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Atomistic study of inverse size effect induced by interfacial plasticity in pearlitic multi-principal element alloy

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Rare Metals 2024年第7期43卷 3341-3355页

作者： Chen Yang Qiao-sheng xia Cun-Hong Yin Dong-Peng hua College of Mechanical Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Advanced manufacturing Technology Ministry of EducationGuizhou UniversityGuiyang 550025China State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi'an 710072China

Owing to the fine nano-laminated structure,the pearlitic multi-principal element alloy(PMPEA) exhibits excellent mechanical and tribological ***,the incomplete understanding of the size effect of its lamella thickness and the unclear understanding of the plasticity-interface interaction mechanism limit further optimization of *** this study,the FeCoNi/Ni_3Ti interface-mediated plastic deformation behavior in PMPEA and the variation of mechanical and tribological properties with lamella thickness within the nanoscale range using molecular dynamics(MD) simulation were *** results indicate that the mechanical and tribological properties of the PMPEA with lamella thicknesses below 10 nm have a significant inverse size effect,i.e.,the smaller the lamella thickness,the weaker the *** is because the plastic carrier-interface interaction mechanism changes from a strengthening mechanism that hinders dislocations to a weakening mechanism that promotes dislocations with the decreases in the lamella thickness,and the weakening effect becomes more pronounced as the lamella thickness decreases and the number of interfaces *** particular,the deformation behavior of Ni_3Ti lamellae changes from crystal-like to amorphous-like with decreasing ***,in the sample with larger lamella thickness,the occurrence of hierarchical slips in the body-centered cubic(BCC) phase due to the multiprincipal elements effect can better alleviate the stress concentration caused by the dislocation accumulation at the interface,so that the phase interface exhibits outstanding load-bearing *** the dislocation pattern in BCC phase shows a firm high-density cell,which makes the substrate exhibit a stable tribological response.

关键词： Multi-principal element alloy Nano-laminated structure Molecular dynamics simulation Nanoindentation and nanoscratch

Creep-Resistant Covalent Adaptable Networks with Excellent SelfHealing and Reprocessing Performance via Phase-Locked Dynamic Covalent Benzopyrazole-Urea Bonds

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Chinese Journal of Polymer Science 2024年第10期42卷 1545-1556,I0013页

作者： Miao Xie xiao-Rong Wang Zhan-hua Wang He-sheng xia State Key Laboratory of Polymer materials Engineering Polymer Research InstituteSichuan UniversityChengdu610065China School of Petrochemical Engineering Liaoning Petrochemical UniversityFushun113001China

Covalent adaptive networks(CANs)are capable of undergoing segment rearrangement after being heated,which endows the materials with excellent self-healing and reprocessing performance,providing an efficient solution to the environment pollution caused by the plastic *** main challenge remains in developing CANs with both excellent reprocessing performance and creep-resistance *** this study,a series of CANs containing dynamic covalent benzopyrazole-urea bonds were developed based on the addition reaction between benzopyrazole and isocyanate *** calculation confirmed that relatively low dissociation energy is obtained through undergoing a five-member ring transition state,confirming excellent dynamic property of the benzopyrazole-urea *** verified by the FTIR results,this nice dynamic property can be well maintained after incorporating the benzopyrazole-urea bonds into polymer *** self-healing and reprocessing performance is observed by the 3-ABP/PDMS elastomers owing to the dynamic benzopyrazole-urea *** separation induced by the aggregation of the hard segments locked the benzopyrazole-urea bonds,which also makes the elastomers display excellent creep-resistance *** hard phase locking strategy provides an efficient approach to design CANs materials with both excellent reprocessing and creep-resistance performance.

关键词： Covalent adaptive networks Self-healing polymer Dynamic covalent bond

Synthesis of graphitic carbon nitride through pyrolysis of melamine and its electrocatalysis for oxygen reduction reaction

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Chinese Chemical Letters 2013年第2期24卷 103-106页

作者： He-sheng Zhai Lei Cao Xing-hua xia Center for Scanning Electron Microscopy Xiamen University State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical Engineering.Nanjing University

Received 2 December 2012 Received in revised form 26 December 2012 Accepted 31 December 2012 Available online 4 February 2013

关键词： Melamineg-C3N4Oxygen reduction reactionElectrocatalysis

Evaluation of packet loss impairment on streaming video

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第Z1期7卷 131-136页

作者： RUI hua-xia LI Chong-rong QIU sheng-ke Network Research Center Tsinghua University Beijing 100084 China Network Research Center Tsinghua University Beijing 100084 China Network Research Center Tsinghua University Beijing 100084 China

Video compression technologies are essential in video streaming application because they could save a great amount of network resources. However compressed videos are also extremely sensitive to packet loss which is inevitable in today's best effort IP network. Therefore we think accurate evaluation of packet loss impairment on compressed video is very important. In this work, we develop an analytic model to describe these impairments without the reference of the original video (NR) and propose an impairment metric based on the model, which takes into account both impairment length and impairment strength. To evaluate an impaired frame or video, we design a detection and evaluation algorithm (DE algorithm) to compute the above metric value. The DE algorithm has low computational complexity and is currently being implemented in the real-time monitoring module of our HDTV over IP system. The impairment metric and DE algorithm could also be used in adaptive system or be used to compare diffeient error concealment strategies.

关键词： Packet loss, Video streaming, MPEg-2 video, Video quality, No-Reference

Curcumin-attenuated trinitrobenzene sulphonic acid induces chronic colitis by inhibiting expression of cyclooxygenase-2

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World Journal of gastroenterology 2006年第24期12卷 3848-3853页

作者： hua liang Chang-sheng Deng Ming Zhang jian xia Department of gastroenterology Zhongnan Hospital of WuhanUniversity Wuhan 430071 Hubei Province China

AIM： To explore the possible mechanisms of curcumin in rat colitis induced by trinitrobenzene sulfonic （TNBS） acid. METHODS： Rats with TNBS acid-induced colitis were treated with curcumin （30 mg/kg or 60 mg/kg per day ip）. Changes of body weight and histological scores as well as survival rate were evaluated. Leukocyte infiltration was detected by myeloperoxidase （MPO） activity assay. The expression of cyclooxygenase-2 （COX-2） was detected by RT-PCR and Western blot. Inflammation cytokines were determined by RT-PCR. Local concentration of prostaglandin E2 （PgE2） in colon mucosa was determined by ELISA. RESULTS： Curcumin improved survival rate and histological image, decreased the macroscopic scores and MPO activity. Also curcumin reduced the expression of COX-2 and inflammation cytokines. In addition, treatment with curcumin increased the PgE2 level. CONCLUSION： Curcumin has therapeutic effects on TNBS acid-induced colitis, the mechanisms seem to be related to COX-2 inhibition and PgE2 improvement.

关键词： Colitis Curcumin Cyclooxygenase-2 PgE2 TNBS acid

Multi-scale traffic vehicle detection based on faster ReCNN with NAS optimization and feature enrichment

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Defence Technology（防务技术） 2021年第4期17卷 1542-1554页

作者： Ji-qing Luo Hu-sheng Fang Fa-ming Shao Yue Zhong xia hua Department of Mechanical Engineering College of Field EngineeringArmy Engineering University of PLANanjing210007China

It well known that vehicle detection is an important component of the field of object ***,the environment of vehicle detection is particularly sophisticated in practical *** is comparatively difficult to detect vehicles of various scales in traffic scene images,because the vehicles partially obscured by green belts,roadblocks or other vehicles,as well as influence of some low illumination *** this paper,we present a model based on Faster ReCNN with NAS optimization and feature enrichment to realize the effective detection of multi-scale vehicle targets in traffic ***,we proposed a Retinex-based image adaptive correction algorithm(RIAC)to enhance the traffic images in the dataset to reduce the influence of shadow and illumination,and improve the image ***,in order to improve the feature expression of the backbone network,we conducted Neural Architecture Search(NAS)on the backbone network used for feature extraction of Faster ReCNN to generate the optimal cross-layer connection to extract multi-layer features more ***,we used the object Feature Enrichment that combines the multi-layer feature information and the context information of the last layer after cross-layer connection to enrich the information of vehicle targets,and improve the robustness of the model for challenging targets such as small scale and severe *** the implementation of the model,K-means clustering algorithm was used to select the suitable anchor size for our dataset to improve the convergence speed of the *** model has been trained and tested on the UN-DETRAC dataset,and the obtained results indicate that our method has art-of-state detection performance.

关键词： Neural architecture search Feature enrichment Faster R-CNN Retinex-based image adaptive correction algorithm K-means UN-DETRAC

Determination of a Reasonable Percentage for Ecological Water-Use in the Haihe River Basin, China

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Pedosphere 2006年第1期16卷 33-42页

作者： xia Jun FENg hua-Li ZHAN Che-sheng NIU Cun-Wen Key Laboratory of Water Cycle ＆ Related Land Surface Processes Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Science Beijing 100101 （China）. State Key Laboratory of Water Resources ＆ Hydropower Engineering Sciences Wuhan University Wuhan 430072（China） Nanjing Hydraulic Research Institute Nanjing 210029 （China）

An investigation was conducted to study problems of determining a reasonable percentage for ecological water-use in the Haihe River Basin of China. Three key aspects for the ecological water requirement （EWR） were analyzed, involving i） the EWR for river system, ii） the EWR for wetlands and lakes, and iii） the EWR for discharge into the sea to maintain the estuary ecological balance of the Haihe River. The Montana method and related water level-flow relationships, and the statistic approach based on hydrological records were applied to estimate different components of EWR. The results showed that the total ecological water demand in the region, was about 3.47-14.56 billion m^3. Considering flow regime change and uncertainty, the ecological water demand could be estimated by the hydrological frequency approach. Preliminary analysis showed that for different annual runoff under the frequencies of 20%, 50%, 75% and 95%, the ecological water demand approached 12%-50%, 18%-74%, 24%-103%, 35%-148% and 16%-66%, respectively. By further analysis to balance ecological water-use and socioeconomic water-use, the rational percentage of ecological water-use was estimated as 35%-74%, that provides useful information to judge whether the allocation of water resources is reasonable, and was proved to be satisfactory by comparing with the practical condition.

关键词： ecological water requirement ecological water-use Haihe River Basin

Occurrence of HTO and NE-OBT in soil in the vicinity of the Qinshan Nuclear Power Plant

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Nuclear Science and Techniques 2016年第4期27卷 1-6页

作者： lin du qin zhang zheng-hai xia yu-hua ma ling wang lai-lai qin ke deng sheng-wei wu guang-hua wang wei liu Shanghai Institute of Applied Physics Chinese Academy of Science Shanghai 201800 China University of Chinese Academy of Science Beijing 100049China CNNC Nuclear Power Operations management Co. Ltd Haiyan 314300 China Shanghai Tech University Shanghai 201210 China

In this study, concentrations of tritiated water(HTO) and non-exchangeable organically bound tritium(NE-OBT) and the NE-OBT/HTO ratios were determined in soil around Qinshan Nuclear Power Plant(NPP), Zhejiang, China, and their vertical profile and spatial distribution were investigated. Results showed variations in both the HTO and NE-OBT concentrations in the vertical profile. The HTO concentrations generally decreased firstly and then increased with the increasing depths, but the trend was not significant. The NE-OBT concentrations in the surface soils(0–5 cm) were considerably lower than those in the deep soils(5–25 cm) at all the sites. The NE-OBT/HTO ratios also show a variable vertical profile, initially increasing and then decreasing with increasing soil *** the HTO and NE-OBT concentrations decreased with the increasing distance to the HWRs in deep soil layers(5–25 cm), revealing that the released tritium from the NPP affected the spatial distribution.

关键词：土壤水秦山核电站空间分布土层深度秦山核电厂 HTO 水浓度氚浓度

Tumor necrosis factor receptor-associated protein 1 regulates hypoxia-induced apoptosis through a mitochondria-dependent pathway mediated by cytochrome c oxidase subunit Ⅱ

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Burns & Trauma 2019年第1期7卷 139-149页

作者： Fei xiang Si-yuan ma Yan-ling Lv Dong-xia Zhang hua-pei Song Yue-sheng hua.g Institute of Burn Research State Key Laboratory of TraumaBurns and Combined InjurySouthwest HospitalThird Military Medical University(Army Medical University)Chongqing 400038China

Background:Tumor necrosis factor receptor-associated protein 1(TRAP1)plays a protective effect in hypoxic cardiomyocytes,but the precise mechanisms are not well *** study is aimed to identify the mechanism of TRAP1 on hypoxic damage in ***:In this study,the effects of TRAP1 and cytochrome c oxidase subunit Ⅱ(COXⅡ)on apoptosis in hypoxia-induced cardiomyocytes were explored using overexpression and knockdown methods ***:Hypoxia induced cardiomyocyte apoptosis,and TRAP1 overexpression notably inhibited apoptosis induced by ***,TRAP1 silencing promoted apoptosis in hypoxic *** investigation revealed that the proapoptotic effects caused by the silencing of TRAP1 were prevented by COXⅡ overexpression,whereas COXⅡ knockdown reduced the antiapoptotic function induced by TRAP1 ***,changes in the release of cytochrome c from mitochondria into the cytosol and the caspase-3 activity in the cytoplasm,as well as reactive oxygen species production,were found to be correlated with the changes in ***:The current study uncovered that TRAP1 regulates hypoxia-induced cardiomyocyte apoptosis through a mitochondria-dependent apoptotic pathway mediated by COXⅡ,in which reactive oxygen species presents as an important component.

关键词： Cardiomyocytes Hypoxia Tumor necrosis factor receptor-associated protein 1 Cytochrome c oxidase subunitⅡ Reactive oxygen species Apoptosis