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comparative Study on Shearing Edge Quality Influence of the change of Tool Geometry in Fine-Blanking for Non-homogeneous Materials

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厦门大学学报（自然科学版） 2002年第S1期41卷 117-118页

作者： y c leung L c chan T c Lee Department of Industrial and Systems Engineering the Hong Kong Polytechnic UniversityDepartment of Industrial and Systems Engineering the Hong Kong Polytechnic UniversityDepartment of Industrial and Systems Engineering the Hong Kong Polytechnic University Hong Kong ChinaHong Kong ChinaHong Kong China

Excellent quality of shearing edge implies that a s mo oth cutting edge without tearing will be observed on the whole edge surface. Thi s is one of the most significant features of the Fine-blanking process. To achi eve such a superb blanking edge quality in fine-blanking, there actually involv es quite a large number of factors, such as blanking speed, processing material, product shape, lubrication and tool geometry, to be considered simultaneously d uring the operation. Nevertheless, the thorough investigations on different effe cts of those critical factors for different kinds of popular and applicable mate rial are rare and limited. Thus, the objective of this paper is mainly focused o n the study of the quality influence of tool geometry change in fine-blanking f or non-homogeneous materials. However, the most obvious change of the tool geo metry during the operation will be the essential variation of the nose radius of the punch. This is because the nose radius usually seriously deteriorates with the increasing service period in mass production which eventually causes the ent irely lose of the specific features of the fine-blanking process. Therefore, a tailor-made experimental study was carried out to investigate the relationship between the punch nose radius and the shearing edge quality, such as blanked edg e finish, burr height and die-roll height, during fine-blanking for different types of material. Five punches with each specified nose radius (Rp), 0.00 mm, 0.25 mm, 0.50 mm, 0.75 mm and 1.00 mm, and four kinds of blanking material ( Mil d steel SS400, Stainless steel AISI316L, copper alloy UNSc16200 and Aluminium al loy AA6063 ) were employed throughout the study. Subsequently, features of the s heared edge surfaces and data of each experiment were observed and captured for further analysis in this research. consequently, findings show that an increase of punch nose radius would produce a higher percentage of fracture of blanked ed ge and increase the

关键词： fine-blanking tool geometry shearing edge qual ity

compressive properties of a novel slurry-infiltrated fiber concrete reinforced with arc-shaped steel fibers

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第6期24卷 543-556页

作者： Hedong LI yabiao LI yunfeng PAN P.L.NG christopher k.y.leung Xin ZHAO School of civil Engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou 310018China Department of civil Engineering The University of Hong KongHong Kong 999077China Faculty of civil Engineering Vilnius Gediminas Technical UniversityVilnius LT-10223Lithuania Department of civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong Kong 999077China School of civil Engineering and Architecture Zhejiang University of Science and TechnologyHangzhou 310023China

Slurry-infiltrated fiber concrete(SIFcON)is a sort of strain hardening cement-based composite material,typically made with 5%–20%steel *** study focused on a novel type of SIFcON in which hooked-end steel fibers were replaced by arc-shaped steel *** quasi-static compressive properties of the SIFcON were first *** results suggested that using arc-shaped steel fibers in lieu of hooked-end steel fibers increased the quasi-static compressive strength by 47.1%and the strain at peak stress by 56.3%.We attribute these improvements to new crack-resisting mechanisms,namely“fiber crosslock”,“dual bridging”,and“confinement loops”,when the arc-shaped steel fibers are introduced into *** high impact resistance is a special property of SIFcON that is of practical significance,the dynamic compressive properties of arc-shaped steel fiber SIFcON were studied by using an 80-mm-diameter split Hopkinson pressure bar(SHPB).The results showed that the dynamic compressive strength,dynamic increase factor(DIF),and dynamic toughness of SIFcON all increased with the strain *** SIFcON incorporating arc-shaped steel fibers proved to have significant advantages in structural applications requiring high impact resistance.

关键词： Slurry-infiltrated fiber concrete(SIFcON) Arc-shaped steel fiber Quasi-static compressive properties Spilt Hopkinson pressure bar(SHPB) Dynamic compressive properties

Solid-state Al-air battery with an ethanol gel electrolyte

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Green Energy & Environment 2023年第4期8卷 1117-1127页

作者： yifei Wang Wending Pan kee Wah Leong Shijing Luo Xiaolong Zhao Dennis y.c.leung School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhenChina Department of Mechanical Engineering The University of Hong KongHong KongChina

Hydrogel electrolyte is especially suitable for solid-state Al-air batteries targeted for various portable applications, which may, however, lead to continuous Al corrosion during battery standby. To tackle this issue, an ethanol gel electrolyte is developed for Al-air battery for the first time in this work, by using kOH as solute and polyethylene oxide as gelling agent. The ethanol gel is found to effectively inhibit Al corrosion compared with the water gel counterpart, leading to stable Al storage. When assembled into an Al-air battery, the ethanol gel electrolyte achieves a much improved discharge lifetime and specific capacity, which are 5.3 and 4.1 times of the water gel electrolyte at 0.1 mA cm^(-2), *** studying the gel properties, it is found that a lower ethanol purity can improve the battery power output, but at the price of decreased discharge efficiency. On the contrary, a higher polymer concentration will decrease the power output, but can bring extra benefit to the discharge efficiency. As for the gel thickness, a moderate value of 1 mm is preferred to balance the power output and energy efficiency. Finally, to cater the increasing market of flexible electronics, a flexible Al-air battery is developed by impregnating the ethanol gel into a paper substrate, which can function normally even under serious deformation or damage.

关键词： Al-air battery Gel electrolyte Ethanol gel Al corrosion Polyethylene oxide

Improving maintenance efficiency and safety through a human-centric approach

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Advances in Manufacturing 2021年第1期9卷 104-114页

作者： c.y.Siew S.k.Ong A.y.c.Nee Graduate School for Integrative Sciences and Engineering National University of Singapore28 Medical DriveSingapore 117456Singapore Department of Mechanical Engineering National University of Singapore9 Engineering Drive 1Singapore 117576Singapore

This paper presents an adaptive human-machine interface(HMI)that can provide appropriate sets of digital maintenanceinformation and guidance to an operator during *** takes into consideration the expertise level of the operator and the maintenance context and *** proposed human-centric methodology considers the heart rate,intention,and expertise level of the operator,which can be captured using sensors during maintenance.A set of rules is formulated based on the sensor data to infer the state of the operator during a maintenance *** on the operator state,the adaptive HMI can augment the operator's senses using a scheme that combines visual,audio,and haptic guidance cues during maintenance to enhance the operator's ability to perceive information and perform maintenance *** schemes of visual,audio,and haptic cues are developed based on a comparison of the best practices obtained from experienced operators.

关键词： Augmented reality(AR) Ergonomics Product development Maintenance

Solution procedure of residue harmonic balance method and its applications

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Science china(Physics,Mechanics & Astronomy) 2014年第8期57卷 1581-1591页

作者： GUO ZhongJin leung A y T MA Xiaoyan School of Mathematics and Statistics Taishan University Department of civil and Architectural Engineering City University of Hong Kong

This paper presents a simple and rigorous solution procedure of residue harmonic balance for predicting the accurate approximation of certain autonomous ordinary differential *** this solution procedure,no small parameter is *** harmonic residue of balance equation is separated in two parts at each *** first part has the same number of Fourier terms as the present order of approximation and the remaining part is used in the subsequent *** corrections are governed by linear ordinary differential equation so that they can be solved easily by means of harmonic balance method *** kinds of different differential equations involving general,fractional and delay ordinary differential systems are given as numerical examples *** accurate limited cycle frequency and amplitude are *** results match well with the exact solutions or numerical solutions for a wide range of control *** with those available shows that the residue harmonic balance solution procedure is very effective for these autonomous differential ***,the present method works not only in predicting the amplitude but also the frequency of bifurcated period solution for delay ordinary differential equation.

关键词： residue harmonic balance accurate approximation fractional ordinary differential system delay ordinary differential system

Decontamination of Landfill Leachate by Soil Infiltration

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Biomedical and Environmental Sciences 1989年第4期2卷 341-357页

作者： M.H.WONG k.c.leung Department of Biology Hong Kong Baptist CollegeKowloonHong Kong Department of Biology The Chinese University of Hong KongShatinHong Kong

A soil column study was conducted to evaluate the efficiency of soil to attenuate pollutants in landfill *** was found that more than 60% of the initial alkalinity,cOD,and total nitrogen was removed after the leachate had percolated through the soil *** effi- ciencies were observed for the removal of dissolved cations,ammonia nitrogen,and nitrate *** previously percolated leachate was recirculated through the soil column,sig- nificant removal(93.6%)of ammonia nitrogen was ***,a further reduction in cOD,total nitrogen,nitrate nitrogen,and potassium was *** tests of seed germi- nation and root growth of Brassica chinensis were performed to compare the phytotoxicities of untreated,percolated,and recirculated *** phytotoxicity was reduced by both treatments,with the greatest detoxification observed in the leachate recirculation *** values ofpH and Olsen phosphorus were significantly reduced(Pcolumn *** significant increases(Pctrical conductivity(Ec),various forms of nitrogen,exchangeable sodium percentage(ESP),potassium,magnesium,zinc,and iron were ***,ESP,potassium,magnesium,sodium,iron,and various forms of nitrogen accu- mulated at the soil surface(10 cm).On the other hand,manganese was deposited at 20 to 50 cm below the soil surface of the treated column.1989 Academic ***.

关键词：刀口井群

State-of-the-art survey on digital twin implementations

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Advances in Manufacturing 2022年第1期10卷 1-23页

作者： y.k.Liu S.k.Ong A.y.c.Nee Department of Mechanical Engineering National University of Singapore9 Engineering Drive 1Singapore 117575Singapore

Digital twin(DT)has garnered attention in both industry and *** advances in big data and internet of things(IoTs)technologies,the infrastructure for DT implementation is becoming more readily *** an emerging technology,there are both potential and *** is a promising methodology to leverage the modern data explosion to aid engineers,managers,healthcare experts and politicians in managing production lines,patient health and smart cities by providing a comprehensive and high fidelity monitoring,prognostics and diagnostics *** research and surveys into the topic are published regularly,as interest in this technology is high although there is a lack of standardization to the definition of a *** to the large amount of information present in a DT system and the dual cyber and physical nature of a DT,augmented reality(AR)is a suitable technology for data visualization and interaction with *** paper seeks to classify different types of DT implementations that have been reported,highlights some researches that have used AR as data visualization tool in DT,and examines the more recent approaches to solve outstanding challenges in DT and the integration of DT and AR.

关键词： Industry 4.0 Internet of thing(IoT) cyberphysical systems Digital twin(DT) Augmented reality(AR)

Optical and thermal performance analysis of aerogel glazing technology in a commercial building of Hong kong

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Energy and Built Environment 2020年第2期1卷 215-223页

作者： c.k.leung L.Lu y.Liu H.S.cheng Jeff H.Tse Department of Building Services Engineering The Hong Kong Polytechnic UniversityZS850Block ZHung HomKowloonHong KongChina college of civil Engineering Hunan UniversityChangshaHunan 410082China Electrical and Mechanical Services Department HKSARHong KongChina

Improving the thermal insulation of glazing units is a common strategy of reducing building energy use for spacing *** paper newly examined the application of aerogel glazing technology in Hong kong by the means of laboratory testing and *** prototypes of granular aerogel glazing were selected to examine their optical properties,and the measured optical properties of aerogel were used to calculate the total window thermal performance indices.A typical 40-story commercial office building was chosen for energy simulation to compare the thermal performance of aerogel glazing with different glazing technologies in Hong *** results showed that aerogel glazing could achieve the promising reduction of window heat gain up to 57%and cooling energy up to 8.5%compared with double *** heat insulation performance of aerogel glazing is even better than the double glazing with low-E coating in Hong ***,aerogel glazing can be a good alternative of glazing to comply with the existing local Overall Thermal Transfer Value(OTTV)requirement and to reduce the building energy use for space cooling in Hong kong and other regions.

关键词： Glazing technology Aerogel glazing Building energy saving

childhood Langerhans cell histiocytosis:a disease with many faces

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World Journal of Pediatrics 2019年第6期15卷 536-545页

作者： Alexander k.c.leung Joseph M.Lam kin Fon Leong Department of Pediatrics The University of Calgaryand The Alberta Children's Hospital#20023316th Avenue NWCalgaryAB T2M 0H5Canada Department of Pediatrics University of British ColumbiaVancouverBCCanada Department of Dermatology and Skin Sciences University of British ColumbiaVancouverBCCanada Pediatric Institute Kuala Lumpur General HospitalKuala LumpurMalaysia

Background Langerhans cell histiocytosis(LcH)is a group of diseases characterized by the proliferation and accumulation of Langerhans *** presentations of LcH vary *** sources A PubMed search was conducted using clinical Queries with the key term "Langerhans cell histiocytosis".The search strategy included meta-analyses,randomized controlled trials,clinical trials,observational studies,and *** paper is based on,but not limited to,the search *** Generally,patients with LcH can be divided into two groups based on the extent of involvement at diagnosis,namely,single-system LcH and multisystem *** involvement may be unifocal or *** with isolated bone lesions typically present between 5 and 15 years of age,whereas those with multisystem LcH tend to present before 5 years of *** clinical spectrum is broad,ranging from an asymptomatic isolated skin or bone lesion to a life-threatening multisystem *** manifestations include,among others,"punched out" lytic bone lesion,seborrheic dermatitis-like erup-tion,erythematous/reddish-brown crusted/scaly papules/maculopapules/plaques/patches,and eczematous lesions,diabetes insipidus,hepatosplenomegaly,cytopenias,lymphadenopathy,and an acute fulminant disseminated multisystem condition presenting with fever,skin rash,anemia,thrombocytopenia,lymphadenopathy,and *** diagnosis is clinicopathologic,based on typical clinical findings and histologic/immunohistochemical examination of a biopsy of lesional *** cD1a,S100,and/or cD207(Langerin)immunohistochemical staining of lesional cells is required for a definitive *** waiting is recommended for patients with skin-only *** with symptomatic or refractory skin-only LcH may be treated with topical tacrolimus/corticosteroids,topical nitrogen mustard,oral methotrexate,or oral *** current recommended first-line therapy for patients with multisystem LcH i

关键词： cytopenia Diabetes insipidus Eczematous lesions Hepatosplenomegaly Lymphadenopathy Seborrheic dermatitis-like eruption