水+3-甲基吡啶+溴化钠三元溶液临界跨接现象

采用折射率法在较宽温度范围内研究了溴化钠、3-甲基吡啶和水的临界质量分数分别为0.240、0.192和0.568体系的临界性质, 发现在近临界点临界指数为0.365, 与Fishe重整化值一致. 有效临界指数随着温度逐渐远离临界点, 从0.365下降到0.20左右, 但当排除了“正规项”的影响后, 展现出向平均场理论值0.5单调跨接的行为.     

Etude Experimentale et Modelisation des Equilibres Solide—Liquide du Systeme Binaire H2O—UO2(NO3)2

The binary system H₂O—UO₂(NO₃)₂ was studied by solubility measurements and constant heat flow thermal analysis. Temperature and composition of the eutectic transformation between ice and uranyl nitrate hexahydrate were accurately defined. A new hydrate with 24 molecules of water decomposes at –21°C according to the peritectoid reaction<UO₂(NO₃)₂·24H₂O> <UO₂(NO₃)₂·6H₂O> + 18<H₂O>The quasi-ideal model was applied to the solid—liquid equilibria, using the following reaction hypothesis:((UO ₂ ²⁺ )) + 2((NO ₃ ^– ))+ h((H₂O)) ((UO₂OH⁺aq)) + ((H₃O⁺aq + 2((NO ₃ ^– aq))A complete calculation of the binary system was carried out with a global ionic hydration number h equal to 9 in the aqueous solutions. It allowed to the melting enthalpies of uranyl nitrate hydrates.

This revised version was published online in November 2005 with corrections to the Cover Date.     

Evaluation of the parameters of the Bender equation of state for low acentric factor fluids and carbon dioxide

Volumetric properties of several low acentric factor fluids (Ar, CH₄, C₂H₆, Kr, N₂, Ne, O₂, Xe) as well as CO₂ are modeled using the Bender equation of state. This equation is a linear function of 19 adjustable parameters, which are evaluated from properties data, using a linear numerical procedure. The validity of the EOS is tested by calculating the Joule-Thomson inversion curve. A simple model is in particular used to correlate the inversion properties predicted by the Bender equation, expressed in term of reduced pressure as a function of reduced temperatures ranging from 0.8 to 6. The simple correlation reproduces accurately the used data. We employ data on state behaviour ρ(P,T) of homogeneous fluid phases, vapour-liquid equilibrium, second virial coefficient and the coordinates of the critical point.     

一般增长曲线模型参数阵的BLU估计

考虑一般增长曲线模型：Ｙ＝Ｘ１ＢＸ２＋εＥ（Ｖｅｃ（ε））＝０Ｖ（Ｖｅｃ（ε））＝σ２ＶＩｎ（Ｖ０）本文对任一可估函数ＫＢＬ给出了它的ＢＬＵ估计（最佳线性无偏估计），并得到了方差σ２的一个无偏估计．     

Quantum Circuit Optimization for Solving Discrete Logarithm of Binary Elliptic Curves Obeying the Nearest-Neighbor Constrained

In this paper, we consider the optimization of the quantum circuit for discrete logarithm of binary elliptic curves under a constrained connectivity, focusing on the resource expenditure and the optimal design for quantum operations such as the addition, binary shift, multiplication, squaring, inversion, and division included in the point addition on binary elliptic curves. Based on the space-efficient quantum Karatsuba multiplication, the number of CNOTs in the circuits of inversion and division has been reduced with the help of the Steiner tree problem reduction. The optimized size of the CNOTs is related to the minimum degree of the connected graph.     

基于光谱曲线形态的高光谱影像检索方法研究

随着传感器技术、数据通讯技术的飞速发展,利用各种机载和星载传感器,己经获取到各种不同的海量遥感影像数据。巨大的数据量带来了数据存储和管理的问题,如何实现从海量影像数据中检索出我们所需要的信息显得十分迫切。影像检索最早由Chang于1980年提出,是对传统信息检索的扩展。针对海量遥感影像高效检索的需求和高光谱遥感影像波段数目多的特点,分析了影像检索中的影像距离函数和相似性度量问题,基于经典的曲线简化Douglas-Peucke算法(简称DP算法)提取光谱曲线的形态特征,利用“提取特征”的思想,提出了基于DP算法的光谱曲线和影像检索(简称DPSR)方法,将光谱形态特征应用于影像检索当中。DPSR利用光谱曲线上的特征点,减小了计算量,实现了有效地匹配和检索,适合高光谱遥感影像的光谱检索。文章选择了OMISI高光谱数据的四种易混分地类进行了相似性度量的对比实验。通过与常规的分析方法光谱角匹配(SAM)、光谱信息散度(SID)的对比可以看到,DPSR在较少计算量的情况下能保持较高的计算精度,提供了一种新的影像光谱高效检索方法。此外,文章还提出了尚待进一步研究的问题。     

一种排气式膛压模拟装置

为了在实验室条件下简洁、高效地获得与实际相符的膛压曲线,进而开展典型结构和材料膛压载荷响应特性研究,提出了压力舱内发射药燃烧同时发射药气体由排气件排出的膛压模拟装置。结合发射药燃烧理论和等熵流动模型,建立了排气式膛压模拟过程的数学模型。基于理想气体假设,利用Fluent软件模拟泄压过程质量流量规律,并与理论结果对比,确定了流量系数。分别根据76和155 mm火炮膛压曲线特点及小型化设计原则,对模拟装置性能参数进行了优化设计。优化结果表明,获得的压力曲线的增压速率和降压速率基本满足要求,峰值压力达到300 MPa,压力大于30 MPa历时10 ms以上。验证实验结果表明：压力曲线有良好的重复性,且与理论结果一致,装置工作可靠性高;以排放发射药气体方式模拟膛压曲线是可行的。

     

PTFE材料在高应变率冲击下的力学性能

聚四氟乙烯(PTFE)在高速碰撞或者爆炸加载时的应变率可高达10⁶ s^-1,高应变率下PTFE材料的力学响应会对其材料性能产生较大影响。本文中采用压剪炮试验系统(PSPI)测试了PTFE材料在高应变率(10⁵~10⁶ s^-1)下的压缩力学性能,实验中碳化钨(WC)飞片板以一定速度撞击由前靶板、试件和后靶板组成的三明治结构,并采用激光干涉仪记录后靶板自由面的速度变化。对实验结果处理后得到该PTFE材料的应力应变数值,并拟合得到应力应变曲线。本研究对PTFE/金属复合材料制成的动能侵彻体强度及其冲击碎化机理的分析具有指导意义。

     

定积分法求解弯曲变形问题

本文采用定积分方法求解梁的弯曲变形问题。该方法不需要采用边界条件来确定积分常数,有效地简化了问题的求解过程;该方法以梁的转角微元为逻辑起点,清晰地刻画了梁弯曲变形的累加过程,便于深刻理解载荷作用下梁的变形历程。