• Bulletin of the Korean Chemical Society
• /
• 제35권1호
• /
• pp.253-256
• /
• 2014

Functionalization of zigzag graphene nanoribbon (ZGNR) segment containing 120 C atoms with pyridine (3NV-ZGNR) defects was investigated on the basis of density-functional theory (DFT) calculations, results show that edge-modified ZGNRs by Sc can adsorb multiple hydrogen molecules in a quasi-molecular fashion, thereby can be a potential candidate for hydrogen storage. The stability of Sc functionalization is dictated by a strong binding energy, suggesting a reduction of clustering of metal atoms over the metal-decorated ZGNR.

• 한국분말재료학회지
• /
• 제16권5호
• /
• pp.336-341
• /
• 2009

To produce alloy powders with only Sm$_2$Fe$_{17}$ single phase by reduction-diffusion (R-D) method, the effect of excess samarium oxide on the preparation of Sm-Fe alloy powder during R-D heat treatment was studied. The quantity of samarium oxide was varied from 5% to 50% whereas iron and calcium were taken 0% and 200% in excess of chemical equivalent, respectively. The pellet type mixture of samarium, iron powders and calcium granulars was subjected to heat treatment at 1100$^{\circ}C$ for 5 hours. The R-D treated pellet was moved into deionized water and agitated to separate Sm-Fe alloy powders. After washing them in deionized water several times, the powders were washed with acetic acid to remove the undesired reaction products such as CaO. By these washing and acid cleaning treatment, only 0.03 wt% calcium remained in Sm-Fe alloy powders. It was also confirmed that the content of unreacted $\alpha$-Fe in Sm$_2$Fe$_{17}$ matrix gradually decreased as the percentage of samarium oxide is increased. However, there was no significant change above 40% excess samarium oxide.

• 한방재활의학과학회지
• /
• 제28권2호
• /
• pp.91-104
• /
• 2018

Objectives The aim of this study is to investigate the effect of Acupotomy on the pain reduction and functional improvement of patients with Acute low back pain. Methods We studied 60 patients with Acute low back pain with Numeric Rating Scale (NRS) 5 or higher in admission and had admitted to Department of Korean Medicine Rehabilitation of Daejeon University from March 1, 2017 to October 31, 2017. 30 patients had received Acupotomy combined Korean Medicine treatment(such as acupuncture, moxabustion, herbal medicine, etc) and the other 30 had received Korean Medicine treatment only. The analysis was conducted as a retrospective study which analyzes the patient's medical records. Statistical analysis was performed using the IBM SPSS Statistics 24 program. We used NRS to evaluate pain reduction, used Range of Motion (ROM) and Roland Morris Disability Questionnaire (RMDQ) to evaluate function improvement, and used EuroQol-5 Dimension (EQ-5D) and EuroQoL-Visual Analogue Scale (EQ-VAS) to assess quality of life. Finally, a five-point Likert scale was used to assess treatment satisfaction. Results The analysis revealed that patients who were treated with Acupotomy showed statistically significant NRS reduction, improvement of ROM and RMDQ, improvement of EQ-5D and EQ-VAS and satisfaction compared to those who just recevied Korean Medicine treatment. Conclusions In conclusion, we found that the Acupotomy showed a positive effect on pain resolving, functional rehabilitation and quality of life in patients with Acute low back pain.

• 한국식품과학회지
• /
• 제39권2호
• /
• pp.152-157
• /
• 2007

해조성분 강화 기능성소금 3종(Hizikia mineral salt, fucoidan salt, laver salt)을 제조하여 일반적 품질특성 및 무기성분 조성, 용해도, 관능특성 및 ACE 저해활성과 bile acid 결합력을 알아보았다. 수분함량은 Hizikia mineral salt의 경우 대조시료와 유의한 차이가 없었으나 fucoidan salt와 laver salt는 상대적으로 높은 수분함량을 나타내었다. 염도는 해조성분 강화 기능성소금 3종 모두 대조시료 보다는 약간 낮은 값을 나타내었고 pH는 Hizikia mineral salt의 경우 11.34로 다소 높은 값을, fucoidan salt와 laver salt은 6.88과 6.53으로 중성에 가까운 값을 나타내었으며, ORP는 -229 mV에서 38 mV로 월등히 낮은 값을 나타내었다. 기능성 소금의 L, a, b 값은 모두 정제염 보다는 약간 어두운색을 나타내었다. 무기물 함량은 Hizikia mineral salt에서 혈압 저하에 효과가 있는 무기성분인 $K^{+}$ 함량이 다량 함유되어 있었으며 용해도는 Hizikia mineral salt가 다소 떨어지는 경향을 나타내었으나 큰 차이는 나타나지 않았다. 관능특성을 알아본 결과 $Na^{+}$ 이외의 미네랄 성분을 다량 함유하고 있는 Hizikia mineral salt를 제외한 나머지 fucoidan salt, laver salt에서는 색을 제외한 모든 항목에서 높은 점수를 받아 조미기능성 염으로서도 사용가치가 기대되었다. 또한, laver salt는 54.8% 수준의 ACE 저해 활성값을 나타내었으며, fucoidan salt는 54.1-80.7% 수준의 높은 bile acid 결합특성을 각각 나타냄으로서 콜레스테롤 대사 및 혈압조절 기능성을 갖고 있는 것으로 사료되었다.

• 벤처창업연구
• /
• 제7권4호
• /
• pp.143-148
• /
• 2012

기업들이 제품을 개발하는데 가치공학을 적용하여 실시할 때 느끼는 공통적인 어려움은 기능을 어떻게 정확하게 정의하느냐가 관건인 것으로 나타났다. 기능이라는 추상적인 개념을 어떻게 수치화하느냐에 따라 가치공학의 효과가 차이가 나기 때문이다. 더 나아가 가치공학의 성과를 향상시키기 위해서는 가치의 향상이 요구되어지는데 가치공학을 실시하고 있는 대부분의 기업들은 원가절감에 목적을 두고 이 방법을 추진하고 있다. 제품 개발의 연구결과 기능은 충족하면서 본체, 노트북, 부루투스 프로브가 제품에 대부분을 차지하는 것을 확인할 수 있으며, 원가절감을 위해서는 안정된 품질이 요구되는 것과 맞추어 구매에서의 원가 절감노력이 필요하다고 사료되며 구매업체의 다변화를 통한 가격다운 절감노력이 필요한 것으로 분석, 연구되었다.

• Bulletin of the Korean Chemical Society
• /
• 제4권1호
• /
• pp.3-9
• /
• 1983

Lithium n-butylborohydride was prepared from borane-dimethylsulfide (BMS) and n-butyllithium, and the approximate rates and stoichiometrics of its reactions with selected organic compounds containing representative functional groups were studied in THF at room temperature. Phenol and benzenetiol liberated hydrogen quickly and quantitatively, and the reactions of primary alcohols, 2,6-di-ter-butylphenol and 1-hexanethiol liberated hydrogen quantitatively within 3 hrs, whereas the reactions of secondary and tertiary alcohols were very slow. Aldehydes and ketones were reduced rapidly and quantitatively to the corresponding alcohols. Cinnamaldehyde utilized 1 equiv. of hydride rapidly, suggesting the reduction to cinnamyl alcohol. Carboxylic acids evolved 1 equiv. of hydrogen rapidly and further reduction was not observed. Anhydrides utilized 2 equiv. of hydride rapidly but further hydride uptake was very slow, showing a half reduction. Acid chlorides were reduced to the alcohol stage very rapidly. All the esters examined were reduced to the corresponding alcohol rapidly. Lactones were also reduced rapidly. Expoxides took up 1 equiv. of hydride at a moderate rate to be reduced to the corresponding alcohols. Nitriles and primary amides were inert to this hydride system, whereas tertiary amide underwent slow reduction. Nitroethane and nitrobenzene were reduced slowly, however azobenzene and azoxybenzene were quite inert. Cyclohexanone oxime evolved 1 equiv. of hydrogen rapidly, but no further reduction was observed. Phenyl isocyanate and pyridine N-oxide were proceeded slowly, showing 1.74 and 1.53 hydride uptake, respectively in 24 hours. Diphenyl disulfide was reduced rapidly, whereas di-n-butyl disulfide, sulfone and sulfonic acids were inert or sluggish. n-Hexyl iodide and benzyl bromide reacted rapidly, but n-octyl bromide, n-octyl chloride, and benzyl chloride reacted very slowly.

• Bulletin of the Korean Chemical Society
• /
• 제15권2호
• /
• pp.132-138
• /
• 1994

Bis(diethylamino)aluminum hydride was utilized in a systematic study of the approximate rates and stoichiometry of the reaction of excess reagent with 55 selected organic compounds containing representative functional groups under standardized conditions (THF, $0^{\circ}C$, reagent to compound=4 : 1) in order to define the characteristics of the reagent for selective reductions. The reducing action of BEAH was also compared with that of the parent aluminum hydride. The reducing action of the reagent is quite similar to that of aluminum hydride, but the reducing power is much weaker. Aldehydes and ketones were readily reduced in 1-3 h to the corresponding alcohols. However, unexpectedly, a ready involvement of the double bond in cinnamaldehyde was realized to afford hydrocinnamyl alcohol. The introduction of diethylamino group to the parent aluminum hydride appears not to be appreciably influential in stereoselectivity on the reduction of cyclic ketones. Both p-benzoquinone and anthraquinone utilized 2 equiv of hydride readily without evolution of hydrogen, proceeded cleanly to the 1,4-reduction products. Carboxylic acids and acid chlorides underwent reduction to alcohols slowly, whereas cyclic anhydrides utilized only 2 equiv of hydride slowly to the corresponding hydroxylacids. Especially, benzoic acid with a limiting amount of hydride was reduced to benzaldehyde in a yield of 80%. Esters and lactones were also readily reduced to alcohols. Epoxides examined all reacted slowly to give the ring-opened products. Primary and tertiary amides utilized 1 equiv of hydride fast and further hydride utilization was quite slow. The examination for possibility of achieving a partial reduction to aldehydes was also performed. Among them, benzamide and N,N-dimethylbenzamide gave ca, 90% yields of benzaldehyde. Both the nitriles examined were also slowly reduced to the amines. Unexpectedly, both aliphatic and aromatic nitro compounds proved to be relatively reactive to the reagent. On the other hand, azo- and azoxybenzenes were quite inert to BEAH. Cyclohexanone oxime liberated 1 equiv of hydrogen and utilized 1 equiv of hydride for reduction, corresponding to N-hydroxycyclohexylamine. Pyridine ring compounds were also slowly attacked. Disulfides were readily reduced with hydrogen evolution to the thiols, and dimethyl sulfoxide and diphenyl sulfone were also rapidly reduced to the sulfides.

• 한국환경농학회지
• /
• 제18권4호
• /
• pp.349-354
• /
• 1999

본 연구에서는 기능성 가공식품에서의 농약 잔류기준 설정방법을 제안하고 그 기준안을 제시하고자 하였다. 이를 위해 농약성분의 감소계수를 추정하는 한편 기준설정을 위해 요구되는 감안인자 및 적용방법을 고안하였고 그에 근거하여 기준안을 제안하였다. 그 결과는 다음과 같다. 유기인계 농약의 조리 가공에 의한 제거율 데이타를 총정리한 결과 감소계수는 식품의수세-0.55, 세제에 의한 세척-0.44, 과일의 껍질 벗기기-0.99, 채소의 데치기 및 삶기-0.49, 곡류의 도정-0.24, 곡류의 조리 가공-0.40, 식품의 통조림-0.21, 김치발효-0.32, 포도주 발효-0.23(유기인계 이외의 농약 포함), 착유-정제-1.60(유기인계 이외의 농약 포함), 감귤류 과피에서 식이섬유 및 bioflavonoid 분리과정-0.03, 0.09로 추정되었다. 감귤과피에서 추출, 정제된 식이섬유 및 bioflavonoid 제품중 농약잔류 기준으로는 과실 자체에서의 잔류기준, 농약성분의 감소계수, 제품의 소비량을 감안하여 18가지 유기인계 농약에 대한 기준 시안을 제시하였다. 식이섬유 제품에서의 농약잔류 농도는 과피에서의 17.6%에 해당하므로 그 제품중 농약 잔류 기준을 과실 기준의 0.65배로 하여 산정한 기준안은 0.01-3.0mg/Kg이었다. Bioflavonoid 제품에서의 농약잔류 농도는 과피에서의 450%에 해당하므로 그 제품중 농약잔류 기준을 과실 기준의 16배로 하여 산정한 기준안은 0.1-80mg/Kg이었다.

• 대한환경공학회지
• /
• 제38권5호
• /
• pp.242-248
• /
• 2016

연료전지에서의 전체 반응 속도는 산화전극에서 일어나는 수소산화반응에 비해 그 반응 속도가 현저히 느린 환원전극에서의 산소환원반응(oxygen reduction reaction, ORR)에 의해 결정된다. ORR 효율성 평가를 용이하게 하는 지표(descriptor)로서 촉매 표면에서의 산소원자 흡착강도를 활용하는데, 산소흡착강도는 촉매 표면의 기하학적 구조 변형에 따른 전자구조를 변형함으로써 조절할 수 있다. 이에 본 연구에서는 백금 표면의 원자모델을 이용하여 표면의 기하학적 구조가 산소흡착강도에 미치는 영향과 그 원인을 밀도범함수이론(density functional theory, DFT) 계산을 통해 분석하였다. 먼저, 기하학적 구조를 인위적으로 변형시킨 Pt(111) 표면에서의 산소흡착반응을 밀도범함수이론 계산을 이용해 분석함으로써 기하학적 구조변화가 산소흡착강도에 미치는 영향(strain effect)을 확인하였다. 최적화한 Pt 격자상수($3.977{\AA}$)에 ${\pm}1%$ 간격의 변화율을 적용하고 각 변화율마다의 산소흡착강도를 계산하였는데, Pt-Pt 원자 간 거리가 멀어질수록 산소흡착강도가 강해지는 것을 확인하였다. 이는 원자 간 거리가 증가할수록 d-band center가 페르미 준위(Fermi level)쪽으로 이동하게 되며, 이로써 일부 반결합 오비탈(anti-bonding orbitals)에 전자가 채워지지 않기 때문에 전체적으로 반결합 오비탈이 형성될 가능성이 적어지기 때문이다. 결과적으로, 순수한 백금이 가진 격자상수($3.9771{\AA}$) 보다 약 2~4% 작은 백금 표면 격자크기를 가질 수 있도록 유도할 수 있다면 산소흡착강도가 적절히 약하게 조절될 수 있으며, 이는 순수한 백금보다 더 향상된 ORR 성능을 가진 촉매물질 개발 연구를 위한 기초자료로서 활용할 수 있을 것이다.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제36권1호
• /
• pp.30-36
• /
• 2014

There are many treatment options in management of mandibular condylar neck fractures. Closed reduction is the most conservative treatment; however, achievement of anatomic reduction is difficult, and there are some risks of mandibular functional impairment. Open anatomic reduction and internal fixation have some advantages; therefore, many oral and maxillofacial surgeons have attempted to achieve anatomic reduction through the open approach and extracorporeal reduction and fixation. However, when using this method, there is some risk of resorption of the fractured mandibular condylar head. Therefore, we designed a modified extracorporeal reduction technique, without detaching the lateral pterygoid muscle in order to maintain the blood supply to the fractured mandibular condylar head. We believe that this minor modification may minimize the risk of resorption of the fractured mandibular condylar head. In this article, we introduce this technique in detail, and report on two cases.