渤海湾盆地沙河街组钙质超微化石古生态及沉积环境

渤海湾盆地沙河街组中钙质超微化石的发现,表明这一时期渤海湾盆地与海水有过联系。对钙质超微化石古生态及沉积环境研究表明,化石主要产出时代为始新世晚期至渐新世早中期,属“间冰期”亚热带气候型。这一问题的深入研究,对于渤海湾盆地的石油勘探有重要意义。     

锯缘青蟹胚胎发育过程主要生化组成

锯缘青蟹胚胎３种主要生化组成以蛋白质含量为最高，脂类含量次之，碳水化合物含量最低。胚胎发育的结果导致三种主要生化组成含量降低，其中蛋白质减少了３９．０％，脂类、碳水化合物含量分别减少了１７．０％、７．７％，说明蛋白是青蟹胚胎发育的主要能源物质，这可能与动物适应热带、亚热带的水生环境有关。     

对虾传染性肌肉坏死病研究进展

对虾传染性肌肉坏死病(infectious myonecrosis,IMN)最初于2002年8月爆发于巴西Piaui州的凡纳滨对虾(Litopenaeus vannamei)养殖场,并很快在巴西东北沿岸蔓延开来,目前已传至亚洲.2004年,经美国亚利桑那大学(University of Arizona)水产病害实验室研究,该病为一种新的对虾疾病,根据其症状,暂定名为传染性肌肉坏死病.     

换道概率对交通系统动能的影响

基于跟车模型的特点,提出了跟车模型的动能变化公式,利用该公式研究换道概率对各车辆动能的影响.数值实验结果表明,换道概率和相对速度对各车辆动能产生较大影响,但换道概率和相对速度会分别降低其动能变化频率和幅度.此外,系统增加的平均动能会随着系统最大换道概率的增加而降低.     

Laboratory tests of vortex-induced vibrations of a long flexible riser pipe subjected to uniform flow

Laboratory tests have been conducted on vortex-induced vibration (VIV) of a long flexible riser towed horizontally in a wave basin. The riser model has an external diameter of 16 mm and a total length of 28.0 m giving an aspect ratio of about 1750. Reynolds numbers ranged from about 3000 to 10,000. Fiber optic grating strain gages are adopted to measure the dynamic response in both cross-flow and in-line directions. The cross-flow vibrations were observed to vibrate at modes up to 6 and the in-line reached up to 12. The fundamental response frequencies can be predicted by a Strouhal number of about 0.18. Multi-mode responses and the asymmetry of the bare pipe response in uniform flow were observed and analyzed. The experimental results confirmed that the riser pipe vibrated multi-modally despite it being subject to a uniform current profile and all of the excited modes vibrated at the Strouhal frequency. The asymmetrical distribution of displacement mainly resulted from the modal composition. Higher harmonics of the VIV response such as the third, fourth and fifth harmonics frequencies were found to be steady over the entire duration of the test even if they varied along the length of the riser pipe.     

Tropical cyclones and multiscale climate variability: The active western North Pacific Typhoon season of 2018

The 2018 typhoon season in the western North Pacific(WNP) was highly active, with 26 named tropical cyclones(TCs) from June to November, which exceeded the climatological mean(22) and was the second busiest season over the past twenty years. More TCs formed in the eastern region of the WNP and the northern region of the South China Sea(SCS). More TCs took the northeast quadrant in the WNP, recurving from northwestward to northward and causing heavy damages in China's Mainland(69.73 billion yuan) in 2018. Multiscale climate variability is conducive to an active season via an enhanced monsoon trough and a weakened subtropical high in the WNP. The large-scale backgrounds in 2018 showed a favorable environment for TCs established by a developing central Pacific(CP) El Ni?o and positive Pacific meridional mode(PMM)episode on interannual timescales. The tropical central Pacific(TCP) SST forcing exhibits primary control on TCs in the WNP and large-scale circulations, which are insensitive to the PMM. During CP El Ni?o years, anomalous convection associated with the TCP warming leads to significantly increased anomalous cyclonic circulation in the WNP because of a Gill-type Rossby wave response. As a result, the weakened subtropical high and enhanced monsoon trough shift eastward and northward, which favor TC genesis and development. Although such increased TC activity in 2018 might be slightly suppressed by interdecadal climate variability, it was mostly attributed to the favorable interannual background. In addition, high-frequency climate signals,such as intraseasonal oscillations(ISOs) and synoptic-scale disturbances(SSDs), interacted with the enhanced monsoon trough and strongly modulated regional TC genesis and development in 2018.     

2.5-D DC Resistivity Modeling Considering Flexibility and Accuracy

We highlighted the flexibility of using unstructured mesh together with the local refinement by a resistivity model with complicated topography. The effect of topography is emphasized. Based on this, we calculated a specific class of layered models and found that the accuracy is not always satisfactory by utilizing the standard approach. As an improvement, we employed the layered earth as the reference model to calculate the wavenumbers. The comparison demonstrates that the accuracy is considerably improved...     

PROTEM-37瞬变电磁测深系统及应用实例

PROTEM - 37仪器具有分辨率高、动态范围大、抗干扰能力强、探测深度较大等优良性能。简要介绍了该仪器的测深原理、工作装置、野外施工步骤以及资料的处理解释。对TEM和MT资料的联合反演作了有益的尝试。介绍了该仪器在探测地下洞穴、勘察金属矿以及煤田水文地质调查等方面