Synthesis of amphiphilic magnetic microspheres by dispersion copolymerization of styrene and poly(ethylene oxide) macromonomer

Amphiphilic magnetic microspheres ranging in diameter from 5 to 100 µm were prepared by dispersion copolymerization of styrene and poly(ethylene oxide) vinylbenzyl (PEO‐VB) macromonomer (MPEO) in the presence of Fe₃O₄ magnetic fluid. The effects of various polymerization parameters on the average particle size were systematically investigated. The average particle size was found to increase with increasing styrene concentration and initiator concentration. It also increased with decreasing stabilizer concentration and molecular weight of MPEO. The content of the hydroxyl groups localized in the microspheres ranged from 0.01 to 0.2 mmol g^?1. © 2003 Society of Chemical Industry     

Opening-up Status of China＇s Oil ＆ Gas Market

Since the founding of P.R.China,Particularly after the lauch of reform and opening up in 1978,China＇s oil and gas industry has undergone a series of significant reforms and restructuring.it has set up a complete oil and gas industry system.     

Studies on high density polyethylene (HDPE) functionalized by ultraviolet irradiation and its application

The structure and properties of high density polyethylene (HDPE) functionalized by ultraviolet irradiation at different light intensities in air were studied by electron analysis, FTIR spectroscopy, contact angle with water, differential scanning calorimetry and mechanical properties measurement. The results show that oxygen‐containing groups such as C?O, C—O and C(?O)O were introduced onto the molecular chain of HDPE following irradiation, and the rate and efficiency of HDPE functionalization increased with enhancement of irradiation intensity. After irradiation, the melting temperature, contact angle with water and notched impact strength of HDPE decreased, the degree of crystallinity increased, and their variation amplitude increased with irradiation intensity. Compared with HDPE, the yield strength of HDPE irradiated at lower light intensity (32 W m^?2 and 45 W m^?2) increases monotonically with irradiation time, and the yield strength of HDPE irradiated at higher light intensity (78 W m^?2) increases up to 48 h and then decreased with further increase in irradiation time. The irradiated HDPE behaved as a compatibilizer in HDPE/polycarbonate (PC) blends, and the interface bonding between HDPE and PC was ameliorated. After adding 20 wt% HDPE irradiated at 78 W m^?2 irradiation intensity for 24 h to HDPE/PC blends, the tensile yield strength and notched Izod impact strength of the blend were increased from 26.3 MPa and 51 J m^?1 to 30.2 MPa and 158 J m^?1, respectively. Copyright © 2003 Society of Chemical Industry     

Monte Carlo simulation of gas phase polymerization of 1,3‐butadiene. Part II: Kinetics optimization and confirmation

Studies on the deactivations and initiations of gas phase polymerizations of 1,3‐butadiene have been achieved by Monte Carlo simulation. Initiation and deactivation control the reaction before and after the peak of the polymerization rate, respectively. The influence of polymerization temperature has been studied. Monte Carlo modeling of polymerization kinetics and mechanism was confirmed by the agreement of experimental data and simulation results of polymerizations run with a temporary evacuation of monomer. The balance of catalysts and active chains is established by both initiation and chain transfer reactions with cocatalyst, which causes a ‘pseudo‐stability’ stage. © 2003 Society of Chemical Industry     

通用串行总线(USB)接口芯片USBN9602的应用

简要介绍了通用串行总线USB的特点,对USB接口芯片USBN9602的内部结构、引脚、寄存器组作了详细的论述,并介绍了其应用。     

Bandpass filters with reconfigurable transmission zeros using varactor-tuned tapped stubs

In this letter, bandpass filters with one or two tunable transmission zeros are proposed. The reconfigurable transmission zeros are implemented through varactors in combination with tapped quarter-wavelength stubs. Based on mixed mode simulations including EM simulation and circuit simulation, the proposed filters were designed and fabricated on low-cost FR4 board. The measurement results verified the design concepts.     

洗衣机脱水桶注射模设计

通过对洗衣机脱水桶塑料成型件的特性分析,简要介绍了其成型模具的设计和有关参数的计算方法。     

~（131）Ⅰ—MIBG比活度对鼠心肌交感神经囊泡内外摄取的影响

研究了两种比活度的１３１Ⅰ－ＭＩＢＧ在正常及利血平抑制后在鼠体内的分布，结果表明：注射后４ｈ，正常鼠心肌对３．２２ＴＢｑ／ｇ的ＭＩＢＧ摄取为９．０８％ＩＤ／ｇ，明显高于对１８．５ＧＢｑ／ｇ的摄取（４．８７％ＩＤ／ｇ）。计算表明，比活度主要影响了鼠心肌交感神经囊泡内摄取，而与囊泡外摄取无关．当ＭＩＢＧ用于心肌显像时，高比活度的ＭＩＢＧ有利于诊断。