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Overview of computation strategies on the dispersion analysis for explicit finite difference solution of acoustic wave equation

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Petroleum Science 2024年第4期21卷 2311-2328页

作者： Jian-ping Huang Wei-Ting Peng Ji-dong Yang Lu-feng Lou School of Geosciences China University of Petroleum (East China) Pilot National Laboratory for Marine Science and Technology (Qingdao)

Finite-difference(FD) method is the most extensively employed numerical modeling technique. Nevertheless, when using the FD method to simulate the seismic wave propagation, the large spatial or temporal sampling interval can lead to dispersion errors and numerical instability. In the FD scheme, the key factor in determining both dispersion errors and stability is the selection of the FD weights. Thus,How to obtain appropriate FD weights to guarantee a stable numerical modeling process with minimum dispersion error is critical. The FD weights computation strategies can be classified into three types based on different computational ideologies, window function strategy, optimization strategy, and Taylor expansion strategy. In this paper, we provide a comprehensive overview of these three strategies by presenting their fundamental theories. We conduct a set of comparative analyses of their strengths and weaknesses through various analysis tests and numerical modelings. According to these comparisons, we provide two potential research directions of this field: Firstly, the development of a computational strategy for FD weights that enhances stability; Secondly, obtaining FD weights that exhibit a wide bandwidth while minimizing dispersion errors.

关键词： Finite-difference scheme FD coefficients Dispersion error Forward modeling Numerical simulation

Dissection of No.13 lymph node in radical gastrectomy for gastric carcinoma

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World Journal of Gastroenterology 2008年第6期14卷 936-938页

作者： Ding-feng Shen Da-Wei Chen Zhi-Wei Quan ping dong Xue-feng Wang Hai-Zhou Xu Ming-Lin Zhao Lei Chen Department of General Surgery Shanghai Xinhua Hospital School of Medicine Shanghai Jiaotong University Shanghai 200092 China

AIM: To evaluate the feasibility and safety of No. 13 lymphadenectomy in radical gastrectomy for gastric carcinoma. METHODS: Medical records of the patients undergone No. 13 lymph node dissection during D2 gastrectomy for gastric carcinoma, were reviewed from March 2003 to May 2007. RESULTS: One hundred and fifty-eight patients underwent No. 13 lymph node dissection for D2 gastric carcinoma, of them, 4 (2.53%) were found to have metastasis in No. 13 lymph node. Metastasis to No. 12 lymph node was detected in 6 patients and 4 of them had positive No. 13 lymph node. The operative morbidity except for wound infection was 15.19% (24/158), and hospital death rate was 1.27% (2/158). No obstructive jaundice caused by No. 13 lymph node metastasis after No. 13 lymph node dissection in radical gastrectomy for gastric carcinoma was detected during the follow-up study to end of January 2007. CONCLUSION: Dissection of No. 13 lymph node in D2 gastrectomy for gastric carcinoma is safe with a low morbidity and mortality rate. Further study is needed to explore its long-term effect.

关键词： Gastric carcinoma Lymphadenectomy Gastric carcinoma No. 13 lymph node

Development and performance evaluation of high temperature resistant strong adsorption rigid blocking agent

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Petroleum Science 2024年第4期21卷 2650-2662页

作者： Zhe Xu Jin-Sheng Sun Jing-ping Liu Kai-He Lv Xiao-dong dong Zong-Lun Wang Tai-feng Zhang Yuan-Wei Sun Zhi-Wen Dai School of Petroleum Engineering China University of Petroleum (East China) CNPC Engineering Technology R&D Company Limited

As drilling wells continue to move into deep ultra-deep layers, the requirements for temperature resistance of drilling fluid treatments are getting higher and higher. Among them, blocking agent, as one of the key treatment agents, has also become a hot spot of research. In this study, a high temperature resistant strong adsorption rigid blocking agent(QW-1) was prepared using KH570 modified silica,acrylamide(AM) and allyltrimethylammonium chloride(TMAAC). QW-1 has good thermal stability,average particle size of 1.46 μm, water contact angle of 10.5., has a strong hydrophilicity, can be well dispersed in water. The experimental results showed that when 2 wt% QW-1 was added to recipe A(4 wt% bentonite slurry+0.5 wt% DSP-1(filtration loss depressant)), the API filtration loss decreased from 7.8to 6.4 m L. After aging at 240.C, the API loss of filtration was reduced from 21 to 14 m L, which has certain performance of high temperature loss of filtration. At the same time, it is effective in sealing 80-100mesh and 100-120 mesh sand beds as well as 3 and 5 μm ceramic sand discs. Under the same conditions,the blocking performance was superior to silica(5 μm) and calcium carbonate(2.6 μm). In addition, the mechanism of action of QW-1 was further investigated. The results show that QW-1 with amide and quaternary ammonium groups on the molecular chain can be adsorbed onto the surface of clay particles through hydrogen bonding and electrostatic interaction to form a dense blocking layer, thus preventing further intrusion of drilling fluid into the formation.

关键词： High adsorption Rigid microsphere High temperature resistance Blocking performance

Compositionally graded high-voltage P2-type cathode with superior structural stability and redox kinetics for advanced Na-ion batteries

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Nano Research 2024年第4期17卷 2755-2762页

作者： Peiyu Hou Mohan dong Zhenbo Sun feng Li School of Physics and Technology University of JinanJinan 250022China

Layered P2-type cathodes with high voltage,large capacity,and easy synthesis show great potential for developing sodium(Na)-ion batteries(NIBs).However,the P2–O2 phase transition makes their structural degradation and the Na^(+)/vacancy ordering lowers their redox ***,we rationally propose a compositionally graded P2-type cathode,where nickel(Ni)and manganese(Mn)fractions decrease gradually,and cobalt(Co)content increases contiguously from the inside to the outside of a secondary *** these particles,the Ni/Mn-based compound delivers high capacity and high *** the surface of particles,the Co/Mn-based solid solution offers a stable buffer *** from these synergistic effects,this graded P2-type cathode shows the elimination of P2–O2 transformation even when charged to 4.4 V,which enables good structural stability,maintaining capacity retention reaching~80%within 300 ***,the Na^(+)/vacancy ordering superstructure is further suppressed,and the Na^(+)diffusion kinetics is significantly *** proposed graded structure with optimized chemical composition offers a new perspective for eliminating the unwanted phase transition and thus enhancing the electrochemistry of high-voltage layered cathodes for advanced NIBs.

关键词： Na-ion battery P2-type cathode composition regulation phase transition redox stability

Molecular Dynamics-Based Simulation of Polyethylene Pipe Degradation in High Temperature and High Pressure Conditions

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Fluid Dynamics & Materials Processing 2024年第9期20卷 2139-2161页

作者： Guowei feng Qing Li Yang Wang Nan Lin Sixi Zha Hang dong ping Chen Minjun Zheng School of Mechanical Engineering Xinjiang UniversityUrumqi830046China Xinjiang Yian Special Inspection Engineering Company Limited Urumqi830063China Xinjiang Uygur Autonomous Region Inspection Institute of Special Equipment Urumqi830000China Pressure Pipe Department China Special Equipment Inspection and Research InstituteBeijing100013China Tarim Oilfield Branch Company Korla841000China Yimai Cai Oil and Gas Management Area Tarim Oilfield Branch OfficeKorla841000China

High-density polyethylene(HDPE)pipes have gradually become the first choice for gas networks because of their excellent *** the use of pipes increases,there will unavoidably be a significant amount of waste generated when the pipes cease their operation life,which,if improperly handled,might result in major environmental contamination *** this study,the thermal degradation of polyethylene materials is simulated for different pressures(10,50,100,and 150 MPa)and temperatures(2300,2500,2700,and 2900 K)in the framework of Reactive Force Field(ReaxFF)molecular dynamics *** main gas products,density,energy,and the mean square displacement with temperature and pressure are also *** findings indicate that raising the temperature leads to an increase in the production of gas products,while changing the pressure has an impact on the direction in which the products are generated;the faster the temperature drops,the less dense the air;both temperature and pressure increase impact the system’s energy conversion or distribution mechanism,changing the system’s potential energy as well as its total energy;the rate at which molecules diffuse increases with temperature,and decreases with *** results of this investigation provide a theoretical basis for the development of the pyrolytic treatment of polyethylene waste materials.

关键词： ReaxFF MD high-density polyethylene degradation temperature pressure

A versatile model with three-dimensional triangular lattice for unconventional transport and various topological effects

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National Science Review 2024年第1期11卷 204-214页

作者： Jing-Yang You Gang Su Yuan ping feng Department of Physics National University of Singapore Kavli Institute for Theoretical Sciences and CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Centre for Advanced 2D Materials National University of Singapore

The finite Berry curvature in topological materials can induce many subtle phenomena, such as the anomalous Hall effect(AHE), spin Hall effect(SHE), anomalous Nernst effect(ANE), non-linear Hall effect(NLHE) and bulk photovoltaic effects. To explore these novel physics as well as their connection and coupling, a precise and effective model should be developed. Here, we propose such a versatile model—a 3D triangular lattice with alternating hopping parameters, which can yield various topological phases,including kagome bands, triply degenerate fermions, double Weyl semimetals and so on. We reveal that this special lattice can present unconventional transport due to its unique topological surface states and the aforementioned topological phenomena, such as AHE, ANE, NLHE and the topological photocurrent effect. In addition, we also provide a number of material candidates that have been synthesized experimentally with this lattice, and discuss two materials, including a non-magnetic triangular system for SHE, NLHE and the shift current, and a ferromagnetic triangular lattice for AHE and ANE. Our work provides an excellent platform, including both the model and materials, for the study of Berry-curvature-related physics.

关键词： three-dimensional triangular lattice different topological phases various topological effects Berry curvature

Impurity formation mechanism of silicon carbide crystals smelted by Acheson process

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Journal of Iron and Steel Research International 2024年第6期31卷 1367-1375页

作者： dong feng Hong-qiang Ru Xu-dong Luo Jie-gang You Ling Zhang School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) Institute of Advanced CeramicsSchool of Materials Science and EngineeringNortheastern UniversityShenyang 110819LiaoningChina Liaoning Institute of Science and Technology Benxi 117004LiaoningChina

In order to further promote the application of SiC refractories in modern steel metallurgy,the occurrence forms and formation mechanism of impurities in SiC crystals smelted by Acheson process were *** techniques of inductively coupled plasma-atomic emission spectrometry,X-ray diffraction,and scanning electron microscopy were combined to examine the types and occurrence forms of impurities in smelted SiC *** results showed that the main impurities in the SiC are free Si,free C,oxides(CaO·Al_(2)O_(3)·2SiO_(2),3Al_(2)O_(3)·2SiO_(2),CaO·SiO_(2) and SiO_(2))and alloy phases(Fe_(x)Si_(y),Fe_(x)Si_(y)Ti_(z) and Fe_(x)Al_(y)Si_(z)).The formation process of impurities during the smelting of SiC can be described as follows:At high temperature,the SiO_(2) and Fe,Ti related oxide impurities present in the raw materials are reduced to Si,Fe,and Ti metal *** the reduction process,the free Si,Fe_(x)Si_(y) and Fe_(x)Si_(y)Ti_(z) are precipitated from the melt during *** Si primarily exists in aggregated form within the SiC crystal,while the alloy phase is predominantly found at the interface between SiC and free Si,with Fe_(x)Si_(y)Ti_(z) embedded within *** the end of the cooling process,other impurity oxides such as Al_(2)O_(3),CaO,and some unreduced SiO_(2) solidify to form calcium-aluminum-silicate glass phases,predominantly located between SiC *** remaining C from the reaction is mainly dispersed as free C within the SiC crystal and at the interface between SiC and free Si.

关键词： Impurity element Formation mechanism Smelted SiC crystal SiC refractory Occurrence form

Comparative transcriptomic evidence of physiological changes and potential relationships in vertebrates under different dormancy states

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Zoological Research 2024年第2期45卷 341-354页

作者： Yu-Han Niu Li-Hong Guan Cheng Wang Hai-feng Jiang Guo-Gang Li Lian-dong Yang Shun-ping He State Key Laboratory of Freshwater Ecology and Biotechnology Institute of HydrobiologyChinese Academy of SciencesWuhanHubei 430072China College of Life Sciences Qinghai Normal UniversityXiningQinghai 810008China Academy of Plateau Science and Sustainability Qinghai Normal UniversityXiningQinghai 810016China Key Laboratory of Biodiversity Formation Mechanism and Comprehensive Utilization of the Qinghai-Tibet Plateau in Qinghai Province Qinghai Normal UniversityXiningQinghai 810008China College of Life Sciences and Technology Xinxiang Medical UniversityXinxiangHenan 453003China College of Animal Science and Technology Northwest A&F UniversityYanglingShaanxi 712100China

Dormancy represents a fascinating adaptive strategy for organisms to survive in unforgiving *** a period of dormancy,organisms often exhibit exceptional *** period is typically divided into hibernation and aestivation based on seasonal ***,the mechanisms by which organisms adapt to their environments during dormancy,as well as the potential relationships between different states of dormancy,deserve further ***,we selected Perccottus glenii and Protopterus annectens as the primary subjects to study hibernation and aestivation,*** on histological and transcriptomic analysis of multiple organs,we discovered that dormancy involved a coordinated functional response across *** analyses revealed noteworthy disparities between the two dormant species in their responses to extreme ***,similarities in gene expression patterns pertaining to energy metabolism,neural activity,and biosynthesis were noted during hibernation,suggesting a potential correlation between hibernation and *** further explore the relationship between these two phenomena,we analyzed other dormancy-capable species using data from publicly available *** comparative analysis revealed that most orthologous genes involved in metabolism,cell proliferation,and neural function exhibited consistent expression patterns during dormancy,indicating that the observed similarity between hibernation and aestivation may be attributable to convergent *** conclusion,this study enhances our comprehension of the dormancy phenomenon and offers new insights into the molecular mechanisms underpinning vertebrate dormancy.

关键词： Hibernation Aestivation Multi-organs Convergent evolution

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Self-optimized H-adsorption affinity of CuRu alloy cocatalysts towards efficient photocatalytic H_(2)evolution

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Journal of Materials Science & Technology 2024年第7期174卷 168-175页

作者： Meiya Wang ping Wang Xuefei Wang feng Chen Huogen Yu School of Chemistry Chemical Engineering and Life Sciencesand School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China Laboratory of Solar Fuel Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan 430078China

In addition to the electron transfer,the appropriate H-adsorption affinity of active centers on the metal cocatalyst surface is quite important for high hydrogen-production activity of cocatalyst-modified *** typical Cu and Ru metal cocatalysts clearly exhibit a weak Cu-H bond and a strong Ru-H bond,respectively,resulting in limited activity for photocatalytic H_(2)*** this work,an ingenious strategy of self-optimized H-adsorption affinity in CuRu alloy cocatalyst is developed to simultaneously reinforce the Cu-H bond and weaken the Ru-H bond by the intrinsic electron transfer from Cu to Ru *** CuRu alloy nanoparticles(2-3 nm)were deposited on the TiO_(2)surface to prepare CuRu/TiO_(2)through a one-step photoreduction *** tests exhibited that the highest H_(2)-production rate of CuRu/TiO_(2)photocatalyst reached up to 5.316 mmol h^(-1)g^(-1),which was 24.80,1.86,and 2.60 times higher than that of the TiO_(2),Cu/TiO_(2),and Ru/TiO_(2),*** on the characterization results and theoretical calculations,the CuRu alloy cocatalyst exhibits excellent self-optimized H-adsorption affinity via the spontaneous electron transfer from Cu to Ru atom,which can greatly accelerate the photocatalytic H_(2)-production rate of TiO_(2).This work provides a feasible idea for the self-optimized H-adsorption affinity of metal active sites in the photocatalytic H_(2)-generation field.

关键词： TiO_(2) CuRu alloy Cocatalyst Self-optimized H-adsorption affinity Photocatalytic H_(2)generation