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901.
902.
Yuanzheng Yue 《Journal of Non》2009,355(10-12):737-744
This paper describes how the fragility of a liquid is linked to the ratio between the energy barrier (Eeq) for the equilibrium viscous behavior and that (Eiso) for the non-equilibrium iso-structural viscous behavior. Using the concept of iso-structural viscosity, two functions describing the variation of the configurational entropy (Sc) with temperature (T) are obtained from the Avramov-Milchev (AM) and the Vogel-Fulcher-Tammann (VFT) viscosity equations, respectively. The two Sc(T) functions exhibit different relations to the liquid fragility. The AM Sc(T) function is a power function with the exponent of F ? 1, where F is the AM fragility index. In this case, Sc vanishes at T = 0 K. For the VFT function, Sc vanishes as T is lowered to a finite temperature T0, whereas it reaches the maximum value Sc,max at infinitively high T. Sc,max is proportional to the VFT fragility index. Thus, the VFT equation is not only a dynamical, but also a thermodynamic model. It is proved that for oxide liquids, the VFT equation describes viscosity data better than the AM equation, provided the pre-exponential factor η0 is fixed to a generally accepted value, e.g., 10?3.5 Pa s. 相似文献
903.
904.
Two alkane dicarboxylates substituted titanium-oxo-clusters, Ti6O3(OOCCH2COO)2(O i Pr)14 (1) and Ti6O3(OOCC2H4COO)2(O i Pr)14 (2), were successfully prepared by one step in situ solvothermal synthesis. The compounds are the first examples of only flexible alkane dicarboxylate-substituted titanium-oxo-clusters. The structures of the compounds are best described as two trinuclear oxo-Ti3 subunits linked by a μ 2-O bridge and two malonate or succinate ligands, forming Ti6 clusters. A photochromic effect was observed upon irradiating the crystals, and the color of the crystals was changed from transparent to gray. Photodegradation of the methyl orange in aqueous dispersions of microcrystals of compounds 1 and 2 were carried out under UV cut white light with the assistance of H2O2. Compound 2 exhibited higher photocatalytic activity than 1, which might be related to the smaller angles of μ 2-O bridge in 2. 相似文献
905.
Jiming Wang Chao Feng Cheng Min Ge Shuhua Zhang Hong Hai 《Journal of Cluster Science》2016,27(6):2001-2011
Two tetranuclear complexes, [M(H3L)]4·X (1, M = Cu, X = 4,4′-dpdo; 2, M = Ni, X = DMF, H5L = 2-[(3,5-dibromo-2-hydroxybenzyl) amino]-2-(hydroxymethyl)propane-1,3-diol, 4,4′-dpdo is 4,4′-bipyridine-N,N′-dioxide, DMF = N,N′-dimethyl formamide), have been synthesized and characterized by elemental analysis, IR and X-ray single-crystal diffraction. Compound 1 features a centrosymmetric tetranuclear copper cluster which further constructed a 1D chain through a tetra-acceptor hydrogen bonds of 4,4′-dpdo molecule. Compound 2 having a P21 /n space group also exhibits a tetranuclear nickel cluster with a cubane topology in which the central Ni(II) ion and oxygen atoms from H3L2? occupy the alternate vertices of the cube. Magnetic properties of 1 and 2 in the 2–300 K have also been discussed. The tetranuclear cubanes cores display dominant ferromagnetic interactions. 相似文献
906.
无色散p-约化KP系列是无色散KP系列的约化形式.基于两个形式劳伦级数,由特殊的附加对称流,无色散p-约化KP系列的弦方程被给出. 相似文献
907.
Zhang Qun Ge Kun Duan Jianlei Chen Shizhu Zhang Ran Zhang Cuimiao Wang Shuxiang Zhang Jinchao 《Journal of nanoparticle research》2014,16(11):1-12
The sintering of a silver (Ag) nanoparticle film by laser beam irradiation was studied using a CW DPSS laser. The laser sintering of the Ag nanoparticle thin film gave a transparent conductive film with a thickness of ca. 10 nm, whereas a thin film sintered by conventional heat treatment using an electronic furnace was an insulator because of the formation of isolated silver grains during the slow heating process. The laser sintering of the Ag nanoparticle thin film gave a unique conductive network structure due to the rapid heating and quenching process caused by laser beam scanning. The influences of the laser sintering conditions such as laser scan speed on the conductivity and the transparency were studied. With the increase of scan speed from 0.50 to 5.00 mm/s, the surface resistivity remarkably decreased from 4.45 × 108 to 6.30 Ω/sq. The addition of copper (Cu) nanoparticles to silver thin film was also studied to improve the homogeneity of the film and the conductivity due to the interaction between the oxidized surface of Cu nanoparticle and a glass substrate. By adding 5 wt% Cu nanoparticles to the Ag thin film, the surface resistivity improved to 2.40 Ω/sq. 相似文献
908.
Xiaodong Hu Weike Wang Qiang Hu Xing Lei Qing Wei Yuanzheng Liu Jiliang Wang 《中国光学快报(英文版)》2014,12(7):72901-78
The stray radiation suppression in Cassegrain family optical system is presented. The design method for ultra-short outer baffle with honeycomb structure is proposed. Meanwhile the constraint formulas for designing the geometries of primary baffle and secondary baffle are deduced when basing the characteristic and taking vignette into account. According to the ray trace simulated data, the point source transmit- tance values of the baffle are less than 10-^10 when incident angles are larger than the rejection angle. The honeycomb-look front baffle guarantees a comparable performance of stray light suppression with traditional tube baffle, while reducing the size greatly. 相似文献
909.
LIU Ge LU YuanRong YIN XueJun ZHANG XiaoHu DU Heng JIANG PeiYong LI ZhongShan LI XiaoNi HE Yuan WANG Zhi GAO ShuLi YANG YaQing ZHU Kun YAN XueQing CHEN JiaEr YUAN YouJin XIA JiaWen ZHAO HongWei 《中国科学:物理学 力学 天文学(英文版)》2014,57(7):1311-1317
The 53.667 MHz continuous-wave heavy ion RFQ has been designed and manufactured for the SSC-LINAC project.This four-rod RFQ accelerates ions with maximum mass to charge ratio of 7 from 3.728 keV/u to 143 keV/u.Measurements have been carried out to check the RF performance of the cavity and the quality of the electric field.The S11 of the power coupler is adjusted to better than-44 dB,and the Q0 of the cavity is 6440.The quality of the electric field is evaluated by the perturbation method.The measurement procedure and data analysis will be discussed in detail.The error due to gravity of the perturbation bead has been corrected by averaging the fields in different quadrants.As a result,the unflatness of the electric field is±2.5%,and the dipole field component distributes from 0%to 20%in different longitudinal positions,which indicates the asymmetry of the quadrupole field.The unflatness of the quadrupole field distribution represents a good agreement with the simulation results.High power RF test and beam commissioning of the RFQ are on schedule in early 2014. 相似文献
910.
Xinmin Ge Yiren Fan Yingchang Cao Yongjun Xu Xi Liu Yiguo Chen 《Applied magnetic resonance》2014,45(2):155-167
The carbonate reservoir has a number of properties such as multi-type pore space, strong heterogeneity, and complex pore structure, which make the classification of reservoir pore structure extremely difficult. According to nuclear magnetic resonance (NMR) T 2 spectrum characteristics of carbonate rock, an automatic pore structure classification and discrimination method based on the T 2 spectrum decomposition is proposed. The objective function is constructed based on the multi-variate Gaussian distribution properties of the NMR T 2 spectrum. The particle swarm optimization algorithm was used to solve the objective function and get the initial values and then the generalized reduced gradient algorithm was proposed for solving the objective function, which ensured the stability and convergence of the solution. Based on the featured parameters of the Gaussian function such as normalized weights, spectrum peaks and standard deviations, the combinatory spectrum parameters (by multiplying peak value and normalized weight for every peak) are constructed. According to the principle of fuzzy clustering, the carbonate rock pore structure is classified automatically and the discrimination function of each pore structure type is obtained using Fisher discrimination analysis. The classification results were analyzed with the corresponding casting thin section and scanning electron microscopy. The study shows that the type of the pore structure based on the NMR T 2 spectrum decomposition is strongly consistent with other methods, which provides a good basis for the quantitative characterization of the carbonate rock reservoir pore space and lays a foundation of the carbonate rock reservoir classification based on NMR logging. 相似文献