两种嵌段共聚酯的合成与性能比较

对比研究了聚对苯二甲酸乙二酯－聚己二酸乙二酯（ＰＥＴＡ）和聚对苯二甲酸乙二酯－聚乙二醇（ＰＥＥ）两种嵌段共聚酯的合成与性能。实验结果指出，ＰＥＴＡ的缩聚反应速度比ＰＥＥ的快，ＰＥＴＡ的玻璃化温度（Ｔｇ）高于ＰＥＥ，熔点（Ｔｍ）低于ＰＥＥ．ＰＥＴＡ的结晶速度比速度比ＰＥＥ慢，而且ＰＥＴＡ各个品面的晶粒尺寸大于ＰＥＥ；ＰＥＴＡ的染色性能明显地比ＰＥＥ差，但ＰＥＴＡ的热稳定性明显优于ＰＥＥ．     

EDTA标准溶液固定浓度的配制

ＥＤＴＡ标准溶液固定浓度的配制陈远任，袁青新疆阿克苏第八地质大队（８４３０００）ＥＤＴＡ是化验室中常用的标准试剂，水泥主、熟料及原料中的铁、铝、钙、镁的测定都用ＥＤＴＡ标准溶液滴定。然而只有基准ＥＤＴＡ才能直接配制不经标定就使用，但基准ＥＤＴＡ价洛太...     

紫外分光光度法测定EGS回用下的PTA／EG浆料摩尔比

假定酸值仅为ＰＴＡ的贡献，从而通过测定酸值计算ＰＴＡ／ＥＧ浆料中ＰＴＡ含量的方法，在ＥＧＳ回用下面临ＥＧＳ酸值高，ＥＧＳ预聚物干扰的困难。利用苯系化合物的特征吸收直接定量ＰＴＡ含量，具有抗干扰、操作简便、准确度高的优点，可有效地指导生产     

三乙烯四胺吸收CO2的初探

在常压下，采用搅拌式反应器对ＴＥＴＡ（三乙烯四胺）水溶液吸收ＣＯ２进行了研究，测定了不同温度下，不同浓度的ＴＥＴＡ的ＣＯ２吸收情况，并与常用醇胺吸收剂ＭＥＡ（一乙醇胺）、ＤＥＡ（二乙醇胺）、ＴＥＡ（三乙醇胺）的吸收效果作了比较，同时观察了ＴＥＴＡ－胺－水多元体系对ＣＯ２的吸收情况，得出最佳配比。有关ＴＥＴＡ吸收ＣＯ２研究尚无报道。     

置换螯合滴定在测定锌白粉及玻璃中氧化锌的应用

在含有锌离子及其他多种金属离子的溶液中，加入过量的ＥＤＴＡ溶液，调节溶液的ｐＨ值，使所有金属离子与ＥＤＴＡ定量螯合，然后加入邻菲谵啉置换剂，选择性地定量置换Ｚｎ－ＥＤＴＡ螯合物中的ＥＤＴＡ，从而间接得到试样中氧化锌的含量。此法选择性好，操作简便快速，具有良好的准确度和精密度。     

用中纯度对苯二甲酸生产纤维级聚酯切片

调查了国内使用ＭＴＡ生产ＰＥＴ及纺丝的情况，对用ＭＴＡ生产ＰＥＴ进行了一定理论分析，探讨了降低二甘醇含量和抑制切片黄色的措施。重点介绍了使用钟纺设备ＭＴＡ法生产ＰＥＴ的生产技术。     

PE／EVA／TAIC共混体系中的TAIC的辐射转化反应研究

研究了多官能团单体三烯丙基异氰脲酸酯（ＴＡＩＣ）在ＰＥ／ＥＶＡ／ＴＡＩＣ共混体系中的辐射转化反应，结果表明，当辐射剂量的５．２４ＫＧｙ时，一部分ＡＩＣ在γ射线作用下开始转化反应，随辐照剂量的增加，ＴＡＩＣ的转化率增大，ＥＶＡ的加入降低了ＴＡＩＣ的辐射转化反应速度，当辐照剂量为１５０ＫＧＹ时，ＴＡＩＯ的转变率接近１００％。应用ＦＴ－ＩＲ对于ＴＡＩＣ的辐射转化反应进行了表征。     

RSI独具特色的DMTAIV

ＲＳＩ独具特色的ＤＭＴＡＩＶ温特美国流变仪科学有限公司美国流变仪科学有限公司（ＲｈｅｏｍｅｔｒｉｃＳｃｉｅｎｔｉｆｉｃＩｎｃ．）带有高级操作和分析软件的热分析仪如：ＤＳＣ，ＴＧＡ，ＤＭＴＡ，ＴＭＡ，ＳＴＡ，ＤＥＴＡ等，流变仪如ＡＲＥＳ，ＳＲ２００／５...     

铝合金中高含量铜的快速测定

研究了Ｃｕ－ＥＤＴＡ络合物的吸收曲线，提出了ＥＤＴＡ光度法测定铝合金中高含量铜的方法。该方法新颖，简单，快速，准确度高，重现性好。     

选择性螯合滴定法测定电镀液和镀层中铜的含量

本法先用ＥＤＴＡ螯合Ｃｕ＾２＋和其他金属阳离子，然后加入ＤＬ－半胱氨酸作为释放剂分解Ｃｕ－ＥＤＴＡ释放出的ＥＤＴＡ用Ｐｂ＾２＋标准溶液返滴定，以ＸＯ－ＭＴＢ－ＣＰＢ为混合指示剂，滴定终点颜色变化敏锐，测定结果准确，并对多种金属离子的干扰进行了研究。     

CuO and CuO-ZnO catalysts supported on CeO2 and CeO2-LaO3 for low temperature water-gas shift reaction

This paper describes an investigation on CuO and CuO-ZnO catalysts supported on CeO₂ and CeO₂-La₂O₃ oxides, which were designed for the low temperature water-gas shift reaction (WGSR). Bulk catalysts were prepared by co-precipitation of metal nitrates and characterized by energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), surface area (by the BET method), X-ray photoelectron spectroscopy (XPS), and in situ X-ray absorption near edge structure (XANES). The catalysts' activities were tested in the forward WGSR, and the CuO/CeO₂ catalyst presented the best catalytic performance. The reasons for this are twofold: (1) the presence of Zn inhibits the interaction between Cu and Ce ions, and (2) lanthanum oxide forms a solid solution with cerium oxide, which will cause a decrease in the surface area of the catalysts. Also the CuO/CeO₂ catalyst presented the highest Cu content on the surface, which could influence its catalytic behavior. Additionally, the Cu⁰ and Cu¹⁺ species could influence the catalytic activity via a reduction-oxidation mechanism, corroborating to the best catalytic performance of the Cu/Ce catalyst.     

(锌、铜、锰)复合脱硫剂的制备及性能研究

用共沉淀法制备纳米脱硫剂前躯物,以硅铝酸盐为载体造粒成型,经450℃煅烧6h得到三元金属氧化物脱硫剂,此脱硫剂在240℃无氧条件下精脱H2S,且颗粒平均直径为1.0mm时,其穿透硫容可达33.5%,是一种适合于中低温条件下脱硫的脱硫剂。     

中国专用氧化镁开发现状及其发展建议

介绍了氧化镁系列产品应用领域及生产现状,中国专用氧化镁如活性氧化镁、电工级氧化镁、硅钢级氧化镁、高纯氧化镁等开发是成功的,其中高纯氧化镁已达到世界领先水平;硅钢级氧化镁不仅已工业化,并成功应用于武钢硅钢片的生产上,取得显著经济效益,但总体上看研发技术虽然成功,工业化生产量还不足。提出了中国专用氧化镁发展必须充分利用中国十分丰富镁资源,扬长避短,发挥原料及生产方法优势,采用先进设备,提升装置及自控水平,建立万吨级骨干企业,提高专用化率等建议,提高精细氧化镁品种及产量以满足国内外市场需求。     

金属氧化物吸收微波辐射的能力与其结构的关系

考察了８种金属氧化物及６种复合金属氧化物在微波场中的升温行为，并对升温行为与其结构的关系进行了初步探讨。     

Sintering of Zinc Oxide Doped with Antimony Oxide and Bismuth Oxide

The phase change, densification, and microstructure development of ZnO doped with both Bi₂O₃ and Sb₂O₃ are studied to better understand the sintering behavior of ZnO varistors. The densification behavior is related to the formation of pyrochlore and liquid phases; the densification is retarded by the former and promoted by the latter. The pyrochlore phase, whose composition is Bi_3/2ZnSb_3/2O₇, appears below 700°C. The formation temperature of the liquid phase depends on the Sb/Bi ratio: about 750°C for Sb/Bi < 1 by the eutectic melting in the system ZnO—Bi₂O₃, and about 1000°C for Sb/Bi > 1 by the reaction of the pyrochlore phase with ZnO. Hence, the densification rate is determined virtually by the Sb/Bi ratio and not by the total amount of additives. The microstructure depends on the sintering temperature. Sintering at 1000°C forms intragrain pyrochlore particles in ZnO grains as well as intergranular layers, but the intragrain particles disappear at 1200°C by the increased amount of liquid phase, which enhances the mobility of the solid second phase.     

非水解溶胶-凝胶过程制备锡/硅复合氧化物

以无水四氯化锡和正硅酸乙酯为前驱物、环己烷为溶剂,在无氧无水条件下采用非水解溶胶-凝胶过程制备了锡/硅复合氧化物,并对其进行了表征分析。结果表明,在原料Sn/Si摩尔比为1∶2、反应温度为30℃、焙烧温度为500℃时,所得复合氧化物的产率为31.3%,Sn/Si摩尔比为7.4∶1,粒径10nm左右,比表面积22.58cm2.g-1,平均孔径14.3nm,比孔容0.047cm3.g-1,主要为颗粒堆积孔;复合氧化物的主要组成为无定形氧化硅和氧化锡晶体,在焙烧温度达到500～600℃时仍有Sn-O-Si杂键存在。     

氧化钛对氧化铬材料烧结特性的影响

以Cr_2O_3微粉和TiO_2微粉为主要原料,聚乙烯醇为结合剂,经制浆、喷雾造粒、机压和等静压二次成型,在气氛炉内(氧分压分别控制在10Pa和0.1Pa),1 500℃保温3h烧成制备氧化铬样品.研究了氧化钛加入量(质量分数为1%～5%)对Cr_2O_3材料烧结特性的影响.结果表明:TiO_2能显著促进Cr_2O_3材料的烧结,随着TiO_2加入量的增加,样品的体积密度迅速增加,显气孔率迅速下降;加入3%TiO_2基本能全部固溶到Cr_2O_3晶粒内,形成固溶体;当TiO_2的加入量超过3%时,富余部分形成钛铬化合物Cr_2Ti_(n-2)O_(2n-1)(3相似文献   

Effect of Additives on the Hydration Resistance of Materials Synthesized from the Magnesia–Calcia System

The effect of a variety of doping additives on the hydration resistance of calcined materials in the MgO–CaO system was investigated. Samples were prepared from lightly calcined flotation magnesite that was mixed with dolomite, as well as from analytically pure CaO and MgO; then, the samples were doped with additives that contained cations with various valences (monvalent to tetravalent). Both the hydration rate and the powdering rate were measured. The important role of the higher-valence cations in improving the hydration resistance of the MgO–CaO materials was revealed. This behavior is believed to be due to the formation of vacancies in solid solutions of CaO or MgO with higher-valence cations. The Ti⁴⁺ cation forms a solid solution with CaO, which reduces the Ca²⁺ concentration and leads to the improved hydration resistance of calcined materials from the MgO–CaO system.     

Differences in Wetting Characteristics of Bi2O3 Polymorphs in ZnO Varistor Materials

Detailed analysis of the microstructure of grain boundaries, especially triple-grain and multiple-grain junctions, in ZnO varistor materials has been performed using transmission electron microscopy. Different polymorphs of Bi₂O₃ are shown to exhibit different wetting properties on ZnO interfaces. Recent investigations suggest that the equilibrium configuration consists of crystalline Bi₂O₃ in the triple-grain and multiple-grain junctions and an amorphous bismuth-rich film in the ZnO/ZnO grain boundaries. The present investigation supports this suggestion for δ-Bi₂O₃ and also adds to the microstructural image and wetting properties of α-Bi₂O₃.     

Porous niobium oxide films prepared by anodization in HF/H3PO4

Ordered porous niobium oxide with the diameter of less than 10 nm and the aspect ratio of more than 20 is prepared by anodization of niobium foils at 2.5 V in the mixture of 1 wt% HF and 1 M H₃PO₄ for 1 h. In this study, the effects of the mixed electrolytes, anodic potential and anodization time on the preparation of porous niobium oxide are described based on the current-time transients during anodization and morphological observations. It is founded that a single HF electrolyte leads to the formation of pores as well as the fast dissolution of formed pores at the surface. The dissolution of the formed oxide is significantly retarded by the addition of appropriate amount of H₃PO₄.