深水Stokes漂流公式的一种新形式

本文在未将Stokes波的势函数参数β的前提下使用近似解迭代方法重新推导了Stokes波的水质点的轨迹方程。在具体推导中发现水平位移与垂向位移在作近似解迭代时，收敛于精确解的速度是不相同的，垂向位移在一次迭代后即与精确解非常近似，而对于水平位移必须做二次迭代才能达到较好的精度。由二次迭代的水平位移方程即可获得Stokes漂流公式的一种新式，该形式表明，在三阶精度下Stokes漂流与所在深度的水质点的振幅A的平方成正比。运用由垂向位移方程解得的振幅与参数β的关系式可证明经典Stokes漂流公式可以看作是新漂流公式在特定坐标系下的特定垂直断面处的结果。     

Structure of a pair of anticyclonic vortices in northern part of the South China Sea in autumn of 1994

A pair of remarkable meso-scale anticyclonic vortices, one formed closely to another, inthe northern part of the South China Sea during the period from the later August to early September of 1994 were documented by the in situ observation data. Their spatial structures were examined in detail from the horizontal and two nearly perpendicular/vertical angles of view. It was shown that the horizontal scales of these two vortices were around 100, 50 km, and their vertical scales were about 500, 1000 m, respectively. Two "warm core" structures associated with these two vortices were found in their horizontal and vertical analyses. The closer spacing of these two vortices (namely, 60 km), which was smaller than the Rossby radius of deformation, suggested that they might merge with each other during their next evolution stages and form into a larger vortex eventually.     

Modern sedimentation rates in the intertidal zone on the west coast of the Bohai Gulf

On the basis of the measurement of ^210Pbcx and ^137Cs activities in the sediment cores taken from the intertidal zone on the west coast of the Bohai Gulf, the average sedimentation rates of modern sediments are calculated. The results indicate that in the sandy area of the intertidal zone (from Daogouzi to the Duliujian River), the sedimentation rate from 1955 to 1963 is 3.43～4.06 cm/a, and is within the range of 0.65～1.59 cm/a since 1963. The average sedimentation rate in the muddy area (around Qikou) is approximately 1.81 cm/a.The results above suggest that the sandy area of the intertidal zone has experienced rapid sedimentation from the 1950s to the 1960s,and the sedimentation slows down after the 1960s, and the sedimentation rates increase from north to south spatially. The rapid sedimentation from the 1950s to the 1960s in the sandy area is due to the fact that North China has plentiful precipitation during this period and the intertidal zone is supplied with abundant matter sources for sedimentation. After the 1960s, the weakened sedimentation may be a result of the reduction of sand transported to the intertidal zone, which is a consequence of diminished rainfall in North China and intensive human activities in the Haihe basin.     

Redox evolution and mass transfer during serpentinization: An experimental and theoretical study at 200 °C, 500 bar with implications for ultramafic-hosted hydrothermal systems at Mid-Ocean Ridges

Highly reducing and high-pH vent fluids characterize moderately low temperature ultramafic-hosted hydrothermal systems, such as the recently discovered Lost City hydrothermal field at 30°N Mid-Atlantic Ridge Ridge (MAR). To better understand the role of mineral reaction rates on changes in fluid chemistry and mineralization processes in these and similar systems, we conducted an experimental study involving seawater and peridotite at 200 °C, 500 bar. Time series changes in fluid chemistry were monitored and compared with analogous data predicted using experimental and theoretical data for mineral dissolution rates. Although there was qualitative agreement between predicted and measured changes in the chemical evolution of the fluid for some species, the rate and magnitude of increase in pH, dissolved chloride and H₂ did not agree well with predictions based on theoretical modeling results. Experimental data indicate that dissolved H₂ abruptly and intermittently increased, reaching a value only approximately 20% of that predicted assuming magnetite as the primary Fe-bearing alteration phase. The distribution and valence of Fe in primary and secondary minerals reveal that the most abundant secondary mineral, serpentine, contained significant amounts of both ferric and ferrous Fe, with the less abundant brucite, also being Fe-rich (X_Fe = 0.3). Surprisingly, magnetite was present in only trace amounts, indicating that H₂ generation was largely accommodated by the formation of Fe-chrysotile. Accordingly, the diversity of Fe-bearing secondary minerals together with rates of serpentinization less than theoretically predicted, account best for the relatively low dissolved H₂ concentrations produced. Thus, the experimental data can be used to obtain provisional estimates of thermodynamic data for Fe-bearing minerals, enhancing the application of reaction path models depicting mass transfer processes during serpentinization at mid-ocean ridges. Similarly, the observed differences between theoretically predicted and experimentally measured pH values result from constraints imposed by complex patterns of mass transfer inherent to the experimental system. In particular, the experimental observation of a late stage increase in Na/Cl ratio likely results from the dissolution of a Na₂O component of clinopyroxene, which causes pH to increase sufficiently to induce precipitation of a Ca-bearing phase, perhaps portlandite. As with the redox variability observed during the experiment, this event could not be predicted, underscoring the need to use caution when modeling alteration processes in the chemically complex ultramafic-hosted hydrothermal systems at elevated temperatures and pressures.     

宽带啁啾脉冲激光非线性传输过程中的时空微扰研究

基于非线性薛定谔方程推导出大啁啾脉冲的传输方程,利用微扰理论,分析了啁啾脉冲激光的时空不稳定性. 理论上比较清楚的阐述了宽带脉冲激光在大啁啾情况下,其时空噪声的相互影响与相互作用情况及脉冲啁啾对噪声微扰调制的影响,发现在相同γI₀(非线性系数与峰值强度乘积)的情况下脉冲啁啾对噪声调制的增长没有直接影响. 最后我们在实验上利用非线性介质对啁啾脉冲的空间小尺度自聚焦过程进行了部分验证,同时也在数值上对宽带啁啾脉冲的时间噪声调制的增长进行了模拟分析,发现实验结果和模拟分析结论     

聚乙烯冲击压缩特性实验研究

利用神光Ⅱ装置第九路输出的倍频激光,采用直接驱动方式研究了聚乙烯(CH₂)材料的冲击压缩特性.实验表明聚乙烯冲击波阵面自发辐射较强,冲击波在聚乙烯台阶中的传播比较稳定.采用阻抗匹配方法,以铝作标准材料,测量了聚乙烯的冲击绝热线,聚乙烯冲击压强达0.54 TPa,冲击波速度测量相对扩展不确定度~2%(K=2),实验数据的一致性较好,与已有低压实验数据及状态方程解析模型比较符合.     

Study on the total water pollutant load allocation in the Changjiang (Yangtze River) Estuary and adjacent seawater area

With the rapid economic development, the water quality is worsening and red tide takes place frequently in the Changjiang Estuary and adjacent seawaters. To improve the marine water quality, the total inland pollutant load should be controlled effectively. With efficiency and fairness in consideration, the total maximum allowable loads of COD_Mn, NH₃–N, inorganic nitrogen and active phosphate to the seawaters were calculated and allocated by the linear programming method based on the water quality response fields of the pollution sources. The maximum allowable loads are 2008 × 10³ tons, 169 × 10³ tons, 226 × 10³ tons and 18 × 10³ tons for COD_Mn, NH₃–N, inorganic nitrogen and active phosphate when the water quality targets are requested to be achieved in the whole studied region, and 346 × 10³ tons and 32 × 10³ tons for inorganic nitrogen and active phosphate when the water quality targets to be achieved only in the red tide sensitive area. The cut task of COD_Mn and NH₃–N is relatively easy and can be finished by the watershed environmental plan; while the cut task of inorganic nitrogen and active phosphate is tremendous. The coastal provinces should install more denitrification and dephosphorization facilities in the existing waste water treatment plants or build new ones to control the red tides in the concerned seawaters.     

湛江湾真光层深度与初级生产力的时空变化及其影响因素

基于2016−2017年4个季节航次数据,分析了湛江湾真光层深度与初级生产力的时空变化特征及其影响因素。结果表明,湛江湾真光层深度平均值为（6.95±3.17）m,空间变化比季节变化明显,K_d(PAR)与浊度存在显著的正相关关系,建立的线性回归模型R²为0.73（p<0.01）,表明悬浮颗粒物对湛江湾真光层深度的影响占主导地位。利用VGPM模型得到初级生产力（以碳计）的平均值为（639.53±427.95）mg/(m²·d),其时空特征与真光层深度基本保持一致,真光层深度比叶绿素a浓度更能解释初级生产力的时空分布模式。     

南天山乌什前陆逆冲褶皱构造带的晚新生代构造地貌特征与地震活动

乌什逆冲断褶带位于南天山库车前陆逆冲褶皱构造带的西段,对该地区晚新生代构造活动的研究有利于加深对南天山前陆逆冲构造带的认识。本文通过对卫星遥感影像和DEM数据的解译分析,并结合研究区野外考察及典型地震反射剖面的分析,表明乌什逆冲断褶带东部地貌演化受褶皱生长影响较为深刻,发育一系列由新到老的冲积扇和风口。台兰河中游河流阶地和冰碛物均被秋里塔格断层错断,阶地断距为31～67 m,台兰期冰碛物(M2)断距约80 m。秋里塔格断裂第四纪以来水平缩短速率约为123～159 mm／a。西部地区发育一系列逆冲断层,并发育典型的活动断层陡坎。乌什凹陷地震活动也具有明显的西强东弱的特点,地震活动具有沿断层呈带状分布的特点。乌什逆冲断褶带位于南天山造山带东西构造的转换地带,地震活动西部明显强于东部,且具有呈带状沿南天山及其山前逆冲断裂带分布的特点。历史地震分析表明上个世纪以来该区域未有7级以上地震发生,但其西部地区6级以上地震频发,随着阿克苏地区区域经济的快速发展和人口的快速增长,乌什逆冲断褶带的地震活动性应该引起地质学家更加深入的关注和研究。     

Spatiotemporal variations of potential evapotranspiration and aridity index in relation to influencing factors over Southwest China during 1960–2013

This study investigated the spatial–temporal patterns and trends of potential evapotranspiration (ET₀) and aridity index (AI) over Southwest China during 1960–2013 based on daily temperature, precipitation, wind speed, sunshine duration, total solar radiation, and relative humidity data from 108 meteorological stations. The Penman–Monteith model, Mann–Kendall (M–K) test, moving t test, and Morlet wavelet method were used. The results indicated that ET₀ and AI across the region displayed decreasing trends, but the former was significant. After 2000, regionally average trends in ET₀ and AI increased rapidly, indicating that droughts increased over Southwest China in recent years. Spatially, the changes of ET₀ and AI were dissimilar and not clustered, either. Temporally, both ET₀ and AI displayed obvious abrupt change points over different timescales and that of AI was during the winter monsoon period. Significant periodic variations with periods of 27, 13, and 5 years were found in ET₀, but only of 13 and 5 years existed in AI. Correlation analysis revealed that the sunshine duration and wind speed were the dominant factors affecting ET₀ and that AI showed strong negative correlation with precipitation. The findings of this study enhance the understanding of the relationship between climate change and drought in Southwest China, while the mechanism controlling the variation in drought requires further study.