• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.387-387
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• 2013

Currently, the flash memory and the dynamic random access memory (DRAM) have been used in a variety of applications. However, the downsizing of devices and the increasing density of recording medias are now in progress. So there are many demands for development of new semiconductor memory for next generation. Magnetic random access memory (MRAM) is one of the prospective semiconductor memories with excellent features including non-volatility, fast access time, unlimited read/write endurance, low operating voltage, and high storage density. MRAM is composed of magnetic tunnel junction (MTJ) stack and complementary metal-oxide semiconductor (CMOS). The MTJ stack consists of various magnetic materials, metals, and a tunneling barrier layer. Recently, MgO thin films have attracted a great attention as the prominent candidates for a tunneling barrier layer in the MTJ stack instead of the conventional Al2O3 films, because it has low Gibbs energy, low dielectric constant and high tunneling magnetoresistance value. For the successful etching of high density MRAM, the etching characteristics of MgO thin films as a tunneling barrier layer should be developed. In this study, the etch characteristics of MgO thin films have been investigated in various gas mixes using an inductively coupled plasma reactive ion etching (ICPRIE). The Cl2/Ar, CH3OH/Ar, and CH4/Ar gas mix were employed to find an optimized etching gas for MgO thin film etching. TiN thin films were employed as a hard mask to increase the etch selectivity. The etch rates were obtained using surface profilometer and etch profiles were observed by using the field emission scanning electron microscopy (FESEM).

• 대한환경공학회지
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• 제32권9호
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• pp.857-861
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• 2010

매년 대도시 지역과 그 주변에 오존농도가 환경기준을 초과하는 빈도가 증가하여 오존주의보 발령횟수가 증가하는 추세이다. 따라서 오존의 전구물질인 VOCs에 대한 제어과정이 시급한 실정이다. 국내에서 발생되는 폐기물 중 소각재와 하수슬러지는 발생량이 증가됨에 따라 그 처리 방안이 요구되고 있다. 소각재와 다른 폐기물을 이용하여 건축외장재를 제조하여 소각재 중의 유해중금속을 안정화시키고 제조한 외장재로 대기 중의 VOCs를 흡착, 제거할 수 있다면 환경 부하 저하, 자원 재활용 및 VOCs control이라는 면에서 매우 유용할 것으로 판단된다. 제조한 외장재의 VOC 흡착특성을 알아보기 위해 벤젠 흡착실험과 SEM분석, BET분석을 수행하였고 외장재의 흡착특성을 유지하기 위해 광촉매 코팅을 하여 그 효과를 알아보았다. 실험결과 벤젠 제거 능력은 74~96%로 높게 나타났고 제조한 외장재의 표면에는 다양한 공극이 발달되어 있음을 알 수 있었다. 또한, 외장재의 환경안정성을 알아보기 위해 중금속 용출실험을 수행한 결과 중금속이 안정화 되어 용출양이 현저히 감소한 것을 알 수 있었다.

• Restorative Dentistry and Endodontics
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• 제41권4호
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• pp.246-254
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• 2016

Objectives: The aim of this investigation was to give insights into the impact of carbohydrate-electrolyte drinks on the likely capacity of enamel surface dissolution and the influence of human saliva exposure as a biological protective factor. Materials and Methods: The pH, titratable acidity (TA) to pH 7.0, and buffer capacity (${\beta}$) of common beverages ingested by patients under physical activity were analyzed. Then, we randomly distributed 50 specimens of human enamel into 5 groups. Processed and natural coconut water served as controls for testing three carbohydrate-electrolyte drinks. In all specimens, we measured surface microhardness (Knoop hardness numbers) and enamel loss (profilometry, ${\mu}m$) for baseline and after simulated intake cycling exposure model. We also prepared areas of specimens to be exposed to human saliva overnight prior to the simulated intake cycling exposure. The cycles were performed by alternated immersions in beverages and artificial saliva. ANOVA two-way and Tukey HDS tests were used. Results: The range of pH, TA, and ${\beta}$ were 2.85 - 4.81, 8.33 - 46.66 mM/L and 3.48 - $10.25mM/L{\times}pH$, respectively. The highest capacity of enamel surface dissolution was found for commercially available sports drinks for all variables. Single time human saliva exposure failed to significantly promote protective effect for the acidic attack of beverages. Conclusions: In this study, carbohydrate-electrolyte drinks usually consumed during endurance training may have a greater capacity of dissolution of enamel surface depending on their physicochemical proprieties associated with pH and titratable acidity.

• Advances in Traditional Medicine
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• 제10권3호
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• pp.191-199
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• 2010

Acanthopanax Koreanum stem (AK) has been used in Korea as a tonic and sedative as well as a drug with ginseng like activities. The purpose of our present study was to investigate the effects of AK extract (AKE) and Eleutheroside E, major component of AKE on an exacerbated immune function through utilization of protein-energy malnutrition (PEM) diet by using forced swimming test (FST). The immobility time were significantly decreased in the AKE or Eleutheroside E-administrated group compared with the control group on the FST (P < 0.05). The level of blood parameters were not changed significantly. PEM-induced weight loss of mice was reduced by oral administration of 500 mg/kg AKE. AKE oral administration improved the nutritional status such as the food efficiency ratio and the adrenal gland weight. AKE treatment significantly increased the production of interferon (IFN)-$\gamma$ compared with unstimulated splenocytes but not interleukin (IL)-4. Eleutheroside E also significantly increased the IFN-$\gamma$ production but not IL-2 and IL-4 in T cell line, MOLT-4 cells. These results suggest that AKE and Eleutheroside E may influence to immune-enhancing through increasing the physical endurance capacity and immune cell activation.

• 한방재활의학과학회지
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• 제30권2호
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• pp.37-46
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• 2020

Objectives In this study, we analyzed the effect of Dioscoreae Rhizoma on exercise practice ability and blood fatigue variable factor in the forced swimming test. Methods Male mice were divided into four group. Mice were administrated with saline, Discorae Rhizoma extracted by water (DRW), Discorae Rhizoma extracted by 30% ethanol (DRE), red ginseng (RG), orally once per day, for 1 week. Exercise performance was evaluated by exhaustive swimming time and weights. Glycogen contents of liver and soleus muscle were measured at the end of the experiment. In addition, the biochemical parameters such as asparate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen, creatine, lactate dehydrogenase (LDH), ammonia, triglycerides (TG), total cholesterol (TC) and free fatty acid (FFA) were analyzed. Results Both DRW and DRE showed an improvement of swimming endurance compared with control group. Levels of ALT, ammonia, TG, TC and FFA were significantly decreased in both DRW and DRE compared with control group. Levels of AST, Creatine were significantly reduced in DRE group compared with control group. Moreover LDH showed only a tendency to increase in the DRW and DRE groups. Conclusions In summary, the present study showed that Dioscoreae Rhizoma improved in physical fatigue and exercise practice ability and DRE improved the superior than those of DRW.

• Korean Chemical Engineering Research
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• 제46권5호
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• pp.945-948
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• 2008

나노복합체는 높은 기계적 강도, 내열성, 그 밖의 많은 장점들로 인하여 첨가제에 따라 자동차, 우주항공 그리고 생체분야에 응용되어 사용되어지고 있다. 클로자이트(Cloisite) 15A 존재하의 에폭시 수지를 바탕으로 한 나노복합체를 합성하고 TEM, XRD, TGA, 그리고 DMA 등을 이용하여 분석하였다. 첨가제로 사용된 클레이의 층간간격(d-space)의 영향을 알아보기 위하여 클로자이트 20A 존재 하에서도 비슷한 나노복합체를 합성하였다. 나노복합체의 제조 시에 전통적으로 이용되어져온 핫플레이트와 자석을 이용한 제조법이외에도 초음파를 이용하여 나노복합체를 제조하였으나 두 경우 모두 나노복합체의 구조가 삽입형 구조를 얻어 구조면에서의 혼합의 영향이 없었다. 클레이가 존재하지 않았을 때에 비하여 5 wt%의 클로자이트 15A 존재 하에서 20분간 초음파로 혼합시의 복합체의 저장 탄성률이 10% 증가됨을 보였다. 일반적으로 클로자이트 15A 존재 하에서의 복합체가 클로자이트 20A 존재 하에서의 복합체보다 좋은 저장 탄성률을 보였다.

• 한국안전학회지
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• 제23권6호
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• pp.150-157
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• 2008

The purpose of this study was to investigate the effect of short-tenn stretching type of muscular strength gymnastics on health-related fitness and rating of perceived pain for automotive industry workers. The subjects selected were 27, who were divided into 3 groups(A group=10, B group=9, C group=8). Group A performed a short-term stretching Type of Muscular Strength Gymnastics only one time. Group B continuously performed the exercise program two times. Group C was a control group. The exercise program was a stretching Type of Muscular Strength Gymnastics, which was performed 3 times per week for 4 weeks. Its intensity was RPE 11-15. Data analysis was conducted by using SPSS ver 14.0. The test was conducted with two-way repeated ANOVA, post-hoc Ducan and paired t-test (a<.05). This study showed the following results. Muscular strength, muscular endurance and flexibility increased in all intra and between groups. Ratio of %fat decreased for group B but the control group presented conversely. Rating of perceived pain of group A decreased at arm and hands. Rating of perceived pain of group A decreased at back and leg.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.237.2-237.2
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• 2013

ReRAM cell, also known as conductive bridging RAM (CBRAM), is a resistive switching memory based on non-volatile formation and dissolution of conductive filament in a solid electrolyte [1,2]. Especially, Chalcogenide-based ReRAM have become a promising candidate due to the simple structure, high density and low power operation than other types of ReRAM but the uniformity of switching parameter is undesirable. It is because diffusion of ions from anode to cathode in solid electrolyte layer is random [3]. That is to say, the formation of conductive filament is not go through the same paths in each switching cycle which is one of the major obstacles for performance improvement of ReRAM devices. Therefore, to control of nonuniform conductive filament formation is a key point to achieve a high performance ReRAM. In this paper, we demonstrated the enhanced repeatable bipolar resistive switching memory characteristics by spreading the Ag nanocrystals (Ag NCs) on amorphous GeSe layer compared to the conventional Ag/GeSe/Pt structure without Ag NCs. The Ag NCs and Ag top electrode act as a metal supply source of our devices. Excellent resistive switching memory characteristics were obtained and improvement of voltage distribution was achieved from the Al/Ag NCs/GeSe/Pt structure. At the same time, a stable DC endurance (>100 cycles) and an excellent data retention (>104 sec) properties was found from the Al/Ag NCs/GeSe/ Pt structured ReRAMs.

• International Journal of Advanced Culture Technology
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• 제7권1호
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• pp.231-236
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• 2019

Background/Objectives: This paper proposes a dual mode feedback-controlled cycling system for children with spastic cerebral palsy to rehabilitate upper extremities. Repetitive upper limb exercise in this therapy aims to both reduce and analyze the abnormal torque patterns of arm movements in three- dimensional space. Methods/Statistical analysis: We designed an exercycle robot which consists of a BLDC motor, a torque sensor, a bevel gear and bearings. Mechanical structures are customized for children of age between 7~13 years old and induces reaching and pulling task in a symmetric circulation. The shafts and external frames were designed and printed using 3D printer. While the child performs active/passive exercise, angular position, angular velocity, and relative torque of the pedal shaft are measured and displayed in real time. Findings: Experiment was designed to observe the features of a cerebral palsy child's exercise. Two children with bilateral spastic cerebral palsy participated in the experiment and conducted an active exercise at normal speed for 3 sets, 15 seconds for each. As the pedal reached 90 degrees and 270 degrees, the subject showed minimum torque, in which the child showed difficulty in the pulling task of the cycle. The passive exercise assisted the child to maintain a relatively constant torque while visually observing the movement patterns. Using two types of exercise enabled the child to overcome the abnormal torque measured in the active data by performing the passive exercise. Thus, this system has advantage not only in allowing the child to perform the difficult task, which may contribute in improving the muscle strength and endurance and reducing the spasticity but also provide customizable system according to the child's motion characteristic. Improvements/Applications: Further study is needed to observe how passive exercise influences the movement characteristics of an active motion and how customized experiment settings can optimize the effect of pediatric rehabilitation for spastic cerebral palsy.

• 융합정보논문지
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• 제11권7호
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• pp.288-297
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• 2021

본 연구는 호스피스팀원을 대상으로 임종돌봄 수행의 중요도와 수행도 간의 차이를 조사하여 임종돌봄 프로그램 개발의 기초자료를 제공하고자 시도되었다. 2020년 12월 1일부터 2021년 2월 15일까지 총 6개 기관의 대학병원, 종합병원, 호스피스의료기관의 호스피스팀을 대상으로 127부의 자료를 분석하였고, 서술적 통계, 임상돌봄 수행 중요도와 수행도의 상호차이(Gap)는 paired t-test를 사용하였으며, 임상돌봄 수행 중요도와 수행도의 상호차이 결과분석은 IPA Matrix를 사용하였다. IPA Matrix로 분석한 결과 '신체간호'과 '심리간호'는 지속적으로 유지 강화해야하는 제1사분면 영역에 속하였고, '영적간호'는 장기적인 개선이 요구되는 제3사분면 영역으로 나타났다. 집중개선이 필요한 제2사분면에 속하는 것은 없는 것으로 나타났다. 본 연구결과를 토대로 호스피스팀의 임종돌봄 수행 교육프로그램 구성 시, 신체 및 심리간호는 계속적으로 유지 강화할 수 있는 전략과 영적간호에 대한 장기적인 개선전략 수립이 필요하다.