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RF channel performance assessment for a multiple carrier millimeter-wave communication system

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Progress in Natural science:Materials International 2004年第10期14卷 45-48页

作者： thomas wong Chicago Department of Electrical and Computer Engineering Illinois Institute of Technology Illinois60616 U.s.A

Channel capacity,system versatility and ease of maintenance are factors of prime concern in future generations of wire-less communication *** a result,millimeter-wave can offer considerable advantages in providing broadband *** and noise effects,including parametric fluctuations,are two significant causes for signal degradation in broadband communication *** methods to assess the performance of an RF channel in a multi-carrier system are *** measuring the forward transfer func-tion from transmitter IF to receiver IF as the frequency is swept across the channel bandwidth,characteristics such as gain flatness,chan-nel dispersion,and saturation effects are *** evaluate the ability of the communication link in preserving the synchronization be-tween two carriers,their heterodyned spectrum at the receiver IF output is *** measurement methods employ standard equip-ment and have been found to be effective when applied to a multi-carrier millimeter-wave system with over1GHz instantaneous band-width.

关键词： millimeter-wave communication system multiple carrier intermodulation carrier fluctuation synchronization

Fundamental Groups of Graphs of Cyclic subgroup separable and Weakly Potent Groups

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Algebra Colloquium 2021年第1期28卷 119-130页

作者： M.s.M.Asri k.B.wong P.C.wong Institute of Mathematical sciences Faculty of ScienceUniversity of Malaya50603 Kuala LumpurMalaysia

We give a characterization of the cyclic subgroup separability and weak potency of the fundamental group of a graph of polycyclic-by-finite groups and free-by-finite groups amalgamating edge subgroups of the form×D,w... 详细信息

关键词： HNN extensions fundamental groups of graphs of groups weakly potent residually finite

Biomedical applications of shape-memory polymers:how practically useful are they?

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science China Chemistry 2014年第4期57卷 476-489页

作者： wong Yeeshan kONG JenFong WIDJAJA Leonardus k VENkATRAMAN subbu s school of Materials science & Engineering College of Engineering Nanyang Technological University

shape-memory effect(sME) is the ability of a material to change its dimension in a predefined way in response to an external stimulus. Polymers that exhibit sME are an important class of materials in medicine, especially for minimally invasive deployment of devices. However, the rate of translation of the concept to approved products is extremely low, with mostly nitinolbased devices being approved. In this review, the general aspects of the different types of stimuli that can be used to activate sME are reviewed and sterilization issues of shape-memory polymer(sMP)-based medical devices are addressed. In addition, the general usefulness as well as the limitations of the shape-memory effect for biomedical applications are described.

关键词： shape memory biodegradable sterilization biomedical polymer

The Weakly Potency of Certain HNN Extensions of Nilpotent Groups

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Algebra Colloquium 2014年第4期21卷 689-696页

作者： k.B. wong P.C. wong Institute of Mathematical sciences University of Malaya 50603 Kuala Lumpur Malaysia

In this paper we give a characterization for certain HNN extensions oi suogroup separable groups with normal associated subgroups to be weakly potent. We then apply our result to show that certain HNN extensions of fi... 详细信息

关键词： weakly potent HNN extensions subgroup separable finitely generated nilpo-tent groups

An iterative approach to enhance the clinical learning experience in Macao nursing education

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International Journal of Nursing sciences 2019年第2期6卷 216-220页

作者： Ming Liu Yok Man Chan stephen Tee ken Gu Zhi Min Luo thomas.k.s.wong school of Health sciences Macao Polytechnic Institute Macao China Faculty of Health and social sciences Bournemouth University UK knowledge Transfer and Consultancy Company Limited Hong Kong China

Objective: The aim of this study was to reduce or eliminate the stressors to enhance nursing students' clinical learning experience through implementation of an iterative approach that developed a personalised response to student ***: A prospective cohort research design was applied to collect data from a sample of undergraduate nursing students across the four study *** iterative approach was employed to improve students' learning experience and the stressors in Nursing students scale-Chinese Version (sINs-CN) was used to measure student *** problems encountered by students were identified,refined and the responding solutions were worked out and implemented among this group of students through their first year to fourth ***: The overall sINs-CN mean score (2.17-2.82) of students was declined to a moderate ***: Having implemented iterative approach to address factors that led to stressful environments encountered by the nursing students,the overall stress score and each sub-dimension score decreased ***,it is recommended that this approach could be adopted by other colleagues in the nursing arena around the world.

关键词： Clinical Clerkship Nursing Nursing education stressors students

Femtosecond Degenerate Four-Wave-Mixing in ZnO Microcrystallite Thin Films

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Chinese Physics Letters 1999年第6期16卷 418-419页

作者： ZHANG Wei-li WANG Qing-yue CHAI Lu XING Qi-rong k.s.wong H.Wang Z.k.Tang G.k.L.wong R.Jain Ultrafast Laser Laboratory School of Precision Instruments&Optoelectronics Engineeringand Optoelectronic Information Science and Technology LaboratoryTianjin UniversityTianjin 300072 school of science Tianjin UniversityTianjin 300072 Department of Physics Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong Center for High Technology Materials University of New Mexico1313 Goddard SEAlbuquerqueNM 87106USA

Transient third-order optical nonlinearityχ^(3)of ZnO microcrystallite thin films is measured at various temperatures by using femtosecond degenerate ***-temperature excitonic enhancement of is *** magnitude ofχ^(3)ranges between 10^(-4)to 10^(-6)esu from 4.2k to room *** measuredχ^(3)response time ranging from 200 to 300 fs ultrafast for temperature down to 4.2k.

关键词： temperature. crystallite nonlinearity

Activation of human fibroblast-like synoviocytes by uric acid crystals in rheumatoid arthritis

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Cellular & Molecular Immunology 2011年第6期8卷 469-478页

作者： Da P Chen Chun k wong Lai s Tam Edmund k Li Christopher Wk Lam Department of Chemical Pathology The Chinese University of Hong KongPrince of Wales HospitalShatinNTHong KongChina Department of Clinical Laboratory Children’s Hospital of Chongqing Medical UniversityChongqingChina Department of Medicine and Therapeutics The Chinese University of Hong KongPrince of Wales HospitalNgan Shing StreetShatinNTHong KongChina Macao Institute for Applied Research in Medicine and Health Macao University of Science and TechnologyAvenida Wai LongTaipaMacaoChina

Hyperuricemia-mediated uric acid crystal formation may cause joint inflammation and provoke the destruction of joints through the activation of inflammasome-mediated innate immune ***,the immunopathological effects and underlying intracellular regulatory mechanisms of uric acid crystal-mediated activation of fibroblast-like synoviocytes(FLs)in rheumatoid arthritis(RA)have not been ***,we investigated the in vitro effects of monosodium urate crystals,alone or in combination with the inflammatory cytokines tumor-necrosis factor(TNF)-a or interleukin(IL)-1b,on the activation of human FLs from RA patients and normal control subjects and the underlying intracellular signaling mechanisms of treatment with these *** urate crystals were able to significantly increase the release of the inflammatory cytokine IL-6,the chemokine CXCL8 and the matrix metalloproteinase(MMP)-1 from both normal and RA-FLs(all P,0.05).Moreover,the additive or synergistic effect on the release of IL-6,CXCL8 and MMP-1 from both normal and RA-FLs was observed following the combined treatment with monosodium urate crystals and TNF-a or *** experiments showed that the release of the measured inflammatory cytokine,chemokine and MMP-1 stimulated by monosodium urate crystals were differentially regulated by the intracellular activation of extracellular signal-regulated kinase and c-Jun N-terminal kinase pathways but not the p38 mitogen-activated protein kinase *** results therefore provide a new insight into the uric acid crystal-activated immunopathological mechanisms mediated by distinct intracellular signal transduction pathways leading to joint inflammation in RA.

关键词： cytokines fibroblast-like synoviocytes rheumatoid arthritis signal transduction uric acid

A randomized controlled trial of topical tea tree preparation for MRsA colonized wounds

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International Journal of Nursing sciences 2014年第1期1卷 7-14页

作者： Rainbow L.P.Lee Polly H.M.Leung thomas.k.s.wong school of Nursing The Hong Kong Polytechnic UniversityHong Kong Department of Health Technology and Informatics The Hong Kong Polytechnic UniversityHong Kong Faculty of Health and social sciences The Hong Kong Polytechnic UniversityHong Kong

Background:The prevalence of MRsA(Methicillin-resistant staphylococcus aureus)colonized wounds in home care residents is expected to grow continuously as a result of the substantial proportion of older people requiring institutionalized care due to chronic disease and declining functional status,which contribute to more frequent skin breakdown and wound *** tree oil has been claimed to have anti-bacterial,analgesic and anti-inflammatory effects that have been suggested in many in-vitro studies to have good efficacy against *** aims of this study were to evaluate the effectiveness of 10%topical tea tree preparation to eradicateMRsA and to ascertain its influence on wound healing forMRsA-colonized ***:It was a randomized controlled trial,single-blind *** with stage II or above MRsA-colonized wounds and who had given their informed consent formed the *** determined sample sizewasbasedonthe effect size of our previouspilot study,whichwas *** outcome measurements were taken for the MRsA bacterial count and wound healing condition at baseline and at 1-week intervals during the 4-week dressing intervention ***:Thirty-two participants were recruited from two non-government nursing homes,16 in the control group and 16 in the tea tree oil *** control group residents received routine saline gauze dressing,while the tea tree oil group residents received the 10%topical tea tree preparation *** the tea tree oil group,all chronic wounds that had previously been delayed in healing were healed within 28 days without adverse *** was also completely eradicated in 14(87.5%)out of 16 wounds in the group receiving the 10%topical tea tree preparation.

关键词： MRsA Topical tea tree preparation Wounds

Tribological behavior of lubricant-impregnated porous polyimide

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Friction 2024年第4期12卷 711-725页

作者： Jinbang LI Ningning ZHOU Janet s.s.wong school of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China Beijing key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms Beijing Institute of Control EngineeringBeijing 100029China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

Porous materials impregnated with lubricants can be used in conditions where limited lubricant is *** this work,three porous polyimides(PPI)with different densities were ***(PAO)impregnated PPI(iPPI)discs were rubbed against steel and sapphire *** operando observations of the iPPI-sapphire contacts show that oil is released under an applied load,forming a meniscus around *** at the outlet is created at high sliding *** amount of released oil increases with increasing PPI *** moduli,E*,estimated based on the actual contact size show that trapped oil in iPPIs contributes to load *** higher speeds,tribological rehydration of the contact occurs in low density iPPI,with that E*rises with *** high density PPIs,high speeds give a constantly high E*which is limited by the viscoelastic properties of the PPI network and possibly the rate of oil *** of iPPI-steel contacts is governed by the mechanical properties of the PPI,the flow of the lubricant,and the roughness of the PPI *** low-and medium-density(highly porous,high roughness)PPIs,large amount of oil is released,and lubrication is mainly via lubricant restricted in the contact in the pores and possibly tribological *** high density(low porosity)PPI,with lower roughness,hydrodynamic lubrication is achieved which gives the lowest *** results show that polymeric porous materials for effective lubrication require the optimization of its surface roughness,stiffness,oil flow,and oil retentions.

关键词： polyimide porous material friction mechanism polymer limited lubrication