• 한국산림과학회지
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• 제101권2호
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• pp.317-323
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• 2012

본 연구는 우리나라 남부지방의 주요 조림수종인 편백(Chamaecyparis obtusa Sieb. et Zucc.) 노지묘와 용기묘의 생육단계별 생장특성을 탐구하고자 수행되었다. 1년생 노지묘의 간장생장은 용적이 31.2 mL와 300 mL 용기에서 생장한 용기묘 보다 좋았으며, 근원경 생장은 300 mL 용기의 용기묘가 가장 좋았다. 2년생 노지묘는 300 mL 용기의 용기묘보다 간장 및 근원경생장이 양호한 것으로 조사되었다. 건물생산량 비교에서, 1년생 지상부는 32 mL 용기묘가, 지하부 및 전체 건물생산량은 300 mL 용기묘가 가장 높았다. 2년생의 경우는 지상부는 노지묘가, 지하부는 용기묘의 건물생산량이 높은 것으로 나타났다. 뿌리전체길이, 뿌리투영단면적, 뿌리표면적, 뿌리평균직경, 뿌리부피 등 묘목의 뿌리형태 특성 비교에서, 1, 2년생 용기묘 모두 뿌리평균직경을 제외하고는 노지묘보다 더 높은 생장을 보였다. 본 실험의 결과를 종합해 볼 때, 편백 묘목생산과정에서 용기묘가 노지묘에 비해 상대적으로 뿌리발달이 뛰어난 묘목으로 생장한 것으로 판단된다.

• 아시안잔디학회지
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• 제10권3호
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• pp.263-270
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• 1996

This experiment was conducted to investigate the loss of various herbicides by means of vola-tility from the turfgrass field and the hare ground with the different soil moisture contents and temperatures. Different herbicides were applied at the rates of 375 g a.i. /l0a of pendimethalin,250 g a.i. /l0a of napropamide, and 96.4 g a.i. /l0a of dicamba with 200 \ulcorner/10a of spray volume in the turfgrass(Zoysia japonica cut off 5cm) grown in pots(265.8 $cm^2$) and bared soil. The pots were placed in the growth chamber with 10,000 lux of light intensity(12h per day) at 25 and 35˚C for 7days. Amberlite XAD polymeric resin(20/50 mesh) was used as sampling media for herbicide airborne residues. Air flow was maintained at 10 \ulcorner /min by vacuum pump regulated with a factory calibrated flow meter. Herbicide airborne residues were extracted from the XAD resin with 300 ml of 1:1 acetone and hexane. The extracts were concentrated by rotary evaporation at 35˚C and dissolved in 1 ml MeCN for HPLC analysis. The airborne losses of the herbicide applied in the turfgrass and bare soil increased as the temperature and soil moisture contents were increased, regardless of the kinds of herbicide. Higher airborne residues was observed in the turfgrass pots than the bare soil pots. Pendimethalin and dicamba with higher vapor pressure gave rise to the increased loss of airborne herbicides, showing that 6.26 and 6.4% of average airborne loss in pendimethalin and dicamba, respectively, compared to 0.56% in napropamide. The amount of airborne losses in turfgrass was highest at one day after application and then a declined trend was observed as the time was prolonged. Key words. Herbicides, Turfgrass field, Bare ground, Volatility.

• 한국환경복원기술학회지
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• 제13권2호
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• pp.24-41
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• 2010

Distributional characteristics of vascular plants and plants selection for revegetation in bare ground of lakeside was investigated in nine artificial lakes. The vascular plants were composed of 64 families, 194 genera, 268 species, 3 subspecies, 30 varieties, 3 forma, totaling 304 taxa. Dominant species of nine investigated areas were represented as Ambrosia trifida, Calystegia hederacea, Matricaria matricariodes, Xanthium italicum. Dominant species of three parts based on the location of artificial lakes were as follows:Ambrosia trifida, Bidens tripartita, Calystegia hederacea, Equisetum arvense, Setaria viridis, Spergula arvensis, Torilis japonica in northern part (Lake Paro and Soyang); Calystegia hederacea, Matricaria matricariodes, Rumex crispus, Xanthium italicum in middle part (Lake Chungju, Daecheong, Andong and Imha); and Ambrosia artemisiifolia, Bidens frondosa, Chenopodium glaucum, Miscanthus sinensis var. purpurascens, Persicaria pubescens, Setaria viridis in southern part(Lake Juam, Hapcheon and Jinyang). Among the 304 taxa, Korean endemic, endangered and rare plants were not investigated. The naturalized plants were 46 taxa, and life form was Th-$R_5-D_4$-e type. Above the results, Calystegia hederacea, Equisetum arvense, Xanthium italicum, Matricaria matricariodes, and Spergula arvensis were considered with proper species for revegetation in bare ground of lakeside in artificial lakes.

• 아시안잔디학회지
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• 제20권2호
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• pp.203-211
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• 2006

본 연구는 천연잔디, 인조잔디 및 맨땅 축구장이 축구 경기력에 미치는 영향을 구명하고자 하였다. 천연잔디 축구장은 한지형 잔디(켄터키 블루그래스 80%+퍼레니얼 라이그래스 20%)와 중엽형 한국잔디로 조성된 축구장이며, 인조잔디 축구장은 코니그린 $DV5000^{TM}$으로 조성하였고 맨땅 축구장은 마사토로 조성되었다. 축구 경기력 분석을 위한 볼 구름거리(m)와 수직 볼리바운드(m)는 2005년과 2006년 건국대학교 스포츠과학타운에서 조사하였다. 본 실험에 사용된 공은 한국축구협회(Korea Football Association)에서 공인된 Hummel Air Vision #1을 사용하였고 공기압은 1.0 1bs를 유지하였다. 볼 구름거리는 맨땅 축구장(13.6m) > 인조잔디 축구장(11.4m) > 한지형 잔디축구장(7.8m) > 한국잔디 축구장(4.7m) 순으로 길었다. 또한 볼 구름거리는 잔디의 사용빈도가 적을수록, 잔디의 직립정도가 강할수록, 잔디의 밀도가 높을수록 짧아지는 경향이었다. 수직 볼리바운드 역시 맨땅 축구장(1.0m) > 인조잔디 축구장(0.98m) > 한지형 잔디 축구장(0.68m) > 한국잔디축구장(0.4m) 순으로 높았다. 수직 볼 리바운드는 잔디의 사용빈도가 적을수록, 잔디의 직립정도가 강할수록, 잔디의 밀도가 높을수록 낮아지는 경향이었다. 표준관리가 되는 한지형 잔디 축구장은 조성연수에 따른 볼 구름거리와 수직 볼 리바운드에 미치는 영향이 적었다. 반면 표준 관리가 하지 않은 한국잔디 축구장은 오래 될수록 볼 구름거리는 길어졌고 수직 볼 리바운드 역시 높았다.

• 한국운동역학회지
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• 제21권1호
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• pp.9-16
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• 2011

The purpose of this study is to analyze the effects of both various shoe types and bare feet on ground reaction force while walking. Ten first-year female university students were selected. A force platform(Kistler, Germany) was used to measure ground reaction force. Six types of shoe were tested: flip flops, canvas shoes, running shoes, elevated forefoot walking shoes, elevated midfoot walking shoes, and five-toed shoes. The control group was barefooted. Only vertical passive/active ground reaction force variables were analyzed. The statistical analysis was carried out using the SAS 9.1.2 package, specifically ANOVA, and Tukey for the post hoc. The five-toed shoe had the highest maximum passive force value; while the running shoe had the lowest. The first active loading rate for running shoes was the highest; meanwhile, bare feet, the five-toed shoe, and the elevated fore foot walking shoe was the lowest. Although barefoot movement or movement in five toed shoes increases impact, it also allows for full movement of the foot. This in turn allows the foot arch to work properly, fully flexing along three arches(transverse, lateral, medial), facilitating braking force and initiating forward movement as the tendons, ligaments, and muscles of the arch flex back into shape. In contrast movement in padded shoes have a tendency to pound their feet into the ground. This pounding action can result in greater foot instability, which would account for the higher loading rates for the first active peak for padded shoes.

• 한국지반공학회논문집
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• 제38권3호
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• pp.17-26
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• 2022

국내의 지역난방을 위해 지중에 매설된 열수송관은 노후화로 인한 손상을 감지하기 위하여 지표면 온도변화에 기반한 안전관리 기준이 필요하다. 본 논문은 열수송관의 매설과 누수로 인한 지표면 온도 변화에 대하여 수치해석을 수행하였다. 열수송관이 매설된 지면과 주변지면의 온도차는 오전3시~오전8시에 가장 크게 나타났으며, 하절기 보다는 동절기에 온도차가 크게 발생하였다. 지하수위의 하강은 열수송관에 의한 지표면의 온도 증가를 크게 하고, 아스팔트 지면조건은 토사 지면조건에 비하여 지하수위 변화의 영향이 작게 나타났다. 열수송관의 누수가 없는 경우, 열수송관에 의한 지표면 온도 상승은 토사지반에서 3.0℃, 아스팔트 포장에서는 3.5℃이내로 나타났다. 토사 지면조건에서 열수송관의 누수에 의한 지면온도 변화는 하절기에는 완만하게, 동절기에는 급격하게 상승하였다. 아스팔트 포장조건은 토사 지면조건보다 누수에 의한 지표면의 온도 상승폭과 상승률이 작게 나타났다. 그리고 공급관의 양측 누수에 의하여 수송관 상부 지면과 주변지면의 온도차이가 10℃에 도달하는데 1~2일 정도 소요되었다.

• 한국운동역학회지
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• 제24권2호
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• pp.151-160
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• 2014

The purpose of this study was to investigate the GRF(ground reaction force) parameters according to the shoes's heel heights and ground landing distances during downward stairs on bus. Participants selected as subject were consisted of young and healthy women(n=9, mean age: $21.30{\pm}0.48$ yrs, mean height: $164.00{\pm}3.05cm$, mean body mass: $55.04{\pm}4.41kg$, mean BMI: $20.47{\pm}1.76kg/m^2$, mean foot length: $238.00{\pm}5.37mm$). They were divided into 2-types of shoe's heel heights(0 cm/bare foot, 9 cm) and also were divides into downward stairs with 3 types of landing distance(20 cm, 35 cm, 50 cm). A one force-plate was used to collect the GRF(AMTI, USA) data from the sampling rate of 1000 Hz. The GRF parameters analyzed were consisted of the medial-lateral GRF, anterior-posterior GRF, vertical GRF, loading rate, Center of Pressure(${\Delta}COPx$, ${\Delta}COPy$, COP area) and Dynamic Postural Stability Index(MLSI, APSI, VSI, DPSI) during downward stairs on bus. Medial-lateral GRF and vertical GRF didn't show significant differences statistically according to the shoe's heel heights and landing distance, but 9 cm shoes heel showed higher vertical GRF than that of 0 cm bare foot in landing distance of 50 cm. Also anterior-posterior GRF didn't show significant difference statistically according to the shoe's heel heights, but landing distance of 20 cm showed higher than that of landing distances of 35 cm and 50 cm in anterior-posterior GRF. Loading rate didn't show significant difference statistically according to the landing distance, but 9 cm shoe's heel showed higher than that of 0 cm bare foot during downward stairs. The ${\Delta}COPy$ and COP area didn't show significant differences statistically according to the shoe's heel heights and landing distance, but 0 cm bare foot showed higher than that of 9 cm shoe's heel in ${\Delta}COPx$. Dynamic Postural Stability Index(MLSI, APSI, VSI, DPSI) didn't show significant differences statistically according to the landing distance, but 9 cm shoe's heel showed decreased value than that of 0 cm bare foot in dynamics balance. Considering the above, parameters of GRF showed different characteristics according to the shoe's heel heights and ground landing distances during downward stairs on bus.

• 한국환경과학회지
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• 제12권7호
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• pp.705-713
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• 2003

In mid-August 2002, under clear summer pressure patterns, we carried out an intensive meteorological observation to examine the warming effects due to artificial constructions in a large housing complex. We set an automatic weather system(AWS) at two places in a bare soil surface within a limited development district and an asphalt surface within a large apartment residence area, respectively. As a result of observation, it became clear that the difference of the surface air(ground) temperature between the bare soil surface and its peripheral asphalt area reached about 4$^{\circ}C$(13$^{\circ}C$) at the maximum from diurnal variation of surface temperatures on AWS data. Through the heat balance analysis using measurement data, it became clear that the thermal conditions at two places are dependent on the properties of surface material. The latent heat flux over the bare soil surface reached to about 300 W/㎡, which is more than a half of net radiation during the daytime. On the other hand, it was nearly zero over the asphalt surface. Hence, the sensible heat flux over the asphalt surface was far more than that of the bare soil surface. The sensible heat flux over the asphalt surface showed about 20∼30 W/㎡ during the night. It was released from asphalt surface which have far more heat capacity than that of bare soil surface.

• 마이크로전자및패키징학회지
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• 제28권3호
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• pp.1-7
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• 2021

본 논문에서는 Bare-die Chip 형태의 Drive amplifier를 Ajinomoto Build-up Film (ABF)와 FR-4로 구성된 PCB에 내장함으로써 28 GHz 대역 모듈에서 적용될 수 있는 내장형 능동소자 모듈을 구현하였다. 내장형 모듈에 사용된 유전체 ABF는 유전율 3.2, 유전손실 0.016의 특성을 가지고 있으며, Cavity가 형성되어 Drive amplifier가 내장되는 FR4는 유전율 3.5, 유전손실 0.02의 특성을 가진다. 제안된 내장형 Drive amplifier는 총 2가지 구조로 공정하였으며 측정을 통해 각각의 S-Parameter특성을 확인하였다. 공정을 진행한 2가지 구조는 Bare-die Chip의 패드가 위를 향하는 Face-up 내장 구조와 Bare-die Chip의 패드가 아래를 향하는 Face-down내장 구조이다. 구현한 내장형 모듈은 Taconic 사의 TLY-5A(유전율 2.17, 유전손실 0.0002)를 이용한 테스트 보드에 실장 하여 측정을 진행하였다. Face-down 구조로 내장한 모듈은 Face-up 구조에 비해 Bare-die chip의 RF signal패드에서부터 형성된 패턴까지의 배선 길이가 짧아 이득 성능이 좋을 것이라 예상하였지만, Bare-die chip에 위치한 Ground가 Through via를 통해 접지되는 만큼 Drive amplifier에 Ground가 확보되지 않아 발진이 발생한다는 것을 확인하였다. 반면 Bare-die chip의 G round가 부착되는 PCB의 패턴에 직접적으로 접지되는 Face-up 구조는 25 GHz에서부터 30 GHz까지 약 10 dB 이상의 안정적인 이득 특성을 냈으며 목표주파수 대역인 28 GHz에서의 이득은 12.32 dB이다. Face-up 구조로 내장한 모듈의 출력 특성은 신호 발생기와 신호분석기를 사용하여 측정하였다. 신호 발생기의 입력전력(P_in)을 -10 dBm에서 20 dBm까지 인가하여 측정하였을 때, 구현한 내장형 모듈의 이득압축점(P_1dB)는 20.38 dB으로 특성을 확인할 수 있었다. 측정을 통해 본 논문에서 사용한 Drive amplifier와 같은 Bare-die chip을 PCB에 내장할 때 Ground 접지 방식에 따라 발진이 개선된다는 것을 검증하였으며, 이를 통해 Chip Face-up 구조로 Drive amplifier를 내장한 모듈은 밀리미터파 대역의 통신 모듈에 충분히 적용될 수 있을 것이라고 판단된다.

• Earthquakes and Structures
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• 제16권5호
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• pp.611-623
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• 2019

A set of mid-rise bare and uniformly infilled reinforced-concrete frame buildings are analyzed for two different seismic intensities of ground-motions (i.e., 'Design Basis Earthquake' and 'Maximum Considered Earthquake') to study their floor response. The crucial parameters affecting seismic design force for acceleration-sensitive non-structural components are studied and compared with the guidelines of the European and the United States standards, and also with the recently developed NIST provisions. It is observed that the provisions of both the European and the United States standards do not account for the effects of the period of vibration of the supporting structure and seismic intensity of ground-motions and thereby provides conservative estimates of the in-structure amplification. In case of bare frames, the herein derived component amplification factors for both the design basis earthquake and the maximum considered earthquake exceeds with their recommended values in the European and the United States standards for non-structural components having periods in vicinity of the higher modes of vibration, whereas, in case of infilled frames, component amplification factors exceeds with their recommended value in the European standard for non-structural components having periods in vicinity of the fundamental mode of vibration, and only for the design basis earthquake. As a consequence of these observations, as well as capping on the design force (in case of United states standard and NIST provisions), in case of the design basis earthquake, the combined amplification factor is underestimated for non-structural components having periods in vicinity of the higher modes of vibration of bare frames, and also for non-structural components having periods in vicinity of the fundamental mode of vibration of infilled frames. At the maximum considered earthquake demand, excepting non-structural components having periods in vicinity of the higher modes of vibration of bare frames, all provisions generally provide conservative estimates of the design floor accelerations.