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    题名 作者 年代 出处 被引量
1Why Lake Taihu continues to be plagued with cyanobacterial blooms through 10 years(2007–2017) efforts显示文摘With the expansion of urban, industry, and agriculture after World War II, eutrophication firstly emerged as a major water quality threat in small water bodies [1]. As the increasing magnitudes and scales of nutrient pollution and habitat alteration, many of the world's large lakes exhibit symptoms of eutrophication, e.g., toxic cyanobacterial blooms, deoxygenation, and habitat loss.Boqiang Qin Hans W.Paerl Justin D.Brookes Jianguo Liu Erik Jeppesen Guangwei Zhu Yunlin Zhang Hai Xu Kun Shi Jianming Deng 2019Science Bulletin2019,64,6:50
2A New Potential Function With Many-Atom Interactions in Solid显示文摘Based on the many-atom interaction model and valence bond theory of metals, a new potential function for the interaction among atoms in solid is proposed in the present work. Because the reduced bond length is taken as variable, the new potential function can be simplified to have the form analogous to the Lennard-Jones potential. Accoroding to Debye model, a series of equations for calculating various elasticities and constants K and Q in Gruneisen equation have been derived from the new potential function. The application of the new potential function to Ni, Cu and five alkli metals shows that these equations are correct.谢佑卿 1993Science China Mathematics1993,36,1:27
3DEVELOPMENT OF INCONEL~ ALLOY 783,A LOW THERMAL EXPANSION,CRACK GROWTH RESISTANT SUPERALLOY显示文摘DEVELOPMENTOFINCONEL~ALLOY783,ALOWTHERMALEXPANSION,CRACKGROWTHRESISTANTSUPERALLOYJ.H.Thndermann(IncoAlloysInternational,Inc....J.H.Thndermann(Inco Alloys International, Inc., Huntington, WV 25705, USA ) 1996Acta Metallurgica Sinica(English Letters)1996,9,6:23
4Review of metal matrix composites with high thermal conductivity for thermal management applicationsXuan-hui QU Lin ZHANG Mao WU Shu-bin REN 2011Progress in Natural Science:Materials International2011,21,3:22
5基于时变波动率的50ETF参数欧式期权定价显示文摘以上海证券交易所的首个股票期权品种50ETF为例,首先以时变波动率对经典BlackScholes期权定价公式常数波动率假设修正,然后基于正态分布、广义学生t分布和融入高阶矩的Edgeworth expansion渐近分布构建三种参数期权定价模型,最后采用参数显著性检验(Significance testing)、定价误差(Mispricing)、预测偏差(Forecastability)、对冲误差(Hedging errors)和波动率偏离修正(Volatility skew correction)5种严谨系统的评价标准,实证对比了在3种参数期权定价模型下的定价精度。研究结果表明:在时变波动率下,基于广义学生t分布和Edgeworth expansion渐近分布相比于正态分布显著提高了参数期权定价模型的定价精度。论文的研究成果为投资商和监管者提供了相对更为精确的期权定价模型。同时在相对更为准确的定价方法下,进一步利于50ETF期权在我国金融市场发挥价格发现和风险管理的作用。杨兴林 王鹏 2018数理统计与管理2018,37,1:17
6中国城市群形成发育与空间拓展的基本规律(英文)显示文摘Urban agglomerations are formed when a country is in the advanced stages of industrialization and urbanization. They are highly integrated groups of cities that form and develop through a natural, gradual process as the relationship between them changes from one of competition to assimilation following law of natural development. China is currently in a new stage of transitional development characterized by its New-Type Urbanization Plan. It has entered a new era in which it is a global leader in urban agglomeration development, and China’s research and development models are being imitated and adopted by countries around the world. This paper adopts a theoretical approach to propose the basic law governing the formation, development and expansion of urban agglomerations. This includes the stage-based formation and development law, multi-scale intensive-use transmission law,crystal-structure spatial composition law, egg-shaped expansion evolution law,'saplings-to-forest' natural growth law, and sustainable development incremental increase law.Guided by these law, China has created a hierarchical organizational configuration for optimizing the spatial structure of its urban agglomerations. It has also formulated urban agglomeration development plans and proposed research-based measures to resolve problems specific to urban agglomerations and to promote their sustainable development. The law governing the formation, development and expansion of urban agglomerations play an important role in guiding their development in China and will play a greater role in the future.方创琳 2019Journal of Geographical Sciences2019,29,10:16
7Progress in Semi-arid Climate Change Studies in China显示文摘This article reviews recent progress in semi-arid climate change research in China.Results indicate that the areas of semiarid regions have increased rapidly during recent years in China,with an increase of 33%during 1994-2008 compared to 1948-62.Studies have found that the expansion rate of semi-arid areas over China is nearly 10 times higher than that of arid and sub-humid areas,and is mainly transformed from sub-humid/humid regions.Meanwhile,the greatest warming during the past 100 years has been observed over semi-arid regions in China,and mainly induced by radiatively forced processes.The intensity of the regional temperature response over semi-arid regions has been amplified by land-atmosphere interactions and human activities.The decadal climate variation in semi-arid regions is modulated by oceanic oscillations,which induce land-sea and north-south thermal contrasts and affect the intensities of westerlies,planetary waves and blocking frequencies.In addition,the drier climates in semi-arid regions across China are also associated with the weakened East Asian summer monsoon in recent years.Moreover,dust aerosols in semi-arid regions may have altered precipitation by affecting the local energy and hydrological cycles.Finally,semi-arid regions in China are projected to continuously expand in the 21st century,which will increase the risk of desertification in the near future.Jianping HUANG Jieru MA Xiaodan GUAN Yue LI Yongli HE 2019Advances in Atmospheric Sciences2019,36,9:15
8Steps to consider in the approach and management of critically ill patient with spontaneous intracerebral hemorrhage显示文摘Spontaneous intracerebral hemorrhage is a type of stroke associated with poor outcomes. Mortality is elevated, especially in the acute phase. From a pathophysiological point of view the bleeding must traverse different stages dominated by the possibility of re-bleeding, edema, intracranial hypertension, inflammation and neurotoxicity due to blood degradation products, mainly hemoglobin and thrombin. Neurological deterioration and death are common in early hours, so it is a true neurologicalneurosurgical emergency. Time is brain so that action should be taken fast and accurately. The most significant prognostic factors are level of consciousness, location, volume and ventricular extension of the bleeding. Nihilism and early withdrawal of active therapy undoubtedly influence the final result. Although there are no proven therapeutic measures, treatment should be individualized and guided preferably by pathophysiology. The multidisciplinary teamwork is essential. Results of recently completed studies have birth to promising new strategies. For correct management it's important to establish an orderly and systematic strategy based on clinical stabilization, evaluation and establishment of prognosis, avoiding secondary insults and adoption of specific individualized therapies, including hemostatic therapy and intensive control of elevated blood pressure. Uncertainty continues regarding the role of surgery.Daniel Agustin Godoy Gustavo Rene Pi?ero Patricia Koller Luca Masotti Mario Di Napoli 2015World Journal of Critical Care Medicine2015,4,3:14
9High entropy(Yb0.25Y0.25Lu0.25Er0.25)2SiO5 with strong anisotropy in thermal expansion显示文摘A novel high entropy(HE) rare earth monosilicate(Yb0.25Y0.25Lu0.25Er0.252 SiO5 was synthesized by solid-state reaction method.X-ray diffraction and scanning electron microscopy analysis indicate that a single solid solution is formed with homogeneous distribution of rare-earth elements.HE(Yb0.25Y0.25Lu0.255 Er0.252 SiO5 exhibits excellent phase stability and anisotropy in thermal expansion.The coefficients of thermal expansion(CTEs) in three crystallographic directions are:αa=(2.57±0.07)×10^-6 K^-1,αb=(8.07±0.13)×10^-6 K^-1,αc=(9.98±0.10)×10^-6 K^-1.The strong anisotropy in thermal expansion is favorable in minimizing the coating/substrate mismatch if preferred orientation of HE(Yb0.25Y0.25Lu0.25Er0.252 SiO5 is controlled on either metal or ceramic substrate.Heng Chen Huimin Xiang Fu-Zhi Dai Jiachen Liu Yanchun Zhou 2020Journal of Materials Science & Technology2020,36,1:14
10Adaptive event-triggered control for a class of nonlinear systems with periodic disturbances显示文摘This paper investigates the adaptive event-triggered control problem for a class of nonlinear systems subject to periodic disturbances. To reduce the communication burden, a reliable relative threshold strategy is proposed. Fourier series expansion and radial basis function neural network are combined into a function approximator to model suitable time-varying disturbed function of known periods in strict-feedback systems. By combining the Lyapunov stability theory and the backstepping technique, the proposed adaptive control approach ensures that all the signals in the closed-loop system are bounded, and the tracking error can be regulated to a compact set around zero in finite time. Finally, simulation results are presented to verify the effectiveness of the theoretical results.Hui MA Hongyi LI Renquan LU Tingwen HUANG 2020Science China(Information Sciences)2020,63,5:14
11A Regulatory Module Controlling CA-Mediated Endosperm Cell Expansion Is Critical for Seed Germination in Arabidopsis显示文摘A key component of seed germination is the interplay of mechanical forces governing embryo growth and the surrounding restraining endosperm tissue.Endosperm cell separation is therefore thought to play a critical role in the control of this developmental transition.Here we demonstrate that in Arabidopsis thaliana seeds,endosperm cell expansion is a key component of germination.Endosperm cells expand to accommodate embryo growth prior to germination.We show that this is an actively regulated process supported by spatiotemporal control of the cell expansion gene EXPANSIN 2 (EXPA2).The NAC transcription factors NAC25 and NACIL were identified as upstream regulators of EXPA2 expression,gibbereliinmediated endosperm expansion,and seed germination.The DELLA protein RGL2 repressed activation of the EXPA2 promoter by NAC25/NACIL.Taken together,our findings uncover a key role of the GA/ DELLA-NAC25/NACIL-EXPA2 network in regulating endosperm cell expansion to control the seed-toseedling transition.Rocio Sanchez-Montesino Laura Bouza-Morcillo Julietta Marquez Melania Ghita Salva Duran-Nebreda Luis Gomez Michael J.Holdsworth George Bassel Luis Onate-Sanchez 2019Molecular Plant2019,12,1:11
12Spatiotemporal characteristics of the expansion of an urban agglomeration and its effect on the eco-environment: Case study on the northern slope of the Tianshan Mountains显示文摘Urban agglomerations, which are highly integrated urban groups, form during the advanced stages of industrialization and urban development. The urban agglomeration on the northern slope of the Tianshan Mountains is one of the 19 urban agglomerations promoted by China’s 13th Five-Year Plan and a key area of urbanization in Xinjiang. Based on remote sensing data, we analyzed the expansion of construction land in the urban agglomeration on the northern slope of the Tianshan Mountains and its effect on ecological value in 1980–2015. The results show that the expansion of construction land significantly affected ecological value in the study area over the past 35 years. Among land use types, grassland was the dominant contributor to changes in ecological value;its contribution rate reached 66.27% with an interannual variation of only 5%. The contribution rate of urban and rural residential land along with industrial and mining lands was very low(0.82%), while the interannual variation was large(86%). The area of construction land in the urban agglomeration expanded from 1,067 to 2,586 km^2, and the conversions of different land use types had different effects on ecological value. Among land use types, the conversions of lowcoverage grassland and dry land made the largest contributions to changes in ecological value. During the study period, a total of 1,685 km^2 of ecological land, 69.91% of which belonged to cultivated land and grassland, was converted into construction land.A total area of 1,082 km^2 of dry land and low-coverage grassland was converted into construction land, accounting for 64.21% of the total ecological land that was converted into construction land. In 2000–2015, the area of urban construction land increased significantly along with the proportion of unused land, including gobi(172 km^2), bare land(65 km^2), and salt-affected land(65 km^2), being converted into construction land. In contrast, the area of construction land that was converted into ecological land was less than 166 km^2. The areas with the largest expansions of construction land were concentrated in Urumqi, Karamay,and Changji, where the areas of construction land increased by 399, 186, and 126 km^2, respectively. The areas with the most rapid expansions in construction land were concentrated in Kuytun, Toksun, and Usu. The environmental effects of construction land expansion and land use change were more positive in the late stage of urban agglomeration(2000–2015) compared to in the early stage(1980–2000). Kuytun City, Shihezi City, and Wujiaqu City showed large changes in ecological value caused by the expansion of construction land, whereas the changes in ecological value in the 14 other cities were relatively small, and the expansion of construction land slowed in 2000–2015 compared to in 1980–2000. In the future, further development of the urban agglomeration on the northern slope of the Tianshan Mountains should fully consider the sensitivity and carrying capacity of the vulnerable ecological environment in this area. Population growth and industrial development in the urban agglomeration should be controlled based on the available water resources and ecological capacity to reduce the pressure on the environment and ensure sustainable development.Chuanglin FANG Qian GAO Xiaolei ZHANG Weiguo CHENG 2019Science China Earth Sciences2019,62,9:11
13A UNIVERSAL ANALYTIC POTENTIAL-ENERGY FUNCTION BASED ON A PHASE FACTOR显示文摘Using a field equation with a phase factor, a universal analytic potential-energy function applied to the interactions between diatoms or molecules is derived, and five kinds of potential curves of common shapes are obtained adjusting the phase factors. The linear thermal expansion coefficients and Young’s moduli of eleven kinds of face-centered cubic (fcc) metals - Al, Cu, Ag, etc. are calculated using the potential-energy function; the computational results are quite consistent with experimental values. Moreover, an analytic relation between the linear thermal expansion coefficients and Young’s moduli of fcc metals is given using the potential-energy function. Finally, the force constants of fifty-five kinds of diatomic moleculars with low excitation state are computed using this theory, and they are quite consistent with RKR (Rydberg-Klein-Rees) experimental values.C.F. Yu* Deptartment of Physics, College of Science, Xi’an Polytechnic University, Xi’an 710048, China K. Yan Xi’an Modern Nonlinear Science Applying Institute, Xi’an 710061, China D.Z. Liu Section 602, Second Artillery Institute of Engineering, Xi’an 710025, China 2006Acta Metallurgica Sinica(English Letters)2006,19,6:11
14Thermoelastic properties of sandwich materials with pin-reinforced foam cores显示文摘Pin-reinforced foam is a novel type of sandwich core materials formed by inserting pins(trusses) into a foam matrix to create a truss-like network reinforced foam core.Upon loading,the pins deform predominantly by local stretching whilst the deformation of foam is governed by local bending.This paper presents a theoretical study on the thermoelasticity of pin-reinforced foam sandwich cores.To calculate the effective thermoelastic properties of pin-reinforced foam cores,the energy-based homogenization approach is employed to develop a micromechanics-based model,calibrated by the existing experimental data.It is found that the stiffness of the sandwich core is mainly governed by pin reinforcements:the foam matrix contributes little to sandwich stiffness.Compared with traditional foam cores without pin reinforcements,the changes in inplane thermal expansion coefficients are not vigorous as a result of pin reinforcements,while the through-thickness thermal expansion coefficient changes significantly.It is also demonstrated that it is possible to design materials with zero or negative thermal expansion coefficients under such a context.LU TianJian1,LIU Tao2,3 & DENG ZiChen2,4 1 MOE Key Laboratory of Strength and Vibration,School of Aerospace,Xi’an Jiaotong University,Xi’an 710049,China 2 Department of Engineering Mechanics,Northwestern Polytechnical University,Xi’an 710072,China 3 Department of Engineering,University of Cambridge,Cambridge CB2 1PZ,UK 4 State Key Laboratory of Structural Analysis of Industrial Equipment,Dalian University of Technology,Dalian 116024,China 2008Science China(Technological Sciences)2008,51,12:10
15Air/CO2 cooling garment: Description and benefits of use for subjects exposed to a hot and humid climate during physical activities显示文摘The severity of the hot and humid conditions to which miners are exposed increases as the depth of the work site increases.This can cause heat stress that can greatly affect the health and safety of workers.To resolve this,a cooling garment has been developed that uses an atmospheric discharge of liquid CO2 to create a cool microclimate with an average temperature of 12.5(±0.4)℃ beneath the garment.To evaluate the garment's cooling efficiency,19 male subjects participated in an experimental procedure.The two modes,cooling on and off,were compared.Significant physiological differences were found between the two modes after minute 27(p<0.05)until the end of the recovery phase for the heart rate(maximum difference of 10 beats per minute)and the internal body temperature(maximum difference of 0.33℃).It was found that the modes also affected the subjects'perceptions.The ON-mode was associated with better well-being and thermal comfort,and reduced humidity sensation.Perceptions of exertion were lower in the ON-mode condition from minute 2.The findings provide strong evidence of the ability of this cooling garment to reduce heat stress in hot and humid conditions similar to those encountered in deep mines.Chady Al Sayed Ludwig Vinches Olivier Dupuy Wafa Douzi Benoit Dugue Stephane Halle 2019International Journal of Mining Science and Technology2019,29,6:10
16A STUDY ON THE VARIATION OF DROUGHT PERIODS OCCURRING IN NORTHWEST CHINA AND OTHER AFRICA-ASIA CONTINENTAL REGIONS显示文摘Characteristics of the drought periods which occurred in North Africa,Middle East,Middle Asiaand Northwest China were studied based on the analysis of rainfall data from 1870—1990.It is foundthat the drought periods first started in North Africa and expanded eastward to Northwest Chinathrough Middle East and Middle Asia in about 27.5 years.And then a new teleconnection pattern of30—50 day low-frequency oscillation which is associated with the droughts over the Africa-Asia Con-tinent was discovered.Finally,a hypothesis is proposed based on the statistical results that the east-ward expansion of drought periods may be caused by the occurrence of giant earthquakes(Ms>6.0)which have a tendency to shift eastward from North Africa to Northwest China in about 27.75 years.孙国武 叶谦 1996Acta meteorologica Sinica1996,10,4:9
17Damage localization under ambient vibration using changes in flexibility显示文摘In recent years, Structural Health Monitoring (SHM) has emerged as a new research area in civil engineering. Mostexisting health monitoring methodologies require direct measurement of input excitation for implementation. However, in manycases, there is no easy way to measure these inputs - or alternatively to externally excite the structure. Therefore, SHM methodsbased on ambient vibration have become important in civil engineering. In this paper, an approach is proposed based on the DamageLocation Vector (DLV) method to handle the ambient vibration case. Here, this flexibility-matrix-based damage localization methodis combined with a modal expansion technique to eliminate the need to measure the input excitation. As a by-product of thisapproach, in addition to determining the location of the damage, an estimate of the damage extent also can be determined. Finally, anumerical example analyzing a truss structure with limited sensors and noisy measurement is provided to verify the efficacy of theproposed approach.高勇 苏磐石 2002Earthquake Engineering and Engineering Vibration2002,1,1:9
18基于大数据的全球城市扩展与土地覆盖动态遥感制图显示文摘Humans deeply influence the urbanizing of earth’s surface system in an exacerbating manner across space and time[1].Around the globe,urban land-use/cover changes reflect the intensities of human activities and land shifts from nature or semi-nature lands to man-made–dominated surfaces[2].匡文慧 杜国明 陆灯盛 窦银银 李孝永 张澍 迟文锋 董金玮 陈广生 尹哲睿 潘涛 Rafiq Hamdi 侯亚丽 陈春阳 李晗 苗晨 2021Science Bulletin2021,66,4:8
19A MUCLTI-PARAMETER SPLITTING EXTRAPOLATION AND A PARALLEL ALGORITHM显示文摘The finite element solutions of elliptic equations are shown to have a multiparameter asymptotic error expansion. Based on this expansion and a multi-parametersplitting extrapolation technique, a parallel algorithm for solving multi-dimensional equations with high order accuracy is introduced.ZHOU Aihui(Institute of Systems Science, Academia Sinica, Beijing 100080, China)Liem Chin-ho Shih Tsi-min(Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong)LU Tao(Institute of Chengdu Computer Application, Academia Sinica, Ch 1997Systems Science and Mathematical Sciences1997,10,3:8
20Electronic Structure and Properties of Cu Metal~*显示文摘Department of Materials Science and Engineering, Central South University of Technology, Changsha 410083XIE You-Qing ZHANG Xiao-Dong ZHAO Li-Ying and MA Xiu-Lin (Department of Materials Science and Engineering, Central South University of Technology, Changsha 410083, PRC) 1993Science China Mathematics1993,36,4:7
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