Heating and quenching of metastable superconducting compounds with a plasma jet

Superconducting compounds, such as cubic -MoC_1–x, cubic -WC_1–x, hexagonal MoB₂, and cubic -TaN, which are metastable at room temperature, have been formed by heating and quenching of their respective equilibrium phases, such as hexagonal -MoC_1–x, hexagonal WC, rhombohedral Mo₂B₅, and hexagonal -TaN in a plasma jet. From calculations based on a simple model, the quenching rate of particles has been estimated to be 10⁵ deg s^–1.     

程序升温热重法研究扎赉诺尔煤的气化动力学

用程序升温热重法对扎赉诺尔煤（ＺＬ）的８００℃半焦进行ＣＯ２气化研究，考察了升温速率对ＴＧ／ＤＴＧ谱图的影响，分析讨论了ＤＴＧ参数（Ｔｍ和Ｒｍ）的变化；用单一升温速率法和多个升温速率组合法分别作了动力学计算，并对结果进行了分析讨论。结果表明：Ｔｍ和Ｒｍ均随升温速率的增高而增大，两种计算方法得到的动力学参数是不同的，单一升温速率法计算出的表观活化能Ｅ和指前因子Ａ遵循关系式：ｌｏｇＡ＝０．１０Ｅ－８．     

固体材料低温比热测量技术综述

材料低温比热测量对新材料研究和应用具有重要意义,低温比热测量是低温物理研究领域最活跃的研究方向之一。对低温比热测量研究历史作了简单的介绍,对各种低温比热测量方法的原理、应用、发展进行了较全面的综述分析,对超低温、强磁场、放射性样品等特殊情况下比热测量作了讨论。     

温差电技术原理及在工科物理实验中的应用

简要介绍温差电技术的基本原理以及运用该原理设计、制作一些在工科物理实验中的装置。     

A New Approach to Measurement of Heating Rate of Trapped Ions

We propose a new scheme to estimate the heating rate of trapped ions in thermal states. By applying a controlled-U gate between the internal and the motional states of one of the trapped ions, we could obtain the mean phonon number from the population of the internal state of the ion. The imperfection due to fluctuations of the relevant parameters in real experiments is considered and we anaiyze the experimental feasibility of our scheme with sophisticated ion trap techniques.     

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研制了HL-2A装置LHCD和ECRH系统使用的高压电源,其电源拓扑分别为晶闸管交流调压型和星点控制型高压电源,通过高压脉冲调制器给LHCD和ECRH系统供电,采用了波头补偿、前馈和反馈相结合的控制方法,弥补了电源拓扑本身固有的瞬态特性不足和发电机输出的不稳定性,使电源输出电压输出平顶的稳定度优于1%。介绍了高压电源的主回路结构,对高压电源的控制进行了论述,同时给出了实验结果。     

Preparation and characterization of Gd2O3:Eu rods by surfactant assemblies—microwave heating

Gd₂O₃:Eu³⁺ rods were successfully obtained by microwave heating the as-prepared substance, which templated by surfactant assemblies of gadolinium hydroxide and europium hydroxide, formed in a reaction between Gd(NO₃)₃-Eu(NO₃)₃ and urea. Transmission electron microscopy (TEM) characterizations indicated that the synthesized rods with an averaging diameter of 100-150 nm and agglomerates slightly. Powder X-ray diffraction (XRD) results indicated that the resultant rods were cubic Gd₂O₃. The luminescent of Gd₂O₃:Eu³⁺ rods were investigated by photoluminescence (PL). Upon excitation with 257 and 277 nm, respectively, Gd₂O₃:Eu³⁺ rods show a strong red emission line at around 611 nm. Furthermore, this novel method required a very short heating time, thus reducing the energy consumption.     

侧向局部加热对流的周期性

通过流体力学方程组的数值模拟,研究了侧向局部加热条件下Prandtl数Pr=0.0272时流体对流的周期性.结果表明:随着Grashof数Gr的增加,对流按稳态对流、单局部周期对流、双局部周期对流、准周期对流的顺序发展.当Gr<3.6×103时,对流为稳态;在3.6×103相似文献   

Superconvergent estimates of conforming finite element method for nonlinear time‐dependent Joule heating equations

In this article, we study the superconvergence analysis of conforming bilinear finite element method (FEM) for nonlinear Joule heating equations. Based on the rigorous estimates together with high accuracy analysis of this element, mean value technique and interpolation postprocessing approach, the superclose and superconvergent estimates about the related variables in H¹‐norm are derived for semidiscrete and a linearized backward Euler fully discrete schemes, which extends the results of optimal estimates obtained for conforming FEMs in the previous literature. At last, a numerical experiment is performed to verify the theoretical analysis.