Transformation of the reabsorption characteristics of lignite treated by low and high temperature drying process

Abstract

The reabsorption characteristics of the lignite treated by low and high temperature drying process were addressed in the paper. The information about the moisture form, functional groups, effective water-filled porosities and equilibrium moisture content of the lignite before and after the drying process was investigated using Differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and a self-made reabsorption device, respectively. The results show that the low drying temperature (140, 190, 230?°C, 10?min, N₂) has little impact on the effective water-filled porosities of the resulted samples, whereas it has a great influence on the main oxygen-containing functional groups, which amount firstly decreases and then increases with the drying temperature increasing. In the case of the lignite samples dried under high-temperature (600, 700, 800?°C, 30?s, N₂), the amount of the effective water-filled porosity of the sample decreases and the amount of oxygen-containing functional groups increases as the temperature increasing. The reabsorption capability of the high temperature dried sample is much lower than that of the sample treated under low drying temperature. The reabsorption characteristics of the low-temperature dried samples are affected by the amount of the oxygen-containing functional groups, while the effective water-filled porosity is main factor for the lignite samples derived from high temperature drying process. Moreover, the work gives a good evidence that the high-temperature drying process is an effective choose for lignite upgrading.     

含氮金刚石结构中Jahn-Teller畸变效应的计算

研究了由J.Bourgoin和M.Lannoo提出的半导体内Jahn-Teller畸变效应的计算理论。应用Bourgoin和Lannoo的方法研究了含中心氮杂质金刚石结构的Jahn-Teller畸变问题,计算了34C+N簇团的T2模耦合沿%111&晶向的Jahn-Teller畸变效应,结果与实验相符。     

不同级配对微表处混和料性能的影响

微表处技术是一种性能优良的路面养护技术。首先检验了微表处用原材料的技术指标,在满足规范的要求下选择了三种不同级配,并对三种不同级配的微表处混和料的使用性能进行了比较。     

集输系统热回水管线腐蚀分析

中国石油天然气股份有限公司华北分公司第三采油厂油气集输系统热回水管线普遍存在着腐蚀问题,影响原油生产和集输的正常运行。介绍了腐蚀较严重的13个站点的水质普查、水质结垢倾向和腐蚀性情况,并在水质分析的基础上进行了热水管线腐蚀因素的试验研究,确定腐蚀主要因素为水中的溶解氧含量高,从而造成腐蚀。     

五种恒虚警方法性能分析

比较了五种恒虚警方法在各种杂波背景下的检测性能,得出CMLD-CFAR是工程上可以实现且检测性能比较好的一种恒虚警处理方法.     

从RC5到RC6

论文详细描述并分析了从RC5到RC6的演化设计过程,在详细研究了RC6性能的同时,指出了应该如何从一个旧的密码设计出好的新密码。最后对RC6和Rijndael作了一些比较,指出各自在性能上的优缺点。     

SIMPLIS环境中开关电源集成电路控制器模型的开发及应用

介绍现代开关电源行业仿真工作的意义和现状,以及专用仿真软件包SIM etrix/SIMPLIS的优点和不足。通过实例给出SIMPLIS环境中集成电路控制芯片的建模过程,并就其中的关键技术予以简单讨论。     

Automatic image hanging protocol for chest radiographs in PACS.

Chest radiography is one of the most widely used techniques in diagnostic imaging. It comprises at least one-third of all diagnostic radiographic procedures in hospitals. However, in the picture archive and communication system, images are often stored with the projection and orientation unknown or mislabeled, which causes inefficiency for radiologists' interpretation. To address this problem, an automatic hanging protocol for chest radiographs is presented. The method targets the most effective region in a chest radiograph, and extracts a set of size-, rotation-, and translation-invariant features from it. Then, a well-trained classifier is used to recognize the projection. The orientation of the radiograph is later identified by locating the neck, heart, and abdomen positions in the radiographs. Initial experiments are performed on the radiographs collected from daily routine chest exams in hospitals and show promising results. Using the presented protocol, 98.2% of all cases could be hung correctly on projection view (without protocol, 62%), and 96.1% had correct orientation (without protocol, 75%). A workflow study on the protocol also demonstrates a significant improvement in efficiency for image display.     

Thermo-Sensitive Ba0.64Sr0.36TiO3 Thin Film Capacitors for Dielectric Type Uncooled Infrared Sensors

Ba_0.64Sr_0.36TiO₃ (BST) thin films are prepared on Pt/Ti/SiO₂/Si₃N₄/SiO₂/Si substrates by a sol-gel method. Thermo-sensitive BST thin film capacitors with a Metal-Ferroelectrics-Metal (M-F(BST)-M) structure are fabricated as the active elements of dielectric type uncooled infrared sensors. XRD are employed to analyze the crystallographic structures of the films. AFM observations reveal a smooth and dense surface of the films with an average grain size of about 35 nm. Rapid temperature annealing (RTA) process is a very efficient way to improve crystallization quality. The preferable annealing temperature is 800°C for 1 min. The butterfly shaped C-V curves of the capacitors indicate the films have a ferroelectric nature. The dielectric constant and dielectric loss of the films at 100 kHz are 450 and 0.038, respectively. At 25°C, where the thermo-sensitive capacitors work, the temperature coefficient of dielectric constant (TCD) is about 5.9 %/°C. These results indicate that the capacitors with sol-gel derived BST thin films are promising to develop dielectric type uncooled infrared sensors.     

A new way for multidimensional medical data management: volume of interest (VOI)-based retrieval of medical images with visual and functional features.

The advances in digital medical imaging and storage in integrated databases are resulting in growing demands for efficient image retrieval and management. Content-based image retrieval (CBIR) refers to the retrieval of images from a database, using the visual features derived from the information in the image, and has become an attractive approach to managing large medical image archives. In conventional CBIR systems for medical images, images are often segmented into regions which are used to derive two-dimensional visual features for region-based queries. Although such approach has the advantage of including only relevant regions in the formulation of a query, medical images that are inherently multidimensional can potentially benefit from the multidimensional feature extraction which could open up new opportunities in visual feature extraction and retrieval. In this study, we present a volume of interest (VOI) based content-based retrieval of four-dimensional (three spatial and one temporal) dynamic PET images. By segmenting the images into VOIs consisting of functionally similar voxels (e.g., a tumor structure), multidimensional visual and functional features were extracted and used as region-based query features. A prototype VOI-based functional image retrieval system (VOI-FIRS) has been designed to demonstrate the proposed multidimensional feature extraction and retrieval. Experimental results show that the proposed system allows for the retrieval of related images that constitute similar visual and functional VOI features, and can find potential applications in medical data management, such as to aid in education, diagnosis, and statistical analysis.