检索结果-南通市图书馆

Whole pictures of halogenated disinfection byproducts in tap water from China＇s cities

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2015年第1期9卷 121-130页

作者： Yang PAN Xiangru ZHANG Jianping ZHAI State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University Nanjing 210023 China Environmental Engineering Program Department of Civil and Environmental Engineering The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong China

When bromide/iodide is present in source water, hypobromous acid/hypoiodous acid will be formed with addition of chlorine, chloramine, or other disinfectants. Hypobromous acid/hypoiodous acid undergoes reactions with natural organic matter in source water to form numerous brominated/iodinated disinfection byproducts （DBPs）. In this study, tap water samples were collected from eight cities in China. With the aid of electrospray ionization-triple quadrupole mass spectrometry by setting precursor ion scans of m/z 35, m/z 81, and m/z 126.9, whole pictures of polar chlorinated, brominated, and iodinated DBPs in the tap water samples were revealed for the first time. Numerous polar halogenated DBPs were detected, including haloacetic acids, newly identified halogenated phenols, and many new/unknown halogenated compounds. Total organic chlorine, total organic bromine, and total organic iodine were also measured to indicate the total levels of all chlorinated, brominated, and iodinated DBPs in the tap water samples. The total organic chlorine concentrations ranged from 26.8 to 194.0 μg· L 1 as Cl, with an average of 109.2 μg·L-1 as Cl; the total organic bromine concentrations ranged from below detection limit to 113.3 μg·L-1 as Br, with an average of 34.7 μg·L-1 as Br; the total organic iodine concentrations ranged from below detection limit to 16.4 μg· L-1 as I, with an average of 9.1 μg· L-1 as I; the total organic halogen concentrations ranged from 31.3 to 220.4 μg·L-1 as Cl, with an average of 127.2 μg· L- 1 as Cl.

关键词： Disinfection byproducts (DBPs) total organichalogen tap water in China

Association between tropospheric temperature and tropical cyclone peak intensity over the North Pacific and North Atlantic

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2022年第2期15卷 33-38页

作者： Zhenxi Zhang Cong Zhang Wen Zhou College of Energy and Power Engineering Inner Mongolia University of TechnologyHohhotChina School of Energy and Environment City University of Hong KongTat Chee AvenueKowloonHong KongChina

As natural weather disasters,tropical cyclones(TCs)are destructive in proportion to their peak *** study investigates the association of North Atlantic,western North Pacific,and eastern North Pacific TC peak intensities with tropospheric air temperature,respectively,by applying NCEP–NCAR and MERRA reanalysis *** the correlation between TC peak intensity and air temperature and the difference in air temperature between strong and weak TC peak intensity conditions reveal that significant cooling of the tropopause and uppertropospheric warming are accompanied by strengthening TC peak intensity for North Atlantic TCs,suggesting an important effect of upper-tropospheric static stability on TC peak ***,warming in the lower troposphere is associated with strong TC peak intensity for eastern North Pacific TCs,indicating a major effect of lower-tropospheric static stability on TC peak *** peak intensity of western North Pacific TCs is mainly affected by vertical wind shear,not the atmospheric temperature.

关键词： Tropical cyclone Carnot cycle Potential intensity theory

Generic Transformation from Weakly to Strongly Unforgeable Signatures

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2008年第2期23卷 240-252页

作者：黄琼王石李进赵一鸣 Department of Computer Science City University of Hong KongHong KongChina International Research Center for Information Security(IRIS) Information and Communications University( ICU)103-6 Munji-DongYuseong-GuDaejeon305-732Korea Department of Computer Science and Engineering Fudan UniversityShanghaiChina

Current techniques for transforming unforgeable signature schemes （the forged message has never been signed） to strongly unforgeable ones （the forged message could have been signed） require supplementary components to be added onto the original key pairs of the schemes. In addition, some of them can only be applied to a certain type of signature schemes. In this paper, we propose a new generic transformation technique which converts any unforgeable signature scheme into a strongly unforgeable one without modifying any component in the original key pair. This makes our technique especially compatible for practical use. Our technique is based on strong one-time signature schemes. We show that they can be constructed efficiently from any one-time signature scheme that is based on one-way functions. The performance of our technique also compares favorably with that of current ones. Besides, it is shown in this paper that our transformation can further be applied to schemes satisfying only a weak variant of unforgeability without any further modification. Furthermore, our technique can also be used for constructing strongly unforgeable signature schemes in other cryptographic settings which include certificateless signature, identity-based signature, and several others. To the best of our knowledge, similar extent of versatility is not known to be supported by any of those comparable techniques. Finally and of independent interest, we show that our generic transformation technique can be modified to an on-line/off-line signature scheme, which possesses a very efficient signing process.

关键词： signature strong unforgeability weak unforgeability one-time signature

A Model of the Sea-Land Transition of the Mean Wind Profile in the Tropical Cyclone Boundary Layer Considering Climate Changes

在线全文

学校读者我要写书评

暂无评论

International Journal of Disaster Risk Science 2023年第3期14卷 413-427页

作者： Jiayao Wang Tim K.T.Tse Sunwei Li Jimmy CHFung Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHongKong999077China Shenzhen International Graduate School Tsinghua UniversityShenzhen518055China Department of Mathematics The Hong Kong University of Science and TechnologyHongKong 999077China

The tropical cyclone boundary layer(TCBL)connecting the underlying terrain and the upper atmosphere plays a crucial role in the overall dynamics of a tropical cyclone *** tropical cyclones approach the coastline,the wind field inside the TCBL makes a sea-land transition to impact both onshore and offshore *** better understanding of the wind field inside the TCBL in the sea-land transition zone is of great *** this end,a semiempirical model that integrates the sea-land transition model from the Engineering Sciences Data Unit(ESDU),Huang's refined TCBL wind field model,and the climate change scenarios from the Coupled Model Intercomparison Project Phase 6(CMIP6)is used to investigate the influence of climate changes on the sea-land transition of the TCBL wind flow in hong *** specifically,such a semiempirical method is employed in a series of Monte-Carlo simulations to predict the wind profiles inside the TCBL across the coastline of hong kong under the impact of future climate *** wind profiles calculated based on the Monte-Carlo simulation results reveal that,under the influences of the most severe climate change scenario,slightly higher and significantly lower wind speeds are found at altitudes above and below 400 m,respectively,compared to the wind speeds recommended in the hong kong Wind Code of *** findings imply that the wind profile model currently adopted by the hong kong authorities in assessing the safety of low-to high-rise buildings may be unnecessarily over-conservative under the influence of climate *** the other hand,the coded wind loads on super-tall buildings slightly underestimate the typhoon impacts under the severe climate change conditions anticipated for coastal southern China.

关键词： Climate change hong kong Sea-land transition Tropical cyclone boundary layer Wind speed profile

Effect of Earthworm(Pheretimasp.) Density on Revegetation of Lead/zinc Metal Mine Tailings Amended with Soil

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Population,Resources and Environment 2008年第2期6卷 43-48页

作者： Cheng Jiemin Ming H Wong College of Population Resources and Environment Shandong Normal University Jinan Shandong 210014 China Croucher Institute for Environmental Sciences Department of Biology Hong Kong Baptist University Hong Kong China

The objective of this study was to investigate the ef- fects of earthworm density on the availability of nutrients and heavy metals in metal contaminated ***/Zn mine tailings were mixed throughly with a red yellow podzolic soil at the ratio (w/w) of 75:*** (Pheretima sp.) were introduced to the mixture at four different densities,zero,three,six and nine individuals per pot planted with ryegrass (Loliun multiflorum). The results indicated that earthworm activity significantly en- hanced ryegrass shoot ***,as denser earthworm population was introduced,shoot biomass tended to decrease. Earthworm activity significantly increased soil pH and availability of N,P and K in the tailings and soil *** was a general tendency that uptake of Zn by ryegrass increased after earthworm inoculation,although the increase in extractable Zn in tailings and soil mixture was not *** the contrary,there seemed to be a lower uptake of Pb by ryegrass under earthworm inoclation, despite the fact that higher extractable Pb concentrations were *** present project indicated that the improved growth of ryegrass was due to improved nutrient availability and other soil conditions,by inoculation of earthworms at an appropriate *** studies are needed to illustrate the relationship be- tween metal availability and earthworm activity in the field.

关键词： lead zinc nitrogen phosphorus phytostabilization Pb/Zn mine tailings

Martin boundary and exit space on the Sierpinski gasket

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2012年第3期55卷 475-494页

作者： LAU Ka-Sing NGAI Sze-Man Department of Mathematics The Chinese University of Hong Kong Department of Mathematical Sciences Georgia Southern University

We define a new Markov chain on the symbolic space representing the Sierpinski gasket (SG),and show that the corresponding Martin boundary is homeomorphic to the SG while the minimal Martin boundary is the three vertices of the *** addition,the harmonic structure induced by the Markov chain coincides with the canonical one on the *** suggests another approach to consider the existence of Laplacians on those self-similar sets for which the problem is still not settled.

关键词： Martin boundary Markov chain Green function harmonic function fractal Sierpinski gasket

Tribological characteristics of UHMWPE composite and relationship with its compressive behavior

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2004年第Z1期47卷 79-87页

作者： LI Jian, GUO Zhiguang, HUA Meng, QIN Xiangpei & WEN ShizhuWuhan Research Institute of Materials Protection, Wuhan 430030, China Department of Manufacturing Engineering and Engineering Management, City University of hong kong, hong kong, China State Key Laboratory of Tribology, Tsinghua University, Beijing 1000184, China Wuhan Res Inst Mat Protect Wuhan 430030 Peoples R China City Univ hong kong Dept Mfg Engn & Engn Management Hong Kong Hong Kong Peoples R China Tsing Hua Univ State Key Lab Tribol Beijing 1000184 Peoples R China

The triboogical characteristics and the mechanics compress behaviors of pure and composite ultra high molecular weight polyethylene (UHMWPE) were investigated using tribological apparatus and universal materials testing apparatus *** show that there are direct relationships between the sliding friction, wear characteristics, and compression behaviors of UHMWPE composite. The composite of UHMWPE with added copper particles had great improvement in tribological characteristics and mechanics behaviors. Based on the experimental results, a microstructure model of UHMWPE-copper composite is preliminarily proposed.

关键词： UHMWPE, composite tribology, compressive behavior creep.

SIMULATION OF FABRIC DRAPE USING A THIN PLATE ELEMENT WITH FINITE ROTATION

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 1998年第3期14卷 239-247页

作者：陈明祥孙庆平袁铭辉 On leave from Department of Hydroelectric Engineering Wuhan University of Hydraulic and Electric EngineeringWuhan 430072China On leave from Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China Department of Mechanical Engineering The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina

The draping behavior of fabric is simulated by using four node quadrilateral thin plate elements with finite rotation. The finite element formulation is based on the total Lagrangian approach. An exact representation of finite rotation is introduced. The strain energy function accounting for the material symmetry is obtained by the tensor representation theory. To avoid shear locking, the assumed strain technique for transverse shear is adopted. The conjugate gradient method with a proposed line search algorithm is employed to minimize energy and reach the final shape of fabric. The draping behavior of a rectangular piece of fabric over a rectangular table is simulated. (Author abstract) 9 Refs.

关键词： nonlinear finite element cloth draping flexible thin plate finite rotation tensor function representation theory conjugate gradient

Molecular movements of trehalose inside a single network enabling a rapidly-recoverable tough hydrogel

在线全文

学校读者我要写书评

暂无评论

International Journal of Smart and Nano Materials 2022年第4期13卷 575-596页

作者： Xiaowen Huang Jimin Fu Huiyan Tan Yan Miu Mengda Xu Qiuhua Zhao Yujie Xie Shengtong Sun Haimin Yao Lidong Zhang School of Chemistry and Molecular Engineering East China Normal UniversityShanghaiChina Department of Mechanical Engineering the Hong Kong Polytechnic UniversityHong Kong SARChina State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of ChemistryChemical Engineering and BiotechnologyCenter for Advanced Low-dimension MaterialsDonghua UniversityShanghaiChina The hong kong Polytechnic University Shenzhen Research Institute ShenzhenChina

It remains a challenge to achieve rapidly recoverable hydrogels by molecular hydrogen-bonding interaction because of its slow inter-action *** work for the first time reports a trehalose(Tre)-based molecular movement mechanism inside a single network of polyacrylamide(PAM)that accelerates the kinetics of hydrogenbonding interaction,and thereby endows the hydrogel with high toughness and rapid shape and mechanical *** resultant PAM@Tre hydrogel is capable of full shape recovery after 10,000 loading/unloading cycles at a strain of 500%.Even after being stretched at a strain of 2500%,it can recover to its original shape within 10 ***,the molecular movement of trehalose also endows the PAM@Tre hydrogel with fracture energy and toughness as high as~9000 J m^(-2) and~1600 kJ m^(-3),respec-tively,leading to strong resistance to both static and dynamic *** PAM@Tre hydrogel is thus believed to have enormous potentials in protection devices,bionic skin,soft actuator,and stretchable electronics.

关键词： molecular motility highly recoverable tough hydrogels puncture resistance molecular dynamics simulation