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排序方式: 共有177条查询结果,搜索用时 15 毫秒
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QijianZhang DehuaHe QimingZhu 《天然气化学杂志》2003,12(2):81-89
The direct conversion of methane to methanol has attracted a great deal of attention for nearly a century since it was first found possible in 1902, and it is still a challenging task. This review article describes recent advancements in the direct partial oxidation of methane to methanol. The history of direct oxidation of methane and the difficulties encountered in the partial oxidation of methane to methanol are briefly summarized. Recently reported developments in gas-phase homogeneous oxidation, heterogeneous catalytic oxidation and liquid phase homogeneous catalytic oxidation of methane axe reviewed. 相似文献
3.
Electronic structure properties including bond lengths, bond angles, dipole moments (μ), energies, band gaps, NMR parameters of the isotropic and anisotropic chemical shielding parameters for the sites of various atoms were calculated using the density functional theory for Si, Ge, Sn, Pb doped (6,3) Chiral single-walled carbon nanotubes (SWCNTs). The calculations indicated that average bond lengths were as: Pb3C>Sn3C>Ge3C>Si3C>C3C. The dipole moments for Si, Ge, Sn, Pb doped (6,3) Chiral single-walled carbon nanotubes structures show fairly large changes with respect to the pristine model. 相似文献
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The inhibitory effects of four organic acids (OAs) in Radix Isatidis, a traditional Chinese medicinal herb, on Escherichia coli (E. coli) growth were investigated by microcalorimetry. The power‐time curves of E. coli growth with and without OAs were acquired, meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by growth rate constants (k1, k2), half inhibitory ratio (IC50), maximum heat output (Pmax) and peak time (tp). The values of k1 and k2 of E. coli growth in the presence of the four OAs decreased with the increasing concentrations of OAs. Moreover, Pmax was reduced and the value of tp increased with increasing concentrations of the four drugs. The sequence of anti‐microbial activity of the four OAs was: syringic acid>2‐amino‐benzoic acid>salicylic acid>benzoic acid. IC50 of the four OAs was respectively 56 µg/mL for syringic acid, 75 µg/mL for 2‐amino‐benzoic acid, 86 µg/mL for salicylic acid and 224 µg/mL for benzoic acid. The existence of the functional groups on phenyl ring improves the anti‐microbial activity compared to benzoic acid. The functional groups methoxyl at C(3) and C(5) improve anti‐microbial activity more strongly than the other functional groups, and the functional group amino at C(2) improve anti‐microbial activity more strongly than hydroxyl at C(2) on phenyl ring. 相似文献
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MA Ming-xiao JIN Ning-yi LIU Hui-juan ZHENG Mini YIN Ge-fen TIAN Ming-yao JIN Ming-lan LU Hui-jun SHEN Guo-shun ZHU Guang-ze JIN Hong-tao JIN Kuo-shi ZHANG Ying-jiu 《高等学校化学研究》2008,24(1):69-74
This article reports the design and construction of a multiple-epitope foot and mouth disease virus (FMDV) antigen, designated as OAAT. This recombinant antigen consists of the structural protein VP1 genes from serotypes A and O FMDV, five major VP1 immunodominant epitopes from two genotypes of Asial serotype, and three Th2 epitopes originating from the nonstructural protein, three ABC gene and structural protein VP4 gene. Expressions of target gene from these plasmids in HeLa cells were verified by Western-blot. BALB/c mice were immunized intramuscularly with the DNA vaccines thrice every two weeks. We found that pA could induce simultaneously specific antibodies against serotypes A, Asial, and O FMDV. Compared to those of the controls, the spots of FMDV-specific IFN-7 and cytotoxic activity from mice immunized with pA were significantly increased, pA provided full protection in 2/4 guinea pigs from challenge with FMDV O/NY00 and Asial/YNBS/58, respectively. The results show that although pA did not give full protection in 100% immunized guinea pigs from challenge with type O and Asial FMDV, respectively, OAAT may be potential immunogen against FMDV and pA may be potential DNA vaccines against FMDV. 相似文献
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Microfluidic technology has great advantages in the precise manipulation of micro and nano particles, and the separation of micro and nano particles based on ultrasonic standing waves has attracted much attention for its high efficiency and simplicity of structure. This paper proposes a device that uses three modes of ultrasonic standing waves to continuously separate particles with positive acoustic contrast factor in microfluidics. Three modes of acoustic standing waves are used simultaneously in different parts of the microchannel. According to the different acoustic radiation force received by the particles, the particles are finally separated to the pressure node lines on both sides and the center of the microchannel. In this separation method, initial hydrodynamic focusing and satisfying various equilibrium constraints during the separation process are the key. Through numerical simulation, the resonance frequency of the interdigital transducer, the distribution of sound pressure in the liquid, and the relationship between the interdigital electrode voltage and the output sound pressure are obtained. Finally, the entire separation process in the microchannel was simulated, and the separation of the two particles was successfully achieved. This work has laid a certain theoretical foundation for the rapid diagnosis of diseases in practical applications. 相似文献
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TANG Ke HONG Xin ZHAO YongHua SONG LiJuan & SUN ZhaoLin School of Material Chemical Engineering Liaoning Institute of Technology Jinzhou China College of Petrochemical Engineering Liaoning University of Petroleum & Chemical Technology Fushun 《中国科学:化学》2010,(1)
Gallium atoms have been introduced into the framework of Y zeolite by treating the zeolite with an aqueous solution of ammonium hexafluoro gallate.Desulfurization of various model fuels containing about 500 μg/g sulfur has been studied over the synthesized Y zeolite(GaAlY).The sulfur adsorption capacity is 7.0,17.4,14.5,16.9,6.9 and 5.8 mg(S)/g adsorbent for thiophene,tetrahydrothiophene(THT),4,6-dimethyldibenzothiophene(4,6-DMDBT),dibenzophiophene(DBT),benzothiophene(BT) and 4-methyldibenzothiophene(4-MDBT... 相似文献
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A graph G is called quasi-claw-free if it satisfies the property:d(x,y)=2 there exists a vertex u∈N(x)∩N(y)such that N[u]■N[x]∪N[y].In this paper,we show that every 2-connected quasi-claw-free graph of order n with G■F contains a cycle of length at least min{3δ+2,n},where F is a family of graphs. 相似文献
10.
用固体石蜡山梨酸碳糊电极电位法测定食品中山梨酸 总被引:1,自引:0,他引:1
制备了一种以山梨酸根与乙基紫形成的缔合物为电活性物的固体石蜡山梨酸碳糊电极,并对其性能做了测定。结果显示该电极对山梨酸有较好的能斯特响应。山梨酸的线性范围为2.2×10-5~1.0×10-1mol.L-1,检出限为1.6×10-5mol.L-1。该电极用于食品中山梨酸根的测定,结果与分光光度法结果相符。 相似文献