Friction and adsorption properties of normal and high-oleic soybean oils

The steel/steel boundary friction properties of soybean oil (SBO) and high-oleic soybean oil (HOSBO) are compared. HOSBO is significantly more saturated than SBO and more oxidatively stable. Changes in degree of unsaturation affect lateral interactions of adsorbate molecules, which in turn affects their adsorption and, hence, their boundary lubrication properties. To investigate this possibility, the free energies of adsorption (ΔG _ads) of SBO, HOSBO, and methyl laurate (ML) were determined from the analysis of friction-derived adsorption isotherms using the Langmuir and Temkin adsorption models. The results showed a stronger adsorption for the vegetable oils than for ML, an indication of multiple interactions between the ester groups of the triglycerides and the steel surface. The result also showed no difference in the ΔG _ads values of SBO and HOSBO obtained using either the Langmuir or Temkin models. This was interpreted as an indication of the lack of appreciable net lateral interaction between triglyceride adsorbates.     

Hydrotreating processes for catalytic abatement of water pollutants

Opportunities and problems in application of catalytic hydrotreating processes, which are presented a viable approach in the abatement of water pollutants, are discussed. Analysis of the hydrodechlorination (HDC) and hydrodenitrification (HDN) using Pd-based catalysts supported on various materials like granulated activated carbon (GAC), fibrous activated carbon cloths (ACCs) or glass fiber cloths (GFCs) studied recently in our laboratory suggests the following perspectives:

Exhaustive regeneration of Pd/GAC saturated with p-chlorophenol can be achieved in a two-step approach, incorporating gas-phase HDC by hydrogen followed by oxidation by air.

Pd/ACC catalysts are good candidates for the liquid-phase HDC showing activity higher than that of Pd/GAC or Pd/GFC; the high adsorption capacity of Pd/ACC lead suggesting its use in a technology with periodic adsorption and HDC, in similarity to adsorption with regeneration of GAC.

Pd/GFC and Pd–Cu/GFC are promising catalyst for removal of nitrites and nitrates, showing activity and selectivity that compares favorably with those of powdered catalysts.

中空聚合物微球的制备Ⅲ.种子扩径的影响

以预乳化液连续滴加进料的三段乳液聚合结合碱酸溶胀处理制备了单分散性良好、大粒径的聚(甲基丙烯酸-甲基丙烯酸甲酯-丙烯酸丁酯)/聚(甲基丙烯酸-苯乙烯)中空聚合物微球。实验发现,在二段乳液聚合种子扩径中,种子乳胶粒数目、乳化剂用量、预乳化液滴加时间等对避免新乳胶粒的生成、扩大种子乳胶粒的粒径有影响,并找到了各自的较优值;扩径单体中的丙烯酸丁酯含量显著影响扩径乳胶粒聚合物的玻璃化温度,进而决定碱酸处理温度。     

钾长石含量对硬质粘土烧结的影响

以硬质粘土粉(w(Al2O3)>38%,粒度为0.002～0.11mm)和钾长石粉(w(K2O Na2O)=13.13%,粒度为0.005～0.11mm)为原料,配制成钾长石粉加入量分别为0、3.76%、5.30%和6.84%的试料(对应的w(K2O Na2O)分别为0.11%、0.6%、0.8%和1.0%),湿磨2h,烘干后以150MPa压力压制成20mm×10mm的试样,然后在1500～1600℃煅烧3h。对煅烧后试样进行了物理性能检测、物相分析和显微结构分析,以研究钾长石含量对粘土烧结的影响。结果表明:钾长石粉加入前后试样的烧结温度分别为1550℃和1500℃;加入钾长石能消除粘土原料煅烧过程中形成的方石英相,使烧成试样中只出现莫来石晶相;加入3.76%～6.84%钾长石粉的试样中莫来石含量达61%～66%,并且莫来石发育较好,呈针状,长度达8μm,直径约0.5μm。     

Confinement, composition, and spin-coating effects on the glass transition and stress relaxation of thin films of polystyrene and styrene-containing random copolymers: Sensing by intrinsic fluorescence

The glass transition temperatures (T_gs) of polystyrene (PS) and styrene/methyl methacrylate (S/MMA) random copolymer films are characterized by intrinsic fluorescence, i.e., monomer fluorescence from an excited-state phenyl ring and excimer fluorescence from an excited-state dimer of two phenyl rings. The T_g is determined from the intersection of the rubbery- and glassy-state temperature dependences of the integrated fluorescence intensity measured upon cooling from an equilibrated state. With PS, the effects of nanoconfinement on T_g and the transition strength agree with results from studies using probe fluorescence and ellipsometry. The T_g-nanoconfinement effect is “tuned” by copolymer composition. As S-content is reduced from 100 mol% to 22 mol%, the confinement effect changes from a reduction to an enhancement of T_g relative to bulk T_g. Intrinsic fluorescence is also a powerful tool for characterizing relaxation of residual stresses. Stresses induced by spin coating affect local conformations, which in turn affect excimer and monomer fluorescence and thereby integrated intensity. The heating protocol needed to achieve apparently equilibrated local conformations is determined by equivalence in the integrated intensities obtained upon heating and subsequent cooling. While partial stress relaxation occurs upon heating in the glassy state, full relaxation of local conformations requires that a film be heated above T_g for times that are long relative to the average cooperative segmental relaxation time. For example, in thin and ultrathin films, equilibration is achieved by heating slowly (∼1 K/min) to 15-20 K above T_g. Dilute solution fluorescence of PS and S/MMA copolymers is also characterized and compared to reports in the literature.     

A comparison of concentration-glasses and temperature-hyperquenched glasses: CO2-formed glass versus temperature-formed glass

Prior work from this laboratory has reported anomalous differences in the viscoelastic responses between temperature-jump formed glasses and carbon dioxide pressure-jump or relative humidity formed glasses. In the present work, we investigate the anomalous behaviour further by examining the structural response of an epoxy resin after pre-annealing treatments. In particular, we have measured the volume change of amine-cured diglycidyl ether of bisphenol A after thermal and carbon dioxide pressure (PCO₂) treatments. Our results show that contrary to prior interpretations in the literature, a plasticizer quench is different from a temperature hyperquench. Consistent with our prior work, the CO₂-formed glass is more stable than the temperature-formed glass in spite of the former having a higher excess volume. Our new results show that the stability persists to above the nominal glass temperature, contrary to what happens in a temperature hyperquench.     

玻纤增强聚脂弯管应变导纳试验研究及其动应力分析

探讨了测定玻纤增强聚脂弯管应变导纳的试验方法。给出了力通道和应变通道的标定曲线。确定了玻纤聚脂弯管的第一、第二阶模态频率和阻尼比以及单位力幅下的动应变值。借助应变导纳的幅频特性和相频特性分析了弯管动应力。还用静态试验验证了动态测试的正确性     

有限元方法在玻璃成形工艺研究的应用

分析了玻璃在熔融状态下的力学性质、弹粘塑性和刚粘塑性本构方程以及玻璃成形的力学特性等,并结合玻璃成形的热力学公式,介绍了对玻璃成形的热力耦合分析的基本原理,还介绍了在玻璃成形过程中玻璃和模具之间的非线性接触、摩擦问题的求解,自动网格重划分技术.为了说明玻璃成形有限元分析的过程,最后介绍了利用三维大变形有限元方法来模拟电视显像管管屏的压制成形过程和饮料瓶吹制成形过程.     

Na_2O－ZnO－CaO－Al_2O_3－SiO_2烧结微晶玻璃的试制

Ｎａ＿２Ｏ－ＺｎＯ－ＣａＯ－Ａｌ＿２Ｏ＿３－ＳｉＯ＿２烧结微晶玻璃的试制刘世权，许淑惠，袁怡松，杨晓晶（西北轻工业学院７１２０８１）ＳｉｎｔｅｒｅｄＮａ＿２Ｏ－ＺｎＯ－ＣａＯ－Ａｌ＿２Ｏ＿３－ＳｉＯ＿２ＧｌａｓｓＣｅｒａｍｉｃｓ￥ＬｉｕＳｈｉｑｕａｎ...     

微晶玻璃的着色工艺及其研制

通过以CaO—Al2O3-SiO2系统玻璃为基础组成，研究了着色剂含量及不同种类氧化物对该系统微晶玻璃装饰板颜色的影响，并对其着色机理及研制工艺进行了探讨和总结，得出一些经验和体会，还针对生产中容易出现的问题提出了相应的改进建议与措施。