• Title/Summary/Keyword: circle model

검색결과 295건 처리시간 0.026초

유연생산 시스템 구축을 위한 공작물 자동교환 유닛의 수평 이송 기구 설계에 관한 연구(파트 2) (A Study on the Design of Horizontal Traverse Units in an Automatic Object Changer Unit to Establish a Flexible Production System (Part 2))

  • 박후명;성재경;이용중;하만경
    • 한국기계가공학회지
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    • 제7권2호
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    • pp.52-59
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    • 2008
  • The objective of this study is to develop an automatic object changer unit to improve processing problems existed in the conventional horizontal machining center. To achieve this goal, this study designed a horizontal transfer as the second project continued to the first project that designed a upward and downward traverse unit. A horizontal traverse unit shows a symmetric structure and consists of frame, which consists of four unit tools, motor and reducer, which are fixed at a frame, operation unit with pinions, first traverse unit, and second traverse unit. Constraint conditions based on the operation mechanism with these elements were configured and obtained following results after modeling a model for a traverse motor. In the kinematic expression of sliding motion with one degree of freedom, the sliding motion is constrained. Also, the rack 3 installed at a frame is used to configure possible kinematic constraint conditions of the rack 2 according to the rolling motion of the pinion 2 in the first traverse unit. In addition, the moment of inertia that is a type of kinetic energy in a converted horizontal traverse unit in the side of the reducer can be applied to introduce the moment of inertia of a converted horizontal traverse unit in the side of the reducer by using the sum of kinetic energy in the rack and pinion, which is a part of the horizontal traverse unit. Also, the equation of motion of the converted upward and downward traverse unit in the side of the motor using the equation of motion of the motor. Furthermore, the horizontal traverse unit predetermines the mass of the first and second traverse unit and applied load including the radius and reduction ratio of the pitch circle in the pinion 1 and applied load to the rack 2. Then, a proper motor can be determined using several parameters in the upward and downward traverse unit in order to verify such predetermined specifications. In future studies later this study, a simulation that verifies the results of the previous two stages of studies using a finite element method.

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일 지역 대학생의 피로와 건강증진 생활양식과의 관계분석 (The correlation analysis between fatigue and health promoting life style among a rural college students)

  • 장희정
    • 기본간호학회지
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    • 제6권3호
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    • pp.477-492
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    • 1999
  • The disease patterns among the Korean was shifted from acute and infectious diseases to chronic diseases. According to the these disease patterns trends, people have concerned about the health promotion and health behaviors. Pender's(1996) revised health promotion model(HPM) is consist of three categories; Individual characteristics and experiences, Behavior-specific cognitions and affect, behavioral outcome. Of these categories, individual characteristics and experiences, this category of variables is considered to be of biological, psychological and socio-cultural personal factors, especially, individual fatigue. Futhermore. these variables constitute a critical core for nursing intervention, as they are subject to modification through nursing actions. But there is no few the research of the relationship between the fatigue and health promotion. Therefore, the purpose of this study is to investigate the correlation between the fatigue and health promoting life style among a rural college students. Additionally, this descriptive correlational study identified the relation of demographic factors and fatigue, health promoting life style. From June 20 to 26, 1998, a convenience sample of 270 college students completed the questionnaire of the fatigue and health promoting life style profile which were developed by the Yoshitake(1978) and Walker, et al.(1987), respectively. The descriptive correlational statistics, mean, t-test, ANONA, Pearson correlation coefficient were used to analyze the data gathered with SAS pc+ program. The results were as it follows: 1. The average fatigue score of the subjects was $64.93{\pm}12.89$. Fatigue scores by subcategory were physical symptoms($23.5{\pm}4.87$). psychological symptoms($22.11{\pm}4.66$) and neuro-sensory symptoms($19.32{\pm}5.14$). With the respect to the demographic characteristics of the subjects, there were statistically significant differences between the demographic factors and fatigue, especially, sex(t==3.69 p<0.01), major(t=-2.89 p<0.01). the experience of family illness(t=2.76 p<0.01). 2. The average health promoting life style item score of the subjects was $2.33{\pm}0.33$. In the subcategories, the highest degree of performance was self-actualization(2.94), following interpersonal support(2.81). stress management(2.33), exercise(2.20), nutrition(2.10), and the lowest degree was health responsibility(1.73). There were the significant differences on the learning of health education(t=2.00 p<0.01). religion(F=3.01, p<0.05), circle activity(t=2.07, p<0.05), nutrition control(t=5.25, p<0.01) of demographical factors with the health promoting life style. 3. The correlation between the fatigue and health promoting life style made statistically no significance(r=-0.09731, p>0.05). But there was negative significant relationship between health promoting life style and psychological symptom as a fatigue subcategory(r=-0.15721, p<0.05). The self-actualization showed negative significant correlation with all fatigue subcategory. The health responsibility showed significant relationship with total fatigue(r=0.13050. p<0.05). For further research, it suggests to replicate the correlational and causal study between the fatigue and the health promoting life style using the another fatigue scale which is able to measure the subjective and objective fatigue degree. And it needs to develop the nursing intervention program for maintaining and promoting the health behavior as well as for decreasing the college students's fatigue.

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압축 및 인발하중을 받는 그물식 뿌리말뚝의 최적 타설경사각 (An Optimum Slanting Angle in Reticulated Root Piles Installation under Compressive and Uplift Loads)

  • 이승현;김명보
    • 한국지반공학회지:지반
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    • 제12권2호
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    • pp.71-84
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    • 1996
  • 본 연구에서는 여러가지의 타설경사각을 갖는 모형 그물식 뿌리말뚝을 제작하여 모형토조에 설치하고 레이닝(raining)방법으로 지반을 조성한 다음 압축시험 및 인발시험을 하여 그물식 뿌리말뚝의 타설경사각과 하중지지력 사이의 관계를 비교분석 하였다. 모형말뚝은 0$^{\circ}$, 5$^{\circ}$, $10^{\circ}$, 15$^{\circ}$, 20$^{\circ}$, 그리고 25$^{\circ}$의 타설경사각을 갖는 직경 Sulm의 강봉에 모래를 입힌 것으로 직경이 6.5muL 길이가 300mm가 되도록 하였다. 모형 뿌리말뚝의 배치는 동일한 타설경사각을 갖는 8개의 모형 말뚝을 4개씩 2개의 크고 작은 동심원에 접하도록 하였다. 그리고 모형 원형 얕은 기초를 제작하여 압축시험을 수행한 다음 지지력을 구하여 뿌리말뚝의 지지력과 비교하였다. 압축시험 및 인발시험 결과를 회귀분석하면 하중지지능력이 최대가 되는 타설경사각은 대략 12$^{\circ}$~13$^{\circ}$사이이다. 최적 타설경사각에서의 뿌리말뚝의 압축지지력은 원형 얕은기초의 지지력과 비교하면 약 2.0배이고, 연직으로 타설된 뿌리말뚝의 경우와 비교하면 13%의 지지력 증대효과가 있다. 그리고 최적타설경사각에서의 뿌리말뚝의 인발저항력은 연직으로 타설된 뿌리말뚝의 경우 에 비해 21%의 인발저항력 증대효과가 있다. 압축시험으로부터 얻은 하중-침하량곡선은 타설 경사각이 없는 경우에 전반전단파괴 형태를 나타내며,타설경사각이 5$^{\circ}$, $10^{\circ}$인 경우, 하중은 극한 지지력에 도달한 후 일정한 값을 유지하는 양상을 보인다. 타설경사각이 15$^{\circ}$, 20$^{\circ}$, 25$^{\circ}$로 증가하면서 하중은 극한지지력에 도달한 후에도 계속 증가하는 경향이 있다. 따라서, 타설경사각이 있는 경우의 뿌리말뚝은 압축지지력을 초과하여 하중을 받더라도 급격한 파괴에 이르지 않고 점차로 변위가 증가하는 연성 (ductile)거동을 보일 것으로 예상된다.

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바이로이드-가장 작은 식물병원체 (Viroid-the Smallest Plant Pathogen)

  • 이재열
    • 한국식물병리학회지
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    • 제1권3호
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    • pp.199-206
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    • 1985
  • 바이로이드(viroid)는 그의 완전한 분자구조가 처음으로 밝혀진 식물병원체이며, coat-protein이 제거된 viral-RNA가 아닌 바이로이드로서의 독립적인 특성과 병원성을 가진 작은 크기의 병원체임이 밝혀짐으로써 미생물의 영역을 한 단계 넓혀서 생각하도록 하였다. 일반적으로 생각되는 미생물 즉 곰팡이, 세균, 마이코플라스마, 바이러스들이 동물과 식물 및 인체에 병원체로서 작용하는데 바이로이드는 현재까지 고등식물에서만 발견되는 병원체이다. 다라서 바이로이드가 동물 및 인체에서 아직까지 밝혀지지 않고 있는 병의 병원체일 가능성이 있으므로 이에 대한 연구가 계속되고 있다. 바이로이드는 작은 크기임에도 독자적인 자기증식을 하는 능력과 생존을 유지하는 특성이 있기 때문에 이들의 분자구조 및 생물적 특성을 연구하는데 좋은 자료가 되며, 최근에 급속한 진전을 보이고 있는 분자생물학 및 유전공학적인 방법과 기술을 이용하여 Viroid의 여러 가지 성질과 생물학적인 위치에 대한 연구가 활발히 진행되고 있다. 앞으로 연구가 계속되어 Viroid의 증식과 병원성에 대한 문제가 해결된다면, 바이로이드병의 예방이나 치료법이 확립된 것이며 또한 목적하는 유전자를 운반하는 Vector로 개발하여 생물공학 분야에 적극적으로 활용할 수 있을 것이다.

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절수시 Mongolian gerbil (Meriones unguiculatus) 콩팥의 Aquaporin 2, Aquaporin 4 발현변화 (Upregulation of aquaporin 2 and aquaporin 4 in the water-deprived mongolian gerbil (Meriones unguiculatus) kidney)

  • 송지현;권진석;김용환;박용덕;한기환;류시윤;정주영
    • 대한수의학회지
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    • 제47권4호
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    • pp.363-370
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    • 2007
  • Mongolian gerbil (Meriones unguiculatus) has been as an model animal for studing the neurological disease such as stroke and epilepsy because of the congenital incompleteries in Willis circle, as well as the investigation of water metabolism because of the long time-survival in the condition of water-deprived desert condition, compared with other species animal. Aquaporin 2 (AQP2) expressed at the surface of principal cells in collecting duct results from an equilibrium between the AQP2 in intracellular vesicles and the AQP2 on the plasma membrane. Aquaporin 4 (AQP4), which is expressed in cell in a wide range of organ, is also present in the collecting duct principal cells where this is abundant in the basolateral plasma membranes and represent potential exit pathways from the cell for water entering via AQP2. In this research, we divide 3 groups of which each group include the 5 animals. In the study of 7 or 14 days water restricted condition, we investigated the AQP2 and AQP4 by using a quantitative immunohistochemistry in the kidney. The results obtained in this study were summarized as followings. AQP2 is abundant in the apical plasma membrane and apical vesicles in the collecting duct principal cell and at rare abundance in connecting tubules. In the water-deprived Mongolian gerbil kidney, expression of AQP2 was continuosly increased in the cortical collecting duct and inner medullary collecting duct. This increase was both the apical region and cytoplasm. AQP4 is mainly expressed in the inner medulla, although some expression is also noted in the more proximal segment. In the water-deprived Mongolian gerbil kidney, AQP4 was also increased in the inner medullary collecting duct. Immunoactivity was increased in entire inner medullary collecting duct and newly detected in cytoplasm of principal cell. These findings suggest that increased levels of AQP2 and AQP4 in the cortical and inner medulalry collecting duct may play a important role for maintain fluid balance in the water-deprived kidney.

절수에 의한 mongolian gerbil 종뇌 및 간뇌에서 dopamine성 면역반응세포의 분포변화 (The change of dopaminergic immunoreactive cells in telencephalon and diencephalon of mongolian gerbil by water deprivation)

  • 송치원;이경열;박일권;정주영;권효정;이철호;현병화;이근좌;송운재;정영길;이강이;김무강
    • 대한수의학회지
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    • 제40권1호
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    • pp.1-16
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    • 2000
  • Nowadays, mongolian gerbil is notably utilized for the research of brain and water deprivation because of a congenital incomplete willis circle structure in the brain, audiogenic seizure in low noise, and special cholesterol metabolism without water absorption for a long time. In this study, we are intend to identify the morphological changes of the catecholaminergic neuron of brain according to the time lapse in the condition of long term water deprivation. 55 mongolian gerbil were divided 10 groups(control, 1, 2, 3, 4, 5, 10, 15, 20, 42th day water deprivation group), of which each group include 5 mongolian gerbils and 5 normal mongolian gerbils in control group were also used for brain atlas as a control. The brains were observed by the immunohistochemical stain using the TH, DBH and PMNT antibody. The results were as followings; 1. The nerve fibers of the TH-immunoreactive neuron were observed only in the and corpus striatum of the telencephalon. 2. Intensity of the immunostain of the nerve fiber in the cerebral cortex and corpus striatum was decreased gradually day by day after water deprivation. 3. The TH-immunoreactive nerve cells were observed in the paraventricular and periventricular nucleus of the 3rd ventricular in the hypothalamus of mongolian gerbil but the number of nerve cells were decreased from the first day of the water deprivation to the 10th day and increased until the 20th day, after than redecreased from the 20th day by the continuous water deprivation. The number of nerve fibers in this area were increased in the first day, but decreased from the 2nd day of water deprivation. The shape and density of the dopamine secreting cells in the brain of mongolian gerbil by the immunoreactive stain were changed in the continuous water deprivation. In this results, we can conclude that dopamine concerned in the water metabolism of mongolian gerbil, and mongolian gerbil could be used as an animal model for the research of water deprivation.

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제주도 초지피복 기생화산("오름")의 방위별 일 최고기온 분포 (Azimuthal Distribution of Daily Maximum Temperatures Observed at Sideslopes of a Grass-covered Inactive Parasitic Volcano ("Ohreum") in Jeju Island)

  • 서희철;전승종;윤진일
    • 한국농림기상학회지
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    • 제10권1호
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    • pp.25-31
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    • 2008
  • 초지피복 조건에서 사면의 일사수광량 차이가 일 최고기온에 미치는 영향을 파악하기 위해 2007년 하지부터 동지까지 밑면지름 570m, 높이 90m인 원추형 기생화산 "높은오름"의 측면 경사 8 지점에서 일 최고기온을 측정하였다. 8개 지점 평균값을 기준온도로하여 각 지점의 기온편차를 구해 비교한 결과 기온편차는 하지로부터 동지로 갈수록 커지는 경향이었고, 관측기간 평균은 남향사면에서 $1.0^{\circ}C$, 북향사면에서 $-0.8^{\circ}C$로서 그 차이가 평균 $1.8^{\circ}C$에 달했다. 기온편차의 월별 평균은 11월에 가장 크며 남향사면에서 $2.1^{\circ}C$, 북향사면에서 $-1.3^{\circ}C$였다. 일별 기온편차의 최대값은 남향사면에서 $3.8^{\circ}C$, 북향사면에서 $-2.7^{\circ}C$에 달했는데, 이러한 기온편차 변이는 일사수광량 편차에 근거한 지형특성지수와 높은 상관을 보여 복잡지형의 일 최고기온 추정모형 개발에 활용될 수 있을 것으로 기대된다.

Algebraic Analysis for Partitioning Root and Stem Lodging in Rice Plant

  • Chang, Jae-Ki;Yeo, Un-Sang;Lee, Jeom-Sig;Oh, Byong-Geun;Kim, Jeong-Il;Yang, Sae-Jun;Ku, Yeon-Chung;Kim, Ho-Yeong;Sohn, Jae-Keun
    • 한국작물학회지
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    • 제51권6호
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    • pp.539-543
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    • 2006
  • Lodging is classified as root lodging caused by the loss of supporting force in the root, bending caused by the deformation of the stem and breaking where the stem breaks down as loads exceeding critical elasticity were applied. This research excluded breaking which is not in a state of equilibrium and tried to partition the level of lodging using an algebraic model in root lodging and stem lodging, or bending. When a vertical load was applied, the deformation of the stem of rice plant showed the form of a quadratic equation. The trace of the panicle neck in the process of lodging was an ellipse-shape. When loading was pure root lodging, the trace of the panicle neck became a circle of which culm length is the radius. When it was a pure stem lodging, the trace of the panicle neck is an ellipse of which major axis is culm length and minor axis is 0.64* culm length. When both stem lodging and root lodging occurred in a natural setting, the partitioning of lodging can be calculated by a formula using eccentricity of an ellipse, S=e*100/0.768(S is the ratio of stem lodging in the whole lodging, e is eccentricity of the ellipse). This method is expected to be useful in simple lodging partitioning. We could also calculate the partitioning of stem lodging and root lodging as units of angles as an accuracy method, by using a straight line calculated by differentiating a quadratic equation of stem deformation at the origin of the coordinates. These two methods for dividing root and stem lodging showed different values. However, each of them showed almost same values with different lodging degree in one plant.

절수에 의한 Mongolian gerbil 신장조직의 변화에 관한 형태학적 연구 (Morphological Study on the Changes in the Kidney of the Water-deprived Mongolian gerbil (Meriones unguiculatus))

  • 김무강;이근좌;정영길;송치원;이경열;박일권;이철호;이기훈;현병화;김길수
    • Applied Microscopy
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    • 제27권4호
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    • pp.433-452
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    • 1997
  • Mongolian gerbil (Meriones unguiculatus) has been as an animal model for studing the neurological diseases such as stroke and epilepsy because of the congenital incompleteries in Willis circle, as well as the investigation of water metabolism because of the long time-survival in the condition of water-deprived desert condition, compared with other species animals. In order to accomplish the this research, first of all another divided the laboratory animals 5 groups of which each group include the 5 animals. In this study were investigated the histological structure in the kidney, measured the plasma osmolalities at the time of sacrifice of indivisual animals, and the body weights every day during water-deprived. The results obtained in this study were summarized as followings: 1. The body weights and decreasing rates of the body weight in water-deprived mongolian gerbil groups were continuosly decreased. 2. The plasma osmolalities were increased from the 5th water-deprived day, after then the gradually increasing reached nearly its equilibrium state at the 10th water-deprived day. 3. The urine volumes were abruptly decreased from the 2th water-deprived day, after then the gradually decreasing patterns were reached nearly its equilibrium state at the 10th day, and stopped the 11th day. 4. In the light microscopical observation of the kidney, glomerular capillary loop thickening, mesangial matrix increasing, sclerosis, glomerular cystic atrophy, interstitial fibrosis, tubular dilatation, mononuclear interstitial inflammation, interstitial mineralization, and hyperplasia of the collecting duct epithelium in the cortex area, were observed from the 10th water deprived day, and the lesions were gradually severe changed as the time lapse. 5. In the electron microscopical findings of the kidney, the degenerative changes of endothelial cell, podocyte and mesangial cell in glomeruli were initially observed on the 10th water-deprived day as well as the degeneration of microvilli and intracellular organelle in the renal tubules.

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근사개념 지도를 위한 관련 지식의 교수학적 고찰 (A study on the pedagogical consideration of the related knowledge for teaching 'Approximation' conception)

  • 정영우;이목화;김부윤
    • 한국수학교육학회지시리즈E:수학교육논문집
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    • 제26권1호
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    • pp.137-154
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    • 2012
  • 미적분학에서 '근사(approximation)'는 핵심 개념 가운데 하나인데, 이를 설명하기 위한 기본 개념은 '접선(tangent)'이며, 접선은 특별한 조건을 가지는 '직선(line)'이다. 본 연구에서는 미적분학의 이론적 기초가 되는 이들 수학적 지식에 대해 중등학교 기하지도 관점에 기초하여 교수학적 고찰을 하고, 이와 관련하여 개연성 있는 지도를 위한 주안점과 지도 방안을 제안한다. 이를 위해 유클리드 기하학에서의 점, 선, 원, 직선, 접선, 근사에 대해 알아보고, 이를 해석 기하학으로 번역하는 과정을 통해 대수적 조작을 위한 수학적 지식들을 유의미하게 유도한다. 그리고 현대수학의 관점으로 이를 발전시켜 근사를 위한 수학적 지식들의 유선(流線, stream line)을 구성한다. 또한 이를 바탕으로 직선, 접선 그리고 근사에 관한 학교수학의 내용을 고찰하여 지도의 주안점과 지도 방안을 모색한다. 이러한 연구는 교사들에게 교수학적 내용지식을 주며, 이들 수학적 지식을 개연성 있게 지도할 수 있는 수업모델 개발에 대한 기초를 제공한다. 나아가 학생들에게 수학이 계통적 학문이라는 것과 학교수학이 뚜렷한 목적성 아래 구성된 활동이라는 것을 인식하게 한다.