• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.72-76
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• 2000

The study was conducted to investigate the developmental periods and effect of several insecticides on Hemiptarsenus sp., ectoparasitoid of Liriomyza trifolii. The mean length and width of egg were 0.5mm and 0.1mm. The mean length of larva, pupae, abult female, and abult male were 1.9mm, 2.0mm, 2.2mm, and 1.8mm, respectively. Developmental periods of Hemiptarsenus sp. from egg to larva at 15, 20, 25, $30^{\circ}C$ were 16.9, 8.8, 5.9, and 4.5 days, and those of pupa were 20.7, 9.7, 5.6, and 3.4 days, respectively. Based on these results, developmental threshold temperatures and effective temperatures were $9.5^{\circ}C$, 91.5 degree-days in egg-larval stage, $10.9^{\circ}C$, 142.3 degree-days in pupal stage. When several insecticides were evaluated to Hemiptarsenus sp. at the recommended concentrations, B.t WP, diflubenzuron WP, and cyromazin were negligiblly effective all life stages. Fipronil SC, cartap SP, spinosad GW were less toxic to larva and pupa, but highly toxic to adults. Abamectin EC was less toxic to all life stages, but inhibited oviposition of 50% more to Hemiptarsenus sp. female.

• Korean Journal of Ichthyology
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• v.19 no.1
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• pp.57-65
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• 2007

A new species of the rajid genus Okamejei is described from a single specimen (295 mm TL) from off Shantou, Gwangdong in the South China Sea. The new species differs from all other congeners in the following combination of characters: snout pointed, dorsal head length 6.7 times interorbital width, tail moderately wide and long, its length 48.5% TL, interdorsal distance less than length of first dorsal fin base, postdorsal tail short as 5.8% TL, small evenly distributed dark brownish spots, without ocelli on dorsal surface of disc, pores of ampullae of Lorenzini on ventral surface distributed from snout tip to distal end of metapterygium, scapulocoracoid high, its height about 1.4 times rear corner height, trunk vertebrae 23, predorsal tail vertebrae 50 and pectoral fin radials 96.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.672-681
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• 2019

The ecological characteristics of Sargassum macrocarpum, an ecologically and commercially valuable brown alga, were investigated from May 2018 to June 2019 in Jeju Island, Korea. The S. macrocarpum population formed patches at depths of 3-5 m. Growth in the length of the alga reached a maximum of 135.3±20.0 cm in June. The weight of the alga reached a maximum of 3.6±2.1 kg·wet-wt in May. The mean density and biomass of S. macrocarpum was 4.5 individuals·m^-2 and 4.6 kg·wet-wt.·m^-2 in their habitat. Receptacles were observed from April to August and egg release was detected from June to July when the seawater temperatures were 19.3-22.9℃. The developmental initiation of thalli occurred at temperatures above 14.1℃ and maturation required approximately 726.3 degree-days. The reproductive allocation of this alga, calculated from the reproductive frond length(RFL) and reproductive frond weight(RFW) indices to the whole length and weight, reached a maximum of 69.3% in June. The growth and maturation patterns of S. macrocarpum could be divided into vegetative growth (October-January), maturity preparation (February-April), maturation (May-June), egg release (June-July), and resting period (August-September). This was the first study to examine an S. macrocarpum population throughout the entire year in a natural habitat in Jeju Island, Korea.

• Applied Microscopy
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• v.38 no.2
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• pp.81-87
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• 2008

Alkaline reduced water (ARW) has been used for drinking widely in several countries of Asia. The safety and clinical effects of ARW has been reported including anti-oxidative effect and intestinal abnormal fermentation. To confirm the effect of ARW on DSS-induced acute inflammatory bowel disease (IBD) mouse model, we observed the length of total large intestine and the histopathological changes after supplying mineral induced-ARW (MARW) for 2 weeks and oral administration of 4% DSS (dextran sulfate sodium). As the result, the length of total large intestine and the disease scores by macro and microscopical access in the ARWsupplied group showed no significant differences compared with those in the control group. This result suggests that the supply of ARW for 2 weeks exerted no effect on amelioration in the DSS-induced acute IBD model. However, in consideration of the effect of ARW on the improvement of intestinal environment and gastrointestinal disease, this result seems that acute IBD animal model is not suitable or the period of ARW supply is not enough to prove the effect of ARW. The ameliorative effect of ARW on the intestinal abnormal fermentation has been confirmed by some researchers, but the precise mechanism also remain unclear. In conclusion, although MARW had no effect on the DSS-induced acute experimental colitis model, further studies on the verification of the effects of ARW by using other intestinal disease model and by long-term supply of ARW will be required. Also, It needs to clear the mechanism of ARW on the intestinal environment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.1
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• pp.11-16
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• 1984

The backscattering cross sections of live fish and the probability density function of fish echoes were measured at side aspect. The measurements were made at 40 and 170 in KHz. The specimen fishes on the experiments were two catfish-total length of 16.8cm(L/λ is about 4.5, where the L is length, the λ is the sound wavelength) and 23cm(L/λ, ~6.1), a carp(Cyprinus carpio) of 17.5cm(L/λ, ~4.7), a Telapia(Tilapia mossambica)of 19.5cm(L/λ, ~5.2) and several fishes. Those lengths ranged from 10.7 to 24.0cm. The results of the measured maximum backscattering cross sections were 5.62$\times$10 super(-5) to 7.23$\times$10 super(-4) m super(2). Huang and clay reported that, when the fish was moving gently, the probaiblity density function of the fish echces was approximately the same with the Rayleigh probability density function. Thereafter Ehrenberg et al. also reported that the Rayleigh probability density function on fish was performed at the critical acoustic length ratio or more in theoretical base. Recently Dahl and Mathisen tested the Rayleigh probability density function on fish when the fish-length-to-wavelength ratios were greater than 100. In this paper the experimental result was also not accorded with the Rayleigh probability density function when the fish-length-to-wavelength rations were lower than the critical ratio.

• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.293-302
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• 2010

Taxa of Artemisia collected in Korea were constructed by molecular phylogenetic analysis based on the internal transcribed spacer(ITS) regions of nrDNA. The length of the ITS sequences aligned using the clustal X program was 636~643 bp, and the lengths of the ITS1 and ITS2 regions were 251~255 bp and 217~222 bp, respectively. The total number of variable sites was 95 for the entire sequence, and a parsimony- informative site represented an efficacious site in ITS1 rather than in ITS2. The maximum parsimony tree as calculated by the MEGA 4 program was clustered into five clades. The taxa(A. capillaris, A. japonica var. japonica, A. japonica var. hallaisanensis, A. japonica subsp. littoricora) degenerated ovary of clade 1 was supported as the subgenus Dracunculus by Ling's classification system. The results show that A. nakaii and A. fukudo were quite similar genetically(Boostrap 99%) and that the scientific name of Korean A. dubia should be reconsidered. A. sp. distributed in Ganghwa province was grouped with A. argyi(Boostrap 89%). These results suggest that the molecular techniques used in this study could be useful for the phylogenetic analysis of Korean Artemisia herbs having variations in their morphological characteristics.

• Korean Journal of Plant Resources
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• v.26 no.5
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• pp.613-618
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• 2013

This study was conducted to investigate the morphological characteristics of leaf and the genetic diversity of Berchemia racemosa var. magna which is only found in Anmyeon Island of South Korea. ANOVA test showed that there were significant differences among individuals within population in all 10 leaf characteristics. Average characteristics of 39 individuals were 11.8 cm in leaf length, 7.1 cm in leaf width, 1.67 in leaf index, 5.4 cm in upper 1/3 width, 6.2 cm in lower 1/3 width, 3.6 cm in petiole length, 0.19 mm in leaf thickness, 11.5 ea. in number of veins (left), 11.4 ea. in number of veins (right) and 61.7 $cm^2$ in leaf area, respectively. Except for leaf thickness (18.8%), petiole length (21.7%) and leaf area (22.0%), the coefficients of variation of most leaf characteristics were relatively low (<15.0%). A total of 50 bands was generated from 8 selected I-SSR primers. The estimates of genetic variation were 1.719 in effective number of alleles ($A_e$), 26.0% in proportion of polymorphic bands (P), 0.410 in expected heterozygosity ($H_e$) and 0.598 in Shannon's diversity index (S.I.), respectively. In spite of the small number and the limited distribution, the B. racemosa var. magna population in Anmyeon Island showed high genetic diversity.

• Korean Journal of Optics and Photonics
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• v.16 no.3
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• pp.248-253
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• 2005

We designed and fabricated a compact multi-mode interference (MMI) wavelength demultiplexer using the concept of 'Improved Quasi-State' modes. The output power and extinction ratio were improved by utilizing modal phase error which is specially occurred in low-index contrast. For a designed demultiplexer, the mode propagation analysis with effective index approximation shows significant improvement of extinction ratio to -25 dB for both $1.31{\mu}m\;and\;1.51{\mu}m$ wavelength region and the split-length was reduced about 1/5 of other MMI devices. The fabricated device shows successful characteristics for both 1.31 and $1.55{\mu}m$ wavelengths. These results demonstrate the potential of low-index materials system and the embossing process for photonic integrated circuits.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.167-175
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• 2015

Purpose: The new-type rangefinder, which is using the biprism principle, is introduced to develop the range finder which can be easily carried by soldiers, and in order to realize those technologies specifically, we try to develop a scope for military rangefinder by doing optical design which can secure enough space to move the biprism. Methods: After setting up the verious initial condition to realize two kinds of goals, that are the securement of enough space to move the biprism and the easy-exchangeability of two kinds of biprisms, and then the optical system was optimized by using optical design program CodeV in order to minimize the finite ray aberrations. Results: We designed the biprism housing to makes it possible to swap the two kinds of biprisms. It was appeared that the Schmidt prism is suitable as erecting prism which can make sure the space to move the biprism. 16.5 mm was good for the face length of Schmidt prism. The optical system with a Schmidt prism and a biprism was designed, and the finite ray aberrations was minimized. Conclusions: We developed a 5X scope for an optical rangefinder using a biprism and a Schmidt prism with 16.5 mm face length. This scope is valid for the optical system which has the effective field angle of ${\pm}3.6^{\circ}$, and the finite ray aberrations are well controlled within the ${\pm}8.95^{\prime}$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.4
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• pp.315-322
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• 1990

In order to find out the most favorable shape and structure of pot for conger eel, Astroconger myriaster(Brevoort), the box type, tube type and flat box type of net pots and the pipe type of plastic pot were prepared. Then, the ability of the pots attracting the eel into them were investigated through a tank experiment. The attracting ability was highest in the pipe type without distinction of its length, 50cm and 60cm. In the flat box type, the effective height of pot and the diameter of entrance tip turned out 5cm respectively. But the ability was very poor in the rest pots, especially in the tube type. Thus, the pipe type and flat box type of pots were employed again in a field experiment for comparing their catches with those of the conventional bamboo and plastic pots. In the experiment, the catches were the most in the pipe type and second in the flat box type. But the bamboo and plastic pots both produced comparatively low catches, showing no significant difference between them. It was therefore concluded that the pipe type of pot might be the most favorable one for catching the conger eel.