Penning trap mass measurements on nobelium isotopes

The Penning trap mass spectrometer SHIPTRAP at GSI Darmstadt allows accurate mass measurements of radionuclides, produced in fusion-evaporation reactions and separated by the velocity filter SHIP from the primary beam. Recently, the masses of the three nobelium isotopes No252-254 were determined. These are the first direct mass measurements of transuranium elements, which provide new anchor points in this region. The heavy nuclides were produced in cold-fusion reactions by irradiating a PbS target with a Ca-48 beam, resulting in production rates of the nuclei of interest of about one atom per second. In combination with data from decay spectroscopy our results are used to perform a new atomic-mass evaluation in this region.

On-line voltammetric monitoring of dissolved Cu and Ni in the Gulf of Cadiz, south-west Spain

Geochemical processes in estuarine and coastal waters often occur on temporally and spatially small scales, resulting in variability of metal speciation and dissolved concentrations. Thus, surveys, which are aimed to improve our understanding of metal behaviour in such systems, benefit from high-resolution, interactive sampling campaigns. The present paper discusses a high-resolution approach to coastal monitoring, with the application of an automated voltammetric metal analyser for on-line measurements of dissolved trace metals in the Gulf of Cadiz, south-west Spain. This coastal sea receives metal-rich inputs from a metalliferous mining area, mainly via the Huelva estuary. On-line measurements of dissolved Cu, Zn, Ni and Co were carried out on-board ship during an eight-day sampling campaign in the study area in June 1997. A pumping system operated continuously underway and provided sampled water from a depth of ca. 4 m. Total dissolved metal concentrations measured on-line in the Gulf of Cadiz ranged between <5 nM Cu (<3 nM Ni) ca. 50 km off-shore and 60–90 nM Cu (5–13 nM Ni) in the vicinity of the Huelva estuary. The survey revealed steep gradients and strong tidal variability in the dissolved metal plume extending from the Huelva estuary into the Gulf of Cadiz. Further on-line measurements were carried out with the automatic metal monitor from the bank of the Odiel estuary over a full tidal cycle, at dissolved metal concentrations in the μM range. The application confirmed the suitability of the automated metal monitor for coastal sampling, and demonstrated its adaptability to a wide range of environmental conditions in the dynamic waters of estuaries and coastal seas. The near-real time acquisition of dissolved metal concentrations at high resolution enabled an interactive sampling campaign and therefore the close investigation of tidal variability in the development of the Huelva estuary metal plume.

Automated voltammetric system for shipboard determination of metal speciation in sea water

An automated and semi-intelligent voltammetric system is described for trace metal analysis. The system consists of a voltammeter interfaced with a personal computer, a sample changer, 2 peristaltic pumps, a motor burette and a hanging mercury drop electrode. The system carries out fully automatically approximately 5 metal determinations per hour (including at least 3 repetitive scans and calibration by standard addition) at trace levels encountered in clean sea water. The computer program decides what level of standard addition to use and evaluates the data prior to switching to the next sample. Alternatively, the system can be used to carry out complexing ligand titration with copper whilst recording the labile copper concentration; in this mode up to 8 full titrations are carried out per day. Depth profiles for chromium speciation in the Mediterranean Sea and a profile for copper complexing ligand concentrations in the North Atlantic Ocean measured on board-ship with the system are presented. The chromium speciation was determined using a new method to differentiate between Cr(III) and Cr(VI) utilizing adsorption of Cr(III) on silica particles.

船载综合信息显示系统半实物仿真设计与实现

针对船载综合信息显示系统在实体船舶内开发不方便的问题,提出了一种半实物仿真系统的设计与实现方法。结合"科学三号"海洋科学考察船的综合信息显示系统的设计和开发过程,从体系结构、信息流程和实现方法3个方面对半实物仿真系统的设计和实现过程进行了探索。实践结果表明,这种半实物仿真系统一方面可以为实际系统的体系结构、信息流程设计提供支持,另一方面可以为实际系统应用软件的开发提供较为真实的环境,有效的缩短开发时间和降低开发风险。

Characteristics of nonlinear internal waves observed in the northern South China Sea

The South China Sea (SCS) is one of the most active areas of internal waves. We undertook a program of physical oceanography in the northern South China Sea from June to July of 2009, and conducted a 1-day observation from 15:40 of June 24 to 16:40 of June 25 using a chain of instruments, including temperature sensors, pressure sensors and temperature-pressure meters at a site (117.5A degrees E, 21A degrees N) northeast of the Dongsha Islands. We measured fluctuating tidal and subtidal properties with the thermistor-chain and a ship-mounted Acoustic Doppler Current Profiler, and observed a large-amplitude nonlinear internal wave passing the site followed by a number of small ones. To further investigate this phenomenon, we collected the tidal constituents from the TPXO7.1 dataset to evaluate the tidal characteristics at and around the recording site, from which we knew that the amplitude of the nonlinear internal wave was about 120 m and the period about 20 min. The horizontal and vertical velocities induced by the soliton were approximately 2 m/s and 0.5 m/s, respectively. This soliton occurred 2-3 days after a spring tide.

极化SAR图像海面船只监测方法研究

船只监测不论是在民用还是军用方面都有广阔的应用前景。极化合成孔径雷达（PolSAR）可以测量目标的极化散射特性，能够提高舰船检测的准确度和分类精度。论文以工程应用为背景，以深刻理解PolSAR图像成像原理及理论为基础，重点围绕PolSAR图像船海对比度增强和海上目标识别等方面开展了研究。 本文在文献综述的基础上，全面分析了单极化和PolSAR图像舰船目标检测的研究现状。在现有的PolSAR图像目标检测方法基础上，针对双极化数据首次提出二维卷积方法提高船海对比度；针对全极化数据改进广义最优化方法，构造极化特征向量，将回波强度和极化散射特征有机结合，提高船海对比度。上述两种方法能解决船只回波强度和海面回波强度相近或高海况下船目标检测问题。将聚类方法应用到海上目标识别中，采用非监督分类-模糊聚类可以将船只、海上人造目标、船尾迹等识别开来，在海上目标识别方面将有广阔的应用前景。 应用极化电磁波基本理论，将极化熵概念应用到船只监测。首次采用Bragg模式和双尺度模式分析两种不同极化熵随着入射角、波数和风场的变化情况，从而确定在低风速下Cloude熵相对Touzi熵更适合船只监测。

基于3自由度并联机器人的船载炮6维运动模拟系统

本文系统基于3自由度并联机器人和3维图形仿真实现了空间6维运动的模拟，构造了一种3自由度并联机构来模拟船的3维转动，并给出了并联平台的运动学逆解，采用图形仿真虚拟作战环境，模拟船的3维移动，并分析了图形驱动原因。

基于并联机器人的船载炮半物理仿真试验系统研究

20世纪90年代以来，并联机器人被广为注意，成了机器人技术新的热点。并联机器人技术被广泛地应用在工业、航天、航海等领域，尤其是并联机床，佩一出现就引起了广泛的关注，被称为是“21世纪的机床”，“20世纪机床首次革命性改型”。为了提高船载炮射击训练效益，解决船载炮兵训练的保障问题，同时也为船载炮兵训练的保障工作探索新的路子，提出研制基于并联机器人的船载炮半物理仿真试验系统，使训练可以不受天气、场地的限制。本系统采用模拟船、操瞄炮等设备与计算机图形虚拟技术相结合的方式组成船载炮半物理仿真试验系统。系统既要虚拟船载炮的作战环境，又要实现船在海浪中的6维运动。采用3自由度并联机器人平台构建模拟船，实现船的3维转动；采用计算机仿真虚拟作战环境，并实现船的3维移动。本文介绍了整个系统的软硬件构成，硬件从三自由度并联机构的运动学到控制系统的结构，软件从形成虚拟视景的图形驱动原理到主程序界面，最后展示了系统的硬件实物和软件界面的照片。基于并联机器人的船载炮半物理仿真试验系统具有以下特点：1．采用变频调速技术，研制了三自由度并联机构模拟系统，实现了船炮平台的运动模拟，使系统具有负载能力强、成本低、性能可靠等特点。2.整个系统由计算机图形分系统、动态数据采集与处理分系统、船的运动模拟分系统等组成，实现了船载炮兵射击指挥和火炮操作的模拟训练。 3．应用了多传感器信息融合技术，实现了多信息实时处理，达到了实时仿真的要求。系统能够实时检测船姿态和火炮操作状态等信息，评价射击效果。4.采用三自由度的旋转模拟与图像三自由度的平移运动相结合的方法，实现了六自由度的炮目相对运动模拟效果。该系统可用于模拟炮兵部队实施渡海登陆作战，对岸防目标、海上目标射击和指挥训练。完成船载炮兵的火炮操瞄和射击指挥的教学、训练及考核任务。

有缆水下机器人主动升沉补偿控制研究

针对母船的升沉运动影响有缆水下机器人的释放与回收的工程实际需求,提出了利用液压绞车降低中继器的升沉速度来实现水下机器人主动升沉补偿控制的方法,来提高水下机器人释放与回收的安全性能。建立液压绞车的数学模型并设计主动升沉补偿前馈控制器。水下机器人主动升沉补偿实验表明液压系统的非线性降低了液压绞车主动升沉补偿前馈控制的升沉补偿效率。针对液压绞车的非线性特性,设计了液压绞车主动升沉补偿预测控制算法,仿真实验表明基于液压系统参数辨识的液压绞车主动升沉补偿预测控制可以得到较高的升沉补偿效率。

水下机器人主动升沉补偿系统研究

介绍一种基于水下机器人常规液压收放绞车的主动升沉补偿系统,利用加速度传感器获得母船的升沉运动信号,控制绞车的运转来降低母船的升沉运动对水下机器人的影响。通过理论计算建立主动升沉补偿系统的数学模型,仿真分析绞车运动对水下机器人升沉运动的补偿效果,并利用主动升沉补偿系统实验台验证基于常规液压收放绞车的主动升沉补偿方案的可行性。

基于信道估计的RS纠错编码改进算法的设计与实现

提出了一种基于信道估计的RS纠错编码改进算法,该算法可以自适应地根据外界条件和环境对传输信道的干扰变化实时地调节编码系统的数据冗余量。仿真与完整的分析结果证实了该改进算法有效地改善了RS编码算法的传输效率;并且通过实际应用表明:良好的性能,高容错性适应于该通信系统的多种传输信道,具有很强的实用性。

蠕动爬行攻泥机构转向工作特性的有限元分析

针对用于沉船打捞的水下攻泥机器人蠕动爬行攻泥机构的结构与工作机理 ,建立了适当的有限元计算模型 ,进而通过弹塑性有限元计算 ,模拟了攻泥机构处于土中不同深度的工作情况 ,建立了攻泥机构前进位移V和转向角θ之间关系的通用公式。通过它可以实现对攻泥机构前进路线的规划与自动控制

港口业船舶优化调度模型设计

以港口船舶计划调度为研究背景 ,分析了港口业计划调度的特征 ,提出了生产计划调度的系统框架 ,并在此基础上建立了以船舶拖期惩罚费用为最小 ,多种因素约束下的调度模型 ,将人工智能技术应用到实际生产调度中 ,实现分层次、分级研究多种资源约束条件下的计划调度和优化

一个CIMS环境下的基于范例的船体装配CAPP系统

本文介绍了一个 CIMS环境下的基于范例的船体装配 CAPP系统 .包括 :CAPP系统在渤海造船厂 CIMS工程中的地位 ,基于范例的工艺规划 (范例的表达 ,范例的索引、存储、检索和适应 ) ,工艺定额和材料定额制定 ,分系统之间的信息集成 .系统采用 Power Builder和 SQL Server数据库中的 SQL语言编写 .目前 ,船体装配 CAPP系统已经在渤海造船厂的微机上连网运行

International transport costs and the margins of Intra-Latin American maritime trade.

This paper focuses on the analysis of the relationship between maritime trade and transport cost in Latin America. The analysis is based on disaggregated (SITC 5 digit level) trade data for intra Latin maritime trade routes over the period 1999-2004. The research contributes to the literature by disentangling the effects of transport costs on the range of traded goods (extensive margin) and the traded volumes of goods (intensive margin) of international trade in order to test some of the predictions of the trade theories that introduce firm heterogeneity in productivity, as well as fixed costs of exporting. Recent investigations show that spatial frictions (distance) reduce trade mainly by trimming the number of shipments and that most firms ship only to geographically proximate customers, instead of shipping to many destinations in quantities that decrease in distance. Our analyses confirm these findings and show that the opposite pattern is observed for ad-valorem freight rates that reduce aggregate trade values mainly by reducing the volume of imported goods (intensive margin).