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。     

对宜兴紫砂传统壶创新的认识

宜兴紫砂,始于宋,盛于明,兴于清,历经传统与创新,以其细腻精湛的工艺,方圆不一的形态,千姿百态的造型,广为古今中外文人雅士的钟爱。近年来,继承传统,立足创新,紫砂收藏热一浪高过一浪,随着茶艺的盛行,经济的发展,紫砂收藏揭开了新的篇章。     

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.     

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,     

有多少人,一辈子在单位里挣扎

正也许这篇文章,太过残酷,穷尽了世相人生。而现实的生活,往往如此,惊心动魄。单位,就是这么一个方正的盒子。一辈子的悲喜,一辈子的荣辱,一辈子的平淡与激荡,写满四壁:楷体的付出,草书的纠结,以及,宋体的庸常。没有谁,是为单位而生的,但多少人,却要在单位里终老。是的,一辈子的光阴,实实在在地扔在了单位里头。无论来的时候曾经多么光鲜亮丽,单位最终还给你的,不是一个头发花白的老头子,就是一个皱纹纵横的老太太。     

心爱陶瓷

正在景德镇,在这个地球上,有很多人一辈子和陶瓷结缘,他们中有的是陶瓷世家至爱,有的是静心的爱,其中也有疯狂的爱。因为,陶瓷是有生命力、磁场力和征服力的。摩羯是最理性的星座,他是十二星座中的王者,是理智和决断的象征。有人说,爱上陶瓷的人一般都是摩羯星座之人,总是会很疯狂地痴迷陶瓷,或许是情,或许是其他的东西,然后,疯狂过后,他们沉稳,变成真理的王者。在景德镇,多少人的一辈子,总是那样坚持、痴迷、疯狂地爱陶瓷,恋陶瓷,背弃世俗,背弃自己,背弃所处的生存世界,只是为了心爱的陶瓷,哪怕在它不完美的时候。     

定窑拉坯技艺浅析

<正>定窑,始于唐,兴于宋,失于元,宋代五大官窑(定,汝,官,哥,钧)之一,属白瓷。上世纪七十年代,在周恩来总理的关怀下,在以陈文增、蔺占献、和焕为代表的新一代定瓷人的艰苦奋斗下,定瓷得以恢复与发展。近千年的创造,变革,开拓,定窑拥有了非凡的气魄及熟稔的工艺技艺,其冲破樊篱,独树一帜。定窑传统工艺—拉坯,在整个定窑的发展中,是核心技艺存在,呈现的形、神,诠释着定窑所传递给我们的时代之美!勤劳的陶工,亦是通过对拉坯技艺的认识、理解,感受拉坯的艺术性,表达对美的     

一种废弃塑料的分类设备

本实用新型提供一种废弃塑料的分类设备,包括分离主体,皮带轮,皮带,座板,电机,支撑架,伸缩皮带机,电器控制箱,保护架,分离出口,分离通道,杂物通道,放置箱,分离探测器和机械手,所述的皮带轮设置在分离主体的上部内侧两端;所述的皮带通过皮带轮连接在皮带轮的外部;所述的座板设置在分离主体的左侧;所述的电机设置在座板的上部;     

集气站建设中的质量控制

在集气站的建设过程中,由于技术、经济、管理登方面的原因,会导致一些问题的出现,这些问题不仅影响着集气站的建设进度,同时会对集气站的建设起到连带反应,影响着后期的建设,而且集气站的质量问题,是整个运营的重要问题,如果集气站出现了问题,会产生严重的事故,造成人员伤害,经济损失。因此,在集气站建设中,抓紧质量控制,运用科学的方法,合理管理,严格监督,对整个建设起到重要作用。     

研究山区公路路线设计

山区修建公路和平原相比,难度要大的多,山区的地形和地质都比较复杂,要想在山区修建公路,首先要经过仔细的研究,对山区的地形要熟悉掌握,根据山区的特征,合理的设计公路的路线,公路的路线设计要合理科学,优秀的设计是公路建设的基础,因此,设计人员要认真的对待路线的设计工作,降低施工难度,控制工程投资,确保工程质量,保证公路运营安全,提高公路使用价值。     

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。     

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.     

Trapping the western pine beetle at and near a source of synthetic attractive pheromone Effects of trap size and position

Western pine beetles were caught on unbaited sticky traps placed near a source ofexo-brevicomin, frontalin, and myrcene. Size of trap, distance and direction from the source of attractant, and height from the ground were varied. Significant differences in trap catch were observed in relation to each of the variables. Traps close to the source of attractant caught more beetles than traps farther from the source. Traps downwind of the source of attractant caught more beetles than did upwind traps. More males than females were trapped close to the source of attractant.Based in part on a thesis submitted by the senior author to the University of California, Berkeley, California, in partial fulfillment of the requirements for the degree Master of Science in entomology, December 1976. These studies were supported by the U.S. Forest Service and in part by the Rockefeller Foundation and a joint grant (NSF GB-34718/BMS 75-04223) from the U.S. National Science Foundation and the U.S. Environmental Protection Agency to the University of California. The findings, opinions, and recommendations are not necessarily those of the University of California or the funding agencies.Trade names and commercial enterprises or products are mentioned solely for information and do not constitute endorsement by the U.S. Department of Agriculture or University of California.     

一种自适应柱状密封气膜特性分析

提出一种自适应柱状气膜密封,构建气膜-密封环为研究对象,考虑了偏心间隙发散问题,并定义Rayleigh台阶对气膜周期的突变性,建立了气膜雷诺方程和膜厚变化函数关系式的动力润滑数值模型,获得了摩擦副气膜润滑特性,研究结果表明：气膜力随转速和压力升高而增加,泄漏量随压力升高而增加但是随转速增加而下降,说明密封内部压力流占主导地位。随后,利用曲面槽型雕刻技术,结合高速试验台对密封进行测试,结果表明：理论计算模型与试验结果吻合度较高,斜槽区域存在更多擦痕与磨损,说明斜槽浮动性弱于直列槽;但斜槽的切向流动小于直列槽,导致斜槽泄漏量小于直列槽。该研究成果为自适应柱状气膜密封的气体流动规律和应用提供了理论基础。     

Kinetics of organic solvent-soluble and native lipase

Organic solvent-soluble lipase was prepared with a synthetic detergent. The solvent-soluble lipase was presumed to be a complex of the enzyme and the detergent. To investigate the effect of the detergent attachment to the enzyme on the reaction properties, the kinetics of the solvent-soluble lipase and of the native lipase were estimated by using glycerides in a homogeneous solution of buffer and tetrahydrofuran. Analysis of the direct interaction between the enzyme and the substrate could serve to characterize the steric structure around the active site of the lipase. The K_m values also differentiated the solvent-soluble lipase from the native lipase. These findings show for the first time that the detergent surrounding the enzyme molecule may affect not only the solubility of the enzyme, but its kinetics as well.     

Lipid distribution on textiles in relation to washing with lipases

Effectiveness of lipase in detergency was studied using three test soils (lard, artificial sebum, and olive oil) on a woven cotton fabric. Distribution of oily soil on fabrics was determined for three different treatments (unwashed, washed with detergent without lipase, and washed with detergent plus lipase). Osmium tetroxide was used to label lipid soil for analysis in the scanning electron microscope. Both longitudinal and cross-sectional backscattered electron images for unwashed samples showed that soil was present on surfaces of the cotton fibers and in interfiber spaces of the yarn bundle. Lard soiled samples had large deposits on the fabric surfaces, while artificial sebum and olive oil appeared more uniformly distributed throughout the textile. Oil was deposited in the interfiber capillaries of the yarn bundle and in the crenulation, secondary walls, and lumen of the fibers. Energy dispersive X-ray microanalysis was used to determine relative concentrations of oil at selected morphological locations within the fiber structure and at the fiber surface. Soil distributions within the fibrous structures differed with type of soil and laundry treatment. Backscattered electron images dramatically demonstrated the effect of lipase on cleaning. After washing with detergent plus lipase, yarn surfaces had much less residual soil; residual soil that remained was in the irregularities of the cotton fiber surfaces. Concentrations of oil in the secondary walls, crenulations, lumen, and the fiber surfaces were lower after lipase treatment for all three soils. While washing with detergent removed soil from the yarn and fiber surfaces and the crenulation of the cotton fiber, only the samples washed with detergent plus lipase had lower concentrations of soils within the secondary wall and lumen of the cotton fibers. Fabrics soiled with olive oil and washed with detergent plus lipase had the lowest concentrations of residual soil across the textile structure; the residual soil observed was mainly in the irregularities on the fiber surfaces.     

煤油贮箱冷氦鼓泡增压过程数值研究

火箭飞行过程中,约90 K的低温氦气用以加压室温下的煤油贮箱使煤油流出,保障发动机燃料供应。为尽可能减少氦气用量,设计低温氦气从液相中喷入,使得氦气在贮箱内上升过程先和液态煤油充分换热升温,再进入气相空间增压。但该过程可能引起两个不利的结果,首先浸没在煤油中的低温氦气管路表面可能结冰,结冰沉底或可能堵塞发动机滤网;其次氦气可能被煤油携带,从而排出口位置可能出现气液两相流。这两种情况都对火箭发动机稳定运行造成负面影响,因此是不允许的。对低温氦气在贮箱中心喷入和环向多孔喷入两种结构的气液两相流过程进行了数值研究,构建了基于Euler-Euler模型的两相传热非稳态模型,数值结果与地面实验观察到的现象进行了定性对比,定性验证了模型的准确性。重点考察了煤油排出过程两种喷入结构的气液两相流分布以及煤油结冰可能性。研究结果从机理上解释了实验现象,并为煤油贮箱增压排出方案设计提供了参考。     

Modified dynamic matrix control

DMC (Dynamic Matrix Control) has been used successfully in industry for the last decade. It can deal with constraints and unusual dynamic behavior directly. It also shows a good control performance for the servo problem. Relatively, it can’t reject disturbances systematically. We propose a modified DMC method to control the regulatory process more efficiently. The proposed DMC method makes the control output by subtracting the estimated disturbance from the control output of the original DMC. Here, the disturbance is estimated by a new disturbance estimator. It shows better control performances than the original DMC.     

Analyse Expérimentale et Numérique du Comportement de Membranes Thermoplastiques en ABS et en HIPS dans le Procédé de Thermoformage

In this work, we are interested, on the one hand in the characterization of circular polymeric ABS and HIPS membrane under biaxial deformation using the bubble inflation technique, on the other hand in modelling and numerical simulation of the thermoforming of ABS and HIPS materials using the dynamic finite element method. Hyperelastic models (Mooney‐Rivlin, Ogden) are considered. First, the governing equations for the inflation of a flat circular membrane are solved using a variable‐step‐size‐finite difference method and a modified Levenberg‐Marquardt algorithm to minimize the difference between the calculated and measured inflation pressure. This will determine the material constants embedded within the models used. For numerical simulation, the lagrangian formulation together with the assumption of the membrane theory is used. Moreover, the influence of the hyperalastic model on the thickness and on the stress distribution in the thermoforming sheet are analysed for ABS and HIPS materials.     

回灌过程中离子强度和水流流速对胶体粒子在多孔介质中堵塞的影响

人工回灌过程中的堵塞问题一直是影响其推广的瓶颈,目前回灌过程中大颗粒悬浮物导致的堵塞机理研究较多,对胶体类颗粒物的堵塞机理研究相对少。采用室内砂柱实验,研究不同离子强度和不同水流流速条件下胶体在饱和多孔介质中的迁移-滞留特征。选择大肠杆菌为实验胶体,设计在不同离子强度、不同水流条件下的砂柱回灌实验;运用Hydrus-1D软件模拟,拟合穿透曲线后得到表征胶体沉积的相关参数。实验结果表明,在相同的离子强度下,流速增大会促进胶体的迁移,穿透曲线峰值增高,胶体的吸附率减小。在中等离子强度条件下（IS=30、50 mmol·L^-1）流速对胶体的这种影响比在更低的离子强度（≤10 mmol·L^-1）或更高的离子强度（≥300 mmol·L^-1）条件下更为显著;相反地,同一流速条件下,离子强度从10 mmol·L^-1升高到300 mmol·L^-1时,胶体的吸附随着离子强度的增加而迅速增加。从胶体和介质相互作用势能来看,随着离子强度的增加,胶体和砂表面的相互作用增强,有利于胶体吸附在介质表面,增加介质堵塞的概率。但是,在一定的离子强度下,流速的增加产生的水动力剪切力有利于促进胶体的迁移,不利于胶体的吸附或阻塞,减少了微小颗粒堵塞的概率。模拟结果显示吸附速率系数k、最大固相沉积量S_max随着离子强度的增大而增大,随着流速的增大而减小。从整体上来看,回灌过程中胶体微粒的迁移滞留行为主要受控于离子强度,但水流因素会干扰离子强度的控制作用。在实际的人工回灌过程中,有效的预防堵塞需要将化学（降低离子强度）和水动力（增加回灌水流速）手段有效地结合起来。