移动式太阳辐射热效应系统的设计与应用

GJB 150.7A-2009《军用装备实验室环境试验方法第7部分:太阳辐射试验》规定了军用装备实验室太阳辐射试验的试验要求和试验过程。针对于此标准的要求,本文设计出一款易拆装、可灵活移动的新型移动式太阳辐射热效应试验系统。该系统由步入式高低温实验室、光照度监控系统和整车红外加热系统组成。不仅能满足GJB 150.7A-2009《军用装备实验室环境试验方法第7部分:太阳辐射试验》第4.3.3.1条款“程序Ⅰ”的试验要求还兼顾汽车主机厂的企业标准,如东风汽车等。

沥青路面热反射涂层辐射热效应分析

热反射涂层是应用于路面表面的一种功能层,通过反射阳光减少路面蓄热,从而抑制路面升温。研究分析了自行研制的热反射涂层对环境的辐射效应。通过现场试验,比较分析了热反射涂层的辐射热效应。结果表明:与对照沥青路面相比,热反射涂层的辐射热降低了约2/3,有利于缓解城市热岛效应。

金属板自然环境太阳辐射热效应试验及影响因素分析

本文以不同涂层颜色、不同粗糙度的7075铝合金金属板为试验对象,设计自然环境太阳辐射热效应试验方案,获取不同辐照度下各试验件的温度.得到涂层颜色对试验件热效应的影响规律。针对一线工程师难以掌握数值仿真进行热效应分析的问题,建立一种太阳辐射环境下稳态温度计算算法,具有形式简单、准确度高等优势,可以应用于给定辐照强度下典型材料热效应预测。基于该工程算法,本文分析辐照度、风速两类主要因素对金属板热效应的影响规律。

金属光栅增强石墨烯宽谱响应光电探测器

光电探测器在通信、检测和医疗等领域应用广泛,随着航空航天、夜视、遥感、热成像、汽车互联和消费电子等行业的发展,人们对超宽带探测器的需求也越来越迫切。现有的超宽带探测是使用不同材料、不同探测频段的多个光电探测器,集成度不高,阻碍了上述应用的发展。因此设计了石墨烯微米条–金属光栅复合结构的光电探测器,该器件在太赫兹、红外和可见光波段都可产生光电响应。在可见光范围内,金属光栅将探测器的探测灵敏度从1.1 mA/W显著提高至2.5 mA/W。该研究为基于石墨烯的超宽带光电探测器的设计提供了新的思路。

Entropy analysis of SWCNT & MWCNT flow induced by collecting beating of cilia with porous medium

In this article, we considers the thermodynamics analysis of creeping viscous nanofluid flow in a horizontal ciliated tube under the effects of a uniform magnetic field and porous medium. Moreover, energy analysis is performed in the presence of an internal heat source and thermal radiation phenomena. The thermal conductivity of base fluid water is strengthened by considering the carbon nanotubes (CNTs). Mathematical formulation operated, results in a set of non-linear coupled partial differential equations. The governed differential system is transformed into an ordinary differential system by considering suitable similarity variables. Exact solutions in the closed form are computed for the temperature, momentum and pressure gradient profiles. In this study, special attention is devoted to the electrical conductivity of the CNTs. Streamlines patterns are also discussed to witness the flow lines for different parameters. Thermodynamics analysis shows that entropy of the current flow system is an increasing function of Brinkmann number, magnetic parameter, nanoparticle concentration parameter and Darcy number.

MHD mixed convective stagnation-point flow of Eyring-Powell nanofluid over stretching cylinder with thermal slip conditions

The optimal design of heating and cooling systems must take into account heat radiation which is a non-linear process.In this study,the mixed convection in a radiative magnetohydrodynamic Eyring-Powell copperwater nanofluid over a stretching cylinder was investigated.The energy balance is modeled,taking into account the non-linear thermal radiation and a thermal slip condition.The effects of the embedded flow parameters on the fluid properties,as well as on the skin friction coefficient and heat transfer rate,are analyzed.Unlike in many existing studies,the recent spectral quasi-linearization method is used to solve the coupled nonlinear boundary-value problem.The computational result shows that increasing the nanoparticle volume fraction,thermal radiation parameter and heat generation parameter enhances temperature profile.We found that the velocity slip parameter and the fluid material parameter enhance the skin friction.A comparison of the current numerical results with existing literature for some limiting cases shows excellent agreement.

Quantum Non-thermal Effect From Kerr-Newman Black Hole

We present a short and direct derivation of Hawking radiation by using the Damour-Ruffini method, as taking into account the self-gravitational interaction from the Kerr-Newman black hole, It is found that the radiation is not exactly thermal, and because the derivation obey conservation laws, the non-thermal Hawking radiation can carry information from the black hole. So it can be used to explain the black hole information paradox, and the process satisfies unitary.

Continuous Variable Entanglement of Two Mesoscopic Josephson Junctions Induced by a Thermal Radiation Field

The continuous-variable （CV） entanglement between two mesoscopic Josephson junctions is studied and the time-dependent characteristic function in Wigner representation for the Josephson junction subsystem driven by a singlemode thermal field is analytically obtained. It is found that an initial lowest energy state of the junction subsystem can evolve into a two-mode entangled Gaussian state through the interaction with the thermal radiation field. Furthermore, we investigate the influence of the temperature on the entanglement of the junctions and find that the CV entanglement of the two junctions shows the critical behavior with respect to the temperature.

On the MOSFET-Based Temperature Sensitive Element for Bolometer Application

This paper focuses on the study of thermal performances of MOS （metal-oxide-semiconductor） transistors for uncooled infrared bolometer applications. Such devices can be used in various applications both military and civil, such as defence and security, medical applications, industrial surveillance, etc. Series of measurements were conducted to obtain TCC （temperature coefficient of current） versus gate voltage and temperature curves. The TCC is a figure of merit for a device used as the sensitive element in a bolometer that represents its sensitivity to temperature and as such is a good indicator of the detector attainable performance. The measurements were confronted to Atlas simulations, and showed that in the subthreshold region the TCC ranges from 4%/K all the way to 9%/K which represents a great improvement compared to state of the art thermistor bolometers. Analytic expressions of the TCC are also derived from current equations of the MOSFET （MOS field effect transistor） drain current to help understanding the effect of drain to source voltage, mobility, temperature and threshold voltage sensibility to temperature, in all three operation modes of the transistor （subthreshold, ohmic and saturation）. It was also determined that gate length does not have an influence on the TCC until short channel effects are factored in.

微波辐射下L-氨基酸的快速消旋方法

微波辐射作用下的L氨基酸消旋反应是一种新的氨基酸消旋方法,具有对环境友好的优点。本文报道了在微波辐射下,以1.0molL氢氧化钠水溶液替代有机酸作为反应溶剂,水杨醛为催化剂,水杨醛与L氨基酸的摩尔比为0.1,L-氨基酸可以快速消旋;消旋反应随微波辐射功率的提高而加快,在600W时已接近最大反应速率。同时也讨论了微波作用下L-氨基酸的消旋反应机理。

Sub-ambient full-color passive radiative cooling under sunlight based on effcient quantum-dot photoluminescence

Daytime radiative cooling with high solar refection and mid-infrared emission offers a sustainable way for cooling without energy consumption.However,so far sub-ambient daytime radiative coolers typically possess white/silver color with limited aesthetics and applications.Although various colored radiative cooling designs have been pursued previously,multi-colored daytime radiative cooling to a temperature below ambient has not been realized as the solar thermal effect in the visible range lead to signifcant thermal load.Here,we demonstrate that photoluminescence(PL)based colored radiative coolers(PCRCs)with high internal quantum effciency enable sub-ambient full-color cooling.As an example of experimental demonstration,we develop a scalable electrostatic-spinning/inkjet printing approach to realize the sub-ambient multi-colored radiative coolers based on quantum-dot photoluminescence.The unique features of obtained PCRCs are that the quantum dots atop convert the ultraviolet–visible sunlight into emitted light to minimize the solar-heat generation,and cellulose acetate based nanofbers as the underlayer that strongly refect sunlight and radiate thermal load.As a result,the green,yellow and red colors of PCRCs achieve temperatures of 5.4–2.2℃ below ambient under sunlight(peak solar irradiance>740 Wm),respectively.With the excellent cooling performance and scalable process,our designed PCRC opens a promising pathway towards colorful applications and scenarios of radiative cooling.