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Mathematical modeling and simulations of stress mitigation by coating polycrystalline particles in lithium-ion batteries

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 947-962页

作者： N.IQBAL j.CHOI S.F.SHAH C.lee S.lee Department of Mechanical Roboticsand Energy EngineeringDongguk University-SeoulSeoul 04620Republic of Korea

A chemo-mechanical model is developed to investigate the effects on the stress development of the coating of polycrystalline Ni-rich LiNixMnyCo_(z)O_(2)(x≥0.8)(NMC)particles with poly(3,4-ethylenedioxythiophene)(PEDOT).The simulation results show that the coating of primary NMC particles significantly reduces the stress generation by efficiently accommodating the volume change associated with the lithium diffusion,and the coating layer plays roles both as a cushion against the volume change and a channel for the lithium transport,promoting the lithium distribution across the secondary particles more ***,the lower stiffness,higher ionic conductivity,and larger thickness of the coating layer improve the stress *** paper provides a mathematical framework for calculating the chemo-mechanical responses of anisotropic electrode materials and fundamental insights into how the coating of NMC active particles mitigates stress levels.

关键词： lithium-ion battery(LIB) polycrystalline particle coating finite element simulation Ni-rich LiNixMnyCo_(z)O_(2)(x>0.8)(NMC)

Integrating innovations:a qualitative analysis of referral non-completion among rapid diagnostic test-positive patients in Uganda’s human African trypanosomiasis elimination programme

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Infectious Diseases of Poverty 2018年第1期7卷 844-859页

作者： Shona j.lee jennifer j.Palmer Centre of African Studies University of EdinburghGeorge SquareEdinburgh EH89LDUK Health in Humanitarian Crises Centre London School of Hygiene&Tropical MedicineKeppel StreetLondon WC1E 7HTUK.

Background:The recent development of rapid diagnostic tests(RDTs)for human African trypanosomiasis(HAT)enables elimination programmes to decentralise serological screening services to frontline health ***,patients must still undertake multiple onwards referral steps to either be confirmed or discounted as *** surveillance thus relies not only on the performance of diagnostic technologies but also on referral support structures and patient *** study explored why some RDT-positive suspects failed to complete the diagnostic referral process in west Nile,***:Between August 2013 and june 2015,85%(295/346)people who screened RDT-positive were examined by microscopy at least once;10 cases were *** interviewed 20 RDT-positive suspects who had not completed referral(16 who had not presented for their first microscopy examination,and 4 who had not returned for a second to dismiss them as cases after receiving discordant[RDT-positive,but microscopy-negative results]).Interviews were analysed thematically to examine experiences of each step of the referral ***:Poor provider communication about HAT RDT results helped explain non-completion of referrals in our *** patients were unaware they were tested for HAT until receiving results,and some did not know they had screened *** HAT testing and treatment is free,anticipated costs for transportation and ancillary health services fees deterred *** expected a positive RDT result would lead to HAT *** results that failed to provide a definitive diagnosis without further testing led some to question the expertise of health *** the four individuals who missed their second examination,complying with repeat referral requests was less attractive when no alternative diagnostic advice or treatment was ***:An RDT-based surveillance strategy that relies on referral through all levels of the health system is inevitably sub

关键词： Human African trypanosomiasis Sleeping sickness Uganda Passive screening Diagnostics Case detection Referral completion Rapid diagnostic tests Elimination

Effect of compressibility on the hypervelocity penetration

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Acta Mechanica Sinica 2018年第1期34卷 82-98页

作者： w.j.Song X.w.Chen P.Chen Department of Mechanics and Engineering Science College of Engineering Peking University Advanced Research Institute for Multidisciplinary Science Beijing Institute of Technology The State Key Lab of Explosion Science and Technology Beijing Institute of Technology Centre for Applied Physics and Technology (CAPT) Peking University

we further consider the effect of rod strength by employing the compressible penetration model to study the effect of compressibility on hypervelocity ***, we define different instances of penetration efficiency in various modified models and compare these penetration efficiencies to identify the effects of different factors in the compressible model. To systematically discuss the effect of compressibility in different metallic rod-target combinations, we construct three cases, i.e., the penetrations by the more compressible rod into the less compressible target, rod into the analogously compressible target, and the less compressible rod into the more compressible target. The effects of volumetric strain, internal energy, and strength on the penetration efficiency are analyzed simultaneously. It indicates that the compressibility of the rod and target increases the pressure at the rod/target interface. The more compressible rod/target has larger volumetric strain and higher internal energy. Both the larger volumetric strain and higher strength enhance the penetration or anti-penetration ability. On the other hand, the higher internal energy weakens the penetration or anti-penetration ability. The two trends conflict, but the volumetric strain dominates in the variation of the penetration efficiency, which would not approach the hydrodynamic limit if the rod and target are not analogously compressible. However, if the compressibility of the rod and target is analogous, it has little effect on the penetration efficiency.

关键词： Compressibility Hypervelocity penetration Equation of state(EOS) Shockwave Bernoulli equation

Glass-forming Ability and Corrosion Resistance of Zr—Cu—Al—Co Bulk Metallic Glass

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journal of Materials Science & Technology 2016年第4期32卷 349-354页

作者： w.Zhou w.P.weng j.X.Hou Shagang School of Iron and Steel Soochow University

Investigations were carried out to examine the effects of Co addition on the glass-forming ability （GFA） and corrosion resistance of Zr46Cu46AI8 bulk metallic glass in chloride-containing solution. It is found that the GFA of （Zr46Cu46Al8）100-xCox （x = 0, 1, 2, and 4 at.%） alloys reduces with the increase in Co content and correlates well with the parameters, such as the supercooled liquid region width ATx, the reduced glass transition temperature Trg and γ. The corrosion resistance is however found to be enhanced with the in- crease in Co concentration. The addition of Co causes the enrichment of Zr and Al, but depletes Cu in the surface films, which effectively enhances the corrosion potential and lowers the corrosion current density.

关键词： Bulk metallic glassCo-additionGlass-forming abilityCorrosion resistance

Effect of environments and normal loads on tribological properties of nitrided Ni(45)(FeCoCr)(40)(AlTi)(15)high-entropy alloys

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journal of Materials Science & Technology 2020年第7期42卷 85-96页

作者： L.w.Lan X.j.wang R.P.Guo H.j.Yang j.w.Qiao Research Center for High-Entropy Alloys College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan030024China

The tribological properties of nitrided Ni(45)(FeCoCr)(40)(AlTi)(15)high-entropy alloys(HEAs)were investigated in air and simulated acid rain under different normal loads(5,7,10,and 12 N)at ambient *** results revealed that as-cast HEAs were only composed of FCC phase,while the volume fraction of FCC phase in the nitrided alloys was significantly ***,the hard phases of AIN,CrN,Fe4 N,and TiN phases were formed in the nitrided *** thickness of the nitriding layer was about 8.4μ*** hardness increased from 8.7 GPa in as-cast alloys to 14.5 GPa in the nitrided *** addition,under the same conditions,the friction coefficient of the nitrided alloys was higher than that of as-cast alloys,but the wear rate was generally lower than that of as-cast ***,the wear rate of the nitrided alloys was the lowest in acid rain due to the lubrication,cleaning,and cooling in the liquid *** air,dominating wear mechanisms in as-cast and nitrided alloys were abrasive,delamination,and adhesive ***,the wear mechanism of as-cast and nitrided alloys in acid rain was mainly abrasive and corrosion wears.

关键词： Abrasive wear Hardness Corrosive wear Microstructure wear mechanism

Relationships between regulated DBPs and emerging DBPs of health concern in U.S. drinking water

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journal of Environmental Sciences 2022年第7期34卷 161-172页

作者： Stuart w.Krasner Ai jia Chih-Fen T.lee Raha Shirkhani joshua M.Allen Susan D.Richardson Michael j.Plewa Metropolitan water District of Southern California Water Quality LaboratoryCA 91750USA Department of Chemistry and Biochemistry University of South CarolinaSC 29208USA Department of Crop Sciences University of Illinois at Urbana-ChampaignIL 61801USA Safe Global water Institute University of Illinois at Urbana-ChampaignIL 61801USA

A survey was conducted at eight U.S. drinking water plants, that spanned a wide range of water qualities and treatment/disinfection practices. Plants that treated heavily-wastewaterimpacted source waters had lower trihalomethane to dihaloacetonitrile ratios due to the presence of more organic nitrogen and HAN precursors. As the bromide to total organic carbon ratio increased, there was more bromine incorporation into DBPs. This has been shown in other studies for THMs and selected emerging DBPs(HANs), whereas this study examined bromine incorporation for a wider group of emerging DBPs(haloacetaldehydes, halonitromethanes). Moreover, bromine incorporation into the emerging DBPs was, in general, similar to that of the THMs. Epidemiology studies that show an association between adverse health effects and brominated THMs may be due to the formation of brominated emerging DBPs of heath concern. Plants with higher free chlorine contact times before ammonia addition to form chloramines had less iodinated DBP formation in chloraminated distribution systems, where there was more oxidation of the iodide to iodate(a sink for the iodide) by the chlorine. This has been shown in many bench-scale studies(primarily for iodinated THMs), but seldom in full-scale studies(where this study also showed the impact on total organic iodine. Collectively, the THMs, haloacetic acids, and emerging DBPs accounted for a significant portion of the TOCl, TOBr, and TOI;however, ~50% of the TOCl and TOBr is still unknown. The correlation of the sum of detected DBPs with the TOCl and TOBr suggests that they can be used as reliable surrogates.

关键词： Disinfection by-products Total organic bromine Total organic iodine Trihalomethanes Haloacetonitriles Haloacetaldehydes Iodo-trihalomethanes Iodoacetic acids

Microstructure and mechanical optimization of probeless friction stir spot welded joint of an Al-Li alloy

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journal of Materials Science & Technology 2018年第10期34卷 1739-1746页

作者： Q. Chu w.Y. Li X.w. Yang j.j. Shen A. Vairis w.Y. Feng w.B. wang State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding Technologies Northwestern Polytechnical University Xi'an710072 China Helmholtz-Zentrum Geesthacht Institute of Materials Research Materials Mechanics Geesthacht 21502 Germany Mechanical Engineering Department TEl of Crete Heraklion Crete 71004 Greece China PSw Center Beijing 100024 China

In this work, a third generation AI-Li alloy has been successfully spot welded with probeless friction stir spot welding （P-FSSw）, which is a variant of conventional friction stir welding. The Box-Behnken exper-imental design in response surface methodology （RSM） was applied to optimize the P-FSSw parameters to attain maximum tensile/shear strength of the spot joints. Results show that an optimal failure load of 7.83 kN was obtained under a dwell time of 7.2 s, rotation speed of 950 rpm and plunge rate of 30 mm/rain. Sufficient dwell time is essential for heat conduction, material flow and expansion of the stir zone to form a sound joint. Two fracture modes were observed, which were significantly affected by hook defect. In addition to mechanical testing, electron backscattering diffraction （EBSD） and differential scanning calorimetry （DSC） were used for microstructure evolution and property analysis. The precipitation of GP zone and AI3Li as well as the ultrafine grains were responsible for the high microhardness in the stir zone.

关键词： Probeless friction stir spot welding Precipitation Mechanical property Fracture mechanism

Design of logic process based low-power 512-bit EEPROM for UHF RFID tag chip

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journal of Central South University 2010年第5期17卷 1011-1020页

作者：金丽妍 lee j H KIM Y H Department of Electronic Engineering Changwon National University

A 512-bit EEPROM IP was designed by using just logic process based *** limit the voltages of the devices within 5.5 V,EEPROM core circuits,control gate(CG) and tunnel gate(TG) driving circuits,DC-DC converters:positive pumping voltage(VPP=4.75 V) ,negative pumping voltage(VNN=4.75 V) ,and VNNL(=VNN/2) generation circuit were *** addition,switching powers CG high voltage(CG_HV) ,CG low voltage(CG_LV) ,TG high voltage(TG_HV) ,TG low voltage(TG_LV) ,VNNL_CG and VNNL_TG switching circuit were supplied for the CG and TG driving ***,a sequential pumping scheme and a new ring oscillator with a dual oscillation period were *** reduce a power consumption of EEPROM in the write mode,the reference voltages VREF_VPP for VPP and VREE_VNN for VNN were used by dividing VDD(1.2 V) supply voltage supplied from the analog block in stead of removing the reference voltage generators.A voltage level detector using a capacitive divider as a low-power DC-DC converter design technique was *** result shows that the power dissipation is 0.34μw in the read mode,13.76μw in the program mode,and 13.66μw in the erase mode.

关键词： electrically erasable programmable read-only memory (EEPROM) logic process DC-DC converter ring oscillator sequential pumping scheme dual oscillation period radio frequency identification (RFID)

Extending the Relational Model to Deal withProbabilistic Data

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journal of Computer Science & Technology 2000年第3期15卷 230-240页

作者：马宗民 ZHANG w.j MA w.Y CityUniversityofHongKong KowloonHongKongP.R.China

According to the soundness and completeness of information in databases, the expressive form and the semantics of incomplete information are discussed in this paper. On the basis of the discussion, the current studies on incomplete data in relational databases are reviewed. In order to represent stochastic uncertainty in most general sense in the real world, probabilistic data are introduced into relational databases. An extended relational data model is presented to express and manipulate probabilistic data and the operations in relational algebra based on the extended model are defined in this paper.

关键词： incomplete information uncertain information extended relational model probabilistic data relational algebra