New polyimide–silica organic–inorganic hybrids

A series of polyimide–silica hybrid films with silica contents up to 30 wt % were successfully prepared by the sol‐gel reaction of tetraethoxysiliane in the presence of poly(amic acid) containing pendent hydroxyl groups. The films were yellow and transparent when the silica content was less than 11 wt %. The chemical structure of the films was characterized by Fourier transform infrared spectroscopy, and the morphology of the films was investigated by scanning electronic microscopy and atomic force microscopy. Thermogravimetric analysis, differential scanning calorimetry, and stress–strain tests were used to measure the performance of the films. The results indicate that the glass‐transition temperatures and decomposition temperatures of the hybrid films increased with increasing silica content, whereas the tensile strength had a maximum with the variety of silica contents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2210–2214, 2003     

Seeded Crystallization of Leucite

The leucite crystallization kinetics from a hydrothermally derived precursor seeded with nano-crystalline leucite was investigated by X-ray diffraction and non-isothermal differential thermal analysis. The nano-crystalline leucite was prepared by high-energy milling of high-purity leucite powder and the leucite precursor was prepared by the hydrothermal method of silica sol, aluminum nitrate, and potassium nitrate. After the seeds were introduced, the crystallization temperature of the precursor was lowered by 100°C and the transition phase kalsilite did not appear during the crystallization process. When the seeded precursor was heat treated at 700°C, a small amount of cubic leucite was stabilized to room temperature. The seeded precursor showed an exothermic peak between 800° and 920°C under different heating rates. The activation energy for the growth of leucite from the seeded precursor was 256(SD9) kJ/mol.     

Decolorisation and mineralisation of CI Reactive Black 8 by the Fenton and ultrasound/Fenton methods

The effects of pH, ferrous ion and hydrogen peroxide dosage on the decolorisation and mineralisation of CI Reactive Black 8 by the Fenton process with/without ultrasonic irradiation were investigated. It was verified that the presence of ultrasonic irradiation did not enhance the decolorisation of CI Reactive Black 8 significantly by Fenton's reagents, but it enhanced the chemical oxygen demand removal efficiency. The enhancement was more pronounced for lower (<0.89 mm) or higher (>1.78 mm) ferrous ion dosage. The optimal pH for chemical oxygen demand removal was 3.0. Chemical oxygen demand removal efficiency increased with the increasing H₂O₂ dosage and reached the highest level at 5.88 mm, but further increase in H₂O₂ dosage would not increase removal efficiency significantly.     

机动车制动液的研制

介绍了合成型机动车制动液的生产和配方，讨论了物料组成对产品的影响。     

高职院校信息安全课程体系优化与教学内容改革的研究

从提高学生职业能力理念出发,以高素质技能型人才培养为目标,教学改革和课程体系设计为先导,整合信息安全课程体系并进行优化,构建人才培养新方案,对教学内容进行有效探索,以期提高信息安全专业人才培养质量.     

Interbay物料自动搬运系统性能分析

Interbay物料自动搬运系统的运行效率对于晶圆制造系统影响较大,研究Interbay物料自动搬运系统的绩效具有较大的意义[1]。该文以带有捷径的单闭环背脊式布局的物料自动搬运系统为研究对象,通过问题描述,简化、假设将实际问题抽象为导引运输模型。然后,建立数学模型,采用Dijkstra算法确定工件搬运的最短路径。最后,利用Arena仿真软件建立含有导引运输设备的模型,采用控制变量法探究小车数量小车占用轨道的方式、调度规则等因素对于产出的影响,发现对于本文中的模型,其它条件相同时,搬运系统采用Release-at-end的控制方式,系统最大搬运量越大。     

A two‐station embossing process for rapid fabrication of surface microstructures on thermoplastic polymers

An embossing strategy involving a hot station and a cold station for sequentially heating and cooling the embossing tool was investigated to reduce cycle times in hot embossing polymer microstructures. Experimental studies showed that aluminum stamps with a thickness of 1.4 mm can be rapidly heated from room temperature to 200°C in 3 s using contact heating against a hot station at 250°C. Microchannels and microlenses were successfully embossed onto high‐density polyethylene and acrylonitrile–butadiene–styrene substrates using a heating time less than 3 s and a total cycle time around 10 s. The two‐station embossing process for the microlens was also numerically studied. The simulated filling behavior agreed with the experimental observation and the predicted thermal and deformation history of the polymer offered a good explanation on the experimentally observed process characteristics. POLYM. ENG. SCI., 47:530–539, 2007. © 2007 Society of Plastics Engineers.     

The kinetics of B‐a and P‐a type copolybenzoxazine via the ring opening process

The structure of benzoxazines is similar to that of phenolic resin through thermal self‐curing of the heterocyclic ring opening reaction that neither requires catalyst nor releases any condensation byproduct. These polybenzoxazine resins have several outstanding properties such as high thermal stability and high glass transition temperature. To better understand the curing kinetics of this copolybenzoxazine thermosetting resin, dynamic and isothermal differential scanning calorimetry measurements were performed. Three models, the Kissinger method, the Flynn–Wall–Osawa method, and the Kamal method, were used to describe the curing process. Dynamic kinetic activation energies based on Kissinger and Flynn–Wall–Osawa methods are 72.11 and 84.06 KJ/mol, respectively. The Kamal method based on an autocatalytic model results in a total order of reaction between 2.66 and 3.03, depending on curing temperature. Its activation energy and Arrhenius preexponential are 50.3 KJ/mol and 7959, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 730–737, 2005     

"团队项目训练法"在市场营销实践教学中的应用——以"与爱同行"营销策划综合训练为例

“团队项目训练法”是充分利用各种市场资源,按照市场营销工作实际,让学生自组团队、自寻商机、自设项目,理论联系实际分析营销环境．对真实对象进行市场营销方案设计、实施、评估,亲历市场营销的完整过程,以此进一步掌握理论,训练技能,提高能力。介绍了重庆科技学院对市场营销专业本科生运用“团队训练法”进行实践教学的做法及效果。     

Preparation of micro-patterned surfaces of Si-N-O films and their influence on adhesion behavior of endothelial cells

Microgrooves were prepared on Si(100) surface by photolithography and wet etching.Subsequently,Si-N-O films were deposited on the microgrooves by unbalanced magnetron sputtering(UBMS) and micro-patterned surfaces of Si-N-O films were obtained.The size of the micropatterns was measured by surface profilometer.The chemical composition of Si-N-O films were characterized by X-ray photoelectron spectrometry(XPS) and the wettability of the micropatterned surfaces was evaluated by contact angle measurement.The beh...