• Transactions on Electrical and Electronic Materials
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• v.3 no.4
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• pp.5-9
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• 2002

Chemical mechanical polishing (CMP) has become the preferred planarization method for multilevel interconnect technology due to its ability to achieve a high degree of feature level planarity. Especially, to achieve the higher density and greater performance, shallow trench isolation (STI)-CMP process has been attracted attention for multilevel interconnection as an essential isolation technology. Also, it was possible to apply the direct STI-CMP process without reverse moat etch step using high selectivity slurry (HSS). In this work, we determined the process margin with optimized process conditions to apply HSS STI-CMP process. Then, we evaluated the reliability and reproducibility of STI-CMP process through the optimal process conditions. The wafer-to-wafer thickness variation and day-by-day reproducibility of STI-CMP process after repeatable tests were investigated. Our experimental results show, quite acceptable and reproducible CMP results with a wafer-to-wafer thickness variation within 400$\AA$.

• Child Health Nursing Research
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• v.10 no.3
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• pp.282-290
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• 2004

Purpose: The measure the degree of computer game addiction; to examine the relationship between computer game addiction and contributing factors; and to discover the predictors of computer game addiction of elementary school children of Korea. Method: Data were assembled from questionnaires distributed among 455 children from four elementary schools in Gyung-buk Province. Result: The level of computer game addiction of subjects was rather low, and correlated significantly with gender, academic performance, family economic status, playmates for leisure time, place of playing computer game, length of the habit of playing game, average playing time of game per day, frequency of PC-room(Internet Cafe for game) visits per week, game partners and reasons for playing game. Multiple regression analysis showed that 45％ of the computer game addiction was significantly related to gender(21％), impulsiveness(10％), average playing time of game per day(9％), depression(2％) and other variables(3％) such as playmates for leisure time, academic performance and frequency of PC-room visits per week. Conclusion: We suggest these results be used to develop a computer game addiction prevention program.

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.658-664
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• 2015

Lens designers generally refer to flat image fields and attempt to minimize the field curvature. Present-day CMOS image sensors for mobile phone cameras, however, are not flat, but curved. Sometimes it is necessary to generate an intentional field curvature according to the degree and direction of the CMOS image-sensor’s curvature. This paper presents the degree of curvature of a CMOS image sensor measured using an interferometer, and proposes an effective compensation method that minimizes the net field curvature through optimizing the air gap between lens elements, which is demonstrated using simulations and experiments.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.638-643
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• 1994

Gelatinization and retrogradation properties of modified starches which were prepared by steeping sweet potato at $40^{\circ}C$ for 2, 4, 7 and 10 days were investigated. The peak temperature of gelatinization and enthalpy of untreated starch by DSC were $53.9^{\circ}C\;and\;1.32\;cal/g$, respectively, but those of modified starch were increased by steeping. In gelatinization by alkali, starches with 2, 4 and 7 day steeping showed higher viscosities than untreated starch, whereas the viscosities of starches with 10 day steeping decreased. The clarities in paste decreased during storage in all starches and decreased in starches with steeping. The degrees of retrogradation by ${\alpha}-amylase-iodine$ method were higher in starches with steeping than untreated starch. The enthalpy of retrograded starches by DSC increased by steeping except 4 day steeping starch. The sweet potato extract containing sugar inhibited the retrogradation of starch paste and the degree were higher in residual starches than in untreated starch.

• Korean journal of applied entomology
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• v.35 no.2
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• pp.119-125
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• 1996

Temperature-dependent development study for overwintered eggs of Pseudococcus comstocki (Kuwana) wasconducted to develop a forecasting model for egg hatch date. Hatch times of overwintered eggs were comparedat five constant temperatures (10, 15, 20, 25, 27$^{\circ}$C) and different collection dates. A nonlinear, four-parameterdevelopmental model with high temperature inhibition accurately described (R2=0.9948) mean developmentalrates of all temperatures. Variation in developmental times was modeled(~~=0.972w9)it h a cumulative Weibullfunction. Least-squares linear regression (rate=O.O06358[Temp.]-0.07566)d escribed development in the linearregion (15-25$^{\circ}$C) of the development curve. The low development threshold temperature was estimated 11.9"Cand 154.14 degree-days were required for complete development. The linear degree-day model (thermal summation)and rate summation model (Wagner et al. 1985) were validated using field phenology data. In degreedaymodels, mean-minus-base method, sine wave method, and rectangle method were used in estimation of dailythermal units. Mean-minus-base method was 18 to 28d late, sine wave method was 11 to 14d late, rectanglemethod was 3 to 5d late, and rate summation model was 2 to 3d late in predicting 50% hatch of overwinteredeggs. hatch of overwintered eggs.

• Journal of Technologic Dentistry
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• v.9 no.1
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• pp.67-72
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• 1987

This experimental study presented the study on the dimensional changes of occuring for the denture curing methods. The method is as follows: 1. The master die was made of wax. 2. The Silicon Rubber Mold was made into the same 80 casts. 3. The 80 Wax Plate were made of using the Base Plate Wax. 4. Flasking, Wax-wash, & Resin-packing were performed by the general procedures. 5. The curing method is performed through the four curing methods. (A, B, C, D). Table 2 shows the dimensional change after a day. Table 3 shows the dimensional change after soaking for 30 days in water of the degree of 36 Centigrade. As a result, the A curing method is the most denture curing.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.3
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• pp.252-261
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• 2018

This study was conducted to develop a method to generate daily maximum and minimum temperatures using monthly data. We analyzed 30-year daily weather data of the 23 meteorological stations in South Korea and elucidated the parameters for predicting annual trend (center value ($\hat{U}$), amplitude (C), deviation (T)) and daily fluctuation (A, B) of daily maximum and minimum temperature. We use national average values for C, T, A and B parameters, but the center value is derived from the annual average data on each stations. First, daily weather data were generated according to the occurrence of rainfall, then calibrated using monthly data, and finally, daily maximum and minimum daily temperatures were generated. With this method, we could generate daily weather data with more than 95% similar distribution to recorded data for all 23 stations. In addition, this method was able to generate Growing Degree Day(GDD) similar to the past data, and it could be applied to areas not subject to survey. This method is useful for generating daily data in case of having monthly data such as climate change scenarios.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.3
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• pp.451-461
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• 1993

Four hundred and eighty broiler chicks of both sexes were obtained from commercial hatchery (Hubbard) and raised on floor pens. All chicks were allowed free access to food from 0 to 7 and 20 to 56 days of age. At 7 days of age, all broilers were weighed individually, and divided into five groups as follows: 1. feed ad libitum as the control; 2. allowed free access to food 3 days and starved 1 day ($3{\times}1$); 3. allowed free access to food 2 days and starved 1 day ($2{\times}1$); 4. allowed free access to food 1 day and starved 1 days ($1{\times}1$) and; 5. allowed free access to food 2 days and starved 2 days ($2{\times}2$). Broilers were restricted for 12 days (d 7 through 17) of a 56-day trial. Broilers were fed a commercial starter diet (crude protein 23.8% and ME 3,070 kcal/kg) for 21 days, and commercial finisher diet (crude protein 20% and ME 3,160 kcal/kg) from 22 to 56 days of age. Although there was compensatory growth in some groups, (the $1{\times}1$ female group, and the $3{\times}1$ and $2{\times}1$ male grous), its level was not sufficient to achieve normal body weight at market age. There was sexual dimorphism for accelerated growth as well as differences in the ability to achieve a complete compensation of growth to the weight, feed conversion ratio, and body composition of ad libitum chicks. Early feed restriction could be used to reduce production cost because of the lower fed conversion ratio, mortality rate and the amount of starter diet consumed by broilers. The response of chicks to early feed restriction might depend on the degree of feed restriction, the method of feed restriction, duration of feed restriction, and sexes.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.772-779
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• 2005

Ammonia-oxidizing bacteria (AOB) were enriched by repeating fed-batch cultivations in an AOB-selective medium of activated sludges from a domestic wastewater treatment plant. Enriched culture showed strong capabilities of ammonia oxidation [0.810 mg $NH_4^+$-N/mg mixed liquor suspended solids (MLSS)$\cdot$day] as well as $NO_x^-$-N production (0.617 mg $NO_x^-$-N/ mg MLSS$\cdot$day). Degree of enrichment was examined through fluorescent in situ hybridization (FISH) analyses using an AOB-specific Cy3-labeled oligonucleotide probe (NSOl90) and terminal-restriction fragment length polymorphism (T-RFLP) analyses. FISH analyses confirmed that the fraction of AOB among 4',6-diamidino-2-phenylindole (DAPI)-stained cells increased from about less than $0.001\%$ to approximately $42\%$ after enrichment of AOB, and T-RFLP analyses showed that bacterial community became simpler as enrichment was continued. When the enriched culture of AOB was added (150 mg/l as dry suspended solid) to the normal activated sludge (3,000 mg/l as dry suspended solid), nitrification efficiencies were improved from 0.020 mg $NO_x^-$-N/mg MLSS$\cdot$day to 0.041 mg $NO_x^-$-N/mg MLSS$\cdot$day in a synthetic wastewater and also from 0.0007 mg $NO_x^-$-N/mg MLSS$\cdot$day to 0.0918 mg $NO_x^-$-N/mg MLSS$\cdot$day in a real domestic wastewater. Therefore, it is expected that this enrichment method could be used for improving efficiency of nitrification in wastewater treatment plants.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.11 no.3
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• pp.256-264
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• 2004

Purpose: This study was to identify the effects of self-administered hand reflexology on level of fatigue in college student nurses during clinical practice. Method: A non-equivalent control group, quasi-experimental research with pre and post-test design was used. Forty-seven student nurses in clinical practice were assigned to either an experimental or control group. The experimental group performed self-hand reflexology for 10 minutes once a day during the 5 days of clinical practice. Results: 1. While there was a significant difference in degree of fatigue and fatigue scores in the experimental group over time, there was no significant difference between the two groups. 2. Vigor score for the experimental group was significantly higher than those of the control group during the 5 days except for day 5, but there was no significant difference between the two groups. 3, Levels of fatigue for the experimental group increased after 1 hour in the 1st post time, but there was no significant difference between the groups. Conclusion: Self-administered hand reflexology was not found to be an effective method for relieving fatigue for student nurses in clinical practice. Also physiological effects were not identified in this study, and so further research is needed.