Bile acids as constituents for dental composites: in vitro cytotoxicity of (meth)acrylate and other ester derivatives of bile acids.

Methacrylic derivatives of bile acids have been synthesized for use as monomers in dental composites. Polymeric dental materials are known to leach cytotoxic unreacted monomers and degradation products. In this study, the in vitro cytotoxicity of bile acids and their derivatives towards 3T3 fibroblasts has been evaluated by colorimetric MTT assay and compared with that of the common dental monomers BisGMA, UDMA and TEGDMA. In general, the bile acids and their derivatives induced mitochondrial dysfunction at similar or higher concentrations than the commercial dental monomers. Certain monomers did not influence MTT response over their entire range of solubility.     

一个通用代理计费系统开发框架的设计与实现

用户在不同的网络环境中选择不同的代理软件实现上网和用户管理，这些代理软件既有共性又各具特色，为减少开发不同代理计费软件的工作量，提高开发效率，加快开发周期，提出利用软件重用的思想，将代理软件的差异集中到少数几个类的实现上，设计并实现一个通用代理计费系统开发框架，基于此框架利用相对简单的步骤开发了基于SQUID的代理计费系统，验证了框架的实用性和可行性，达到了设计目标。     

焦化全馏分油加氢精制装置的技术改造

介绍了中国石化扬子石油化工股份有限公司炼油厂焦化全馏分油加氢精制装置高压分离系统、分馏塔系统等改造情况。实际运转表明 ,改造后装置处理能力由 0 .5Mt/a提高到 0 .6Mt/a ,液体收率由 96.5 0 %提高到96.99% ,能耗降至 15 38.1MJ/t ,每年可多创经济效益 70 0× 10 4RMB $。     

山西资源环境状况探析

在对山西资源现状分析的基础上，就山西如何走新型工业化道路，如何正确地处理山西日益突出的生态环境，自然资源和社会经济发展的矛盾问题，提出了对策和建议。     

Precipitation of barium sulfate nanoparticles via impinging streams

The impinging streams technology (abbreviated as IS) has good micromixing in the precipitation processes. The experiments were loaded with two reactants, BaCl₂ and Na₂SO₄, to prepare BaSO₄ in the impinging streams reactor, comparing with those in the direct precipitation (DP) reactor. XRD and TEM were used to analyze the crystal type, the morphology and size of particles through the photographs. The results indicate the size of the particles from IS is about 30 nm and of narrower distribution and finer dispersibility than that from DP.     

The effect of the scale of horizontal subsurface flow constructed wetlands on flow and transport parameters.

Horizontal subsurface flow constructed wetlands have proven their efficiency in treating wastewater and removing the pollutants of concern. Treatment efficiency depends on the wastewater residence time, which is a function of the hydraulic loading and the physical conditions of the constructed filter system, which can be described with effective parameters such as: hydraulic conductivity, porosity, dispersivity etc. Because spatial variability is often scale dependent, these effective parameters may be affected by the scale of the system being studied. In this paper the results of tracer experiments in constructed filters using saturated horizontal flow at three scales (small and medium lab scales and full-scale system) using the same filter media is reported. Light-weight aggregate (filter media termed Filtralite-P) was used at all scales. Increasing the scale was associated with increasing dispersivity, meanwhile hydraulic conductivity experienced dramatic reduction and variation by increasing the examined scale. Observed changes in the hydraulic parameters indicate that heterogeneity at different scales should be taken into account when the performance of LWA filters are evaluated from small-scale experiments.     

Techniques and Apparatus for Measuring Rotational Core Losses of Soft Magnetic Materials

In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.     

Solution-chemistry analysis of ammonium bicarbonate consumption in rare-earth-element precipitation

A solution-chemistry analysis is applied to estimating the consumption of ammonium bicarbonate in the recovery of rare-earth (RE) elements from leachates of weathered clays. The theoretical analysis shows that a two-step process is needed for recovering RE from the leachates of the weathered clays by precipitation using ammonium bicarbonate. The first step is a precipitation at solution pH 5 to remove impurities such as Fe and Al. The second step is to precipitate RE by adjusting the solution pH above 8. The consumption of ammonium bicarbonate was found to depend on the concentration of RE elements and impurities in the leachates. The total amount of ammonium bicarbonate consumption for the entire process was determined experimentally, and the results showed an excellent agreement with that calculated based on solution-chemistry analysis. The decomposition of H₂CO₃ was identified as one of the main causes of ammonium bicarbonate overdose, accounting for up to 41 pct in comparison to 20 pct consumption for the removal of impurities. The amount of ammonium bicarbonate required in terms of the NH₄HCO₃: RE₂O₃ (RE oxides) molar ratio was found to be 4:1 for maximal RE recovery. An overall RE recovery around 90 pct was achieved with a product purity being about 90 pct.