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Convergence Characteristics of an Acoustic Aplanatic Lens
Convergence Characteristics Acoustic Aplanatic Lens
2009/8/19
An acoustic aplanatic lens is designed by the optical method. It can remove spherical and coma aberrations in the paraxial area. Sound pressure fields of the bi-concave aplanatic lens and a spherical ...
Speed-Up of Acoustic Propagation Program by Time-Domain Difference Method Using a Supercomputer
Acoustic Propagation Program Time-Domain Difference Method Supercomputer
2009/8/19
The FDTD (Finite Difference Time Domain) method is a simple and high-precision numerical method in the underwater acoustic field. For large-scale underwater acoustic field simulations with the FDTD me...
Lumped Parameter Equivalent Circuit Analysis of the Multiport Transducer
Lumped Parameter Equivalent Circuit Analysis Multiport Transducer
2009/8/19
The multiport transducer developed by Dr. J. L. Butler is a novel low-frequency underwater acoustic source using free-flooded resonance cavity chambers with both the inside and outside driving surface...
Focusing Properties of Bicylindrical Acoustic Lenses
Acoustic lens Bicylindrical lens Focusing
2009/8/19
This theoretical report concerns the focusing of a plane progressive acoustic wave by a bicylindrically-curved lens. It was assumed that the lens was made of polymethylmethacrylate (PMMA) and was subm...
基于QFT的船舶航向控制器设计与仿真研究
定量反馈理论（QFT） 船舶航向控制 鲁棒控制器
2009/7/21
论述了基于定量反馈理论（QFT）的船舶航向控制器的设计方法。该方法不仅能保证闭环系统有较强的鲁棒性，还具有良好的动静态特性，特别是在系统的快速性方面较其它设计方法有较大的改善和提高。基于MATLAB的仿真实验表明运用该方法所设计的控制器具有较强的鲁棒性和自适应能力，满足性能指标的要求，具有较高的工程应用价值。
影响船舶雾航安全的人为因素分析及对策
雾航安全 人为因素 主要表现
2009/6/22
海雾是影响船舶航行的不安全因素，本文论述了人为因素在船舶雾航安全中的重要性，分析了影响船舶雾中航行安全的人为因素的主要表现，并提出了消除船舶雾航中不良人为因素的对策。
应进一步完善船舶压载水管理
船舶压载水 航运业
2009/6/19
船舶压载水主要是为确保船舶在空载或不满载情况下的稳性和浮态，而在船舶离港前用海水在其压载舱中打入压载水，并在抵达预定港口装货前，将压载水逐渐排空，以便船舶可以最大限度地装载货物。船舶在打入压载水的同时，也将海洋水生物带入压载舱中，而在另外一处港口的海洋环境中打出压载水，也将这些异地水生物带入另一海洋环境，从而对新的海洋环境的生态造成影响和破坏，有时甚至是致命的破坏。
A Prediction Method of Travel Demand of Cruise Ships in Japan
Tour Selection Model Characteristic Tours Potential Share Cruising Demand Economical Analysis
2009/5/19
In the present study, a new prediction method of travel demand of cruise ships is proposed in which the characteristic of each demand for choosing a tour, the characteristics of tours, and factors of ...
A Proposal of Guidance to the Master of a Damaged Passenger Ship for Deciding to Return to Port
Damaged Passenger Ship Port Proposal of Guidance
2009/5/4
At the International Maritime Organization (IMO), guidelines for reference by masters in assessing operational damage stability for safe return to port by own power or tow is to be developed. To contr...
Observation of Artificial Structures by Autonomous Underwater Vehicle
Artificial Structures Autonomous Underwater Vehicle
2009/4/30
There is a great demand for Autonomous Underwater Vehicles (AUVs) not only for wide area surveys but also for condition surveys of artificial underwater structures such as breakwater caissons, pillars...
Intrusion Depth of Discharged Water from Ocean Nutrient Enhancer “TAKUMI” into the Sea with Temperature Stratification
model experiments numerical calculations TAKUMI temperature stratification
2009/4/30
In this paper, model experiments and numerical calculations were performed in order to clarify the behavior of the discharged water from the ocean nutrient enhancer “TAKUMI” into the sea with temperat...
Investigation on Components of Added Resistance in Short Waves
Components Added Resistance Short Waves
2009/4/10
In order to estimate decrease of ship speed in actual seas, it is important to calculate added resistance in waveswith accuracy. Especially added resistance in short waves is one of the predominant fa...
舷侧阵声纳的基阵结构和性能评估
舷侧阵声纳 基阵结构 性能评估
2009/3/19
早在50年代美国就已经开始研究潜装的舷侧阵声纳，曾在“飞鱼”号潜艇
两侧安装了长达61米的舷侧阵。当时使用的基阵传感器元件是压电陶瓷。由于
潜艇本身的自噪声太大，又没有研制出新的声学材料，使得这种舷侧阵声纳仅
做了试装就销声匿迹了。时过30多年，到80年代中期，舷侧阵声纳的研究又重
新受到重视，而且一举获得了成功。其主要原因是这种声纳的工作环境发生了
很大变化。潜艇自噪声变得很低，一些新...
数学形态学在声纳信号处理方面的应用研究
数学形态学 结构元素 信号变换
2009/3/9
本文是在深入研究数学形态学基本理论的基础上，编写一维信号形态处理函数，包括腐蚀、膨胀、开、闭等多种形态运算，并应用这些基本函数对一维信号的降噪滤波特性予以仿真分析，结构元素在数学形态学中是一个非常重要的概念，本文分别就其形状、长度、幅度等参数考察其对滤波效果的影响，在本文的后半部分，应用小波及形态滤波方法对混入随机噪声的正弦信号进行滤波，仿真结果表明对于高、单频加噪信号，采用形态学滤波方法比采用小...