• KIEE International Transactions on Electrophysics and Applications
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• 제4C권2호
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• pp.45-50
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• 2004

The field utilization factor (equation omitted) (the mean electric field / the maximum electric field) of standard sphere gaps was calculated by the charge simulation method, taking into account the ground plane and shanks. n changes mainly with g/r and slightly with 1$_1$, 1$_2$ and 1, where D=2r is the sphere diameter, g is the gap length, 1$_1$ and 1$_2$, respectively, are the lengths of the upper and lower shank, and t is the shank diameter. Generally, (equation omitted) increases as 1$_1$,1$_2$ and t each becomes larger. IEC standard 60052(2002) limits t$\leq$0.2D 1$_1$$\geq$1D and prescribes A=1$_2$＋D＋g where A is the height of the spark point on the upper sphere. Therefore, (equation omitted) is the largest when A=9D and the smallest when A=3D. The simple equation of a straight line, (equation omitted)=1- (g/3r), can generally be used as a representative value of (equation omitted) for a wide variety of sphere diameters that are permitted by the IEC standard. The maximum electric field E$_{m}$ at sparkover of standard air gaps has also been calculated by the relation E$_{m}$=V/(equation omitted)g). E$_{m}$ describes a U-curve for g/r, up to the sphere diameter of 1 m. Moreover, for 1.5-m and 2-m diameters and especially .for negative polarity, sparkover voltages have been calculated by integration of the ionization index.index.

• 기술혁신학회지
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• 제8권1호
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• pp.277-295
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• 2005

The objective of the study is to verify the discriminatory power of valuation indexes in predicting IT small and medium sized manufacturing firms' going concern or firms' failure. The result of the study is expected to be useful in loan evaluation, investment decision, internal management decision making and business improvement. The results of study is as follows. First, we find that at least six valuation index elements are significant ex-ante variable which are discriminating between firms' going concern and firms' failure in IT small and medium sized manufacturing firms in various analysis' results. Second, these index elements are composed of 2 indexes-the ability of technology R&D, the efficient strategy of market penetration and six index elements explain 46% of the total variance. This explainable power of these indexed is similar to that of the existing 16 index elements. Finally, we find that the most important success factor of IT small and medium sized manufacturing firms are the ability of technology R&D and the efficient strategy of market penetration.

• 화약ㆍ발파
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• 제15권3호
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• pp.20-32
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• 1997

The pressure-time profile of the explosion gases can be controlled fot the use of cartridge explosives with two techniques Known as Decoupling and Spacing the charges. Decoupling consists in leaving and empty space between the explosive column and wall of the blast hole. Four different decoupling index, 1.4, 1.8, 2.34, 3.0 are selected in this field study. The level of ground vibrations with each decoupling index are measured and the empirical particle vibrations with each decoupling index are measured and the empirical particle velocity equation from these data was obtained. The condition of new cracks at blast hole are also examined. As the decoupling index in increased, the level of the blast vibration is decreased,. But the cracks in rock masses are efficiently formed to remove the broken rock. The vibration constant associated with a given site $K=1564.5(D.I)^{-1.3233}$ in terms of D.I(decopling index).

• Journal of applied mathematics & informatics
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• 제27권1_2호
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• pp.267-273
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• 2009

A representation for the Drazin inverse of an arbitrary square matrix in terms of the eigenprojection was established by Rothblum [SIAM J. Appl. Math., 31(1976) :646-648]. In this paper perturbation results based on the representation for the Darzin inverse $A^D\;=\;(A-X)^{-1}(I-X)$ are developed. Norm estimates of $\parallel(A+E)^D-A^D\parallel_2/\parallel A^D\parallel_2$ and $\parallel(A+E)^#-A^D\parallel_2/\parallel A^D\parallel_2$ are derived when IIEI12 is small.

• Environmental Engineering Research
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• 제23권1호
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• pp.21-27
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• 2018

Air pollution index (API) is used in Mainland China and includes only $SO_2$, $NO_2$ and $PM_{10}$. In 2016, air quality index (AQI) replaced API. AQI contains three more air pollutants (CO, $O_3$ and $PM_{2.5}$). Both the indices emphasize on the effect of a single pollutant, whereas the contributions of all other pollutants are ignored. Therefore, in the present work, a novel air quality index (NAQI), which emphasizes on all air pollutants, has been introduced for the first time. The results showed that there were 19 d (5.2%) in API, 28 d (7.7%) in AQI and 183 d (50.1%) in NAQI when the indices were more than 100. In API, $PM_{10}$ and $SO_2$ were regarded as the primary pollutants, whereas all five air pollutants in AQI were regarded as primary. Furthermore, four air pollutants (other than the CO) in NAQI were regarded as primary pollutants. $PM_{10}$, as being the primary pollutant, contributed greatly in these air quality indices, and accounted for 51.2% (API), 37.0% (AQI) and 52.6% (NAQI). The results also showed that particulate matter pollution was significantly high in Luzhou, where stricter pollution control measures should be implemented.

• 한국산림과학회지
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• 제113권2호
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• pp.187-197
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• 2024

본 연구에서는 콕스 비례위험모형을 이용하여 산불피해 소나무의 고사에 영향을 미치는 인자를 밝히고자 하였다. 지표화 피해 소나무를 대상으로 고사 영향 인자를 조사하고 산불 발생 7년 차까지 고사 발생 모니터링을 수행하였다. 수집된 자료를 기반으로 생존분석을 실시하였다. 분석 결과, 고사 위험성을 증가시키는 변수는 dNDVI(delta Normalized Difference Vegetation Index), dNBR(delta Normalized Burn Ratio), 경사, 나무에 남겨진 그을음의 상대적인 면적과 평균적인 높이를 나타내는 수피 그을음 지수(Bark Scorch Index, BSI)와 수피 그을음 높이(Bark Scorch Height, BSH)로 나타난 반면, 음의 관계를 가지는 변수는 고도, 흉고직경, 수관층 수분스트레스 변화를 나타내는 수분스트레스지수(dleta Moisture Stress Index, dMSI)로 나타났다(p<0.001). 콕스 비례위험모형의 유의성을 확인하기 위한 변수별 비례위험가정검증에서는 사면방향을 제외한 모든 인자가 모형에 적합하며 고사 발생에 유의미한 영향을 미치는 것으로 나타났다. 생존 곡선 분석에서 가장 큰 생존율 차이를 보인 변수는 BSI였으며(p<0.0001), 원격탐사를 통해 얻어진 환경변화 인자들(dNDVI, dNBR, dMSI) 역시 큰 생존율 차이를 나타내었다(p<0.0001). 이러한 결과는 산불 이후 소나무의 잠재적인 고사위험성을 고려한 복원계획 수립을 위한 기초자료로 활용될 것으로 기대된다.

• 한국잡초학회지
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• 제1권1호
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• pp.78-83
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• 1981

한국(韓國)의 야생(野生)잔디가 재식(栽植)되에 있는 잔디밭을 대상(對象)으로 문제잡초구명(問題雜草究明) 및 잡초방제방법구명시험(雜草防除方法究明試驗)에서 얻어진 결과(結果)를 요약(要約)하면 다음과 같다. l. 본(本) 조사지역(調査地域)에서 발생(發生)된 잡초종류(雜草種類)는 40여종(餘種)이었고 발생빈도(發生頻度) 및 발생량(發生量) 면(面)에서 크로바, 바랭이, 방동산이, 망초, 꽃다지 등이 문제(問題)의 잡초(雜草)로 구명(究明)되었다. 2. 경산(慶山) 칸트리클럽 주변(周邊)의 조사지점(調査地點)에서는 크로바, 바랭이, 꽃다지, 방동산이, 망초 등이 공존(共存)하는 군락형(群落型)으로 Simpson's Index가 0.306이었고 경북대(慶北大) 캠펴스내(內)의 조사지점(調査地點)에서는 Simpson's Index가 0.776으로 주로 크로바가 우점(優占)하는 군락형(群落型)을 보였다. 전체(全體)의 건물중(乾物重) 증가양상(增加樣相)에는 두 지역간(地域間)에 시간적(時間的) 차이(差異)는 있으나 유사(類似)하였다. 3. 크로바와 광엽잡초(廣葉雜草)가 우점(優占)하는 지역(地域)에 MCPP 3.4kg (a.i.)/ha를 2회(回) 처리(處理)는 경미한 약해(藥害)가 있기는 하나 84.1%의 높은 방제효과(方劑효果)를 나타냈으며 MCPP 2.2~2.8kg (a. i.)/ha 처리(處理)도 약해(藥害)는 전혀 없으며 높은 방제효과(方劑效果)를 나타냈다. 4. 2,4-D 성분량(成分量)으로 2.0kg/ha 처리(處理)는 MCPP 3.4kg (a.i.)/ha 에 준(準)한 방제효과(方劑效果)를 나타내지는 못하였으나 높은 방제율(防除率)을 보였으며 약해(藥害)를 고려(考慮)할 때 2,4-D 1.0kg (a.i.)/ha 정도면 광엽잡초방제(廣棄雜草防除)에 유효(有效)할 것이다.

• 한국주조공학회지
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• 제23권5호
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• pp.235-243
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• 2003

The collapsibility of sodium silicate-bonded sands mixed with the L.D converter slag powder to form a hardener were investigated. Five to six percent sodium silicate on the basis of silica sand and 30-40% L.D converter slag powder on the basis of sodium silicate, were mixed and the compressive strength, surface stability index(SSI), bench time, retained strength of the standard sand specimens were measured. The properties were similar to those of general inorganic bonded self-setting molds. The compressive strength and surface stability index were increased and the retained strength and bench time were decreased with increased amount of the L.D converter slag powder. The retained strength of sodium silicate-bonded self-setting molds with the L.D converter slag powder were decreased than $CO_2$ sand molds. The collapsibility of sodium silicate-bonded self-setting molds with the L.D converter slag powder were superior in comparison with $CO_2$ sand molds. The L.D converter slag powder could be used as hardener and collapse agent for the sodium silicate-bonded self-setting molds.

• 대한지역사회영양학회지
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• 제9권4호
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• pp.528-535
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• 2004

In order to observe the effects of resistant starches on human glycemic response, nine female university students were investigated using cellulose (CED), resistant starch 3 (RS3D) and resistant starch 4 (RS4D) diets. Each woman's blood sugar and insulin, triacylglycerol and free fatty in plasma concentration were measured at fasting state, then 15, 30, 45, 60, 75, 90 and 120 minute after each test diet feeding. Glycemic indices of the Cellulose diet (CED: 57.9 $\pm3.00$), the Resistant starch 3 diet (RS3D: 52.6 $\pm7.9$) and the Resistant starch 4 diet (RS4D: 52.9 $\pm10.2$) were similar to each other, but they were significantly lower in comparison with those of white wheat bread diet (WWBD: 100). Insulinemic indices of the CED (49.8 $\pm8.2$), RS3D (50.0 $\pm7.3$) and RS4D (72.4 $\pm7.7$) were significantly lower in comparison with the white wheat bread diet (WWBD: 100), but among the dietary fiber diets, the insulinemic index of RS4D was significantly higher than the CED and the RS3D. Plasma triacylglycerol contents of the CED, RS3D and RS4D including WWBD showed gradual increase in tendency after lowering in early stage of each test diet feeding, but not significantly different in each dietary fiber added diet. Plasma free fatty acid contents of the CED, RS3D and RS4D including WWBD showed gradual decrease in tendency after each test diet feeding, but not significantly different by each dietary fiber added diet. In above results, we speculate that resistant starch 3 controls rapid elevation of blood sugar by delaying intestinal digestion and absorption of cellulose, but the result appears to be different from RS4 in comparison. Thus, RS3 intakes may contribute to the diet therapy of diabetic humans, but more studies on RS4 is needed in the future. (Korean J Community Nutrition 9(4): 528∼535, 2004)

• 대한소아치과학회지
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• 제8권1호
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• pp.103-117
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• 1981

The data about dental caries obtained from 1438 preschool children (male 797, female 641) in Seoul aged from 3 to 6 were analyzed by their sexes, ages, jaws and teeth surfaces. The results were as follows. 1. dmf rate : 92.63% 2. dmft index : 6.06 dmft rate 30.81 % dmfs index : 11.82 dmfs rate 12.02 % 3. d,m & f rate d rate: 79.45% m rate: 8.15% f rate : 12.40 % 4. dft index : 5.94 5. The order of caries susceptible tooth 1. Lower deciduous 2nd molar 2. Lower deciduous 1st molar 3. Upper deciduous 2nd molar 4. Upper deciduous lateral incisor 5. Upper deciduous cental incisor 6. Upper deciduous lateral incisor 7. Lower deciduous canine 8. Upper deciduous canine 9. Lower deciduous central incisor 10. Lower deciduous lateral incisor 6. Predilection sites of each tooth A) Deciduous central incisor ; Max. : Mesial cavity Mand. : Mesio-distal cavity B) Decidous lateral incisor ; Max. : Mesial cavity Mand. : Distal cavity=Mesial cavity C) Deciduous canine; Max. : Labial cavity Mand. : Distal cavity D) Decidous 1st molar ; Max. : Disto-occlusal cavity Mand.: Disto-occlusal cavity E) Deciduous 2nd molar ; Max. : Linguo-occlusal cavity Mand.: Occlusal cavity 7. All the values in caries criteria in 1981 were somewhat lower than in 1968, but m & f rate were increased.