• 제목/요약/키워드: continuous contact

검색결과 378건 처리시간 0.035초

비접촉 방식의 생체 신호 측정을 위한 도플러 레이더 시스템 (Doppler Radar System for Noncontact Bio-signal measurement)

  • 신재연;조성필;장병준;박호동;이윤수;이경중
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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    • pp.357-359
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    • 2009
  • In this paper, the 2.4GHz doppler radar system consisting of the doppler radar module and a baseband module were designed to detect heartbeat and respiration signal without direct skin contact. A bio-radar system emits continuous RF signal of 2.4GHz toward human chest, and then detects the reflected signal so as to investigate cardiopulmonary activities. The heartbeat and respiration signals acquired from quadrature signal of the doppler radar system are applied to the pre-processing circuit, amplification circuit, and the offset circuit of the baseband module. ECG(electrocardiogram) and reference respiration signals are measured simultaneously to evaluate the doppler radar system. As a result, the respiration signal of doppler radar signal is detected to 1m without complex digital signal processing. The sensitivity and calculated from I/Q respiration signal were $98.29{\pm}1.79%$, $97.11{\pm}2.75%$, respectively, and positive predictivity were $98.11{\pm}1.45%$, $92.21{\pm}10.92%$, respectively. The sensitivity and positive predictivity calculated from phase and magnitude of the doppler radar were $95.17{\pm}5.33%$, $94.99{\pm}5.43%$, respectively. In this paper, we confirmed that noncontact real-time heartbeat and respiration detection using the doppler radar system has the possibility and limitation.

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Comparison of the Fatigue Behaviors of FRP Bridge Decks and Reinforced Concrete Conventional Decks Under Extreme Environmental Conditions

  • Kwon, Soon-Chul;Piyush K. Dutta;Kim, Yun-Hae;Anido, Roberto-Lopez
    • Journal of Mechanical Science and Technology
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    • 제17권1호
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    • pp.1-10
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    • 2003
  • This paper summarizes the results of the fatigue test of four composite bridge decks in extreme temperatures (-30$^{\circ}C$ and 50$^{\circ}C$ ). The work was performed as part of a research program to evaluate and install multiple FRP bridge deck systems in Dayton, Ohio. A two-span continuous concrete deck was also built on three steel girders for the benchmark tests. Simulated wheel loads were applied simultaneously at two points by two servo-controlled hydraulic actuators specially designed and fabricated to perform under extreme temperatures. Each deck was initially subjected to one million wheel load cycles at low temperature and another one million cycles at high temperature. The results presented in this paper correspond to the fatigue response of each deck for four million load cycles at low temperature and another four million cycles at high temperature. Thus, the deck was subjected to a total of ten million cycles. Quasi-static load-deflection and load-strain responses were determined at predetermined fatigue cycle levels. Except for the progressive reduction in stiffness, no significant distress was observed in any of the composite deck prototypes during ten million load cycles. The effects of extreme temperatures and accumulated load cycles on the load-deflection and load-strain response of FRP composite and FRP-concrete hybrid bridge decks are discussed based on the experimental results.

수직 진동을 이용한 가열된 고체표면 위 증발하는 액적의 내부유동 제어연구 (Study of the Internal Flow and Evaporation Characteristic Inside a Water Droplet on a Vertical Vibrating Hydrophobic Surface)

  • 박창석;임희창
    • 대한기계학회논문집B
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    • 제41권1호
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    • pp.37-46
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    • 2017
  • 가열된 표면에서의 액적은 일반적으로 내부에 마랑고니 유동이 발생하고, 이는 불균일한 침전물 패턴 형상을 구성하게 된다. 본 연구는 마랑고니 유동을 가시화하고, 수직진동을 사용해서 이를 제어하는 것을 주 목적으로 한다. 액적이 증발하는 동안, 액적의 접촉각 변화와 부피변화를 실험적으로 알 수 있었고, PIV(Particle Image Velocimetry) 실험 장치를 이용하여, 평판 온도별 마랑고니 유동의 내부 유동의 흐름을 가시화하였다. 그리고 평판에 각 주파수별 수직진동을 가해주는 실험을 진행하여, 그 결과 마랑고니 유동의 유동 방향과 수직진동의 유동 방향이 서로 반대인 것을 확인할 수 있었다. 마지막으로 증발하는 액적에 수직진동을 가해줌으로써, 액적의 하단부분에서 내부유동의 흐름변화를 관찰하였다. 마랑고니유동에 의해 발생하는 내부유동 방향과 수직진동으로 발생하는 내부유동의 방향이 서로 반대 방향이므로 가열된 평판에 진동을 가해주었을 때 액적 내부유동의 흐름이 변화가 발생하였고, 이는 곧 불균일한 침전물 패턴이 억제된 것을 증발 후 침전물의 패턴형상을 통해 확인할 수 있었다.

복심곡선 레일이상마모 발생 저감 사례 (The Reduction Case of Occurrence of Abnormal Wearing of Rail in Compound Curve Part)

  • 김완술
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2007년도 춘계학술대회 논문집
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    • pp.1097-1106
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    • 2007
  • Rail provides running tract for train and broadly and widely conveys the weight of the train exerted from the train wheels that the rail directly supports onto the cross tie and roadbed, and supports the cross-sectional pressure exerted by centrifugal force at curvatures. That is, stationary rail provides surface on which dynamic train runs and guarantees cross-sectional resistance to enable the vertical snake motion of the train wheels as well as to maintain lateral force at curvatures. Rail provides running surface on which train wheels can run smoothly, and secures vertical and lateral force. However, it undergoes continuous destructive reactions (wearing and damages) and abrasion of the cladding by the train wheels. It is obvious that wearing will result when two metal parts act against each other. However, occurrence of abnormal wearing such as rapid wearing of the rail side due to complex generation of various mechanisms at the contact surface between the rail and train wheel flange. It is not easy to simply examine the causes of occurrence of abnormal wearing of rail and train wheel flange. Although countless number of academicians and specialists are conducting researches on abnormal wearing of rail and vertical wearing of train wheels, I believe it is too early to argue on pros and cons due to insufficiency of officially verified information on the issue. This review will be focusing on the examples of repairs that reduced the generation of abnormal wearing of rail by reviewing and improving characteristics of wearing and slack, speed of the train and cant as well as status of lubricator by choosing the compound curves present in the section between the $Anguk{\sim}Jongno3-ga$ Stations of the Route No. 3 among the compound curve tracks of the Seoul Metro Routes No. 3 & 4 at which abnormal wearing is generated continuously.

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물 재이용을 위한 하수처리장 방류수 색도의 자외선처리에 미치는 과산화수소의 영향 (Effect of Hydrogen Peroxide on UV Treatment of Color in Secondary Effluent for Reclamation)

  • 박기영;맹승규;김기팔;이석헌;권지향;안규홍
    • 상하수도학회지
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    • 제18권3호
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    • pp.377-384
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    • 2004
  • In the present study, a feasibility of an advanced oxidation process using UV/Hydrogen peroxide($H_2O_2$) system equipped with a medium pressure lamp for secondary effluent reclamation was investigated. Initial concentration of $H_2O_2$ and pH were changed to determine the optimum operation condition for the system. The removal efficiency of color was than 80% with 14.3mg/L of initial $H_2O_2$ and 5 minute of contact time in the UV/$H_2O_2$ system. The color removal was analyzed using first-order reaction equation. The dependence of rate constant (k) on initial $H_2O_2$ represented the rational relationship with maximum value. Residual $H_2O_2$ caused increase of effluent COD, since analyzing agent, dichromate, reacted with $H_2O_2$ in the sample. Therefore, excess initial concentration of $H_2O_2$ would significantly affect effluent COD measurement. At pH variation experiment, both residual $H_2O_2$ and color showed peak in the neutral pH range with the same pattern. Effect of $H_2O_2$ dose also enhanced color removal but raised residual $H_2O_2$ problem in the continuous operation UV system. In conclusion, these results indicated that medium pressure UV/$H_2O_2$ system could be used to control color in the secondary effluent for reclamation and reuse.

자궁절제 여성의 부담감에 관한 연구 (The Burden in Women with Hysterectomy)

  • 성미혜
    • 여성건강간호학회지
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    • 제3권2호
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    • pp.180-191
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    • 1997
  • When women are removed with their matrix which is a emotionally significant organ of symbol in psychologically adapting themselves to mother and woman, that is threatened and injured with woman role decisively. The nursing for women with hysterectomy is limited to medical treatment and the nursing related to troubles in psychology, emotion they experience in general situation due to operations is hardly realized. New basis for nursing can be realized when we both have relation with lived human experience related th health and become to be a part of it. We need to catch their experience due to the loss of matrix to understand women with hysterectomy. The subjects of the study were nine patients who were admitted to a gynecological ward of a hospital in Seoul, suffering from vaginal bleeding, back pain, abdominal pain and so on and diagnosing as non-cancer. The data were collected from April to May 1997 by listening to the subjects' expression of their experience and by participant observation of the subjects' reactions. A tape-recorder was used under the permission of the subjects, to prevent the loss of spoken information. The result of the study was as follows : The data on burden content from the interview were categorized as psych-emotional, physical, personal interaction, financial burden and maternal role burden. The factors which have influence on the burden of the subjects are an offer of information, support system, age, occupation, economic situation, family history, character, season, the existence of ovary and religion. In conclusion, since we ascertained that the nursing in the process of recovery decide the quality of life, though women with hysterectomy undergo various burden experience and adapt to it in the end, it is necessary to give them enough information and educate husband, having on important effect on the burden experience, to be a good supporter. And technically skilled nurses of consultant are thought to be able to contrive better qualitative life of women with hysterectomy as an important bridge between the subjects and their required information, since the nurses have their well-formed position of relationship of confidence through continuous contact with patients and their family.

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Cytocompatibility and cell proliferation evaluation of calcium phosphate-based root canal sealers

  • Mestieri, Leticia Boldrin;Zaccara, Ivana Maria;Pinheiro, Lucas Siqueira;Barletta, Fernando Branco;Kopper, Patricia Maria Polli;Grecca, Fabiana Soares
    • Restorative Dentistry and Endodontics
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    • 제45권1호
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    • pp.2.1-2.7
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    • 2020
  • Objectives: This study aimed to evaluate the cell viability and migration of Endosequence Bioceramic Root Canal Sealer (BC Sealer) compared to MTA Fillapex and AH Plus. Materials and Methods: BC Sealer, MTA Fillapex, and AH Plus were placed in contact with culture medium to obtain sealers extracts in dilution 1:1, 1:2 and 1:4. 3T3 cells were plated and exposed to the extracts. Cell viability and migration were assessed by 3-(4,5-dimethylthiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT) and Scratch assay, respectively. Data were analyzed by Kruskal-Wallis and Dunn's test (p < 0.05). Results: The MTT assay revealed greater cytotoxicity for AH Plus and MTA Fillapex at 1:1 dilution when compared to control (p < 0.05). At 1:2 and 1:4 dilutions, all sealers were similar to control (p > 0.05) and MTA Fillapex was more cytotoxic than BC Sealer (p < 0.05). Scratch assay demonstrated the continuous closure of the wound according to time. At 30 hours, the control group presented closure of the wound (p < 0.05). At 36 hours, only BC Sealer presented the closure when compared to AH Plus and MTA Fillapex (p < 0.05). At 42 hours, AH Plus and MTA Fillapex showed a wound healing (p > 0.05). Conclusions: All tested sealers demonstrated cell viability highlighting BC Sealer, which showed increased cell migration capacity suggesting that this sealer may achieve better tissue repair when compared to other tested sealers.

산왕거미 (Araneus ventricosus) 심관과 심근세포의 미세구조 (Fine Structure of the Heart Tube and Its Cardiac Muscle Cells in the Spider, Araneus ventricosus)

  • 최재영;문명진
    • Applied Microscopy
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    • 제33권4호
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    • pp.325-333
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    • 2003
  • 왕거미과 산왕거미(Araneus ventricosus)의 심관과 심근세포의 미세구조적 특성을 주사형 및 투과형 전자현미경으로 관찰하였다. 거미의 심관은 복부마디의 등쪽에 분포되어 있고, 심외막과 심근층으로 구성되어 있었다. 심근층의 근섬유들은 종축을 중심으로 나선상의 배열을 이루고 있었고, 내막이 없이 혈림프에 직접 노출되는 구조를 이루고 있었다. 심관의 외부 표면에서는 3쌍의 심문이 형성되어 있었고, 내강에서는 원형질혈구와 과립혈구, 그리고 편도혈구 등 다양한 유형의 혈구들이 관찰되었다. 특히 심관의 내강을 향해 돌출된 심근돌기 주위에서는 편도혈구들이 대부분을 차지하고 있었다. 편도혈구의 세포질에는 유리 리보조옴이 산재되어 있었고 핵에는 이질염색질과 인이 발달되어 있었으나, 심근층 조직과의 특이한 연접은 관찰되지 않았다. 심근층에는 횡문이 형성되어 있었고, Z-line을 중심으로 근절의 구조를 이룬 근원섬유의 주위에서는 미토콘드리아와 근소포체가 풍부하게 함유되어 있었다. 심관의 배면을 따라 뻗은 신경절의 축삭들이 심근세포와 신경근육간 연접부를 형성하고 있음이 관찰되었다.

개량형 가동보에 적용하기 위한 패널형 유리섬유보강 폴리머 복합재료 클램핑 플레이트의 환경노출 성능 (Environmental Exposure Performance of a Panel-Type Glass-Fiber-Reinforced Polymer Composite Clamping Plate for an Improved Moveable Weir)

  • 유성열;전종찬;신형진;박찬기
    • 한국농공학회논문집
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    • 제59권5호
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    • pp.73-81
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    • 2017
  • The improved movable weir supplements the advantages and disadvantages of the rubber weir and the conduction gate. It consists of a stainless steel gate, air bags, and a steel clamping plate. The stainless steel gate is the main body of the weir, and the inflatable rubber sheet serves to support the steel gate. The steel clamping plate is typically in direct continuous contact with water, but this leads to corrosion issues that can reduce the life of the entire movable weir. In this study, a panel-type glass-fiber-reinforced polymer (GFRP) clamping plate was designed and fabricated. The test results showed that the flexural load of the panel-type GFRP composite clamping plate was over twice that of the wings type GFRP clamping plate. The lowest moisture absorption value was obtained upon exposure to tap water, and exposure to other solutions showed similar values. Additionally, flexural load testing after exposure to an accelerated environment found the lowest residual loads of 80.51 % and 78.50 % at 50 and 100 days, respectively, for exposure to a $CaCl_2$ solution, while exposure to other environments showed residual failure loads of over 80 % at both 50 and 100 days.

연성포장의 3차원 유한요소해석을 위한 최적 경계조건 분석 (Appropriate Boundary Conditions for Three Dimensional Finite Element Implicit Dynamic Analysis of Flexible Pavement)

  • 유평준;;김연복
    • 한국도로학회논문집
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    • 제10권4호
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    • pp.213-224
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    • 2008
  • 트럭 축하중에 의한 도로포장체의 응력과 변형은 대부분 다층 탄성 이론에 의해 예측된다. 대부분의 다층 탄성 이론에 의한 이론적 계산값이 연성 포장 재료의 점탄성적 거동특성, 동적 트럭 축하중, 비균등 타이어 접지압 및 형상등을 해석에 고려하지 못하므로, 계측값에 비해 매우 작은 값을 예측하므로서 도로 포장 두께설계가 과소 설계될 우려가 크다. 이와 같은 도로 포장체 구조해석시 이용되는 중요한 변동요소를 포장 재료의 물성 모델 측면, 비균등 접지압 및 형상 측면, 동적 유한요소해석 측면에서 분석하여 이용 가능한 모델을 본 논문에서 제안하였다. 경계조건 및 민감도 분석을 수행을 통한 효과적인 3차원 연성포장의 유한요소해석모델을 결정하는 방법론을 제안하였으며, 최적 유한요소모델 분석결과와 현장에서 취득한 결과와의 상호비교를 통하여 모델의 유의성을 검증하였으며, 동적 접지하중조건, 점탄성물성 모델 등을 3차원 유한요소 모델에 접목하고, 최적 경계조건을 결정하였다.

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