• 제목/요약/키워드: Inclined Plane

검색결과 207건 처리시간 0.019초

비균질 Helmholtz 방정식을 이용한 변동 수심에서의 파랑변형 (Inhomogeneous Helmholtz equation for Water Waves on Variable Depth)

  • 김효섭;장창환
    • 한국해양환경ㆍ에너지학회지
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    • 제13권3호
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    • pp.174-180
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    • 2010
  • 변동 수심에서의 파랑변형을 비균질 Helmholtz 방정식을 이용하여 계산하였다. 포텐셜 함수가 존재한다고 가정하였으며, 변수분리를 적용하였다. 본 논문에서는 조화파만을 고려하였다. 포텐셜 함수로 구성된 지배방정식을 정수면에 직접 적용하였고, 변동 수심에 대한 비균질 Helmholtz 방정식을 얻었다. 파랑의 진폭과 위상차로 얻어진 복합 포텐셜 함수의 지배방정식을 실수형 변수로 된 두 방정식으로 분리하였다. 분리된 방정식들은 각각 1차와 2차 상미분 방정식이며, 이 방정식들을 단순한 형태의 중앙차분 수치기법을 이용하여 차분식으로 변형하였다. 측면 경계조건에서의 파랑의 진폭, 진폭경사, 그리고 위상경사를 경계면에 적용하여 전방진행방법으로 전 영역에서 해를 구하였다 Booij의 경사면 있는 저면의 경우와 Bragg의 물결모양이 있는 저면의 경우에 적용하였다. 본 연구로 도출된 비균질 Helmholtz 방정식은 완전 선형방정식 계산 결과, Massel의 수정 완경사 방정식, 그리고 Berkhoff의 완경사 방정식의 적용 결과와 비교하였으며, 만족스러운 결과를 얻었다.

Measurement of Mechanical and Physical Properties of Pepper for Particle Behavior Analysis

  • Nam, Ju-Seok;Byun, Jun-Hee;Kim, Tae-Hyeong;Kim, Myoung-Ho;Kim, Dae-Cheol
    • Journal of Biosystems Engineering
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    • 제43권3호
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    • pp.173-184
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    • 2018
  • Purpose: This study was conducted to investigate the mechanical and physical properties of a Korean red pepper variety for particle behavior analysis. Methods: Poisson's ratio, modulus of elasticity, shear modulus, density, coefficient of restitution, and coefficient of friction were derived for "AR Legend," which is a domestic pepper variety. The modulus of elasticity and Poisson's ratio were measured through a compression test using a texture analyzer. The shear modulus was calculated from the modulus of elasticity and Poisson's ratio. The density was measured using a water pycnometer method. The coefficient of restitution was measured using a collision test, and the static and dynamic friction coefficients were measured using a inclined plane test. Each test was repeated 3-5 times except for density measurement, and the results were analyzed using mean values. Results: Poisson's ratios for the pepper fruit and pepper stem were 0.295 and 0.291, respectively. Elastic moduli of the pepper fruit and pepper stem were $1.152{\times}10^7Pa$ and $3.295{\times}10^7Pa$, respectively, and the shear moduli of the pepper fruit and pepper stem were $4.624{\times}10^6Pa$ and $1.276{\times}10^7Pa$, respectively. The density of the pepper fruit and the pepper stem were $601.8kg/m^3$ and $980.4kg/m^3$, respectively. The restitution coefficients between pepper fruits, pepper stems, a pepper fruit and a pepper stem, a pepper fruit and plastic, and a pepper stem and plastic were 0.383, 0.218, 0.277, 0.399, and 0.148, respectively. The coefficients of static friction between pepper fruits, pepper stems, a pepper fruit and a pepper stem, a pepper fruit and plastic, and a pepper stem and plastic were 0.455, 0.332, 0.306, 0.364, and 0.404, respectively. The coefficients of dynamic friction between a pepper fruit and plastic and a pepper stem and plastic were 0.043 and 0.034, respectively.

양혈장근건보탕(養血壯筋健步湯)과 전침의 병용치료가 손상된 척수신경 및 운동기능에 미치는 영향 (Effects of Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) and Electrical Acupuncture on the Spinal Nerve Injury and the Motor Function)

  • 설재욱;추민규;김선종;최진봉;신미숙;김수익
    • 한방재활의학과학회지
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    • 제19권2호
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    • pp.1-25
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    • 2009
  • Objectives : The purpose of this study was to investigate the effects of Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang, YGKT) and electrical acupuncture treatment in spinal cord injury(SCI)-induced rats. Methods : The subjects were divided into 5 groups ; Normal, Control-no treatment after SCI, Experimental I(Exp. I)-taken with YGKT 500 mg/kg $0.5m{\ell}$ daily after SCI. Experimental II(Exp. II)-taken with electrical acupuncture after SCI and Experimental III(Exp. III)-taken with YGKT 500 mg/kg $0.5m{\ell}$ and electrical acupuncture after SCI. After each operation, the present author observed cytological changes, the motor behavior recovery and nerve regeneration by analysis of the motor behavior tests, EMG, hematological(AST, ALT, WBC), histological and immunological changes. Rats were tested by Motor behavior test at 1st, 3rd, 7th, 14th and 21st day. Results : 1. All the experimental groups were improved compared with control group in the motor behavior tests including Tarlov test, Basso-Beattle-Bresnahan locomotor rating scale, modified inclined plane test, open field test, grid walk test and narrow beam test. Especially Exp. III was significantly improved among other groups. 2. In EMG test, H and M wave were significantly increased in Exp. III. 3. All the experimental groups were significantly decreased compared with control group in AST, ALT and WBC. 4. NGF, BDNF and Trk B of spinal cord gray matter in all the experimental groups were increased compared with control group. Especially, Exp. III was more effective. 5. In histological observations, muscle contraction and denaturation of gastrocnemius muscle of all the experimental groups were inhibited. Especially, those of Exp. III was more effective. On the observations of liver and kidney, cell atrophy and apoptosis of all the experimental groups were decreased compared with control group. Especially, those of Exp. III was more effective. Conclusions : It can be suggested that YGKT and electrical acupuncture may improve motor behavior, EMG, hematological, histological and immunological findings in SCI-induced rats. Especially, combination of these two treatments will be somewhat better in spinal nerve recovery and motor function improvement.

양혈장근건보탕(養血壯筋健步湯)과 녹용약침(鹿茸藥鍼)이 척수손상 유발 흰쥐의 운동기능 회복 및 신경재생에 미치는 영향 (Effects of Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) and Cervi Cornu Parvum Pharmaco-Acupuncture on the Motor Function Recovery and Nerve Regeneration in Rats Induced Spinal Cord Injury)

  • 박지용;설재욱;김선종;최진봉;신미숙
    • 한방재활의학과학회지
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    • 제19권2호
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    • pp.27-49
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    • 2009
  • Objectives : The purpose of this study was to investigate the effects of Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) and Cervi Cornu Parvum pharmaco-acupuncture in Spinal Cord Injury(SCI)-induced rats. Methods : The subjects were divided into 5 groups ; Normal, Control no treatment after SCI, Experimental I taken with Yanghyuljanggeungunbo-tang (Yangxuezhuangjinjianbu-tang) 500 mg/kg $0.5m{\ell}$ daily after inducing SCI. Experimental II taken with Cervi Cornu Parvum pharmaco-acupuncture at Taegye(KI3) and $Yangnungch{\acute{o}}n$(GB34) after inducing SCI and Experimental III taken with Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) 500 mg/kg $0.5m{\ell}$ and Cervi Cornu Parvum pharmaco-acupuncture at KI3 and GB34 to SCI-induced rats. After each operation, the present author observed the motor behavior recovery and nerve regeneration by analysis of the motor behavior tests, EMG, hematological(AST, ALT, WBC), histological and immunological changes. Rats were tested at modified Tarlov test at the 1st, 2nd, 3rd, 4th day, and Motor behavior test at 1st, 3rd, 7th, 14th, 21st day. Results : Results are as follows. 1. All the experimental groups were improved compared with control group in the motor behavior tests including Tarlov test, Basso-Beattle-Bresnahan locomotor rating scale, modified inclined plane test, open field test, grid walk test and narrow beam test. Especially Experimental III was improved significantly among other groups. 2. In EMG test, H wave appeared weak only in Experimental III. And M wave was increased significantly in Experimental III. 3. All the experimental groups were significantly decreased compared with control group in serum AST, serum ALT and serum WBC tests. 4. significantly decreased in Tumor Necrosis Factor-${\alpha}$ test compared with the first day of SCI. 5. Muscle contraction and denaturation of all the experimental groups were inhibited in histological observations of gastrocnemius muscle. Especially, those of experimental III was more effective. 6. NGF and BDNF of spinal cord gray matter in all the experimental groups were increased compared with control group. Especially, those of experimental III was more effective. Conclusions : As above, it can be suggested that Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) and Cervi Cornu Parvum pharmaco-acupuncture may improve motor behavior, EMG, hematological, histological and immunological findings in Spinal Cord Injury(SCI)-induced rats. Especially, effects will be somewhat better in combination of these two treatments.

ProTaper Universal에 축적된 내부 응력이 피로 파절에 미치는 영향 (Effect of Internal Stress on Cyclic Fatigue Failure in ProTaper Universal)

  • 조윤성;김진우;조경모;박세희
    • 구강회복응용과학지
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    • 제28권1호
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    • pp.57-66
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    • 2012
  • 본 연구는 ProTaper Universal에 의도적으로 부여한 내부 응력이 피로 파절에 미치는 영향을 평가하였다. 25 mm 길이의 S1, S2, F1, F2, F3, F4 그리고 F5 파일을 내부 응력을 부여하기 위해서 Endo-Training-Bloc (Dentsply Maillefer)에 auto-stop 될 때까지 속도 300 rpm, 토크 1.0 Ncm의 값으로 밀어 넣었다. 부여한 내부 응력의 횟수에 따라 각각 Stress 0 군(대조군), Stress 1 군, Stress 2 군 그리고 Stress 3 군으로 분류하였다. 경사진 유리판을 사용하였고 파일 파절 시간을 측정하였다. 모든 파일에서는 Stress 3 군은 대조군에 비해 Ni-Ti 파일의 파절 시간이 감소하였고 F2와 F3에서 모든 실험군은 대조군에 비해 파절 시간이 감소하였다. F4와 F5에서 Stress 2 군과 Stress 3 군이 대조군에 비해 파절 시간이 감소하였다. ProTaper Universal의 피로 파절은 파일에 축적된 내부 응력에 의해 영향을 받는다.

트레드밀 운동이 척수손상 백서의 운동기능 회복에 미치는 효과 (The Effects of Treadmill Exercise on the Recovery of Functional Capacity in Spinal Cord Injured Rats)

  • 천진성;김태열;남기원;김용억;오명화;김경윤;김은정;이재춘;장미경;최현석;허명;김계엽
    • The Journal of Korean Physical Therapy
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    • 제19권4호
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    • pp.15-24
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    • 2007
  • Purpose: This study was designed to investigate the effects of treadmill exercise on functional recovery after rat with experimental SCI. Methods: SCI was induced by the NYU-spinal cord impactor(NYU, USA) dropped a weight of 10 gm after laminectomy. Experimental groups were divided into the Group I (normal), Group II (control) and Group III(treadmill exercise). After 2 days of the operation, 24 rats(group II, III) were trained to walk on treadmill for 21 days twice/day, 15 min/session. After operation, rats were tested at modified Tarlov scale at 1, 2, 3, 4 days with divided into 2 groups, and Motor behavior test(BBB locomotor rating scale, Grid walking test, Narrow beam crossing test, Modified inclined plane test) was examined at 1, 3, 7, 14 and 21 days. Histopathological study were performed at 1. 3, 7, 14 and 21 days by H&E, Luxol Fast Blue staining were same times. Results: After SCI an improvement of motor behavior was shown group II, III. The motor behavior test of group Ill showed considerable improvement until 14 days. Conclusion: These results suggest that treadmill exercise treatment can playa role in facilitating recovery of locomotion following spinal cord injury.

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『묵경』 중의 물체 운동에 관한 이론 고찰 (The Thought of the theory about the laws of motion in 『Mojing』)

  • 황성규
    • 한국철학논집
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    • 제29호
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    • pp.203-230
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    • 2010
  • 이 글은 『묵경』 속에 내재된 물체 운동에 관한 이론들, 가령 축성(築城) 과정에서 제기된 중력 원리의 초보적 접근, 생산력 증대를 위해 고안된 지레와 도르래, 빗면 원리의 이해와 활용 등을 중심으로 살펴보고 그것이 지닌 과학적 의의를 규명함으로써 묵가의 합리성을 제시하는데 그 목적이 있다. 이 글은 묵자를 위시한 묵가들이 수공업에 종사하는 특수한 신분이었기 때문에 기술의 발전과 백성들의 삶에 긍정적인 영향을 끼칠 수 있었다는 견해를 재조명함으로써 묵가 과학 사상의 궁극적 지향점을 제시하고자 한다. 묵가는 백성들의 인간다운 삶이 보장된 사회 구축을 위해서는 과학이 무엇보다 중요하다는 사실을 가장 먼저 깨달은 선진학파 중 하나이며, 과학을 통해 재화가 풍족한 사회를 추구한 선각자들이다. 따라서 묵가가 제기한 과학 이론들은 단순한 사물의 현상을 관찰하고 그것에 내재된 규칙성을 이끌어 내는데 주안점이 있었던 것이 아니었고, 반드시 민리(民利)가 전제되고 또 그것과 긴밀한 연계를 가질 때에만 이론화될 수 있었다. 20세기 초 중국 사상계에서는 묵가가 지닌 과학 사상에 주목하며 그것에 대한 연구를 활발히 진행하였는데, 특히 물체 운동과 관련된 묵가의 견해는 서양의 역학 이론에 버금가는 탁월한 이론으로 이해되었고, 애민 사상에 기초한 묵가 사상의 정신과 의의를 여실히 반영하고 있다고 생각하였다. 특히 묵가가 제창한 물체 운동과 관련된 이론들은 당시에도 변함없이 실생활에 활용되고 있었기 때문에 묵가 사상에 대한 백안시 혹은 방치가 중국 과학 발전의 걸림돌이 되었다고 자책하기도 하였다.