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海南密花石斛资源现状调查及居群表型多样性研究

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热带林业 2024年第2期52卷 73-76,72页

作者：钟国和王景飞蔡嘉慧黄赛张浪任军方海南省林业科学研究院(海南省红树林研究院) 海南海口571100 海南省农业科学院热带园艺研究所海南海口570100 海南省农业科学院三亚研究院海南三亚572025

通过查阅文献、实地踏查等方法对海南密花石斛种质资源进行调查,以收集到的10个居群材料为研究对象,利用变异系数、主成分分析、相关分析、聚类分析等方法,对获取的表型性状进行遗传多样性分析。结果显示,12个表型性状的变异系数均值在4... 详细信息

通过查阅文献、实地踏查等方法对海南密花石斛种质资源进行调查,以收集到的10个居群材料为研究对象,利用变异系数、主成分分析、相关分析、聚类分析等方法,对获取的表型性状进行遗传多样性分析。结果显示,12个表型性状的变异系数均值在4.5%~25%之间,在居群间大于居群内变异;而主成分分析结果显示,其变异主要来自花序长、茎粗和唇瓣长;Pearson相关分析则表明小花数同唇瓣长相关性最大,为0.8087;根据Q型聚类分析结果,在欧式距离为20处,将供试材料分为2大类。该研究结果可在密花石斛品种选育和保护利用时提供数据参考。

关键词：海南岛密花石斛保护利用居群表型多样性

On Ohtsuki's Invariants of Integral Homology 3-Spheres

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Acta Mathematica Sinica,English Series 1999年第3期15卷 293-316页

作者： Xiaosong Lin Zhenghan Wang Department of Mathematics, University of california, Riverside, ca 92521, U. S. A.Department of Mathematics, Indiana University, Bloomington, IN 47405, U. S. A. Department of Mathematics, University of california, La Jolla, ca 92093, U. S. A. Department of Mathematics University of California Riverside U. S. A. Department of Mathematics Indiana University Bloomington U. S. A. Department of Mathematics University of California La Jolla U. S. A.

We provide some more explicit formulae to facilitate the computation of Ohtsuki’s rational invariants λn of integral homology 3-spheres extracted from Reshetikhin-Turaev SU（2） quantum invari- ants. Several interesting consequences will follow from our computation of λ2. One of them says that λ2 is always an integer divisible by 3. It seems interesting to compare this result with the fact shown by Murakami that λ1 is 6 times the casson invariant. Other consequences include some general criteria for distinguishing homology 3-spheres obtained from surgery on knots by using the Jones polynomial.

关键词： Finite type invariant Fermat limit Homology sphere Surgery formula

Microstructure and Mechanical Behaviour of Proton-and Ion-irradiated Ll_2 Intermetallic Compounds

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Journal of Materials Science & Technology 1994年第4期10卷 235-245页

作者： F. C. Chen and A .J.Ardell (Dept. of Materials Science and Engineering, University of california, Los Angeles, ca 90024-1595, USA) Univ of california Los Angeles United States

The results of mechanical testing and transmission electron microscopy on the ordered intermetallic Ll2 compounds1Zr3Al, Ni3Al, Ni3Si and Ni3Ge after irradiation with protons or heavy ions at high or low tem peratu re are presented and discussed. Using a minjaturjzed disk-bend test. it was found that proton irradiation of Zr3Al. Ni3Al and Ni3Si raises their yield strength :a single test of Ni3Ge shows no effect on the fracture stress of this brittle intermetallic The Vickers microhardness of all four alloys is raised by proton irradiation. The irradiations cause all the alloys to disorder. the extent of which is dependent on irradiation temperature Microstructural defects are produced by the irradiations Some exhibit strain-field contrast under dynamic two-beam diffracting conditions. Other distinct defect clusters are imaged only in dark-field using su perlattice reflections, These latter defects are discussed in the context of current arnorphization models. The strength increase of Zr3Al, Ni3Al and Ni3Si is attributed to a combination of disordering and strengthening from defects. The lack of an effect of irradiation on the fracture stress of Ni3Ge. in which voids were observed, requires further experiments

关键词： Ni Si Zr Microstructure and Mechanical Behaviour of Proton-and Ion-irradiated Ll2 Intermetallic Compounds Figure

Environmental Occurrence of Selenium in Waters and Related Health Significance

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Biomedical and Environmental Sciences 1997年第2期10卷 292-299页

作者： JANE L. VALENTINE(School of Public Health, University of calIfornia at Los Angeles, Los Angeles, ca 90024, USA) School of Public Health University of California at Los Angeles 90024 USA.

Appreciable amounts of selenium in spring and well waters can be found due to geological occurrence. Concentrations of as much as 400 9000 μg/l have been reported in U. S. *** levels are 8 to 180 times the current EPA drinking water standard and approximate dietary exposures of 4900μg in selenosis regions of China. Reviews of health significance of the elevated drinking water exposures to U. S. populations revealed elevated concentrations of selenium in urine and blood. A decrease in glutathione peroxidase activity in such instances was noted. However noticeable symptoms and signs seem absent in studies reviewed. A comparison of intake levels (diet or drinking water) to urinary excretion for residents of China and the U. S. produced a correlation coefficient, r = 0. 82 (P < 0. 01 ) for the three research studies available

关键词： In Am Environmental Occurrence of Selenium in Waters and Related Health Significance

STATE POLICY AND URBAN SYSTEMS :THE caSE OF CHINA

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Journal of Geographical Sciences 1997年第1期7卷 1-10页

作者： YehuaWei DepartmentofGeography ,Universityofcalifornia LosAngeles LosAngeles,ca 90 0 2 4,USA

Thispaperusestherank sizemodelandtheexpansionmethodtoexaminethe changeofcity sizedistributioninChinafrom 1 95 2to 1 990 .Itrevealsthatafterashort periodofconcentration ,populationdeconcentrationamongcitieshasdominatedurban China .Thistrendhasevenbeenspeededupinthereformperiodsince 1 *** lishmentofalargeamountofnewcitieshaslargelycontributedtothetrendofdecreasing *** lishedcities,Chinesesystemofcitieswouldexperienceatrendofincreasedpopulation concentrationandpopulationintheupper rankcitiesgrewfasterthanthatinthelower rankcities.

关键词： urban systems urban policy rank -sizemodel expansion method China .

Next-generation lithography for 22 and 16 nm technology nodes and beyond

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Science China(Information Sciences) 2011年第5期54卷 959-979页

作者： WU Banqiu Applied Materials, Inc., Building 81, M/S 81311, 1285 Walsh Ave, Santa Clara, ca 95050, USA Applied Materials Inc. Santa Clara USA

In this paper, next-generation lithography (NGL) for the 22 and 16 nm technology nodes and beyond is reviewed. A broad range of topics, including history, technologies, critical challenges, and the most plausible candidates are discussed. The 22 and 16 nm technology nodes rely on NGL. NGLs have been extensively studied. Because of technological issues, the semiconductor industry has stopped pursuing several NGLs, such as X-ray proximity lithography, ion projection lithography, and scattering with angular limitation projection electron lithography. Currently, the primary candidate technologies are extreme ultraviolet lithography (EUVL), maskless lithography (ML2), and nanoimprint lithography (NIL), with EUVL being the leading candidate. Since EUVL was first proposed in 1988, many studies have been conducted. Currently, there is no "show stopper" for EUVL. Moreover, challenges are present in almost all aspects of EUVL technology. Almost all primary semiconductor manufacturing companies plan to implement commercial pre-production step-and-scan exposure tools in 2011. However, EUVL power at an intermediate focusing level has not yet met the volume manufacturing requirements. EUVL resists have been significantly improved recently, but there is still a critical need to meet requirements on resolution, line width roughness, and sensitivity. Creating a defect-free EUVL mask is another obstacle to the application of EUVL. ML2 and NIL, like EUVL, have also undergone significant progress recently, but throughput, defect control, and cost remain the critical impediments for practical application.

关键词： lithographic NGL XPL IPL NIL

Species Richness and Abundance of Bivalves and Gastropods in Mangrove Forests of casiguran, Aurora, Philippines

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Open Journal of Ecology 2020年第12期10卷 778-787页

作者： Maria Cristina B. cañada Research and Development Services Office Aurora State College of Technology Baler Aurora Philippines

The diversity and abundance of bivalves and gastropods were studied from April to July 2015. Two sampling stations, Tinib and Esteves, in casiguran, Aurora were selected based on the presence of mangrove forest, bivalves, gastropods, muddy substrate, and gleaners for the establishment of a transect line. Each station was laid with 100 meters transect line overlaid continuously with 2 m × 2 m quadrat along each transect. A total of 50 sampling units covering 0.02 ha area per sampling station were surveyed. The transect line recorded six species of bivalves distributed among five families and 12 species of gastropods belonging to eight families. Three species of bivalves and five species of gastropods were common to both sampling stations. However, Tinib station had most diverse species of bivalves (0.55) while Esteves station had most diverse species of gastropods (0.43). Both stations revealed Dendrostrea folium (43%) (bivalve) and Cerithidea cingulata (93%) (gastropods) as most frequently occurring species. Dendostrea folium also emerged as the densest (10,640 ind∙ha−1 and 6850 ind∙ha−1) and most abundant (58.52% and 77.84%) bivalve species. For gastropods, Terebralia sulcata (249,250 ind∙ha−1) was the densest and most abundant (96.97%) in Tinib while Terebralia palustris was the densest (747,050 ind∙ha−1) and most abundant (70.44%) in Esteves. Pooled results for bivalve species maintained Dendrostrea folium as the densest (8750 ind∙ha

Adaptive Agent-Based Modeling Framework for Collective Decision-Making in Crowd Building Evacuation

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Journal of Shanghai Jiaotong university(Science) 2021年第4期26卷 522-533页

作者： CHEN Feier ZHA0 Qiyuan ca0 Mingming CHEN Jiagi FU Guiguan State Key Laboratory of Ocean Engineering Key Laboratory of Marine Intelligent Equipment and System of Ministry of EducationShanghai Jiao Tong UniversityShanghai200240China Marautec Co. Ltd.Shanghai201206China Zhiyuan College Shanghai Jiao Tong UniversityShanghai200240China School of Mathematical Sciences Shanghai Jiao Tong UniversityShanghai200240China Institute of Fintech Shanghai University of Finance and EconomicsShanghai200433China

Crowd evacuation in different situations is an important topic in the research field of safety. This paper presents a hybrid model for heterogeneous pedestrian evacuation simulation. Our adaptive agent-based model (ABM) combines the strength of human crowd behavior description from classical social force models with discrete dynamics expression from cellular automaton models by extending the conception of floor field. Several important factors which may influence the results of decision-making of pedestrians are taken into consideration, such as the location of sign, the attraction of exit, and the interaction among pedestrians. To compare the effect of information on the pedestrians, we construct three decision-making mechanisms with different assumptions. To validate these three simulation models, we compare the numerical results from different perspectives with rational range in the case study where the Tampere Theater evacuation was carried out. The ABM framework is open for rules modification and could be applied to different building plans and has implication for architectural design of gates and signs in order to increase the evacuation efficiency.

关键词： adaptive agent-based model evacuation simulation emergency interaction heterogeneity

Upscaling conductivity and porosity in three-dimensional heterogeneous porous media

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Chinese Science Bulletin 2004年第22期49卷 2415-2423页

作者： ZHANG Yong Hydrologic Science,University of california,Davis,ca 95616,USA Desert Research Institute,2215 Raggio Parkway,Reno,NV 89512,USA Hydrologic Science University of California Davis CA 95616 United States Desert Research Institute 2215 Raggio Parkway Reno NV 89512 United States

An empirical formula is presented to upscale the conductivity of 3-dimensional heterogeneous porous me- dia, in which the distribution of local-scale conductivity is non-Gaussian with a high variance. The upscaled conductiv- ity is determined as a function of the volumetric proportion, the spatial connectivity and the statistical geometric length of high-permeable inclusions, and the arithmetic mean of con- ductivities of all hydrofacies. A systematic comparison to other traditional upscaling methods indicates that this em- pirical formula provides a better estimation of the equivalent conductivity. In the second part of this study, numerical ex- periments of solute migration reveal that porosity also needs to be upscaled to capture the transport of contaminants in a heterogeneous medium using an effective or upscaled homo- geneous medium. This is due to the tendency of contaminants to be preferrentially transported by 3-dimensional pathways composed of high-permeable materials in heterogeneous aquifer systems. The apparent difference between the actual transport velocity of contaminants and the upscaled velocity, based on the equivalent conductivity, forces upscaling of po- rosity. Further systematic analyses demonstrate that the up- scaled porosity follows a non-linear trend as the content of high-permeable sediments decreases. Resultant upscaled porosity, with values varying between 0.004 and 1.5, is be- yond the definition of the traditional porosity on the representative elementary volume (REV) scale. When the content of high-permeable materials is less than 30%, the upscaling of porosity is critical in the simulation of the contaminant transport in a heterogeneous medium using an upscaled, homogeneous counterpart.

关键词：标度方法传导率多孔性三维空间异类多孔介质多孔材料