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991.
Air-breathing mode laser propulsion experiment with a long-pulse transversely excited(TE) CO2 laser is carried out,and its ignition problem is solved with the ignition needle of lightcraft.Owing to the ignition needle,an order of magnitude reduction in the ignition threshold is demonstrated.The result is compared with previous study.The momentum coupling coefficient is also measured in the experiment and its dependence upon laser pulse energy(6-14 J) and pulse width(20,32,and 40μs) is discussed. 相似文献
992.
根据高炉冲渣水的余热特点,提出了一个采用分离式热管换热器的余热回收的方案。文中对余热回收方案中换热设备的结构特点进行了描述。 相似文献
993.
System calibration, which usually involves complicated and time-consuming procedures, is crucial for any three-dimensional (3D) shape measurement system based on vision. A novel improved method is proposed for accurate calibration of such a measurement system. The system accuracy is improved with considering the nonlinear measurement error created by the difference between the system model and real measurement environment. We use Levenberg-Marquardt optimization algorithm to compensate the error and get a good result. The improved method has a 50% improvement of re-projection accuracy compared with our previous method. The measurement accuracy is maintained well within 1.5% of the overall measurement depth range. 相似文献
994.
Geng-Dong Cheng 《Acta Mechanica Sinica》2010,26(6):793-794
The first version of Acta Mechanica Sinica (AMS) was launched in June 1985 in Beijing, aimed at delivering the cutting-on-edge progress and achievement in Mechanics in China to the world, allowing world-round colleagues to access the work of Chinese mechanician, and supplying an international forum in the field. Its appearance was a result of 5-year preparation after the consensus agreement by the Acta Mechanica Sinica Editorial Board (3rd), and was approved by the China Association for Science and Technology and supported by the Chinese Society of Theoretical and Applied Mechanics (CSTAM). 相似文献
995.
Two new coordination polymers, [Na(H2L)(H2O)2]n ( 1 ) and [Ba(H2L)2(H2O)]n ( 2 ) (H3L = 3‐formyl‐4‐hydroxybenzenesulfonic acid) were synthesized and structurally characterized. The H2L– ligand shows three different bridging modes, μ3 in 1 , μ3 and μ4 in 2 . Compound 1 presents a 2D pillared structure, whereas 2 forms a 3D framework. Both 1 and 2 show blue luminescence at 380 nm in aqueous solution, however, their solid state emissions are at 406 and 446 nm, respectively. 相似文献
996.
Cheng‐Hung Chang Kun‐Li Wang Jyh‐Chiang Jiang Der‐Jang Liaw Kueir‐Rarn Lee Juin‐Yih Lai Kuo Yuan Chiu Yuhlong Oliver Su 《Journal of polymer science. Part A, Polymer chemistry》2010,48(24):5659-5669
A series of highly organosoluble polyamides with high modulus having propeller‐shaped triarylamine were synthesized using aromatic diacid chlorides by low‐temperature solution polycondensation. The polyamide films had strong, tough, flexible, and amorphous properties. These polymers revealed electrochromic characteristics both in the visible range and near‐infrared (NIR) region, with a color change from pale yellowish at its neutral state to green and blue at its oxidized state at applied potentials ranging from 0.00 to 1.35 V. Cyclic voltammetry (CV) of the polymer films cast onto an indium tin oxide (ITO)‐coated glass substrate exhibited two reversible redox couples at potentials of 0.80–0.87 V and 1.19–1.25 V, respectively, vs. Ag/Ag+ in acetonitrile solution. From the combination of the experimental and computational study, we proposed an oxidation mechanism based on molecular orbital (MO) theory, which well explains the CV experimental result. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
997.
998.
Hsiu‐Li Lin T. Leon Yu Cheng‐Hung Huang Tsang‐Lang Lin 《Journal of Polymer Science.Polymer Physics》2005,43(21):3044-3057
The structures of Nafion membranes prepared by solutions casting from low aliphatic alcohols/water mixture solvents and N,N′‐dimethyl formamide (DMF) solvent were investigated using differential scanning calorimeter and small angle X‐ray scattering. The aggregation behavior of Nafion molecules in the casting solutions was also investigated using dynamic light scattering. We show that the morphology of membranes was strongly influenced by the conformations of Nafion molecules in the solutions. In aliphatic alcohol/water mixture solvents, which have a worse compatibility with Nafion backbones, the Nafion molecules aggregate and form fringed rod‐like structures. These primary rod‐like structures then aggregate again through fringed side chains to form secondary ionic aggregations. In DMF solvent, owing to its better compatibility with Nafion backbones, less Nafion molecules aggregate. The high degree of Nafion molecular aggregations in aliphatic alcohol/water mixture solvents leads to a high degree of hydrophobic and hydrophilic phase separation for membranes prepared by casting from Nafion/aliphatic alcohol/water solutions. However, the lower degree of molecular aggregations in DMF solvent results in a lower degree of hydrophobic and hydrophilic phase separation for membranes prepared by casting from Nafion/DMF solution. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3044–3057, 2005 相似文献
999.
Wei Shuo FANG* Qi Cheng FANG Xiao Tian LIANG Institute of Materia Medica Chinese Academy of Medical Sciences Peking Union Medical College Xian Nong Tan Street Beijing 《中国化学快报》2001,(8)
Numerous efforts towards synthesis of anticancer drug paclitaxel (Taxol(r), 1a) with improved activities led to the modification at 13-phenylisoserine side chain and different positions of its core structure-baccatin III 1c1. At the same time, the activities of searching new taxoids for starting materials of new semi-synthetic paclitaxel analogs from Taxus spp. plant have not ever been stopped. Among these taxoids, 14?-hydroxy-10-deacetylbaccatin III 22 and 13-acetyl-9-dihydrobaccatin III … 相似文献
1000.
J. C. Huang C. H. Cheng Y. F. Chen S.R. Sheen Z. L. Lee H. Y. Shao M. K. Wu 《中国化学会会志》1999,46(2):173-178
A highly homogeneous and nearly monophasic PrBa2Cu4O8 compound has been synthesized at 1 atm of oxygen via a route employing polymeric ethylenediamine/citric acid precursors. The PrBa2Cu4O8 compound with a trace amount of BaCuO2 was synthesized for the first time by sintering the pellets at the temperature of 875 °C under ambient oxygen pressure. The temperature coefficient of the resistivity is positive below 190 K while above 190 K is negative. The superconducting transition was not detected down to 4.2 K. Samples were characterized by X-ray diffraction, scanning electron microscopy, thermal analysis, and transport and magnetic measurements. 相似文献