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991.
A multipole expansion of the velocity potential is described for two- and three-dimensional wave diffraction and radiation problems. The velocity potential is expressed in terms of a series of multipole potentials. The wave terms and the local disturbance terms are represented by separated multipole potentials. Floating bodies and submerged bodies are treated in the same way. This approach differs from that of some other authors, who considered floating bodies and submerged bodies separately and derived entirely different multipoles. Semi-analytical solutions for a circular cylinder in two-dimensional motions are given. It is found that the local disturbance decays rapidly and steadily. The general application of the multipole expansion to arbitrary geometries is also presented, based on a method coupling multipoles to a boundary integral expression. Numerical results for several floating and submerged cylinders are presented. 相似文献
992.
Wen Shengchang 《海洋学报(英文版)》1988,7(1):1-16
In this part ot the paper theoretical wind-wave spectra nave been derived oy (I) expressing the spectrum in series composed of exponential terms; (2) assuming that the spectrum satisfies a high order linear ordinary differential equation; (3) introducing proper parameters in the spectrum; and (4) making use of some known charateristics of wind-wave spectrum, for instance, the law governing the equilibrium range. The spectrum obtained contains the zero order moment of the spectrum m0, the peak frequency ω0 and the ratio R =ω/ω0 (ω being the mean zero-crossing frequency) as parameters. The shape of the nondimensional spectrum S(ω) = ω0S(ω)/m0(ω=ω/ω0) changes with R and theoretically reduces to a Dirac delta function δ(ω-1) when R = 1. A spectrum of simplified form is given for practical uses, in which R is replaced by a peakness factor P=S(1). 相似文献
993.
The anoxic rates of heat dissipation by mussels (Mytilus edulis) were enhanced after exposure to pentachlorophenol (PCP) and tributyltin (TBT), both known uncouplers of oxidative phosphorylation. The degree of metabolic activation under anoxia was dependent upon the amount of toxicant accumulated in the tissues, but the concentration-response relationship was different to that under aerobic conditions. Biochemical measurements indicated that the anaerobic metabolic pathways were significantly disturbed by PCP and TBT. There was a decline in succinate, an increase in the fumarate: succinate ratio, and an increase in the accumulation of lactate, indicating a shift from succinate to lactate anaerobic pathways. A consequence of organic toxicant exposure was a reduction in anoxic survival time of mussels. 相似文献
994.
Variability in water temperature, salinity and density was investigated based on field measurements near Anzali Port, in the
Southern Caspian Sea in 2008. Seasonal changes of seawater properties were mainly observed through the upper 100 m layer,
while below this layer seasonal variations of the parameters were minor. Vertical structure of the temperature in the southern
coastal waters of the Caspian Sea is characterized by a significant seasonal thermocline between 20–50 m depths with vertical
variation in temperature about 16°C in midsummer (August). Decrease of the thermocline occurs with the general cooling of
the air and sea surface water, and deepening of the mixed layer during late of autumn and winter. Seasonal averages of the
salinity were estimated in a range of 12.27–12.37 PSU. The structure of thermocline and pycnocline indicated agreement between
changes of temperature and density of seawater. Seasonal pycnocline was observed in position of the thermocline layer. 相似文献
995.
The Marine and Coastal Access Act 2009 is now enacted into law. This paper looks at predictions made about new law by one of the authors, Peter Jones, in his paper The Marine Bill: Cornucopia or Pandora's Box [1] and assesses how successful the Act has been in turning aspirations into law. The paper focuses on the following areas: ecosystem protection, stakeholder engagement, marine spatial planning and the provision of a network of highly protected marine reserves, and raises concerns that the ecosystem approach has progressively been dropped in the drafting process of the legislation. Concerns are raised that the new Inshore Fisheries and Conservation Authorities have similar inherent conflicts of interest to those exhibited by Sea Fisheries Committees, which they sought to replace. The effectiveness of marine planning is questioned, as there appear to be inbuilt loopholes for public authorities to avoid complying with the marine plans. The draft marine policy statement (MPS), published in July 2010, includes appropriate environmental safeguards, but the MPS has not yet been formally adopted. The absence of a concrete target for highly protected marine reserves means there is a danger that designations under the Act may have little effect on the ground. In conclusion the Act provides some new mechanisms for marine protection, but arguably does not yet provide a framework for implementing the ecosystem approach and is not an end in itself. 相似文献
996.
This article aims to generate insights into both private governance and partnerships within the shipping industry, but also tries to improve understanding of the complex process of institutionalisation.This is achieved through a case study of the Clean Shipping Project, a public/private partnership that aims to promote sustainability in the shipping industry. A set of enabling and constraining factors are examined that shape the institutionalisation process and determine to what extent the Clean Shipping Project can establish and expand authority as an industry norm.Overall, the Clean Shipping Project cannot yet be considered a full-fledged private governance institution, because of an insufficient level of collaborative advantage mainly due to weak system robustness and unfavourable market characteristics and conditions. However, institutionalisation is an ongoing process and the future outlook for the Clean Shipping Project remains promising. The Clean Shipping Project is certainly a relevant supplement to existing regulations and there is a basic level of commitment and cohesion within the partnership, so it is not unlikely that in the future this initiative may help to uncouple growth in shipping activities from environmental harm. 相似文献
997.
E. A. Mareev V. N. Stasenko A. A. Bulatov S. O. Dement’eva A. A. Evtushenko N. V. Il’in F. A. Kuterin N. N. Slyunyaev M. V. Shatalina 《Izvestiya Atmospheric and Oceanic Physics》2016,52(2):154-164
This review contains the most significant results of Russian studies in the field of atmospheric electricity in 2011–2014. It is part of the Russian National Report on Meteorology and Atmospheric Sciences to the International Association of Meteorology and Atmospheric Sciences (IAMAS). The report was presented and approved at the XXVI General Assembly of the International Union of Geodesy and Geophysics (IUGG).1 The review is followed by a list of the main published works on the studies of atmospheric electricity of Russian scientists in 2011–2014. 相似文献
998.
A. I. Ryabinin S. A. Bobrova L. V. Saltykova E. A. Danilova 《Physical Oceanography》2012,21(5):320-328
We study the space-and-time variations of the delivery of fluxes of 26 elements (Na, K, Rb, Cs, Cu, Ag, Au, Ca, Sr, Ba, Zn,
Cd, Hg, Hf, Ta, As, Sb, Cr, Se, Mo, W, Mn, Br, Fe, Co and Ni) with atmospheric precipitations to the sea surface in the regions
of Sevastopol and the South Coast of Crimea. It is established A series of general regularities of the delivery of the sum
of these elements and their soluble and insoluble forms. We also give the characteristics of their space-time variability. 相似文献
999.
Twenty-nine benthic invertebrate species were registered for the Gudauta Bank in the depth range of 8–32 m in 1990. The shallow-water
biocenose was defined for the depths of less than 10 m, the biocenoses of Anadara inaequivalvis and A. inaequivalvis-Upogebia pusilla occupied the depths of 10–30 m; and the biocenosis of Pitar rudis was found for the depths of more than 30 m. The highest biodiversity and abundance of benthos was registered for the Anadara biocenoses, while the lowest, for the shallow-water ones. It was found that significant changes in the benthic communities
took place in the forty years after the predator gastropod Rapana venosa was introduced into the Black Sea. The oysters became extinct on Gudauta Bank, and the species composition of the benthic
community has been significantly depleted. Alien species of Anadara and Rapana became the most abundant by biomass, comprising more than 80% of the total biomass of the benthos. The population density
of Rapana constituted 12 ind./m2 and was the highest ever registered for the studied areas of the Black Sea. Insufficient nutrition preconditioned the small
size of the mollusks. 相似文献
1000.
Seasonal evolution of surface mixed layer in the Northern Arabian Sea (NAS) between 17° N–20.5° N and 59° E-69° E was observed
by using Argo float daily data for about 9 months, from April 2002 through December 2002. Results showed that during April
- May mixed layer shoaled due to light winds, clear sky and intense solar insolation. Sea surface temperature (SST) rose by
2.3 °C and ocean gained an average of 99.8 Wm−2. Mixed layer reached maximum depth of about 71 m during June - September owing to strong winds and cloudy skies. Ocean gained
abnormally low ∼18 Wm−2 and SST dropped by 3.4 °C. During the inter monsoon period, October, mixed layer shoaled and maintained a depth of 20 to
30 m. November - December was accompanied by moderate winds, dropping of SST by 1.5 °C and ocean lost an average of 52.5 Wm−2. Mixed layer deepened gradually reaching a maximum of 62 m in December. Analysis of surface fluxes and winds suggested that
winds and fluxes are the dominating factors causing deepening of mixed layer during summer and winter monsoon periods respectively.
Relatively high correlation between MLD, net heat flux and wind speed revealed that short term variability of MLD coincided
well with short term variability of surface forcing. 相似文献