张力腿平台筋腱支撑浮筒结构设计研究     

王火平  金文学  吕东  范志峰  王立权 《海洋工程》2018,36(3):69-75

在张力腿平台筋腱与海底桩基连接后,需要筋腱支撑浮筒为筋腱提供足够的浮力,保证筋腱在平台运抵工作海域之前不会发生倾覆。针对南海油田自主研发的张力腿平台筋腱实际尺寸及设计要求,设计了适用于1 061 mm(40英寸)筋腱、500米水深的张力腿平台筋腱支撑浮筒,并对筋腱支撑浮筒主要受力进行了分析计算,根据所计算的载荷情况对关键部件进行了有限元仿真分析,验证了结构强度的可靠性,并得到了结构的应力集中点与最大变形点,为筋腱支撑浮筒的结构设计提供了参考。  相似文献   

捷联式航空重力扰动矢量解算及误差补偿     

郭栋  孙中苗  吴富梅  张琪 《大地测量与地球动力学》2018,38(12):1295-1301

介绍捷联式航空重力矢量测量的基本原理，利用波数相关滤波（WCF）、比力线性校正的方法对重力扰动的水平和垂向分量进行误差补偿，评定内符合精度。对国产捷联式航空重力矢量仪的某次试验数据进行处理，以验证和评估航空重力矢量仪的性能。结果表明，在半波长分辨率为7.5 km时，6条重复测线的重力扰动水平分量经波数相关滤波处理后，东、北向分量的平均内符合精度分别从9.77 mGal、9.18 mGal提高到5.95 mGal、3.83 mGal；对比力的垂向分量线性校正后，将解算的重力扰动垂向分量再用WCF方法处理，其平均内符合精度从1.27 mGal提高到0.59 mGal。  相似文献   

Stokes漂流对全球海表面温度模拟的影响     

肖林  史剑  蒋国荣  刘子龙  张成成 《海洋通报》2018,(1):55-87

Stokes漂流对海洋上混合层中的流场和温度场结构具有不可忽视的作用。本文基于WAVEWATCHⅢ海浪模式模拟的海浪要素计算得到Stokes漂流,将其引入SBPOM模式的动量方程中,从体积输运的角度研究Stokes漂流对全球海表面温度的影响。分析发现Stokes漂流与Stokes输运在全球呈现高纬度强于中低纬度的带状分布特征,且这种流动与输运对全球海表面温度具有降温作用,该降温作用的分布与全球Stokes输运强度相对应,高纬降温作用大于中低纬度,特别是南极绕极流海域平均降温明显大于其余海域,最大降温可达1.5℃,且全球月平均降温超过0.1℃。  相似文献   

海底管线冲刷悬空及其抑制技术研究综述     

杨少鹏  拾兵 《海洋科学》2018,42(3):121-130

海底管线作为海洋工程的重要组成部分,其安全性受到广泛关注。本文简单回顾了国内外学者通过物理实验、理论分析与数值模拟等方法研究海底管线冲刷悬空及防护问题的成果,并对工程中应用较广泛的防护方法的优缺点进行了简单对比,为该领域的进一步研究提供参考。  相似文献   

Degradation of Atenolol with Electrochemical Oxidation at Mixed Metal Oxide Electrodes Assisted by UV Photolysis          下载免费PDF全文

Shumin Zhu  Bingzhi Dong  Shiqing Zhou 《洁净——土壤、空气、水》2018,46(4)

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Strength Analysis on Brace Structure for Semi-Submersible in Consideration of Wave Slamming     

Fa-li Huo  Zhi Yao  Jian Zhang  Jun-wei Wang  Bin Dong 《中国海洋工程》2018,32(5):536-545

Slamming on bracings of column stabilized units shall be considered as a possible limiting criterion under transit condition based on the requirements in DNV-OS-C103. However, the wave slamming loads under survival condition were ignored for the strength analysis of the brace structures in many semi-submersible projects. In this paper, a method of strength analysis of brace structure is proposed based on the reconstruction and extrapolation of numerical model. The full-scale mooring system, the wind, wave and current loads can be considered simultaneously. Firstly, the model tests of the semi-submersible platform in wind tunnel and wave tanker have been carried out. Secondly, the numerical models of the platform are reconstructed and extrapolated based on the results of model tests. Then, a nonlinear numerical analysis has been conducted to study the wave slamming load on brace in semi-submersible platform through the reconstructed and extrapolated numerical model. For the randomness of wave load, ten subcases under each condition have been carried out. The value of the 90% Gumble distribution values of the ten subcases are used. Finally, the strength on brace structure has been analyzed considering the wave slamming. The wave slamming loads have been compared between the survival condition and transit condition with the method. The results indicate that wave slamming under survival condition is more critical than that under transit condition. Meanwhile, the wave slamming is significant to the structural strength of the brace. It should be overall considered in the strength analysis of the brace structure.  相似文献   

Multiple evidences indicate no relationship between prehistoric disasters in Lajia site and outburst flood in upper Yellow River valley,China   总被引：1，自引：0，他引：1  

GuangHui Dong  FanYu Zhang  FengWen Liu  DongJu Zhang  AiFeng Zhou  YiShi Yang  GongHui Wang 《中国科学:地球科学(英文版)》2018,61(4):441-449

All around the world, ancient legends exist about the Great Flood, and the influence of the Great Flood in human evolutionary history is a hotly debated topic. In China, the legend of the prehistoric Great Flood and Yu the Great’s flood control has a long history and is considered to be closely linked to the establishment of the Xia Dynasty. However, there is a lack of solid scientific evidence. Against this issue, some scholars have proposed that an earthquake around 1920 BCE in the Guanting Basin along the upper reaches of the Yellow River led to the creation of a lake by damming in the Jishi Gorge and that the outburst of water from that lake led to the massive flood in the Yellow River region. These studies provided new scientific evidence for the Chinese legend. In this paper, we date skeletal samples embedded in earthquake sand blasting from the Lajia site, analyze remains from natural disasters (such as earthquakes and floods) and also archaeological remains. In addition, we compared the skeletal samples dating with that of sediments from the dammed-up lake. Our results are inconsistent with those of previous scholars. The earthquake at the Lajia site occurred no earlier than 1800 BCE, and the dammed-up lake in Jishi Gorge had disappeared by 3600 BCE. Thus, the formation and outburst of the dammed lake, the sudden death of ancient humans at the Lajia site and the ancient earthquake were independent events occurring at different times. In addition, the massive flood in the upper reaches of the Yellow River did not actually happen. Thus, we argue against and invalidate the hypothesis that the massive flood was related to Yu the Great’s flood control and the establishment of the Xia Dynasty.  相似文献   

On the intrinsic shape of the gamma-ray spectrum for Fermi blazars     

Shi-Ju Kang  Qingwen Wu  Yong-Gang Zheng  Yue Yin  Jia-Li Song  Hang Zou  Jian-Chao Feng  Ai-Jun Dong  Zhong-Zu Wu  Zhi-Bin Zhang  Lin-Hui Wu 《天文和天体物理学研究(英文版)》2018,(5)

The curvature of the γ-ray spectrum in blazars may reflect the intrinsic distribution of emitting electrons, which will further give some information on the possible acceleration and cooling processes in the emitting region. The γ-ray spectra of Fermi blazars are normally fitted either by a single power-law(PL) or a log-normal(call Logarithmic Parabola, LP) form. The possible reason for this difference is not clear. We statistically explore this issue based on the different observational properties of 1419 Fermi blazars in the 3 LAC Clean Sample. We find that the γ-ray flux(100 Me V–100 Ge V) and variability index follow bimodal distributions for PL and LP blazars, where the γ-ray flux and variability index show a positive correlation. However, the distributions of γ-ray luminosity and redshift follow a unimodal distribution. Our results suggest that the bimodal distribution of γ-ray fluxes for LP and PL blazars may not be intrinsic and all blazars may have an intrinsically curved γ-ray spectrum, and the PL spectrum is just caused by the fitting effect due to less photons.  相似文献   

Sensitive and rapid detection of two toxic microalgae Alexandrium by loop-mediated isothermal amplification     

ZHANG Fengying  SHI Yanhong  JIANG Keji  XU Zhaoli  MA Lingbo 《海洋学报(英文版)》2018,37(2):139-146

A loop-mediated isothermal amplification (LAMP) assay was designed and evaluated for rapid detection of the toxic microalgae Alexandrium catenella and A. minutum, which can produce paralytic shellfish poisoning (PSP). Two sets of four specific primers targeting these two species were derived from the sequence of internal transcribed spacer (ITS) of ribosomal DNA. The method worked well in less than an hour under isothermal conditions of 65℃. LAMP specificity was validated in closely related algae as a comparison, suggesting the strict specificity of the LAMP primers. Two visual inspection approaches were feasible to interpret the positive or negative results. The detection limits of A. catenella and A. minutum samples using the LAMP assay were found to be 5.6 and 4.5 pg DNA, respectively. The sensitivity of this LAMP assay was 10 or 100-fold higher than Polymerase Chain Reaction (PCR) method in detecting the two microalgae. These characteristics of species specificity, sensitivity, and rapidity suggest that this method has the potentiality in the monitoring of red tide caused by A. catenella and A. minutum.  相似文献   

营养限制对三种浮游动物的影响   总被引：1，自引：0，他引：1  

陈蕾  李超伦  周孔霖  时永强  刘梦坛 《海洋学报(英文版)》2018,37(4):58-68

Nutrient imbalance—a mismatch in nutrient ratios between the available food supply and the demands of consumers—has the potential to be transported up food chains,exposing zooplankton to nutrient limitations.In this study,the response of Calanus sinicus(copepod),Moina mongolica(cladocera),and Brachionus plicatilis(rotifer) to nutrient-limited(no-limited,P-limited,and N-limited) food were evaluated from the perspective of growth,reproduction,and stoichiometric homoeostasis.The results indicated that the growth of three species was suppressed under nutrient-limited(especially P-limited) conditions.However,the effect of nutrient limitations on their reproduction was species-specific.For C.sinicus,the dietary UFA(unsaturated fatty acid) as a major phospholipid component affected their egg production and total FA supporting energy promoted the hatchability of eggs.Furthermore,excess carbon in the diet promoted egg production but reduced hatching success.For M.mongolica,nutritional(P and UFA) and energy(total FA) support affected their fecundity.B.plicatilis fecundity exhibited the same pattern of growth(no-limitedN-limitedP-limited).In terms of stoichiometric homeostasis,B.plicatilis' s elemental compositions were less likely to be affected by nutrient limitations than M.mongolica.We suggest that the effects of nutrient imbalances could potentially become an evolutionary force affecting ecosystem structure and stability in eutrophic waters.  相似文献