径向基神经网络在沉降预测中的应用

针对大型建筑物的沉降监测存在较多的不等时间间隔沉降监测数据,现有模型需要对此类数据进行等间隔处理后建立沉降预测模型的现状,该文采用无需对监测数据进行等间隔预处理的径向基神经网络对沉降监测数据建立沉降预测。通过对西安某大厦基坑开挖对地表和周围建筑物影响的沉降监测数据进行实例分析,并与非等间隔灰色GM(1,1)预测模型进行对比,利用模型评价指标评价预测模型精度。结果表明:采用径向基神经网络建立预测模型处理过程简便,其预测精度优于非等间隔灰色GM(1,1)预测模型。     

Spatio-Temporal Characteristics of Heavy Precipitation Forecasts fromECMWF in Eastern China

This study examines the spatio-temporal characteristics of heavy precipitation forecasts in eastern China fromthe European Centre for Medium-Range Weather Forecasts (ECMWF) using the time-domain version of the Method forObject-based Diagnostic Evaluation (MODE-TD). A total of 23 heavy rainfall cases occurring between 2018 and 2021 areselected for analysis. Using Typhoon “Rumbia” as a case study, the paper illustrates how the MODE-TD method assessesthe overall simulation capability of models for the life history of precipitation systems. The results of multiple tests withdifferent parameter configurations reveal that the model underestimates the number of objects’ forecasted precipitationtracks, particularly at smaller radii. Additionally, the analysis based on centroid offset and area ratio tests for differentclassified precipitation objects indicates that the model performs better in predicting large-area, fast-moving, and long lifespan precipitation objects. Conversely, it tends to have less accurate predictions for small-area, slow-moving, and short lifespan precipitation objects. In terms of temporal characteristics, the model overestimates the forecasted movement speedfor precipitation objects with small-area, slow movement, or both long and short lifespans while underestimating it forprecipitation with fast movement. In terms of temporal characteristics, the model tends to overestimate the forecastedmovement speed for precipitation objects with small-area, slow movement, or both long and short lifespans while un derestimating it for precipitation with fast movement. Overall, the model provides more accurate predictions for theduration and dissipation of precipitation objects with large-area or long-lifespan (such as typhoon precipitation) whilehaving large prediction errors for precipitation objects with small-area or short-lifespan. Furthermore, the model’s simu lation results regarding the generation of precipitation objects show that it performs relatively well in simulating thegeneration of large-area and fast-moving precipitation objects. However, there are significant differences in the forecastedgeneration of small-area and slow-moving precipitation objects after 9 hours.     

饲料中添加植酸酶和非淀粉多糖酶对大黄鱼生长和消化酶活性的影响

以初始体重(1.88±0.01)g的大黄鱼(Poseudosciaena croceaR.)为研究对象,探讨饲料中添加植酸酶和非淀粉多糖酶对大黄鱼生长、体组成以及消化酶活性的影响。实验结果表明,饲料中添加植酸酶和非淀粉多糖酶对大黄鱼的成活率无显著影响,但却显著提高了大黄鱼的特定生长率(p<0.01)。饲料中添加非淀粉多糖酶对大黄鱼鱼体水分、粗蛋白、粗脂肪和灰分含量及身体总能均无显著影响。饲料中添加植酸酶对大黄鱼鱼体水分、粗蛋白和粗脂肪含量及身体总能也无显著影响,但却显著提高了鱼体的灰分含量(p<0.05)。饲料中添加非淀粉多糖酶和植酸酶后,大黄鱼胃和肠道蛋白酶和淀粉酶活性均有上升趋势,并且添加非淀粉多糖酶能显著提高大黄鱼胃和肠道淀粉酶活性,添加植酸酶能显著提高大黄鱼胃和肠道蛋白酶活性(p<0.05)。然而,大黄鱼胃和肠道脂肪酶活性并没有受到2种酶制剂添加的显著影响。     

海洋桡足类氨基酸组成及与饵料和光照的关系

桡足类氨基酸含量受其饵料浮游植物的影响。同一种桡足类因采集地不同，氨基酸的总量也不相同；19种氨基酸重量百分比随不同桡足类而异，但是不同桡足类各种氨基酸占总氨基酸的比例除胱氨酸和牛磺酸的变化比较大以外，其它都基本相同；胱氨酸和牛磺酸的变化与总氨基酸不成正比。各海区不同植食性桡足类的氨基酸组成和海区浮游植物氨基酸的组成有着很好的相关性，相关系数R^2在0．85以上。桡足类胱氨酸占总氨基酸的比例与采样站海水1％光衰减深度有很好的相关关系，其回归方程为y=0．28091nx 0．131，R^2=0．6427，n=13；随海水1％光衰减深度的增加，胱氨酸的含量以对数形式递增。桡足类氨基酸与UV的关系有待进一步研究。     

桶形基础平台海上沉放安装

桶形基础平台是世界上一种最新型的海洋平台，可广泛应用于海上油气田开发。为满足我国际油气田开发中卫星平台的结构和功能要求，桶形基础平台采用新的压载沉放方法安装，具有更高的效率和经济性。沉放过程中桶形基础平台受到水流和波浪的作用，结合模型试验对平台运动进行数值模拟分析，以了解在整个沉放过程中相应参数的变化趋势。根据桶形基础平台的特征，制定联台沉放方案，并通过压载实现平台的沉放控制。     

码头系泊船舶模型试验

通过对一艘50kDWG码头系泊船舶的模型试验，得出了系泊缆绳张力随外载荷变化的一般规律，对码头系泊有一定的参考价值。     

中国和越南青蟹线粒体16S rRNA基因序列分析

为确定我国青蟹的分类地位及其资源的合理利用与保护提供理论依据，对中国和越南青蟹的线粒体16S rRNA基因片段序列进行了测定，并同Genbank中其他青蟹的序列进行了比较，分析研究了青蟹种内和种间的遗传差异及其分类地位。结果显示：中、越青蟹个体间序列差异极小，与Genbank中Scylla paramamosain同源片段序列的相似性达到99％以上．而与其他3种青蟹的差异达3．91％～8．41％。所得序列与S．paramamosain，S．serrata，S．olivacea及s．tranquebarica的遗传距离分别为0．002，0．075，0．087，0．042，种间遗传距离远大于种内距离。序列特征、遗传距离和系统进化分析结果都表明本文研究的中国和越南青蟹均为S．paramamosain。     

九龙江口及邻近港湾红树林区沉积物中多环芳烃污染现状及评价

本文应用沉积物质量评价基准法对九龙江口及邻近港湾红树林区表层沉积物中多环芳烃的污染现状进行了生态风险评价,并定量分析了多环芳烃的相对污染强度.研究结果表明:各测站区多环芳烃相对污染系数均小于1,范围为0.022~0.620,污染程度尚属较低,引起生物毒性效应的几率相对较小.低分子量多环芳烃芴、萘和二氢苊占总相对污染系数比例较高(平均分别为18.1%、16.7%和15.3%),因而具有相对较高的潜在生态危害风险.     

A Finite Element Solution of Wave Forces on Submerged Horizontal Circular Cylinders

In this paper, a numerical model is established for estimating the wave forces on a submerged horizontal circular cylinder. For predicting the wave motion, a set of two-dimensional Navier-Stokes equations is solved numerically with a finite element method. In order to track the moving non-linear wave surface boundary, the Navier-Stokes equations are discretized in a moving mesh system. After each computational time step, the mesh is modified according to the changed wave surface boundary. In order to stabilize the numerical procedure, a three-step finite element method is applied in the time integration. The water sloshing in a tank and wave propagation over a submerged bar are simulated for the first time to validate the present model. The computational results agree well with the analytical solution and the experimental data.Finally, the model is applied to the simulation of interaction between waves and a submerged horizontal circular cylinder.The effects of the KC number and the cylinder depth on the wave forces are studied.     

对黄海中、古生界地质构造特征及油气远景的新认识

近两年来开展了新一轮大调查，根据长排列多道地震资料显示，北黄海在印支-燕山运动形成的隆起背景下，分布着4个中，新生代拗陷，最大沉积厚度8000m，其中晚侏罗-早白垩世沉积厚度6000m，是拗陷中主要的生储油层，局部构造类型主要为断块，断背斜，潜山及反转背斜等，具有形成中小型油气田的潜力。南黄海是下扬子后加里东台地的主体，于中部隆起及其两侧，广泛分布着厚度大于5000m的较稳定的晚古生代-早中生代海相地层；中生代以来，在中部隆起南侧发育了裂谷型盆地，可与苏北盆地对比；其北侧，则在苏胶造山带与中部隆起之间形成前陆盆地，其面积约4万km^2，古生代及中，新生代沉积厚度可达15000m，具有海相及陆相多层系，多类型的成藏系统，局部构造类型多，晚期成藏条件好，具有形成大中型油气田的潜力。南黄海的“黄北前陆盆地”是本区最有远景的战略勘探区。对中部隆起区，应加强研究，以期在非构造圈闭油气田方面有新的发现。