光照、温度对黑鲷(♀)×真鲷(♂)杂交子代受精卵孵化效果的影响     

刘海林  张志勇  张志伟  许津  陈淑吟  贾超峰  祝斐  孟乾 《海洋科学》2018,42(5):108-115

为了研究不同光照强度、温度对黑鲷(Acantho pagrusschlegelii)(♀)×真鲷(Pagrosomus major)(♂)杂交F1代受精卵孵化效果及仔鱼存活的影响,作者采用试验生态学的方法比较不同温度(16、18、20、22、24、26℃)下杂交鲷受精卵的孵化率、畸形率、孵化时间、7日龄仔鱼的存活率;比较不同光照强度下(10、100、300、800、1500、4 000、10 000 lx)受精卵孵化率、畸形率、孵化时间;比较不同光照强度下(200、1 000、2 000、5 000、10 000、15 000、20 000 lx)7日龄仔鱼的存活率。结果表明:在盐度为22条件下,受精卵最高孵化率(34.00%)和最低畸形率(16.65%)的孵化温度为20℃;在16～26℃范围内,温度与孵化时间呈负相关,与7日龄仔鱼存活率也呈负相关。不同的光照强度对受精卵孵化率和孵化时间的影响不显著,孵化率为65.88%～71.88%;但大于800lx的光照会令畸形率上升(大于15.21%);另外,5000～10000lx的光照强度更适宜仔鱼生存,7日龄仔鱼存活率达到38%～40.75%。黑鲷(♀)×真鲷(♂)杂交子代最佳孵化温度为20℃,最适光照强度为5 000～10 000 lx。  相似文献   

基于印度洋海温信号的我国西北地区东部夏季降水组合降尺度预测方法研究     

朱晓炜  李清泉  孙银川  王璠  王岱  高睿娜  刘颖 《气象》2024,50(3):357-369

利用国家气候中心第二代气候模式预测业务系统(BCC-CPSv2)预测产品,引入印度洋海温信号,采用组合降尺度方法建立了西北地区东部汛期降水预测模型。该预测模型对1991—2017年西北地区东部夏季降水的回报技巧较BCC-CPSv2预测技巧显著提高,空间相关系数由0.42提高到0.75,均方根误差明显减小,最多下降达80%。预测模型对降水空间分布型的预测能力较好,很好地回报了典型年份（1987年和2010年）夏季的降水距平百分率分布。通过抓住气象变量的空间分布特征,组合降尺度方法可以修正动力模式产品的预测误差,为西北地区东部夏季降水预测提供科学依据和技术支持,具有较好的应用前景。  相似文献   

基于Hybrid模式精细化移动气象服务系统的设计与实现     

任广治  宋萍  徐彩艳  朱学伟  杨秋彦  张孝峰 《气象科技》2022,50(4):594-599

近年来移动气象服务需求快速增长,而气象信息的辅助决策功能在现代气象服务体系中的作用越发凸显,如何快速建立一个性能可靠、易于扩展、自主可控的移动气象服务系统成为当前各级气象部门重点关注内容之一。本文介绍了基于Hybrid模式构建精细化移动气象服务系统的总体设计,并通过Hybrid、插件化开发、MVC框架、HTML5融合等关键技术实现了气象信息在移动端的展示交互,体现了Hybrid开发模式在功能复用性高、迭代升级方便等方面的技术优势。经过近5年的持续迭代升级,目前系统产品已经广泛应用在山东省各级气象部门、政府决策部门以及重点服务行业中,在气象服务社会防灾减灾过程中发挥出重要作用。  相似文献   

全球月平均高度距平场正斜压性的分析(Ⅱ)——与遥相关型的联系          下载免费PDF全文

张邦林  刘洁 《大气科学学报》1993,16(4):439-445

利用欧洲中心全球客观分析的7层月平均位势高度距平资料,计算了几种大气环流遥相关型指数与各层位势高度距平的相关系数分布。发现:大气环流异常的正压、斜压性的地理差异与遥相关型的垂直结构关系密切。综合经验正交函数分析,结果亦然。  相似文献   

台湾费丛峡谷对强地面运动的影响研究──利用单台资料及2．5维SH混合方法     

温联星  姚振兴 《地球物理学报》1995,38(1):64-70

本文通过格林函数反褶积方法，由台湾峡谷附近的记录资料预测峡谷区的强地面运动的时程曲线．峡谷区的理论格林函数应用２．５维ＳＨ混合方法求解．通过格林函数反褶积方法得到的峡谷区费丛１及费丛２台的位移、速度、加速度和实际资料对比，取得了满意结果．计算结果表明，峡谷底部的峰值加速度相对峡谷边缘为最小；在靠近震中的一侧，峡谷的加速度的最大振幅相对比另一侧大．还给出了其余３个台的预测结果，研究了它们的加速度傅里叶谱和反应谱．  相似文献   

Equivalent force control method for generalized real‐time substructure testing with implicit integration     

Bin Wu  Qianying Wang  P. Benson Shing  Jinping Ou 《地震工程与结构动力学》2007,36(9):1127-1149

This paper presents a new method, called the equivalent force control method, for solving the nonlinear equations of motion in a real‐time substructure test using an implicit time integration algorithm. The method replaces the numerical iteration in implicit integration with a force‐feedback control loop, while displacement control is retained to control the motion of an actuator. The method is formulated in such a way that it represents a unified approach that also encompasses the effective force test method. The accuracy and effectiveness of the method have been demonstrated with numerical simulations of real‐time substructure tests with physical substructures represented by spring and damper elements, respectively. The method has also been validated with actual tests in which a Magnetorheological damper was used as the physical substructure. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Towards error‐free hybrid simulation using mixed variables     

Tarek Elkhoraibi  Khalid M. Mosalam 《地震工程与结构动力学》2007,36(11):1497-1522

Two procedures are developed and implemented in a hybrid simulation system (HSS) with the aim of enhancing the accuracy and reliability of the online, i.e. pseudo‐dynamic, test results. The first procedure aims at correcting the experimental systematic error in executing the displacement command signal. The error is calculated as the difference between command and feedback signals and correlated to the actuator velocity using the least‐squares method. A feed‐forward error compensation scheme is devised leading to a more accurate execution of the test. The second procedure employs mixed variables with mode switching between displacement and force controls. The newly derived force control algorithm is evaluated using a parametric study to assess its stability and accuracy. The implementation of the mixed variables procedure is designed to adopt force control for high stiffness states of the structural response and displacement control otherwise, where the resolution of the involved instruments may favour this type of mixed control. A simple pseudo‐dynamic experiment of steel cantilever members is used to validate the HSS. Moreover, two experiments as application examples for the two developed procedures are presented. The two experiments focus on the seismic response of (a) timber shear walls and (b) reinforced concrete frames with and without unreinforced masonry infill wall. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Stability and accuracy analysis of outer loop dynamics in real‐time pseudodynamic testing of SDOF systems     

Oya Mercan  James M. Ricles 《地震工程与结构动力学》2007,36(11):1523-1543

Real‐time pseudodynamic (PSD) testing is an experimental technique for evaluating the dynamic behaviour of a complex structure. During the test, when the targeted command displacements are not achieved by the test structure, or a delay in the measured restoring forces from the test structure exists, the reliability of the testing method is impaired. The stability and accuracy of real‐time PSD testing in the presence of amplitude error and a time delay in the restoring force is presented. Systems consisting of an elastic single degree of freedom (SDOF) structure with load‐rate independent and dependent restoring forces are considered. Bode plots are used to assess the effects of amplitude error and a time delay on the steady‐state accuracy of the system. A method called the pseudodelay technique is used to derive the exact solution to the delay differential equation for the critical time delay that causes instability of the system. The solution is expressed in terms of the test structure parameters (mass, damping, stiffness). An error in the restoring force amplitude is shown to degrade the accuracy of a real‐time PSD test but not destabilize the system, while a time delay can lead to instability. Example calculations are performed for determining the critical time delay, and numerical simulations with both a constant delay and variable delay in the restoring force are shown to agree well with the stability limit for the system based on the critical time delay solution. The simulation models are also used to investigate the effects of a time delay in the PSD test of an inelastic SDOF system. The effect of energy dissipation in an inelastic structure increases the limit for the critical time delay, due to the energy removed from the system by the energy dissipation. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

广西两系杂交稻制种安全期气候分析   总被引：1，自引：0，他引：1  

涂方旭  李雄 《气象研究与应用》2001,22(4):40-43

根据两系杂交水稻制种对气象条件的要求 ,利用广西 80多站的气象资料 ,统计分析了广西各地两系杂交水稻制种的安全期 ,提出了广西杂交水稻安全制种应注意的一些气候问题  相似文献   

A hybrid analysis method for linear dynamic soil-structure interaction in time and frequency domain     

丁海平  廖振鹏 《地震学报(英文版)》2001,14(4):440-447

IntroductionThe analysis of dynamic soil-structure interaction for important engineering project is still based on linear model (including equivalent linear model) with complex damping, and traditional frequency domain method (Lysmer, et al, 1975, 1981; DING, et al, 1999). Namely, first calculating frequency domain solution by Fourier transform, and then calculating time domain solution by Fourier inverse transform. The motion equation of a system in frequency domain is usually written as (…  相似文献