TiO2-SiO2复合半导体气凝胶制备及光催化活性研究

ＴｉＯ２－ＳｉＯ２复合半导体气交是一种新型纳米光催化氧化剂。本文以正硅酸乙酯、钛酸丁酯为原料,用溶胶－凝胶法经超临界干燥制备出了ＴｉＯ２－ＳｉＯ２复合半导体气凝胶。研究了ＴｉＯ２：ＳｉＯ２不同配比对溶胶－凝胶过程的影响;用ＢＥＴ、ＸＲＤ、ＳＥＭ、ＴＥＭ等测试方法对其结构进行了表征;以苯酚为探针考察了ＴｉＯ２－ＳｉＯ２复合半导体气凝胶的光催化氧化活性,并与普通锐钛矿型钛白粉光催化剂进行了对比结果表明     

以正钛酸为原料制备纳米TiO2光催化剂

以正钛酸为原料,通过直接水解法制备纳米ＴｉＯ_２;并对样品分别进行了差热分析、Ｘ射线衍射分析和透射电子显微镜分析．结果表明,样品粒子为混晶型纳米ＴｉＯ_２,单分散性良好,粒径分布范围狭窄．当它应用于阴离子表面活性剂十二烷基苯磺酸钠的光催化降解时,与Ｐ－２５光催化剂相比,具有较好的催化活性．同时,我们用Ａｌ_２Ｏ_３陶瓷膜回收纳米ＴｉＯ_２循环再利用;这为纳米ＴｉＯ_２在环保方面的大规模应用创造了条件．     

铁、铬离子掺杂对TiO_2薄膜光催化活性的影响

采用溶胶－凝胶法在釉面砖表面制备了均匀的ＴｉＯ２薄膜,并研究了铁、铬离子掺杂对ＴｉＯ２光催化性能影响．对罗丹明Ｂ的光降解实验表明,适量的铁、铬离子掺杂均可提高ＴｉＯ２薄膜的光催化活性,铁离子的掺杂效果明显高于铬离子,而铬离子的掺杂方式影响ＴｉＯ２薄膜的光催化活性,这主要基于它们不同的掺杂机理     

Y^3＋掺杂TiO2复合粒子的光催化活性研究

以钛酸丁酯和氧化钇为原料,采用溶胶－凝胶法研究了Ｙ＾３＋掺杂对ＴｉＯ２光催化活性的影响,通过红外光谱（ＩＲ）分析了ＴｉＯ２复合粒子的结构,结果表明：Ｙ＾３＋掺杂能够显著提高ＴｉＯ２粒子的光催化活性,当掺杂比为１００∶１．５（Ｙ＾３＋外加１．５％）时光催化活性最高,分析了Ｙ＾３＋掺杂ＴｉＯ２粒子光催化活性提高的原因。     

纳米TiO2光催化降解水中有机污染物的研究与发展

光催化降解水中有机污染物是一项新兴的颇有发展前任的废水处理技术,纳米Ｔｉｏ２因其活性高,稳定性好而在该领域广泛被用作光催化剂。本文系统介绍了纳米ＴｉＯ２的制备,光催化降解水中有机污染物的机理,动力学规律及其研究现状和发展方向。     

溶胶—凝胶法制备TiO2／Pt／glass纳米薄膜及其光电催化性能

本文采用Ｓｏｌ－ｇｅｌ法制备了ＴｉＯ２／Ｐｔ／ｇｌａｓｓ纳米光催化薄膜，并进行了结构和乐电催化性能的测试。薄膜对染料溶液的光电催化降解结果表明，当输入正向偏压后，ＴｉＯ２／Ｐｔ／ｇｌａｓｓ薄膜的光催化性能有一定提高，且随着偏压增大而增强。同时，薄膜的中间层Ｐｔ及光源强度对薄膜的光电催化活性也有较大影响。     

纳米TiO2粉体的制备及应用进展

纳米ＴｉＯ２粉体在催化、功能陶瓷、化妆品、化纤及环境工程等领域具有广阔和潜在的应用。本文根据国内外研究者的报道及作者近期对纳米ＴｉＯ２的制备研究,介绍了纳米ＴｉＯ２的合成及应用。     

纳米 TiO2的高分子"锚定位"包覆

通过多组分溶液的原位合成方法,成功地制备了ＴｉＯ２／聚苯乙烯－马来酸酐（ＰＳＭＡ）纳米复合材料．红外普图（ＩＲ）分析了这种材料的化学构成,证明纳米ＴｉＯ２与高分子是以共价键的形式存在．随着反应条件的改变,透射电镜（ＴＥＭ）观察到了纳米ＴｉＯ２在复合物中有规律的形貌变化．综合实验结果,提出高分子“锚定位”包覆的作用模型,形象地说明了这种材料以三维网络、纳米晶ＴｉＯ２微相分离的形式存在,同时ＴｉＯ２颗粒的团聚几率在相当大程度上得以降低．结合Ｘ射线衍射,还确定出了复合物中纳米ＴｉＯ２的锐钛矿型结构．     

硬脂酸法制备纳米TiO_2及微结构控制

采用硬脂酸法制备了不同掺杂量的ＴｉＯ２纳米晶．通过ＦＴＩＲ、ＸＲＤ和ＴＥＭ等实验手段对所得纳米ＴｉＯ２进行分析和表征,并对反应历程进行了初步探讨．实验结果表明,利用硬脂酸法,金红石型ＴｉＯ２能在５００℃获得,掺杂Ｎａ＋和Ｋ＋后则得到锐钛矿型ＴｉＯ２,且随着掺杂量的增加,ＴｉＯ２的粒径减小．     

纳米级ZnO—TiO2复合粉体的制备及其性能表征

利用ＺｎＳＯ４和Ｔｉ（ＳＯ４）２为原料,在合成纳米ＴｉＯ２粉体的基础上,将ＴｉＯ２微粉分散在（ＮＨ４）２ＣＯ３溶液中,进一步将ＺｎＣＯ３的形成沉淀出来,于３００℃煅烧２ｈ,即可制得纳米级ＺｎＯ－ＴｉＯ２复合粉体,其粒径约３０－９５ｎｍ。     

环保型TiO2薄膜玻璃性能的研究

采用溶胶－凝胶法在玻璃表面制备了TiO2薄膜和掺杂铈或镧TiO2薄膜，利用高效液相色谱仪（HPLC）、紫外－可见分光光度计、扫描电镜（SEM）等测试手段，研究了不同气氛条件下热处理的TiO2薄膜对油酸光催化降解的影响，TiO2薄膜中掺杂稀土铈或稀土镧对油酸光催化降解的影响，薄膜内TiO2晶粒的分布及形态，薄膜表面化学稳定性等。结果表明空气气氛下处理的TiO2薄膜光催化效率最高。掺杂铈或镧有利于提高TiO2薄膜的光催化降解效率，涂层有利于提高玻璃的化学稳定性，但提高的程度不一。     

Brain tumor detection and diagnosis using ANFIS classifier

In this article, the segmented brain tumor region is diagnosed into mild, moderate, and severe case based on the presence of tumor cells in the brain components such as Gray Matter (GM), White Matter (WM), and cerebrospinal fluid (CSF). The modified spatial fuzzy c mean algorithm is used to segment brain tissues. The feature Local binary pattern is extracted from segmented tissues, which is trained and classified by ANFIS Classifier. The performance of the proposed brain tissues segmentation system is analyzed in terms of sensitivity, specificity, and accuracy with respect to manually segmented ground truth images. The severity of brain tumor is diagnosed into mild case if the segmented brain tumor is present in the grey matter. The severity of brain tumor is diagnosed into moderate case if the segmented brain tumor is present in the WM. The severity of brain tumor is diagnosed into severe case if the segmented brain tumor is present in the CSF region. The immediate surgery is required for severe case and medical treatment is preferred for mild and moderate case.     

基于双寡头竞争的航空客运模糊销售定价决策

针对近年来航空公司机票销售领域流行的模糊分销模式,利用Hotelling模型建立了季末单一模糊销售以及直销与模糊销售共存的双寡头竞争模型,求解供大于求和供小于求下两种销售模式各利益主体的均衡价格及收益,旨在发现哪种销售模式更有利于提高航空公司的收益。研究表明,当市场竞争激烈时,模糊分销模式存在,且季末共同销售策略下航空公司的期望总收益高于单一模糊销售,同时模糊中介商有动力实施该模式,凸显了双渠道同期销售对市场需求的引导作用。该研究结果可为航空公司竞争环境下的均衡定价决策和销售模式选择提供理论参考。     

Influence of vanadium on grain boundary segregation of phosphorus in iron and iron-carbon alloys

The influence of vanadium on grain boundary segregation of phosphorus has been studied in iron and iron-carbon alloys by means of fracture experiments in a scanning Auger microprobe. The emphasis here is to study the effects of vanadium on the interaction processes operative under circumstances when structure in the interior of the grain (in the present case carbide formation) and grain boundary segregation form simultaneously. It is emphasized that to predict and analyse the behaviour of an alloy, it is important to consider atomic interactions both at the grain boundaries and in the grain interior and that between the constituents and the grain boundaries. The study suggests that the principal determining factor in the scavenging or retardation of migration of phosphorus to the grain boundaries is whether vanadium is present in the combined form (say, carbide) or is available in solid solution form. When vanadium is present in solid solution form, grain boundary segregation of phosphorus is low because of the chemical interaction of vanadium and phosphorus. However, as carbon is increasingly introduced in the alloy, vanadium now preferentially reacts with carbon in view of higher interaction for carbon as compared to phosphorus. A consequence of this is the increase in the grain boundary concentration of phosphorus. In such a situation the presence of excess carbon in addition to what is stoichiometrically required to precipitate the entire vanadium as vanadium carbides, serves as a palliative with regard to the reduction in the intergranular concentration of phosphorus. This palliative behaviour is explained in terms of the sitecompetition model. An effort is also made to examine the behaviour of segregating elements in terms of whole range of probable interactions (both at the grain boundaries and in the grain interior) and chemical interaction energies.     

微合金钢的研究现状及发展趋势

微合金钢是近年来迅速发展起来的具有高性能的钢材品种之一,被广泛用于各个工业部门,是现代钢铁工业中的主力产品.简要介绍了微合金钢的属性,综述了国外微合金钢的研究现状,着重讨论了国内微合金钢的研究现状,总结了宝钢、鞍钢、攀钢和国内科研机构微合金钢的发展现状,并论述了国内外微合金钢未来的发展趋势.     

太平洋牡蛎(Crassostrea gigas)鳃氯细胞的超微形态研究

利用透射电子显微镜研究了太平洋牡蛎鳃氯细胞的超微结构。氯细胞主要分布于鳃小叶的基部,呈口袋状,细胞个体较大,在鳃表面有一凹隐的分泌腔。细胞中,细胞核多位于基部,体积较小;具有发达的微细小管系统,但小管的分支程度低;线粒体数量较少且结构不够发达;可见少量的高尔基体,未见内质网。鳃氯细胞是太平洋牡蛎鳃渗透压调节的重要细胞系统。     

A fuzzy logic-controlled thermal process for simultaneous pasteurization and cooking of soft-boiled eggs

A fuzzy logic-based design of control for a unique thermal process in the food industry is presented. Products of the thermal process are pasteurized soft-boiled eggs. The function of temperature vs. time is unique in its shape and in its required precision, since the constraints of pasteurization and cooking of soft-boiled eggs are technically contradictory. Both processes can coexist only in a quite narrow temperature range, which is a nonlinear function of egg processing time. Precision in temperature control is essential. The thermal process is implemented in an apparatus that presents a novelty on the market of industrial kitchen appliances.A precondition for the present work was simulation of thermal energy propagation in hens' eggs of different sizes and ages. A function of temperature vs. time for the media in which eggs are immersed was defined. The function is piecewise linear in time, with horizontal and near vertical sections and abrupt transitions between them.The process is patented and the quality of pasteurization is certified by the corresponding institutes. The result is pasteurized soft-boiled eggs for consumption in hospitals, schools and hotels. The presented fuzzy control implementation of the thermal process meets the requirements, and thus the implication is that the design and implementation of temperature control based on fuzzy logic is suitable for processes where precision is required.     

'Arching' effect in elastic polycrystals: implications for the variability of fatigue lives

ABSTRACT The paper deals with a study of heterogeneous stress and strain distribution in polycrystals in relation with elastic anisotropy of grains. A similitude with the arching effect widely studied in granular materials is proposed and this concept is extended to heterogeneous polycrystals in which the load transfer is not binary in the way it is in granular media but may vary significantly and suddenly from one grain to another according to the crystal orientation to the load direction. Experiments and 3D finite element analyses show that though the individual orientation of grains is random, the strain and stress distribution is not. A network is formed inside the polycrystal whose scale is larger than the grain size. The load percolation network consists in heavily loaded links whose direction is coincident with the direction of the principal stresses. So, the typical scale for the variability of the local stresses is not the grain size but the size of the load percolation network. Since this scale is found to be rather large in particular for iron, zinc and copper, this effect should contribute significantly to the variability of the fatigue lives of notched vs. smooth components.     

铝镁合金熔炼中气体保护法的动力学研究

在铝镁合金熔炼过程中,因为镁的化学性质活泼,导致合金的氧化、烧损现象十分严重,不仅降低了合金中镁的收得率,而且造成了巨大的经济损失.为了达到阻燃目的,国内经常采用熔剂法,而目前在国外用的较多的则是气体保护法.本实验对气体保护法进行了研究,建立了相应的动力学曲线规律,并对温度因素的影响进行了探讨,所得实验结论对生产实践具有一定的指导作用.     

火电厂螺杆式空压机余热利用方案及经济性分析

火电厂中的空气压缩机运行过程中,空气得到强烈压缩,这时电能转换为机械能,同时空气温度也骤然上升,通常压缩后的空气通过冷却系统冷却后送入储气罐备用。如果将这部分热量加以回收利用,企业能耗会明显下降,起到良好的经济、环境和社会效应。针对清河电厂6台250kW空压机组压缩空气系统,开展了余热回收方案设计,回收的热量用于提供生活所需热水,同时进行了经济性分析。结果表明,该余热回收系统节能效果显著,项目投资回收期仅8个月左右,每年能够节约标准煤718t。