准确确定海船初稳性高度界限面及综合稳性界限面的方法探讨

本文介绍了确定船舶初稳性高度界限面和综合稳性界限面的准确方法，通过对初稳性高度界限面问题的讨论，完善了载荷变动求取船舶初稳性高度变化量及改变载荷调整船舶初稳性高度的理论计算公式，并为船舶驾驶员在载荷变动时判断船舶初稳性高度的变化情况提供了准确可靠的方法。通过对船舶综合稳性界限面问题的讨论，建立了改变载荷求取船舶综合稳性变化量及调整船舶综合稳性的理论计算公式，为船舶驾驶员在载荷变动时判断船舶综合稳性的变化情况提供了准确可靠的方法。     

准确确定海船初稳性高度界面及综合稳性界限面的方法探讨

本文介绍了确定船舶初稳性高度界限面和综合稳性界限面的准确方法，通过对初稳性高度界限面问题的讨论，完善了载荷变动求取船舶初稳性高度变化量及改变载荷调整船舶初稳性高度的理论计算公式，并为 船舶驾驶员在载荷变动时判断船舶初稳性高度的变化情况提供了准确可靠的方法。通过对船舶综合稳性界限面问题的讨论，建立了改变载荷求取船舶综合稳性变化量及调整船舶综合稳性的理论计算公式，为船舶驾驶员在载荷变动时判断船舶综合稳     

船舶稳性与事故险情及责任的关系探讨

<正>适度的船舶稳性是船舶能够在水上安全航行最重要的因素,船舶稳性不足或过大,称为稳性不适度。船舶稳性不足,就是船舶不适航,船舶容易翻沉；船舶稳性过大,横摇周期过小,船舶会横摇剧烈；船舶在不适度的稳性状况下航行,会严重影响船舶操纵,既不能保障自身船舶安全,也会影响附近其它船舶的安全航行,甚至会引发船舶污染水域环境问题；     

岸边集装箱起重机整机运输船舶的稳性分析

为解决岸边集装箱起重机（简称岸桥）整机运输船舶的能力瓶颈问题,针对多装多载与船舶稳性之间的矛盾,通过分析表征船舶稳性的主要指标,比对装载不同数量、重量及重心高度的岸桥对船舶稳性的影响,提出在确保船舶稳性的条件下多装多运需采取的应对措施,并结合实例说明这些措施在改善整机运输稳性方面的可行性。     

浅析稳性计算与风浪中船舶操纵

船舶的安全检查有一项重要的内容,就是检查营运船舶的稳性资料及船长对船舶稳性的熟悉程度.船舶的稳性规范也指出,船舶稳性虽然已符合本规范的规定,但船长仍应对船舶在营运中的稳性负责.     

营运船舶的稳性问题

本文从船舶航海的实情出发,阐述了船舶稳性的含义及其校核方法;并就适度GM值和纵倾对稳性的影响进行探讨;评论了海协稳性标准(IMCO A.167决议)的欠缺,同时基于安全观点,提出了船舶营运时值得注意的几个问题——常数问题、合理配载、警惕随浪航行、严防货物移动、减少自由液面对稳性的影响以及集装箱船和滚装船的稳性问题。     

普通干货船载运散货强度与稳性校核分析

由于散装货物具有流动性，会对船舶稳性产生不利影响。本文从船舶检验的角度，探讨普通干货船载运散货，船舶结构强度和稳性校核的问题。     

半潜船完整稳性的初步研究

和其它类型船相比,半潜船的工况更复杂,船舶型线和用途也很特殊,使得稳性问题成为设计中一个重大的挑战。但目前还没有针对该类船舶的稳性规范,对该类船型开展稳性研究很有必要。通过1艘改装半潜船的稳性计算,发现航行状态下半潜船稳性特征与江船类似。而在下潜状态下,稳性随吃水增加而有所好转,在货物甲板出入水时稳性最差,此时可以采用纵倾来改善稳性。同时建立了依据完整稳性的船舶装载能力的数学模型。     

国内航行海船风浪中稳性事故统计及第二代完整稳性衡准研究展望

<正>船舶稳性是保证船舶航行安全的根本技术指标之一。我国现行的国内航行海船技术法规提供的完整稳性衡准解决处于瘫船状态时的船舶稳性安全问题,是基于事故经验和高度简化力学模型的技术要求。但海事事故统计分析表明,船舶实际遭遇恶劣风浪条件后还可能出现包括参数横摇、纯稳性丧失和过度加速度（谐摇）等模式在内的波浪中动稳性失效风险。     

海船稳性调整质疑及改正意见

对《船舶货运》、《货运技术》等教科书关于“船舶稳性调整”这一内容中存在的问题作了系统分析,提出了一些不同看法及修正意见,为船舶驾驶员在调整船舶稳性时提供了正确的方法,准确的计算公式及判别式,修正了在船舶稳性调整方面长期来存在的欠缺,对保障船舶的安全航行具有积极意义。     

联合作战计划和执行系统

全球指挥控制系统(GCCS)实施当前美国海军网络中心战信息基础设施的联合计划网络。联合作战计划和执行系统(JOPES)支持GCCS实现联合计划。JOPES有两类计划：时间不限的精密预案计划生成作战计划、方案计划或职能计划；时间敏感的危机行动计划生成作战命令或战役方案。前者在和平时期创建的作战计划是后者的计划基础，加速应付危机的能力。     

射频识别和全球定位系统联合的船舶监控系统

提出一种新设计的船舶监控系统——组合应用射频识别和全球定位系统的信息.详细论述了联合监控系统在解决船舶航行和停泊时的监控及实时信息采集的原理、功能和效果.根据射频识别技术和全球定位系统的技术特点,采用点状分布的射频识别设备记录船只停靠码头的时间,利用全球定位系统监控船只航行,使海洋航运企业对船只监控和人员管理更科学有效.     

印尼某电厂码头水工建筑物设计

印尼某电厂项目码头水工建筑物包括码头、防波堤和护岸等主要组成部分。在该项目水工建筑物的设计过程中,综合考虑当地的自然条件、施工能力和材料来源等因素,不断优化结构选型和结构断面。根据不同使用要求,护岸分别采用直立式和斜坡式2种结构型式,推荐的设计方案节省投资、施工方便,可供同类工程设计参考。     

柔性、刚性球艏对双壳舷侧结构耐撞性能影响的研究

采用非线性显示动力有限元软件LS_DYNA,对舷侧双壳结构在柔性和刚性球艏撞击下的动力响应进行仿真研究.采用全船有限元模型,考虑船体周围附连水质量对结构动力响应的影响.给出了碰撞力-撞深、能量-撞深曲线以及各构件吸收的能量.仿真结果表明:不同球艏撞击下舷侧内外壳板的破裂时刻、撞深和舷侧结构变形性能都有所不同.     

雷达/红外复合制导系统雷达对红外引导评估

对于雷达/红外复合制导系统,分析和推导了用雷达对红外成功引导概率的解析表达式,给出了该成功引导概率随一些特征参数变化的规律,仿真实验结果验证了引导概率的性质,从而对研究和设计雷达/红外复合制导系统具有一定的参考价值。     

基于STBC的多发射天线选择的传输性能研究

对于多发单收的天线系统(MISO),在已知信道状态信息(CSI)和等发射天线功率分配的情况下,利用反馈的CSI,对采用正交空时组码(STBC)的N选择n(N≥n,即n-NTx)的MISO系统进行研究。给出了求解选择性信道的序系数,推导了n-NTx系统的边缘概率密度函数(pdf)。在独立的平坦瑞利衰落信道中,完整地导出了n-NTx系统关于BPSK/QPSK调制的比特误码率(BER)性能界的理论表达式。为了与没有天线选择(即满复杂度)的系统进行性能比较,给出了BER的理论分析值和蒙特卡洛仿真结果,它们的结果均表明多天线选择系统能极大地提高系统的性能。     

Carbon flows in Baltic Sea food webs — a re-evaluation using a mass balance approach

The brackish Baltic Sea has been seen as particularly suitable for studies of food webs. Compared to fully marine ecosystems, it has low species diversity, which means fewer trophic linkages to analyse. The Baltic Sea is also one of the best-studied areas of the world, suggesting that most data requirements for food web models should be fulfilled. Nevertheless, the influence of physical and biological factors on trophic interactions and biogeochemical patterns varies spatially in the Baltic Sea, adding considerable complexity to food web studies. Food web structure and processes can be described and compared quantitatively between areas by estimating the flow of matter or energy through the organisms. Most such models have been based on carbon, though studies of complementary flows of other elements limiting production, such as nitrogen and phosphorus would be desirable. However, since ratios between carbon and other elements are used in calculating these flows, it is crucial, as a first step, to quantify the flows of carbon as accurately as possible.In this study, we used the EcopathII software (ver 3.1) to analyse models of carbon flow through the food webs in the three main areas of the Baltic Sea; the Baltic proper, Bothnian Sea and Bothnian Bay. A previously published study on carbon flow in the Baltic Sea [Elmgren, R. 1984. Trophic dynamics in the enclosed, brackish Baltic Sea. Rapp. P.-V. Reun. — Cons. Int. Explor. Mer. (183) 152–169.] was complemented with the data on respiration and flow to detritus [Wulff, F., Ulanowicz, R. 1989. A comparative anatomy of the Baltic Sea and Chesapeeake Bay ecosystems. In: F. Wulff, J.G. Field, K.H. Mann (Eds.), Flow Analysis of Marine Ecosystems: Theory and Practice. New York: Springer-Verlag.] in order to present complete mass balance models of carbon. The purpose of re-evaluating previous models with new analytic tools was to check how well their carbon flows balance, and to provide a basis for improved mass balance models using more recent data, including nutrients other than carbon.The resulting mass balance networks for the Baltic proper, Bothnian Sea and the Bothnian Bay were shown to deviate from steady state. There was an organic carbon surplus of 45, 25 and 18 g C m⁻² year⁻¹ in the pelagic zones of the Baltic proper, Bothnian Sea and Bothnian Bay, respectively. The Ecopath network analysis confirmed that the overall carbon flow was highest in the Baltic proper, somewhat lower in the Bothnian Sea and much lower in the Bothnian Bay. The only clear differences in food web structure between the basins was that the average trophic level was lower for demersal fish in the Bothnian Sea and higher for macrofauna in the Bothnian Bay, compared to the other basins. The analysis showed weakness in our current understanding in Baltic Sea food webs and highlighted areas where improvements could be made with more recent data.     

Parameterisation of clastic sediments including benthic structures

The sediment transport processes in the south-western Baltic Sea are predicted by means of a numerical model in the project DYNAS. There are two sediment parameters that influence the results of modelling remarkably: critical shear stress velocity and bottom roughness. This paper presents the way how to parameterise these factors and extrapolate them into the investigation area. The critical shear stress velocity is parameterised basing on grain size data, combining approximations after Hjulström [Hjulström, F., 1935: Studies in the morphological activity of rivers as illustrated by the river Fyris. Geological Institution of University of Uppsala: Bulletin (25): 221–528.], Shields [Shields, A., 1936: Anwendung der Ähnlichkeits-Mechanik und der Turbulenzforschung auf die Geschiebebewegung. Mitteilungen der Preussischen Versuchsanstalt für Wasserbau und Schiffahrt (26): 26 pp.] and Bohling [Bohling, B., 2003: Untersuchungen zur Mobilität natürlicher und anthropogener Sedimente in der Mecklenburger Bucht. unpublished doctoral thesis, Mathematisch-Naturwissenschaftliche Fakultät, Ernst-Moritz-Arndt-Universität Greifswald/Germany, 156 pp.]. The roughness length, in the case of absence of macro zoo-benthos and their structures, is parameterised basing on grain size too employing Soulsby [Soulsby, R.L., 1997: Dynamics of Marine Sands: a Manual for Practical Applications. London, Thomas Telford Publications. 249 pp.], Nielsen [Nielsen, P., 1983: Analytical determination of nearshore wave height variation due to refraction shoaling and friction. Coastal Engineering 7, 233–251.] and Yalin [Yalin, M.S., 1977: Mechanics of Sediment Transport. Pergamon Press, New York. 298 pp.]. No equivalent simple parameterisations for biologically caused bed roughness exist. Here, findings of Friedrichs [Friedrichs, M., 2004: Flow-induced effects of macro zoo-benthic structures on the near-bed sediment transport. Dissertation, Universität Rostock, 80 S.] and estimations by the DYNAS biologists group were combined in order to derive roughness lengths from abundance measurements of four previously selected key species which represent the originators of the dominating benthic structures at the sea floor in the south-western Baltic Sea. Critical shear stress velocity and bed roughness are known at few sample sites only. They were extrapolated into the larger investigation area using a proxy-target concept. The mean near bottom milieu (bathymetry, median grain size, salinity, oxygen) which was derived using results from numerical modelling serves as the proxy. Since the milieu parameters are measured at the sampling sites for which the target parameters have been determined, a combined hierarchical and supervised classification was employed to transfer the local knowledge into the unknown investigation area.     

船舶主机缸套裂纹起因及其对策

论述船舶主机缸套产生裂纹的原因和易出现裂纹的部位，提出了避免裂纹产生的措施和主机日常管理中应注意的事项，指出合理得当的操作和适当的保养可以避免一些裂纹的产生，延长主机的使用寿命。     

单相PWM整流器的建模与仿真分析

文章详细分析了单相VSR型PWM整流器的整流原理,建立了电流内环,电压外环的单相VSR型PWM整流控制器的数学模型和逻辑框图。在MATLAB／Simulink软件环境中进行了仿真,分析了模型的可行性。