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Significant annealing-induced hardening effect in nanolaminate d-nanotwinne d(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8)me dium-entropy alloy by severe cold rolling

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Journal of Materials Science & Technology 2024年第3期170卷 156-166页

作者： Shuqing Yuan Hui Fu Lei Qian chi fai cheung Xu-Sheng Yang State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518060China

Due to the easy coarsening caused by poor thermal stability,the verified annealing-induced hardening in nanograined metals can only maintain at a relatively low-temperature range.In this study,a nanolam-inated(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8)medium-entropy alloy with an average lamellae thickness of∼20 nm embedded by thinner nanotwins was fabricated by severe cold rolling to achieve superior thermal stability.Compared with the conventional nanotwinned CrCoNi with nanotwins inside ultra-fined grains,the hier-archical nanolaminated-nanotwinned(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8) exhibits a significant annealing-induced hard-ening effect,i.e.,hardness increasing from∼250 HV in the original specimen to∼500 HV in the cold-rolled status and finally∼630 HV after annealing at 600℃for 1 h.Detailed microstructure characterizations reveal that the reduced dislocation density and formation of L1_(2)ordered domain are mainly responsible for such hardening effect,which is facilitated by the effectively suppressed coarsening with annealing temperature,i.e.,slow detwinning process and well-retained low-angle nanolamellar structure.The coarsening mechanisms from the cold-rolled nanolamellae to the fully recrystallized micro-equiaxed structures under the annealing temperatures ranging from 400 to 800℃ were also elucidated by atomic observations.

关键词： Annealing-induced hardening Thermal stability Nanolaminated-nanotwinned structure CrCoNi Detwinning Grain boundary migration

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Suppression Strategy of Micro-waviness error in Ultra-precision Parallel Grinding

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Nanomanufacturing and Metrology 2022年第4期5卷 423-429页

作者： Shanshan Chen Shuming Yang chi fai cheung Lai Ting Ho Feihu Zhang Xi’an Jiaotong University 28 Xianning West RoadXi’an710049China Research Institute of Xi’an Jiaotong University ZhejiangHangzhou311215China The Hong Kong Polytechnic University Hung HomKowloon999077Hong KongChina Harbin Institute of Technology Harbin150001China

Ultra-precision parallel grinding is widely used in the machining of complex optic components with high tolerance and excellent surface finish.However,the micro-waviness raised from the relative motion error of the grinding tool is frequently involved in the grinding process despite the fine dressing and dynamic balance work carried out,which posed a remarkable impact on the surface quality and form accuracy.Therefore,it is essential to investigate the evolution mechanism of the micro-waviness error and determine a relevant strategy to suppress this kind of error.In this paper,a model of the distribution of grinding points corresponding to the relative motion error of the grinding wheel is developed by considering the phase effect.A close relationship is found between the micro-waviness geometry and the distribution of grinding points.This indicates that the phase shift is a significant parameter to determine the waviness pattern,and the uniform distribution of grinding points is beneficial to suppress the micro-waviness in parallel grinding.Finally,an error-suppression strategy is proposed by adjusting the wheel speed to maintain an appropriate phase shift to suppress the micro-waviness error.This work provides a new method to control the micro-waviness and reduce the effect of the waviness error on the surface generation.

关键词： Suppression strategy Micro-waviness Motion error Parallel grinding

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A prospective cohort of men with localized prostatecancer on active surveillance protocol in Hong Kong,china:what did we learn?

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Asian Journal of Andrology 2024年第3期26卷 245-249页

作者： Xiaobo Wu Ivan ching-Ho Ko Cindy Yeuk-Lam Hong Samuel chi-Hang Yee Jeremy Yuen-Chun Teoh Samson Yun-Sang Chan Ho-Man Tam chi-Kwok Chan chi-fai Ng Peter Ka-Fung chiu SH Ho Urology Centre Department of SurgeryFaculty of MedicineThe Chinese University of Hong KongHong KongChina.

This study aimed to report the outcomes of active surveillance(AS)in the management of low-risk prostate cancer(PCa).It recruited87 men who were prospectively followed up according to the Prostate Cancer Research International Active Surveillance(PRIAS)protocol with local adaptation at SH Ho Urology Centre,Prince of Wales Hospital,Hong Kong,china.We investigated the predictorsof disease progression and found that baseline prostate-specific antigen density(PSAD)and the presence of the highest ProstateImaging-Reporting and Data System(PI-RADS)score 5 lesion on magnetic resonance imaging(MRI)are significantly correlatedwith disease progression.Moreover,men with PSAD>0.2 ng ml^(−2)or PI-RADS 4 or 5 lesions had significantly worse upgradingfree survival compared to those with PSAD≤0.2 ng ml−2 and PI-RADS 2 or 3 lesions.The study concludes that AS is a safe andeffective management strategy for selected patients to defer radical treatment and that most disease progression can be detectedafter the first repeated biopsy.The combination of PSAD>0.2 ng ml^(−2)and PI-RADS 4 or 5 lesions may serve as a useful predictorof early disease progression and provide a guide to optimize follow-up protocols for men in different risk groups.

关键词： active surveillance cohort localized prostate cancer

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Effects of SARS-CoV-2 infection on incidence and treatment strategies of hepatocellular carcinoma in people with chronic liver disease

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World Journal of Hepatology 2024年第2期16卷 211-228页

作者： Lung-Yi Mak Matthew Shing Hin Chung Xue Li Francisco Tsz Tsun Lai Eric Yuk fai Wan Celine Sze Ling Chui Franco Wing Tak Cheng Esther Wai Yin Chan ching Lung cheung Ivan chi Ho Au Xi Xiong Wai-Kay Seto Man-Fung Yuen Carlos King Ho Wong Ian chi Kei Wong Department of Medicine The University of Hong KongHong KongChina State Key Laboratory of Liver Research The University of Hong KongHong KongChina Department of Pharmacology and Pharmacy The University of Hong KongHong KongChina Laboratory of Data Discovery for Health(D24H) Hong Kong Science and Technology ParkHong KongChina Department of Family Medicine and Primary Care The University of Hong KongHong KongChina School of Nursing The University of Hong KongHong KongChina School of Public Health The University of Hong KongHong KongChina Research Department of Practice and Policy University College LondonLondon WC1E 6BTUnited Kingdom Aston School of Pharmacy Aston UniversityBirmingham B47ETUnited Kingdom

BACKGROUND Chronic liver disease(CLD)was associated with adverse clinical outcomes among people with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection.AIM To determine the effects of SARS-CoV-2 infection on the incidence and treatment strategy of hepatocellular carcinoma(HCC)among patients with CLD.METHODS A retrospective,territory-wide cohort of CLD patients was identified from an electronic health database in Hong Kong.Patients with confirmed SARS-CoV-2 infection[coronavirus disease 2019(COVID-19)+CLD]between January 1,2020 and October 25,2022 were identified and matched 1:1 by propensity-score with those without(COVID-19-CLD).Each patient was followed up until death,outcome event,or November 15,2022.Primary outcome was incidence of HCC.Secondary outcomes included all-cause mortality,adverse hepatic outcomes,and different treatment strategies to HCC(curative,non-curative treatment,and palliative care).Analyses were further stratified by acute(within 20 d)and post-acute(21 d or beyond)phases of SARS-CoV-2 infection.Incidence rate ratios(IRRs)were estimated by Poisson regression models.RESULTS Of 193589 CLD patients(>95%non-cirrhotic)in the cohort,55163 patients with COVID-19+CLD and 55163 patients with COVID-19-CLD were included after 1:1 propensity-score matching.Upon 249-d median follow-up,COVID-19+CLD was not associated with increased risk of incident HCC(IRR:1.19,95%CI:0.99-1.42,P=0.06),but higher risks of receiving palliative care for HCC(IRR:1.60,95%CI:1.46-1.75,P<0.001),compared to COVID-19-CLD.In both acute and post-acute phases of infection,COVID-19+CLD were associated with increased risks of allcause mortality(acute:IRR:7.06,95%CI:5.78-8.63,P<0.001;post-acute:IRR:1.24,95%CI:1.14-1.36,P<0.001)and adverse hepatic outcomes(acute:IRR:1.98,95%CI:1.79-2.18,P<0.001;post-acute:IRR:1.24,95%CI:1.13-1.35,P<0.001),compared to COVID-19-CLD.CONCLUSION Although CLD patients with SARS-CoV-2 infection were not associated with increased risk of HCC,they were more likely to receive palliative treatment

关键词： SARS-CoV-2 infection Chronic liver disease Long COVID Post-COVID-19 syndrome Cirrhosis Hepatocellular carcinoma

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Friction behaviors in the metal cutting process:state of the art and future perspectives

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International Journal of Extreme Manufacturing 2023年第1期5卷 22-58页

作者： Xiaoliang Liang Zhanqiang Liu Bing Wang Chunjin Wang chi fai cheung Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE School of Mechanical EngineeringShandong UniversityJinan 250061People’s Republic of China Key National Demonstration Center for Experimental Mechanical Engineering Education Shandong UniversityJinan 250061People’s Republic of China State Key Laboratory of Ultra-Precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityKowloonHong KongPeople’s Republic of China

Material removal in the cutting process is regarded as a friction system with multiple input and output variables.The complexity of the cutting friction system is caused by the extreme conditions existing on the tool–chip and tool–workpiece interfaces.The critical issue is significant to use knowledge of cutting friction behaviors to guide researchers and industrial manufacturing engineers in designing rational cutting processes to reduce tool wear and improve surface quality.This review focuses on the state of the art of research on friction behaviors in cutting procedures as well as future perspectives.First,the cutting friction phenomena under extreme conditions,such as high temperature,large strain/strain rates,sticking–sliding contact states,and diverse cutting conditions are analyzed.Second,the theoretical models of cutting friction behaviors and the application of simulation technology are discussed.Third,the factors that affect friction behaviors are analyzed,including material matching,cutting parameters,lubrication/cooling conditions,micro/nano surface textures,and tool coatings.Then,the consequences of the cutting friction phenomena,including tool wear patterns,tool life,chip formation,and the machined surface are analyzed.Finally,the research limitations and future work for cutting friction behaviors are discussed.This review contributes to the understanding of cutting friction behaviors and the development of high-quality cutting technology.

关键词： cutting process friction behaviors material removal process contact condition

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An Investigation of Effect of Stand-Off Distance on the Material Removal Characteristics and Surface Generation in Fluid Jet Polishing

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Nanomanufacturing and Metrology 2020年第2期3卷 112-122页

作者： Chun Jin Wang chi fai cheung Lai Ting Ho Yee Man Loh State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina

Fluid jet polishing(FJP)is a versatile polishing process that has many advantages compared to other polishing processes.Stand-off distance(SOD)is one of the key parameters in flu id jet polishi ng.However,relatively little research work has been carried out to investigate its effect of SOD on material removal characteristics and surface generation in FJP.In this paper,a systematic investigation of the effect of SOD on the tool influence function and surface topography in FJP was conducted.Experiments were designed for FJP two kinds of materials corresponding to ductile and brittle materials.They are nickel copper(NiCu)alloy and BK7 optical glass,respectively.In this study,the SOD was varied from 2 to 35 mm.Analysis and discussions were made on its effect on the shape of TIF,material removal rate,and surface topography.It is interesting to note that the TIF shape becomes a Gaussian-like shape with large SOD both on NiCu and BK7,which provides a novel way to optimize the TIF in FJP.The variation of the material removal rate and surface roughness versus SOD on NiCu and BK7 were also determined from the experimental results.Moreover,the surface topography of NiCu and BK7 were characterized from the results measured from the white light interferometer and scan electron microscope.The outcome of the study provides a better understanding of the material removal characteristics and surface generation mechanism in FJP.

关键词： Fluid jet polishing Material removal characteristics Stand-off distance Tool influence function Surface generation Ultra-precision machining

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Mesoplasticity Approach to Studies of the Cutting Mechanism in Ultra-precision Machining

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chinese Journal of Mechanical Engineering 2014年第2期27卷 219-228页

作者： LEE WB Rongbin WANG Hao TO Suet cheung chi fai CHAN Chang Yuen Partner State Key Laboratory of Ultra-precision Machining Technology The Hong Kong Polytechnic University

There have been various theoretical attempts by researchers worldwide to link up different scales of plasticity studies from the nano-, micro- and macro-scale of observation, based on molecular dynamics, crystal plasticity and continuum mechanics. Very few attempts, however, have been reported in ultra-precision machining studies. A mesoplasticity approach advocated by Lee and Yang is adopted by the authors and is successfully applied to studies of the micro-cutting mechanisms in ultra-precision machining. Traditionally, the shear angle in metal cutting, as well as the cutting force variation, can only be determined from cutting tests. In the pioneering work of the authors, the use of mesoplasticity theory enables prediction of the fluctuation of the shear angle and micro-cutting force, shear band formation, chip morphology in diamond turning and size effect in nano-indentation. These findings are verified by experiments. The mesoplasticity formulation opens up a new direction of studies to enable how the plastic behaviour of materials and their constitutive representations in deformation processing, such as machining can be predicted, assessed and deduced from the basic properties of the materials measurable at the microscale.

关键词： ultra-precision machining cutting mechanism mesoplasticity shear angle prediction size effect,micro-cutting force variation high frequency tool-tip vibration

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Time trend and characteristics of prostate cancer diagnosed in Hong Kong(china)in the past two decades

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Asian Journal of Andrology 2019年第1期21卷 104-106页

作者： Ho-fai Wong chi-Hang Yee Jeremy YC Teoh Samson YS Chan Peter KF chiu Ho-Yuen cheung Simon SM Hou chi fai Ng S H.Ho Urology Centre Department of SurgeryThe Chinese University of Hong KongHong KongChina

Dear Editor, Prostate cancer is an important disease worldwide)In 2015 it was the third most common cancer diagnosed in male in Hong Kong (china) and the incidence of prostate cancer has been rising in the past 15 years. Meanwhile,with increasing public awareness,health education, presentation,and detection of prostate cancer maybe changed.Therefore, we would like to review how the epidemiology of prostate cancer in Hong Kong (china)had changed in the past two decades.

关键词： prostate cancer Time trend

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Acupuncture for low back pain:a clinical practice guideline from the Hong Kong taskforce of standardized acupuncture practice

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Journal of Traditional chinese Medicine 2022年第1期42卷 140-147页

作者： CHEN Haiyong YEUNG Wing-fai YANG Mingxiao MU Jinglan ZIEA Tat-chi NG Bacon Fung-Leung LAO Lixing School of chinese Medicine University of Hong KongHong Kong SARChina School of Nursing Hong Kong Polytechnic UniversityHong Kong SARChina Bendheim Integrative Medicine Center Memorial Sloan Kettering Cancer Center1429 First AvenueNew York 10021USA Department of Anesthesiology Nanjing Drum Tower HospitalNanjing University Medical SchoolNanjing210008China chinese Medicine Department Hong Kong Hospital AuthorityHong Kong SARChina Virginia University of Integrative Medicine FairfaxVA 22031USA

OBJECTIVE:To develop a clinical practice guideline to guide the treatment of low back pain by acupuncture.METHODS:An integrative approach of systematic review of literature,clinical evidence classification,expert opinion surveying,and consensus establishing via a Delphi program was utilized during the developing process.Both evidence-based practice standards and the personalized features of acupuncture were taken into considerations.RESULTS:Based on clinical evidence and expert opinions,we developed a clinical practice guideline for the treatment of low back pain with acupuncture.These recommendations have a wide coverage spanning from Western Medicine diagnosis and Traditional chinese Medicine syndrome differentiation,to acupuncture treatment procedures,as well as post treatment care for rehabilitation and follow-ups.The recommendations for acupuncture practice included treatment principles,therapeutic regimens,and operational procedures.The levels of evidence and strength of recommendation were rated for each procedure of practice.CONCLUSION:A clinical practice guideline for acupuncture treating low back pain was developed based on contemporary clinical evidence and experts'consensus to provide best currently agreeable practice guideline for domestic and international stakeholders.

关键词： acupuncture low back pain diagnosis syndrome differentiation rehabilitation practice guideline

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Risk of cardiovascular thrombotic events after surgical castration versus gonadotropin-releasing hormone agonists in chinese men with prostate cancer

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Asian Journal of Andrology 2015年第3期17卷 493-496页

作者： Jeremy YC Teoh Samson YS Chan Peter KF chiu Darren MC Poon Ho-Yuen cheung Simon SM Hou chi-fai Ng Department of Surgery Division of Urology Prince of Wales Hospital The Chinese University of Hong Kong Shatin Hong Kong China Department of Clinical Oncology Prince of Wales Hospital The Chinese University of Hong Kong Shatin Hong Kong China Department of Surgery Division of Urology North District Hospital Hong Kong China

We investigated the cardiovascular thrombotic risk after surgical castration （SC） versus genadotmpin-releasing hormone agonists （GnRHa） in chinese men with prostate cancer. All chinese prostate cancer patients who were treated with SC or GnRHa from year 2000 to 2009 were reviewed and compared. The primary outcome was any new-onset of cardiovascular thrombotic events after SC or GnRHa, which was defined as any event of acute myocardial infarction or ischemic stroke. The risk of new-onset cardiovascular thrombotic event was compared between the SC group and the GnRHa group using Kaplan-Meier method. Multivariate Cox regression analysis was performed to adjust for other potential confounding factors. A total of 684 chinese patients was included in our study, including 387 patients in the SC group and 297 patients in the GnRHa group. The mean age in the SC group （75.3 ~ 7.5 years） was significantly higher than the GnRHa group （71.8 ~ 8.3 years）（P 〈 0.001）. There was increased risk of new cardiovascular thrombotic events in the SC group when compared to the GnRHa group upon Kaplan-Meier analysis （P= 0.014）. Upon multivariate Cox regression analysis, age （hazard ratio [HR] 1.072, 95% confidence interval [CI] 1.04-1.11, P 〈 0.001）, hyperlipidemia （HR 2.455, 95% Cl 1.53-3.93, P 〈 0.001）, and SC （HR 1.648, 95% CI 1.05-2.59, P = 0.031） were significant risk factors of cardiovascular thrombotic events. In conclusion, SC was associated with increased risk of cardiovascular thrombotic events when compared to GnRHa. This is an important aspect to consider while deciding on the method of androgen deprivation therapy, especially in elderly men with known history of hyperlipidemia.

关键词： androgen deprivation therapy chinese population cardiovascular events myocardial infarction prostate cancer stroke

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