基于ATMEGA48V超低功能便携式紫外强度仪

近年来,紫外线对人类的生活和环境的影响在全世界受到了普遍关注.要利用好紫外线,需及时方便地得知紫外线的强度.本设计利用ATMEL公司出品的ATMEGA48V作为主处理器,配合美国PerkinElmer公司的紫外线传感器UV10SF,紫外线强度用段式液晶进行显示,并重点针对便携的要求,严格选择元件和电路,研制出了超低功耗、小体积的紫外线强度仪,有很强的实用性和应用前景.该文详细阐述了本设计的硬件电路设计分析和软件程序设计分析.     

便携式日光紫外线指数检测仪设计

设计并制作了一种便携式、低成本的日光紫外线指数检测仪.选择了CdS光敏电阻作为光电探测器件,通过合理的光谱剪裁,保留了300～400 nm波段的光,设计了简单的比较器电路,通过LED的明灭可直观显示紫外线的强度等级.实际测量的结果表明:仪器对日光中紫外线指数的测量是准确可靠的.     

高灵敏度绝缘子电晕放电检测系统研究

绝缘子是电力系统中非常重要的一类电气设备,由于电、热、机械力、污秽的积累等环境因素的作用会使其绝缘性能出现劣化和下降,可能使得绝缘子的表面形成放电,甚至会发生沿面闪络,危害了电力系统的安全;在此基础上提出基于日盲紫外线精确测试紫外线强度的方法,研制了基于日盲紫外线检测技术的绝缘子电晕放电检测装置,通过不同劣化程度和不同污秽条件的盘行悬式瓷绝缘子的实际测试,验证了该装置通过日盲紫外线强度的监测能够定性判断绝缘子的劣化程度和污秽程度,为输电线路绝缘子实时状态监测提供依据.     

一种全屏幕动画技术的C语言编程技巧

就一些特殊要求下,需要实现图形“畸变”动画效果的编程方法进行了论述,提出了汇编语言功能的调用方法.特别介绍了一种模拟屏幕宽度“连续”变化的编程技巧.同时,给出了一种编程实例.     

计算机编程方式改进的必要性及优化策略探讨

第三次工业革命的全面展开,使科技和信息成为21世纪的主题,信息技术的重要性不言而喻,它让人相识、相知,使人类的生活发生了翻天覆地的变化.计算机编程是相关计算机人员通过计算机语言对程序进行编写、输入,然后计算机执行程序的过程.因此,计算机编程是电脑技术中的重要板块,地位十分重要.在一定程度上,计算机编程决定了计算机的运行.分析了计算机编程方式改进的必要性,探讨了计算机编程方式的现状及计算机编程方式的优化策略.     

暴雨强度公式参数提取的Matlab实现

针对暴雨强度公式中参数如何确定的问题,根据不同历时和重现期的暴雨强度资料,引入基于非线性最小二乘法原理的数学优化技术.首先利用Matlab中自带的软件编程求出的结果作为初始值,然后采用Excel规划求解得到最佳参数.实例计算结果表明,该算法确定的暴雨强度公式精度能满足国家规范要求,有效解决实际优化设计问题.     

RF—510智能编程器的适用范围

上期本刊载文简单介绍了RF-510智能编程器的强大功能,这编文章则主要介绍它的适用范围。 RF-510智能编程器可以编程和写入众多厂家的近千种器件,因此可以说它是一种万能写入器。可以用RF-510智能编程器编程和写入的集成电路芯片有以下五大类;·单片机芯片MCU(或称MPU);·可紫外线擦除的存储器EPROM;·并行电可擦电可写存储器EEPROM;     

Suvil紫外线测量仪

夏天的时候我们无法躲避阳光的暴晒，除非你不辞辛苦地早出晚归，披星戴月。特别是在去海边度假的时候，有的时候我们即使涂抹了防晒霜，但还是难逃被晒伤的噩运。根本原因就是我们不清楚当前的紫外线照射强度。这款Suvil的紫外线测量仪可以清楚地显示出当前的紫外线强度如果照射达到一定的指标，它就会报警提示你尽量回避当前的日晒。     

用户宏程序在圆台数控加工中的应用

在数控加工中,常常会遇到数量少、品种繁多、有规则几何形状的工件,加工时就会出现重复多次的相同或者以一定规律变化的运动轨迹,编程人员经常使用子程序或用户宏程序对其编程进行简化.使用用户宏程序,设计适当的变量来表示加工轨迹规律性的变化,不仅可以节省大量的编程时间,而且使用起来方便快捷,甚至可以实现简单三坐标立体型面的手工编程,因而可提高数控加工的性能.     

超临界CO2流体中空化泡动力学过程分析

考察各参数影响超临界CO2流体中超声空化动力学过程的规律.应用非线性Rayleigh-Plesset方程模拟空化泡运动过程,利用Matlab软件编程求数值解,结果:空化泡初始半径或超声波频率增大,空化变易,强度变弱;超声波的声压幅值增大.空化变易,强度变强;超临界CO2流体的压力的增大,空化变难,强度变弱;温度不会影响空化的难易程度,只是随着温度升高,强度变强.     

Spectral indices for lithologic discrimination and mapping by using the ASTER SWIR bands

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a research facility instrument launched on NASA's Terra spacecraft in December 1999. Spectral indices, a kind of orthogonal transformation in the five-dimensional space formed by the five ASTER short-wave-infrared (SWIR) bands, were proposed for discrimination and mapping of surface rock types. These include Alunite Index, Kaolinite Index, Calcite Index, and Montmorillonite Index, and can be calculated by linear combination of reflectance values of the five SWIR bands. The transform coefficients were determined so as to direct transform axes to the average spectral pattern of the typical minerals. The spectral indices were applied to the simulated ASTER dataset of Cuprite, Nevada, USA after converting its digital numbers to surface reflectance. The resultant spectral index images were useful for lithologic mapping and were easy to interpret geologically. An advantage of this method is that we can use the pre-determined transform coefficients, as long as image data are converted to surface reflectance.     

面向内存云的数据块索引方法

内存云(RAMCloud)通常通过移动数据的位置来解决内存利用率低的问题,致使Hash表数据定位失效,查询数据效率低下;另一方面,在数据恢复过程中由于不能快速定位到需要的数据,每台备份服务器返回的数据段不能更好地组织起来。针对以上问题,提出内存云全局键(RGK)及二叉树索引。RGK分为三部分:定位到主服务器、定位到段以及定位到数据块。前两部分构成协调器索引键(CIK),在恢复中借助构造的协调器索引树(CIT)能够定位到段所在的主服务器;后两部分构成主服务器索引键(MIK),数据在内存中位移后也能通过主服务器索引树(MIT)快速获取到数据。与传统内存云集群相比,主服务器获取数据块的时间随数据吞吐量的增大而明显减少;协调器在闲散时间、重组日志时间等方面均有下降。实验结果表明,全局键在构造的二叉索引树的支持下能有效缩短获取数据及快速恢复的时间。     

Quantile autoregression neural network model with applications to evaluating value at risk

We develop a new quantile autoregression neural network (QARNN) model based on an artificial neural network architecture. The proposed QARNN model is flexible and can be used to explore potential nonlinear relationships among quantiles in time series data. By optimizing an approximate error function and standard gradient based optimization algorithms, QARNN outputs conditional quantile functions recursively. The utility of our new model is illustrated by Monte Carlo simulation studies and empirical analyses of three real stock indices from the Hong Kong Hang Seng Index (HSI), the US S&P500 Index (S&P500) and the Financial Times Stock Exchange 100 Index (FTSE100).     

Comparing measures of urban land use mix

We review a variety of common measures of urban land use mix in order to understand their differences and to identify their strengths and limitations. We then apply these measures to data from a Monte Carlo simulation to ascertain statistical relationships among them, finding that they can be placed into four groups where measures within each group produce highly consistent results: Percentage and Exposure Index; all varieties of the Atkinson Index; Balance, Entropy, and Herfindahl–Hirschman indices; and the Dissimilarity and Gini indices. We find that when analyzing two dimensions of land use, generally both the Balance Index and the Dissimilarity Index should be used, and that the Dissimilarity Index should be tested at multiple scales. We provide a number of other practical recommendations about which mixed use measure to apply given the contextual information available to a researcher or analyst.     

A self-converging atomized mist spray device using surface acoustic wave

This paper presents an innovative versatile method aiming at rapid fabrication of a master for polydimethylsiloxane (PDMS) molding. This technology is relying on liquid dielectrophoresis electromechanical microfluidic transduction for programmable ultraviolet (UV) glue manipulation. It enables formation of the master in a tailor-made approach, avoiding the need of micromachined structures unlike in conventional methods. The principle is simple: UV glue, while in liquid phase, is actuated onto an array of electrodes patterned on a Si substrate and cured afterward by UV exposure. The silicon chip and the glue microstructures defined atop of it then play the role of a master for PDMS molding. The glue microstructures’ shape is hemispherical which is of high interest for many microfluidic applications. This concept is assessed and validated with two different PDMS chip replica designs, both of them illustrating representative applications in continuous microfluidic: a T-junction design for inflow droplet generation and a “Quake” type valve. Lastly, this protocol has shown to be recyclable since the UV glue microstructures once formed can be easily removed by immersion in an acetone bath, such as the chip is reset and can be reprogrammed afterward to build another glue channels geometry.     

Estimations of Chlorophyll Content from Vegetation Indicesby Using PROSPECT and DART

With the aid of a well known leaf optical model PROSPECT and a canopy scale model DART (Discrete Anisotropic Radiative Transfer),sensitivities between chlorophyll content and six different vegetation indices were investigated by simulating eucalyptus,one of a dominant fast growing tree in China,as an example.Vegetation indices used here include Normalized Difference Vegetation Index (NDVI),Structure Insensitive Pigment Index (SIPI),Colouration Index (COI),Simple Ratio Index (SR),Cater Index (CAI),and Red edge Position Linear Interpolation (REP_Li).Results indicate that at the leaf scale,COI and SIPI are sensitive to the LCC (Leaf Chlorophyll Content)as the Chlorophyll Content changes.Meanwhile,no obvious saturation phenomenon is observed for these two indices compared to other indices.Further investigations show that all these vegetation indices are incapable of estimating LCC at the canopy scale,due to significant influences from LAI(Leaf Area Index).Nevertheless,it suggests that SIPI and COI can be applied to estimate the CCC (Canopy Chlorophyll Content).     

Fast‐response study of polymer‐stabilized VA‐LCD

Abstract— Polymer stabilization is introduced in VA‐type LCDs, and fast response time can be achieved along with a high contrast ratio.¹ A small amount of reactive monomer is mixed with liquid crystal and forms a polymer layer above the alignment layer by using a UV process. The pre‐tilt angle of the liquid crystal is stabilized, and a faster response time can be realized when the bias pre‐tilt angle from 90° is increased. The properties of reactive monomers and liquid crystal and the conditions of the UV process were studied. Based on the application of the proper monomer and LC, and an optima UV process, a 65‐in. 240‐Hz full‐HD TFT‐LCD, with a faster response time and high contrast ratio, has been developed.     

生态环境状况指数模型在全国生态环境质量评价中的应用

生态环境质量与人类的生存质量密切相关,生态环境质量评价为生态环境质量的治理、改善提供重要参考。本文以全国土地利用遥感监测数据及MODIS的NDVI数据为基础,根据国家环保总局发布的生态环境评价规范,通过GIS空间分析功能提取生物丰度指数、植被覆盖指数、水网密度指数、土地退化指数和环境质量指数等5个指标,利用综合指数法计算全国范围的生态环境质量指数,对2005年全国范围进行生态环境评价,将全国生态环境质量分为5级。结果表明,2005年全国生态状况整体一般,西部较差,东部较好,有呈阶梯分布的趋势。     

Modelling and controller design for distributed parameter systems via residence time distribution

For chemical reactors with non-linear fluid dynamics, a linear model realisation is proposed. The inputs are the ingoing concentration of a certain component in the fluid, and the reaction rate. The output is the outgoing concentration. The realisation makes use of a first-order reaction equation, and the residence time distribution of the fluid particles inside the reactor. Also dead time is incorporated in the modelling. The method is tested on two non-linear models for which the residence time distributions are known analytically. The first model is a series of mixed tanks, and it is shown by simulation that the method gives an accurate approximation of the original model. The second model is a UV disinfection reactor, which has a dead time. For this model, the residence time distribution is first fitted by a form that is suitable for our realisation method. Simulations show that for realistic disturbances a high-performance linear controller can be designed. After that, the residence time distribution of a real life UV reactor (for which we have no model) is fitted by a suitable form. The fit is of the same quality as for the UV reactor model. This indicates that also for the real life UV reactor a high-performance controller can be designed.     

基于全文文档检索技术的化学教学模式

为了利用网络资源进行化学教学,提出了使用全文文档检索技术整合网络资源进行教学的模式。该技术由3部分组成：一是文档系统,各种格式的文档以文件的形式在服务器硬盘上使用文件系统进行组织。二是全文检索系统,使用Index Server对文档进行过滤和索引。三是检索系统,以IIS（Internet Information Server）为Web服务器,利用ADO访问Index Server数据库,使用ASP编程,实现检索和排序。实践证明该模式实现容易,操作简单,性能优秀,适合于大学化学教学。