直拉单晶硅中氧沉淀的高温消融和再生长

重点研究了直拉(CZ)硅中氧沉淀在快速热处理(RTP)和常规炉退火过程中的高温消融以及再生长行为.实验发现,RTP是一种快速消融氧沉淀的有效方式,比常规炉退火消融氧沉淀更加显著.硅片经RTP消融处理后,在氧沉淀再生长退火过程中,硅中体微缺陷(BMD)的密度显著增加,BMD的平均尺寸略有增加;而经过常规炉退火消融处理后,在后续退火过程中,BMD的密度变化不大,但BMD的尺寸明显增大.氧沉淀消融处理后,后续退火的温度越高,氧沉淀的再生长越快.     

面向三维钻孔数据的体绘制

体绘制技术是计算机可视化研究和应用热点之一。以钻孔资料为源数据,结合Kriging插值构造规则网格数据模型,利用开源的Visualization Toolkit(VTK)实现了基于GPU加速的光线投射算法的钻孔数据体绘制,任意剖面显示、体切割以及体数据抠取等交互。最后,将其应用于实际工程中,验证了其合理性和实用性。     

关于电算化“甩帐率低”的解决办法

０引言现在企业中应用的财务软件不外乎两种情况：一种是商业化财务软件，另一种是结合单位实际情况开发的财务软件。二者在帐务处理上基本是按照现行财务制度要求设计的，但普遍存在“甩帐率低”的问题。究其原因主要有以下两方面：一是初始化工作不够规范，二是电算化记...     

Preparation of nano‐Ag particles and their modification on the mechanical and dielectric properties of epoxy resin

Nano‐Ag particles stabilized by a hyperbranched polymer (HBP) template were prepared for modifying the epoxy resin. The effects of preparation condition on the size and size distribution of Ag colloidal particles were studied. The Ag@HBP particles were then compounded with the epoxy resin to obtain the Ag@HBP/epoxy composites and the mechanical and dielectric properties of these composites were investigated. Dynamic mechanical analysis results show that the composites have higher loss factors than does the unmodified epoxy resin, which indicate better dissipation of mechanical energy and hence better shock or impact resistance. Fracture morphology of the composite shows a toughness feature. From the dielectric test results, the breakdown strength and dielectric constant of the composites at room temperature are increased, which can be explained by the Coulomb block effect. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Characterization of petroporphyrins in Gudao residue by ultraviolet-visible spectrophotometry and laser desorption ionization-time of flight mass spectrometry

A porphyrin-containing fraction isolated from the >500 °C residue of Chinese Gudao heavy oil was analyzed using laser desorption ionization-time of flight mass spectrometry (LDI-TOF-MS) for the first time. LDI-TOF-MS was revealed to be suitable for the characterization of petroporphyrins mixture. LDI-TOF mass analysis, combined with UV-vis measurement, indicated that the nickel porphyrins in Gudao residue are a mixture of ETIO homologues (C₂₅-C₃₄) maximizing at C₃₀ and DPEP homologues (C₂₈-C₃₇) maximizing at C₃₁. The ΣDPEP/ΣETIO ratio is about 1.04, suggesting Gudao oil is in the stage of becoming mature.     

Research on a Recognition Algorithm for Offshore-Pipeline Defects during Magnetic-Flux Inspection

Pipeline-safety evaluation is an important problem for industry. On the basis of the magnetic-flux-leakage (MFL) method, this paper presents an automated inspection device for inspection of pipeline defects, analyzes the MFL-inspection theory and some defect-feature parameters, and gives a recognizing algorithm based on a dynamic wavelet-basis-function (WBF) neural network. This dynamic network utilizes a multiscale and multiresolution orthogonal wavelet and backward-propagating through signals and has more significant advantages than BP or other neural networks used in MFL inspection. It also can control the accuracy of the predicted defect profiles, possessing high-speed convergence and good approaching features. The performance that applies the algorithm based on the network for predicting a defect profile from experimental MFL signals is also presented.__________Translated from Defektoskopiya, Vol. 41, No. 4, 2005, pp. 34–43.Original English Text Copyright © 2005 by Jin Tao, Que Peiwen, Chen Liang, Li Liang.The text was submitted by the authors in English.     

汾河二库大坝安全监测成果分析

汾河二库大坝为全断面碾压混凝土重力坝。在坝体、坝基及岸坡共埋设内、外观测测点 335个。本文就施工阶段内部观测的部分成果进行了整理分析     

毛皮类物料干燥特性模拟试验研究

采用正交试验法对不同干燥工况下毛皮物料干燥特性进行试验，给出了干燥曲线和干燥速率曲线，建立了干燥特性方程。试验方法具有通用性。通过正交分析，以干燥时间和能耗为目标给出最佳干燥工况。     

Optimization of conversion of waste rapeseed oil with high FFA to biodiesel using response surface methodology

In the present study, waste rapeseed oil with high free fatty acids (FFA) was used as feedstock for producing biodiesel. In the pretreatment step, FFA was reduced by distillation refining method. Then, biodiesel was produced by alkaline-catalyzed transesterification process, which was designed according to the 2⁴ full-factorial central composite design. The response surface methodology (RSM) was used to optimize the conditions for the maximum conversion to biodiesel and understand the significance and interaction of the factors affecting the biodiesel production. The results showed that catalyst concentration and reaction time were the limiting conditions and little variation in their value would alter the conversion. At the same time, there was a significant mutual interaction between catalyst concentration and reaction time.The biodiesel produced in the present experiment was analyzed by gas chromatography/mass spectrometry (GC/MS), which showed that it mainly contained six fatty acid methyl esters. In addition, the diesel indexes analysis showed that most of the fuel properties were in reasonable agreement with the 0# diesel standard of China (GB252-2000) and the biodiesel standard of America (ASTM D6751).