迎头色谱法测ZSM—5分子筛的表面酸性

本文介绍了用有机碱的迎头色谱法配合TPD技术测定ZSM-5分子筛催化剂的表面酸性,以甲醇转化高辛烷值汽油的HZSM—5催化剂为例,观察到了它有与Y型及氢丝光沸石不同的高温部分强酸峰,因此它能使甲醇转化成高辛烷值汽油,随着催化剂再生次数的增加,酸量逐渐减少,强酸峰顶温度向低温方向转移,油品中芳烃含量也逐渐降低。这一方法的建立,为进一步了解在HZSM—5催化剂上甲醇转化成高辛烷值汽油的机理提供了有价值的信息。     

改性淀粉用作混凝土减水剂的研究进展

综述了混凝土减水剂的发展状况和目前存在的问题,介绍了淀粉的结构、改性淀粉如羧甲基淀粉、磺化淀粉和淀粉丁二酸单酯等的合成方法,以及改性淀粉用作混凝土减水剂的分散机理。     

氯化聚乙烯橡胶的生产应用及发展前景

氯化聚乙烯是通过聚乙烯的氯取代反应制得的一种重要的高分子材料．也可视为乙烯、氯乙烯和1,2-二氯乙烯的三元共聚物。根据其性质和用途,可分为树脂型产品（CPE）和橡胶型产品（CM橡胶）两大类。     

中药废水的Fenton法处理试验

中药废水成分复杂、有机物含量高、色度深、生物毒性性大,其处理是工业废水难点之一。研究了Fentoni法处理中药废水的实验过程,分析了反应时间、H2O2、Fe2＋及H2O2与Fe2＋的浓度比不同条件对处理效果的影响。     

国外空间太阳能热动力发电系统发展及建议

空间太阳能热动力发电系统作为一种新型的空间供电方式，在费用上和性能上已经显示出了很大的优势，有可能成为未来的空间供电方式。国外对于它的研究已经超过40年。通过介绍空间太阳能热动力发电系统的工作原理和技术发展，并且与其它电源系统、主要是光伏系统进行技术比较，显示出这种供电方式的的较大优势。重点介绍了NASA 2kW空间太阳能热动力发电系统地面样机的部件、结构和试验。根据国外研究经验，提出了空间太阳能热动力发电系统研究的建议。     

Research on performance of centrifugal pump with different-type open impeller

To investigate the influence of impeller type on the performance and inner flow of centrifugal pump, the numeri- cal simulation and experimental research were carried out on the same centrifugal pump with straight-blade and curved-blade open impeller. Based on SIMPLEC algorithm, time-averaged N-S equation and the standard k-e turbulence model, the numerical results are obtained. The pressure distribution in the different type impellers is uniform, while the low pressure area in straight-blade inlet is larger. The vortexes in the passage of impeller exist in both cases. Relative to curved-blade impeller, there are larger vortexes in most of the flow passages except the passage near the tongue in straight-blade impeller. Also some small backflow regions are found at the blade inlet of two impellers. The characteristic curves achieved by numerical simulation basieaUy agree with those by experiment, and straight-blade open impeller centrifugal pump has a better hydraulic performance.     

TiO2/CdS composite hollow spheres with controlled synthesis of platinum on the internal wall for the efficient hydrogen evolution

Solar driven semiconductor photocatalytic water splitting to produce hydrogen is an extremely charming process by storing photon energy in chemical bonds. In the present study, composite semiconductor TiO₂/CdS was structured into uniform and porous double-shelled hollow sphere with cocatalyst platinum selectively loaded onto the internal wall. The SEM, TEM, STEM, XRD, BET and EDS elemental distribution etc. were employed to evidence the formation of the targeted photocatalyst. It was demonstrated that the material has a high efficiency of visible-light-driven hydrogen evolution (296 μmol·h⁻¹/10 mg) with an apparent quantum efficiency (QE) of 14.5% at wavelength of 420 nm. Comparative experiment analysis and time-resolved infrared absorption study suggested that the high photocatalytic activity of the catalyst is attributed to the vectorial electron transfer (CdS → TiO₂ → Pt) and the spatial separation of reduction and oxidation active surfaces achieved by the special morphology.     

High- and low- temperature behaviors of La0.6Sr0.4Co0.2Fe0.8O3−δ cathode operating under CO2/H2O-containing atmosphere

High- and low- temperature behaviors of La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF) cathode for solid oxide fuel cells operating under CO₂/H₂O-containing atmosphere are investigated. LSCF shows different stability against CO₂ and H₂O at high and low temperature. LSCF has excellent electrochemical performance and high stability against the corrosion of CO₂ and H₂O at 750 °C due to weak reactivity of LSCF with CO₂. LSCF shows a serious degradation at 600 °C under operation with O₂–CO₂(2.83%)–H₂O(2.64%), which is ascribed to the impeded oxygen activation and oxygen surface diffusion by surface carbonates and SrCO₃ phases on LSCF surface. Under CO₂(5%)–H₂O(2.81%)–He, LSCF reacts with CO₂ to yield SrCO₃ phases in 400–680 °C, and H₂O aggravates the chemical reaction between CO₂ and LSCF. Taking into account of SrCO₃ phase formation on LSCF, LSCF cathode is stable under operation with O₂–CO₂(2.83%)–H₂O(2.64%) in 680–800 °C, whereas it is unstable below 680 °C. LSCF can be subject to degradation caused by CO₂ and H₂O in air during long-term operation below 680 °C.     

Fabrication of ZnO/SrTiO3 nanoarrays and its photoelectrochemical performances

The ZnO/SrTiO₃ nanomaterials were fabricated by a chemical conversion hydrothermal method in order to utilize the high electron transfer rate of one-dimensional ZnO nanorods and photocatalytic activity of SrTiO₃. The technological parameters, such as TiO₂ sol concentration, TiO₂ sol dipping cycle, Sr(NO₃)₂ concentration and reaction temperature, were investigated in the synthetic process and the reaction mechanism of the ZnO/SrTiO₃ nanomaterials was proposed. A photocurrent density of 7.53 mA/cm² was obtained for the as-prepared ZnO/SrTiO₃ photocatalyst, attributed to its improved absorption spectrum and appropriate nanostructure, which indicates a potential application in photoelectrochemical water splitting.     

城市生活垃圾焚烧发电CDM项目案例分析

本文分析评价了我国城市生活垃圾的产生量、资源量、国内外垃圾焚烧技术应用状况、制约我国城市生活垃圾焚烧技术应用的主要因素以及垃圾焚烧发电技术应用潜力。本研究以城市生活垃圾焚烧发电技术为案例,基于三个基准线,应用增量成本分析方法,计算了垃圾焚烧发电作为CDM(清洁发展机制)项目的单位碳减排成本并对其进行了敏感性分析,提出城市生活垃圾焚烧发电技术应作为我国与发达国家进行CDM项目合作的优先技术领域。