• Title/Summary/Keyword: Motor Characteristic

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A Study on Rotation Method Appling Slip-ring of Direction Finding Antenna Mast for Mobile Radio Wave Measurement System (이동형 전파측정시스템에서 슬립링을 적용한 방향탐지 안테나 마스트 회전 방법에 관한 연구)

  • Sohn, Ju-Hang;Han, In-Sung;Kim, Duck-Joong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.10
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    • pp.499-504
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    • 2017
  • A Mobile Radio Wave Measurement System (MRWMS)is a vehicle-mounted system designed to be operating in a single mission. The mission characteristic for mobile measurement requires mobility. For this, we must consider the arrangement and embedded method of MRWMS's antennas. In this paper, we described the measurement method design of direction detecting accuracy for MRWMS and designed the direction finding antenna mast capable of rotating itself by using a slip ring without turntable for Direction Finding (DF) accuracy test. As we removed the dependency of a limited local area by designing a measurement method of direction detecting accuracy, Equipment Under Test (EUT) zero-Adjustment and mounted process shortened. So, we the reduced production costs. We expect an improved cable loss value by shortening the RF cable length in accordance with our design. In addition, due to the same phenomenon, the entire system is lighter and the mobility is improved.

The Development of a Multi-Purpose Irradiator and the Characteristic of Dose Distribution (다목적 방사선 조사장치 개발 및 선량분포특성)

  • Lee, Dong-Hoon;Ji, Young-Hoon;Lee, Dong-Han;Kim, Yoon-Jong;Hong, Seung-Hong
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.39 no.6
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    • pp.42-48
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    • 2002
  • The design, construction and performance test of a convenient multi-purpose irradiator is described. A multi-purpose irradiator using Cesium-137 has been developed for studies of low dose radiation effects in biology and for calibration of Thermo Luminescent dosimeter(TLD). During the operation, three rods of radioactive material which are 10cm in length revolve 180 degrees and irradiate biological samples, or TLD, and return to their shielded position, after the programmed time. A programmable Logic Controller(PLC) controls the sequence of operation, interlock, motor rotation and safety system. The rotation speed of biological samples can vary up to 20 RPM. A real time monitoring system was also incorporated to check and control the operation status of the irradiator. The capacity of the irradiation chamber was 4.5 liters. The isodose distribution at arbitrary vertical planes was measured by using film dosimetry. The dose-rate was 0.13 cGy/min in air and 0.11 cGy/min in water equivalent material in the case of Cesium-137. Range of activity was 2 Ci. The homogeneity of dose distribution in the chamber was ${\pm}$7%. The actual radiation level on the surface was within permissible levels. The irradiator had a maximum 0.35 mR/min radiation leakage on its surface.

A CASE OF CORENELIA DE LANGE SYNDROME WITH MENTAL RETARDATION AND AUTISTIC DISORDER (정신지체와 자폐장애를 보이는 Cornelia De Lange 증후군 1예)

  • Kim, Se-Joo;Choi, Nak-Kyoung;Song, Jung-Eun
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.14 no.1
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    • pp.123-127
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    • 2003
  • Cornelia de Lange syndrome is a dysmorphogenic disorder characterized by multiple congenital abnormalities, mental retardation, growth retardation and neurodevelopmental abnormalities. Diagnosis for the Cornelia de Lange syndrome is dependent on the clinical observation because neither definite biological marker nor definite chromosomal abnormality have been investigated. Clinical observation is important for the diagnosis, so we report a case of Corenelia de Lange syndrome with mental retardation and autistic disorder. The patient is a 6-year old girl. Her motor development and language development have been delayed. She could say no meaningful word and understood simple command partially. She showed poor eye contact and poor emotional interaction. Social interaction was impaired and she Showed stereotypic behaviors. Thus we diagnosed her as mental retardation with autistic disorder. She had vesicoureteral reflux, frequent upper respiratory infection and pneumonia. She had experienced febrile convulsions 4 times. She had short stature, confluent eyebrows, long eyelashes, and upturned nose with anteverted nostrils. She also showed low hairline and hypertrichosis in body and extremities. Her finger was short. In this case, we diagnosed Cornelia de Lange syndrome by her characteristic face, hypertrichosis and medical and behavioral problems that were frequently showed in this syndrome.

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A Strategy of a Gap Block Design in the CFRP Double Roller to Minimize Defects during the Product Conveyance (제품 이송 시 결함 최소화를 위한 CFRP 이중 롤러의 Gap block 설계 전략)

  • Seung-Ji Yang;Young-june Park;Sung-Eun Kim;Jun-Geol Ahn;Hyun-Ik Yang
    • Composites Research
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    • v.37 no.1
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    • pp.7-14
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    • 2024
  • Due to the structural characteristic of a double roller, the double roller can have various deformation behaviors depending on a gap block design, even if dimensions and loading conditions for the double roller are the same. Based on this feature, we propose a strategy for designing the gap block of the carbon-fiber reinforced plastic (CFRP) double roller to minimize defects (e.g., sagging and wrinkling), which can be raised during the product conveying process, with the pursue of the lightweight design. In the suggested strategy, analysis cases are first selected by considering main design parameters and engineering tolerances of the gap block, and then deformation behaviors of these selected cases are extracted using the finite element method (FEM). Here, to obtain the optimal gap block parameters that satisfy the purpose of this study, deformation deviations in the contact area are calculated and compared using the extracted deformation behaviors. Note that the contact area in this work is located between the product and the roller. As a result, through the design method of the gap block proposed in this work, it is possible to construct the CFRP double roller that can significantly decrease the defects without changing the overall sizes of the roller. A detailed method is suggested herein, and the results are evaluated in a numerical way.

Neuroprotective Effect of Phenytoin and Hypothermia on a Spinal Cord Ischemic Injury Model in Rabbits (토끼의 척수 허혈 손상 모델에서 페니토인과 저체온의 신경 보호 효과의 비교)

  • Oh, Sam-Sae;Choe, Ghee-Young;Kim, Won-Gon
    • Journal of Chest Surgery
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    • v.41 no.4
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    • pp.405-416
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    • 2008
  • Background: Spinal cord ischemic injury during thoracic and thoracoabdominal aortic surgeries remains a potentially devastating outcome despite using various methods of protection. Neuronal voltage-dependent sodium channel antagonists are known to provide neuroprotection in cerebral ischemic models. This study was designed to compare the neuroprotective effects of phenytoin with those of hypothermia in a rabbit model of spinal cord ischemia. Material and Method: Spinal cord ischemia was induced in New Zealand white rabbits by means of infrarenal aortic cross clamping for 25 minutes. Four groups of 8 animals each were studied. The control group and the hypothermia group received retrograde infusion of saline only ($22^{\circ}C$, 2 mL/min); the normothermic phenytoin group and the hypothermicphenytoin group received retrograde infusion of 100 mg of phenytoin at different rectal temperatures ($39^{\circ}C$ and $37^{\circ}C$, respectively) during the ischemic period. The neurologic function was assessed at 24 and 72 hours after the operation with using the modified Tarlov criteria. The spinal cords were harvested after the final neurologic examination for histopathological examination to objectively quantify the amount of neuronal damage. Result: No major adverse effects were observed with the retrograde phenytoin infusion during the aortic ischemic period. All the control rabbits became severely paraplegic, Both the phenytoin group and the hypothermia group had a better neurological status than did the control group (p < 0.05). The typical morphological changes that are characteristic of neuronal necrosis in the gray matter of the control animals were demonstrated by means of the histopathological examination, whereas phenytoin or hypothermia prevented or attenuated these necrotic phenomena (p < 0.05). The number of motor neuron cells positive for TUNEL staining was significantly reduced, to a similar extent, in the rabbits treated with phenytoin or hypothermia. Phenytoin and hypothermia had some additive neuroprotective effect, but there was no statistical significance between the two on the neurological and histopathological analysis. Conclusion: The neurological and histopathological analysis consistently demonstrated that both phenytoin and hypothermia may afford significant spinal cord protection to a similar extent during spinal cord ischemia in rabbits, although no significant additive effects were noticed.