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991.
992.
993.
Nano-porous Composites Based on Heteropolyacid Functionalized Ionic Liquid: Synthesis,Characterization, and Catalytic Performance in Esterification
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Functionalized ionic liquid samples (bmim-PW12) were synthesized by 1-butyl-3-methyl-imidazolium bromide (bmimBr) and 12-phosphotungstic heteropolyacid (PW12). The sam-ples were annealed at 100-450 oC and were characterized by Fourier transform infrared spec-troscopy, X-ray diffraction, scanning electron microscope, thermal gravity-DTG, brunauer emmett teller, and NH3-temperature programmed desorption. The results showed that the bmim-PW12 samples were crystal and maintained intact Keggin structure. The organic parts of those samples were partly decomposed at a temperature more than 350 oC. The sample annealed at 400 oC exhibited nano-porous structure, strong acidity, and excellent catalytic activity on the esterification of n-butanol with acetic acid. The higher ester yield was ob-tained when the mass ratio of catalyst over the reactants amount was 5% for bmim-PW12 catalyst annealed at 400 oC. 相似文献
994.
Youbao Wan Junhao Chu Shaoling Guo Lingxian Bo Tianyan Yu Bingkun Yu 《International Journal of Infrared and Millimeter Waves》2001,22(1):197-205
The potassium lithium niobate crystals have been grown up. The shapes of solid-melt interfaces which maintaining the steady growth of the potassium lithium niobate crystals have been described. The optical transmission spectrum of the crystal has been surveyed. The perfected crystals showed good Second Harmonic Generation properties. 相似文献
995.
H. Jory D. Wagner M. Blank S. Chu K. Felch 《International Journal of Infrared and Millimeter Waves》2001,22(10):1395-1407
A microwave system is described which allows testing of the quasi-optical mode converter in a gyrotron, which is completely assembled except for the attachment of the electron gun. Test results are presented for a TE6,2,1 gyrotron, and a similar design for a TE28,7,1 gyrotron is shown. 相似文献
996.
997.
Enhanced fatigue property of PZT thin films using LaNiO3 thin layer as bottom electrode 总被引:2,自引:0,他引:2
X.J. Meng J.L. Sun J. Yu G.S. Wang S.L. Guo J.H. Chu 《Applied Physics A: Materials Science & Processing》2001,73(3):323-325
A highly (100)-oriented metallic LaNiO3 film was prepared directly on a Si substrate by a simple metalorganic decomposition (MOD) technique using lanthanum nitrate
and nickel acetate as the starting sources. Subsequent Pb(Zr,Ti)O3 (PZT) thin films deposited on the LaNiO3-coated Si substrate were obtained by a modified sol–gel method. It was found that the PZT thin films began to form a single
perovskite phase at a low annealing temperature of 530 °C, and exhibited highly (100) orientation. A ferroelectric capacitor
of Pt/Pb(Zr,Ti)O3/LaNiO3/Si annealed at 600 °C displayed a good P-E hysteresis characteristic and was fatigue-free even after 1011 switching cycles.
Received: 25 May 2000 / Accepted: 9 August 2000 / Published online: 30 November 2000 相似文献
998.
Investigation has been carried out on the thermal performance of sintered miniature heat pipes with 3 mm outer diameter.
In the theoretical analysis, the influence of wick structure parameters is determined by using the theory of capillary limitation.
As a result, the degree of importance is found to be as follows: porosity, powder diameter and thickness of wick structure.
In the experiments, heat pipes with sintered dendritic copper powder wicks were fabricated and tested. The maximum heat transfer
rate is about 13 W with an effective heat pipe length of 20 cm. By adopting the formulae developed for both sintered spherical
powder and fiber and adjusting their proportion, the agreement between experimental results and prediction is found to be
quite good in the tested operation temperature range.
Received on 26 February 2001 相似文献
999.
The relationship between the transported ion current and the cathodic arc current is determined in a vacuum arc plasma source equipped with a curved magnetic filter. Our results suggest that the outer and inner walls of the duct interact with the plasma independently. The duct magnetic field is a critical factor of the plasma output. The duct transport efficiency is to maximize at a value of bias plate voltage in the range +10 V to +20 V, and independent (within our limit of measurement) of the magnetic field strength in the duct. The plasma flux is composed of two components: a diffusion flux in the transverse direction due to particle collisions, and a drift flux due to the ion inertia. The inner wall of the magnetic duct sees only the diffusion flux while the outer wall receives both fluxes. Thus, applying a positive potential to the outer duct wall can reflect the ions and increase the output current. Our experimental data also show that biasing both sides of the duct is more effective than biasing the outer wall alone. 相似文献
1000.
Lichang Yin Yunzuo Liu Jingbin Lu Guangyi Zhao Xianfeng Li Xiaoguang Wu Guangsheng Li Shuxian Wen Chunxiang Yang 《The European Physical Journal A - Hadrons and Nuclei》2001,11(4):379-383
High-spin states of 160Lu have been studied through the 144Sm( 19F, 3n) reaction. The previously known πh
11/2⊗υi
13/2 yrast band is extended from I
π = 21- to 25- and a four quasiparticle band with configuration πh
11/2[523]7/2 -⊗υh
9/2[521]3/2 -⊗ (υi
13/2)2 is reported.
Received: 21 May 2001 / Accepted: 19 July 2001 相似文献