• Proceedings of the KWS Conference
• /
• 1996.10a
• /
• pp.54-55
• /
• 1996

• Journal for History of Mathematics
• /
• v.23 no.3
• /
• pp.1-20
• /
• 2010

Hong Jung Ha(洪正夏, 1684~?) is the greatest mathematician in Chosun dynasty and wrote a mathematics book Gu Il Jib(九一集) which excels in the area of theory of equations including Gou Gu Shu. The purpose of this paper is to find his influence on the history of Chosun mathematics. He belongs to ChungIn(中人) class and works only in HoJo(戶曹) and hence his contact to other mathematicians is limited. Investigating his colleagues and kinship relations including the affinity and consanguinity, we conclude that he gave a great influence to those people and find that three great ChungIn mathematicans Gyung Sun Jing(慶善徵, 1684~?), Hong Jung Ha and Lee Sang Hyuk(李尙爀, 1810~?) are all related through marriage.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.287-287
• /
• 2022

홍수빈도분석의 실용적 측면의 목적은 특정 재현기간에 대하여 발생 가능한 홍수량을 설계홍수량(design flood)으로 설정함으로써 댐, 제방, 배수시설, 하수관거 등의 치수기능을 가진 치수시설물이 설계홍수량 내에서 홍수로 인한 피해를 발생시키지 않도록 그 규모와 기능을 설계함에 있다. 특히 우리나라의 경우 유량자료의 부족으로 강우빈도분석을 수행하여 재현기간별 확률강우량을 먼저 산정하고 이를 강우-유출모형을 통해 확률홍수량으로 전환한 뒤 하천등급에 따른 재현기간 기준에 따라 설계홍수량을 산정하고 있다. 그러나 이와 같이 결정된 설계홍수량이 특정유역에서 발생될 수 있는 피해규모에 대해 얼마나 적정한 지의 여부를 과학적으로 판단하기 위한 연구는 국내·외에서 찾아보기 어려우며, 이러한 문제를 개선하기 위한 기초 이론을 제공하는 것이 본 연구의 가장 중요한 목표이다. 홍수빈도분석을 통해 산정된 설계홍수량의 적정성 여부를 과학적으로 판단하기 위해 최근에 진행된 해외의 몇몇 연구에서는 총 기대비용함수(total expected cost function)의 개발에 근거한 최적설계홍수량을 활용할 수 있음을 제안한 바 있다. 이 개념은 계획된 설계홍수량 이상에서 발생될 수 있는 피해함수(damage function) 및 기대피해함수(expected damage function)와 비용함수(cost function)가 결정되면, 이로부터 총 비용을 나타내는 총 기대비용함수(total expected cost function)을 도출하고 총 기대비용함수가 최소가 되는 최적설계홍수량(optimal design flood)을 산정하여 이를 계획된 설계홍수량(tentative design flood) 비교함으로써 계획된 설계홍수량의 적정성을 판단하는 과정을 기초이론으로 활용한다. 본 연구에서는 불확실성으로 발생되는 범위를 고려한 최적설계홍수량을 산정하기 위하여 Metropolis-Hastings 알고리즘을 사용하였으며, 자료의 종류에 따른 홍수량의 변화를 분석하기 위하여 년최대계열 및 부분시계열 자료를 각각 적용하였다. 한강유역에서 가평대성, 여주 및 한강대교 수위표 지점에서 측정된 자동관측유량장치에 의한 홍수량 자료를 활용하였으며, 최적설계홍수량이 기존 설계홍수량에 비해 크게 산정됨을 알 수 있었다.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.15 no.1
• /
• pp.1-8
• /
• 2013

This study was conducted to compare the local climate conditions and growth periods for the apple (Malus domestica 'Borkh') orchards at different altitudes (330, 500, and 670 m) in Jangsu-Gun, Korea. Observation data for the growth period show that the monthly mean air temperatures at the 'Hongro' apple orchard sites decrease with height at the rate of 1.0 to $3.0^{\circ}C$/100 m. The monthly minimum temperatures in April (blooming period for 'Hongro' apple) were 4.3, 2.9, and $0.4^{\circ}C$ at 330, 500, and 670 m, respectively. The monthly mean temperatures in September (i.e., the coloration and maturation period) were 20.6, 18.7, and $14.5^{\circ}C$, respectively. The annual precipitation range varied from 1,234 to 1,439 mm, which tended to increase with height. The heavy rainfall occurred in summer (June to August) and amounted to 827-933 mm. No significant differences in the duration of sunshine were observed amongst the orchards at three different altitudes. The earliest bud break was observed at the 330 m altitude (18 March 2009), which was 4 and 11 days earlier in comparison to those at 500 and 670 m, respectively. The time of full bloom at 330 m was 12 days ahead of that at 670 m. The optimal maturation of fruit (based on skin redness > 80%) was observed between 7 and 10 September at 330 m, 15 and 18 September at 500 m, and 21 and 23 September at 670 m.

• Journal of Bio-Environment Control
• /
• v.30 no.4
• /
• pp.320-327
• /
• 2021

Freezing damage to fruit trees is frequently occurring due to cold in winter and low temperature in spring to abnormal weather caused by global warming. In particular, the freezing injury of deciduous fruit trees is highly dependent on the developmental stages of the flower buds. And the cold resistance is weakened as the growth progresses, so it is most vulnerable period from flowering to petal fall(post-bloom). Therefore, this study was conducted to analyze the cause of the freezing injury caused by severe low temperature to 'Fuji', which has a late flowering period more than 'Hongro' in April 2020. We investigated freezing injury rate in 'Fuji' and 'Hongro' apple trees damaged by natural low temperature at Boeun-gun, Chungbuk province in Korea. In addition, flower buds in the same developmental stage (tight cluster) were treated artificially low temperature to investigate the injury rate for accurate comparative analysis between varieties, and to analyze the soluble sugar and hormone contents in the flower buds. As a result of survey in natural low temperature, 'Fuji' had a higher injury rate than 'Hongro' in both orchards, and in particular, B orchard 'Fuji' had the highest injury rate of 60.5%. Also there were significantly difference in the freezing injury rate between 'Fuji' and 'Hongro' in artificially low temperature treatments. As a result of analyzing the soluble sugar contents in 'Hongro' was higher than 'Fuji'. Also ABA, IAA and SA contents were more increased in the damaged tissue than in the normal flower buds by low temperature treatments. Consequently, it was assumed that the freezing injury was closely related to soluble sugar contents in the flower buds. In particular, the freezing injury rate was negatively correlated with the sorbitol contents.

• Journal of Bio-Environment Control
• /
• v.28 no.2
• /
• pp.126-133
• /
• 2019

In recent years, the deterioration of fruit quality caused by poor coloration and sunburn disorder has become serious problems in apple market, which is a result of the increase of surface temperature due to the abnormal temperature increase during summer season. This study was conducted to investigate the effect of wind net shading and fine water spray using sprinkler on fruit coloration, sunburn damage and overall fruit quality of 'Fuji' and 'Hongro' apples. Fifteen sprinklers (7L/hr) were installed at the orchard of the Chungcheongnam-do Agricultural Research and Extension Services, located in Sinam-myeon Chungcheongnam-do Korea, at a height of 3m above the apple tree of $1.5m{\times}3.5m$ north-south direction. Fine water spraying treatment was divided into day time spray (10:00 am to 6:00 pm) and all day spray (10:00 am to 10:00 pm) from early July to 10 days before harvest in 2017 and 2018 season, respectively. Temperature of the surface of apple fruit, characteristic of fruit, and degree of sunburn damage were investigated. In 'Fuji', the fruit surface temperature checked at 2 pm on August 10 was decreased considerably in the day time spray ($35.6^{\circ}C$) and wind net ($39.0^{\circ}C$) when compared with the untreated control ($44.4^{\circ}C$). Similarly, the fruit surface temperature also decreased considerably in the all day spray ($35.1^{\circ}C$) and wind net ($36.9^{\circ}C$) treatments when compared with the untreated control ($46.5^{\circ}C$) in 'Hongro' apples. The incidence of sunburn disorder was significantly decreased with day time spray (5.0%), all day spray (5.8%) and wind net (7.0%) when compared with untreated control (23.4%) in 'Fuji' apples. As a results, the treatment of fine water spray and wind net consequently showed 26% and 34% increase of redness ($a^*$) value in the skin color difference, respectively, in 'Fuji' apples.

• Journal of Life Science
• /
• v.28 no.6
• /
• pp.681-687
• /
• 2018

Recently, several researchers have been developing cosmetics from natural ingredients for skin whitening and anti-aging products. The red sea cucumber (RSC), Apostichopus japonicas, is a species of sea cucumber in the family stichopodiae, which is widely distributed in China, Japan, and Korea. To use Red Sea Cucumber as a cosmetic ingredient, its inhibitory effects on melanogenesis and the anti-aging effects of RSC extracts were investigated. First, a tyrosinase activity assay was performed, which showed that RSC inhibited tyrosinase activity at a concentration of $200{\mu}g/ml$. An MTT assay was carried out to evaluate cell toxicity, and the results showed that RSC extract has no cytotoxicity in HaCaT cells. Furthermore, the mRNA expression levels of tyrosinase, tyrosinase related protein 1 (TRP-1), tyrosinase related protein 2 (TRP-2), microphthalmia-associated transcription factor (MITF), and matrix metalloproteinase (MMPs) genes treated with RSC extract in B16F10 and HaCaT cells decreased. Moreover, a wound-healing assay was performed to identify the cell regeneration effect of RSC extracts. Also, a skin turnover effect was confirmed by creating a three-dimensional cell culture with HaCaT and human fibroblasts. Altogether, the results suggested that Red Sea Cucumber may possess a high ability to induce whitening and anti-wrinkle effects as a cosmeceutical ingredient.

• Korean Journal of Weed Science
• /
• v.30 no.4
• /
• pp.454-459
• /
• 2010

This study was conducted to investigate the phytotoxic reaction and the impact on the growth of apple fruit included the yield amount by misuse of non-selective herbicide, glufosinate-ammonium in apple field and for the study, 4 cultivars of apple were tested. The results showed that the highest phytotoxic degree was observed on Sansa-cultivar and then the degree was diminished on Tsugaru, Hongro and Fuji in order in the application year. In one year after application, the highest phytotoxic degree was showed on Fuji and then diminished on Tsugaru, Hongro and Sansa in order. However, in one year after application, the phytotoxic symptom was negligible in comparison with the degree in the year of application and the flowering and fruiting were reduced 30% only in Fuji, but in the other cultivars, the phytotoxic symptoms were not observed. Meanwhile, the residue of glufosinate-ammonium was below the detection limit as 0.04ppm in all tested cultivars and in 2years after application, the phytotoxic symptom was not observed in all cultivars of the apple.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.9
• /
• pp.1302-1307
• /
• 2005

In this study, we investigated the anticarcinogenic and antioxidative activities of Rhodiola sachalinensis (RS). Hexane (RSMH), ethylether (RSMEE), ethylacetate (RSMEA), butanol (RSMB), aqueous (RSMA) fractions and methanol extract (RSM) were screened for their growth inhibition effects using 3- (4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay on HepG2, HeLa, MCF-7 and HT-29 cells. The anticarcinogenic effects of RSMEE was most significant when tested on MCF-7 and HepG2 cell lines at the concentration of $500{\mu}g/mL$ which resulted about $84\%\;and\;90\%$ on MCF-7 and HepG2 cells, respectively. The quinone reductase (QR)-inducing activity of RSMH on HepG2 cells was 3.5 times higher compared with the control at the concentration of $200{\mu}g/mL$. Antioxidative activities of RSM, RSMEE, RSMEA and RSMB showed about $80\%$ of electron donating activity (EDA) which were very similar to that of vitamin C as a control. We observed morphological changes of shrinking and the blebbing of HepG2 cancer cell membranes depending on the concentration of RSMEE.

• The Korean Journal of Pesticide Science
• /
• v.16 no.4
• /
• pp.302-307
• /
• 2012

This study was carried out to elucidate residual characteristics of environment friendly agricultural material rotenone in chilli pepper and calculate processing factors by drying. The test material was sprayed twice onto chilli peppers at an interval of seven days and then the chilli peppers were harvested at 0, 1, 3, 5 and 7 days after final spray. Limits of quantitation (LOQs) of rotenone in fresh and dried chilli peppers were 0.03 and 0.07 mg/kg, respectively. Recoveries of the test material in fresh and dried chilli peppers ranged from 89.52 to 97.86% and from 85.76 to 91.61%, respectively. As a results of residual material analysis, amounts of rotenone in fresh and dried chilli peppers ranged from 0.03 to 0.39 mg/kg and from 0.07 to 0.75 mg/kg, respectively, representing that the residual amounts of rotenone decreased time-coursely. Processing factors of rotenone in fresh chilli pepper by drying were found to be from 2.03 to 3.13, indicating that the residual concentration of rotenone in dried chilli pepper increased from two to three times by drying. However, the reduction factor of rotenone in fresh chilli pepper by drying ranged from 0.38 to 0.59, representing that some of rotenone in fresh chilli pepper disappeared during the drying process.