中国平均最高气温突变分析

基于1956—2005年中国逐日最高气温的气象站点数据,采用Mann—Kendall法、滑动t检验和Yamamoto法三种方法对其进行突变检验,结果发现：全国8大自然地理区的年和四季平均最高气温的突变基本上发生在20世纪90年代．在区域上,表现出北早南晚的空间差异;在四季中,冬季发生突变的时间最早,秋季各地发生突变均不明显,春夏两季和年平均最高气温发生突变较晚且时间类似．通过与日平均气温的突变时间比较发现,平均最高气温突变的出现时间均晚于日平均气温的突变．     

山东省1960—2009年气温变化特征分析

笔者利用多种方法对山东省1960—2009年的年平均气温、季节平均气温进行了特征分析以及突变检验．分析结果表明：近50年来,山东省年平均气温呈现波动上升趋势,增温速率为0．27℃／10a,并在1997年发生增温突变．增暖趋势的显著性为：冬季〉春季〉秋季〉夏季．春季平均气温增温速率为0．35℃／10a;夏季增温缓慢,以0．08℃／10a的速率增加;秋季增温略低于春季,增温速率为0．23℃／10a;冬季增温趋势最为明显,为0．45℃／10a．季节突变分析表明：春季平均气温在2000年发生突变,秋季均温在2004年发生突变,冬季均温在1986年发生突变．     

基于555定时器的声光双控照明灯设计

本文提出一种基于555定时器的声光双控照明电路设计,该设计廉价可靠,可广泛应用于普通场所。     

An experimental investigation of tribological performance of triangular textures in water lubrication regime

Surface texturing has been considered as an effective approach to improve the tribological performances.Based on the consideration of enhancing the tribological performance,the experiments are carried out to investigate tribological performance of triangular textures in water lubrication.The textures are generated by the Nd:YAG laser marking system,with an area density of 20%and a depth of 7 m and are distributed uniformly on the surface of the SiC rings.Compared with the circular textures,the triangular textures have obvious tribological anisotropy.The triangular textures in clockwise direction show the best friction reduction effect among the three textures.The friction reduction mechanisms of the triangular textures in clockwise direction are also analyzed and discussed.     

一类退化椭圆方程在高阶特征值处近共振的多重解

通过对一类退化椭圆方程的研究,利用临界点理论中的极小极大原理和一个广义的Landesman-Lazer类型条件,获得了退化椭圆方程在高阶特征值处近共振的多重解。     

哲学研究中的"语言转向"及其意义

本文在对西方哲学中关于语言问题研究的轨迹进行简要梳理的基础上，集中探讨了现代西方哲学语言转向的核心问题、主要观点及其所呈现的两条基本脉络——“逻辑建构”和“人文阐释”。进而，对这种转向所形成的语言世界建构之于哲学研究的价值和意义，给予了剖析和阐发。哲学研究的语言转向昭示人们，人类语言永远是人类世界的弥久而常新的问题。     

Effects of carbon sources and carbon contents on the electrochemical properties of LiFePO4/C cathode material

LiFePO₄/C composites are prepared by using two types of carbon source: one using polymer (PAALi) and the other using sucrose. The physical characteristics of LiFePO₄/C composites are investigated by X-ray diffraction), scanning electron microscopy, BET, laser particle analyzer, and Raman spectroscopy. Their electrochemical properties are characterized by cyclic voltammograms, constant current charge–discharge, and electrochemical impedance spectra. These analyses indicate that the carbon source and carbon content have a great effect on the physical and electrochemical performances of LiFePO₄/C composites. An ideal carbon source and appropriate carbon content can effectively increase the lithium-ion diffusion coefficient and exchange current density, decrease the charge transfer resistance (R _ct), and enhance the electrochemical performances of LiFePO₄/C composite. The results show that PAALi is a better carbon source for the synthesis of LiFePO₄/C composites. When the carbon content is 4.11 wt.% (the molar ratio of PAALi/Li₂C₂O₄ was 2:1), as-prepared LiFePO₄/C composite shows the best combination between electrochemical performances and tap density.     

Capture efficiency of Escherichia coli in fimbriae-mediated immunoimmobilization

Capturing pathogens on a sensor surface is one of the most important steps in the design of a biosensor. The efficiency of a biosensor at capturing pathogens has direct bearing on its sensitivity. In this work we investigated the capturing of Escherichia coli on substrates modified with antibodies targeting different types of fimbriae: K88ab (F4), K88ac (F4), K99 (F5), 987P (F6), F41, and CFA/I. The results suggest that all these fimbriae can be used for the efficient immobilization of living E. coli cells. The immobilization efficiency was affected by the purity and clone type of the antibody and the fimbriae expression level of the bacteria. For a specific fimbriae type, a higher immobilization efficiency was often observed with the monoclonal antibodies. Immunoimmobilization was utilized in an antibody microarray immersed in a mixed culture of pathogens to demonstrate the rapid and simultaneous label-free detection of multiple pathogens within less than 1 h using a single test. The capture rate of living pathogens exceeds a single bacterium per 100 × 100 μm(2) area per 0.5 h of incubation for a bulk concentration of 10(5) cfu/mL.     

Mechanical behavior of a pH-sensitive hydrogel ring used in a micro-optical device

A hydrogel is a polymer network that can absorb a large quantity of solvent and swell due to a physical or chemical stimulus. Hydrogels are more and more used as smart materials in recent micro-applications. This fact requires the development of adequate models and simulation tools for their large deformation behavior. These models must also predict the onset of instabilities, such as folding or creasing. In this work, we study an interesting application of adaptive optical microsystem using a previously developed theory of inhomogeneous large deformation of a pH-sensitive hydrogel. The devices function is based on the swelling of a ring made of a pH-sensitive hydrogel. The latter controls the focal length of the liquid microlens. Our aim is to analyze major design parameters that affect the hydrogel ring behavior and the function of the micro-optical device. The problem is solved numerically with the finite element commercial software ABAQUS. Various modes of large deformation and the influence of the rings aspect ratio on the behavior of the micro-device are investigated. Results show that, for relatively short rings, a stable swelling takes place. Rings with a relatively big aspect ratio can have an unstable swelling with the propagation of a creasing instability. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Resonant behavior of a membrane of a dielectric elastomer

This paper analyzes a membrane of a dielectric elastomer, prestretched and mounted on a rigid circular ring, and then inflated by a combination of pressure and voltage. Equations of motion are derived from a nonlinear field theory, and used to analyze several experimental conditions. When the pressure and voltage are static, the membrane may attain a state of equilibrium, around which the membrane can oscillate. The natural frequencies can be tuned by varying the prestretch, pressure, or voltage. A sinusoidal pressure or voltage may excite superharmonic, harmonic, and subharmonic resonance. Several modes of oscillation predicted by the model have not been reported experimentally, possibly because these modes have small deflections, despite large stretches.