Nanocrystalline TiO2 photosensitized with natural polymers with enhanced efficiency from 400 to 600 nm

TiO₂ sensitization for solar applications requires not only efficient but also stable and inexpensive sensitizers. Different condensed tannins extracted from bark wastes of tropical wood trees were studied as possible sensitizers of TiO₂. These natural polymers adhere strongly to the TiO₂ even from aqueous solutions. Absorption spectra are presented for 1 mM aqueous sensitizing solutions prepared with lyophilized condensed tannins which absorb light in the visible range. Spectral photocurrent measurements and I–V characterization show that no bias is required for electron injection to the TiO₂ from all studied condensed tannins. Incident photon to current efficiency (IPCE) analysis indicates that surface complexation originates absorption bands with different electron injection efficiencies. These play a dominant role in determining IPCE spectral shape. We propose that surface modification by the sensitizer changes the surface trap density, thereby decreasing recombination losses.     

The effect of nitrogen oxides in air on the performance of proton exchange membrane fuel cell

The effects of NO_x on the performance of proton exchange membrane (PEM) fuel cell were investigated through the introduction of a mixture containing NO and NO₂, in a ratio of 9:1, into the cathode stream of a single PEM fuel cell. The NO_x concentrations used in the experiments were 1480 ppm, 140 ppm and 10 ppm, which cover a range of three orders. The experimental results obtained from the tests of durability, polarization, reversibility and electrochemical impedance spectroscopy (EIS) showed a detrimental effect of NO_x on the cell performance. The electrochemical measurements results suggested that the impacts of NO_x are mainly resulted from the superposition of the oxygen reduction reaction (ORR), NO and HNO₂ oxidation reactions, and the increased cathodic impedance. Complete recovery of the cell performance was reached after operating the cell with clean air and then purging with N₂ for hours.     

低温电解的节能实验研究

本文以中国铝业河南分公司电解厂85kA中间点式下料预焙槽为研究对象，通过6个月的低温电解实验，改善“四低一高”(低电解温度、低分子比、低氧化铝浓度、低效应系数和高极距)技术条件，优化工艺技术条件配置，降低分子比和电解温度，维护炉膛的规整，维护电解槽工作电压的稳定，规范员工作业标准，达到提高电流效率、降低电耗的节能效果。     

Local Strain Measurement within Tendon

Abstract:  Tendon is a dense connective tissue, responsible for transmitting the forces generated by muscles to the skeleton. It is composed of a hierarchical arrangement of crimped collagen fibres, interspersed with proteoglycan matrix and cells, known as tenocytes. During physiological loading, tendons are subjected to strains in the region of 5–6%, which result in the straightening and realignment of the collagen fibres, generating variable local strain fields within the tendon. This study demonstrates a technique for analysing local strains within viable tendon explants, during both loading and unloading of the tissue. Samples were strained in a custom-designed rig, allowing real-time visualisation of cell nuclei, used as local discrete markers, on a confocal microscope. Results indicated that local strains within the fascicle are smaller than the applied strains, never exceeding 1.2%, even at 8% gross applied strain. By contrast, the sliding of adjacent collagen units was recorded at each strain increment in this study, reaching a mean maximum of 3.9% of the applied displacement. Loading–unloading studies indicated that sliding behaviour is reversible up to strains of 5%, and provides the major extension mechanism within the rat-tail tendon. This technique can be extended to further analyse shearing behaviour within the matrix.     

Manufacturing method for monolithic dye-sensitised solar cells permitting long-term stable low-power modules

A manufacturing technique for monolithic dye-sensitised solar cells is presented. Encapsulated modules designed for indoor low-power applications have been prepared using industrial methods and equipment. Under certain conditions (light intensity <5000 lx, temperature between –10°C and 50°C, and relative humidity of appr. 50%), the modules have performed well and shown excellent long-term stability. Moreover, modules withstand illumination in combination with storage at 100% relative humidity. However, a certain degradation of the module performance takes place at illuminations exceeding 5000 lx and temperatures exceeding 50°C.     

汽车代用燃料的应用和发展

评述了汽车代用燃料的现状和未来，压缩天然气和液化石油气将率先大量使用，其次是醇燃料，合成燃料和二甲醚将主要用于某些混合动力车，燃料电池因为能源效率高是最有吸引力的车用能源，将于2010-2015年开始在汽车上实际使用，我国石油工业在提升汽油和柴油质量的同时，应与汽车工业联手开发代用燃料，特别要注意发展燃料电池技术。     

“四低一高”工艺在85kA预焙槽的应用与优化

本文介绍了“四低一高”(低电解温度、低分子比、低氧化铝浓度、低阳极效应系数、高工作电压)工艺技术条件在85kA预焙槽上的应用与优化,实验证明“四低一高”工艺需要针对具体槽型进行优化设计,适宜的技术条件对提高电流效率、降低直流电耗,节能效果显著。     

工业炉燃烧系统应用技术探讨

燃烧及其控制技术是各种火焰炉技术核心，强调高水平燃烧系统应对燃烧全过程进行控制，着重对燃烧系统点火、火焰监测、空燃比比例调节、燃烧过程各参数监控、炉温自动控制等各个方面内容进行了讨论介绍，最后用某天然气加热炉燃烧系统原理图及应用效果进行实例说明。     

冠心病患者循环血中内皮细胞、内皮素和6－酮－前列环素F_（1a）的动态变化及意义

以循环内皮细胞（ＣＥＣ）作为血管内皮细胞（ＶＥＣ）损伤的指示物，以血浆内皮素（ＥＴ）和前列环素（ＰＧＩ２）反映ＶＥＣ的功能变化，对８５例冠心病患者与３０例正常人进行对比研究，并对５０例不稳定型心绞痛及２０例急性心肌梗塞进行了动态观察．结果表明：冠心病外周血中ＣＥＣ、ＥＴ明显升高（Ｐ＜０．００１），ＰＧＩ２明显下降（Ｐ＜０．００１），尤以不稳定型心绞痛和急性心肌梗塞更显著，与病情的严重程度相一致．提示冠心病ＶＥＣ损伤，以及它所分泌的内皮源性舒缩因子失平衡参与了冠心病的病理过程。