• 농업과학연구
• /
• 제6권2호
• /
• pp.166-184
• /
• 1979

Dam에 저수(貯水)한 물이 흙수로(水路)에 의(依)해서 도수(導水)되는 과정(過程)에서 많은 손실(損失)을 보게 된다. 특(特)히 이들 용수로(用水路)가 사력층(砂礫層)과 같은 투수성지반(透水性地盤)을 통과(通過)할 때 용수로(用水路)의 누수방지(漏水防止)를 위(爲)해서 Lining을 실시(實施)하여 왔다. 이들 용수로(用水路)의 누수방지(漏水防止)를 위(爲)한 Lining 방법(方法)은 많은 연구(硏究)가 계속(繼續)되어 왔고 최근(最近)에는 plastic film 혹은 polyethylene film 등(等)으로 Lining 하는 방법(方法)이 고안(考案)되어 연구(硏究)하고 있다. 그러나 이들 재료(材料)는 강도(强度)가 약(弱)하여 파손(破損)될 위험성(危險性)이 있고 또 모래나 자갈 입자(粒子)와 접촉(接觸)하면 pin-hole이 생겨서 누수(漏水)하게 된다. 본(本)연구(硏究)에서는 이와 같은 흠점(欠點)을 보완(補完)하기 위(爲)하여 polypropylene mat에 vinyl을 coating해서 매설(埋設) Lining하는 방법(方法)을 시험(試驗)하였다. Polypropylene mat 매설(埋設) 혹은 노출(露出)에 따르는 내구성(耐久性)의 변화(變化), Asphalt 부착부(附着部)의 내구성(耐久性) 및 동해(凍害) 등(等)은 장기간(長期間)의 시험(試驗)이 필요(必要)하므로 아직도 미비(未備)된 점(點)이 있으나 본시험(本試驗)에서 얻은 결과(結果)를 요약(要約)하면 다음과 같다. 1. 수로(水路)의 저면(底面)과 양측사면(兩側斜面)의 연결부(連結部)는 곡선(曲線)으로 설치(設置)하는 것이 사면(斜面)의 안정도(安定度)가 크고 공사비(工事費)가 절약(節約)된다. 곡급부(曲級部)의 곡율변화(曲率變化)와 polypropylene mat의 감소량(減少量) 및 절토(切土)의 감소량(減少量)과의 관계(關係)를 사면(斜面)의 경사(傾斜)로 유도(誘導)해서 그림 7~그림 9에 표시(表示)하였다. 2. Polypropylene mat의 보호(保護)를 위(爲)해서 피복재료(被覆材料)를 덮어야 하고 이 두께는 수심(水深), 사면(斜面)의 안정(安定), 수로내((水路內) 침전물(沈澱物)의 제거작업(除去作業), 통행(通行), 비관개기(非灌漑期)의 back pressure 등(等)을 고려(考慮)해서 30cm 이상(以上)으로 함이 바람직하다. 3. 피복재료(被覆材料)는 사면침식(斜面侵蝕)을 방지(防止)하기 위(爲)해서 모래질(質)흙은 속에 넣고 표면(表面)은 조립질(粗粒質)의 자갈을 덮는 것이 수로사면(水路斜面)의 안정(安定)을 위(爲)해서도 좋을 것이다. 4. 용수로(用水路)의 사면안정검토(斜面安定檢討)는 수로저면(水路底面)의 수동부(受動部)를 고려(考慮)함이 타당(妥當)하고 사면안정(斜面安定), 허용유속(許容流速) 및 소유력(掃流力)을 고려(考慮)해서 1 : 2정도(程度)의 경사(傾斜)로 설치(設置)함이 바람직하다. 5. Earth Lining의 공사비(工事費)와 비재(比載)할 때 Vinyl로 coating 한 polypropylene mat의 Linging은 흙의 운반거리(運搬距離) 500m 일 때는 28%, 700m 일 때는 37%의 공사비(工事費)를 절약(節約)할 수 있다. 6. Vinyl로 coating 한 'polypropylene mat로 Lining 하면 거의 완벽(完壁)할 정도(程度)로 누수(漏水)를 방지(防止)할 수 있으나 Asphalt로 접합(接合)시켰을 때 polypropylene mat의 강도(强度)에 변화(變化)가 오는 것이 예상(豫想)되므로 경과시간(經過時間)에 따르는 강도변화(强度變化)는 계속(繼續)해서 연구(硏究)해야 할 것으로 생각된다.

• Journal of the Korean Wood Science and Technology
• /
• 제45권4호
• /
• pp.419-431
• /
• 2017

The forest slopes cause substantial local changes in soil properties and an increase in soil erosion after extreme rainstorms. The high soil erosion rates on forest slopes need the effective use of growing media to control the soil runoff. Therefore, we prepared six different lignocellulosic growing media such as peat, perlite, and wood meal as the base materials and carboxymethyl cellulose (CMC), glucomannan, starch, old corrugated containerboard, and computer printout as the additional materials for the prevention of simulated rainfall-induced runoff. The growing media containing old corrugated containerboard efficiently reduced the percentage of soil runoff; however, it could not completely cushion the influence of crust. The best results for plant growth, except in the leaf area, were also obtained with the growing media containing old corrugated containerboard, suggesting an interesting way of paper recycling and an economic benefit for plant or crop growth in forest slope.

• 한국해양공학회지
• /
• 제23권2호
• /
• pp.104-109
• /
• 2009

In the view of the importance of material reduction due to the jump in oil and steel prices, an optimized structural system for lifting lugs was developed. Such a system is needed hundreds of thousands of times a year. A direct design process was added to this developed optimized system to increase the design efficiency and provide a way of directly inserting a designer's decisions into the design system process. In order to verify the system efficiency and convenience, several new prototype lug shapes were suggested using the developed system. From these research results, it was found that the slope of the main plate of the lug structure has a tendency to move from about 45 degrees to about 60 degrees and the design weight was reduced from an initial value of about 32kgf to about $15{\sim}19kg_f$ after the redesign. Based on these initial research results, an efficient reduction in steel weight was expected considering the enormous consumption of lug structures per year. Additionally, a more detail structural analysis through local strength evaluations will be performed to verify the efficiency of the optimum structural design for a lug structure.

• 말소리와 음성과학
• /
• 제2권3호
• /
• pp.11-22
• /
• 2010

The present study attempts to investigate declination in Korean and its relevant aspects to the length of utterance, the clause boundary, and focus. More specifically, I examine the relation of declination with the length of utterance, the declination reset at the clause boundary, and the effect of focus on declination. Results showed that the length of utterance had no relation with the first and last pitch values of the utterance but that they were consistent regardless of the length of utterance. However, the declination slope changed to be relatively gentle from the fourth accentual phrase to the end of the whole intonational phrase. There was a reset of declination in such a way that the first pitch in the second phrase was always lower than that of the first phrase, but the first pitch in the third phrase was not always lower than that of the second phrase when the whole utterance was composed of three phrases. Finally, the pitch values of the focusing words decreased as their position went back in a sentence. One declination line was formed in the case of focused utterance, but in the case of an utterance that contained a clause boundary, a new declination line was formed at the start of each new clause. These findings can be applied to developing a Korean speech synthesizer that contains natural prosody; they can be also utilized for teaching Korean prosody.

• 천문학회보
• /
• 제38권2호
• /
• pp.78.1-78.1
• /
• 2013

The hierarchical model of galaxy formation predicts that galaxy halos contain merger relics in the form of long stellar stream. Thus, tidal substructure of stars around globular clusters, such as tidal tails, could be an essential evidence of the merging scenario in the formation of the Galaxy. From April 2010 to December 2012, we obtained $45^{\prime}{\times}45^{\prime}$ wide-field JHKs near-infrared photometric imaging data for about 20 globular clusters in the Milky Way, and examined the stellar density distribution around globular clusters. Here, we introduce the preliminary results of stellar spatial distributions and radial surface density profiles of four globular clusters. In order to minimize the field star contamination and identify the cluster's member candidates stars, we used a statistical filtering algorithm and gave weights on the CMDs of globular clusters. In two-dimensional stellar density maps, we could found tidal stripping structures for some globular clusters. The orientation of tidal substructure seems to associate with the effects of dynamical interactions with the Galaxy and cluster's orbit. Indeed, the radial surface density profile accurately describes this stripping structures as a break in the slope of profile. The observational results could give us further observational evidence of merging scenario of the formation of the Galaxy.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
• /
• pp.337-338
• /
• 2008

2008년 현재 우리나라는 10%의 인구가 60세 이상인 이른바 고령사회에 접어들었다. 노인 인구의 증가로 인해 노인이 여가생활 또는 일반생활을 보조하기 위한 보행 보조기에 대한 관심이 증가되고 있다. 대부분 동력이 없는 보행보조기를 사용하고 있으며 이러한 기구는 경사로 공간 또는 힘이 약한 노인들에게 취약성을 가지고 있다. 이에 동력형 보행보조로봇에 관심이 증가하고 있다. 동력형 보행보조로봇 역시 경사로에 있어서 편리성과 안전성을 높이기 위한 연구가 필요한 실정이다. 이에 본 논문에서는 보행보조로봇이 경사로에 진입 하였을 경우 기울어진 경사로의 정도를 인식하여 모터를 제어 한다. TILT 센서를 이용하여 기울이짐 정도를 측정 하였고, 또한 로봇의 전류 실시간으로 체크하여 로봇의 안전성을 향상 하였다. 제어 시스템 구성은 사용자의 보행의지를 파악하기위해 FSR 센서를 부착하여 조향장치로 사용하였으며, 경사로를 인식하기 위해 Liquid 타입의 TILT 센서를 사용하였으며, 모션 제어를 위해 DSP를 사용하였다. 본 제어 시스템을 보조보행로봇에 적용하였을 때, 보행보조로봇이 오르막 경사로에 진입시 기존보다 힘을 적게 사용하여 경사로를 진행하였으며, 경사로에서 브레이크 작동속도가 향상 되었다. 또한 내리막 경사로에서는 모터의 힘을 적게 사용하고 중력의 힘을 사용하여 이를 통해 전류의 소비량을 개선 하였다.

• 신재생에너지
• /
• 제7권2호
• /
• pp.43-50
• /
• 2011

The only practical way to measure wind resource at high-altitude over 100 m above ground for a feasibility study on a high-rise building integrated wind turbine might be ground-based remote sensing. The remote-sensing campaign was performed at a 145 m-building roof in Jamsil where is a center of metropolitan city Seoul. The campaign aimed uncertainty assessment of Leosphere WindCube LIDAR and Scintec MPAS SODAR through a mutual comparison. Compared with LIDAR, the data availability of SODAR was about 2/3 at 550 m altitude while both showed over 90% under 400 m, and it is shown that the data availability decrease may bring a distortion of statistical analysis. The wind speed measurement of SODAR was fitted to a slope of 0.92 and $R^2$ of 0.90 to the LIDAR measurement. The relative standard deviation of wind speed difference and standard deviation of wind direction difference were evaluated to be 30% and 20 degrees, respectively over the whole measurement heights.

• 한국제4기학회지
• /
• 제22권2호
• /
• pp.1-5
• /
• 2008

Some reverse fault lines pass through the alluvial fans and west hill slope of Bulguksa mountains including Mt. Toham in the directions of N-S and NW-SE. The study area is known as relatively unstable, because of active faults. Assuming the record of earthquake in the Samguksagi, the architects in the construction of the Bulguksa temple should have recognized the possibility of breakdown from the earthquakes and the need for an unique structure against at that time. Against earthquakes, Greavee technique, a stonework construction technique following woothe one and use of Chushouok (Dongtleouok or Chumchaouok) were applied for the construction of Bulguksa temple. By designing the foundation stone with hole, a structure is prevented from motiff Ction that pillarsakdcede from a foundation stone in spite of horizontal load of earthquake while woot construction isaktrong frame at earthquake. The Bulguksa-temple isausually evaluated to be a beautiful architecture from the appeaultces like the weight balltced structure with unique decoration. ampressive architectures are beautiful in balance and harmony coming from the important and specific rolls in its own way by each part of whole structure. This beauty comes from the science.

• The Korean Journal of Physiology
• /
• 제4권2호
• /
• pp.19-24
• /
• 1970

Since the discovery of the muscle spindle by Hassall (1831), an intensive studies of its anatomical and physiological characteristics had been undertaken. Recent morphological studies of Boyd (1962) demonstrated that the muscle spindles have two different intrafusal muscle fibers, nuclear bag and nuclear chain fiber, and these intrafusal fibers are under independent motor innervation by ${\gamma}_1$ and ${\gamma}_2$ motor neurone. Neurophysiological studies of Hunt and Kuffler (1951) showed regulatory effect of ${\gamma}$ motor neurone upon the excitability of the spindle afferents. Harvey and Mathews (1961) observed the dynamic and static characteristics of the two different spindle afferents, the primary and secondary ending. Furthermore, Mathews (1962) postulated the functional existance of two kind of ${\gamma}$ motor neurones, namely, the dynamic and static fusimotor fiber. Recent report of Kim and Partridge(1969) pointed out that the descending vestibular signals had increased the slope of the length-tension relationship in stretch reflex; Kim (1967) demonstrated that the descending vestibular impulses act upon the stretch reflex loop through the ${\gamma}$ motor pathway. These experimental evidences from the morphological and neurophysiological studies on the muscle spindles support the concept that the stretch reflex action of the skeletal muscle operates as a negative feedback control system. The author had discussed the way by which the f system participates in the control of stretch relfex feed back system. that was taken for a prototype of posture and movement.

• 국제물리치료학회지
• /
• 제2권2호
• /
• pp.324-328
• /
• 2011

The purpose of this study is to measure the effect of change in heel height on lower extremities activity of young women on high-heeled shoes that young women prefer from more kinetic and realistic perspective as this study changes the degree of slope on a treadmill. The study subjects are 15 young and healthy women who do not have any external injuries or problem with walking and understand the purpose of this study clearly. They wore three different height of heels(1cm, 7cm, 12cm) and walked on a treadmill at a constant speed of 3km/h. EMG value of four muscles (anterior tibial muscle, gastrocnemius muscle, straight muscle of thigh, and biceps muscle of thigh) were collected when walking and the change according to the height of heels were analyzed using one-way ANOVA. Multiple comparison analysis on anterior tibial muscle and heel height showed that the group with 12cm heel showed significantly high muscle activation compared to the groups with 1cm and 7cm heels. The result of this study can be used for various perspectives from inferring and mediating problems caused by wearing high heels on different ground slopes for a long time.