PE/CaCO3-nanocomposites synthesized by in-situ polymerization

Polyethylene-nanocomposites with CaCO3-weight fractions from 0 to 15 wt.% were prepared by in-situ polymeriza- tion with Me2Si(Ind)2ZrCl2/MAO metallocene catalysts. A high activity especially in the presence of TIBA was observed. The morphology was investigated by using raster electron microscopy (REM) showing that the CaCO3-nanoparticles are uniformly distributed. The melting temperatures and the crystallization temperatures are not much influenced by increasing filler content.     

Vibration and sound damping in polymers

Excessive vibrations or loud sounds cause deafness or reduced efficiency of people, wastage of energy and fatigue failure of machines/structures. Hence, unwanted vibrations need to be dampened. This article describes the transmission of vibrations/sound through different materials such as metals and polymers. Viscoelasticity and glass transition are two important factors which influence the vibration damping of polymers. Among polymers, rubbers exhibit greater damping capability compared to plastics. Rubbers reduce vibration and sound whereas metals radiate sound. The damping property of rubbers is utilized in products like vibration damper, shock absorber, bridge bearing, seismic absorber, etc.     

From opportunity to reality: transition into engineering education,trauma or transformation?

ABSTRACT

Transition into university can prove to be a challenging time for young people entering engineering education, irrespective of previous educational experience or demographic background. It is such challenges that this article considers. Commencing by looking at the pragmatic issues associated with transition, the question of whether starting university is a time of transformation or trauma for new engineering students is discussed. Following this, a conceptual framework grounded in the authors previous work depicts a tripartite approach to transition, identifying three interlinked phases that new students typically encounter. The conclusion suggests that through the introduction of realistic and socially relevant engineering activities, transition into engineering education is the ideal time to turn opportunity into reality for new students.     

高分子生物材料的组织工程支架成形方法

多孔支架是组织工程的重要要素,高分子材料是制作支架的主要材料。而快速成形技术以其复杂形状成形能力、可控的连通孔造孔能力成为组织工程支架制备的一种崭新方法。讨论了组织工程对支架性能的要求,介绍了常用高分子材料作为支架主要特性以及相关的成形方法。通过与传统支架制备方法的对比,阐述了快速成形技术的优势。     

Synthesis and Characterization of Novel Copolymers Based on 3 （S）-Methyl-Morpholine-2,5-Dione

A series of novel copolymers were successfully synthesized by ring-opening polymerization(ROP) of 3(S)-methyl-morpholine-2,5-dione(MMD) and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one(MBC) using stannous octoate as catalyst.The copolymers were characterized by means of 1 H-NMR and FT-IR spectroscopy.Gel permeation chromatography(GPC) test shows that the average-number relative molecular mass and average-weight relative molecular mass slightly increase with the increase of MBC content in feed.The results of differential scanning calorimetry(DSC) demonstrate that the glass transition temperature of copolymers increases with the increase of MBC content in copolymers.The copolymers of MMD and MBC are amorphous copolymers,as indicated by DSC results,while the homopolymer of MMD is semicrystalline.     

《工程塑料模塑塑料件尺寸公差》标准的解析表达

<工程塑料模塑塑料件尺寸公差标准>是国家规范和指导模塑塑料制件设计与生产的基础性文件.由于此标准采用表格形式表达模塑件基本尺寸与其制造公差的关系,因而存在一些局限.通过分析发现该关系在很大范围内可以采用解析式表达.以解析式表达不但可以克服表格式表达的局限,而且在计算机条件下使用起来更加便捷准确.     

利用废塑料热解-催化改质制备汽油的研究

研究了几种改性HY分子筛对高密聚乙烯废塑料的热解-催化改质性能，讨论了催化剂的表面酸性与油品收率、组成的关系；比较了最优催化剂4#对LDPE、HDPE、PP、PS及混合塑料的改质效果；提出了利用废塑料制取高辛烷值汽油的有效方法．     

聚合物的分子拓扑结构与物性的关联

应用分子拓扑指数来定量描述分子结构，采用遗传算法来选择与物性相关的分子连接性指数，通过多元线性回归分析建立分子拓扑结构与物性的关联方程，采用此方法，本研究了66种聚合物的玻璃化温度（Tg)与分子拓扑结构的关系，并对12种聚合物的玻璃化温度进行了推算，结果表明聚合物的玻璃化温度与分子连接性指数有较好的相关性。     

基于神经网络的转换GPS高程的新方法

GPS高程是相对于WGS-84椭球体的大地高,因此,在工程应用中,GPS高程需要转换为正常高.转换GPS高程通常采用二次曲面拟合法(CFM)和神经网络方法(NNM),但这2种方法各有优缺点.在研究了这2种方法之后,提出了一种转换GPS高程的新方法,该方法综合了上述2种方法的优点,故取名为“CF&NNM”方法.介绍了CF&NNM方法的思路和计算过程.通过一个工程实例,列出了上述3种方法的数据处理结果,新方法效果最好.对CF&NNM方法进行了理论分析.     

Introduction to Enhanced Protective Film Systems

An explosive blast mitigation alternative has increased the safety of structures by using "catcher" systems.These systems " catch" or repel the failure of the window or in-fill wall protecting life and property from ballistic shards or fragments.They can be designed to be standalone in new construction and structural retrofits or used to augment structural hardening techniques.Cables,fabrics,and thin gauge sheet steel are examples of catcher systems used in the past.A new and evolving category of catcher systems are based on polymeric materials that can be used for both wall and window upgrades.These products are a proven blast mitigation concept and K&C Protective Technologies Pte Ltd (KCPT) together with Sherwin-Williams(SW) use KCPT's blast engineering capacity and SW's material engineering principles to create engineered systems for even greater in-use performance.     

邻氯二苯醚改性聚芳醚酮酮的合成与表征

本文以自制的邻氯二苯醚为改性第三单体,使之与对策二甲酰氯（TPC）,二苯醚（DPE）,在无水AlCl3/l,2－二氯乙烷／Lewis碱催化溶剂体系中进行三元无规共缩聚,制得一系列含侧基氯取代的聚芳醚酮酮（Cl-PEKK),并对它们进行了分析表征。     

PP管件的注塑模具设计与制造研究

PP管件具有优良的电绝缘性能和化学稳定性,与绝大多数化学品接触不发生作用,可用作工程塑料。通过对其注塑模具的设计与制造进行分析,阐述了模具设计、模具制造、工作原理,目的是为更好地优化模具设计,延长模具使用寿命。     

Recent Progress on Carbonaceous Material Engineering for Electrochemical Hydrogen Peroxide Generation

Electrochemical synthesis of hydrogen peroxide(H_2 O_2) provides a clean and safe technology for large-scale H2 O2 production.The core of this project is the development of highly active and highly selective catalysts.Recent studies demonstrate that carbonaceous materials are favorable catalysts because of their low-cost and tunable surface structures.This brief review first summarizes the strategies of carbonaceous material engineering for selective two-electron O_2 reduction reaction and discusses potential mechanisms.In addition,several device designs using carbonaceous materials as catalysts for H_2 O_2 production are introduced.Finally,research directions are proposed for practical application and performance improvement.     

Fostering wise judgement: professional decisions in development programmes for early career engineers

This paper reviews literature that explores the role of judgement in professional practice. It discusses how workplace decisions, work activities and reflection on these activities may contribute to the development of wise judgements, or ‘wisdom’, and how workplaces can leverage these activities for induction and transition to work programmes. This review of the literature is prompted by survey results inviting engineering graduates and professionals to identify the capabilities they believe are most significant to success in the engineering workplace. The requirement for sound professional judgement resonates in participant responses. The paper summarises views of expertise, the relationship between experience and the development of professional judgement and the broader contribution of expansive and participatory learning environments to developing professional judgement. It concludes that the organisation of work and job design can facilitate the articulation of new engineers to professional practice, and that organisational learning programmes can leverage workplace activities to foster wise judgement in graduate engineers.     

KOH/DMSO促进的Sonogashira偶联反应

在无过渡金属催化剂和无配体存在下,KOH/DMSO超强碱能够促进Sonogashira偶联反应。碱的类型、溶剂对Sonogashira反应的影响,以及底物的范围做了考察。研究结果表明：在没有钯或铜和配体形成的催化剂、也没有相转移试剂存在下,在比较温和的反应条件下,强碱就可以促进Sonogashira反应。     

联二萘酚双钠盐催化的Henry反应研究

Henry反应是重要的形成碳碳键的反应之一,在有机合成中有着广泛应用.通常的henry反应催化剂为强酸或者强碱,能否找到一种温和的催化剂来催化此反应呢?通过筛选,我们发现在催化剂量的联二萘酚双钠盐(3 mol %)存在下,henry反应能够快速的进行,产率高达100%.此催化剂催化的henry反应不但反应迅速而且条件温和.     

Challenges of engineering higher education in a transitional economy: a Russian experience

Education and training serve as critical elements of advancement of a nation’s economy in transition. The restructuring of the power engineering industry in Russia has called for a fast implementation of new management system in electric power engineering and radical training of professional managers at different levels in organizations. Management training in electric power engineering in Russia has been implemented by (1) preparing highly professional managers in higher education institutions and technical universities and by (2) improving the management skills of practicing managers in technical universities and educational centers of different power energy companies. This article reports the experience of introducing a new discipline ‘Management in Electrical Engineering’ at the Moscow Power Engineering Institute (Technical University) and reflects on training managers in electric power engineering at higher education and corporate educational centers.     

Programme Quality Assessment by the Implication of Variable Entry Qualifications on Students' Performance

Since its inception 30 years ago, the then Department of Engineering Science, Institut Teknologi MARA (ITM) was given the responsibility of preparing all the students in the first year engineering programmes by giving enough knowledge in basic science and mathematics. The nation's vision to become a fully‐industrialised economy by the year 2020 required all institutes of higher learning (IHLs) in Malaysia to increase their intake of students in the science and technology courses, especially in engineering. However, at the upper secondary education level, students have the freedom to choose between the science‐based or non‐science combination of subjects. This has led to a dearth of science‐based students enrolling in IHLs. Because ITM believes that it is possible to educate individuals from various backgrounds, the engineering courses are open to students with a variety of academic qualifications. Special bridging courses were designed and created for such students since late 1996. The success or failure of the new courses can be assessed after the students have gone through the proper first year engineering courses which consist of Mathematics, Physics and Chemistry. This paper reports on a pilot study on the pioneer groups of students with variable entry qualifications to assess the effectiveness of the courses. The study involved the analysis of the students’ examination results as a performance indicator, and it was found that the bridging programme for non‐science students needed to be redesigned. It is also proposed that to improve the quality of the programme, and hence students’ performance, a regular review be conducted, student support activities be continued and to expand the use of self‐study materials.     

农民工权益保障所面临的法律制度问题和对策

农民工是社会转型时期出现的新的特殊阶层。由于没有城市居民身份,他们被排除在社会保障安全网之外,合法利益得不到法律的有效保障。文章从法律的视角,分析了保障农民工权益的法律缺失的现状,并提出了构建农民工权益法律保障体系的若干建议。     

Curve smoothing using a continuous function

Current curve smoothing technologies provide a smoothed curve by joining together separate curves that have certain degrees of continuity at junctions. These technologies have found many applications in science and engineering. However, none of them can provide a smoothed curve using a single continuous function for arbitrary segmental curves. This paper reports a new approach that can be used to construct a single continuous function that joins an arbitrary number of different segmental curves, with the required degree of continuity at all junctions. The smoothness of transition at different junctions can be controlled by separate parameters to suit different needs. The combined continuous function can approach the original segmental functions asymptotically or match the original segmental functions “exactly” inside each segment by adjusting the smoothness parameter. This new approach may also find application outside the scope of curve smoothing/curving fitting in the future.