• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.319-320
• /
• 2012

Large aperture optical modulator called optical shutter is a key component to realize time-of-flight (TOF) based three dimensional (3D) imaging systems [1-2]. The transmission type electro-absorption modulator (EAM) is a prime candidate for 3D imaging systems due to its advantages such as small size, high modulation performance [3], and ease of forming two dimensional (2D) array over large area [4]. In order to use the EAM for 3D imaging systems, it is crucial to remove GaAs substrate over large area so as to obtain high uniformity modulation performance at 850 nm. In this study, we propose and experimentally demonstrate techniques for backside etching of GaAs substrate over a large area having high uniformity. Various methods such as lapping and polishing, dry etching for anisotropic etching, and wet etching ([20%] C6H8O7 : H2O2 = 5:1) for high selectivity backside etching [5] are employed. A high transmittance of 80% over the large aperture area ($5{\times}5mm^2$) can be obtained with good uniformity through optimized backside etching method. These results reveal that the proposed methods for backside etching can etch the substrate over a large area with high uniformity, and the EAM fabricated by using backside etching method is an excellent candidate as optical shutter for 3D imaging systems.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.15 no.2
• /
• pp.132-139
• /
• 1995

This experiment was canied out to select the soybean of high productivity suited for soiling. and growth characterisitcs, palatability, dry matter and crude protein yield of 10 cultivars of soybean have been evaluated at the experimental forage field. College of Natural Science of Kon-Kuk University in Chungju over three years (1 989-1 09 1 ). The results obtained are summarized as follows: JangBaek showed the tallest plant length from the 70th day to 80th day during cultivation period. and BaekUn showed the tallest at 90th day. PalDal among all cultivars showed the fastest growth rate and the strongest resistant lodging during cultivation period. The stem diameter of 70th day showed highly in order of PalDal and HwangKeum > BaekUn > KwangKyo and JangYeob, the 80th day showed highly in the order of TogYu > BaekCheon > JangBaek and 90th day showed highly in order of BangSa > BaekCheon > JangYeob. Stem hardness was highly increased with increasing of cultivation period, but no significant difference were found among the soybean cultivan. Especially, BaekUn and TogYu of 90th day showed very high as 17.9 and 17.6 kg/cm2, respectively. In the number of branch, PalDal was the lowest during cultivation period(70, 80 and 90th day), and 90th day showed lower two and three times than other soybeans(P<0.05). In the leaf rate, BaekCheon showed the highest according to cultivation period and the lowest in JangBaek. The fresh yield was tended to increase by increasing cultivation period at all cultivars except KwangKyo, but no significant differences were found among cultivars. Dry matter yield of JangYeob was the highest as 5, 861 kg/ ha at 70th day, and that of KwangKyo and TogYu was the highest as 7, 471 and 10, 603 kgha at 80th and 90th day, respectively. Relative palatability of 70th days showed very high at all soybean cultivars(81-100%), and that of 80th and 90th day showed the highest at TogYu, while showed the lowest at PalDal. In crude protein content of the 70th, 80th and 90th day, DanYeob, JangYeob and HwangKeum were the highest as 20.1, 17.9 and 20.4 percentage, respectively. Crude protein yield during cultivation period showed the highest at JangYeob(7Oth : 1, 068, 80th : 1, 211, 90th : 1, 882 kglha), but showed the lowest at BangSa(70th : 61 1, 80th : 814, 90th : 1, 078 kg/ha).

• Journal of the Korea Society for Simulation
• /
• v.20 no.2
• /
• pp.67-76
• /
• 2011

Order picking in automotive service parts warehouses is considered to be the most labor-intensive operation. Such warehouses contain hundreds of thousands of items, but normally 20% of products contribute to about 80% of turnover according to Pareto's 80-20 principle. Therefore most fast moving items are located near an outbound area which is called the "Golden Zone". Order picking routing efficiency is related to productivity and labor cost. However, most companies use simple methods. In this paper, we describe a series of computational experiments over a set of test cases where, we compared various previously existing routing heuristics to an optimal algorithm. We focus on examining the influence of the golden zone on the performance and selection of routing methods. The results obtained show that the optimal routing method increases the productivity at least 17.2%, and all the routing methods have better performance as the pick up rate from the golden zone increases.

• Journal of the East Asian Society of Dietary Life
• /
• v.13 no.5
• /
• pp.408-424
• /
• 2003

The purpose of this study was to analyze the nutritional status and dietary habits in predialysis patients of chronic renal failure(CRF). The patients group was composed of total 35 persons with chronic renal failure(diabetes exclusion), male 20, female 15 who were treated in the kidney internal department and the control group also composed of 35 persons, male 18, female 17 who were classified as normal by the medical examination. Their dietary habits, nutritional status and nutritional knowledge were investigated from two general hospitals in Inchon, middle of this year 2002. There were 31.4% of low weight patients (BMI below 20), 77.1% of anemia patients (serum hemoglobin below 12g/㎗), 6S.6% of hypertension patients with diastolic blood pressure over 90mmHg, 80% with systolic blood pressure over 140mmHg, 20% of hypercholesterolemia patients (serum cholesterol over 230mg/㎗), and 22.9% of hyperlipemia patients (serum triglyceride over 200mg/㎗). The cardiovascular disease seemed to be caused by the abnormality of lipid metabolism. The possibility of the bone disease was shown from patients of hyperphosphatemia (serum phosphorus over 4.7mg/㎗, 22.9%) and hypocalcemia (serum calcium below 8.4mg/㎗, 25.7%). Intake of insufficient calories which was caused by the lack of appetite affected on the nutritional status. The intake of most nutrients was not significantly different from the RDA for Koreans. Consequently, the patient groups took a lot of salt even after the diagnosis of CRF. But patients ate 6.lg of salt which were more than the recommended amount 2∼4g for patients with CRF. The patient groups, who had the experiences of nutritional counselling, had significantly higher nutritional knowledge related to CRF than control group. Unfortunately, patients could not have enough chances for nutritional counselling by the nutritionist even though they needed the nutritional informations and dietetic treatments. The continuous research is expected with regard to the detail plan for the improvement of nutritional support and the nutritional counselling because it is important to decide the requirements of nutrients for patients with kidney disease, considering the kidney function and status of nutrition.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.6
• /
• pp.2223-2235
• /
• 2013

This study aimed to understand temporal and spatial trends of rainfall characteristics in South and North Korea. Daily rainfall observed at the 65 stations in South Korea between 1963 and 2010 and the 27 stations in North Korea between 1973 and 2010 were analyzed. Rainfall Indicators for amount, extremes, frequency of rainfall were defined. Province-based indicators in the recent 10 years (i.e., between 2001 and 2010) were compared to those in the past (i.e., between 1963/1973 and 2000 for South/North Korea). In the recent 10 years, all the indicators except for the number of wet days (NWD) and 200-yr frequency rainfall (Freq200) increased in South Korea and all the indicators except for the annual mean daily rainfall over wet days (SDII) and annual total rainfall amount (TotalDR) decreased in North Korea. Furthermore, we performed the Mann-Kendall trend test based on the annual indicators. In some stations, decreasing trends in the past and increasing trends in the recent 10 years were found, and such opposite trends between two periods suggest he limitation in predicting and analyzing the rainfall characteristics based on the average. Results from this study can be used in analyzing the impact of climate change and preparing adaptation strategies for the water resources management.

• Economic and Environmental Geology
• /
• v.19 no.spc
• /
• pp.227-237
• /
• 1986

The Duk-Eum mine located in Kongsan-myeon, Naju-gun, Cheolanamdo is producing silver ore mainly, with rare gold association. The grade-up and recovery of the concentrates have been concerned to the main problem. And then, this study aimed at applying the basic data for ore processing. In the first half of the study, the attempts were made to identify the ore minerals, this followed by determination of the mineral texture, paragenesis, grain size, and size distribution by employing the microscopical method and the etching test. The results of the study are as follows: 1. The ore deposit is composed of the hydrothermal fissure linked veins, and filling cavities are mostly tensile fractures or joints, in rhyolitic rocks as a wall rock. 2. The principle ore minerals are native silver, acanthite, canfieldite, pyrargyrite, galena, tetrahedrite, sphalerite, pyrrhotite, chalcopyrite, chalcocite, covellite, zincite, and the gangue minerals are quartz and calcite. 3. The grain size of each ore minerals before grinding are; max. $2\frac{1}{2}$ mesh, medium 48-100 mesh(main size, contained over 80%), min. 3200mesh. And the grain size of each ore minerals after grinding is; max. 42mesh, medium 65-250mesh(main size, contained over 80%), min. 3200mesh. 4. The properties of the mineral texture effected on the ore dressing are follows; a) Inclusion texture; the fine grains of chalcopyrite is included in most acanthite, and rarely, that of galena included in acanthite. b) Exsolution texture; pyrargyrite is exsolved in acanthite. c) Replacement texture; native silver replaced pyrargyrite, and acanthite replaced galena. d) Interlocking paragenetic texture; the interlocking paragenetic minerals are pyrite, chalcopyrite, chalcocite, canfieldite. e) Fissure filling texture; chalcopyrite was filled along the cracks in acanthite. Among of the above texture, it is impossible to liberate the grains of a), and more difficult to liberate those of b) and c), while easy to liberate those of d) and e).

• Atmosphere
• /
• v.19 no.2
• /
• pp.213-226
• /
• 2009

In order to investigate the characteristics of Changma over the Korean peninsula, KEOP-2007 IOP (Intensive Observing Period) was conducted from 15 June 2007 to 15 July 2007. KEOP-2007 IOP is high spatial and temporal radiosonde observations (RAOB) which consisted of three special stations (Munsan, Haenam, and Ieodo) from National Institute of Meteorological Research, five operational stations (Sokcho, Baengnyeongdo, Pohang, Heuksando, and Gosan) from Korea Meteorological Administration (KMA), and two operational stations (Osan and Gwangju) from Korean Air Force (KAF) using four different types of radiosonde sensors. The error statistics of the sensor of radiosonde were investigated using quality control check. The minimum and maximum error frequency appears at the sensor of RS92-SGP and RS1524L respectively. The error frequency of DFM-06 tends to increase below 200 hPa but RS80-15L and RS1524L show vice versa. Especially, the error frequency of RS1524L tends to increase rapidly over 200 hPa. Systematic biases of radiosonde show warm biases in case of temperature and dry biases in case of relative humidity compared with ECMWF (European Center for Medium-Range Weather Forecast) analysis data and precipitable water vapor from GPS. The maximum and minimum values of systematic bias appear at the sensor of DFM-06 and RS92-SGP in case of temperature and RS80-15L and DFM-06 in case of relative humidity. The systematic warm and dry biases at all sensors tend to increase during daytime than nighttime because air temperature around sensor increases from the solar heating during daytime. Systematic biases of radiosonde are affected by the sensor type and the height of the sun but random errors are more correlated with the moisture conditions at each observation station.

• Microbiology and Biotechnology Letters
• /
• v.49 no.1
• /
• pp.45-56
• /
• 2021

Improved amylases were developed from protoplast fusants of two amylase-producing Aspergillus species. Twenty regenerated fusants were screened for amylase production using Remazol Brilliant Blue agar. Crude enzyme extracts produced by solid state fermentation of rice bran were assayed for activity. Three variable factors (temperature, pH and enzyme type) were optimized to increase the amylase activity of the parents and selected fusants using rice bran medium and solid state fermentation. Analysis of this optimization was completed using the Central Composite Design (CCD) of the Response Surface Methodology (RSM). Amylase activity assays conducted at room temperature and 80℃ demonstrated that Aspergillus designates, T5 (920.21 U/ml, 966.67 U/ml), T13 (430 U/ml, 1011.11 U/ml) and T14 (500.63 U/ml, 1012.00 U/ml) all exhibited improved function making them the preferred fusants. Amylases produced from these fusants were observed to be active over the entire pH range evaluated in this study. Fusants T5 and T14 demonstrated optimal activity under acidic and alkaline conditions, respectively. Fusants T13 and T14 produced the most amylase at 72 h while parents TA, TC and fusant T5 produced the most amylase after 96 h of incubation. Response surface methodology examinations revealed that the enzyme from fusant T5 was the optimal enzyme demonstrating the highest activity (1055.17 U/ml) at pH 4 and a temperature of 40℃. This enzyme lost activity with further increases in temperature. Starch hydrolysis using fusant T5 gave the highest yield of glucose (1.6158 g/100 ml). The significant activities of the selected fusants at 28 ± 2℃ and 80℃ and the higher sugar yields from cassava starch hydrolysis over their parental strains indicate that it is possible to improve amylase activity using the protoplast fusion technique.

• Nutrition Research and Practice
• /
• v.14 no.4
• /
• pp.374-383
• /
• 2020

BACKGROUNDS/OBJECTIVES: To describe the data-based development of a food frequency questionnaire (FFQ) for dietary evaluation of Korean preschool children. SUBJECTS/METHODS: Development of the FFQ was based on the data from 2,766 preschool children aged 1-5 years, who had completed 24-hour dietary recalls in the 2009-2013 Korea National Health and Nutrition Examination Survey. We selected the food list based on the results of nutritional contribution and between-person variability for energy and 13 nutrients. We selected 88 foods with over 80% of total contribution to each nutrient and with over 80% of accumulated r² for each nutrient. A dish containing any of the 88 foods in the recipe was listed, and a total of 903 dishes were extracted. Among the 903 dishes, we selected 438 dishes contributing more than 1% of total consumption. RESULTS: FFQ included 116 dish items combined from 438 dishes based on nutrient profile and recipe. Quantities of dietary intake were assessed by nine categories of frequency and portion size option. In addition, when comparing the food portions of children with the reference portion size, subjects would be asked to select one of three response categories (less, similar, and more) and then to record the amount as a percentage for the reference portion. Percentages of coverage for energy, protein, fat, and carbohydrate were 89.2%, 88.4%, 88.2%, and 89.4%, respectively. CONCLUSIONS: The dietary intake of Korean preschool children can be assessed by this new data-based FFQ. In addition, the new instrument can be used to identify nutritional needs of target groups for planning nutrition education and strategies to improve diet. Further studies are warranted to evaluate the performance of the instrument.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.1
• /
• pp.76-80
• /
• 2008

Reductive acetylation of a variety of carbonyl compounds such as aldehydes, ketones and a,b-unsaturated enals/enones was carried out efficiently with pyridine zinc borohydride, (Py)Zn(BH4)2, in a mixture of THF-EtOAc at room temperature or under reflux condition. The corresponding acetates were obtained in high to excellent yields. In addition, chemoselective reductive acetylation of aldehydes over ketones was achieved perfectly with the reagent at room temperature.