Directional Spectrum of Wind Waves： Part I-Model and Derivation 免费阅读 下载全文 A new model on the directional spectrum of wind waves for deep water is proposed based on the statistics of wind waves. This model contains three parameters: the wave age, the inverse spectral bandwidth and the local spectral-peak angular frequency. The inverse spectral bandwidth is a robust parameter for describing the spectral steepness of wind waves. Using the inverse spectral bandwidth parameter, the proposed model can well describe various observations obtained from the open ocean and laboratory tank.Directional Spectrum of Wind Waves： Part Ⅱ-Comparison and Confirmation 免费阅读 下载全文 A model on the directional frequency spectrum of wind waves for deep water is introduced. The comparisons of the proposed model with other existing models show that the proposed model is very close to the JONSWAP model and DHH model for describing the developing waves under the normal spectral bandwidth, and has a better description for the transition of the unidirectional spectrum from ω^-4 to ω^-5 at a position around 3ωp, i.e., three time the peak frequency. Comparisons also show that the proposed model describes closely both field data measured by a four-frequency radar and a laser-optical sensor, and laboratory data measured by a laser slope gauge and an imaging optical method. The comparisons further demonstrate that the inverse spectral bandwidth as a new wave parameter is robust for describing the spectral steepness. Finally, the formula on the local spectral-peak angular frequency is confirmed using the observed two-dimensional spectra.A Numerical Study of Water Circulation in A Thermally Stratified Embayment 免费阅读 下载全文 Princeton Ocean Model is used to study the response of Jervis Bay, NSW, Australia, to the local wind and remote shelf coastal trapped wave (CTW) forcings in summer seasons when the water column is stratified by the water temperature.The study has revealed that the response of bay to the wind forcing is the generation of the wind driven currents and the internal Kelvin waves (IKW). However, both temperature and flow sub-inertial oscillations in the bay are weaker than those from the observations and the correlation between the modeled and observed low frequency currents is low. In response to the forcing of CTWs on the adjacent shelf, IKWs are also established in the bay and amplitudes of sub-inertial oscillations of temperature and currents agree better with the observations. It can be concluded that sub-inertial baroelinic flows in the bay is dominantly forced by remote CTW on the shelf adjacent to Jervis Bay during thermally stratified summer seasons.The Sediment and Hydrographic Characteristics of Three Horseshoe Crab Nursery Beaches in Hong Kong 免费阅读 下载全文 Horseshoe crab juveniles have been recorded from sand and sandy-mud nursery beaches at Pak Nai (western New Territories ), San Tau and Shui Hau (Lantau Island), Hofig Kong. In order to provide a better understanding of these beaches and to identify those plausible factors which have made them preferred by spawning horseshoe crabs, environmental parameters, including temperature, salinity, pH and dissolved oxygen content of the water, and particle size distribution and organic matter content of the sediments at the three sites, were determined and compared. The hydrographic and sediment data obtained for the three study sites have revealed some common environmental features. The three nursery beaches are relatively remote, and far (in Hong Kong terms) from urbanized and densely populated areas. The beaches are generally well sheltered from strong wave action and inundated regularly by estuarine waters. Horseshoe crab adults tend to select these beaches for spawning as their protected features ensures the laid eggs are less likely to be washed out of the sand, and hatched juveniles can feed on the meiofauna and grow. Sediments of the three beaches largely comprise medium-sized sand particles and are moderately sorted, suggesting medium porosity and good water permeability. Such a sand type, with the generally high oxygen levels in incursing waters, may help create a well-oxygenated micro-environment for the normal development of horseshoe crab eggs, larvae and juveniles. Lantau Island beaches at San Tau and Shui Hau are relatively free from organic pollution, as reflected in generally high dissolved oxygen level, and low BOD5 and ammonia nitrogen values. Pak Nai is, however, more polluted.Rheological Properties and Structural Changes in Different Sections of Boiled Abalone Meat 免费阅读 下载全文 Changes in tissue structures, rheological properties of cross- and vertical section boiled abalone meat were studied in relation to boiling time. The adductor muscle of abalone Haliotis discus which was removed from the shell, was boiled for 1, 2, and 3 h, respectively. Then it was cut up and separated into cross- and vertical section meat. When observed by a light microscope and a scanning electron microscope, structural changes in the myofibrils were greatest in the cross section meat compared with the vertical section meat. When boiling time was increased from 1 h to 3 h, the instantaneous modulus E0 and rupture strength of both section meat decreased gradually with increased boiling time, and no significant differences were observed between these two section meat for the same boiling time. When boiled for 1 h, the relaxation time of cross section meat was much longer than that of vertical section meat. There were no significant changes in the relaxation time of vertical section for different boiling time, but the relaxation time of cross section meat was reduced gradually with increasing boiling time. These results confirmed that the difference in rheological properties between the cross- and vertical section meat was mainly due to the denaturation level of myofibrils when heated for 1 h, as well as due to the changes in the amount of denatured proteins, and the manner in which the inner denatured protein components weve exchanged after boiling time was increased from 1 h to 3 h.Diversity of Bacteria Isolated from Crustacea Larvae and Their Rearing Water 免费阅读 下载全文 The bacteria in the genus Vibrio are heterothrophic, which exist in the larval rearing water of Crustacea and often show diverse pathogenicities to marine animals. In order to assess the bacterial diversity associated with Crustacean seed production, 32 strains were isolated from black tiger shrimp ( Penaeus monodon ) and mangrove crab (Scylla paramamosain ) larvae and their rearing-water and characterized using biochemical and molecular approaches. Two or more genotypically different species were identified. The vibriosis of black tiger shrimp was caused by V. harveyi, V.alginolyticus and Vibrio spp.predominantly, while that of crab by V. harveyi and V. alginolyticus only.A New Pullulan-Producing Yeast and Medium Optimization for Its Exopolysaccharide Production 免费阅读 下载全文 Yeast strain Y68 producing high level of pullulan was isolated from the phyton collected in Toulouse, France.This strain was identified to be Rhodotorula bacarum by BIOLOG analysis. This is the first report that pullulan was produced by Rhodotorula bacarum. The optimal medium (gL^-1) for pullulan production by this strain was 80 glucose, 20 soybean cake hydrolysate, 5K2HPO4, 1NaCl, 0.2MgSO4·7H2O, 0.6 (NH4)2SO4, pH7.0. Under this condition, 54gL^-1 pullulan was produced within 60 h at 30℃. Pullulan is a better starting material for producing marine prodrugs.Isolation of Protoplasts from Undaria pinnatifida by Alginate Lyase Digestion 免费阅读 下载全文 The aim of this study is to isolate protoplasts from Undaria pinnatifida. Protoplasts of the alga were isolated enzymatically by using alginate lyase, which was prepared by fermenting culture of a strain Vibrio sp. 510. Monofacterial method was applied for optimizing digestion condition. The optimum condition for protoplast preparation is enzymatic digestionat 28℃ for 2 h using alginate lyase at the concentration of 213.36 U(8 mL) every 0.5g fresh thalline with Nacl 50 and at theshaking speed of 150rmin^-1 during digestion. The protoplast yield can reach 2.62±0.09 million per 0.5 g fresh leave under the optimum condition. The enzyme activity is inhibited by Ca^2+ and slightly enhanced by Fe^2+ and Mn^2+ at concentrations of 0.05, 0.08 and 0.10mol L^-1.Studies on the Effects of Polyaspartate Protease Fertilizer Enhancer in the Absorptions of Soil Nutrition and the Enzynmtic Activities of Crops 免费阅读 下载全文 The effects of polyaspartate protease fertilizer enhancer, made from oyster shell proteins, on the absorption of soil nutrition and the enzymatic activities of crops were studied. It has been found that the enhancer contributes 30%, 50% and 50% augmentation of nitrogen (N), phosphate (P) and potassium (K) absorption respectively and about 20% of nitrate reductase and peroxide enzyme activities of crops. These results show that polyaspartate protease fertilizer enhancer could improve significantly the absorption and utilization efficiencies of soil nutrition and the activities of nitrate reductase and peroxide enzyme of crops, thus elevating the utilization rates of chemical fertilizers to a certain extent.Fatty Acid Composition Analyses of the DCMU Resistant Mutants of Nannochloropsis oculata （ Eustigmatophyceae ） 免费阅读 下载全文 Ultraviolet mutagenesis was applied to Nannochloropsis oculata and three mutants resistant to 3-(3, 4-dichlorophenyl)-l, 1-dimethylurea (DCMU) were isolated. The cellular chlorophyll a and total lipid content of the wild are higher in the medium supplemented with DCMU than in the control without DCMU. Without DCMU, the growth rates and chlorophyll a contents of the mutants are similar to those of the wild. Significant changes of fatty acid content and composition have occurred in DCMU-resistant mutants growing in the medium supplemented with DCMU. The total lipid, palmitic acid (16:0), palmitoleic acid ( 1 6:1ω9) and oleic ( 18:1ω09 ) contents decrease significantly, while the vaccenic acid ( 18:1ω11 ) increases significantly and the EPA content of dried powder increases slightly in the mutants. The study may provide a basis to improve EPA content in Nannochloropsis oculata in the future.Preparation of Carboxymethyl Sulfochitosans with Differentially Substituted Regions 免费阅读 下载全文 Five kinds of carboxymethyl sulfochitosans with different regions such as N-carboxymethyl-O-sulfochitosan, O-car-boxymethyl-N-sulfochitosan, O-carboxymethyl chitosan sulfate, N-carboxymethyl chitosan-6-sulfate, and N, O-carboxymethyl-N, O-sulfochitosan were prepared respectively by using differential carboxymethylation and sulfation methods, and their IR spectrum and ^13C-NMR spectrum were measured.Effects of Sodium, Nitrate and Sodium Acetate Concentrations on the Growth and Fatty Acid Composition of Brachiomonas submarina 免费阅读 下载全文 One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate was chosen as the organic nutrient to test the combined effects of organic and inorganic solutions on the growth and fatty acid composition of Brachiomonas submarina. The best growth rates were achieved at 3 mmol L^-1 CH3COONa and 0.88 mmol L^-1 NaNO3 in heterotrophic condition, and 4 mmol L^-1 CH3COONa and 3.52 mmol L^-1 NaNO3 in mixotrophic condition. The differences between fatty acid contents were significant. The total polyunsaturated fatty acids (T. P. U. F. As) varied from 55.79% to 67.72% in heteritrophic growth and from 52.39% to 65.55 % in mixotrophic growth. It is concluded that CH3COONa and NaNO3 at 3 mmol L^-1 and 3.52 mmol L^-1 should respectively be used in order to achieve the highest growth rate and fatty acid content.Advances in the Marine Photochemistry of Some Important Transition Metal Elements 免费阅读 下载全文 Marine inorganic photochemistry, as one of the important branches of marine chemistry, is significantly connected with marine biology, marine ecology, marine geochemistry and marine environment, and plays an important role in the development of marine sciences. To date, lots of investigations in the field have been conducted home and abroad. As for the following development of marine inorganic photochemistry, it is greatly of significance to summarize these research works. This paper detailedly summarizes the present research progress in the photochemistry of Fe, Mn and Cu, with an emphasis on investigations on photochemical processes which could affect existing forms of these metal elements in seawater.The problems and shortcomings in the study field are pointed out and some suggestions for the future study are put forward.ROV Based Underwater Blurred Image Restoration 免费阅读 下载全文 In this paper, we present a method of ROV based image processing to restore underwater blurry images from the theory of light and image transmission in the sea. Computer is used to simulate the maximum detection range of the ROV under different water body conditions. The receiving irradiance of the video camera at different detection ranges is also calculated. The ROV‘s detection performance under different water body conditions is given by simulation. We restore the underwater blurry images using the Wiener filter based on the simulation. The Wiener filter is shown to be a simple useful method for underwater image restoration in the ROV underwater experiments. We also present examples of restored images of an underwater standard target taken by the video camera in these experiments.Development and Potential of Space-Borne Doppler Wind Lidar 免费阅读 下载全文 The advantage of lidar over other wind sensors is presented in this paper. With more than 20 years research, the development of the space-borne wind lidar is reviewed. Longer-term investigation has made many technologies suitable for the wind lidar measurement from an orbital platform become mature. However, there are still some problems to be solved.In order to obtain the optimal performance in wind detection,al space-borne wind lidar system on computer as developed bygreat importance is being attached to the simulation of a virtual space-borne wind lidar system on computer as developed by NASA and ESA.Numerical Simulation on the Extraction of Modal Back-Scattering Matrix from Reverberation Data for High Frequency Cases 免费阅读 下载全文 The modal back-scattering matrix can be extracted from reverberation data. For high frequency cases the ‘window smoothed‘ processing has been proposed by E. C. Shang. T. F. Gao and D. J. Tang (2002) to extract the ‘window averaged‘ back-scattering matrix. It is pointed out in this paper that in order to inverse the ‘window averaged‘ back-scattering matrix by changing the source depth data we have to assume that the matrix is not related to the source depth, and the numerical simulation on the question has been conducted.Numerical Simulation of 3-D Wave Crests 免费阅读 下载全文 A clear definition of 3-D wave c-rest and a description of the procedures to detect the boundary of wave crest are presented in the paper. By using random wave theory and directional wave spectrum, a MATLAB-platformed program is designed to simulate random wave crests for various directional spectral conditions in deep water. Statistics of wave crests with different directional spreading parameters and different directional functions are obtained and discussed.Nonlinear Fitting Method of Long-Term Distributions for Statistical Analysis of Extreme Negative Surge Elevations 免费阅读 下载全文 Hydrologic frequency analysis plays an important role in coastal and ocean engineering for structural design and disaster prevention in coastal areas. This paper proposes a Nonlinear Least Squares Method (NLSM), which estimates the three unknown parameters of the Weibull distribution simultaneously by an iteration method. Statistical test shows that the NLSM fits each data sample well. The effects of different parameter-fitting methods, distribution models, and threshold values are also discussed in the statistical analysis of storm set-down elevation. The best-fitting probability distribution is given and the corresponding return values are estimated for engineering design.Distributions of Inorganic Nutrients in the Bohai Sea of China 免费阅读 下载全文 To study the contents and distribution of inorganic nutrients in the Bohai Sea of China, two cruise surveys were undertaken in August (summer) 2000 and January (winter) 2001, respectively. A total of 595 water samples were collected from 91 stations and five nutrients, i.e., nitrate, nitrite, ammonia, phosphate and silicate, were analyzed for each sample.The results show that the average concentration of dissolved inorganic nitrogen (DIN) in the Bohai Sea in winter (6.529 μmol L^-1 )is significantly higher than that in summer (3.717μmol L^-1 ). The phosphorus concentration in winter (0.660μmol L^-1) is alsosignificantly higher than that in summer (0.329μmol L^-1). Mean silicate concentration in winter (7.858μmol L^-1) is, however, not significantly different from that in summer (7.200μmol L^-1). Nutrients also vary considerably in different areas in Bohai Sea. DIN concentration in the Laizhou Bay (4.444μmol L^-1), for example, is significantly higher than those in the Bohai Bay (2.270μmol L^-1) and Bohai Strait (2.431μmol L^-1 ), which !s caused by the discharge of large amounts of nitrogen into Laizhou Bay via Yellow River. The nutrients show different vertical distribution patterns. In summer, nutrients in bottom layer are generally richer than those in surface and middle layers. In winter, however, nutrients are not significantly different in different layers. Compared with historic data, DIN contents have increased continually since the early 1980s. Based on atomic ratios of different nutrients, nitrogen is still the limiting factor for algal growth in the Bohai Sea.