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Theoretical Prediction of Gibbs Free Energies of Formation for Crystallineα-MOOH andα-M_2O_3 Based on a Linear Free-Energy Relationship

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Acta Geologica Sinica(English Edition) 2011年第3期85卷 656-660页

作者： sun xiaoming School of Marine Sciences Sun Yat-Sen University Guangzhou Guangdong 510275 China Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering Guangzhou 5102 75 China Department of Earth Sciences Sun Yat-Sen University Guangzhou Guangdong 510275 China

In the present study,the modified Sverjensky-Molling equation,derived from a linear-free energy relationship,is used to predict the Gibbs free energies of formation of crystalline phases ofα-MOOH （with a goethite structure）andα-M_2O_3（with a hematite structure）from the known thermodynamic properties of the corresponding aqueous trivalent cations（M^（3＋））.The modified equation is expressed asΔG_（f,M_VX）~0=a_（M_VX）ΔG_（0,M^（3＋））^（0）＋b_（M_VX）＋β_（M_VXγM^（3＋））,where the coefficients a_（M_VX）,b_（M_VX）,andβ_（M_VX） characterize a particular structural family of M_VX（M is a trivalent cation[M^（3＋）]and X represents the remainder of the composition of solid）;γ^（3＋）is the ionic radius of trivalent cations（M^（3＋））;ΔG_（f,M_VX）~0 is the standard Gibbs free energy of formation of M_vX;andΔG_（n,M^（3＋））~0 is the non-solvation energy of trivalent cations（M^（3＋））.By fitting the equation to the known experimental thermodynamic data,the coefficients for the goethite family（α-MOOH）are a_（M_VX）=0.8838,b_（M_VX）=-424.4431（kcal/mol）,andβ_（M_VX）=115（kcal/ mol.（？））,while the coefficients for the hematite family（α-M_2O_3）are a_（M_VX）=1.7468,b_（M_VX）=-814.9573（kcal/ mol）,andβ_（M_VX）=278（kcal/mol.（？））.The constrained relationship can be used to predict the standard Gibbs free energies of formation of crystalline phases and fictive phases（*** that are thermodynamically unstable and do not occur at standard conditions）within the isostructural families of goethite（α-MOOH）and hematite（α-M_2O_3）if the standard Gibbs free energies of formation of the trivalent cations are known.

关键词： α-MOOH α-M_2O_3 Gibbs free energy theoretical prediction

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H_(2)O_(2) treatment boosts activity of NiFe layered double hydroxide for electro-catalytic oxidation of urea

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Journal of Environmental Sciences 2023年第7期129卷 152-160页

作者： Jinshan Wei Jin Wang xiaoming sun College of Materials Science and Engineering Key Laboratory of Optoelectronic Devices and SystemsCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China State Key Laboratory of Chemical Resource Engineering College of ChemistryBeijing University of Chemical TechnologyBeijing 100029China

Urea oxidation reaction(UOR)provides a method for hydrogen production besides wastewater treatment,but the current limited catalytic activity has prevented the ***,we develop a novel H_(2)O_(2) treatment strategy for tailoring the surface oxygen ligand of NiFe-layered double hydroxides(NiFe-LDH).The sample after H_(2)O_(2) treatment(NiFeOLDH)shows significant enhancement on UOR efficiency,with the potential of 1.37 V(RHE)to reach a current density of 10 mA/cm^(2).The boost is attributed to the richness adsorption O ligand on NiFeO-LDH as revealed by XPS and Raman *** calculation indicates formation of two possible types of oxygen ligands:adsorbed oxygen on the surface and exposed from hydroxyl group,lowered the desorption energy of CO_(2) product,which lead to the lowered onset *** strategy is further extended to NiFe-LDH nano sheet on Ni foam to reach a higher current density of 440 mA/cm^(2) of UOR at 1.8 V(RHE).The facile surface O ligand manipulation is also expected to give chance to many other electro-catalytic oxidations.

关键词： NiFe-LDH Urea oxidation reaction H_(2)O_(2)treatment Electro-catalysis Hydrogen production

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Quantum search with prior knowledge

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Science China(Information Sciences) 2024年第9期67卷 321-329页

作者： Xiaoyu HE xiaoming sun Jialing ZHANG State Key Lab of Processors Institute of Computing Technology Chinese Academy of Sciences School of Computer Science and Technology University of Chinese Academy of Sciences

The combination of contextual side information and search is a powerful paradigm in the scope of artificial intelligence. The prior knowledge enables the identification of possible solutions but may be imperfect. Contextual information can arise naturally, for example in game AI where prior knowledge is used to bias move decisions. In this work we investigate the problem of taking quantum advantage of contextual information, especially searching with prior knowledge. We propose a new generalization of Grover's search algorithm that achieves the optimal expected success probability of finding the solution if the number of queries is fixed. Experiments on small-scale quantum circuits verify the advantage of our algorithm. Since contextual information exists widely, our method has wide applications. We take game tree search as an example.

关键词： quantum computing quantum search quantum query algorithm prior knowledge

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Follow the perturbed approximate leader for solving semi-bandit combinatorial optimization

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Frontiers of Computer Science 2021年第5期15卷 161-172页

作者： Feidiao YANG Wei CHEN Jialin ZHANG xiaoming sun Institute of Computing Technology Chinese Academy of SciencesBejing 100190China University of Chinese Academy of Sciences Beijing 100190China Microsoft Research Asia Beijing 100080China

Combinatorial optimization in the face of uncertainty is a challenge in both operational research and machine *** this paper,we consider a special and important class called the adversarial online combinatorial optimization with semi-bandit feedback,in which a player makes combinatorial decisions and gets the corresponding feedback *** existing algorithms focus on the regret guarantee or assume there exists an efficient offline oracle,it is still a challenge to solve this problem efficiently if the offline counterpart is *** this paper,we propose a variant of the Follow-the-Perturbed-Leader(FPL)algorithm to solve this *** the existing FPL approach,our method employs an approximation algorithm as an offline oracle and perturbs the collected data by adding nonnegative random *** ap-proach is simple and computationally ***,it can guarantee a sublinear(1+ε)-scaled regret of order O(T^(2/3))for any smallε>0 for an important class of combinatorial optimization problems that admit an FPTAS(fully polynomial time approximation scheme),in which T is the number of rounds of the learning *** addition to the theoretical analysis,we also conduct a series of experiments to demonstrate the performance of our algorithm.

关键词： online learning online combinatorial optimization semi-bandit follow-the-perturbed-leader

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Adaptive Neural Region Tracking Control of Multi-fully Actuated Ocean Surface Vessels

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IEEE/CAA Journal of Automatica Sinica 2014年第1期1卷 77-83页

作者： xiaoming sun Shuzhi Sam Ge the Department of Automation Science and Electrical Engineering Beihang University (BUAA) the Department of Computer Science and Engineering University of Electronic Science and Technology of China Department of Electrical and Computer Engineering National University of Singapore

In this paper, adaptive neural network region tracking control is designed to force a group of fully actuated ocean vessels with limited sensing range to track a common moving target region, in the presence of uncertainties and unknown disturbances. In this control concept, the desired objective is specified as a moving region instead of a stationary point, region or a path. The controllers guarantee the connectivity preservation of the dynamic interaction network, and no collisions happen between any ocean vessels in the group. The tracking control design is based on the artificial potential functions, approximation-based backstepping design technique, and Lyapunov s method. It is proved that under the adaptive neural network control law, the tracking error of each ocean vessel converges to an adjustable neighborhood of the origin, although some of them do not access the desired target region directly. Simulation results are presented to illustrate the performance of the proposed approach.

关键词： Region tracking neural networks formation control connectivity maintenance collision avoidance

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Failure mechanism of pump chambers and their optimized design in deep mining at Qishan Coal Mine

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Mining Science and Technology 2010年第6期20卷 825-830页

作者： sun xiaoming WU Chuangzhou CAI Feng State Key Laboratory of Deep Rock Mechanics and Engineering Beijing 100083 China School of Mechanics and Civil Engineering China University of Mining & Technology Beijing 100083 China

Pump chambers, normally used as dominant structures in mining engineering to insure the safety and production of un-derground coal mines, become generally deformed under conditions of deep mining. Given the geology and engineering condition of Qishan Coal Mine in Xuzhou, the failure characteristics of pump chambers at the –1000 m level show that the main cause can be attributed to the spatial effect induced by intersectional chambers, where one pump is constructed per well. We developed an opti-mized design of the pump room, in which the pump wells in the traditional design are integrated into one compounding well. We suggest that the new design can limit the spatial effect of intersectional chambers during construction given our relevant numerical simulation. The new design is able to simplify the structure of the pump chamber and reduce the amount of excavation required. Based on a bolt-mesh-anchor with a rigid gap coupling supporting technology, the stability of pump chamber can be improved greatly.

关键词： deep mining pump chambers failure mechanism numerical simulation optimized design

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Paleoporosity and critical porosity in the accumulation period and their impacts on hydrocarbon accumulation—A case study of the middle Es3 member of the Paleogene formation in the Niuzhuang Sag, Dongying Depression, Southeastern Bohai Bay Basin, East Chi

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Petroleum Science 2014年第4期11卷 495-507页

作者： Liu Mingjie Liu Zhen sun xiaoming Wang Biao School of Geoscience and Technology Southwest Petroleum University State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum (Beijing) Research Institute of Geophysical Exploration of Huabei Oilfield CNPC

Similar reservoir sandbodies and fault conduit systems in the sandstone reservoirs in the middle Es3 member of the Niuzhuang Sag have been problematic for a long time. The following problems remain unsolved： 1） The distribution of sandstone porosity is inconsistent with the hydrocarbon accumulation. The oil sandstones have low porosity instead of high porosity. 2） Sandstones, which have the same properties, have different levels of oiliness, and the sandstones with almost the same properties show different degrees of oil-bearing capacity. This study analyzes the condition of reservoirs in the research area during the accumulation period in terms of paleoporosity estimation and discusses the critical porosity of the sandstone reservoirs during the same period. The following conclusions can be drawn from the results. 1） Although reservoir properties are low at present and some reservoirs have become tight, the paleoporosity ranging from 18% to 25% is greater than the critical porosity of 13.9%. As the： loss of porosity is different in terms of burial history, the present porosity cannot reflect porosity during the accumulation period. Similar/y, high porosity during the accumulation period does not indicate that tbe present porosity is high. 2） The present reservoir location is consistent with the distribution of high paleoporosity during the accumulation period. This result indicates that high porosity belts are prone to hydrocarbon accumulation because of the dominant migration pathways generated as a result of property discrepancies under similar fault conduit conditions. Consequently, the hydrocarbon mainly accumulates in high porosity belts. Paleoporosity during the accumulation period is found to be a vital controlling factor. Therefore, high paleoporosity sandstones in the middle Es3 member of the Niuzhuang Sag have great potential for future exploration.

关键词： Paleoporosity critical porosity dominant migration pathways hydrocarbon accumulation,middle Es3 member Niuzhuang Sag Bohai Bay Basin

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Stable Ultrahigh Specific Capacitance of NiO Nanorod Arrays

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Nano Research 2011年第7期4卷 658-665页

作者： Zhiyi Lu Zheng Chang Junfeng Liu xiaoming sun State Key Laboratory of Chemical Resource Engineering P. O. Box 98 Beijing University of Chemical Technology Beijing 100029China

Previously reported examples of electrochemical pseudocapacitors based on cheap metal oxides have suffered from the need to compromise between specific capacitance, rate capacitance, and reversibility. Here we show that NiO nanorod arrays on Ni foam have a combination of ultrahigh specific capacitance （2018 F/g at 2.27 A/g）, high power density （1536 F/g at 22.7 A/g）, and good cycling stability （only 8% of capacitance was lost in the first 100 cycles with no further change in the subsequent 400 cycles）. This resulted in an improvement in the reversible capacitance record for NiO by 50% or more, reaching 80% of the theoretical value, and demonstrated that a three-dimensional regular porous array structure can afford all of these virtues in a supercapacitor. The excellent performance can be attributed to the slim （〈 20 nm） rod morphology, high crystallinity, regularly aligned array structure and strong bonding of the nanorods to the metallic Ni substrate, as revealed by scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and X-ray diffraction （XRD）.

关键词： Pseudocapacitance cycling stability NiO array nanorod

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Heterovalent ion exclusion principle in atomically single site metal(hydr)oxide catalysts design

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Science Bulletin 2024年第13期69卷 2009-2012页

作者： Daojin Zhou Fengmei Wang Yun Kuang xiaoming sun State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China Ocean Hydrogen Energy R&D Center Research Institute of Tsinghua University in ShenzhenShenzhen 518057China

Single-atom catalysts(SACs)are a series of catalysts in which all metal species are atomically dispersed on oxides,zeolites,sulfides,carbons,and so *** concept describing how atoms arrange with their nearest neighbors was proposed in 1969 by Van Hardeveld and co-workers[1],and researchers witness the growing popularity of SACs[2].However,the first long-standing issue in SACs is that the low concentration of active sites on the ***,weak chemical bonds between active sites with supports cannot sustain the functionalities of the SACs during long-term reactions,especially ones run at harsh conditions(high temperature or humidity,strong oxidative conditions).The loss or aggregation of active sites in SACs require substantial efforts to address the existing drawbacks in traditional SACs.

关键词： atomic bonds valent

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Thermography analyses of rock fracture due to excavation and overloading for tunnel in 30° inclined strata

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Science China(Technological Sciences) 2017年第6期60卷 911-923页

作者： sun xiaoming XU HuiChen HE ManChao GONG WeiLi CHEN Feng State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology Beijing 10083 China School of Mechanics and Civil Engineering China University of Mining & Technology Beijing 10083 China

Large-scale physical model test of 30°inclined strata was conducted to investigate the damage mechanisms during the excavation and overloading using infrared *** experiment results were presented with thermal images which were divided into three stages including a full face excavation stage,a staged excavation stage,and an overloading *** obtained results were compared with the previously reported results from horizontal,45?,60?,and vertical strata *** temperature(IRT)for 30°inclined strata model descended with multiple fluctuations during the full-face *** the staged excavation,the excavation damage zone(EDZ)showed enhanced faulting-like strips as compared in the 45?,60?,and vertical models,indicating the intensified stress redistribution occurred in the adjacent rock *** contrast,EDZ for the horizontal strata existed in a plastic-formed *** the overloading,abnormal features in the thermal images were observed preceding the coalescence of the propagating *** ultimate failure of the model was due primarily to the floor heave and the roof fall.

关键词： deep tunnel inclined strata failure process large-scale physical model infrared thermal imaging technology

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