• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.440-440
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• 2011

We report on the non-volatile memory characteristics of a bistable organic memory (BOM) device with Au nanoparticles (NPs) embedded in a conducting poly N-vinylcarbazole (PVK) colloids hybrid layer deposited on flexible polyethylene terephthalate (PET) substrates. Transmission electron microscopy (TEM) images show the Au nanoparticles distributed isotropically around the surface of a PVK colloid. The average induced charge on Au nanoparticles, estimated using the C-V hysteresis curve, was large, as much as 5 holes/NP at a sweeping voltage of ${\pm}3$ V. The maximum ON/OFF ratio of the current bistability in the BOM devices was as large as $1{\times}105$. The cycling endurance tests of the ON/OFF switching exhibited a high endurance of above $1.5{\times}105$ cycles and a high ON/OFF ratio of ~105 could be achieved consistently even after quite a long retention time of more than $1{\times}106$ s.

• 대한전자공학회논문지SD
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• 제47권2호
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• pp.1-6
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• 2010

수직형 채널을 가지는 4-비트 SONOS 플래시 메모리를 이용하여, 고집적화된 3차원 형태의 NOR 플래시 메모리 어레이를 제안하였다. 수직형 채널을 가지기 때문에, 집적도의 제한 없이 충분히 긴 채널을 가질 수 있다. 이로 인하여, 짧은 채널의 멀티 비트 메모리에서 발생할 수 있는 비트 간의 간섭효과, 짧은 채널 효과, 및 전하 재분포 현상을 해결 할 수 있다. 또한, 제시된 어레이는 3차원 형태를 기반으로 고집적화되어, 발표된 NOR 중에서 최소의 셀 크기 값인 $1.5F^2$/bit을 가진다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1562-1564
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• 2003

In this study, PZT thin films were fabricated using sol-gel processing onto Si/$SiO_2$/Ti/Pt substrates. PZT sol with different Zr/Ti ratio(20/80, 30/70, 40/60, 52/48) were prepared, respectively. The films were fabricated by using the spin-coating method on substrates. The films were heat treated at $450^{\circ}C,\;650^{\circ}C$ by rapid thermal annealing(RTA). The preferred orientation of the PZT thin films were observed by X-ray diffraction(XRD), and Scanning electron microscopy(SEM). All of the resulting PZT thin films were crystallized with perovskite phase. The fine crystallinity of the films were fabricated. Also, we found that the ferroelectric properties from the dielectric constant of the PZT thin films were over 600 degrees, P-E hysteresis constant. And the leakage current densities of films were lower than $10^{-8}A/cm^2$. It is concluded that the PZT thin films by sol-gel process to be convinced of application for ferroelectric memory device.

• 동의생리병리학회지
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• 제16권5호
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• pp.976-988
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• 2002

The aim of this study was to examine the memory and attention enhancement effect of YMG-1 and YMG-2, which are modified herbal extracts from Yukmijihwang-tang (YMJ). YMJ, composing six herbal medicine, has been used for restoring the normal functions of the body to consolidate the constitution, nourishing and invigorating the kidney functions for hundreds years in Asian countries. A series of studies reported that YMJ and its components enhance memory retention, protects neuronal cell from reactive oxygen attack and boost immune activities. Recently the microarray analysis suggested that YMG-1 protects neurodegeneration through modulating various neuron specific genes. A total of 55 subjects were divided into three groups according to the treatment of YMG-1 (n=20), YMG-2 (n=20) and control (C; n=15) groups. Before treatments, all of subjects were subjected to the assessments on neuropsychological tests of K-WAIS test, Rey-Kim memory test, and psychophysiological test of Event-Related Potential (ERP) during auditory oddball task and repeated word recognition task. They were repeatedly assessed with the same methods after drug treatment for 6 weeks. Although no significant effect of drug was found in Rey-Kim memory test, a significant interaction (P = .010, P < 0.05) between YMG-2 and C groups was identified in the scores digit span and block design, which are the subscales of K-WAIS. The very similar but marginal interaction (P = .064) between YMG-1 and C groups was found too. In ERP analysis, only YMG-1 group showed decreasing tendency of P300 latency during oddball task while the others tended to increase, and it caused significant interaction between session and group (p= .004). This result implies the enhancement of cognitive function in due to consideration of relationship between P300 latency and the speed of information processing. However, no evidence which could demonstrate the significant drug effect was found in neither amplitude or latency. These results come together suggest that YMG-1, 2 may enhance the attention, resulting in enhancement of memory processing. For elucidating detailed mechanism of YMG on learning and memory, the further studies are necessary.

• 한국항공우주학회지
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• 제36권2호
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• pp.195-201
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• 2008

본 논문에서는 소형화, 경량화 및 저전력화를 목표로 개발된 과학기술위성 2호 대용량 메모리 유닛(Mass Memory Unit, MMU)의 준비행모델(Proto Flight Model, PFM)을 통해서 과학기술위성 1호 대용량 메모리 유닛과의 성능을 비교 하였다. 탑재체로부터의 수신 속도와 XTX로의 전송 속도는 각각 200Kbps와 10Mbps이다. 실험실에서의 성능시험과 위성에 조립된 상태에서의 성능 및 환경 시험을 통해서 그 성능을 확인 하였다.

• 한국음향학회지
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• 제15권6호
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• pp.16-25
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• 1996

본 논문에서는 한글의 유형 분류를 CAM(Content Addressable Memory)을 이용하여 칩으로 설계하였다. 문자 인식의 전 과정을 종전의 소프트웨어에 의해서 손차적으로 처리할 경우, 실시간 처리가 가능한 고속 문자 인식기의 구현에는 어려움이 있다. 따라서, 이들 실시간으로 처리하기 위해서는 파이프라인식 하드웨어로 구현하여 시간적인 병렬성을 갖도록 하는 것이 필요하다. 하드웨어로 용이하게 구현하기 위해서 고속 병렬 매치 기능을 가진 CAM을 이용하였으며, 20개의 참조패턴만으로 유형을 분류하였다. 설계한 회로는 DAZIX의 DLAB을 사용하여 결과를 평가하였으며, 그 결과 자당 $1.6{\mu}S$의 처리속도를 보였다. 또한, C-언어로 구현하여 그 결과를 비교하였다.

• Biomolecules & Therapeutics
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• 제21권5호
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• pp.381-390
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• 2013

The purpose of this study was to examine whether ginsenoside Rg3 (GRg3) could improve learning and memory impairments and inflammatory reactions induced by injecting lipopolysaccharide (LPS) into the brains of rats. The effects of GRg3 on proinflammatory mediators in the hippocampus and the underlying mechanisms of these effects were also investigated. Injection of LPS into the lateral ventricle caused chronic inflammation and produced deficits in learning in a memory-impairment animal model. Daily administration of GRg3 (10, 20, and 50 mg/kg, i.p.) for 21 consecutive days markedly improved the LPS-induced learning and memory disabilities demonstrated on the step-through passive avoidance test and Morris water maze test. GRg3 administration significantly decreased expression of pro-inflammatory mediators such as tumor necrosis factor-${\alpha}$, interleukin-1${\beta}$, and cyclooxygenase-2 in the hippocampus, as assessed by reverse transcription-polymerase chain reaction analysis and immunohistochemistry. Together, these findings suggest that GRg3 significantly attenuated LPS-induced cognitive impairment by inhibiting the expression of pro-inflammatory mediators in the rat brain. These results suggest that GRg3 may be effective for preventing or slowing the development of neurological disorders, including Alzheimer's disease, by improving cognitive and memory functions due to its anti-inflammatory activity in the brain.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권2호
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• pp.68-73
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• 2006

We propose a damascene gate FinFET with Si nanocrystals implemented on bulk silicon wafer for low voltage flash memory device. The use of optimized SRON (Silicon-Rich Oxynitride) process allows a high degree of control of the Si excess in the oxide. The FinFET with Si nanocrystals shows high program/erase (P/E) speed, large $V_{TH}$ shifts over 2.5V at 12V/$10{\mu}s$ for program and -12V/1ms for erase, good retention time, and acceptable endurance characteristics. Si nanocrystal memory with damascene gate FinFET is a solution of gate stack and voltage scaling for future generations of flash memory device. Index Terms-FinFET, Si-nanocrystal, SRON(Si-Rich Oxynitride), flash memory device.

• 대한본초학회지
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• 제35권5호
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• pp.33-39
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• 2020

Objectives : Increasing evidence supports the biological and pharmacological activities of essential oils on the central nervous system such as pain, anxiety, attention, arousal, relaxation, sedation and learning and memory. The purpose of present work is to investigate the protective effect and molecular mechanism of cypress essential oil (CEO) against scopolamine (SCO)-induced cognitive impairments in C57BL/6 mice. Methods : A series of behavior tests such as Morris water maze, passive avoidance, and fear conditioning tests were conducted to monitor learning and memory functions. Immunoblotting and RT-PCR were also performed in the hippocampal tissue to determine the underlying mechanism of CEO. Results : SCO induced cognitive impairments as assessed by decreased step-through latency in passive avoidance test, relatively low freezing time in fear conditioning test, and increased time spent to find the hidden platform in Morris water maze test. Conversely, CEO inhalation significantly reversed the SCO-induced cognitive impairments in C57BL/6 mice comparable to control levels. To elucidate the molecular mechanisms of memory enhancing effect of CEO we have examined the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus. CEO effectively elevated the protein as well as mRNA expression of BDNF via activation of cAMP response element binding protein (CREB). Conclusions : Our findings suggest that CEO inhalation effectively restored the SCO-impaired cognitive functions in C56BL/6 mice. This learning and memory enhancing effect of CEO was partly mediated by up-regulation of BDNF via activation of CREB.

• 동의생리병리학회지
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• 제32권6호
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• pp.375-383
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• 2018

This study was conducted to investigate the cognitive improvement and memory recovery effects of Korean and Chinese Crataegus pinnatifida ethanolic extracts on scopolamine-induced memory impairment in mice. In vivo studies were carried out with mice treated with Korean Crataegus pinnatifida extracts (KCF) and Chinese Crataegus pinnatifida extracts (CCF) in doses of 5 and 50 mg/kg (p.o.) and scopolamine was injected 30 min before the behavioral testing. Antioxidant activity was assessed by 2,2-diphenyl-1-picryl hydrazyl (DPPH) assay and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, and acetylcholinesterase inhibition by Ellman's modified method. The chlorogenic acid and hyperoside as marker compounds of KCF and CCF was quantified by ultra-performance liquid chromatography analysis (UPLC). Results showed that KCF was more contained high content of chlorogenic acid and hyperoside than CCF. In addition, KCF was more exerted free radical (DPPH and ABTS) scavenging activity and blocked AChE activity than CCF. In vivo studies also showed that KCF administration has a further improved the memory of scopolamine-treated mice than CCF in Y-maze test, passive avoidance test and Morris water maze test. These results revealed that KCF more prevents scopolamine-induced memory impairments through antioxidant and acethylcholinesterase inhibition effect compared CCF.