• Archives of Pharmacal Research
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• 제7권2호
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• pp.115-120
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• 1984

The crystals of bromhexine-HCl, $C_{14}$ H$_{21}$ N$_{2}$Br$_{2}$Cl, are orthohombic, space group Pca2 with a = 14.598(2)A, b=12.461(3)A, c =9 9.186(1) A and Z = 4. Intensity dat for 967 reflections (Fobs > 6.sigma.(F)) were collected on a Rigaku-Denki automatic four circle diffractometer. The structure was solved by the Patterson and Fourier methods. Refinements were carried out to the final R value of 0.082. The cyclohexane ring has a normal chair form and the benzene ring is planar. There are three independenet hydrogen bounds in the structure. One is an intermolecular hydrogen bond (N-H... Cl) and the others are intramolecular hydrogen bonds (N-H...Br, N$^{+}$-H...Cl$^{[-10]}$ ) Apart from the hydrogen bounding system the molecules are held together in the crystal by van der Waals force.e.

• 한국세라믹학회지
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• 제12권3호
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• pp.8-12
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• 1975

The crystal structure of synthetic magnesite has been studied by X-ray method. Magnesite is trigonal R3c, with a=4.637$\AA$, c=15.023$\AA$ and Z=6. Intensity data were collected with a Rigaku automated four-circle diffractometer and Mo-K$\alpha$ radiation. The structure was refined by the full-matrix least squares method using anisotropic thermal parameters. The final R index for 234 reflections is 0.037. The C-O and Mg-O bond lengths were 1.283 and 2.105$\AA$, respectively. The interatomic angles of three kinds of O-Mg-O were 88.25, 91.75 and 180.00$^{\circ}$, respectively. It is clarified that the distortion of the Mg-O6 octahedron in magnesite is smaller than that of Ca-O6 in calcite.

• Structural Engineering and Mechanics
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• 제14권6호
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• pp.649-660
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• 2002

Experimental results are presented from tests conducted on reinforced concrete beam-column joints with lap splices under reversed cyclic loading simulating earthquake action. Response curves are compared for twenty-four specimens designed according to Eurocode 2. The main parameters of the investigation are, the geometry of the reinforcing bar extension, the applied axial load (normalized), the available cover over lap splice region extended as length required from Eurocode 2, as well as the shape and the volumetric percentage of the stirrups confining the lap splice zone. The results are evaluated with regards to the load intensity, the energy absorption capacity and the characteristics of the load deflection curve.

• KDI Journal of Economic Policy
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• 제44권3호
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• pp.49-74
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• 2022

This paper empirically examines how fiscal instability affects financial instability. According to an IMF forecast (2021a), the fiscal space in Korea will be steadily reduced in the future. The theoretical literature predicts that if fiscal stability is undermined, financial stability will also be in danger given that government guarantees on banks are weakened and/or sovereign bonds held in banks become riskier. This paper empirically finds the existence of this negative impact of fiscal instability on financial instability. I also find that the intensity of this fiscal-financial relationship is greater in a country where (i) its currency is not a reserve currency such as the US dollar or euro, (ii) its banking sector is large relative to government sector, and/or (iii) its private credit to GDP is high. Korea has all of these three characteristics and hence needs to put more effort into maintaining fiscal stability.

• 한국의류학회지
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• 제40권6호
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• pp.1010-1024
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• 2016

This study identifies the influence of on/off-line acquaintances' recommendation messages on fashion product attitude and purchase intention on the online purchase of fashion products in two-sided word of mouth situations as well as compares the difference in influence according to bond-base with equidistance. This study was conducted for one month on university students in their 20s who were believed to be active in smartphone use. Out of the collected 174 copies of the questionnaire, 162 copies were used for analysis. The questionnaire was classified into online and offline recommendation messages of an acquaintance. We present two-sided fashion product reviews made similar to the type found in an actual shopping mall web-site. As for analysis, confirmatory factory analysis, structural equation modeling, and multi-group analysis were conducted using AMOS 19.0. The analysis results are as follows. First, on/off-line acquaintances' recommendation messages had significant influences on product attitude in the situation where two-sided reviews on fashion products were presented; however, those messages did not influence purchase intention. Recommendation messages positively increased product attitude and enhanced purchase intention if acquaintances' recommendation messages were mediated between on/off-line acquaintances' recommendation messages and purchase intention. Consequently, a mediating effect on product attitude was revealed. Second, there was no difference between online acquaintances and offline acquaintances in terms of the influence of acquaintances' recommendation messages on product attitude and purchase intention, in the situation where two-sided reviews were presented on online fashion products. Therefore, no control effect according to the type of acquaintance was confirmed.

• Bulletin of the Korean Chemical Society
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• 제14권6호
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• pp.713-717
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• 1993

The crystal structure of the potassium salt of penicillin V has been studied by the X-ray crystallographic methods. Crystal data are as follows; potassium 3,3-dimethyl-7-oxo-6-phenoxyacetoamido-4-thia-1- azabicyclo[3.2.0]-heptane-2${\alpha}$-carboxylate, $K^+{\cdot}C_{16}H_{18}N_2O_5S^-$, $M_r$= 388.5, triclinic, Pl, a= 9.371 (1), b= 12.497 (2), c= 15.313 (2) ${\AA},\;{\alpha}= 93.74\;(2),\;{\beta}=99.32\;(1),\;{\gamma}=90.17\;(1)^{\circ},\;V=1765.7\;(2)\;{\AA}^3$, Z=4, $D_m=1.461\;gcm^{-1},\;{\lambda}(Cu\;K{\alpha})=1.5418\;{\AA},\;{\mu}=40.1\;cm^{-1}$, F(000)=808, T=296 K. The structure was solved by the heavy atom and difference Fourier methods with intensity data measured on an automated four-circle diffractometer. The structure was refined by the full-matrix least-squares method to a final R= 0.081 for 3563 observed $[I_0{\geq}2{\sigam}(I_0)]$ reflections. The four independent molecules assume different overall conformations with systematically different orientations of the phenyl groups although the penam moieties have the same closed conformations. There are intramolecular hydrogen bonds between the exocyclic amide nitrogen and phenoxy oxygen atoms. The penam moiety is conformationally very restricted although the carboxyl and exocyclic amide groups apparently have certain rotational degrees of freedom but the phenyl group is flexible about the ether bond despite the presence of the intramolecular N-H${\cdots}$O hydrogen bond. There are complicated pseudo symmetric relationships in the crystal lattice. The penam moieties are related by pseudo 20.5 screw axes and the phenyl groups by pseudo centers of symmetry. The potassium ions, related by both pseudo symmetries, form an infinite zigzag planar chain parallel to the b axis. Each potassium ion is coordinated to seven oxygen atoms in a severely distorted pentagonal bipyramid configuration, forming the infinite hydrophilic channels which in turn form the molecular stacks. Between these stacks, there are only lipophilic interactions involving the phenyl groups.

• 기술혁신연구
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• 제26권4호
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• pp.173-198
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• 2018

본 연구는 세계 42개국의 자료를 사용하여 산업용 로봇 도입의 결정요인을 분석하고, 한국에서 산업용 로봇이 빠르게 확산되고 있는 원인을 진단하였다. 산업용 로봇 변수는 국제로봇협회(IFR)의 2001년-2016년 "World Robotics: Industrial Robots" 자료를 사용하였다. 설명변수는 노동시장환경 변수와 혁신역량 변수를 포함하며, 관련 변수들은 해당 국제기관들의 자료에서 추출하였다. 실증분석에는 일부 설명변수의 내생성을 통제하기 위해 Arellano-Bond 동적 패널분석을 사용하였다. 분석결과, 한국은 소득수준이나 고용비용 및 혁신역량 등을 고려하더라도 다른 국가들에 비해 산업용 로봇 도입이 매우 빠르게 확대되어 온 것을 확인할 수 있었다. 이는 수요 측면과 공급 측면 모두에서 그 원인을 찾을 수 있다. 즉, 고용비용 증가 등의 노동시장환경 변화가 산업용 로봇 도입에 대한 기업 수요를 견인하였으며, 경제 전반의 자본집약도 증가와 기업의 혁신역량 증대와 같은 공급 측면 요인 또한 산업용 로봇의 도입을 촉진시켰다.

• 한국진공학회지
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• 제8권1호
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• pp.63-69
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• 1999

고밀도 플라즈마 source인 helical resonator의 특성을 알기 위해 Langmuir probe를 사용하여 특성 변수들-플라즈마 밀도, 전자 온도, 이온 전류 밀도-의 값을 측정하였다. 또한 $Cl_2$/poly-Si 시스템에서의 식각반응 메카니즘을 규명하기 위해 Si와 SiCi의 에미션 시그날을 분석하였다. $Cl_2$/poly-Si 식각 시스템계에서는 화학식각에 의한 반응이 물리식각에 의한 반응보다 주됨을 알 수 있다. 또한 폴리 실리콘 내의 불순물 P농도가 증가함에 따라 식각의 화학반응 산출물인 SiCl의 양이 물리식각 산출물인 Si의 양보다 급격히 증가하는 양상을 보였다. 이는 표면 반응중 형성된 Si-Cl 결합을 통해 실리콘 내부의 전자들이 Cl쪽으로 이동함으로써 Si-Cl은 더욱 유동적이며 이온화된 특성을 갖게 되고, 따라서 $Cl_2\;^+$/와 같은 에천들이 표면에 흡착될 확률이 커져 $SiCl_x$의 형성을 용이하게 하기 때문으로 생각된다. 즉 불순물 P농도가 증가함에 따라 표면의 Si를 제거하는데는 물리식각보다 화학시각이 더욱 큰 역할을 하는 것으로 밝혀졌다.

• 대한화학회지
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• 제48권3호
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• pp.229-235
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• 2004

고에너지 화합물의 수소결합 현상을 연구하기 위하여 nitromethane 단량체 (monomer)와 이합체 (dimer)에 대하여 Gaussian-98 프로그램을 사용하여 restricted BLYP/6-311++G(d,p), B3LYP/6-311++G(d,p), MP2/6-311++G 계산을 수행하였다 . 이러한 이론적 연구를 통하여 nitromethane 단량체 및 이합체의 구조와 수소결합 및 진동스펙트럼을 구하였다 . 본 연구의 결과 nitromethane 상온에서 분자 간에 두 개의 수소결합을 이루며 이합체를 형성하는 것이 유리하고 , 이 이합체는 단량체보다 BLYP, B3LYP, MP2 level 계산에서 각각 약 15.2, 19.4, 32.6 kJ/mol 만큼 안정화됨을 알 수 있었다.

• 자원리싸이클링
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• 제18권6호
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• pp.30-37
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• 2009

소디움실리케이트 수용액으로부터 나트륨이온이 제거된 핵생성 산화실리케이트 수용액과 실리케이트 수용액을 pH 10~11로 조절하여 혼합한 다음, $20{\sim}80^{\circ}C$에서 솔-젤 반응하여 실리카 솔 입자를 제조하였다. 이 때 yellow silicomolybdate method를 이용하여 소디움실리케이트와 나트륨이온이 제거된 실리케이트 수용액의 특성과 이들 출발용액으로부터 솔-젤 반응에 의해 제조된 실리카 솔의 입자특성에 대하여 고찰하였다. $SiO_2$를 2 wt% 함유한 소디움실리케이트 수용액은 약 95% 이상의 반응성 실리케이트를 함유하며, 솔-젤 반응에 참여하는 반응성 실리케이트는 전체 실리카 기준 약 50% 정도이다. 반응온도가 증가함에 따라 silanol(Si-OH) 결합구조의 흡수피크 세기는 감소하고, siloxane(Si-O-Si) 결합구조의 흡수피크 세기가 증가하였다. 반응조건별로 제조된 실리카 솔 수용액의 zeta potential은 -40~-60 mV 범위로 분산성이 좋은 상태를 유지하였다. 실리카 솔 입자크기는 5~10 nm로 반응온도 증가에 따라 크기가 약간 감소하였다. 실리카 솔 제조 후, 2차 입자 성장을 위하여 실리케이트 수용액을 재 첨가하였을 경우에 실리카 솔입자 크기가 약 20 nm로 증가하였다.