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Flat-end tool orientation based on rotation-minimizing frame

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Advances in Manufacturing 2019年第3期7卷 257-269页

作者： Xiang Zou Hon-yuen Tam Hai-Yin Xu Ke Shi School of Computer Science and Technology Huazhong University of Science and TechnologyWuhan 430074People's Republic of China College of Science and Engineering Department of Mechanical EngineeringCity University of Hong KongHong KongPeople's Republic of China

Well-designed tool orientation is crucial for the quality execution of five-axis machining with flat-end *** orientation can be specified in terms of tool inclination and tool tilt *** a given surface path,these aspects need to be specified for each cutter contact point along the path,because poor tool orientation choice can cause large axial acceleration of the machine tool,leading to inferior quality of the machined *** rotation-minimizing frame aims to reduce unnecessary frame rotation during *** concept has been adopted to develop tool orientation methods that allow variation in the inclination angle,the tilt angle,and both the inclination and tilt *** intention is to reduce unnecessary rotation of the tool frame as the tool follows a specified *** was conducted in the context of five-axis flat-end tool *** on these methods,tool orientation was planned along surface paths of a torus,sphere,and *** in tool orientation were always *** the perspective of reducing tool orientation changes and axial acceleration,it was demonstrated that simultaneous variation of the inclination and tilt angles based on rotation minimization provided the best results.

关键词： Five-axis machining Tool orientation Rotation-minimizing frame Numerical control

Male Advertisement Call of the Endangered Leptobrachella tengchongensis(Anura: Megophryidae) from Mount Gaoligongshan, Yunnan Province, China

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Asian Herpetological Research 2021年第2期12卷 221-227页

作者： Ho yuen YEUNG Xiangyuan HUANG Shenpin YANG Jianhuan YANG Kadcxfrie Conservation China Department Kcuioorie Farm and Botanic GardenLam Kam RoadTai PoN.T.Hong KongChina Gaoligongshan National Nature Reserve(Tengchong Bureau) Tengchong 679100YunnanChina

We present the first description of the acoustic characters of the endangered Tengchong leaf litter toad(Leptobrachella tengchongensis), aiming to inform future ecological studies of the species and taxonomic studies in the genus Leptobrachella. A total of 1179 calls, belonging to 6 adults male individuals, were recorded using TASCAM DR-40 digital sound recorder from its type locality in May 2015 and then analyzed using Raven Pro v.1.6.1 software. The advertisement call of male L. tengchongensis consists of primary advertisement call and secondary advertisement call. The primary advertisement call is invariably composed of two notes and has a call duration of 61 ± 5 ms(23–87 ms, n = 1142). The secondary advertisement call is composed of 3–10 notes(mean 5.25 ± 1.41 notes/call, n = 37) with a call duration of 90 ± 6 ms(37–127 ms, n = 37). The mean inter-call interval is 212 ± 121 ms(88–1121 ms, n = 1092). An introductory note is absent in advertisement calls and the dominant of calls is 4.1–4.8 kHz(at 20 ℃). We discuss the interspecific and intraspecific variations on advertisement calls in L. tengchongensis and among Leptobrachella species, and provide a summary on the major acoustic characters of all Leptobrachella species occurring north of the Isthmus of Kra.

关键词： acoustic analysis amphibians bioacoustics breeding ecology Leptolalax taxonomy Tengchong

An unprecedented outbreak investigation for nosocomial and community-acquired legionellosis in Hong Kong

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Chinese Medical Journal 2012年第23期125卷 4283-4290页

作者： CHENG Vincent Chi-chung WONG Samson Sai-yin CHEN Jonathan Hon-kwan CHAN Jasper Fuk-woo TO Kelvin Kai-wang POON Rosana Wing-shan WONG Sally Cheuk-ying CHAN kwok-hung TAI Josepha Wai-ming HO Pak-leung TSANG Thomas Ho-fai yuen kwok-yung Department of Microbiology Queen Mary Hospital Hong Kong China Infection Control Team Queen Mary Hospital Hong Kong China Centre for Health Protection Department of Health Hong Kong China

Background The environmental sources associated with community-acquired or nosocomial legionellosis were not always detectable in the mainland of China and Hong Kong, China. The objective of this study was to illustrate the control measures implemented for nosocomial and community outbreaks of legionellosis, and to understand the environmental distribution of legionella in the water system in Hong Kong, China. Methods We investigated the environmental sources of two cases of legionellosis acquired in the hospital and the community by extensive outbreak investigation and sampling of the potable water system using culture and genetic testing at the respective premises. Results The diagnosis of nosocomial legionellosis was suspected in a patient presenting with nosocomial pneumonia not responsive to multiple beta-lactam antibiotics with subsequent confirmation by Legionella pneumophila serogroup 1 antigenuria. High counts of Legionella pneumophila were detected in the potable water supply of the 70-year-old hospital building. Another patient on continuous ambulatory peritoneal dialysis presenting with acute community-acquired pneumonia and severe diarrhoea was positive for Legionella pneumophila serogroup 1 by polymerase chain reaction （PCR） testing on both sputum and nasopharyngeal aspirate despite negative antigenuria. Paradoxically the source of the second case was traced to the water system of a newly commissioned office building complex. No further cases were detected after shock hyperchlorination with or without superheating of the water systems. Subsequent legionella counts were drastically reduced. Point-of-care infection control by off-boiled or sterile water for mouth care and installation of water filter for showers in the hospital wards for immunocompromised patients was instituted. Territory wide investigation of the community potable water supply showed that 22.1% of the household water supply was positive at a mean legionella count of 108.56 CFU/ml （rang

关键词： outbreak nosocomial legionellosis community-acquired legionellosis

Reflective graphene oxide absorber for passively mode-locked laser operating at nearly 1μm

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Chinese Physics B 2013年第9期22卷 442-445页

作者：杨济民杨琦刘杰王勇刚 yuen H.Tsang College of Physics and Electronics Shandong Normal University State Key laboratory of Crystal Material Shandong University Department of Applied Physics and Materials Research Center The Hong Kong Polytechnic University

A low cost and simply fabricated reflective graphene oxide is successfully made. By using this absorber, as well as an end reflector, we obtain a passively mode-locked Yb：LuYSiO5 laser operating at nearly 1 p,m. When the pump power is increased up to 5.73 W, stable mode locking is achieved. The central wavelength of the laser spectrum is 1043.2 nm with a pulse duration of 5.0 ps. When the pump power reaches 8.16 W, dual-wavelength mode locking laser pulses at 1036.3 nm and 1043.5 nm are simultaneously detected.

关键词： passively mode-locked dual-wavelength laser graphene oxide Yb:LuYSi05 crystal

Acupuncture and neuroregeneration in ischemic stroke

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Neural Regeneration Research 2018年第4期13卷 573-583页

作者： Qwang-yuen Chang Yi-Wen Lin Ching-Liang Hsieh department of family medicine lin shin hospitaltaichungtaiwanchina research center for chinese medicine and acupuncture china medical universitytaichungtaiwanchina graduate institute of acupuncture science college of chinese medicinechina medical universitytaichungtaiwanchina graduate institute of integrated medicine college of chinese medicinechina medical universitytaichungtaiwanchina department of chinese medicine china medical university hospitaltaichungtaiwanchina

Acupuncture is potentially beneficial for post-stroke rehabilitation and is considered a promising preventive strategy for *** pretreatment or treatment after ischemic stroke by using appropriate electroacupuncture parameters generates neuroprotective and neuroregenerative effects that increase cerebral blood flow,regulate oxidative stress,attenuate glutamate excitotoxicity,maintain bloodbrain barrier integrity,inhibit apoptosis,increase growth factor production,and induce cerebral ischemic tolerance.

关键词： acupuncture neuroprotection neuroregeneration

Fabrication of Microlens Array and Its Application:A Review

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Chinese Journal of Mechanical Engineering 2018年第1期31卷 10-18页

作者： Wei Yuan Li-Hua Li Wing-Bun Lee Chang-yuen Chan State Key Laboratory of Ultra-precision Machining Technology Partner Laboratory in the Hong Kong Polytechnic University Shenzhen Branch of State Key Laboratory of Ultra-precision Machining Technology PolyU Shenzhen Research Institute

Microlens arrays are the key component in the next generation of 3D imaging system, for it exhibits some good optical properties such as extremely large field of view angles, low aberration and distortion, high temporal resolution and infinite depth of field. Although many fabrication methods or processes are proposed for manufacturing such precision component, however, those methods still need to be improved. In this review, those fabrication methods are categorized into direct and indirect method and compared in detail. Two main challenges in manufacturing microlens array are identified: how to obtain a microlens array with good uniformity in a large area and how to produce the microlens array on a curved surface? In order to effectively achieve control of the geometry of a microlens,indirect methods involving the use of 3D molds and replication technologies are suggested. Further development of ultraprecision machining technology is needed to reduce the surface fluctuation by considering the dynamics of machine tool in tool path planning. Finally, the challenges and opportunities of manufacturing microlens array in industry and academic research are discussed and several principle conclusions are drawn.

关键词： Microlens array Ultraprecision machining 3D image system MEMS

Successful capture of red thrombus in acute inferior ST-elevation myocardial infarction

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Journal of Geriatric Cardiology 2018年第10期15卷 647-648页

作者： Wai-Kin CHI Chi-yuen CHAN Division of Cardiology Department of Medicine and TherapeuticsPrince of Wales Hospitalthe Chinese University of Hong KongHong KongChina

A 50-year-old gentleman with past medical history of hypertension presented with acute inferior ST-segment elevation myocardial infarction (STEMI).He complained severe chest pain despite onset time was more than *** p... 详细信息

关键词： Embolic protection device Successful capture Thrombus

SEPRAN: A Versatile Finite-Element Package for a Wide Variety of Problems in Geosciences

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Journal of Earth Science 2015年第1期26卷 89-95页

作者： Arie van den Berg Guus Segal David A.yuen Department of Theoretical Geophysics Institute of Earth SciencesUtrecht University3508 TC UtrechtThe Netherlands Faculty of Electrical Engineering Mathematics and Computer ScienceTU DelftThe Netherlands Department of Earth Sciences and Minnesota Supercomputing Institute University of MinnesotaMinneapolis MN 55455USA School of Environmental Studies China University of Geosciences

Numerical modelling of geological processes, such as mantle convection, flow in porous media, and geothermal heat transfer, has become quite common with the increase in computing and the availability of usable software. Today modelling these dynamical processes entails the solving of the governing equations involving the mass, momentum, energy and chemical transport. These equations represent partial differential equations and must be solved on powerful enough computers because they require sufficient spatial and temporal resolution to be useful. We describe here the salient and outstanding features of the SEPRAN software package, developed in the Netherlands, as a case study for a robust and user-friendly soft- ware, which the geological community can utilize in handling many thermal-mechanical-chemical problems found in geology, which will include geothermal situations, where many types of partial differential equations must be solved at the same time with thermodynamical input parameters.

关键词： SEPRAN finite element package geodynamic and planetary modelling geothermal groundwater flow.

Transurethral resection of prostate for acute urinary retention is linked to shorter survival in younger men

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Asian Journal of Andrology 2019年第5期21卷 468-472页

作者： Jeremy yuen-Chun Teoh Chi-kwok Chan Maggie Haitian Wang Chi-Ho Leung Eddie Shu-Yin Chan Peter Ka-Fung Chiu Chi-Hang Yee Hon-Ming Wong Simon See-Ming Hou Chi-Fai Ng S.H.Ho Urology Centre Department of SurgeryPrince of Wales HospitalThe Chinese University of Hong KongHong KongChina Division of Biostatistics JC School of Public Health and Primary CareThe Chinese University of Hong KongHong KongChina Division of Urology Department of SurgeryNorth District HospitalHong KongChina Division of Urology Department of SurgeryAlice Ho Miu Ling Nethersole HospitalHong KongChina

It is largely unknown whether lower urinary tract symptoms(LUTS)or acute retention of urine(AROU)is linked to shorter life expectancy in *** conducted a multicenter,retrospective database analysis of patients undergoing transurethral resection of prostate(TURP)to study their *** Cox regression analysis and Kaplan-Meier analysis with stratification to age and indication of TURP were *** further performed an age-and sex-matched survival analysis with the general population using data from the Census and Statistics Department of the Hong Kong Special Administrative Region(Hong Kong,China).From January 2002 to December 2012,3496 patients undergoing TURP were included in our study,with 1764 patients in the LUTS group and 1732 patients in the AROU *** age,ischemic heart disease,cerebrovascular accident,and AROU were risk factors of *** aged80 *** to the general population,younger patients in the LUTS group appeared to have better survival(80 years,survival was similar with the general population in both the LUTS and AROU *** conclusion,AROU at young age was associated with mortality,while early detection and management of LUTS may improve survival.

关键词： acute retention of urine lower urinary tract symptoms mortality transurethral resection of prostate