• Title/Summary/Keyword: 등속도

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Calculation Method of Constant Linear Velocity Spiral Path for Pin-on-disk Abrasion Test using a Hollow Type Rock Sample (중공형 암석시편의 Pin-on-disk 마모시험을 위한 등속도 나선경로 계산방법)

  • Kang, Hoon;Kim, Dae-ji;Song, Changheon;Oh, Joo-Young;Cho, Jung-Woo
    • Tunnel and Underground Space
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    • v.30 no.4
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    • pp.394-403
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    • 2020
  • This technical note describes the calculation method of continuous constant linear velocity Archimedean spiral paths which are applied to the pin-on-disk abrasion test. Approximate constant linear velocity Archimedean spirals have unstable velocities in the very near region of the rotational origin. Thus, in this technical note, the offset distance from the rotational origin was given by using a hollow type rock sample to maintain the constant velocity during the test. Also, to connect the inward and outward spirals continuously, the information of start and end points were input on the next spiral path consecutively. Furthermore, the calculation program was developed to provide convenience for calculating constant linear velocity spirals according to the specimen dimension and abrasion test conditions.

A Study of Cultural Aspects of Kimchi in 「Banchandeungsok」 (「반찬등속」에 기록된 김치의 식문화적 고찰)

  • Lee, Sol;Ji, Myoung Soon;Kim, Hyang Sook
    • Korean journal of food and cookery science
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    • v.30 no.4
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    • pp.486-497
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    • 2014
  • "Banchandeungsok" is recipe book written by a woman from a noble family who lived in Cheongju during the late 1900s. The book has 9 among 46 Kimchi recipes. In this study, the literatures from 1700 to 1900s, "Jeungbosanlimkyeongje", "Gyuhapchongseo", "Siuijeonseo", "Buinpilji", "Bogamrok", and "Josenmussangsinsikyorijebeob" were reviewed to examine the significance of "Banchandeungsok" Kimchi in the aspect of food culture. The results are as follows. "Banchandeungsok" Kimchies were considered as typical type of Kimchi of the late Joseon, and the main ingredients include Chinese cabbage, white radish, and cucumber. Salted-fish juice was not used for making Mukimchi, Bachujjanji, Jjanji in "Banchandeungsok", and gallic, ginger, green onion were used as main spice. Therefore, "Banchandeungsok" Kimchies belongs to Damjeo (light salting) type, which is characterized by light and clear flavor of present Cheongju Kimchi. While salted-fish juice was not used for "Banchandeungsok" Kimchies, yellow corbina was used in the most of "Banchandeungsok" Kimchies. Various forms of pepper were used in "Banchandeungsok" Kimchies - green pepper, peper leaf, minced, sliced shredded and powdered red pepper. Two kinds of Kkakdugi were introduced in "Banchandeungsok", which is the first record in the literatures. A typical type of stuffed cucumber pickles and unique type of cucumber Kimchi appeared in "Banchandeungsok".

Correlation between Korean Shoulder Scoring System and Isokinetic muscle strength test (Korean Shoulder Scoring System과 Isokinetic test를 통한 근력 평가의 상관 관계)

  • Kim, Deok-Weon;Sung, Jung-Hwan;Jung, Jae-Eun;Ko, Min-Soo
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.9 no.2
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    • pp.104-108
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    • 2010
  • Purpose: To evaluate the correlation between Korean Shoulder Scoring System and Isokinetic muscle strength test for allowance of the return to unrestricted activities after rotator cuff disease treatment. Materials and Methods: This study examined 59 patients with impingement syndrome and 36 patients with rotator cuff tear. KSS and isokinetic muscle strength were analyzed and we sought to evaluate the correlation between total score or each functional parameter scores of KSS and isokinetic muscle strength deficit with Pearson's correlation test. Results: We found a weak negative correlation between and the total KSS score and the endurance test as well (r<0.346). The correlation between the manual muscle test of KSS and isokinetic strength deficits was not significant (p>0.05). Conclusion: The isokinetic muscle strength deficit had a weak correlarion between total score or the edurance test of KSS. Our results suggest that the Isokinetic muscle strength test may be needed for return to normal activity after treatment.

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Approximate Solution for Constant Velocity of Archimedean Spiral for Abrasion Testing of Rock Cutting Tools (암석공구 마모시험을 위한 아르키메데스 나선의 등속도 운동 근사해 조사)

  • Kang, Hoon;Kim, Dae-ji;Song, Changheon;Oh, Joo-Young;Cho, Jung-Woo
    • Tunnel and Underground Space
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    • v.30 no.3
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    • pp.181-192
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    • 2020
  • Pin-on-disk test is a suggested abrasion testing method by ASTM (American Society for Testing and Materials). This briefly illustrated the Archimedean spiral motion of a pin type specimen on a disk. To apply this method to rock cutting tools, a constant linear velocity (CLV) is precisely maintained during the test. We defined the two velocity vectors (RPM and horizontal speed) which connected to the resultatnt velocity. We derived a differential equations for the two parameters under CLV condition. It was difficult to find a exact solution. Previous literatures had been reviewed, and an approximate solution was investigated. We mathematically simulated the result for a certain parameter, and examine the accuracy of the solution.

Difference in Quadriceps and Hamstring torque during exercise with concentric and eccentric contractions according to hip joint anglet (등속성 근력측정 시 Hip Joint Angle에 따른 대퇴사두근과 햄스트링의 단축성과 신장성 근력 차이)

  • Kim, eui-young;Lee, jong-hwan
    • Proceedings of the Korea Contents Association Conference
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    • 2010.05a
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    • pp.161-163
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    • 2010
  • 본 연구의 목적은 등속성 운동수행 및 측정시 hip joint angle에 따라 대퇴근육의 concentric 과 eccentric 근력차이를 분석하기 위하여 등속성 기기 의자 등받이 경사각도를 $100^{\circ}$, $120^{\circ}$, $140^{\circ}$에서 peak torque를 검사하였다. 대상자는 20대 초반의 건강한 남자 대학생 12명을 대상으로, 등속성 기기(Isomed 2000, Germany)를 이용하여 seated position에서 $60^{\circ}/s$ 의 각속도를 사용하여 검사를 수행하였다. 측정순서는 등속성기기 의자 등받이 경사각도 $100^{\circ}$, $120^{\circ}$, $140^{\circ}$ 순으로 2-3일 간격으로 진행하였다. 통계처리 방법은 SPSS 12.0 프로그램을 이용하여 평균과 표준편차를 산출하였으며, 각각의 hip angle에 따른 단축성과 신장성 peak torque 값의 차이는 one-way ANOVA(3RM)을 이용하여 처리하였고, 사후검증은 Tukey를 사용하였으며, 유의수준은 p<.05로 하였다. 연구결과 대퇴사두근의 단축성 근력은 등속성 기기 의자 등받이 경사각 $100^{\circ}$, $120^{\circ}$, $140^{\circ}$사이에 유의한 차이(p=.000)가 나타나 사후 분석결과 $100^{\circ}$$120^{\circ}$ 사이(p<.01) 그리고 $100^{\circ}$$140^{\circ}$ 사이(p<.001)에 유의한 차이를 나타내었으며, 신장성 근력에서는 유의한 차이가 나타나지 않았다. 햄스트링의 단축성 근력은 3종류의 hip angle사이에 유의한 차이(p=.001)가 나타나 사후분석결과 $100^{\circ}$$140^{\circ}$사이(p<.05) 그리고 $120^{\circ}$$140^{\circ}$ 사이(p<.01)에 유의한 차이를 나타내었으며, 그러나 신장성 근력에서는 유의한 차이가 나타지 않았다. 이러한 결과로 미루어 볼 때 등속성 운동수행 및 근력측정 시 hip joint angle 에 따라 대퇴사두근과 햄스트링의 단축성 근력에서 유의한 차이가 나타나 hip joint angle을 고려하여 대퇴근육의 운동및 측정이 이루어져야 할 것으로 사료된다.

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Analytic Study on the Axial Forces of a Double Offset Constant Velocity Joints in Consideration of Friction Effect (마찰을 고려한 이중 오프셋 등속조인트의 축력 해석에 관한 연구)

  • Bae, Byoung-Chul
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.2
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    • pp.120-127
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    • 2008
  • The constant velocity joint(CVJ) used for transmitting torque to the front wheels is an important part in automotive drive system. There are several types of constant velocity joints. Typically, they are classified by fixed and plunging constant velocity joints. The axial force generated in plunging constant velocity joints influences significantly the noise, vibration and harshness. For heaps of time, many constant velocity joint markers have been studying and developing a valid method to reduce the axial force and extensive tests have been carried out on rigs. This paper presents the analysis method to predict the axial force of a double offset constant velocity joint(DOJ), a kind of plunging constant velocity joint, and the influence of ball-cage dimension tolerance on the axial force.

A Convergence Study through Durability Analysis due to the Shaft Length of Automotive Constant Velocity Joint (자동차 등속 조인트 샤프트 길이에 따른 내구성 해석을 통한 융합연구)

  • Choi, Gye-Gwang;Cho, Jae-Ung
    • Journal of the Korea Convergence Society
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    • v.9 no.8
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    • pp.179-184
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    • 2018
  • The driving methods of car are front wheel drive, rear wheel drive and four wheel drive. At driving methods, constant velocity joint is the most important part at carrying out two functions for converting to the direction which the driver wants and transferring the power to wheels. At driving on the road, the impact can be applied to the parts transmitting power according to the state of road surface. In this study, each models of three constant velocity joints whose shaft length are different respectively were modelled with CATIA and the structural and fatigue analyses were carried out by using ANSYS. This study result is thought to be the useful material at designing the constant velocity joint with the durability against impact. And it is possible to be grafted onto the convergence technique at the design of constant velocity joint and show the esthetic sense.

Identification of Spastic Joint Pathologies using Isokinetic Movement (등속운동을 이용한 경직성 관절장애 정량화)

  • Lee Chang-Han;Heo Ji-Un;Kim Chul-Seung;Eom Gwang-Moon
    • Science of Emotion and Sensibility
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    • v.7 no.4
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    • pp.19-24
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    • 2004
  • The purpose of this study is to evaluate the possibility of identifying joint damping property through commercially available isokinetic ergometer (BIODEX). The proposed method is to estimate the damping torque of the knee joint from the difference between the external joint torque for maintaining isokinetic movement and the gravity torque of the lower leg. The damping torque was estimated at various joint angular velocities, from which the damping property would be derived. Measurement setup was composed of the BIODEX system with an external force sensor and Labview system. Matlab was used in the analysis of the damping property. The experimental result showed that the small variation in angular velocity due to acceleration and deceleration of the crank arm resulted in greater change of inertial torque than the damping torque. Therefore, the estimation of damping property from the isokinetic movement is difficult.

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A study on walking algorithm of quadruped robot used stroke control method in the irregular terrain (비평탄 지형에서 스토로크 제어법을 이용한 4족 로봇의 보행 알고리즘에 관한 연구)

  • Ahn, Young-Myung
    • 전자공학회논문지 IE
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    • v.43 no.4
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    • pp.52-59
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    • 2006
  • Walking robot is able to move in regular or irregular terrain. It can walk that change adaptive algorithms according to the terrain. Existing papers about adaptive gaits of blind robot are based on intelligent foothold selection. However, this paper proposes a algerian that is based on the variations of stroke and period to adapt the irregular terrain. If thus adaptive algorithms is used, robot can maintain periodic gait walking and constant speed using only force sensor even in the irregular terrain without external sophisticated sensor. In this paper Quadruped robot with 2 DOF in each leg, is walk experiment with the wave gait in regular and irregular terrain. So the adaptive algorithm is proved useful through walk experiment.