Seasonal change in body length of important small copepods and relationship with environmental factors in Jiaozhou Bay,China

Differences among species in prosome length and in species’ response to environmental factors do exist. Therefore, it is useful to examine prosome length for different copepod species in variable environments. Seasonal variations in prosome length of four small copepods and their copepodite stages in the Jiaozhou Bay were compared and the relative influence of temperature, salinity, and chlorophyll concentration were examined. Two peaks were found in the mean prosome length of Paracalanus parvus (in early winter and May). For Acartia bifilosa, the maximum values of all copepodites occurred mainly from February to April, and decreased to the bottom in July. Prosome length of Acartia pacifica peaked when it first appeared in June, then reached to the minimum in July. Parvocalanus crassirostris only appeared from late summer to autumn and the mean prosome length showed no clear changes. Correlations of adult prosome length with environmental factors were evaluated. For the four species, temperature was negatively correlated to prosome length except for P. crassirostris. But the different species varied markedly in their responds to temperature. A. bifilosa showed a more definite trend of size variation with temperature than P. parvus and A. pacifica. Correlations of prosome length with salinity were significantly positive for almost all the small copepods. The relationship between chlorophyll concentration and prosome length was complicated for these copepods, but for P. parvus, chlorophyll concentration was also an important affecting factor. Furthermore, investigation needs to be done on food quality for some copepod. These results are essential to estimate the biomass and the production, and to understand these small copepods’ population dynamics in this human-affected bay.     

基于神经网络优化算法的海洋动态缓波型立管设计

柔性立管连接海上平台和水下生产系统,缓波型构型可以减轻其受到的顶部张力和疲劳损伤,触地点处系链对于固定水下立管起着重要作用,然而加装系链的缓波型立管系统设计更为复杂。通过缓波型基本理论计算出合理的立管初始状态,之后使用立管分析软件OrcaFlex,在充分考虑环境因素、船体结构、立管材料和线型以及重力块、浮力块、系链等配置参数的情况下,建立缓波型立管系统有限元模型,通过静动态分析验证其满足设定的关于立管构型、张力、弯曲半径,系链张力和FPSO偏移量5个约束条件。结合神经网络优化算法和遗传算法制定出针对文中立管系统的优化算法并通过MATLAB编程将浮力块数量优化至最少,之后基于L-M算法构建神经网络模型,通过迭代训练提升精度,得到最终参数优化结果。通过对比优化前后静动态分析结果可知：优化后浮力块数量大幅减少,立管最大有效张力大幅减小,而悬挂段最低点深度有一定程度的增大,整体构型更趋向于合理的缓波型构型。     

黑龙江饶河枕状玄武岩地质、地球化学特征及其构造属性

为了确定饶河玄武岩的构造属性,在野外地质观察的基础上,对玄武岩进行岩石学研究和地球化学分析。玄武岩具有典型的枕状构造、淬冷边、中空骸晶和鬣刺结构等特征,反映其形成于海底喷发环境。化学分析样品具有高TiO_2、MgO和低Al_2O_3、CaO、P_2O_5、K_2O等特征,富集大离子亲石元素(Rb、Sr和Ba),微量元素蛛网图呈向上隆起形态,稀土元素配分曲线为右倾型(∑LREE/∑HREE为5.8~6.5),无δEu异常(0.92~0.97),表明样品具有洋岛玄武岩特征。主量和微量元素构造环境判别图指示了样品形成于洋岛或板内环境。样品与亚速尔型和夏威夷型洋岛玄武岩地球化学特征对比,表现出明显的夏威夷型洋岛玄武岩特征。岩石源区分析揭示出岩浆具有地幔热柱起源,并有先期交代地幔熔体的混入,岩浆源区还受壳幔循环的影响。研究表明,饶河枕状玄武岩为夏威夷型洋岛玄武岩,形成于洋壳消减阶段的洋中脊轴外板内喷发环境,为饶河地区存在成熟的洋盆提供直接证据。结合区域研究成果,认为饶河地区经历了古太平洋板块的扩张、洋中脊轴外板内地幔柱上涌、洋壳俯冲消减以及向佳木斯地块仰冲增生的构造演化过程。     

温度、饵料种类对中华哲水蚤(Calanus sinicus)油脂积累与生长发育的影响

中华哲水蚤(Calanus sinicus)C5期幼体的油脂积累是种群在黄海冷水团中得以顺利度夏的关键过程。本研究对温度(10°C和19°C恒温,10—19°CⅠ和10—19°CⅡ变温)与饵料种类(硅藻饵料,自然饵料)双因子培养实验进行研究,探讨温度和饵料种类对中华哲水蚤油脂积累与生长发育的影响作用。结果表明,不同的温度和饵料种类对C5期幼体的油脂积累均有影响。C5期幼体在变温组的油脂积累是10°C组的31%—102%,是19°C组的1.8—6.1倍,低温有利于C5期幼体降低个体代谢消耗以增加油脂的积累。在恒温培养下,C5期幼体在硅藻饵料组的油脂积累是自然饵料组的2.8倍,硅藻饵料比自然饵料更有利于油脂的积累。雌体的体长和油囊体积均随着温度的升高而减小。与硅藻饵料相比,在自然饵料组中雌体的性腺发育速度更快,性腺成熟度更高(繁殖指数:58%—65%)。     

Autonomic visiting in digital 3D scenes

Human-machine interactive visiting and fixed-route visiting are currently the main roaming modes in digital three-dimensional (3D) scenes. However, in general, when a person visits an attraction area, s/he does not follow a fixed path, but instead wander about according to his/her interests. Here, we propose a new roaming mode, called autonomic visiting. That is, in a digital 3D scene, a user selects several interest spots, then a route connecting these spots can be automatically determined and 3D scene can be seen along this route. This study presents a technical approach that enables the realization of autonomic visiting in 3D scenes. Firstly, Delaunay triangular meshes for the terrain in 3D scene are established. Secondly, a plane-growth algorithm and a line-connection algorithm are introduced to automatically mend the broken parts of these triangular meshes. Thirdly, the triangular meshes are then merged and differently weighted according to different layers. Finally, a progress-zone transmission algorithm is presented to optimal the shortest route, which is derived from A-Star (A*) algorithm. Digital 3D campus of Nanjing University, China, is taken as the experimental materials. The experimental results prove the effect of the proposed approach.     

Experimental and numerical investigation on coal drawing from thick steep seam with longwall top coal caving mining

Steep coal seam mining activities will frequently occur during the next few decades in China. In this study, both experimental and numerical methods are employed to investigate the coal drawing from thick steep seam with longwall top coal caving mining. A series of analyses is performed to investigate the features of the drawing body, the distribution of top coal recovery ratio and the shape of the rock flow under steep conditions. The results indicate that the drawing body of top coal develops prior to upper side of the panel face obviously, and the top coal in the central part of the panel has a higher recovery ratio than that in the lower and upper parts in steep coal seam with caving mining method. The flow paths of the fragmented top coal are nearly straight lines moving towards the drawing window, and the fastest path maintains a constant angle with the plumb line. The spatial shape of the rock flow indicates “bidirectional asymmetry,” which results from the presence of the shield beam and dip angle of the coal seam; thus, this is the root cause of the appearance of the drawing body’s prior development towards the upper side of the panel. The field observation data indicates the same distribution of top coal recovery as that in the physical experiment and numerical simulation. Furthermore, suggested measurements are proposed to improve top coal recovery in steep seam mining based on the engineering practice of Dayuan coal mine.     

Accelerating consolidation of soft ground by aerosol injection technique: a field study

We present an aerosol injection technique (AIT) to accelerate the consolidation of soft soils for ground improvement. We employ high-pressure aerosol injections at different depths to enhance the drainage in soft soils for faster consolidation. The technique is briefly described. A well-instrumented field test is carried out to demonstrate its performance. Compared to the traditional methods, our approach gives rise to faster dissipation of excess pore pressure and larger ground settlement. This method is particularly attractive for the improvement in soft ground in medium depths.

     

地震前兆数据监视与管理系统

在北京十三陵地震台建设了一个高度集成的地震观测监控系统, 将原来分散的观测项目(如测震、 GPS、 气氡、 气汞、 电磁波、 地电场等测项), 改造为集中到一台服务器管理, 在一个监控平台上统一实现了对台站数据的收集、 入库、 管理、 处理、 监控等业务; 对这些观测项目可以在控制台上直接取数并将数据入库; 初步实现了观测数据的收集、 数据处理、 数据管理、 数据监控的软件管理系统, 减少了系统维护工作量, 方便台站工作人员操控。 监控系统的地震前兆数据监管软件系统DataMonitor可准实时监视数据, 检查数据的异常和到达情况, 并向台站数据管理人员告警; 可对数据库数据进行统计, 包括数据到达情况统计、 缺数统计、 数据连续率统计等, 并可按用户定制的测项分类进行统计。 该系统还提供多种前兆数据处理方法, 实现对前兆数据的各种常规分析处理。 地震前兆数据监视与管理系统已在北京十三陵地震台应用, 满足了数据管理人员日常工作需要, 可及时方便地掌握数据的情况并对观测系统进行维护。