气垫导轨上匀加速度测定的分析

本文对气垫导轨上测量加速度时用平均速度代替即时速度的情况进行了分析讨论。     

Can statistical average be affected by its observer?

In classical statistical mechanics, it is tacitly assumed that the only side effect of the measuring process is to produce fluctuations in the measured system. In other words, the system's average property is not affected by the observer. The present letter discusses this assumption in terms of aGedankenexperiment.     

DOMAIN AVERAGE SCM AND CONSTITUTIVE MODELLING OF POLYCRYSTALLINE AGGREGATES

A theoretical framework for the approximate constitutive assembly of polycrystals,termed henceforth domain average self consistent method, is developed to extend to SCM ofHill to adhered or sliding aggregates of arbitrary grain shape. The legitimacy and usefulnessof the current theory are justified by the polycrystals composed of cubic grains and slidingspherical grains.     

The Curing Process and Elastic Modulus of HTPB-Containing Polyurethanes

By means of the functionality distribution deduced and weight averaged functionality a and molecular size vb2, the sol-gel distribution equations of HTPB(Hydroxyl terminated polybutadiene) + TDI (Toluene-2, 4-diisocyanate) expressed by the model of Aai-B2 type polycondensation were solved and the elastic modulus were calculated. The experimental results of HTPB+TDI curing process indicate that a, vb2 and functionality distribution function are available basically.     

Microwave-assisted extraction of high-molecular-weight hemicelluloses from spruce wood

Microwave-assisted extraction (MAE) at atmospheric pressure has been demonstrated as an efficient technology for the extraction of polymeric hemicelluloses from spruce sawdust. This technology was shown to be more efficient than conventional extraction. MAE leads to a high solubilization of wood and a selective extraction of hemicellulose polymers with high molecular weights. To optimize MAE, different treatment powers (125–573 W) of presoaked spruce sawdust in water and 1 M sodium hydroxide solution for a period of 60 min were tested. The yield of hemicellulose extraction increased with the microwave power in both mediums, but with a clear advantage for presoaked samples in basic medium. The characterization of extracted hemicelluloses has shown high extraction selectivity depending on the medium of impregnation of sawdust before MAE: High-molecular-mass acetylated galactoglucomannans (M_w ∼ 41 kDa) were isolated after presoaking in water and higher molecular mass arabinoglucoronoxylans (M_w ∼ 66 kDa) in basic medium.     

单摆实验中不等精度测量的不确定度分析

以单摆测重力加速度的实验数据处理为例,运用“加权平均”法对不等精度测量的不确定度进行处理,从而使最终测量结果更具合理性和准确性.     

云层背景目标识别的匹配滤波器设计

提出一种利用最大平均相关高度(MACH)算法识别复杂云层背景目标的改进滤波器设计方法。在MACH滤波器设计中,通过对云层背景功率谱的统计特性分析,数据拟合得到云层背景功率谱的分布函数,用以代替传统的白噪声模型;提取飞行目标的姿态变化图像,并作阈值化处理,得到训练样本。对不同云层背景和姿态变化目标的相关识别结果表明:改进滤波器的平均峰值相关能量比为0.71%,峰值鉴别率为0.92,可以有效抑制云层背景的干扰,对姿态变化目标识别的鲁棒性较好。     

Hydration Kinetics for Alkaline Activation of Slag from Color Variation Data

In this study, we explore a new method based on color variation data to derive the kinetics of the entire process of the hydration of alkali-activated slag (AAS). Using this image analysis technique, we can monitor the induction period that cannot be observed using conventional microcalorimetry techniques. Color variation was recorded across a sequence of 9999 images, which were processed via MATLAB software package. Further, an average pixel value (APV) was determined to represent the color in each image. Reaction parameters, such as color variation velocity v(t), reaction speed ε(t), and hydration degree α(t), that govern the entire hydration process were determined. On the basis of the reaction parameters and a Krstulovic–Dabic kinetic model, integral and differential equations were derived to simulate the three basic processes of AAS hydration. Equations describing the reaction kinetics of AAS with solutions of three different concentrations of NaOH were extracted using this method.     

气相渗透法测定数均分子量的仪器常数问题研究

讨论了蒸气压渗透计仪器常数的分子量依赖性问题．通过对某些已知分子量化合物的温差信号随时间变化的研究，提出了测量四个低分子一种改进的ＶＰＯ信号的测量手续和数据处理方式，可以得到更为准确的数均分子量．