Effects of temperature and salinity on the development of embryos and larvae of the veined rapa whelk Rapana venosa （Valenciennes, 1846）

The major population of the veined rapa whelk Rapana venosa(Valenciennes, 1846), which is an important fishery resource, is facing a large decline in China. We studied the effects of incubation temperature(16–34℃ at salinity 30) and salinity(5–45 at 25℃) on the incubation period and subsequent larval development. In the temperature experiment, the shortest incubation period was 12 days at 34℃, the lower temperature limit was 16℃, the longest mean shell length(1 193±17 μm) occurred at 25℃ and the highest survival rate 72.28%±5.62% was observed at 28℃. In the salinity experiment, the shortest incubation period was 15 days at 25. The salinity tolerance range was 15–40, the longest mean shell length(855±9 μm) and the highest survival rate 72.93%±4.85% were both observed at 35. This study demonstrated that, during the egg–mass stage, temperature and salinity regimes infl uence later growth and survival of larvae. These observations deepen our understanding of the ecology and conservation of natural populations of Rapana venosa.     

2009—2014年11种大气科学核心期刊来源指标的统计分析

利用2010—2015年版《中国学术期刊影响因子年报（自然科学与工程技术）》提供的可被引文献量等期刊来源指标,对《中文核心期刊要目总览（2014年版）》公布的11种大气科学核心期刊的各项来源指标进行统计分析。结果表明：6年来11种期刊的载文能力没有发生明显的变化;年均可被引文献量为1 326篇,论文发表总页数为11 270,论文篇均长度为8.5页,平均引文数为23篇,基金论文比为0.92。展望未来中文核心期刊的发展方向是：刊期缩短、可被引文献量增多、论文篇均长度增大、平均引文数增加、基金论文比维持在较高水平。     

一种利用扩展磁偏角数据自动计算磁偏角的方法

提出一种基于扫描磁偏角地磁图自动计算磁偏角的方法,把一维磁偏角数据扩展到二维数据,将有关图像校正的方法用在磁偏角的求取上,即在扫描磁偏角地磁图中以图上的地理坐标、扩展磁偏角等值线坐标以及扩展磁偏角等变线坐标所对应的像素坐标为媒介,通过非线性变换,最终建立起地理坐标、磁偏角等值线以及磁偏角等变线之间的相互对应关系,以解决...     

POS技术在平原地区1:10000 DLG生产中的外业控制点布设

POS(DGPS/IMU)技术能够获取航摄瞬间航片外方位元素,采用POS技术进行空三加密和DLG制作,能够节省大量的外业控制点,这对提高航测地形图生产效率,降低成本具有重要意义。本文主要研究POS技术在平原地区1:10 000地形图生产中的外业控制点布设。设计了二十三种外业控制点布设方案,采用集成传感器定向法进行空三加密试验,在实验结果的基础上选择精度符合要求的数据制作了一幅1:10 000DLG,并对其进行精度测试。通过试验和研究,提出了合适的外业控制点布设方案,为POS技术应用于大规模航测4D产品生产做好技术准备。     

CINRAD/SB雷达接收机技术特点及故障诊断方法

介绍了CINRAD/SB雷达接收系统技术特点。根据接收机的主通道、测试通道、故障定位通道的信号流程,从监测信息、报警信息、关键点参数测量入手,总结了CINRAD/SB雷达接收系统故障诊断方法和技巧。详细介绍了利用RDA计算机的报警信息直接查找故障、通道测试法和关键点波形测试法3种诊断故障的方法,并列举了接收机主通道前端、后端以及测试通道3个不同类型的典型故障个例的分析和处理步骤。提出了接收系统维修方面的一些建议,为新一代天气雷达技术支持和保障提供借鉴。     

CINRAD／SA天气雷达软故障个例分析与处理

对北海CINRAD／SA天气雷达的几个典型的软故障进行分析,找出故障发生的原因,并给出了故障处理的方法．     

CINRAD/SB雷达伺服上电故障诊断分析

在详细介绍CINRAD/SB雷达数字伺服系统加电控制、天线状态信号流程的基础上,分析出数字伺服系统无法上电3方面原因：负载过载导致空气开关保护性断电;伺服系统加电信号不正常;制动器过流导致温度超限。总结了CINRAD/SB雷达伺服系统无法上电故障的分析方法和诊断流程。通过诊断流程详细论述两例伺服无法上电的复杂故障分析和排除过程,以及在台站无配件更换情况下,充分利用雷达线路特点暂时采用应急方法尽快恢复雷达运转的方法,保证灾害性天气监测的需求。为新一代天气雷达技术支持和保障提供借鉴。     

长江三角洲近46 a气温和降水的变化趋势

利用长江三角洲地区84个气象站观测数据,分析了长江三角洲1961—2006年气温和降水的时空变化趋势。结果表明,46 a间长江三角洲地区年平均气温上升趋势显著,冬季平均气温的增温幅度最大,春、秋次之。增温显著区域与城市带分布区域吻合。极端最低气温有明显上升,而年极端低温事件日数的下降趋势显著。部分地区的极端最高气温呈上升趋势,在城市密集带尤为突出。年降水量没有明显的变化趋势,但降水的季节分配有所变化,冬、夏季降水量呈现显著上升趋势,秋季降水量明显下降,春季没有明显变化。     

Analytical solution for two-phase flow in a wellbore using the drift-flux model

This paper presents analytical solutions for steady-state, compressible two-phase flow through a wellbore under isothermal conditions using the drift flux conceptual model. Although only applicable to highly idealized systems, the analytical solutions are useful for verifying numerical simulation capabilities that can handle much more complicated systems, and can be used in their own right for gaining insight about two-phase flow processes in wells. The analytical solutions are obtained by solving the mixture momentum equation of steady-state, two-phase flow with an assumption that the two phases are immiscible. These analytical solutions describe the steady-state behavior of two-phase flow in the wellbore, including profiles of phase saturation, phase velocities, and pressure gradients, as affected by the total mass flow rate, phase mass fraction, and drift velocity (i.e., the slip between two phases). Close matching between the analytical solutions and numerical solutions for a hypothetical CO₂ leakage problem as well as to field data from a CO₂ production well indicates that the analytical solution is capable of capturing the major features of steady-state two-phase flow through an open wellbore, and that the related assumptions and simplifications are justified for many actual systems. In addition, we demonstrate the utility of the analytical solution to evaluate how the bottomhole pressure in a well in which CO₂ is leaking upward responds to the mass flow rate of CO₂-water mixture.     

不同量级磁暴对新沂地震台地电阻率的影响

探讨强烈磁暴对新沂地震台地电阻率测最的影响.根据磁暴效应,得出对地电阻率的影响,从而进行不同量级磁暴对江苏省新沂地震台地电阻率的影响分析.同时分析各测向产生的差异性及原因.由于新沂地震台地电阻率测量采用正反向双向供电,磁暴对地电阻率的影响量很小,其形态仍存在同步变化.如果采取减少每次测量的供电时间、供电次数,加大供电电...