• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.4
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• pp.433-441
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• 1998

• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.129-137
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• 1999

A parametric curve interpolator has been proposed for machining curves instead of a linear interpolator in which curves are approximated by a set of line segment. The parametric curve interpolator is superior to linear interpolator in machining time and contour error and generate exact position commands directly from curve equations. In this paper, a new toolpath generation method is proposed based on the parametric curve interpolator. This method retains all the benefits of parametric curve interpolator and can bound the scallop height within a specified value. By interpolating curves and surfaces directly from the mathematical equations, the amount of data from CAD/CAM system to CNC controller can be significantly reduced. The proposed method was implemented on a CNC controller and was confirmed to give a better result than the other existing method.

• Proceedings of the KWS Conference
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• 1997.05a
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• pp.84-86
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• 1997

• Progress in Medical Physics
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• v.5 no.2
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• pp.49-55
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• 1994

Multileaf Collimator is an essential tool for conformal therapy. We have measured the scallop penumbars of a poligon-shape field produced by Multileaf Collimator(MLC) with various leaf widths and the penumbra from conventional block, and compared the difference between them for the energy of photons, leaf widths, and angle of filed edges in order to find out the optimum leaf width. In addition, we have simulated a treatment of 20 factionations with errors of patient positioning. Optimum cost-benefit balanced leaf width is 8 mm.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.397-403
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• 2021

Polycyclic Aromatic Hydrocarbons (PAHs) were analyzed and safety evaluation was carried out in Korean coastal area. The target congeners were benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene, and chrysene. The method of analysis was significant. The highest PAHs 4 congener concentrations (12.2 ㎍/kg) was found in the mussel of Gangwon area. Comparison among the average concentration of PAHs for each congener showed that, benzo[a] anthracene was found in mussel (0.276 ㎍/kg), oyster (0.463 ㎍/kg), ark shell clam (1.92 ㎍/kg), and chrysene was found in mussel (0.848 ㎍/kg), oyster (1.36 ㎍/kg), scallop (0.489 ㎍/kg), sea squirt (3.07 ㎍/kg), and ark shell clam (0.449 ㎍/kg). In addition, benzo[b]fluoranthene was found in mussel (0.253 ㎍/kg), scallop (0.244 ㎍/kg), and sea squirt (1.64 ㎍/kg). The most hazardous benzo[a]pyrene was found in mussel (0.147 ㎍/kg), and scallop (0.244 ㎍/kg), it was not detected in the other shellfishes. However, all the PAHs levels recorded in this study did not exceed international MRLs. There was no significant difference among the PAHs concentration in shellfish based on sampling area or species. Body exposure was calculated based on PAHs concentration and intake rate. The results of this study indicated that PAHs in shellfish were within acceptable safe levels.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.1
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• pp.35-48
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• 1995

To develop the optimal design method for the longline type scallop culturing facilities in the open sea numerical calculations and hydraulic model experiments are carried out for the stability and function optimization. Using the results for the motion and tension of the facilities, stable design concepts and effects of motion control system by vertical anchor and resistance discs art discussed. The results of this study that can be applied to the design are as follows: 1) Total external forces by design wave $(H_{1/3}\;=\;6,7\;m,\;T_{1/3}\;=\;12sec)$ at the coastal waters of Jumunjin for unit facility (one main line) are estimated to 5-20 tons, and required anchor weights are 10-40 tons in the case of 2-point mooring system. Though the present facilities are stable to steady currents, but is unstable to the extreme wave condition of return period of 10 years. 2) The dimensions and depth of array systems must be designed considering the ecological environments as well as the physical characteristics including the mooring and holding forces that are proportional to the length and relative depth of main line to wave length, and the number of buoys and nets. 3) Oscillation of the facility is influenced by water particle motion and the weight of hanging net, and is excited at both edge, especially at the lee side. To reduce the motion of the nets, the vertical anchoring system and the resistence disc method are recommended by the experimental results, 4) The damage of rope near the anchor by abrasion should be prevented using the ring-type connection parts or anchor chains.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.201-206
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• 2002

Reproductive cycle of the bay scallop, Argopecten irradians, transplanted from China on 16 August 1996, was investigated monthly until August 1997 in the Deukyang Bay, Jangheung-gun, Jeollanam-do, Korea. Sexuality of this species is hermaphrodite and oviparous, Monthly changes in the soft part weight index and adductor muscle weight (g) began to increase from October and reached the maximum in November, and then the values gradually decreased from December to August, The gonadosomatic index (GI) began to increase in March and reached the maximum in April. Thereafter, the values gradually decreased from May to December, The reproductive cycle of this species, transplanted in the south coast of Korea could be divided into 5 successive stages; early active (October to February), late active (November to May), ripe (February to May), spawning (May to June) with a peak in May, and spent/inactive stage (June to August).

• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.844-849
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• 2005

Bacteriocidal effect of calcium oxide (CaO, scallop shell powder) on reduction of microorganism in sesame leaf was evaluated through comparison with chemical sanitizers such as chlorine, ethanol, and hydrogen peroxide. CaO showed 0.55-1.49, 0.85-2.56, 0.16-1.08, 0.30-1.14, and $0.19-1.07\;log_{10}$ CFU/g reductions of total aerobic bacteria, total coliforms, Escherichia coli, Listeria monocytogenes, and Salmonella typhimurium respectively, indicating possible use of CaO as effective natural sanitizer.

• Journal of Aquaculture
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• v.18 no.1
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• pp.1-6
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• 2005

This study focused on spawning season, induce spawning, spawning and larval development of the Jicon scallop in Daehuksan Island of southwestern waters in Korea. The condition index and gonadosomatic index were used to investigate the reproductive pattern of the Jicon scallop. The major spawning season was from July to August, showing an unimodal gametogenic cycle per year. Several different tests were carried out to induce spawning of the mature male and female C. farreri. For females, the injection of serotonin, temperature induction technique and the combination of the both treatments produced significantly faster gamete release. Unlike females, males spawned only in response to the UV rays irradiation stimulation. Mean size of fertilized eggs was 69.5 $\mu$m in diameter. After fertilization, the zygote could be divided into 2 cells as early as 2 hours. It took about 8 hours to develop the 8-cell stage, about 20 hours to hatch trochophore larvae, and about 40 hours to be D-shaped larvae.

• Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.276-285
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• 2009

Despite great commercial interest, relatively little has been described about molecular mechanism of bivalve reproduction. We investigated genes involved in ovarian maturation of the Yesso scallop, Patinopecten yessoensis. GSI index and histological analysis revealed that maturation of ovary begin in February and spawning period is from April to June which is similar to the previous study in the East Sea. As result of combination analysis of differential display RTPCR (DDRT-PCR) and histological examination, vitellogenin (Vg), ferritin (Ft) and ADT/ATP carrier protein (ACC) were identified as differently expressed genes in maturating ovary. Endpoint RT-PCR results showed that Vg is ovary-specific genes whereas Ft and ACC are expressed ubiquitously suggesting that Vg can be good molecular markers for ovarian development and sex determination in bivalves. Quantitative PCR results revealed that Vg were expressed highest during growth stage and appears to play a major role in oocyte maturation. On the contrary, expression of Ft was highest after spawning stage, which suggests that up-regulation may be involved in spawning and inactive stages in which the scallops recover from spawning. In addition, high level of the mitochondrial gene, ACC, may play a role in energy metabolism in maturating oocytes. Isolation and molecular studies of these key genes will expand our knowledge of the physiological changes from various exogenous factors including temperature, salinity, pH, even or numerous endocrine disrupting chemicals (EDCs) during reproductive cycle. In addition, further study of these genes implicates various industrial applications including the stable seed production, increased food quality, or economic aquaculture system.