Low-temperature conformal vacuum deposition of OLED devices using close-space sublimation

Close-space sublimation(CSS)has been demonstrated as an alternative vacuum deposition technique for fabricating organic light-emitting diodes(OLEDs).CSS utilizes a planar donor plate pre-coated with organic thin films as an area source to rapidly transfer the donor film to a device substrate at temperatures below 200℃.CSS is also conformal and capable of depositing on odd-shaped substrates using flexible donor media.The evaporation behaviors of organic donor films under CSS were fully characterized using model OLED materials and CSS-deposited films exhibited comparable device performances in an OLED stack to films deposited by conventional point sources.The low temperature and conformal nature of CSS,along with its high material utilization and short process time,make it a promising method for fabricating flexible OLED displays.

Numerical simulation of temperature distribution and heat transfer during solidification of titanium alloy ingots in vacuum arc remelting process

In order to get a better understanding of the vacuum consumable arc remelting(VAR) processes and thus to optimize them,a 3D finite element model was developed for the temperature fields and heat transfer of titanium alloy ingots during VAR process.The results show that the temperature fields obtained by the simulation are well validated through the experiment results.The temperature distribution is different during the whole VAR process and the steady-state molten pool forms at 329 s for d100 mm × 180 mm ingots.At the initial stage of remelting,the heat dissipation of crucible bottom plays an important role in the whole heat dissipation system.At the middle of remelting,the crucible wall becomes a major heat dissipation way.The effect of cooling velocity on the solidification structure of ingots was investigated based on the temperature fields and the results can well explain the macrostructure of titanium alloy ingots.

Temperature Simulation of Berry Slices Under Microwave Vacuum Puffing Conditions

In order to study the temperature simulation of berry slices in microwave vacuum puffing process, numerical simulation method was used to simulate the temperature in different time according to theoretical calculation result and the deviation had been verificated throughout the experiment. The better uniform of temperature between experiment and simulation could be concluded except in the period of rapid temperature increase. The temperature reached the high point of 130.25℃ in the middle point of slices at 100 s, while the temperature was over 50℃ in external parts of slices for the reason of thermal diffusion. Conclusions could be drawn that the model was effective and numerical analysis could simulate the temperature simulation for berry leather in microwave vacuum puffing process.

Effect of temperature on vacuum hot bulge forming of BT20 titanium alloy cylindrical workpiece

Temperature is one of the key parameters for BT20 titanium alloy cylindrical workpiece manufactured by vacuum hot bulge forming. A two-dimensional nonlinear thermo-mechanical coupled FE model was established. Numerical simulation of vacuum hot bulge forming process of titanium alloy cylindrical workpiece was carried out using FE analysis software MSC Marc. The effects of temperature on vacuum hot bulge forming of BT20 titanium alloy cylindrical workpiece were analyzed by numerical simulation. The simulated results show that the Y-direction displacement and the equivalent plastic strain of the workpiece increase with increasing bulge temperature. The residual stress decreases with increasing bulge temperature. The optimal temperature range of BT20 titanium alloy during vacuum hot bulge forming is 750-850 ℃. The corresponding experiments were carried out. The simulated results agreed well with the experimental results.

Vacuum electron beam brazing technology and finite element analysis on temperature field of capillary to plate joint

Some parts with capillary to plate joint have important application in aerocrafi. Vacuum electron beam brazing （VEBB） technology is used to realize this jointing with capillaries. Firstly 3D finite element analysis model is built in this paper according to this special structure. And then ANSYS finite element analysis software is used to analyze brazing temperature field at different brazing parameters. The calculation results show that the temperature field of simulation has good agreement with that measured by experiment, which proves dependence of the model built in this paper. And also reference parameters could be provided for real brazing process through calculation in this model. Brazed joint of capiUary to plate with good performance is achieved using VEBB technology. The achievement of the study will be applied in aerocrafi in the future.

Aluminium-based moderate temperature filler metals for vacuum brazing of 6061 aluminium alloy

Four kinds of aluminum based moderate temperature filler metals used for vacuum brazing of 6061 aluminum alloy were prepared by rapid solidification-isothermal rolling.The effects of alloy elements content on the melting characteristics of filler metals was studied by Differential Scanning Calorimetry(DSC).The microstructures of the filler metals and brazed joints were observed by scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS).The results show that with the increase of Cu content into the filler metals,the liquid phase temperature gradually is decreased.Microstructure characterzation of the brazed joints shows the eutectic structure of(α+β)and(α+θ)decrease gradually,θ-CuAl_(2)(Ni)gradually increases and transforms from small fishbone shapes to block shapes.Peak shear strength of 83 MPa for the 6061 aluminum joint with Al-9.5Si-10Cu-2Ni-0.5Mg was achieved after brazing at 575℃for 2 min.

A Realistic Interpretation of Quantum Wavefunctions as Temperature Dependent Vacuum Polarization Waves

We discuss in this paper a novel interpretation of Born rule as an approximated thermodynamic law which emerges from the interaction of a quantum system with a non-stationary thermal bath associated to vacuum fluctuations induced by external environment radiation. In particular we assume that vacuum polarization is a real non relativistic phenomena caused by hidden vacuum charge oscillations which diffuses heat energy in a dispersive and dissipative dielectric medium with a temperature dependent speed of propagation. We propose a model which couples vacuum wavefunctions to vacuum charge fluctuations and we deduce a temperature dependent running fine structure constant function proportional, at first approximation, to the squared of the effective electron charge and compatible with known experimental data. We interpret the vacuum symmetry breaking energy fluctuations induced in scattering experiments of particle physics and in laser assisted nuclear reactions as thermal quasi-monochromatic beams produced by the decay of hidden non equilibrium massive photons propagating with a variable light speed. We suggest, exploiting an old analogy between plasmons and pseudo Goldstone bosons, to interpret heat diffusion of this non relativistic polarized vacuum as a real De Broglie electromagnetic scalar wave associated to the radiation emitted by the hidden massive photons with acceleration proportional to vacuum Unruh like temperature. We predict a temperature dependent deviation from Coulomb law and a generalized dispersive law of these hidden unstable photons that could be revealed as not stationary coloured noise in experiments on anomalous heat diffusions associated to the decay of unstable accelerated pairs produced in nuclear physics experiments. We discuss then how our proposal of a temperature dependent non relativistic vacuum polarization might be applied to deduce a dynamic generalization of Born rule based on a realistic interpretation of quantum wavefunctions as averaged electromagnetic waves of hidden massive photons. Finally we suggest to test our time asymmetric model looking for very fast oscillating polarization thermal waves emitted during the not instantaneous wavefunction collapse and revealed as not stationary bulk heating effects in experiments on accelerated conductors and nanoconductors.

Exploring the Low-Temperature Oxidation Chemistry of Cyclohexane in a Jet-Stirred Reactor:an Experimental and Kinetic Modeling Study

We report the investigation on the low-temperature oxidation of cyclohexane in a jet-stirred reactor over 500-742 K. Synchrotron vacuum ultraviolet photoionization mass spectrometry （SVUV-PIMS） was used for identifying and quantifying the oxidation species. Major products, cyclic olefins, and oxygenated products including reactive hydroperoxides and high oxygen compounds were detected. Compared with n-alkanes, a narrow low-temperature window （-80 K） was observed in the low-temperature oxidation of cyclohexane. Besides, a kinetic model for cyclohexane oxidation was developed based on the CNRS model [Combust. Flame 160, 2319 （2013）], which can better capture the experimental results than previous models. Based on the modeling analysis, the 1,5-H shift dominates the crucial isomerization steps of the first and second O2 addition products in the low-temperature chain branching process of cyclohexane. The negative temperature coefficient behavior of cyclohexane oxidation results from the reduced chain branching due to the competition from chain inhibition and propagation reactions, i.e. the reaction between cyclohexyl radical and O2 and the de- composition of cyclohexylperoxy radical, both producing cyclohexene and HO2 radical, as well as the decomposition of cyclohexylhydroperoxy radical producing hex-5-en-l-al and OH radical.

Low Temperature Luminescence Properties of Tm^(3+) Doped Aluminate Phosphor

(Ba0.66Sr0.33)Mg0.8Al11.47O19:Tm0.013+(BSMA:Tm3+ ) phosphor was synthesized by solid-state reactions. The sample was characterized by X-ray diffraction (XRD), scanning electronic microscope (SEM), vacuum ultraviolet (VUV) spectra, ultraviolet (UV) spectra and FT-IR spectrum. XRD pattern reveals that BSMA: Tm3 + has the same structure as BaAl12O19 phase. SEM image illustrates that the phosphor has the hexagonal shape and deep slice structure. VUV and UV emission spectra at 20, 50 and 100 K show that the low temperature luminescence intensities become weak gradually with the increasing of the temperature under 147 and 254 nm excitation. The strong broadband peaks at around 357 and 397 nm and the peak at 516 nm under 147 nm excitation all correspond to the characteristic transitions of Tm3 + ions. However, under UV (254 nm) excitation, the main peak becomes 530 nm which has very high line intensity, and the peaks at about 362 and 403 nm are very weak. The excitation spectrum at 20 K shows that there are three absorption peaks at around 153, 186 and 193 nm when 516 nm emission is monitored. The absorption peaks of [AlO4], [AlO6] and Al-0 can be observed in FT-IR spectrum.

Light Hadrons at Finite Temperature in the Linear Sigma Model

The vacuum properties at finite temperature for the linear sigma model are studied by using the effective potential formalism.It is found that the light hadronic masses drop fast with increasing temperature.An extensive scaling behavior of light hadronic masses is observed and is found to follow the scaling law postulated in dense matter.

Plasma diagnosis of tetrahedral amorphous carbon films by filtered cathodic vacuum arc deposition

Filtered cathodic vacuum arc(FCVA)deposition is regarded as an important technique for the synthesis of tetrahedral amorphous carbon(ta-C)films due to its high ionization rate,high deposition rate and effective filtration of macroparticles.Probing the plasma characteristics of arc discharge contributes to understanding the deposition mechanism of ta-C films on a microscopic level.This work focuses on the plasma diagnosis of an FCVA discharge using a Langmuir dualprobe system with a discrete Fourier transform smoothing method.During the ta-C film deposition,the arc current of graphite cathodes and deposition pressure vary from 30 to 90 A and from 0.3 to 0.9 Pa,respectively.The plasma density increases with arc current but decreases with pressure.The carbon plasma density generated by the arc discharge is around the order of10^(10)cm^(-3).The electron temperature varies in the range of 2-3.5 eV.As the number of cathodic arc sources and the current of the focused magnetic coil increase,the plasma density increases.The ratio of the intensity of the D-Raman peak and G-Raman peak(I_(D)/I_(G))of the ta-C films increases with increasing plasma density,resulting in a decrease in film hardness.It is indicated that the mechanical properties of ta-C films depend not only on the ion energy but also on the carbon plasma density.

Vacuum Correlations, Detector Efficiency Fluctuations and Classical Dynamic Violations of CH-Inequality

We study in this paper the possible influence of vacuum fluctuations on photo detection and its background noise in Bell tests. We analyze its consequences on the standard statistical analysis of data showing that it is not fulfilled anymore the conventional hypothesis of a Poisson like probability density distribution of single photodetection events. We assume that vacuum fluctuations are due to real and measurable fluctuating fields, as recently confirmed experimentally, and that their non null correlations outside the light cone contribute to photon coincidence rates making them time dependent. We introduce a generalized Bell like correlation function which contains a new term due to supposed vacuum induced photon counting events. We deduce then a generalization of CH-inequality which takes in account the effect of these vacuum electric fields on detector efficiency. We predict an apparatus temperature fluctuations during photon detection which we suggest could be observed by looking for colored noise thermal emission of the photodetectors, generalizing the standard white noise prediction of C.S.L. models on wave function collapse postulate. We discuss an experimental test of this prediction, based on the idea of inducing a thermal wave on the whole quantum detectors, aimed to observe time dependent deviations from standard stationary statistical predictions of Quantum Mechanics.

低温真空油炸柿子脆片工艺优化及其品质分析

本文以柿子为原料,开展油炸温度、油炸时间、脱油时间以及切片厚度4个单因素对低温真空油炸柿子品质影响,并根据Box-Behnken试验原理,以柿子脆片的脆度、色差为响应值对低温真空油炸柿子脆片加工工艺进行优化,进一步对最终产品理化成分、微生物指标和微观结构进行分析。结果表明,油炸温度、油炸时间、脱油时间和切片厚度都影响柿子脆片的脆度和色差,经响应面优化试验分析并根据实际修正确定低温真空油炸柿子脆片的最佳工艺为:脱油时间5 min、油炸时间50 min、油炸温度80℃、切片厚度5.5 mm。该条件下柿子脆片脆度858.97 g、色差值ΔE 17.28、水分含量2.60%、含油率为22.53%、可滴定酸0.34 g/L、V_(C)含量31.20 mg/100 g;柿子脆片产品色泽金黄、形状完整,脆片内部呈现蜂窝状多孔疏松结构,产品口感酥脆,微生物指标符合卫生要求。本研究可为柿子低温真空油炸脆片产品的开发提供技术支撑。

Analysis of Temperature and Concentration Polarizations to Improve the Performance of Vacuum Membrane Distillation

Vacuum membrane distillation technology shows considerable promise for the treatment of mine water. Nevertheless, the current vacuum membrane distillation technology’s significant reliance on a heat source presents a challenging equilibrium between its energy consumption and thermal efficiency. Consequently, the present study employed computational fluid dynamics (CFD) calculations and analyses to examine the phenomena of temperature-differential polarisation and concentration-differential polarisation generated during the membrane distillation process, and to ascertain the extent to which the operating parameters affect them. Furthermore, it was observed that CPC and TPC exhibited a notable decline with the elevation of feed inlet temperature, while the polarisation phenomenon was diminished with the augmentation of feed inlet flow rate. The optimal equilibrium between membrane flux and thermal efficiency is intimately associated with the operating parameters. Additionally, this study offers a theoretical rationale for the enhancement of vacuum membrane distillation performance.

真空冷冻干燥升华温度对玉米种子品质的影响

本文采用真空冷冻干燥机对玉米种子进行冷冻干燥处理,研究不同升华温度(3℃、5℃、7℃、9℃)条件下其物性指标(含水率、容重、出碴率、颗粒度指数、裂纹率、最大力、最大力点变形)和活性指标(发芽率、呼吸强度、相对导电率)的变化规律。研究结果表明:玉米种子的含水率、容重、出碴率、最大力、最大力点变形随升华温度升高先降低后升高,颗粒度指数随升华温度升高先增大后减小,裂纹率、相对电导率随升华温度升高先升高后降低。不同升华温度的玉米种子活性都有所下降,发芽率也都有所下降。在升华温度5℃下玉米种子呼吸强度最小,最适宜储存。

肉桂精油处理结合真空包装对冷鲜牛肉的保鲜作用

为探究肉桂精油对冷鲜牛肉的保鲜效果,用不同浓度的肉桂精油溶液浸泡牛肉并真空包装后于4℃下贮藏20 d,以菌落总数、挥发性盐基氮值、硫代巴比妥酸值、pH值以及感官评分为指标,测定肉桂精油对冷鲜牛肉的保鲜效果,同时考察牛肉中肉桂醛含量变化和精油对牛肉适口性的影响。结果表明,肉桂精油处理结合真空包装对冷鲜牛肉有显著保鲜作用,且浓度越大保鲜效果越好,1.2%肉桂精油处理后的牛肉在第20天各项指标仍在标准范围内。牛肉的菌落总数、挥发性盐基氮值和pH值的增长速度均得到控制,脂质过氧化程度得到延缓。肉桂醛含量对冷鲜牛肉适口性影响结果表明,经过1.2%肉桂精油保鲜的牛肉中,肉桂醛含量仅为0.09 mL/kg,并不影响牛肉的口感。因此,肉桂精油结合真空包装对鲜牛肉具有很好的保鲜效果,且不会影响牛肉的适口性。

真空纳米二极管和三极管综述

真空纳米二极管和真空纳米三极管具有与传统真空管相似的基本功能,但却可以通过现有先进的微加工工艺线制造,以实现尺寸小、重量轻和高度集成,这使得它们在最近十年发展迅速。综述了真空纳米二极管和三极管的起源、发展历史和最新技术状态。介绍了典型的横向结构、垂直结构和环栅结构器件,并分析了各自优缺点。硅基器件对于成熟微加工工艺兼容性最好,但基于金属和一些宽带隙半导体材料,如碳化硅和氮化镓的真空纳米器件显示更好的电性能、耐温性和耐辐射性。尽管当今最发达的真空纳米二极管和三极管在大多数常规应用中仍然无法和固态集成电路抗衡,但它们正得到更多关注,并有望首先在高温或强辐射等恶劣环境实现应用。

低温温差条件下不同尺寸比例钢化真空玻璃变形特征研究

钢化真空玻璃导热差且具有冷收缩性能,当两侧玻璃温度差异较明显时,在冷收缩作用下,导致钢化真空玻璃弯曲变形,甚至出现真空环境失效,这极大限制了钢化真空玻璃在寒带地区的推广应用。基于此,进行了低温温差下钢化真空玻璃的变形测试和数值模拟,分析了低温温差和不同尺寸比例下,钢化真空玻璃两侧玻璃之间的协同变形规律。结果表明:试验与数值模拟结果相对误差在2%以内,钢化真空玻璃热-力学耦合模型具有可靠性;低温条件下玻璃整体向上弯曲变形,中心点向内凹陷,变形与温差呈正比关系;同一温差下,钢化真空玻璃长边长度相同时,随着长宽比的减小,长边上的最大变形量会增大。能够为钢化真空玻璃在极寒地区的推广应用及生产工艺的改进提供理论依据。

大电流真空电弧开断过程瞬态特性仿真分析

针对开断过程中传统稳态模型无法表征真空电弧动态特性问题,以工频电流下开断峰值为10 kA大电流真空电弧为研究对象,搭建等离子体弧柱区二维物理模型,在已有双温磁流体动力学稳态模型中引入密度、温度、压力及速度等流场参数时变项,同时利用动网格技术控制弧柱区变化速率,模拟触头分闸过程,综合考虑电流及开距变化情况下等离子体各物理场参数变化,以获取开断时电弧微观流场瞬态特性,探究开断过程中电弧形态及能量变化。分析结果可知:离子压力、温度、电子温度和阳极表面能流密度均随动、静触头分离而减小;离子速度无明显变化;等离子体不断向外扩散,由于电流减小,金属蒸汽源也逐渐减少,极间等离子体密度降低,阳极尚未达到活跃程度,最终电弧熄灭。

基于响应面法的枸杞低温真空干燥工艺优化

为了提升枸杞的干燥品质,减少它的营养物质流失和色泽褐变等问题,采用低温真空干燥技术加工枸杞,研究了不同干燥温度、真空度、热水流速对枸杞干燥品质及特性的影响。在前期单因素的基础上,以枸杞的平均干燥速率、干燥不均匀度、色差、复水率4个指标进行响应面分析,建立了枸杞低温真空干燥的二次多项式回归模型。试验结果表明,各因素对枸杞干燥品质综合评分的影响从大到小为:干燥温度、真空度、热水流速;枸杞的最佳工艺参数为干燥温度67℃、真空度0.086 MPa、热水流速2.2 m/s,综合评分值为0.713,与预测结果偏差仅为1.5%。低温真空干燥提高了枸杞的品质与特性,为枸杞低温真空干燥技术的应用提供参考。