Facile fabrication and property of biocompatible and biodegradable cellulose-coated PMMA composite microspheres by Pickering emulsion system

SCNWs-coated poly[methyl methacrylate] (PMMA) composite microspheres (PMMA@SCNW CMs) were fabricated by the Pickering emulsion stabilized by cellulose nanowhiskers (SCNW) combined with the solvent evaporation method. The structure and morphology of the CMs affected by the concentration of PMMA in dichloromethane solution and the volume ratio of water-to-oil were investigated and further characterized by polarized optical microscopy, confocal laser scanning microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. Finally, methyl red as model drug was loaded into CMs and exhibited fine drug–controlled release performance. This method will also be available to other polymers for preparing composite microspheres.     

电场强化微槽道结构蒸发器传热特性的实验研究

为了研究矩形微槽道表面施加电场后对蒸发/沸腾换热特性的影响,以R141b为工质展开实验.实验结果表明:高压电场对微槽道结构的蒸发/沸腾换热有明显的强化作用,蒸发/沸腾换热系数随着电场强度的增加而增大,换热强化系数相比未施加电场的状况最大增加了0.7,在高热流密度时,换热强化系数的变化则趋于平缓.     

花卉/空气表面分子膜保鲜性能研究

研究了棕榈酸烷醇酰胺、棕榈酰胺和AEO－1分子膜在切花／空气界面上的成膜状态及其抑制切花生命过程。研究表明：在实验条件下，它们能够在切花表面形成分子膜，显著降低切花表面的水分蒸发、呼吸作用及减少细胞组织损伤；在不考虑其他保鲜措施的前提下，能够使切花寿命延长50％左右。     

垂直管内降膜载气蒸发的研究

在蒸发的降液膜表面引入惰性载气,可以有效地强化降膜蒸发传热。研究了液体流量、载气流量、壁面热负荷及料液物性等对降膜载气蒸发传热的影响。建立了数学模型,并进行了数值求解。实验结果表明,采用降膜载气蒸发,可提高传热膜系数,降低壁面过热度。还将模型计算结果与实验结果进行了比较。     

Characterization of Mixed Cobalt-Molybdenum Oxides Prepared by Evaporative Decomposition of Solutions

The synthesis of Co-Mo oxides by the evaporative decomposition of solutions method has been investigated. The oxides were prepared from atomized metal salt solution precursors decomposed in less than 3 s in air at 700°C. The materials obtained were primarily hollow spheres (1 to 6 μm) composed of fine (100 to 500 Å (10 to 50 nm)) crystallites. CoO, Co₂Mo₃O₈, and CoMoO₄ were the major crystalline phases identified. The Co-Mo oxides were depleted in Mo relative to the precursor solutions and could not be prepared with Co/Mo atom ratios less than unity. A schematic Co-Mo-O isothermal section was constructed to explain the compositions, morphologies, and phase distributions observed for materials having different Co/Mo ratios. The loss in Mo was explained by the high vapor pressure of MoO₃.     

连体热机-热泵用于烧碱蒸发工艺的探讨

根据连体热机-热泵的增压比和引射系数较高的特点,将其用于烧碱溶液的并联分体式热泵蒸发工艺中,适当改变工艺参数后,采用尽可能小的蒸汽增压比以提高热泵的引射系数,可取得节能28%以上的显著效果,对于利用现有装置进行扩能改造更为有利。     

Synthesis of Pt Nanowires Inside Aerosol Derived Spherical Mesoporous Silica Particles

Spherical mesoporous silica particles prepared by evaporation induced self assembly (EISA) were used as templates to form Pt nanowires. Transmission electron microscope (TEM) images of these aerosol-derived silica particles reveal hexagonally ordered pores coiled within each particle, with no obvious termination of the pores on the external surface. Near the particle surface the pores are seen to run parallel to the surface, consistent with the external constraint of spherical geometry. For MCM-41 type mesoporous materials, the pores are straight and accessible at either end for pore filling, but for spherical silica particles prepared by EISA, the pores are not open to the external surface. Hence it is remarkable that Pt nanowires can be formed within the closed pores inside these spherical silica particles, where conventional mechanisms of pore filling would not be expected to be operative. These results suggest that the silica walls in these mesoporous silica allow transport of volatile Pt complexes during wet reduction in H₂. The permeability to gases makes these spherical silica particles especially suitable for gas phase catalytic reactions, while at the same time confining metallic particles within the silica pores.     

多效蒸发系统优化设计研究

提出了多效蒸发系统优化设计模型。从全蒸发系统出发，本着年费用最小为目标，推导了多效蒸发的热经济学模型，并以此对实例进行了非线型规划。计算结果表明，优化设计比常规设计可节省年费用在１０％以上。     

聚氯乙烯/聚丙烯腈共混超滤膜的研究 Ⅲ.制膜工艺条件对共混超滤膜结构与性能的影响

考察制膜工艺条件对于PVC/PAN 共混超滤膜结构与性能的影响,发现该影响与共混高聚物本身的相容性关系密切。虽然凝胶浴温提高都使膜的透水率提高而截留率下降,但相容性好可在截留率下降较小的情况下较大地提高透水率;利用少量NaCl 对凝胶浴的添加,也只有在相容性好时才能在不降低透水率的情况下有效改善截留率;蒸发时间的影响也因相容性不同而异,但延长蒸发时间并不可取。     

废发动机润滑油循环使用的工艺技术

本文介绍了废发动机润滑油的循环使用工艺，并对废发动机润滑油的资源化利用工艺的特点作了比较。