染料敏化太阳电池基底的选择和工艺分析

染料敏化太阳电池是由透明导电玻璃、纳米晶TiO2多孔薄膜、电解质溶液以及镀Pt对电极构成的"三明治"式结构.染料敏化太阳电池基底的选择对DSSC电池的光电性能和成本具有重要研究价值和实用意义.本文对当前染料敏化太阳电池研究领域常用基底进行了比较和工艺分析.     

小面积染料敏化纳米薄膜太阳电池的优化研究

论述了对小面积染料敏化纳米薄膜太阳电池各个组成部分优化实验的研究,主要包括纳米TiO2多孔薄膜、染料光敏化剂、电解质、反电极及其它工艺的优化选择。通过对电池各种参数的优化和实验,获得了8.73%的光电转换效率。实验结果表明,小面积电池的实验是研究染料敏化纳米薄膜太阳电池光伏性能的一种极好的途经,将为保证大面积DSCs的光伏性能和将来的产业化打下良好的基础。     

准固态染料敏化太阳电池的制备与性能研究

以AS树脂作为聚合物凝胶电解质基体,乙腈和四氢呋喃作为混合有机溶剂制备准固态染料敏化太阳电池.经过各个组成的优化,聚合物凝胶电解质电导率(30℃)达到5.11mS·cm-1,准固态染料敏化太阳电池的光电转换效率在100mW·cm-2光强下达2.56%.通过在聚合物凝胶电解质中加入氮杂环类添加剂吡啶和1-甲基咪唑,准固态染料敏化太阳电池的光电转换效率在100mW·cm-2光强下分别提高到3.09%和3.00%.     

新型介孔碳/金属薄板对电极染料敏化太阳电池的光电性能

采用金属薄板为基材及高催化活性的介孔碳为催化材料,构建出低廉的新型对电极,考察了相应染料敏化太阳电池(DSC)的光电性能。结果表明,不锈钢304或316为基材时,能获得效率优于FTO基底介孔碳对电极且稳定性较佳的器件。特别是不锈钢316,与FTO相比,效率从5.68%增加到6.36%,增幅为12%。阻抗分析揭示,方块电阻的急剧下降是效率改善的主要原因。镍为基材时,器件具有与Pt/FTO对电极相近的效率,然而镍被电解质缓慢地择优溶解削弱了部分碳膜与基底的结合,导致稳定性下降。铝合金为基材时,铝向碳膜中扩散覆盖了部分碳颗粒表面的活性点,导致器件的效率低于1%。     

染料敏化纳米ZnO薄膜太阳电池研究进展

叙述了染料敏化纳米ZnO薄膜太阳电池的研究进展。主要讨论了电子注入、dye/Zn2 的团聚等影响染料敏化纳米ZnO薄膜太阳电池效率的关键问题。最后给出了提高此类太阳电池效率的可能途径。     

纳米晶TiO_2光阳极修饰及光电子复合效应

对染料敏化纳米晶TiO_2薄膜太阳电池的光阳极进行了不同方法的TiCl_4修饰处理,测量了各种修饰处理下的TiO_2太阳电池的光电转换性能。通过准分子脉冲激光(λ=248nm)和氙灯辐照下的开路光电压V_∝随时间的衰减关系,分别研究了单色脉冲和多色连续光激发下的染料敏化TiO_2太阳电池的光电子复合效应,从中明确了TiCl_4修饰对染料敏化TiO_2太阳电池暗电流的调制所起的重要作用。     

染料敏化纳米薄膜太阳电池TiO2薄膜的研究进展

主要从染料敏化纳米薄膜太阳电池（以下简介DSCs）的工作原理出发，分别对染料敏化纳米薄膜太阳电池中纳米多孔TiO2薄膜的最新研究和实验进行了讨论，并指出了纳米多孔TiO2薄膜研究中所存在的、影响电池效率的一些主要问题，以及可能的解决方法。     

原位刻蚀法制备TiO2纳米线阳极薄膜

采用水热法在FTO基板上制备Ti O2纳米线阵列,在此基础上,通过水热法采用HCl对该薄膜进行原位刻蚀。XRD结果表明刻蚀过程并未影响Ti O2纳米线阵列薄膜的结晶性。SEM结果表明刻蚀过程能有效降低纳米线之间的团聚程度,从而保证薄膜具有较大的比表面积。染料的吸附-脱附结果也表明,刻蚀后纳米线薄膜的染料负载能力提高了1倍,将制备的Ti O2纳米线阵列薄膜作为染料敏化太阳电池的光阳极进行光电性能研究,发现使用经过刻蚀处理光阳极的太阳电池比采用未刻蚀处理的光阳极薄膜的电池光电转换效率提高了6倍。     

新型多层太阳电池薄膜性能

Au薄膜作为新型多层太阳电池关键的组成部分,其表面染料吸附量对电池性能有很大的影响。采用亚硫酸盐电镀法制备纳米Au薄膜,利用扫描电镜研究了Au薄膜的表面形貌,利用紫外可见分光光度计研究了汞溴红在Au薄膜表面的吸附工艺和性能,并计算出Au薄膜表面的最大染料吸附量。采用亚硫酸盐电镀的Au薄膜制备出这种多层太阳电池,并测试了其光电转换效率。     

染料敏化太阳电池中TiO2有序膜的制备及应用

探讨了一种简便的制备二氧化钛有序薄膜的方法及其在染料敏化太阳电池中的应用。用合成的聚苯乙烯悬浮液,采取垂直自然沉积法和水平自然沉积法得到了聚苯乙烯胶体晶体;以垂直自然沉积法得到的聚苯乙烯胶体晶体为模板制备了纳米二氧化钛有序薄膜;用所制得的二氧化钛有序膜组装成染料敏化太阳电池,在模拟日光下进行了光电性能测试,开路电压为0.780V,短路电流密度为0.612mA/cm2。此外,还对胶体晶体模板和二氧化钛有序膜的微观结构进行表征和讨论。     

Ash-forming elements in four Scandinavian wood species. Part 1: Summer harvest

Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden.     

NEXT GENERATION ENGINEERED MATERIALS FOR ULTRA SUPERCRITICAL STEAM TURBINES

正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%.     

Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。     

新型高压共轨ECU升压模块的数字化开发与优化

为了提高喷油器电磁阀的响应速率,提出了一种基于CPLD(复杂可编程逻辑器件)应用于高压共轨ECU的数字升压模块。鉴于该升压电路结构参数多,其升压电压的恢复响应要求高等特征,基于Pspice建立了升压电路的仿真模型,研究了不同电路参数下升压模块的输出特性,全面优化了该升压模块的性能。结果显示,该升压模块的最大转换效率可以达90%以上。在柴油发动机上对ECU的试验表明,升压电压最大波动不超过10%,其恢复时间仅为1.3ms,功率管最大温升仅为41℃,满足整机运行范围内ECU的需求。     

Contents in Volume 23,2014

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Trace metal chemistry and silicification of microorganisms in geothermal sinter, Taupo Volcanic Zone, New Zealand

As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied.     

Assessment methods of material ageing using Sdobyrev''s creep rupture model

The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σ_red = σ₁ β + (1 − β)σ_i, where: σ₁-maximal principal stress, σ_i-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures.     

Production of hydrogen from sewage biosolids in a continuously fed bioreactor: Effect of hydraulic retention time and sparging

Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H₂ kg⁻¹ VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min⁻¹ successfully prevented a decline in hydrogen production and resulted in a yield of 27.0  L H₂ kg⁻¹ VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production.