• E2M - 전기 전자와 첨단 소재
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• 제8권5호
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• pp.626-632
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• 1995

In this paper, The effect of the impedances in SNOSFET's memory devices has been developed. The effect of source and drain impedances measured by means of two bias resistances - field effect bias resistance by inner region, external bias resistance. The effect of the impedances by source and drain resistance shows the dependence of the function of voltages applied to the gate. It shows the differences of change in source drain voltage by means of low conductance state and high conductance state. It shows the delay of threshold voltages. The delay time of low conductance state and high conductance state by the impedances effect shows 3[.mu.sec] and 1[.mu.sec] respectively.

• 한국정밀공학회지
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• 제24권10호
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• pp.131-136
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• 2007

In this paper, we estimated the effects of different color stimulation on the cognitive function of human quantitatively. For the stimulations we used color lights with 6 color filters such as red, yellow, green, blue, violet and white. The experiment was performed in a soundproof chamber. 50 young male and female subjects were participated in the experiment. To find the appropriate color cognitive function, the endogenous visuospatial attention task(EVAT) and one back working memory task(OWMT) were performed. The reaction time and accuracy degree were measured. The results showed that the reaction time of EVAT was the fastest and the accuracy degree of attention task was the highest in green environment. The reaction time of OWMT was the fastest in yellow and the accuracy degree of memory task was the highest in blue. For physiological parameters, we measured electrocardiogram(ECG) and HRV spectrum analysis, HF/LF color environment. These results can be used as an indicator in the design of color environment and clinical applications.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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• pp.261-262
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• 2003

Shape memory polyurethane (PU) with soft and hard segments has been extensively researched since its discovery by Mitsubishi in 1988 [1]. Hard segments can be formed via hydrogen bonding and crystallization, function as physical crosslinks below melting point (Tm). The reversible phase transformation of the soft segment is responsible for the shape memory effect. (omitted)

• 생약학회지
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• 제52권1호
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• pp.55-60
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• 2021

Belamcandae Rhizoma (BR), the rhizome of Belamcanda chinensis (L.) DC., possesses various biological properties such as anti-inflammatory activity, antioxidant activity and antimutagenic activity. However, there have been no studies on the anti-amnesic effect of BR. In this study, we assessed the improvement effect of BR extract on scopolamine-induced amnesia in mice. ICR mice were administrated with BR (50, 100 or 200 mg/kg, p.o.) and were subsequently injected of scopolamine (1 mg/kg, i.p.) 30 min before behavioral tasks (Y-maze, passive avoidance and Morris water maze tasks). To further assess the possible mechanisms of BR, the ex vivo acetylcholinesterase (AChE) activity was also evaluated. BR could ameliorate scopolamine-induced memory impairment and could regulate the cholinergic function by inhibiting the AChE activity. These data demonstrated that BR exert candidate extract against amnesia by restoring the cholinergic activity.

• 동의생리병리학회지
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• 제16권6호
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• pp.1236-1242
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• 2002

In order to make an efficient prescription and cope with dementia, learning and memory functions of Sprague-Dawley model rats were tested with Morris water maze. And to evaluate the effect of the sample drug(CHM) on choline acetyltranferase and acetylcholine esterase, immunoreactive measurement and enzymatic activity measuring were carried out. Rats were injected with ibotenic acid through hippocampus CA1 and CA3 area. The results are as following. CHM improves the learning ability in the acquisition test and memory function in the retention test significantly. And CHM increases the level of AChE which is resolving acetylcholine. Though it doesn't increase the level of ChAT significantly which is synthesizing acetylcholine, but it shows the tendency of increase. So these results show that CHM improve the cholinergic catabolism and anabolism, and the increment of metabolic activity of cholinergic system. Thus it can be concluded that CHM will be helpful to cholinergic brain disease induced by primary or senile reduction of acetylcholine secretive activity.

• 대한물리의학회지
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• 제18권1호
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• pp.87-97
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• 2023

PURPOSE: The purpose of this study was to investigate the effect of multimodal intervention through VR (virtual reality)-based immersion program on the cognitive function and brain activity of patients with mild cognitive impairment. METHODS: The subjects of the study were 10 people in the experimental group who applied a complex intervention that performed cognitive tasks using the movement of the upper extremities through the VR program, and 10 people in the control group who received traditional occupational therapy. After the study intervention was applied 5 times a week, 30 minutes a day for a total of 8 weeks, LOTCA-G(Lowenstein Occupational Therapy Cognitive Assessment for Geriatric Population) and NIRSIT LITE were used to compare. RESULTS: Significant differences in cognitive function and brain activity were noted between the pre- test and post-test in the experimental group. Brain activity showed statistically significant differences in four channels of the working memory domain and one channel of the metacognitive domain (p < . 05). Comparative analysis of the difference between the two groups revealed statistically significant differences in cognitive function and brain activity. The brain activity showed statistically significant differences in three channels of the working memory domain and one channel of the metacognitive domain (p < .05). CONCLUSION: Through the results of this study, it was found that the complex intervention of performing cognitive tasks using upper extremity movements through the VR program had a positive effect on the cognitive function of patients with mild cognitive.

• Journal of Ginseng Research
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• 제37권1호
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• pp.100-107
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• 2013

This study examined the effect of fermented ginseng (FG) on memory impairment and ${\beta}$-amyloid ($A{\beta}$) reduction in models of Alzheimer's disease (AD) in vitro and in vivo. FG extract was prepared by steaming and fermenting ginseng. In vitro assessment measured soluble $A{\beta}42$ levels in HeLa cells, which stably express the Swedish mutant form of amyloid precursor protein. After 8 h incubation with the FG extract, the level of soluble $A{\beta}42$ was reduced. For behavioral assessments, the passive avoidance test was used for the scopolamine-injected ICR mouse model, and the Morris water maze was used for a transgenic (TG) mouse model, which exhibits impaired memory function and increased $A{\beta}42$ level in the brain. FG extract was treated for 2 wk or 4 mo on ICR and TG mice, respectively. FG extract treatment resulted in a significant recovery of memory function in both animal models. Brain soluble $A{\beta}42$ levels measured from the cerebral cortex of TG mice were significantly reduced by the FG extract treatment. These findings suggest that FG extract can protect the brain from increased levels of $A{\beta}42$ protein, which results in enhanced behavioral memory function, thus, suggesting that FG extract may be an effective preventive or treatment for AD.

• 한국융합학회논문지
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• 제10권5호
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• pp.95-102
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• 2019

본 연구는 정상 성인을 무작위로 급속안구움직임(saccadic eye movement, SEM)군과 의식적손가락움직임(intentional finger movement, IFM) 군으로 구분하여 2주 동안 중재를 실시한 후 숫자외우기 검사와 n-back 검사를 사용하여 인지기능의 변화를 알아보았다. 그 결과 IFM군의 단기기억은 시간이 지날수록 유의하게 상승하였으며, 추적 검사에서는 군간 차이를 나타내었다. IFM군의 n-back은 수행시간, 오류횟수, 정확률에서 시간이 지날수록 유의한 효과를 나타내었다. SEM군의 n-back은 수행시간과 정확률에서 시간이 지날수록 유의한 효과를 나타내었다. 결론적으로 인지기능 향상에는 단일 자극인 SEM보다 대뇌겉질을 광범위하게 활성화 시킬 수 있는 다중 자극인 IFM 방법이 인지기능 향상의 중재 방법으로 더 유용할 것으로 생각된다.

• 대한전자공학회논문지TC
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• 제49권1호
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• pp.47-52
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• 2012

전력증폭기는 기지국의 효율을 결정하는 중요한 요소이며, 효율성 제고를 위하여 GaN증폭소자를 사용한 Doherty 전력증폭기 구조에 대한 연구가 지속되고 있다. Doherty 전력증폭기의 메모리 효과는 선형성과 효율특성과 연관된 동작특성에 큰 영향을 미친다. 본 논문에서는 GaN Doherty 전력증폭기의 전열적인 비선형성 모델링과 전열적 메모리 효과가 GaN Doherty 증폭기의 왜곡형성과 보상에 대하여 연구하였다. GaN Doherty 증폭기의 전열적 메모리 특성을 모델링하기 위하여 순시적으로 소모되는 전력과 순시 접합온도의 정확한 관계식을 정립하였다. 제안된 모델의 파라미터로부터 GaN Doherty 전력증폭기의 비선형왜곡과 전열적 메모리 효과를 보상할 수 있는 전치왜곡선형화기 모델을 설계하였다. 제안된 모델의 성능평가는 37dBm GaN Doherty 전력증폭기와 ADS Tool을 사용하여 왜곡특성 성능개선정도를 검증하였다. 선형화된 GaN 전력증폭기의 2-tone 출력스펙트럼에서 약 16 dB의 왜곡개선효과를 보였다.

• 한국식품과학회지
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• 제54권1호
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• pp.52-58
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• 2022

Phosphatidylserine (PS) is an essential component of the cerebral cortex and is associated with cognitive function. In this systematic review, the effects of PS on cognitive function in the elderly population are examined. The literature search included PubMed, EMBASE, Cochrane, and Web of Science databases. Subsequently, nine studies, including five randomized controlled trials and four pre-post studies, were selected. There were 961 participants in the selected studies; PS dosage varied from 100 to 300 mg/d, and the experimental period ranged from 6 weeks to 6 months. Five out of the nine selected studies were assessed to have a 'low' risk of bias, whereas the other four studies were assessed to have 'some concerns' regarding the risk of bias. The results of the meta-analysis concluded that PS had a positive effect on the memory of older adults with cognitive decline. Thus, PS appears to improve age-associated cognitive decline, especially memory, with no adverse effects.