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Dithizone-functionalized C18 online solid-phase extraction-HPLC-ICP-MS for speciation of ultra-trace organic and inorganic mercury in cereals and environmental samples

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Journal of Environmental Sciences 2022年第5期34卷 403-410页

作者： Ying Wang Ailing Zhu Yingying fang Changjun Fan Yanli guo Zhiqiang Tan Yongguang Yin Yong Cai Guibin jiang Laboratory of Environmental Nanotechnology and Health Effect Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China School of Environment Hangzhou Institute for Advanced StudyUCASHangzhou 310024China Shimadzu China Innovation Center Shimadzu(China)Co.LTDBeijing 100020China Department of Chemistry and Biochemistry Florida International UniversityMiamiFL 33199United States

A simple and efficient dithizone-functionalized solid-phase extraction(SPE)procedure,online coupled with high-performance liquid chromatography(HPLC)-inductively coupled plasma mass spectrometry,was developed for the first time for enrichment and determination of ultra-trace mercury(Hg)species(inorganic divalent Hg(Hg(Ⅱ)),methylmercury(CH_(3)Hg(Ⅱ))and ethylmercury(C_(2)H_(5)Hg(Ⅱ))in cereals and environmental *** the proposed method,functionalization of the commercial C_(18) column with dithizone,enrichment,and elution of the above Hg species can be completed online with the developed SPE device.A simple solution of 2-mercaptoethanol(1%(V/V))could be used as an eluent for both the SPE and HPLC separation of Hg species,significantly simplifying the method and *** online SPE method was optimized by varying dithizone dose,2-mercaptoethanol concentration,and sample *** addition,the effect of pH,coexisting interfering ions,and salt effect on the enrichment was also *** the optimized conditions,the detection limits of Hg species for 5 mL water sample were 0.15 ng/L for Hg(Ⅱ),0.07 ng/L for CH_(3)Hg(Ⅱ),and 0.04 ng/L for C_(2)H_(5)Hg(Ⅱ)with recoveries in the range of 85%-100%.The developed dithizone-functionalized C_(18) SPE column can be reused after a single function-alization,which significantly simplifies the enrichment ***,the stability of Hg species enriched on the SPE column demonstrated its suitability for field sampling of Hg species for later laboratory *** environment-friendly method offers a robust tool to detect ultra-trace Hg species in cereals and environmental samples.

关键词： Mercury speciation Online solid-phase extraction HPLC-ICP-MS Dithizone Cereals Natural water

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Theoretical Study on the Catalytic Activity and Sulfur Resistibility of Amorphous Alloy Ni-B-P

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Chinese Journal of Structural Chemistry 2007年第3期26卷 273-280页

作者： fang Zhi-Gang guo Jing-Xue School of Chemical Engineering University of Science and Technology Liaoning Anshan 114051 China

In the present paper, one hundred cluster models NinBP （n = 1-6） have been designed and studied by density functional theory （DFT） to get an insight into the local structure, catalytic properties and sulfur resistibility of amorphous alloy Ni-B-P. The configurations in triplet state are found more stable than those in the singlet state. It is found： that as the content of Ni in the clusters increases, the value of Fermi level in clusters fluctuated, which shows that the content of Ni can influence the Fermi level to a certain extent. Based on the Fermi level and DOS, we consider the activity of catalyst in hydrogenation reaction is the best in cluster Ni3BP. On the basis of the charge of clusters NinBP （n = 1 -6）, we conclude the amorphous alloy Ni-B-P with high Ni content has better sulfur resistibility and the best hydrogenation activity, strong sulfur resistibility appears in clusters Ni3BP, and the amorphous alloy Ni60B20P20 with similar proportion is expected to prepare in the future.

关键词： amorphous alloy Ni-B-P DFT catalytic activity sulfur resistibility

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Unprotected quadratic band crossing points and quantum anomalous Hall effect in FeB_(2) monolayer

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Science China(Physics,Mechanics & Astronomy) 2022年第5期65卷 75-80页

作者： DongYu Wu YunPeng Huang Song Sun JiaCheng Gao ZhaoPeng guo HongMing Weng Zhong fang Kun jiang ZhiJun Wang Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Quadratic band crossing points(QBCPs)and quantum anomalous Hall effect(QAHE)have attracted the attention of both theoretical and experimental researchers in recent *** on first-principle calculations,we find that the FeB_(2) monolayer is a nonmagnetic semimetal with QBCPs at *** symmetry analysis and k·p invariant theory,we find that the QBCP is not protected by rotation symmetry and consists of two Dirac points with the same chirality(Berry phase of 2π).Once introducing Coulomb interactions,we find that there is a spontaneous-time-reversal-breaking instability of the spinful QBCPs,which gives rise to a C=2 QAH insulator with orbital moment ordering.

关键词： two dimension topological phase quantum anomalous Hall effect

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Structural Synthesis of a Class of 2R2T Hybrid Mechanisms

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Chinese Journal of Mechanical Engineering 2016年第4期29卷 703-709页

作者： TIAN Chunxu fang Yuefa guo Sheng School of Mechanical Electronic and Control EngineeringBeijing Jiaotong University

Conventional overconstrained parallel manipulators have been widely studied both in industry and academia,however the structural synthesis of hybrid mechanisms with additional constraints is seldom studied,especially for the four degrees of freedom（DOF） hybrid *** order to develop a manipulator with additional constraints,a class of important spatial mechanisms with coupling chains（CCs） whose motion type is two rotations and two translations（2R2T） is *** on screw theory,the combination of different types of limbs which are used to construct parallel mechanisms and coupling chains is *** basic types of the general parallel mechanisms and geometric conditions of the kinematic chains are given using constraint synthesis ***,the 2R2T motion pattern hybrid mechanisms which are derived by adding coupling chains between different serial kinematic chains（SKCs） of the corresponding parallel mechanisms are *** to the constraint analysis of the mechanisms,the movement relationship of the moving platform and the kinematic chains is derived by disassembling the coupling *** last,fourteen novel hybrid mechanisms with two or three serial kinematic chains are *** proposed novel hybrid mechanisms and construction method enrich the family of the spatial mechanisms and provide an instruction to design more complex hybrid mechanisms.

关键词： parallel mechanisms structural synthesis hybrid mechanisms screw theory

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Response of Nitrogen Leaching to Nitrogen Deposition in Disturbed and Mature Forests of Southern China

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Pedosphere 2009年第1期19卷 111-120页

作者： fang Yun-Ting M. YOH MO jiang-Ming P. GUNDERSEN ZHOU guo-Yi Dinghushan Forest Ecosystem Research Station South China Botanical Garden the Chinese Academy of Sciences Zhaoqing Guangdong 520670 （China） Tokyo University of Agriculture and Technology Tokyo 183-8509 （Japan） Forest ＆ Landscape Denmark Faculty of Life Sciences University of Copenhagen Hoersholm Kongevej 112970 （Denmark）

Current nitrogen (N) leaching losses and their responses to monthly N additions were investigated under a disturbed pine (Pinus massoniana) forest and a mature monsoon broadleaf forest in southern China. N leaching losses from both disturbed and mature forests were quite high (14.6 and 29.2 kg N ha-1 year-1, respectively), accounting for 57% and 80% of their corresponding atmospheric N inputs. N leaching losses were substantially increased following the first 1.5 years of N applications in both forests. The average increases induced by the addition of 50 and 100 kg N ha-1 year-1 were 36.5 and 24.9 kg N ha-1 year-1, respectively, in the mature forest, accounting for 73.0% and 24.9% of the annual amount of N added, and 14.2 and 16.8 kg N ha-1 year-1 in the disturbed forest, accounting for 28.4% and 16.8% of the added N. Great N leaching and a fast N leaching response to N additions in the mature forest might result from long-term N accumulation and high ambient N deposition load (greater than 30 kg N ha-1 year-1 over the past 15 years), whereas in the disturbed forest, it might result from the human disturbance and high ambient N deposition load. These results suggest that both disturbed and mature forests in the study region may be sensitive to increasing N deposition.

关键词： atmospheric N deposition N addition N leaching loss N saturation subtropical forests

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Recent progress in single-atom nanozymes research

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Nano Research 2023年第2期16卷 1878-1889页

作者： Bing jiang Zhanjun guo Minmin Liang Experimental Center of Advanced Materials School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081China

Single-atom nanozyme(SAzyme)is the hot topic of the current nanozyme *** intrinsic properties,such as high activity,stability,and low cost,present great substitutes to natural ***,its fundamental characteristics,i.e.,maximized atom utilizations and well-defined geometric and electronic structures,lead to higher catalytic activities and specificity than traditional *** have been applied in many biomedical areas,such as anti-tumor therapy,biosensing,antibiosis,and anti-oxidation ***,we will discuss a series of representative examples of SAzymes categorized by their biomedical applications in this *** the end,we will address the future opportunities and challenges SAzymes facing in their designs and applications.

关键词： single-atom nanozymes natural enzymes enzyme-like activity biomedical applications

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Multi-objective Optimization of a Parallel Ankle Rehabilitation Robot Using Modified Differential Evolution Algorithm

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Chinese Journal of Mechanical Engineering 2015年第4期28卷 702-715页

作者： WANG Congzhe fang Yuefa guo Sheng School of Mechanical Electronic and Control Engineering Beijing Jiaotong University

Dimensional synthesis is one of the most difficult issues in the field of parallel robots with actuation redundancy. To deal with the optimal design of a redundantly actuated parallel robot used for ankle rehabilitation, a methodology of dimensional synthesis based on multi-objective optimization is presented. First, the dimensional synthesis of the redundant parallel robot is formulated as a nonlinear constrained multi-objective optimization problem. Then four objective functions, separately reflecting occupied space, input/output transmission and torque performances, and multi-criteria constraints, such as dimension, interference and kinematics, are defined. In consideration of the passive exercise of plantar/dorsiflexion requiring large output moment, a torque index is proposed. To cope with the actuation redundancy of the parallel robot, a new output transmission index is defined as well. The multi-objective optimization problem is solved by using a modified Differential Evolution（DE） algorithm, which is characterized by new selection and mutation strategies. Meanwhile, a special penalty method is presented to tackle the multi-criteria constraints. Finally, numerical experiments for different optimization algorithms are implemented. The computation results show that the proposed indices of output transmission and torque, and constraint handling are effective for the redundant parallel robot; the modified DE algorithm is superior to the other tested algorithms, in terms of the ability of global search and the number of non-dominated solutions. The proposed methodology of multi-objective optimization can be also applied to the dimensional synthesis of other redundantly actuated parallel robots only with rotational movements.

关键词： ankle rehabilitation parallel robot multi-objective optimization differential evolution algorithm

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Bionic functional membranes for separation of oil-in-water emulsions

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Friction 2024年第9期12卷 1909-1928页

作者： Chaolang CHEN Ruisong jiang Zhiguang guo School of Mechanical Engineering Sichuan UniversityChengdu 610065China School of Materials Science and Engineering Hubei UniversityWuhan 430062China

The separation of oil-in-water emulsion is an urgent challenge because its massive production and discharge from daily and industrial activities have caused severe hazards to the ecosystem and serious threats to human *** technology is considered an outstanding solution strategy for the separation of oil-in-water emulsions due to its unique advantages of low cost,high efficiency,easy operation,and environmental ***,the membrane is easily fouled by the emulsion oil droplets during the separation process,causing a sharp decline in permeation flux,which greatly inhibits the long-term use of the membrane and largely shortens the membrane’s ***,it was found that endowing the membranes with special wettability e.g.,superhydrophilic and superoleophobic can greatly enhance the permeability of the continuous water phase and inhibit the adhesion of oil droplets,thus promoting the separation performance and anti-oil-fouling property of membrane for oily *** this paper,we review and discuss the recent developments in membranes with special wettability for separating oil-in-water emulsions,including the mechanism analysis of emulsion separation membrane,membrane fouling issues,design strategies,and representative studies for enhancing the membrane’s anti-oil-fouling ability and emulsion separation performance.

关键词： bionic surface membranes wettability oil-in-water emulsions oil-water separation

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On game-based control systems and beyond

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National Science Review 2020年第7期7卷 1116-1117页

作者： Renren Zhang fang Wang Lei guo Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of Sciences Data Science Institute Shandong University

This perspective first expounds on the reasons behind the introduction of the game-based control systems(GBCS), delineates their features,provides some examples, and put forward some research problems. The paper then points out that more complex regulation problems on the now rapidly developing man-machine integration systems may also be investigated by expanding the scope of the GBCS.

关键词： Control systems

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Theory of Degrees of Freedom for Parallel Mechanisms with Three Spherical Joints and Its Applications

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Chinese Journal of Mechanical Engineering 2015年第4期28卷 737-746页

作者： QU Haibo fang Yuefa guo Sheng School of Mechanical Electronic and Control Engineering Beijing Jiaotong University

The analysis of degrees of freedom（DOF） of a moving platform is the fundamental problem in kinematics of parallel mechanism. However, many problems should be considered to correctly perform the DOF calculation by using the traditional DOF criterion, and it is difficult to find a DOF criterion suitable for all kinds of mechanisms. A rule that can be used to determine the position and orientation of the moving platform is presented. Based on the proposed rule, a new form of DOF criterion is proposed, which is suitable for a class of parallel mechanisms with three spherical joints attached to the moving platform. The basic types of generalized limb structures are given based on the possible dimension of achieving the center of spherical joint attached to the moving platform, and the general steps of analyzing the DOF are presented. This proposed formula simplifies the DOF analysis of parallel mechanisms with spherical joints attached to the moving platform, and plays an important role in structural synthesis of such parallel mechanisms.

关键词： parallel mechanism DOF criterion spherical joint structural synthesis

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