聚醚扩链脲增韧环氧树脂/双氰双胺固化体系

以聚醚PPGl000、异氰酸酯、二胺为原料，合成了聚醚扩链脲(EU)，系统考察了EU改性的环氧树脂E一51／双氰双胺(dicy)固化体系的固化反应活性、动态力学行为、冲击性能和断裂面形态结构。并对体系的冲击性能、形态结构与动态力学行为之间的关系进行了探讨。结果表明，改性体系固化反应活性明显提高，固化反应表现活化能降低，固化反应峰顶温度从190℃降低至140℃，固化反应的表现活化能由145．5kJ／mol降至73．6kJ／mol；改性体系冲击强度明显提高，较未改性的E-51／dicy体系提高了9倍，较小分子取代脲改性的E-51／dicy体系提高了7倍；其冲击试样断裂面的形态具有明显的韧性断裂特征。     

Al2O3/环氧树脂-氰酸酯复合材料反应动力学及力学性能

以双酚A型环氧树脂(E51)和双酚A型氰酸酯(BCE)为原料,研究E51改性BCE共固化反应机制。同时,以E51-BCE为基体树脂,溶胶-凝胶法(Sol-Gel)自制Al2O3为增强体,制备Al2O3改性E51-BCE (Al2O3/E51-BCE)复合材料。通过非等温DSC确定了E51-BCE体系的固化工艺及固化反应动力学,并根据Kissinger法和Ozawa法求得体系的表观活化能分别为66.13 kJ/mol和69.46 kJ/mol。利用红外光谱跟踪固化体系在起始固化温度为160℃、 180℃时的反应历程,结果表明:起始固化温度在160℃时,以E51与BCE直接反应为主;起始固化温度在180℃时, BCE反应活性提高,以BCE自聚反应为主,生成三嗪环的速率加快,少量的BCE直接与E51反应生成恶唑啉结构。对Sol-Gel法自制Al2O3进行FTIR和TEM表征,结果表明:Al2O3为短纤维状的晶体,表面含有少量羟基。SEM结果显示:Al2O3为分散相,与基体间界面模糊, Al2O3/E51-BCE复合材料的脆断面裂纹不规则,为典型的韧性断裂;当Al2O3掺杂量为3wt%时, Al2O3在基体中分散均匀, Al2O3/E51-BCE复合材料的冲击强度和弯曲模量分别为24.2 kJ/m2和2.54 GPa,比基体树脂的冲击强度和弯曲模量分别提高53.65%和22.12%,力学性能得到明显改善。     

DOPO-VTS键合改性环氧树脂的制备与性能

以含磷有机硅(DOPO-VTS)作为改性剂对环氧树脂(E51)进行化学接枝改性,制备不同含量的DOPO-VTS键合改性E51。核磁共振氢谱(~1H-NMR)、红外吸收光谱(IR)、环氧当量(EEW)和差式扫描量热法(DSC)的测试结果证明DOPO-VTS成功接枝到E51分子的主链。利用甲基四氢苯酐对改性E51进行固化,考察DOPO-VTS的含量对固化后改性E51力学性能的影响。当E51与DOPO-VTS质量配合比为100∶10时,改性E51的拉伸强度达到最大值为78.18MPa,较未改性E51的63.27MPa提高约23.57%;改性E51的冲击强度为19.86kJ/m~2,较未改性E51的18.15kJ/m~2提高约9.42%。     

双马来酰亚胺改性环氧树脂固化反应行为及性能研究

采用双马来酰亚胺（BMI）改性环氧树脂（TDE-85）／芳香胺（DAMI）固化体系。用差式扫描量热法（DSC）对树脂体系的固化反应行为与固化动力学进行了分析，考察了BMI含量对改性体系性能的影响。结果表明，随着体系中BMI比例的增加，体系固化放热峰向高温区移动，总反应热减小，固化物的耐热性和力学性能明显提高；根据Kissinger方法求得改性前后体系固化反应的表现活化能△E分别为52．46和57．72kJ／mol；根据Crane理论计算得到改性体系的固化反应级数n为0．88，固化反应过程为多级反应。     

环氧封端硅氧烷改性环氧树脂的制备及性能研究

采用环氧封端硅氧烷低聚物为改性剂,通过与双酚A型环氧树脂共混制得改性环氧树脂固化体系。通过测定改性固化物的热学性能、力学性能和原子氧剥蚀性能,并利用扫描电镜对冲击断裂面和原子氧辐照前后表面的形态进行分析,系统探讨了环氧封端硅氧烷低聚物对改性环氧树脂性能的影响。结果表明,采用环氧封端硅氧烷低聚物改性后,固化体系的耐热性、韧性和耐原子氧剥蚀性能均有提高:与未改性环氧树脂相比,改性剂含量30%时,10%热失重温度提高了23℃,弯曲强度、冲击强度分别由82.0kJ/m~2、8.7kJ/m~2提高到93.4kJ/m~2、33.4kJ/m~2,经累积通量1.2×1020 atoms/cm~2原子氧辐照后质量损失仅为未改性环氧树脂的20%。     

二氯二苯基硅烷改性双酚A型环氧树脂性能研究

以二氯二苯基硅烷对双酚A型环氧树脂进行改性,通过拉伸实验、冲击实验、DSC、SEM研究了二氯二苯基硅烷的含量对环氧树脂E-51固化物性能的影响.结果表明:用5.9份的二氯二苯基硅烷改性时,树脂固化物的拉伸强度达到了67.85MPa,断裂伸长率达7.59%,冲击强度达13.38kJ/m2,环氧树脂的玻璃化转变温度达146.56℃.分别比未改性提高了18.9MPa、3.6%、5.5kJ/m2、28℃.     

反应型液晶聚合物改性环氧树脂性能的研究

合成了一种端基含有活性基团的热致性液晶聚合物（LCPU），用其改性环氧树脂CYD－128／4，4‘-二氨基二苯砜（DDS）固化体系，对改性体系的冲击性能，拉伸性能，弹性模量，断裂伸长率，玻璃化转变温度Tg与LCPU含量的关系进行了探讨，对不同种类液晶化合物对CYD－128／DDS体系改性效果进行了比较，用扫描电镜（SEM）对材料断面的形态结构进行了研究，结果表明，LCPU的加入可以使固化体系的冲击强度提高2－3．5倍，拉伸强度提高1．6－1．8倍，弹性模量提高1．1－1．5倍，断裂伸长率提高2－2．6倍，Tg提高36℃－60℃，改性后材料断裂面的形态逐渐呈现韧性断裂特征。     

新型工艺合成的线型苯酚甲醛型环氧树脂的研究

为了提高固化后普通双酚A型环氧树脂的耐热性,采用新型环保工艺合成的线型酚醛树脂(简称SPN)经环氧化制备了线型苯酚甲醛型环氧树脂(简称EPN).比较了甲基四氢邻苯二甲酸酐(MeTHPA)分别固化EPN和普通线型苯酚甲醛型环氧树脂F-51两个体系的固化特性和浇铸体性能.结果表明,由于微观化学结构的差异,EPN体系和F-51体系的反应表观活化能分别为51.4kJ/mol和67.7kJ/mol,即EPN体系的反应活性略高于F-51体系,两体系固化产物的力学性能没有明显差异,EPN体系和F-51体系的玻璃化转变温度分别为415.65K和408.45K,即EPN体系的耐热性略低于F-51体系.     

含金刚烷结构胺类固化剂的制备与性能

以1,3-二溴金刚烷为原料,合成了一种环氧树脂固化剂1,3-二[4-(4-氨基苯氧基)苯基]金刚烷(BAPPA),并采用傅里叶变换红外光谱、核磁共振波谱等对其结构进行了表征,用差示扫描量热分析研究了环氧树脂(E51)/BAPPA体系的固化反应动力学,根据Kissinger方程计算出体系的反应活化能为43.57kJ/mol。对E51/BAPPA固化物的耐湿热性能、动态热机械性能、力学性能、介电性能的表征结果表明,环氧树脂固化物的拉伸强度为98MPa,玻璃化转变温度(Tg)为176.3℃,Td5高达406℃,吸水率、介电常数比相同条件下E51/DDM固化物分别降低了34.9%和15.7%。     

改性双来亚酰亚胺树脂的研究

合成了２，２′－亚甲基－二（４－甲基－６－烯丙基）苯酚，和它增韧二苯甲烷型双马来酰亚胺树脂，对改性双马亚酰亚胺预聚物的凝胶化时间、ＤＳＣ分析和ＦＴ－ＩＲ分析的研究，得到了改性双马亚酰胺树脂体系的固化条件来１８０℃／１ｈ＋２００℃／２ｈ＋２５０℃４／ｈ；热重分析法研究了双马亚酰亚胺树脂体系的热分解反应动力学，得出体系的的热分解反应活化能为２７４．４ｋＪ／ｍｏｌ；改性双马来酰亚胺树脂体系常弯曲强度为１     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

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.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

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

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

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.……     

Deposition and Coating Properties on CVD Tungsten

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.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

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.     

Low-Temperature Properties of Silver

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.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

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.     

Optimum-Simulation von Ernteprozessen

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.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

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.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

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.