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Thermal conductive proppant with self-suspension ability

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Petroleum Science 2023年第3期20卷 1742-1749页

作者： Guo-Qing Xu Xiu-Ping Lan si-si hao Kai-Yi Hu si-Meng Qi Li-Dong Geng Quan Xu Yang Zhou sinopec Key Laboratory of Drilling Completion and Fracturing of Shale Oil and Gas SINOPEC Research Institute of Petroleum Engineering Co.LtdBejing102249China State Key Laboratory of Petroleum Resources and Prospecting Bejing Key Laboratoryof Biogas Upgrading UtilizationHarvard SEAS-CUPB Joint Laboratory on Petroleum ScienceChina University of Petroleum(Beijing)Beijing102249China

The in situ mining technology is applied to the exploitation of medium-and low-maturity shale oil,which can use heaters to warm up the oil shale formations and pyrolyze the *** to the low thermal conductivity of oil shale,electric heaters need extra equipment to improve heat transfer *** this study,a thermally conductive proppant is fabricated by coating epoxy-resin and graphite on ceramic proppants for the first time,which could support the fracturing crack and transfer *** thermal conduction property of epoxy-resin and graphite coated proppants(EGPs)is 245%higher than that of uncoated proppants,which can transfer more heat to the oil shale formation and accelerate the conversion of *** adhesive property of EGPs is improved by 47.9%under the load force of 1500 nN,which prolongs the time for the fracture to *** summary,this novel proppant is expected to assist in-situ mining technology in the production of medium and low-maturity shale oil.

关键词： Exploitation of shaleoil In situ mining Technology Thermally conductive proppant Heat transfer

Degree Conditions for k-Hamiltonian[a,b]-factors

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Acta Mathematicae Applicatae sinica 2021年第2期37卷 232-239页

作者： Jie Wu si-zhong ZHOu School of Economic and management Jiangsu University of Science and TechnologyZhenjiang 212100China School of Science Jiangsu University of Science and TechnologyZhenjiang 212100China

Let a,b,k be nonnegative integers with 2≤a<b.A graph G is called a k-Hamiltonian graph if G-u contains a Hamiltonian cycle for any subset u?V(G)with|u|=***[a,b]-factor F of G is called a Hamiltonian[a,b]-factor if F ... 详细信息

Let a,b,k be nonnegative integers with 2≤ab.A graph G is called a k-Hamiltonian graph if G-u contains a Hamiltonian cycle for any subset u?V(G)with|u|=***[a,b]-factor F of G is called a Hamiltonian[a,b]-factor if F contains a Hamiltonian *** G-u admits a Hamiltonian[a,b]-factor for any subset u?V(G)with|u|=k,then we say that G has a k-Hamiltonian[a,b]-*** that G is a k-Hamiltonian graph of order n with n≥((a+b-4)(2 a+b+k-6))/(b-2)+k andδ(G)≥a+*** this paper,it is proved that G admits a k-Hamiltonian[a,b]-factor if max{dG(x),dG(y)}≥((a-2)n+(b-2)k)/(a+b-4)+2 for each pair of nonadjacent vertices x and y in G.

关键词： degree condition k-Hamiltonian graph k-Hamiltonian[a b]-factor

RMAC： A Reliable MAC Protocol Supporting Multicast for Wireless Ad Hoc Networks

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Journal of Computer Science & Technology 2005年第5期20卷 702-712页

作者： Wei-Sheng si Cheng-Zhi Li School of Software Dalian University of Technology P.R. China Department of Computer Science and Engineering University of Texas at Arlington U.S.A.

This paper presents a new reliable MAC protocol called “RMAC”supporting reliable multicast for wireless ad hoc networks. by utilizing the busy tones to realize the multicast reliability, RMAC has three novelties：（1） it uses a variablelength control frame to stipulate an order for the receivers to respond, thus solving the feedback collision problem; （2） it extends the usage of busy tone for preventing data frame collisions into the multicast scenario; and （3） it introduces a new usage of busy tone for acknowledging data frames positively. In addition, RMAC is generalized into a comprehensive MAC protocol that provides both reliable and unreliable services for all the three modes of communications： unicast, multicast, and broadcast, making it capable of supporting various upper-layer protocols. The evaluation shows that RMAC achieves high reliability with very limited overhead. RMAC is also compared with other reliable MAC protocols, showing that RMAC not only provides higher reliability but also involves lower cost.

关键词： wireless ad hoc network medium access control reliable multicast busy tone

Redox-active nanoparticles for inflammatory bowel disease

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Nano Research 2021年第8期14卷 2535-2557页

作者： Qinjuan Ren si Sun Xiao-Dong Zhang Department of Physics and Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology School of SciencesTianjin UniversityTianjin 300350China Tianjin Key Laboratory of brain Science and Neural Engineering Academy of Medical Engineering and Translational MedicineTianjin UniversityTianjin 300072China

Homeostasis of gut microbiota is extremely essential for maintaining nutrient metabolism and regulating immunological *** increasing evidence suggests that inflammatory bowel disease(IbD)is strongly associated with dysregulation of gut *** activated inflammation,excessive reactive oxygen species(ROS)and reactive nitrogen species(RNS)produced by inflammatory cells play a detrimental role in regulating IbD and gut ***/RNS cause damage to the surrounding tissues,including nutrient absorption disorders,intestinal dysmotility and barrier ***,ROS/RNS provide terminal electron receptors for anaerobic respiration and support the bloom of facultative anaerobes,eventually causing gut microbiota ***-active nanoparticles(NPs)with catalytic properties or enzyme-like activities can effectively scavenge ROS/RNS,and selectively target inflamed sites via ultrasmall size-mediated enhanced permeation and retention(EPR)effect,showing great potential to regulate IbD and maintain the homeostasis of gut *** addition,the widespread application of NPs in commercial products 1 has increased their accumulation in healthy organisms,and the biological effects on normal microbiota resulting from long-term exposure of NPs to gastrointestinal tract also need attention.

关键词： gut microbiota IbD ROS/RNS redox-active NPs

APPLICATION OF Ct-PARAMETER FOR CREEP-FATIGuE CRACK GROWTH WITH SLOW LOAD RIsiNG CONDITION

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Acta Metallurgica sinica(English Letters) 1999年第1期12卷 22-30页

作者： Lee, J.H. Yoon, K.b. Kim, Y.J. back, u.b. Korea Inst of Nuclear Safety Taejon South Korea

Most of the assessment equations for Ct which is a wellknown fracture parameter characterizing high temperature crack growth rates, have limited applicability to constant load conditions after sudden loading. However, crack growth due to creep can also occur under load varying conditions when load rising time is so long that accumulated creep deformation near the crack tip is not *** this paper, the estimation equation of the Ctparameter which can be applied to the case of slow load rising, i.e., (Ct)r, is explained. And the correlation between (Ct)r at the end of the load increasing period and Ct at the beginning of the succeeding load hold period is discussed. Finite element analyses of several cases with various loading conditions were performed and results were presented to show the effectiveness of the proposed Ct estimation scheme. The general applicability of the equation is also discussed.

关键词： creep fatigue crack time dependent fracture mechanics Ctparameter,C*integral

Directional solidification and physical properties measurements of the zinc-aluminum eutectic alloy

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International Journal of Minerals,Metallurgy and Materials 2011年第6期18卷 659-664页

作者： S.Engin u.byük H.Kaya N.Maraslι Department of Physics Institute of Science and TechnologyErciyes University Department of Science Education Faculty of EducationErciyes University Department of Physics Faculty of ScienceErciyes University

Zn-5wt% Al eutectic alloy was directionally solidified with different growth rates （5.32-250.0μm/s） at a constant temperature gradient of 8.50 K/mm using a bridgman-type growth *** values of eutectic spacing were measured from transverse sections of the *** dependences of the eutectic spacing and undercooling on growth rate are determined as λ=9.21V-0.53 and ΔT=0.0245V0.53,*** results obtained in this work were compared with the Jackson-Hunt eutectic theory and the similar experimental results in the *** of directionally solidified samples was also measured by using a microhardness test *** dependency of the microhardness on growth rate is found as Hv=***,the electrical resistivity （r） of the casting alloy changes from 40×10-9 to 108×10-9 Ω·m with the temperature rising in the range of 300-630 *** enthalpy of fusion （ΔH） and specific heat （Cp） for the Zn-Al eutectic alloy are calculated to be 113.37 J/g and 0.309 J/（g·K）,respectively by means of differential scanning calorimetry （DSC） from heating trace during the transformation from liquid to solid.

关键词： eutectic alloys directional solidification microhardness electrical conductivity enthalpy specific heat

Realization of laser textured brass surface via temperature tuning for surface wettability transition

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光电工程 2017年第6期44卷 587-592页

作者： Huangping Yan Mohamed Raiz b Ab.ul Rashid si Ying Khew Fengping Li Minghui Hong School of Aerospace Engineering Xiamen University Department of Electrical and Computer Engineering National University of Singapore School of Mechanical and Electrical Engineering Wenzhou University

Superhydrophobic surfaces have attracted extensive interests and researches into their fundamentals and potential *** texturing provides the convenience to fabricate the hierarchical micro/nanostructures for ***,after laser texturing,long wettability transition time from superhydrophilicity to superhydrophobicity is a barrier to mass production and practical industrial *** stimuli have been applied to change the surface composition and/or the surface morphology to reduce wettability transition ***,by temperature tuning,wettability transition of laser textured brass surfaces is *** electron microscopy and surface contact angle measurement are employed to characterize the surface morphology and wettability behavior of the textured brass *** low-temperature heating(100℃~150℃),partial deoxidation of the top Cu O layer occurs to form hydrophobic Cu_***,superhydrophobicity without any chemical coating and surface modification could be achieved in a short ***,after low-temperature heating,the low adhesive force between the water droplet and the sample surface is demonstrated for the laser textured brass *** study provides a simple method to fabricate the micro/nanostructure surfaces with controllable wettability for the potential applications.

关键词：纳米结构激光技术发展现状润湿性

EFFECTS OF DELAY AND SEASONALITY ON TOXIN PRODuCING PHYTOPLANKTON-ZOOPLANKTON SYSTEM

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International Journal of biomathematics 2012年第5期5卷 239-259页

作者： SuNITA GAKKHAR ANuRAJ siNGH bRAHAM pal siNGH Department of Mathematicsindian Institute of Technology Roorkee Roorkee 247667 Uttarakhand India Department of Mathematics J. V. Jain Degree CollegeSaharanpur 2~001 U.P. India

A dynamical model for toxin producing phytoplankton and zooplankton has been formu- lated and analyzed. Due to gestation of prey, a discrete time delay is incorporated in the predator dynamics. The stability of the delay model is discussed and Hopf bifurcation to a periodic orbit is established. Stability and direction of bifurcating periodic orbits are investigated using normal form theory and center manifold arguments. Global existence of periodic orbits is also established. To substantiate analytical findings, numerical simu- lations are performed. The system shows rich dynamic behavior including chaos and limit cycles. The influence of seasonality in intrinsic growth parameter of the phytoplankton population is also investigated. Seasonality leads to complexity in the system.

关键词： Time delay stability Hopf bifurcation period chaos.

biological Eagle-eye Inspired Target Detection for unmanned Aerial Vehicles Equipped with a Manipulator

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Machine Intelligence Research 2023年第5期20卷 741-752页

作者： Yi-Min Deng si-Yuan Wang School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Inspired by eagle eye mechanisms,the structure and information processing characteristics of the eagle′s visual system are used for the target capture task of an unmanned aerial vehicle(uAV)with a mechanical *** this paper,a novel eagle-eye inspired multi-camera sensor and a saliency detection method are proposed.A combined camera system is built by simulating the double fovea structure on the eagle retina.A saliency target detection method based on the eagle midbrain inhibition mechanism is proposed by measuring the static saliency information and dynamic ***,salient targets can be accurately detected through the collaborative work between different cameras of the proposed multi-camera *** results show that the eagle-eye inspired visual system is able to continuously detect targets in outdoor scenes and that the proposed algorithm has a strong inhibitory effect on moving background interference.

关键词： unmanned aerial vehicle(uAV) eagle eye multi-camera sensor target detection saliency detection