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Additive manufacturing of high-entropy alloys by thermophysical calculations and in situ alloying

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journal of Materials Science & Technology 2021年第35期94卷 53-66页

作者： Mehmet Cagirici Pan Wang Fern Lan ng Mui Ling Sharon Nai jun Ding jun Wei Singapore Institute of Manufacturing Technology 73 Nanyang Drive637662Singapore Department of Materials Science and Engineering National University of Singapore117576Singapore

Electron beam melting(EBM)is a promising technology to manufacture various alloys with outstanding properties;however,the number of available alloys is *** propose in situ alloying to accelerate the development of advanced and novel alloys,based on thermophysical calculations and CALPHAD approach,during the EBM *** demonstrate our concept through the design and fabrication of high entropy alloys(HEAs).Three CoCrFeNiMn-xTi(x=0.18,0.50,2.00,in molar%)HEAs are ***-built HEAs achieve a homogeneous distribution of elements while forming multiphase alloys resulted from the hot powder *** topological structures formed by secondary phases contribute to an increase in the hardness of EBM-built HEAs up to 900 *** alloy design,a systematic analysis on Co Cr Fe Ni Mn-0.18 Ti HEA elucidates the microstructural evolution in *** findings provide a deep understanding of in situ alloying and pave the way to develop new alloys specific to the EBM process.

关键词： 3D printing Cost reduction Electron beam melting High entropy alloy Mechanical properties Phase prediction

Synergistic interaction of metal–acid sites for phenol hydrodeoxygenation over bifunctional Ag/TiO_2 nanocatalyst

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Chinese journal of Chemical Engineering 2019年第2期27卷 349-361页

作者： Andrew ng Kay Lup Faisal Abnisa Wan Mohd Ashri Wan Daud Mohamed Kheireddine Aroua Department of Chemical Engineering Faculty of Engineering University of Malaya Centre for Carbon Dioxide Capture and Utilization School of Science and Technology Sunway University Department of Engineering Lancaster University

The use of silver metal for hydrodeoxygenation(HDO) applications is scarce and different studies have indicated of its varying HDO activity. Several computational studies have reported of silver having almost zero turnover frequency for HDO owing to its high C\\O bond breaking energy barrier and low carbon and oxygen binding *** this work, titania supported silver catalysts were synthesized and firstly used to examine its phenol HDO activity via experimental reaction runs. BET, XRD, FESEM, TEM, EDX, ICP–OES, Pyridine-FTIR, NH_3-TPD and H_2-TPD analyses were done to investigate its physicochemical properties. Phenomena of hydrogen spillover and metal–acid site synergy were examined in this study. With the aid of TiO_2 reducible support, hydrogen spillover and metal–acid site interactions were observed to a certain extent but were not as superior as other Pt, Pd, Ni-based catalysts used in other HDO studies. The experimental findings showed that Ag/TiO_2 catalyst has mediocre phenol conversion but high benzene selectivity which confirms the explanation from other computational studies.

关键词： Silver based catalyst Physicochemical properties Hydrogen spillover Metal-acid sites Hydrodeoxygenation

FCC coprocessing oil sands heavy gas oil and canola oil. 3. Some cracking characteristics

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Green Energy & Environment 2019年第1期4卷 83-91页

作者： Siauw H.ng Nicole E.Heshka Ying Zheng Qiang Wei Fuchen Ding Natural Resources Canada CanmetENERGY Department of Chemical Engineering University of New Brunswick State Key Laboratory of Heavy Oil Processing China University of Petroleum Beij.ng Institute of Petrochemical Technology

Coprocessing of bitumen-derived feeds and biomass through a fluid catalytic cracking(FCC) route has the potential to assist in the reduction of fuel and petroleum product carbon footprints while meeting government regulatory requirements on renewable transportation fuels. This approach is desirable because green house gas(GHG) emissions for producing renewable biofuels are significantly lower than those for fossil fuels, and coprocessing can be executed using existing refining infrastructure to save capital cost. The present study investigates the specific FCC performances of pure heavy gas oil(HGO) derived from oil sands synthetic crude, and a mixture of 15 v% canola oil in HGO using a commercial equilibrium catalyst under typical FCC conditions. Cracking experiments were performed using a bench-scale Advanced Cracking Evaluation(ACE) unit at fixed weight hourly space velocity(WHSV) of 8 h^(-1), 490–530℃, and catalyst/oil ratios of 4–12 g/g. This work focuses on some cracking phenomena resulting from the presence of oxygen in the blendda lower heat requirement for cracking due to the exothermic water formation, which also entails lower hydrogen yield at a given severity. The distribution of feed oxygen in gaseous and liquid products, the mitigation in GHG emissions, and the technological and economical advantages of the coprocessing option are also discussed.

关键词： FCC coprocessing Microactivity test(MAT) unit Four-lump kinetic model Heat of formation of water vapour Carbon footprint reduction

Mandatory IFRS adoption and management forecasts: The impact of enforcement changes

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China journal of Accounting Research 2019年第1期12卷 33-61页

作者： Zhaoyang Gu jeff ng Albert Tsang School of Accountancy CUHK Business SchoolThe Chinese University of Hong Kong Schulich School of Business York University

We examine how concurrent enforcement changes affect the positive relationship between mandatory IFRS adoption and firms’ voluntary disclosure. We show that the increase in the issuance of management forecasts after IFRS adoption is smaller for firms from IFRS-mandating countries with concurrent enforcement changes than for those from countries without such changes. We find no difference in the increase of forecast informativeness between firms from IFRS-mandating countries without concurrent enforcement changes and firms from non-IFRS-mandating countries; however, firms domiciled in IFRS-mandating countries with concurrent enforcement changes exhibit a significantly smaller increase in forecast informativeness. Our findings suggest that better IFRS enforcement distinctly weakens (strengthens) the positive effect of IFRS adoption on voluntary (mandatory) disclosure.

关键词： Management forecasts Voluntary disclosure Mandatory IFRS adoption Changes in enforcement Information environment

Prediction of fracture initiation in cohesive soils based on data mining modelling and large-scale laboratory verification

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Underground Space 2024年第6期19卷 279-300页

作者： Weiping Luo Dajun Yuan Yannick Choy Hing ng Dalong jin Ping Lu Teng Wang Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of the Ministry of Education for Urban Underground Engineering Beijing Jiaotong UniversityBeijing 100044China Department of Civil and Environmental Engineering National University of SingaporeSingapore 119077Singapore

Many empirical and analytical methods have been proposed to predict fracturing pressure in cohesive *** of them take into account three to four specific influencing factors and rely on the assumption of a failure *** this study,a novel data-mining approach based on the XGBoost algorithm is investigated for predicting fracture initiation in cohesive *** has the advantage of handling multiple influencing factors simultaneously,without pre-determining a failure mode.A dataset of 416 samples consisting of 14 distinct features was herein collected from past studies,and used for developing a regressor and a classifier model for fracturing pressure prediction and failure mode classification *** results show that the intrinsic characteristics of the soil govern the failure mode while the fracturing pressure is more sensitive to the stress *** XGBoost-based model was also tested against conventional approaches,as well as a similar machine learning algorithm namely random forest ***,several large-scale triaxial fracturing tests and an in-situ case study were carried out to further verify the generalization ability and applicability of the proposed data mining approach,and the results indicate a superior performance of the XGBoost model.

关键词： Fracturing pressure Failure mode Cohesive soil Data-mining Large-scale tests

Predictors of the placebo response in a nutraceutical randomized controlled trial for depression

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journal of Integrative Medicine 2024年第1期22卷 46-53页

作者： Rosemary Arnold jenifer Murphy-Smith Chee H.ng David Mischoulon Gerard j.Byrne Chad A.Bousman Con Stough Michael Berk jerome Sarris Professorial Unit the Melbourne ClinicDepartment of PsychiatryUniversity of MelbourneRichmond 3121Australia Depression Clinical and Research Program Department of PsychiatryMassachusetts General HospitalHarvard Medical SchoolBostonMA 02115USA Faculty of Medicine Discipline of PsychiatryCentre for Clinical ResearchRoyal Brisbane&Women’s HospitalHerstonthe University of QueenslandBrisbane 4006Australia Departments of Medical Genetics PsychiatryPhysiology&Pharmacology and Community Health SciencesUniversity of CalgaryCalgaryAB T2N 1N4Canada Department of Psychiatry the University of MelbourneMelbourne 3052Australia Centre for Human Psychopharmacology Swinburne UniversityMelbourne 3122Australia The Institute for Mental and Physical Health and Clinical Translation School of MedicineBarwon HealthDeakin UniversityGeelong 3220Australia The Centre of Excellence in Youth Mental Health the University of MelbourneParkville 3052Australia Florey Institute of Neuroscience and Mental Health the University of MelbourneParkville 3052Australia NICM Health Research Institute Western Sydney UniversityWestmeadNSW 2145Australia

Objective The placebo response in depression studies is the change in symptoms amongst those who receive an inactive *** well-designed randomized controlled trials(RCTs)of depression have a high proportion of placebo responders,with little understanding as to *** present study assesses characteristics associated with the placebo response in a nutraceutical trial with a large proportion of placebo *** This is a secondary analysis of a nutraceutical depression RCT which identified no overall treatment benefit relative to placebo(n=69 in placebo group).We investigated participant characteristics such as socio-demographics,clinical features,and recruitment methods,and their association with the placebo *** genetic polymorphisms were also *** response was measured based on change in Montgomery-Asberg Depression Rating Scale *** association of these hypothesis-driven variables of interest and the placebo response was examined using linear mixed effects *** Greater levels of education,particularly pursuing post-high school education,better self-reported general health,marriage/de facto,greater improvement in the first trial week,and more failed antidepressant therapies in the current depressive episode were associated with greater placebo *** increased placebo response was not found in those recruited via social media nor in those with concomitant antidepressant *** nucleotide polymorphisms from the tryptophan hydroxylase 1(TPH1)gene(A779C and A218C)were weakly associated with greater placebo response,although the evidence was attenuated after accounting for multiple *** This is,to our knowledge,the first study within nutraceutical research for depression to assess the association between participant characteristics and variation in the placebo *** variables appeared to predict the placebo *** findings may encourage future trial design

关键词： Randomized controlled trial Placebo Depression Nutraceutical Psychiatry

Application of an amphipathic molecule at the NiO_(x)/perovskite interface for improving the efficiency and long-term stability of the inverted perovskite solar cells

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journal of Energy Chemistry 2023年第3期78卷 454-462,I0013页

作者： Guibin Shen Hongye Dong Fan Yang Xin Ren ng Xin Li Fen Lin Cheng Mu Key Laboratory of Advanced Light Conversion Materials and Biophotonics Department of ChemistryRenmin University of ChinaBeijing 100872China Solar Energy Research Institute of Singapore(SERIS) National University of SingaporeSingapore 117574Singapore State Key Laboratory of Materials Processing and Die&Mold Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina Department of Chemistry National University of Singapore3 Science Drive 3Singapore 117574Singapore

The presence of defects and detrimental reactions at NiO_(x)/perovskite interface extremely limit the efficiency performance and long-term stability of the perovskite solar cells(PSCs) based on NiO_(x).Herein,an amphipathic molecule Triton X100(Triton) is modified on the NiO_(x)*** hydrophilic chain of Triton as a Lewis base additive can coordinate with the Ni3+on the NiO_(x)surface which can passivate the interfacial defects and hinder the detrimental reactions at the NiO_(x)/perovskite ***,the hydrophobic chain of Triton protrudes from the NiO_(x)surface to prevent moisture from penetrating into the NiO_(x)/perovskite ***,the NiO_(x)/Triton-based devices(MAPbI3as absorbing layer) show superior moisture and thermal stability,retaining 88.4% and 64.3% of the initial power conversion efficiency after storage in air(40%-50% relative humidity(RH)) at 25 ℃ for 1070 h and in N2at 85℃ for 800 h,***,the efficiency increases from 17.59% to 19.89% because of the passivation defect and enhanced hole-extraction ***,the NiO_(x)/Triton-based PSCs with Cs_(0.05)(MA_(0.15)FA_(0.85))_(0.95)Pb(I_(0.85)Br_(0.15))3perovskite as the light-absorbing layer also exhibits better moisture and thermal stability compared to the control devices,indicating the viability of our *** particular note,a champion PCE of 22.35% and 20.46% was achieved for small-area(0.1 cm^(2)) and large-area(1.2 cm^(2)) NiO_(x)/Triton-based devices,respectively.

关键词： Perovskite solar cells NiO_(x) Defect passivation Long-term stability Amphipathic molecule

Using Quality Management Principles to Retain Customers and Boost Your Profits

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上海商业 2003年第6期 77-79页

作者： C. j. ng

A technique for promoting detonation transmission from a confined tube into larger area for pulse detonation engine applications

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Propulsion and Power Research 2014年第1期3卷 9-14页

作者： Navid Mehrjoo Rocco Portaro Hoi Dick ng Department of Mechanical and Industrial Engineering Concordia UniversityMontréalQCH3G 1M8Canada

A simple method of detonation transmission from a small tube to a large area is *** technique involves placing obstacles which create slight blockages at the exit of the confined tube before the planar detonation emerges into the larger space,thereby generating flow instability to promote the detonation *** this experimental study two mixtures of undiluted stoichiometric acetylene-oxygen and acetylene-nitrous oxide are *** mixtures can be characterized by a cellular detonation front that is irregular and representative of those potentially used in practical aerospace *** blockage ratio imposed by the obstacles is varied systematically to identify the optimal condition under which a significant reduction in critical pressure for transmission can be obtained.A new perturbation configuration for practical use in propulsion and power systems is also introduced and results are in good agreement with those obtained using thin needles as the blockage ratio is kept constant.

关键词： Combustion Detonation Pulse detonation engines Diffraction Perturbation Reactive flow