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Thermal Characteristics in the Cutting of Inconel 718 Superalloy Using Cw Nd:YAG Laser

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Journal of Materials Science & Technology 2010年第4期26卷 362-366页

作者： D.G. Ahn k.w. Byun M.C. kang Department of Mechanical Engineering Chosun University 375 Seosuk-dong Dong-gu Gwang-ju 501-759 Korea Hybrid Materials Solution National Core Research (NCRC) Pusan National University San 30 Changjeon-dong Keumjeong-gu Busan 609-735 Korea

The objective of the this study is to investigate the effects of cutting parameters on thermal characteristics, including practical cutting regions, the formation of the kerfwidth and the heat transfer phenomenon, in the cutting of Inconel 718 super-alloy sheets using a Cw Nd：YAG laser. From the results of the experiments, the influence of process parameters on both the practical cutting region and the kerfwidth has been examined. In addition, it has been shown that the kerfwidth of the specimen lies in the range of 0.53-0.61 mm. In order to examine characteristics of the heat transfer during the laser cutting process, a three-dimensional quasi-steady heat transfer analysis has been performed using the commercial code SYSwELD V9.0. From the results of the analysis, the influence of cutting parameters on the temperature distribution in the vicinity of the cut section has been quantitatively evaluated. Based on these results, optimal cutting conditions have been estimated.

关键词： Cw Nd:YAG laser Inconel 718 kerfwidth Quasi-steady heat transfer analysis

Synthesis and properties of poly(1-phenyl-1-octyne)s containing stereogenic and chromophoric pendant groups

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Science China Chemistry 2009年第10期52卷 1691-1702页

作者： LAM Jacky w.Y. JIM Cathy k.w. kwOk Hoi Sing Department of Chemistry The Hong Kong University of Science & Technology Center for Display Research The Hong Kong University of Science & Technology

Poly(1-phenyl-1-octyne)s containing different stereogenic and chromophoric pendants {-[(C6H13)C= C(C6H4-p-CO2-R)] n -R = [(1S)-endo]-(?)-borneyl (P3), (1R,2S,5R)-(?)-menthyl (P4), -C6H4-p-(1R,2S,5R)-(?)-menthyl (P5), 2-napthyl (P6), 4-biphenylyl (P7)} have been designed and synthesized. The polymers are prepared in moderate yields by wCl6-Ph4Sn and possess high molecular weights (M w up to 64000). The structures and properties of the polymers are characterized and evaluated by NMR, TGA, UV, CD, PL, and EL analyses. All the polymers are thermally stable and their temperatures for 5% weight loss locate in the range of 300 to 416°C under nitrogen. The energy band gaps of all the polymers are ～3.0 eV. Polymers P4 and P5 show CD absorptions associated with the helicity of the polymer segments. Excitation of the THF solutions of P3–P7 by UV irradiation gives strong blue lights of ～485 nm with quantum yields higher than 20%. The thin films of the polymers also emit in the same spectral region, indicative of little aggregation-caused quenching of light emission. Multilayer EL devices with a configuration of ITO/Polymer:PVk/BCP/Alq3/LiF/Al are constructed, which emit blue lights of ～487 nm. The maximum luminance and external quantum efficiency vary with the pendant groups, with P6 exhibiting the highest external quantum efficiency of 0.16%. The spectra stability of the EL devices is outstanding and the EL peak maximum experiences little change with the applied voltage.

关键词： chiral photoluminescence polyacetylene electroluminescence helicity

LARGE STRAIN TORSION OF AXIALLY-CONSTRAINED SOLID RUBBER BARS

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Acta Mechanica Sinica 1994年第2期10卷 136-149页

作者： P.D. wu k.w. Neale E. Van der Giessen On leave from Universite de Sherbrooke Sherbrooke Quebec Canada Laboratory for Engineering Mechanics Faculty of Mechanical Engineering and Marine Technology Delft University of Technology The Netherlands

Large strain fixed-end torsion of circular solid rubber bars is studied semi-analytically. The analyses are based on various non-Gaussian network models for rubber elasticity, some of which were proposed very recently. Results are presented in terms of predicted torque vs. twist curves and axial force vs. twist curves. In some cases, the predicted stress distributions are also given. The sensitivity of the second-order axial force to the employed models is considered. The predicted results are compared with experimental results found in the literature.

关键词： rubber network model large strain torsion

Investigation in Longitudinal Compression of wool Based Suiting Fabrics

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Journal of China Textile University(English Edition) 1999年第4期16卷 95-100页

作者： LeungMei-yi LoT.Y. DhingraR.C. Yeung k.w.

This paper describes an investigation in the fabric longi-tudinal compressibility of thirty-one suiting and trouse-ring materials using a newly developed device attached to the advanced Instron extensometer *** at-tachment was designed mainly to ensure a correct align-meat of fabric plane at the start of *** newly developed testing method,fabric longitudinalcompression curve was obtained and the results of longi-tudinal compressibility measured by two different com-pression load ranges(from 0 to 0.5 N/m width and 0 to1 N/m width)were *** addition,their rela-tionships with the fabric low-stress mechanical proper-ties measured by the kES-F system were investigatedusing statistical *** results clearly indicatedthat significant differences existed when substituting fab-ric longitudinal compressibility with fabric extensibilitymeasured using the kES-F system under a *** infiuence of yarn rotational movement in fab-ric on the longitudinal

关键词： longitudinal compressibility extensibility shear rigidity formability and bending rigidity

Assessing Sexual Function amongst Hong kong Chinese Patients with Gynecological Cancer： Translation and Validation of the Sexual Function-Vaginal Changes Questionnaire （SVQ）

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作者： k.w. Jeter.

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Clinical oncology and cancer researeh 2010年第4期7卷 230-233页

作者： ka-ming CHOw winnie k.w. SO Carmen w.H. CHAN Prince of wales Hospital Hong Kong SARChina The Nethersole School of Nursing Hong Kong SAR China The Chinese University of Hong kong Hong Kong SAR China The Chinese University of Hong kong Hong Kong SAR China.

OBJECTIVE The study aims to translate the Sexual FunctionVaginal Changes Questionnaire （SVQ） into Chinese and to establish its psychometric *** A Chinese SVQ was developed by the use of the Brislin model of translation. The content validity and semantic equivalence were assessed by an expert panel. The translated version of SVQ was administered to 75 Hong kong Chinese women who were suffered from gynecological cancer to test its psychometric *** The Chinese version of SVQ was compared to the original study for factor analysis. Internal consistency, itemtoscale correlations and test-retest reliability were high. The convergent and divergent validities supported the Chinese SVQ to CONCLUSION we conclude that the Chinese SVQ appears to be a valid, reliable and feasible disease-specific tool for the assessment of sexual function among Chinese patients.

关键词： sexual function-vaginal changes questionnaire sexual function Hong kong Chinese

Fast numerical generation and hybrid encryption of a computer-generated Fresnel holographic video sequence

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Chinese Optics Letters 2013年第2期11卷 27-31页

作者： Peter Tsang k.w.-k. Cheung T.-C. Poon Department of Electronic Engineering City University of Hong KongTat Chee AvenueKowloon Bradley Department of Electrical and Computer Engineering Virginia TechUSA Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences

Research demonstrates that a Fresnel hologram can be generated and simultaneously encrypted numerically based on a secret symmetric key formed by the maximal length sequence （M-sequence）. The method can be directly extended to encrypt a video holographic clip in a frame-by-frame manner. However, given the limited combination of signals in the family of M-sequence, hacking the secret key through trial and error can be time consuming but not difficult. In this letter, we propose a method that is difficult to crack.w.th brute force for enerypting a holographic video sequence. An M-sequence is first randomly assigned to enerypt each frame of the holographic video signal. Subsequently, the index of the selected M-sequence, which is necessary to decrypt the hologram~ is encrypted with the RSA algorithm before transmitting to the receiving end. At the receiving end, the decoder is provided with a private key to recover the index for each frame, and the corresDonding M-se（mence is used to decrvDt the encoded hologram.

关键词： Access control Computer generated holography Cryptography Personal computing Video recording

Inorganic/organic hybrid white-light phosphor for solid state illumination

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Inorganic/organic hybrid white-light phosphor for solid stat...

Evaluation of Social Perception on water Issues in Cameron Highlands （Malaysia） by Principle Factor Analysis

第五届全国稀土发光材料学术研讨会

作者： k.M. Ng k.w. Cheah Department of Physics and Centre for Advanced Luminescence Materials Hong kong Baptist University Kowloon Tong Hong Kong

white-light-emitting diode was fabricated by using near UV LED (emissionλ= 390 – 420 nm) with a novel inorganic/organic hybrid phosphor. The white-light phosphor consist of three fluorescence phosphor

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Journal of Environmental Science and Engineering 2010年第4期4卷 45-52页

作者： k.w. Tan M.B. Mokhtar Institute for Environment and Development （LESTAR1） University Kebangsaan Malaysia Selangor 43600 Malaysia

Dealing with water resources issues requires understanding of the community perception. It is important to create a communicative partnership between community and government towards sustainable water resources management. Opinion survey is an essential step to gather the point of view from local community. However, it always generates a large and complex dataset that are difficult to be interpreted by decision maker. In order to overcome this difficulty, statistical methods are applied to develop an interpretability model for decision maker. This study demonstrated the application of Descriptive Analysis and Principle Factor Analysis （PFA） to reduce the complexity of opinion survey dataset by revealing underlying information. A total of 106 respondents were interviewed; consisting of 68 male and 38 female respondents respectively. This study first applied descriptive analysis to identify the basic score for each variable, and these variables are soil erosion （68.9%）, degradation of water quality （65.1%）, degradation of freshwater ecosystem （61.0%）, water shortage （50%）, agricultural solid waste problem （46.2%）, water borne diseases （23.6%）, illegal land clearing （21.7%）, legal land clearing （15.1%）, uncontrolled river water abstraction in upstream （54.7%））, poor solid waste management （34.0%）, low awareness of local community （61.3%）, haphazard planning and development （74.5%） and administration mistake （37.0%）. Based on the PFA result, a total of four rotated factors were extracted, representing different aspects of water related issues in Cameron Highlands. Factor 1, 2, 3 and 4 were summarised to four topics namely：（1） water environment degradation caused by illegal solid waste disposal and low awareness of community, （2） agricultural development leading to negative impacts on water resources such as water shortage and ecosystem deterioration, （3） land clearing activity leading to serious land erosion （4） human health problem due to e-coli bacterial pollution an

关键词： Descriptive analysis principal factor analysis local perception water issues cameron highlands.