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991.
Rational construction of 3D pillared metal-organic frameworks: synthesis, structures, and hydrogen adsorption properties 总被引:1,自引:0,他引:1
In our efforts toward rational design and systematic synthesis of 'pillar-layer' structure MOFs, three porous MOFs have been constructed based on [Zn(4)(bpta)(2)(H(2)O)(2)] (H(4)bpta = 1,1'-biphenyl-2,2',6,6'-tetracarboxylic acid) layers and three different bipyridine pillar ligands. The resulted MOFs show similar structures but different pore volume and window size depending on the length of pillar ligands which resulted in distinct gas adsorption properties. In the three MOFs, [Zn(4)(bpta)(2)(4,4'-bipy)(2)(H(2)O)(2)]·(DMF)(3)·H(2)O (1) (DMF = N,N'-dimethylformamide and 4,4'-bipy = 4,4'-bipyridine) reveals selective adsorption of H(2) over N(2) and O(2) as the result of narrow pore size. [Zn(4)(bpta)(2)(azpy)(2)(H(2)O)(2)]·(DMF)(4)·(H(2)O)(3) (2) and [Zn(4)(bpta)(2)(dipytz)(2)(H(2)O)(2)]·(DMF)(4)·H(2)O (3) (azpy =4,4'-azopyridine, dipytz = di-3,6-(4-pyridyl)-1,2,4,5-tetrazine) reveal pore structure change upon different activation conditions. In addition, the samples activated under different conditions show distinct adsorption behaviors of N(2) and O(2) gases. Furthermore, hydrogen adsorption properties of activated 1-3 were studied. The results indicated that the activation process could affect the hydrogen enthalpy of adsorption. 相似文献
992.
993.
为了研究飞秒激光诱导水光学击穿阈值随激光脉冲参数的变化关系,采用四阶RungeKutta方法对飞秒激光诱导水光学击穿的椭球体模型进行了不同脉宽(40~540fs)、波长(400~1200nm)和光斑尺寸(0~200μm)下的数值模拟。通过控制变量法得出阈值光强与这些激光脉冲参数的关系曲线图,据此定性分析了阈值光强与激光脉冲参数的变化特征趋势。应用光强与功率、能量、辐照曝光量和电场强度之间的关系,得到了它们随激光脉冲参数脉宽、波长和光斑尺寸的动态关系,这为进一步研究飞秒激光与水和含水介质的相互作用提供了理论依据。 相似文献
994.
995.
In this paper,we give further results on the Drazin inverse of tensors via the Einstein product.We give a limit formula for the Drazin inverse of tensors.By using this formula,the representations for the Drazin inverse of several block tensor are obtained.Further,we give the Drazin inverse of the sum of two tensors based on the representation for the Drazin inverse of a block tensor. 相似文献
996.
An LD-pumped Nd:YVO4 passively Q-switched by V:YAG and intracavity frequency doubled by LBO red pulse laser at 671 nm was presented. With 1.6 W incident pump power, average output power of 53 mW, pulse duration (FWHM) of 29.5 ns, pulse repetition rate of 37.2 kHz, peak power of 48.3 W and single-pulse energy of 1.43 μJ were obtained. The stability of pulse energy and repetition rate was better than 3% for 4 h. 相似文献
997.
Zhigao Huang Shangdong Li Haishan Lin Fengming Zhang Youwei Du 《Journal of magnetism and magnetic materials》2006
The exchange bias (HE) and coercivity (HC) of the ferromagnet/antiferromagnet (FM/AFM) films have been simulated with Monte Carlo method. The simulated results indicate that, the value of HE decreases with increasing temperature, and the values of HE and the blocking temperature Tb at which HE=0 reduce evidently with decreasing absolute value of interlayer exchange coupling JI. It also is found that for the large absolute values of JI, the maximum in HC occurs very close to Tb. At the same time, it is observed that the diluted ratio of FM at FM/AFM interface influences clearly the value of HE. The simulated results are consistent with the experimental facts. The maximum behaviour in the HC−T curves has been explained by the interplay of the softening of some fraction of the spins in the AFM layer near TN′ and the disorder of the spins in FM layer near Curie temperature TC. 相似文献
998.
研究了具有多时滞线性切换系统的稳定性及其反馈镇定问题,利用完备性条件、矩阵分解与二次Lyapunov泛函,给出了多时滞切换系统渐近稳定的充分条件和切换律设计方法.在此基础上,研究了这类系统的镇定控制问题,设计了保证系统时滞独立渐近镇定的控制器. 相似文献
999.
Xia Meng Xingjian Wang Hongdong Duan Juan Bu Dawei Qin Yi Zhang 《Research on Chemical Intermediates》2013,39(8):3829-3833
In this work, two novel indole–hydrazone analogues were prepared by condensation reactions between 5-methoxyindole-3-carboxaldehyde and isobutyric acid hydrazide or hydrazine hydrate, respectively. The structural properties of the synthetic products were confirmed by FT-IR, 1H NMR, and elemental analysis, while the thermal stabilities and purities were measured by melting point determination. The inhibition effect of compounds was predicted by quantum treatment. The results showed that these compounds can be used as inhibitors. 相似文献
1000.
卜小明 《应用数学和力学(英文版)》1993,14(9):859-866
In this paper,the theorems concerning the summation of Fourier series withparameter are given by using the Laplace transforms.By means of the known result ofLaplace transforms,many new,important problems of summation of Fourier serieswith parameter in mechanics can be solved. 相似文献