治理环境污染营造绿色未来

蔚蓝的天空,绿色的田野,清新的空气,葱郁的山峦,茂密的森林,清澈的河流,明净的湖泊,湛蓝的海洋,是地球固有的风貌,人类生息的摇篮。然而,伴随着近代工业文明的兴起与发展,人类在索取自然资源,建立现代文明过程中,由于肆无忌惮地掠取自然财富,无所顾及地丢弃各种废弃物,无视生态环境的发展规律,从而导致了自然界的无情惩罚与报复,使人与自然界的关系由和谐走上了相互抵触的道路。因此,面对生态环境的严峻挑战,作为一名理工科大学生,不仅应努力学习现代工程技术的科学知识,同时还应科学地关注人类面临的生态环境,认真思考人与自然的关系,     

聚甲基丙烯酸甲酯新应用发展近况

追溯代表性的透明塑料的历史,先后相继工业化的是：聚氯乙烯1927年,聚苯乙烯1930年,甲基丙烯酸甲酯1936年,聚碳酸酯1958年,这些透明塑料当,因甲基丙烯酸甲酯树脂具出类拔萃的透明性,表面光泽,优良的耐候性,以及良好的机械特性等综合性能,被广泛用于汽车部件,弱电零部件,光学元件,广告板,显示器,照明,建材,日用杂品等,在日本其年产量约为20万吨左右,近年来,对甲基丙烯酸甲酯的物性也提出了多种多样,高层次的要求（耐冲击性,耐热性,耐溶剂性,低吸湿性,阻燃性,耐擦伤性,抗静电性,防雾性,波长选择吸收性,防污性,低反射性等）,为此,针对不同用途的要求进行了质量和技术开发,此外,在近几年,随着显示材料领域的迅猛发展与其市场的扩大,通过灵活运用甲基丙烯酸甲酯本身特有的透明性进行材料设计,提供更高的光学功能,各种光学元,器件对甲基丙烯酸甲酯的需要量正在不断增长。     

思考

各种各样的展览信息,不时充斥在各种相关媒体上,全国的,地方的,行业的,机构的,企业的,社会性的,公益型的……凡此种种,但都有一个共性,那就是都有相关的权威机构作为主办单位,有一定的规模,可产生一定的影响,并设有一定的奖项。参展商们也就冲着这些因素而来。     

大和胜杰MVL-700

大和胜杰生产的MT-206MC机床主要用于精密复杂的各种回转体零件的多品种,中大批量加工．能满足通常的内圆,外圆,台阶,锥面,球面,沟槽,各种螺纹和复杂曲面的加工,能够满足各类高温合金,钛合金,耐热合金,不锈钢,铸铁,铸钢等材料的铸锻件毛胚件的粗,精加工．机床可靠性好,刚性好,精度高,寿命长,能可靠稳定地完成各种难加工材料的粗,细,精加工．     

氮化硅陶瓷：极具前途的轴承用材

近几年来,随着社会进步和科学技术的高速发展,轴承的使用环境和条件越来越多样化,对轴承的结构,材质和性能的要求也越来越高,一些高科技领域和某些特殊环境下工作的机械,如航空航天,核能,冶金,化工,石油,仪器,机械,电子,纺织,制药等工业,需要在高温,高速,高精度,真空,无磁性,无油润滑强酸,强碱等特殊环境下工作,这些新的要求仅仅依靠对传统的金属轴承改进结构可改善润滑条件已经远远不能满足,必须开发新型材料,从根本上进行突破和创新才行,国内外研究发现某些陶瓷材料具有优异的性能,可以承受金属材料和高分子材料难以胜任的严酷的工作环境,并且又具有轴承材料所要求的全部重要特性,因此将陶瓷材料应用于轴承制造,已成为世界高新技术开发与应用的热点,成为机械工作材料技术革命的标志。     

沉痛悼念于长敏教授

于长敏教授的离去我很痛心,他是我交往的高等学府中受人尊敬的教授,他不仅品德高尚,才华出众,更能仗义执言,不卑不亢,既是位有前途的教授,又是位支持正义,维护弱者的学者。我是位自学者,只有初中学历,在艺术界,与那些大学教授,博导们,自愧不如,总是在谨言慎行,也难免受到那些所谓学者们的冷眼。唯有于教授与我谈的深刻,交往融恰,以心交心,触动难忘。他看得起自学者,尊重我的艺术,时常仗义立挺我的人和作品。尽管他比我小十余岁,他的品德和宽宏的心胸,始终是高大的,让人起敬。     

橡胶的填充剂

橡胶制品的物理性质,大有依赖于所加填充剂的品质与数量,而物理性质则是主要决定橡胶制品的用途的。物理性质是有多种多样的,如下列所举:抗张强度,拉力系数,硬度,伸长度,比重,对撕擦及弯扭的抵抗力,永久应变,可燃度,热传导度,电性,对(?)气、溶剂、化学药品的抵抗力,老化,     

新型功能玻璃

玻璃在日常生活中随处可见,从建筑玻璃,器皿玻璃,到玻璃镜片等可以说与人们的生活息息相关,从不同的方面满足生活和生产的需要,随着科学技术的发展和社会的进步,人们对玻璃的要求越来越趋于多样化,功能化,所谓功能化是指通过改变其化学成分或采取适当的工艺和加工方法,将一定的物理性质,化学性质,生物学性质等赋予玻璃体,使其获得所需的功能,可以把功能化与玻璃体之间的关系比作人的神经系统与骨骼,功能化的玻璃作为一个有机整体,能够更好地服务于人类,近些年来,功能玻璃的研究一直非常活跃,从玻璃的化学成分上说,除氧化物玻璃外,还有卤化物玻璃,硫属化物玻璃,金属玻璃等;从形状上说,有块（片）状玻璃,纤维玻璃,镀膜玻璃,微粉末等多种根据用途而制出的功能玻璃,加工或制造方法,除传统的熔融一冷却法和设计新成分外,还有镀膜法,结晶法,离子交换法,溶胶－凝胶法等,如此众多的功能玻璃按其功能或主要使用性能来分类的话,可大致分为七类。     

钻井队成本控制现状及主要途径分析

随着经济的发展,社会的进步,国家发展战略的需要,对于能源的需求增加。能源消费的快速增长,为世界能源市场创造了广阔的发展空间。近几年,我国追求能源的可持续发展,纷纷对石油,天然气,地下水等资源合理利用,这就需要钻井队的帮助。钻井工程生产规模大,生产成本高,投入多,需要的人力物力多,风险大,所以一方面为了国家能源的需要积极开发能源价值,另一方面为了节省成本,对钻井队成本进行控制,以追求成本低,产量大的目标。本文将从钻井成本控制的现状,与国外相比我国现在钻井成本高的原因,钻井队成本控制的主要途径,如何解决成本问题进行探讨。     

谈谈陶瓷工笔人物画

陶瓷工笔人物画是陶瓷技术的进步和发展的基础上发展起来的.尤其是在最近几年,中国的陶瓷工笔人物画的绘画材料,创作手法和题材,已经有了很大的发展和创新,给人以新的审美经验.陶瓷工笔人物装饰,顾名思义是笔工整,细致,丰富多彩的陶瓷肖像人物.陶瓷工笔人物画是在我国历史悠久,历史悠久的传统工笔人物画的基础上开发的其在中国工笔人物画的发展经历了一个漫长的过程,到了清代已经完全成熟,不仅是一个广泛的主题,精美的绘画,蓝色和白色,色彩鲜艳,品种齐全,斗彩,珐琅,柔和的.可分为各种美女画像,神话中的人物,戏剧人物,有意义的人物,历史人物,儿童等.由于不同的地域不同的地理和文化的选择,势必会产生合适的艺术表现形式,这是时代的需求,以满足当代人的审美需求与当代文化语境下的独特性.     

液滴撞击微结构疏水表面的动态特性

对去离子水滴撞击不同几何尺寸显微结构方柱和方孔状疏水表面的动态特性进行了研究。结果表明：当液滴以不同速度撞击微方柱疏水表面时,液滴展现铺展和回缩过程,且随着韦伯数（We数）增大,最大铺展直径增大,并伴随卫星液滴出现,但到达最大铺展直径的时间一致;而当液滴以相同的速度（We数相同）撞击间距不同的微方柱疏水表面时,液滴的最大铺展直径随着间距的增大而减小,且铺展过程会液滴浸润状态变得不稳定,发生由Cassie向Wenzel状态的浸润转变。当微方柱间距较小时,液滴受到的黏附功越小,越易发生向Cassie状态的转变;液滴撞击微方孔疏水表面时,液滴以规则的圆环状向外铺展和回缩,最后呈现近似规则的椭球状,不会发生向Wenzel状态的浸润转变,利用建立的物理模型对前述现象进行了分析。     

废钢在底吹反应器中运动熔化及混匀的水模型实验

通过水模型实验,使用饱和氯化钾溶液制作的冰样模拟重型废钢,研究其在底吹气体搅拌反应器中的运动、融化及溶质的混匀规律。探究了单孔吹气模式下的液面高度、双孔吹气方式下的气体流量等因素对其的影响。结果表明,单孔吹气时,液面高度较低时(液面高度与直径比为0.42),气柱发展不充分,容器内环流较弱,盐球在气柱上下往复运动,融化较为缓慢。随着液面高度增加(液面高度与直径比为1.04),盐球随着环流运动,融化过程加快,按照98%标准得到的KCl的混匀时间甚至低于融化时间。双孔吹气时,A孔气体流量0.8 m3/h不变,B孔气体流量为0.5和1.0 m3/h时,盐球从吹气孔A上方加入后,在容器底部停留一段时间,在60~70 s之后才运动到顶部,沿着环流运动;B孔流量增加至1.5 m3/h时,盐球不会在底部停留,随气柱运动到吹气流量大的一侧的羽流区,其融化过程较快。在双孔吹气方案中,也发现了KCl的混匀时间低于融化时间的规律,这和融化末期盐球质量较小,释放的盐分较少有关。在本研究中,双孔吹气对盐球融化的促进作用不如单孔吹气且流量较大的方案。     

Effect of the sol fraction and hydrostatic deformation on the viscoelastic behavior of prestrained highly filled elastomers

This study focuses on the relations between the microstructure and the viscoelastic behavior of an industrial solid propellant belonging to the class of highly filled elastomers. Precisely, the study aims at determining the impact on the viscoelastic behavior of the presence of the sol fraction inside the polymer network. The sol fraction is the part of the binder that a good solvent can extract. The solid propellant is swollen to various extents by solutions of plasticizer and polymer molecules. This swelling leads to a hydrostatic deformation of the polymer network, corresponding to an extension or contraction loading for each specimen. Prestrained dynamic mechanical analysis tests, superimposing a small oscillating strain on a prestrain, characterize the viscoelastic behavior. The degree of swelling of the network and the effective filler fraction drive the viscoelastic response. In addition, the mechanical behavior does not depend on the chemical nature of the introduced sol fraction. Moreover, a nonlinear behavior, i.e., an increase in both storage and loss moduli with increasing prestrain, is initiated at low prestrain. This nonlinearity depends on the contraction or extension of the network and could result from particles aligning with prestrain, which is expected in such highly filled materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Lipid soil removal from cotton fabric after mercerization and carboxymethylation finishing

Soiling and soil removal from cotton fabrics that had been chemically modified by mercerization and carboxymethylation were studied using electron microscopy and radiotracer techniques. The distribution of lard soil in specimens before and after laudering was determined by means of chemical tagging with osmium tetroxide. Both the chemical and physical changes of the cotton resulted in differences in soiling and soil removal of lipid soil. Mercerization and carboxymethylation of cotton swell the cotton fiber, decrease the crenulation and the lumen, and smooth the fiber surface. These finishes also increase the pore volume and thus the chemical accessibility of the fibrillar structure. In addition, carboxymethylation causes changes in the chemistry of the fiber by increasing the carboxyl group content. These structural changes reduce the amount of soil deposited in the lumen of the fiber, particularly for the carboxymethylated cotton. They also increase soil removal from the crenulation and the interfiber spaces in the yarn bundle. Soil removal from fiber surfaces and from within the fiber—both lumen and secondary wall—was highest for the carboxymethylated cotton, and mercerization also enhanced lipid soil removal. The results of this experiment indicate that chemical accessibility and hydrophilicity of the fiber structure influence both soil deposition and soil removal of lipid soils. Soil removal of these modified cottons is enhanced by multiple mechanisms: (i) the decrease in small crevices and the crenulation or small capillary along the fiber, (ii) the increase in pore volume that enhances chemical accessibility and thus detergency within the fiber structure, (iii) the increase in hydrophilicity that enhances soil removal from the surface by the roll-up mechanism, (iv) the increase of mechanical action due to enhanced swelling of the carboxymethylated cotton, and (v) the reduction of soil redeposition on carboxymethylated surfaces.     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

聚电解质静电沉积改性制备高性能反渗透膜

利用次氯酸钠溶液对商品反渗透膜表面进行氯化处理,然后将聚阳离子电解质壳聚糖通过静电吸附作用沉积在RO膜的表面,系统地研究了氯化过程的pH、氯化时间、次氯酸钠浓度、壳聚糖浓度及其沉积时间对膜性能的影响,以制备出高通量、高截留率的RO膜。在压力1.55 MPa、原料液温度（298±1）K的条件下,测定RO膜处理2000 μg·g^-1氯化钠溶液的水通量和截留率。结果表明,当pH=9、氯化时间为30 min、次氯酸钠浓度为1000 mg·L^-1时,水通量较原膜提高了约19.89%,截留率略有提高;当壳聚糖浓度为0.1%（质量分数）、沉积时间为30 min时,改性膜的接触角降低到34.88°,亲水性提高,水通量较氯化后的RO膜几乎保持不变,为60.55 L·m^-2·h^-1,截留率达到了99.56%。经过氯化和沉积改性后的RO膜水通量和截留率均得到了提高。     

Calculation of Residual Thermal Stresses in Injection Molded Amorphous Polymers by the Finite Element Method

Abstract

The finite element method (FEM) is used to calculate the distribution of residual internal stresses in an injection molded plate-shaped polystyrene specimen. The first step of the calculating procedure is the determination of the temperature distributions in the plate and its variation with cooling time. The temperature distribution data are then used for the determination of the corresponding stress distribution. Also this latter step is accomplished using the FEM-technique. The residual stress distribution is obtained when the sample has been cooled to the temperature of the mold. The main result of the calculations is the finding that the surface layer of the plate is subject to compressive stresses, while the interior accommodates stresses of tensile type. The calculations relate to a polystyrene specimen. The results are shown to agree well with earlier data concerning internal stresses in injection molded objects. The possible influence of anisotropy and visco-elastic relaxation has been neglected. The method can be applied to other amorphous polymers and, after a slight modification, also to polymers of semicrystalline type.     

Écoulement de Taylor‐Couette en géométrie finie et à surface libre

The reactors of Taylor‐Couette type are relatively recent application in the engineering processes field. The stability and the flow structure in this device are examined under the effect combined of the free surface and the fluid's height in annular space. The exploitation of the flow regimes is carried out according to the number of Taylor for various values of aspect ration Γ. By means of ultrasonic velocimetry (UPV) we determine axial average velocity profile and the axial wavelength. We also carry out the spectral analysis by Fourier's fast transform of the fluctuations associated with the average velocity values in order to analyze the flow structure. We particularly aim for checking the presence or the absence of the azimuth wave according to the filling height and the rotational velocity imposed. We highlight the effects of free surface and aspect ratio on the conditions of appearance of the second instability ( wavy mode). The analysis of the fluctuation shows that the appearance of the azimuth wave regime (Wavy mode) is delayed when the aspect ration decreases. Below a critical value noted Γc = 10, the azimuth wave regime is not observed any more.     

Pd-Pb/SiO2催化高浓度乙烯基乙炔加氢合成丁二烯

研究了硅胶负载钯铅双金属催化剂催化高浓度乙烯基乙炔加氢合成丁二烯过程。结果表明,加入适量的铅可起到分隔钯纳米粒子,阻碍钯纳米粒子团聚的作用,从而提高催化剂的催化活性,最佳Pb/Pd摩尔比为0.2。继续提高Pb/Pd摩尔比时,会生成铅钯合金相,造成催化剂活性降低。X射线光电子能谱结果表明,催化剂的催化活性与Pd 3d的电子结合能呈正相关关系。制备催化剂过程中,还原温度对催化剂的结构和催化性能影响显著。在350℃下还原得到的催化剂中金属氧化物还原不彻底,催化剂活性较低;还原温度为450℃时,则会引起钯纳米粒子烧结,造成催化剂的催化活性和对丁二烯的选择性同时降低;催化剂的最佳还原温度为400℃。在40℃催化乙烯基乙炔反应40 h后,积炭造成催化剂的孔道堵塞,催化剂失活。因此,需要进一步开展改善催化剂的抗积炭能力和使用寿命方面的研究。     

Selective Sequestration of Pyrrolizidine Alkaloids from Diverse Host Plants by Longitarsus Flea Beetles

In 11 species of the flea beetle genus Longitarsus we investigated whether the insects sequester the pyrrolizidine alkaloids (PAs) present in their host plants of the families Asteraceae and Boraginaceae. In all cases where PAs could be detected in the leaves of the local host plant, they could also be detected in the corresponding beetles. In one host plant, Pulmonaria officinalis, no PAs could be detected in the leaves, yet were present in the beetles collected from them. We suggest this is due to uptake of PAs during the root-feeding larval stage. By comparing the GC-MS pattern of PAs found in the beetles with those of their hosts, we investigated the specificity of this sequestration. Furthermore, we compared the pattern of sequestered PAs across beetle species that had been feeding on the same plant, and across hosts in Longitarsus species that feed on different plants in the field. This allowed us to analyze to what extent the PA pattern in the insects is specific for the beetle species and depends on the local food plant. Our data indicate that the PAs found in the beetles are largely determined by the host plant, e.g., whether alkaloids typical of the Boraginaceae or Asteraceae are present. However, there are some indications for a selective uptake of PAs and apparently the beetles are able to metabolize them.