• 한국음향학회지
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• 제23권5호
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• pp.340-352
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• 2004

28.5 ㎑의 초음파의 미세 수직진동에 의해서 유도된 음향유동 (acoustic streaming)을 레이저를 이용한 입자 영상. 유속계에 의하여 고정 유리 평판과 초음파 진동자의 사이에서의 공기 유동을 가시화 하였다. 음향유동에 의한 공기의 유동 속도의 증가를 측정하기 위해 고정 유리 평판과 초음파 진동자의 사이에서의 속도변화를 실시간으로 측정하였다. 진동자와 고정 평판의 사이의 gap에 따른 음향유동의 세기의 변화를 정량적인 공기의 유동 속도의 변화에 의해 관찰되었고 고정판과 초음파 진동자 사이의 gap에서 공진 상태를 야기시키는 공진 Gap (H=18, 24, 30, 36㎜)중에서 공진 Gap (H)이 18m일 때 최대의 음향속도가 존재함을 알 수 있었고 진동자 표면부근에서부터 고정평판사이까지의 국소 최대 난류강도의 축 방향 위치에 따른 변화는 gap의 크기에 따라 8%∼70% 이었다. 전단응력값은 반경방향 위치의 중심영역에서 최대전단응력을 가지며 와도 분포도 반경방향 위치에서 진동자 중심영역에 최대 및 최소와도 값을 가짐을 알 수 있었다.

• Journal of Yeungnam Medical Science
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• 제17권1호
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• pp.12-20
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• 2000

The memory of pain can be more damaging than its initial experience. Several factors arc related the directions of pain memory: current pain intensity, emotion, expectation of pain, and peak intensity of previous pain. The possible mechanisms behind the memory of pain are neuroplastic changes of nervous system via peripheral and central sensitization. Peripheral sensitization is induced by neurohumoral alterations at the site of injury and nearby. Biochemicals such as K+, prostaglandins, bradykinin, substance P, histamine and serotonin, increase transduction and produce continuous nociceptive input. Central sensitization takes place within the dorsal horn of spinal cord and amplifies the nociceptive input from the periphery. The mechanisms of central sensitization involve a variety of transmitters and postsynaptic mechanisms resulting from the activations of NMDA receptors by glutamate. and activation of NK-1 tachykinnin receptors by substance-P and neurokinnin. The clinical result of peripheral and central sensitization is hyperalgesia, allodynia, spontaneous pain, referred pain, or sympathetically maintained pain. These persistent sensory responses to noxious stimuli arc a form of memory. The hypothesis of preemptive analgesia is that analgesia administered before the painful stimulus will prevent or reduce subsequent pain and analgesic requirements in comparison to the identical analgesic intervention administered after the painful stimulus, by preventing or reducing the memory of pain in the nervous system. Conventionally, pain management was initiated following noxious stimuli such as surgery. More recently, however many have endorsed preemptive analgesia initiated before surgery. Treatments to control postsurgical pain are often best started before injury activates peripheral nociceptors and triggers central sensitization. Such preemption is not achieved solely by regional anesthesia and drug therapy but also requires behavioral interventions to decrease anxiety or stress. Although the benefit of preemptive analgesia may not be obvious in every circumstance, and in many cases may not sufficient to abolish central sensitization, it is an appropriate and human goal of clinical practice.

• 대한기계학회논문집B
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• 제25권10호
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• pp.1417-1426
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• 2001

Turbulent flow characteristics in the near wake of a square cylinder have been studied experimentally by using a Digital PIV method. Experiments are performed at the Reynolds numbers of 1600 and 3900 based on the free-stream velocity and the square height. The ensemble averaged turbulence statistics are acquired from 2030 realizations of instantaneous fluctuating velocity field after the conventional Reynolds decomposition. The differences in turbulent intensity and Reynolds shear stress profiles fur both oases indicate that the effect of Reynolds number seems to be descernible mainly due to the occurrence of transition in the separated shear layer. Because of the periodic nature of vortex shedding process, transverse velocity fluctuations contribute dominantly , to turbulent kinetic energy distribution. A comparison with previous LDV data obtained at much higher Reynolds number shows a fairly good agreement each other. It turns out that the effect of Reynolds number diminishes as increasing Reynolds number, which is a well-known feature of a sharp-edged bluff body wake. The streamwise variation of turbulence intensities are compared with those from a circular cylinder along the centerline at the same Reynolds number. The overall magnitudes and the decay rates of turbulence intensities are quite similar, but some differences are noticeble especially in the transverse intensity variation.

• 대한기계학회논문집
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• 제16권9호
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• pp.1788-1795
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• 1992

본 연구에서는 상술한 특성을 갖는 유동자에 대하여 신뢰성이 보장된 스펙트 럼 추정법의 모색과 화립을 위해 의사 난류신호(turbulent-like signal)를 자기회기 모형(autoregressive model:AR model)으로 생성하고 추출간격이 유동장에 영향을 받는 비주기적 확률과정을 수치적으로 모사한다. 이 비주기적 실현 신호로 부터 현재 가 장 많이 사용되고 있는 Roberts와 Gaster의 직접 변화법과 추출 및 유지신호의 피리오 도그램(periodogram)법에 대해 데이터 밀도와 난류강도의 다양한 변화에 따른 속도편 의의 영향 등을 살펴보는데 목적을 둔다.

• Design & Manufacturing
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• 제10권1호
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• pp.19-25
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• 2016

Connectors are very important components that transmit electric signals to different parts. It must maintain intensity of the connector to prevent defects from impact and maintain contact to transmit electric signals. Most of the external parts of the connector, which act as the main framework, are formed by injection molding. However, bend deformation occurs for injection molded products due to the residual stress left inside the product after product molding. When the bend deformation is large, it does not come into complete contact when being assembled with other parts, which leads to connector contact intensity not being properly maintained. In result, the main role of the connector, which is to transmit electric signals, cannot be performed. In order to address this problem, this study conducted bend deformation cause analysis through bend deformation analysis to predict and prevent bend deformation of housings and wafers, which are injection molded products of pressure welded connectors that are normally applied in compact mobile and display products. Bend deformation analysis was carried out by checking the charging time, pressure distribution and temperature distribution through wire to board connector wafer and housing injection molding analysis. Based on the results of the bend deformation analysis results, the cause of the bend deformation was analyzed through deformation resulting from disproportional cooling, deformation resulting from disproportional contraction, and deformation resulting from ingredient orientation. In result, it was judged that the effects for bend deformation were biggest due to disproportional contraction for both the pressure welded connector wafer and housing.

• 여성건강간호학회지
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• 제9권2호
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• pp.128-137
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• 2003

The purpose of this study was to identify effects of the SP-6 acupressure on dysmenorrhea, skin temperature at th e CV2 acupoint. This study was a pretest-post test study design wit h a nonequivalent control group. Data were collected from May 1 to August 31, 2002. A total of 58 female student s from two universities participated in the study. Among them, 30 female students were assigned as the experimental group an d the other 28 students to the control group. Both groups were pretested before the intervention for three variables, the degree of dysmenorrhea, and skin temperature at the CV2 acupoint. Then, the SP-6 acupressure was provided for 20 minutes for students in the experimental group. The instruments used in this study included the Visual Analogue Scale developed by Johnson(1974), skin thermometer by Simson Eectric CO., Menstrual Attitudes Questionnaire Scale developed by Brooks-Gunn & Ruble(1980), and Stress scale developed by Chun and Kim(1990). The data were analyzed with the SAS program using Chi-square test, t-test, and ANCOVA and Bonferroni method were used to determine significant differences between the two groups. The results of this study are as follows ; 1. There was a statistically significant difference in the intensity of dysmenorrhea after the intervention with the experimental group having a lower intensity than the control group. 2. There was a statistically significant difference in skin temperature at the CV2 acupoint 30min (F=4.87, p=0.03) after the intervention with the experimental group having a higher temperature. In conclusion, the SP-6 acupressure has proved to be an effective nursing intervention to reduce dysmenorrhea. Therefore, it is recommended women suffering from dysmenorrhea use the SP-6 acupressure.

• 한국약용작물학회지
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• 제18권2호
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• pp.65-69
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• 2010

As cool-season plant, Panax ginseng C. A. Meyer is planted under shade-installation with tall front and low rear. However, at different planting positions, distinct differences come out because ginseng grows at the same position within 3~5 years and the growth circumstance changes a lot by the shade-installation. So, in this study, changes of temperature, photosynthesis and chlorophyll fluorescence with varieties of shading material and planting position were investigated. Light transmittances by polyethylene shade net and silver-coated shading plate as planting materials were measured according to different planting positions. Photosynthetic rate and chlorophyll fluorescence were measured by LI-6400-40 (Li-Cor). According to different planting positions, light intensity was higher in silver-coated shading plate than in polyethylene shade net, and higher at front than rear. Also, photosynthetic rate showed the same tendency, which had a positive correlation to light intensity. But this treatment caused a lower Fo compared with polyethylene shade net because of the stress by light and temperature. Also, Fv/Fm and ETR were higher in silver-coated shading plate. Fo was similar at front and rear according to silver-coated shading plate and ETR was higher at front.

• 한국토양비료학회지
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• 제50권6호
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• pp.674-683
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• 2017

The frequency and intensity of soil moisture stress associated with climate change has increasing, and the stability of field crop cultivation has decreasing. This experiment was conducted to investigate the effect of soil moisture management method on growth and yield of corn. Soil moisture was managed at the grade of WSM (wet soil moisture, 34.0~42.9%), OSM (optimum soil moisture, 27.8~34.0%), DSM (dry soil moisture, 20.3~27.8%), and ESM (extreme dry moisture, 16.6~20.3%) during V8 (8th leaf stage)-VT (tasseling stage). After VT, irrigation was limited. The treated amount of irrigation was 54.1, 47.7, 44.0 and 34.5% of total water requirement, respectively. The potential evapotranspiration during the growing period was $3.29mm\;day^{-1}$, and upward movement of soil water was estimated by the AFKAE 0.5 model in the order of ESM, DSM, OSM, and WSM. We could confirm this phenomenon from actual observations. There was no significant difference in leaf characteristics, dry matter, and primary productivity depending on the level of soil moisture, but leaf development was delayed and dry weight decreased in DSM. However, dry weight and individual productivity of DSM increased after irrigation withdrawal compared to that of OSM. In DSM, ear yield and number of kernels per ear decreased, but water use efficiency and harvest index were higher than other treatments. Therefore, it is considered that the soil moisture is concentratedly managed before the V8 period, the V8-VT period is controlled within the range of 100 to 500 kPa (20.3~27.8%), and no additional irrigation is required after the VT.

• Journal of Ginseng Research
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• 제46권4호
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• pp.543-549
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• 2022

Background: In physical activity or labor, the human body is in a state of high intensity stress, and all parts or physiological functions of the body respond positively to maintain or balance the need for movement. The human body has many physiological changes in the process of movement, and fatigue is the external manifestation of various complex changes inside the human body. Fatigue is also a physiological mechanism of self-protection after the body reaches a certain level of activity, which can prevent the occurrence of life-threatening excessive functional failure. The generation of fatigue is a very complex process, and its mechanism has not been concluded yet. Therefore, it is an important work to search and screen the effective components of natural plants that have anti-fatigue effect and to explore their mechanism. Methods: This was a 8-week, randomized, double-blind, placebo-controlled clinical trial. A total of 110 subjects who passed physical examination were included according to the scheme design, and randomly divided into a test group which was given KRG and a placebo control group. The calculation is carried out according to the standard of sub-high-intensity exercise test. Results: There was no adverse effect on safety index of subjects after taking red ginseng capsule. After KRG treatment, subjective strength grade is significant lower than placebo treatment. Blood lactic acid content is significantly get lower after trial in KRG group, and significant lower than placebo group. Creatine phosphokinase(CK) content is significantly get lower after trial in KRG group, and significant lower than placebo group. Conclusion: According to the criterion in the test scheme, the result shows that KRG is helpful on relieving physical fatigue.

• 한국정보전자통신기술학회논문지
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• 제17권3호
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• pp.155-165
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• 2024

환원된 산화 그래핀(rGO)을 알루미늄, 티타늄, 스트론튬이 혼합된 졸-겔 용액에 혼합하여 브러시 코팅법을 이용하여 액정배향용 하이브리드 박막을 제조하였다. 160, 260, 및 360℃에서 어닐링한 후 산화 반응의 차이를 관찰하였다. 박막 제조 과정에서 생성된 졸-겔 용액은 브러시 모의 전단 응력에 의해 수축력을 발생시켜 미세홈 구조를 형성하였다. 이러한 구조는 주사 전자 현미경 분석을 통해 확인되었으며, rGO의 존재가 명확하게 보였다. 어닐링 온도가 증가함에 따라서 박막 표면의 산화 및 환원 반응이 더욱 활성화되어 표면 혼합물의 강도가 증가하였다. 또한 혼합물의 강도를 증가시킴으로써 전기광학적 특성이 안정화되고 개선되었다. 더불어 전압-정전용량 값도 크게 향상되었다. 최종적으로 투과율 측정 결과 액정디스플레이의 액정 배향막으로 적용하기에 적합한 것으로 나타났다.