Measuring the errors of form of industrial surfaces: prediction and optimization

To acquire maximum information on the geometrical errors of industrially made surfaces at a minimum cost, a method for estimating conditional probabilities of a random signal (Bayesian prediction) is applied to three-dimensional metrology. First, a surface is interpolated between data acquired on a coordinate measuring machine (CMM). Then, for a given probability, limit surfaces are computed that bind a region of space containing the known data and the most probable interpolation of the missing data of the surface. These bounds can be treated as the surface; their points can be considered as if they were actual CMM data when fitting a tolerance zone or a datum feature to the data. For Bayesian prediction, the basic hypotheses on the signal are stationarity, ergodicity, and gaussian density. Deviations from these hypotheses and their consequences on the prediction are taken into account and corrections are proposed.     

测定陶瓷材料阻力曲线的包络线法的改进

本文通过对压痕弯曲梁的压痕载荷和断裂强度关系的理论分析和推导,介绍了一种确定切点(即K曲线和R曲线的交点)的方法,这些切点的轨迹组成了R曲线,并通过实验对这种方法进行了验证。结果发现这种改进的包络线法与常规的包络线法所测得的阻力曲线相吻合。这种方法完善了常规的K曲线切点包络线法,更为重要的是它揭示了压痕弯曲梁的压痕载荷和断裂强度关系的物理内涵。     

基于EIGamal签名的隐私保护网上交易方案

针对网上交易时的用户个人隐私安全问题,依据不经意传输理论,基于ElGamal签名的不经意签名电子信封(OSBE)模型,提出了一个可保护用户隐私的网上交易数字商品方案.首先用户匿名付费给银行,然后银行将用户订购商品的数字签名发送给用户,接着用户使用数字签名与商家进行不经意信息交互,最后用户得到且只能得到自己订购的数字商品,商家并不知道用户订购何种数字商品.正确性证明和安全性分析结果表明,可以有效地保护用户在网上交易过程中的个人隐私,同时防止商家恶意欺诈行为.该方案签名相对较短,计算量较小,密钥动态变化,安全性更强.     

Large deformation and ultimate properties of biopolymer gels: 2. Mixed gel systems

Biphasic, mixed gels of agarose and gelatin were prepared, and their mechanical behaviour in tensile tests was determined, up to failure, utilising four decades of (constant) strain rate. The behaviour of pure agarose and pure gelatin in such tests has been determined previously. Suitable ‘blending-laws’ relating the small deformation shear modulus of the composite to the moduli of the component phases have also been discussed elsewhere. This report extends the latter treatment to the more aggressive large deformation regime, deriving bounds for modulus and break stress which closely model observed behaviour.     

气体压强对非晶InGaAs薄膜光学常数的影响

论述一种用透射谱包络线法计算非晶薄膜的折射率、消光系数和光学带隙的方法。通过正交实验确定除压强之外的工艺参数,研究压强的改变对薄膜主要光学常数的影响,运用最小二乘法、内插值法在matlab编程基础上,拟合出光学常数曲线,借由观察曲线的特点,分析在低工作气压下,气压的改变对光学常数的影响。     

辽宁地区农村住宅的节能研究

针对我国辽宁地区现有农宅普遍存在的采暖能耗高而居住热环境差的问题,通过对农村住宅的体型系数、平面节能设计、围护结构等方面进行充分分析,提出适合辽宁农村住宅的保温节能措施,从而增强农宅保温隔热能力,提高室内热舒适度。力求使辽宁农村住宅在经济、技术和节能方面均达到新农村建设的要求。     

测量超短激光脉冲啁啾阶数及量值的一种新方法

提出了一种测量超短激光脉冲啁啾阶数及量值的新方法。根据二次干涉自相关(IAC)包络比值对啁啾有很高灵敏度的特性,通过对IAC包络比值进行分析计算获得判断啁啾阶数的方法,并得到包络比值中央半宽与啁啾量值间的对应关系。采用IAC二次谐波检测系统对加浓染料激光器输出的脉冲进行测量,结果表明,被测超短激光脉冲含有平方啁啾,啁啾参数为0.80,实现了对超短激光脉冲啁啾阶数及量值测量。     

基于节点认证的物联网感知层信息安全传输机制的研究

文章分析了传统物联网信息传输系统在感知层的信息传输的安全问题,应用MD5等算法在采集端点与信息采集节点之间以及信息采集节点与隔离保密节点之间增加身份认证和加密机制,实现感知节点的身份认证和信息加密,使物联网感知层的信息传输更加安全和可靠。     

Design of the low power wake-up receiver for internet of things communication

A wake-up receiver with high energy efficiency and low power consumption is proposed for solving the power consuming problems of wireless nodes communication in the Internet of Things. The proposed wake-up receiver based on the wake-up mechanism can effectively schedule the network nodes communication, and use the simple envelope detection structure to achieve frequency down-conversion, which can flexibly manage energy and reduce power consumption. Based on UMC 65nm CMOS process technology, the wake-up receiver is designed and simulated. The results show that it can achieve S₁₁ of -21dBm and a sensitivity of -75dBm at a data rate of 1Mb/s, when operating at the central frequency of 780MHz and input signal adopting an on-off keying (OOK) modulation, and the power consumption is 82μW at 1.2V voltage supply.