酯交换法制备生物柴油反应机理的研究进展

生物柴油作为一种环保型可再生能源,它的研究和应用引起了人们的广泛关注。酯交换法制备生物柴油的反应机理是该领域的研究热点。从量子化学方面介绍了酯交换法制备生物柴油反应机理的理论研究进展,讨论了不同催化活性中心对反应机理的影响,并对酯交换法制备生物柴油的理论研究进行了展望。     

GMCO/TiO_2复合改性有机硅苯丙树脂涂膜的制备及性能研究

利用马来酸酐和KH560对可再生资源蓖麻油进行改性,将—Si(OCH3)3引入到蓖麻油分子中得到了KH560和马来酸酐共改性蓖麻油(GMCO),利用核磁(1H-NMR)、全反射红外光谱(ATRFTIR)、凝胶渗透色谱(GPC)对GMCO的结构进行了表征。以KH560作为偶联剂通过溶胶-凝胶法将GMCO和钛溶胶与有机硅苯丙树脂进行复配得到GMCO/TiO2复合改性有机硅苯丙树脂涂膜,通过全反射红外光谱(ATR-FTIR)对产物结构进行了表征,并进行了热重分析(TG)及涂膜性能测试,结果表明:成功地对有机硅苯丙树脂进行了改性,改性后的涂膜其稳定性得到了提高,钛原子的引入能提高涂膜的附着力,且GMCO的引入及其用量的增加能分别改善涂膜的柔韧性和疏水性。     

Design of nitrogen-containing organic thermal stabilizer with resistance to “zinc burning” and its application

Using maleic anhydride and 6-amino-1,3-dimethyluracil as raw materials, by adding zinc oxide and introducing metal ions, the aminouracil zinc maleate (AM-Zn) was synthesized. The structure of the product was analyzed by Fourier transform infrared spectroscopy and ¹H NMR spectroscopy. The molecule contains ester group, carbon–carbon double bond, carboxylate and diazo group, which can be used as the main thermal stabilizer for poly(vinyl chloride) (PVC). The thermal stability and excellent resistance to zinc burning of AM-Zn were characterized by Congo red method, thermal aging method, thermal weight loss method, electrical conductivity, and other detection methods. In addition, the compound use of AM-Zn and CaSt₂ could further improve the thermal stability performance, which was excellent compared with the commercially available CaSt₂/ZnSt₂. The thermal stabilization effect was the best when CaSt₂/AM-Zn = 2:1, the initial whiteness could reach 50 min, and it was not completely blackened and aged within 80 min. The static stabilization time was 65 min, and the thermal stabilization time is increased by 40 min compared with CaSt₂/ZnSt₂. The thermal stabilization mechanism was analyzed, and the designed and synthesized AM-Zn, a multifunctional molecular structure, had a strong potential as a thermal stabilizer for PVC.     

高梯度磁选数学模型研究概况及发展方向

对高梯度磁选数学模型理论研究进行了综述，讨论了各数学模型存在的不足，指出了高梯度磁选数学模型的研究方向。     

Micromolding of PDMS scaffolds and microwells for tissue culture and cell patterning: A new method of microfabrication by the self-assembled micropatterns of diblock copolymer micelles

We introduce an innovative fabrication of the polymer scaffolds for tissue culture by utilizing the evaporation induced self-assembled micropatterns of polystyrene-block-poly(acrylic acid) (PS-b-PAA) diblock copolymer micelles. The microstructures were used as templates for micromolding a silicon elastomer, poly(dimethylsiloxane) (PDMS), into tissue scaffolds and microwells for cell patterning purpose. Cultivation of human epithelial cells (Calu-3 cell line) on the PDMS scaffolds demonstrates potential applications in tissue engineering and cell-based biosensors. The reported method is rapid, simple, economical, and versatile comparing with the existing microfabrication techniques.     

数字地形图管理系统的研制和开发

本系统基于新的国家标准和最新的ＡｕｔｏＣＡＤＭａｐ软件进行设计，能够对多种比例尺的地形图进行方便灵活的查询和拼接，自动记录和获取坐标值，引入栅格图象进行简单的编辑，根据用户需要检索符合要求的实际数据和信息，并设置相应的用户权限，提高数据信息的安全性。     

工业型CLLP-φ1000振动高梯度磁选机磁系设计

本文着重介绍了工业型CLLP-Φ1000振动高梯度磁选机矩形磁系的设计与计算．主要包括激磁线圈、铠装铁轭及冷却水量三个部分。同时对磁系的磁场性能进行了检测．结果表明．该设计是可靠的。     

用BP神经网络建立脉动高梯度磁选过程模型

用BP神经网络建立脉动高梯度磁选过程模型．对不同隐含层节点数的神经网络模型预测性能进行了评价，隐含层节点为13的神经网络模型选择为最佳模型．利用选择的最佳模型，对黄铜矿高梯度磁选进行模拟研究．模型研究结果表明，在相当宽操作的范围内，模型能够很好地预测磁选精矿中铜的品位和回收率．这说明建立的高梯度磁选模型合理可行．     

Effect of SSIE structure of Cu-exchanged β and Y on the selectivity for synthesis of diethyl carbonate by oxidative carbonylation of ethanol: A comparative investigation

Cu-exchanged β and Y catalysts were investigated by oxidative carbonylation of ethanol in the gas-phase reaction. Cuβ catalyst has shown better catalytic selectivity for oxidative carbonylation of ethanol to diethyl carbonate (DEC), without the principal by-product 1,1-diethoxyethane (DEE) for CuY catalysts. In order to investigate the effect of zeolite structure on the selectivity for products, computational analysis of molecular dimensions and diffusion parameters of DEC and DEE within Cuβ and CuY catalysts zeolite framework has been performed using molecular mechanics and quantum mechanics methods. The computational analysis results are in good agreement with the experimental results to some extent. DEC having a kinetic diameter of 3.663 Å and the lowest energy barrier was formed preferentially over both zeolites. However, the DEE molecule was not detected among the products over Cuβ because of its greater kinetic diameter 6.059 Å and higher energy barrier. The special architecture of β zeolite did not allow the diffusion of DEE molecules through its pores. The formation of the higher sterically hindered DEE over CuY catalyst could be explained by involvement of the outer surface.     

NaY ZEOLITE–SUPPORTED POTASSIUM SALT CATALYSTS FOR DIPROPYL CARBONATE SYNTHESIS FROM TRANSESTERIFICATION ROUTE

The catalytic synthesis of dipropyl carbonate (DPC) from transesterification of dimethyl carbonate and propyl alcohol over NaY zeolite–supported potassium salt catalysts was investigated at atmospheric pressure. K₂CO₃/NaY and KOH/NaY catalysts exhibited better catalytic activity than other potassium salt catalysts. From infrared resonance (IR), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), it could be concluded that K₂CO₃/NaY and KOH/NaY catalysts showed preferable order degree of zeolite structure, which was associated with higher dispersal of the active species K₂O and extraction for part of the non-framework silicon and aluminum of the system after alkali treatment. And the partial extraction of the non-framework silicon and aluminum allowed the reactants and the products to pass through the pore of the catalysts easily and facilitated catalytic performance for DPC synthesis.