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1.
为了加强极地船舶船首强度,对极地航线冰况进行研究,提取真实极地航线的海冰数据,建立船舶航行冰况频谱表。对船舶首部采用构型全参数化设计,可保证在首部光顺的前提下进行自由变形。评估函数引入多目标线性规划思想,通过智能优化算法建立优化模型,最终建立极地船舶航行多冰况抗冰性能总收益最优的船舶型线优化设计方法。文中方法可对极地特定航线下的船首抗冰强度起到较好的优化作用。  相似文献   

2.
船舶优选航线的研究   总被引:2,自引:0,他引:2  
给出了优选航线的方法和数学模型,确定了船舶在大风浪中航行的临界速度和船舶运动性能函数,利用接收到的传真天气图和最新气候资料作优选航线的数据源,进行了模拟计算,结果表明该方法是可行的,在生产实践中有使用价值。  相似文献   

3.
船舶抗风浪等级的研究   总被引:5,自引:3,他引:2  
从船舶稳性,船舶强度和船舶运动理论出发,分析研究航次的特殊装载状态,提出了一种确定船舶抗风浪等级的简易方法,为船长选择航线提供了重要依据。  相似文献   

4.
对安装翼型硬帆船舶航线优化方法进行研究.以节能功率为航线优化设计的目标函数,综合考虑航海地理、海洋风况等因素,提出一种装帆船舶航线优化方法.以新加坡-台湾航线为例,对参考航线与现有航线进行计算分析,提出一条节能功率最大的优化航线.结果表明,安装风帆船舶在本文提出优化航线上航行时可比现有航线节省功率3.23%.  相似文献   

5.
针对船舶在海上航行时存在着航向偏离理想直航线的问题,确定了保持船舶航向稳定性的性能指标,并采用PID控制方法保持船舶航向的稳定性.仿真结果表明该方法是有效的.  相似文献   

6.
船舶最小事故航线选择方法研究   总被引:1,自引:0,他引:1  
提出了一种船舶最小事故航线的选择方法,这一方法的基本思路是先将船舶最小事故航线选择问题转化为一不含负权的最短路问题,然后再运用Dijkstra算法进行求解。  相似文献   

7.
论述用卫星导航仪等分距离设计大洋航线的方法,并用JLE3850卫星导航仪设计了从美国纽波特纽斯到好望角航线,为13.5万载货吨位船舶导航,取得了较好的效果,该方法简单、方便、实用且精度高。  相似文献   

8.
大圆航线和恒向线航线是远洋船舶常用的航线设计方法,理论上,可以通过航程节省率这个概念及计算公式,定量分析船舶航行时相同起止位置的大圆航线比恒向线航线节省航程。为了验证这个假设,分别采用墨卡托算法计算恒向线航程及大圆解析法计算大圆航程,比较二者的航程节省率,并用实例证实船舶在高纬度海区、航向接近东西向、横跨经度较大的情况下航行时,大圆航线更节省航程。  相似文献   

9.
张赫  闫建鑫  邢江豪 《科学技术与工程》2020,20(25):10511-10516
为实现船舶科学快速的到达目的地,通过结合海上船舶行驶的特点和影响因素建立了针对于船舶航行的海上航线诱导模型。首先根据影响船舶行驶的海风、波浪等因素和船舶自身情况求出船舶在风浪环境下行驶速度,进而求出风浪对航速的影响系数,然后利用改进的BPR公式和排队论的理论对船舶路段的行程时间进行计算,最后运用蚁群算法求出流量时变航路网中用时最短的路径。在进行建模时考虑了施工区的影响、不同位置风浪变化的影响以及碍航物的影响。研究表明:该模型在本算例中最佳航线比其他航线的最佳航线航行时间最高可减少6.4%,并且加入风浪等环境因素的影响使得结果更加准确,说明该方法能更好的为船舶航行提供帮助。  相似文献   

10.
针对集装箱环绕航线的箱量配置及效益评估问题直接影响航线的均衡运行和困扰提高航线经营管理质量问题,根据集装箱环绕航线的基本特征,通过对集装箱环绕航线理想模型的设定和分析,提出了集装箱环绕航线均衡运行原理,建立了船舶在各端港均衡作业量的数学模型.应用和解决了理想环绕航线集装箱总需备量和各挂靠港集装箱配置量的计算问题及航线的效益评估.填补了集装箱航线均衡运行理论的空白,为集装箱航线运行规律的深入研究奠定了理论基础,对指导集装箱航线资产的合理配置和提高航线的经营管理质量具有重要的现实意义.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

19.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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