首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
3.
Comment on BFI     
Almost everyone working in shiPPingcircle 15 familiarwith BFI(Baltiefreightindex),andeallitasaweatherglassreflecting the global dry bulk shiPPing market.Can BFIrefleets fully and truthfully the global dry bulk market?The comPonent routes of BFI(no more than 15脾ars old)10一10一10一10一10一10一75一10一7.5一75一书 USG/Contlnent Tansat{antie rOUnd USG/JaPan skaw/USG/A 3ia Paeifie NoPaC/Japan Transpae币e roundHamPton Roads/RotterdamE Asia/NoPaC/SkawPassoro T口ba旧O/ROtterdam T…  相似文献   

4.
1Introduction Asfarascomplexsystemisconcerned,ithasmore subsystemsbelongingtodifferenthierarchiesthanthe simplesystem.Atthesametime,therelationshipbe tweendifferentsubsystemsbecomesmoreandmore complex.Itisdifficulttogivethequantitativemodels ofcomplexsyst…  相似文献   

5.
The underwater target recognition is a key technology in acoustic confrontation and underwater defence. In this article, a recognition system based on fuzzy logic inference (FLI) is set up. This system is mainly composed of three parts : the fuzzy input module, the fuzzy logic inference module with a set of inference rules and the de-fuzzy output module. The inference result shows the recognition system is effective in most conditions.  相似文献   

6.
[Objective]The propulsion shafting system is an important part of a ship, and the bearing load directly affects its operating state and service life. In this paper, bearing load under hull deformation is studied using grey system theory. [Method] First, according to the empirical formula of the relative displacement of each bearing caused by the deformation of the hull of a 57 000 DWT oil tanker, the relative displacement of each bearing is calculated and input into a finite element model, and the load value of each bearing is output. On this basis, grey relationship analysis of grey system theory is introduced to study the influence degree of stern bearing displacement on the load of each bearing, and the relative change of the load of each bearing caused by the displacement of the stern bearings is analyzed. A GM (1,1) prediction model is then established for the bearing load considering the bearing displacement conditions, and the hull deformation-fitting and prediction of each bearing load are made. [Results]The results show that grey relationship analysis can effectively reflect the influence of hull deformation on bearing load. The GM (1,1) prediction model has high accuracy and prediction errors less than 6.0%, and the model test indexes can represent the accuracy of the prediction. [Conclusion]Grey system theory is effective and practical in research on propulsion shaft load. It can accurately predict bearing load under bearing displacement, giving it certain reference value for research on bearing load under actual sailing conditions. © The Author(s) 2022.  相似文献   

7.
In this paper, sound scattering from the sea surface in the Persian Gulf region is investigated. Chapman-Harris and Ogden-Erskine empirical relations coupled with perturbation theory are implemented. Based on the Ogden and Erskine’s experiments, sound scattering from the sea surface has three different regimes in which two mechanisms of surface roughness and subsurface bubble clouds are involved. Ogden-Erskine’s scattering relation which consists of perturbation theory and Chapman-Harris’ s scattering terms are verified by the experimental data of Critical Sea Tests 7. Subsequently, wind speed in the Persian Gulf is provided based on three data bases of Arzanah station, ERA40, and PERGOS. Accordingly, surface scattering strength in the Persian Gulf region is calculated at different grazing angles, frequencies and provided wind speeds. Based on the resulted values of scattering strength, scattered intensity from the sea surface is also studied. These studies indicate that both scattering strength and scattered intensity generally increase as grazing angle, frequency and wind speed increase.  相似文献   

8.
A lthough many Chi nese businesses stilldeliver their products to retail-ers themselves, China's profes-sional logistics industry hasbeen growing at a rocketing an-nual rate. The three countries, China,Japan and South Korea, boast-ing big trade volumes, showmuch potential for co-operation. TNT will grow as a com-pany with China, and to helpChina grow with activities in-strumental to the further eco-nomic development of China. Standardization will helpimprove the efficiency of logis-tics an…  相似文献   

9.
Although many Chinese businesses still deliver their products to retailers themselves, China's professional logistics industry has been growing at a rocketing annual rate.  相似文献   

10.
Through analyzing the roll model of the integrated system of fin and anti-rolling tank, this paper uses binomial equation to simplify the module and check how the approximate parameters simulate the original function. Based on the simplified module, the influence of fin and anti-rolling tank on the coefficient items of the roll module is discussed, and the influencing factors between fin and anti-rolling tank are analysed. And through simulation, the influence of action between fin and anti-rolling tank on the static characteristics, and the integrated stabilization effect, are analyzed.  相似文献   

11.
The appropriate prediction of the hull deflection of a severely damaged warship is an important area in the research of the warship survivability. In this paper, the asymmetrical beam bending theory is applied to set up the damaged model, a comparison of the longitudinal strength, the deflections of damaged hull subjected to both hagging and sagging moments, and shear forces is carried out. The external loads are also calculated according to different damaged positions. Finally, some results and conclusions are obtained.  相似文献   

12.
In order to respond the discredit on the design wave standard and to recommend new consideration on design wave parameters,based on the long-term distribution of statistic characteristics of waves and the short-term probability properties of sea state defined by giving the return period,the calculation of the return period,the height,the period,and the oceanic wave parameters of the design wave and the forecasting methods are discussed in this paper.To provide references for the operation reliability of floating structures in the extreme sea state,the method of determining the design wave parameters is resurveyed.A proposal is recommended that the design wave,which can be either significant wave with 500-year of the return period,or the maximum wave with 1/N of exceeding probability,100-year of the return period,can be applied in the engineering design practice.  相似文献   

13.
Over 500 people of the shipping and transport fraternity gathered at Darling Harbor in Sydney on 17 October for the Australian Shipping and Transport Awards 2001 hosted by Lloyd's List DCN. Through shipping and transport industry voting, COSCO has overcome strong competition on the Australia/East Asia trade to become winner of Customer Service Award. Other awards include three Highly Commended Award for Customer Service on the Australia/North Asia trade, and Sailing Schedule Reliability on both Australia/East Asia and North Asia trades. This is the sixth time for COSCO to be rewarded by Australian shipping industry. The awards show that  相似文献   

14.
China's economic upsurge cannot be reversed by the severe acute respiratory syndrome (SARS) now ravaging some parts of the country. China's economy will maintain its steady growth momentum despite the SARS' impact to some extent on investment, consumption and  相似文献   

15.
Many recent studies have confirmed the existence of liquid slip over particular types of solid surfaces, and these so-called super-hydrophobic surfaces have been shown to generate effective liquid slip because of the air trapped between the surface structures. In this paper, based on boundary layer theory, the microscopic structure of the super-hydrophobic surface is analyzed. The liquid slip effect on friction-reduction over super-hydrophobic surfaces under various flow conditions is investigated by experiments with a flume and water tunnel. The experimental results show that the greatest amount of drag-reduction that can be achieved is 8.76% at a low Re.  相似文献   

16.
Longitudinal and horizontal vibration must both be reduced in an effective vibration isolation system. We present a cylindrical shell vibration isolator as a dynamic system composed of four springs and dampers. Vibration is directly produced by the motion of machinery, and more is subsequently generated by harmonic frequencies within their structure. To test the effectiveness of our isolator, we first determined equations for the transmission of vibration from the machine to its cylindrical shell. Damping effects produced by the vibration parameters of our system are then analyzed.  相似文献   

17.
all hands on board 英语单词中常有一字多义,但拼法、读音完全相同,弄不好就出问题。比如: 一个略通英语的法籍海员,一天听到英籍船长命令“all hands on board”,只见各船员出室纷纷跑上甲板,他也赶快跑上甲板,忙将双手按在甲板上,船  相似文献   

18.
This paper addresses issues of cruise home port competition based on the cruise supply chain. A pricing model of the cruise market is developed considering the competitive cooperation behaviors of the participants in the cruise supply chain. Furthermore, a model of cruise home port competition is developed to investigate the impacts of subsidy participants in the cruise supply chain on cruise home ports. The results indicate that subsidy policies change the market equilibrium, promote the upstream and downstream integration of cruise supply chain, and enhance cruise home port competitiveness. Subsidies to cruise line increase the payoffs of cruise supply chain and ports’ profit. Subsidies to travel agency decrease passenger costs and improve all ports’ profits. For the long-term development of cruise home port, the consequents can be used as policy suggestions.  相似文献   

19.
Study on the application of spectral fatigue analysis   总被引:2,自引:0,他引:2  
1Introduction Fatiguefailurehaslongbeenanimportantissuefor shipsandoffshorestructures.Toensuresufficientfa tiguestrengthduringtheservicelife,afatiguestrength assessmentneedstobedoneatthedesignstage.Gen erally,methodsforassessingfatiguestrengthcanbe classi…  相似文献   

20.
1 Introduction1 The underwater acoustic communications are needed for military affairs and commercial fields. There are lots of applications of underwater acoustic communications, such as in oceanographic data collection, exploration of natural undersea r…  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号