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61.
62.
I.IntroductionThesoundfieldproducedbyanidealbaflledplanartransducerhasbeenoneofthemostfundamentalproblernsinacousticsforaverylongtime.TheproblemcanbereducedtothewellknownRayleighintegralorKing'sintegral.Inmostcases,however,theirsolutionsarenotanalyticalandcdnnotberepreselltedinclosedformbygeneralorspecialfunctions.AsanexaInPleoftheuniformpistonsource)todescribethesoundbeamdistributionsinthenearandtransitionzones,itisnecessarytomakecalculationsbyusingthenumericalintegrations(point-by-poillt)o… 相似文献
63.
In this paper we determine the necessary and sufficient conditions for the semidirect products and the wreath products of two monoids to be strongly -inverse. Furthermore, we determine the least group congruence on a strongly -inverse monoid, and we give some important isomorphism theorems. 相似文献
64.
Molybdosphoric Acid Mixed with Titania Used as a Catalyst to Synthesize Diphenyl Carbonate via Transesterification of Dimethyl Carbonate and Phenol 下载免费PDF全文
Tong Chen Huajun Han Zhiping Du Jie Yao Gongying Wang Dachuan Shi Desheng Zhang Zhiming Chen 《天然气化学杂志》2006,15(4):303-306
The 12-molybdosphoric acid mixed with titania (MPA-TiO2) was found to be a novel and efficient catalyst for the synthesis of diphenyl carbonate (DPC) via transesterification of dimethyl carbonate (DMC) and phenol. The X-ray diffraction (XRD) and infrared (IR) techniques were employed to characterize the prepared catalysts. The effect of the weight ratio of the 12-molybdosphoric acid to titania on the transesterification was investigated. A 13.1% yield of DPC and an 11.6% yield of methyl phenyl carbonate (MPC) were obtained over MPA-TiO2 with the weight ratio of MPA to TiO2 as 5:1. 相似文献
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66.
Desheng Liu Juan Du Guo-Qiang Huang 《International Journal of Theoretical Physics》2012,51(7):2113-2118
We investigate the quantum Fisher information in the symmetric pure three-qubit state. It is shown that the quantum Fisher information and the mean spin direction are determined by the probability amplitudes and the relative phase of the symmetric pure three-qubit state; while the length of mean spin is only determined by the probability amplitudes. 相似文献
67.
建立分光光度法分析眼科植入物人工晶体中清洗剂磺基琥珀酸二辛酯钠残留的方法。磺基琥珀酸二辛酯在酸性水溶液介质中与亚甲基蓝形成离子对,用三氯甲烷提取并在651 nm波长处测定其吸光度。磺基琥珀酸二辛酯钠的质量浓度在1.0~5.0μg/m L内与吸光度呈良好的线性关系,线性相关系数r~2=0.990 1,检出限为0.4μg/m L。测定结果的相对标准偏差为1.21%(n=6),日间重复性为2.06%(n=6);加标回收率为90%~97%。该方法检出限低,再现性好,适用于人工晶状体中磺基琥珀酸二辛酯钠残留量的测定。 相似文献
68.
Xiao Lin Zhuojun Wang Guilan Sun Lan Shen Desheng Xu Yi Feng 《Biomedical chromatography : BMC》2010,24(8):820-825
Interest in antimyocardial ischemic activity of a graminan‐type fructan with a weight average molecular weight of 4.8 kDa extracted from Radix Ophiopogonis (ROP) has necessitated the study of its pharmacokinetics and tissue distribution. For that, a simple HPGPC–FD method was developed for the sensitive and specific determination of FITC‐ROP (fluorescein–isothiocyanate‐labeled ROP) in plasma and rat tissues (heart, liver, spleen, lung, kidney, brain and stomach). The analyte was separated on a Shodex Sugar KS‐802 high‐performance gel column with 0.1 M phosphate buffer (pH 7.0) as mobile phase at a flow rate of 0.5 mL/min, and fluorescence detection at λex 495 nm and λem 515 nm. The calibration curve for FITC‐ROP was linear over the range 0.25–20.0 or 50.0 μg/mL in all studied biosamples with correlation coefficients >0.995. The inter‐day and intra‐day precisions of analysis were not more than 10%, and assay accuracy ranged from 93 to 105% for plasma and from 89 to 108% for tissue homogenates. This method has been confirmed here to be suitable for the study of pharmacokinetics and tissue distribution of ROP and the achieved results are highly instructive for the further pharmaceutical development of ROP, suggesting the promising application of the method to the increasingly important carbohydrate‐based drugs. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
69.
A variational phase field model is proposed for curve smoothing, in which a weight function is associated with the similarity measure term in the model so that important geometric features could be well preserved. Finite element approximation of the proposed model is given for its numerical implementation. Since the model has a linear weak variational form, the discretized system could be solved efficiently by many existing solution techniques. An effective algorithm is also developed, for the purpose of feature preservation, to automatically determine the weight from the given data. Various numerical examples are presented to demonstrate effectiveness and robustness of the proposed method. 相似文献
70.
Cuiling Ren Jinhua Li Jiefang Sun Xingguo Chen Zhide Hu Desheng Xue 《Journal of luminescence》2010,130(1):65-69
In this paper, a new kind of fluorescent nanomaterial with morin modified alumina core and silica shell was prepared. Samples were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), photoluminescent (PL) spectroscopy and fluorescence microscope. TEM results indicated that this material could be synthesized in nanometer range. PL spectra suggested that this new synthesized material was photostable and it showed nearly no dye leakage. This was because the dye molecules could form stable complex with the reactive aluminum cations on the surfaces of the alumina particles. The excitation and emission maxima of this new luminescent material were located at 420 and 493 nm, respectively. This new kind of luminescent nanomaterial was prepared by morin, AlCl3 and tetraethyl orthosilicate, which was very important for the large-scale and economic preparation luminescent nanoparticles because these precursors were inexpensive and the preparation process was convenient. 相似文献