DCPD和PET合成不饱和聚酯的研究

探讨了用双环戊二烯和聚对苯二甲酸乙二醇酯废料合成不饱和聚酯树脂的方法：PET用二元醇醇解后，加入顺入烯二酸酐和DCPD，在80－120℃条件下滴加与DCPD等量的水进行反应，反应大约2.5h，加入其它成分，升温酯化直至反应完全。PET一定时，DCPD的含量影响不饱和聚酯同苯乙烯的互溶性和固化过程，DCPD和PET合成的不饱和聚酯树脂与标准树脂相比较，机械性能好，空干性好，解决了环境污染，具有很好的经济效益。     

Structure and properties of CE/CTBN/EP blends: II. Effect of EP on the mechanical properties and thermostability of the CE/CTBN system

Carboxyl‐terminated butadiene‐acrylonitrile rubber (CTBN) has often been used to improve the toughness of cyanate ester (CE) resin while sacrificing modulus and thermostability. In this paper, the addition of the appropriate amount of epoxy resin (EP) to the CE/CTBN system is shown to not only increase the modulus and thermostability of the blend, but also improve the toughness. The values of impact strength showed a maximum for the CE/CTBN/EP 100/5/5 blend. The temperature of 10 % weight loss (T₁₀) improves from 376 °C for CE/CTBN 100/5 to 407 °C for the CE/CTBN/EP 100/5/2.5 blend. It is proposed that addition of the appropriate amount of EP can decrease the mobility and increase the stability of CTBN via the reaction between the terminal carboxyl group of CTBN and the hydroxyl group of EP. But a very high EP concentration will decrease the crosslinking density of CE, consequently reducing the mechanical properties and thermostability of the blends. Copyright © 2004 Society of Chemical Industry     

Shape-control of nano-ZnO by changing the solvent

ZnO sub-micrometer sized disk using ethanol/water mixed solution as solvent is synthesized by solvent-thermal process without any additive, while ZnO nanorods are obtained when water is used as solvent. This formation of disk is discussed based on the reaction of Zn-terminated ZnO (0001) plane with ethanol molecule, which results in the passivation of ZnO (0001) planes and lowering the free surface energy of ZnO (0001).     

Effect of processing history on the properties of Ag-based tapes

The Bi-system tapes and coils were prepared by the powder-in-tube method. The effect of processing and heat treatment on the properties of the tapes and coils was studied. It is found that the shearing stress produced by the rolling process may destroy the 2223 phase, and the destroyed 2223 phase cannot be recovered by heat treatment, whereas the pressing stress produced by the uniaxial pressing process only makes the 2223 phase grains break, and the broken 2223 phase can be closed by the heat treatment. TheJ _c values of the rolling samples, pressing sample, and the coil with a diameter of 35 mm are over 1.3×10⁴, 2.5×10⁴, and 4×10³ A/cm² (77 K, 0 T), respectively.     

落实职教战略地位走创新发展之路

大力发展职业教育是我国教育发展的战略重点。落实职教的战略地位必须走创新发展的道路，树立服务的意识和经营的观念；根据经济社会发展需求形成培养的特色和优势；加强合作，实现国际化和规模化，创新学校管理，深化教育教学改革。     

NdBO_3和 Nd(BO_2)_3的标准生成自由能

用 CaF_2单晶和 ZrO_2(+MgO)为固体电解质分别构成原电池:■和 Pt,B_((s)),NdBO_(3(s)),Nd(BO_2)_(3(s))|ZrO_2|Cr_2O_(3(s)),Cr_((s)),Pt联合测了 NdBO_3和 Nd(BO_2)_3的标准生成自由能:ΔG~0_(NdBO_3)=-1757+3.8×10~(-1)TΔG~0_(Nd)(BO_2)_3=-3435+8.8×10~(-1)T由此求出由氧化物生成 NdBO_3及 Nd((BO_2)_3)的反应的标准生成自由能变化:1/2Nd_2O_(3(s))+1/2B_2O_(3■)=NdBO_(3(s))ΔG~0_(NdBO_3)=-242+1.4×10~(-1)T和 1/2Nd_2O_(3(s))+3/2B_2O_(3(s))=Nd(BO_2)_(3■)ΔG~0′_(NdBO_2)3=-693+4.6×10~(-1)T     

浅谈学校思想政治工作的任务

学校思想政治工作的任务是什么?面对这个问题,不少从事学校思想政治工作的人回答不上来.有些同志虽能说出一些,但仍不免失之肤浅或偏颇.如有的同志认为,学校思想政治工作的任务是政治学习、舆论宣传、说服教育、号召动员等.其实,这些都是思想政治工作方面的具体工作,而非主要任务.这就像学生管理的具体工作是抓纪律、抓卫生、抓内务、抓活动……而其主要任务则是培养学生优秀的思想品质、严格的组织性纪律性和良好的工作、学习、生活习惯一样.我们在实际工作中,是着眼于做好某项具体工作,还是放眼于任务的圆满完成?这是一个工作境界问题.境界越高,对问题的认识越准,工作的措施越对,收到的效果就越好.我们的思想政治工作倘若仅仅是为了做好某项具体工作的话,那就很难达到应有的水平,因为它缺乏必要的宏观目标的指导.你想把握学校思想政治工作的主动权吗?你想把它开展得游刃有余、卓有成效吗?那就首先需要对学校思想政治工作的任务有一个清醒的认识.现结合自己多年从事学校思想政治工作的实践体会,谈一点粗浅的认识.我们认为,学校思想政治工作有思想政治工作的共性,也有学校工作的特点,其任务可以概括为六个字:提高、落实、统一.     

微酸性光亮锡铅合金镀液分析方法

提出锡铅合金液中Ｓｎ＾２＋，Ｓｎ（ＩＶ），ＰＢ＾２＋、ＥＤＴＱＡ、柠檬酸三钠的分析方法。