Diel Patterns in Chlorophyll <Emphasis Type="Italic">a</Emphasis> Specific Absorption Coefficient and Absorption Efficiency Factor of Picoplankton

Diel patterns in the chlorophyll a specific absorption coefficient of surface picoplankton, a*_pico (γ) (m²·[mg chlorophyll a]⁻¹), were studied at 7 stations under daily cycle of in situ light condition in the western subarctic Pacific and Japan Sea. All the data were normalized by dividing the anomaly with daily averaged a*_pico (γ). Opposite diel patterns were observed for the normalized a*_pico (443) and a*_pico (675) with maximum toward dawn or dusk and minimum toward midday at 4 stations under low-irradiance (LI) conditions and vice versa at 3 stations under high-irradiance (HI) conditions. The absorption efficiency factors at red absorption peak, Q _a (675), were determined by reconstruction with intracellular chlorophyll a concentration and cell diameter. The normalized Q _a (675) also showed diel pattern with maximum toward midday and minimum toward dawn or dusk under LI. The diel pattern in a*_pico (675) and Q _a (675) were primarily caused by changes in intracellular chlorophyll a concentration due to photoadaptation under LI. The diel pattern in a*_pico (443) was influenced by pigmentation, as recognized by blue to red ratio [a*_pico (443)/a*_pico (675)] under HI. This study proposed that the opposite diel pattern in a*_pico (γ) might occur for a wide range of algal species. The results presented here have important consequences for the interpretation of diel variations in optical properties observed in the open ocean.     

由粒子吸收光谱提取浮游植物吸收光谱的人工神经网络方法

基于现场实验数据集及人工神经网络技术,论文提出了一种从海中粒子吸收光谱提取浮游植物吸收光谱的方法。这个数据集包含了海中粒子吸收光谱和对应的浮游植物吸收光谱,并被分为三个子集:训练集、印证集和试验集。本研究所利用的人工神经网络系统为多层感知器,训练后的人工神经网络的性能由印证集和试验集来评价。实验结果表明,文中所提出的方法可成功地提取浮游植物的吸收光谱,其提取精度与传统的实验方法相当。     

温度、体重和摄食水平对花尾胡椒鲷幼鱼粪便比能值及吸收率的影响

鱼类没有消化的食物通过粪便而排出体外.没有消化的食物、黏液、消化道脱落细胞、代谢酶以及细菌等就组成了鱼类的粪便.排粪后所保留的食物能可以通过吸收率来估算,其计算式为:A=C-FC/C×100%,式中A(吸收率)以百分数表示;C(摄食量)等于摄入的食物质量乘以食物比能值;F(粪便排出量)等于排出的粪便质量乘以粪便比能值.吸收率在营养学上又称为消化率.粪便比能值的测定在计算吸收率时是非常必要的,但在以往对鱼类吸收率的研究[1～6]中,由于粪便收集的困难及粪便的样品量通常很少,均没有对不同条件下鱼类所排出粪便的比能值进行单独的测定.     

宁镇地区的限制性断层

宁镇山脉的褶皱带被一系列横断层分割为褶断段。横断层相邻的断块,无论是褶皱的形态、纵断层的数目、规模和断距等特征沿纵向跨越横断层均存在不连续性的跃变,表明这些横断层是早于褶皱或与之伴生的纵断层而存在,并对各断块内发育的地质构造起到限制作用。因横断层作为较早的边界,后期的挤压在被分割的各块段内可以是有差异的,导致宁镇褶皱带在总体上的一致性,分段上的有特殊性。     

Numerical Study on Instantaneous Discharge of Unsorted Particle Cloud in Cross Flow

The mixing characteristics of particles such as dredged sediment of variable size discharged into cross flow are studied by a 3D numerical model, which is developed to model the particle-fluid two-phase flow. The Eulerian method with the modified k-ε parameterization of turbulence for the fluid phase is used to solve fluid phase, while a Lagrangian method for the solid phase (particles), both the processes are coupled through the momentum sources. In the model the wake turbulence induced by particles has been included as additional source term in the k-ε model; and the variable drift velocities of the particles are treated efficiently by the Lagrangian method in which the particles are tracked explicitly and the diffusion process is approximated by a random walk model. The hydrodynamic behavior of dumping a cloud of particles is governed by the total buoyancy of the cloud, the drag force on each particle and the velocity of cross-flow. The computed results show a roughly linear relationship between the displacement of the frontal position and the longitudinal width of the particle cloud. The particle size in the cloud and the velocity of cross flow dominate the flow behavior. The computed results are compared with the results of laboratory experiments and satisfactory agreement is obtained.     

Spatial and Temporal Variations of Sound Speed at the PN Section

Gridded sound speed data were calculated using Del Grosso's formulation from the temperature and salinity data at the PN section in the East China Sea covering 92 cruises between February 1978 and October 2000. The vertical gradients of sound speed are mainly related to the seasonal variations, and the strong horizontal gradients are mainly related to the Kuroshio and the upwelling. The standard deviations show that great variations of sound speed exist in the upper layer and in the slope zone. Empirical orthogonal function analysis shows that contributions of surface heating and the Kuroshio to sound speed variance are almost equivalent. This revised version was published online in July 2006 with corrections to the Cover Date.     

关于修改港工钢筋混凝土规范小偏心受压构件正截面强度计算的建议

本文提出在小偏心受压构件正截面强度计算中，取消弯曲抗压强度ｆｃｍ（Ｒｗ），采用轴心抗压强度ｆｃ，这与构件的实际破坏形态相符。对小偏心受压构件正截面强度计算提出了设计建议。特别是对工程上大量应用的矩形截面对称配筋小偏压构件提示了简捷的设计方法，与以往的近似计算方法相比具有物理概念明确，精度高，方法简捷的特点。     

Discussion on Coastal Erosion Near Xizhuang, Penglai, China

-In this work, on the basis of the characteristics of coastal erosion near Xizhuang (Penglai, Shandong, China) and the in-situ measured data and theoretical calculation, the causes of coastal erosion there are obtained: (1) natural erosion, (2) beach sand borrowing, and (3) sand borrowing at the Dengzhou shoal near Xizhuang, which results in the loss of the function of the wave force resistance of the shoal. Since the wave energy is increased, the longshore sediment transport rate is increased. Coastal erosions are more and more serious. A scientific basis to reduced the calamity of coastal erosion in local area is presented. Some experiences are accumulated for studying coastal erosion.     

河口潮位在频域内的一种插补模型

若把河口潮位时间序列简单地看为单输入和输出线性系统模型的输入输出信号，借助频谱分析可以将它们在频域内的关系建立起来，用来进行潮位序列的插补，带通滤波技术的应用可使模型的计算精度大大提高     

泥河湾盆地洞沟剖面的光谱光度时间序列

泥河湾盆地东部的洞沟剖面出露一套以湖相为主的地层,其顶部覆盖了末次间冰期古土壤与末次冰期黄土。测量了该剖面的光谱光度和磁化率,结果显示,亮度(L*)随深度的变化趋势基本与色度a*、色度b*相反,即低亮度值对应高色度值。砂层的亮度值相对低,而质量磁化率高。亮度记录可以与洛川黄土剖面的磁化率记录对比,即亮度低值段可与磁化率高值段对比,这可能源于两者都受东亚季风的控制。对比后获得了30个时间控制点,在此基础上,建立了洞沟剖面测量参数的时间序列。谱分析表明,各参数的时间序列显示了主要的米兰科维奇周期,这显示泥河湾古湖沉积物对古气候的周期性变化敏感。