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991.
450MPa级超细组织耐大气腐蚀钢板的开发与研制   总被引:1,自引:3,他引:1  
利用变形诱导铁素体相变超细组织控制技术,通过对09CuPTiRE钢进行Nb微合金化并进行控制轧制和冷却,开发研制了晶粒尺寸为3.5~4.8pm、屈服强度达450MPa级的高强度超细组织耐大气腐蚀钢板。研究结果表明,该钢具有良好的成形、焊接和耐大气腐蚀等性能。  相似文献   
992.
A new europium (Ⅲ)complex Eu(HFNH)3Phen (HFNH: 4, 4, 5, 5, 6, 6, 6-heptafluoro-l-(2-naphthyl)hexane-1,3-dione ; phen : 1, 10-phenanthroline) was synthesized and its tribolumineseent phenomenon was observed. Photoluminescence and tfiboluminescence spectra were successfidly determined. The most intense tfiboluminescent emission originates from the transition of the central Eu^3 ion from ^5D0 level to ^7F2 level. The tribolunlinescent spectrum is basically similar to that of photoluminescence, which correlates with the disorders of F atoms.  相似文献   
993.
Large Magnetic Entropy Effect in La2/3Ca1/3MnO3   总被引:2,自引:0,他引:2  
The magnetocaloric effect in the colossal magnetoresistance material La2/3Ca1/3MnO3 was studied. From the measurements of temperature dependence of magnetization in various magnetic fields, the large magnetic entropy change associated with the ferromagnetic-paramagnetie transition was discovered. This result suggests that perovskite manganites are suitable candidates as working substance in magnetie refrigeration technology.  相似文献   
994.
普通加速度计只能输出单向加速度信号,速度和位移量需要经过后续软件进行积分处理得到。设计了一种用于飞行器的智能传感器,可以同时以数字量和模拟量两种形式输出加速度、速度和位移,并可接收外部的复位和启动信号。智能传感器体积小、准确度高,试验中,取得了满意效果。  相似文献   
995.
本文介绍了新一代的可编程自动化控制器(PACs)的概念、产生背景及现状,分析了其构成方式、技术优势,最后阐述了其应用前景及发展趋势。  相似文献   
996.
Electropulse modification (EPM) process, a new physical field method for improving the solidification structure of metals was introduced.Different from other research, EPM is only acting pulse current on melt under liquid state.The solidification structure of Al-Si alloys, A1-Cu alloys,cast iron and steel can be modified obviously with this method: the solidification structure of ZL101 alloy presented the Na and Sr modification and the mechanical properties were enhanced; a large number of primary silicon appeared in the microstructure of ZL109 alloy; the equiaxed grain zone was expanded and the grains were fined in Al-5.0wt% Cu alloy; the graphitization took place in solidification process of molten cast iron; the grain sizes of solidification structure of T8 steel were reduced significantly and the shape of steel pearlites also changed; the equiaxed grain zone increased to 88% from original untreated 19%, the equiaxed grains were fined and the intercrystalline crack was avoided in concasting billet by continuously treating liquid electrical sheet steel in tundish.Effects of rare earths on casting Al-Si alloys were also summarized.The method of modifying the solidification structure of rare earth Al-Si alloys with EPM in producing the alloys was proposed.  相似文献   
997.
A comparison of the performance of three feature extraction methods was made for mapping forest crown closure (CC) and leaf area index (LAI) with EO-1 Hyperion data. The methods are band selection (SB), principal component analysis (PCA) and wavelet transform (WT). Hyperion data were acquired on October 9, 2001. A total of 38 field measurements of CC and LAI were collected on August 10-11, 2001, at Blodgett Forest Research Station, University of California at Berkeley, USA. The analysis method consists of (1) conducting atmospheric correction with High Accuracy Atmospheric Correction for Hyperspectral Data (HATCH) to retrieve surface reflectance, (2) extracting features with the three methods: SB, PCA and WT, (3) establishing multivariate regression prediction models, (4) predicting and mapping pixel-based CC and LAI values, and (5) validating the CC and LAI mapped results with photo-interpreted CC and LAI values. The experimental results indicate that the energy features extracted by the WT method are the most effective for mapping forest CC and LAI (mapped accuracy (MA) for CC=84.90%, LAI MA=75.39%), followed by the PCA method (CC MA=77.42%, LAI MA=52.36%). The SB method performed the worst (CC MA=57.77%, LAI MA=50.87%).  相似文献   
998.
Extensive research has been performed for developing knowledge based intelligent monitoring systems for improving the reliability of manufacturing processes. Due to the high expense of obtaining knowledge from human experts, it is expected to develop new techniques to obtain the knowledge automatically from the collected data using data mining techniques. Inductive learning has become one of the widely used data mining methods for generating decision rules from data. In order to deal with the noise or uncertainties existing in the data collected in industrial processes and systems, this paper presents a new method using fuzzy logic techniques to improve the performance of the classical inductive learning approach. The proposed approach, in contrast to classical inductive learning method using hard cut point to discretize the continuous-valued attributes, uses soft discretization to enable the systems have less sensitivity to the uncertainties and noise. The effectiveness of the proposed approach has been illustrated in an application of monitoring the machining conditions in uncertain environment. Experimental results show that this new fuzzy inductive learning method gives improved accuracy compared with using classical inductive learning techniques.  相似文献   
999.
电喷雾串联质谱法分析阿托品在大   总被引:1,自引:0,他引:1  
陈怀侠  杜鹏  韩凤梅  陈勇 《质谱学报》2007,28(3):169-173
用液相色谱-电喷雾离子阱串联质谱(LC-ESIIT-MSn)联用法研究阿托品在大鼠肠内菌中的代谢,以阿托品优化色谱及质谱条件,总结其色谱及质谱行为规律。将阿托品与大鼠肠内菌体外厌氧温孵培养,与空白样品及阿托品标准品相比较,根据被测物的多级质谱数据,鉴定代谢物并阐述其结构。在温孵液中发现了阿托品的脱水及水解代谢产物,即脱水阿托品、托品和托品酸。该方法灵敏、快速、简单,适合于药物代谢分析。  相似文献   
1000.
A geometric constraint solver for 3-D assembly modeling   总被引:2,自引:0,他引:2  
In this paper, we propose a geometric constraint solver for 3-D assembly applications. First, we give a new geometry and constraint expression based on Euler parameters, which can avoid singular points during the solving process and simplify constraint types. Then we present a directed graph based constructive method to geometric constraint system solving that can handle well-, over- and under-constrained systems efficiently. The basic idea of this method is that it first simplifies the constraint graph by pruning those vertices which have only in-arcs from the graph and then reduces the size of strongly connected components (SCCs) left in the graph by DOF-based analysis. The method can solve all kinds of configurations including closed-loops. After that, we apply a hybrid numerical method of Newton–Raphson and Homotopy to solve under-constrained systems. The hybrid method makes use of the high efficiency of the Newton–Raphson method as well as the outstanding convergence of the Homotopy method. Finally, we give a practical example and conclusion.  相似文献   
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