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Siltation and radiocesium pollution of small lakes in different catchment types far from the Fukushima Daiichi nuclear power plant accident site

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International Soil and Water Conservation Research 2020年第1期8卷 56-65页

作者： Mikhail Komissarov shin-ichiro Ogura Ufa Institute of Biology Russian Academy of SciencesPr.Oktyabrya 69Ufa450054Russia Graduate School of Agricultural Science Tohoku University232-3 YomogitaNaruko-onsenOsaki989-6711Japan

The Fukushima Daiichi nuclear power plant accident caused radioactive pollution in northeastern Honshu Island,*** study examined the influence of snowmelt and rainfall on soil erosion pro-cesses and siltation of small lakes in Miyagi Prefecture(150 km northwest of the power plant).Two sets of slopes and lakes,respectively in pasture and forest catchments,were *** thickness,soil infiltration,surface runoff volume,soil and sediment physicochemical properties,Cs concentration of precipitation,meltwater,and rainwater,and lake siltation rates were *** total radioactive Cs content in precipitation was 0.7-7.4 Bq·L^-1 and was below the Japanese standard(10 Bq·L^-1).Total radioactive Cs was at the allowable level in water flowing down the pasture catchment slope(0.1-9.2 Bq·L^-1)during snowmelt and rainfall,as well as in pasture(0.9-8.8 Bq·L^-1)and forest(0.7-5.2 Bq·L^-1)catchment lake *** was no soil erosion(surface runoff)in the forest *** losses in the pasture catchment were 23 due to rainfall and 9 kg ha^-1 yr^-1 following spring *** snow-melt,a 0.5 and 0.2 mm thick layer of silt was deposited in pasture and forest catchment lakes,respec-tively,and 1.4 and 0.6 mm were deposited during the rainfall *** siltation rates were 1.9 and 0.8 mm·yr^-1 for pasture and forest catchment lakes,*** upper layer of lake bottom sedi-ments is represented mainly by silt fractions(2-50μm),with high organic matter(4.0-5.7%)and radiocesium(1100-1600 kg·ha^-1)contents.

关键词： Fukushima Daiichi Radiocesium Siltation Suspended sediment Waterbodies Water turbidity

Effect of Gas Bubbling Filtration Treatment on Microporosity Variation in A356 Aluminium Alloy

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Acta Metallurgica Sinica(English Letters) 2016年第7期29卷 638-646页

作者： Choongdo Lee Taeil So Kwangseon shin Department of Metallurgical & Materials Engineering Inha Technical College Magnesium Technology Innovation Center Department of Materials Science and EngineeringSeoul National University

In the present study, the contribution of the gas bubbling filtration （GBF） process to the microporosity variation, microstructural characteristics and tensile properties of A356 aluminium alloy was investigated. The test specimens were fabricated through gravity casting in terms of the process variables： the degassing time, the impeller rotation and the aperture size of gas inlet hole. The density measurement and scanning electron microscope fractography analyses were conducted to evaluate the variation of the volumetric porosity and fractographic porosity with the GBF process, respec- tively. The fractographic porosity of the specimens can be minimised under specific GBF conditions in terms of the buoyant velocity and the absorbing capacity of gas bubbles, the inclusion of oxide films, whereas the volumetric porosity can be wholly reduced on the lapse of degassing time. The ultimate tensile strength （UTS） and elongation at optimal conditions were improved to approximately 30 MPa and 1.5% compared with no GBF treatment. Even though an extension of the degassing time and/or excessive stirring action of the melt may induce the inclusion of bifilm oxides and the increase of fractographic porosity, the tensile properties of over-treated specimens were maintained to a level which is similar to those that did not undergo GBF treatment due to the grain refinement accompanying with the GBF process. In addition, the defect susceptibility of UTS and elongation to microporosity variation could be remarkably improved at an optimal GBF condition.

关键词： Aluminium alloy Microporosity Gas bubbling filtration process (GBF) Tensile property

EXPLICIT BOUNDS OF EIGENVALUES FOR STIFFNESS MATRICES BY QUADRATIC HIERARCHICAL BASIS METHOD)

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Journal of Computational Mathematics 2003年第2期21卷 113-124页

作者： Sang Dong KIM Byeong Chun shin Department of Mathematics Kyungpook National UniversityTaegu 702-701KoreaDepartment of MathematicsChonnam National UniversityGwangju 500-757Korea

The bounds for the eigenvalues of the stiffness matrices in the finite element discretization corresponding to Lu := - u' with zero boundary conditions by quadratic hierarchical basis are shown explicitly. The condition number of the resulting system behaves like O(1/h) where h is the mesh size. We also analyze a main diagonal preconditioner of the stiffness matrix which reduces the condition number of the preconditioned system to O(1).

关键词： hierarchical basis multilevel

CHEBYSHEV WEIGHTED NORM LEAST-SQUARES SPECTRAL METHODS FOR THE ELLIPTIC PROBLEM

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Journal of Computational Mathematics 2006年第4期24卷 451-462页

作者： Sang Dong Kim Byeong Chun shin Department of Mathematics Kyungpook National University Taegu 702-701 Korea Department of Mathematics Chonnam National University Kwangju 500-757 Korea

We develop and analyze a first-order system least-squares spectral method for the second-order elhptic boundary value problem with variable coefficients. We first analyze the Chebyshev weighted norm least-squares functional defined by the sum of the Lw^2- and Hw^-1- norm of the residual equations and then we eplace the negative norm by the discrete negative norm and analyze the discrete Chebyshev weighted least-squares method. The spectral convergence is derived for the proposed method. We also present various numerical experiments. The Legendre weighted least-squares method can be easily developed by following this paper.

关键词： Least-squares methods Spectral method Negative norm.

Photocatalytic decomposition of mobile-source related pollutants using a continuous-flow reactor

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Journal of Environmental Sciences 2010年第3期22卷 460-466页

作者： Wan-Kuen Jo Seung-Ho shin Department of Environmental Engineering Kyungpook National University

This study evaluated the application of a continuous-flow photocatalytic reactor for the control of two mobile-derived pollutants, methyl-tertiary butyl ether （MTBE） and naphthalene, present at in-vehicle levels. Variables tested for this study included the hydraulic diameter （HD）, stream flow rate （SFR）, relative humidity （RH）, and feeding type （FT）. The fixed parameters included contaminant concentration, ultraviolet light source, and the weight of TiO2. In all experimental conditions the adsorption process reached equilibrium within 30 to 180 min for the target compounds, and the outlet concentrations of the photocatalytic oxidation （PCO） reactor while operating reached a steady state within 60 to 180 min. The degradation of the target compounds was dependent on RH, HD, FT, or SFR. The PCO system exhibited high degradation （up to nearly 100% for certain conditions） and mineralization efficiencies of target compounds, suggesting that this system can effiectively be employed to improve indoor air quality. Moreover, it was confirmed that trichloroethylene at urban-ambient level also could enhance the degradation efficiency of naphthalene when applying the PCO technology inside vehicles.

关键词： in-vehicle level methyl-tertiary butyl ether naphthalene trichloroethylene

Effect of CaF2 content in refining slag on formation behavior of spinel inclusion in Ni-Cr-V-alloyed special steel

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Journal of Iron and Steel Research International 2018年第2期25卷 157-163页

作者： Jae-hong shin Joo-hyun Park Department of Materials Engineering Hanyang UniversityAnsan 426-791 Korea

The influence of CaF2 content on the formation behavior of spinel inclusions in the Ni-Cr-V-alloyed special steel was presented. The spinel was not formed at CaF2 content lower than 10 wt%. However, it was formed at early stage when the CaF2 content was greater than 30 wt%, followed by a modification to the aluminosilicate-type inclusions. Because the slag was saturated by MgO, the activity of MgO was unity irrespective of CaF2 content in the slag. Thus, Mg was transferred from slag to metal phase. Mg transferred to molten steel reacted with Al2O3-rich inclusions to form ***2O3 spinel. However, the spinel inclusion was modified to aluminosilicate-type inclusions by the reaction with Si and Ca transferred from slag to molten steel about 2-3 h later.

关键词： Spinel inclusion Refining slag CaF2 content Ni-Cr-V-alloyed special steel

Hybrid Broadcast for the Video—on—Demand Service

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Journal of Computer Science & Technology 2002年第4期17卷 397-410页

作者：马华东 KangG.shin CollegeofComputerScienceandTechnolgoy BeijingUniversityofPostandTececommunicationsBeijing100876P.R.China Real－TimeComputingLab EECSDepartmentTheUniversityofMichiganAnnArborMI4

Multicast offers an efficient means of distributing video contents/programs to multiple clients by batching their requests and then having them share a server's video *** customers' requests is either client-initiated or *** anvanced client-initiated video multicasts are implemented by *** broadcast,a typical server-initiated approach,can be entirety-based or *** paper focuses on the performance of the VoD service for popular ***,we analyze the limitation of conventional patching when the customer request rate is ***,By combining the advantages of each of the two broadcast schemes,we propose a hybrid broadcast scheme for popular videos ,which not only lowers the serviec latency but also improves clients' interactivity by using an active buffering technique ,This is shown to be a good compromise for both lowering service latency and improving the VCR-like interactivity.

关键词： quality-of-service interactivity scheduling video-on-demand broadcast, multicast

Encoding-based brain-computer interface controlled by non-motor area of rat brain

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Science China(Life Sciences) 2011年第9期54卷 841-853页

作者： shin Hyung-Cheul Department of Physiology College of MedicineHallym UniversityChuncheon 200-702Republic of Korea

As the needs of disabled patients are increasingly recognized in society, researchers have begun to use single neuron activity to construct brain-computer interfaces （BCI）, designed to facilitate the daily lives of individuals with physical disabilities. BCI systems typically allow users to control computer programs or external devices via signals produced in the motor or pre-motor areas of the brain, rather than producing actual motor movements. However, impairments in these brain areas can hinder the application of BCI. The current paper demonstrates the feasibility of a one-dimensional （ID） machine controlled by rat prefrontal cortex （PFC） neurons using an encoding method. In this novel system, rats are able to quench thirst by varying neuronal firing rate in the PFC to manipulate a water dish that can rotate in 1 D. The results revealed that control commands generated by an appropriate firing frequency in rat PFC exhibited performance improvements with practice, indicated by increasing water-drinking duration and frequency. These results demonstrated that it is possible for rats to understand an encoding-based BCI system and control a 1D machine using PFC activity to obtain reward.

关键词： brain-computer interface prefrontal cortex rat one-dimensional single neuron recording

DEM simulation of particle mixing in a sheared granular flow

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Particuology 2008年第6期6卷 445-454页

作者： Li-shin Lu Shu-San Hsiau Department of Mechanical Engineering Technology and Science Institute of Northern Taiwan Department of Mechanical Engineering National Central University

Mixing behaviors of particles are simulated in a sheared granular flow using differently colored but otherwise identical glass spheres, with five different bottom wall velocities. By DEM simulation, the solid fractions, velocities, velocity fluctuations and granular temperatures are measured. The mixing layer thicknesses are compared with the calculations from a simple diffusion equation using the data of apparent self-diffusion coefficients obtained from the current simulation measurements. The calculations and simulation results showed good agreements, demonstrating that the mixing process of granular materials occurred through the diffusion mechanism.

关键词： DEM Particle mixing Sheared granular flow Diffusion