美国水雷作战能力现状与发展研究

从水雷装备和布雷能力 2 个方面介绍了美国水雷作战能力现状。重点介绍了近年来美国开展的水雷改进/研制项目和布雷能力建设情况,包括“快速打击”系列水雷、隐蔽投送水雷、先进水下武器系列、 “锤头”水雷,以及无人布雷平台等。总结了未来美国水雷作战能力,分析了美国水雷作战能力发展的特点, 提出了美国水雷发展对我们的启示。     

Experimental study of three-dimensional breaking wave kinematics

Particle image velocimetry has been used to examine three-dimensional breaking wave kinematics. Two cases of wave breaking were studied. In the first case, the wave field contains a single frequency with a uniform angular spreading within a given range {{ — , .}}. The wave field of the second case consists of a number of frequencies with a uniform angular spreading applied to each frequency. In both cases, the waves are designed such that the wave energy is focused at a given point. The degree of angular spreading has been found to have great effects on the breaking characteristics and kinematics. Two types of breaker were observed, the first being plunging and the second being spilling. Increasing the angular spreading had the effect of making the velocities within the extreme waves larger. The ratio of the crest velocity to the breaking wave speed was approximately unity under both single and multiple frequency conditions, regardless of the angular spreading.     

L-M优化算法在爆破振动参数预测中的应用

当前,以振动峰值作为单一爆破振动安全指标的回归经验公式,在国内外爆破工程界得到广泛应用.但由于爆破机理和爆破介质环境复杂,影响因素诸多,很难用一个经验公式把这些因素都考虑进去;再加上回归分析方法固有的局限性(要求数据有较好的分布规律和大样本量),经验公式方法进行振动预测的效果不甚理想(李保珍,1997;陈寿如,2001;张继春,2001).     

ASOM系统实际应用存在的问题与处理

通过分析ASOM系统在实际应用中发现的问题,分析系统功能存在的欠缺或漏洞,并提出解决方法:做好自动站本身的监控软件和业务软件的监控,应用人工或其它业务软件快速审核地温,业务转型中新业务软件的监控要点。在仪器故障时按照ASOM业务流程做好仪器故障处理及上报工作。     

宁芜地区娘娘山组火山岩Rb-Sr同位素定年及其意义

应用Rb-Sr同位素体系对宁芜盆地娘娘山组火山岩进行年代学分析,样品的全岩—钾长石—斜长石—黑云母的Rb-Sr同位素比值拟合成良好的直线,矿物内部等时线年龄为133.1±3.2 Ma（MSWD=0.096）,代表了娘娘山组火山岩的形成年龄,该年龄值与下伏的龙王山组、大王山组火山岩的形成年龄相近。年代学对比表明,庐枞盆地和宁芜盆地火山岩是集中在130 Ma前后较短的时间范围内形成的,指示了长江中下游地区在130 Ma左右可能处于拉张的峰期阶段。     

山东胶州大西庄辉石巨晶Sr-Nd同位素组成及其源区性质

胶州大西庄玄武岩（73 Ma）中的辉石巨晶与寄主玄武岩具有几乎完全相同的同位素组成,其⁸⁷Sr/⁸⁶Sr（t）和ε_Nd（t）分别为0.703 3～0.704 1、+4.5～+6.5和0.703 5～0.703 8、+7.1～+7.6,暗示辉石巨晶和寄主岩具有相同的地幔源区,即辉石巨晶是玄武岩浆在高压下结晶的产物.亏损的同位素特征表明：在白垩世末期（～73 Ma）,胶东地区的岩石圈地幔已经由富集转变为亏损,表现出类似于中国东部新生代地幔的同位素特征,即表明当时岩石圈减薄（或置换）已经完成.     

基于空间数据挖掘的遥感图像处理

数据与数据库的爆炸式增长导致了一个十分突出的问题,即如何高效、智能地从巨量的、有噪音的、随机的数据中提取有效的、潜在有用的信息和知识.近几年来,空间数据挖掘技术的广泛研究正是基于此目的.本文初步探讨了空间数据挖掘技术在遥感图像处理中的应用,其重点阐述了关联规则,以及数据挖掘技术在遥感图像数据处理中的基本方法以及如何对遥感图像数据进行离散化处理.文章最后简要介绍了遥感图像处理的决策树和人工神经网络数据挖掘技术方法.     

台湾现代主义诗歌的西化和民族化——以纪弦、余光中、洛夫为中心

在台湾现代主义诗歌发展进程中,"现代与传统"、"西方与东方"、"西化与民族化"始终是齐头并进交织在一起的,是一个冲突博弈互补的过程,只是不同时期强调的重点不同而已,不能简单地看作是"全盘西化"或"先西化后回归"。文章以纪弦、余光中、洛夫为中心,通过分析他们的诗歌观念和创作实践,深入透析台湾现代主义诗歌的西化倾向和民族意识。     

贺兰山油松生长的气候响应机制初步探讨

应用VaganovShashkin模型对贺兰山油松的生长变化作了拟合,发现4～8月的降水量大小决定了该年树木生长的宽度变化,另外,除5月外的1～8月份温度和树木生长的负相关是因为较高的温度不利于土壤中水分的保持,间接地导致树木生长的减慢。VS模型在贺兰山地区取得了良好的拟合效果,更为符合树木生长的生理学意义。通过拟合序列和3个采样点树轮宽度序列的对比发现,拟合序列代表着一个较大范围树轮宽窄的变化。坡向对树木生长的影响较大,甚至超过了海拔高度和距离的影响,故建议树木年轮气候学采样应沿着同一坡向采样。     

Average temperature calculation for straight single-row-piped frozen soil wall

The average temperature of frozen soil wall is an essential parameter in the process of design, construction, and safety management of artificial ground freezing engineering. It is the basis of calculating frozen soil’s mechanical parameters, further prediction of bearing capacity and, ultimately, safety evaluation of the frozen soil wall. Regarding the average temperature of single-row-piped frozen soil wall, this paper summarizes several current calculation methods and their shortcomings. Furthermore, on the basis of Bakholdin’s analytical solution for the temperature field under straight single-row-piped freezing, two new calculation models, namely, the equivalent trapezoid model and the equivalent triangle model, are proposed. These two approaches are used to calculate the average temperature of a certain cross section which indicates the condition of the whole frozen soil wall. Considering the possible parameter range according to the freezing pipe layout that might be applied in actual construction, this paper compares the average temperatures of frozen soil walls obtained by the equivalent trapezoid method and the equivalent triangle method with that obtained by numerical integration of Bakholdin’s analytical solution. The results show that the discrepancies are extremely small and these two new approaches are better than currently prevailing methods. However, the equivalent triangle method boasts higher accuracy and a simpler formula compared with the equivalent trapezoid method.