基于K分布雷达海杂波建模与仿真

海杂波的仿真对杂波环境下弹载雷达检测性能的研究具有重要意义。文章首先建立了海杂波回波模型,其次分别对海杂波后向散射系数、复散射截面积以及起伏调制函数进行了建模分析,最后结合海杂波幅度分布特性和时间相关特性,利用零记忆非线性法对海杂波进行了仿真。结果表明,该方法可以有效地模拟雷达海杂波,从而为雷达信号处理器的设计奠定了基础。     

粗糙海面的电磁散射缩比模拟测量的若干基本问题

针对实验室内难以构造的高海情PM谱海面,采用电磁缩比测量的方法研究其电磁散射特性,首先定量分析了以淡水替代海水造成不满足物理相似性要求而引入的误差,然后讨论了缩比PM谱海面满足几何相似性条件的要求,和对粗糙海面进行缩比模拟测量的途径,根据粗糙海面缩比模拟理论与条件,在实验室内成功模拟构造满足缩比测量理论的粗糙海面。     

无线电脉冲引信海面回波建模及仿真

无线电脉冲引信海面回波建模及仿真是根据无线电脉冲引信的探测特点和海面物理反射特性进行的建模仿真。根据无线电脉冲引信采样量化间隔,划分海面有效照射区域的等距离等值线,并由导弹飞行姿态和引信天线波束宽度确定海面有效照射区的等视线角等值线。再根据等距离等值线和等视线角等值线的交点,计算天线主波束照射面积和天线副瓣照射面积的合成功率,以此得到一个表示海面散射特性的冲击函数,用此函数和输入脉冲信号卷积得到无线电脉冲引信海面回波信号的数学模型,从而为仿真研究脉冲引信低空工作性能提供必须的仿真基础。     

无线电引信距离波门压缩的实现与仿真

为避免防空导弹在拦截超低空飞行目标时无线电引信受海面杂波的干扰,对距离波门压缩的电路实现方式进行研究.分析了距离波门压缩的原理,给出了高度跟踪和波门压缩的实现方式,并在Matlab/Simulink仿真平台下进行仿真验证.结果表明:该方式能准确地实现高度跟踪和距离波门压缩,有效抑制海杂波对无线电引信的干扰.     

海盐场卤水中锂资源状况和产业前景初步探讨

优选渤海湾地区的2个大型海盐生产企业,针对制盐的各工艺流程中Li的含量变化进行研究。研究结果表明：在制盐工艺中,从海水至老卤锂明显逐步浓缩,2个盐场老卤中LiCl浓度分别为9727 mg/L和13815 mg/L,接近卤水锂矿边界品位;海水盐化工生产过程中盐类结晶对Li+的吸附效应不明显。根据我国海盐产量与渤海湾地区的采样数据推算,2013年全国海水盐场全年生产的老卤中锂金属量为45595 t,折合成碳酸锂当量为2 43023 t。由此可见,海盐场年处理海水中锂含量较高,另外含锂的苦卤老卤较易集中,单一提锂工艺具有通用性,因此我国海盐场卤水中锂资源的提取前景广阔。另外,直接从海水中提锂工艺也应是今后的主攻方向,一旦突破技术成本,直接从海水提锂产业化前景无限。     

钢管海砂再生混凝土轴压性能试验与分析

以再生粗骨料取代率和海砂中的Cl-含量为主要参数,完成了18个钢管海砂再生混凝土轴压试验,分析了再生粗骨料取代率、海砂中的Cl-含量对试件破坏特征和受力变形的影响.结果表明:钢管海砂再生混凝土受力过程与普通钢管混凝土相似,包含弹性、弹塑性和破坏3个阶段,其主要破坏模式为斜剪破坏;试件峰值荷载随着再生粗骨料取代率和海砂中的Cl-含量的增加而略有降低;峰值应变随着再生粗骨料取代率的增加而增大,随着Cl-含量的增加先增大后减小.同时,对比分析了不同规范的峰值荷载公式计算值与试验值的差异,并根据试验数据对钢管海砂再生混凝土轴压应力-应变全曲线计算模型进行了拟合.     

Component analysis of some chemical parameters influencing the stability of DDVP in sea‐sediments along the east coast of India

The component analysis of some chemical parameters such as half‐life period, pH, salinity, total organic carbon (TOC), clay mineral concentration (Kaolinite, Illite, Montmorrillonite) and the elemental concentrations (Al, Fe, Ti) showed that only three components collectively retained 98% of variation of the original data. The first component carries maximum co‐variance with salinity and TOC, the second component is due to clay‐montmorrillonite, and the third component is attributed to TOC and Fe. The first component accounted for 69%, the second 28% and the third for 3% of total variation. The impact of TOC on the stability of pesticide, DDVP is much more pronounced by its negative covariance with the half life period as revealed by the first principal component.     

An environmental purpose artificial island off Belgium

Processing municipal and industrial wastes on land and particularly near inhabited centra has met with increased opposition. An apparent remedy to the problem is the establishment of such facilities offshore, hence various projects to build them on artificial islands. The paper examines a concrete proposal to locate such an island offshore from the Belgian Coast. Oceanographic and environmental aspects of the site are discussed, construction methods reviewed, erosion and corrosion effects looked at. The possibility of utilizing ocean power to provide the necessary operation energy is likewise considered.     

Strategies in environmental education

The causes of environmental changes, including climate, are neither fully understood nor identified, nor do scientists agree about their nature. Yet, their impact is such that action cannot be delayed. This involves spreading public awareness through environmental education and sensitization. Hence a need to reach, to educate the poorly informed public at large. With the classroom as the base, “town meetings” and eco‐tourism may constitute potentially useful approaches towards that goal.     

华侨大学厦门校区图书馆中庭夏季室内热环境实测与分析

本文采用自动记录仪,对华侨大学厦门校区图书馆中庭夏季室内热环境实测。根据测得的室内热环境4个参数,结合PMV分析评价华侨大学厦门校区图书馆中庭夏季室内热环境舒适度。主要结论有:(1)华侨大学厦门校区图书馆在开窗和闭窗状态时,中庭温度随着高度的增加而升高;(2)华侨大学厦门校区图书馆在开窗和闭窗时中庭温度差不多,但是开窗时候湿度变化的曲线幅度范围比闭窗的时候大。(3)华侨大学厦门校区图书馆中庭PMV值随着高度的增加而升高,热舒适性随着高度的增加而下降;(4)华侨大学厦门校区图书馆在夏季时不论在开窗还是闭窗状态下,中庭的室内热环境都处于不舒适的范围内。