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Asymmetric reversible structural switching of a diene coordination polymer promoted by UV-visible light

Science China Chemistry 2024年第2期67卷 536-541页

作者： Yong wang Qiaoqiao Zhang Yong-Yong Cao Qi Liu Brendan F.Abrahams Jian-ping Lang College of Chemistry Chemical Engineering and MaterialsSoochow UniversitySuzhou215123China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai200032China College of Biological Chemical Science and EngineeringJiaxing UniversityJiaxing314001China School of Chemistry University of MelbourneVictoria3010Australia

In natural and artificial systems,reversible reactions are commonly asymmetric with respect to the time scale and nature of the stimuli which drive the forward and backward *** applications for which switching behavior is required,it is desirable that the reversible reaction goes as close to symmetric as possible;however,such systems are ***,we report an example of ultraviolet(UV)-visible light-regulated asymmetric reversible structural switching involving a diene-based coordination polymer,CP1 and its monocyclobutane product,*** is possible to cycle at least ten times through a forward [2+2] photocycloaddition reaction and the reverse,photocleavage reaction.A single cycle can be completed within a few *** transformation is accompanied by fast and distinct fluorescence changes,arising from optimisation of the reaction *** functional theory calculations allow rationalisation of the asymmetric reversible transformation between CP1 and CP1a rather than between CP1 and its dicyclobutane product *** work provides a clear illustration of reversible structural switching which approaches symmetric behaviour with respect to reaction rate and *** insights gained from this work also assist in the design of fast,reversible switching materials.

关键词： asymmetrical reversible structural switching coordination polymer photocycloaddition UV-visible light-controlled fluorescence switching

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客户端独立的IP地理定位研究综述

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软件学报 2025年第1期36卷 321-340页

作者：林金磊李城龙宋光磊樊琳娜王之梁杨家海清华大学网络科学与网络空间研究院中关村实验室国防科技大学信息通信学院

准确、快速地获取IP地理定位信息对于各种网络应用而言至关重要. IP地理定位指将互联网实体的IP地址转换为其地理位置的技术.然而,互联网规模的迅速扩大和互联网应用的快速发展,给IP地理定位研究带来了巨大的挑战.首先,复杂的网络结构... 详细信息

准确、快速地获取IP地理定位信息对于各种网络应用而言至关重要. IP地理定位指将互联网实体的IP地址转换为其地理位置的技术.然而,互联网规模的迅速扩大和互联网应用的快速发展,给IP地理定位研究带来了巨大的挑战.首先,复杂的网络结构和网络环境导致IP定位技术的精确度远远无法满足实际的应用需求.其次,IP地理定位在各个领域的作用日益凸显,如何精准、高效、可靠地计算互联网主机的地理位置正在成为各行关注的焦点.因此,通过设备的IP地址对其进行地理定位以支撑复杂的上层应用尤为重要.自2001年以来,学术界和工业界围绕上述问题开展了大量的研究.系统地梳理客户端独立的IP地理定位方面的相关工作,系统地整理基于网络测量的IP地理定位研究分类方法.根据定位数据是否由主动测量产生,将相关研究分为主动的IP定位技术、被动的IP定位技术和主被动结合的IP定位技术.进一步,对每一类方法进行更细粒度的分类并分析其主要的优缺点.在此基础上,总结IP地理定位领域的最新进展和研究挑战,并展望其未来发展方向.

关键词：网络测量 IP地理定位地理定位地标

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A Simple yet Effective Framework for Active Learning to Rank

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Machine Intelligence Research 2024年第1期21卷 169-183页

作者： Qingzhong wang Haifang Li Haoyi Xiong Wen wang Jiang Bian Yu Lu Shuaiqiang wang Zhicong cheng Dejing Dou Dawei Yin Baidu Incorporated Beijing 100085China

While China has become the largest online market in the world with approximately 1 billion internet users,Baidu runs the world's largest Chinese search engine serving more than hundreds of millions of daily active users and responding to billions of queries per *** handle the diverse query requests from users at the web-scale,Baidu has made tremendous efforts in understanding users'queries,retrieving relevant content from a pool of trillions of webpages,and ranking the most relevant webpages on the top of the *** the components used in Baidu search,learning to rank(LTR)plays a critical role and we need to timely label an extremely large number of queries together with relevant webpages to train and update the online LTR *** reduce the costs and time con-sumption of query/webpage labelling,we study the problem of active learning to rank(active LTR)that selects unlabeled queries for an-notation and training in this ***,we first investigate the criterion-Ranking entropy(RE)characterizing the entropy of relevant webpages under a query produced by a sequence of online LTR models updated by different checkpoints,using a query-by-com-mittee(QBC)***,we explore a new criterion namely prediction variances(PV)that measures the variance of prediction res-ults for all relevant webpages under a *** empirical studies find that RE may favor low-frequency queries from the pool for la-belling while PV prioritizes high-frequency queries ***,we combine these two complementary criteria as the sample selection strategies for active *** experiments with comparisons to baseline algorithms show that the proposed approach could train LTR models to achieve higher discounted cumulative gain(i.e.,the relative improvement DCG4=1.38%)with the same budgeted labellingefforts.

关键词： Search information retrieval learning to rank active learning query by committee

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Combining cellular automata and Monte Carlo algorithm to simulate three-dimensional grain growth

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中国有色金属学会会刊：英文版 2006年第A02期16卷 104-106页

作者： wang Wei CHEN Ju-hua GUO Pei-quan ZHAO ping School of Mechanical Engineering Shandong University Ji＇nan 250061 China School of Mechanical Engineering Ji＇nan University Ji＇nan 250022 China

A 3-D simulation of grain growth was conducted by utilizing cellular automata (CA) and Monte Carlo (MC) algorithm. In the simulating procedure, the three-dimensional space is divided into a large number of 2-D isometric planes. Then, each of the planes is divided into identical square cells. Finally, the cellular automata and Monte Carlo algorithm are combined together to simulate the grain growth. Through an evolutionary simulation, the recrystallized microstructure, the grain growth rate and the grain size distribution are acceptably predicted. The simulation routine can be used to simulate the real physical-metallurgy processes and to predict quantitative dynamic information of the evolution of microstructure. Further more, the method is also useful for optimization of materials properties by controlling the microstructure evolution.

关键词：晶粒生长三维模拟细胞自动机蒙特卡洛算法显微结构

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Two comparable Ba-MOFs with similar linkers for enhanced CO_(2)capture and separation by introducing N-rich groups

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Rare Metals 2021年第2期40卷 499-504页

作者： Ying Zhao Jiao Liu Min-Le Han Guo-ping Yang Lu-Fang Ma Yao-Yu wang College of Chemistry and Chemical Engineering Henan Key Laboratory of Function-Oriented Porous MaterialsLuoyang Normal UniversityLuoyang471934China Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education Shaanxi Key Laboratory of Physico-Inorganic ChemistryCollege of Chemistry and Materials ScienceNorthwest UniversityXi’an710127China

Two new different metal-organic frameworks(MOFs)[Ba(L1)(H_(2)O)_(2)]_(n)·nH_(2)O(MOF 1)and[Ba(L2)(-n2 O)_(2)]_(n)·0.5 nDMF·0.5 nH_(2)O(MOF 2)were yielded by the assembly of oxygen-friendly Ba(Ⅱ)ions and two similar linkers,namely 2-(imidazol-1-yl)terephthalic acid(H_(2)L1)and 2-(1 H-1,2,4-triazol-1-yl)terephthalic acid(H_(2)L2).Single-crystal X-ray diffractions(XRD)indicate that MOF1 is a new three-dimensional(3 D)stacking dense network formed by the one-dimensional(1 D)rod-shaped chains and L1 linkers,whereas MOF 2 presents a 3 D nanotube porous framework with cylindrical tunnels based on the 1 D loop chains as the secondary building units(SBUs)by replacing the imidazole group in H_(2)L1 with the triazole group in H_(2)*** a result,MOF 2 has a higher density of active sites and Lewis acid sites in the porous surface of nanotube than MOF ***,the CO_(2)capture and separation capacity of MOF 2 is great higher than that of CH_(4)at298 K.

关键词： MOFs Similar linkers Secondary building units(SBUs) CO_(2)capture Isosteric heat

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Seeing measurements for the Guoshoujing Telescope (LAMOST) site with DIMM

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Research in Astronomy and Astrophysics 2010年第10期10卷 1061-1070页

作者： Li-Yong Liu Yong-Qiang Yao Yi-ping wang Jiang-Long Ma Bo-Liang He Hong-Shuai wang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

We present seeing measurements of the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope- LAMOST） site at Xinglong station during the period from 2007 March 12 to April 25. The measurements were carried out with the Differential Image Motion Monitor （DIMM）, and a total of 9259 data sets was obtained. The median seeing was measured to be 1.1″, with 25% being better than 0.8″and 75% better than 1.5″. The experiment shows that the DIMM exposure time has significant effects on the results of seeing measurements. An SBIG Polaris seeing monitor, which had been planned to be installed on the LAMOST site for long-term monitoring, was also employed during the DIMM observations. The results show that the SBIG seeing monitor is easily affected by gusty wind, resulting in larger seeing values. Considering the previous seeing measurements at Xinglong station over the last 15 yr, we conclude that an acceptable seeing condition at Xinglong station is around 1″-2″.

关键词： techniques atmospheric turbulence seeing -- instrumentation DIMM -- site testing LAMOST

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Synthesis of Polycrystalline Diamond Compact with Selenium:Discovery of a New Se–C Compound

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Chinese Physics Letters 2020年第5期37卷 102-105页

作者： Wen-Dan wang Ao Li Guo-Heng Xu Pei wang Yue-Gao Liu Li-ping wang School of Physical Science and Technology Southwest Jiaotong UniversitChengdu 610031 Materials Research Center Institute of Modern PhysicsChinese Acadermy of SciencesLanzhou 730000 Academy for Advanced Interdisciplinary Studies Southern University of Science and Technology(SUSTech)Shenzhen 518055 CAS Key Laboratory for Experimental Study under Deep-Sea Extreme Conditions Institute of Deep-Sea Science and EngineeringChinese Academy of SciencesSanya 572000

Sintering of polycrystalline diamond with selenium was investigated under pressure of 6.5-10.5 GPa at a constant temperature of 1850℃.A new carbon-selenium compound with a most plausible chemical formula of SeC and a WC-type hexagonal structure(space group P6m2)has been discovered in the recovered samples sintered at 10.5 GPa and 1850℃.Refined lattice parameters are as follows:a=2.9277(4)A,c=2.8620(4)A,V=21.245(4)A^*** diamond compacts hot-pressed at 10.5 GPa have excellent mechanical properties with a Vickers hardness of about 68 GPa at a loading force of 19.6 *** intergrowths observed in these samples may have benefited from the catalytic effects of Se/SeC on the nucleation and crystal growth of diamond.

关键词： Diamond hexagonal Vickers

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Redispersible and stable amorphous calcium phosphate nanoparticles functionalized by an organic bisphosphate

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Chinese Chemical Letters 2014年第2期25卷 295-298页

作者： Rong-Hui Lai ping-Jiang Dong Yong-Li wang Jian-Bin Luo Department of Chemistry and Environmental Protection Engineering Southwest University for Nationalities

Although much effort has been focused on the preparation of stable amorphous calcium phosphate （ACP） nanoparticles in aqueous solution, the redispersibility and long-term stability of ACP nanoparticles in aqueous solution remains an unresolved problem. In this work, stable colloidal ACPs were prepared by using an organic bisphosphonate （BP） as a sterically hindered agent in aqueous solution. The harvested calcium phosphate nanoparticles were characterized by inductively coupled plasma atomic emission spectrometry （ICP-AES）, Fourier transform infrared （FTIR）, X-ray diffraction （XRD）, dynamic light scattering （DLS） and transmission electron microscopy （TEM）. ICP-AES, FTIR and XRD results suggested the particles were ACP. DLS and TEM results indicated that the size of the ACP nanoparticles were in the range of 60 nm with a spherical morphology. The resulting calcium phosphate nanoparticles retained its amorphous nature in aqueous solution for at least 6 months at room temperature due to the stabilizing effect of the organic bisphosphonate. Moreover, the surface of the ACP nanoparticles adsorbed with the organic bisphosphate used showed good redispersibility and high colloid stability both in organic and aqueous solutions.

关键词： Amorphous calcium phosphate Bisphosphate Nanoparticle Redispersibility Stability

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Wave Attenuation and Turbulence Driven by Submerged Vegetation Under Current-Wave Flow

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China Ocean Engineering 2024年第4期38卷 602-611页

作者： HUANG Yu-ming Ding Lei wang Yi-fei CHEN Ben YANG Xiao-yu DOU Xi-ping School of Water Resources and Hydropower Engineering Wuhan UniversityWuhan430072China Key Laboratory of Port Waterway and Sedimentation Engineering of MOTNanjing Hydraulic Research InstituteNanjing 210029China

A set of laboratory experiments are carried out to investigate the effect of following/opposing currents on wave *** vegetation canopies with aligned and staggered configurations were tested under the condition of various regular wave heights and current velocities,with the constant water depth being 0.60 m to create the desired submerged *** show that the vegetation-induced wave dissipation is enhanced with the increasing incident wave height.A larger velocity magnititude leads to a greater wave height attenuation for both following and opposing current ***,there is a strong positive linear correlation between the damping coefficientβand the relative wave height H_(0)/h,especially for pure wave *** the velocity profile,the distributions of U_(min)and U_(max)show different patterns under combined wave and *** time-averaged turbulent kinetic energy(TKE)vary little under pure wave and U_(c)=±0.05 m/s *** the increase of flow velocity amplitude,the time-averaged TKE shows a particularly pronounced increase trend at the top of the *** vegetation drag coefficients are obtained by a calibration *** empirical relations of drag coefficient with Reynolds and Keulegane-Carpenter numbers are proposed to further understand the wave-current-vegetation interaction mechanism.

关键词： wave attenuation rigid vegetation following and opposing currents turbulent kinetic energy

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Synthesis of macrocyclic lactones with methoxysulfonyl side chain

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Chinese Chemical Letters 2008年第4期19卷 403-405页

作者： Chuan Jin Hou Xiao Mei Liang Jing ping Wu Dao Quan wang Key Lab of Pesticide Chemistry and Application Technology Department of Applied ChemistryChina Agricultural UniversityBeijing 100094China

Two representative macrocyclic lactones with methoxysulfonyl side chain（5a and 5b）were synthesized employing Michael addition with acrolein and ring enlargement as the key steps,starting from potassium,α-oxocycloai... 详细信息

关键词： Macrocyclic lactone Ring enlargement α-Hydroxypropyl-α-methoxysulfonylcycloalkanones Synthesis

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