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131.
Wei‐Lie Xiao Jian‐Xin Pu Rui‐Rui Wang Liu‐Meng Yang Xiao‐Li Li Sheng‐Hong Li Rong‐Tao Li Sheng‐Xiong Huang Yong‐Tang Zheng Han‐Dong Sun 《Helvetica chimica acta》2007,90(8):1505-1513
Seven new highly oxygenated nortriterpenoids, rubriflorins D–J ( 1 – 7 ), were isolated from the leaves and stems of Schisandra rubriflora, and their structures were elucidated on the basis of extensive analysis of spectroscopic data. These new compounds feature the opening of ring A compared with related known nortriterpenoids isolated from the genus Schisandra and showed weak activity against HIV‐1. 相似文献
132.
Hyun-Joo Kim Seog-Tae Han Jeong-Geun Kim Tai-Seong Kim Kwang-Dong Kim Chang-Hoon Lee Moon-Hee Chung Yong-Gi Kim 《International Journal of Infrared and Millimeter Waves》2002,23(1):135-147
The frequency tuning range of waveguide oscillator and its stability depend sensitively on the dimension of the resonance cap. Therefore the driving-point impedances with the various dimensions of the resonance cap are calculated by using HFSS(High Frequency Simulation System). In this paper the comparisons between theoretical results of the driving-point impedances as a function of frequency and that of experimental results are described. The oscillation frequency range could be predicted by using the theoretical evaluation methods which are proposed. It shows that resonance cap size and disc height have an effect on the frequency tuning characteristics of Gunn oscillator. 相似文献
133.
X-ray absorption spectra of plasmas 总被引:1,自引:0,他引:1
In this paper we present a theoretical method to calculate the absorption spectra of hot dense plasmas. Based on our fully relativistic treatment incorporated with the quantum defect theory to handle the huge number of transition arrays from many configurations with high principal quantum number, we can calculate the absorption spectra for any element or multi-element plasmas with little computational efforts. We calculate the absorption spectra of C10H1605 plasmas, which are in good agreement with the experimental spectra. We can then provide diagnostic analysis for plasmas in relevant inertial confinement fusion (lCF) experiments; namely not only to determine plasmas' temperatures and densities, but also to provide the population densities of various ionic stages. Our theoretical method verified by "benchmark experiments" will be a basic tool to provide "precise" opacity data for the ICF research.`` 相似文献
134.
ThefascinatingsbocturesandpropertiesoffullereneshaveoPeneduPanewfieldofchendstry.Inparticular,F.Wudletal.l'2haveshownthatwatersofubleC6ocomPoundsinhibittheHITVen-zymesprotease(HIVP)andreversetranscriPtase(HIVRT).IthasbeenafocusofstUdytoinvestigatethebiologicalactivitiesofthesenovelsubstances.Fortheirpossiblemedicaluses,tolinkC6omoleculetonaturalProductssuchassugars,pephdes,amioacides,andsoonisanimPortantmethodinthisfield.Vasella3reportedthefirstglucosidederivativeofC6o'InthispaPer,w… 相似文献
135.
ICP-AES法测定富锗酵母中微量元素 总被引:2,自引:0,他引:2
本文采用美国LeemanLabs公司中阶梯光栅光谱仪测定了人工培养的富锗酵母中高含量锗及镁、铜、锌、铁、钾、钠等微量元素,研究了富锗样品的前处理方法,样品加标回收率在90%-103%之间,测量相对标准偏差:锗10%,镁、铜、锌、铁、钾、钠等元素小于7%。 相似文献
136.
137.
Manicka Dhanasekar Jianjun Han Qinghua Qin 《Finite Elements in Analysis and Design》2006,42(14-15):1314-1323
Much work on special elements that simplify geometrical modelling of structures containing holes, cracks and/ or inclusions has been reported extensively in the literature. This paper presents a hybrid-Trefftz element containing elliptic hole formulated using Hellinger–Reissner principle by employing trial functions based on the mapping technique and the Cauchy integral method. The element presented in this paper could be regarded as an improved formulation over Piltner [Special finite elements with holes and internal cracks, Int. J. Numer. Methods Eng. 21 (1985) 1471–1485] element because the chosen trail functions in this paper have provided relatively more stable solutions. The use of the element with other ordinary displacement-based finite elements has also yielded very accurate solutions even when very coarse meshes relative to the size of the elliptic hole have been used. 相似文献
138.
Herein, we report an efficient process for preparing monodisperse Au@SiO2 nanoparticles using homogeneous shaking and without the use of surface‐coupling silane agents or large stabilizers. The resulting pure‐silica surface of the Au@SiO2 nanoparticles is very important for straightforward surface functionalization with different functional groups via well‐established silica surface chemistry. Subsequent covalent bioconjugation of the aldehyde‐functionalized Au@SiO2 nanoparticles with various biomolecules is successfully employed to make robust nanoprobes for fast, colorimetric DNA and protein detection based on the sequence‐specific hybridization properties of DNA and the specific binding affinity between proteins, respectively. 相似文献
139.
Zhishen Mo Lixiao Wang Hongfang Zhang Ping Han Baotong Huang 《Journal of Polymer Science.Polymer Physics》1987,25(9):1829-1837
Wide-angle X-ray scattering from presumed block copolymers of polypropylene (PP) and ethylene-propylene copolymer (EPR), i.e., PP-EPR and PP-EPR-PP, synthesized by sequential polymerization with δ-TiCl3? Et2AlCl, was examined and compared with WAXS of mechanical blends and chain-transfer mixtures of PP and EPR with comparable compositions. The peak at 2θ = 20° for both the copolymers and the mixtures was attributed to the γ modification of PP in EPR. A strong variation in the ratio of diffraction intensities I040/I110 of PP in block copolymers and mixtures was explained in terms of crystallite growth in different directions. Analysis of the patterns and calculation of crystallinity, crystallite size, and lattice parameters led to the conclusion that block structure existed in the prepared copolymers. 相似文献
140.
Guilin Wen Qing-Guo Wang Chong Lin Xu Han Guangyao Li 《Chaos, solitons, and fractals》2006,29(5):1142-1146
Synchronization under output feedback control with multiple random time delays is studied, using the paradigm in nonlinear physics—Chua’s circuit. Compared with other synchronization control methods, output feedback control with multiple random delay is superior for a realistic synchronization application to secure communications. Sufficient condition for global stability of delay-dependent synchronization is established based on the LMI technique. Numerical simulations fully support the analytical approach, in spite of the random delays. 相似文献