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Effect of Wave Nonlinearity on the instantaneous Seabed Liquefaction

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china Ocean Engineering 2024年第1期38卷 93-103页

作者： WANG Zhao-jun SUi Ti-ti ZHANG chi PAN Jun-ning Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of TransportNanjing Hydraulic Research InstituteNanjing 210024China Key Laboratory of Coastal Disaster and Protection(Hohai University) Ministry of EducationNanjing 210098China The National Key Laboratory of Water Disaster Prevention Nanjing 210098China

The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal *** this study,an analytical formula considering the nonlinear wave skewness and asymmetry is adopted to provide wave pressure on the seabed *** liquefaction depth attenuation coefficient and width growth coefficient are defined to quantitatively characterize the nonlinear effect of wave on seabed *** on the 2D full dynamic model of wave-induced seabed response,a detailed parametric study is carried out in order to evaluate the influence of the nonlinear variation of wave loadings on seabed ***,new empirical prediction formulas are proposed to fast predict the maximum liquefaction under nonlinear *** indicate that(1)Due to the influence of wave nonlinearity,the vertical transmission of negative pore water pressure in the seabed is hindered,and therefore,the amplitude decreases significantly.(2)in general,with the increase of wave nonlinearity,the liquefaction depth of seabed decreases *** under asymmetric and skewed wave loading,the attenuation of maximum seabed liquefaction depth is the most significant among all the nonlinear wave ***,highly skewed wave can cause the liquefaction depth of seabed greater than that under linear wave.(3)The asymmetry of wave pressure leads to the increase of liquefaction width,whereas the influence of skewedness is not significant.(4)Compared with the nonlinear waveform,seabed liquefaction is more sensitive to the variation of nonlinear degree of wave loading.

关键词： nonlinear wave seabed response seabed liquefaction numerical simulation liquefaction prediction

Anthracene-bridged“Texas-sized”box for the simultaneous detection and uptake of tryptophan

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chinese Chemical Letters 2024年第9期35卷 175-178页

作者： Dan Luo Jinya Tian Jianqiao Zhou Xiaodong chi State Key Laboratory of Materials Processing and Die&Mold Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Shenzhen Huazhong University of Science and Technology Research institute Shenzhen 518057China

Tryptophan(Trp)is an essential amino acid that plays a critical role in human *** increasing demand for Trp has created a highly promising market,underscoring the urgent necessity for the development of efficient strategies for the simultaneous detection and uptake of ***,we report an expanded“Texas-sized”molecular box(An-TxSB),which incorporates luminescent anthracene bridging subunits and molecular recognition *** luminescent molecular box demonstrates exceptional sensitivity to Trp in water,permitting its precise quantification with a notably low limit of detection(LOD)of 0.42μmol/***,An-TxSB facilitates the proficient uptake of Trp from simulated water samples,thereby revealing an impressive Trp adsorption capacity of up to 226.0μmol/g.

关键词： Macrocycles Host-guest chemistry Biomolecular sensors Molecular recognition Adsorption

chiral boryl radical catalyzed asymmetric radical cycloisomerization

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Science china Chemistry 2024年第7期67卷 2121-2123页

作者： Jiamiao Jin Shi-Chao Ren Yonggui Robin chi National Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide and Agricultural BioengineeringMinistry of EducationGuizhou UniversityGuiyang 550025China School of Chemistry Chemical Engineeringand BiotechnologyNanyang Technological UniversitySingapore 637371Singapore

Asymmetric catalytic organic synthesis is of profound importance in modern research and industries,providing optically enriched molecules with diverse structures and functions[1].Enzymes,transition metal complexes,and simple organic molecules have all been found as powerful catalysts that enable the bond breaking and forming events with excellent control over stereo-selectivity *** the realm of designed small molecule organic catalysts.

关键词： radical catalyzed asymmetric

Efficient Preparation and Electrochemical Properties of BiOCl/Graphite by One-step Solvothermal Method

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 651-657页

作者：门丽娟 FEi chi LiU An 陈春钰 ZHOU Jiankang JU Dianchun School of Metallurgy Engineering Jiangsu University of Science and TechnologyZhangjiagang 215600China

We used the surface-pretreated graphite paper(Gp)as a carrier and loaded BiOCl with high selectivity to Cl^(-)on its surface by solvothermal method to form BiOCl@Gp *** morphology,structure,and composition of the materials were characterized by scanning electron microscopy and nitrogen adsorption/desorption,and the results showed that the spherical BiOCl particles were uniformly dispersed on the surface of the Gp,forming a mesoporous BiOCl@Gp composite with a specific surface area of 22.82 m^(2)/g and a pore volume of 0.043 cm3/***,cyclic voltammetry and electrochemical impedance spectroscopy were used to test the electrochemical properties of the composites,and the stability of BiOCl and the high conductivity of Gp were synergistic,the BiOCl@Gp exhibited a specific capacitance of 30.2 F·g^(-1) at a current density of 0.5 A·g^(-1),and the selectivity of the BiOCl@Gp materials for Cl^(-)was significantly higher than that of SO_(4)^(2-),NO_(2)^(-),and HCO_(3)^(-).Therefore,BiOCl@Gp composite electrode materials can be used for the selective adsorption of Cl^(-)in wastewater,in order to achieve efficient wastewater recycling.

关键词： solvothermal method bismuth oxychloride electrochemistry electrode materials

Regulating the crystal phase of bismuth-based semiconductors for promoted photocatalytic performance

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Science china Chemistry 2024年第6期67卷 1839-1864页

作者： Zhaohui Wu Mei-chi Chong Shiying Zhang Junshan Li Yongfa Zhu Hunan Key Laboratory of Applied Environmental Photocatalysis Changsha UniversityChangsha410022China Department of Chemistry Tsinghua UniversityBeijing100084China institute for Advanced Study Chengdu UniversityChengdu610106China

Numerous bismuth-based semiconductors(BBSs)with sophisticated and desirable structures used as photocatalysts for efficient photocatalytic degradation of water organic contaminants have attracted considerable ***,regulating the crystal phases and phase transition of BBSs for promoted photocatalytic performance is ***,the unique crystal structure and band structure features of each typical BBSs,and the vital roles on phase controlling of each phase were systematically presented based on the classification of ***,the critical factors for the phase transition of BBSs and intrinsic driving forces endowed by phases of BBSs for enhanced photocatalytic performance of organic contaminants removal were also *** review will provide systematical guidelines and horizons for regulating the crystal phase and phase transition of BBSs,promoting photocatalytic degradation and mineralization of organic contaminants.

关键词： bismuth-based semiconductors phase regulation photocatalytic performances organic contaminants

Review of the Configuration and Transient Stability of Large-scale Renewable Energy Generation through Hybrid DC Transmission

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CES Transactions on Electrical Machines and Systems 2024年第2期8卷 115-126页

作者： Xinshou Tian Yongning chi Longxue Li Hongzhi Liu institute of Energy Power innovation North China Electric Power UniversityBeijing 102206China china Electric Power Research institute No.15Xiaoying East RoadQingheHaidian DistrictBeijing 100192China.

Based on the complementary advantages of Line Commutated Converter(LCC)and Modular Multilevel Converter(MMC)in power grid applications,there are two types of hybrid DC system topologies:one is the parallel connection of LCC converter stations and MMC converter stations,and the other is the series connection of LCC and MMC converter stations within a single *** hybrid DC transmission system faces broad application prospects and development potential in large-scale clean energy integration across regions and the construction of a new power system dominated by new energy sources in *** paper first analyzes the system forms and topological characteristics of hybrid DC transmission,introducing the forms and topological characteristics of converter-level hybrid DC transmission systems and system-level hybrid DC transmission ***,it analyzes the operating characteristics of LCC and MMC inverter-level hybrid DC transmission systems,provides insights into the transient stability of hybrid DC transmission systems,and typical fault ride-through control ***,it summarizes the networking characteristics of the LCC-MMC series within the converter station hybrid DC transmission system,studies the transient characteristics and fault ridethrough control strategies under different fault types for the LCC-MMC series in the receiving-end converter station,and investigates the transient characteristics and fault ride-through control strategies under different fault types for the LCC-MMC series in the sending-end converter station.

关键词： Hybrid DC transmission Transient stability Configuration Control system

Coordinated Robust PiD-based Damping Control of Permanent Magnet Synchronous Generators for Low-frequency Oscillations Considering Power System Operational Uncertainties

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1042-1051页

作者： Rehan Sadiq Zhen Wang chi Yung Chung Deqiang Gan Cunzhi Tong College of Electrical Engineering Zhejiang UniversityHangzhou 310058China The Hong Kong Polytechnic University Hong KongChina State Grid Zhejiang Electric Power Company Hangzhou 310007China

in recent years, with the growth of wind energy resources,the capability of wind farms to damp low-frequency oscillations(LFOs) has provided a notable advantage for the stabilityenhancement of the modern power grid. Meanwhile, owingto variations in the power system operating point (OP), thedamping characteristics of LFOs may be affected adversely. inthis respect, this paper presents a coordinated robust proportional-integral-derivative (PiD) based damping control approachfor permanent magnet synchronous generators (PMSGs)to effectively stabilize LFOs, while considering power system operationaluncertainties in the form of a polytopic model constructedby linearizing the power system under a given set ofOPs. The proposed approach works by modulating the DC-linkvoltage control loop of the grid-side converter (GSC) via a supplementaryPiD controller, which is synthesized by transformingthe design problem into H-infinity static output feedback(SOF) control methodology. The solution of H-infinity SOF controlproblem involves satisfying linear matrix inequality (LMi)constraints based on the parameter-dependent Lyapunov functionto ensure asymptotic stability such that the minimal H-infinityperformance objective is simultaneously accomplished forthe entire polytope. The coordinated damping controllers forthe multiple wind farms are then designed sequentially by usingthe proposed approach. Eigenvalue analysis confirms the improveddamping characteristics of the closed-loop system forseveral representative OPs. Afterward, the simulation results, includingthe performance comparison with existing approaches,validate the higher robustness of the proposed approach for awide range of operating scenarios.

关键词： Permanent magnet synchronous generator(PMSG) low-frequency oscillation(LFO) proportional-integralderivative(PiD) robust control H-infinity static output feed-back control linear matrix inequality(LMi)

Space debris environment engineering model 2019:Algorithms improvement and comparison with ORDEM 3.1 and MASTER-8

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chinese Journal of Aeronautics 2024年第5期37卷 392-409页

作者： Yuyan LiU Runqiang chi Baojun PANG HU Diqi Wuxiong CAO Dongfang WANG School of Astronautics Harbin Institute of TechnologyHarbin 150001China College of Safety Science&Engineering Civil Aviation University of ChinaTianjin 300300China

As an essential tool for realistic description of the current or future debris environment,the Space Debris Environment Engineering Model(SDEEM)has been developed to provide support for risk assessment of *** contrast with SDEEM2015,SDEEM2019,the latest version,extends the orbital range from the Low Earth Orbit(LEO)to Geosynchronous Orbit(GEO)for the years *** this paper,improved modeling algorithms used by SDEEM2019 in propagating simulation,spatial density distribution,and spacecraft flux evaluation are *** debris fluxes of SDEEM2019 are compared with those of three typical models,i.e.,SDEEM2015,Orbital Debris Engineering Model 3.1(ORDEM 3.1),and Meteoroid and Space Debris Terrestrial Environment Reference(MASTER-8),in terms of two assessment *** orbital cases,including the Geostationary Transfer Orbit(GTO),Sun-Synchronous Orbit(SSO)and international Space Station(iSS)orbit,are selected for the spacecraft assessment mode,and the LEO region is selected for the spatial density assessment *** analysis indicates that compared with previous algorithms,the variable step-size orbital propagating algorithm based on semi-major axis control is more precise,the spatial density algorithm based on the second zonal harmonic of the non-spherical Earth gravity(J_(2))is more applicable,and the result of the position-centered spacecraft flux algorithm is more *** comparison shows that SDEEM2019 and MASTER-8 have consistent trends due to similar modeling processes,while the differences between SDEEM2019 and ORDEM 3.1 are mainly caused by different modeling approaches for uncatalogued debris.

关键词： SDEEM2019 Space debris propagating algorithm Spatial density algorithm ORDEM 3.1 MASTER-8

Cobalt-nitrogen co-doped porous carbon sphere as highly efficient catalyst for liquid-phase cyclohexane oxidation with molecular oxygen and the active sites investigation

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 101-112页

作者： Lei Chen Yuan Sun Jinshan chi Wei Xiong Pingle Liu Fang Hao College of Chemical Engineering National&Local United Engineering Research Centre for Chemical Process Simulation and IntensificationXiangtan UniversityXiangtan411105China

The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol(KA oil)is a challenging issue in the chemical *** present the industrial conversion of cyclohexane to cyclohexanone and cyclohexanol is normally controlled at less than 5%***,the development of highly active and stable catalysts for the aerobic oxidation of cyclohexane is necessary to overcome this low-efficiency ***,we have developed a cobalt-nitrogen co-doped porous sphere catalyst,Co-NC-x(x is the Zn/Co molar ratio,where x=0,0.5,1,2,and 4)by pyrolyzing resorcinol-formaldehyde resin *** achieved 88.28%cyclohexanone and cyclohexanol selectivity and a cyclohexane conversion of 8.88%under *** results showed that the introduction of zinc effectively alleviated the aggregation of Co nanoparticles and optimized the structural properties of the *** addition,Co0 and pyridinic-N are proposed to be the possible active species,and their proportion efficiently increased in the presence of Zn^(2+)*** this study,we developed a novel strategy to design highly active catalysts for cyclohexane oxidation.

关键词： KA oil production cyclohexane selective oxidation cobalt-nitrogen co-doped porous carbon spheres metal-organic framework