The influence of 70 and 120 kHz tonal signals on the behavior of harbor porpoises (Phocoena phocoena) in a floating pen

Two harbor porpoises in a floating pen were subjected to five pure tone underwater signals of 70 or 120kHz with different signal durations, amplitudes and duty cycles (% of time sound is produced). Some signals were continuous, others were intermittent (duty cycles varied between 8% and 100%). The effect of each signal was judged by comparing the animals' surfacing locations and number of surfacings (i.e. number of respirations) during test periods with those during baseline periods. In all cases, both porpoises moved away from the sound source, but the effect of the signals on respiration rates was negligible. Pulsed 70kHz signals with a source level (SL) of 137dB had a similar effect as a continuous 70kHz signal with an SL of 148dB (re 1muPa, rms). Also, a pulsed 70kHz signal with an SL of 147dB had a much stronger deterring effect than a continuous 70kHz signal with a similar SL. For pulsed 70kHz signals (2s pulse duration, 4s pulse interval, SL 147dB re 1muPa, rms), the avoidance threshold sound pressure level (SPL), in the context of the present study, was estimated to be around 130dB (re 1muPa, rms) for porpoise 064 and around 124dB (re 1muPa, rms) for porpoise 047. This study shows that ultrasonic pingers (70kHz) can deter harbor porpoises. Such ultrasonic pingers have the advantage that they do not have a "dinner bell" effect on pinnipeds, and probably have no, or less, effect on other marine fauna, which are often sensitive to low frequency sounds.     

Correction of the effect of relative wind direction on wind speed derived by advanced microwave scanning radiometer

The sea surface wind speed (SSWS) derived by a microwave radiometer can be contaminated by changes of the brightness temperature owing to the angle between the sensor azimuth and the wind direction (Relative Wind Direction effect: RWD effect). We attempt to apply the method proposed by Konda and Shibata (2004) to the SSWS derived by Advanced Microwave Scanning Radiometer (AMSR) on Advanced Earth Observing Satellite II (ADEOS-II), in order to correct for the RWD effect. The improvement of accuracy of the SSWS estimation amounts to roughly 60% of the error caused by the RWD effect. Comparison with in situ observation at the Tropical Atmosphere Ocean (TAO) array shows that the root mean square error of the corrected SSWS is 1.1 ms⁻¹. It is found that the impact of the RWD effect on the estimation of the latent heat flux can amount to about 30 Wm⁻² on average. We applied the method to the SSWS derived by AMSR for Earth Observing System (AMSR-E) and obtained a similar result.     

Geometrical Evaluation on the Viscous Effect of Point-Absorber Wave-Energy Converters

The fluid viscosity is known to have a significant effect on the hydrodynamic characteristics which are linked to the power conversion ability of the wave energy converter (WEC). To overcome the disadvantages of case-by-case study through the experiments and numerical computations employed by the former researches, the viscous effect is studied comprehensively for multiple geometries in the present paper. The viscous effect is expressed as the viscous added mass and damping solved by the free-decay method. The computational fluid dynamics (CFD) method is employed for the calculation of the motion and flow field around the floater. The diameter to draft ratio and bottom shape are considered for the geometrical evaluation on the viscous effect. The results show that a slenderer floater presents a stronger viscous effect. Through the comparisons of the floaters with four different bottom shapes, the conical bottom is recommended in terms of low viscous effect and simple geometry for manufacture. A viscous correction formula for a series of cylindrical floaters is put forward, for the first time, to help the engineering design of outer-floaters of point-absorber WECs.     

Effect of dissolved phosphorus on alkaline phosphatase activity in marine microalgae

I~IOXThe alkaline phOSPhataSe (AP) has been more and more studied following the study of thephosphorus limitation (Suttle and Harrision, 1988; Hu et al., 1989; Huang et al., 1996). PeOple used to take dissolved inorganic phOSphorus (DIP) level and uptake rate by algae as phosphOrus limitation indicators (Vera and Petterson 1992; Huang and HOng, 1994). But recent resultsindicate that diSSOlved organic phosphorus (DOP) and particulate organic phOSphorus (PP) couldalso be utilized b…     

Induced-current effects on microwave backscatter

Microwave measurements have been made with a coherent radar in a wind-wave tank to determine the effect of induced current on backscatter. Perturbations were introduced into the wave structure by inducing a current in the water that flowed either with or against the wind. The effect of current on radar cross section was slight; the effect on the Doppler was much more pronounced. It was found that the wave components responsible for radar backscatter are predominantly free waves (that is, waves which travel at the dispersion velocity) rather than waves which are parasitic (or locked) to the dominant waves.     

牛蒡寡糖对双歧杆菌体外生长的促进作用

牛蒡寡糖是从菊科植物牛蒡（Arctium lappa L．）的等外根中提取得到的一种水溶性的果寡糖。将牛蒡寡糖代替葡萄糖作为培养基的碳源,考察了双歧杆菌体外生长的情况,并探讨了牛蒡寡糖对双歧杆菌生长的作用效果。结果表明,牛蒡寡糖对双歧杆菌体外生长有显著的促进作用,优于葡萄糖作碳源时的效果（P〈0．05）。培养基中牛蒡寡糖的最适添加量为1．0％～2．0％（m／V）。牛蒡寡糖不仅能缩短双歧杆菌生长的适应期,而且能使其显著增殖。     

Reynolds and Mass-Damping Effect on Prediction of the Peak Amplitude of A Freely Vibrating Cylinder

The Reynolds effect and mass-damping effect on the peak amplitude of a freely vibrating cylinder is studied by using forced oscillating data from Gopalkrishnan＇ s research in 1993, in which all experimental cases were carried out at a fixed Reynolds and the tested cylinder was recognized as a body that had no mass and damping. However, the Reynolds and roass-damping are the very important parameters for the peak amplitude of a freely vibrating cylinder. In the present study, a function F is introduced to connect the forced oscillation and free vibration. Firstly the peak amplitude AG^＊ can be obtained from the function F using forced oscillation data of Gopalkrishnan＇ s experimental at Re = 10^4, and then the Reynolds effect is taken into account in the function f（Re）, while the mass-damping effect is considered in the function K（ α ）, where a is the mass-damping ratio. So the peak amplitude of a freely vibrating cylinder can be predicted by the expression： A ^＊ = K（ α ）f（ Re ）AG^＊ . It is found that the peak transverse amplitudes predicted by the above equation agree very well with many recent experimental data under both high and low Reynolds conditions while roass-damping varies. Furthermore, it is seen that the Reynolds number does have a great effect on the peak amplitude of a freely vibrating cylinder. The present idea in this paper can be applied as an update in the empirical models that also use forced oscillation data to predict the vortex induced vibration （VIV） response of a long riser in the frequency domain.     

海水中氨基酸对Cu(Ⅱ)—蒙脱石、SiO_2之间离子交换的影响

本文研究了海水中组氨酸、天冬氨酸、丙氨酸对Cu(Ⅱ)—蒙脱石、SiO_2之间离子交换率(%)—pH曲线的影响。结果表明,低浓度氨基酸促进Cu(Ⅱ)—蒙脱石之间离子交换,而高浓度则起抑制作用;但低浓度氨基酸对Cu(Ⅱ)—SiO_2离子交换没有影响,而高浓度起抑制作用。分析表明,氨基酸的促进效应与表面三元络合物相关,而抑制效应与液相中Cu(Ⅱ)—氨基酸络合反应相关。     

三个牙鲆育种群体亲本效应及遗传参数估计

针对牙鲆(Paralichthys olivaceus)养殖品种生长速度变慢、抗病力降低这一问题。近年来构建了牙鲆抗病群体(RS)、日本群体(JS)和黄海群体(YS)3个育种群体,开展牙鲆选择育种,建立了63个家系,收集了所有家系5 328尾鱼苗的体长和体重数据。借助线形混合模型(Linear mixedmodel)、"加性-显性"模型、约束极大似然法(REML)及最佳线性无偏预测(BLUP)分别估计亲本效应值、体重和体长遗传力和遗传相关、父母本效应和杂交效应。预测结果显示,其中父本130,141,146,170,218,229,303和308随机效应达到了极显著效应水平(P<0.01),父本112,122,141,190,212达到显著水平(P<0.05),所有母本体重随机效应达到了极显著水平(P<0.01);体长和体重两性状的加性、显性、表型和基因型相关分量都达到极显著水平(P<0.01),体长和体重的加性方差比率均大于显性方差比率,可见两性状的遗传效应主要取决于基因的加性效应。体长的总遗传效应率为31.20%,体重的总遗传效应率为33.58%,体长和体重的随机方差比率分别达到68.80%和66.41%,说明养殖环境等因素对牙鲆体长和体重的影响较大,同时说明在牙鲆选择育种中消除环境影响极为重要。体长和体重的狭义遗传率分别为0.199和0.256(P<0.01),广义遗传率分别为0.312和0.336(P<0.01),牙鲆在以上两性状上属于中等遗传力,通过选择育种可取得较大的遗传进展。对3个牙鲆育种群体杂交随机效应估计结果显示,抗病群体和黄海群体在体长和体重两性状上加性随机效应显著(P<0.05);抗病群体分别与日本群体、黄海群体杂交,其后代表现出显性随机效应达到0.10的水平(P<0.10),黄海群体自交、日本群体和黄海群体杂交随机效应不显著(P>0.05),因此在杂交组配中选择抗病群体与其他两个群体交配可取得较好的效果。     

中国海水养殖净碳汇效率的空间演进与外溢效应

提高海水养殖净碳汇效率是中国实现碳中和目标的重要途径之一。文章运用超效率SBM模型测算2008—2019年中国沿海9地海水养殖净碳汇效率,并对其全局和局部空间自相关性进行分析,然后采用动态空间杜宾模型探究海水养殖净碳汇效率的影响因素及其空间溢出效应。研究发现：中国海水养殖净碳汇效率水平整体较高且呈上升态势,但地区差异明显。从全局看,地区海水养殖净碳汇效率存在空间正相关关系,集聚效应显著,但随着时间的推移,空间集聚程度逐渐减弱;从局部看,研究期间部分地区净碳汇效率的空间演进路径未发生变动,呈现出一定的路径依赖特征。科技推广、产量结构对海水养殖净碳汇效率具有促进作用,经济规模、专业人员投入强度具有抑制作用;从空间溢出效应看,专业人员投入强度、科技推广和产量结构对邻近地区净碳汇效率存在正向溢出效应,经济规模存在负向溢出效应。     

Numerical simulation of water content dependent undrained shear strength of clays

Abstract

A nonlinear mathematical model for estimating the water content dependent undrained shear strength of clayey soils was developed. Three types of clay mixtures (kaolinite, bentonite, and kaolinite-bentonite) were considered. The shear strength of the given soil samples was determined via torvane tests. Experimental results were compared with three numerical results: (i) the analytical function fit, (ii) modeling without the water content effect, and (iii) modeling with the water content effect using the Mohr-Coulomb (M-C) model. There was good agreement among the experimental, analytical, and numerical results with and without the water content effect in the fully softening zone. However, there was a large difference between the numerical results obtained from the developed model with and without the water content effect in the flow zone with a high liquidity index, because the shear strength may decrease significantly to low value in the case of an abrupt increase of the water content. The greatest advantage of the developed model is that it can simulate the reduction of the shear strength and shear band development under the high water content condition, which may trigger a large mobile mass movement.     

Effect of a snow cover on microwave backscatter from sea ice

The effect of a snow cover on sea ice upon radar backscatter at microwave frequencies (X- andKu-baud) can be important. The effect of scattering from the snow cover on thesigmadegof first-year ice is shown to be severe (5 cm of dry snow can raisesigmadegby 8 dB at 9 GHz), while that onsigmadegof multiyear ice is shown to be smaller. The low thermal conductivity of snow compared to that of sea ice effectively raises the temperature of the upper surface of the ice, resulting in higher dielectric constants for the ice, thereby modifying the backscatter both from the ice surface and from the scattering volume. The temperature effect of a 10-cm snow cover on 3-m-thick multiyear ice is to lower thesigmadegby only about 0.3 dB for air temperature of-20degC. The effect on 1-m-thick first-year ice is even less. Hence, the volume-scattering effect of snow is more important than the temperature effect. The presence of a wet snow cover can block the volume-scattering contribution of the multiyear ice. The effect of wet snow cover on first-year ice should be smaller than that Of dry, snow, becausesigmadegof wet snow is lower than that of dry snow.     

Extremely low magnetic fields as a factor of modulation and synchronization of infradian biorhythms in animals

The studies of the influence that a magnetic field (MF) with a frequency of 8 Hz has on the infradian rhythms of physiological and metabolic processes indexes in animals have been carried out in order to verify the hypothesis on the synchronizing effect of natural electromagnetic fields. It is shown that the MF effect has alternating characteristics of the time organization of energetic physiological and metabolic processes in animal organisms in an infradian range and the partial smoothing of biorhythmic deviations between individual-typological groups of organisms occurs for single processes. This (i) shows the common system reaction mechanisms that the organisms of animals have to the effect of a certain factor and (ii) is evidence of the synchronizing influence of the daily influence of magnetic fields of extremely low frequencies on populations of organisms with initially different biorhythmic types. It has been concluded that the stable variations of electromagnetic background, including natural, can serve as a timer for biorhythms in a wide range of periods.     

刺网选择性对鱼类表型性状的选择作用研究

本研究从刺网选择性对鱼类表型性状的影响入手,应用数值模拟方法,模拟了一个具有一定体长特征的鱼类种群,利用具有多项选择参数(曲线标准差σ,最适体长l0,选择性因素R0)的刺网曲线对其进行长期捕捞作用,并在去除捕捞的情况下探讨这种影响的稳定性。结果表明,刺网捕捞作业长期作用于鱼类种群,会对种群体长组成产生深远的影响,开发率(E)越大,效果越明显。当刺网最适捕捞体长与初始种群优势体长重合时(l0=15),造成种群体长分布峰值的分化;如果l0>15,则导致种群体长组成向小型化方向偏移;反之则会造成种群体长组成向大型化方向偏移;而且这种影响可能伴随遗传因素,具有不可逆性。     

2008年孟加拉湾春季暖池生消过程的热收支诊断分析

在夏季风爆发前孟加拉湾会出现季节性暖池,在季风爆发后它则快速消失。本文利用RAMA浮标阵列中孟加拉湾中部浮标的观测资料,通过进行混合层热收支诊断,对2008年孟加拉湾春季暖池的生消过程进行了分析。结果表明:热通量项主导了暖池的生成和消亡过程,它在暖池生成期表现为强加热效应,而在暖池消亡期变为强冷却效应;垂向卷夹的冷却作用在暖池生成阶段比较突出;温度平流项的冷却作用在冬季较强。对热通量项的进一步分析表明:短波辐射平均热效应在暖池生成期高达0.32℃/d,而在暖池消亡期降低一半,这是使热通量项在两个时期有不同表现的根本原因;潜热通量在各阶段的平均冷却效应基本保持不变,都在-0.14℃/d左右;长波辐射的冷却效应在暖池生成期比较显著,一定程度上减缓了海温的上升速度;感热通量的热效应相对较小。     

Combined tidal and wind driven flows and residual currents

The effect of a residual current on the combined tidal and wind driven flow and the resulting bedload sediment transport in the ocean has been investigated, using a simple one dimensional two-equation turbulence closure model. Predictions of the combined tidal and wind driven flow with given residual currents are presented, showing that the residual current has a substantial effect on both the depth averaged mass transport and the mean bedload transport directions; in some cases the effect of the residual current is to almost reverse the mean bedload transport direction. The residual current affects the rotation of the flow due to the Coriolis effect in the lower part of the water column (the near-surface flow is wind dominated), causing a larger or smaller clockwise rotation of the depth averaged mass transport, depending on the direction of the residual current.     

Wave Power Focusing due to the Bragg Resonance

Wave energy has drawn much attention as an achievable way to exploit the renewable energy. At present, in order to enhance the wave energy extraction, most efforts have been concentrated on optimizing the wave energy convertor and the power take-off system mechanically and electrically. However, focusing the wave power in specific wave field could also be an alternative to improve the wave energy extraction. In this experimental study, the Bragg resonance effect is applied to focus the wave energy. Because the Bragg resonance effect of the rippled bottom largely amplifies the wave reflection, leading to a significant increase of wave focusing. Achieved with an energy conversion system consisting of a point absorber and a permanent magnet single phase linear motor, the wave energy extracted in the wave flume with and without Bragg resonance effect was measured and compared quantitatively in experiment. It shows that energy extraction by a point absorber from a standing wave field resulted from Bragg resonance effect can be remarkably increased compared with that from a propagating wave field (without Bragg resonance effect).     

河口变形效应与涌潮的形成

作者采用非线性潮波方程,假定河口的宽度B(x)和深度h(x)是任意可微函数,导出了涌潮发生的条件,并讨论了各种变形情况下涌潮的形成。得出结论是,在涌潮形成过程中起决定作用的是浅水非线性效应,而河口变形效应则是起促进作用的。     

Numerical study of a round buoyant jet under the effect of JONSWAP random waves

This paper presents a numerical study on the hydrodynamic behaviours of a round buoyant jet under the effect of JONSWAP random waves. A three-dimensional large eddy simulation (LES) model is developed to simulate the buoyant jet in a stagnant ambient and JONSWAP random waves. By comparison of velocity and concentration fields, it is found that the buoyant jet exhibits faster decay of centerline velocity, wider lateral spreading and larger initial dilution under the wave effect, indicating that wave dynamics improves the jet entrainment and mixing in the near field, and subsequently mitigate the jet impacts in the far field. The effect of buoyancy force on the jet behaviours in the random waves is also numerically investigated. The results show that the wave effect on the jet entrainment and mixing is considerably weakened under the existence of buoyancy force, resulting in a slower decay rate of centerline velocity and a narrower jet width for the jet with initial buoyancy.     

Greenhouse effect in planetary atmospheres caused by molecular symmetry breaking in intermolecular interactions

It is believed that the greenhouse effect is related to the parameters of absorption spectra of polyatomic molecules, usually trace gases, in planetary atmospheres. The main components of all known atmospheres of celestial bodies are symmetrical molecules that do not possess the dipole-allowed purely rotational (and in the case of diatomic molecules, vibrational–rotational) absorption spectrum. Upon increased pressure, a weak absorption appears, induced by intermolecular interaction, which can lead to a greenhouse effect. The contribution of the induced absorption in radiative forcing of a dense atmosphere may amount to a few or even tens of W/m². In conditions typical for the atmospheres of terrestrial planets (including paleoatmospheres), the collision-induced absorption and associated greenhouse effect may lead to an increase in surface temperature above the freezing point of water. There is a correlation between the temperature of an atmosphere and the intermolecular bonding energy of gases that dominate in planetary atmospheres of the Solar System.