Experimental studies on phase equilibria of PEG-water-dextran/ammonium sulfate systems and partitioning of albumin into two water-continuous phases

The clouding points and equilibrium concentrations of PEG/dextran/water and PEG /ammonium sulfate/water systems were experimentally determined for different molecular weights of PEG by titration method and direct determination of concentrations. In phase diagrams of PEG-water with ammonium sulfate or dextran, the addition of salt or dextran induced the phase separation of PEG-rich phases near the PEG-lean phases having the different partitioning of PEG. The concentrations of PEG in PEG-rich phases increase as the amounts of PEG or salt and dextran increase, while the concentrations of PEG in aqueous media decrease in any cases. The higher the molecular weight of PEG has, the wider the two-phase regions are. In dextran DT10 systems, the partition coefficients of egg albumin into PEG-lean phases increase with concentrations of dextran and the molecular weight of PEG. In ammonium sulfate systems, the partitioning coefficients showed a maximum, having lower partitioning at the very high and low concentration of salts. It is also observed that as the amounts of albumin increase, the partitioning of albumin into PEG-lean phase increases.     

Face detection based on skin color likelihood

We propose a face detection method based on skin color likelihood via a boosting algorithm which emphasizes skin color information while deemphasizing non-skin color information. A stochastic model is adapted to compute the similarity between a color region and the skin color. Both Haar-like features and Local Binary Pattern (LBP) features are utilized to build a cascaded classifier. The boosted classifier is implemented based on skin color emphasis to localize the face region from a color image. Based on our experiments, the proposed method shows good tolerance to face pose variation and complex background with significant improvements over classical boosting-based classifiers in terms of total error rate performance.     

Power management unit chip design for automobile active-matrix organic light-emitting diode display module

A power management unit (PMU) chip supplying dual panel supply voltage, which has a low electro-magnetic interference (EMI) characteristic and is favorable for miniaturization, is designed. A two-phase charge pump circuit using external pumping capacitor increases its pumping current and works out the charge-loss problem by using bulk-potential biasing circuit. A low-power start-up circuit is also proposed to reduce the power consumption of the band-gap reference voltage generator. And the ring oscillator used in the ELVSS power circuit is designed with logic devices by supplying the logic power supply to reduce the layout area. The PMU chip is designed with MagnaChip’s 0.25 μm high-voltage process. The driving currents of ELVDD and ELVSS are more than 50 mA when a SPICE simulation is done.     

用工农业废料配制的两种堆肥培育观赏植物

由工农业废料配制的两种堆肥作为试验用的基质:C1——酿造啤酒等废料(酵母和麦芽)加修剪下的柠檬树枝;C2——橄榄研磨厂废水的固体级分加橄榄树叶。以每种堆肥与泥炭藓泥炭或商品基质(CS)按不同的比例混合,可配制成16种基质。尽管基质的物理和理化特性例如总孔隙度和电导率(EC)都是合适的,但由堆肥提供的养分(氮和钾)释放缓慢,对金盏花发育的影响尤为明显。另一方面,由于对盐分含量敏感,EC和氯化物浓度是影响蒲包草生长的主要因素。为供金盏花发育的适宜的基质可以通过含量高达75?与泥炭或高达50?与CS混合,以及高达50?与泥炭或CS混合使用。对蒲包花来说,基质中堆肥比例应较低,可用50?与泥炭或CS混合,也可以用25?与泥炭或CS混合使用。因此,只要基质至少含有25%的泥炭或CS,源于工农业废料的堆肥可作为培育观赏植物的泥炭和CS的替代品。     

生物本体的研究与应用概况

生物本体是生物领域的科学知识与人工智能领域的本体方法有机结合的产物,用来建立生物科研领域的知识结构和概念模型。生物本体的研究对生物领域内部及相邻领域间的交流与合作具有重要推动作用。本文在简要介绍本体概念的基础上,阐述了生物本体的基本特点与研究意义,并分析了国内外多种生物本体的发展、研究与应用现状。     

基于ZigBee协议的无线传感网路及应用

无线传感网络因其巨大的应用前景,已经引起了学术界的高度关注,成为科学界研究的热点问题之一。本文先对无线传感网路进行基本概述,接着介绍了ZigBee协议,最后以家用自动化的实例描述了基于ZigBee协议的无线传感网路及应用。     

一种新的P2P系统中基于双ratings的声誉管理机制

声誉系统的效率取决于回馈的质量,现有P2P系统中的声誉模型不能处理合谋、不递交ratings等攻击,并且对无过失节点还存在不公平性,针对这些问题,提出了一个新的基于双ratings的声誉管理机制,采用两个度量来评价节点:服务信任和回馈信任,服务信任反映server提供服务的可靠性;回馈信任反映consumer汇报ratings的可信度.一次交易后,要求服务双方都递交ratings,依据这两个ratings对server的服务信任和consumer的回馈信任进行更新,并且server的服务信任更新与consumer的回馈信任紧密相关.为了防止恶意节点反复实施恶意行为或不递交rating,还提出了一个惩罚机制,作为对声誉模型的补充,仿真表明,提出的声誉管理机制能够抵制上述恶意攻击,减少不公平性.     

基于Django快速开发Web应用

Django是Python的一个优秀的开源Web开发框架,在Web开发方面具有简洁、清晰、高效、安全的优点,特别适合快速构建各类Web应用。通过一个留言板的开发实例,论述了基于Django快速开发Web应用的基本原理和过程。     

Effect of growth interruption time on the quality of InAs/GaSb type-II superlattice grown by molecular beam epitaxy

We systematically investigate the influence of growth interruption time on the properties of InAs/GaSb type-II superlattices (T2SLs) epitaxial materials grown by molecular beam epitaxy (MBE). X-ray diffraction (XRD) and atomic force microscope (AFM) are used to characterize the material quality and morphology. The full width at half maximum (FWHM) of the XRD 0th satellite peaks ranges from 32'' to 41'', and the root mean square (RMS) roughness on a 5 μm×5 μm scan area is 0.2 nm. Photoluminescence (PL) test is used to reveal the influence of the growth interruption time on the optical property. Grazing incidence X-ray reflectivity (GIXRR) measurements are performed to analyze the roughness of the interface. The interface roughness (0.24 nm) is optimal when the interruption time is 0.5 s. The crystal quality of T2SLs can be optimized with appropriate interruption time by MBE, which is a guide for the material epitaxy of high performance T2SL infrared detector.