Monolithically-integrated BiVO4/p+-n GaAs1-xPx tandem photoanodes capable of unassisted solar water splitting

Monolithically-integrated tandem photoanodes were fabricated on substrates consisting of epitaxial n-GaAs_1-xP_x (x ? 0.32) grown on n⁺-GaAs wafers. A p⁺-n junction photovoltaic (PV) cell was first formed by zinc diffusion into the n-GaAs_0.68P_0.32 from a deposited ZnO coating. After diffusion the ZnO serves as a transparent electrical contact to the resulting p⁺-GaAs_0.68P_0.32 surface layer. Transparent, conducting SnO₂:F provides chemical and mechanical protection for the ZnO and the underlying PV cell, and it electrically connects this cell to a top BiVO₄ photocatalyst layer. In some photoanodes, a WO₃ thin film was interposed between the SnO₂:F and BiVO₄. All oxide coatings were produced by ultrasonic spray pyrolysis except WO₃, which was spin coated. Unassisted (unbiased) solar water splitting was achieved, with a solar-to-hydrogen efficiency approaching 2%, without addition of any co-catalyst to the BiVO₄ surface. This work can provide insights to other researchers regarding scalable, low cost approaches for the planar monolithic integration of oxide photoanode materials with PV cells to create new tandem devices.     

Determination of total non-sulphonated aromatic amines in tartrazine, sunset yellow FCF and allura red by reduction and derivatization followed by high-performance liquid chromatography.

Free and bound non-sulphonated aromatic amines (NSAA) are determined in the food colours tartrazine, sunset yellow FCF and allura red. After reduction of the bound amines with sodium dithionite, the NSAA are extracted into chloroform, then transferred to aqueous acid solution, diazotized with sodium nitrite and coupled with 2-naphthol-3,6-disulphonic acid, disodium salt (R-salt). Reversed-phase ion-pair liquid chromatography and an absorbance detector at 512 nm are used to analyse the coloured derivatives. Samples of dyes were spiked with known amounts of aniline, 1-naphthylamine, 2- and 4-aminobiphenyl, 4-aminoazobenzene, benzidine, p-cresidine or 4-nitro-p-cresidine bound to R-salt. Recoveries averaged 90% in tartrazine, 65% in sunset yellow FCF and 71% in allura red. Detection limits ranged between 2 and 32 ng/g. A survey of 24 commercial samples revealed levels up to 520 micrograms/g total NSAA. The majority of NSAA are bound to the coupling compound during the manufacturing process and less than 7% remain as free amines in the dye.     

峡口水库沥青混凝土面板的施工与试验

以灌溉、防洪为主的峡口水库大坝，为沥青混凝土面板堆石坝，为研究低温抗裂性能，对沥青混凝土面板破损取样，进行了配比和多种力学性能试验，并与原面板设计指标进行了对比。由于面板经受住了－20℃以下的低温考验，其所用沥青指标、破损取样试验结果，特别是冻断低温指标，对确定水工沥青混凝土低温抗裂检验标准有重要参考价值。     

基于BOOSt结构下不连续导电模式的PFC电路

采用现代高频功率变换技术的有源功率因数校正（Power Factor Corrector,PFC)技术是解决高频开关变换器谐波污染的有效手段。与传统的PFC电路相比，有源PFC电路的输入电流接近正弦波且与输与电压同相位，能有效抑制电流波形畸变和谐波，因此避免了对同一电网设施的干扰。在PFC电路中，Boost变换器是研究和应用得最多的一种变换器。本文着重分析了Boost电路在不连续导电模式状态下，PFC电路的临界条件，对实际电路结构的设计有很好的指导意义。     

Salt-water up-coning during extraction of fresh water from a tropical island

Rainwater can collect in a lens-shaped region within the rock of a tropical island, and may be separated from the underlying salt water by a sharp interface. This paper presents a nonlinear theory for determining the shape of this interface. The island is assumed to be saturated with rain, and provision is made for the outflow of rain-water through the sides of the island. The effect of a bore well on the shape of the interface is investigated, and the problem is solved using a spectral method. An integral-equation method is also presented for the case when the island has infinite width.     

Implementation of a mechanics-based system for estimating the strength of timber

The most accurate way of determining the strength of lumber requires destructive testing. An intelligent mechanics-based lumber-grading system was developed to provide a better estimation of the strength of a board nondestructively. This system processed X-ray-extracted geometric features (of 1080 boards that eventually underwent destructive strength testing) by using finite element methods to generate associated stress fields. The stress fields were then fed to a feature-extracting-processor, which produced 26 strength predicting features. The best strength predicting features were determined from the coefficient of determination (correlation r/sup 2/) between the features and actual strengths of the boards. The coefficients of determination of each feature (or combination of features), with the actual strength of the board, were calculated and compared. A coefficient of determination of 0.4158 was achieved by using a longitudinal (along the local grain angle) maximum stress concentration (MSC) feature to predict the estimated strength of lumber.     

Neurophysiological Model of the Normal and Abnormal Human Pupil

A model of the pathways controlling the size of the human pupil is presented. Computer simulation of this model demonstrates the role played by each of the elements in the pupil pathways. Simulations of the effects of drugs and a few common abnormalities in the system also help to illustrate the workings of the internal processes. Computer models of this type can be used as teaching aids or as tools for testing of hypotheses regarding the system.     

Self-monitoring processes and Holland Vocational Preferences among college students.

Examined the association between self-monitoring and occupational preferences. 237 undergraduates completed Snyder and Gangestad's (1986) revised self-monitoring scale and Holland's (1977) Vocational Preference Inventory (VPI). Regression analyses showed that men who valued congruence between their beliefs and behavior (i.e., low self-monitors) preferred social occupations. Men who were inclined to modify their behavior to fit social situations (i.e., high self-monitors) preferred enterprising occupations. In contrast, high self-monitoring women preferred artistic occupations. It is argued that these gender-neutral occupations permit high self-monitoring women to use their social skills but without the constraints found in male dominated enterprising occupations. Results support the assumption that people prefer occupations compatible with their social skills. Implications for career counseling and further research are noted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)