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Applied Mathematics and Mechanics(English Edition) 2023年第6期44卷 961-980页

作者： Lan JIANG Jie WU Liming YANG Hao Dong State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Aerodynamics Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China

A high-order gas kinetic flux solver(GKFS)is presented for simulating inviscid compressible flows.The weighted essentially non-oscillatory(WENO)scheme on a uniform mesh in the finite volume formulation is combined with the circular function-based GKFS(C-GKFS)to capture more details of the flow fields with fewer grids.Different from most of the current GKFSs,which are constructed based on the Maxwellian distribution function or its equivalent form,the C-GKFS simplifies the Maxwellian distribution function into the circular function,which ensures that the Euler or Navier-Stokes equations can be recovered correctly.This improves the efficiency of the GKFS and reduces its complexity to facilitate the practical application of engineering.Several benchmark cases are simulated,and good agreement can be obtained in comparison with the references,which demonstrates that the high-order C-GKFS can achieve the desired accuracy.

关键词： circular function-based gas kinetic flux solver(C-GKFS) weighted essentially non-oscillatory(WENO)scheme compressible flow finite volume method

Ori-Finder 2022:A Comprehensive Web Server for Prediction and Analysis of Bacterial Replication Origins

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Genomics, Proteomics & Bioinformatics 2022年第6期20卷 1207-1213页

作者： Mei-Jing dong hao Luo Feng Gao Department of Physics School of ScienceTianjin UniversityTianjin 300072China Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering(Ministry of Education) Tianjin UniversityTianjin 300072China SynBio Research Platform Collaborative Innovation Center of Chemical Science and Engineering(Tianjin)Tianjin 300072China

The replication of DNA is a complex biological process that is essential for life.Bacterial DNA replication is initiated at genomic loci referred to as replication origins(oriCs).Integrating the Z-curve method,DnaA box distribution,and comparative genomic analysis,we developed a web server to predict bacterial oriCs in 2008 called Ori-Finder,which is helpful to clarify the characteristics of bacterial oriCs.The oriCs of hundreds of sequenced bacterial genomes have been annotated in the genome reports using Ori-Finder and the predicted results have been deposited in DoriC,a manually curated database of oriCs.This has facilitated large-scale data mining of functional elements in oriCs and strand-biased analysis.Here,we describe Ori-Finder 2022 with updated prediction framework,interactive visualization module,new analysis module,and user-friendly interface.More species-specific indicator genes and functional elements of oriCs are integrated into the updated framework,which has also been redesigned to predict oriCs in draft genomes.The interactive visualization module displays more genomic information related to oriCs and their functional elements.The analysis module includes regulatory protein annotation,repeat sequence discovery,homologous oriC search,and strand-biased analyses.The redesigned interface provides additional customization options for oriC prediction.Ori-Finder 2022 is freely available at http://***/Ori-Finder/and https://***/Ori-Finder/.

关键词： Bacteria DNA replication Replication origin Z-curve DnaA-trio

以人为本的创新实验——Crossboundaries创始人董灏访谈

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建筑师 2022年第1期 129-137页

作者：孙德龙董灏天津大学建筑学院 Crossboundaries

建筑师董灏作为Crossboundaries事务所联合创始人,近年来在教育建筑等领域逐渐获得关注,"空间塑人"是其重要的设计理念。2020年9月28日,笔者对董灏进行了深度访谈。在本次访谈中,董灏着重阐述了在广泛的社会背景下,建筑师如何定位自身... 详细信息

建筑师董灏作为Crossboundaries事务所联合创始人,近年来在教育建筑等领域逐渐获得关注,"空间塑人"是其重要的设计理念。2020年9月28日,笔者对董灏进行了深度访谈。在本次访谈中,董灏着重阐述了在广泛的社会背景下,建筑师如何定位自身角色。在实践中,通过对使用者的关怀和引导,拥抱新技术并与社会积极沟通,董灏展现了建筑师在未来社会中角色定位的多重可能性。

关键词：跨界空间塑人教育建筑批判性思维

Coating zirconium oxide-nanocomposite with humic acid for recovery of mercury and chromium in hazardous waste of chemical oxygen demand test

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Journal of Environmental Sciences 2023年第4期126卷 40-47页

作者： Yujian Lai Liteng hao Lijie dong Sujuan Yu Jingfu Liu State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China China Testing&Certification International Group Co. Ltd.Beijing 100024China School of Environment Hangzhou Institute for Advanced StudyUCASHangzhou 310024China Division of Chemical Metrology and Analytical Chemistry National Institute of MetrologyBeijing 100029China Institute of Environment and Health Jianghan UniversityWuhan 430056China

Hazardous waste of chemical oxygen demand (COD) test (HWCOD) is one of the most common laboratory wastewaters,containing large amounts of H_(2)SO_(4)and highly toxic Cr^(3+)and Hg^(2+).Current treatment methods suffered from incomplete removal of Cr^(3+)and high-cost.Herein,a humic acid-coated zirconium oxide-resin nanocomposite (HA-HZO-201) was fabricated for efficient recovery of Cr^(3+)and Hg^(2+)in HWCOD.The synthesized HA-HZO-201 shows excellent tolerance to wide p H range (1–5) and high salinity (3.5 mol/L Na Cl),as well as adsorption capacity for Cr^(3+)(37.5 mg/g) and Hg^(2+)(121.3 mg/g).After treating with HA-HZO-201 by using a fixed-bed adsorption procedure,the final Cr^(3+)and Hg^(2+)concentrations in HWCOD decreased to 0.28 and 0.02 mg/L,respectively.In addition,the HA-HZO-201 can be regenerated by desorption and recovery of Cr^(3+)and Hg^(2+)using HNO_(3)and thiourea as eluents,respectively.After 5 cycles of adsorption/desorption,the removal efficiencies still reach up to86.0%for Cr^(3+)and 89.7%for Hg^(2+),indicating an excellent regeneration of HA-HZO-201.We hope this work open new opportunities for treatment of HWCODwith high-efficiency and low-cost.

关键词： COD analysis wastewater Nanocomposite ZrO_(2) Resin Humic acid

Experimental study of non-uniform bubbles in a plume

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Journal of Hydrodynamics 2022年第1期34卷 116-124页

作者： Xin-wei Ye hao-jie Zhou dong-dong Shao Xiao-jing Niu State Key Laboratory of Hydroscience and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing100084China State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing100875China

The bubble plume is an important flow phenomenon, ubiquitous in many fields. The non-uniform bubbles in a plume are often simply considered as uniform and moving with a same slip velocity in an integral model. This study aims to have a better understanding of the behavior of the non-uniform bubbles in a plume. A set of experiments are conducted in a transparent water tank, in which the air plumes are generated through different injectors to vary the spectrum of the bubble size. The shadow images of the bubbles are simultaneously recorded with the illumination of a plane backlight. The algorithm used in the image analysis for tracing the bubbles is a newly developed multi-frame method based on the predictor-corrector method, with a good accuracy in estimating the size and the velocity of the overlapped bubbles based on the bubble shadow images. The bubbles are divided into several groups by their equivalent diameters with an interval of 0.5 mm. The spectrums of the bubble size and the void fraction are measured. It is found that the bubbles of different sizes show different dynamics features, resulting in a difference in the radial distribution. It is shown that the large bubbles gather in the center of the plume, while the medium bubbles spread the widest and even wider than the small bubbles. The difference can be explained by the effects of the transverse lift force and the amplitude of the bubble oscillation.

关键词： Bubble plume experiment image analysis bubble size transverse lift force

Development and preliminary results of a large-pixel two-layer LaBr_(3) Compton camera prototype

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Nuclear Science and Techniques 2023年第8期34卷 100-114页

作者： Ming-Hao Dong Zhi-Yang Yao Yong-Shun Xiao Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging(Tsinghua University) Ministry of EducationBeijing 100084China

Lanthanum bromide(LaBr_(3))crystal has a high energy resolution and time resolution and has been used in Compton cameras(CCs)over the past few decades.However,LaBr_(3) crystal arrays are difficult to process because LaBr_(3) is easy to crack and break;thus,few LaBr_(3)-based CC prototypes have been built.In this study,we designed and fabricated a large-pixel LaBr_(3) CC prototype and evaluated its performance with regard to position,energy,and angular resolution.We used two 10×10 LaBr_(3) crystal arrays with a pixel size of 5 mm×5 mm,silicon photomultipliers(SiPMs),and corresponding decoding circuits to construct our prototype.Additionally,a framework based on a Voronoi diagram and a lookup table was developed for list-mode projection data acquisition.Monte Carlo(MC)simulations based on Geant4 and experiments were conducted to evaluate the performance of our CC prototype.The lateral position resolution was 5 mm,and the maximum deviation in the depth direction was 2.5 and 5 mm for the scatterer and absorber,respectively.The corresponding measured energy resolu-tions were 7.65%and 8.44%,respectively,at 511 keV.The experimental results of ^(137)Cs point-like sources were consistent with the MC simulation results with regard to the spatial positions and full widths at half maximum(FWHMs).The angular resolution of the fabricated prototype was approximately 6°when a point-like ^(137)Cs source was centrally placed at a distance of 5 cm from the scatterer.We proposed and investigated a large-pixel LaBr_(3) CC for the first time and verified its feasibility for use in accurate spatial positioning of radiative sources with a high angular resolution.The proposed CC can satisfy the requirements of radiative source imaging and positioning in the nuclear industry and medical applications.

关键词： Compton camera Large pixel Gamma camera LaBr_(3)detector Prototype evaluation

A Degree Condition for Graphs Having All(a,b)-parity Factors

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 656-664页

作者： hao-dong LIU Hong-liang LU School of Mathematics and Statistics Xi'an Jiaotong UniversityXi'an 710049China

Let a and b be positive integers such that a≤b and a≡b(mod 2).We say that G has all(a,b)-parity factors if G has an h-factor for every function h:V(G)→{a,a+2,…,b-2,b} with b|V(G)| even and h(v)≡b(mod 2) for all v∈V(G).In this paper,we prove that every graph G with n≥2(b+1)(a+b) vertices has all(a,b)-parity factors if δ(G)≥(b^(2)-b)/a,and for any two nonadjacent vertices u,v ∈V(G),max{d_(G)(u),d_(G)(v)}≥bn/a+b.Moreover,we show that this result is best possible in some sense.

关键词： degree condition all(a,b)-factors

A Hybrid Level Set Optimization Design Method of Functionally Graded Cellular Structures Considering Connectivity

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Computers, Materials & Continua 2024年第4期79卷 1-18页

作者： Yan dong Kang Zhao Liang Gao hao Li The State Key Lab of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan430074China Institute of Systems Engineering China Academy of Engineering PhysicsMianyang621900China

With the continuous advancement in topology optimization and additive manufacturing(AM)technology,the capability to fabricate functionally graded materials and intricate cellular structures with spatially varying microstructures has grown significantly.However,a critical challenge is encountered in the design of these structures–the absence of robust interface connections between adjacent microstructures,potentially resulting in diminished efficiency or macroscopic failure.A Hybrid Level Set Method(HLSM)is proposed,specifically designed to enhance connectivity among non-uniform microstructures,contributing to the design of functionally graded cellular structures.The HLSM introduces a pioneering algorithm for effectively blending heterogeneous microstructure interfaces.Initially,an interpolation algorithm is presented to construct transition microstructures seamlessly connected on both sides.Subsequently,the algorithm enables the morphing of non-uniform unit cells to seamlessly adapt to interconnected adjacent microstructures.The method,seamlessly integrated into a multi-scale topology optimization framework using the level set method,exhibits its efficacy through numerical examples,showcasing its prowess in optimizing 2D and 3D functionally graded materials(FGM)and multi-scale topology optimization.In essence,the pressing issue of interface connections in complex structure design is not only addressed but also a robust methodology is introduced,substantiated by numerical evidence,advancing optimization capabilities in the realm of functionally graded materials and cellular structures.

关键词： Hybrid level set method functionally graded cellular structure connectivity interpolated transition optimization design

Ripple-based matrix modeling and cross-coupling effect analysis of double-input DC-DC Boost converters

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Science China(Technological Sciences) 2022年第8期65卷 1878-1890页

作者： ZHANG hao REN Han YI ChuanZhi dong DaChu State Key Lab of Electrical Insulation&Power Equipment School of Electrical EngineeringXi’an Jiaotong UniversityXi’an 710049China Bosch Automotive Product(Suzhou)Co.Ltd Suzhou 215000China Hangzhou Power Supply Company of State Grid Zhejiang Electric Power Co.Ltd Hangzhou 310000China

This paper deals with the modeling and cross-coupling effect analysis in double-input Boost converters with multiplex current control. A ripple-based multiplex current controlled matrix model is proposed to restore the system's high-frequency domain dynamics information and resolve the coexistence problem of the sample-and-hold effect in multiplex current controllers, which significantly improves the resolution of the conventional average model. Based on the proposed model, both sub-harmonic and low-frequency oscillations are identified in terms of stability analysis, and the inherent mechanism of these complicated nonlinear dynamic behavior is revealed, which not only illustrates the origin of the oscillations but also points out the dominant factors in diverse types of instability situation. Besides, cross-coupling effect analysis is performed to study the interaction between the input ports with the help of the Gershgorin band, and the mechanism of the special unbalanced oscillation phenomenon is revealed. Furthermore, the sensitivity analysis approach is used to identify the key parameters with respect to the cross-coupling effect, which provides more design-oriented knowledge for practical engineering. In addition, the benefits of the proposed model are further illustrated through a comparative analysis. Finally, these theoretical results are verified by experimental ones. These results are beneficial to the improvement of performance as well as the understanding of the cross-coupling effect of multi-input converters.

关键词： ripple-based matrix model cross-coupling effect multiplex current control multi-input converter Gershgorin band

Distributed optimization of electricity-Gas-Heat integrated energy system with multi-agent deep reinforcement learning

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Global Energy Interconnection 2022年第6期5卷 604-617页

作者： Lei dong Jing Wei hao Lin Xinying Wang School of Electric Engineering North China Electric Power UniversityChangping DistrictBeijing 102206P.R.China China Electric Power Research Institute Haidian DistrictBeijing 100192P.R.China

The coordinated optimization problem of the electricity-gas-heat integrated energy system(IES)has the characteristics of strong coupling,non-convexity,and nonlinearity.The centralized optimization method has a high cost of communication and complex modeling.Meanwhile,the traditional numerical iterative solution cannot deal with uncertainty and solution efficiency,which is difficult to apply online.For the coordinated optimization problem of the electricity-gas-heat IES in this study,we constructed a model for the distributed IES with a dynamic distribution factor and transformed the centralized optimization problem into a distributed optimization problem in the multi-agent reinforcement learning environment using multi-agent deep deterministic policy gradient.Introducing the dynamic distribution factor allows the system to consider the impact of changes in real-time supply and demand on system optimization,dynamically coordinating different energy sources for complementary utilization and effectively improving the system economy.Compared with centralized optimization,the distributed model with multiple decision centers can achieve similar results while easing the pressure on system communication.The proposed method considers the dual uncertainty of renewable energy and load in the training.Compared with the traditional iterative solution method,it can better cope with uncertainty and realize real-time decision making of the system,which is conducive to the online application.Finally,we verify the effectiveness of the proposed method using an example of an IES coupled with three energy hub agents.

关键词： Integrated energy system Multi-agent system Distributed optimization Multi-agent deep deterministic policy gradient Real-time optimization decision