• The Korean Journal of Pesticide Science
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• v.17 no.2
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• pp.107-116
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• 2013

Polar pesticides like pymetrozine (log $P_{ow}$: -0.18) are known to be difficult to analyze. The analytical method of pymetrozine using hydromatrix included in the official method of KFDA was uncommon and provided ambiguous evidence to confirm both the identity and the quantity. Therefore, precise single residue analytical method was developed in representative crops for using liquid-liquid extraction (LLE). The pymetrozine residue was extracted with methanol from 11 representative crops which comprised apple, blueberry, broccoli, cabbage, cherry, crown daisy, hulled rice, Korean cabbage, potato, rice and watermelon. The extract was purified serially by liquid-liquid extraction (LLE) and silica solid phase extraction (SPE). For rice and hulled rice samples, n-hexane partition was additionally adopted to remove nonpolar interferences, mainly lipids. The residue levels were analyzed by HPLC with DAD, using $C_8$ column. LOQ (limit of quantitation) of pymetroizinie was 1 ng (S/N > 10) and MQL (method quantitation limit) was 0.01 mg/kg. Mean recoveries from 11 crop samples fortified at three levels (MQL, 10 ${\times}$ MQL and 50 ${\times}$ MQL) in triplicate were in the range of 83.1~98.5% with coefficients of variation (CV) of less than 10%, regardless of sample type, which satisfies the criteria of KFDA. The method established in this study could be applied to most of crops as an official and general method for analysis of pymetrozine residue.

• Journal of Nutrition and Health
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• v.6 no.3
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• pp.37-45
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• 1973

The main character of the Korean diet has been found to be low in protein both quantity and quality and high in carbohydrate. The purpose of this survey was to study the amount of salt intake related to the dietary pattern in Korea. The nutrition survey was conducted in a mountainous farming area located in Auhchun-ri, Gaebuk-myon, Changsoo-gun, Chunbuk Province, February 14-19 in 1973 (7 days). The precise weighing method was used in evaluating the kinds of foods and nutrients intake for 24 households during a three day period. The physical examinations were performed by a doctor on 120 persons and a detailed biochemical test on both blood and urine was made on 42 persons over 40 years old. The results obtained are summarized as follows: (1) Average nutrients intake of an adult per day: calorie intake was 2,446 Cal and its components-protein(61.1g) was 10 percent, fat(12.9g) was 5 percent and carbohydrate(521g) contributed 85 percent of the total calories. Other nutrients-calcium (443mg), thiamine(1.09mg), riboflavin (0.90mg), niacin (14.4mg) and vitamin C (63.2mg) were lower than the recommended daily allowance but vitamin A(2,083 I.U.), iron(11mg) and phosphorous(998mg) were slightly higher than that. (2) To evaluate the nutritional deficiences, clinical examinations were conducted. Angular stomatitis was present in 16.7 percent of those examiners. No edema was found. The rate of osteoarthritis, hepatomegaly diseases appeared in 20 percent of the total subjects and the symptoms appeared highest among those Iron 50 to 59 years old. (3) The following chemical components of blood serum were analyzed and found to be within the normal range: glucose, blood urea nitrogen, uric acid, total protein, albumin, globulin, bilirubin, total cholesterol, inorganic phosphate, alkaline phosphatase, sodium, potassium, chloride, calcium and lecithine dehydrase. One case of each of the following were found: hyperglycemia, hypocholesterolemia, renal problem, hypoproteinaemia and diabetes mellitus, and two persons were classified as showing hypoglycemia and hyponaturemia. (4) The sodium content in urine was 199.6 mEq/L, potassium content was 24.6 mEq/L. The sugar, pH and specific gravity in the urine was shown to be normal.

• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.321-331
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• 2006

Recently, runoff characteristics of urban area are changing because of the increase of impervious area by rapidly increasing of population and industrialization, urbanization. It needs to extract the accurate topologic and hydrologic parameters of watershed in order to manage water resource efficiently. Thus, this study developed more precise input data and more improved parameter estimating procedures using GIS(Geographic Information System) and GA(Genetic Algorithm). For these purposes, XP-SWMM (EXPert-Storm Water Management Model) was used to simulate the urban runoff. The model was applied to An-Yang stream basin that is a typical Korean urban stream basin with several tributaries. The rules for parameter estimation were composed and applied based on quantity parameters that are investigated through the sensitivity analysis. GA algorithm is composed of these rules and facts. The conditions of urban flows are simulated using the rainfall-runoff data of the study area. The data of area, slope, width of each subcatchment and length, slope of each stream reach were acquired from topographic maps, and imperviousness rate, land use types, infiltration capacities of each subcatchment from land use maps, soil maps using GIS. Also we gave the management scheme of urbanization runoff using XP-SWMM. The parameters are estimated by GA from sensitivity analysis which is performed to analyze the runoff parameters.

• Tunnel and Underground Space
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• v.27 no.1
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• pp.50-57
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• 2017

In this study, the experiment for determining shock loss at the branch is conducted for the design of network double-deck road tunnel ventilation. The shock loss coefficient that determines the quantity of shock loss has been considered only regarding the constant aspect ratio of circular or rectangular section. However the suggestion of shock loss coefficient is needed since the aspect ratio of double-deck road tunnel for small vehicle is considered around 1:3 with the low height in Korea. The experiment model was made with the scale of around 1:23 applying Reynolds similarity law, so that the shock loss coefficient on the branch of the large aspect ratio was measured. The result of the study showed that shock loss coefficients of both split branch and straight branch were measured two to three times higher than those calculated from the theoretical equation or design values of previous studies. Therefore the study resulted the effect of large aspect ratio on shock loss coefficient was huge, and it is expected that precise design value can be suggested for the design of network double-deck tunnel ventilation.

• Analytical Science and Technology
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• v.14 no.3
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• pp.244-252
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• 2001

A comprehensive analytical method of endocrine distruptors[i.e., nonylphenol(NP), octylphenol(OP), bis(2-ethylhexyl)phthalate(BEHP)] is fish samples was developed using two internal standards. This method employed closed culture tube extraction with dichloromethane and solvent exchange to iso-hexane and SPE(2g) aminopropyl column, followed by determination on gas chromatograph linked to mass spectrometer(GC/MS) operated in the single ion monitoring(SIM) mode. The recoveries of nonylphenol and octyphenol in the range of $0.2{\sim}20{\mu}g/g$ using 1-phenyl decanol as one internal standard were over 75%, and recovery of bis(2-ethylhexyl)phthalate in the range of $0.4{\sim}40{\mu}g/g$ using bis(2-ethylbutyl)phthalate(BEBP) as the other internal standards was showed over 102%. The present method was applied to fish samples from Korea and UK. The range of concentrations for nonylphnol(NP) and bis(2-ethylhexyl)phthalate in Korean fish were $0.02{\sim}0.06{\mu}g/g$ in 2 samples and $0.18{\sim}2.03{\mu}g/g$ in 9 samples respectively, but bis(2-ethylhexyl)phthalate(BEHP) in UK samples was found $2.99{\mu}g/g$ in just 1 sample. But octylphenol(OP) was not dected in any samples by this method. This two internal standard method provides a more precise analytical tool to investigate endocrine disruptors in a biological matrices of limited quantity.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.1
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• pp.1-11
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• 2005

Several Solid Freeform Fabrication Systems(SFFS) are commercialized in a few companies for rapid prototyping. However, they have many technical problems including the limitation of applicable materials. A new method of agile prototyping is required for the recent manufacturing environments of multi-item and small quantity production. The objectives of this paper include the development of a novel method of SFFS, the CAFL/sup VM/(Computer Aided Fabrication of Lamination for Various Material), and the manufacture of the various material samples for the certification of the proposed system and the creation of new application areas. For these objectives, the technologies for a highly accurate robot path control, the optimization of support structure, CAD modeling, adaptive slicing was implemented. However, there is an important problem with the conventional 2D lamination method. That is the inaccuracy of 3D model surface, which is caused by the stair-type surface generated in virtue of vertical 2D cutting. In this paper, We design the new control algorithm that guarantees the constant speed, precise positioning and tangential cutting on the 5DOF SFFS. We develop the tangential cutting algorithm to be controlled with constant speed and successfully implemented in the 5DOF CAFL/sup VM/ system developed in this paper. Finally, this paper confirms its high-performance through the experimental results from the application into CAFL/sup VM/ system.

• Korean Journal of Construction Engineering and Management
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• v.19 no.3
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• pp.3-10
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• 2018

In recent years, mechanized construction has become commonplace due to increases in the scale and complexity of construction, and construction machinery is a major factor in successful construction. However, even though the proportion of construction machinery is increasing, analysis of the work capacity of construction machinery is inadequate. In addition, since the standards for all construction machines are currently not defined in quantity-per-unit, the construction period is arbitrarily applied according to the operator at the time of the construction plan. As a result, the construction period of the actual construction is insufficient, and rushed work or construction delays occur. Therefore, in this study, in order to calculate the construction period of the piling work of the pile driver used in the PRD method more accurately than the existing method, the formula for calculating the time required for the piling work of the pile driver was established by collecting piling time data from the daily task reports through the field survey. If the precise construction period of piling work is estimated based on the results of this study, it will be possible to prevent the rushed work and construction delays that occur due to the short construction period.

• Journal of the Korean Society of Food Culture
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• v.34 no.5
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• pp.508-533
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• 2019

This study investigated the Sachanbalgi, which record the royal feasts given by the royal family of the Joseon Dynasty of Korea. These records are contained within the Gungjung Balgi, which recorded the types and quantity of items used in royal court ceremonies. The Eumsikbalgi is the general name for the records of food found within this document. Using these Eumsikbalgi, and in particular the Sachanbalgi, this study investigated the food eaten and bestowed by the Joseon royal family. The Sachanbalgi describes four categories or occasions of feasts: royal birthdays, childbirth, royal weddings, and funerals. These records allow us to reconstruct who the attendees were and what the table settings and food were for instances not directly indicated in oral records, books, or other documents. The food at these Sachan (feasts) was diverse, being related to the specific event, and its contents varied based on the position of the person who was receiving the food. Usually, Bab (rice) was not found at a Sachanbalgi, and only on two occasions were meals with Bab observed. Specifically, it was served with Gwaktang (seaweed soup) at a childbirth feast. There were seven kinds of soups and stews that appeared in the Sachanbalgi: Gwaktang, Yeonpo (octopus soup), Japtang (mixed food stew), Chogyetang (chilled chicken soup), Sinseonro (royal hot pot), and Yukjang (beef and soybean paste). Nureumjeok (grilled brochette) and Saengchijeok (pheasant), and Ganjeonyueo (pan-fried cow liver fillet) and Saengseonjeonyueo (pan-fried fish fillet) were eaten. Yangjeonyueo, Haejeon, Tigakjeon (pan-fried kelp) and other dishes, known and unknown, were also recorded. Boiled meat slices appeared at high frequency (40 times) in the records; likewise, 22 kinds of rice cake and traditional sweets were frequently served at feasts. Five kinds of non-alcoholic beverages were provided. Seasonal fruits and nuts, such as fresh pear or fresh chestnut, are thought to have been served following the event. In addition, a variety of dishes including salted dry fish, boiled dish, kimchi, fruit preserved in honey, seasoned vegetables, mustard seeds, fish, porridge, fillet, steamed dishes, stir-fried dishes, vegetable wraps, fruit preserved in sugar, and jellied foods were given to guests, and noodles appear 16 times in the records. Courtiers were given Banhap, Tanghap, Myeonhap, wooden bowls, or lunchboxes. The types of food provided at royal events tracked the season. In addition, considering that for feasts food of the royal household was set out for receptions of guests, cooking instructions for the food in the lunchbox-type feasts followed the cooking instructions used in the royal kitchen at the given time. Previous studies on royal cuisine have dealt mostly with the Jineosang presented to the king, but in the Sachanbalgi, the food given by the royal family to its relatives, retainers, and attendants is recorded. The study of this document is important because it extends the knowledge regarding the food of the royal families of the Joseon Dynasty. The analysis of Sachanbalgi and the results of empirical research conducted to reconstruct the precise nature of that food will improve modern knowledge of royal cuisine.

• Atmosphere
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• v.34 no.2
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• pp.203-216
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• 2024

The National Institute of Meteorological Sciences in Korea has developed the Weather Modification Hybrid Rocket (WMHR), an advanced system that offers enhanced stability and cost-effectiveness over conventional solid-fuel rockets. Designed for precise operation, the WMHR enables accurate control over the ejection altitude of pyrotechnics by modulating the quantity of oxidizer, facilitating specific cloud seeding at various atmospheric layers. Furthermore, the rate of descent for pyrotechnic devices can be adjusted by modifying parachute sizes, allowing for controlled dispersion time and concentration of seeding agents. The rocket's configuration also supports adjustments in the pyrotechnic device's capacity, permitting tailored seeding agent deployment. This innovation reflects significant technical progression and collaborations with local manufacturers, in addition to efforts to secure testing sites and address hybrid rocket production challenges. Notable outcomes of this project include the creation of a national framework for weather modification technology utilizing hybrid rockets, enhanced cloud seeding methods, and the potential for broader meteorological application of hybrid rockets beyond precipitation augmentation. An illustrative case study confirmed the WMHR's operational effectiveness, although the impact on cloud seeding was limited by unfavorable weather conditions. This experience has provided valuable insights and affirmed the system's potential for varied uses, such as weather modification and deploying high-altitude meteorological sensors. Nevertheless, the expansion of civilian weather rocket experiments in Korea faces challenges due to inadequate infrastructure and regulatory limitations, underscoring the urgent need for advancements in these areas.

• Journal of Soil and Groundwater Environment
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• v.29 no.4
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• pp.32-43
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• 2024

Recently, numerous earthquakes have caused significant casualties and property damage worldwide, including major events in 2023 (Türkiye, M7.8; Morocco, M6.8) and 2024 (Noto Peninsula, Japan, M7.6; Taiwan, M7.4). In South Korea, the frequency of detectable and noticeable earthquakes has been gradually increasing since the M5.8 Gyeongju Earthquake. Notable recent events include those in Jeju (M4.9), Goesan (M4.1), the East Sea (M4.5), and Gyeongju (M4.0) since 2020. This study, for the first time in South Korea, monitored groundwater levels and temperatures at a 1Hz frequency to observe the responses in groundwater to moderate and small earthquakes primarily occurring within the country. Between April 23, 2023, and May 22, 2023, 17 earthquakes were reported in the East Sea region with magnitudes ranging from M2.0 to M4.5. Analysis of groundwater level responses at the Gangneung observation station revealed fluctuations associated with five of these events. The 1Hz observation data clearly showed groundwater level changes even for small earthquakes, indicating that groundwater is highly sensitive to the frequent small earthquakes recently occurring in South Korea. The analysis confirmed that the maximum amplitude of groundwater level changes due to earthquakes is proportional to the earthquake's magnitude and the distance from the epicenter. These findings highlight the importance of precise 1Hz-level observations in earthquake-groundwater research. This study provides foundational data for earthquake monitoring and prediction and emphasizes the need for ongoing research into monitoring the changes in groundwater parameters (such as aquifer characteristics, quantity/quality, and contaminant migration) induced by various magnitudes of earthquakes that may occur within the country in the future.