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971.
薛具奎  段文山  郎和 《中国物理》2002,11(11):1184-1187
Using the standard reductive perturbation technique,a nonlinear Schroedinger equation is derived to study the modulational instability of finite-amplitude ion-acoustic waves in a non-magnetized warm plasma.It is found that the inclusion of ion temperature in the equation modifies the nature of the ion-acoustic wave stability and the soliton stuctures.The effects of ion plasma temperature on the modulational stability and ion-acoustic wave properties are inestigated in detail.  相似文献   
972.
The title complex, [CuCl2(C6H6N4S2)], has a flattened tetrahedral coordination. The CuII atom is located on a twofold rotation axis and is coordinated by two N atoms from a chelating 2,2′‐di­amino‐4,4′‐bi‐1,3‐thia­zole ligand and by two Cl atoms. Intramolecular hydrogen bonding exists between the amino groups of the 2,2′‐di­amino‐4,4′‐bi‐1,3‐thia­zole ligand and the Cl atoms. The intermolecular separation of 3.425 (1) Å between parallel bi­thia­zole rings suggests there is a π–π interaction between them.  相似文献   
973.
六味地黄丸的精细指纹图谱分析及模式识别分类研究   总被引:6,自引:0,他引:6  
采用高效液相色谱建立了六味地黄丸的指纹图谱,对两个厂家的16批产品进行了测定,并结合中药相似度软件和主成分分析法对全指纹图谱和其精细指纹图谱进行了模式识别研究。结果表明,中药相似度软件能够对不同厂家的产品进行区分但也可能造成误判;在主成分分析法的投影图中,两个厂家的产品明显聚为两类,而且不同批次产品的差异也能够显示出来。  相似文献   
974.
综述了近年来国内外酶固定化载体的研究进展,侧重于无机材料和有机聚合物材料上的固定化酶方法;此外,也介绍了固定化胰蛋白酶反应器与分离系统联用在蛋白质样品分析中的应用,并展望了固定化酶反应器的研究方向及其在蛋白质组中的应用前景。  相似文献   
975.
Elastic scattering of 10Be on a 208Pb target was measured at ELab=127 MeV,which corresponds to three times the Coulomb barrier.The secondary 10Be beam was produced at the Radioactive Ion Beam Line in Lanzhou of the Heavy-Ion Research Facility in Lanzhou.The angular distribution of elastic scattering in the 10 Be+208Pb system shows a typical Fresnel diffraction peak.Optical model analysis of the angular distribution was performed using the Woods-Saxon,double-folding and global potentials.With the global potential,different density distributions were used.The results indicate that different density distributions for the projectile induce distinct effects in the angular distribution.  相似文献   
976.
Safflower has both medicinal and edible values but research on its nutrient composition is still lacking. This study was established for the quantitative determination of 28 nucleosides, nucleobases, and amino acids based on the ultra‐performance liquid chromatography coupled with triple‐quadrupole linear ion‐trap tandem mass spectrometry. Analysis of 30 batches of safflower from different producing areas indicated that the contents of l ‐proline, l ‐asparagine, l (+)‐arginine, l ‐serine, l ‐histidine, uracil, guanosine, and uridine was high in safflower. Principle component analysis and cluster analysis found that samples from different regions could be distinguished well, and samples from the same area could be clustered into one class, different geographical environments may cause the differences of nucleosides, nucleobases, and amino acids in safflower. The analysis of principal component analysis, cluster analysis, and counter propagation artificial neural network show similar results. Then the content of nucleosides, nucleobases, and essential amino acids were compared, and found that the content in safflower from Gansu was higher than those from other regions, and there was a little difference between the samples from Xinjiang, Sichuan, and Yunnan. This research revealed the composition of nucleosides, nucleobases, and amino acids in safflower, and provided a theoretical basis for utilization of safflower.  相似文献   
977.
Prostate-specific membrane antigen (PSMA) is a well-established biological target that is overexpressed on the surface of prostate cancer lesions. Radionuclide-labeled small-molecule PSMA inhibitors have been shown to be promising PSMA-specific agents for the diagnosis and therapy of prostate cancer. In this study, a glutamate-urea-based PSMA-targeted ligand containing an isonitrile (CNGU) was synthesized and labeled with 99mTc to prepare [99mTc]Tc-CNGU with a high radiochemical purity (RCP). The CNGU ligand showed a high affinity toward PSMA (Ki value is 8.79 nM) in LNCaP cells. The [99mTc]Tc-CNGU exhibited a good stability in vitro and hydrophilicity (log P = −1.97 ± 0.03). In biodistribution studies, BALB/c nude mice bearing LNCaP xenografts showed that the complex had a high tumor uptake with 4.86 ± 1.19% ID/g, which decreased to 1.74 ± 0.90% ID/g after a pre-injection of the selective PSMA inhibitor ZJ-43, suggesting that it was a PSMA-specific agent. Micro-SPECT imaging demonstrated that the [99mTc]Tc-CNGU had a tumor uptake and that the uptake was reduced in the image after blocking with ZJ-43, further confirming its PSMA specificity. All of the results in this work indicated that [99mTc]Tc-CNGU is a promising PSMA-specific tracer for the imaging of prostate cancer.  相似文献   
978.
Atomic regulation of metal catalysts has emerged as an intriguing yet challenging strategy to boost product selectivity. Here, we report a density functional theory-guided atomic design strategy for the fabrication of a NiGa intermetallic catalyst with completely isolated Ni sites to optimize acetylene semi-hydrogenation processes. Such Ni sites show not only preferential acetylene π-adsorption, but also enhanced ethylene desorption. The characteristics of the Ni sites are confirmed by multiple characterization techniques, including aberration-corrected high-resolution scanning transmission electron microscopy and X-ray absorption spectrometry measurements. The superior performance is also confirmed experimentally against a Ni5Ga3 intermetallic catalyst with partially isolated Ni sites and against a Ni catalyst with multi-atomic ensemble Ni sites. Accordingly, the NiGa intermetallic catalyst with the completely isolated Ni sites shows significantly enhanced selectivity to ethylene and suppressed coke formation.  相似文献   
979.
Zhang  Bo  Wang  Haiying  Yan  Xuechao  Duan  Yu-Ai  Guo  Shuai  Luo  Fei-Xian 《Transition Metal Chemistry》2020,45(2):99-110
Transition Metal Chemistry - A series of ruthenium [NNN]- or [NCN]-type complexes (3–7) bearing PPh3 ancillary ligands have been synthesized from pyridine- or phenylene-bridged bis(triazoles)...  相似文献   
980.
Cheng  Zheng  Li  Jinpeng  Wang  Bin  Zeng  Jinsong  Xu  Jun  Zhu  Shiyun  Duan  Chengliang  Chen  Kefu 《Cellulose (London, England)》2022,29(13):7083-7098
Cellulose - Nanocellulose, a unique and promising nanosized cellulose fibers extracted from renewable biomass, has gained much attention from both the scientific and industrial communities due to...  相似文献   
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