导热系数

Thermal conductivity is measured by the transient hot-wire method, which shows that the thermal conductivity increases with the increase of nanofluid particle volume fraction and temperature. The thermal conductivity of 0.3vol% SiO2-water nanofluid increases by 11.5% at 25℃, while it increases by 46.5% at 50℃ when compared with water at the same temperatures.

采用瞬态热线法测量纳米流体的导热系数，结果表明：纳米流体导热系数的变化与纳米颗粒体积分数和温度的变化成正比，其中25℃时体积分数为0.3%的SiO2-水纳米流体相对于水的导热系数提高11.5%，而在50℃时则提高46.5%。

The heat generation curves of seven rubber materials used in tires with the changes of temperature have been obtained by using Dynamic Mechanics Analysis technique on NETZSCH DMA242 instrument, knowing that the heat generation of every other rubber materials except inner liner rubber changes lightly alone with the temperature within 10℃～80℃. According to the Fourier law, the heat transfer coefficients of tire rubber are measured by stable method on self-made experiment instrument. The coefficients changes lineally within 20℃～80℃ and the relation formulas λ=λ〓+bt are given out attached with λ〓 and b. The specific heat of tire rubber are measured on Differential Scanning Calorimeter NETZSCH DSC204 and the relations with temperature are linear and the formula is c=c〓+bT, where c〓 and b gained from experiment result data are presented in the paper. The heat convection coefficients on the surface of rolling tire are measured according to the principle of heat-mass transfer analogy principle after simplifying rolling tire into rotating disk with straight movement on wind channel. The relation with rotation speed of disk is linear as h=5. 399+0.0258n and the relation with straight line speed of tire is linear too, h=

论文采用动态力学分析技术，使用NETZSCH DMA 242型实验仪，获得了轮胎用七种胶料的生热率随温度变化曲线，确知除内衬层胶以外，其它各种胶料在一般胎温范围内（10℃～80℃）的生热率随温度变化不大；轮胎胶料的导热系数根据傅立叶定律的基本原理，采用稳态法在自行搭建的实验台上进行测试，结果表明，材料的导热系数在20℃～80℃的温度范围内随温度呈线性变化，论文给出了各种材料导热系数的线性变化的关系式λ=λ〓+bt及其λ〓和b的值；轮胎胶料的比热运用差式扫描量热原理，在NETZSCH DSC204型DSC实验仪上进行测试，结果表明，胶料的比热随温度的变化呈线性变化，其关系可用c=c〓+bT表示，文中给出了根据实验数据拟合的c〓、b的值；对轮胎表面的对流换热系数的测定，本文先将滚动的轮胎简化为有直线运动的旋转圆盘，而后采用萘升华热质比拟技术，在风洞中测量了滚动轮胎表面的对流换热系数，结果表明，圆盘表面对流换热系数与转速呈线性关系，即h=5.399+0.0258n，轮胎表面对流换热系数与其直线运动的速度呈线性关系，即h=

After comparing with the thermal conductivity under two different conditions, the thermal conductivity with vacancy is lower than that with Kr, which accounts for phonon scattering on impurities due to lattice strain is stronger than that due to differences in mass between the defect and the surrounding matrix.

模拟结果显示，温度在20~80K之间，考虑热膨胀时的导热系数比晶格常数固定时的值要低，但随温度变化的关系更加接近实验值时的情况；比较固体氩中不同掺杂时导热系数大小，发现同样掺杂浓度条件下，掺空穴时材料导热系数比掺氪时低，说明掺杂时由于晶格不匹配引起的声子散射比不同质量引起的散射更重要。

First by testing the practical multilayer insulation in a cryogenic tanker, which is the carilometer in my paper,some affecting factors on multilayer insulation are analysed, then by using the low-temperature and vacuum environment caused by multilayer insulation, the effective thermal conductivity of multiple fiber paper with 5 layers is tested.Through Newton interativemethod,an empirical formula is deduced to computer the thermal conductivity of fiber paper,The errors between experimental thermal conductivity and the calculated conductivity by empirical formula are below10%,so the formula of fiber conductivity can be applied to practical enginnering.

为探索改善工程应用中高真空多层绝热层绝热性能的方法，本文实验研究中首先测量了包扎在实际低温储罐上不同结构的高真空多层绝热层的绝热性能，并分析了环境温度、环境压力，层数、不同隔热材料的组合等因素对工程应用中的高真空多层材料绝热性能的影响；然后利用多层绝热层中的低温真空环境测量5层干法纸在不同温度区间内的表观导热系数，在有限实验数据的基础上用牛顿迭代数值拟和出计算5层干法纸表观导热系数的经验公式，对比经验公式计算值和实验测量值，发现二者的误差在10%以内，因此在工程应用中可用本文的经验公式计算干法纸在低温下的导热系数。

Used traditional measurement equipment and a new method-optimal approximation between measured and numerical calculation values, the coefficient of thermal conductivity of cornea was measured. It can be expressed by the equation of λ=0.10395+2. 75156×10〓t.

本文在不改变现有传统测定设备的前提下，采用一种新方法—通过数值计算角膜表面温度变化规律与实测值之间的最佳逼近，确定物体变物性导热系数的参数估算方法，对角膜的导热系数进行了测定，在角膜冻干的温度区间内，角膜的导热系数可近似地表示为λ=0.10395+2.75156×〓。

In this paper mainly predictive expressions for porous materials are described.The thermal conductivities of rock wool and calcium silicate insulating materials havebeen calculated by these expressions,however,it has been found that there is somedeviation of calculated values from measured data for these insulating materialscontaining structural water.The effect of the structural water on thermal conductivityhas been studied by means of TG-DTA curves of rock wool and calcium silicateinsulating materials,and...

本文介绍了预测多孔材料导热系数的主要计算方程，通过岩棉保温材料和微孔硅酸钙保温材料导热系数的预测，指出这些方法在预测含有结构水的微孔硅酸钙保温材料导热系数时，与实测值会有较大的偏差，进而利用岩棉和微孔硅酸钙保温材料热重和差热曲线，研究了材料结构水对其导热系数的影响，提出了预测含有结构水的多孔材料导热系数的修正方法，其结果与实测值相当吻合。

This article analyses the application conditions of freezing method, current research status and the problems in this field. It points that it's necessary to study deep freezing temperature field deeply and discusses the factors which influence the freezing wall such as soil's nature, moisture content, geological conditions, etc. It introduces the theory, process of freezing method, the distribution of temperature field of freezing method and key thermotics parameters influencing freezing temperature field. It simplifies the deep freezing temperature field model. Through ANSYS, this article founds the deep freezing temperature field model, and simulates the field on vary heat conductivities. It analyzes the results of ANSYS simulation, gains the theoretical value of thermometric holes which is needed by back-analysis. Using the simulation temperature and actual value, it gets the equivalent heat conductivity. Then it solves the deep freezing temperature field by the equivalent value, simulates the freezing wall development process and temperature change curve. Against the actual project, the results are favorable.

文中分析了冻结法施工的应用条件，目前对冻结法施工的研究现状和在此领域内存在的问题，指出了对深土冻结温度场进行深入研究分析的必要性；对影响冻结壁形成发展的因素如冻土土性、含水量、地质条件及施工方法等因素进行了论述；对冻结法施工的原理、过程，冻结法温度场的分布情况，影响冻结温度场分布的主要热学参数进行了综述；对深土冻土温度场模型进行了合理的简化，通过ANSYS大型有限元分析软件，建立了深土冻结温度场的模型，对不同导热系数情况下的深土冻结温度场进行了模拟；对ANSYS的模拟结果进行了定性的分析，通过对ANSYS结果的后处理取得了反分析时需要用到的测温孔理论温度值；经过对测温孔模拟温度值和实测温度值的分析，得到了冻结温度场的等效导热系数；使用等效导热系数对深土冻结温度场进行了求解，模拟了冻结壁发展情况和温度场中的温度变化曲线，用所得结果对比工程实际情况，取得了较好的效果。

Different compound adsorbents thermal conductivities were measured at different adsorption capacities.It got these conclusions: At the same adsorption capacity,the compound adsorbents thermal conductivities increase with the quantities of the silicate sol contents increase.The compound adsorbents thermal conductivities increase sharply during the silicate sol contents vary between 0%～(7.5%).The therm...

试验结果表明：在同一吸附量的情况下，导热系数与其添加的粘结剂含量正相关，并且在w=0%~7.5%的添加粘结剂范围内导热系数随着粘结剂含量增加而显著增加；13X沸石原粉、复合吸附剂样品Z1和Z2的导热系数随其吸附量增加呈近似线性增长，当吸附量从0%增加到25%时，各吸附剂导热系数均增加了150%以上；配置出复合吸附剂Z1和Z2在分别添加w=5.0%和7.5%的添加剂下，平均导热系数分别为0.183和0.199 W/，比13X原粉分别提高65.4%和80.1%；将配置的复合吸附剂Z2应用于太阳能冷管，其制冷系数COP约为

In first, a new short time formula of one dimension heat conduction differential equation, based on the theory of one dimension transient method, is presented for thermophysical property measurement of wood. The result of testing on red pine and larch wood arc satisfied by new method.In succession, the relationship between heat conductivity of wood and moisture, density, porosity, temperature and grain is studied experimentally in the range from 25 to 100℃. The result shows that, the heat conductivity is in direct proportion to density. but in inverse proportion to porosity. The heat conductivity of air-dried wood increased probably linear with the temperature rising. And that heat conductivity along the grain of wood is higher than that cross the grain. The former is 1.8 or 2 times of the latter.

文中研究了25～100℃范围内，气干木材的导热系数与含水率、密度、孔隙率、温度及热流方向的关系，研究表明：木材导热系数与密度成正比关系，与孔隙率成反比关系：对于针叶材，导热系数与密度及孔隙率成线性变化关系，而对于阔叶材其变化关系近似成二次曲线；气干木材的导热系数随着温度的升高近似呈线性增加：热流平行于纹理方向的导热系数大于垂直于纹理方向的导热系数，两者的比值大约在1.8～2之间。

The research result indicates that the thermal conductivity of the Cement PO42.5 is slightly higher than that of the PO32.5 and the thermal conductivity of the borehole backfills increases when the sand size increases,and that contained quartz sand is higher than river sand.At the same time,the thermal conductivity of the borehole backfills increases firstly and then decreases and the consistency decreases when the bentonite content increases.

研究发现：PO42.5水泥的导热系数稍大于PO32.5的导热系数，回填材料导热系数随砂子粒径的增大而增大，骨料为石英砂的回填材料导热系数要明显大于骨料为河砂的导热系数；同时回填材料的导热系数随膨润土含量的增加先增加后减小，回填材料的流动性随膨润土含量的增加有所降低。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。