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Nano-Micro Letters 2022年第12期14卷 432-446页

作者： Dong Seob Chung Tyler Davidson-hall Giovanni Cotella Quan Lyu Peter Chun Hany Aziz Department of Electrical and Computer engineering Waterloo Institute for NanotechnologyUniversity of Waterloo200 University Avenue WestWaterlooON N2L 3G1Canada Ipswich Research Centre Huawei Technologies Research&Development(UK)Ltd.Phoenix House(B55)Adastral ParkIpswich IP53REUK Ottawa IC Laboratory Huawei Canada19 Allstate ParkwayMarkhamON L3R 5B4Canada

ZnO nanoparticles are widely used for the electron transport layers(ETLs)of quantum dots light emitting devices(QLEDs).In this work we show that incorporating fluorine(F)into the ZnO ETL results in significant enhancement in device electroluminescence stability,leading to LT50 at 100 cd m^(−2) of 2,370,000 h in red QLED,47X longer than the control devices.X-ray photo-electron spectroscopy,time-of-flight secondary ion mass spectroscopy,photoluminescence and electrical measurements show that the F passivates oxygen vacancies and reduces electron traps in *** photoluminescence versus bias measurements and capacitance-voltage-luminance measurements reveal that the CF4 plasma-treated ETLs lead to increased electron concentration in the QD and the QD/hole transport layer interface,subsequently decreasing hole accumulation,and hence the higher *** findings provide new insights into the critical roles that optimizing charge distribution across the layers play in influencing stability and present a novel and simple approach for extending QLED lifetimes.

关键词： Colloidal quantum dots Quantum dots light emitting device Device stability Zinc oxide nanoparticles Fluorine

Design of experiment study on hardness variations in friction stir welding of AM60 Mg alloy

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Journal of Magnesium and Alloys 2018年第3期6卷 215-228页

作者： S.Richmire K.hall M.Haghshenas Department of Mechanical engineering University of North DakotaGrand ForksND 58202USA Department of Chemical engineering University of North DakotaGrand ForksND 58202USA

Identification of process parameters,their effects and contributions to the outcomes of the system using experimental approach could be a daunting,time consuming,and costly *** proper statistical methods,i.e.,Taguchi method,could significantly reduce the number of required experiments and statistical significance of the parameter can be *** stir welding is one of those welding techniques with many parameters which have different effects on the quality of the *** friction stir welding the tool rotational speed(RPM)and transverse speed(mm/min)influence the strength(i.e.,hardness distribution)of the stirred *** this study,these two factors are investigated to determine the effect they will have on the hardness in the stirred zone of the friction stir welds and how the two factors are related to one another for as-cast magnesium alloy AM60 with nominal chemical composition of Mg-(5.5-6.5)Al-(0.24-0.6)*** data was taken at three different tool rotational speeds and three different transverse *** data obtained was then analyzed using a 32 factorial design to find the contribution of these *** was determined that both tool rotational speed and transverse speed possess significant effects on the stir zone ***,the interactions between the two factors were statistically assessed.

关键词： AM60 Mg alloy Design of experiment(DOE) Statistical method Friction stir welding

Quantitative analysis of deformation in hollow cylinder tests on anisotropic clay formations

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International Journal of Mining Science and Technology 2015年第2期25卷 299-303页

作者： You Shuang Ji Hongguang Labiouse Vincent hall Stephen A. Viggiani Gioacchino School of Civil and Environment engineering University of Science & Technology Beijing Rock Mechanics Laboratory Ecole Polytechnique Fédérale de LausanneEPFL Laboritoire 3S-R Grenoble UJF/CNRS/INPG

A series of triaxial laboratory experiments are performed on thick-walled hollow cylindrical samples of boom *** aim of this testing program is to better understand the anisotropic deformation during the *** testing conditions are similar to those to be experienced by host rocks around disposal galleries for radioactive waste.X-ray computed tomography is performed at different steps for each test with the samples remaining inside the loading *** analysis of the tomography images allows of the observation of the deformation of the central *** addition,particles manual tracking and 3D volumetric digital image correlation processing methods are considered being used to analyze the particles displacements and the boundary deformation of the sample *** unsymmetrical damaged zone is induced around the hole,with a reverse deformation trend being found at the boundary after unloading,which indicates that the significant anisotropic deformation of boom clay can be induced by mechanical unloading.

关键词： Boom clay Hollow cylinder test Deformation X-ray computed tomography Particles manual tracking

Numerical modeling for rockbursts:A state-of-the-art review

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Journal of Rock Mechanics and Geotechnical engineering 2021年第2期13卷 457-478页

作者： Jun Wang Derek B.Apel Yuanyuan Pu Robert hall Chong Wei Mohammadali Sepehri School of Mining and Petroleum engineering University of AlbertaEdmontonAlbertaT6G 2R3Canada State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing400044China

As the depth of excavation increases,rockburst becomes one of the most serious geological hazards damaging equipment and facilities and even causing fatalities in mining and civil *** has forced researchers worldwide to identify different methods to investigate rockburst-related ***,some problems,such as the mechanisms and the prediction of rockbursts,continue to be studied because rockburst is a very complicated phenomenon influenced by the uncertainty and complexity in geological conditions,in situ stresses,induced stresses,*** modeling is a widely used method for investigating *** date,great achievements have been made owing to the rapid development of information technology(IT)and computer ***,it is necessary and meaningful to conduct a review of the current state of the studies for rockburst numerical *** this paper,the categories and the origin of different numerical approaches employed in modeling rockbursts are reviewed and the current usage of various numerical modeling approaches is investigated by a literature ***,a state-of-the-art review is implemented to investigate the application of numerical modeling in the mechanism study,and prediction and prevention of *** main achievements and problems are ***,this paper discusses the limitations and the future research of numerical modeling for *** approach is proposed to provide researchers with a systematic and reasonable numerical modeling framework.

关键词： Rockburst Numerical modeling Rockburst mechanism Dynamic modeling

Fitting quadrics with a Bayesian prior

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Computational Visual Media 2016年第2期2卷 107-117页

作者： Daniel Beale Yong-Liang Yang Neill Campbell Darren Cosker Peter hall University of Bath

Quadrics are a compact mathematical formulation for a range of primitive surfaces. A problem arises when there are not enough data points to compute the model but knowledge of the shape is available. This paper presents a method for fitting a quadric with a Bayesian prior. We use a matrix normal prior in order to favour ellipsoids when fitting to ambiguous data. The results show the algorithm copes well when there are few points in the point cloud,competing with contemporary techniques in the area.

关键词： geometry statistics graphics computer vision

A case history study on causation of the landslide in Santa Clara,California, USA

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Journal of Rock Mechanics and Geotechnical engineering 2015年第2期7卷 185-192页

作者： Yun Liao Sadek M. Derrega Craig A. hall Kleinfelder 1330 Broadway Suite 1200 Oakland CA 94612 USA Kleinfelder 4670 Willow Road Suite 100 Pleasanton CA 94588 USA

This paper presents a case history study on the geologic investigation and numerical modeling of areactivated landslide in the County of Santa Clara, California to identify the failure mechanism. Thelandslide occurred on an approximately 18.3-m high, north-facing slope during March 2011. The landslidemeasured about 33.5 m in width and about 51.8 m in length. Along the toe of the slope, a residentialstructure with a swimming pool was built on a cut and fill pad and there are several other structurespresent along the western side of the pad. The landslide occurred immediately to the south of theresidential building and moved northward between the County Road A and the house＇s side yard. Themovement of the landslide resulted in damaging the west-bound traffic lane of County Road A andencroached onto the paved driveway for the residential property. An investigation was performed toidentify the failure mechanism of the landslide to conclude whether Road A re-alignment by the Countyor prominent cutting performed along the lower portion of the slope by the homeowner during 2000through 2004 contributed to the reactivation of the old landslide deposit. The investigation included sitereconnaissance, reviewing available published geologic information, reviewing site-specific geologic andgeotechnical data developed by other consultants, and performing numerical modeling. The outcomes ofthe investigation indicate that the primary causation for the reactivation and failure of the subject preexistinglandslide is the prominent cutting performed along the lower portion of the slope during 2000through 2004 and water tank cut bench. The Road A re-alignment did not contribute to the reactivationof the old landslide deposit. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

关键词： Pre-existing landslide ailure mechanism Slope stability

Spatially-resolved relaxor to ferroelectric phase switching in 0.93Na_(1/2)Bi_(1/2)TiO_(3)-0.07BaTiO_(3) ceramics

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Journal of Materiomics 2022年第5期8卷 976-981页

作者： Xi Shi Udo Eckstein Yizhe Li David hall Neamul H.Khansur Department of Materials Science and engineering Friedrich-Alexander-University Erlangen-Nürnberg(FAU)ErlangenGermany Department of Materials University of ManchesterManchesterUK

In situ,spatially-resolved synchrotron X-ray diffraction was utilized to investigate the electric fieldinduced heterogenous phase transformation of nonergodic relaxor 0.93Na^(1/2)Bi^(1/2)TiO_(3)-0.07BaTiO_(3) ceramics.A Cu electrode was coated on one surface of a rectangular sample by aerosol deposition(AD),while a Pt layer was deposited on the opposite surface by sputter *** is anticipated that a different stress state and/or domain morphology should occur on the AD deposited Cu electrode side due to the particle impact-consolidation deposition *** an electric field,different sample regions,i.e.,AD,Middle,and Sputter sides,showed systematic changes in the relaxor to ferroelectric phase transition *** particular,mostgrains transformed at a sub-coercive field of 0.8 kV/mm,while the majority of thegrains only appeared to undergo transitions at a higher field(2.4 kV/mm).Also,the tetragonal phase became the dominant structure at higher field ***,bothandgrains undergo phase switching at lower fields in the region close to the AD-processed *** study indicates that the AD process-induced stress can facilitate the electric field-induced relaxor to ferroelectric phase transition,i.e.,the AD Cu side showed more significant lattice strain and domain texture than the sputter Pt side.

关键词： Relaxor ferroelectric Synchrotron X-ray diffraction Phase transformation

Towards a sustainable campus-city relationship:A systematic review of the literature

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Regional Sustainability 2022年第1期3卷 53-67页

作者： Ahmed Mohammed Sayed MOHAMMED Tetsuya UKAI Michael hall Department of Design Strategy Graduate School of DesignKyushu UniversityFukuoka819-0395Japan Architectural engineering Department Faculty of EngineeringAssiut UniversityAssiut71515Egypt

The relationship between a university and its city is considered strategical to achieve university targeted ambitions and *** university-city relationship is also encouraged for the benefit of the city,as universities unleash their respective cities’potentials to act as driving forces not only for their local communities,but also for the whole ***,maintaining a mutual relationship between the university and the city is considered essential to accomplish strategic goals for ***,the nature of this relationship is quite complex,overlapped,interconnected,and ***,this paper conducted a systematic review of the literature on university-city and campus-city relationships to evaluate recent research trends to uncover the aspects that connect universities with their respective *** search included articles published in 4 different databases from January 1990 to January 2021.A total number of 50 articles were selected in this *** findings uncovered different aspects that could help or hinder university-city relationship based on the physical and functional linkage between the campus and the ***,findings have shown that it is necessary to understand universities according to their contextual differences,as universities have shown different impacts on their respective cities in terms of their sizes and *** have also shown that the impact of the physical connection between the university and the city goes far beyond campus’s accessibility as it deeply affects students’social life as ***,decision makers,stakeholders,and university administrators need to co-design campus development process especially in the early stages to maximize the mutual benefits of campus-city *** main conclusions of this paper address several perspectives and lessons for a more sustainable campus-city relationship.

关键词： Campus-city relationship University-city relationship University engagement Stakeholders’partnership Sustainability Urbanization

Behaviour of granular matter under gravity-induced stress gradient:A two-dimensional numerical investigation

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International Journal of Mining Science and Technology 2021年第3期31卷 439-450页

作者： Ruilin Li Guoqing Zhou Pin-Qiang Mo Matthew R.hall Jun Chen Daqing Chen Shangyue Cai State Key Laboratory for Geomechanics and Deep Underground engineering China University of Mining and TechnologyXuzhou 221116China GeoEnergy Research Centre Faculty of EngineeringUniversity of NottinghamNottingham NG72RDUK School of Mechanics and Civil engineering China University of Mining and TechnologyXuzhou 221116China

Gravity is the most important load source in mining and geotechnical engineering,which causes both the stress level and stress gradient inside *** from the stress level,the influence of gravity-induced stress gradient on the behaviour of the material is still *** in-deep study on it will help to promote the understanding of material behaviour,especially for those cases related to unconventional gravity such as terrestrial ng physical modelling and extraterrestrial resource exploitation(g is the terrestrial gravitational acceleration).In this study,a high-order homogenization for granular materials is proposed at first,in which the stress gradient is drawn into the constitutive representation by adopting a representative volume element(RVE).The consolidation and shear strength behaviour of RVE are then investigated by performing numerical biaxial *** results show that all the compressibility,shear strength,shear stiffness,volumetric deformation,and critical state behaviour show a stress gradient dependence.A coupling between stress gradient,stress level,and material properties is also *** observations suggest that,besides the stress level,extra attention needs to be paid to material responses related to stress gradient during engineering practices.

关键词： Stress gradient Representative volume element Granular matter Gravitational field Discrete element method

Modeling and Assessment of Buoyancy-Driven Stratified Airflow in High-Space Industrial hall

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湖南大学学报（自然科学版） 2009年第S1期36卷 19-22页

作者： WANG Han-qing1,2,CHEN Ke1,HU Jian-jun1,3,KOU Guang-xiao2,WANG Zhi-yong2(1.School of Energy Science and engineering,Central South University,Changsha,Hunan 410083,China 2.Department of Civil engineering,Hunan University of Technology,Zhuzhou,Hunan 412008,China 3.School of Mechanical engineering,Purdue University,West Lafayette,USA) School of Energy Science and engineering Central South University Changsha 410083 China Department of Civil engineering Hunan University of Technology Zhuzhou 412008 China School of Mechanical engineering Purdue University West Lafayette United States

In industrial environment,heat sources often are contaminant sources and health threatening contaminants are mainly passive,so a detailed understanding of airflow mode can assist in work environment hygiene measurement and *** paper presented a numerical investigation of stratified airflow scenario in a high-space industrial hall with validated commercial code and experimentally acquired boundary *** upon an actually undergoing engineering project,this study investigated the performance of the buoyancy-driven displacement ventilation in a large welding hall with big components *** results have demonstrated that stratified airflow sustained by thermal buoyancy provides zoning effect in terms of clean and polluted regions except minor stagnant eddy *** competition between negative buoyant jets from displacement radial diffusers and positive buoyant plume from bulk object constitutes the complex transport characteristics under and above stratification ***,downdraft and turbulent eddy motion complicate the upper mixing zone,but the exhaust outlet plays a less important role in the whole field *** the corresponding suggestions concerning computational stability and convergence,further improvements in modelling and measurements were given.

关键词： modelling buoyancy-driven large enclosure industrial ventilation