检索结果-南通市图书馆

Velocity variation of internal shock waves in gamma ray bursts: Observational properties

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2006年第4期49卷 505-512页

作者： poon Helen Astronomy Department Beijing Normal University

The work uses the data in the TTS mode of BATSE to analyze the time lags and pulse widths of GRB960113 and GRB960722 in high as well as low energy bands. The results show that their time lags increase monotonously. This phenomenon can reasonably be interpreted with the model of internal shock waves of γ-ray bursts (GRB). Perhaps we obtain the direct observational evidence for the fireball model of GRBs for the first time.

关键词： GRB, time lag, shock wave.

Quality Control of Recycled Aggregates Derived from Construction and Demolition Wastes

在线全文

学校读者我要写书评

暂无评论

四川大学学报（工程科学版） 2009年第3期41卷 248-257页

作者： poon Chi-sun KOU Shi-cong Dept. of Civil and Structural Engineering the Hong Kong Polytechnic Univ. Hung Horn Kowloon Hong Kong

In 2007,over 24 million tons of Construction and Demolition(C&D) wastes were generated in Hong *** the local landfills will be saturated in about 6 years,it is important to find a viable way to reuse these waste materials as to alleviate the demand on public fill *** order to tackle the problem,the Hong Kong government has set up a temporary recycling facility in Hong Kong in 2002 for producing different sizes of recycled aggregate for use in various construction *** Hong Kong Polytechnic University has been studying the feasible use of recycled aggregates in Hong Kong for a number of years.A substantial amount of experimental results on the properties of recycled aggregates and the effect of recycled aggregates on the properties of concrete and other construction products(*** blocks and granular sub-base) has been *** this paper,the experience of Hong Kong in using recycled aggregates are summarized and a set of quality control guidelines proposed for governing the use of recycled aggregates in Hong Kong is *** experience and guidelines may also be useful for the recycling of waste materials derived from the recent Sichuan earthquake in China.

关键词：建筑物工程质量抗震设计建筑结构

Compressive Strength, Pore Size Distribution and Chloride-ion Penetration of Recycled Aggregate Concrete Incorporating Class-F Fly Ash

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2006年第4期21卷 130-136页

作者：寇世聪 C S poon Department of Civil and Structural Engineering The Hong Kong Polytechnic University Hung HomKowloon Hong Kong

The effects of fly ash on the compressive strength, pore size distribution and chloride-ion penetration of recycled aggregate concrete were investigated. Two series of concrete mb：tures were prepared. The concrete mixtures in series I had a water-to-binder ratio and a cement content of 0.55 and 410 kg/ m^3 , respectively. The concrete rnixtures in series II had a water-to-binder ratio and a cement content of 0.45 and 400 kg/ ml respectively. Recycled aggregate was ased as 20% , 50% , and 100% replacements of natural coarse aggregate in the concrete mixtures in both series. In cutdition, fly ash was used as 0% , 25% and 35% by weight replacements of cement. The results show that the compressive strengths of the concrete decreased as the recycled aggregate and the fly ash contents increased. The total porosity and average porosity diameter of the concrete increased us the recycled aggregate content increased. Furtherrruore , an increase in the recycled aggregate content decreased the resistance to chloride ion penetration. Nevertheless, the replacement of cement by 25% fly ush improved the resistance to chloride ion penetration and pore diameters and reduced the total porosity of the recycled aggregate concrete.

关键词： durability properties recycled aggregate concrete fly ash

Recent studies on mechanical properties of recycled aggregate concrete in China-A review

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2012年第6期55卷 1463-1480页

作者： XIAO JianZhuang LI WenGui poon ChiSun Department of Building Engineering Tongji UniversityShanghai 200092China Department of Civil and Structural Engineering Hong Kong Polytechnic UniversityHong KongChina Committee of Recycled Aggregate Concrete Civil Engineering SocietyShanghai 200092China

Numerous experimental and theoretical studies on recycled aggregate concrete have been carried out in China in the past 10 *** paper provides a comprehensive review of the related findings of research on the mechanical properties of RAC in *** influences of the RCA on the strength and deformation characteristics of concrete,the statistical characteristics for the strength of RAC,fracture energy,stress-strain relationships under uniaxial compression,uniaxial tension as well as pure shear,and the residual strength of RAC after exposure to high temperatures,the bond between RAC and different kinds of steel rebar were also ***,some recent studies on the numerical simulation of the failure mechanism for RAC at the meso-structure level were discussed.

关键词： construction and demolition (C&D) wastes recycled coarse aggregate (RCA) recycled aggregate concrete (RAC) me-chanical property test numerical simulation

Artificial intelligence in gastroenterology:where are we heading?

在线全文

学校读者我要写书评

暂无评论

Frontiers of Medicine 2020年第4期14卷 511-517页

作者： Joseph JY Sung Nicholas CH poon Institute of Digestive Disease Faculty of MedicineThe Chinese University of Hong KongHong KongChina Big Data Decision Analytic Cancer The Chinese University of Hong KongHong KongChina

Artificial intelligence(AI)is coming to medicine in a big *** making diagnosis in various medical conditions,following the latest advancements in scientific literature,suggesting appropriate therapies,to predicting prognosis and outcome of diseases and conditions,AI is offering unprecedented possibilities to improve care for *** is a field that AI can make a significant *** is partly because the diagnosis of gastrointestinal conditions relies a lot on image-based investigations and procedures(endoscopy and radiology).AI-assisted image analysis can make accurate assessment and provide more information than conventional *** integration of genomic,epigenetic,and metagenomic data may offer new classifications of gastrointestinal cancers and suggest optimal personalized *** managing relapsing and remitting diseases such as inflammatory bowel disease,irritable bowel syndrome,and peptic ulcer bleeding,convoluted neural network may formulate models to predict disease outcome,enhancing treatment *** and surgical robots can also assist surgeons in conducting gastrointestinal *** the advancement and new opportunities are exciting,the responsibility and liability issues of AI-assisted diagnosis and management need much deliberations.

关键词： artificial intelligence endoscopy robotics gastrointestinal diseases

Anisotropic edge enhancement in optical scanning holography with spiral phase filtering

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2016年第1期14卷 21-25页

作者： Kelly K. Dobson 贾伟 Ting-Chung poon Bradley Department of Electrical and Computer Engineering Virginia TechBlacksburgVA 24061USA Lab of Information Optics and Optoelectronic Technology Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China

Anisotropic edge enhancement is simulated using a spiral phase plate （SPP） in optical scanning holography （OSH）. We propose to use a delta function and an SPP as the pupil functions to realize anisotropic edge enhancement. The interference of these two pupils is used to two-dimensionally scan an object to record its edge-only information. This is done in three ways： first, by shifting the SPP, second, by using two offset SPPs of same charge, and finally, by using two oppositely charged SPPs. Our computer simulations show the capability of selectively enhancing the edges of a given obiect.

关键词： Delta functions Electron holography Holography Scanning Surface plasmon resonance

Model investigation of the low-carbon MgO-treated soil foundation based on CO_(2) overall carbonation

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2023年第11期15卷 2901-2916页

作者： Guanghua Cai Songyu Liu Yuqing Zhong Chisun poon Jiangshan Li School of Civil Engineering Nanjing Forestry UniversityNanjing210037China Institute of Geotechnical Engineering School of TransportationSoutheast UniversityNanjing211189China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong999077China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

The overall carbonation of MgO-admixed soil provides not only an efficient and environmentally friendly technique for improving soft ground but also a permanently safe solution for CO_(2) *** evaluate the carbon sequestration potential and promote the carbonation application in soil improvement,a laboratory-scale model investigation is designed under pressurized carbonation considering the influences of MgO dosage and CO_(2) ventilation mode(way).The temperature,dynamic resilience modulus,and dynamic cone penetration(DCP)were tested to assess the carbonation treatment *** physical,strength,and microscopic tests were also undertaken to reveal the evolution mechanisms of CO_(2) migration in the MgO-carbonated *** results indicate that the temperature peaks of MgO-treated foundation emerge at w20 h during hydration,but occur at a distance of 0e25 cm from the gas source within 6 h during *** dynamic resilience moduli of the model foundation increase by more than two times after carbonation and the DCP indices reduce *** the distance from the gas inlet increases,the bearing capacity,strength,and carbon sequestration decrease,whereas the moisture content *** to the end ventilation,the middle ventilation produces a higher carbonation degree and a wider carbonation *** cementation and filling of nesquehonite and dypingite/hydromagnesite are verified to be critical factors for carbonation evolution and enhancing mechanical ***,the overall carbonation model is described schematically in three stages of CO_(2) *** outcomes would help to facilitate the practical application of CO_(2) sequestration in soil treatment.

关键词： Model investigation Overall carbonation Reactive MgO Engineering properties Microscopic characteristics

Spreadsheet quality assurance:a literature review

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第2期18卷 61-82页

作者： Pak-Lok poon Man Fai LAU Yuen Tak YU Sau-Fun TANG School of Engineering and Technology Central Queensland UniversityMelbourne 3000Australia Department of Computing Technologies Swinburne University of TechnologyHawthorn 3122Australia Department of Computer Science City University of Hong KongHong Kong SAR 999077China The Royal Victorian Eye and Ear Hospital East Melbourne 3002Australia

Spreadsheets are very common for information processing to support decision making by both professional developers and non-technical end ***,business intelligence and artificial intelligence are increasingly popular in the industry nowadays,where spreadsheets have been used as,or integrated into,intelligent or expert systems in various application ***,it has been repeatedly reported that faults often exist in operational spreadsheets,which could severely compromise the quality of conclusions and decisions based on the *** a view to systematically examining this problem via survey of existing work,we have conducted a comprehensive literature review on the quality issues and related techniques of spreadsheets over a 35.5-year period(from January 1987 to June 2022)for target journals and a 10.5-year period(from January 2012 to June 2022)for target *** other findings,two major ones are:(a)Spreadsheet quality is best addressed throughout the whole spreadsheet life cycle,rather than just focusing on a few specific stages of the life cycle.(b)Relatively more studies focus on spreadsheet testing and debugging(related to fault detection and removal)when compared with spreadsheet specification,modeling,and design(related to development).As prevention is better than cure,more research should be performed on the early stages of the spreadsheet life *** by our comprehensive review,we have identified the major research gaps as well as highlighted key research directions for future work in the area.

关键词： decision support system end-user computing end-user programming Excel spreadsheet

Professional practice in prosramming larse public buildinss in China： A questionnaire survey

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Architectural Research 2013年第2期2卷 222-233页

作者： Ying Denga S.W. poon Department of Civil Engineering The University of Hong Kong Hong Kong China Department of Real Estate and Construction The University of Hong Kong Hong Kong China

China＇s large public buildings （LPBs） often become problematic after on｜y a few years＇ operation, leading to shortened building lifespans. Lacking architectural programming was identified by the industry regulators as a contributing factor to this. Despite a policy shift on the government side since 2007, little evaluation of the actual situation has been made. To raise awareness and attention to this pressing issue from the building industry, its regulators and the general public, a questionnaire survey focusing on the top-tier sector of professional practice in programming LPBs was carried out in Shanghai, China in 2009. The objectives were to evaluate current trends and pressing issues, identify major challenges and opportunities, and make recommendations for improvement. This paper presents a six-part analysis of the survey＇s findings from 57 professionals and clients who shared their hands-on experience on various programming issues and provided first-hand data of 90 LPBs developed in the 2000s. This pioneering study revealed significant gaps between the real and best practices as well as the mentat reluctance and skill mismatch in delivering quality programming services. Given the persisting nature of identified problems, more research work should be done to catatyze a paradigmatic shift amon industry players.

关键词： Architectural programming The early stages Large public building(LPB) Questionnaire surveyChina