Study of structural,electrical and optical properties of vanadium oxide condensed films deposited by spray pyrolysis technique

Vanadium oxides condensed films are prepared on glass substrates, using spray pyrolysis （SP） technique. The effects of substrate temperature, vanadium concentra- tion in initial solution and the solution spray rate on the nano-structural, electrical, and optical properties of depos- ited films were investigated. Characterizations of the sam- ples were performed using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and UV-Vis spec- troscopy methods. The type and concentration of the charge carriers were determined and measured by Hall effect experiment. XRD patterns showed that the prepared films had polycrystalline structure, mostly tetragonal fl-V205 and V409 phases with the preferred orientation along （200） direction. The Hall effect experiment revealed that all samples were n-type, except the ones deposited at substrate temperatures Tsub ： 300 ~C and Tsub = 450 ~C, vanadium concentration 0.1 mol/L and solution spray rate 10 mL/min. The charge carrier concentrations obtained were in the range 1016-1018 cm-3. The lowest sheet resistance （R~） was obtained for the samples prepared at T~ub = 450 ~C, vana- dium concentration 0.05 mol/L and solution spray rate 10 mL/min. It was also found that the optical transparency of the samples changed from 20% to 75% and the optical bandgap of the samples was from 2.22 eV to 2.58 eV, depending on the deposition conditions.     

高精度半导体激光器温度控制系统技术研究

本文给出了一种利用高信噪比的运算放大器与半导体制冷器设计的激光光源电路驱动系统,以及半导体激光器的稳定度实验测量结果。实验证明,本驱动系统能为半导体激光器提供高稳定度的恒温控制(ATC),温度控制精度可达0.01℃,波长控制精度可达0.1nm,而且提高了半导体激光器的使用寿命和输出波长的单一性。     

Semi-analytical Monte Carlo simulation of laser-induced fluorescence propagation in an optically participating spray

A semi-analytical Monte Carlo (SMC) simulation was developed to simulate the propagation of laser-induced fluo- rescence (LIF) in an optically participating spray, which simultaneously exhibits spectrally dependent emission, anisotropic scattering, absorption, and re-emission. The SMC simulation is described and then applied to an experimental configuration of a cloud of polydisperse droplets composed of water and sulforhodamine B dye. In the SMC simulation, the collected LIF flux on the remote receptor element is calculated as the global contribution from the emissive source, single, twice, … and nth collision events in any sequence. The effects on the fluorescence photons propagation of spray parameters like the dye concentration, droplets concentration, and droplets size are examined. Three spectral bands representing different optical properties are chosen to analyze the interference of absorption, scattering and re-emission on the detected LIF flux. The obtained spectral LIF flux distribution on the receptor demonstrates a “red shift” phenomenon.     

喷雾热解法制备SnO2薄膜的结构及性能研究

采用喷雾热解法,在玻璃基板上制备了辐射率较低的SnO2薄膜。利用紫外可见光分光光度计、XRD等手段,研究了沉积温度、液流量对薄膜结构及光电性能的影响。结果表明,沉积温度为520℃、液流量为1.30mL/s时,薄膜具有较佳的电学、光学性能,透过率为80%,电阻率为7×10-4Ω.cm。     

基于PID控制算法的空调服温控系统设计

文中提出空服装的概念,以单片机为核心、半导体制冷器TEC1-12605为执行部件的温度调节系统,通过数字温湿度传感器DHT60采集温度和湿度,数码管显示衣服内当前的温度和湿度.空调服穿着方便、舒适、美观、安全,能够满足不同季节个人温度环境的需要.     

喷淋冷却器腐蚀原因分析及改进措施

V-605喷淋冷却器出现局部腐蚀的问题。设备发生多次的腐蚀泄漏,造成了该装置的多次停工。本文分析设备的腐蚀原因及其形成机理,通过更换设备材质,并提出相应的防腐技术措施,使设备的腐蚀问题得到改善,生产装置能长周期稳定运行。     

Resuspension of wall deposits in spray dryers

Wall deposition occurs in spray dryers when dried or partially dried particles contact and adhere to the walls during operation, thus reducing the yield of product collected. Wall deposits also present a product contamination risk and a fire or explosion risk when spray drying products that oxidize exothermically, such as milk powder. Re-entrainment is the resuspension of spray dryer wall deposits into the main gas stream for collection as product. Literature suggests that the process for re-entrainment of particles from spray dryer wall deposits is strongly dependent on particle size and gas velocity.     

Multidimensional modeling of Dimethyl Ether （DME） spray combustion in DI diesel engine

INTRODUCTION The use of dimethyl ether (DME) as an alterna-tive fuel appears to be a promising approach for si-multaneously minimizing NOx and soot emissionfrom conventional diesel engines. The lowself-ignition temperature of 508 K and the high oxy-gen content of 34.8 percent (mass fraction) are twomajor factors characterizing low soot and unburnedtotal hydrocarbon (THC) emissions. Since the firstintroduction of the concept by Sorenson and Mik-kelsen (19…     

Prediction of wall deposition behaviour in a pilot-scale spray dryer using deposition correlations for pipe flows

INTRODUCTION Abbott (1990) reported that wall deposition inspray dryers may pose a potential fire risk and com-promise hygiene requirements, and reduce productquality and yield. Spray dryer hazards include igni-tion of explosible dust clouds, dust deposits, bulkpowder deposits and flammable vapour. Kieviet(1997) noted that wall deposition affected the resi-dence time distribution of particles, and particularlythat an important factor in determining residencetimes with high wall deposition…     

电晕放电与电晕荷电水雾表面灭菌的初步研究

本研究了电晕放电表面灭菌及电晕荷电水雾表面灭菌，得到了在室温条件下酵母菌存活率与灭菌时间的关系，分析了两种情况下的灭菌机理。