garnet(Er:YAG) laser pumped by a 1470 nm laser diode is demonstrated. The 500 ns, 5.52 mJ single-frequency, diffraction-limited pulses are obtained by using a ‘ramp-fire' injection-seeding technique and an optical feedback architecture. The full width at half-maximum of the pulse spectrum is measured to be 1.47 MHz by using the heterodyne technique. The beam quality M2 factors are measured to be 1.18 and 1.24 in the x and y directions, respectively. 相似文献