• Journal of Plant Biotechnology
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• v.40 no.4
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• pp.203-209
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• 2013

Genetic manipulation of pear (Pyrus pyrifolia Nakai) breeding is still difficult due to lack of reliable regeneration system. The aim of this research is to establish shoot regeneration system from leaf explants for pear (P. pyrifolia cv. Niitaka) using various concentrations of plant growth regulators and carbon source supplemented to medium. The highest regeneration rate of about 20% was found on a medium containing 4.4 g/L of Murashige and Skoog (MS) without vitamins, Linsmaier and Skoog (LS) vitamins were added separately. Leaf explants of pear were cultured on MS medium containing 7 g/L of Daishin agar supplemented with various concentrations of NAA (0.01, 0.05, 0.1, 0.5 mg/L) in combination with BA(3, 5, 10 mg/L) for shoot regeneration. In medium with 5 mg/L of BA and 0.01 mg/L of NAA, adventitious shoot regeneration rate was higher than others treated. The optimal results were observed using MS medium supplemented with 30 g/L sorbitol as carbon source on regeneration system. Sorbitol is considered better carbon source than sucrose for shoot regeneration of pear (P. pyrifolia cv. Niitaka). In order to increase of shoot regeneration in pear (P. pyrifolia cv. Niitaka), plant agar and Daishin agar used as gelling agents, Daishin agar is more efficient in shoot regeneration.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.84-90
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• 2006

This study was conducted to anticipate nitrate reduction state in tree through measurement of nitrate reductase activity (NRA) and investigate the effect of nitrogen concentrations (100, 200, 400, and 600 $mg\;L^{-1}$) on growth, the nitrogen content of various tissue, and NRA of pear (Pyrus pyrifolia cv. Niitaka) seedlings in sand culture. Nutrient solutions used in this experiment were adjusted to pH 6.5 and fixed the ratio of ammonium and nitrate to 1:3 and trickle-irrigated 3 times a day. Tree height and dry weight of various organs in seedlings were higher in low nitrogen concentration (100 and 200 $mg\;L^{-1}$) than in high nitrogen concentration (400 and 600 $mg\;L^{-1}$). The shoot growth in 600 $mg\;L^{-1}$ was extremely poor by nitrogen over supply. Increasing the nitrogen concentration, the concentration of nitrate-N in leaves and roots were insignificantly changed but that of stems increased. The accumulation of total and reduced nitrogen in all organs with increasing concentrations of nitrogen supply were increased at 30 days after treatment but those of all organs at 60 and 90 days after treatment were highest in 600 $mg\;L^{-1}$, whereas there were no significant changes among other nitrogen concentration. The in vivo (${+NO_3}^-$) NRA of all organs did not relate to nitrogen concentration but the in vivo (${-NO_3}^-$) NRA of leaves except roots increased with increasing the nitrogen concentration. Therefore, the proper nitrogen concentration to promote growth and nitrate reduction of pear tree was 200 $mg\;L^{-1}$.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.103-109
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• 2004

The term ton is widely used as the unit of the ship's size nowadays. Before people accepted the term ton as the unit of the ship's size, the various terms had been used for indicating the ship's size. For examples, the term ton was used in Western Europe, last in Northern Europe, cantara in Geneva, milliaria in Venice, and carra in Naple. In Asia the rice had been the most important cargo for many centuries. So the term SEOK in Korean or SHI in Chinese was used as the unit of the ship's size. Especially the Chinese used the term LIAO or RYO in Korean for indicating the ship's size. As above seen, the different terms had been used for showing the ship's size from places to places. But with the introduction of Moorsom's Tonnage Measurement in the 19th century and its spread to all over the world, the term ton was become the only unit of ship's size.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.339-345
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• 2004

The term ton is widely used as the unit of the ship's size. Before people used the term ton as the unit of the ship's size, the various terms had been used for indicating the ship's size. For examples, the term ton was used in Western Europe, last in Northern Europe, cantara in Geneva, milliaria in Venice, and carra in Naple respectively. In Asia the rice had been the most important cargo for many centuries. So the term SEOK in Korean or SHI in Chinese was used as the unit of the ship's size. Especially the Chinese used the term LIAO in Chinese or RYO in Korean for indicating the ship's size. As above seen, the different terms had been used for showing the ship's size from places to places. But with the introduction of Moorsom's Tonnage Measurement in the middle of the 19th century and its spread to all over the world, the term ton was become the only unit of ship's size.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.141-148
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• 2021

In this study, the technology to prevent lateral deformation of steel dampers was reviewed and applied to the clamp type dampers. As for the experimental method, the rocking behavior was applied as in the previous study. The evaluation variables are the existing research results (SV-260) without lateral deformation prevention details and the test results (V-1, V-1R) with lateral deformation prevention details. Where, V-1 is the lateral deformation prevention detail at the lower part of the damper, and V-1R is the lateral deformation prevention detail at the lower part and upper part of the damper. As a result of evaluating the moment, drift ratio, and energy dissipation capacity relative to SV-260 at the time of maximum load, the maximum moments of V-1 and V-1R were increased by 1.22 times and 1.36 times compared to SV-260, and the maximum drift ratio increased by 2.41 times and 2.92 times. In addition, the energy dissipation capacity also increased by 1.39 times and 1.52 times, respectively. Therefore, the application of lateral deformation prevention details to the steel damper was evaluated as appropriate.

• The Korean Journal of Malacology
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• v.29 no.3
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• pp.171-179
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• 2013

Arginine kinase (ArK) is known to play an important role in most invertebrates the level of ATP by phosphorylation of phosphagens in cell and immuninty in living organisms. ArK has been identified in many kinds of organisms ranging from invertebrate to vertebrate. However, no ArK gene has been cloned and investigated from N. samarangae. This leads us to identify ArK cDNA (NsArK) from the expressed sequence tag (EST) sequencing of N. samarangae. Sequence analysis indicated that the coding region of 1,065 bp contains 355 amino acid residues. Molecular phylogenetic analysis shows that NsArK had very high similarities with mollusca and arthropoda. In an attempt to investigate a potential role of NsArK in the digestive gland of N. samarangae, expression patterns were analyzed. RT-PCR analsysis shows that NsArK mRNA is induced in the rane of 1.2 fold at 6 hr by laminarin when compared with the control. The immunnologial and physiological role of NsArK remains to be further investigated in N. samarangae.

• Horticultural Science & Technology
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• v.30 no.2
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• pp.208-213
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• 2012

This study was performed to compare antioxidant activities of 80% EtOH extracts from young and mature fruit of three pear cultivars ('Wonhwang', 'Whangkeumbae', and 'Chuwhangbae') classified by three parts (peel, core, and flesh) of mature fruit. The total phenolics compound and flavonoid contents of 80% EtOH extracts from young fruit were 1.5-2.5 times higher than the mature fruit with great cultivar difference. In particular, the contents of those compounds were highest in 'Chuwhangbae' pear. The total phenolics compound and flavonoid contents of 80% EtOH extracts from mature fruit were the most in the peel, core, and flesh respectively. DPPH radical scavenging and $ABTS^+$ radical scavenging of 80% EtOH extracts from the young fruit were higher than the mature fruit of 'Chuwhangbae' pear. DPPH radical scavenging and ABTS+ radical scavenging of 80% EtOH extracts from mature fruit were the highest in the peel, core, and flesh respectively.

• Horticultural Science & Technology
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• v.19 no.1
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• pp.66-70
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• 2001

'Mansoo' is a late-season pear cultivar with extra large and high quality fruit of long storability, which was released by National Horticultural Research Institute in 1995. The cultivar originated from the cross between 'Danbae' and 'Okusankichi' at Suwon in 1978, had been under regional adaptability test at nine areas in the name of 'Wonkyo Na-15' for 4 years since 1992. It was vigorous in tree growth and upright in tree shape. Its flower bud is easily maintained, resulting in higher productivity than 'Danbae' and 'Okusankichi'. It bloomed a day later than 'Niitaka', and showed cross-compatibility with 'Niitaka', 'Chojuro' and some other varieties. Harvesting time of 'Mansoo' is late October in Suwon. The fruit shape is oblate and skin color is light yellowish brown. The fruit weighed 600-700 g and has 12-13% soluble solids content. The flesh is soft, juicy, and has negligible grit. It is resistant to black leaf rot (Alternaria kikuchiana Tanaka).

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.3
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• pp.263-278
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• 2022

This paper contains experimental study for the development and performance of TBM backfill material with thixotropic properties. The LW backfill material is widely applied to fill the cavity on the back side of the shield TBM excavation, but has disadvantages such as settlement caused by strength reduction, material separation by groundwater, and reduced plasticity. In this paper, laboratory tests and a model test were conducted to assess the performance of inorganic thixotropic backfill material proposed to improve these problems. The results of laboratory tests show that 1 hr-uniaxial compressive strength of ITB was 12 times higher than LW, and the rate of bleeding of 20 hr was 8.3 times lower, and the result of flow table test was more than 27 times higher. This result indicated that the inorganic thixotropic backfill material has superior properties to LW backfill in terms of strength reduction, material separation, and thixotropy. In the model experiment, a model injection device tester was manufactured and the injection performance and filling rate were verified. When material was injected in the water, it was visually checked whether material separation occurred, and it was confirmed that the filling rate was 96% or more. Comparison results with the test of LW and ITB materials was concluded that ITB can reduce the material separation by groundwater and the occurrence of tunnel cavity.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.170-175
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• 2015

The methanol extract of Asian pear (Pyrus pyrifolia N. cv. Chuhwangbae) fruit peel was purified using solvent fractionation, Sephadex LH-20 column chromatography, and octadecylsilane high performance liquid chromatography. Based on the electrospray ionization mass spectrometry and nuclear magnetic resonance data, the two isolated compounds were identified as quercetin 3-O-${\beta}$-D-glucopyranoside (1) and 3,5,6,7,8,3',4'-heptahydroxyflavan [(-)-dulcisflavan, 2]. Compounds 1 and 2 were isolated and identified for the first time from Asian pears and pears, respectively.