Fabrication and properties of composites from BST and polypropylene-graft-poly(styrene-stat-divinylbenzene)

In this work, ceramic–polymer composites were fabricated from barium strontium titanate powder (BST) and polypropylene-graft-poly(styrene-stat-divinylbenzene) (ER) using a twin-screw extruder. The compounding process was characterized by rheological measurements. The effects of volume loading of BST on dielectric and mechanical properties were investigated. The dielectric properties were measured as a function of frequency and BST loading. For example, the relative permittivity and loss tangent (tan δ) of the BST–ER composites at 1 GHz were gradually increased from 2.4 and 0.0001 to 28.5 and 0.0085, respectively, as the loading was increased from 0 to 50.5 vol.%. Stearic acid (StA) was used as a surface-modifier of the BST. With an approximate surface coverage of 83%, an improvement in processability and a slight increase of the permittivity was observed, while tan δ remained low. The excellent dielectric characteristics of these composites, with high permittivity and low tan δ, make them attractive novel electronic materials for high frequency applications.     

The stability of illuminated p-GaInP2 semiconductor photoelectrode

Thin p-GaInP₂ films were tested 24 h in pH1 NH₄NO₃ solution at AM 1.5 G, and compared to that tested in 3 M H₂SO₄. Optical, SEM and EDX investigations confirmed that the surface of the tested sample in pH1 NH₄NO₃ was kept almost as that of an as-received one, while the sample tested in 3 M H₂SO₄ experienced extensive corrosion via selective dissolution of Ga. ICP analysis confirmed the very low dissolution of p-GaInP₂ in pH1 NH₄NO₃ solution, compared to that in 3 M H₂SO₄. The GaInP₂ sample tested in pH1 NH₄NO₃ solution had an XPS depth profile almost identical to that of an as-grown sample, we speculate that absorbed NH₃ on the semiconductor surface could be responsible for the observed corrosion inhibition. Thus, the p-GaInP₂ should last much longer when working in pH1 NH₄NO₃ solution, due to this inhibiting effect. This result shows promise toward meeting US DOE's 2013 goal of 8% STH efficiency for 1000 h duration.     

浅论市政施工企业的集约化项目管理

近年来我国经济增速放缓,基础建设领域投资规模下降,市政工程施工行业市场竞争更加激烈,工程项目施工利润越来越薄,为应对市场形势的变化,市政施工企业转变以往单纯依靠规模效益求发展的粗放型经营管理方式已势在必行。实施集约化项目管理,是施工企业经营管理全面转型升级的一种有效途径和方式。笔者从市政工程项目管理工作实践出发,阐述了市政施工企业集约化项目管理方面的一些观点和看法。     

国产催化剂在50dam3/h制氢装置中的应用

介绍了国产催化剂HP-3,JX-5A,JX-4C,Z417/Z418和KBL-101在中国石油天然气股份有限公司锦西石化分公司50 dam3/h制氢装置的首次组合应用情况,并针对装置的设计和实际的操作条件、产品质量和总能耗等方面进行了对比分析.结果表明:①该氢气设计纯度为99.90％(摩尔分数),而实际纯度为99.56％,比设计值低0.34百分点,实际产品中甲烷与氮气的摩尔分数比设计值略高0.34百分点,一氧化碳与二氧化碳的实际值比设计值低,说明变压吸附过程设计合理;②制氢设计总能耗为55 083.2 MJ/t,实际总能耗47 224.6 MJ/t,两者相差不大,其中燃料气单耗占制氢装置总能耗比例较大,而实际燃料气单耗比设计燃料气单耗低7 858.6 MJ/t.该装置实际生产参数与设计参数一致,装置设计合理,满足生产要求.     

Improvements and Modifications to Room‐Temperature Fabrication Method for Dielectric Li2MoO4 Ceramics

Dielectric properties of lithium molybdate disks fabricated by moistening water‐soluble Li₂MoO₄ powder, compressing it, and postprocessing the samples at 120°C, were improved by the optimization of powder particle size, sample pressing pressure, and postprocessing time. It appeared that the postprocessing temperature of the Li₂MoO₄ ceramics could be chosen so as to be applicable to the associated integrated materials as long as the postprocessing time was adequately adjusted to ensure the removal of the residual water. In addition, the dielectric properties of Li₂MoO₄ ceramic were modified with an inclusion of suitable additives. For example, at 1 GHz the relative permittivity of Li₂MoO₄ disks fabricated at room temperature and postprocessed at 120°C was increased from 6.4 to 8.8 with an addition of 10 vol% of rutile TiO₂ and to 9.7 with an addition of 10 vol% of BaTiO₃. At the same time the loss tangent value increased from 0.0006 to 0.0014 and to 0.011, respectively.     

Graphene nanosheets-poly(o-aminophenol) nanocomposite for supercapacitor applications

Graphene nanosheets-poly(o-aminophenol) (POAP/GNS) nanocomposite was fabricated on a platinum surface by potential cycling. Voltammograms of the POAP/GNS/Pt electrode showed an excellent capacitive behavior accompanied with a redox transition with a mid-peak potential of 295 mV. The POAP/GNS nanocomposite displayed a specific capacitance as high as 281.1 F g⁻¹ at 0.1 A g⁻¹ which is almost three times higher than that of pure graphene. The specific energy and power of the nanocomposite material were 25.0 Wh kg⁻¹ and 34.8 W kg⁻¹, respectively. The nanocomposite retained more than 99% of the initial capacitance after 1200 charge/discharge cycles.     

村镇苦咸水源安全饮用淡化方法比较

对可能适用于村镇苦咸水淡化的反渗透法、膜蒸馏法、盘式蒸馏法和降膜蒸发法进行了比较,综述了各种方法的研究进展,对比了各种方法的优缺点,分析了各种方法在村镇的适应程度,并预测了村镇未来苦咸水淡化方法的发展趋势.     

真空钙热还原法制备金属钛粉的研究

在真空炉中(30~40 Pa)1273 K下,将物料放入螺纹密封的石墨坩埚中进行不同时间下的还原反应。本文采用热力学分析及X射线衍射、扫描电子显微镜及能量弥散X射线谱等方法与手段,系统研究了金属钙(Ca)与反应器中的氧气(O2)、氮气(N2)、二氧化钛(TiO2)的反应和还原时间及还原产物的预处理对得到金属钛粉(Ti)的影响。通过热力学研究,在温度低于钙的熔点(1115 K)时,密封容器内的O2与Ca的反应及N2与Ca的反应满足反应发生的热力学条件。当温度达到1273K时,Ca的饱和蒸气压p*≈p系,有利于整个气固反应进行。实验研究表明,在还原反应发生前,反应器内的O2,N2与Ca反应完全。将在1273 K下还原时间为4 h得到的还原产物在酸洗前真空挥发处理还原产物表面大量的Ca时,金属单质Ti再次被氧化成低价氧化物,最终得不到金属Ti粉。将反应时间延长至6 h时,酸洗过滤后得到形状不规则、纯度达到98.64%的Ti粉。     

Study on Modified Y Zeolites and Their Behaviors in Selective Adsorptive Desulfurization of FCC Gasoline （II）

Ce (Ⅲ) Y zeolite was prepared by liquid-phase ion-exchange of NaY with 0.1 mol/L Ce(NO3)3 solution at 100℃ for 4 h. After calcining the resultant Ce (Ⅲ) Y zeolite at 550℃in air, Ce (Ⅳ) Y zeolite was obtained. Desulfurization of FCC gasoline was studied by selective adsorption with Ce (Ⅳ) Y zeolite. The results showed that Ce (Ⅳ) Y zeolite can remove thiophene via d-complexation directly, while thiophene and Ce (Ⅳ) can form stable chemical bonds (sulfur-metal bonds) that can enhance the capability of Ce (Ⅳ) Y zeolite for adsorption of thiophene.