• Applied Chemistry for Engineering
• /
• v.27 no.6
• /
• pp.555-564
• /
• 2016

In recent years, methanol has attracted much attention since it can be cleanly manufactured by the combined use of atmospheric $CO_2$ recycling and water splitting via renewable energy. For the concept of "methanol economy", an active methanol synthesis catalyst should be prepared in a sophisticated manner rather than by empirical optimization approach. Even though Cu/ZnO-based catalysts prepared by coprecipitation are well known and have been extensively investigated even for a century, fundamental understanding on the precipitation chemistry and catalyst nanostructure has recently been achieved due to complexity of the necessary preparation steps such as precipitation, ageing, filtering, washing, drying, calcination and reduction. Herein we review the recent reports regarding the effects of various synthesis variables in each step on the physicochemical properties of materials in precursor, calcined and reduced states. The relationship between these characteristics and the catalytic performance will also be discussed because many variables in each step strongly influence the final catalytic activity, called "chemical memory". All discussion focuses on how to prepare a highly active Cu/ZnO-based catalyst for methanol synthesis. Furthermore, the preparation strategy we deliver here would be utilized for designing other coprecipitation-derived supported metal or metal oxide catalysts.

• Economic and Environmental Geology
• /
• v.23 no.4
• /
• pp.393-409
• /
• 1990

Synthetic seismograms and deduced characteristic properties of the non-geometrical $S^*$ and $P^*$ waves are presented. These waves are excited on the free surface or an interface between two different media by an inhomogeneous P wave from a point source nearby, and propagate as homogeneous waves in the media. Synthetic seismograms are computed using an extended reflectivity method designed for buried source and receiver. An efficient computational procedure for propagator matrices of layers is devised to reduce the computational time and the RAM memory size in the implementation of the reflectivity method. Radiation patterns are obtained from the particle motions of the four types of the "*" waves, i.e., the $S^*$ wave generated near the free surface, and the reflected $S^*$, transmitted $S^*$ and transmitted $P^*$ waves generated near an interface. Some patterns show polarity changes of displacements and others reveal monotonic or non-monotonic variation of amplitude depending on the velocity structure. The decaying trend of amplitude with increasing epicentral distance are also shown for the head wave type of the "*" waves.

• Journal of Life Science
• /
• v.6 no.3
• /
• pp.178-184
• /
• 1996

Aloe(Aloe vera LINNE) has been used as a home medicine for the past several thousand in the world, and has been studied on various chronic degenerative diseases such as atherosclerosis, myocardiac infarction and hypertension. SMAP8, learning and memory impairment animal mode, were fed basic or experimental diets with 1.0% of freeze dried(FD)-Aloe powder for 8 months. This study was designed to investigate the effects of Aloe on body weight gain, grading score of senescence(GSS), triglyceride, total and LDL-cholesterol levels, and atherogenic index in serum of SAMP8, and also designed to investigate the effects of Aloe on cholesterol accumultions in mitochondria and microsome fractions of SAMP8 brain. Body weight gain was consistently lower in aloe group than in control group, but no significantly differences between them. Grading score of senescence resulted ina marked decreases pf 20% in 1.0% Aloe group compared with control group. Administrations of 1.0% aloe resulted ina marked decreases in 15% and 20% of triglyceride and cholesterol levels, respectively, and also significantly decreased in 15% of LDL-cholesterol levels and atherogenic index in serum of SAMP8 compared with control group. Cholesterol accumulations were significantly inhibited in 20% and 10% of mitochondria and microsome fractions of SAMP8 brain, respectively, by administration of 1.0% Aloe. These results suggest that administration of Aloe mau not only effectively inhibit chronic degenerative diseases in serum of SAMP8, but may also improve learning and memory impairments of SAMP8 brain.

• Journal of Life Science
• /
• v.6 no.2
• /
• pp.142-148
• /
• 1996

Aloe(Aloe arborescens M$_{ILL}$) has been used as a home medicine for the past several thousand in the world, and has been studied on anti-bacterial and anti-fungal activities, hypotension, atherosclerosis, myocardiac infartion, apoplexy, diabetes as a chronic digenerative disease, tumors, gastrointestinal tract, liver and pancreas' diseases, and genitourinary tract etc. SAMP8 as a learing and memory impairment animal model were fed basic and/or experimental diets with 1.0% freezing dried(FD)-aloe for 8 months. The passive avoidance tests such as acqusition trial and retention test were significantly higher in aloe group than in control group. Grading score of senescence resulted in a marked decreases in aloe group compared with control group. Acetylcholinesterase(AChE) activity was remarkably increased in aloe group compared with control group. Neurotransmitters such as dopamine(DA) and serotonin(5-HT) almost did not change by the feeding of aloe-added diet, but their metabolites such as homovanillic acid(HVA) and 5-hydroxy-indole acetic acid(5-HIAA) in aloe group were significantly increased compared with control group. Therefore, the ratios of HVA/DA and 5-HIAA/5-HT as a ratio of metabolite on neurotransmitter were significantly increased by the feeding of aloe-added diet. These results suggest that aloe vara may be activated acetylcholinesterase, the metabolite of neurotransmitter, and ratios of metabolite on neurotransmitter, resulting ina greater prevention of learning and memory impairments such as Alzheimertype dementia.

• Smart Media Journal
• /
• v.9 no.1
• /
• pp.30-37
• /
• 2020

Enforcing additional authentication to password-based authentication, in addition to attempting to increase the security of the password itself, helps to improve the security of the password authentication scheme. For a well-known problem of using strong passwords that differ from site to site, we propose a scheme for password generation and management with an inherent supplementary authentication. Like the so-called password manager, the scheme retrieves and presents a strong site-specific password whenever requested without requiring the user to remember multiple passwords. Unlike the existing methods, however, the scheme permits the password retrieval process to proceed only through the authenticated user's ownership verified smartphone. Hence, even for sites not enforcing or supporting two-factor authentication, the logon process can benefit from the scheme's assurance of enhanced security with its two-factor equivalent authentication. The scheme can also prevent an attacker from impersonating a user or stealing secrets even when the stored information of the server for password retrieval service or the user's smartphone is leaked.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2010.07a
• /
• pp.435-438
• /
• 2010

오늘날 많은 연구자들은 자율적 인간형 로봇 (Autonomous symbiotic human-robot)을 보조하기 위한 지식체계로 온톨로지의 개념을 사용한다. 이러한 연구는 룰 기반의 추론시스템을 지원하기 위해 온톨로지를 저장하는 데이터베이스 스키마를 설계하는데 초점을 맞추고 있다. 이러한 연구 뿐만 아니라 온톨로지 개념을 사용하는 가장 중요한 목적 중에 하나는 상황 추론이다. 이러한 관점에서 본 논문은 로봇이라는 환경에서 좀 더 지능적인 상황 추론 서비스를 제공하기 위해, 5W1H 기반의 로봇 지능 저장소라 불리는 로봇 메모리 저장소를 설계하는데 초점을 두고 있다. 기존 연구는 체계적이고 의미론적 5W1H를 고려하지 않거나 5W1H와 다른 개념 사이의 연광성의 결여에 많은 문제점을 가지고 있으며 이를 해결하기 위해 본 논문에서는 상황, 목적, 공간, 특징, 인간 그리고 5W1H의 온톨로지 지식을 저장할 수 있는 개념적인 모델인 로봇 메모리 모델을 설계한다. 또한 본 논문에서는 상황 추론을 지원하기 위해 로봇의 인스턴스 정보라고 불리는 자전적 기억 (Episodic Memory)를 효과적으로 저장하기 위한 5W1H 모델을 정의하며 이러한 모델을 물리적으로 저장하기 위한 관계형 데이터베이스 기반의 EventsEpisodicRBS를 설계한다. 결과적으로 이러한 연구를 통해서 자율적 인간형 로봇 환경에서 로봇이 지능적 서비스 제공의 핵심 모듈인 상황 추론을 지원하는데 큰 기여를 할 수 있는 하부 시스템으로서의 의미를 가질 수 있다.

• Korean Journal of Medicinal Crop Science
• /
• v.28 no.2
• /
• pp.85-94
• /
• 2020

Background: Alzheimer's disease (AD) is caused by various factors, such as cholinergic dysfunction, regulation of neurotrophic factor expression, and accumulation of amyloid-beta. We investigated whether or not a combination of Carthamus tinctorius L. seed and Taraxacum coreanum (CT) has a protective effect on scopolamine-induced memory impairment in a mouse model. Methods and Results: Mice were orally pretreated with CT (50, 100 and 200 mg/kg/day) for 14 days, and scopolamine (1 mg/kg/day) was injected intraperitoneally before subjecting them to behavior tests. CT-administered mice showed better novel object recognition and working memory ability than scopolamine-treated control mice. In T-maze and Morris water maze tests, CT (100 and 200 mg/kg/day) significantly increased space perceptive ability and occupancy to the target quadrant, respectively. In addition, 100 and 200 mg/kg/day of CT attenuated cholinergic dysfunction through inhibition of butyryl cholinesterase in brain tissue. Furthermore, CT-administered mice showed higher cyclic adenosine monophosphate-response element-binding protein (CREB) levels and lower amyloid precursor protein (APP) levels compared to scopolamine-treated control mice. Conclusions: CT improved scopolamine-induced memory impairment through inhibition of cholinergic dysfunction, up-regulation of CREB, and down-regulation of APP. Therefore, CT could be a useful therapeutic agent for AD with protective effects on cognitive impairment.

• The Journal of Korean Medicine
• /
• v.21 no.2
• /
• pp.25-36
• /
• 2000

Objectives : This study demonstrates the effects of Daejo-hwan on learning and memory impairment induced by L-NAME (75 mg/kg) treatment and on cerebral ischemic damage induced by middle cerebral artery (MCA) occlusion in rats. Methods : Daejo-hwan emulsion (73.3 mg/100 g/l ml) was administered to rats along a timed study schedule. The Moms water maze was used for learning and memory test of the rats. The MCA was occluded by using the intraluminal thread method. The brain slices were stained by 2 % triphenyl tetrazolium chloride (TTC) and 1 % cresyl violet solution. Infarct size, neuron cell number and size in penumbra was measured by using computer image analysis system. Results : 1. The escape latency of the Daejo-hwan treated group decreased significantly with respect to the control group. 2.The memory score of the Daejo-hwan treated group showed increase tendency, And the swimming distance was not different between the normal, the control, and the Daejo-hwan treated group. 3. The infarct size of the Daejo-hwan treated group decreased significantly with respect to the control group. 4. The total infarct volume of the Daejo-hwan treated group showed decrease tendency. And the brain edema index of the Daejo-hwan treated group decreased significantly with respect to the control group. 5. The neuron cell number and cell size in penumbra of the Daejo-hwan treated group increased significantly with respect to the control group. Conclusions : According to the above results, it is supposed that Daejo-hwan is clinically applicable to the vascular dementia.

• The Journal of the Korea Contents Association
• /
• v.10 no.12
• /
• pp.223-235
• /
• 2010

As the funeral service is on ritual of addressing death that is the final phase of life, it can be said to be the final stage of welfare service. It is developing into the stage of make-up, which reproduces the image of reality or expresses with the better appearance from the level of recovery technique, which restores the final form of the dead. This is caused by a request of the bereaved family with the aim of remembering the dead's final image with good looks. Methods, which are being changed by period, can be found in a record. As this funeral make-up is one field of special make-up, it is systematically made into proper application method along with the development in special materials. Thus, it will become one of the most important courses henceforth in our funeral culture available for beautifully decorating the dead's final image. In order to satisfy the request of the bereaved family, it is necessary to made floral decoration, casket cloth, and acoustic effect including the casket stage of worshipping the dead inside the funeral hall.

• Journal of Korea Game Society
• /
• v.11 no.6
• /
• pp.103-113
• /
• 2011

In this paper, we propose gesture recognition based 3D Serious Games to prevent dementia. These games are designed to enhance the effect of preventing dementia by helping increase brain usage and physical activities of users by the entire body gesture recognition. The existing cameras used for gesture recognition technology are limited in terms of recognition ratio and operation range. For more stable recognition of the body gestures, we recognized users with a 3D depth camera, obtained joint data of users, and analyzed joint motions to recognize gestures of the body. Game contents were designed to practice memory, reasoning, calculation, and spatial recognition focusing on the atrophy of brain cells as a major cause of dementia. Game results of each user were saved and analyzed to measure how their recognition skills improved.