微型生化分析仪样品室温度控制系统研究

结合微型生化分析仪样品室的要求,设计了一种基于单片机的微型生化分析仪样品室温度控制系统.它以AT89S51为核心,采用单总线高精度数字温度传感器DS18B20对样品室温度采样,同时利用汇编语言编写温度设定与控制程序,采用半导体制冷的方式,实现了温度在25℃、30℃、32℃和37℃四个温度值的稳定,控制精度达±0.5℃.     

蓄冰空调制冷新技术

文章叙述了中央人民广播电台新业务楼空调工程中采用蓄冰空调制冷新技术的情况。文章讲解了蓄冰空调原理，并对蓄冰制冷与常规制冷技术进行比较，指出：从节电上来考虑，前者具有经济性。文章最后列举了今后在设计和维护上，还有待解决的一些问题。     

X波段盘圈加速结构热阴极微波电子枪的研究

介绍了采用盘圈(DAW)加速结构在11.43GHz下研制的热阴极微波电子枪注入器，分析了注入器中DAW加速结构支撑杆对于微波特性的影响以及加速结构中的模式重叠问题. 针对该结构的强腔间耦合以及次临近耦合不能忽略的特点，对其调谐方法进行了分析研究.给出了该长腔链热阴极微波电子枪注入器的物理设计及粒子动力学计算结果，电子能量为5—6MeV，脉冲流强为40mA，电子束发射度为3.4πmm.mrad. 该微波电子枪的加工焊接已经完成，文中给出了其冷测结果.     

The investigation of the (p,ρ,T) and (ps,ρs,Ts) properties of {(1−x)CH3OH + xLiBr} for the application in absorption refrigeration machines and heat pumps

The (p,ρ,T) and (p_s,ρ_s,T_s) properties of {(1−x)CH₃OH + xLiBr} over a wide range of state parameters are reported for the first time. The experiments were carried out in a constant volume piezometer over a temperature range from 298.15 K to 398.15 K, at 0.08421, 0.13617, 0.19692, 0.23133 and 0.26891 mole fractions and from atmospheric pressure up to 60 MPa. The experimental uncertainties are ΔT=±3 mK for temperature, Δp=±5·10⁻² MPa for high pressure and Δp=±5·10⁻⁴ MPa for atmospheric pressure, Δρ=±3·10⁻² kg · m⁻³ for density. An equation of state was derived for correlation of the experimental data of the solutions.     

A Matter of Size and Stress: Understanding the First‐Order Transition in Materials for Solid‐State Refrigeration

Solid‐state magnetic refrigeration is a high‐potential, resource‐efficient cooling technology. However, many challenges involving materials science and engineering need to be overcome to achieve an industry‐ready technology. Caloric materials with a first‐order transition—associated with a large volume expansion or contraction—appear to be the most promising because of their large adiabatic temperature and isothermal entropy changes. In this study, using experiment and simulation, it is demonstrated with the most promising magnetocaloric candidate materials, La–Fe–Si, Mn–Fe–P–Si, and Ni–Mn–In–Co, that the characteristics of the first‐order transition are fundamentally determined by the evolution of mechanical stresses. This phenomenon is referred to as the stress‐coupling mechanism. Furthermore, its applicability goes beyond magnetocaloric materials, since it describes the first‐order transitions in multicaloric materials as well.     

Thermomagnetic properties of very heavy fermions suitable for adiabatic demagnetisation refrigeration at low temperature

ABSTRACT

With the aim to improve the performance of classical paramagnetic salts for adiabatic refrigeration processes at the sub-Kelvin range, relevant thermodynamic parameters of some new Yb-based intermetallic compounds are analysed and compared. Two main applications are considered: (i) those requiring temperature fixed-points to be reached applying magnetic fields of moderate intensity for satellite applications, and (ii) those which can be used for controlled thermal drifts in laboratory applications. Different thermomagnetic trajectories of the entropy are identified depending on respective specific heat behaviours and the constraints imposed by the Nernst postulate at the sub-Kelvin range. Some simple relationships are proposed to compare the diverse magnetocaloric characteristics of different systems. This procedure allows to include the classical Cerium-Magnesium-Nitride (CMN) salt in that comparison.     

蒸汽压缩式制冷循环教学实验台的研制

为改进机械式实验仪器,即蒸汽压缩式制冷循环实验台的性能缺陷,设计了基于STM32F103的数据采集板卡,提高数据采集的精度和稳定性;采用基于C#语言的实验软件并结合ASP.NET技术实现实验过程自动化和远程实验教学功能。在此对上述功能的实现过程进行必要的阐述并对实验台的重要性能指标不确定度进行了详细的分析。结果表明实验台能满足现有教学实验要求,并对同类实验装置的研发具有一定的参考价值。     

动态红外景像仿真技术综述及帕尔贴效应的应用

在进行红外探测系统测试和评估经常使用红外动态景像仿真系统,随着红外探测技术的发展,红外动态景像仿真系统的性能也亟待提高.首先介绍了目前红外动态景像仿真系统的相关技术要求,然后介绍了悬浮薄膜电阻阵列、红外液晶光阀、薄膜黑体腔和激光二极管阵列这4种典型器件的工作原理及其优缺点;提出了一种基于帕尔贴效应的红外动态景像仿真技术,并对其进行了理论分析,指出该技术具有动态范围大、帧频高、分辨率高、均匀性好、双向仿真的优点.