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Enhancement of thermal stability and high-temperature oxidation resistance of chromium oxide-based films by addition of rare earth element Y

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Journal of Materials Science & Technology 2024年第21期188卷 105-115页

作者： Bingsen jia Wenju Xu jingfeng li Xiaohong liu li ji Chufeng Sun jia li Hongxuan li State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China School of Chemical Engineering Northwest Minzu UniversityLanzhou 730030China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Chromium oxide ceramic materials are widely used in high-temperature applications requiring high wear resistance and *** further improve the friction and wear performance and high-temperature stability of chromium oxide thin films,this study attempted to dope rare earth(RE)element Y(yttrium)and deposited CrYO high-temperature self-lubricating ceramic thin films with different doping levels on the surface of IN718 alloys by using multi-arc ion plating *** deposited films were annealed at 1000℃for 2 h under atmospheric conditions to analyze the changes in phase composition and thickness,and the friction and wear characteristics of the CrYO films were tested using a high-temperature friction and wear tester in the temperature range of 25–600℃.The results show that the CrYO-2 film has a dense multilayer structure,and the multilayer oxide film produces interlayer sliding under frictional shear,thus providing *** particular,the friction coefficients are as low as about 0.25 in the middle and high-temperature sections(400,600℃),which provides good high-temperature tribological *** addition,the doping of Y elements dramatically affects the formation of the oxide layer and the distribution of voids in the film,changing the diffusion process of the elements of the base material inside the film and at the film-air interface at high *** two annealing treatments,the film thickness increased from 1.81 to 2.25μm,and the volume expansion of the films was effectively controlled compared with that of the Cr_(2)O_(3)films.

关键词： CrYO film Multilayer structure High-temperature lubrication Thermal stability

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Texture-based magnetostriction calculation of oriented polycrystalline cobalt ferrites

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Rare Metals 2018年第5期37卷 421-426页

作者： ji-Quan Wang ji-Heng li Chao Yuan Xiao-Qian Bao Xue-Xu Gao State Key Laboratory of Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083China

Oriented polycrystalline cobalt ferrites with different alignments were prepared via a ceramic method. The maximum magnetostriction λs up to -270×10^-6 was achieved for oriented samples, when the oriented magnetic field was above 1.0 T. Textures of all samples were determined by electron back-scattered diffraction （EBSD） technique and were used to calculate magnetostriction values of oriented polycrystalline cobalt ferrite samples. Results show that a preferred 〈001〉 orientation has been obtained within oriented sample. Calculation was done by considering the magnetostriction value as the sum of the content in volume fraction-weighted single-crystal behavior along [100], [110], [210], [310], [311], [211] and [111] directions. The calculated magnetostriction values when compared with experimentally obtained values show identical behavior as a function of applied magnetization orientation field. Good consistency of change rules between calculated values and measured ones illustrates the successful application of this method in predicting magnetostriction values of polycrystalline materials.

关键词： Magnetostriction calculation Oriented polycrystalline Cobalt ferrites Texture

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Preliminary Study on lipase-catalyzed Synthesis of Polyesters Containing L-Malic Acid Units

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Chinese Chemical Letters 2006年第12期17卷 1611-1614页

作者： Da Hu YAO Guang ji li College of Materials Science and Engineer South China University of Technology Guangzhou 510640

Terpolymer of 1, 8-octanediol, adipic acid, and L-malic acid was synthesized via a lipase-catalyzed direct polycondensation. The products were characterized by GPC and 1H NMR. The results indicated that the molecular weight of the prepared polymers decreased with increasing L-malic acid content in the monomer feed ratio, and that change in the L-malic acid content from 0 to 20 mol % did not remarkably influenced on the molecular weight distribution Mw /Ma of the prepared samples. The 1H NMR spectra of the obtained copolymer samples showed that hydroxyl groups of L-malic acid did not take part in the polymerization reaction.

关键词： L-Malic acid polycondensation lipase polyester.

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The influence of water level changes on sand bodies at river-dominated delta fronts:The Gubei Sag,Bohai Bay Basin

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Petroleum Science 2022年第1期19卷 58-73页

作者： Yang Zhang Zheng Shi ji li Jun-Wei Wang Bao-liang Yang ji-Guo jiang Faculty of Petroleum China University of Petroleum(Beijing)Karamay CampusKaramayXinjiang834000China College of Resources and Environmental Engineering Guizhou Institute of TechnologyGuiyangGuizhou550003China Experiment Testing Institute PetroChina Xinjiang Oilfield CompanyKaramayXinjiang834000China Research Institute of Exploration and Development PetroChina Xinjiang Oilfield CompanyKaramayXinjiang834000China School of Geosciences China University of PetroleumQingdaoShandong266580China Zhuangxi Oil Production Plant Sinopec Shengli Oilfield CompanyDongyingShandong257000China

Changes in water level are one of the important factors controlling the constructive characteristics of *** paper studies the influence of water level changes on sand bodies in the third member of the Shahejie Formation(Es3)on the gentle southern slope of the Gubei Sag,Bohai Bay Basin and draw some conclusions that,for complex sand bodies,with the increase in water level the distributary channels bifurcate frequently,from a simple branching shape to a network shape along with the increase in the development of crevasse splays,mouth bars and sheet *** single sand bodies,with an increase in water level in the slope zone of the lake basin close to the source area,the superimposition style transitioned from vertical cutting-stacking and lateral isolation to vertical stitching,isolation and lateral ***,in the central zone of the lake basin far from the source area,the superimposition style transitioned from vertical stitching and lateral stitching to vertical isolation and lateral *** water level stays stable,the greater the distance from the source area the greater the disaggregation ratio of a single sand *** the same distance from the source area,higher water level tends to result in greater disaggregation ratio of a single sand body.

关键词： Water level changes River-dominated delta Delta front sandbodies Paleogene Shahejie Formation Gubei Sag of Bohai Bay Basin

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Correlation between mechanical and thermodynamic properties for La-Ce-Ni-Cu-Al high-entropy metallic glasses

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Journal of Iron and Steel Research International 2018年第6期25卷 658-665页

作者： lin Wu Yong Zhao Jun-jun li ji-li Wu Bo Zhang Institute of Amorphous Matter Science and School ofMaterials Science and Engineering Hefei University of Technology Hefei 230009 Anhui China

The mechanical properties, thermodynamic features and their correlation were studied for La-Ce-Ni-Cu-Al high-entropy bulk metallic glasses （HE-BMGs）. Compressive testing indicated that the HE-BMGs are ductile on a microscopic scale but brittle on a macroscopic scale, because of the low fragility index rn of the HE-BMGs. In the non-isothermal process, the activation energies for glass transition for these HE-BMGs are the lowest of the known HE-BMGs. Large values of the Avrami exponent n imply that the crystallization process proceeded through three-dimensional growth and with an increasing nucleation rate. The activation energy for glass transition （Eg） is almost proportional to the HE-BMG fracture strength, because a higher Eg is required to dislodge the molecules from the glassy configuration for the HE-BMGs with a high strength. The findings provide unambiguous evidence for the correlation between the mechanical and thermodynamic properties.

关键词： High-entropy bulk metallic glass Fracture mechanism Crystallization Avrami exponent Glass-transitionactivation energy

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Cross-layer scheduling with fairness for multi-user OFDM system:a restless bandit approach

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The Journal of China Universities of Posts and Telecommunications 2011年第4期18卷 25-30页

作者： GE Wen-dong ji Hong li Xi Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

In OFDM-based System such as long term evolution （LTE）, the scheduling scheme plays an essential role in not only improving the capacity of system, but also guarantee the fairness among the user equipments （UEs）. However, most existing work about scheduling only considers the current throughput in physical layer. Thus in this paper, a cross-layer scheduling with fairness based on restless bandit （CSFRB） scheme with the ＇indexability＇ property is proposed for the multi-user orthogonal frequency-division multiplexing （OFDM） system to minimize the distortion in the application layer, to maximize the throughput and to minimize the energy consumption in the physical layer. The scheduling problem is firstly established as a restless bandit problem, which is solved by the primal-dual index heuristic algorithm based on the first order relaxation with low complexity, to yield the CSFRB scheme. AdditionaUy, this scheme is divided into offiine computation and online selection, where main work will be finished in former one so as to decrease the complexity further. Finally, extensive simulation results illustrate the significant performance improvement of the proposed CSFRB scheme compared to the existing one in different scenarios.

关键词： multi-user OFDM scheduling cross-layer design restless bandits

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Single gate optimization for plastic injection mold

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第7期8卷 1077-1083页

作者： li ji-quan li De-qun GUO Zhi-ying LV Hai-yuan Department of Plasticity Technology Shanghai Jiao Tong University Shanghai 200030 China

This paper deals with a methodology for single gate location optimization for plastic injection mold. The objective of the gate optimization is to minimize the warpage of injection molded parts, because warpage is a crucial quality issue for most injection molded parts while it is influenced greatly by the gate location. Feature warpage is defined as the ratio of maximum displacement on the feature surface to the projected length of the feature surface to describe part warpage. The optimization is combined with the numerical simulation technology to find the optimal gate location, in which the simulated annealing algorithm is used to search for the optimum. Finally, an example is discussed in the paper and it can be concluded that the proposed method is effective.

关键词： Injection mold Gate location Optimization Feature warpage

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Load-adaptive frequency reuse scheme for inter-cell interference coordination in relay networks

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The Journal of China Universities of Posts and Telecommunications 2010年第5期17卷 38-43页

作者： CHEN Mu-qiong ji Hong li Xi School of Information and Telecommunication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

Cellular relay networks adopting orthogonal frequency division multiple （OFDM） technology has been widely accepted for next generation wireless communication due to its advantage in enlarging coverage scale as well as improving data *** order to improve the performance of user equipments （UEs） near the cell edge,especially to avoid the interference from inter-cell and intra cell,an enhanced soft frequency reuse scheme is adopted in this paper to assure inter-cell interference coordination （ICIC）.Compared with traditional frequency allocation work,the proposed scheme is interference-aware and load-adaptive,which dynamically assigns available frequency among UEs under certain schedule method in variable traffic load condition and mitigates interference using information provided by interference *** can improve signal-to-interference plus noise ratio （SINR） of the UE in each sub channel thus enable the system achieve better throughput and blocking probability *** results prove that the proposed scheme may achieve desirable performance on throughput,blocking probability and spectral utilization in the sector under different traffic load compared with other schemes.

关键词： relay frequency reuse interference coordination resource allocation

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Chemical additives affect sulfate reducing bacteria biofilm properties adsorbed on stainless steel 316L surface in circulating cooling water system

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Frontiers of Environmental Science & Engineering 2017年第2期11卷 143-156页

作者： Yu Qi jin li Rui liang Sitong ji jianxiang li Meng liu Research Center for Aqueous Organic Pollutants Control and Water Quality Security Beijing Key Laboratory Beijing Jiaotong University Beijing 100044 China

This paper studied the biofilm properties and corrosion behavior of sulfate reducing bacteria （SRB） on stainless steel 316L （SS316L） surface in circulating cooling water system with and without additives including hydroxy ethyl fork phosphonic acid （HEDP）, dodecyl dimethyl benzyl anunonium chlotide （1227） and NaClO. Biochemical technique, electrochemical technology, X-ray photoelectron spectroscopy （XPS） and scanning electron microscope （SEM） were used. The results show that the extracellular polymeric substance （EPS） in biofilm attached on the SS316L surface mainly contain proteins and polysaccharides, the contents are 98 ***-2 and ***-2, respectively. The polysaccharides were cut by 1227 about 80%, while 55% by NaCIO. The proteins were reduced by NaCIO about 53%, while only 30% by 1227. The potentiodynamic polarization shows that the corrosion potential of SS316L was enhanced from -0.495 V to -0.390 V by the chemical additive delaying the occurrence of the corrosion. And the corrosion rate was also reduced from 5.19 × 10^-3 mm·a^-1 to 2.42 × 10^-3 mm＇a . But NaCIO stdl caused pitting corrosion after stenhzmg the bacteria, while 1227 can form a protective film on the surface of SS316L. Though HEDP contribute to the bacteria activity, it can enhance the breakdown potential. XPS results confirmed that 1227 can change the value of C：O in the biofilm attached on metal surface, and NaCIO can eliminate the existence of amidogen. This study would provide some recommendations for the selection of chemical additives in the thermal power plant.

关键词： Sulfate reducing bacteria (SRB)Chemical additivesBiofilmExtracellular polymeric substance (EPS)Microbe conosion

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Recent progress in layered rare-earth hydroxide (LRH) and its application in luminescence

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Journal of Advanced Ceramics 2017年第3期6卷 177-186页

作者： Qi ZHU Xuejiao WANG ji-Guang li Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education) Northeastern University Shenyang 110819 ChinaInstitute of Ceramics and Powder Metallurgy School of Materials Science and Engineering Northeastern University Shenyang 110819 China Research Center for Functional Materials National Institute for Materials Science Namiki 1-1 Tsukuba Ibaraki 305-0044 JapanCollege of New Energy Bohai University Jinzhou 121000 China Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education) Northeastern University Shenyang 110819 ChinaInstitute of Ceramics and Powder Metallurgy School of Materials Science and Engineering Northeastern University Shenyang 110819 ChinaResearch Center for Functional Materials National Institute for Materials Science Namiki 1-1 Tsukuba Ibaraki 305-0044 Japan

This review article compiles the recent achievements made in layered rare-earth (RE) hydroxide (LRH), including controlled crystallization, structural and morphological features, anion exchange, nanosheet exfoliation, and application in the field of luminescence for both the Ln2(OH)5(Ax-)1/x·nH2O (251-LRH) and Ln2(OH)4(Ax-)2/x·nH2O (241-LRH) phases. The luminescent properties of the LRHs themselves, the oxide, oxysulfate, and oxysulfide phosphors derived from the LRHs via controlled calcination, and the highly oriented transparent phosphor films of enhanced luminescence and/or novel emission features are summarized.

关键词： layered rare-earth hydroxide (LRH) anion exchange exfoliation assembly luminescence

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