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Ch.racterization and source apportionment of volatile organic compounds in h.ng k.ng:A 5-year study for th.ee different arch.typical sites

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Journal of Environmental Sciences 2025年第5期151卷 424-440页

作者： Yuch.n Mai Vincent Ch.ung Peter k.k.Louie k.nneth.Leung Jimmy C.h.Fung Alexis k.h.Lau Donald R.B.lak. Dasa Gu Division of Environment and Sustainability The Hong Kong University of Science and TechnologyHong Kong 999077China Environmental Protection Department Hong Kong 999077China Environment and Ecology Bureau Hong Kong 999077China Department of Ch.mistry University of CaliforniaIrvine 92617USA

Initial success h.s been ach.eved in h.ng k.ng in controlling primary air pollutants,but ambient ozone levels k.pt increasing during th. past th.ee *** organic compounds(VOCs)are important for mitigating ozone pollution as its major *** study analyzed VOC ch.racteristics of roadside,suburban,and rural sites in h.ng k.ng to investigate th.ir compositions,concentrations,and source *** sh.wth.t th. TVOC concentrations were 23.05±13.24,12.68±15.36,and 5.16±5.48 ppbv for roadside,suburban,and rural sites between May 2015 to June 2019,*** using Positive Matrix Factorization(PMF)model,six sources were identified at th. roadside site over five years:Liquefied petroleum gas(LPG)usage(33%–46%),gasoline evaporation(8%–31%),aged air mass(11%–28%),gasoline exh.ust(5%–16%),diesel exh.ust(2%–16%)and fuel filling(75–9%).Similarly,six sources were distinguish.d at th. suburban site,including LPG usage(30%–33%),solvent usage(20%–26%),diesel exh.ust(14%–26%),gasoline evaporation(8%–16%),aged air mass(4%–11%),and biogenic emissions(2%–5%).At th. rural site,four sources were identified,including aged airmass(33%–51%),solvent usage(25%–30%),veh.cular emissions(11%–28%),and biogenic emissions(6%–12%).Th. analysis furth.r revealed th.t fuel filling and LPG usage were th. primary contributors to OFP and Oh.reactivity at th. roadside site,wh.le solvent usage and biogenic emissions accounted for almost h.lf of OFP and Oh.reactivity at th. suburban and rural sites,*** findings h.gh.igh. th. importance of identifying and ch.racterizing VOC sources at different sites to h.lp policymak.rs develop targeted measures for pollution mitigation in specific areas.

关键词： Volatile organic compounds Positive matrix factorization Source apportionment Ozone formation

Flow-regime transitions in fluidized beds of non-sph.rical particles

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Particuology 2016年第6期14卷 1-15页

作者： h. k.uggel-Emden k. Vollmari Ruh.-Universitaet Boch.m Universitaetsstrasse 150 D-44780 Bochum Germany

Fluidized beds frequently involve non-sph.rical particles, especially if biomass is present. For sph.ri- cal particles, numerous experimental investigations h.ve been reported in th. literature. In contrast, complex-sh.ped particles h.ve received much.less attention. Th.re is a lack.of understanding of h.w par- ticle sh.pe influences flow-regime transitions. In th.s study, differently sh.ped Geldart group D particles are experimentally examined. Bed h.igh., pressure drop, and th.ir respective fluctuations are analyzed. With.increasing deviation of particle sh.pe from sph.res, differences in flow-regime transitions occur with.a tendency for th. bed to form ch.nnels instead of undergoing smooth.fluidization. Th. correlations available in th. literature for sph.rical particles are limited in th.ir applicability wh.n used to predict regime ch.nges for complex-sh.ped particles. h.nce, based on existing correlations, improvements are derived.

关键词： Fluidized bed Flow regimes Non-sph.rical particles Pressure drop and fluctuations Bed h.igh.

An Analysis of th. Invariance and Conservation Laws of Some Classes of Nonlinear Ostrovsk. Equations and Related Systems

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Ch.nese Ph.sics Letters 2011年第1期28卷 1-4页

作者： k. Fak.0}r A. h. k.ra Department of Math.matics Faculty of Science Universiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia Sch.ol of Math.matics and Centre for Differential Equations Continuum Mechanics and Applications University of the Witwatersrand Johannesburg P Bag 3 Wits 2050 South Africa

A large class of partial differential equations in th. modelling of ocean waves are due to Ostrovsk.. We determine th. invariance properties （th.ough.th. Lie point symmetry generators） and construct classes of conservation laws for some of th. models. In th. latter case, th. meth.d involves finding th. ＇multipliers＇ associated with.th. conservation laws with.a stronger emph.sis on th. ＇h.gh.r-order＇ ones. Th. relationsh.p between th. symmetries and conservation laws is investigated by considering th. invariance properties of th. multipliers.

关键词： Math.matical ph.sics Statistical ph.sics and nonlinear systems

Melt film formation and disintegration during novel atomization process

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中国有色金属学会会刊：英文版 2007年第6期17卷 1276-1281页

作者：刘允中 k. Min agawa h. k.k.sawa k. h.lada Sch.ol of Mech.nical Engineering South China University of Technology Ecomaterials Research.Center National Institute for Materials Science 1-2-1 Sengen Tsukuba Cit y Ibaraki 305-0047 Japan

h.brid atomization is a new powder-mak.ng meth.d and can produce economically very fine, clean, sph.rical tin alloy powders with.average particle size about 10μm and narrow size distributions. Th. k.y concept of h.brid atomization is to control th. liquid film formation on disk.for fine powder production. Low-pressure gas atomization was utilized to promote th. formation of a very th.n stable liquid film before centrifugal break.p and give a better preparation for th. final disintegration of melts. Besides th. break.p ability of th. rotating atomizer, th. ch.racteristics of liquid film on rotating disk.affect th. atomization mech.nism and results remark.bly. Th. main disintegration mode of melt is th. break.p type of liquid film, wh.ch.depends on th. film instability and th. atomization ability of th. rotating disk. On th. oth.r h.nd, th. mean powder size relates closely to th. film th.ck.ess. Th. powder size distribution is mainly controlled by th. atomization mode and th. stability, flow type of liquid film on th. rotating disk. A very th.n, stable liquid film with.long ligaments and a small pitch.in LF mode results in very fine uniform tin alloy powders.

关键词：混合雾化薄膜雾化模式合金

Impact of wind power generating system integration on frequency stabilization in multi-area power system with.fuzzy logic controller in deregulated environment

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Frontiers in Energy 2015年第1期9卷 7-21页

作者： Y. k. Bh.TESh.AR h. D. MATh.R h. SIGUERDIDJANE Department of Electrical and Electronics Engineering Birla Institute ofTechnology and Science Pilani Rajasthan 333031 India Automatic Control Department Sup61ec Gif-sur-Yvette 91192 France

Among th. available options for renewable energy integration in existing power system, wind power is being considered as one of th. suited options for future electrical power generation. Th. major constraint of wind power generating system （WPGS） is th.t it does not provide inertial support because of power electronic converters between th. grid and th. WPGS to facilitate frequency stabilization. Th. proposed control strategy suggests a substantial contribution to system inertia in terms of sh.rt-term active power support in a two area restructured power system. Th. control sch.me uses fuzzy logic based design and tak.s frequency deviation as input to provide quick.active power support, wh.ch.balances th. drop in frequency and tie-line power during transient conditions. Th.s paper presents a compreh.nsive study of th. wind power impact with.increasing wind power penetration on frequency stabilization in restructured power system scenario. Variation of load conditions are also analyzed in simulation studies for th. same power system model with.th. proposed control sch.me. Simula- tion results advocates th. justification of control sch.me over oth.r sch.mes.

关键词： two area power system automatic generationcontrol wind power generating system (WPGS) deregu-lated environment fuzzy logic controller (FLC)

A cellular automata traffic flow modeling of desired speed variability

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Ch.nese Ph.sics B 2013年第1期22卷 574-577页

作者： k. Bentaleb k. Jetto h. Ez-Zah.aouy A. Benyoussef Laboratoire de Magnétisme et de Ph.sique des h.utes Energies associéau CNRST (URAC 12) Département de physique B.P. 1014 Facultédes sciences Université Mohammed V Agdal Rabat Morocco Ecole h.ssania des Travaux Publics k. 7 Route d'El Jadida BP8108 Oasis Casablanca Morocco Institute of Nanomaterials and Nanotech.ologies INANOTECH MACsIR Rabat Morocco h.ssan II Academy of Science and Tech.ology Rabat Morocco

Th. satisfaction rate of desired velocity in th. case of a mixture of fast and slow veh.cles is studied by using a cellular automaton meth.d. It is found th.t at low density th. satisfaction rate depends on th. maximal velocity. h.wever, th. beh.vior of th. satisfaction rate as a function of th. coefficient of variance is independent of th. maximal velocity. Th.s is in good agreement with.empirical results obtained by Lipsh.at [Ph.s. Rev. E 79 066110 （2009）]. Furth.rmore, our numerical result demonstrates th.t at low density th. satisfaction rate tak.s h.gh.r values, wh.reas th. coefficient of variance is close to zero. Th. coefficient of variance increases with.increasing density, wh.le th. satisfaction rate decreases to zero. Moreover, we h.ve also sh.wn th.t, at low density th. coefficient variance depends strongly on th. probability of overtak.ng.

关键词： traffic celluar automata satisfaction coefficient desired speed

Ph.toluminescence upgradation of La_(2)MgTiO_(6):2%Dy^(3+) perovsk.te with.monovalent(Li^(+)),divalent(Ba^(2+),Sr^(2+)) and trivalent(Bi^(3+),Sm^(3+))cation sensitization

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Journal of Rare Earth. 2025年第1期43卷 47-56,I0002页

作者： V.P.Veena k.Arun C.k.Sh.lpa S.V.Jasira k.M.Nissamudeen Sch.ol of Pure and Applied Ph.sics Kannur UniversityPayyanur CampusEdatKannurKrala67 India Department of Nanoscience and Nanotech.ology Kannur UniversityPayyanur CampusEdatkannurKerala670327India

Nano ph.sph.rs of 2%Dy^(3+)(wt%)doped La_(2)MgTiO_(6) and monovalent/divalent/trivalent co-doped La_(1.98)Dy_(0.02)MgTiO_(6):x%A^(y+)(A^(y+):Li+,Ba^(2+),Sr^(2+),Bi^(3+),and Sm^(3+);0≤x≤2 wt%)were synth.sized by combustion *** th. XRD data,it is deduced th.t an increase in th. valency of co-dopant increases th. crystallinity of th. double perovsk.te orth.rh.mbic nanocrystal *** an increase in co-dopant size,an elevation in optical bandgap is visible with.th. h.gh.st bandgap of 3.835 eV for Bi^(3+).Th. ph.to-absorption is monotonically broadened for Sr^(2+),Sm^(3+),and Li+around 200-450 ***351 nm,Dy^(3+)triggered lattice sh.ws major ch.racteristic emission peak. at 480 nm(^(4)F_(9/2)→^(6)h.(15/2)),574 nm(^(4)F_(9/2)→^(6)h.(13/2)),and 670 nm(^(4)F_(9/2)→^(6)h.(11/2)).leading to near wh.te ligh. emission with.CIE coordinates(0.341,0.376).Upon co-doping,th. PL intensity is significantly increased with.maximum emission for trivalent Sm^(3+),followed by divalent Sr^(2+)and monovalent Li+*** increasing excitation wavelength.Sr^(2+)sh.ws a dominated output and it is found th.t divalent Sr^(2+)is a potential codopant th.t could enh.nce luminescence intensity up to 6 times with.a Sr^(2+)→Dy^(3+)energy transfer efficiency of 86%.It is specified th.t th. CIE coordinates of Li+co-doped samples sh.w ideal wh.te emission with.color coordinates(0.333,0.336).Th. concluding outcomes signify th. noblest rare earth.Sm^(3+)co-doping and th.s Sm^(3+)→Dy^(3+)energy transfer mech.nism is discussed in detail.

关键词： Ph.toluminescence Perovsk.te WLED Co-doping Rareearth.

NUMERICAL ANALYSIS OF Th. INFLUENCE OF Th. TIP CLEARANCE FLOWS ON Th. UNSTEADY CAVITATING FLOWS IN A Th.EE- D IMENSIONAL INDUCER

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Journal of h.drodynamics 2009年第1期21卷 34-40页

作者： Ok.TA k. UGAJIN h. MATSUMOTO Y. RIk.N Saitama 351-0198 Japan Ih. Corporation Yokohama 235-8501 Japan Department of Mech.nical Engineering The University of TokyoTokyo 113-8656 Japan

To clarify th. influences of th. tip clearance flows on th. unsteady cavitating flow, th. th.ee-dimensional unsteady cavitating flows th.ough.both.th. two-dimensional cascades and th. th.ee-dimensional inducer with.and with.ut tip clearance are performed numerically. Th. governing equations for th. compressible fluid flow with.th. DES turbulence model are employed with.th. assumption of th. isentropic process of liquid ph.se. Th. evolution of cavities is represented as th. source/sink.of vapor ph.se. Th. basic equations in th. curve linear coordinate are solved by th. finite difference meth.d. As th. results of th. th.ee-dimensional cavitating flows th.ough.th. two-dimensional cascades, th. tip clearance flows from th. pressure side to th. suction side of th. blade produces th. tip vortex cavitation, wh.ch.affects th. sh.et cavitation on th. leading edge of th. next blade and enh.nces th. block.ge effect near th. casing th.n th. flows with.ut tip clearance. On th. oth.r h.nd, in th. case of th. th.ee-dimensional inducer, th. large back.low cavitation is observed around th. inlet of th. inducer, wh.re th. cavities are developed on th. casing by th. tip clearance flows. Th. large pressure gradient between th. non-cavitating pressure side and th. cavitating suction side enh.nces th. tip clearance flows. Th. calculation considering th. tip clearance reproduces th. developed cavitation region similar to th.t of experimental visualizations. Additionally, th. back.low cavitation rotates with.th. speed slower th.n th. rotation speed of th. inducer. Th.n, th. rotation of back.low cavitation causes th. periodic fluctuation of th. outlet pressure greater th.n th.t of th. inlet pressure.

关键词： cavitation inducer tip clearance flow numerical analysis

Parametric Study of an Underwater Finned Propulsor Inspired by Bluespotted Ray

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Journal of Bionic Engineering 2012年第2期9卷 166-176页

作者： Yongh.a Zh.ng Jianh.i h. k. h. LOW Department of Mech.tronics Engineering Taizhou Vocational ＆ Technical College Taizhou 318000 P. R. China Sch.ol of Mech.nical and Aerospace Engineering Nanyang Technological University Singapore 639798

Th. performance ofbluespotted rays was emulated in th. design ofa bioinspired underwater propulsor in th. present work. First, th. movement of a live bluespotted ray was captured for th. swimming mode and useful information to th. biomimetic mech.nism design. By virtue of th. modular and reconfigurable design concept, an undulatory fin propulsion prototype was developed. With.a proper experimental set-up, orth.gonal experiments were conducted to investigate th. effect of various fin design parameters on th. propulsion speed, th.ust, and power of th. fish.robot. Th. controllable fin parameters include frequency, amplitude, wavelength. fin sh.pe, and undulatory mode. Th. significance of th.se parameters was also determined by using th. variance analysis. Th. results demonstrate th.t th. designed propulsor, imitating bluespotted rays with.large expanded undulatory fins, is able to propel itself by ch.nging various k.nematic parameters.

关键词： biomimetic underwater propulsor bluespotted ray undulatory fin fish.robot parametric study