响应曲面法优化改性漂珠对水中三氯乙烯的吸附性能

本文对工业废弃物漂珠进行煅烧改性,制备易回收的吸附材料。以三氯乙烯作为目标污染物,研究改性漂珠吸附污染物的可行性和不同改性参数对去除污染物的影响。通过Box-Behnken设计-响应曲面法以煅烧温度、煅烧时间及粒径为影响因素,建立以三氯乙烯吸附量为响应值的预测模型,对改性漂珠进行XRD、SEM-EDS、BET等表征分析以探讨材料的吸附性能。结果表明,煅烧改性后的漂珠表面疏松多孔,比表面积增大2.4倍左右,影响改性漂珠吸附水中三氯乙烯的因素顺序依次为:煅烧时间＞煅烧温度＞粒径。模型优化的最优吸附条件为:粒径为0.25~0.38 mm,煅烧温度为640 ℃,煅烧时间为80 min,预测吸附最大值为1 326 μg/g,试验值为1 344 μg/g,两者仅相差1.4%。通过高温煅烧改性的漂珠具备更优良的吸附性能,是一种可大规模生产、以废治废、易回收的环保材料。     

Biodegradable polymersomes from four‐arm PEG‐b‐PDLLA for encapsulating hemoglobin

A series of four‐arm star block copolymers poly(ethylene glycol)‐block‐poly(d,l ‐lactide) (PEG‐PDLLA) with different hydrophobic length were synthesized by ring‐opening polymerization of lactide and characterized using ¹H NMR and gel permeation chromatography (GPC). These copolymers could self‐assemble in aqueous solution to form the vesicle structure with controlled size and morphologies. Transmission electron microscopy (TEM) and DLS show the polymersomes are spherical with diameter of 70～500 nm. The polymersomes made by direct hydration of copolymer thin films in water exhibit the controllable ability of encapsulating hemoglobin under mild condition. The hemoglobin content in the polymersomes could reach to 35 wt %. More importantly, the encapsulated hemoglobin keeps its own bioactivity and is capable of binding oxygen. This hemoglobin‐encapsulated four‐arm PEG‐PLA polymersomes could have the potential to be applied as an artificial oxygen carrier for transfusion. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40433.     

Mo polyoxometalate nanoparticles inhibit tumor growth and vascular endothelial growth factor induced angiogenesis

Tumor growth depends on angiogenesis, which can furnish the oxygen and nutrients that proliferate tumor cells. Thus, blocking angiogenesis can be an effective strategy to inhibit tumor growth. In this work, three typical nanoparticles based on polyoxometalates (POMs) have been prepared; we investigated their capability as antitumor and anti-angiogenesis agents. We found that Mo POM nanoparticles, especially complex 3, inhibited the growth of human hepatocellular liver carcinoma cells (HepG2) through cellular reactive oxygen species levels’ elevation and mitochondrial membrane potential damage. Complex 3 also suppressed the proliferation, migration, and tube formation of endothelial cells in vitro and chicken chorioallantoic membrane development ex vivo. Furthermore, western blot analysis of cell signaling molecules indicated that Mo POMs blocked the vascular endothelial growth factor receptor 2-mediated ERK1/2 and AKT signaling pathways in endothelial cells. Using transmission electron microscopy, we demonstrated their cellular uptake and localization within the cytoplasm of HepG2 cells. These results indicate that, owing to the extraordinary physical and chemical properties, Mo POM nanoparticles can significantly inhibit tumor growth and angiogenesis, which makes them potential drug candidates in anticancer and anti-angiogenesis therapies.     

Rheological properties and related screen-printing performance of low-temperature silver pastes for a-Si:H/c-Si heterojunction solar cells

Four different low-temperature silver pastes were utilized to make metal grids by screen printing for silicon heterojunction solar cells. The rheological behaviors of the low-temperature silver pastes were characterized by viscosity test, thixotropy test, oscillatory stress sweep test and creep-recovery test. The correlationship between the screen-printing performance and the rheological properties was investigated. It was found that the shear thinning behavior and the thixotropy behavior of the silver pastes were desirable for the screen-printing process. An obvious viscoelastic behavior of the silver paste was also helpful for improving its printability. Further, good recovery and low creep and recovery compliances could minimize the printing defects and the tendencies to bleed out during the screen-printing, and thus increase the aspect ratio of the printed grids.     

Kinetics and equilibrium of Cu(II) adsorption onto chemically modified orange peel cellulose biosorbents

A series of orange peel cellulose biosorbents has been specifically prepared by different chemical modifications to understand the mechanism of copper adsorption from chloride solutions. The different biosorbents and raw orange peels were characterized using elemental analysis and Fourier transform infrared spectroscopy (FTIR). The acidic and basic sites and pH of zero charge were also determined. The influences of pH, contact time, initial copper concentration and solid/liquid ratio on copper removal were examined. The maximum adsorption capacity of copper was 1.22 mol/kg, using orange peel esterified by 0.6 mol/L citric acid at 80 °C after 0.1 mol/L NaOH saponification. A comparison of different isotherm models revealed that the combination of Langmuir and Freundlich (L–F) isotherm model fitted the experimental data best. Results indicate that the chemically modified orange peel cellulose can provide an efficient and cost-effective technology for eliminating copper from aqueous solution.     

高密度电法在岩溶洞隙探测中的应用

岩溶的发育对工程建设的影响有较大的影响。主要介绍了高密度电法的原理,并应用该法探测灰岩地区岩溶发育和分布情况,取得了较好的效果。     

多系统信息整合办公系统解决方案

在设计新的办公系统的时候,大多数企业都会遇到与部分已长时间运行的定制应用系统整合的问题,如何整合多个系统的基础上设计新的办公系统,实现各系统间信息互通和共享,是本文分析的主要内容。     

丁基橡胶压敏胶粘带的制备及其性能研究

以丁基橡胶为主要原料研制出了丁基橡胶压敏胶粘带,讨论了丁基橡胶、增黏剂、增塑剂和填料用量等对胶粘带性能的影响,研究了其对三元乙丙橡胶防水卷材接缝的粘结作用。     

铝合金时效成形及时效成形铝合金

介绍了铝合金时效成形的方法、基本原理、工艺特点及应用情况,概括了国外研究铝合金时效成形工艺及相关可时效成形铝合金的现状,重点阐述了时效成形对铝合金微观组织结构的影响.