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Effect of tungsten carbide particles on microstructure and mechanical properties of Cu alloy composite bit matrix

Journal of Iron and Steel Research International 2024年第2期31卷 519-530页

作者： Ding-qian Dong Feng-yuan He Xin-hui Chen Hui Li Kai-hua Shi Hui-wen Xiong Xin Xiang Li Zhang college of Mechanical Engineering Sichuan University of Science and EngineeringZigong643000SichuanChina State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083HunanChina Zigong Cemented Carbide Co. Ltd.Zigong643011SichuanChina Material Corrosion and Protection Key Laboratory of sichuan Province Sichuan University of Science and EngineeringZigong643000SichuanChina

Copper alloy composite bit matrix was prepared by pressureless vacuum infiltration,using at least one of the three kinds of tungsten carbide particles,for example,irregular cast tungsten carbide,monocrystalline tungsten carbide and sintered reduced tungsten carbide *** effects of powder particle morphology,particle size and mass fraction of tungsten carbide on the microstructure and mechanical properties of copper alloy composite were investigated by means of scanning electron microscopy,X-ray diffraction and abrasive wear test in *** results show that tungsten carbide morphology and particle size have obvious effects on the mechanical properties of copper alloy *** tungsten carbide partially dissolved in the copper alloy binding phase,and layers of Cu_(0.3)W_(0.5)Ni_(0.1)Mn_(0.1)C phase with a thickness of around 8–15μm were formed on the edge of the cast tungsten *** 45%irregular crushed fine cast tungsten carbide and 15%monocrystalline cast tungsten carbide were used as the skeleton,satisfactory comprehensive performance of the reinforced copper alloy composite bit matrix was obtained,with the bending strength,impact toughness and hardness reaching 1048 MPa,4.95 J/cm^(2) and 43.6 HRC,*** main wear mechanism was that the tungsten carbide particles firstly protruded from the friction surface after the copper alloy matrix was worn,and then peeled off from the matrix when further wear occurred.

关键词： Polycrystalline diamond compact Pressureless vacuum infiltration Copper alloy composite bit matrix Microstructure characterization Abrasive wear behavior

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Double-stranded DNA-nucleic acid dye complex-sensitized biocatalytic photosynthesis:Base pairing-switched regeneration of nicotinamide cofactor

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Journal of Energy Chemistry 2024年第7期94卷 618-624页

作者： Zhen Dong Yanying Wang Dan Li Peng Wu college of Chemistry Sichuan UniversityChengdu 610064SichuanChina Analytical&Testing Centre State Key Laboratory of Hydraulics and Mountain River EngineeringSichuan UniversityChengdu 610064SichuanChina School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang 453007HenanChina

Photo-biocatalysis,the combination of photosensitization and biocatalysis,is an emerging solution for sunlight-based renewable *** is thus important to develop light antennas with both good light har-vesting and efficient electron ***,the intriguing electrical conductivity of dsDNA and its host effect(for nucleic acid dyes to harvest light)were explored simultaneously to develop a dsDNA-based light antenna for *** SYBR Green I(SG)as the example of the nucleic acid dye,the proposed SG-dsDNA system was found to be capable for visible-light-driven reduced nicotinamide adenine dinucleotide(NADH)regeneration,and the turnover frequency of which(1.35 min^(-1))exceeded most of the existing photocatalytic *** SG can only be hosted by dsDNA,meanwhile dsDNA can be formed through hybridization between single strand DNA and its complementary strand,the pro-posed system adds an extra control of the photocatalytic activity(DNA base pairing-based switch).When integrating the SG-dsDNA system with NADH-dependent horse liver alcohol dehydrogenase(HLADH),successful synthesis of 2-phenylpropanol(a crucial intermediates of profens manufacturing)was achieved.

关键词： Photosynthesis dsDNA SYBRGreenI TICT 2-phenylpropanol

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Enhanced Ion-Selective Diffusion Achieved by Supramolecular Interaction for High Thermovoltage and Thermal Stability

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Energy & Environmental Materials 2024年第2期7卷 204-212页

作者： Jiale Ke Xing Zhao Jie Yang Kai Ke Yu Wang Mingbo Yang Wei Yang college of Polymer Science and Engineering Sichuan University State Key Laboratory of Polymer Materials Engineering

Thermoelectric（TE） generators capable of converting thermal energy into applicable electricity have gained great popularity among emerging energy conversion ***-based ionic thermoelectric（i-TE）materials are promising candidates for energy conversion systems because of their wide sources,innocuity,and low manufacturing ***,common physically crosslinked biopolymer gels induced by single hydrogen bonding or hydrophobic interaction suffer from low differential thermal voltage and poor thermodynamic ***,we develop a novel i-TE gel with supramolecular structures through multiple noncovalent interactions between ionic liquids（ILs） and gelatin molecular *** thermopower and thermoelectric power factor of the ionic gels are as high as 2.83 mV K-1and 18.33 μW m-1K-2,*** quasi-solid-state gelatin-[EMIM]DCA i-TE cells achieve ultrahigh 2 h output energy density(E2h=9.9 mJ m-2) under an optimal temperature ***,the remarkable stability of the supramolecular structure provides the i-TE hydrogels with a thermal stability of up to 80 ℃.It breaks the limitation that biopolymer-based i-TE gels can only be applied in the low temperature range and enables biopolymer-based i-TE materials to pursue better performance in a higher temperature range.

关键词： biopolymer gel ionic liquid multiple noncovalent interactions supramolecular structure thermoelectric conversion

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Effect of dynamic loading orientation on fracture properties of surrounding rocks in twin tunnels

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 393-409页

作者： Ze Deng Zheming Zhu Lei Zhou Leijun Ma Jianwei Huang Yao Zhang Key Laboratory of Deep Earth and Engineering(Ministry of Education) College of Architecture and EnvironmentSichuan UniversityChengdu610065China Failure Mechanics and Engineering Disaster Prevention Key Laboratory of sichuan Province College of Architecture and EnvironmentSichuan UniversityChengdu610065China Institute for Disaster Management and Reconstruction Sichuan UniversityChengdu610065China

For expedited transportation,vehicular tunnels are often designed as two adjacent tunnels,which frequently experience dynamic stress waves from various orientations during blasting *** analyze the impact of dynamic loading orientation on the stability of the twin-tunnel,a split Hopkinson pressure bar(SHPB)apparatus was used to conduct a dynamic test on the twin-tunnel *** two tunnels were rotated around the specimen’s center to consider the effect of dynamic loading ***-DYNA software was used for numerical simulation to reveal the failure properties and stress wave propagation law of the twin-tunnel *** findings indicate that,for a twin-tunnel exposed to a dynamic load from different orientations,the crack initiation position appears most often at the tunnel corner,tunnel spandrel,and tunnel *** the impact direction is created by a certain angle(30°,45°,60°,120°,135°,and 150°),the fractures are produced in the middle of the line between the left tunnel corner and the right tunnel *** the impact loading angle(a)is 90°,the tunnel sustains minimal damage,and only tensile fractures form in the surrounding *** orientation of the impact load could change the stress distribution in the twin-tunnel,and major fractures are more likely to form in areas where the tensile stress is concentrated.

关键词： Twin-tunnel Dynamic load Split Hopkinson pressure bar(SHPB) Fracture mode Stress distribution Displacement field distribution

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A HEVC Video Steganalysis Method Using the Optimality of Motion Vector Prediction

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Computers, Materials & Continua 2024年第5期79卷 2085-2103页

作者： Jun Li Minqing Zhang Ke Niu Yingnan Zhang Xiaoyuan Yang college of Cryptography Engineering Engineering University of the Chinese People’s Armed Police ForceXi’an710086China Key Laboratory of Network and Information Security of the Chinese People’s Armed police Force Xi’an710086China

Among steganalysis techniques,detection against MV(motion vector)domain-based video steganography in the HEVC(High Efficiency Video Coding)standard remains a challenging *** the purpose of improving the detection performance,this paper proposes a steganalysis method that can perfectly detectMV-based steganography in ***,we define the local optimality of MVP(Motion Vector Prediction)based on the technology of AMVP(Advanced Motion Vector Prediction).Secondly,we analyze that in HEVC video,message embedding either usingMVP index orMVD(Motion Vector Difference)may destroy the above optimality of *** then,we define the optimal rate of MVP as a steganalysis ***,we conduct steganalysis detection experiments on two general datasets for three popular steganographymethods and compare the performance with four state-ofthe-art steganalysis *** experimental results demonstrate the effectiveness of the proposed feature ***,our method stands out for its practical applicability,requiring no model training and exhibiting low computational complexity,making it a viable solution for real-world scenarios.

关键词： Video steganography video steganalysis motion vector prediction motion vector difference advanced motion vector prediction local optimality

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Selenomethionine alleviates chronic heat stress-induced breast muscle injury and poor meat quality in broilers via relieving mitochondrial dysfunction and endoplasmic reticulum stress

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Animal Nutrition 2024年第1期16卷 363-375页

作者： Jinzhong Jing Jiayi Wang Xiaoyu Xiang Shenggang Yin Jiayong Tang Longqiong Wang Gang Jia Guangmang Liu Xiaoling Chen Gang Tian Jingyi Cai Bo Kang Lianqiang Che Hua Zhao Key Laboratory for Animal Disease-Resistance Nutrition of Ministry of Education of China Ministry of Agriculture and Rural Affairs of Sichuan Province Animal Nutrition Institute Sichuan Agricultural University Chengdu 611130 Sichuan China college of Animal Science and Technology Sichuan Agricultural University Chengdu 611130 Sichuan China

In the present study, the chronic heat stress (CHS) broiler model was developed to investigate the potential protection mechanism of organic selenium (selenomethionine, SeMet) on CHS-induced skeletal muscle growth retardation and poor meat quality. Four hundred Arbor Acres male broilers (680 ± 70 g, 21 d old) were grouped into 5 treatments with 8 replicates of 10 broilers per replicate. Broilers in the control group were raised in a thermoneutral environment (22 ± 2 °C) and fed with a basal diet. The other four treatments were exposed to hyperthermic conditions (33 ± 2 °C, 24 h in each day) and fed on the basal diet supplied with SeMet at 0.0, 0.2, 0.4, and 0.6 mg Se/kg, respectively, for 21 d. Results showed that CHS reduced ( P < 0.05) the growth performance, decreased ( P < 0.05) the breast muscle weight and impaired the meat quality of breast muscle in broilers. CHS induced protein metabolic disorder in breast muscle, which increased ( P < 0.05) the expression of caspase 3, caspase 8, caspase 9 and ubiquitin proteasome system related genes, while decreased the protein expression of P-4EBP1. CHS also decreased the antioxidant capacity and induced mitochondrial stress and endoplasmic reticulum (ER) stress in breast muscle, which increased ( P < 0.05) the ROS levels, decreased the concentration of ATP, increased the protein expression of HSP60 and CLPX, and increased ( P < 0.05) the expression of ER stress biomarkers. Dietary SeMet supplementation linearly increased ( P < 0.05) breast muscle Se concentration and exhibited protective effects via up-regulating the expression of the selenotranscriptome and several key selenoproteins, which increased ( P < 0.05) body weight, improved meat quality, enhanced antioxidant capacity and mitigated mitochondrial stress and ER stress. What's more, SeMet suppressed protein degradation and improved protein biosynthesis though inhibiting the caspase and ubiquitin proteasome system and promoting the mTOR-4EBP1 pathway. In co

关键词： Broiler Chronic heat stress Skeletal muscle Meat quality Mitochondrial dysfunction Endoplasmic reticulum stress

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Greedy Lattice Paths with General Weights

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Acta Mathematica Sinica,English Series 2024年第9期40卷 2213-2222页

作者： Yin Shan CHANG An Qi ZHENG college of Mathematics Sichuan UniversityChengdu 610065P.R.China

Let{X_(v):v∈Z^(d)}be *** *** S(π)=Σ_(v∈π)X_(v)be the weight of a self-avoiding lattice pathπ.Let M_(n)=max{S(π):πhas length n and starts from the origin}.We are interested in the asymptotics of Mn as n→∞.This model is closely related to the first passage percolation when the weights{X_(v):v∈Z^(d)}are non-positive and it is closely related to the last passage percolation when the weights{X_(v):v∈Z^(d)}are *** general weights,this model could be viewed as an interpolation between first passage models and last passage ***,this model is also closely related to a variant of the position of right-most particles of branching random *** the two assumptions that∃α>0,E(X_(0)^(+))^(d)(log^(+)X_(0)^(+))^(d+α)0,E(X_(0)^(+))^(d)(log^(+)X_(0)^(+))^(d+α)<+∞and that E[(X_(0)^(−))^(4)]<+∞,we prove that M_(n)/n converges to the same constant M almost surely as n tends to infinity.

关键词： Last passage percolation first passage percolation greedy lattice path

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Dual carbon goal and agriculture in China:Exploring key factors influencing farmers’behavior in adopting low carbon technologies

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Journal of Integrative Agriculture 2024年第9期23卷 3215-3233页

作者： Jinpeng Zou Lulin Shen Fang Wang Hong Tang Ziyang Zhou college of Management Sichuan Agricultural UniversityChengdu 611130China

Identifying the factors influencing farmers’adoption of low-carbon technologies(FA)and understanding their impacts are essential for shaping effective agricultural policies amied at emission reduction and carbon sequestration in *** study employs a meta-analysis of 122 empirical studies,delves into 23 driving factors affecting FA and addresses the inconsistencies present in the existing *** systematically examine the effect size,source of heterogeneity,and time-accumulation effect of the driving factors on *** find that significant heterogeneity in the factors influencing FA,except for farming experience,sources of heterogeneity from the survey zone,methodology model,technological attributes,report source,financial support,and the sampling ***,age,farming experience,and adoption cost negatively correlate with *** contrast,educational level,health status,technical training,economic and welfare cognition,land contract,soil quality,terrain,information accessibility,demonstration,government promotion,government regulation,government support,agricultural cooperatives member,peer effect,and agricultural income ratio demonstrate a positive ***,demonstration and age show a particularly strong ***,the effect of demonstration,age,economic and welfare cognition,farming experience,land contract,soil quality,information accessibility,government promotion,and support,as well as agricultural cooperative membership and peer effects on FA,are generally stable but exhibit varying degrees of attenuation over *** effect of village cadre,family income,farm scale,gender,health status,technical training,and off-farm work on FA show notable temporal shifts and maintain a weak correlation with *** study contributes to shaping China’s current low-carbon agriculture policies across various *** encourages policymakers to comprehensively consider the stability of key factors,other potential factors,technologic

关键词： farmers influencing factors low-carbon technology adoption meta-analysis

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Distinguishing the observational signatures of hot spots orbiting Reissner-Nordström spacetime

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Chinese Physics C 2024年第7期48卷 221-230页

作者：吴天枢陈一千 Center for Theoretical Physics College of PhysicsSichuan UniversityChengdu 610064China

This paper investigates observable signatures of hot spots orbiting Reissner-Nordström(RN)black holes and naked *** an RN black hole,we find two discernible lensing image tracks in time integrated images,capturing a complete orbit of hot spots and a image shadow within the critical curve where photons with a small impact parameter fall into the event ***,in RN singularities,additional image tracks can be found within the critical curve,originating from photons reflected by the infinitely high effective potential ***,we find incomplete and converging tracks from the time integrated images of hot spot orbiting RN singularities that have no photon *** presence of these additional image tracks significantly influences temporal magnitudes at their local maxima,enabling us to differentiate between RN black holes and RN naked singularities.

关键词： astrometry gravitational lensing black hole physics D0I:10.1088/1674-1137/ad3c2d

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A strategy for mechanically integrating robust hydrogeltissue hybrid to promote the anti-calcification and endothelialization of bioprosthetic heart valve

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Regenerative Biomaterials 2024年第2期3卷 123-136页

作者： Haoshuang Wu Nuoya Chen Tiantian Zheng Li Li Mengyue Hu Yumei Qin Gaoyang Guo Li Yang Yunbing Wang National Engineering Research Center for Biomaterials Sichuan UniversityChengdu 610065China Institute of Clinical Pathology West China Hospital of Sichuan UniversityChengdu 610041China college of Polymer Science and Engineering Sichuan UniversityChengdu 610065China

Bioprosthetic heart valve(BHV)replacement has been the predo-minant treatment for severe heart valve diseases over *** clinically available BHVs are crosslinked by glutaraldehyde(GLUT),while the high toxicity of residual GLUT could initiate calcification,severe thrombosis,and delayed ***,we construed a mechanically integrating robust hydrogel-tissue hybrid to improve the performance of *** particular,recombinant humanized coilagen type Ⅲ(rhCOLⅢ),which was precisely customized with anti-coagulant and pro-endothelialization bioactivity,was first incorporated into the polyvinyl alcohol(PVA)-based hydrogel via hydrogen bond ***,tannic acid was introduced to enhance the mechanicalperfo of PVA-based hvdrogel and interfacial bonding between the hydrogel layer and bio-derived tissue due to the strong affinity for a wide range of *** vitro and in vivo experimental results confirmed that the GLUT-crosslinked BHVs modified by the robust PVA-based hydrogel embedded rhCOLII and TA possessed long-term anti-coagulant,accelerated endothelialization,mild inflammatory response and anti-calcification ***,our mechanically integrating robust hydrogel-tissue hybrid strategy showed the potential to enhance the service function and prolong the service life of the BHVs after implantation.

关键词： bioprosthetic heart valves recombinant humanized collagen typeⅢ endothelialization anti-calcification anti-coagulation

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