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森林对减轻空气污染的作用

林业与环境科学 1988年第5期 39-43+19页

作者： t.c.pokhriyal B.K.Subba Rao 陈定如

森林的水土保持作用已被恰当承认。本文按新的观点,即从减轻空气污染方面考察了森林的作用,同时提出一汾耐污染的树种名录。森林是一个具有生命的复杂群居结构的生物群落。它在水土保持方面起着决定性的作用。它们通过蒸腾作用过程,从... 详细信息

森林的水土保持作用已被恰当承认。本文按新的观点,即从减轻空气污染方面考察了森林的作用,同时提出一汾耐污染的树种名录。森林是一个具有生命的复杂群居结构的生物群落。它在水土保持方面起着决定性的作用。它们通过蒸腾作用过程,从地上提升水分并释放到大气中去,由于大气水分的凝聚作用而产生雨,并如此循环不断。在生态系统中,在低量污染的情况下,生态系统的植被和土壤,起着降低空气污染的作用。在中度污染时,个别树种或特定树种的单株林木会产生养分效应,削弱新陈代谢,易受昆虫感染或出现病理现象,或直接诱发病害。但是,当污染程度高时,就会导致特定树种的严重病态或死亡。洁净的空气对于任何生物体的生存是不可缺少的。地球大气层是气体、水蒸气、固体微粒和液态微滴的混合物。空气污染的定义是指在大气层里的固体、液体和气体物质的浓度足以伤害人类和动植物的生命或特性。空气的组成在地球各处是不尽相同的。空气污染不仅限于城市,也不仅是由人类的活动而引起。火山爆发,森林火灾,大风所刮起的灰尘、花粉和其它悬浮微粒以及诸如细菌和病毒等另一些活微粒,都能污染空气。近三亿 t 空气污染物质散发到空气中去,这大大超过自然系统安全吸收的水平。当人类学会用火时空气污染就开始了。但大规模的空气污染是与近代工业的发展相关的,此外,就产生污染物的活动性质来说,散发到空气中去的都是在人口稠密的地区。因此,其影响即使在全球规模上是小的,但对局部则可能是严重的。据估计,由于大量二氧化碳加入到大气层里,使地球平均温度提高6℃,这可能会造成地球过去7000万年从未经历过的气候情况。即使实际增加的温度较预期的小,但也足以溶化大量极地冰和提高海平面5m。同样,同温层的臭氧能有效地阻挡大量从各方面传到地球表面的有害的太阳紫外辐射线。目前的计算表明,臭氧层的16.5％将会由于人类制造化学药品而消失。毁灭臭氧的半数(近8％)将发生于今后30年内(Khoshoo 和 Ahmad,1981)。工业和都市社团经常散布对周围人类和其它活生物体有害的污染物质。这些污染物质包括放射性尘埃、盐雾、除草剂和农药、大气微粒、烟尘、矿石冶炼、煤的燃烧、制砖、制陶瓷、制水泥、制玻璃、制磷肥、酸物质液滴、煤气和某些时候的土壤微粒。这些物质对一切生物都可以单独起刺激作用,或者它们可能联合起来,对环境起更为有害的不利作用。最近苏联的切尔诺贝尔核电站的火灾并随之而发生的放射性泄漏,对发达国家和发展中国家来说,是一个突出的实例和警告信号。

关键词：空气污染污染物质大气层流体层人工林绿化带气态污染物酸雨酸性降水降雨大气微粒气溶胶森林

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森林在缓和空气污染方面的作用

西部林业科学 1987年第2期 70-75页

作者： t.c.pokhriyal B.K.Subba Rao 曾龄英印度台拉登林学院和林业研究所印度台拉登林学院和林业研究所

引言森林是一个具有正运转着的生物群体复杂“社会”机构的生物群落。树木在保持水土方面可发挥决定性的作用。它们从土地吸收水分,并通过蒸腾压把水释放到大气中,由于大气中水汽的冷凝再以降水形式回归大地,这种作用持续地循环着。在... 详细信息

引言森林是一个具有正运转着的生物群体复杂“社会”机构的生物群落。树木在保持水土方面可发挥决定性的作用。它们从土地吸收水分,并通过蒸腾压把水释放到大气中,由于大气中水汽的冷凝再以降水形式回归大地,这种作用持续地循环着。在生态系标准上,低剂量污染条件下,生态系内的植被和土壤有明显减弱空气污染的功能。当受到中等程度污染剂量时,个别树种或特定树种的个别成员可能会敏感,由于营养恶化、新陈代谢减弱,易遭受害虫或病害的侵袭,或者

关键词：空气污染生态系绿化带二氧化氮人工林北方邦印度酸雨酸性降水降雨气体污染植物光合作用森林木本植物缓和

Effects of layer interactions on instantaneous stability of finite Stokes flows

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 69-84页

作者： chen ZHAO Zhenli cHEN c.t.MUtASA Dong LI School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

the stability analysis of a finite Stokes layer is of practical importance in flow control. In the present work, the instantaneous stability of a finite Stokes layer with layer interactions is studied via a linear stability analysis of the frozen phases of the base flow. the oscillations of two plates can have different velocity amplitudes, initial phases, and frequencies. the effects of the Stokes-layer interactions on the stability when two plates oscillate synchronously are analyzed. the growth rates of two most unstable modes when δ t equal, and δ = δ*/h*, where δ*and h*are the Stokes-layer thickness and the half height of the channel, respectively. However, their vorticities are different. the vorticity of the most unstable mode is symmetric, while the other is asymmetric. the Stokes-layer interactions have a destabilizing effect on the most unstable mode when δ tabilizing effect when δ > 0.68. However, the interactions always have a stabilizing effect on the other unstable mode. It is explained that one of the two unstable modes has much higher dissipation than the other one when the Stokes-layer interactions are strong. We also find that the stability of the Stokes layer is closely related to the inflectional points of the base-flow velocity profile. the effects of inconsistent velocity-amplitude, initial phase, and frequency of the oscillations on the stability are analyzed. the energy of the most unstable eigenvector is mainly distributed near the plate of higher velocity amplitude or higher oscillation frequency. the effects of the initial phase difference are complicated because the base-flow velocity is extremely sensitive to the initial phase.

关键词： finite Stokes layer instantaneous stability Stokes-layer interaction asynchronous oscillation

Near resonance vibration isolation on a levered-dual response(LEDAR)coulomb-damped system by differential preloads/offsets in linear springs

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1033-1050页

作者： t.I.tOLUWALOJU c.K.tHEIN D.HALIM Department of Mechanical Materials and Manufacturing EngineeringUniversity of Nottingham Ningbo ChinaNingbo 315100Zhejiang ProvinceChina Nottingham Ningbo china Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo 315048Zhejiang ProvinceChina

the levered-dual response(LEDAR)coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear *** takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration *** isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without *** compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the potential *** isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate *** observed near resonant isolation thus makes the LEDAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simultaneous harvesterisolation functions and passive functions at extreme frequencies.

关键词： lever ratio coulomb damping preload tension/compression isolation band/depth offset potential

Efficient guiding and focusing of intense laser pulse using periodic thin slits

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Matter and Radiation at Extremes 2024年第4期9卷 29-39页

作者： L.Xu t.W.Huang K.Jiang c.N.Wu H.Peng P.c.hen R.Li H.B.Zhuo c.t.Zhou Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material technology Center for Intense Laser ApplicationTechnologyand College of Engineering PhysicsShenzhen Technology UniversityShenzhen 518118People’s Republic of China

Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle ***,we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser *** fundamental physics of intense laser interaction with thin slits is studied,and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing *** addition,the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional *** results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications.

关键词： laser pulse intense

HI in High Gas-phase Metallicity Dwarf Galaxy WISEA J230615.06+143927.9

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Research in Astronomy and Astrophysics 2024年第1期24卷 292-299页

作者： Yan Guo c.Sengupta t.c.Scott P.Lagos Y.Luo Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China Institute of Astrophysics and Space Sciences(IA Porto) Rua das Estrelas4150-762PortoPortugal

We present resolved Giant Metrewave Radio telescope H I observations of the high gas-phase metallicity dwarf galaxy WISEA J230615.06+143927.9(z = 0.005)(hereafter J2306) and investigate whether it could be a tidal Dwarf Galaxy(tDG) candidate. tDGs are observed to have higher metallicities than normal dwarfs. J2306 has an unusual combination of a blue g-r color of 0.23 mag, irregular optical morphology and high-metallicity(12 +log(O/H) = 8.68 ± 0.14), making it an interesting galaxy to study in more detail. We find J2306 to be an H I rich galaxy with a large extended, unperturbed rotating H I disk. Using our H I data we estimated its dynamical mass and found the galaxy to be dark matter(DM) dominated within its H I radius. the quantity of DM, inferred from its dynamical mass, appears to rule out J2306 as an evolved tDG. A wide area environment search reveals J2306 to be isolated from any larger galaxies which could have been the source of its high gas metallicity. Additionally, the H I morphology and kinematics of the galaxy show no indication of a recent merger to explain the *** detailed optical spectroscopic observations of J2306 might provide an answer to how a seemingly ordinary irregular dwarf galaxy achieved such a high level of metal enrichment.

关键词： galaxies:abundances galaxies:dwarf galaxies:irregular radio lines:galaxies radio lines:ISM

Radiative decays D*(s)→ D(s)γ in covariant confined quark model

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chinese Physics c 2024年第2期48卷 45-56页

作者： c.t.tran M.A.Ivanov P.Santorelli Q.c.Vo Department of Physics HCMC University of Technology and EducationVo Van Ngan 1700000 Ho Chi Minh CityVietnam Bogoliubov Laboratory of theoretical Physics Joint Institute for Nuclear Research141980 DubnaRussia Dipartimento di Fisica"E.Pancini" Universitàdi Napoli Federico ⅡComplesso Universitario di Monte S.AngeloVia CintiaEdificio 680126 NapoliItaly Istituto Nazionale di Fisica Nucleare Sezione di Napoli80126 NapoliItaly University of Science 700000 Ho Chi Minh CityVietnam

Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢ*** radiative couplings gD*Dγencoding nonperturbative QcD effects are calculated in the framework of the covariant confined quark model developed by *** compare our results with other theoretical studies and experimental *** couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).the most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QcD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QcD sum rules.

关键词： covariant quark model radiative decay charmed meson

Finite barrier bound state

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Light(Science & Applications) 2024年第4期13卷 664-671页

作者： tao Liu Kai Bai Yicheng Zhang Duanduan Wan Yun Lai c.t.chan Meng Xiao Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education and School of Physics and technology Wuhan University430072 WuhanChina. National Laboratory of Solid State Microstructures School of Physicsand Collaborative Innovation Center of Advanced MicrostructuresNanjing University210093 NanjingChina. Department of Physics The Hong Kong University of Science and TechnologyClear Water BayKowloon999077Hong KongChina. Wuhan Institute of Quantum technology 430206 WuhanChina

A boundary mode localized on one side of a finite-size lattice can tunnel to the opposite side which results in unwanted *** wisdom tells that the tunneling probability decays exponentially with the size of the system which thus requires many lattice sites before eventually becoming negligibly *** we show that the tunneling probability for some boundary modes can apparently vanish at specific ***,similar to bound states in the continuum,a boundary mode can be completely trapped within very few lattice sites where the bulk bandgap is not even *** intriguingly,the number of trapped states equals the number of lattice sites along the normal direction of the *** provide two configurations and validate the existence of this peculiar finite barrier-bound state experimentally in a dielectric photonic crystal at microwave *** work offers extreme flexibility in tuning the coupling between localized states and channels as well as a new mechanism that facilitates unprecedented manipulation of light.

关键词： boundary state eventually

thermoluminescence characterization of natural and synthetic irradiated ce-monazites

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Journal of Rare Earths 2024年第4期42卷 643-650页

作者： V.correcher c.Boronat J.Garcia-Guinea J.F.Benavente t.Rivera-Montalvo cIEMAt Av.Complutense 4028040MadridSpain MNcN-cSIc J.Gutierrez Abascal 228006MadridSpain Instituto Politécnico Nacional CICATA-IPNAv.Legaria 694Mexico City11500Mexico

the thermoluminescence(tL)emission of synthetic and natural ce-monazites was characterized here to determine the potential application in the identification of microscopic defects from a qualitative point of view trying to link each tL peak to a chemical-physical *** kinetic parameters that lead the luminescence processes were calculated by means of variable heating rate and computing glow curve deconvolution methods and allow identifying three groups of components at~90,130 and 290℃(for the mineral sample)and~90,170,220,270 and 320℃(for the synthetic cePO_(4):Nd_(0.20),La_(0.25)).the main differences appreciated in these complex tL curves are mainly due to(i)the content of impurities(natural sample contains lanthanides as well as U 0.60%and th 5.22%)and(ii)the degree of crystallinity of the samples which is directly related to the type of impurities(synthetic monazite relies only on Nd and La).the behavior of the dose response in the range of 1-8 Gy is similar for both samples;the tL intensity increases linearly as the dose increases without changes in the position of the maxima,denoting first-order kinetic luminescence *** peak could be mostly associated with structural defects(i.e.,phase transitions),chemical reactions(i.e.,ce3+?ce4+redox reaction,dehydration or dehydroxylation processes)or intrinsic defects(i.e.,Frenkel defects,ODcs or NBOHcs).

关键词： thermoluminescence Kineticparameters Phosphate ce-monazite Defects Rare earths