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| 1 | Drift characteristics of green macroalgae in the Yellow Sea in 2008 and 2010显示文摘In order to investigate the aggregation mechanism of green macroalgae (Enteromorpha prolifera) on the Qingdao coastline,the macroalgal drift characteristics in the Yellow Sea during June and July in 2008 and 2010 were simulated using a three-dimensional wave-tide-circulation coupled model.In June 2008,the monthly-mean surface current flowed onshore and its direction was almost perpendicular to the Qingdao coastline,which was identified as the main reason for a huge accumulation of algae in the coastal waters off Qingdao.The current became parallel to the coastline in July 2008;this shift in current direction led to little accumulation of algae near Qingdao and thus relieved the environmental pressure on the Olympic sailing events.By using the coupled model,we predicted that there would be no serious algal accumulation at Qingdao in late June 2010,which was later confirmed by observations.This study demonstrated that the drift path of macroalgae near Qingdao is mainly controlled by the surface current,which is primarily driven by wind.Regional climate change is therefore one of the means by which physical processes affect marine ecosystems. | QIAO FangLi WANG GuanSuo LüXinGang DAI DeJun | 2011 | Chinese Science Bulletin2011，56，21： | 25 |
| 2 | Predicting the spread of nuclear radiation from the damaged Fukushima Nuclear Power Plant显示文摘Japan suffered a M9.0 earthquake and massive tsunami on March 11, 2011, which seriously damaged the Fukushima Nuclear Power Plant and caused a nuclear crisis. The spread of nuclear radiation from the power plant through the atmosphere and ocean was predicted with a short-term climate forecasting model and an ocean circulation model under some idealized assumptions. If nuclear matter were leaked in the near-ground layer of 992 hPa, the climate model results show that the nuclear radiation would cover North America 10 days after the initial leakage, with the concentration at the forefront dramatically reduced to 10 millionths of the initial model concentration at the source. The radiation would span Europe in 15 days and cover much of the Northern Hemisphere in 30 days. If the initial leakage was assumed to occur in the layer 5000-m above the ground, the radiation would cover Europe in 10 days and cover much of the Northern Hemisphere in 15 days. Moreover, under the assumption that the nuclear matter leaked in the 10000-m layer, the radiation would affect much of China after 10 days. The ocean circulation model indicates that the nuclear material would be slowly transported northeast of Fukushima and reach 150°E in 50 days, and the nuclear debris in the ocean would be confined to a narrow band. Compared with the spread in the ocean, the area affected by leaked nuclear radiation in the atmosphere would be very large. Atmospheric monitors in North America and Europe will be helpful for estimating the effect in China of any leaked nuclear material. | QIAO FangLi WANG GuanSuo ZHAO Wei ZHAO JieChen DAI DeJun SONG YaJuan SONG ZhenYa | 2011 | Chinese Science Bulletin2011，56，18： | 18 |
| 3 | A 2D-numerical modeling of the generation and propagation of internal solitary waves in the Luzon Strait显示文摘The wide presence of internal solitary waves (ISWs) in the northern South China Sea (SCS) has been confirmed by both Synthetic Aperture Radar (SAR) images and in situ observations.These ISWs are believed being generated over the varying topography in the Luzon Strait.They typically propagate westwards into the SCS with a diurnal or semidiurnal period.Their generation sites are,however,not yet solidly identified.To obtain a clear picture of the ISWs,we designed numerical experiments to analyze the generation and propagation of the ISWs in the Luzon Strait using a 2-dimensional non-hydrostatic model.The model current is forced by barotropic or baroclinic currents imposed at open boundaries.The experiments show that the tidal current serves as a kind of triggering force for the ISWs over the submarine ridges in the strait.Under the forcing of tidal currents,depressions are formed near the ridges.The ISWs then split from the depressions through a process different from lee-wave generation mechanism.The appearance of the ISWs is influenced by the strength and period of the forcing current: the ISWs are more likely to be generated by a stronger tidal current.That is why the ISWs in the Luzon Strait are frequently observed during spring tide.Compared with diurnal tidal current,the ISWs generated by semidiurnal tidal current with the same amplitude is much more energetic.It is partly because that the wave beams in diurnal frequency have a larger angle with the vertical direction,thus are more likely to be reflected by the topography slope.The impact of the Kuroshio to the ISWs is also analyzed by adding a vertical uniform or shear current at boundaries.A vertically uniform current may generate ISWs directly.On the other hand,a vertically shear current,which is more realistic to represent the Kuroshio branch,seems to have little influence on the generation process and radiating direction of the ISWs in the Luzon Strait. | WANG Gang QIAO Fangli DAI Dejun | 2010 | Acta Oceanologica Sinica2010，29，6： | 4 |
| 4 | The effects of vertical viscosity coefficients with different distribution characteristics on classical Ekman spiral structure显示文摘The classical Ekman theory tells us that the ocean surface current turns to the right(left) side of wind direction with 45° in the north(south) hemisphere,but the observation and research results show that the surface current deflexion angle is smaller than 45° in the Arctic and high latitude areas while larger than 45° in the low latitude areas.In order to explain these phenomena,a series of idealized numerical experiments are designed to investigate the influence of vertical viscosity coefficients with different vertical distribution characteristics on the classical and steady Ekman spiral structure.Results show that when the vertical viscosity coefficient decreases with water depth,the surface current deflexion angle is larger than 45°,whereas the angle is smaller than 45° when the vertical viscosity coefficient increases with water depth.So the different observed surface current deflexion angles in low latitude sea areas and the Arctic regions should be attributed to the different vertical distribution characteristics of vertical viscosity coefficients in the upper ocean.The flatness of the Ekman spiral is not equal to one and does not show regular behaviors for the numerical experiments with different distribution of vertical viscosity.However,the magnitudes and directions of volume transport of Ekman spirals are almost the same as the results of classical Ekman theory,i.e.,vertical viscosity coefficient distributions have no effect on the magnitudes and directions of volume transport. | MA HongYu QIAO FangLi DAI DeJun | 2014 | Science China Earth Sciences2014，57，4： | 2 |
| 5 | Response of Internal Waves to 2005 Typhoon Damrey over the Northwestern Shelf of the South China Sea显示文摘Continuous observation of sea water temperature and current was made at Wenchang Station(19°35′N,112°E) in 2005. The data collected indicate vigorous internal waves of both short periods and tidal and near-inertial periods. The temperature and current time series during 18-30 September were examined to describe the upper ocean internal wave field response to Typhoon Damrey(0518) . The strong wind associated with the typhoon,which passed over the sea area about 45 km south of Wenchang Station on 25 September,deepened the mixed layer depth remarkably. It decreased the mixed layer temperature while increasing the deep layer temperature,and intensified the near-inertial and high-frequency fluctuations of temperature and current. Power spectra of temperature and current time series indicate significant deviations from those obtained by using the deep ocean internal wave models characterized by a power law. The frequency spectra were dominated by three energetic bands:around the inertial frequency(7.75× 10-6 Hz) ,tidal frequencies(1.0×10-5 to 2.4×10-5 Hz) ,and between 1.4×10-4 and 8.3×10-4 Hz. Dividing the field data into three phases(before,during and after the typhoon) ,we found that the typhoon enhanced the kinetic energy in nearly all the frequency bands,especially in the surface water. The passage of Damrey made a major contribution to the horizontal kinetic energy of the total surface current variances. The vertical energy density distribution,with its peak value at the surface,was an indication that the energy injected by the strong wind into the surface current could penetrate downward to the thermocline. | WANG Gang QIAO Fangli HOU Yijun DAI Dejun LIN Min ZHANG Qilong WANG Gang YIN Baoshu | 2008 | Journal of Ocean University of China2008，7，3： | 2 |
| 6 | Scattering Process of Internal Waves Propagating over a Subcritical Strait Slope onto a Shelf Region显示文摘The scattering process, which means the redistribution of energy fluy in modenumber space, is analyzed for internal waves propagating from the abyssal ocean onto a subcritical strait slope and then a shelf region. In light of Wunsch's work, the waves are analytically expressed as superimposition of eigensolutions. Two parameters have evident effects on the distribution of energy flux in the shelf region: one is the ratio of water depth in the shelf region to that in the abyssal ocean and the other is the ratio of the slope of the internal tide rays to the topographic slope. Generally, there are two patterns of energy flux distribution: the energy flux is focused around one modenumber or focused around two modenumbers. In any case, the range of modenumbers where energy flux is distributed is narrow. | DAI Dejun WANG Wei QIAO Fangli YUAN Yeli | 2005 | Journal of Ocean University of China2005，4，4： | 2 |
| 7 | Solutions for Supporting Qos in Database in Web Application servers显示文摘 | Lu Jianbo Dai Guanzhong Mu Dejun | 2012 | International Journal of Digital Content Technology and Its Applications2012，6，11： | 1 |
| 8 | The Equilibrium Range of Wind Wave Spectra: an Explanation Based on White Noise显示文摘Laboratory experiments and field observations show that the equilibrium range of wind wave spectra presents a – 4 power law when it is scaled properly. This feature has been attributed to energy balance in spectral space by many researchers. In this paper we point out that white noise on an oscillation system can also lead to a similar inverse power law in the corresponding displacement spectrum, implying that the – 4 power law for the equilibrium range of wind wave spectra may probably only reflect the randomicity of the wind waves rather than any other dynamical processes in physical space. This explanation may shed light on the mechanism of other physical processes with spectra also showing an inverse power law, such as isotropic turbulence, internal waves, etc. | DAI Dejun WANG Wei QIAO Fangli YUAN Yeli | 2007 | Journal of Ocean University of China2007，6，4： | 1 |
| 9 | Investigating the Effects of the Driving Cycle and Penetration of Electric Vehicles on Technical and Environmental Characteristics of the Hybrid Energy System Considering Uncertainties显示文摘Electric vehicles(EVs)have received special consideration from modern society over the past several years.Although EVs are a fine example of environmentally friendly technology and have many advantages,they relatively increase the electricity demand upon a power grid as well.Therefore,their negative impact on busvoltage and line losses should be analyzed.In this study,the effect of EV loads and their penetration on bus voltage and line losses of an IEEE-33 bussystem has been examined via two scenarios.It is important to mention that the effect of EVs on the rate of air pollution,produced by fossil fuel electricity generators,has been investigated throughout the study.Also,the key role of demand response programs in the reduction of EVs’negative effects on the grid has also been discussed in the last scenario.Generally,the simulation of this paper provides a novel and wider perspective on EVs and their effect on grids and environmental pollution. | Jiusong Chen Dejun Miao Yizong Dai Mojtaba Ghadamyari | 2022 | Energy Engineering2022，119，5： | 0 |
| 10 | Can Langmuir Circulations Solve the Problem of Insufficient Upper-Ocean Mixing?显示文摘Insufficient vertical mixing in the upper ocean during summer is a common problem of oceanic circulation and climate models.The turbulence associated with non-breaking waves is widely believed to effectively solve this problem.In many studies,non-breaking surface wave processes are attributed to the effects of Langmuir circulations(LCs).In the present work,the influences of LCs on the upper-ocean thermal structure are examined by using one-and three-dimensional ocean circulation,as well as climate,models.The results indicated that the effect of vertical mixing enhanced by LCs is limited to the upper ocean.The models evaluated,including those considering LC effects alone and the combined effects of LCs and wave breaking,failed to produce a reasonable summertime thermocline,resulting in a large cold bias in the subsurface layer.Therefore,while they can slightly reduce the biases of mixed layer depths and sea surface temperatures in models,LCs are insufficient to solve the problem of insufficient vertical mixing.Moreover,restriction of non-breaking surface wave-induced processes in LCs may be questionable. | HUANG Chuanjiang QIAO Fangli DAI Dejun | 2020 | Journal of Ocean University of China2020，19，4： | 0 |
| 11 | Estimation of vertical diffusion coefficient based on a onedimensional temperature diffusion equation with an inverse method显示文摘Diapycnal mixing is important in oceanic circulation. An inverse method in which a semi-explicit scheme is applied to discretize the one-dimensional temperature diffusion equation is established to estimate the vertical temperature diffusion coefficient based on the observed temperature profiles. The sensitivity of the inverse model in the idealized and actual conditions is tested in detail. It can be found that this inverse model has high feasibility under multiple situations ensuring the stability of the inverse model, and can be considered as an efficient way to estimate the temperature diffusion coefficient in the weak current regions of the ocean. Here, the hydrographic profiles from Argo floats are used to estimate the temporal and spatial distribution of the vertical mixing in the north central Pacific based on this inverse method. It is further found that the vertical mixing in the upper ocean displays a distinct seasonal variation with the amplitude decreasing with depth, and the vertical mixing over rough topography is stronger than that over smooth topography. It is suggested that the high-resolution profiles from Argo floats and a more reasonable design of the inverse scheme will serve to understand mixing processes. | LIANG Hui ZHAO Wei DAI Dejun ZHANG Jun | 2014 | Acta Oceanologica Sinica2014，33，5： | 0 |
| 12 | Eigen solutions of internal waves over subcritical topography显示文摘Diapycnal mixing plays an important role in the ocean circulation.Internal waves are a kind of bridge relating the diapycnal mixing to external sources of mechanical energy.Difficulty in obtaining eigen solutions of internal waves over curved topography is a limitation for further theoretical study on the generation problem and scattering process.In this study,a kind of transform method is put forward to derive the eigen solutions of internal waves over subcritical topography in twodimensional and linear framework.The transform converts the curved topography in physical space to flat bottom in transform space while the governing equation of internal waves is still hyperbolic if proper transform function is selected.Thus,one can obtain eigen solutions of internal waves in the transform space.Several examples of transform functions,which convert the linear slope,the convex slope,and the concave slope to flat bottom,and the corresponding eigen solutions are illustrated.A method,using a polynomial to approximate the transform function and least squares method to estimate the undetermined coefficients in the polynomial,is introduced to calculate the approximate expression of the transform function for the given subcritical topography. | DAI Dejun WANG Wei ZHANG Qinghua QIAO Fangli YUAN Yeli | 2011 | Acta Oceanologica Sinica2011，30，2： | 0 |
| 13 | Three dimensional simulation of internal wave attractors in the Luzon Strait显示文摘Internal waves propagate along wave beams that are inclined with respect to the horizontal plane. It is conjectured that the internal waves generated in the Luzon Strait may be confined between the double ridges in the strait and concentrate to a closed trajectory, the so-called internal wave attractor, due to the reflection of wave beams from the lateral boundaries, sea surface and bottom. This work carried out two experiments using a three dimensional non-hydrostatic general circulation model, MITgcm, to investigate the possibility that the ridges in the Luzon Strait allows for internal wave attractors. Baroclinic current in both of the experiments demonstrate the forming of ring-like patterns in some section around 20° and 21°N, indicating that the development of the internal wave attractors are allowed in the Luzon Strait. The different resolutions and initial conditions in the two experiments also reveal that the internal-wave-attractor phenomenon is robust in this region. | WANG Gang ZHENG Quanan LIN Min DAI Dejun QIAO Fangli | 2015 | Acta Oceanologica Sinica2015，34，11： | 0 |
| 14 | A possible generation mechanism of the strong current over the northwestern shelf of the South China Sea显示文摘Continuous observation in late April 2005 on the northwestern shelf of the South China Sea reveals vigorous strong currents,the maximum velocity of which exceeds 3.8 m/s.The strong currents occurred around spring tide period,when the internal tide waves were also expected to be vigorous.Analysis shows that the major peaks of the current power spectrum are in low frequency band.Using a numerical method applied to the actual ocean stratification,we find that the amplitude profiles of the strong current are similar to that of the currents induced by some low-mode internal waves (at diurnal or semi-diurnal frequency).It indicates that the temporal and spatial features of strong currents were possibly induced by low frequency internal waves. | WANG Gang QIAO Fangli DAI Dejun HOU Yijun | 2011 | Acta Oceanologica Sinica2011，30，3： | 0 |
| 15 | An AP-DE Algorithm Based on Multi-step Gradient Method显示文摘Aim to improve the convergence of the adaptive filtering, based on the multi-step gradient method, a new affine pro jection algorithm with direction error is presented. The statistical behavior of the proposed algorithm is analyzed. The deterministic recursive equations for the weight error and for the Mean-square error(MSE) are derived in the weight update direction of the adaptive filtering. The steady-state MSE is also obtained.Simulation results show that the proposed algorithm improve the adaptive filtering convergence and corroborate the theoretical analytical results. | DAI Dameng MU Dejun | 2016 | Chinese Journal of Electronics2016，25，1： | 0 |
| 16 | Using Combinational Logic Function to Watermark IP Based on FPGA显示文摘In the field of digital circuit design, the extensive applications of reusable intellectual property (IP) simplify the design procedure based on very large scale field programmable gate array (FPGA), and shorten the time to market (TTM). However, the flexibility of reusable IP makes itself easy to be stolen and illegally distributed by intruders. The protection method proposed in this paper maps IP owner’s signature to combinational logic functions, and then implements these functions into unused lookup tables (LUTs) in the design based on FPGA, which can be used as a strong proof of IP’s ownership. The related experiment results show that this protection method has favorable characteristics such as low overhead, few effects on performance, and high security. | MIAO Sheng DAI Guanzhong MU Dejun LI Meifeng | 2006 | Wuhan University Journal of Natural Sciences2006，11，6： | 0 |
| 17 | An Algorithm for Bus Trajectory Extraction Based on Incomplete Data Source显示文摘 | DAI Dameng MU Dejun | 2012 | Chinese Journal of Electronics2012，21，4： | 0 |
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