期刊文献+
共找到149篇文章
< 1 2 8 >
每页显示 20 50 100
“极物之真,能守其本”——谈韩贤杰朝鲜族舞蹈创作中的“物象”思维
1
作者 赵凯 《北京舞蹈学院学报》 CSSCI 2018年第3期67-71,共5页
多年以来,一直致力于朝鲜族舞蹈教学和创作的韩贤杰老师,在不断的创作实践中形成了自己独特的创作理念和作品风格。从作品《沐月行》《月光-处容》(1)《鹤在飞!》中,可以看出韩贤杰教授朝鲜族舞蹈编创的特点——对"物象"(自... 多年以来,一直致力于朝鲜族舞蹈教学和创作的韩贤杰老师,在不断的创作实践中形成了自己独特的创作理念和作品风格。从作品《沐月行》《月光-处容》(1)《鹤在飞!》中,可以看出韩贤杰教授朝鲜族舞蹈编创的特点——对"物象"(自然之物、图腾之物)的敏锐感悟与外化,以及在此基础上对传统的尊重,对朝鲜族舞蹈人文内涵的挖掘。韩贤杰老师创作观念中有着朴实的庄子"极物之真"的智慧,正是在这样的中国哲学思维意识引导下,他对朝鲜民族传统语言进行了再创造和再发展,并形成了他朝鲜族舞蹈作品独特的艺术品性。 展开更多
关键词 韩贤杰 朝鲜族舞蹈 “物象”思维
原文传递
谈静物素描教学的难点——物象的立体感、空间感、重量感和质感 被引量:2
2
作者 孙德元 《成都教育学院学报》 2006年第1期127-128,共2页
关键词 静物素描教学 教学难点 “物象的立体感、空间感、重量感和质感” 中等职业学校 美术教学
下载PDF
“媒介消费主义”对近年来中国电影作品形态的影响 被引量:1
3
作者 叶凯 《浙江传媒学院学报》 2018年第3期72-76,共5页
"媒介消费主义"是在当下中国媒介融合联动的大背景下,依托移动互联网与自媒体平台的活力催化作用,将消费社会呈现出的"物的包围"现象,于虚拟空间内进行的"视像化"阐释与解构。依旧遵循着大众在对"物... "媒介消费主义"是在当下中国媒介融合联动的大背景下,依托移动互联网与自媒体平台的活力催化作用,将消费社会呈现出的"物的包围"现象,于虚拟空间内进行的"视像化"阐释与解构。依旧遵循着大众在对"物象"膜拜依恋中逐渐养成的"代理参与"幻觉机制,"媒介消费主义"以跨媒介的"互文"传播、日常景观的视觉迷恋,形构了近年来中国电影创作中IP改编、青春片、综艺片等流行热潮,并融入主流电影作品的话语表述策略,以"替换性"的修饰手法,完成了适应时代主题的叙事重构与消费再现。 展开更多
关键词 媒介消费主义 “物象”替换 叙事改写 审美位移 价值转向
下载PDF
Transition metal coordination polymers with flexible dicarboxylate ligand:Synthesis,characterization,and photoluminescence property
4
作者 CUI Peipei LI Xin +5 位作者 CHEN Yilin CHENG Zhilin GAO Feiyan GUO Xu YAN Wenning DENG Yuchen 《无机化学学报》 SCIE CAS CSCD 北大核心 2024年第11期2221-2231,共11页
Under solvothermal conditions,six new coordination polymers(CPs)[Mn(L)(phen)(H_(2)O)]_(n)(1),[Co(L)(phen)(H_(2)O)]_(n)(2),[Cu(L)(phen)(H_(2)O)]_(n)(3),[Zn_(2)(L)_(2)(phen)2(H_(2)O)]_(n)(4),[Zn(L)(phen)]_(n)(5),and[Cd(... Under solvothermal conditions,six new coordination polymers(CPs)[Mn(L)(phen)(H_(2)O)]_(n)(1),[Co(L)(phen)(H_(2)O)]_(n)(2),[Cu(L)(phen)(H_(2)O)]_(n)(3),[Zn_(2)(L)_(2)(phen)2(H_(2)O)]_(n)(4),[Zn(L)(phen)]_(n)(5),and[Cd(L)(phen)2]_(n)(6)were synthesized by reactions of dicarboxylate ligand 2,2'-(1,2-phenylenebis(methylene))bis(sulfanediyl)dinobutyric acid(H_(2)L)and 1,10-phenanthroline(phen)with the corresponding metal salts.Complexes 1-6 have been structurally characterized by single-crystal X-ray diffraction analyses,elemental analysis,IR,thermogravimetric analysis,and powder X-ray diffraction.The structures of 1-6 are 1D chains,which are further connected by hydrogen bonding interac-tions to form 3D supramolecular structures.Among them,1 and 2 are isomorphic with L2-of syn-conformation,while L2-shows anti-conformation in 3-6.In addition,the solid-state photoluminescence property of 4-6 was investigated. 展开更多
关键词 flexible dicarboxylate ligand coordination polymers hydrogen bonding interaction CONFORMATION photoluminescence property
下载PDF
论悟性认识层阶的“领悟”思维形式 被引量:1
5
作者 李洪君 李丹宇 《东莞理工学院学报》 2017年第6期19-26,共8页
领悟思维形式是在"感悟思维形式"基础上的跃迁。领悟思维形式,是人类原始先民在生存劳动和氏族群体生活中,对"感悟思维"形式进行初级熔炼综合和初级凝炼整合的方式,即"悟象"的多种表象("物象"... 领悟思维形式是在"感悟思维形式"基础上的跃迁。领悟思维形式,是人类原始先民在生存劳动和氏族群体生活中,对"感悟思维"形式进行初级熔炼综合和初级凝炼整合的方式,即"悟象"的多种表象("物象"或"物象群"或"表象群"或者"意象"或"意象群")等形式和记忆,进行彼此之间的沟通和交流(信息互换),信息接受的一方,依据自己在劳动活动和群体生活中积累的"经验",通过情感、联想、想象等心理活动创造"内心视象"或象境,达到某种沟通或交流的领会状态。它与"感悟思维形式"一样也是朦胧地表达出人类祖先思维历史发展的雏形状态。 展开更多
关键词 悟性认识 “领悟”思维形式 “物象” “意象” “悟象”
下载PDF
LOCALIZATION OF OBJECT (SPINE) IN MEDICAL IMAGE USING ACTIVE SHAPE MODELS 被引量:2
6
作者 徐涛 蔡宇新 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2003年第2期211-217,共7页
Active shape models (ASM), consisting of a shape model and a local gray-level appearance model, can be used to locate the objects in images. In original ASM scheme, the model of object′s gray-level variations is base... Active shape models (ASM), consisting of a shape model and a local gray-level appearance model, can be used to locate the objects in images. In original ASM scheme, the model of object′s gray-level variations is based on the assumption of one-dimensional sampling and searching method. In this work a new way to model the gray-level appearance of the objects is explored, using a two-dimensional sampling and searching technique in a rectangular area around each landmark of object shape. The ASM based on this improvement is compared with the original ASM on an identical medical image set for task of spine localization. Experiments demonstrate that the method produces significantly fast, effective, accurate results for spine localization in medical images. 展开更多
关键词 object localization active shape models (ASM) gray-level appearance model principal component analysis SPINE
下载PDF
The Interaction of Ribavirin and DII-18-2 with RNA
7
作者 郝美荣 杨铭 《Journal of Chinese Pharmaceutical Sciences》 CAS 2001年第3期124-127,共4页
The aim of this study was to investigate the interaction between polymers polyApolyU (RNA) and two general anti-viral drugs with anti-HIV-1 activities. Tm experiment showed that the compounds had interacted with RNA, ... The aim of this study was to investigate the interaction between polymers polyApolyU (RNA) and two general anti-viral drugs with anti-HIV-1 activities. Tm experiment showed that the compounds had interacted with RNA, and CD spectra also observed the changes of RNA conformation induced by the compounds. Cytometric flow analysis indicated that ribavirin and DII-18-2 could decrease the percentage of hypodiploid cells, especially ribavirin. 展开更多
关键词 RNA CONFORMATION TM
下载PDF
Pesticidal character of phytoecdysteroids from Ajuga multiflora Bunge (Labiatae) on larvae of Cryptorrhynchus lapathi L. (Coleoptera: Curculionidae)
8
作者 迟德富 孙明学 夏文富 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第3期177-182,250,共6页
Eight kinds of phytoecdysteroids extracted from different parts of Ajuga multiflora Bunge (Labiatae) that were collected from different places at different time were tested for killing effects on the 2-instar larvae o... Eight kinds of phytoecdysteroids extracted from different parts of Ajuga multiflora Bunge (Labiatae) that were collected from different places at different time were tested for killing effects on the 2-instar larvae of Cryptorrhynchus lapathi L by adding them to the artificial diet of larvae. The experimental results indicated that adding 1-3-mL phytoecdysteroids to the artificial diet could lead 58%-100% of 2-instar larvae of C. lapathi to death within 24 days. The phytoecdysteroids extracted from the whole plant of A. multiflora which was collected before flowering time were much more effective than those extracted from the plants collected at flowering and after flowering periods, and the modified mortality rate of larvae reached 65.22%, 85.07%, and 98.11% at the dosage level of 1-mL, 2-mL, and 3-mL extracts, respectively. The extract made from root of A. multiflora plant was more effective in killing efficiency than those from stem and leaves, and the average death rates of larvae were up to 100%, 98.20% and 98.32% at dosage levels of 1-mL, 2-mL, and 3-mL extracts, respectively. The killing speed of the extracted phytoecdysteroids was slower than that of triflumuron, hexaflumuron or deltamethrin emulsifiable concentrate. The mortality rate of larvae is closely related to the feeding duration on the diets containing phytoecdysteroids. Feeding on the diets with addition of phytoecdysteroids for 16 days, more than 80% of treated 2-instar larvae of C. lapathi were led to death. The killing effect of the extracts was little affected by the growth areas of A. multiflora plant and the adding way to artificial diet. 展开更多
关键词 Ajuga multifora Bunge Cryptorrhynchus lapathi L. Larva Phytoecdysteroid
下载PDF
Automatic character detection and segmentation in natural scene images 被引量:12
9
作者 ZHU Kai-hua QI Fei-hu +1 位作者 JIANG Ren-jie XU Li 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第1期63-71,共9页
We present a robust connected-component (CC) based method for automatic detection and segmentation of text in real-scene images. This technique can be applied in robot vision, sign recognition, meeting processing and ... We present a robust connected-component (CC) based method for automatic detection and segmentation of text in real-scene images. This technique can be applied in robot vision, sign recognition, meeting processing and video indexing. First, a Non-Linear Niblack method (NLNiblack) is proposed to decompose the image into candidate CCs. Then, all these CCs are fed into a cascade of classifiers trained by Adaboost algorithm. Each classifier in the cascade responds to one feature of the CC. Proposed here are 12 novel features which are insensitive to noise, scale, text orientation and text language. The classifier cascade allows non-text CCs of the image to be rapidly discarded while more computation is spent on promising text-like CCs. The CCs passing through the cascade are considered as text components and are used to form the segmentation result. A prototype system was built, with experimental results proving the effectiveness and efficiency of the proposed method. 展开更多
关键词 Text detection and segmentation ADABOOST NLNiblack decomposition method Attentional cascade
下载PDF
Assessment of Sediment and Pollutants in Buyo Lake, Ivory Coast, Using SWAT (Soil and Water Assessment Tool) Model 被引量:7
10
作者 Tanoh Jean-Jacques Koua Jean Patrice Jourda +1 位作者 Kan Jean Kouame Kouao Armand Anoh 《Journal of Chemistry and Chemical Engineering》 2013年第11期1054-1059,共6页
The changes in land use in the last 30 years in the territory of agro-forest watershed of Lake Buyo resulted in significant sediment into the lake. Sediments are a preferred means of transportation for certain polluta... The changes in land use in the last 30 years in the territory of agro-forest watershed of Lake Buyo resulted in significant sediment into the lake. Sediments are a preferred means of transportation for certain pollutants, like phosphorus in excess. By mapping the source areas of erosion, the authors can determine the risk areas and help to prioritize interventions in the territory. This mapping is done using the SWAT (soil and water assessment tool) model. Several types of data, including topography, land use, soil and climate data are needed to run the model. In this paper, all different steps are presented, from the designing of HRU (hydrological response units), basic units to run the SWAT model until the simulations. The establishment of HRU has three main stages: space discretization, land use and soil data integration and HRU distribution: (1) space discretization which consist in extracting the limits and the water network of the watershed from the DEM (digital elevation model) and in subdividing them into sub-basins; (2) land use and soil data integration: it consists in digitizing the physical maps of land use and of soils under Mapinfo 7.5 and in keeping them in "shape" format; (3) HRU distribution: it leads to subdivide the sub-watersheds in small units that combine a single soil type and one type of land use. It appears from this study to obtain 23 sub-watersheds and 71 HRU. Once the HRU designed, it is necessary to integrate climate data, data on physico-chemical characteristics of soils and agricultural practices, before starting the simulations. This will allow the model to assess the risk of sedimentation and eutrophication of the lake using the MUSLE (modified universal soil loss equation) and phosphorus cycle. 展开更多
关键词 Erosion land use SWAT MODEL PHOSPHORUS sediment.
下载PDF
从《豹》看里尔克对法国象征主义的接受与发展
11
作者 陈利利 《西安外国语大学学报》 2009年第1期33-35,42,共4页
象征主义作为法国文学史上的一个流派,从形成到完善历经了很长的时间,也在法国乃至全世界产生了极其深刻的影响。法国象征主义体现在小说、绘画和戏剧等诸多领域,但其突出的成就则在诗歌方面。20世纪初的后期象征主义在德语诗人中的代... 象征主义作为法国文学史上的一个流派,从形成到完善历经了很长的时间,也在法国乃至全世界产生了极其深刻的影响。法国象征主义体现在小说、绘画和戏剧等诸多领域,但其突出的成就则在诗歌方面。20世纪初的后期象征主义在德语诗人中的代表人物之一里尔克在接受法国象征主义影响的同时,也形成了自己一系列独特的风格。 展开更多
关键词 象征主义 《豹》 里尔克 “物象诗”
下载PDF
Chronic proctalgia and chronic pelvic pain syndromes:New etiologic insights and treatment options 被引量:12
12
作者 Giuseppe Chiarioni Corrado Asteria William E Whitehead 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第40期4447-4455,共9页
This systematic review addresses the pathophysiology, diagnostic evaluation, and treatment of several chronic pain syndromes affecting the pelvic organs:chronic proctalgia, coccygodynia, pudendal neuralgia, and chroni... This systematic review addresses the pathophysiology, diagnostic evaluation, and treatment of several chronic pain syndromes affecting the pelvic organs:chronic proctalgia, coccygodynia, pudendal neuralgia, and chronic pelvic pain. Chronic or recurrent pain in the anal canal, rectum, or other pelvic organs occurs in 7% to 24% of the population and is associated with impaired quality of life and high health care costs. However, these pain syndromes are poorly understood, with little research evidence available to guide their diagnosis and treatment. This situation appears to be changing:A recently published large randomized,controlled trial by our group comparing biofeedback, electrogalvanic stimulation, and massage for the treatment of chronic proctalgia has shown success rates of 85% for biofeedback when patients are selected based on physical examination evidence of tenderness in response to traction on the levator ani muscle-a physical sign suggestive of striated muscle tension. Excessive tension (spasm) in the striated muscles of the pelvic floor appears to be common to most of the pelvic pain syndromes. This suggests the possibility that similar approaches to diagnostic assessment and treatment may improve outcomes in other pelvic pain disorders. 展开更多
关键词 BIOFEEDBACK Chronic pelvic pain Chronicproctalgia COCCYGODYNIA Levator ani syndrome Pudendal neuralgia
下载PDF
Physically based modeling and animation of tornado 被引量:3
13
作者 LIU Shi-guang WANG Zhang-ye +2 位作者 GONG Zheng CHEN Fei-fei PENG Qun-sheng 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第7期1099-1106,共8页
Realistic modeling and rendering of dynamic tornado scene is recognized as a challenging task for researchers of computer graphics. In this paper a new physically based method for simulating and animating tornado scen... Realistic modeling and rendering of dynamic tornado scene is recognized as a challenging task for researchers of computer graphics. In this paper a new physically based method for simulating and animating tornado scene is presented. We first propose a Two-Fluid model based on the physical theory of tornado, then we simulate the flow of tornado and its interaction with surrounding objects such as debris, etc. Taking the scattering and absorption of light by the participating media into account, the illumination effects of the tornado scene can be generated realistically. With the support of graphics hardware, various kinds of dynamic tornado scenes can be rendered at interactive rates. 展开更多
关键词 Natural phenomenon Tornado scene Physically based simulation Two-Fluid model
下载PDF
Characteristics of liver on magnetic resonance diffusion-weighted imaging:Dynamic and image pathological investigation in rabbit liver VX-2 tumor model 被引量:10
14
作者 You-Hong Yuan En-Hua Xiao +6 位作者 Jian-Bin Liu Zhong He Ke Jin Cong Ma Jun Xiang Jian-Hua Xiao Wei-Jian Chen 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第25期3997-4004,共8页
AIM: To investigate dynamical and image pathological characteristics of the liver on magnetic resonance (MR) diffusion-weighted imaging (DWI) in the rabbit VX-2 tumor model. METHODS: Forty New Zealand rabbits we... AIM: To investigate dynamical and image pathological characteristics of the liver on magnetic resonance (MR) diffusion-weighted imaging (DWI) in the rabbit VX-2 tumor model. METHODS: Forty New Zealand rabbits were included in the study and VX-2 tumor piece was implanted intrahepatically. Fifteen animals received two intrahepatic implantations while 25 had one intrahepatical implantation. DWI, T1- and T2-weighted of magnetic resonance imaging (MRI) were carried out on the 7th and the 14th d after implantation and DWI was conducted, respectively on the 21th d. Ten VX-2 tumor samples were studied pathologically. RESULTS: The rate of lump detected by DWI, TlWI and T2WI was 78.7%, 10.7% and 53.5% (X^2 =32.61, P 〈 0.001) on the 7th d after implantation and 95.8%, 54.3% and 82.9% (X^2 = 21.50, P 〈 0.001) on the 14th d. The signal of most VX-2 tumors on DWI was uniform and it was equal diffusion coefficient (ADC). did not decrease on the 7th on the map of apparent The signal of VX tumors d after implantation, most of them slowly growing during the week following implantation without significant cell dying within the tumor. VX-2 tumors grew increasingly within 14 d after implantation but the signal of most VX-2 tumors on DWI or on the map of ADC was uniform or uneven and ADC of VX tumors decreased obscurely or slightly because tumor necrosis was still not obvious. On the 21th d after implantation, the signal of most VX-2 tumors on DWI or on the map of ADC was uneven because tumor necrosis was evident and ADC of VX-2 tumor necrotic areas decreased. The areas of viable cells in VX-2 tumors manifested a high signal on DWI and a low signal on the map of ADC. The areas of dead cells or necrosis in VX-2 tumors manifested low signals on DWI and low, equal or high signals on the map of ADC but they manifested high signals on DWI and on the map of ADC at the same time when the areas of necrotic tumor became liquefied or cystic. The border of tumors on DWI appeared gradually distinct and internal signals of tumor became progressively uneven. CONCLUSION: The manifestations of viable, necrotic and liquefied or cystic areas in VX-2 tumors on DWI are typical and DWI is of significant and potential values in clinical application in both the early detection and diagnosis of liver tumors. 展开更多
关键词 LIVER VX-2 tumor Diffusion-weightedimaging Apparent Diffusion Coefficient RABBIT
下载PDF
Arabidopsis RAV1 is down-regulated by brassinosteroid and may act as a negative regulator during plant development 被引量:57
15
作者 YuXinHU YongHongWANG XinFangLIU JiaYangLI 《Cell Research》 SCIE CAS CSCD 2004年第1期8-15,共8页
RAV1 is a novel DNA-binding protein with two distinct DNA-binding domains unique in higher plants,but its role in plant growth and development remains unknown. Using cDNA array,we found that transcription of RAV1 is d... RAV1 is a novel DNA-binding protein with two distinct DNA-binding domains unique in higher plants,but its role in plant growth and development remains unknown. Using cDNA array,we found that transcription of RAV1 is downregulated by epibrassinolide (epiBL) in Arabidopsis suspension cells. RNA gel blot analysis revealed that epiBL-regulated RAV1 transcription involves neither protein phosphorylation/dephosphorylation nor newly synthesized protein,and does not require the functional BRI1,suggesting that this regulation might be through a new BR signaling pathway.Overexpressing RAV1 in Arabidopsis results in a retardation of lateral root and rosette leaf development,and the underexpression causes an earlier flowering phenotype,implying that RAV1 may function as a negative regulatory component of growth and development. 展开更多
关键词 RAV1 BRASSINOSTEROID signal transduction Arabidopsis thaliana.
下载PDF
Impact of Human Activities on Depositional Process of Tidal Flat in Quanzhou Bay of China 被引量:8
16
作者 Wang Aijun 《Chinese Geographical Science》 SCIE CSCD 2007年第3期265-269,共5页
As a very important component of a coastal system, tidal flats come to be a focus of the studies on land-ocean interaction in the coastal zone because those areas are subjected to intense human activities and are high... As a very important component of a coastal system, tidal flats come to be a focus of the studies on land-ocean interaction in the coastal zone because those areas are subjected to intense human activities and are highly sensitive to the global change. The Quanzhou Bay, located along the middle part of Fujian coast of China, covers about 136.4km^2, and the area of coastal wetland in the entire bay from intertidal to subtidal with 6m of water depth accounts for 96% of the total area. Seven short cores were collected and divided in situ with the interval of 5cm on the coastal wetlands of Quanzhou Bay on April 19, 2006. The sediment samples were scattered and the grain sizes were measured by using Mastersizer 2000. Human beings' activities on tidal fiat have disturbed the vertical distribution of sediments in stratigraphic sequence and accelerated the sedimentation rates. Grain size analysis results show that the grain size diameters increase and sediment becomes worse sorted towards the sea under the strong human disturbance; Spartina alterniflora can play a role of trapping the fine sediment; but near the bank, the sediment becomes coarse and there are two peak values on frequency curve influenced by the sandpile. The trough formed by human activities along the coastline changes the transport path of water and suspended sediment. The sediments are transported through the trough and deposit in it during the flood; the ebb flow is retarded by the flow output through the adjacent trough, and the deposited sediment can not be re-suspended; then, the sedimentation rate increases. In situ observation show that the sedimentation rate is about 8-10cm/yr. 展开更多
关键词 tidal flat sediment grain size human activities sedimentation rate Quanzhou Bay
下载PDF
ATMOSPHERIC BOUNDARY LAYER CONCEPT MODEL OF THE PEARL RIVER DELTA AND ITS APPLICATION 被引量:4
17
作者 范绍佳 王安宇 +3 位作者 樊琦 刘吉 王宝民 塔纳 《Journal of Tropical Meteorology》 SCIE 2007年第1期8-13,共6页
Based on the geographical circumstance, climate and the boundary layer meteorology features of the Pearl River Delta, a boundary layer concept model of the Pearl River Delta was built. The concept model consists of fo... Based on the geographical circumstance, climate and the boundary layer meteorology features of the Pearl River Delta, a boundary layer concept model of the Pearl River Delta was built. The concept model consists of four fundamental factors that affect the boundary layer meteorology of the Pearl River Delta and can convincingly explain the reason of the air quality change in the Pearl River Delta. The model can be used to the diffusion capability analysis, the air pollution potential forecasting or haze forecasting, etc. 展开更多
关键词 boundary layer concept model Pearl River Delta
下载PDF
Influence of Mg_3N_2 powder on microstructures and mechanical properties of AZ31 Mg alloy 被引量:5
18
作者 赵红亮 周占霞 +1 位作者 刘旭东 关绍康 《Journal of Central South University of Technology》 2008年第4期459-462,共4页
In order to obtain an effective and reliable grain refiner for Mg-Al alloys, 1% (mass fraction) Mg3N2 was added into AZ31 Mg alloy. The microstructures of the Mg alloys were studied by optical microscopy, scan elect... In order to obtain an effective and reliable grain refiner for Mg-Al alloys, 1% (mass fraction) Mg3N2 was added into AZ31 Mg alloy. The microstructures of the Mg alloys were studied by optical microscopy, scan electron microscopy and X-ray energy dispersive spectroscopy, and the mechanical properties were determined. The results show that adding a small amount of Mg3N2 to AZ31 Mg alloy can refine the grain size from 103 to 58 μm. The ultimate tensile strength and elongation of AZ31 Mg alloy are 174.1MPa and 8.3%, respectively. After the addition of 1% Mg3N2, the ultimate tensile strength and elongation of AZ31 Mg alloy are increased up to 198.7 MPa and 11.8%, respectively. The grain refinement mechanism is that AIN is formed after Mg3N2 is added. Both AIN and Mg phases are of HCP lattice structure, and the disregistry between Mg phases and AIN along (0001)Mg//(0001)AIN is 3.04%, which is very effective for heterogeneous nucleation. 展开更多
关键词 Mg alloy Mg3N2 inoculation heterogeneous nucleation
下载PDF
A populational survey of 45S rDNA polymorphism in the Jefferson salamander Ambystoma jeffersonianum revealed by fluorescence in situ hybridization(FISH) 被引量:2
19
作者 James P. BOGART 《Current Zoology》 SCIE CAS CSCD 北大核心 2009年第2期145-149,共5页
The chromosomal localization of 45S ribosomal RNA genes in Ambystoma jeffersonianum was determined by fluorescence in situ hybridization with 18S rDNA fragment as a probe (FISH-rDNA). Our results revealed the presence... The chromosomal localization of 45S ribosomal RNA genes in Ambystoma jeffersonianum was determined by fluorescence in situ hybridization with 18S rDNA fragment as a probe (FISH-rDNA). Our results revealed the presence of rDNA polymorphism among A.jeffersonianum populations in terms of number,location and FISH signal intensity on the chromosomes. Nine rDNA cytotypes were found in ten geographically isolated populations and most of them contained derivative rDNA sites. Our preliminary study provides strong indication of karyotypic diversification of A.jeffersonianum that is demonstrated by intraspecific variation of 45S rDNA cytotypes. rDNA cytotype polymorphism has been described in many other caudate amphibians. We predict that habitat isolation,low dispersal ability and decline of effective population size could facilitate the fixation and accumulation of variable rDNA cytotypes during their chromosome evolution. 展开更多
关键词 RDNA POLYMORPHISM Jefferson salamander Ambystoma jeffersonianum Fluorescence in situ hybridization FISH-rDNA
下载PDF
Variability of the Continental Water Boundary near the Prydz Bay 被引量:3
20
作者 蒲书箴 董兆乾 +2 位作者 胡筱敏 于非 赵新 《Marine Science Bulletin》 CAS 2002年第1期1-10,共10页
Based on the data obtained during the 15th Antarctic Expedition of China between November 1998 and February 1999, the paper discusses the water masses distributed on both sides of the Continental Water Boundary (CWB) ... Based on the data obtained during the 15th Antarctic Expedition of China between November 1998 and February 1999, the paper discusses the water masses distributed on both sides of the Continental Water Boundary (CWB) as well as the spacial variability of the physical characteristics of the central location, the frontal width, the frontal strength, the vertical depth, and the vertical thickness for CWB. The above results are compared with the results from the data obtained during the 9th Antarctic Expedition of China between December 1992 and February 1993, and the temporal variability of those characteristics is discussed. In addition, the inhomogeneity of the kinematic characteristics and the patterns of the dynamic heights for those water masses located on both sides of CWB are illustrated. As it is pointed out in the paper, the trough in the dynamic height field is identified with the frontal location of CWB and the oceanic current shear. Furthermore, the dynamic reason for the upwelling of the circumpolar deep water can be understood by the explanation described in the paper. 展开更多
关键词 Pryze Bay oceanic front Continental Water Boundary VARIABILITY
下载PDF
上一页 1 2 8 下一页 到第
使用帮助 返回顶部