• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.4
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• pp.334-343
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• 2019

We investigated the sanitary characteristics of Alaska pollock Theragra chalcogramma roe as a raw material based on the standards of several countries. The standards for raw materials of Alaska pollock roe for lead, total mercury, $^{134}Cs+^{137}Cs$, and $^{131}I$ were those of the South Korean Ministry of Food and Drug Safety; Staphylococcus aureus, Salmonella spp., Clostridium botulinum, methyl mercury, $^{134}Cs+^{137}Cs$, $^{131}I$, $^{239}Pu$, and $^{90}Sr$ were those of the United States Food and Drug Administration; lead, methyl mercury, inorganic arsenic, chrome, $^{134}Cs+^{137}Cs$, and $^{131}I$ were those of the Ministry of Agriculture of China; nitrite ion, $^{134}Cs+^{137}Cs$, $^{239}Pu$, and $^{235}U$ were those of the Ministry of Health, Labor and Welfare of Japan; $^{134}Cs+^{137}Cs$, $^{131}I$, $^{239}Pu$, and $^{90}Sr$ were those of Codex; and $^{134}Cs+^{137}Cs$, $^{131}I$, $^{239}Pu$, $^{241}Am$, and $^{90}Sr$ were those of the European Food Safety Authority. The results for the global standard items other than C. botulinum (lead, total mercury, methyl mercury, inorganic arsenic, chrome, $^{134}Cs+^{137}Cs$, and $^{131}I$, S. aureus, and Salmonella spp.) suggest that Alaska pollock roe is safe for use as a raw material.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1177-1192
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• 2018

The objective of this study is to develop the existing drainage system for catching the partial leakage of tunnel structures operating in cold region. The drainage system consists of drainage board, Hotty-gel as a waterproofing material, cover for preventing protrusion of Hotty-gel, air nailer, fixed nail, pipe for collecting ground leak, pipe for conveying ground leak, wire-mesh, and sprayed cement mortar. The drainage systems were installed in conventional concrete lining tunnels to evaluate the site applicability and constructability. The performances of waterproof and the drainage in the drainage system were evaluated by injecting 1,000 ml of red water in the back of the drainage system at 7 days, 14 days, 21 days, 28 days, 2 months, 3 months, 4 months, 5 months, 6 months, 7 months and 8 months. During 8 months of field test, the average daily temperature of the tunnel site was measured from $-16.0^{\circ}C$ to $25.6^{\circ}C$. The daily minimum temperature was $-21.3^{\circ}C$ and the daily maximum temperature was $30.8^{\circ}C$. There was no problem in waterproof and drainage performance of the drainage board in the drainage system. However, the pipe for conveying ground leak had the leakage problem from 14 days. It is considered that the leakage of the pipe for conveying ground leak was caused by the deformation of the pipe of the flexible plastic material having a thickness of 0.2 cm by using the high pressure air nailer and the fixing pin and the insufficient thickness and width of the hotty-gel for preventing the leakage.

• Journal of Mushroom
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• v.17 no.1
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• pp.1-6
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• 2019

Agrocybe cylindracea was cultured in a bag, in which sawdust culture medium (1 kg) is put in a plastic bag (PE), with poplar sawdust, rice bran, wheat bran, and dried bean curd refuse in the ratio of 70:10:10:10 (v/v). 2% of the culture medium was inoculated with the liquid starter of Agrocybe cylindracea, and this was incubated at $25^{\circ}C$. After incubation, the A. cylindracea was further cultured by cutting the top vinyl portion of the bag down to the level of the culture medium surface of the first inoculation part. The cut culture medium was placed in a growth room at $25^{\circ}C$, and pin-heading was induced under light irradiation at 99% humidity and 1,000 ppm $CO_$ level for 3days. When the grow the environment was controlled at 95% humidity and $21^{\circ}C$, the bending of the stem was less as compared to that when the cap of the bag had been removed. The number of effective fruiting bodies per bag increased by 140% (28.8), the quantity per bag increased by 29.5%, and 148.5 g A. cylindracea could be potentially harvested.

• Research in Plant Disease
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• v.25 no.3
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• pp.124-130
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• 2019

The study was conducted to investigate the infestation and distribution of plant-parasitic nematodes on Chinese yam (Dioscorea batatas) in Andong, Korea. Root-knot nematodes, Meloidogyne incognita was the most prevalent nematode species which is found from 43 yam fields (81.1%) with high population densities (average of 450 juveniles/$300cm^3$). Other nematodes, root-lesion nematode (Pratylenchus spp.) and pin nematode (Paratylenchus spp.) were less problematic. Density of juveniles (J2) of M. incognita was $10\;J2/300cm^3$ by August, then increased to 274 in September and 624 in October. The highest J2 density was found at the soil depth between 40 and 50 cm ($1,840\;J2/300cm^3$). M. incognita was able to infest yam tuber down to a depth of 70 cm and developed galls outside and brown spots inside. The highest number of females were found at 40-50 cm (79 females/10 cm piece) tuber from the top.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.382-388
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• 2019

Increased anterior teeth mastication following posterior teeth loss leads to greater anterior occlusal force. It may cause greater attrition of anterior teeth, traumatic force occlusion (TFO), also often followed by antagonist extrusion and occlusal disharmony. This clinical report describes the treatment for a 67-year-old female patient diagnosed with loss of both maxillary and left mandibular posterior teeth, severe attrition of maxillary and mandibular anterior teeth and extrusion of multiple teeth. A diagnostic cast was mounted on articular in centric relation (CR) position to evaluate vertical dimension (VD) and interspace. To provide adequate space for the prosthetic reconstructions, VD was increased by 3 mm on the anterior pin. And then diagnostic wax-up was completed upon that VD. Wax-up was converted to provisional restorations and verified in the patient's mouth and the final restorations were delivered. Clinical follow up examination held 3 months after temporary restoration owing to changes in vertical dimension revealed proper function in mastication without evidence of temporo-mandibular joint (TMJ) disorders. This clinical report presents successfully restoring severe attrition case with increasing vertical dimension resulting in satisfaction in esthetics and function.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.558-564
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• 2021

The water purifier market has increased rapidly in recent years. The welding technology of the evaporator is a key component that determines the level of ice production and the cold water performance of an ice purifier. The finger type evaporator of an ice purifier can remove ice and is divided largely into an instant heat method and a hot gas method. In the hot gas type evaporator, particularly during the production process, the pinhole phenomenon inside the copper pipe and clogging problems occur intermittently when welding high-pressure pipes due to the high-temperature oxygen welding. Its use in a water purifier can cause a problem in that ice and cold water do not form, and repairs cannot be made on site. To solve this problem, in this study, a cap jig was applied to improve the welding defect of the hot gas evaporator. In addition, the oxygen welding flame size was adjusted so that the heat source could be well supplied to the cap jig, and the effectiveness was confirmed through a wave pressure test, a test, and a thermal shock test.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.715-721
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• 2011

This study was conducted to estimate aboveground biomass and nitrogen storage potential of tree species-eight clones of a poplar and hybrids, one clone of Salix alba L., dawn redwood (Metasequoia glyptostroboides Hu and W.C. Cheng), yellow poplar (Liriodendron tulipifera L.), Okamoto maple (Acer okamotoanum Nakai), and pin oak (Quercus palustris $M{\ddot{u}}nchh.$)- after treating with liquid pig manure. Stems showed the highest percentage of aboveground biomass, and followed by branches and leaves. Nitrogen content in aboveground biomass components was the highest in leaves, and followed by branches and stems. Average aboveground biomass production was higher in the clones and species treated with manure than those of not treated, 30 ton/ha and 16 ton/ha, respectively. In the manure-treated site, clone 'Dorskamp' of Populus deltoides${\times}$Populus nigra showed the highest aboveground biomass (48.3 ton/ha). Average nitrogen storage potential was superior in the clones and species treated with manure than those of not treated, 159 kg/ha and 90 kg/ha, respectively. Clone 'Dorskamp' also showed the greatest nitrogen storage potential (286.5 kg/ha) among tested tree species. Therefore, 'Dorskamp' is the most suitable clone for treating liquid pig manure, but additional studies are needed to determine any damages or tolerance from the treatment.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.6
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• pp.48-57
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• 2020

This study was aimed to determine the history of Son keechung laurel tree, which is designated and managed as Seoul Metropolitan Government Monument No. 5. Sohn keechung's victory in the marathon at the 1936 Berlin Olympics served as an opportunity to encourage great pride and national spirit for the Korean people's national spirit who had spent their painful days under Japanese colonial rule. The seedlings that Son keechung received at the time are currently growing at Son Keechung Sports Park on the hill in Manri-dong, west of Seoul Station, and are Quercus palustris. That variety of Tree is native to the United States. The 11th Berlin Olympics, held in 1936, is a golden opportunity for Hitler to show off the history and cultural excellence of the German race, so it does not make sense to award victors an American giant oak instead of the German oak tree. The Seoul Metropolitan Government and various media outlets made a fait accompli due to Hitler's simple mistake. However, this study revealed that the laurel that Son received was the Quercus robur, based on the articles of the Korean newspaper, the German daily newspaper, and the recently introduced article of Der Spiegel, a leading German weekly magazine. Based on these circumstances, I would like to suggest that the originally awarded Quercus robur be planted in Son keechung Memorial Park and that the newly discovered history be notified on the Seoul Metropolitan Government website and various records.

• Korean Journal of Optics and Photonics
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• v.33 no.5
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• pp.210-217
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• 2022

In this paper, a study is conducted on the acceptable tolerance of an alignment device to reduce the optical loss caused by the alignment tolerance of a window hermetic optical connector. To increase the transmission distance of optical signals and fiber-optic communication systems, it is necessary to maintain and improve the high optical efficiency of the connectors used to bond optical fibers. In the case of the window hermetic optical connector, the optical system is aligned through an alignment device. At this time, since the two connectors are used together, each component is fixed, and further alignment is impossible. The alignment tolerance of the housing system and pin used to align the optical system of the connector causes optical loss, leading to serious problems in the fiber-optic communication system. Thus, to find the acceptable tolerance required for manufacturing the optical-connector alignment device, tolerance analysis is performed on the components of the optical connector, such as the ball lens and the window. We also implement single-mode and multimode optical-connector systems, respectively. Based on the results, we determine an acceptable tolerance value for the alignment device.

• Composites Research
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• v.35 no.5
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• pp.322-327
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• 2022

Composite lap joints have been extensively used due to their excellent properties and the demand for light structures. However, due to the weak mechanical properties in the thickness direction, the lap joint is easily fractured. various reinforcement methods that delay fracture by dispersing stress concentration have been applied to overcome this problem, such as z-pinning and conventional stitching. The Z-pinning is reinforcement method by inserting metal or carbon pin in the thickness direction of prepreg, and the conventional stitching process is a method of reinforcing the mechanical properties in the thickness direction by intersecting the upper and lower fibers on the preform. I-fiber stitching method is a promising technology that combines the advantages of both z-pinning and the conventional stitching. In this paper, the static and fatigue strengths of the single-lap joints reinforced by the I-fiber stitching process were evaluated. The single-lap joints were fabricated by a co-curing method using an autoclave vacuum bag process and I-fiber reinforcing effects were evaluated according to adherend thickness and stitching angle. From the experiments, the thinner the composite joint specimen, the higher the I-fiber reinforcement effect, and Ifiber stitched single lap joints showed a 52% improvement in failure strength and 118% improvement in fatigue strength.