• The Korean Journal of Pain
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• 제32권1호
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• pp.12-21
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• 2019

Spinal cord contusion injury is one of the most serious nervous system disorders, characterized by high morbidity and disability. To mimic spinal cord contusion in humans, various animal models of spinal contusion injury have been developed. These models have been developed in rats, mice, and monkeys. However, most of these models are developed using rats. Two types of animal models, i.e. bilateral contusion injury and unilateral contusion injury models, are developed using either a weight drop method or impactor method. In the weight drop method, a specific weight or a rod, having a specific weight and diameter, is dropped from a specific height on to the exposed spinal cord. Low intensity injury is produced by dropping a 5 g weight from a height of 8 cm, moderate injury by dropping 10 g weight from a height of 12.5-25 mm, and high intensity injury by dropping a 25 g weight from a height of 50 mm. In the impactor method, injury is produced through an impactor by delivering a specific force to the exposed spinal cord area. Mild injury is produced by delivering $100{\pm}5kdyn$ of force, moderate injury by delivering $200{\pm}10kdyn$ of force, and severe injury by delivering $300{\pm}10kdyn$ of force. The contusion injury produces a significant development of locomotor dysfunction, which is generally evident from the $0-14^{th}$ day of surgery and is at its peak after the $28-56^{th}$ day. The present review discusses different animal models of spinal contusion injury.

• Geomechanics and Engineering
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• 제36권1호
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• pp.27-37
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• 2024

The roof-filling body system stability plays a key role in gob-side entry retained (GER). Taking the GER of the 1103 belt transportation roadway in Heilong Coal Mine as engineering background, stability analysis of roof-filling body system was conducted based on the cusp catastrophe theory. Theoretical results showed that the current design parameters of 1103 belt transportation roadway could ensure the roof-filling body system stable during the resistance-increasing support stage of the filling body and the stable support stage of the filling body. Moreover, a verified global numerical model in FLAC3D was established to analyze the failure characteristics including surrounding rock deformation, stress distribution, and plastic zone. Numerical simulation indicated that the width-height ratio of the filling body had a great influence on the stability of the roof-filling body system. When the width-height ratio was greater than 0.62, with the decrease of the width-height ratio, the peak stress of the filling body gradually decreased; when the width-height ratio was greater than 0.92, as the distance to the roadway increased, the roof stress increased and then decreased. The theoretical analysis and numerical simulation findings in this study provide a new research method to analyze the stability of the roof-filling body system in GER.

• 대한소아치과학회지
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• 제45권1호
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• pp.98-108
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• 2018

본 연구의 목적은 소아 및 청소년의 성장단계별(성장급증기 이전, 성장급증기, 성장급증기 이후) 골격성 II급 1류 및 2류 환자의 비인후 및 구강인후 부위인 상기도부의 기도 폭경을 평가하기 위함이다. 골격성 I급 청소년을 대조군으로 하였다. 전남대학교 치과병원 소아치과에 내원한 소아 및 청소년환자 159명(골격성 I급 70명, 골격성 II급 1류 51명, II급 2류 38명)을 대상으로 하였다. 측모두부 방사선사진과 수완부 방사선사진을 이용하여 성장단계별로 분류하였다(성장급증기 전, 성장급증기, 성장급증기 후). 상기도부의 해부학적 폭경을 측정하기 위해서 13개의 계측점, 5개의 계측각, 5개의 계측선, 3개의 비율을 측정하였다. 그 결과, 비인후 및 구강인후 부위의 전후방 폭경은 조사된 모든 그룹에서 성장과 함께 증가하였다. 부정교합에 따른 비인후 기도부위와 상부 구강인후 기도 부위 폭경의 통계적 차이를 밝히지는 못하였으나, 하부 구강인후 기도부의 전후방 폭경은 골격적 II급 부정교합군이 1급 부정교합군보다 더 좁게 나타났다.

• 유기물자원화
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• 제15권4호
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• pp.115-124
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• 2007

다량의 유기성 폐기물을 신속히 처리하기 위한 대용량의 반응조 개발이 이루어짐에 따라 대형 반응조 내부에서 재료물질 자체의 물리적 특성변화가 퇴비화에 미치는 영향을 파악하기 위한 연구가 시도되고 있다. 특히 좁은 공간에서 단위 면적당 처리량을 높일 수 있는 수직형 반응조에서는 재료가 갖는 자체적인 무게로 인한 침하 현상이 발생하여 퇴비화공정에 영향을 미치게 된다. 본 연구에서는 수직형 퇴비화 반응조 내에서의 수직 높이구간별로 재료물질의 온도, 수분함량, 용적밀도, 고형물함량, 침하거리 등의 물리적 성상 변화를 측정하여 수직형 반응조에서의 침하현상에 의한 효과를 파악하고자 하였다. 이를 위하여 수직형 퇴비화 반응조를 제작하여 계분과 톱밥을 혼합한 퇴비화 재료를 투입한 후 일정한 공기 유량을 주입하면서 퇴비화기간 동안의 반응조 높이별 물리적 성상 변화를 측정 하였다. 실험결과, 각 높이구간별로 최대온도 이후의 온도 재상승에 의한 변동폭은 교반횟수가 증가함에 따라 감소하고 있으며, 각 수직 높이 구간별로는 수직높이가 높아질수록 온도상승폭이 증가하고 있다. 수분함량 변화는 하층부에서의 증발수분이 상층구간으로 이동하게 됨으로써 반응조 높이가 높아질수록 수분함량이 높아지는 결과가 나타났다. 용적밀도는 수분함량 변화와 유사한 경향을 나타내었으며, 수분함량과 용적밀도와는 2차식($R^2=0.94$)의 관계를 보이고 있다. 각 높이구간에서의 고형물 함량은 수직높이가 높아질수록 감소하는 것으로 나타났다. 이와 같은 수직형 반응조에서의 높이구간별 물리적 성상변화는 퇴비화 재료물질의 침하현상에 기인한 것으로 나타났으며, 퇴비화 재료물질의 침하거리를 시간에 따른 1차식($R^2=0.91$)으로 나타내면 Ls(침하거리, cm)=$2.184{\times}T$(시간, day)와 같은 관계식을 얻을 수 있었다. 이러한 수직형 반응조내 재료물질의 침하현상은 자유공기공극(FAS)을 폐쇄시키고 공기투과성(air permeability)을 감소시켜 국부적으로 공기흐름을 저해하거나 혐기성 상태를 유발시키는 원인이 된다.

• Journal of Nutrition and Health
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• 제24권3호
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• pp.219-229
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• 1991

The longitudinal changes on human milk volume per day and lactational performance of 23 Korean lacto-ovo-vegetarians(primiparae=11, multiparae=12) from 0.5 to 5 months after parturition have been studied by test weighing method. The human milk volume per day tended to increase during lactation. The mean volume (SD, ml/day) at 0.5, 1, 2, 3, 4, 5 months were 502(102), 692(127), 697(100), 684( 125), 757(52), 703(70), respectively. The overall mean volume was 661$\pm$132ml/day. The peak milk volume during the lactation was observed at most lactating women at the 1st month. The distributions of the individual mean volume during the first 5 months of lactation were found over 750m1(8.7% ), 650-750ml(47.9% ), 550-650m1(2l.7% ), and 450-550ml(2l.7% ) The number of feeding per day was 8.1 ($\pm$1.0) at 0.5 months postpartum, which was consistently decreased. However, the mean volume per feeding was increased from 62($\pm$9.5)ml at 0.5 month to 112($\pm$13.3)ml at 5 months postpartum. The milk volume was correlated with the peak volume. and maternal age. but not with weight before delivery. maternal height and birth weight. No differences of milk volume and lactational performance between facto-ovo-vegetarian and nonvegetarian women were observed. This study suggests that the human milk volume cited in the recommended dietary allowances for Koreitns is over estimated.

• 한국공간구조학회논문집
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• 제20권2호
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• pp.69-76
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• 2020

Wind tunnel tests were conducted to analyze the wind fluctuating pressures on a circular closed and open dome roof with a low span rise. Two dome models with various geometric parameters (height/span ratios and open ratios) were used for fixed span rise ratio dome and wind pressure spectrum were analyzed. The applicability was examined in comparison with the spectral model proposed in the previous studies. The analysis results show that the wind pressure spectrum of open dome roof tends to increase power in the high frequency range and the second peak is found in the area different from the closed dome roof. In addition, according to the comparison analysis with the previous proposed spectral model, it was found that it is not applicable to the closed and open dome roofs with low rise ratio due to the different peak frequencies.

• The Korean Journal of Ecology
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• 제25권5호
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• pp.321-328
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• 2002

등산객에 의한 많은 간섭을 받아온 설악산 대청봉의 아고산생태계에서 훼손된 식생의 복원에 필요한 기초자료를 제공하기 위하여 인간에 의한 답압에 따른 입지인자와 식생의 변화를 파악하였다. 본 조사지역에서 인간에 의한 간섭은 경사도 10° 미만의 완만한 남사면 지역에서 두드러졌다. 인간의 간섭은 식생의 키. 식피율 및 종다양성을 감소시켰고, 식생의 종조성의 변화를 통하여 식생구조의 변화를 유발하였다. 또한 인간의 간섭은 파괴된 식생으로 인한 낙엽생산이 감소하고, 고산지대 특유의 바람에 의한 낙엽의 이동으로 인하여 낙엽층과 유기물층의 발달이 저해되었다. 이는 토양수분함량을 감소시키고, 토양침식작용이 활발해져 토심이 얕아지고 표토층이 유실되면서 자갈이 지표면에 노출된 입지환경으로 변화시켰다.

• International Journal of Ocean System Engineering
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• 제2권3호
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• pp.151-159
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• 2012

The characteristics of an impact load and pressure were experimentally investigated. Drop tests were carried out using a modified Wigley with CB = 0.56. The vertical force, pressures, and vertical accelerations were measured. A 6-component load cell was used to measure the forces, piezo-electric sensors were used to capture the impact pressure, and strain-gauge type accelerometers were used to measure the vertical accelerations. A 50-kHz sampling rate was applied to capture the peak values. The repeatability of the measured data was confirmed and the basic characteristics of the impact load and pressure such as the linearity to the falling height were observed for all of the measurements. A simple formula was derived to extract the physical impact load from the measured force based on a simple mass-sensor-mass diagram, which was validated by comparing impact forces with existing data using the mathematical model of Faltinsen and Chezhian (2005). The effects of the elasticity of the model and change in acceleration during the water entry were investigated. It is interesting to observe that the impact loads occurred and reached peak values at the same time duration after water entry for all drop heights.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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• pp.311-314
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• 2005

To evaluate the acute effects of fine particles on pulmonary function, a longitudinal study was conducted. This study was carried out for the schoolchildren(3rd and 4th grades) living in Inner-Mongolia, China. 113 Chinese children were asked to record their daily levels of peak expiratory flow rate(PEPR) using portable peak flow meter(mini-Wright) for 40 days and 3 time everyday(12 April 2004 to 21 May 2004). The atmospheric concentration of fine particles in study area was also determined everyday during same period. The relationship between dailypeak expiratory flow rate(PEFR) and fine particle levels was analyzed using a mixed linear regression models including gender, age, height, the presence of respiratory symptoms, and daily average relative humidity as extraneous variables. The analysis showed that the increase of fine particle concentrations was negatively associated with the variability in PEPR. The IQR(inter-quartile range) increments of $PM_{10}$ or $PM_{2.5}(66.0{\mu}g/m^3$ and $118.9{\mu}g/m^3$, respectively) were also shown to be related with 1.422L/min(95% Confidence intervals: 0.270 ${\sim}$ 2.574) and 1.214L1min(95% Cl: 0.010 ${\sim}$ 2.418) decline in PEFR.

• Wind and Structures
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• 제24권2호
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• pp.185-204
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• 2017

High-resolution wind measurements at 2.25 m in height were used to investigate the mean and turbulence properties of an extreme thunderstorm wind event in West Texas. These data were combined with single Doppler scans from the Texas Tech University Ka-band mobile Doppler radars systems (TTUKa) to provide meteorological context over the surface measurement stations for portions of the outflow. Several features characteristic of a severe wind event were noted in the radar data, including a bowing portion of the thunderstorm complex and a small circulation on the leading edge. These features were reflected in the surface wind time histories and provided natural separation between various regions of the outflow. These features also contributed to the peak 1-s gust at all measurement stations. The turbulence characteristics of each outflow region were also investigated and compared. Reduced values of running turbulence intensity and elevated values of longitudinal integral scales were noted during the period of peak wind speed. Larger scales of turbulence within the outflow were also suggested via spectral analysis.