• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.298.1-298.1
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• 2016

Two-dimensional materials have been received significant interest after the discovery of graphene due to their fascinating electronic and optical properties for the application of novel devices. However, graphene lack of certain bandgap which is essential requirement to achieve high performance field-effect transistors. Analogous to graphene materials, molybdenum disulfide ($MoS_2$) as one of transition-metal dichalcogenides family presents considerable bandgap and exhibits promising physical, chemical, optical and mechanical properties. Here we studied nonvolatile memory based on $MoS_2$ which is grown by chemical vapor deposition (CVD) method. $MoS_2$ growth was taken on $1.5{\times}1.5cm^2$ $SiO_2$/Si-substrate. The samples were analyzed by Raman spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy. Current-voltage (I-V) characteristic was carried out HP4156A. The CVD-$MoS_2$ was analyzed as few layers and 2H-$MoS_2$ structure. From I-V measurement for two metal contacts on CVD-$MoS_2$ sample, we found typical resistive switching memory effect. The device structures and the origin of nonvolatile memory effect will be discussed.

• Journal of Korean Neurosurgical Society
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• v.52 no.1
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• pp.21-26
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• 2012

Objective : To evaluate a new posterior atlantoaxial fixation technique using a nitinol shape memory loop as a simple method that avoids the risk of vertebral artery or nerve injury. Methods : We retrospectively evaluated 14 patients with atlantoaxial instability who had undergone posterior C1-2 fusion using a nitinol shape memory loop. The success of fusion was determined clinically and radiologically. We reviewed patients' neurologic outcomes, neck disability index (NDI), solid bone fusion on cervical spine films, changes in posterior atlantodental interval (PADI), and surgical complications. Results : Solid bone fusion was documented radiologically in all cases, and PADI increased after surgery (p<0.05). All patients remained neurologically intact and showed improvement in NDI score (p<0.05). There were no surgical complications such as neural tissue or vertebral artery injury or instrument failure in the follow-up period. Conclusion : Posterior C1-2 fixation with a nitinol shape memory loop is a simple, less technically demanding method compared to the conventional technique and may avoid the instrument-related complications of posterior C1-2 screw and rod fixation. We introduce this technique as one of the treatment options for atlantoaxial instability.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.1
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• pp.55-59
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• 2014

Dehydroevodiamine HCl (DHED) has been reported to prevent memory impairment and neuronal cell loss in a rat model with cognitive disturbance. We investigated the effect of DHED on memory impairment and behavioral abnormality caused by stress. We demonstrated that DHED can improve stress-induced memory impairments and depression-like behaviors by using open-field test, Y-maze test and forced swimming test. DHED treatment significantly recovered the decreases in the levels of neural cell adhesion molecule (NCAM) proteins caused by stress and the decreases in cell viability. Our results suggested that DHED is a potential drug candidate for neuronal death, memory impairment and depression induced by stress.

• Korean Journal of Materials Research
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• v.28 no.7
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• pp.381-390
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• 2018

Shape memory alloys(SMAs) have revolutionized the material engineering sciences as they exhibit exclusive features i.e. shape memory effect(SME) and super-elasticity. SMAs are those alloys that when deform return to their predeformed shape upon heating, they also restore their original shape by removing the load. Research on properties of newly advent of several types of ferrous based shape memory alloys(Fe-SMAs), shows that they have immense potential to be the counterpart of Nitinol(NiTi-SMA). These Fe-SMAs have been used and found to be effective because of their low cost, high cold workability, good weldability & excellent characteristics comparing with Nitinol(high processing cost and low cold workability) SMAs. Some of the Fe-SMAs show super-elasticity. Fe-SMAs, especially Fe-Mn-Si alloys have an immense potential for civil engineering structures because of its unique properties e.g. two-way shape memory effect, super elasticity and shape memory effect as well as due to its low cost, high elastic stiffness and wide transformation hysteresis comparative to Nitinol. Further research is being conducted on SMAs to improve and impinge better attributes by improving the material compositions, quantifying the SMA phase transition temperature etc. In this research pre-existing Fe-SMAs are categorised and collected in a tabulated form. An analysis is performed that which category is mostly available. Last 50 years data of Fe-SMA publications and US Patents is collected to show its importance in terms of increasing research on such type of alloys to invent different compositions and applications. This data is analysed as per different year groups during last 50 years and it was analysed as per whether the keywords exist in title of an article or anywhere in the article. It was found that different keywords related to Fe-SMAs/categories of Fe-SMAs, almost don't exist in the title of articles. However, these keywords related to Fe-SMAs/categories of Fe-SMAs, exist inside the article but still there are not too many publications related to Fe-SMAs/categories of Fe-SMAs.

• Journal of Ginseng Research
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• v.20 no.3
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• pp.226-232
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• 1996

This study was performed to investigate the effect of red ginseng extract including some vitamin B groups as test drug on learning and memory in mice. Single and repeated administrations of the test drug improved the acquisition and the process of consolidation in the tests using step-through and step-down apparatus, indicating this test drug improved learning and memory. However, the test drug did not improve scopolamine-induced amnesia. These results suggest that test drug may be useful as a nootropic agent.

• Korean Journal of Child Studies
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• v.12 no.1
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• pp.21-37
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• 1991

The present research studied the effectiveness of specific strategy training in memory awareness on children's memory performance. The subjects were 60 children, 30 six-year-olds and 30 eight-year-olds. Free recall scores and use of a rehearsal strategy (exposure durations) based on Belmont & Butterfield (1971) were used to measure children's performance in three memory tasks. All subjects were randomly assigned to one of three experimental groups: the control group with no training, the chunking and rehearsal strategy training group, and the chunking and rehearsal strategy training combined with memory awareness strategy. The data were analyzed with two-way ANOVA, three-way ANOVA with repeated measures, and Student-Newman-Keuls post hoc test. There were significant differences among the three groups both in the free recall score and in the use of the rehearsal strategy. The mnemonic strategic training with memory awareness strategy was the most effective on both free recall and use of rehearsal strategy. The effects of the mnemonic strategy training with memory awareness strategy were more effective for the 8-year-olds than the 6-year-olds.

• Journal of Ginseng Research
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• v.20 no.1
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• pp.7-14
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• 1996

This study was performed to examine the effect of red ginseng total saponin and extract on memory in mice using one trial step-down type passive avoidance method. Red ginseng total saponins (No. 1: PD/PT ratio=1.24, No. 2: PD/PT ratio=1.47) were prepared with the different mixing ratio by using the parts of red ginseng. In single administration of total saponin No. 1 (100 mg/ kg, bw) or No. 2 (50 mg/kg, bw) increased the latency time as compared with control group but was not statistically significant. Treatment of total saponin No. 1 (50 mg/kg, bw) for 10 days produced an increase of latency time but was not statistically significant. In scopolamine-induced memory deficient mice total saponin No. 1 (50 mg/kg, bw) and No. 2 (100 mg/kg, bw) significantly improved the latency time. These results show that red ginseng total saponin may improve the memory of sco-polamine-induced memory deficient mice and have nootropic activity.

• Korean Management Science Review
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• v.26 no.1
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• pp.171-182
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• 2009

We consider the inventory replenishment problem and the vehicle routing problem simultaneously in the vending machine operation. This problem is known as the inventory routing problem. We design a memory cell in the clonal selection algorithm. The memory cell store the best solution of previous solved problem and use an initial solution for next problem. In general, the other clonal selection algorithm used memory cell for reserving the best solution in current problem. Experiments are performed for testing efficiency of the memory cell in demand uncertainty. Experiment result shows that the solution quality of our algorithm is similar to general clonal selection algorithm and the calculations time is reduced by 20% when the demand uncertainty is less than 30%.

• Proceedings of the Korean Society of Life Science Conference
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• 2006.09a
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• pp.73.1-73.1
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• 2006

• Journal of Physiology & Pathology in Korean Medicine
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• v.34 no.2
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• pp.81-87
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• 2020

Cognitive impairment is symptoms of dementia, a degenerative brain disease that is drawing attention in a rapidly aging society. This study was conducted to investigate the improvement of cognitive function of Leonurus japonicus on scopolamine-induced memory impairment in mice and the effect and mechanism of memory recovery. In vivo studies were conducted on mice orally pretreated with L. japonicus in doses of 50, 100 and 200 mg/kg (p.o.) and scopolamine (1 mg/kg, i.p.) were injected 30 min before the behavioral task. 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 (AChE) inhibition activity evaluated by Ellman's method. In behavior studies showed that L. japonicus has an improved the memory of scopolamine-treated mice in Y-maze, passive avoidance and Morris water maze test. In addition, L. japonicus was also exerted free radical scavenging activity and inhibited acetyl cholinesterase activity. These results suggest that L. japonicus improves short-term and long-term memory in scopolamine-induced memory decline model and prevents scopolamine-induced memory impairments through in reduced oxidative stress and acetyl cholinesterase inhibition effect. Thus, L. japonicus is related to functional medicinal materials for prevention and treatment of human dementia patients.