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Building Height Trends and Their Influencing Factors under China’s Rapid Urbanization:A Case Study of Guangzhou,1960–2017

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Chinese Geographical Science 2020年第6期30卷 993-1004页

作者： sun wu LI Tao School of Geography South China Normal UniversityGuangzhou 510631China Northwest Land and Resource Research Center Shaanxi Normal UniversityXi'an 710119China

Understanding the spatiotemporal patterns of three-dimensional urban forms,especially building height,can have important implications for improving urban air quality and mitigating the urban heat island effect by optimizing urban planning and management *** study investigated building height evolution and its influencing factors over approximately half a century(1960–2017)in Guangzhou,*** results indicated that the logarithmic declines in height,quantity,and area of urban buildings followed Zapf’s law,which restricts the three-dimensional shape of the urban *** urban building height decreased from the center to the periphery of the city and decreased with decreasing altitude and increasing distance from main *** characteristics constituted the three main spatial differentiation rules of building height in the central district of Guangzhou,and all exhibited a logarithmic decrease,which gradually strengthened over *** development of a double-layered height structure of low-rise and high-rise buildings between 1990 and 2017 was a notable manifestation of the increase in vertical urban height over *** three factors of city center,altitude,and accessibility,which represent centrality,low relief,proximity to water,and proximity to road networks,highlighted the roles of traffic accessibility and commercial attraction in building height *** importance of location macroscopically depends on the combined effect of the geographical pattern,urban planning,and market forces of cities located on a plain near hill or by a *** principle of profit orientation restricted spatiotemporal building height patterns.

关键词： building height urban form altitude road formative mechanism Guangzhou,China

VARIABILITY SETS AND HAMILTON SEQUENCES

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Chinese Annals of Mathematics,Series B 2005年第4期26卷 543-550页

作者： sun NA wu SHENGJIAN Key Laboratory of Pure and Applied Mathematics School of Mathematical Sciences Peking University Beijing 100871 China.

This paper studies extremal quasiconformal mappings. Some properties of the variability set are obtained and the Hamilton sequences which are induced by point shift differentials are also discussed.

关键词： Quasiconformal mapping Point shift differentials Hamilton sequence Extremal mapping

Neutronic analysis of deuteron-driven spallation target

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Nuclear Science and Techniques 2021年第9期32卷 52-60页

作者： Wei-Wei Qiu wu sun Jun Su Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China

Deuteron-driven spallation targets have garnered attention recently because they can provide high-energy neutrons to transmute long-lifetime fission *** this study,the Geant4 toolkit was used to simulate the inter-action between a deuteron beam at 500 MeV and a com-posite target composed of alternating lead-bismuth eutectic(LBE)and *** water was used because it may be employed as a target *** energy spectrum,neu-tron yield,average energy,and total energy of the emitted neutrons were calculated for different thicknesses and thickness ratios between the LBE and *** a constant target thickness,the neutron yield increases with an increasing thickness ratio of LBE to H 2 O,while the aver-age energy of the emitted neutrons decreases with an increasing in the aforementioned thickness *** two aspects support the use of a pure target,either LBE or ***,with an increasing LBE-to-H 2 O thickness ratio,the total energy of the emitted neutrons increases and then *** result supports the addition of water into the LBE *** angular distributions of the emitted neutrons show that the rear of the target is suit-able for loading nuclear waste containing minor actinides and long-lifetime fission products.

关键词： Long-lived nuclear waste product Accelerator-driven sub-critical system Deuteron-induced spallation target Neutron spectrum

Boundary Dilatation and Degenerating Hamilton Sequences

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Acta Mathematica Sinica,English Series 2006年第1期22卷 139-142页

作者： Na sun Sheng Jian wu LMAM and School of Mathematical Sciences Peking University Beijing 100871 P. R. China

In this paper, we study the boundary dilatation of quasiconformal mappings in the unit disc. By using Strebel mapping by heights theory we show that a degenerating Hamilton sequence is determined by a quasisymmetric f... 详细信息

关键词： Quasiconformal mapping Boundary dilatation Degenerating Hamilton sequence

Symplectic integrators with potential derivatives to third order

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Research in Astronomy and Astrophysics 2011年第3期11卷 353-368页

作者： Wei sun Xin wu Guo-Qing Huang Institute of Astronomy ＆ Department of Physics Nanchang University Nanchang 330031 China

An operator associated with third-order potential derivatives and a force gradient operator corresponding to second-order potential derivatives are used together to design a number of new fourth-order explicit symplectic integrators for the natural splitting of a Hamiltonian into both the kinetic energy with a quadratic form of momenta and the potential energy as a function of position *** simulations show that some new optimal symplectic algorithms are much better than their non-optimal counterparts in terms of accuracy of energy and position calculations.

关键词： celestial mechanics—methods:numerical

Analysis of subscription characteristics and user mobility in different types of MMORPGs

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The Journal of China Universities of Posts and Telecommunications 2009年第6期16卷 121-128页

作者： PENG Hui sun Yan-li wu Hong School of Economics and Management Beijing University of Posts and Telecommunications Beijing 100876 China

Massively multiplayer online role-playing game（MMORPG） is one of the fastest-growing segments of the online game *** subscription refers to game accounts logged in during a certain period of *** user mobility explains the dynamics of subscriber size *** article explores the subscription characteristics and user mobility in different types of *** is found that subscription characteristics in different types of MMORPGs are marked by *** one hand,the curve of competition-based game subscription is linear,and the stability period is short,therefore it is necessary for the game operators to introduce new versions *** the other hand,the gradient rate of subscription in the community-based game is slow at first and then fast,and the stability period is long,hence it will take the game operator a long cycle to launch a new *** difference of subscription curve is caused by the fact that user mobility in competition-based game is higher than in the community-based game,as attractiveness of community-based game can maintain a longer period due to network *** purpose of the study is to help the game operator to understand the development stage and features of the game and to make effective decisions to attract more players.

关键词： virtual reality online game subscription characteristics user mobility subscription curve life cycle MMORPG

Cycle Time Analysis for Wafer Revisiting Process in Scheduling of Single-arm Cluster Tools

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International Journal of Automation and computing 2011年第4期8卷 437-444页

作者： Yu-Xi sun Nai-Qi wu School of Mechatronics Engineering Guangdong University of Technology Guangzhou 510006 PRC

Some wafer fabrication processes performed by cluster tools require revisiting. With wafer revisiting, a cluster tool is very difficult to be scheduled due to a large number of possible schedules for the revisiting process. Atomic layer deposition （ALD） is a typical process with wafer revisiting that should be performed by cluster tools. This paper discusses the scheduling problem of single-arm cluster tools for the ALD process. In scheduling such a system, the most difficult part is to schedule the revisiting process such that the cycle time is minimized. Thus, this paper studies the revisiting process of ALD with revisiting times k = 3, 4, and 5, and analytical expressions are obtained to calculate the cycle time for the k possible schedules. Then, the schedule with the minimal cycle time is the optimal one. In this way, the scheduling problem of such a revisiting process becomes very simple and this is a significant improvement in scheduling cluster tools with wafer revisiting. Illustrative example is presented to show the application of the proposed method.

关键词： Scheduling semiconductor manufacturing cluster tools Petri net automated manufacturing systems.

Spatial variability of summertime aragonite saturation states and its influencing factor in the Bering Sea

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Advances in Climate Change Research 2021年第4期12卷 508-516页

作者： sun Heng GAO Zhong-Yong ZHAO De-Rong sun Xiu-wu CHEN Li-Qi Key Laboratory of Global Change and Marine-Atmospheric Chemistry(GCMAC)of Ministry of Natural Resources(MNR) Third Institute of Oceanography(TIO)MNRXiamen361005China

The Bering sea is susceptible to ocean acidification driven by both human activities(anthropogenic CO_(2))and distinctive natural *** assess the situation of ocean acidification,we investigated the spatial variability of aragonite saturation states(ΩAr)in July 2010 during the 4th Chinese National Arctic Research Expedition(CHINARE).The surface waters were all oversaturated with respect to aragonite(ΩAr>1)due to high biological removal,andΩAr ranged from 1.43 to *** relatively lowΩAr values were found in the western Bering Strait and eastern nearshore region of the Bering Sea Shelf,which were associated with the upwelling and riverine input,*** the subsurface,theΩAr decreased to generally low saturation states and were observed to be strongly undersaturated(ΩAr<1)in the bottom waters with a lowest value of 0.45,which might be caused by ***,unlike prior studies,the lowΩAr values in the shallow nearshore region were still above the saturation horizon throughout the water column,which were probably counteracted by high local primary *** the context of climate change and increasing anthropogenic CO_(2)absorption,the suppression and undersaturation ofΩAr in the Bering Sea are not only attributed to the natural processes but also the accumulation of anthropogenic CO_(2).

关键词： Bering sea Ocean acidification Aragonite saturation states Spatial variability Controls

Preparation of Fe-Based Bulk Amorphous Materials and Its Application to Sensors

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Journal of Rare Earths 2004年第z1期22卷 90-92页

作者： sun Xiaohua wu Jinbin Zhao Zengqi Zhao Jun sun Guangjie Liu Changsheng School of Materials &Metallurgy Northeastern UniversityShenyang 110004 China Baotou Rare Earth Research Institute Baotou 014010 China Baotou Rare Earth Research Institute Baotou 014010 China Baotou Rare Earth Research Institute Baotou 014010 China Baotou Rare Earth Research Institute Baotou 014010 China Baotou Rare Earth Research Institute Baotou 014010 China School of Materials &MetallurgyNortheastern UniversityShenyang 110004 China

The study of recent years found that big bulk amorphous alloys were formed for some multi-element compositions at rapid cooling speed such as Zr-, La-, Fe-, Mg-based alloys with wide undercooled liquid phase field and high trend of forming glass.( ATx = crystallization temperature Tx - glass transformation temperature Tg) Bulk amorphous copper mold upper suction casting with minus pressure while some new technical processes and adding new elements such as Co, Nb, Ca, *** used to improve magnetic properties and other performances of the *** results show that Fe-based bulk amorphous alloys have low coercive force and high permeability, which are successfully applied to magnetoelectric sensors with temperature ranges between -45 ℃ and 150 ℃ by special design of magnetic circuits.

关键词： bulk amorphous glass transformation ability suction casting of minus pressure sensor