高效石墨浮选剂的合成

高效石墨浮选剂的合成金婵，薛玉，汪进，刘欣荣，秦英海（哈尔滨工业大学应用化学系哈尔滨１５０００１）（大庆石化总公司大庆）关键词石墨，浮选剂，合成，混合烃由于石墨具有良好的力学性能、导电、高熔点等性质，广泛用于原子能、宇航和民用工业。隐晶质石墨属于微晶...     

手性液晶掺杂剂（S）—4‘—辛氧基—4—（2—酰氧基—丙氧基）联苯的合成

手性液晶掺杂剂（Ｓ）┐４┐辛氧基┐４┐（２┐酰氧基┐丙氧基）联苯的合成马汝建李培荣国斌＊（华东理工大学化学系上海２００２３７）关键词铁电液晶材料，手性液晶掺杂剂，合成，手征性１９９７－０２－０３收稿，１９９７－０８－０７修回铁电液晶显示器所用的材料...     

The effect of grass fiber filler on curing characteristics and mechanical properties of natural rubber

Natural rubber is reinforced with a novel type of grass fiber (Cyperus Tegetum Rox b). The effects of fiber loading of different mesh sizes on curing characteristics and mechanical properties of grass fiber filled natural rubber composite are studied. Since 400 mesh grass fiber loaded natural rubber composite shows superior mechanical properties, therefore the effect of silane coupling agent was studied for this particular composite. Here composites were prepared by using water leached grass fiber. Optimum cure time increases with the increase in fiber loading but the change in scorch time is less. The same trend of increase in optimum cure time is observed in the presence of Si69. But the value is higher compared to that of rubber composite without Si69. With increase in the fiber loading, modulus and hardness of the composite increases but tensile strength decreases. The mechanical properties of the composite, namely moduli at 200 and 300% elongation and hardness increase in the presence of Si69 but tensile strength is less compared to that of the composite without Si69. Elongation at break is not much affected due to the presence of Si69. Copyright © 2004 John Wiley & Sons, Ltd.     

Preparation of a novel molecularly imprinted polymer using a water-soluble crosslinking agent

A molecularly imprinted polymer was prepared using a water-soluble crosslinking agent. An ionic complex was utilized as the assembly for the template molecule and the functional monomer, and water as porogenic solvent during preparation of the imprinted polymer. The results of chromatographic evaluations for the prepared polymer suggested that the polymer had much lower hydrophobicity compared with usual octadecyl group bonded silica or the usual molecular imprinted polymer prepared from ethyleneglycol dimethacrylate, and the selective recognition ability for template molecule in the completely aqueous condition.     

Selective Formation of Spinel Iron Oxide in Thin Films by Complexing Agent-Assisted Sol-Gel Processing

The structure of iron oxide was controlled by regulating the hydrolytic polymerization of aquo iron complexes with organic polydentate ligands such as diols. Iron oxides were prepared by calcining the precursor polymers obtained from iron nitrate nonahydrate and diols. When the diols were 1,2-pentanediol, 1,2-hexanediol and 1,2-octanediol, α-Fe₂O₃ with corundum structure appeared exclusively or as the main crystalline phase, in spite of the amount of diol used and the calcination temperature. In the case of 1,2-decanediol and 1,2-dodecanediol, when five moles of the diols were used to one mole of iron nitrate and the calcination temperatures were below 400°C, ψ-Fe₂O₃ with spinel structure appeared as the main phase and, when less than five moles of the diols were used, α-Fe₂O₃ appeared exclusively or as the main phase, irrespective of the calcination temperature. This tendency was also observed in thin films. Thus, a transparent magnetic film composed of γ-Fe₂O₃ could be prepared by applying a benzene solution of the iron polymer, obtained with 5 equivalents of 1,2-decanediol, on quartz and calcining the gel film at 350°C.     

一测多评方法应用于高效液相色谱法测定防晒产品中15种防晒剂的含量

选用CAPCELL PAK C18色谱柱为分离柱,柱温为30℃,进样体积为10.0μL,并用不同比例的(A)甲醇、(B)四氢呋喃和(C)0.008 2mol·L^-1高氯酸溶液的混合液作为流动相,按程序梯度洗脱模式对市售防晒产品中所用的15种防晒剂的标准品进行色谱分离,并在波长311nm处进行紫外检测。实样分析时,称取样品0.25g,用甲醇、四氢呋喃、水和高氯酸(体积比为250∶450∶300∶0.2)的混合液(以下简称混合溶剂)15 mL超声提取30 min,用混合溶剂定容至25.0mL,离心10min,分取上清液1.0mL,加入混合溶剂定容至10.0mL,经0.45μm滤膜过滤,取滤液按仪器工作条件进行高效液相色谱分析。结果表明:所测定的15种防晒剂在一定的质量浓度范围内与其对应的峰面积呈线性关系。选定其中的二苯酮-3为参照物,并根据其余14种化合物的质量浓度和峰面积计算了各化合物的相对校正因子和相对保留时间等参数,确定了用一测多评法(QAMS)测定防晒产品中15种防晒剂的条件。还对色谱柱的型号、色谱仪器的型号以及柱温、进样量等对相对校正因子和保留时间可能产生影响的因素进行了系统试验。证明了在选定的色谱柱型号的前提下,用QAMS方法可实现防晒产品中15种防晒剂含量的同时测定。应用QAMS方法测定了6个批次防晒产品中的防晒剂含量,所得结果与用标准曲线法计算的结果基本一致,表明QAMS方法在降低检测成本和节省检测时间方面效果显著。     

老年人彩度对比敏感度函数研究及滤波应用

为研究老年人彩色视觉频率响应特性，获取彩度对比敏感度与空间频率之间的函数关系，本文在LCH均匀颜色空间基础上，固定明度和色调角值，以彩度作为变量，设计人眼彩度对比敏感度实验，进行人眼视觉观察实验。获得彩度对比敏感度与空间频率的关系，并构建指数型对比敏感度函数模型。经分析表明老年人眼彩度对比敏感度随着空间频率的增加，产生先升高再缓慢降低的变化，各色调角下彩度对比度存在差异。经分析人眼对比敏感度差异与人眼视觉辨色特性有很大的相关性。并且，将构建的对比敏感度函数模型用于实现基于人眼视觉系统的滤波处理。     

Barium dichromate [BaCr2O7], a mild reagent for oxidation of alcohols to their corresponding carbonyls in non-aqueous polar aprotic media

Barium dichromate is used as a mild oxidizing agent for the selective conversion of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. Over-oxidation does not occur and primary alcohols undergo oxidation to the aldehyde. Primary and secondary benzylic alcohols are oxidized faster and more efficiently.     

发用防晒剂DDABDT的反相高效液相色谱法测定

建立了反相高效液相色谱法测定发用防晒剂二甲基对胺基苯甲酰胺丙基十二烷基二甲胺甲苯磺酸盐(简称DDABDT)的方法.采用的色谱条件为色谱柱Symmetry C8柱,流动相为V(乙腈):V(10 mmol/L NaAc)=65:35溶液(含体积分数0.02%三氟乙酸,pH5.04),流速1.0 mL/min;检测波长305 nm;进样量20μL.DDABDT质量浓度为0.05～1000 mg/L时,其浓度与峰面积呈良好的线性关系(R2＞0.999),检出限为0.02 mg/L(S/N=3).洗发水A中DDABDT的回收率在98.0%～102%之间,发样提取液中DDABDT的平均回收率在85%～108%之间.洗发水中DDABDT浓度测定日内和日间相对标准分别为1.2%,3.4%.头发吸附DDABDT含量测定日内和日间相对标准偏差(RSD)分别为9.1%,9.8%.同时以高效液相色谱-电喷雾离子化质谱对色谱法测定样品的DDABDT峰进行了验证.该方法已用于洗发水及头发吸附DDABDT的分析.     

气相色谱-质谱法分析土壤中神经性毒剂及糜烂性毒剂

建立了土壤中神经性毒剂及糜烂性毒剂GC—MS-SIM分析法，对土壤中6种毒剂的样品制备和二步萃取方法进行了研究；该法的回收率在80．7％～89．5％，6种毒剂在0．5～10mg/L范围内毒剂质量浓度和峰面积有良好的线性相关，方法检出限为4～20ng／g，该法适用于痕量化学战剂分析。