Modeling and Experimentation of Ultra-precision Grinding of Asphercial System

超精密磨削加工已广泛应用于轴对称非球面光学元件及硬脆材料的加工中,加工过程中砂轮的不平衡量和机床主轴引起的砂轮微小振动和摆动将直接影响工件表面质量。本文分析了加工过程中产生的微振动现象,建立磨削中振动引起工件表面轮廓误差的数学模型;设计一套微振动实验系统,建立系统动力学模型并进行实验研究。实验结果表明:优化选择砂轮转速、工件转速和加工进给速度,可有效减小砂轮振动,提高工件表面精度。Ultra-precision grinding is widely used in process on axis-symmetrical aspherical elements and hard-brittle material,the micro vibration and swing evoked by imbanlance of the grinding wheel and principal axis of the machine tools affect the surface quality of the elements directly.Micro vibration phenomena appeared in the processing was analyzed,a mathematic model about the error of elements' surface figure evoked by vibration was built,a experiment system of micro vibration was designed and a dynamics model of the system was built.The result of experiment shows that choosing a reasonable grinding parameter can effectively reduce vibration of the grinding wheel and improve the precision of elements' surface.国家“863”高科技资助项目(8638042416

Design and Implementation of Intelligent Home Control System Based on Android and Arduino

作为时下最炙手可热的移动应用端操作系统,Android以其显著的开放性、便于开发的灵活性、能够与Google应用的无缝对接性及丰富的第三方软硬件; 资源等成为智能应用系统不可或缺的组成部分;Arduino单片机系统以其开源的电子原型平台、灵活便捷的设计和丰富的传感器资源等被广泛应用。其与Ja; va和C语言相类似的基于; Wiring/Processing的语言开发环境更是受到越来越多的电子爱好者和开发者的青睐。本文以移动手机安卓系统为无线控制终端,结合Ardui; no单片机系统,设计并实验仿真了一款基于Android与Arduino的智能家居控制系统,以控制; LED灯示例,通过网络http传输控制指令到Arduino单片机系统,Arduino根据所接收到的指令,控制不同的家居电器完成所要求的工作任务。; 仿真实验表明,文章所设计方法行之有效,可以灵活的运用到日常家居电器设备,提供了一种智能家居系统设计的新思路,具有易实现,应用广的特点。As one of the most sought-after mobile application terminal operating; system, Android has become an indispensable part of the intelligent; application system, because it has the features of definite openness,; flexibility for development, perfect connection with Google applications; and abundant third party software and hardware resources and so on.; Arduino MCU system is widely used in society because of its; characteristics of open source electronic prototype platform, flexible; and convenient design, rich sensor resources, etc. Moreover, its classes; Java and C language based on Wiring/Processing development environment; are becoming more and more popular among the electronics enthusiasts and; developers. Taking the mobile phone Android system as wireless control; terminal, and combining Arduino MCU system, an intelligent home control; system based on Android and Arduino is designed and implemented in this; paper. By controlling LED lamp samples, with the network HTTP; transmission control instructions sending to the Arduino MCU system, and; according to the received instructions, Arduino can control different; household electrical appliances to complete the required tasks.; Experiments show that the methods designed in this paper can be flexibly; applied to daily household appliances, such as, home appliance control,; security equipment, etc. This paper provides a new idea for the design; of intelligent home system, which is easy to implement and widely used.2015年度"福建省高校杰出青年科研人才培育计划"项目; 2015年福建省高等学校创新创业教育改革项目;; 2016年本科高校重大教育教学改革研究项目; 2016年省级互联网实验教学示范中心项目; 2016年福建省高等学校服务产业特色专业建设项

一种基于Gabor描述的概率子空间人脸识别方法

该文提出了一种Gabor小波域的概率子空间人脸识别方法,简称GPSA方法。考虑到Gabor小波在人脸识别中的优势,首先给出了一种改进的人脸图像Gabor特征描述方法,在此基础上建立基于Gabor特征的概率子空间模型,人脸识别按照概率匹配方式进行,从而有机集成了Gabor特征描述和基于类内、类间变化的概率子空间分析两者所提供的鉴别信息,增强了人脸识别系统的鲁棒性。在包括190人的人脸数据库上的实验结果表明,所提出方法的识别性能较现有的概率子空间分析方法有了较明显的改善

求解大规模0-1背包问题的主动进化遗传算法

针对遗传算法求解大规模0-1背包问题中存在的不足,将定向变异机制引入到遗传算法中,提出了基于主动进化遗传算法的0-1背包问题求解算法。该算法利用概率编码方案对种子个体进行编码,每代种群中的个体通过对该代种子个体进行测度而产生,用于定向变异的诱变因子将参与种子个体的进化。实验结果表明,该算法具有较好的全局寻优能力和执行效率

Research on Image Recognition Basd on BP Neural Network

BP神经网络具有较强的容错性和自适应学习能力,因而在数字图像识别领域有着广泛的应用。本文在经典BP神经网络的基本算法的基础上,对BP算法的参数设置进行了优化,实现了一种基于分类的改进BP神经网络算法。通过探讨BP神经网络在数字图像分类识别中的应用,详细考察了各种参数对识别效果的影响。实验结果证明改进后的算法有很好的实用价值。Back-propagation neural network with high fault-tolerance and good adaptive learning ability,is found great applications in digital image recognition.This paper presents an improved algorithm through setting new parameters based on traditional BP algorithm,applies it to digital image recognition and analyzes the influence produced by improved parameters.The experimental result shows that the improved algorithm has a certain practical value.国家985二期信息创新平台项目(0000-X07204

Comparative Study on Characteristics of Urban Rainfall Runoff from Two Urban Lawn Catchments in Macau and Xiamen

在澳门与厦门分别选一分流制管道类型的绿地小流域开展降雨径流监测,以研究城市绿地降雨径流污染特征.结果表明,两城市绿地小流域降雨径流的主要污染物为COd、TP、nO3--n,其EMC平均值分别为165.77--60.48 Mg/l、0.96--0.44 Mg/l和7.16--1.18 Mg/l;两城市绿地的COd、TP、nO3--n污染负荷平均值分别为6.53--0.63 kg/HM2、0.037 5--0.004 7 kg/HM2和0.012 2--0.012 8 kg/HM2;绿地降雨径流污染物浓度峰值出现时间早于径流量峰值;城市绿地降雨径流初始冲刷效应不明显,厦门绿地小流域降雨径流COd、TSS、TP及nO3--n的ff30分别为36.26%、26.13%、28.13%和39.03%.基于多元回归分析结果表明,总降雨量和总径流量是影响绿地降雨径流污染初始冲刷效应的主要因素.A comparative study on characteristics of stormwater runoff from two urban lawn catchments in Macau(ELH) and Xiamen(PGH) with separated sewer system were conducted.The result obtained shows that COD,TP and(NO---_3-N) are the major pollutants with mean EMC of 165.77-60.48(mg/L),0.96-0.44(mg/L) and 7.16-1.18(mg/L),respectively,and the mean values of pollutants loads of COD,TP and(NO---_3-N) from study lawn catchments are 6.53-0.63(kg/hm--2),(0.037?5)-(0.004?7)(kg/hm--2) and(0.012?2)-(0.012?8)(kg/hm--2),respectively.Peak values of major pollutant concentrations usually precede the flow peak.First flush effect of rainfall runoff from two study catchments is no obvious,which can be reflected by the low mean value of FF_(30) of TSS,COD,TP and(NO---_3-N),with 36.26%,26.13%,28.13% and 39.03%,respectively.Based on multivariate statistical analysis,first flush effect from urban lawn rainfall runoff is greatly influenced by total rainfall amount(T_r) and total runoff volume(V).国家自然科学基金项目(50778098);福建省青年人才项目(2007F3093

The Phylogeny Tree Reconstruction Based on the Usage Frequencyof Codons and Corresponding Complementary Codons

为了更深入地了解密码子与互补密码子使用相关的内涵,70个单细胞和多细胞生物被更进一步的分析。结果得到70种细胞生物具有较高的相关系数平均值(0.5101,标准差是0.1389),表明密码子与其互补密码子使用间确实存在正的使用相关联系,进一步地支持了以前的结果。此外,通过对70个单细胞和多细胞生物在基于密码子与互补密码子使用频率差异,以及配对频率的高低信息的分析基础上,绘制进化树,得到的进化树与传统的进化树非常接近。The hypothesis that a codon bias usage is identical to its complementary codon usage preference has been investigated by using the relationship analysis of codons vs their complementary ones among 70 organisms. Significantly positive usage correlations between codons and their complementary ones were found and its implication in biology was also analyzed. The codoncomplementary codon tree was further built, which fairly exhibited the evolutionary relationship of these organisms. The results not only demonstrated the validity of our hypothesis,but also manifested the usefulness of correlation analysis in studying on codon usage pattern and molecular evolutionary mechanisms of organism.ThisworkwassupportedbyagrantfromtheNationalNaturalScienceFoundationofChina(No.60305001)andagrantfromtheScienceandTechnologyMinistryofChina(PreliminaryStudyonFunctionalGenomeSystematics)(No.2001CCA01400)

CO concentration and temperature measurements in a shock tube for Martian mixtures by coupling OES and TDLAS

CO concentration and gas temperature distribution are diagnosed behind a strong shock wave simulating the Martian atmosphere entry processes by coupling optical emission spectroscopy (OES) and tunable diode laser absorption spectroscopy (TDLAS). The strong shock wave (6.31 +/- A 0.11 km/s) is established in a shock tube driven by combustion of hydrogen and oxygen. Temperature of the shock-heated gas is inferred through a precise analysis of the high temporal and spatial resolution experimental spectral of CN violet system (B (2) I pound (+) -> X (2) I pound (+), Delta v = 0 sequence) using OES. A CO absorption line near 2,335.778 nm is utilized for detecting the CO concentration using scanned-wavelength direct absorption mode with 50 kHz repetition rate. Combined with temperature results from OES, CO concentration in the thermal equilibrium region is derived. The current experimental results are complementary for determining an accurate rate coefficient of CO2 dissociation and validation relevant chemical kinetics models in Mars atmosphere entry processes

中国物理海洋学研究70年：发展历程、学术成就概览

本文概略评述新中国成立70年来物理海洋学各分支研究领域的发展历程和若干学术成就。中国物理海洋学研究起步于海浪、潮汐、近海环流与水团,以及以风暴潮为主的海洋气象灾害的研究。随着国力的增强,研究领域不断拓展,涌现了大量具有广泛影响力的研究成果,其中包括:提出了被国际广泛采用的"普遍风浪谱"和"涌浪谱",发展了第三代海浪数值模式;提出了"准调和分析方法"和"潮汐潮流永久预报"等潮汐潮流的分析和预报方法;发现并命名了"棉兰老潜流",揭示了东海黑潮的多核结构及其多尺度变异机理等,系统描述了太平洋西边界流系;提出了印度尼西亚贯穿流的南海分支(或称南海贯穿流);不断完善了中国近海陆架环流系统,在南海环流、黑潮及其分支、台湾暖流、闽浙沿岸流、黄海冷水团环流、黄海暖流、渤海环流,以及陆架波方面均取得了深刻的认识;从大气桥和海洋桥两个方面对太平洋–印度洋–大西洋洋际相互作用进行了系统的总结;发展了浅海水团的研究方法,基本摸清了中国近海水团的分布和消长特征与机制,在大洋和极地水团分布及运动研究方面也做出了重要贡献;阐明了南海中尺度涡的宏观特征和生成机制,揭示了中尺度涡的三维结构,定量评估了其全球物质与能量输运能力;基本摸清了中国近海海洋锋的空间分布和季节变化特征,提出了地形、正压不稳定和斜压不稳定等锋面动力学机制;构建了"南海内波潜标观测网",实现了对内波生成–演变–消亡全过程机理的系统认识;发展了湍流的剪切不稳定理论,提出了海流"边缘不稳定"的概念,开发了海洋湍流模式,提出了湍流混合参数化的新方法等;在海洋内部混合机制和能量来源方面取得了新的认识,并阐述了混合对海洋深层环流、营养物质输运等过程的影响;研发了全球浪–潮–流耦合模式,推出一系列海洋与气候模式;发展了可同化主要海洋观测数据的海洋数据同化系统和用于ENSO预报的耦合同化系统;建立了达到国际水准的非地转(水槽/水池)和地转(旋转平台)物理模型实验平台;发展了ENSO预报的误差分析方法,建立了海洋和气候系统年代际变化的理论体系,揭示了中深层海洋对全球气候变化的响应;初步建成了中国近海海洋观测网;持续开展南北极调查研究;建立了台风、风暴潮、巨浪和海啸的业务化预报系统,为中国气象减灾提供保障;突破了国外的海洋技术封锁,研发了万米水深的深水水听器和海洋光学特性系列测量仪器;建立了溢油、危险化学品漂移扩散等预测模型,为伴随海洋资源开发所带来的风险事故的应急处理和预警预报提供科学支撑。文中引用的大量学术成果文献(每位第一作者优选不超过3篇)显示,经过70年的发展,中国物理海洋学研究培养了一支实力雄厚的科研队伍,这是最宝贵的成果。这支队伍必将成为中国物理海洋学研究攀登新高峰的主力军