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81.
A novel type of Ti decorating benzene grafted tetrahydrido-silsequioxane struc-tures was designed and investigated using density functional theory(DFT).The hydrogen adsorption properties of this new material were investigated at the same level of theory.The results reveal that up to four hydrogen molecules(with the restrict of 18 electrons rule) can be adsorbed on each Ti atom of(TiC6H5)m-H4-mSi4O6(m = 1-4) molecular systems with the average binding energies of 0.691,0.692,0.693 and 0.695 eV for m = 1-4,respectively.The variations of HOMO- LUMO energy gaps verify that the host structures with four H2 molecules adsorbed own the best kinetics stability.The interaction mechanism of H2 molecules with the host materials mainly attributes to the well-known "kubas interactions".All the results indicate that the complex structures designed here may be used as hydrogen storage materials at ambient conditions. 相似文献
82.
On the basis of deterministic fractals and the Rotne-Prager hydrodynamic interaction tensor, we confirm the asymptotic as well as the finite size scaling of the friction coefficient lambda of a self-similar structure. The fractal assembly is made of N spheres with its dimension varying from D < 1 to D = 3. The number of spheres can be as high as N approximately O(10(4)). The asymptotic scaling behavior of the friction coefficient per sphere is lambda approximately N(1/D-1) for D > 1, lambda approximately (lnN)(-1) for D = 1, and lambda approximately N(0) for D < 1. The crossover behavior indicates that while in the regime of D > 1 the hydrodynamic screening effect grows with the size, for D<1 it is limited in a finite range, which decays with decreasing D. 相似文献
83.
Tsao George T. Xia Liming Cao Ningjun Gong Cheng S. 《Applied biochemistry and biotechnology》2000,84(1-9):743-749
Aspergillus niger NRRL3 was cultivated in a moist wheat bran and ground corncob solid medium supplemented with inorganic minerals for the production
of cellobiase (β-1,4-glucosidase, EC 3.2.1.21). With this method, A. niger NRRL3 was able to produce a high concentration of cellobiase (215 IU/gofsolid substrate) after 96 h of incubation. Temperature
and moisture content affected final cellobiase titers. The best conditions for cell obiase production from solid substrate
by A. niger NRRL3 were determined to be 70% moisture and 35°C. 相似文献
84.
Design of quantum VQ iteration and quantum VQ encoding algorithm taking O(√N) steps for data compression
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Vector quantization (VQ) is an important data compression
method. The key of the encoding of VQ is to find the closest vector among
N vectors for a feature vector. Many classical linear search algorithms
take $O(N)$ steps of distance computing between two vectors. The quantum VQ iteration and corresponding quantum VQ encoding algorithm that takes
$O(\sqrt N )$ steps are presented in this paper. The unitary operation of
distance computing can be performed on a number of vectors simultaneously
because the quantum state exists in a superposition of states. The quantum VQ iteration comprises three oracles, by contrast many quantum algorithms have only one oracle, such as Shor's factorization algorithm and Grover's algorithm. Entanglement state is generated and used, by contrast the state in Grover's algorithm is not an entanglement state. The quantum VQ iteration is a rotation over subspace, by contrast the Grover iteration is a rotation over global space. The quantum VQ iteration extends the Grover iteration to the more complex search that requires more oracles. The method of the quantum VQ iteration is universal. 相似文献
85.
86.
PS胶体粒子表面逐层自组装固定化SOD及其生物活性 总被引:3,自引:0,他引:3
通过逐层自组装技术成功地把超氧化物歧化酶(SOD)吸附在聚苯乙烯(PS)胶体粒子表面.zeta电位和TEM证明了聚阳离子或聚阴离子型SOD与相反电荷的聚电解质在PS胶体粒子表面的交替吸附.通过测定SOD被胶体粒子吸附后上清液的生物活性,得到聚阴离子型SOD(pH=8.0)和聚阳离子型SOD(pH=4.3)在PS胶体粒子表面的吸附量分别为12和51IU,相对活性分别为23.4%和2.9%.聚阴离子型SOD在PS胶体粒子表面能形成平滑规整的膜,导致较高的相对活性.研究结果表明,通过调节pH值,可以优化自组装固定化酶的聚集状态和生物活性 相似文献
87.
ZHAO Chong YE Wang-Gui LI Ying-Kui SHEN Xiao-Fei CAO Zhi-Jun CAO Zhi-Quan WEN Zi-Cheng YUAN Xuan-Yi MA Chao-Yang CAO Yong-Ge 《结构化学》2021,(7):892-900
Pure phase Y_3Fe_5O_(12) (YIG) ceramic was successfully produced by tape-casting forming process and one-step solid-state sintering method.The activation energy for densification was calculated to be 183.81 kJ/mol.Pure YIG ceramic with a relative density as high as 99.8%was fabricated.The existence of O vacancy and Fe~(2+)ions was determined by XPS and EPR spectra.The RT saturation magnetization was measured to be 28.2 emu/g,and the hysteresis loss was calculated to be smaller than 10 mJ/kg in the temperature range of 230~360 K and be as high as238.8 mJ/kg at 30 K.The dielectric loss tangent tan was nearly zero at 6~7 GHz and 11~12 GHz.For complex permeability in the frequency range of 5~18 GHz,the magnetic loss tangent tan fluctuated at around zero.Therefore,the low values of tan and tan indicate that it is a low loss ceramic material. 相似文献
88.
89.
The photoluminescence of K4UO2(CO3)3 has been studied under conditions of high resolution at cryogenic temperatures. The origin corresponding to the pure electronic transition was located at 4774 Å (20945 cm-1), and it was found that the totally symmetric uranyl stretching mode was coupled to this transition. A progression of four band systems thus resulted, and from an examination of the energies of corresponding peaks in each system, a value of 813 cm-1 for the U-O stretching mode was determined. Two lattice modes (34 and 80 cm-1) and two molecular vibrational modes (205 and 276 cm-1) were also found to couple with the pure electronic transition, thus yielding approximately 15 major peaks in each band system. The 205 cm-1 vibration corresponded to a CO2-3 vibration, while the 276 cm-1 vibration was a UO2+2 deformation. The low values obtained for the force constant and totally symmetric stretching frequency of the U-O bond suggested that in UO2(CO)4-3, the uranium atom is bound in a complex species that may be considered as an intermediate between that of a uranyl (UO2+2) and a uranate (UO10-8) ion. 相似文献
90.
Homologues of pseudobaptigenin containing ethyl and propyl groups in position 2 have been synthesized. The structures of the new compounds have been comfirmed by PMR. 相似文献