Droplet Image Feedback Control System in Evaporation Experiment

In order to realize the steady-state droplet evaporation, image feedback control system is designed based on DSP. The system has three main functions: to capture and store droplet images during the experiment; to calculate droplet geometrical and physical parameters such as volume, surface area, surface tension and evaporation velocity at a high-precision level; to keep the droplet volume constant. The DSP can drive an injection controller with the PID control to inject liquid so as to keep the droplet volume constant. The evaporation velocity of droplet can be calculated by measuring the injected volume during the evaporation. The structure of hardware and software of the control system, key processing methods such as contour fitting and experimental results are described.     

Determination of Diffusion Coefficient in Droplet Evaporation Experiment Using Response Surface Method

Evaporation of a liquid droplet resting on a heated substrate is a complex free-surface advection-diffusion problem, in which the main driving force of the evaporation is the vapor concentration gradient across the droplet surface. Given the uncertainty associated with the diffusion coefficient of the vapor in the atmosphere during space evaporation experiments due to the environmental conditions, a simple and accurate determination of its value is of paramount importance for a better understanding of the evaporation process. Here we present a novel approach combining numerical simulations and experimental results to address this issue. Specifically, we construct a continuous function of output using a Kriging-based response surface method, which allows to use the numerical results as a black-box with a limited number of inputs and outputs. Relevant values of the diffusion coefficient can then be determined by solving an inverse problem which is based on accessible experimental data and the proposed response surface. In addition, on the basis of our numerical simulation results, we revisit a widely used formula for the prediction of the evaporation rate in the literature and propose a refined expression for the droplets evaporating on a heated substrate.     

Thermocapillary Convection Experiment Facility of an open Cylindrical Annuli for SJ-10 Satellite

Thermocapillary convection has always been a hot topic of great importance in either crystal growth or thin films science. A space experiment about thermocapillary convection in an open cylindrical annuli pool will be done on SJ-10 satellite. A payload for space experiment has been established, which includes a cylindrical annuli thermocapillary convection system, a thermocouple temperature controlling system and measurement system, a thermal infrared imager, a high-precision displacement sensor, and an experiment controlling system. Some experiments have been done on the ground in order to compare with the results of space experiment. Some results from the ground experiment are shown, such as temperature oscillation, surface oscillation, and flow pattern transfer.     

Space Program SJ-10 of Microgravity Research

SJ-10 program provides a mission of space microgravity experiments including both fields of microgravity science and space life science aboard the 24th recoverable satellite of China. Scientific purpose of the program is to promote the scientific research in the space microgravity environment by operating the satellite at lower earth orbit for 2 weeks. There are totally 27 experiments, including 17 ones in the field of microgravity science (microgravity fluid physics 6, microgravity combustion 3, and space materials science 8) and 10 in the field of space life science (radiation biology 3, gravitational biology 3, and space biotechnology 4). These experiments were selected from more than 200 applications. The satellite will be launched in the end of 2015 or a bit later. It is expected that many fruitful scientific results on microgravity science and space life science will be contributed by this program.     

Peculiarities of Droplet Evaporation under Radiative and Convective Heating

Technical Physics Letters - We propose a new method for determining the rate of evaporation of a lone levitating droplet under the action of radiative heat flux. Results of experimental...     

铜纳米液滴蒸发过程的分子动力学模拟

本文利用Material Studio软件成功地模拟了铜纳米液滴在真空条件下(10Pa),温度为1573~2073K的变化情况。通过研究铜液滴在蒸发过程中的均方位移(MSD),径向分布函数(RDF)及液滴直径大小的变化得出如下结论:随着模拟温度的升高,进入气相的铜原子越来越多,由于流体的各向同性,使液滴最终接近球形。当温度从1773K升温至1873K后,液滴的直径明显变小,这是因为在此温度区间体系从液相转变为气相,此时会有大量铜原子从液滴溢出进入气相,从而导致液滴变小。     

Theoretical Investigation on Rapid Evaporation of a Saline Droplet During Depressurization

This paper reports a theoretical investigation on rapid evaporation of a saline droplet during depressurization. A mathematical model was developed to simulate the droplet temperature variation by considering the ambient pressure change, the heat transfers due to evaporation and convection at the droplet surface, accompanying the heat and mass transfer inside the droplet. The component diffusion and the temperature gradient inside the droplet were mainly discussed by comparing the numerical droplet temperature with the experimental data. The result shows that, the variation of internal concentration is small, while the temperature gradient within the droplet is significant during the evaporation process. In addition, the influencing factors of the droplet temperature variation were analyzed, such as: the final ambient pressure, theinitial salt concentration and the initial droplet temperature. The present model calculations help to understand the thermodynamic process of rapid evaporation of a saline droplet during depressurization.     

Opto-electronic Bistable Devices for Image Processing

Several opto-electronic bistable devices with twisted nematic liquid crystals are designed and used for image processing. The optical bistability characteristics of liquid crystals are used for two types of light valve, those with array structure and parallel operation and those with single cell with sequential operation. Experimental studies demonstrate the application of these opto-electronic bistable devices in important operations currently used in image processors, such as intensity limiting for contrast improvement and noise elimination, contour accentuation for pattern recognition, linear and nonlinear optical filtering (in spatial and spectral domains), incoherent-to-coherent image conversion and logic operations.     

Television Techniques in Image Processing

The evolution of a single-channel video-processing system is described, together with the design and operation of a related four-channel instrument. The incorporation of this system into a video-rate interactive multispectral classifier for remote sensing imagery is discussed.     

Protein Experiment: Scientific Data Processing Platform for On-Flight Experiment Tuning

In 2009, the PROTEIN experiment was run on board of the Columbus module of the International Space Station to investigate the crystallization of proteins in microgravity using the Protein Crystallization Diagnostics Facility. This instrument was designed to allow almost real time modification of remote-operated space experiments on request by the Science Team. The complexity of the experiments and the expected high volume of raw scientific data required the development of ad-hoc analysis tools in order to provide scientist with a quick and in-depth picture of experiment progress. The integrated data analysis platform presented in this paper allowed early inspection of running experiment results and provided information for impromptu, fine-tuning experimental conditions. The feedback loop starting with remote data acquisition, followed by on ground analysis performed by the platform and finishing with experiment redesign and update, is described through several examples.     

彩色图像处理技术在等倾线图处理中的应用

目的 更精确方便地彩色光弹性耦合图像中分离等倾线。方法 将彩色图像处理技术应用于零倾线的处理中,提出了彩色图像颜色分割技术实现等倾线从耦合图像中分离的方法,并同时对等倾线进行细化、去分枝、光滑和勾画处理,获得某一角度的等倾线。结果 将该方法应用于对径受压的圆盘梯形坝体的光弹图处理,得到了较精确的结果。结论 该方法获得的实验数据能满足科学研究和工程实际的应用。     

在光电图象测量中特征信号的提取和处理（综述）

本文根据国内外有关图象测量方面的文献资料及作者个人的科研实践,就如何从图象信号中提取特征信号的各种方法及适用范围做了综述。间接二值化法是本文作者提出的新概念,它适用于炉内加热工件尺寸和浮法锡槽内玻璃带宽度及边界位置的在线测量。对各种方法的优缺点及其应用范围进行了评价。     

基于小波变换的Nanoindenter图像处理

根据纳米压痕仪的特点,对小波变换应用于纳米压痕仪图像的降噪、增强及融合方法进行了阐述。采用纳米压痕仪对单晶Al进行纳米级压痕,利用纳米定位平台原位扫描技术获得了三维图像,使用bior3.3,coif2,sym8分别对所得图像进行降噪、增强、及融合处理。结果表明,利用小波变换对纳米压痕仪图像进行处理是有效的、可行的,图像质量得到明显提高。     

Digital Image Processing Technique for Breast Cancer Detection

Breast cancer is the most common cause of death in women and the second leading cause of cancer deaths worldwide. Primary prevention in the early stages of the disease becomes complex as the causes remain almost unknown. However, some typical signatures of this disease, such as masses and microcalcifications appearing on mammograms, can be used to improve early diagnostic techniques, which is critical for women’s quality of life. X-ray mammography is the main test used for screening and early diagnosis, and its analysis and processing are the keys to improving breast cancer prognosis. As masses and benign glandular tissue typically appear with low contrast and often very blurred, several computer-aided diagnosis schemes have been developed to support radiologists and internists in their diagnosis. In this article, an approach is proposed to effectively analyze digital mammograms based on texture segmentation for the detection of early stage tumors. The proposed algorithm was tested over several images taken from the digital database for screening mammography for cancer research and diagnosis, and it was found to be absolutely suitable to distinguish masses and microcalcifications from the background tissue using morphological operators and then extract them through machine learning techniques and a clustering algorithm for intensity-based segmentation.     

数字图像处理在定量金相分析中的应用

提出通过金相图像的数字化处理对材料组织进行定量分析的方法,包括金相图像的采集,图像的分割,特征提取及在此基础上对金属与合金组织特征参数进行测量等,建立了平衡态微观组织的一种检测系统,并以实验检证此方法的可行性。