采用真空磁控反应溅射和沸水氧化法制备Al2O3增透膜

在玻璃基片上采用金属Al靶在溅射气体Ar和反应气体O2的混合气体中,真空磁控溅射半透明的Al-Al2O3金属陶瓷薄膜,再将沉积薄膜的玻璃基片浸入沸腾的去离子水中氧化,制备成陶瓷增透膜.优化镀膜工艺和沸水氧化时间,在3.2 mm厚的低铁玻璃载片上单面沉积的增透膜的太阳透射比Te由未镀膜原片的90.4％增加到93.9％,提高了3.5％,可见光透射比Tv由91.6％增加到95.5％,提高了3.9％.双面沉积增透膜玻璃载片的Te达到96.2％,增加了5.8％,Tv达到97.2％,增加了5.6％.经过400℃高温持续40 min烘烤后膜层的光学性能基本不变.     

溅射功率对CdZnTe薄膜成分和结构的影响

采用Cd0.9Zn0.1Te晶体作为溅射靶在玻璃衬底上利用磁控溅射法制备出CdZnTe薄膜,研究了溅射功率对CdZnTe薄膜的成分、结构特性的影响。制备的CdZnTe薄膜是具有闪锌矿结构的多晶薄膜,沿（111）择优取向。随着溅射功率的增大,薄膜沉积速率增大,薄膜结晶质量提高。采用晶体靶Cd0.9Zn0.1Te溅射CdZnTe薄膜时,无论是在何种功率下CdZnTe薄膜中的Cd原子成分均高于Te原子成分,Cd原子表现为择优溅射原子。     

全玻璃SS-AlN金属陶瓷真空太阳集热管

不锈钢-氮化铝(SS-AlN)金属陶瓷太阳选择性吸收涂层于1995年在实验室制备成功,采用真空磁控溅射沉积。太阳吸收复合膜采用干涉吸收型膜层结构,由不同金属含量的两层金属陶瓷层组成吸收层。金属陶瓷吸收层采用在镀膜室中SS和Al金属靶,在溅射气体Ar和反应气体N2中同时溅射运行,SS靶非反应溅射沉积SS金属组分,Al靶反应溅射沉积AlN陶瓷组分。实验室沉积的SS-AlN吸收涂层的太阳吸收比高达94%～96%,室温辐射比3.5%～4.0%。皇明公司2001年开始产业化生产全玻璃SS-AlN真空太阳集热管。我们开发了立式集热管连续镀膜线,第一条镀膜线于2007年调试成功,投入生产。集热管镀膜线真空系统长约41 m,高约3 m。每条线日产约为1.8～2.0万支。     

直流磁控溅射制备铝薄膜的工艺研究

采用直流磁控溅射方法，以高纯Al为靶材，高纯Ar为溅射气体，在玻璃衬底上成功地制备了铝薄膜，并对铝膜的沉积速率、结构和表面形貌进行了研究。结果表明：A1膜的沉积速率随着溅射功率的增大先几乎呈线性增大而后缓慢增大；随着溅射气压的增加，沉积速率先增大，在一定气压时达到峰值后继续随气压的增大而减小。X射线衍射图谱表明Al膜结构为多晶态；用扫描电子显微镜对薄膜进行表面形貌的观察，溅射功率为2600W，溅射气压为0．4Pa时制备的Al膜较均匀致密。     

利用脉冲直流磁控溅射制备ZnO:Al薄膜的研究

利用中频脉冲直流磁控溅射法制备了平面ZnO:Al(AZO)透明导电薄膜,研究了沉积压力、衬底温度和溅射功率对AZO薄膜光电性能、薄膜稳定性的影响.结果表明:在较低沉积压力、衬底温度及溅射功率下,可获得具有低电阻率、高透过率、高稳定性的AZO薄膜.     

射频磁控溅射法制备的ZnO:Al薄膜在不同偏压下的光电特性

采用RF磁控溅射法在玻璃衬底和PET衬底上沉积了Al掺杂的ZnO(AZO)薄膜,衬底的直流偏压为0～50V.主要研究了薄膜的结构、光学和电学特性.在玻璃衬底上制备AZO薄膜的沉积速率随偏压的升高而增大,然而再增加偏压时反而下降.当偏压为30V时,在玻璃衬底上制备的薄膜的最低电阻率为6.5×10-4Ω·cm,在波长450～800nm内的平均透射率大于80%;在PET衬底上制备的薄膜也有相似的特性,但没有在玻璃衬底上制备的好.     

溅射功率对AZO透明导电薄膜的影响

采用射频磁控溅射法在玻璃衬底上沉积了AZO透明导电薄膜,并用原子力显微镜观测了薄膜表面形貌,XRD测试了薄膜相结构和单色仪测试了薄膜透射率。结果表明,制备的薄膜具有高度c轴择优取向性,其表面平整,晶粒均匀致密。当溅射功率为180W、溅射气体流量为15sccm、基片温度为200℃时制得的薄膜方阻为10Ω/□,在可见光区平均透射率大于85%。     

工艺参数对直流反应磁控溅射ZnO:Al薄膜沉积速率的影响

实验以合金靶材在玻璃衬底上运用直流反应磁控溅射法制备了ZAO(ZnO:Al)透明导电薄膜样品.研究了O2气流量,衬底温度,以及反应气压和溅射功率等工艺参数对ZAO薄膜沉积速率的影响规律.结果表明:沉积速率随O2气流量的增加显著降低,靶面溅射模式由金属模式转变为氧化物模式,而且这种转变趋势在改变其他参数时依然明显;沉积速率随溅射功率的增大几乎成线性增加,但随衬底温度的变化并不大;在反应气压增大的情况下,沉积速率不断上升,达到最大值后,又随气压的增大不断下降.     

射频磁控溅射制备Bi2Te3热电薄膜

通过射频磁控溅射，在溅射气体为Ar，气压为1Pa，溅射功率为120W时分别在聚氨酯和玻璃基底上沉积了不同厚度的Bi2Te3薄膜。Bi2Te3薄膜主要是以（221）晶面平行于基底进行外延生长，先在基底形成大量微小晶粒，合并长大成典型的纤维状组织结构。在此条件下薄膜生长速率为26nm/min，通过控制溅射时间可沉积几纳米到几微米不同厚度的薄膜。得到的p-型半导体Bi2Te3薄膜，其电阻率随薄膜厚度的增大而减小。     

直流磁控溅射有机衬底和玻璃衬底ZnO∶Al薄膜结构及特性的研究

利用直流磁控溅射法在有机薄膜衬底和普通玻璃衬底上制备出了具有良好附着性的ZnO∶Al透明导电膜,对制备薄膜的结构和光学特性进行了比较研究.研究发现:铝掺杂的氧化锌薄膜是多晶膜,具有六角纤锌矿结构;在衬底温度为100℃,溅射压强1.0 Pa,氧氩比为1∶2.58时,ZnO∶Al薄膜具有(002)择优取向,晶化也比较好,在可见光区的平均透过率分别达到了77.6%和82%.     

Partial Nucleate Pool Boiling at Low Heat Flux: Preliminary Ground Test for SOBER-SJ10

Focusing on partial nucleate pool boiling at low heat flux, SOBER-SJ10, one of 27 experiments of the program SJ-10, has been proposed to study local convection and heat transfer around an isolated growing vapor bubble during nucleate pool boiling on a well characterized flat surface in microgravity. An integrated micro heater has been developed. By using a local pulse overheating method in the experimental mode of single bubble boiling, a bubble nucleus can be excited with accurate spatial and temporal positioning on the top-side of a quartz glass substrate with a thickness of 2 mm and an effective heating area of 4.5 mm in diameter, and then grows under an approximate constant heat input provided by the main heater on the back-side of the substrate. Ten thin film micro-RTDs are used for local temperature measurements on the heating surface underneath the growing bubble. Normal pool boiling experiments can also be carried out with step-by-step increase of heating voltage. A series of ground test of the flight module of SOBER-SJ10 have been conducted. Good agreement of the measured data of single phase natural convection with the common-used empirical correlation warrants reasonable confidence in the data. It is found that the values of the incipience superheat of pool boiling at different subcooling are consistent with each others, verifying that the influence of subcooling on boiling incipience can be neglected. Pool boiling curves are also obtained, which shows great influence of subcooling on heat transfer of partial nucleate pool boiling, particularly in lower heat flux.     

Heat Transfer by Radiation through a Vapor Gap under Conditions of Film Boiling of Liquid

Theoretical models of heat transfer by radiation through a vapor gap under conditions of film boiling of liquid are treated, namely, a general wave model for a gap of arbitrary thickness and an approximate model of geometrical optics. Calculations are performed of heat transfer by radiation under conditions of film boiling of water on hot surfaces of refractory metal and molten oxide. Practical recommendations are given to calculate the distribution of the power of absorbed radiation in a water layer.     

封孔处理对ZLl08铸铝微弧氧化膜性能的影响

微弧氧化膜表面的微孔对氧化膜性能有较大的影响。采用硅酸钠、沸水和常温封孔剂对ZLl08铸铝微弧氧化膜进行了封孔处理,研究了封孔处理对微弧氧化膜性能的影响。结果表明：封孔处理后,微弧氧化膜表面形貌发生了变化,膜厚略有增加,表面硬度显著下降,耐蚀性提高。3种封孔工艺中,硅酸钠封孔后微弧氧化膜表面硬度最高,耐蚀性最好。     

Investigation of liquid-vapor interface vibrations during film boiling of Freon-113 on a spherical surface

Experimental investigation of saturated Freon-113 film boiling on a sphere with 30 mm diameter at atmospheric pressure under conditions of free convection was carried out. Nonsinusoidal wave formations at the liquid-vapor interface were revealed using high-speed video recording. The temperature gradient dependence for the average vapor film thickness was determined.     

Study of thermocapillary film rupture using a fiber optical thickness probe

Rupture of a subcooled water film flowing down an inclined plate with a 150×150 mm heater is studied using a fiber optical thickness probe. The main governing parameters of the experiment and their respective values are: Reynolds number (3.2–30.2), plate inclination angle from the horizon (3–90 deg), heat flux (0–1.53 W/cm²). The effect of the heat flux on the film flow leads to the formation of periodically flowing rivulets and thin film between them. As the heat flux grows the film thickness between rivulets gradually decreases, but, upon reaching a certain critical thickness, the film spontaneously ruptures. The critical film thickness is practically independent on the film Reynolds number as well as on the plate inclination angle and lies in the neighborhood of 60 µm (initial film thickness varies from 93 to 368 µm). The heater surface temperature prior to rupture is also independent of Re and Θ, and is about 45°C (initial film temperature is 24°C). The process of rupture involves two stages: 1) abrupt film thinning down to a very thin residual film remaining on the heater; 2) rupture and dryout of the residual film. The threshold heat flux required for film rupture is scarcely affected by the plate inclination angle but grows with the Reynolds number.     

黑果枸杞花青素智能显色膜的制备和性能研究

花青素作为植物体内存在的天然物质,不仅对人体无毒无害,还具有良好的抗氧化性能。采用溶剂提取法和超声波辅助提取法提取黑果枸杞花青素,再将花青素溶液与成膜基质共混后制备成花青素复合膜,并对复合膜进行厚度、含水率、水溶性、抗氧化性、 pH显色、红外吸收光谱等性能测定。实验测得复合膜的平均厚度为0.0387 mm,含水率为22.78%,水溶性为31.55%,水蒸气透过系数为6.2359×10-4 g·mm·Pa-1·h-1·m-2,1, 1-二苯基-2-三硝基苯肼（DPPH）抗性相当于1 mL 0.02 mol/L标准维生素E溶液的15.84倍,且在不同pH的缓冲溶液中具有良好的显色效应。实验制备得到的花青素智能显色膜具有与普通保鲜膜相似的外观和物理性质,能在水中自发降解并拥有极佳的抗DPPH自由基能力,具有良好食品包装应用前景。     

IR spectra and etch rates of plasma-enhanced chemically vapour-deposited phosphosilicate glass films

IR transmission spectra of phosphosilicate glass (PSG) films with 8 wt.% P prepared by plasma-enhanced chemical vapour deposition (PECVD) and CVD are compared. The differential IR spectrum of a PECVD PSG film differs from that of a CVD PSG film: the P=O peak has a lower intensity than the corresponding peak of the CVD film with the same phosphorus content; no peaks are evident at 980 and 500 cm⁻¹—the characteristic frequencies for P---O---P stretching and bending vibrations. The differential IR spectra of PECVD and CVD PSG films become very similar after annealing for 4 h in water vapour at 850°C. The etch rate of a PECVD film in p-etchant, which is constant throughout the film thickness, is 400 Å min⁻¹. However, the etch rate recorded after the film is subjected to annealing in water vapour at 850°C varies with the depth in the film, attaining values as high as 800 Å min⁻¹ in the region near the outer surface of the film. The results are explained as due to the oxidation of P₂O₃ to P₂O₅.     

A Study into Development of Instability and Collapse of Vapor Layer on a Heated Solid Hemispherical Surface

A study is performed into the processes of development of instability and collapse of a vapor film on a solid hemispherical surface. Optical-fiber sensors of pressure and vapor-film thickness are used in measurements; the process is videofilmed with subsequent computer processing of images. A physical model of the phenomenon is developed, which includes superheating and explosive boiling of water in recesses of wavy vapor film. The predictions are in qualitative agreement with the experimental results.     

Bubble behaviors in subcooled boiling of wetting surface under low gravity

Stainless steel plate with 30mm in length, 1 mm in width and 0.1 mm in thickness is employed for a heating surface in subcooled quasi-pool boiling of water under low gravity performed by a parabolic flight. Testing liquid subcooling is about 10K at atmospheric pressure. The wetting heating surfaces are coated with ceramics materials which have been developed by a certain glass company. DC power is applied directly into the test heating surface and the bubble behaviors are observed by a high-speed video camera. Contact angle of water droplet is about 77–96 degree for the stainless surface and 30 degree or less for the wetting surface. In the ground experiment, the size of detaching bubbles from the wetting surface is smaller than those of stainless surface and the detaching period is shorter at same heating power. The burnout heat fluxes of wetting surfaces are about 50 percent higher those of stainless surfaces. In the low gravity experiment, DC power is applied into the surface at 10 second before start of low gravity and increases slightly until burnout. A single large bubble grows on the stainless surface and finally, the surface is burned out in a short period. For wetting surface, several large coalescing bubbles appear and they move rapidly on the surface, then one of the large bubbles grows and the burnout occurs. The burnout heat fluxes are higher than those of stainless surface. The wetting ceramics surface is considered to accelerate the liquid supply and the bubble moving.     

Effect of tube diameter on boiling heat transfer and flow characteristic of refrigerant R32 in horizontal small-diameter tubes

This study investigated the effect of tube diameter on flow boiling characteristics of refrigerant R32 in horizontal small-diameter tubes with 1.0, 2.2, and 3.5 mm inner diameters. The boiling heat transfer coefficient and pressure drop were measured at 15 °C saturation temperature. The effects of mass velocity, heat flux, quality, and tube diameter were clarified. The flow pattern of R32 for adiabatic two-phase flow in a horizontal glass tube with an inner diameter of 3.5 mm at saturation temperature of 15 °C was investigated. Flow patterns such as plug, wavy, churn, and annular flows were observed. The heat transfer mechanisms of forced convection and nucleate boiling were similar to those in conventional-diameter tubes. In addition, evaporation heat transfer through a thin liquid film in the plug flow region for low quality, mass velocity, and heat flux was observed. The heat transfer coefficient increased with decreasing tube diameter under the same experimental condition. The fictional pressure drop increased with increasing mass velocity and quality and decreasing tube diameter. The experimental values of the heat transfer coefficient and frictional pressure drop were compared with the values calculated by the empirical correlations in the open literature.