• Environmental Engineering Research
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• 제20권3호
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• pp.260-267
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• 2015

The $PM_{10}$, $SO_2$ and $NO_2$ mass concentrations were obtained over five years from monitoring stations across Nanchong, a southwest city in China. Changes in urban air quality over time, as well as the factors influencing that change, were evaluated based on air pollutant concentrations, the Air Pollution Index (API), and the Comprehensive Pollution Index (P). The results showed that the total annual mean $PM_{10}$, $SO_2$ and $NO_2$ concentrations over the five years studied were $61.1{\pm}1.1$, $45.0{\pm}3.9$ and $34.9{\pm}4.9{\mu}g{\cdot}m^{-3}$, respectively. The annual mean concentrations displayed a generally decreasing trend; lower than the annual mean second-level air quality limit. Meanwhile, the annual mean API values were in a small range of 52-53, the air quality levels were grade II, and P values were 1.06-1.21 less than the slight level ($P{\leq}1.31$). Total monthly mean $PM_{10}$, $SO_2$, $NO_2$ concentrations, and API and P values were consistently higher in winter and spring than during autumn and summer. The results of a correlation analysis showed that temperature and pressure were the major meteorological factors influencing pollution levels. Pollution sources included industrial coal and straw burning, automobiles exhaust and road dust, fireworks, and dust storms.

• 대한지역사회영양학회지
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• 제15권5호
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• pp.694-703
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• 2010

Recent studies have reported that a subset of obese individuals who were metabolically healthy but obese had more favorable clinical outcomes than obese subjects with metabolic disturbances. The purpose of this study was to evaluate the distribution and agreement of obesity subtypes according to body mass index (BMI) and metabolic syndrome (MS). Furthermore, we examined the differences of nutrient intake among the groups. Data was analyzed for 1,095 female subjects older than 40 years using Korean National Health and Nutrition Survey in 2008. The degree of obesity was classified by two methods, using BMI (obese ${\geq}\;25\;kg/m^2$, not obese < $25\;kg/m^2$) and MS (meet ${\geq}\;3$ criteria among 5 index: waist circumference, triglyceride, glucose, HDL-cholesterol and blood pressure). Subjects were divided into 4 groups according to $2{\times}2$ cross table: non-obese without MS, non-obese with MS, obese without MS and obese with MS. Nutrient intakes were compared among 4 groups. The results showed that the proportions of non-obese without MS, non-obese with MS, obese without MS and obese with MS were 47.6%, 13.6%, 16.6%, and 22.2% of total subjects, respectively. The agreement (kappa value) of two methods was 0.354 (fair) in total subjects, 0.365 (fair) in 40-60 year old subjects and 0.304 (fair) in ${\geq}\;61$ year old subjects. In ${\geq}\;61$ years old subjects, intakes of percentage energy from carbohydrate, percentage of energy from fat, calcium, phosphorous, sodium, vitamin A, carotene, thiamine, riboflavin and niacin were significantly different among the groups. In contrast, the subjects of 40-60 years old, no differences in nutrient intakes were observed. In conclusion, there were differences in nutrient intakes among the groups subdivided by obesity and MS, especially in elderly female subjects. Individualized dietary guideline for subtype of obesity will be needed to treat metabolic disturbance of obesity.

• 한국지반공학회지:지반
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• 제2권3호
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• pp.51-66
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• 1986

본 연구는 재래식 옹벽의 단점을 보완하여 skin element로써 간단한 L-type concrete block을 사용하고 reinforcing strip재로써 plastic fabric strip를 이용하며, back fill재는 우리 주위에서 흔히 접하는 나강암풍화토를 사용하여 만든 보강벽체를 통하여 몇가지 실험을 한 결과 이들 서반재료의 특성을 발안하여 개발된 이론식에 의하여 결정한 벽체의 보강은 삽입한 strip의 간격, 층수, 뒷채움 재의 입도분포, 다짐상태 및 strip의 인장강맥에 좌우되며 본보강옹벽체는 구조적으로 안정하고 경제적인 시공이 가능함이 확인되었으며 우리나라 특히 강원도와 같은 유간지역에서는 보다 효과적으로 이용될 수 있을 것으로 판단된다.

• Journal of Ecology and Environment
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• 제46권1호
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• pp.76-84
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• 2022

Background: Climate and livestock grazing are key agents in determining current Mongolian steppe vegetation communities. Together with plant coverage or biomass, palatability of steppe community is regarded as a useful indicator of grassland degradation, in particular, at grazing hotspots in arid and semi-arid grasslands. This study analyzed relationships between livestock grazing pressure and steppe vegetation palatability at three summer pastures with different aridity (dry, xeric, and mesic) and livestock numbers (1,100, 1,800, and 4,100 sheep units, respectively). At each site, it was surveyed coverage, biomass, and species composition of different palatability groups (i.e., palatable [P], impalatable [IP], and trampling-tolerant [TT]) along a 1-km transect from grazing hotspots (i.e., well) in every July from 2015 to 2018. Results: In results, total vegetation coverage increased with wetness, 7 times greater at mesic site than dry one in averages (33.1% vs. 4.5%); biomass was 3 times higher (47.1 g m^-2 vs. 15.7 g m^-2). Though P was the dominant palatability group, the importance of IP in total coverage increased with aridity from mesic (0.6%) to dry (40.2%) sites. Whereas, TT increased with livestock numbers across sites. Locally, IP was observed more frequently near the wells and its spatial range of occurrence becomes farther along the transects with aridity across sites from mesic (< 100 m) to dry (< 700 m from the well). Conclusions: Our results showed that the importance of IP and its spatial distribution are different at both local and regional scales, indicating that the palatability parameters are sensitive to discern balance between selective-grazing demand and climate-driven foraging supply in Mongolian rangelands.

• Wind and Structures
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• 제27권1호
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• pp.11-27
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• 2018

The straight-cone steel cooling tower is a novel type of structure, which has a distinct aerodynamic distribution on the internal surface of the tower cylinder compared with conventional hyperbolic concrete cooling towers. Especially in the extreme weather conditions of strong wind and heavy rain, heavy rain also has a direct impact on aerodynamic force on the internal surface and changes the turbulence effect of pulsating wind, but existing studies mainly focus on the impact effect brought by wind-driven rain to structure surface. In addition, for the indirect air cooled cooling tower, different additional ventilation rate of shutters produces a considerable interference to air movement inside the tower and also to the action mechanism of loads. To solve the problem, a straight-cone steel cooling towerstanding 189 m high and currently being constructed is taken as the research object in this study. The algorithm for two-way coupling between wind and rain is adopted. Simulation of wind field and raindrops is performed with continuous phase and discrete phase models, respectively, under the general principles of computational fluid dynamics (CFD). Firstly, the rule of influence of 9 combinations of wind sped and rainfall intensity on flow field mechanism, the volume of wind-driven rain, additional action force of raindrops and equivalent internal pressure coefficient of the tower cylinder is analyzed. On this basis, the internal pressures of the cooling tower under the most unfavorable working condition are compared between four ventilation rates of shutters (0%, 15%, 30% and 100%). The results show that the 3D effect of equivalent internal pressure coefficient is the most significant when considering two-way coupling between wind and rain. Additional load imposed by raindrops on the internal surface of the tower accounts for an extremely small proportion of total wind load, the maximum being only 0.245%. This occurs under the combination of 20 m/s wind velocity and 200 mm/h rainfall intensity. Ventilation rate of shutters not only changes the air movement inside the tower, but also affects the accumulated amount and distribution of raindrops on the internal surface.

• 한국방사선학회논문지
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• 제1권3호
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• pp.35-40
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• 2007

본 연구에 참여한 대상자는 서산시에 거주하는 자로 2007년 1월 1일부터 2007년 11월 31일까지 본원에 내원한 환자 중 방사선 경추 전 후면, 측방향 촬영을 실시하여 총 113명(40세 이하)을 대상으로 조사하여 다음과 같은 결과를 얻었다. 1) 연령의 분포는 14~40세 까지로 남자 57명(50.4%), 여자 56명(49.6%)이었으며, 연령그룹이 30~40세 80명(70.8%), 20~29세 27명(23.9%)에서 많은 빈도를 나타냈다. 2) 경부통의 발생 원인으로는 교통사고, 실족, 원인 모름이 대부분으로 조사 되었는데 원인 알 수 없음이 81명(71.7%)으로 가장 많이 나타났으며, 증상 발현되는 시기는 만성 87명(77%)적으로 발현되는 것으로 나타나 경부통의 발생원인과 증상발현과의 통계적 유의성이 있는 것으로 나타났다. 3) 전체 113명 중 20~29세 27명(23.9%), 30~40세 80명(70.8%)로 증상발현이 급성, 만성 모두 높은 분포를 보였다. 4) 본 연구자는 전체 113명 중 왼쪽 견부 39명(34.5%), 경추부위 31명(27.4%), 양쪽 견부 20명(17.7%)에서 각각 주요 통증이 있음을 알 수 있었고, 측만된 방향으로는 왼쪽측만 62명(54.9%)이 가장 많은 빈도로 나타났다. 5) 전 후 만곡방향에서 전만곡 48명(42.5%)으로 나타났으며, 수축기 혈압에서는 160mmHg에서 전만곡 19명(16.8%), 이완기 혈압에서는 총 69명(61.0%)이 전만곡 31명(27.4%)이 100mmHg으로 나타났다.

• Preventive Nutrition and Food Science
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• 제2권4호
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• pp.338-347
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• 1997

Apo E polymorphism(e2, e3, e4) was among the first reported genetic polymorphism that explained part of the normal vairation in plasma cholesterol concentrations. Both alleles E2 and E4 are significantly more frequent in patients with mixed forms of hyperlipidemia and contribute on the observed differences in CHD risk among different populations. Effects of apo E polymorphism on the distribution of plasma lipid profiles were studied in 89 normolipidemic healthy females, aged 19 up to 22 years. The relative frequencies of E3/3 was 0.787, E3/2 was 0.101, E3/4 allele was 0.112 and no E2/2, E2/4 and E4/4 were found. Weight, height and %LBM were elevated in E2 than those in E3&E4. No differences in the blood pressure among apo E isomers were found, otherwise the pulsation was higher in E4 than that in the others. There were no differences in plasma total-, total DL-, HDL$_3$-, HDL$_2$ cholesterol, apo B-100 and apo A-I, However, phenotype means rank E3/2>E3/3>E3/4 in average TG levels(p<0.0001) significantly, and rank E3/4>E3/3>E3/2 in LDL cholesterol levels. These results were related to the correlation between atherogenic indiced (AI) such as LDL/HDL, (TC-HDL)/HDL, HDL$_3$/HDL$_2$. The ratio of HDL$_3$& HDL$_2$was significantly increased in E2 & E4 than that in E3(P=0.043). LCAT activity was not different between E2 and E3 but was highly increased in E4 (p<0.0001 among apo E isomers), but CETP was not different. Since the negative correlation between LCAT and CETP in apo E2(r=-0.491) was stronger than that in apo E3, E2 allele impacts the clearance of plasma apo E mediated lipoproteins. In conclusion firstly, E4 mediated alteration through LDL or E receptors results in lower TG or higher $\beta$-lipoprotein levels and E2 shows reciprocal effects of E4, respectively. Second, E4 allele was more atherogenic than E2 allele because the higher levels of AI such as HDL$_3$/HDL$_2$ were criticized.

• Spatial Information Research
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• 제8권1호
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• pp.85-99
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• 2000

보호동물사에 대한 서식지 분포정보는 개발압력이 심한 우리나라에서는 서식지 관리에 있어 매우 중요하다. 본 연구는 GIS와 로지스틱 회귀분석을 이용하여 멧돼지의 서식지 적합성모형을 개발하여 서식지 분포도를 작성하고 본 연구의 결과를 토대로 현재 우리나라의 멸종위기종과 야생동물보호종들의 서식지 관리를 위한 기초를 마련하고자한다. 서식지 모형을 구현하기 위한 연구내용 및 방법은 다음과 같다. 첫째, 멧돼지의 서식지 특성을 파악하기 위하여 GIS 자료를 구축하였다. 멧돼지의 위치파악을 위해 원격무선측정기법과 GPS를 이용하였다 둘째, 멧돼지의 서식지 이용과 유용성에 영향을 미치는 환경인자를 파악하기위해 원격무선측정기법과 GPS를 이용하였다. 둘째, 멧돼지의 서식지 이용과 유용성에 영향을 미치는 환경인자를 파악하기 위해 χ²검정(Chi-square test)을 실시하였다. 마지막으로, 최적 서식지의 분포를 예측하기위한 서식지 적합성모형 개발을 위해 로지스틱 회귀분석을 이용하였다. 본 연구의 결과는 다음과 같다. 첫째, 멧돼지의 서식지 이용특성 분석의 결과, 성별 그리고 활동유형별에서는 뚜렷한 차이를 볼 수 없으나, 계절별 그리고 서식지 유형별에서는 서식지 이용특성의 차이가 뚜렷한 것을 볼 수있었다. 둘째, 서식지 유용성 분석의 결과 멧돼지의 서식환경에 영향을 미치는 자연적인 환경요인으로 표고, 향, 임상 그리고 영급이 유의성이 있는 인자로 나타났다. 반면에, 경사, 능선/계곡 , 물 그리고 일사량의 경우 통계적 유의성이 적어 전반적으로 서식지를 결정하는 환경인자라고 볼 수 없었다. 마지막으로, 개발된 서식지 적합성모형의 결과 예측확률 0.5를 기준으로 전제서식지는 75.00%, 커버서식지는 84.26% 의 높은 분류정확도를 나타내었다. 모형검증의 결과 대상지 내부의 경우 전체서식지가 75.00%로 나타나 본 모형이 신뢰성이 있는 것으로 판단되었다.

• 유통과학연구
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• 제14권3호
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• pp.73-83
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• 2016

Purpose - The parcel delivery service(courier) industry all over the world has been expanding its market so far, but its growth has been declining in recent years. In this situation, most parcel delivery companies are having trouble with managing themselves because of the pressure from the customer to increase service level and decrease the rate. The purpose of this study is to provide ways to improve competitive advantages of the parcel delivery service industry by evaluating the multi-period operating efficiency of Korea, Japan and global service providers. Research design, data, and methodology - The data for the period of 2011 to 2014 were collected from the annual reports published by parcel delivery companies. In this study, we analyze the marketability (revenue), profitability (operating profits), and management conditions (net profits) of parcel service companies by combining information on human resources (number of employees) and material resources (total assets and equity). Therefore, the number of employees, total assets, and equity are selected as input variables, and revenue, operating profits, and net profits as the output variables. In this study, DEA (Data Envelopment Analysis) is used to measure the comparative efficiency and MPI (Malmquist Productivity Index) is used to analyze the trend of change of the efficiency for a multi-year period. Results - The operational efficiency scores of medium-sized parcel delivery companies in Korea are higher than other larger competitors such as Korean, Japan and Global larger companies. As of 2014, Logen(1.878) was found to be the most efficient parcel delivery enterprise, followed by KGB (1.224), and Kyoungdong(1.002). Otherwise, Hanjin(0.235), CJ(0.262), Hyundai Logistics(0.657), DHL(0.611), UPS(0.766), FedEx(0.498), TNT(0.350), Yamato(0.762) and Sagawa(0.520), larger sized companies, were done inefficiently. The productivity of parcel delivery companies is influenced by endogenous factors as well as exogenous ones such as changes in business environment and technological advances. Conclusions - Korean medium-sized companies have relatively high efficiency scores in operation. That is why they still survive the competitive market in Korea where market restructuring on the industry has been expected to be conducted for many years. The reason why medium-sized couriers had higher efficient scores than larger couriers is that most of couriers spend more operating expenses versus unit price of delivery which is the amount of money that is needed in order to send a package by parcel service. So the delivery unit price must be taken into account by all the expenses associated with the cost of fuel, labor and maintenance expenses for facilities, etc. therefore, the unit price must be increased to strengthen business competitive power. In order for the industry to have more competitive advantage, the companies need to make profits by increasing demand volume and raising the delivery rate to provide high-quality delivery service to customers. And both endogenous and exogenous change must take precedence in order to strengthen their competitiveness.

• 폴리머
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• 제24권1호
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• pp.97-104
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• 2000

산화처리 된 평직형태의 탄소섬유와 resole 형태의 페놀수지를 7:3 중량비로 혼합하여 성형공정에 따라 탄소섬유/페놀수지 복합재료를 제조하였으며, 이를 다시 불활성 분위기에서의 탄화(100$0^{\circ}C$) 및 $CO_2$ 분위기에서 활성화(700, 800,, 900 및 100$0^{\circ}C$)시켜 PAN계 활성탄소섬유/페놀수지 복합재료를 제조하였다. 본 연구에서는, 이렇게 제조된 복합재료에 활성화 온도가 미치는 영향을 중화 적정법에 따른 pH, 표면 산도 및 표면 염기도 등의 표면성질과 BET 방법에 따른 비표면적, 기공구조 등의 흡착특성을 측정하여 고찰하였다. 또한, ASTM에 따라 시편에 걸리는 압력 손실을 측정하였다. 결과적으로, 활성화 온도는 그 표면 성질의 변화에 영향을 주어, 90$0^{\circ}C$ 이상의 온도에서 시료의 표면은 점차 염기성이 커지는 것을 확인할 수 있었다. 또한, 비표면적, 총 기공 부피 및 기공 크기 분포도 등의 발달은 활성화 온도의 증가에 따라 점차 증가함을 쉽게 확인할 수 있으며, 그 중 활성화 온도가 90$0^{\circ}C$인 경우 가장 발달한 것으로 나타났다. 마찬가지로, 활성화 온도의 증가에 따라 시편 양 단면에 걸리는 압력손실은 점차 감소하였으며, 이것은 열처리 온도에 의한 활성탄소섬유 복합재료의 질량손실에 의한 것으로 사료된다.