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A Note on Directed Genera of Some Tournaments

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Acta Mathematicae Applicatae Sinica 2018年第3期34卷 478-484页

作者： jian-bing liu Rong-xia HAO Department of Mathematics Beijing Jiaotong University

An embedding of a digraph in an orientable surface is an embedding as the underlying graph and arcs in each region force a directed cycle. The directed genus is the minimum genus of surfaces in which the digraph can be directed embedded. Bonnington, Conder, Morton and McKenna [J. Cornbin. Theory Ser. B,85（2002） 1-20] gave the problem that which tournaments on n vertices have the directed genus [（n-3）（n-4）/12]the genus of Kn. In this paper, we use the current graph method to show that there exists a tournament, whichhas the directed genus[（n-3）（n-4）/12], on n vertices if and only if n = 3 or 7 （mod 12）.

关键词： digraph directed embedding directed genus surfaces

Chromosome-level genome assembly of the dotted gizzard shad(Konosirus punctatus) provides insights into its adaptive evolution

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Zoological Research 2022年第2期43卷 217-220页

作者： bing-jian liu Kun Zhang Shu-Fei Zhang Yi-Fan liu Jia-Sheng Li Ying Peng Xun Jin Yun-Peng Wang Si-Xu Zheng Li Gong Li-Qin liu Zhen-Ming Lu National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization Zhejiang Ocean UniversityZhoushanZhejiang 316022China Guangdong Provincial Key Laboratory of Fishery Ecology and Environment South China Sea Fisheries Research InstituteChinese Academy of Fisheries SciencesGuangzhouGuangdong 510300China National Engineering Research Center for Facilitated Marine Aquaculture Marine Science and Technology CollegeZhejiang Ocean UniversityZhoushanZhejiang 316022China

Konosirus punctatus is an economically important marine fishery resource and is widely distributed from the Indian to Pacific *** is a good non-model species for genetic studies on salinity and temperature ***,a high-... 详细信息

关键词： salinity Indian evolution

Study on tungsten sintering temperature field based on electromagnetic simulation and computational fluid dynamics

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Tungsten 2024年第2期6卷 355-366页

作者： Lu-Yan Wang Yue-Guang Yu jian-Xin Dong Kai-Ping Du Shan-Yu liu Cao-bing Li University of Science and Technology Beijing Beijing 100083China BGRIMM Technology Group Beijing 100160China China Iron&Steel Research Institute Group Beijing 100081China

In order to study the influence of various sintering variables more intuitively and clearly,electromagnetic field analysis and computational fl uid dynamics are used to analyze the infl uence of gas flow,heating power and other process parameters on the temperature range of medium-frequency sintering in this *** results indicate that the uniformity of temperature fi eld is determined by the gas flow rate and heating *** the heating power is 50 kW,the stable temperature drops about 10 K for every 1 m^(3)·h^(−1)increase of hydrogen *** peak value of the maximum temperature diff erence on the tungsten rods gradually increases with the increase of the hydrogen flow rate,and it appears slightly *** temperature distribution of tungsten rods in furnace is similar with diff erent hydrogen flow *** the same time,the closer to the furnace wall,the higher the temperature of the tungsten *** temperature diff erence between tungsten rods mainly occurred within 1 h after the beginning of *** the heating power can improve the stable temperature,but has little eff ect on the heating *** heating power can increase the peak value of the maximum temperature diff erence on the tungsten rods,but has little eff ect on the occurrence time of the peak value of the maximum temperature diff erence on the tungsten *** the heating power will increase the temperature diff erence of a single tungsten rod,but the temperature diff erence of a single tungsten rod never exceeds 65 *** study can be used to guide the process optimization *** with numerical simulation calculation,the sintering parameters with low energy consumption and high temperature uniformity can be quickly and eff ectively found,thus improving the microstructure and properties of sintered tungsten products.

关键词： Tungsten products Sintering Hydrogen flow rate Heating power

High-rate electrochemical H_(2)O_(2) production over multimetallic atom catalysts under acidic–neutral conditions

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Carbon Energy 2024年第1期6卷 44-62页

作者： Yueyu Tong Jiaxin liu bing-jian Su Jenh-Yih Juang Feng Hou Lichang Yin Shi Xue Dou Ji Liang Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education School of Materials Science and EngineeringTianjin UniversityTianjinChina Institute for Superconducting and Electronic Materials University of WollongongInnovation CampusNorth WollongongNew South WalesAustralia Department of Electrophysics National Chiao Tung UniversityHsinchuTaiwanChina Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyangLiaoningChina Institute of Energy Materials Science University of Shanghai for Science and TechnologyShanghaiChina

Hydrogen peroxide(H_(2)O_(2))production by the electrochemical 2-electron oxygen reduction reaction(2e−ORR)is a promising alternative to the energy-intensive anthraquinone process,and single-atom electrocatalysts show the unique capability of high selectivity toward 2e−ORR against the 4e−*** extremely low surface density of the single-atom sites and the inflexibility in manipulating their geometric/electronic configurations,however,compromise the H_(2)O_(2) yield and impede further performance ***,we construct a family of multiatom catalysts(MACs),on which two or three single atoms are closely coordinated to form high-density active sites that are versatile in their atomic configurations for optimal adsorption of essential*OOH *** them,the Cox–Ni MAC presents excellent electrocatalytic performance for 2e−ORR,in terms of its exceptionally high H_(2)O_(2) yield in acidic electrolytes(28.96 mol L^(−1) gcat.^(−1) h^(−1))and high selectivity under acidic to neutral conditions in a wide potential region(>80%,0–0.7 V).Operando X-ray absorption and density functional theory analyses jointly unveil its unique trimetallic Co2NiN8 configuration,which efficiently induces an appropriate Ni–d orbital filling and modulates the*OOH adsorption,together boosting the electrocatalytic 2e−ORR *** work thus provides a new MAC strategy for tuning the geometric/electronic structure of active sites for 2e−ORR and other potential electrochemical processes.

关键词： hydrogen peroxide production multiatom catalysts operando X-ray adsorption spectrum reaction mechanism tendency structure-property relation

Development characteristics and controlling factors of fractures in lacustrine shale and their geological significance for evaluating shale oil sweet spots in the third member of the Shahejie Formation in the Qikou Sag, Bohai Bay Basin

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Petroleum Science 2024年第2期21卷 791-805页

作者： Xu Zeng Tao Yang jian-Wei Feng Cong-Sheng Bian Ming Guan Wei liu bing-Cheng Guo Jin Dong Research Institute of Petroleum Exploration and Development China National Petroleum CorporationBeijing100083China College of Geosciences China University of Petroleum(Beijing)Beijing102249China Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China School of Earth Sciences China University of PetroleumQingdao266400ShandongChina

Natural fractures are critical for shale oil and gas enrichment and development. Due to the extremely high heterogeneity of shale, the factors controlling the formation of internal fractures, especially horizontal fractures, remain controversial. In this study, we integrate thin section analysis and microcomputed tomography(CT) data from several lacustrine shale samples from the third member(Es3) of the Shahejie Formation, Qikou Sag, Bohai Bay Basin, to assess the fractures in detail. The goal is to reveal the development characteristics, controlling factors, and geological significance for evaluating sweet spots in a shale oil play. The fractures in the Es3contain high-angle structural and horizontal bed-parallel fractures that are mostly shear and extensional. Various factors influence fracture development,including lithofacies, mineral composition, organic matter content, and the number of laminae. Structural fractures occur predominantly in siltstone, whereas bed-parallel fractures are abundant in laminated shale and layered mudstone. A higher quartz content results in higher shale brittleness, causing fractures, whereas the transformation between clay minerals contributes to the development of bedparallel fractures. Excess pore pressure due to hydrocarbon generation and expulsion during thermal advance can cause the formation of bed-parallel fractures. The density of the bed-parallel and structural fractures increases with the lamina density, and the bed-parallel fractures are more sensitive to the number of laminae. The fractures are critical storage spaces and flow conduits and are indicative of sweet spots. The laminated shale in the Es3with a high organic matter content contains natural fractures and is an organic-rich, liquid-rich, self-sourced shale play. Conversely, the siltstone, massive mudstone, and argillaceous carbonate lithofacies contain lower amounts of organic matter and do not have bed-parallel fractures. However, good reservoirs can form in th

关键词： Fractures Development characteristics Controlling factors Shale oil Sweet spot

Automated,economical,and environmentally-friendly asphalt mix design based on machine learning and multi-objective grey wolf optimization

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 381-405页

作者： jian liu Fangyu liu Linbing Wang Department of Civil and Environmental Engineering Virginia Polytechnic Institute and State UniversityBlacksburgVA 24061USA School of Environmental CivilAgricultural and Mechanical EngineeringUniversity of GeorgiaAthensGA 30602USA Illinois Center for Transportation Department of Civil and Environmental EngineeringUniversity of Illinois Urbana-ChampaignUrbanaIL 61801USA

The increasing impact of the greenhouse effect on ecosystems is prompting transportation agencies to seek methods for reducing CO_(2)emissions during pavement construction and ***,the laboratory mix design process,which involves selecting aggregate gradation and binder content,is time-consuming and *** accelerate the traditional mix design procedure,this study presented a mix design procedure that can automatically determine gradation and binder content based on machine learning(ML)and a meta-heuristic ***,ML approaches were employed to model the relationship between volumetric properties(mixture bulk specific gravity(Gmb)and air void(VV))and both mixture component properties and mixture proportion,based on a dataset collected from literature with 660 mixture *** with the prediction of ML models and the modified multi-objective grey wolf optimization(MOGWO)algorithm,an automatic asphalt mix design was proposed to pursue three goals,including VV,cost,and CO_(2)*** results indicated that least squares support vector regression(LSSVR)and e Xtreme gradient boosting(XGBoost)achieved the highest prediction accuracies(correlation coefficient:0.92 for VV and 0.96 for Gmb).The MOGWO algorithm successfully found the 26 optimal mix designs for the case of VV *** ***_(2)*** to the traditional laboratory design,the optimal mixture with VV of4%achieves a cost saving of 2.46%and a reduction of 4.03%in carbon *** volumetric properties of the mixtures output by the approach also align closely with values measured in a laboratory.

关键词： Asphalt mix design Machine learning MOGWO CO_(2)emission Volumetric properties

An Industrial Intrusion Detection Method Based on Hybrid Convolutional Neural Networks with Improved TCN

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Computers, Materials & Continua 2024年第1期78卷 411-433页

作者： Zhihua liu Shengquan liu jian Zhang College of Computer Science and Technology Xinjiang UniversityXinjiang Uygur Autonomous RegoinUrumqi830000China

Network intrusion detection systems(NIDS)based on deep learning have continued to make significant ***,the following challenges remain:on the one hand,simply applying only Temporal Convolutional Networks(TCNs)can lead to models that ignore the impact of network traffic features at different scales on the detection *** the other hand,some intrusion detection methods considermulti-scale information of traffic data,but considering only forward network traffic information can lead to deficiencies in capturing multi-scale temporal *** address both of these issues,we propose a hybrid Convolutional Neural Network that supports a multi-output strategy(BONUS)for industrial internet intrusion ***,we create a multiscale Temporal Convolutional Network by stacking TCN of different scales to capture the multiscale information of network ***,we propose a bi-directional structure and dynamically set the weights to fuse the forward and backward contextual information of network traffic at each scale to enhance the model’s performance in capturing the multi-scale temporal features of network *** addition,we introduce a gated network for each of the two branches in the proposed method to assist the model in learning the feature representation of each *** experiments reveal the effectiveness of the proposed approach on two publicly available traffic intrusion detection datasets named UNSW-NB15 and NSL-KDD with F1 score of 85.03% and 99.31%,respectively,which also validates the effectiveness of enhancing the model’s ability to capture multi-scale temporal features of traffic data on detection performance.

关键词： Intrusion detection industrial internet channel spatial attention multiscale features dynamic fusion multi-output learning strategy

A review of reservoir damage during hydraulic fracturing of deep and ultra-deep reservoirs

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Petroleum Science 2024年第1期21卷 384-409页

作者： Kun Zhang Xiong-Fei liu Dao-bing Wang Bo Zheng Tun-Hao Chen Qing Wang Hao Bai Er-Dong Yao Fu-jian Zhou National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum-BeijingBeijing102249China School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing102617China Tuha Downhole Operation Company CNPC Xibu Drilling Engineering Company LimitedShanshan838200XinjiangChina

Deep and ultra-deep reservoirs have gradually become the primary focus of hydrocarbon exploration as a result of a series of significant discoveries in deep hydrocarbon exploration *** reservoirs present unique challenges due to their deep burial depth(4500-8882 m),low matrix permeability,complex crustal stress conditions,high temperature and pressure(HTHP,150-200℃,105-155 MPa),coupled with high salinity of formation ***,the costs associated with their exploitation and development are exceptionally *** deep and ultra-deep reservoirs,hydraulic fracturing is commonly used to achieve high and stable *** hydraulic fracturing,a substantial volume of fluid is injected into the ***,statistical analysis reveals that the flowback rate is typically less than 30%,leaving the majority of the fluid trapped within the ***,hydraulic fracturing in deep reservoirs not only enhances the reservoir permeability by creating artificial fractures but also damages reservoirs due to the fracturing fluids *** challenging“three-high”environment of a deep reservoir,characterized by high temperature,high pressure,and high salinity,exacerbates conventional forms of damage,including water sensitivity,retention of fracturing fluids,rock creep,and proppant *** addition,specific damage mechanisms come into play,such as fracturing fluid decomposition at elevated temperatures and proppant diagenetic reactions at HTHP ***,the foremost concern in deep oil and gas development lies in effectively assessing the damage inflicted on these reservoirs by hydraulic fracturing,comprehending the underlying mechanisms,and selecting appropriate ***'s noteworthy that the majority of existing studies on reservoir damage primarily focus on conventional reservoirs,with limited attention given to deep reservoirs and a lack of systematic *** light of this,our approach entails initially summarizin

关键词： Artificial fracture Deep and ultra-deep reservoir Fracture conductivity Fracturing fluid Hydraulic fracturing Reservoir damage

Self-assembled high-entropy nitride multilayer coating

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Rare Metals 2024年第6期43卷 2876-2883页

作者： Xiang-Yu Zhang Yan liu Vasiliy Pelenovich Xiao-Mei Zeng Jie liu Qiang Wan Alexander Pogrebnjak Long-jian Xue Zhi-Wen Chen Yan Lei bing Yang School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China Hubei JiuFengShan Future Science and Technology Laboratory Wuhan 420000China Institute of Technological Sciences of Wuhan University Wuhan 430072China Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration Wuhan UniversityWuhan 430072China College of Engineering Huazhong Agricultural UniversityWuhan 430070China Sumy State University Sumy 40007Ukraine Institute of Materials Science Slovak University of Technology in BratislavaJána Bottu2591724 TrnavaSlovak Republic Shenzhen Research Institute of Wuhan University Shenzhen 518057China

The development of advanced materials and construction of multilayer structure contribute to enhancing the performance of protective coatings,further improving the industrial productivity and conserving *** this paper,the self-assembled high-entropy nitride(HEN)AlCrNbSiTiN multilayer coating was designed by harnessing the plasma distribution characteristics and depos-ited by arc ion plating using single target.

关键词： coating energy multilayer