• 제목/요약/키워드: stress recovery

검색결과 659건 처리시간 0.032초

Adaptive Responses of Escherichia coli for Oxidative and Protein Damage Using Bioluminescence Reporters

  • Min, Ji-Ho;Gu, Man-Bock
    • Journal of Microbiology and Biotechnology
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    • 제14권3호
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    • pp.466-469
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    • 2004
  • The recombinant bioluminescent Escherichia coli strains, DPD2511 and TV 1061 containing the katG and grpE promoters, respectively, from Vibrio fischeri fused to luxCDABE, were used to detect the adaptive and repair responses to oxidative damage caused by hydrogen peroxide $(H_2O_2)$, and protein damage due to phenol. The response ratio, represented as the bioluminescence induced in subsequent inductions of DPD2511 and TV1061 with the mother cells previously induced by each chemical, i.e., $H_2O_2$ and phenol during the previous induction stage, decreased suddenly compared with the ratio of the control culture of each strain, meaning there is a possible adaptive response to stress caused by chemicals. Protein damage due to phenol was completely repaired by the second culturing after the initial induction, as was oxidative damage caused by $H_2O_2$ which was also rapidly repaired, as detected by the recovery of bioluminescence level. This result suggests that E. coli promptly adapt and repair oxidative and protein damage by $H_2O_2$ and phenol completely.

전기이중층커패시터의 가속열화시험 (An Accelerated Degradation Test of Electric Double-Layer Capacitors)

  • 정재한;김명수
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제12권2호
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    • pp.67-78
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    • 2012
  • An electric double-layer capacitor(EDLC) is an electrochemical capacitor with relatively high energy density, typically hundreds of times greater than conventional electrolytic capacitors. EDLCs are widely used for energy storage rather than as general-purpose circuit components. They have a variety of commercial applications, notably in energy smoothing and momentary-load devices, and energy-storage and kinetic energy recovery system devices used in vehicles, etc. This paper presents an accelerated degradation test of an EDLC with rated voltage 2.7V, capacitance 100F, and usage temperature $-40^{\circ}C{\sim}65^{\circ}C$. The EDLCs are tested at $50^{\circ}C$, $60^{\circ}C$, and $70^{\circ}C$, respectively for 1,750hours, and their capacitances are measured at predetermined times by constant current discharge method. The failure times are predicted from their capacitance deterioration patterns, where the failure is defined as 30% capacitance decrease from the initial one. It is assumed that the lifetime distribution of EDLC follows Weibull and Arrhenius life-stress relationship holds. The life-stress relationship, acceleration factor, and $B_{10}$ life at design condition are estimated by analyzing the accelerated life test data.

Dilatation characteristics of the coals with outburst proneness under cyclic loading conditions and the relevant applications

  • Li, Yangyang;Zhang, Shichuan;Zhang, Baoliang
    • Geomechanics and Engineering
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    • 제14권5호
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    • pp.459-466
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    • 2018
  • By conducting uniaxial loading cycle tests on the coal rock with outburst proneness, the dilatation characteristics at different loading rates were investigated. Under uniaxial loading and unloading, the lateral deformation of coal rock increased obviously before failure, leading to coal dilatation. Moreover, the post-unloading recovery of the lateral deformation was rather small, suggesting the onset of an accelerated failure. As the loading rate increased further, the ratio of the stress at the dilatation critical point to peak-intensity increased gradually, and the pre-peak volumetric deformation decreased with more severe post-peak damage. Based on the laboratory test results, the lateral deformation of the coals at different depths in the #1302 isolated coal pillars, Yangcheng Coal Mine, was monitored using wall rock displacement meter. The field monitoring result indicates that the coal lateral displacement went through various distinct stages: the lateral displacement of the coals at the depth of 2-6 m went through an "initial increase-stabilize-step up-plateau" series. When the coal wall of the working face was 24-18 m away from the measuring point, the coals in this region entered the accelerated failure stage; as the working face continued advancing, the lateral displacement of the coals at the depth over 6 m increased steadily, i.e., the coals in this region were in the stable failure stage.

피로균열진전에 따른 304 강의 음향방출 거동 (Acoustic emission behavior during fatigue crack propagation in 304 Stainless steel)

  • 오광환;정창규;양유창;한경섭
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.213-219
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    • 2003
  • Acoustic emission behavior during fatigue crack growth test was investigated under various loading condition. To describe the acoustic emission activity, counts rate (d/dn) was related with SIFR (stress intensity factor range, K). Results indicated that SIFR could be divided into two parts according to its relationship with counts rate. For $K<25_{MPa\sqrt{m}}$, counts rate was increased as the SIFR increased. However, for values greater than $25_{MPa\sqrt{m}}$ , decreasing behavior was shown. This behavior of counts rate corresponding SIFR was keeping the same trend regardless of load range or crack length. Acoustic emission response to the single overload was sudden drop and slow recovery in counts rate like crack growth retardation. Under variable loading condition, counts rate of each loading block was same as that of constant amplitude loading. Overall experimental data was somewhat scattered since sensitive characteristics of acoustic emission method. However, these empirical relations indicated that counts rate was uniquely correlate with single parameter, SIFR.

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화병 임상진료지침 II. (화병의 실태) (Clinical Guidelines for Hwabyung II. (Research on the Status of Hwabyung in Korea))

  • 정선용;송승연;김종우
    • 동의신경정신과학회지
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    • 제24권spc1호
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    • pp.15-22
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    • 2013
  • Objectives : The Hwabyung Research Center of The Korean Society Of Oriental Neuropsychiatry attempted to produce clinical guidelines for doctors of Korean medicine for the treatment of Hwabyung. Methods : A standard guideline development process was followed. Relevant literature was identified by a review of bibliographies. The operational criteria were used to rate the quality of scientific evidence, and the line of treatment recommendations included a consensus clinical opinion. This section of "the status of Hwabyung in Korea" is 2 out of 5 articles drafted and reviewed by clinicians. Results : Hwabyung is changed depending on the time and have a risk of relapse. Like the previous studies, Female and lower socio-economic and educational level people suffers Hwabyung frequently. But recently number of Male Hwabyung patients increases. Recovery of Hwabyung is involved in depression, anxiety, stress. Hwabyung is related to Major depressive disorder, generalized anxiety disorder, somatoform disorder and diseases of the digestive system. Conclusions : This study was observed for the progression of Hwabyung. Hwabyung is a long-term disease associated with depression, anxiety and stress. Hwabyung is accompanied by physical and psychological symptoms and degrades the quality of life.

Highly Sensitive Tactile Sensor Using Single Layer Graphene

  • Jung, Hyojin;Kim, Youngjun;Jin, Hyungki;Chun, Sungwoo;Park, Wanjun
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.229.1-229.1
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    • 2014
  • Tactile sensors have widely been researched in the areas of electronics, robotic system and medical tools for extending to the form of bio inspired devices that generate feeling of touch mimicking those of humans. Recent efforts in adapting the tactile sensor have included the use of novel materials with both scalability and high sensitivity [1]. Graphene, a 2-D allotrope of carbon, is a prospective candidate for sensor technology, having strong mechanical properties [2] and flexibility, including recovery from mechanical stress. In addition, its truly 2-D nature allows the formation of continuous films that are intrinsically useful for realizing sensing functions. However, very few investigations have been carrier out to investigate sensing characteristics as a device form with the graphene subjected to strain/stress and pressure effects. In this study, we present a sensor of vertical forces based on single-layer graphene, with a working range that corresponds to the pressure of a gentle touch that can be perceived by humans. In spite of the low gauge factor that arises from the intrinsic electromechanical character of single-layer graphene, we achieve a resistance variation of about 30% in response to an applied vertical pressure of 5 kPa by introducing a pressure-amplifying structure in the sensor. In addition, we demonstrate a method to enhance the sensitivity of the sensor by applying resistive single-layer graphene.

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A Novel High Step-Up Converter with a Switched-Coupled-Inductor-Capacitor Structure for Sustainable Energy Systems

  • Liu, Hongchen;Ai, Jian;Li, Fei
    • Journal of Power Electronics
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    • 제16권2호
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    • pp.436-446
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    • 2016
  • A novel step-up DC-DC converter with a switched-coupled-inductor-capacitor (SCIC) which successfully integrates three-winding coupled inductors and switched-capacitor techniques is proposed in this paper. The primary side of the coupled inductors for the SCIC is charged by the input source, and the capacitors are charged in parallel and discharged in series by the secondary windings of the coupled inductor to achieve a high step-up voltage gain with an appropriate duty ratio. In addition, the passive lossless clamped circuits recycle the leakage energy and reduce the voltage stress on the main switch effectively, and the reverse-recovery problem of the diodes is alleviated by the leakage inductor. Thus, the efficiency can be improved. The operating principle and steady-state analyses of the converter are discussed in detail. Finally, a prototype circuit at a 50 kHz switching frequency with a 20-V input voltage, a 200-V output voltage, and a 200-W output power is built in the laboratory to verify the performance of the proposed converter.

오미자를 이용한 스포츠 드링크 섭취가 혈액성분과 운동수행력 및 HSP70에 미치는 영향 (The Effect of Sports Drink Containing Schizandra Chinensis on Blood Biochemical Elements, Exercise Performance and HSP70)

  • 오재근;김복주;신영오;정희정
    • 대한한의학회지
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    • 제23권2호
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    • pp.139-150
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    • 2002
  • OBJECTIVES : Schizandra chinensis is well known for its efficacy at liver function reinforcement, relieving thirst and recovery from fatigue. In this study, we examined the effects of sports drink containing Schizandra chinensis on serum metabolic substrate, electrolyte, stress indicators, related-enzyme and exercise performance, rectal temperature, and heat shock proteinb70 (HSP70). METHODS : Elite long-distance runners (male, 21.3yrs, n=16) were selected and divided into two groups; an experimental group (EXP, n=8) and a control group (CON, n=8). A beverage containing Schizandra chinensis was supplemented 3 times per day to EXP for 4 weeks. Serum biochemical elements (glucose, lactate, total cholesterol, triglyceride, high density lipoprotein cholesterol, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, creatinine, creatine phosphokinase, lactate dehydrogenase, blood urea nitrogen, Na, K, Cl) were analyzed by auto blood analyzer. Exercise performance was measured by treadmill exercise test, HSP70 was detected by electrophoresis and Western blotting, and rectal temperature was measured by rectal temperature probe. RESULTS : Administration of the beverage increased significantly the rest level of blood Na, Cl and glucose and decreased significantly lactate dehydrogenase, glutamate oxaloacetate transaminase. No difference was found in exercise performance, rectal temperature increment or HSP70 concentration between groups. CONCLUSIONS : Administration of a sports drink containing Schizandra chinensis altered blood glucose, lactate dehydrogenase, glutamate oxaloacetate transaminase, Na and Cl levels.

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이방성 보 구조물 응력해석에서의 생브낭 원리 (Application of Saint-Venant's Principle to Anisotropic Beams)

  • 김준식
    • 대한기계학회논문집A
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    • 제36권4호
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    • pp.451-455
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    • 2012
  • 수학적 방법에 기초한 점근해석기법은 이방성 보 구조물의 설계 및 해석에 있어 강력한 도구이다. 이러한 장점에도 불구하고, 점근해석 기법은 전단 변형에 상대적으로 취약한 복합재료 보의 고차해를 구함에 있어 점근적으로 정확한 경계조건을 필요로 한다. 생브낭의 원리를 적용하여 응력상태를 개선하는 방법은 등방성 보 및 판 구조물에 대하여 개발되었고, 외팔보 등의 예제를 통해 검증되었다. 이 방법은 점근적으로 정확한 경계조건을 요구하지 않으며, 반복계산도 필요로 하지 않는다는 장점이 있다. 본 논문에서는 이 방법을 일반 이방성 보 구조물에 대하여 확장 적용하여 생브낭의 원리를 적용하는 방법을 일반화 하고자 한다.

노인주거복지 향상을 위한 의료서비스 지원방안 연구 - Aging in Place 개념을 중심으로 - (Medical Treatment Service for the Housing Welfare of Elderly People- Laying stress on Aging in Place concept -)

  • 이준민;박남희;신화경
    • 한국주거학회:학술대회논문집
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    • 한국주거학회 2005년도 추계학술대회 논문집
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    • pp.367-370
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    • 2005
  • Offer of medical treatment service for recovery or preservation of physical spiritual function of elderly people by sudden population graying developing is essential. Therefore, according to increase of elderly's medical treatment demand, medical treatment service request is augmented. Number of medical treatment service utilization wishes to grope medical treatment service support way for elderly residing cloth elevation laying stress on elderly's Aging in Place in increase trend in this research. If decide, is as following : First, national hospital and public health center were concentrated most on Seoul and kyonggi, and there were many hospitals to south of a river nine, Songpagu, Seochogu, and public health center was expose that is one by one to each nine. Second, in the case of Seoul, elderly population ratio was expose that comparatively high Yeongdeungpo, Chongno, Yongsan, west passage nine is few hospital number relatively in elderly's residential area. Third, need that establish elderly full text clinic on part of general hospital or university hospital equipment. Fourth, must do so that can use access as is easy little more in local community to all elderly who need medical treatment service of visit nursing, visit medical examination and treatment etc.. that consist in present public health center.

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