• 제목/요약/키워드: Time Effects

검색결과 21,153건 처리시간 0.04초

모과 추출물의 항응혈 활성 (Active Effect of Antivoagulant Effects in chaenomelis Fructus Water Extract)

  • 유지현;한신희;길기정
    • 대한본초학회지
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    • 제24권2호
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    • pp.7-11
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    • 2009
  • Objectives : This research was investigated anticoagulant effect of the Chaenomelis Fructus extract. Methods : To examine an active effect of anticoagulation in Chaenomelis Fructus extract, the study measured Prothrombin time(PT) and activated partial thromboplastin time (APTT) of human plasma in vitro and measured bleeding time and arterio-venous shunt model in rats in vivo. Results : Bleeding time of Chaenomelis Fructus extract in vivo had a significant increase as about 1.6 times and thrombus weight of Chaenomelis Fructus extract had a significant reduction of thrombus weight as 50%. Chaenomelis Fructus extract represented an effect of anticoagulation by operating on extrinsic pathway factor II, V, VII, X and intrinsic pathway factor VIII, IX, X, XI, XII in the coagulation system. Conclusions : Considering the above mentioned results, it is judged that a Chaenomelis Fructus extract has a control effect of thrombus creation.

Time-Delay Effects on DC Characteristics of Peak Current Controlled Power LED Drivers

  • Jung, Young-Seok;Kim, Marn-Go
    • Journal of Power Electronics
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    • 제12권5호
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    • pp.715-722
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    • 2012
  • New discrete time domain models for the peak current controlled (PCC) power LED drivers in continuous conduction mode include for the first time the effects of the time delay in the pulse-width-modulator. Realistic amounts of time delay are found to have significant effects on the average output LED current and on the critical inductor value at the boundary between the two conduction modes. Especially, the time delay can provide an accurate LED current for the PCC buck converter with a wide input voltage. The models can also predict the critical inductor value at the mode boundary as functions of the input voltage and the time delay. The overshoot of the peak inductor current due to the time delay results in the increase of the average output current and the reduction of the critical inductor value at the mode boundary in all converters. Experimental results are presented for the PCC buck LED driver with constant-frequency controller.

Time-dependent effects on dynamic properties of cable-stayed bridges

  • Au, Francis T.K.;Si, X.T.
    • Structural Engineering and Mechanics
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    • 제41권1호
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    • pp.139-155
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    • 2012
  • Structural health monitoring systems are often installed on bridges to provide assessments of the need for structural maintenance and repair. Damage or deterioration may be detected by observation of changes in bridge characteristics evaluated from measured structural responses. However, construction materials such as concrete and steel cables exhibit certain time-dependent behaviour, which also results in changes in structural characteristics. If these are not accounted for properly, false alarms may arise. This paper proposes a systematic and efficient method to study the time-dependent effects on the dynamic properties of cable-stayed bridges. After establishing the finite element model of a cable-stayed bridge taking into account geometric nonlinearities and time-dependent behaviour, long-term time-dependent analysis is carried out by time integration. Then the dynamic properties of the bridge after a certain period can be obtained. The effects of time-dependent behaviour of construction materials on the dynamic properties of typical cable-stayed bridges are investigated in detail.

Creep and shrinkage effects in service stresses of concrete cable-stayed bridges

  • Lozano-Galant, Jose Antonio;Turmo, Jose
    • Computers and Concrete
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    • 제13권4호
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    • pp.483-499
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    • 2014
  • Most of the methods presented in the literature to define the target service stresses (Objective Service Stage, OSS) of cable-stayed bridges rarely include the time-dependent phenomena effects. Nevertheless, especially in concrete structures, this assumption might be on the unsafe side because time-dependent phenomena usually modify service stresses. To fill this gap, this paper studies the time-dependent phenomena effects into service stresses of concrete cable-stayed bridges. After illustrating the important role of these phenomena in an asymmetrical cable-stayed bridge without backstay, a new method to include their effects into the OSS is presented. An important issue to be considered in this method is the target time in which the OSS is defined to be achieved. The application of this method to two different structures showed the convenience of defining the OSS to be achieved at early times because that way the envelope of service stresses is reduced.

Effects of Cranial Electrotherapy Stimulation on Electrocephalogram

  • Lee, Jeongwoo;Lee, Hyejein;Park, Woongsik
    • 국제물리치료학회지
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    • 제10권1호
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    • pp.1687-1694
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    • 2019
  • Background: Although cranial electrotherapy stimulation (CES) is reported to have positive effects on mental functions such as depression and sleep improvement, detailed studies regarding awakening, attention and concentration among brain waves reflecting brain activity are lacking. Objective: To examine the effects of cranial electrotherapy stimulation (CES) on various electroencephalograms (EEGs) reflecting brain activities. Design: Randomized controlled clinical trial (single blind) Methods: This study selected 30 healthy adult women in their 20s who volunteered for this experiment. A total of 30 subjects were randomly assigned to three groups (Sham group, 0.5 Hz CES group, and 100 Hz CES group). EEGs were measured before and after the single CES, and the results were compared and analyzed. Results: The relative theta, alpha, and gamma waves indicated no significant differences in the interaction effects between time and group. The relative fast alpha wave only showed significant differences in the interaction effects between time and group in P4. The relative slow beta wave only indicated statistically significant differences in the interaction effects between time and group in T3 and T4. The relative mid and fast beta waves showed statistically significant differences in the interaction effects between time and group in all areas. Conclusions: These results suggest that a CES of 0.5 Hz awakens consciousness and has a positive influence on brain activity, while a CES of 100 Hz has a positive influence on thinking activity accompanying mental load during concentrating on one subject.

Time-Delay Effects on DC Characteristics of Peak Current Controlled Power LED Drivers

  • Kim, Marn-Go;Jung, Young-Seok
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2011년도 전력전자학술대회
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    • pp.481-482
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    • 2011
  • New discrete time domain models for the peak current controlled (PCC) power LED drivers in continuous conduction mode include for the first time the effects of time delay in the pulse-width-modulator. Realistic amounts of time delay are found to have significant effects on the average output LED current and on the critical inductor value at the boundary between two conduction modes. Especially, the time delay can provide an accurate LED current for the PCC buck converter with a wide input voltage. The models can also predict the critical inductor values at the mode boundary as functions of the input voltage and the time delay.

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Effects of Cooking Time and HTST Air Dehydration Time on Physical Propertiesof Driet Green Peas

  • 김명환
    • 한국식품영양과학회지
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    • 제19권3호
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    • pp.195-200
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    • 1990
  • Effects of cooking time(5-30 min in a pressure cooker) and HTST air dehydratiion time(0-9min at 15$0^{\circ}C$) on physical properties of dried green peas(3% oisture content wet basis) were investigated by determining rehydration ratio rehydration curve browning reaction and puncture force, The rehydration ratio and curve of dried green peas were increased with increa-sing cooking time and HTST air dehydration time. Preheating of the green peas for 30 min in a pressure cooker or for 9 min of HTST air dehydration time prior to 6$0^{\circ}C$ air dehydration recovered a 87.3% of original moisture content of raw green peas in a boiling water for 5 min. The brownin greaction was gradually decreased up to 15 min of cooking time. Puncture pressure of rehydrated green peas treated in a boiling water for 5 min was decreased as the cooking time and HTST air dehydration time were increased and was highly correlated with rehydration (r=-0.956) The effects of cooking time and HTST air dehydration time on rehydration ratio browning reaction and puncture pressure were significantly different at the a=0.01 level except effect of HTST air dehydration time on browning reaction.

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PCS 합성거더교의 시간에 따른 응력 변화 추정 (Estimation of Stress Variations on Time Effects in Prestressed Concrete Composite Girder Bridges)

  • 윤지훈;김수만
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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    • pp.319-322
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    • 2005
  • When a concrete structure is subjected to load, its response is both immediate and time dependent. Under sustained load, the deformation of a structure gradually increases with time and eventually may be many time greater than its instantanneous value. The gradual development of strain with time is caused by creep and shrinkage. On this study, to estimate of stress variations on time effects in partially prestressed concrete composite girder bridges, computer program applied Age-adjusted Effective Modulus Method(AEMM) in used.

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심폐소생술 재교육이 간호사의 지식과 기술에 미치는 지속효과 (A Study on the Sustainable Effects of Reeducation on Cardiopulmonary Resuscitation on Nurses' Knowledge and Skills)

  • 오수일;한상숙
    • 대한간호학회지
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    • 제38권3호
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    • pp.383-392
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    • 2008
  • Purpose: This study was to analyze the sustainable effects of cardiopulmonary resuscitation (CPR) reeducation on nurses' knowledge and skills. Methods: A repeated experimental design was used for a single sample group of 47 nurses working for a general hospital. The nurses were tested on their skill of CPR 3 times at an interval of 4 m1onths. In order to test nurses' knowledge and skills, the researcher used a CPR assessment program linked to an adult practice doll (Anne). Results: 1) The amount of decrease of nurses' knowledge about CPR between points of time was wide between first and second points of time but small between the second and third time owing to the effects of reeducation between the two points of time. 2) Nurses' skills between the first and second time dropped but they improved between the second and third time owing to the effects of reeducation. Conclusion: As confirmed by the above findings, reeducation of CPR clearly affects nurses' knowledge and skills. Given the fact that the same period of time (4 months) elapsed between the 3 tests, it could be argued that the reeducation at the second test served to maintain nurses' knowledge and enhance their skills.