基于WO3和NiOx的单基片全无机智能窗器件的快速制备及其性能的研究

介绍了利用磁控溅射和一种液氮冷却装置,制备非晶态WO3薄膜、非晶态LiNbO3薄膜和纳米微晶态NiOx薄膜的有效方法.进而,使用这种液氮冷却装置,采用全程基片冷却方法,制备了单基片无机全固态智能窗--G│ITO│NiOx│LiNbO3│WO3│ITO器件.实验结果表明,在400～800nm的可见光范围内,该器件经过1000次循环后,它的漂白态透射率为63.0%,而着色态透射率为10.6%,这一初步工作表明,基片冷却方法应该是制备有优异性能的无机全固态电致变色智能窗的有效方法.     

Visualization study of the interface between superheated He II and superheated He I in a two-dimensional narrow channel by using the shadowgraph method

Dynamic behavior of superheated He II-superheated He I interface as a result of heating in a narrow channel between parallel walls that simulates cooling channels of superconducting magnets was investigated using a shadowgraph visualization method. It was confirmed that a superheated state could be created in the narrow channel without preparing a special calm environment. A superheated He II-superheated He I interface transiently appeared between 2.0 K and lambda temperature when applying a small heat flux. The boiling state accompanying the superheated He II-superheated He I interface was repeatedly generated and collapsed. This boiling mode was anticipated to have a high heat transfer coefficient.     

Solubility of nitrogen in one-component refrigerants: Prediction by PC-SAFT EoS and a correlation of Henry’s law constants

Even small amount of non-condensable gas - mostly air or nitrogen - present inside a compression refrigerating circuit may decrease the efficiency of the cooling system. So far, a quantitative assessment of the effect of dissolved gases on the cooling circuit performance is hindered by unavailability of suitable thermodynamic models. In this study, we analyzed the solubility of nitrogen in the following refrigerants: hydrochlorofluorocarbons (HCFC) R22, R123, R124; hydrofluorocarbons (HFC) R23, R32, R125, R134a; perfluorocarbons (PFC) R14, R116, R218, R-3-1-10; and hydrocarbons (HC) R290, R600a. Perturbed-Chain (PC) Statistical Associating Fluid Theory (SAFT) and its modification for polar fluids PCP-SAFT were used to model the temperature dependence of the Henry’s law constant of nitrogen. A simple correlation of the Henry’s law constants valid over large temperature ranges was developed, suitable for assessment of the adverse effects of dissolved nitrogen (and approximately air) on the performance of compression cooling systems.     

冷冻除湿机状态监测试验系统的设计与实现

阐述冷冻除湿机状态监测试验系统的设计方案，介绍试验平台的测点布置和传感器的选择安装，以及数据采集系统的硬件软件，最后给出一监测数据实例，表明该系统能够达到对除湿机状态监测的目的。     

风机盘管新风终状态点的处理分析

从新风处理过程中的焓差和需要的泠水温度两个方面来分析风机盘管新风系统的处理终态点，通过比较和分析几个有代表性的状态点，从中得出在实际过程中最佳的一种终态处理点，以供设计工作中参考和借鉴。     

PET固相缩聚装置切片及粉尘结晶行为分析

采用差示扫描量热(DSC)方法研究了聚对苯二甲酸乙二酯(PET)固相缩聚工艺过程中切片及粉尘的结晶熔融及降温结晶行为,研究表明,切片与粉尘呈现出不同的结晶行为,切片随工艺过程的进行,特性黏度增加,降温结晶能力减弱;而粉尘特性黏度增加的幅度更大,降温结晶能力增强;预结晶及结晶粉尘因摩擦形成了更高熔融温度(267.5℃)下的结晶;高的无机杂质的浓度,促进了粉尘的降温结晶成核;粉尘高的结晶能力,易造成后产品加工过程形成结晶斑点。     

水源热泵系统的稳态模拟与实验研究

建立了水源热泵机组的稳态模型,分别对制冷、制热工况进行了模拟,并在一个名义制冷量为25kW的水源热泵机组实验台上进行了稳态工况的测试,对机组的性能随冷却水、冷冻水入口水温的变化情况做了研究,验证了数学模型的正确性并获得了一些有益的结论.     

Why a Condensate Can Be Thought of as Having a Definite Phase

We present an argument for assigning a definite phase to an assembly of Bose-Einstein Condensed atoms. This relies on the demonstration that a coherent state of the condensed system is a robust state in the presence of interactions between the condensate and its environment.     

Electrocaloric Materials for Solid‐State Refrigeration

The electrocaloric effect (ECE) in dielectric materials has great potential in realizing solid‐state cooling devices with compact size and high efficiency, which are highly desirable for a broad range of applications. This paper presents the general considerations for dielectric materials to achieve large ECE and reviews the experimental efforts investigating ECE in various polar dielectrics. For practical cooling devices, an ECE material must possess a large isothermal entropy change besides a large adiabatic temperature change. We show that polar dielectrics operated at temperatures near order–disorder transition have potential to achieve large ECE due to the possibility of large change in polarization induced by electric field and large entropy change associated with the polarization change. We further show that indeed the ferroelectric poly(vinylidene fluoride–trifluoroethylene)‐based polymers display a large ECE, i.e., an isothermal entropy change of more than 55 J (kgK)^?1 and an adiabatic temperature change of more than 12 °C, at temperatures above the order–disorder transition.     

Bennett clocking of quantum-dot cellular automata and the limits to binary logic scaling

We examine power dissipation in different clocking schemes for molecular quantum-dot cellular automata (QCA) circuits. 'Landauer clocking' involves the adiabatic transition of a molecular cell from the null state to an active state carrying data. Cell layout creates devices which allow data in cells to interact and thereby perform useful computation. We perform direct solutions of the equation of motion for the system in contact with the thermal environment and see that Landauer's Principle applies: one must dissipate an energy of at least k(B)T per bit only when the information is erased. The ideas of Bennett can be applied to keep copies of the bit information by echoing inputs to outputs, thus embedding any logically irreversible circuit in a logically reversible circuit, at the cost of added circuit complexity. A promising alternative which we term 'Bennett clocking' requires only altering the timing of the clocking signals so that bit information is simply held in place by the clock until a computational block is complete, then erased in the reverse order of computation. This approach results in ultralow power dissipation without additional circuit complexity. These results offer a concrete example in which to consider recent claims regarding the fundamental limits of binary logic scaling.     

Thermal behavior of a cryogenic loop heat pipe for space application

This paper discusses a prototype of cryogenic loop heat pipe (CLHP) working around 80 K with nitrogen as the coolant, developed at CEA-SBT in collaboration with the CAS/TIPC and tested in laboratory conditions. In addition to the main loop it features a pressure reduction reservoir and a secondary circuit which allow cooling down the loop from the room temperature conditions to the nitrogen liquid temperature and transferring the evaporator heat leaks and radiation heat loads towards the condenser. The general design, the instrumentation and the experimental results of the thermal response of the CLHP are presented, analyzed and discussed both in the transient phase of cooling from room temperature (i) and in stationary conditions (ii). During phase (i), even in a severe radiation environment, the secondary circuit helped to condense the fluid and was very efficient to chill the primary evaporator. During phase (ii), we studied the effects of transferred power, filling pressure and radiation heat load for two basic configurations of cold reservoir of the secondary circuit. A maximum cold power of 19 W with a corresponding limited temperature difference of 5 K was achieved across a 0.5 m distance. We evidenced the importance of the filling pressure to optimize the thermal response. A small heating power (0.1 W) applied on the shunted cold reservoir allows to maintain a constant subcooling (1 K). The CLHP behaves as a capillary pumped loop (CPL) in such a configuration, with the cold reservoir being the compensation chamber of the thermal link. The radiation heat loads may affect significantly the thermal response of the system due to boiling process of liquid and large mass transfer towards the pressure reduction reservoir.     

Quantum Fluctuations of Mesoscopic Damped Circuit Involving Capacitance-Inductance Coupling at a Finite Temperature

The quantization of mesoscopic damped circuit involving capacitance-inductance coupling is proposed by the method of thrice linear transformation and damped harmonic oscillator quantization. The quantum fluctuations of the charges and current of each loop are calculated by thermo-field dynamics (TFD) in thermal vacuum state, thermal coherent state and thermal squeezed state, respectively. It is shown that the quantum fluctuations of the charges and current not only depend on circuit inherent parameter and coupled magnitude, but also rely on squeezed coefficients, squeezed angle, environmental temperature and damped resistance. And, because of influence of environmental temperature and damped resistance, the quantum fluctuations increase with increasing temperature and decrease with prolonging time.      

小型数据中心机房布局及气流组织研究

以实际项目的机房为例,通过CFD模拟的方法研究小型机房的合理布局形式,分析各形式下的温度和速度分布情况,利用热环境评价指标来评价冷却效果,并对刚投入使用的机房进行了实验测试。研究表明,敞开式冷热通道的两侧和顶部都存在冷热空气掺混现象,降低了冷空气的利用效率;在机房尺寸允许的情况下,空调送风方向应与冷热通道平行,布置机架时应尽量增加每排的机柜数量;当机房发热量较小时,冬季室外空气的自然冷量可以满足冷却要求;封闭冷通道的方式可以减少冷空气短路,提高冷却效率。     

Modified friction factor correlation for CICC’s based on a porous media analogy

The first cool-down of the EDIPO (European DIPOle) test facility is foreseen to take place in 2011 by means of the existing 1.2 kW cryoplant at EPFL-CRPP Villigen. In this work, the thermo-hydraulic analysis of the EDIPO cool-down is performed in order both to assess the its duration and to optimize the procedure. The cool-down is driven by the helium flowing in both the outer cooling channel and in the windings connected hydraulically in parallel. We take into account limitations due to the pressure drop in the cooling circuit and the refrigerator capacity as well as heat conduction in the iron yoke. Two schemes of the hydraulic cooling circuit in the EDIPO windings are studied (coils connected in series and coils connected in parallel). The analysis is performed by means of an analytical model complemented by and numerical model. The results indicate that the cool-down to 5 K can be achieved in about 12 days.     

Solid state dye-sensitized solar cell with TiO2/NiO heterojunction: Effect of particle size and layer thickness on photovoltaic performance

The present work demonstrates the usefulness of nickel oxide as a hole transporting material in solid state dye-sensitized solar cells (SSDSSCs). We report on the photovoltaic performances of sensitized TiO₂/NiO heterojunctions, and demonstrate that the TiO₂ film thickness and morphology, as well as NiO film thickness, have significant effects on the photovoltaic behaviour of TiO₂/NiO SSDSSC. Under 1 sun AM1.5G simulated illumination, the SSDSSCs demonstrated best photovoltaic performance with a short circuit photocurrent density, open circuit voltage, fill factor and efficiency of 0.91 mA cm⁻², 780 mV, 40% and 0.3%, respectively. This study draws attention to the feasibility of enhancing the photovoltaic performance in SSDSSC devices through development of appropriately designed sensitized TiO₂/NiO heterojunctions.     

Development of a miniature cryogenic fluid circuit and a cryogenic micropump

This article presents the development of a miniaturized cryogenic fluid circuit for distributed cooling of low-temperature tracking detectors in high-energy physics (HEP). The heart of the circuit is a prototype cryogenic micropump. This volumetric pump is compatible with cooling powers of about 10-100 W, and capable of producing pressure heads of up to around 0.3 MPa. Besides detector and electronics cooling in HEP, potential applications are found in the field of superconductor technology.     

Experimental investigation on the cooling helium circulation of the internal purifier pilot plant

The internal purifier is utilized to remove impurities from impure helium, keep the helium free of any gaseous contaminants. However, there is few report on the performance improvement of the internal purifier. In this paper, we present a novel circuit of the experimental platform with GM cryocooler providing a separated cooling helium circulation as the refrigeration power supply for investigating the performance the internal purifier. Namely, that circuit is easily constructed by extracting a small stream of helium from the high-pressure side of the GM cryocooler serving as the cooling helium circulation. The experiment is then carried out to test the mass flow and the temperature of the cooling helium circulation. The impact of the modification on the cold head is also estimated. It is finally demonstrated that the circuit is sufficient to guarantee the cooling supply of the whole experimental system, which means that the modification is suitable and efficient.     

Kältemittel‐Leckschnüffler

Refrigerant leak sniffer — testing the detection limit Refrigerators, air‐conditioners, dehumidifiers, water recoolers and other cooling devices generate the coldness by circulating a refrigerating agent in a closed circuit. As refrigerants halogenated hydrocarbons are commonly used due to their good thermo‐physical properties. Unfortunately, these refrigerants are harmful to the environment since they cause a depletion of the ozone layer and thus contribute to the global warming. To avoid a loss of the refrigerant to atmosphere, the refrigeration circuit has to be tight. Law requires the leakage of a total circuit to be smaller than a few grams per year. To test the tightness of appliances and plants, mobile refrigerant detectors are commonly used. The user of a leak sniffer has to prove that his sniffer meet its specified detection limit. The present article deals with testing refrigerant sniffers according to standardized procedures.     

萤石-硫酸法生产氟化氢的新构思

根据热力学求导计算,发现萤石、硫酸混合“低温不凝固”特性,提出萤石—硫酸法生产氟化氢冷流态预反应新构思。工艺新颖、技术可行、设备简单、实施方便,可用以取代KO捏合机。     

离心式压缩机电机冷却系统设计及仿真

阐述几种离心式压缩机电机冷却方式,提出一种新型螺旋形冷却回路。对螺旋形冷却回路的损耗情况进行仿真分析,提出螺旋形冷却回路电机开设定子铁芯液态制冷剂流道的方案以降低转子带液的机械损耗。整机试验结果表明,开设定子铁芯液态制冷剂流道可以显著降低转子带液机械损耗,压缩机组能效提升约2%。