• Korean journal of applied entomology
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• v.50 no.1
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• pp.39-46
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• 2011

This study analyzed effects of different sound treatments in frequencies and intensities on digestion and immune physiological processes of the beet armyworm, Spodoptera exigua larvae. Without effect on egg hatch, sound treatments with 100-5,000 Hz at 95 dB suppressed feeding behavior and inhibited a digestive enzyme activity. In addition, two dimensional electrophoresis of midgut luminal proteins indicated a marked difference of the sound-treated larvae. In response to 5,000 Hz at 95 dB, larvae showed a significant decrease in hemocyte nodule formation against fungal challenge along with significant suppression in phospholipase $A_2$ activity in hemocyte and plasma. With increase of sound frequencies, the treated larvae showed an enhanced susceptibility to insecticides. Such sound frequency effect was significantly modulated with different sound intensities. These results suggest that sound treatment may give adverse stress to physiological processes of S. exigua larvae and may be applied to a nonchemical insect pest control.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.423-430
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• 2013

Recently, the personal identification technologies using vein pattern of back of the hand, palm, and finger have been developed actively because it has the advantage that the vein blood vessel in the body is impossible to damage, make a replication and forge. However, it is difficult to extract clearly the vein region from captured vein images through common image prcessing based region segmentation method, because of the light scattering and non-uniform internal tissue by skin layer and inside layer skeleton, etc. Especially, it takes a long time for processing time and makes a discontinuity of blood vessel just in a image because it has non-uniform illumination due to use a locally different adaptive threshold for the binarization of acquired finger-vein image. To solve this problem, we propose illumination normalization based fast method for extracting the finger-vein region. The proposed method has advantages compared to the previous methods as follows. Firstly, for remove a non-uniform illumination of the captured vein image, we obtain a illumination component of the captured vein image by using a low-pass filter. Secondly, by extracting the finger-vein path using one time binarization of a single threshold selection, we were able to reduce the processing time. Through experimental results, we confirmed that the accuracy of extracting the finger-vein region was increased and the processing time was shortened than prior methods.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.6
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• pp.529-535
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• 1984

This study aims at obtaining the basic data for the development of pen shell culture at Yoja Bay, the southwest coast of Korea. The authors dealt with the annual gonadal changes of the pen shell, Atrina pectinata japonica, to find out the gametogenesis, reproductive cycle and spawning season, and to investigate the fluctuation in the larval occurence in Yoja Bay. From July 1983 to June 1984, an average of 20 individuals as specimens were monthly collected by commercial fishing dredge near Manwol island located at the mouth of Yoja Bay. The degree of gonadal development was determined by the histological observations as resting spent stage, early developmental stage, after developmental stage, early spawning stage, after spawning stage and degenerative stage. According to these degrees of gonadal development, annual reproductive cycle of the pen shell population was determined. From July to August, the gonads were changed through degenerative into resting stage and, in September and October, they became entirely empty gonads. From November they showed the first sign of gametogenesis developing very slowly. Nevertheless, the developing gametes did not increase in number probably owing to a phagocytic phenomenon by phagocytes which appeared in the gonad during this stage. Some individuals started spawning in April and in May majarity of individuals were in spawning stage. In June, majority of the individuals showed signs of degenerative stage. Therefore, the authors came to a conclusion that the pen shells in Yoja Bay spawn chiefly in May. And this is also supported by the result of the survey on the planktonic occurrences of the pen shell larvae. Namely, there were no larvae at all in April, only a few in May and many in June by vertical water sampling.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.282-290
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• 2011

Two species of demersal fish, Liparis tessellates (cubed snailfish) and Hemitripterus villosus (shaggy sea raven), were investigated in relation to seasonal chemical composition. Total fat contents of the two fish were very low and were not appreciably different throughout the year, whereas their fatty acid compositions were significantly different depending on season. Noticeable changes in the moisture and protein contents in the two fishes were observed before and after spawning. Cubed snailfish showed relatively high amounts of total amino acids and free amino acids during summer months, whereas the levels of those in shaggy sea raven remained relatively unchanged throughout the year. Regardless of season, the major fatty acid of the two fishes was palmitic acid and most of polyunsaturated fatty acids (PUFAs) were n-3 PUFAs. Lead was over the legislative limit in some samples of the two fishes.

• Korean Journal of Optics and Photonics
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• v.16 no.4
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• pp.384-391
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• 2005

A polymer optical microring resonator, which is laterally coupled to a straight bus waveguide, has been proposed and demonstrated using a nanoimprint technique. The propagation loss of the ring waveguide and the optical power coupling between the ring and bus waveguides was calculated by using a beam propagation method, then the dependence of the device performance on them was investigated using a transfer matrix method. We have especially introduced an imprint stamp incorporating a smoothing buffer layer made of a silicon nitride thin film. This layer played an efficient role in improving the sidewall roughness of the waveguide pattern engraved on the stamp and thus reducing the scattering loss. As a result the overall Q factor of the resonator was greatly increased. Also it reduced the gap between the ring and bus waveguides effectively to enhance the coupling between them, without relying on the direct writing method based on an e-beam writer. As for the achieved device performance at the wavelength of 1550 nm, the quality factor, the extinction ratio, and the free spectral range were ~103800, ~11 dB, and 1.16 m, respectively.

• Korean Journal of Optics and Photonics
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• v.31 no.6
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• pp.281-289
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• 2020

This paper reports a slim mobile lens design using a hybrid refractive/diffractive optical element. Conventionally a wide field of view (FOV) camera-lens design adopts a retrofocus type having a negative (-) lens at the forefront, so that it improves in imaging performance over the wide FOV, but with the sacrifice of longer total track length (TTL). However, we chose a telephoto type as a baseline design layout having a positive (+) lens at the forefront, to achieving slimness, based on the specification analysis of 23 reported optical designs. Following preliminary optimization of a baseline design and aberration analysis based on Zernike-polynomial decomposition, we applied a hybrid refractive/diffractive element to effectively reduce the residual chromatic spherical aberration. The optimized optical design consists of 6 optical elements, including one hybrid element. It results in a very slim telephoto ratio of 1.7, having an f-number of 2.0, FOV of 90°, effective focal length of 2.23 mm, and TTL of 3.7 mm. Compared to a comparable conventional lens design with no hybrid elements, the hybrid design improved the value of the modulation transfer function (MTF) at a spatial frequency of 180 cycles/mm from 63% to 71-73% at zero field (0 F), and about 2-3% at 0.5, 0.7, and 0.9 fields. It was also found that a design with a hybrid lens with only two diffraction zones at the stop achieved the same performance improvement.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.1
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• pp.77-86
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• 1980

Asking to change the cropping patterns to save the labor and capitals in paddy rice cultivation, the study was intended to know the weed problems under the various possible cultural systems; namely, direct seeding (in broadcast and row), machine transplanting and hand transplanting. Under the conditions as weedy check plots, paddy yields were significantly variated among cropping systems, and the functions of panicle No. and spikelet No. to the yield were neglected, among others. However, the yield and yield components were narrowed among cropping systems, and the function of spikelets number per area was comparatively improved to the others.