弹力型双瓦楞纸板衬垫动态缓冲性能的试验研究

试验研究弹力型双瓦楞纸板衬垫的动态缓冲性能,得到弹力型双瓦楞纸板衬垫在跌落高度分别为30、60、90cm 3种条件下的最大加速度-静应力曲线,并采用最小二乘法和多项式曲线拟合,获得曲线的经验公式.这些结果为弹力型双瓦楞纸板衬垫在缓冲包装中的应用提供了基本数据和重要公式.     

折叠型双瓦楞纸板衬垫动态缓冲特性的试验研究

试验研究了3种折叠型双瓦楞纸板衬垫结构在跌落高度分别为30cm、60cm、90cm 3种条件下的动态缓冲特性,采用3次多项式曲线拟合法获得了峰值加速度-静应力曲线的经验公式和特征系数.这些研究工作对折叠型双瓦楞纸板衬垫在运输包装中的应用具有良好的参考价值.     

瓦楞纸板衬垫缓冲特性研究

简述了常用瓦楞纸板衬垫的结构形式；分析比较了几种典型衬垫的缓冲特性。研究瓦楞纸板的缓冲特性，推广使用瓦楞纸板衬垫，有利于环境保护，回收再生，降低成本。     

瓦楞纸板衬垫缓冲特性研究

简述了常用瓦楞纸板衬垫的结构形式，分析比较了几种典型衬垫的缓冲特性，研究瓦楞纸板的缓冲特性，推广使用瓦楞纸板衬垫，有利于环境保护，回收再生，降低成本。     

液晶显示器缓冲垫绿色设计及有限元分析

目的设计绿色环保的液晶显示器缓冲衬垫,并对其受跌落冲击时的缓冲效果进行有限元分析。方法采用瓦楞纸板折叠成形的方式对液晶显示器的缓冲衬垫进行绿色设计。在ABAQUS有限元软件中建立液晶显示器和缓冲衬垫的实体模型,通过有限元软件模拟液晶显示器运输过程中角跌落的冲击响应,分析缓冲衬垫的缓冲效果。结果角跌落冲击过程中,等效应力云图表明衬垫跌落角处变形较大,应力集中,显示器跌落角处最大应力达到1.293 MPa,但未超过材料的屈服极限。冲击加速度计算结果表明,以1 m的高度跌落时,显示器上易损件的最大冲击加速度为748 m/s2,未超过液晶显示器的许用脆值。结论瓦楞纸板折叠成形的环保缓冲衬垫满足缓冲包装要求,能有效保护显示器抵抗跌落冲击。     

笔记本电脑的纸质缓冲包装设计

目的研究瓦楞纸板缓冲材料包装某品牌笔记本电脑的方法。方法利用Pro/E软件为电脑机身设计3套缓冲衬垫结构,并进行对比分析,确定最佳设计,利用Ansys软件对最佳设计缓冲结构包装件的静态压缩、模态、跌落等特性进行仿真测试分析。结果该缓冲结构衬垫吸收了大部分的应力,模态分析没有发生共振,包装件的加速度峰值小于笔记本电脑的脆值60 g。结论只要缓冲结构设计合理且选配材合适,瓦楞纸板完全能够满足笔记本电脑及类似电子设备的绿色缓冲包装需求。     

X-PLY超强瓦楞纸板动态缓冲特性的试验研究

基于跌落冲击试验,研究X-PLY(A)、X-PLY(B)两种超强瓦楞纸板的动态缓冲性能,获得了动态缓冲特性曲线的经验公式及其特征系数,为X-PLY超强瓦楞纸板在缓冲包装中的推广应用提供了基本数据.结果表明,X-PLY超强瓦楞纸板的动态缓冲特性曲线呈凹谷状,开口向上,只有一个极小值点,冲击加速度波形近似于半正弦波,具有优良的动态缓冲特性,而且X-PLY(A)超强瓦楞纸板的动态缓冲性能比X-PLY(B)超强瓦楞纸板更好.     

组合瓦楞纸板缓冲衬垫的力学性能研究

本文研究了3A型、3B型、BAB型组合瓦楞纸板缓冲衬垫的抗弯性能和平压性能。抗弯试验结果表明,组合衬垫的载荷一挠度曲线可分为4个阶段,依次为瞬时弹性变形阶段、延迟弹性变形阶段、弹塑性变形阶段和屈服塑性变形阶段;从抗弯性能方面考虑,在对瓦楞纸板进行粘接使用时,可以将A型或B型瓦楞自行组合,但最好不要将B型或A型瓦楞与AB型瓦楞组合。平压试验结果表明,在3A型、3B型及BAB型组合瓦楞纸板缓冲衬垫的静态压缩曲线均存在三个峰值,且峰值与瓦楞纸板层数一一对应,各层按照屈服强度从小到大的顺序依次屈服、破坏;从静态压缩性能方面考虑,BAB结构的抗压性能最好,3B结构次之,3A结构最差。根据静态压缩试验绘制的瓦楞纸板缓冲系数-最大静应力曲线,为采用组合瓦楞纸板衬垫进行缓冲包装设计提供了依据。当采用该曲线进行缓冲包装时,应根据产品特性及流通环境特点,尤其是产品或包装件可能给予缓冲衬垫的静压力范围,合理选择衬垫的组合型式。     

0945型瓦楞纸板衬垫缓冲防振性能试验

目的研究0945型瓦楞纸板衬垫三角形支座底部支撑点位置对其缓冲防振性能的影响。方法以0945型衬垫三角形支座的底部支撑点与边缘的水平距离为结构参数,采用B楞瓦楞纸板制作5种0945型衬垫试样,利用静、动态压缩试验、随机振动试验分析衬垫的缓冲防振性能。结果应力-应变曲线表明,当底部支撑点与边缘的距离为40 mm时,衬垫的最大应力达到78 k N;当该距离为0时,衬垫的单位体积应变能达到35.67 k J/m3。最大加速度-静应力曲线表明,40 mm时衬垫的最大加速度最小。随机振动功率谱密度曲线表明,距离为0时,衬垫的功率谱密度峰值最小。结论 0945型瓦楞纸板衬垫三角形支座为直角三角形时,垂直边能承受较大载荷,产生较小变形,不易塌陷,缓冲防振性能最好。     

大型家电全瓦楞纸板缓冲包装结构设计

全瓦楞纸板缓冲包装在小型产品上应用较多,而在大型产品上应用较少。首先测试了5种楞型瓦楞纸板的力学性能参数,制作了4种瓦楞结构并对其静态和动态缓冲性能进行了测试。在此基础上,以海尔XQB45-10B波轮洗衣机为例,基于产品的基本参数和流通环境,设计并制作了海尔洗衣机的全瓦楞纸板缓冲包装。该设计方案通过了实验室安全性测试,证明了使用瓦楞纸板代替塑料缓冲包装材料的可行性。为在大型产品上推广应用全瓦楞纸板缓冲衬垫提供了参考。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Assessment of intakes of mixtures of radionuclides

Australia has several uranium mines and a large number of mineral sand mines, with associated processing facilities. Exposures resulting from these mining and processing operations usually involve intakes of mixtures of radionuclides. This work describes the development of a suite of first order, linear compartment models, based on the ICRP Publication 66 respiratory tract model, and an analytical solution to the decay equations, for assessing the consequences of such intakes. The computer programs based on these models directly compute excretion, organ retention and organ and whole-body doses for intakes of either single radionuclides or any mixture of radionuclides belonging to the same radioactive decay chain. The intake can be via inhalation, ingestion or injection, and can be acute, chronic or of limited duration. The starting concentration and degree of secular (dis)equilibrium can be specified for each radionuclide. No assumptions need to be made about the relative magnitudes of the radioactive half-lives of the different nuclides.     

卧式金属罐容量的测量结果不确定度

本文根据多年的实践检定经验 ,参照JJF1 0 59- 1 999《测量不确定度评定与表示》以及《测量不确定度表达 1 0讲》 ,对卧式金属罐容量的测量结果不确定度进行了评定。     

盐酸浓度不确定度的评估

通过对盐酸浓度标定的过程分析，找出影响结果的各个分量，进行不确定度的评定，按照计量技术规范给出标准的表示法。     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of anisotropy of properties on the basis of studies of texture of coarse-grained ingots of thermoelectric materials

An analysis of anisotropy of the properties of a Bi₂Se_0.3Te_2.7 solid solution was carried out using construction of demonstrative surfaces for thermoelectric effectiveness and thermal expansion coefficients. It is shown that the texture is an important factor forming anisotropy of properties and technological fitness of ingots for manufacturing modules. Anisotropy of properties based on the studies of the ingot textures obtained using the float-zone method and Bridgman method (growing thermoelectric plates in a flat cavity) was studied.