Molecular dynamics computer experiments have been carried out for two-dimensional hexagonal mass-spring model crystals. Anharmonic forces up to the third order were taken into account, and central forces were considered between the nearest neighbor atoms. Input pulse displacements were given to atoms on the crystal surface, and induced displacements and velocities of all atoms in the crystal were computed. Solitons were produced as the atomic excitation, and the propagation velocity and the strength of solitons were enumerated. The dependences of these two quantities on the pulse application direction and on two parameters, the magnitudes of the input pulse and the higher order force constant, were investigated. Two crystallographic directions were taken for the input pulse direction, and values of the two parameters were widely varied. On the basis of the results of the simulation, a possible laboratory experiment of soliton production was considered.
A molecular dynamics computer simulation has been carried out for a monatomic, anharmonic, and two-dimensional hexagonal model crystal. Central forces between the nearest neighbor atoms and anharmonic forces up to the third order are considered. Pulse input displacements are applied to the line of atoms at one end of a rectangular crystal, and the atomic excitations propagating in the crystal are observed. The excitations are shown to be phonons or solitons when the applied pulse is small or large, respectively. A mass defect – an atom of which the mass is lighter or heavier than that of the lattice atoms – is placed near the center of the crystal. The excitation is scattered by the defect, and the simulations are made for various cases of large and small inputs, and light and heavy mass defects. The obtained results are represented using two-dimensional maps. The intention of the study and the significance of the results are briefly discussed.
In CDMA systems using block spreading techniques, where a data-block modulates a spreading sequence to produce a transmitting symbol, a user inherent orthogonal carrier-frequency modulating system is proposed. This method contributes to accommodating as many users as the processing gain L and to reducing the guard sequence overhead. Applying a MIMO configuration without using coding and multiple constellation on PSK modulation to this system, especially using N pieces of receive antennas is considered. This block spreading system is capable of accommodating as many users per orthogonal carrier as N, by using a method of concatenating the N symbols received at N antennas. This means that the aggregate data rate per chip increases N in the maximum. Further it is shown that a fairly good error rate performance is achieved by selecting the practical aggregate data rate to be about 80% of the maximum rate.
We are developing a technique to monitor information during the training for non-attendant student. We found the forward-bent of patient can be a parameter indicating the mental condition of client. The training was recorded by a digital video-camera. After the training, the forward-bent was measured manually from recorded pictures. In this paper, we reports the application of pattern matching technique to measure the forward-bent. As result of preliminary experiment, it was found that the downward distance calculated by the matching technique and the distance obtained manually are mutually related. In addition, frequency analysis is enabled by this technique. We examined possibility to grasp strain state of mind by frequency analysis, for example, stiff movement by strain of mind, and to be relaxed by change of frequency distribution. We developed a DV camera system in this analysis, but Video capture from a DV camera and conversion work to huge number of still image is necessary. We plan the camera interface connection such as IEE1394or USB2.0 protocol to a PC directly and an image transfer to memory improves efficiency.
This study focused on determining the past changes and predicting the future trends in eutrophication of the Bolgoda North lake, Sri Lanka using in situ Chlorophyll-a (Chl-a) measurements and Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) satellite data. This Lake is located in a mixed land use area with industries, some agricultural lands, middle income and high income housing, tourist hotels and low income housing. From March to October 2013, water samples from five sampling sites were collected once a month parallel to ASTER overpass and Chl-a, nitrate and phosphate contents of each sample were measured using standard laboratory methods. Cloud-free ASTER scenes over the lake during the 2000-2013 periods were acquired for Chl-a estimation and trend analysis. All ASTER images were atmospherically corrected using FLAASH software and in-situ Chl-a data were regressed with atmospherically corrected three ASTER VNIR band ratios of the same date. The regression equation of the band ratio and Chl-a content with the highest correlation, which was the green/red band ratio was used to develop algorithm for generation of 15-m resolution Chl-a distribution maps. According to the ASTER based Chl-a distribution maps it was evident that eutrophication of this lake has gradually increased from 2008-2011. Results also indicated that there had been significantly high eutrophic conditions throughout the year 2013 in several regions, especially in water stagnant areas and adjacent to freshwater outlets. Field observations showed that this lake is receiving various discharges from factories. Unplanned urbanization and inadequacy of proper facilities in the nearby industries for waste management have resulted in the eutrophication of the water body. If the present trends of waste disposal and unplanned urbanization continue, enormous environmental problems would be resulted in future. Results of the present study showed that information from satellite remote sensing can play a useful role in the development of time series Chl-a distribution maps. Such information is important for the future predictions, development and management of this area as well as in the conservation of this water body.
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