导热系数

The results show that thermal conductivity of SiC is inversely proportional to temperature, and the coefficient of linear expansion is directly proportional to temperature.

结果表明，SiC材料导热系数与温度成反比，其线膨胀系数与温度成正比。

At 20℃ the relationship between thermal conductivity and density of corkboard may be predicted with following equation: Where: K-At 20℃, thermal conductivity of corkboardKcal/m.

寻找软木砖导热系数与容重间内在关系的规律性，在没有准确的实测数据时，用极易测定的软木砖容重，来测算和控制其导热系数值，在生产和工程设计中，具有一定的实用价值。

Based on the exergy transfer equations, exergy transferring in the steady heat conduction process are calculated for the infinite plate at the first type boundary condition, and two results are compared when conductivity is stable and changed with temperature in this paper.

利用一维稳态传递方程，对平壁在第一类边界条件下的一维稳态导热过程的传递做了数值计算，并就导热系数为定值与变值的两种计算结果进行了比较。

According to actual condition, a model of wall thickness of rotary kiln is established. The constant coefficients in the model, including thermal conductivity, heat transfer coefficient, Fourier coefficient and contact resistance, are closely calculated. A formula of contact resistance is draw from a great deal of data of surface and inner temperature of rotary kiln. The wall thickness of rotary kiln is simulated by MATLAB. The simulation result is transmitted from MATLAB to DELPHI through a group of interface functions compiled by VC++. The basic graphs-circle and line are analyzed by the means of the technique of Visualization in Scientific Computing and the Bresenham arithmetic, and are realized the visualization of the wall thickness. The contents of communication between master computer and slaver computer are designed and the error control technique, the idea of multi-thread and the embedded assembly language are applied to realize the temperature data transmission and graph transmission, which largely improved the speed of transmission and the reliability and stability of system.

建立了符合现场实际的回转窑壁厚数学模型；结合现场采用红外测温仪测量所得的温度数据和回转窑的实际结构数据，确定出适合该模型的定常系数(包括导热系数、换热系数、傅立叶系数、接触热阻等)，并得出与回转窑工况的相近的接触热阻公式ln=T~(0.5154)-36.7868；利用MATLAB软件仿真出回转窑壁厚，并将运算结果通过在VC++的编译环境下编译出MATLAB和DELPHI的接口函数传输到该监测系统中，实现了温度数据的转换和交换；运用科学计算可视化技术和Bresenham扫描转换算法对基本图形——圆和直线进行分析，从而实现了仿真后的壁厚数据可视化；在研究异步串行通信方式的基础上，设计了该系统上下位机功能和通信内容，并运用差错控制技术、多线程思想以及嵌入式汇编语言实现了温度数据和图形数据在上下位机之间的远程传输，提高了数据传输的速率和系统的可靠性、稳定性。

Aiming at the laigh thermal conductivity of magnetic refrigerant materials, this paper presents a new technical scheme named vacuum diffusion bonding, which can improve its thermal conductivity. The results indicate that under the condition of temperature ranging from 550℃ to 620℃ in holding time ranging from 30 min to 120 min and a pressure ranging from 12 Mpa to 20Mpa, both Gd and Cu can effectively bond together.

针对室温磁制冷材料Gd本身导热系数低特点，提出了采用真空扩散焊方法改善Gd导热性能的成型工艺方案，在温度为550~620℃，压强为12~20Mpa，保温时间为30~120min条件下，实现了扎和铜异种材料连接，并比较了在锐基体上溅射一层铜薄膜和不溅射薄膜两种条件下的工艺性能。

Aiming at the laigh thermal conductivity of magnetic refrigerant materials,this paper presents a new technical scheme named vacuum diffusion bonding,which can improve its thermal conductivity.

针对室温磁制冷材料Gd本身导热系数低特点，提出了采用真空扩散焊方法改善Gd导热性能的成型工艺方案，在温度为550~620℃，压强为12~20Mpa，保温时间为30~120min条件下，实现了钆和铜异种材料连接，并比较了在钆基体上溅射一层铜薄膜和不溅射薄膜两种条件下的工艺性能。

However, when made of aluminum, the pin fins have only 15%-20% heat transfer coefficients higher than those for the louvered fins, while the pressure drops are not influenced by the material properties.

总换热量取决于翅片材料的导热性能，导热系数越高，针肋的强化作用约明显。本文提出的针肋翅片结构可以用来制造紧凑性更高的换热器。

Research results show that the system performance is influenced greatly by the thermal conductivity of the activated carbon and the contact heat transfer coefficient.

因此为了能得到较高的性能系数和制冷量，首先应该使吸附材料活性炭的导热系数得到提高，其次才是考虑提高接触换热系数。

Thermal conductivity A of mass and single pellet is successively measured by an efficient and steady heating system, of which the heat source is infrared ray. The milli-volt instrument and thermocouple is a way to measure temperature and its of higher precision and has fewer errors. Thermal diffusivity a is researched based on the study of C and. In this thesis, the volume convective heat-transfer coefficient, is measured on the thin-bed drying plat in terms of the principle of cooling machine and the Boyce drying theory, focusing on the air velocity v or mass flux G affecting on h.

导热系数λ的测定采用红外线纵向热流法，热源稳定、效率高；温度采用毫伏表加热偶温度传感器测量，精度高，误差小，并对成堆物料和单个颗粒均作了研究；基于C和λ的测量结果，导温系数α采用公式法计算而得；对流换热系数h_y为体积对流换热系数，其测定是模拟颗粒饲料的冷却干燥过程，依照冷却器的工作原理，构建颗粒薄层干燥试验台，并在Boyce干燥理论的指导下，重点测试了冷却风速对对流换热系数的影响。

Based on the theory of aerothermodynamics for rarefied gas, discusses the principle of compound heat transfer in the vacuum layer.

应用稀薄气体分子热运动理论，研究了真空层复合传热机理，提出了真空层当量导热系数计算方法，分析了不同真空层压力和热媒温度对真空层传热量的影响以及导热、对流和辐射传热量在真空层总传热量中所占比例和变化规律，提出优化真空保温管道保温性能的方法。

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％。