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立式钢制圆柱储罐的动提离控制 被引量:4
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作者 孙建刚 周丽 +1 位作者 袁朝庆 郝进锋 《大庆石油学院学报》 CAS 北大核心 2001年第3期102-105,共4页
针对浮放立式储罐地震响应及提离效应 ,考虑基础与土壤的相互作用 ,研究了减小地震响应、降低提离的控制方法 ,建立了控制体系的力学分析模型 ,并给出了运动分析方程 .对实际应用的系列浮顶罐进行了数值仿真计算 ,探讨了控制体系基频和... 针对浮放立式储罐地震响应及提离效应 ,考虑基础与土壤的相互作用 ,研究了减小地震响应、降低提离的控制方法 ,建立了控制体系的力学分析模型 ,并给出了运动分析方程 .对实际应用的系列浮顶罐进行了数值仿真计算 ,探讨了控制体系基频和阻尼比对减震效果的影响 ,附加减震装置刚度的最佳基频段为 0 .5~ 3 .0rad/s ,阻尼比宜取 0 .1~ 0 . 展开更多
关键词 钢制圆柱储罐 油罐 地震响应 立式储罐 离控制
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MOVING OBJECT TRACKING IN DYNAMIC IMAGE SEQUENCE BASED ON ESTIMATION OF MOTION VECTORS OF FEATURE POINTS 被引量:2
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作者 黎宁 周建江 张星星 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2009年第4期295-300,共6页
An improved estimation of motion vectors of feature points is proposed for tracking moving objects of dynamic image sequence. Feature points are firstly extracted by the improved minimum intensity change (MIC) algor... An improved estimation of motion vectors of feature points is proposed for tracking moving objects of dynamic image sequence. Feature points are firstly extracted by the improved minimum intensity change (MIC) algorithm. The matching points of these feature points are then determined by adaptive rood pattern searching. Based on the random sample consensus (RANSAC) method, the background motion is finally compensated by the parameters of an affine transform of the background motion. With reasonable morphological filtering, the moving objects are completely extracted from the background, and then tracked accurately. Experimental results show that the improved method is successful on the motion background compensation and offers great promise in tracking moving objects of the dynamic image sequence. 展开更多
关键词 motion compensation motion estimation feature extraction moving object tracking dynamic image sequence
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变装药高效抽气装置设计与实验研究 被引量:3
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作者 李进 于存贵 闫文兵 《火炮发射与控制学报》 北大核心 1998年第1期40-44,39,共6页
介绍了高效抽气装置是在传统结构的基础上改进的单向进气活门,并特地在贮气筒一端安装排气控制阀。用提动阀的自动升降来控制有效排气时间,实验证明这种设计是成功的。
关键词 抽气装置 单向进气活门 排气控制阀 提动
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A modified one-step procedure for rapid RNA isolation from insect 被引量:4
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作者 景天忠 王志英 +1 位作者 刘宽余 齐凤慧 《Journal of Forestry Research》 SCIE CAS CSCD 2006年第2期129-131,共3页
A modified guanidinium isothiocyanate method was used to extract total RNA from two forest insect species Clostera anastomosis and Saperda populnea. The integrity of RNA was demonstrated by the methods of gel electrop... A modified guanidinium isothiocyanate method was used to extract total RNA from two forest insect species Clostera anastomosis and Saperda populnea. The integrity of RNA was demonstrated by the methods of gel electrophoresis and cDNA analysis. Typical A260/ A280 absorbance ratio of the total RNA was in range of 1.8 to 2.0. The size of double strand cDNAs obtained by RT-PCR was more than 2 kb, which indicated that intact mRNA was obtained. The fragments of β-actin and chitinase gene from the RNA of C. anastomosis were obtained by RT-PCR, which indicated that the RNA could be used for other molecular operation. By this procedure, RNAs could be extracted and analyzed by electrophoresis from at least 8 samples within 4 hours. These results showed that this method was time- and cost-saving and effective. 展开更多
关键词 RNA isolation β-actin gene Clostera anastomosis Saperda populnea
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A Method Suitable for Extracting Genomic DNA from Animal and Plant——Modified CTAB Method 被引量:23
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作者 闫苗苗 魏光成 +2 位作者 潘效红 马怀雷 李伟振 《Agricultural Science & Technology》 CAS 2008年第2期39-41,共3页
[Objective] The study aimed to introduce a rapid and effective method that is suitable for extracting genomic DNA from animal and plant. [ Method ] The genomic DNAs were extracted from tender leaves of 24 peanut cuhiv... [Objective] The study aimed to introduce a rapid and effective method that is suitable for extracting genomic DNA from animal and plant. [ Method ] The genomic DNAs were extracted from tender leaves of 24 peanut cuhivars and from the liver, lung and kidney of white mouse through the specifically modified CTAB method. The DNAs were run on agarose gel, next detected by DNA/Protein analyzer. Finally PCR amplification was conducted to detect the quality of DNAs extracted using the modified CTAB method. [ Result] The clear and orderly bands were observed in gel detection, and the values of OD200/OD200 for DNAs extracted via modified CTAB method were between 1.77 - 1.83. The DNAs performed well in PCR amplification. [ Conclusion] The DNAs extracted by modified CTAB method could satisfy the requirement of PCR amplification. 展开更多
关键词 ANIMAL PLANT Extraction of genomic DNA Modified CTAB method
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Fast global motion estimation and moving object extraction algorithm in image sequences 被引量:2
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作者 张涛 费树岷 +1 位作者 李晓东 路红 《Journal of Southeast University(English Edition)》 EI CAS 2008年第2期192-196,共5页
A novel and effective approach to global motion estimation and moving object extraction is proposed. First, the translational motion model is used because of the fact that complex motion can be decomposed as a sum of ... A novel and effective approach to global motion estimation and moving object extraction is proposed. First, the translational motion model is used because of the fact that complex motion can be decomposed as a sum of translational components. Then in this application, the edge gray horizontal and vertical projections are used as the block matching feature for the motion vectors estimation. The proposed algorithm reduces the motion estimation computations by calculating the onedimensional vectors rather than the two-dimensional ones. Once the global motion is robustly estimated, relatively stationary background can be almost completely eliminated through the inter-frame difference method. To achieve an accurate object extraction result, the higher-order statistics (HOS) algorithm is used to discriminate backgrounds and moving objects. Experimental results validate that the proposed method is an effective way for global motion estimation and object extraction. 展开更多
关键词 global motion estimation edge projection higherorder statistics moving object extraction
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Motion connectivity-based initial video object extraction
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作者 王煜坚 吴镇扬 《Journal of Southeast University(English Edition)》 EI CAS 2007年第4期500-506,共7页
In order to obtain the initial video objects from the video sequences, an improved initial video object extraction algorithm based on motion connectivity is proposed. Moving objects in video sequences are highly conne... In order to obtain the initial video objects from the video sequences, an improved initial video object extraction algorithm based on motion connectivity is proposed. Moving objects in video sequences are highly connected and structured, which makes motion connectivity an advanced feature for segmentation. Accordingly, after sharp noise elimination, the cumulated difference image, which exhibits the coherent motion of the moving object, is adaptively thresholded. Then the maximal connected region is labeled, post-processed and output as the final segmenting mask. Hence the initial video object is effectively extracted. Comparative experimental results show that the proposed algorithm extracts the initial video object automatically, promptly and properly, thereby achieving satisfactory subjective and objective performance. 展开更多
关键词 video object extraction motion connectivity adaptive threshold cumulated difference image
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Discussion on Action and Potential of Fenlong Megascience in the Symbiosis between Human and Nature 被引量:3
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作者 韦本辉 申章佑 +6 位作者 周佳 周灵芝 李艳英 劳承英 甘秀芹 胡泊 韦元波 《Agricultural Science & Technology》 CAS 2017年第12期2303-2308,2311,共7页
The fourth new farming model Fenlong is identified as megascience for the first time. Fenlong can be directly applied to farming of farmland, remoulding of mortar black soil and saline alkali land and development of d... The fourth new farming model Fenlong is identified as megascience for the first time. Fenlong can be directly applied to farming of farmland, remoulding of mortar black soil and saline alkali land and development of degraded grassland. Deep loosening can create huge soil reservoirs, reduce fertilization, promote indi- rectly the improvement of river water fisheries and water sources and the upgrading of shaping and hydropower industry, thus making a new round of mobilization and pooling of natural resources. As a result, the nature is able to produce good food needed by human, the spatial dimension of the land is increased, the natural pre- cipitation storage is increased, the flood and drought disasters are reduced, the eco-environment is improved, and the economic benefits are increased. Fenlong is not restricted to global application by ecological region and crop variety and is not subject to the time-space constraints for a hundred thousand years. On the basis of utilizing the heaven and earth resources, it brings about a huge effect of mega- science. Compare with traditional farming, the depth under the mode of Fenlong is increased by 2-3 times, the contents of nutrient, water, oxygen and microorganism in the soil are increased by 10%-200%, the content of pale salt is increased by 20%-40%, the temperature is increased by 2-4 ~C, and the photosynthetic efficiency of crops is improved by 10%. Under the cultivation mode of Fenlong, the yield of crop applied with no fertilizers is increased by more than 10%, crop yield is still in- creased by more than 5% when the application amount of chemical fertilizer is re- duced by 10%-20%. Under the farming mode of Fenlong combined with no in- crease in fertilization, the crop yield, crop quality, farming efficiency, natural precipi- tation storage and air humidity are increased by 10%-50%, 5%, 15%, 100% and 5%, respectively, and the emissions of methane and other gases are reduced by more than 5%. Even in mortar black soil, saline alkali land and degraded grassland, the yield is still increased by 15%-50%. These improvement effects can last for many years, helping achieve the real harmonious coexistence between human and nature. 展开更多
关键词 Fenlong Megascience Autogeneration Yield and quality improvement Water conservation ecology Harmonious coexistence between human and nature
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关于阀响应时间的探讨
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作者 刘建新 《液压气动与密封》 1994年第3期54-56,共3页
关键词 响应时间 电磁先导式 提动
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Environmental availability and ecological risk assessment of heavy metals in zinc leaching residue 被引量:26
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作者 闵小波 谢先德 +3 位作者 柴立元 梁彦杰 李密 柯勇 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期208-218,共11页
Four different methods,namely mineralogical analysis,three-stage BCR sequential extraction procedure,dynamic leaching test and Hakanson Potential Ecological Risk Index Method were used to access the environmental acti... Four different methods,namely mineralogical analysis,three-stage BCR sequential extraction procedure,dynamic leaching test and Hakanson Potential Ecological Risk Index Method were used to access the environmental activity and potential ecological risks of heavy metals in zinc leaching residue.The results demonstrate that the environmental activity of heavy metals declines in the following order:CdZnCuAsPb.Potential ecological risk indices for single heavy metal are CdZnCuAsPb.Cd has serious potential ecological risk to the ecological environment and contributes most to the potential toxicity response indices for various heavy metals in the residue. 展开更多
关键词 heavy metals BCR sequential extraction environmental availability leaching toxicity dynamic leaching potential ecological risk index method zinc leaching residue
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Mechanism and kinetics of iron extraction from high silica boehmite−kaolinite bauxite by hydrochloric acid leaching 被引量:5
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作者 Dmitry VALEEV Denis PANKRATOV +5 位作者 Andrei SHOPPERT Artem SOKOLOV Alexandr KASIKOV Alexandra MIKHAILOVA Cristian SALAZAR-CONCHA Ilia RODIONOV 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第10期3128-3149,共22页
The chemical and mineral compositions of bauxite recovered from the Severoonezhsk Bauxite Mine(Arkhangelsk region,Russia)were studied by XRD,ICP-OES,TG/DSC,SEM,TEM,and Mössbauer spectroscopy.The iron-containing m... The chemical and mineral compositions of bauxite recovered from the Severoonezhsk Bauxite Mine(Arkhangelsk region,Russia)were studied by XRD,ICP-OES,TG/DSC,SEM,TEM,and Mössbauer spectroscopy.The iron-containing minerals of the bauxites were found to comprise alumogoethite(α-Fe_(1−x)Al_(x)OOH),alumohematite(α-(Fe_(1−x)Al_(x))_(2)O_(3)),alumoakaganeite(β-Fe_(1−x)Al_(x)O(OH,Cl)),and chromite(FeCr_(2)O_(4)).The efficiency of Fe extraction from the bauxite by HCl leaching was 82.5%at 100℃,HCl concentration of 10%,solid/liquid ratio of 1:10,and the process duration of 60 min,with aluminum loss from the bauxites below 4.5%of the total Al contents in the bauxite.Analysis of the kinetics of the iron leaching process proved diffusion to be the limiting stage of the process at 90−100℃.Bauxite residue after leaching presented traces of α-Fe_(1−x)Al_(x)OOH and β-Fe_(1−x)Al_(x)O(OH,Cl),and most of the iron content was in the FeCr_(2)O_(4).In bauxite residue after HCl leaching,in addition to iron oxide,the contents of chromium and calcium oxides significantly decreased.The iron chloride liquor after leaching contained the rare earth elements(REE)of 6.8 mg/L Sc,4.1 mg/L Ce and 2.3 mg/L Ga. 展开更多
关键词 BAUXITE acid leaching iron extraction KINETICS Mössbauer spectroscopy
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Investigation on the automatic parameters extraction of pulse signals based on wavelet transform 被引量:8
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作者 WANG Hui-yan ZHANG Pei-yong 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第8期1283-1289,共7页
This paper analyses a key problem in the quantification of pulse diagnosis. Due to the subjectivity and fuzziness of pulse diagnosis,quantitative methods are needed. To extract the parameters of pulse signals,the prer... This paper analyses a key problem in the quantification of pulse diagnosis. Due to the subjectivity and fuzziness of pulse diagnosis,quantitative methods are needed. To extract the parameters of pulse signals,the prerequisite is to detect the corners of pulse signals correctly. Up to now,the pulse parameters are mostly acquired by marking the pulse corners manually,which is an obstacle to modernize pulse diagnosis. Therefore,a new automatic parameters extraction approach for pulse signals using wavelet transform is presented. The results testified that the method we proposed is feasible and effective and can detect corners of pulse signals accurately,which can be expected to facilitate the modernization of pulse diagnosis. 展开更多
关键词 Pulse signal Feature extraction Complex wavelet transform Quantitative diagnosis
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Study on calculation for the position and scope of tropical cyclone
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作者 刘永禄 邵利民 郎丰旺 《Marine Science Bulletin》 CAS 2013年第2期37-45,共9页
The scale, shape and position are three main factors to forecast tropical cyclone. The aim of the paper is to recognize tropical cyclone (TC) in the satellite cloud pictures according to the scale, shape and positio... The scale, shape and position are three main factors to forecast tropical cyclone. The aim of the paper is to recognize tropical cyclone (TC) in the satellite cloud pictures according to the scale, shape and position of clouds. The study includes Canny edge detection, contour extraction and other techniques. The solutions are also established. The experiments show that the method can recognize the TC in the satellite pictures. The study is beneficial for TC track. 展开更多
关键词 tropical cyclone (TC) Canny edge detection contour extraction automation recognition
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Kinetics of Leaching Flavonoids from Pueraria Lobata with Ethanol 被引量:5
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作者 池汝安 田君 +4 位作者 高洪 周芳 刘敏 王存文 吴元欣 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2006年第3期402-406,共5页
The kinetics of leaching flavonoids from Pueraria Lobata with ethanol was investigated. The effects of leaching temperature, mechanical agitation rate, concentration of ethanol and feed particle size on leaching kinet... The kinetics of leaching flavonoids from Pueraria Lobata with ethanol was investigated. The effects of leaching temperature, mechanical agitation rate, concentration of ethanol and feed particle size on leaching kinetics were examined. It is found that the smaller the feed particle size or the higher the leaching temperature, the higher the leaching rate. The leaching process can be described by the shrinking-core model. The apparent activation energy is 10.8kJ·mol^-1, suggesting that the leaching process is controlled by the inner diffusion. An empirical equation relating the flavonoids leaching rate constant to the feed particle size and leaching temperature was expected. 展开更多
关键词 KINETICS LEACHING FLAVONOIDS Pueraria Lobata
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Kinetics of leaching lithium from α-spodumene in enhanced acid treatment using HF/H_2SO_4 as medium 被引量:11
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作者 Hui GUO Hai-zhao YU +4 位作者 An-an ZHOU Meng-hua Lü Qiao WANG Ge KUANG Hai-dong WANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第2期407-415,共9页
An enhanced leaching of Li fromα-spodumene was carried out using a mixture of hydrofluoric and sulfuric acid(HF/H2SO4)as the medium.Based on the optimized leaching conditions,the leaching kinetics of Li was investiga... An enhanced leaching of Li fromα-spodumene was carried out using a mixture of hydrofluoric and sulfuric acid(HF/H2SO4)as the medium.Based on the optimized leaching conditions,the leaching kinetics of Li was investigated in an ore/HF/H2SO4 ratio of 1:3:2 g:mL:mL with leaching temperature ranging from 50 to 100°C.The results indicate that the leaching kinetics of Li fitted well with a model based on the shrinking core model.In addition,the leaching rate of Li was controlled by chemical reactions and diffusion through the product layers.The apparent activation energy Ea was calculated to be 32.68 kJ/mol.Solid films were formed because of the generation of insoluble products such as cryolithionite(Na3Li2Al2F12),cryolite(Na3AlF6),calcium fluoride(CaF2),potassium cryolite(K2AlF5),aluminum fluoride(AlF3),and fluorosilicates(Na2SiF6 or KNaSiF6).Furthermore,the effects of the ore/HF ratio and leaching temperature on the leaching behavior of Li,Al and Si were investigated.The results indicate that the ore/HF ratio and leaching temperature could clearly affect the distribution of HF molecules on the leaching of Li,Al and Si,which are important for the selective leaching of Li over Al and Si with this fluorine-based chemical method. 展开更多
关键词 α-spodumene lithium extraction leaching kinetics hydrofluoric acid fluorine-based chemical method
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Automatically extracting sheet-metal features from solid model 被引量:3
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作者 刘志坚 李建军 +2 位作者 王义林 李材元 肖祥芷 《Journal of Zhejiang University Science》 EI CSCD 2004年第11期1456-1465,共10页
With the development of modern industry, sheet-metal parts in mass production have been widely applied in mechanical, communication, electronics, and light industries in recent decades; but the advances in sheet-metal... With the development of modern industry, sheet-metal parts in mass production have been widely applied in mechanical, communication, electronics, and light industries in recent decades; but the advances in sheet-metal part design and manufacturing remain too slow compared with the increasing importance of sheet-metal parts in modern industry. This paper proposes a method for automatically extracting features from an arbitrary solid model of sheet-metal parts; whose characteristics are used for classification and graph-based representation of the sheet-metal features to extract the features embodied in a sheet-metal part. The extracting feature process can be divided for valid checking of the model geometry, feature matching, and feature relationship. Since the extracted features include abundant geometry and engineering information, they will be effective for downstream application such as feature rebuilding and stamping process planning. 展开更多
关键词 Sheet-metal part Feature extraction Feature representation
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A New Treatment of Depression for Drainage Network Extraction Based on DEM 被引量:4
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作者 WANG Yan PENG Hong +3 位作者 CUI Peng ZHANG Wanshun QIAO Fei CHEN Cai'er 《Journal of Mountain Science》 SCIE CSCD 2009年第4期311-319,共9页
Depressions in landscapes function as buffers for water and sediment. A landscape with depressions has less runoff, less erosion and more sedimentation than that without depressions. Sinks in digital elevation models ... Depressions in landscapes function as buffers for water and sediment. A landscape with depressions has less runoff, less erosion and more sedimentation than that without depressions. Sinks in digital elevation models (DEMs) can be considered the real features that represent depressions in actual landscapes or spurious features that result from errors in DEM creation. In many hydrological and erosion models, all sinks are considered as spurious features and, as a result, these models do not deal with the sinks that represent real depressions. Consequently, the surface runoff and erosion are overestimated due to removing the depressions. Aiming at this problem, this paper presents a new method, which deal with the sinks that represent real depressions. The drainage network is extracted without changing the original DEM. The method includes four steps: detecting pits, detecting depressions, merging depressions, and extracting drainage network. Because the elevations of grid cells are not changed, the method can also avoid producing new fiat areas, which are always produced by the conventional filling methods. The proposed method was applied to the Xihanshui River basin, the upper reach of the Jialingjiang River basin, China, to automatically extract the drainage network based on DEM. The extracted drainage network agrees well with the reality and can be used for further hydrologic analysis and erosion estimation. 展开更多
关键词 Drainage network extraction Depression processing Digital elevation model Wooden barrel effect Xihanshui River basin.
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Stress Analysis of Top Tensioned Riser Under Random Waves and Vessel Motions 被引量:11
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作者 LI Xiaomin GUO Haiyan MENG Fanshun 《Journal of Ocean University of China》 SCIE CAS 2010年第3期251-256,共6页
The bending stresses of top tensioned riser(TTR) under combined excitations of currents,random waves and vessel motions are presented in this paper,and the effect of the internal flowing fluid on the riser stresses is... The bending stresses of top tensioned riser(TTR) under combined excitations of currents,random waves and vessel motions are presented in this paper,and the effect of the internal flowing fluid on the riser stresses is also considered.The computation programs which are used to solve the differential equations in the time domain are compiled and the principal factors of concern including the angular movements at the upper and lower ends of the riser,lateral displacements and bending stresses are presented.Then the effects of current velocity,random wave,top tension,vessel mean offset,low frequency motion and internal flow velocity on the bending stresses of the riser are analyzed in detail. 展开更多
关键词 top tensioned riser (TTR) internal flow vessel motion dynamic response
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A Semi-automatic Method Based on Statistic for Mandarin Semantic Structures Extraction in Specific Domains 被引量:1
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作者 熊英 朱杰 孙静 《Journal of Shanghai Jiaotong university(Science)》 EI 2004年第4期25-29,共5页
This paper proposed a new method of semi-automatic extraction for semantic structures from unlabelled corpora in specific domains. The approach is statistical in nature. The extracted structures can be used for shallo... This paper proposed a new method of semi-automatic extraction for semantic structures from unlabelled corpora in specific domains. The approach is statistical in nature. The extracted structures can be used for shallow parsing and semantic labeling. By iteratively extracting new words and clustering words, we get an inital semantic lexicon that groups words of the same semantic meaning together as a class. After that, a bootstrapping algorithm is adopted to extract semantic structures. Then the semantic structures are used to extract new 展开更多
关键词 and augment the semantic lexicon. The resultant semantic structures are interpreted by persons and are amenable to hand-editing for refinement. In this experiment the semi-automatically extracted structures S SA provide recall rate of 84.
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Kinetic Study of Hydrothermal Stripping from Iron-Loaded Organic Phase 被引量:1
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作者 王兴尧 韩珺圆 +3 位作者 杨桂琴 卢立柱 谢慧琴 康晓红 《Transactions of Tianjin University》 EI CAS 2007年第2期113-116,共4页
The iron-loaded organic phase of naphthenic acid-isooctyl alcohol-kerosene was prepared, and the process kinetics of hydrothermal stripping of iron from the phase was studied. Several factors affecting hydrothermal st... The iron-loaded organic phase of naphthenic acid-isooctyl alcohol-kerosene was prepared, and the process kinetics of hydrothermal stripping of iron from the phase was studied. Several factors affecting hydrothermal stripping, such as the polymer of naphthenic acid, initial concentrations of iron and naphthenic acid, temperature and agitation time, were investigated, and based on experimental results and theoretical analysis, two kinetic models were established.The stripping rate equation suggests that the hydrothermal stripping process activation energy is 96.4 kJ·mol-1 and the stripping is controlled by hydrolysis of naphthenic complex of iron. The values calculated by the stripping fraction equation comparatively accord with the experimental data. 展开更多
关键词 hydrothermal stripping rate equation activation energy stripping fraction
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