Relationships between chlorophyll a, bacteria, ATP, POC and respiration rates in the Changjiang Estuary and the plume

Bacteria abundance, chlorophyll a, ATP and POC concentrations and respiration rates of microorganisms in the Changjiang Estuary and the plume were determined in July 1986. The high values of bacteria abundance occurred in the river mouth in association with suspended matter. It is assumed that bacteria were the major contributor to ATP and the main consumer of dissolved oxygen, and that the relationship between ATP and POC was present in that area. In the dilution zone (salinity; 25-30), instead of bacteria, phytoplankton was the major contributor to ATP and respiration rates, due to diatom bloom. Close relationships between Chi a and ATP, and ATP and POC were observed. Contribution of microbial carbon to POC was also estimated.     

胶州湾海鞘类 Ⅱ、柄海鞘科Styelidae

本文为胶州湾海鞘类区系研究之一,涉及柄海鞘科2属7种,其中二种为新种。     

基于CFD方法的十字形降落伞–航行体系统数值分析

为研究航行体对十字形降落伞流场和阻力性能的影响,基于Realizablek–ε模型采用PISO算法开展了十字形降落伞–航行体系统的非定常绕流数值计算,得到了详细的流场计算结果。研究了不同拖曳比下十字形降落伞–航行体系统的流场分布规律与降落伞衣及航行体的气动特性变化,结果表明：当拖曳比λ≤2时,航行体和降落伞衣形成闭式流动,降落伞衣阻力损失严重;当拖曳比λ>2时,航行体尾流区的压力恢复,降落伞衣底部形成稳定的正压区,流动形式由闭式转化为开式,拖曳比λ最大时的压差Δp相较拖曳比最小时的压差增加12%,降落伞衣阻力恢复,阻力波动减小;当拖曳比λ=4时,降落伞与航行体的阻力分别增加1.8%、25%。结果显示十字形降落伞–航行体系统的流场和压力分布更为对称,且气动特性处于最佳状态。     

Environmental impact of fluidized solidified silt casting on surrounding water bodies

Abstract

With the growing demand for underwater refill engineering, the construction technology of implementing fluidized solidification in underwater pouring has recently received increased attention. However, the environmental impact of underwater casting on surrounding water bodies, especially when the silt is polluted, is still unclear. In this study, a simulated underwater pouring test and a static immersion release test were conducted separately to study the quality of the surrounding water during and after pouring. The results showed that fluidized-solidified silt casting could increase the pH of the surrounding water, even after the pouring had stopped, by approximately 1.0 and the turbidity could reach 200 NTU. No diffusion of Zn and Cu into the surrounding water was observed and while Ni and Cr exhibited slight diffusion, this was at a level well below international water quality standard. During construction, reducing the distance from the seafloor to the bottom of the pouring catheter could reduce the level of pollution. After construction, the use of neutral solidified materials can effectively reduce the pH of the surrounding water and the potential risk of heavy metal dissolution.     

Gradation affects basic mechanical characteristics of Chinese calcareous sand as airport subgrade of reefs

Abstract

Construction of the reefs in the South China Sea is a significant foundation to the secure stability and economic development of China. The construction of an airport runway is necessary for this realization. The calcareous sand is the main primary material in the runway construction. A certain type of calcareous sand near a certain reef of the South China Sea was studied in this paper. To investigate this specific calcareous sand, quartz sand was used as a reference for comparison. Microscopic 3-D imaging, compression and triaxial tests were conducted to test the micro, squeezing and shear properties. The effect mechanism of gradation on the calcareous sand’s compressibility and shear characteristics are discussed from a mesoscopic viewpoint using 3-D morphology. Calcareous sand particles are multiangular and flatter in comparison with quartz sand. The larger the particle sizes are, the more different the two sands’ morphologies are. The compressibility of calcareous sand is greater, and the effect of the coarse fraction (5–1?mm) content in the gradation plays the most significant role in this feature. When the coarse particles’ content is less than 25% and the mass ratio of the middle and fine particles (M) is constant, there is the worst coarse fraction content causing the calcareous sand to be most likely compressed. The worst coarse fraction content decreases with the increase in M, and an empirical formula is proposed. When the gradation, relative density and confining pressure are the same, the peak shear stress and strain of calcareous sand are all at a high level. The effect of confining pressure is manifested in calcareous sand. The shear strength and dilation of calcareous sand are also most affected by the medium coarse fraction (5–0.25?mm) content.     

Undrained monotonic shear behavior of marine soft clay after long-term cyclic loading

Abstract

In the coastal area, nearshore and offshore structures have been or will be built in marine soft clay deposits that have experienced long-term cyclic loads. Therefore, the mechanical behavior of marine clay after long-term cyclic loading needs to be investigated. In this research, a series of monotonic and cyclic triaxial tests were carried out to investigate the postcyclic mechanical behavior of the marine soft clay. The postcyclic water pore pressure, shear strength and secant stiffness are discussed by comparing the results with the standard monotonic test (without cyclic loading). It is very interesting that the postcyclic behavior of marine soft clay specimen is similar to the behavior of overconsolidated specimen, that is, the specimen shows apparent overconsolidation behavior after long-term cyclic loading. Then relationship between the overconsolidation ratio and the apparent overconsolidation ratio is established on the basis of the theory of equivalent overconsolidation. Finally, a validation formula is proposed which can predict the postcyclic undrained shear strength of marine soft clay.     

加味桂枝甘草龙骨牡蛎汤治疗心阳不振型室性早搏35例临床观察

目的:观察加味桂枝甘草龙骨牡蛎汤治疗心阳不振型室性早搏的临床疗效。方法：将70 例心阳不振型室性早搏患者随机分为治疗组和对照组,每组各35 例。对照组予以琥珀酸美托洛尔缓释片治疗,治疗组在对照组基础上联合加味桂枝甘草龙骨牡蛎汤治疗。比较2组治疗前后的中医证候积分、24 h室性早搏次数及不良反应发生情况,并评定综合疗效。结果：总有效率治疗组为88.57%（31/35）,对照组为62.86%（22/35）,2组比较,差异有统计学意义（P<0.01）;2组中医证候积分及24 h室性早搏次数治疗前后组内比较及治疗后组间比较,差异均有统计学意义（P<0.01）。2组均出现轻度胃部不适、恶心等不良反应,其中治疗组2 例,对照组1 例。结论：加味桂枝甘草龙骨牡蛎汤能有效改善心阳不振型室性早搏患者的症状,减少室性早搏发生次数,值得临床推广和应用。     

几种海洋蓝藻生长条件的研究

对Ｓｙｎｅｃｈｏｃｏｃｃｕｓ ｂａｃｉｌｌａｒｉｓ，Ｏｓｃｉｌｌａｔｏｒｉａ ｌｕｄ，Ｓｃｈｉｚｏｔｈｒｉｘ ｃａｌｃｉｃｏｌａ，Ｓｐｉｒｕｌｉｎａ ｐｌａｔｅｎｓｉｓ等４各海洋蓝藻的生长条件的研究表明，除Ｓ．ｐｌａｔｅｎｓｉｓ外，其他３种蓝藻在“ｆ／２”培养基中生长良好，外源生长因子对生长有不同程度的促进作用。Ｓ．ｂａｃｉｌｌａｒｉｓ适应较高光强，其温度和ｐＨ最适范围较窄，Ｓ．ｃａｌｃｉｃｏｌａ     

赤潮发生机理研究──海洋原甲藻的氮营养生理特征

于１９９１年１月－１９９１年１２月，以不同浓度的硝态氮（２０，６０，２００，６００μｍｏｌ／Ｌ）研究对赤潮生物海洋原甲藻的生长和生化组成的影响，及其营养生理特性，结果表明，在氮浓度为２００和６００μｍｏｌ／Ｌ时，表现光合作用强，细胞生长快，指数生长期长，叶绿素含量高，提示了由原甲藻爆发引起的赤潮与海洋富营养化有直接关系，结果还表明，海洋原甲藻可以累积蛋白质和碳水化合物，当外界氮源不能满足生长需要时     

南海波高熵和风速熵

根据风速的统计分布，给出了有因次风速熵和无因次风速熵的定义及其计算方法，使用ＧＥＯＳＡＴ高度计１９８６年１１月－１９８９年２月的有效波高和风速的资料，计算，分析了南海海域上的波高熵，风速熵，给出它们的时间变化特征和空间变化特征，并对不同随机量的无因次熵，即随机度进行了比较。