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Oxidation behavior of multi-component Ta-W-Al-Ti alloy at 1173 K

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Rare Metals 2021年第7期40卷 1940-1948页

作者： Jia-Xin Li yu-Hong Chen Zhang-Jun bai Bao-Jun Zhao Liang Jiang Lan-er Wu School of Materials Science and engineering North Minzu UniversityYinchuan 750021China CNMC Ningxia Orient Group Co.Ltd Shizuishan 753000China School of Chemical engineering The University of QueenslandBrisbaneQLD 4072Australia

Ta-W alloys have unique properties but their applications at high temperatures are restricted due to their poor oxidation *** addition of Al and Ti decreases the oxidation rate of the alloy,as Al-contained protective oxide layer could be *** this study,ternary and quaternary Ta-W alloys containing Al and Ti were prepared by hot press *** microstructures and oxidation behaviors of the alloys were studied at1173 *** results show that the oxidation kinetics of all alloys follows a parabolic law at short oxidation *** cyclic oxidation,the kinetics of quaternary alloys still obeys the parabolic law but that of ternary alloy has been changed into linear law kinetics after 8-h *** ternary alloy,an outer layer with dense and continuous alumina was formed during the initial stage,and phase transformation caused the oxides to peel *** comparison,the quaternary alloys depicted continuously solid solution of the oxides ***,Al and Ti played key roles in oxidation degree and affected the oxidation kinetics of ternary and quaternary alloys.

关键词： Oxidation behavior Ta-W-based alloy Aluminum Titanium

Variable selection in identification of a high dimensional nonlinear non-parametric system

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Control Theory and Technology 2015年第1期13卷 1-16页

作者： er-Wei bai Wenxiao ZhaO Weixing ZHeNG Department of electrical and Computer engineering University of Iowa School of electronics Electrical Engineering and Computer Science Queen's UniversityBelfast U.K. Key Laboratory of Systems and Control Academy of Mathematics and Systems Science National Center for Mathematics and Interdisciplinary Sciences Chinese Academy of Sciences School of Computing Engineering and Mathematics University of Western Sydney

The problem of variable selection in system identification of a high dimensional nonlinear non-parametric system is described. The inherent difficulty, the curse of dimensionality, is introduced. Then its connections to various topics and research areas are briefly discussed, including order determination, pattern recognition, data mining, machine learning, statistical regression and manifold embedding. Finally, some results of variable selection in system identification in the recent literature are presented.

关键词： System identification variable selection nonlinear non-parametric system curse of dimensionality

Prospects of the Multi-channel Photometric Survey Telescope in the Cosmological Application of Type Ia Supernovae

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Research in Astronomy and Astrophysics 2024年第4期24卷 183-191页

作者： Zhenyu Wang Jujia Zhang Xinzhong er Jinming bai yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory for the Structure and evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China International Centre of Supernovae Yunnan Key LaboratoryKunming 650216China South-Western Institute for Astronomy Research Yunnan UniversityKunming 650500China

The Multi-channel Photometric Survey Telescope(Mephisto)is a real-time,three-color photometric system designed to capture the color evolution of stars and transients *** telescope system can be crucial in cosmological distance measurements of low-redshift(low-z,z■0.1)Type Ia supernovae(SNe Ia).To optimize the capabilities of this instrument,we perform a comprehensive simulation study before its official operation is scheduled to *** considering the impact of atmospheric extinction,weather conditions,and the lunar phase at the observing site involving the instrumental features,we simulate light curves of SNe Ia obtained by *** best strategy in the case of SN Ia cosmology is to take the image at an exposure time of 130 s with a cadence of 3 *** this condition,Mephisto can obtain hundreds of high-quality SNe Ia to achieve a distance measurement better than 4.5%.Given the on-time spectral classification and monitoring of the Lijiang 2.4 m Telescope at the same observatory,Mephisto,in the whole operation,can significantly enrich the well-calibrated sample of supernovae at low-z and improve the calibration accuracy of high-z SNe Ia.

关键词： (stars:)supernovae:general (cosmology:)cosmological parameters telescopes

The petroleum system:a new classification scheme based on reservoir qualities

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Petroleum Science 2019年第2期16卷 229-251页

作者： Jing-Zhou Zhao Jun Li Wei-Tao Wu Qing Cao yu-Bin bai Chuang er School of earth Sciences and engineering Xi'an Shiyou University Shaanxi Key Laboratory of Petroleum Accumulation Geology Xi'an Shiyou University

A new classification of petroleum systems(PSs) based on reservoir qualities is proposed. We classify PSs into the following three basic types:(1) source-rock petroleum system(SPS);(2) tight-reservoir or tight petroleum system(TPS);and(3) conventional-reservoir or conventional petroleum system(CPS). The CPS is a PS in which hydrocarbons accumulate in conventional reservoirs, and all the essential elements and processes are significant and indispensable. Oil and gas accumulations are geographically discrete and therefore exist as discontinuous accumulations. The TPS is a PS where hydrocarbons accumulate in tight reservoirs and the source rock, reservoir, seal, migration, and trap are also indispensable,but the traps are mostly non-anticlinal and the accumulations are primarily quasi-continuous and secondarily discontinuous. The SPS is a PS where both hydrocarbon generation and accumulation occurred in source rocks and traps and migration are unnecessary or inconsequential; the hydrocarbon distribution is extensive and continuous and has no distinct boundaries. The aforementioned three PSs can be derived from a common hydrocarbon source kitchen and are closely linked in terms of their formation and distribution. Therefore, to maximize the exploration efficiency, a comprehensive study and different strategies are needed by considering the SPS, TPS, and CPS as parts of a greater whole.

关键词： Petroleum system Classification Conventional petroleum system Unconventional petroleum system Source-rock petroleum system Tight petroleum system

Dwell Time of Particles in Tunneling Barriers of Arbitrary Shape

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Chinese Physics Letters 1998年第12期15卷 862-864页

作者： bai er-juan SHU Qi-qing Institute of Applied Nuclear Technology Shenzhen UniversityShenzhen 518060 School of Science Shenzhen UniversityShenzhen 518060

For a one-dimensional barrier of arbitrary shape,an expression of the dwell time of tunneling particles has been obtained by subdividing it into infinitesimal rectangular barrier elements and then summing the dwell times spent by particles inside the barrier elements,and the dwell times in a parabolic potential barrier were *** results show that the dwell times are almost independent of the barrier width as it is greater than a characteristic width *** can be ascribed that in the width range beyond Wc,the tunneling probabilities through the barrier elements are very small,thus the times taken to tunnel through them make little contribution to the summation of the dwell times in all the barrier elements.

关键词： barrier tunneling beyond

The enhancement of performance and imbibition effect of slickwater-based fracturing fluid by using MoS_(2)nanosheets

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Petroleum Science 2023年第4期20卷 2187-2201页

作者： hang Xu yuan Li Guo-Lin yu Sa-Sa Yang Bo-Jun Li Fu-Jian Zhou er-Dong Yao hao bai Zhi-yu Liu Unconventional Petroleum Research Institute China University of Petroleum(Beijing)Beijing102249China National Key Laboratory of Petroleum Resources and engineering China University of Petroleum(Beijing)Beijing102249China

Slickwater-based fracturing fluid has recently garnered significant attention as the major fluid for volumetric fracturing;however,lots of challenges and limitations such as low viscosity,poor salt tolerance,and possible formation damage hinder the application of the conventional simple slickwater-based fracturing *** addition,nanomaterials have proven to be potential solutions or improvements to a number of challenges associated with the *** this paper,molybdenum disulfide(MoS_(2))nanosheets were chemically synthesized by hydrothermal method and applied to improve the performance of conventional slickwater-based fracturing ***,the microstructure characteristics and crystal type of the MoS_(2)nanosheets were analyzed by SeM,eDS,TeM,XPS,and Raman spectroscopy ***,a series of evaluation experiments were carried out to compare the performance of MoS_(2)nanosheet-modified slickwater with the conventional slickwater,including rheology,drag reduction,and sand ***,the enhanced imbibition capacity and potential mechanism of the nanosheet-modified slickwater were systematically *** results showed that the self-synthesized MoS_(2)nanosheets displayed a distinct ultrathin flake-like morphology and a lateral size in the range of tens of *** the nano-composites,each MoS_(2)nanosheet plays the role of cross-linking point,so as to make the spatial structure of the entire system more ***,nanosheet-modified slickwater demonstrates more excellent properties in rheology,drag reduction,and sand *** nanosheet-modified slickwater has a higher apparent viscosity after shearing 120 min under 90℃ and 170 s^(−1).The maximum drag reduction rate achieved 76.3%at 20℃,and the sand settling time of proppants with different mesh in the nano-composites was *** imbibition experiments showed that the gel-breaking fluid of nanosheet-modified slickwater exhibited excellent capability of

关键词： Slickwater-based fracturing fluid MoS_(2)nanosheet Performance evaluation spontaneous imbibition Climbing film

enhanced energy-storage performance in a flexible film capacitor with coexistence of ferroelectric and polymorphic antiferroelectric domains

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Journal of Materiomics 2022年第2期8卷 375-381页

作者： Xiaokuo er Peng Chen Jiesen Guo yuxuan Hou Xiaobo yu Pingping Liu Yang bai Qian Zhan School of Materials Science and engineering University of Science and Technology BeijingBeijing100083China School of Mathematics and Physics China University of Geosciences BeijingBeijing100083China Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing100083China

Advances in flexible electronics are driving dielectric capacitors with high energy storage density toward flexibility and *** the present work,an all-inorganic thin film dielectric capacitor with the coexistence of ferroelectric(Fe)and antiferroelectric(AFe)phases based on Pb_(0.96)La_(0.04)(Zr_(0.95)Ti_(0.05))O_(3)(PLZT)was prepared on a 2D fluorophlogopite mica substrate via a simple one-step *** flexible capacitor exhibits a high recoverable energy density(U_(rec))of z 44.2 J/cm^(3),a large electric breakdown strength(e BDS)of 3011 kV/cm,excellent frequency stability(500 Hz-20 kHz)and high thermal stability over 30-190℃.It also demonstrates an outstanding bending endurance,which can maintain a high energy storage performance under various bending radii(R=2-10 mm)or 103 repeated bends at 4 *** Fe phase is stable near the film surface and the interface with the bottom *** AFe phase with multi-domains has incommensurate modulation structures with super-periodicity of 6.5,6.9 and *** indicates that the PLZT/LNO/F-Mica capacitor has high potential for energy storage application and may provide great opportunities for exploring new energy storage materials.

关键词： Flexible dielectric capacitor Thermal stability Bending endurance energy storage

extraction of coal-tar pitch using NMP/ILs mixed solvents

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Science China Chemistry 2014年第12期57卷 1760-1765页

作者： HUANG Jin Cheng LI Chun Shan bai Lu NIe Yi WANG er Qiang He yu Jian ZhaNG Suo Jiang School of Chemistry and Chemical engineering University of Chinese Academy of Sciences Beijing Key Laboratory of Ionic Liquids Clean Process State Key Laboratory of Multiphase Complex SystemsInstitute of Process Engineering Chinese Academy of Sciences

Coal-tar pitch(CP)is a promising carbon raw material for producing needle coke,carbon fiber *** processing,the H/C ratio,ash content,and quinoline insoluble(QI)in the CP are the key factors that influence the material *** this study,NMP was selected to extract CP first;then[BMIM]Cl/NMP mixed solvent was used;and finally a series of ionic liquids(ILs)mixtures with NMP were developed for the extraction of CP to obtain the refined *** extracts were analyzed via elemental analysis,TGA,FT-IR,and *** indicate that different NMP/IL mass ratios or different kinds of ILs have impact on the extraction *** relationship of the hydrogen to carbon(H/C)ratio changed with different solvents and QI extracts were *** showed that the H/C ratios changed little between NMP extracts and could be adjusted by changing the NMP/ILs mass ratio or using different *** extracts are suitable for preparation mesophase pitch because of no ash content,low QI,and appropriate H/C *** a result,NMP can be used to refine *** addition,[BMIM]Cl is good mixed with NMP for CP extraction,because it can obtain a relatively high yield under the same extraction conditions.

关键词： coal-tar pitch ionic liquid NMP extraction H/C

effect of group size and regrouping on physiological stress and behavior of dairy calves

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Journal of Integrative Agriculture 2023年第3期22卷 844-852页

作者： Lyu Jing WANG Chao ZhaO Xun-wu MIAO er-yu WANG Zhi-peng XU yuan bai Xiu-juan BAO Jun College of Animal Science and Technology Northeast Agricultural UniversityHarbin 150030P.R.China College of Wildlife and Protected Area Northeast Forestry UniversityHarbin 150040P.R.China

Mixing or regrouping of calves from different pens is a common animal management practice on the farm, which frequently occurs after weaning and has a negative effect on calve welfare. Social integration before regrouping may relieve stresses, but more evidences are needed to verify this hypothesis. The present study aimed to investigate acute physiological and behavioral variations of individually-or group-housed calves after being introduced into a mixed group. A total of 132 postnatal calves were randomly divided into groups of 1, 3, 6 and 12 animals(S, G3, G6, and G12;6 replicates in each group) until 59 days of age. At 60 days of age, every two replicates from different groups(S, G3, G6 and G12)were introduced in a larger pen which containing 44 of the aboved experimental calves. Before and after regrouping,physiological parameters of stress, including heart rate(HR), saliva cortisol(S-CORT), saliva secretory immunoglobulin A(SIgA), interleukin-2(IL-2), interleukin-6(IL-6), tumor necrosis factor-α(TNF-α) levels, and behavioral responses were recorded. After regrouping, HR and S-CORT increased immediately(Per(Pevels of such molecules were found in S calves compared to those in group-housed calves. Levels of SIgA and IL-2 were decreased(Pe lowest(Pes were found in S calves compared to those in group-housed calves. In addition, the introduced calves displayed a distinct behavior, including altered active and rest time, which was associated with negative emotions triggered by the novel surroundings. Allogrooming, play, exploration behaviors and lying time were increased significantly(Ped calves than those in S calves. Conversely, self-grooming, aggressive behaviors, standing and walking time were increased(Pes than those in group-housed calves. These findings suggest that individually-housed calves may be more susceptible to stressors arising from regrouping than grouphoused c

关键词： calf regrouping group size behavior stress welfare