Secondary production of the eusirid amphipod <Emphasis Type="Italic">Pontogeneia rostrata</Emphasis> Gurjanova, 1938 (Crustacea: Peracarida) on a sandy shore in Korea

The secondary production of the eusirid amphipod Pontogeneia rostrata Gurjanova, 1938, was examined on a sandy shore in Korea. Secondary production was estimated using a size-frequency method. The biomass structure of P. rostrata included one peak in spring, with maximum biomass occurring in April. The annual secondary production of this species was 0.57 g DW m⁻² yr⁻¹ with an annual P/B ratio of 6.97. Secondary production of P. rostrata fell within the range observed for other amphipods on intertidal sandy shores, although the production/biomass (P/B) ratio was higher than those recorded previously from the sampling site and from other tidal and estuary areas, as the number of generations increases the P/B ratio. The results showing high abundance and P/B ratios suggest that P. rostrata plays an important role in the sandy shore ecosystem as a trophic link between primary producers and higher consumers.     

Robust control based on feedback linearization for roll stabilizing of autonomous underwater vehicle under wave disturbances

In the case of Autonomous Underwater Vehicle(AUV) navigating with low speed near water surface,a new method for design of roll motion controller is proposed in order to restrain wave disturbance effectively and improve roll stabilizing performance.Robust control is applied,which is based on uncertain nonlinear horizontal motion model of AUV and the principle of zero speed fin stabilizer.Feedback linearization approach is used to transform the complex nonlinear system into a comparatively simple linear system.For parameter uncertainty of motion model,the controller is designed with mixed-sensitivity method based on H-infinity robust control theory.Simulation results show better robustness improved by this control method for roll stabilizing of AUV navigating near water surface.     

Parametric vibration of submerged floating tunnel tether under random excitation

For the study of the parametric vibration response of submerged floating tunnel tether under random excitation,a nonlinear random parametric vibration equation of coupled tether and tube of submerged floating tunnel is set up.Subsequently,vibration response of tether in the tether-tube system is analyzed by Monte Carlo method.It may be concluded that when the tube is subjected to zero-mean Gaussian white noise random excitation,the displacement and velocity root mean square responses of tether reach the peak if the circular frequency of tube doubles that of tether;the displacement and velocity root mean square responses of tether increase as the random excitation root mean square increases;owing to the damping force of water,the displacement and velocity root mean square responses of tether decrease rapidly compared with tether in air;increasing the damping of the tether or tube reduces the displacement and velocity root mean square responses of tether;the large-amplitude vibration of tether may be avoided by locating dampers on the tether or tube.     

The variation patterns and correlations of total phosphorus, organic phosphorus and phosphate in the Changjiang Estuary

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浅谈涉外海事仲裁协议的认定

仲裁亦称公断，是指争议的当事人在自愿的基础上，将争议提交非司法机构的第三者审理，并做出对争议各方有约束力裁决的一种解决争议的法律制度。以私法方面带有国际因素或涉外因素的争议为对象进行的仲裁，通常称为国际商事仲裁。其在狭义上不同于解决国家之间某一公法上的争端的国际仲裁、不同于为解决国家与企业或私人实体间争议所进行的跨国仲裁、也不同于解决一国范围内自然人、法人和其他组织之间争议包括行政仲裁在内的国内仲裁：广义上国际商事仲裁还包括跨国仲裁。国际商事仲裁主要包括国际贸易和国际海事仲裁。本文仅在狭义上讨论。按照我国现行法律规定，本文称涉外海事仲裁。     

Examination of empirical formulas for wave shoaling and breaking on steep slopes

Estimation of the wave height transformation of shoaling and breaking is essential for the nearshore hydrodynamics and the design of coastal structures. Many empirical formulas have been well recognized to the wave height transformation, but most of them were only applicable for gentle slopes. This paper reports the experimental results of wave shoaling and breaking over the steep slopes to examine the applicability of the previous empirical formulas. Two steep bottom slopes of 1/3 and 1/5, and one gentle slope of 1/10 were conducted in the present experiments. Experimental results show that the shoaling distance of steep slopes become short and the surface waves may be partially reflected from the steep bottom, thus the estimation of wave shoaling using the well-known previous formula did not conform completely to the experimental results. The previous empirical formulas for the wave breaking criteria were also examined, and the modified equations to the steep beaches were proposed in this work. A numerical model was finally adopted to calculate the wave height transformation in the surf zone by introducing the modified breaking index.     

Artificial upwelling induced by ocean currents —Theory and experiment

A submerged apparatus, which consists of a buoy, several horizontal contraction and expansion tubes (Venturi-type tubes) and a long pipe, is expected to be used to pump the subsurface sea-water (200–300 meter depth) containing abundant nutrients to surface layer (50–100 m) by the dynamic of ocean currents. i.e. an artificial upwelling without energy cost. A preliminary experiment and analysis are undertaken and shows that the capacity of pumping the nutrient-rich sea-water is worth to build a pilot prototype model.     

促熟措施对南美白对虾雌虾性腺成熟率的影响

南美白对虾(Penaeus vannamei)是北美和中南美洲普遍饲养的一种对虾,它不但具有生长迅速、对饲料蛋白质需求量低、出肉率高、离水存活时间长和易集约化养殖等优点,而且具有很强的抗病能力和对环境的适应能力。江苏省大丰市等地区的养殖试验表明,该对虾与中国对虾同池混养,在中国对虾陆续染病死亡的同时,该对虾却健壮活泼、生长旺盛,是值得我国大力推广的对虾养殖新品种。由于南美白对虾自然分布于西太平洋沿岸,我国无天然资源,因此,采取全人工育苗技术解决该虾苗种问题已成为当务之急。研究表明,该种雌虾在日常蓄养条件下性腺不会成熟,在驯养条件下其成熟也无规律(Yono,1990)。迄今为止,国内尚未见有南美白对虾池养雌虾促熟措施方面的报道。为此,我们在1995年工作基础上,于1996年3-5月,对池养南美白对虾雌虾进行了摘除眼柄、强化营养、控制光照等促熟对比试验,取得了较好的效果。     

Further evidence for non-reemergence of winter SST anomalies in the North Pacific eastern subtropical mode water area

Following our previous study (Sugimoto and Hanawa, 2005b), we further investigate the reason why reemergence of winter sea surface temperature anomalies does not occur in the North Pacific eastern subtropical mode water (NPESTMW) area, despite its occurrence in the North Pacific subtropical mode water and North Pacific central mode water areas. We use vertical temperature and salinity profiles of the World Ocean Circulation Experiment Hydrographic Program and Argo floats with high vertical and temporal resolution, together with heat flux data through the sea surface. We point out first that one of the causes for non-occurrence of reemergence is that the thickness of NPESTMW is very thin. In addition to this basic cause, two major reasons are found: a vigorous mixing in the lower portion of NPESTMW and less heat input from the atmosphere in the warming season. Since, in the lower portion of NPESTMW and deeper, the stratification is favorable for salt-finger type convection to occur compared with the other mode water areas, vigorous mixing takes place. This is confirmed by both a large Turner Angle there and the existence of staircase structures in vertical temperature and salinity profiles. From the viewpoint of heat input, the NPESTMW area gradually gains heat in the warming season compared with other mode water areas. As a result, NPESTMW cannot be capped so quickly by the shallow summer mixed layer, and water properties of NPESTMW are to be gradually modified, even in the upper portion.     

The application of cutting plus waterlogging to control Spartina alterniflora on saltmarshes in the Yangtze Estuary,China

Control and eradication of the exotic and invasive plant Spartina alterniflora within the Chongming Dongtan nature reserve, Shanghai, China, is vital for the management and conservation of the saltmarshes. A demonstration project was established using waterlogging and cutting to control this invasive species. Results from 2007 to 2008 showed that, although the managed waterlogging significantly reduced biomass and seed production of S. alterniflora at an early stage, the species subsequently showed rapid adaptation to the long-term waterlogging stress. Thus, managed waterlogging alone was insufficient for the effective eradication of S. alterniflora. However, managed waterlogging for around 3 months, combined with cutting the above-ground part of S. alterniflora at a key stage (flowering period in July), controlled and eradicated the plant successfully. Both the above-ground and below-ground parts of S. alterniflora were killed and the plants began to decompose after 3 months. Furthermore, there was no re-growth of the emergent part of S. alterniflora in the following years. However, once the impounded water was released restoring the natural hydrodynamic regime of the saltmarshes, the seeds and seedlings of S. alterniflora reinvaded the controlled site from the neighboring areas and the S. alterniflora community was re-established. Thus, after eradication of S. alterniflora, control measures should be maintained to prevent the re-establishment of S. alterniflora. The results of this demonstration project indicate a potentially useful and effective approach for the control and management of large-scale invasion by S. alterniflora on saltmarshes in the Yangtze Estuary, China.