浅析矿山工程造价失控原因与对策

针对当前矿山建设工程长期存在的工程造价不断提高、投资效果持续下降的问题,从矿山建设全过程的各个阶段,分析了矿山工程造价失控的主要原因,讨论了矿山工程造价控制的基本方法.     

邻甲酸甲酯苯磺酰胺合成工艺的优化

对邻甲酸甲酯苯磺酰氯进行纯化,以邻甲酸甲酯苯磺酰氯为原料合成邻甲酸甲酯苯磺酰胺,并与以糖精为原料合成邻甲酸甲酯苯磺酰胺的方法对比,找出了合成邻甲酸甲酯苯磺酰胺的最佳合成工艺路线,为进一步合成磺酰脲类除草剂提供了一个经济、合理的中间体合成路线.     

盐酸二甲双胍胃漂浮缓释制剂的制备与释药过程研究

采用湿法制粒压片制备了盐酸二甲双胍胃漂浮缓释片。片剂具有良好的漂浮特性 ,药物释放可延长至 8h以上。片剂的漂浮迟滞时间随羟丙甲基纤维素质量分数的增加而降低 ,片剂密度与十八醇质量分数的关系为 :ρ =1 1 4 6 - 1 2 1 2w。采用单层桨网法对片剂的体外释放实验结果表明 ,药物的体外释放动力学符合 :Q =S[DPCP(2C0 -CP)t] 1 / 2,药物通过扩散和骨架溶蚀共同作用进行释放     

Corrosion protective bi‐layered composites of polyaniline and poly(o‐anisidine) on low carbon steel

Bi‐layered composites of polyaniline (PANI) and poly(o‐anisidine) (POA) were investigated for corrosion protection of low carbon steel (LCS). In this work, homopolymers and bi‐layers of PANI and POA were electropolymerized on LCS from an aqueous salicylate solution by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Corrosion tests were carried out in aqueous 3% NaCl solution for LCS coated with PANI, POA, bi‐layered POA/PANI (POA on top of the PANI) or PANI/POA (PANI on top of the POA) composites using open circuit potential (OCP) measurements, potentiodynamic polarization technique, and electrochemical impedance spectroscopy (EIS). The single layer of PANI and POA protected the LCS in 3% NaCl for 8 and 16 h, respectively. The bi‐layered composite coatings provide effective protection to LCS for a longer time than a single layered PANI or POA coating. However, the corrosion protection offered to LCS depends on the deposition order of polymer layers in the composite. The PANI/POA composite provides better protection to LCS against corrosion than POA/PANI coating. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

搪瓷釉配方优化设计的通用方案

本文介绍了一种由计算机实现的配方优化设计方法,并给出了一个简单的通用优化方案。经实际运行证明,该方案是一个简单可行,易于推广的通用优化方案。     

高效液相色谱法测定染发剂中对苯二胺及某些酚类物质的含量

本文采用了高效液相色谱法测定染发剂中对苯二胺、邻氨基酚、对苯二酚及间苯二酚。该法简便快速 ,检测下限分别为 0 .0 89、0 .2 5、0 .0 0 19和 0 .0 0 33毫克 /克 ,具有良好的精密度和准确度     

NdFeB永磁合金的晶粒结构缺陷模型及矫顽力机制

概述了ＮｄＦｅＢ类稀土永磁合金的晶粒结构及其缺陷模型。包括单变量连续变化模型，三变量突变模型和激活体积模型。介绍了基于不同结构缺陷模型的各种矫顽力理论，比较了他们的异同点，提出了统一结构缺陷模型的构想。     

Differential scanning calorimetric and free volume study of reactive compatibilization by EPM‐g‐MA of poly(trimethylene terephthalate)/EPDM blends

Differential scanning calorimetry (DSC) and positron annihilation lifetime measurements have been carried out to study the effect of the compatibilizer maleic anhydride grafted ethylene propylene copolymer (EPM‐g‐MA) in poly trimethylene terephthalate and ethylene propylene diene monomer (PTT/EPDM) immiscible blends. The DSC results for the blends of 50/50 and 30/70 compositions show two clear glass transition temperatures, indicating that the blends are two‐phase systems. With the addition of compatibilizer, the separation between the two glass transitions decreased, suggesting an increased interaction between the blend components with compatibilizer. At 5 wt % of compatibilizer, the separation between the T_gs reduced in both 50/50 and 30/70 blends. The positron results for the blends without compatibilizer showed an increase in relative fractional free volume, as the EPDM content in the blend is increased. This suggests the coalescence of free volume of EPDM with the free volumes of PTT due to phase separation. However, the effect of compatibilizer in the blends was clearly seen with the observed minimum in free volume parameters at 5% of the compatibilizer, further suggesting that this percent of compatibilizer seems to be the optimum value for these blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 740–747, 2006     

程序ⅥB试验老化对油品理化性能影响考察

通过对程序ⅥB发动机台架试验新油和老化油的运动黏度、摩擦系数、钙元素浓度、总酸值和总碱值等理化性能分析,考察了程序ⅥB发动机台架试验老化对油品理化性能的影响。结果表明,在程序ⅥB发动机台架试验中油品运动黏度随老化时间的增加先下降后上升;油品的摩擦系数随老化时间的增加而增大,老化初期摩擦系数增大速度较快,老化后期摩擦系数增大速度减缓;老化造成油品钙元素浓度增大,老化初期油品钙元素浓度增大较快,后期油品钙元素浓度增大速度减缓;老化造成油品总酸值增大、总碱值下降。     

气溶胶雷达比和波长指数的仿真研究

为深入研究气溶胶光散射特性,以米散射理论和粒谱分布为基础,仿真计算了多种气溶胶的雷达比和波长指数,研究了二者与入射光波长、气溶胶尺寸及复折射率之间的关系,仿真结果表明水云和雾在355 nm、532 nm和1064 nm波长的激光雷达比均约为19 sr,波长指数的绝对值很小,表明消光系数与波长之间不存在明显的依存关系.大陆型气溶胶的雷达比与其中soot型气溶胶的含量正相关,这与soot型气溶胶的强吸收性有关.大陆型气溶胶在532 nm波长的雷达比最大,在355 nm和1064 nm的雷达比相对较小.大陆型气溶胶的消光系数随波长增加而减小,其波长指数的平均值约为1.3.