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1.
通过对SOCl2/TiCl4引发体系的α-蒎烯(M1)/苯乙烯(M2)共聚产物进行GPC、1HNMR以及微臭氧化-薄层层析法等分析表征,证明该引发体系能在宽广的单体投料比范围内实现有效共聚。在确认仅生成共聚物的反应条件下,采用Mayo-Lewis式积分法测得该体系在-30℃、[SOCl2]=20mmol/L、[TiCl4]=60mmol/L、CH2Cl2溶剂中的竞聚率分别为苯乙烯r2=2.31±0.15;α-蒎烯r1=0.52±0.06。  相似文献   

2.
2-丁烯酸异丁酯阴离子聚合条件的研究   总被引:2,自引:0,他引:2  
探讨了引发剂结构、添加盐(LiBr)、聚合温度对2-丁烯醚异丁酯阴离子聚合的影响。实验结果发现,使用立体阻碍作用大的1,1'-二苯基己基锂作引发剂,在与其等摩尔量的LiBr存在下,于-40℃聚合,为SBC的最佳聚合条件。另外,通过DSC及特性粘度的测定,得到聚2-T烯酸异丁酯的Tg=445℃,[η]=KMα中的α=0.77。  相似文献   

3.
甲基丙烯酸酯嵌段共聚物的合成与表征   总被引:2,自引:0,他引:2  
研究了MMA和C7~9MA的阴离子共聚合,得到了A-B型嵌段共聚物。讨论了嵌段顺序、温度、引发剂及PC7~9MA-活性链长对MMA嵌段共聚的影响,认为,当第一嵌段单体为C7~9MA,T=-20℃,[I]=5.0~5.4×10-2mol/L,Mn(PC7~9MA-)<1.6×104时,有利于PC7~9MA-b-PMMA嵌段共聚物的合成;采用GPC、IR、NMR对所得嵌段共聚物进行了表征。  相似文献   

4.
Fe(OH)3中微量金属离子对水热合成α—Fe2O3粒径的影响   总被引:3,自引:0,他引:3  
郑学忠  刘晓林 《功能材料》1997,28(6):607-608
本文研究了某些金属离子(Al^3+、Mn^2+、Zn^2+、Cr^2+、Ni^2+、Co^2+)Fe(OH)3凝胶经水热法合成的α-Fe2O3微粉颗粒大小的影响。研究结果出现,随着金属离子的浓度在一定范围内(0.010-0.050mol·L^-1)的增加,α-Fe2O3颗粒有减小的趋势。其中加入Co^2+(0.050mol·L^-1)、Mn^2+(0.100mol·L^-1)可以得到粒径为75nm  相似文献   

5.
联用宽分布VDC-MA悬浮共聚物试样的[η]和GPC谱图数据,确定了此共聚物在四氢呋喃溶剂中、30℃下的Mark-Houwink常数:K=2.54×10-2,α=0.6757。进一步研究了单体配比、转化率、引发剂浓度以及聚合温度等因素对于分子量及其分布的影响,并建立了分子量模型。  相似文献   

6.
双噁唑啉化合物对PBT的增粘作用   总被引:1,自引:0,他引:1  
以2.2'-双(2-唑啉)和双(2-唑啉基)苯作扩链剂,用焙融挤出的方法,对聚对苯二甲酸丁二酯(PBT)进行扩链,考察扩链剂的用量、反应时间和反应温度对PBT的特性粘度及端羧基含量(CV)的影响。结果表明,当用2,2'-双(2-唑啉)作扩链剂时,PBT的特性粘度[η]从0.799提高到0.926dL/g,CV降至5eq/10 ̄6g以下;当用双(2- 唑啉基)苯作扩链剂,[η]从0.763增至0.925dL/g,CV降至10eq/10 ̄6g以下,达到了较满意的扩链效果。  相似文献   

7.
黄恒超  沈家瑞 《功能材料》1996,27(4):335-338
研究用二氧化硅负载n-β(氨乙基)-γ(氨丙基)三乙氧基硅烷[NH2(CH2)2NH(CH2)3Si(OEt)3]作为分散颗粒制备的电流变(ER)流体的流变行为。结果发现,流体具有宾汉流体的特点。以硅油为分散介质,含20%(W/V)分散颗粒的流体,不添加任何活化剂,在剪切速率(r)为8.066s-1时,电场强度(E)从0升至1.50kV/mm,表观粘度(ηa)从0.35Pa·s增大到26.5Pa·s。r提高,ηa降低。改变电场强度、分散颗核含量、分散介质种类和添加极性分子,可以改变流体的剪切应力和表观粘度,但不能改变流型。  相似文献   

8.
本报道Nb,Ti微合金钢的热变形动态模拟变形抗力模型。在试验中用热加工模拟试验机进行高温压缩试验,其变形温度为1123-1423K,变形速率为0.1-60s^-1。结果表明,在峰值以前该钢种的流变应力数学模型为:σ=5.99.ε^0.167·ε^(6.47×10^-5·T)·exp(4064/T)。形变激活能(Q)为444kj/mol,0β系数为0.080。峰值应力(σp),临界应变(εc)和…  相似文献   

9.
研究了以span-80为乳化剂和过硫酸钾-脲引发体系下,甲基丙烯酸乙酯基三甲基氯化铵反相乳液聚合的动力学,得出在「K2S2O8」为12.3-73.8μmol.L^-1.「CO(NH2)2」o为0-0.95mmolL^-1,乳化剂为41.75-66.80g.L^-1范围内的聚合速率表达式:Rp^∞「DM.MC」^1.71「K2S2O8」^0.28「CO(NH2)2」^0.01「3」^-1.18,BC  相似文献   

10.
使用多体项展式分析势能函数,研究了O+HO2反应碰撞的经典轨迹,指出存在二个反应通道,即(1)O+HO2→OH+O2和(2)O+HO2→HO2+O。在室温下,求得反应(1)的近似速度常数为(4.1±0.06)×10^-11cm^3·molccule^-1·S^-1,与实验值(5.4±0.9)×10^11符合甚好;反应(2)的速度常数为5.4×10^-13。对反应(1),总能量的72.5%分配于产物  相似文献   

11.
A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.  相似文献   

12.
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……  相似文献   

13.
The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……  相似文献   

14.
Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.  相似文献   

15.
We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.  相似文献   

16.
Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.  相似文献   

17.
ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.  相似文献   

18.
Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.  相似文献   

19.
As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.  相似文献   

20.
TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.  相似文献   

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