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Heterocatalytic ethylene methoxycarbonylation via a pseudo-hydride pathway over Pt_(1)/MoS_(2)

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Science China Chemistry 2024年第8期67卷 2427-2428页

作者： Bo-hang zhao Bin Zhang Institute of Molecular Plus Department of ChemistrySchool of ScienceTianjin UniversityTianjin 300072China

Ethylene (C2H4) methoxycarbonylation (EMC) with CO and methanol (CH3OH) to methyl propanoate (MP) is industrially important due to its 100% atom efficiency [1].However, the heavy reliance on homogeneous Pd-based catalysts and strong acid media over commercial EMC processes still causes economic and environmental concerns [2]. At present, supported single-atom catalysts (SACs) can serve as bridges for accessing homogeneous catalysts in traditional heterogeneous catalytic processes.

关键词： processes. catalytic hydride

Synthesis and Crystal Structure of a New Complex [CuL(Phen)]·NO_3

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Chinese Journal of Structural Chemistry 2006年第11期25卷 1343-1346页

作者： QIU Xiao-hang zhao Jun TONG Xiao-Lan Department of Chemistry Nankai University Tianjin 300071 China

A new mononuclear copper（Ⅱ） complex [CuL（Phen）]-NO3 （L - 2-{2-[（3,5-dibro- mosalicylidene）amino]ethyl }- 1 H- 1,3-benzimidazole, Phen = 1,10-phenanthroline） has been synthesized and its crystal structure was determined by X-ray diffraction method. It crystallizes in monoclinic, space group C2/c with a = 24.966（7）, b = 15.673（4）, c = 16.600（5） A,β = 123.981（4）°, C28H20Br2CuN604, Mr = 727.86, V = 5386（2） A^3, Z = 8, Dc = 1.795 g/cm^3,μ（MoKα = 3.826 mm^-1, F（000） = 2888, the final R = 0.0508 and wR = 0.1024 for 5440 independent reflections with Rint = 0.1134. The title compound is composed of [CuL（Phen）]＋ cation and NO3^- anion. The coordination geometry around copper atom is a highly distorted trigonal bipyramid consisting of one benzimidazole nitrogen atom, one phenolato oxygen atom and one phenanthroline nitrogen atom on the equatorial plane together with one imine nitrogen atom and one phenanthroline nitrogen atom occupying the axial positions. The hydrogen bonding and π-π stacking interactions link the copper complex molecules into a 3-D supramolecular structure.

关键词： crystal structure copper complex 1,10-phenanthroline hydrogen bonds

High pyrolysis temperature biochar reduced the transport of petroleum degradation bacteria Corynebacterium variabile HRJ4 in porous media

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Journal of Environmental Sciences 2021年第2期33卷 228-239页

作者： Saisai Guo Xiaomei Liu hang zhao Lan Wang Jingchun Tang College of Environmental Science and Engineering Nankai UniversityTianjin 300350China Key Laboratory of Pollution Processes and Environmental Criteria(Ministry of Education) Tianijin 300350China Tianjin Engineering Research Center of Enuironmental Diagnosis and Contamination Remediation Tianjin 300350China

Biochar has been widely applied for the remediation of petroleum-contaminated ***,the effect of biochar on the transport of petroleum degradation bacteria has not been studied.A typical Gram-positive petroleum degradation bacteria-Corynebacterium variabile HRJ4 was used to study the effect of different biochars on bacterial transport and *** indicated that the addition of biochar in sand was effective for reducing the transport of bacteria and poplar sawdust biochar(PSBC)had a stronger hinder effect than corn straw biochar(CSBC).The hindrance was more evident with pyrolysis temperature of biochar raised from 300℃ to 600℃,which was attributed to the increase of specific surface area(309 times).The hindrance effect also enhanced with higher application rate of ***,the reduction of HRJ4 transport was more obvious in higher(25 mmol/L)concentration of Na Cl solution owing to electrostatic attraction *** adsorption of biochar to HRJ4 was defined to contribute to the hindrance of HRJ4 transport *** the influence of feedstocks and pyrolysis temperature on HRJ4 transport,it suggested that specific surface area had the greatest effect on HRJ4 transport,and pore-filling,electrostatic force also contributed to HRJ4 retained in quartz sand *** last,phenol transportation experiment indicated that the restriction of biochar on HRJ4 enhanced the phenol removal rate in the *** study provides a theoretical basis for the interaction of biochar and bacteria,which is vital for the remediation of oil-contaminated soil and groundwater in the field.

关键词： Gram-positive bacteria Feedstocks HRJ4 Transport Retention

Learning practically feasible policies for online 3D bin packing

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Science China(Information Sciences) 2022年第1期65卷 175-191页

作者： hang zhao Chenyang ZHU Xin XU Hui HUANG Kai XU School of Computer Science National University of Defense Technology College of Intelligence Science and Technology National University of Defense Technology College of Computer Science and Software Engineering Shenzhen University

We tackle the online 3 D bin packing problem(3 D-BPP), a challenging yet practically useful variant of the classical bin packing problem. In this problem, the items are delivered to the agent without informing the full sequence information. The agent must directly pack these items into the target bin stably without changing their arrival order, and no further adjustment is permitted. Online 3 D-BPP can be naturally formulated as a Markov decision process(MDP). We adopt deep reinforcement learning, in particular, the on-policy actor-critic framework, to solve this MDP with constrained action space. To learn a practically feasible packing policy, we propose three critical designs. First, we propose an online analysis of packing stability based on a novel stacking tree. It attains a high analysis accuracy while reducing the computational complexity from O(N2) to O(N log N), making it especially suited for reinforcement learning training. Second, we propose a decoupled packing policy learning for different dimensions of placement which enables high-resolution spatial discretization and hence high packing precision. Third, we introduce a reward function that dictates the robot to place items in a far-to-near order and therefore simplifies the collision avoidance in movement planning of the robotic arm. Furthermore, we provide a comprehensive discussion on several key implemental issues. The extensive evaluation demonstrates that our learned policy outperforms the state-of-the-art methods significantly and is practically usable for real-world applications.

关键词： bin packing problem online 3D-BPP reinforcement learning

Fog-computing based mobility and resource management for resilient mobile networks

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High-Confidence Computing

High-Confidence Computing 2024年第2期4卷 145-151页

作者： hang zhao Shengling Wang Hongwei Shi School of Artificial Intelligence Beijing Normal UniversityBeijing 100875China

Mobile networks are facing unprecedented challenges due to the traits of large scale,heterogeneity,and high ***,the emergence of fog computing offers surprisingly perfect solutions considering the features of consumer proximity,wide-spread geographical distribution,and elastic resource *** this paper,we propose a novel mobile networking framework based on fog computing which outperforms others in *** scheme is constituted of two parts:the personalized customization mobility management(MM)and the market-driven resource management(RM).The former provides a dynamically customized MM framework for any specific mobile node to optimize the handoff performance according to its traffic and mobility traits;the latter makes room for economic tussles to find out the competitive service providers offering a high level of service quality at sound ***,our proposed MM and RM schemes can holistically support a full-fledged resilient mobile network,which has been practically corroborated by numerical experiments。

关键词： Resilient mobile networking Fog computing Mobility management Resource management

Evaluation of effective spectral features for glacial lake mapping by using Landsat-8 OLI imagery

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Journal of Mountain Science 2020年第11期17卷 2707-2723页

作者： Zhang Mei-mei zhao hang CHEN Fang ZENG Jiang-yuan Key Laboratory of Digital Earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China State Key Laboratory of Remote Sensing Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China Hainan Key Laboratory of Earth Observation Aerospace Information Research InstituteChinese Academy of SciencesSanya 572029China

Glacial lake mapping provides the most feasible way for investigating the water resources and monitoring the flood outburst hazards in High Mountain ***,various types of glacial lakes with different properties bring a constraint to the rapid and accurate glacial lake mapping over a large *** spectral features to map glacial lakes are diverse but some are generally limited to the specific glaciated regions or lake types,some have unclear applicability,which hamper their application for the large *** this end,this study provides a solution for evaluating the most effective spectral features in glacial lake mapping using Landsat-8 *** 23 frequently-used lake mapping spectral features,including single band reflectance features,Water Index features and image transformation features were selected,then the insignificant features were filtered out based on scoring calculated from two classical feature selection methods-random forest and decision tree *** result shows that the three most prominent spectral features(SF)with high scores are NDWI1,EWI,and NDWI3(renamed as SF8,SF19 and SF12 respectively).Accuracy assessment of glacial lake mapping results in five different test sites demonstrate that the selected features performed well and robustly in classifying different types of glacial lakes without any influence from the mountain ***8 and SF19 are superior for the detection of large amount of small glacial lakes,while some lake areas extracted by SF12 are ***,SF8 achieved better accuracy than the other two features in terms of both Kappa Coefficient(0.8812)and Prediction(0.9025),which further indicates that SF8 has great potential for large scale glacial lake mapping in high mountainous area.

关键词： Glacial lake mapping Landsat-8 OLI Water Index Spectral features

Mechanical Properties of Deep-buried Marble Material Under Loading and Unloading Tests

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Journal of Wuhan University of Technology(Materials Science) 2013年第3期28卷 514-520页

作者：李新平 zhao hang WANG Bin XIAO Taoli Hubei Key Laboratory of Roadway Bridge and Structure Engineering Wuhan University of Technology School of Civil Engineering and Architecture Wuhan University of Technology Changjiang Institute of Survey Planning Design and Research School of Urban Construction Yangtze University

The mechanical properties are essentially different when rock material is subjected to loading or unloading conditions. In this study, loading and unloading tests with various confining pressures are conducted to investigate the mechanical properties of marble material samples taken from the deep diversion tunnels of Jinping II Hydropower Station. The stress-strain relationship, failure characteristics and strength criterion are compared and analyzed based on the experiment results. The results show： in the loading and unloading test, peak strength, lateral strain, axial strain and plastic deformation increase significantly as the confining pressure increases. Lateral strain increased significantly and obvious lateral dilatancy can be observed to the change of confining pressure; The fracture mode is mainly the single shear fracture for the triaxial compression test and post-peak test, angle between the failure surface and the ends of the rock material becomes smaller as the confining pressure increases. Hock-Brown strength criterion reflects the strength characteristics of marble material under two different unloading conditions, and has some supplementary effects to the rock material of mechanical field.

关键词： deep-buried material loading and unloading tests mechanical properties strength criterion shear fracture

Understanding Social Relationships with Person-Pair Relations

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Big Data Mining and Analytics 2022年第2期5卷 120-129页

作者： hang zhao Haicheng Chen Leilai Li Hai Wan the Guizhou Post and Telecommunications Planning and Design Institute Co. Ltd.Guiyang 550003China School of Computer Science and Engineering Sun Yat-sen UniversityGuangzhou 510006China Ping An Technology(Shenzhen)Co. Ltd.Shenzhen 518049China

Social relationship understanding infers existing social relationships among individuals in a given scenario,which has been demonstrated to have a wide range of practical value in ***,existing methods infer the social relationship of each person pair in isolation,without considering the context-aware information for person pairs in the same *** context-aware information for person pairs exists extensively in reality,that is,the social relationships of different person pairs in a simple scenario are always related to each *** instance,if most of the person pairs in a simple scenario have the same social relationship,“friends”,then the other pairs have a high probability of being“friends”or other similar coarse-level relationships,such as“intimate”.This context-aware information should thus be considered in social relationship ***,this paper proposes a novel end-to-end trainable Person-Pair Relation Network(PPRN),which is a GRU-based graph inference network,to first extract the visual and position information as the person-pair feature information,then enable it to transfer on a fully-connected social graph,and finally utilizes different aggregators to collect different kinds of person-pair *** existing methods,the method—with its message passing mechanism in the graph model—can infer the social relationship of each person-pair in a joint way(i.e.,not in isolation).Extensive experiments on People In Social Context(PISC)-and People In Photo Album(PIPA)-relation datasets show the superiority of our method compared to other methods.

关键词： social relationship understanding person-pair relations Person-Pair Relation Network(PPRN)

Ultrafast hydrogen bond dynamics of liquid water revealed by terahertz-induced transient birefringence

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Light(Science & Applications) 2020年第1期9卷 707-716页

作者： hang zhao Yong Tan Liangliang Zhang Rui Zhang Mostafa Shalaby Cunlin Zhang Yuejin zhao Xi-Cheng Zhang Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology School of Optics and PhotonicsBeijing Institute of TechnologyBeijing 100081China Beijing Advanced Innovation Center for Imaging Technology and Key Laboratory of Terahertz Optoelectronics(MoE) Department of PhysicsCapital Normal UniversityBeijing 100048China Shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhen 518055China The Institute of Optics University of RochesterRochesterNY 14627USA

The fundamental properties of water molecules,such as their molecular polarizability,have not yet been *** hydrogen bond network is generally considered to play an important role in the thermodynamic properties of *** terahertz(THz)Kerr effect technique,as a novel tool,is expected to be useful in exploring the low-frequency molecular dynamics of liquid ***,we use an intense and ultrabroadband THz pulse(peak electric field strength of 14.9 MV/cm,centre frequency of 3.9 THz,and bandwidth of 1–10 THz)to resonantly excite intermolecular modes of liquid *** THz field-induced transient birefringence signals are observed in a free-flowing water *** propose a hydrogen bond harmonic oscillator model associated with the dielectric susceptibility and combine it with the Lorentz dynamic equation to investigate the intermolecular structure and dynamics of liquid *** mainly decompose the bipolar signals into a positive signal caused by hydrogen bond stretching vibration and a negative signal caused by hydrogen bond bending vibration,indicating that the polarizability perturbation of water presents competing contributions under bending and stretching conditions.A Kerr coefficient equation related to the intermolecular modes of water is *** ultrafast intermolecular hydrogen bond dynamics of water revealed by an ultrabroadband THz pump pulse can provide further insights into the transient structure of liquid water corresponding to the pertinent modes.

关键词： transient dynamics liquid