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991.
992.
介绍了激光光声检测技术在快速凝聚相相变和化学反应中的应用,阐述了检测原理、测试技术和研究进展。 相似文献
993.
994.
The primary conclusion derived in this paper is that the leading principal minors of matrixB-ωA (whereB is a symmetric positive definite matrix andA is Hermite matrix) have properties similar to those of Sturm sequences, which is the theoretical basis of the Determinant Search Method for solving the eigenvalue-problem of damped structural systems [1]–[5], correcting the errors in a statement given by K. K. Gupta in [1]–[5]. 相似文献
995.
Dai D He S 《Journal of the Optical Society of America. A, Optics, image science, and vision》2004,21(1):113-121
With a perfectly matched layer boundary treatment, a semivectorial finite-difference method is used to calculate the eigenmodes of a single-mode (SM) or multimode (MM) bent rib waveguide. A detailed analysis is given for the dependence of the bending losses (including the pure bending loss and the transition loss) on geometrical parameters of the bent rib waveguide such as the rib width, the rib height, and the bending radius. The characteristics of the higher-order modes are analyzed. It is shown that the bending loss of the fundamental mode can be reduced effectively by increasing the width and height of the rib. For an integrated device, undesired effects due to the higher-order modes of a MM bent waveguide can be removed by appropriate choice of the geometrical parameters. An appropriately designed MM bent waveguide is used to reduce effectively the bending loss of the fundamental mode, and a low-loss SM propagation in a MM bent waveguide is realized when the bending losses of the higher-order modes are large enough. 相似文献
996.
固定床费托合成Co/SiO2催化剂研究 总被引:1,自引:0,他引:1
系统考察了载体粒径大小、添加助剂、及活性组分的不均匀分布对Co/SiO2催化剂反应性能的影响.结果表明随着粒径的增大,由于扩散控制的影响,催化剂的活性快速下降.采用添加助剂、制备"蛋壳"型催化剂可大幅提高其费托反应活性.所制备的含助剂"蛋壳"型催化剂Co/SiO2在温度230℃,压力1.2 MPa,空速500 h-1条件下,CO转化率为74.17%,C+5选择性为85.55%. 相似文献
997.
Lectin affinity chromatography was miniaturized into a microfluidic format, which results in improvement of performance, as compared to the conventional method. A lectin affinity monolith column was prepared in the microchannel of a microfluidic chip. The porous monolith was fabricated by UV-initiated polymerization of ethylene dimethacrylate (EDMA) and glycidyl methacrylate (GMA) in the presence of porogeneities, followed by immobilization of pisum sativum agglutinin (PSA) on the monolith matrix. Using electroosmosis as the driven force, lectin affinity chromatographies of three kinds of glycoprotein, turkey ovalbumin (TO), chicken ovalbumin (CO), and ovomucoid (OM), were carried out on the microfluidic system. All the glycoproteins were successfully separated into several fractions with different affinities toward the immobilized PSA. The integrated system reduces the time required for the lectin affinity chromatography reaction to approximately 3%, thus, the overall analysis time from 4 h to 400 s. Only 300 pg of glycoprotein is required for the whole separation process. Moreover, troublesome operations for lectin affinity chromatography are simplified. 相似文献
998.
Extraction of cesium ions from aqueous solutions using calix[4]arene-bis(tert-octylbenzo-crown-6) in ionic liquids 总被引:3,自引:0,他引:3
Luo H Dai S Bonnesen PV Buchanan AC Holbrey JD Bridges NJ Rogers RD 《Analytical chemistry》2004,76(11):3078-3083
Solvent extraction of cesium ions from aqueous solution to hydrophobic ionic liquids without the introduction of an organophilic anion in the aqueous phase was demonstrated using calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) as an extractant. The selectivity of this extraction process toward cesium ions and the use of a sacrificial cation exchanger (NaBPh(4)) to control loss of imidazolium cation to the aqueous solutions by ion exchange have been investigated. 相似文献
999.
We report an experimental result that shows the excitation of surface plasmon polaritons by use of a zeroth-order Bessel beam. From the viewpoint of energy efficiency, the zeroth order Bessel beam is ideal for the local excitation of surface plasmon polaritons on a metal film. We introduce an optical setup using an axicon element in order to carry out the excitation. 相似文献
1000.
K. Yamaura T. Katoh K. Koezuka M. Iwaseya Lixing Dai 《Journal of Materials Science》2004,39(5):1609-1614
The NaCl/water solutions of commercial poly(vinyl alcohol) (a-PVA) with the degrees of polymerization and saponification of 1730 and 99.39%, respectively were gel-spun into methanol (–30°C) and then the removed NaCl dry-filaments were drawn at 200°C. The draw ratio showed the maximum at NaCl concentration C
N = 3 wt% (polymer concentration C
P = 150 kg/m3). The Young's modulus and strength at break were 95 and 6 GPa ( = 19). In the case of DMSO system (C
P = 170 kg/m3), the Young's modulus was 52 GPa ( = 25) and the strength at break was 3.3 GPa. Under a polarized microscope, the fine lateral structure was observed for the DMSO system, but not for the NaCl system, that is, the smooth structure was recognized. The smooth structure, like a Netlon packing net for oranges, might be considered to result in heightening of mechanical properties. 相似文献