黑葵花籽皮黑色素提取及影响其稳定性因素分析

采用碱性溶液提取、酸水解沉淀等工艺分离纯化了黑葵花籽皮色素，呈天然黑色，其得率为12．5％（以粗品于原料为准），并对该色素的理化性质等进行了较系统的研究．结果表明：黑葵花籽皮黑色素耐光、耐热；对还原剂较稳定，对强氧化剂不够稳定；碱性条件下较稳定；Cu^2＋，Ca^2＋，Na^＋,Zn^2＋等金属离子对该色素有护色、增色作用，Fe^3＋，Al^3＋虽有减色作用，但不明显；是一种性能优良的天然黑色素。     

高中阶段学生资助政策分析

本文从个人能力、家庭社会经济背景和学费水平等方面分析了影响高中学生资助的主要因素,提出政府应该参照中等职业学校学生资助政策,建立全国性的普通高中学生资助体系,同时区分竞争性的"奖优"资助和非竞争性的"扶贫"资助.     

浅谈《数学实验》课程中实验题材的取材原则

《数学实验》课程是高校培养应用型人才,推进数学课程体系改革的标志性成果。在《数学实验》课程的教学过程中,选取恰当的实验题材是保证和提高教学质量的重要支柱和基础。本文真对《数学实验》课程中实验题材的取材原则进行了探讨。     

The impact of leadership and stakeholders on the success/failure of e-government service: Using the case study of e-stamping service in Hong Kong

Using e-stamping service in Hong Kong as a case study, this paper examines the impact of leadership and stakeholders on the success or failure of e-government service in Hong Kong. Multiple methods are used for data collection: documents and archival record research, direct observation, and interviews. Results show that both leadership and stakeholders have an impact on the success of e-stamping service.     

Who gets more financial aid in China? A multilevel analysis

The Chinese financial aid system intends to increase the affordability of postsecondary education and provide access to college for disadvantaged students. However, the research base for access to aid in China is extremely thin. Using data from a large cross-sectional survey in Beijing, this study found that attending selective institutions with high-ability peers was positively correlated with the amount of aid awarded and the probability of receiving aid. Female students, students with college-educated fathers, and students from poorer households were expected to receive more aid. Junior and senior students along with more able individuals in science-related majors obtained significantly more financial assistance.     

Optimal residual generation for fault detection in linear discrete time-varying systems with uncertain observations

This work deals with the problem of optimal residual generation for fault detection (FD) in linear discrete time-varying (LDTV) systems subject to uncertain observations. By introducing a generalized fault detection filter (FDF) with four parameter matrices as the residual generator, a novel FDF design scheme is formulated as two bi-objective optimization problems such that the sensitivity of residual to fault is enhanced and the robustness of residual to unknown input is simultaneously strengthened. A generalized operator based optimization approach is proposed to deduce solutions to the corresponding optimization problems in operator forms, where the related H_∞/H_∞ or $H_{?}/H_{\infty }$ FD performance index is maximized. With the aid of the addressed methods, the connections among the derived solutions are explicitly announced. The parameter matrices of the FDF are analytically derived via solving simple matrix equations recursively. It is revealed that our proposed results establish an operator-based framework of optimal residual generation for some kinds of linear discrete-time systems. Illustrative examples are given to show the applicability and effectiveness of the proposed methods.     

小楼一夜听春雨——解读陆游《临安春雨初霁》中的"无聊"

陆游的《临安春雨初霁》以其对文人日常生活细致生动的描写,成为宋诗中文人诗的名篇。但在诸本文学史称赏这首诗的闲情雅致之时。却忽略了其背后隐藏着陆游在特定时间与空间下形成的调怅“无聊”情绪,这首诗是英雄失路的另一种表达。     

人民币汇率变动对我国体育用品制造业出口贸易结构的影响——基于2006.1-2010.5月度数据的实证研究

以2006年1月至2010年5月的月度数据为分析样本,在系统考虑影响我国体育用品制造业出口贸易的各种宏观经济因素的基础上,通过运用时间序列的单位根检验、协整关系检验与误差修正模型等方法,对人民币汇率变动与我国体育用品制造业出口贸易结构的长短期冲击效应进行了实证研究。结果表明:从长期来看,在控制其他宏观经济影响因素的前提下,人民币升值对体育用品制造业总出口贸易、球类制造业出口贸易、体育器材及配件制造业出口贸易均产生了非常明显的抑制效应。就短期而言,人民币升值对体育用品制造业出口贸易结构也产生了强烈的负向冲击作用。根据所得结论,探讨了导致该现象的相关原因,并就人民币汇率变动对我国体育用品制造业发展的正负面影响展开讨论。最后,从政府层面、企业层面及金融工具层面出发,提出了基于人民币汇率变动的我国体育用品制造业发展的应对策略,以供相关部门决策参考。     

Inducing self-rotation of cells with natural and artificial melanin in a linearly polarized alternating current electric field

The phenomenon of self-rotation observed in naturally and artificially pigmented cells under an applied linearly polarized alternating current (non-rotating) electrical field has been investigated. The repeatable and controllable rotation speeds of the cells were quantified and their dependence on dielectrophoretic parameters such as frequency, voltage, and waveform was studied. Moreover, the rotation behavior of the pigmented cells with different melanin content was compared to quantify the correlation between self-rotation and the presence of melanin. Most importantly, macrophages, which did not originally rotate in the applied non-rotating electric field, began to exhibit self-rotation that was very similar to that of the pigmented cells, after ingesting foreign particles (e.g., synthetic melanin or latex beads). We envision the discovery presented in this paper will enable the development of a rapid, non-intrusive, and automated process to obtain the electrical conductivities and permittivities of cellular membrane and cytoplasm in the near future.