230柴油机超高增压系统选型研究

探讨了 ２０Ｖ２３０柴油机实现Ｐ_（ｍｅ）＝ ２．５ＭＰａ超高增压的技术途径,总结了目前的各种超高增压柴油机所采取的技术措施,分析了顾氏系统、相继增压系统和高工况放气系统的柴油机性能,提出了“相继增压与顾氏系统相结合的复合涡轮增压系统”,并对增压系统选型及整机布置进行了讨论。     

门式辐射检测装置对于集装箱码头安全的影响

“9·11”事件后,美国加强国内安全,同时为了防范可能利用港口设施对美国本土的恐怖袭击,在全世界范围内的大型港口积极推行“大港计划”等港口安全倡议,在相关港口安装辐射检测系统,阻止核和其他放射性材料的非法偷运到美国。本文根据门式辐射检测装置在斯里兰卡科伦坡南港的实施情况,介绍其系统组成,分析码头安全设施对于港口安全管理及运营的影响,对于我国大型集装箱码头提供参考及借鉴意义。     

Formulation of consistent nonlinear restoring stiffness for dynamic analysis of tension leg platform and its influence on response

Shortcomings of the traditionally used nonlinear restoring stiffness of TLPs, i.e. unrealistically high stiffness of horizontal motions, their uncoupling and secant formulation are pointed out. Therefore, new consistent restoring stiffness is derived. The platform is considered as a rigid body moored by flexible pretensioned tendons. Global horizontal low frequency motions (surge, sway and yaw) with large amplitudes as a result of dominant second order wave excitation and small stiffness, and vertical local motions (heave, roll and pitch) of higher frequency and small amplitudes excited by the first order wave forces, are distinguished. Hence, horizontal displacements represent position parameters in analysis of vertical motions. First, the linear restoring stiffness, which consists of the tendon conventional axial stiffness, the tendon geometric stiffness and the platform hydrostatic stiffness, is established. Then it is extended to large displacements resulting in new secant restoring stiffness. It depends on surge, sway and yaw displacements and is the same in any horizontal direction. Also, the tangent stiffness, which gives more accurate results, is derived. Heave is defined as vertical projection of axial tendon vibrations and platform tangential oscillations, which are analyzed in their natural moving coordinate system. Inertia force due to setdown, as a slave d.o.f. of the master horizontal motions, is taken into account in the dynamic equilibrium equations. As a result the complete tangential stiffness matrix of horizontal and vertical motions includes 7 d.o.f. The known secant restoring stiffness matrices are compared with the new one and noticed differences are discussed. All theoretical contributions are illustrated by relatively simple numerical example.     

Analysis of signal-obtaining error factor of sensor in gyro

The digital signal-obtaining for gyroscope is given. The single optic-fiber sensor via modulating intensity of light is used as measuring eonlponent . The influence on static transmission properties resulting from the special working environnlent （e. g. cryogenic and vacuum） ,the measure error because of tile reflector shape of rotor,the abnormity of facula from sensor caused by the existence of engraving error,and tile fixing error of sensor and the error of machine tool＇s initial lignnlent are investigated. The mathematic model in every condition is founded, the simulation and relative experiments ale done and the outeome is analyzed. The mathematic model and method of compensating technology are studied and some relative experiments are made. The result of study is usefid to improvement of the signal-obtaining system.     

Book reviews

R. S. Farrow, with J. M. Broadus, T. A. Grigalunas, P. Hoagland III, and J. J. Opaluch. 1990. Managing the Outer Continental Shelf Lands: Oceans of Controversy. New York: Taylor & Francis New York, 168 pp., paper.

Richard A. Kenchington. 1990. Managing Marine Environments. New York: Taylor & Francis, 248 pp.     

The passenger vessel services act and America's cruise tourism industry

The Passenger Vessel Services Act (PVSA) of 1886, a cabotage law, attempts to shield U.S. maritime shipping from foreign competition. It also applies to the U.S. cruise ship industry. The PVSA requires foreign cruise ships that carry passengers between U.S. ports to also stop at foreign ports. Norwegian Cruise Line America (NCLA), which operates one U.S. flagged cruise ship in Hawaii, wants the U.S. Customs and Border Protection to require foreign cruise ships offering Hawaii itineraries from the U.S. west coast to spend more time in foreign ports. We analyze the merits of NCLA's proposal. We argue that rather than making the PVSA even more protectionist, the law should be repealed.     

Book reviews

Coastal Resources Management: Beyond Market and Bureaucracy by Robert B. Ditton, John L. Seymour, and Gerald C. Swanson. Published by D. C. Heath and Company, Lexington, Massachusetts, 1977, 191 pp., 6 figures.

The Urban Sea: Long Island Sound by Lee E. Koppelman, Peter K. Weyl, M. Grant Gross, and DeWitt S. Davies. Published by Praeger Publishers, 1976. 209 pp., 81 figures, 42 tables.     

高置滑油循环柜在滑油系统中的应用

本文介绍高置滑油柜在滑油系统中的应用,阐明采用高置滑油柜可省略滑油抽吸泵的实用方法。     

Phytoplanktonic nutrient utilisation and nutrient signature in the Southern Ocean

The separation in Southern Ocean provinces of silicate excess at nitrate exhaustion and of nitrate excess at silicate exhaustion was already introduced by Kamykowski and Zentara (Kamykowski, D., Zentara, S.J., 1985. Nitrate and silicic acid in the world ocean: patterns and processes. Mar. Ecol. Prog. Ser. 26, 47–59; and Kamykowski, D., Zentara, S.J., 1989. Circumpolar plant nutrient covariation in the Southern Ocean: patterns and processes. Mar. Ecol. Prog. Ser. 58, 101–111) and our investigations of the silicate to nitrate uptake ratios confirm the earlier distinction. Oligotrophic antarctic waters mainly exhibit proportionally higher silicate removal what induces a potential for nitrate excess. The nitrogen uptake regime of such areas is characterised by low absolute as well as specific nitrate uptake rates throughout. Maximal values did not exceed 0.15 μM d⁻¹ and 0.005 h⁻¹, respectively. Corresponding f-ratios ranged from 0.39 to 0.86. This scenario contrasts strikingly to the more fertile ice edge areas. They showed a drastic but short vernal increase in nitrate uptake. Absolute uptake rates reached a maximum value of 2.18 μM d⁻¹ whereas the maximal specific uptake rate was 0.063 h⁻¹. In addition to an optimal physical environment for bloom development, accumulation of ammonium stimulated nitrate uptake in a direct or indirect way. Since ammonium build-up in surface waters traces enhanced remineralisation, release of other essential compounds during degradation of organic matter might have been the main trigger. This peak nitrate utilisation during early spring led to the observed potential for silicate excess. With increasing seasonal maturity the nitrate uptake became inhibited by the presence of enhanced ammonium availability (up to 8% of the inorganic nitrogen pool), however, and after a short period of intensive nitrate consumption the uptake rates drop to very low levels, which are comparable to the ones observed in the area of nitrate excess at silicate exhaustion.     

Practical estimation method of the design loads for primary structural members of bulk carriers

Various design loads used in the strength evaluation of ship structures have been introduced currently by classification societies. As most of these design loads have been determined as standard loads for the sake of convenience, the relationships between the design loads and the sea states actually encountered by ships seem to be weak. Accordingly, it may be difficult to refer and utilize them as fundamental design concepts for ship designers or as operational guidelines for ship operators. In view of this background, various efforts (Trans. West-Jpn. Soc. Nav. Archi. 89 (1995) 191; 93 (1997) 121; Jap Shipbuild. Mar. Eng. 2 (1967) 13; Proceedings of the 18th International Conference on Offshore Mechanics and Arctic Engineering 1999; Mar. Struct. 13 (2000) 495; J. Ship. Res. 45 (2001) 228; J. Mar. Sci. Technol. 6 (2002) 122; J. Soc. Nav. Archi. Jpn. 186 (1999) 319; Technical guide regarding the strength evaluation of hull structures, 1999; Proceedings of the 14th International Conference on Offshore Mechanics and Arctic Engineering, 1995; Mar. Struct. 10 (1997) 611; Proceedings of the Eighth International Symposium on Practical Design of Ships and Other Floating Structures, Shanghai, Vol. 2, China, 2001, p. 1089; Mar. Struct. 12 (1999) 171; Mar. Struct. 4 (1991) 295) have been made in recent years for developing estimation methods of the design sea states in a rational manner. Furthermore, for more practical purposes, the authors have developed practical estimation methods of the design sea states, the design regular waves and the design loads having transparent and consistent backgrounds to the actual loads acting on primary structural members of tankers (Mar. Struct. 16 (2003) 275).In this paper, it is firstly confirmed that the proposed methods for tanker structures can also be applied to the primary structural members of bulk carriers. Furthermore, the necessary modifications are carried out considering the specific structural types and loading conditions of bulk carriers in order to improve the estimating accuracy of the proposed design loads. Finally, comparisons between the results obtained by the structural analysis of a hold model applying the proposed design loads and long-term values of stresses by the most advanced direct structural analyses for different loading conditions are introduced and discussed in detail.     

一种支持网络协作的密钥管理协议

分布式网络协作是一种非常普遍的运行模式,分布式网络协作的安全性尤其重要,针对分布式网络协作的安全性提出了一套密钥管理协议,该协议基于IPSec体系结构,构造了一个用户、实体和实体之间的SPl的映射表,进而实现了网络协作的安全性.     

RV320工业机器人减速器中摆线齿廓的修形

RV320减速器是工业机器人专用减速器。要求承载力高,回差小,体积小等。机械结构中只有摆线结构符合需要,但通用结构中摆线轮为标准齿廓,间隙大、回差大,应用时就要对其进行改进。对摆线齿廓进行修形分析后,得出的修形参数能形成多齿啮合。同时在齿谷与齿顶间形成间隙形成油膜利于润滑。回差也大大缩小,经试验证明可满足高精减速器需要。     

The influence of different turbulence schemes on modelling primary production in a 1D coupled physical–biological model

A one-dimensional (1D) coupled physical–microbiological model has been applied to a site in the central North Sea. The impact of the choice of the turbulence closure scheme on the modelling the primary production has been investigated.The model was run with four different parameterisations of vertical mixing of heat, momentum and dissolved and suspended matters, using M2 tidal forcing and the hourly mean meteorological forcing of 1989 to reproduce the annual thermal structure and primary production. The four mixing parameterisations are: Level 2 turbulence closure scheme [Mellor, G.L., Yamada, T., 1974. A hierarchy of turbulence closure models for planetary boundary layers. J. Atmos. Sci. 31, 1791–1806; Mellor, G.L., Yamada, T., 1982. Development of a turbulence closure model for geophysical Fluid problems. Rev. Geophys. Space Phys. 20 (4) 851–875] using an explicit numerical scheme [Sharples, J., Tett, P., 1994. Modelling the effect of physical variability on the midwater chlorophyll maximum. J. Mar. Res. 52, 219–238]; a version of the Level 2.5 turbulence closure scheme [Galperin, B., Kantha, L.H., Hassid, S., Rosati, A., 1988. A quasi-equilibrium turbulent energy model for geophysical flows. J. Atmos. Sci. 45, 55–62; Ruddick, K.G., Deleersnijder, E., Luyten, P.J., Ozer, J., 1995. Haline stratification in the rhine/meuse freshwater plume: a 3D model sensitivity analysis. Cont. Shelf Res. 15 (13) 1597–1630] simplified to use an algebraic mixing length by Sharples and Simpson [Sharples, J., Simpson, J.H., 1995. Semidiurnal and longer period stability cycles in the Liverpool Bay region of freshwater influence. Cont. Shelf Res. 15, 295–313], also solved explicitly; the same simplified L2.5 scheme with an implicit numerical solution and modified vertical discretisation scheme [Annan, J.D., 1999. Numerical methods for the solution of the turbulence energy equations in the shelf seas. Int. J. Numer. Methods Fluids 29, 193–206]; and another version of the same scheme (but using a different algebraic mixing length) as described by Xing and Davies [Xing, J., Davies, A.M., 1996a. Application of turbulence energy models to the computation of tidal currents and mixing intensities in the shelf edge regions. J. Phys. Oceanogr. 26, 417–447; Xing, J., Davies, A.M., 1996b. Application of a range of turbulence models to the computation of tidal currents and mixing intensities in shelf edge regions. Cont. Shelf. Res. 16, 517–547; Xing, J., Davies, A.M., 1998. Application of a range of turbulence energy models to the computation of the internal tide. Int. J. Numer. Methods Fluids 26, 1055–1084]. Various model outputs at the sea surface and in depth profiles have been compared with data collected in 1989 as part of the North Sea Project [Huthnance, J.M., 1990. Progress on North Sea Project. NERC News, vol. 12, pp. 25–29, UK]. It is shown that the biological results are extremely sensitive to the small changes in the physical conditions, which arise due to the different turbulence schemes tested. The timing of the spring bloom and the maintenance of the midwater chlorophyll maximum all differ greatly between model runs, and the gross primary production varies by a factor of two from the highest to lowest results. The simplified Level 2.5 scheme, implemented using the numerical methods of Annan [Annan, J.D., 1999. Numerical methods for the solution of the turbulence energy equations in the shelf seas. Int. J. Numer. Methods Fluids 29, 193–206], produces results, which give the best agreement with the available data.     

21000t多用途船的球首设计及尾部节能装置试验

２１０００ｔ多用途船是上海远洋公司在南美洲航线上的定期班船，根据航程、船只数量、航班期的综合分析，要求船舶在主机输出功率７２３９．７５ｋＷ，含有１５％海上功率储备时，航速达到１６．５ｋｎ。为达到船东提出的先进航速指标，进行多次球首设计及尾部前置导管舵球的优化试验。介绍其设计思想及试验结果。     

船舶动力系统S.S.S离合器运动特性仿真研究

中继式S.S.S.离合器主要应用在燃气轮机驱动的动力系统,其运动规律对动力系统的传动/切换性能具有重大影响.阐述中继式S.S.S.离合器的结构运动,并建立其虚拟样机.在不同约束条件下,对中继式S.S.S.离合器运动过程进行动态仿真研究,得到中继式S.S.S.离合器的运动特性及的阻尼特性.     

The egg morphology of 7 Acartiidae species: a preliminary survey of the ootaxonomy of calanoids

This is the first contribution to acartiid taxonomy based on egg morphology. Eggs laid under laboratory conditions by maintaining female specimens of Acartia adriatica, A. clausi, A. italica, A. margalefi, A. tonsa, Paracartia latisetosa and Pteriacartia josephinae were studied by S.E.M. Most species produced eggs with intraspecific variation in their external morphology. In spite of such variation, however, it was possible to separate three species groups.     

U.S. ports: evolution and structure

U.S. ports are facing competitive pressures similar to those being felt by ports elsewhere around the world. Despite the public enterprise nature of U.S. port authorities, they tend to function as 'business-like' organizations. This enterprise-like approach stems from their evolution from being primarily private railroad ports in the 19th century to public competitive port authorities in the 20th century. This paper provides an overview of the evolution of U.S. ports and the ongoing effect of earlier legislation, the varied resulting institutional structures, and current national and regional level issues. Although there is no national ports plan or strategy in the U.S.A. (the Constitution limits federal actions in the ports field) the federal government is involved in providing dredging services through the Army Corps of Engineers, navigation aids via the Coast Guard and other minor port-related services. U.S. ports typically come under the jurisdiction of state or local governments. Increasing competition coupled with other port issues (growing financial constraints, difficulties in obtaining dredging permits, environmental concerns and restricted landside access) is forcing some U.S. ports to enter into strategic alliances with others at a regional level.     

Primary productivity of the Palmer Long Term Ecological Research Area and the Southern Ocean

A major objective of the Palmer Long Term Ecological Research (Palmer LTER) project is to obtain a comprehensive understanding of the various components of the Antarctic marine ecosystem. Phytoplankton production plays a key role in this so-called high nutrient, low chlorophyll environment, and factors that regulate production include those that control cell growth (light, temperature, and nutrients) and those that control cell accumulation rate and hence population growth (water column stability, grazing, and sinking). Sea ice mediates several of these factors and frequently conditions the water column for a spring bloom which is characterized by a pulse of production restricted in both time and space. This study models the spatial and temporal variability of primary production within the Palmer LTER area west of the Antarctic Peninsula and discusses this production in the context of historical data for the Southern Ocean. Primary production for the Southern Ocean and the Palmer LTER area have been computed using both light-pigment production models [Smith, R.C., Bidigare, R.R., Prézelin, B.B., Baker, K.S., Brooks, J.M., 1987. Optical characterization of primary productivity across a coastal front. Mar. Biol. (96), 575–591; Bidigare, R.R., Smith, R.C., Baker, K.S., Marra, J., 1987. Oceanic primary production estimates from measurements of spectral irradiance and pigment concentrations. Global Biogeochem. Cycles (1), 171–186; Morel, A., Berthon, J.F., 1989. Surface pigments, algal biomass profiles and potential production of the euphotic layer—relationships reinvestigated in view of remote-sensing applications. Limnol. Oceanogr. (34), 1545–1562] and an ice edge production model [Nelson, D.M., Smith, W.O., 1986. Phytoplankton bloom dynamics of the western Ross Sea ice edge: II. Mesoscale cycling of nitrogen and silicon. Deep-Sea Res. (33), 1389–1412; Wilson, D.L., Smith, W.O., Nelson, D.M., 1986. Phytoplankton bloom dynamics of the Western Ross Sea ice edge: I. primary productivity and species-specific production. Deep-Sea Res., 33, 1375–1387; Smith, W.O., Nelson, D.M., 1986. Importance of ice edge phytoplankton production in the Southern Ocean. BioScience (36), 251–257]. Chlorophyll concentrations, total photosynthetically available radiation (PAR) and sea ice concentrations were derived from satellite data. These same parameters, in addition to hydrodynamic conditions, have also been determined from shipboard and Palmer Station observations during the LTER program. Model results are compared, sensitivity studies evaluated, and productivity of the Palmer LTER region is discussed in terms of its space time distribution, seasonal and interannual variability, and overall contribution to the marine ecology of the Southern Ocean.     

基于联合动力的电力推进原动机并车过程研究

提出以联合动力作为船舶电力推进的原动机观点,着重分析了当一台原动机运行另一台原动机并入时传动系统关键部件三S离合器动力学特性.建立了原动机的数学模型,在MATLAB/simulink环境中进行了仿真试验.并在动力学仿真软件ADAMS的平台上建立了三S离合器的虚拟样机,使之与MATLAB环境中生成的主机模型进行数据通讯,从而对并车过程中的关键传动部件三S离合器传动特性进行了深入的分析,对并车过程系统的设计提供了借鉴经验.     

The economic impact study of maritime policy issues: application to the German case

Input-output analysis basically provides an estimation of a sector's economic impact by taking into account the indirect effects on all other sectors. For purposes of policy making, however, this may produce rather rigid and inaccurate results. This paper, therefore, introduces some extensions to the basic impact analysis. These extensions secure flexibility, completeness and accurateness of the outcomes. First, an accurate cost structure is determined in a bottom-up approach, i.e. by using data from a sample of representative companies. This allows for reliable outcomes and a flexible definition of sub-sectors. Secondly, the analysis is made in an intercountry context. Thirdly, the expenditure effects of generated income are determined by a macroeconomic module. Fourthly, company-level responses to alternative policy scenarios are investigated and translated into changing model parameters. These four basic elements are applied in a case study concerning the shipping sector of Germany. The scenarios are a continuation of the present policy, a laissez-faire policy, and two framework policies in which the government creates a favourable environment for shipping companies. For each scenario, the effects on value added, employment, tax revenues and expenditures are analysed and evaluated. This paper, thus, shows the relevance of accordingly amplified input-output analysis for policy purposes.