• Korean Chemical Engineering Research
• /
• v.43 no.2
• /
• pp.259-265
• /
• 2005

Binary isothermal vapor-liquid equilibrium(VLE) data were measured for water+n-methylformamide(NMF), benzene+NMF and toluene+NMF systems by using headspace gas chromatography(HSGC) at 353.15K. Additionally, the ternary liquid-liquid Equilibrium(LLE) data were determined by measuring of tie-line for the systems of NMF+benzene+n-heptane and NMF+toluene+n-heptane at 298.15 K. The measured isothermal binary VLE data have no azeotropes and were correlated well with $g^E$ model equations of Margules, van Laar, Wilson, NRTL and UNIQUAC. The experimental ternary tie line data were also correlated well with NRTL and UNIQUAC models. Besides their accuracy was analyzed by Hirata-Fujita and Maior-Swenson equations.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.2
• /
• pp.245-253
• /
• 2020

The present study is an experimental study to investigate the characteristics of strength by mixing polyaluminum chloride(PAC) with OPC-slag-FA ternary blended cement. There are three types of binders: 80% OPC + 10% slag + 10% FA, 60% OPC + 20% slag + 20% FA, and 40% OPC + 30% slag + 30% FA. PACs used 0, 2, 4, 6, 8, and 10% of the mixing-water weight. Experimental results show that PAC improves compressive strength regardless of the amount of OPC. PAC consumes portlandite, forms Friedel's salt, and reduces the diameter of the pores, making the matrix compact, contributing to the improvement of compressive strength. However, porous FA particles had an effect of delaying hydration by absorbing PAC in the initial hydration step. Therefore, the use of FA needs to determine the substitution rate in consideration of the hydration delay effect.

• Journal of Astronomy and Space Sciences
• /
• v.15 no.1
• /
• pp.183-196
• /
• 1998

The Synthetic Aperture Radar(SAR) image and the Digital Elevation Model(DEM) of an target area are put into use to generate three dimensional image map. An method of image map generation is explained. The orbit and attitude determination of satellite makes it possible to model signal acquisition configuration precisely, which is a key to mapping image coordinates to geographic coordinates of concerned area. An application is made to RADARSAT in the purpose of testing its validity. To determine the orbit, zero Doppler range is used. And to determine the attitude, Doppler centroid frequency, which is the frequency observed when target is put in the center of antenna's view, is used. Conventional geocoding has been performed on the basis of direct method(mapping image coordinates to geographic coordinates), but in this reserch the inverse method(mapping from geographic coordinates to image coordinates) is taken. This paper shows that precise signal acquisition modeling based on the orbit and attitude determination of satellite as a platform leads to a satellite-centered accurate geocoding process. It also shows how to model relative motion between space-borne radar and target. And the relative motion is described in ECIC(earth-centered-initial coordinates) using Doppler equation and signal acquisition geometry.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.25 no.5
• /
• pp.225-229
• /
• 2015

This study was performed to investigate crystal structure of cubic spinel-type monophase oxide composed of the Mn-Co-Ni ternary system. Starting material was prepared by mixing Mn, Co, Ni oxides then evaporation to dryness. The XRD patterns were analyzed by in-situ XRD as increasing temperature from room temperature to $1400^{\circ}C$ in air atmosphere. The cubic spinel phase was existed in a temperature range from $900^{\circ}C$. However, separation of NiO phase was detected from $1300^{\circ}C$, which was the origin of deterioration in the crytallinity. The surface morphology of the manufactured NTC thermistors were analyzed by FE-SEM for comparison of good and bad samples.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.30 no.4
• /
• pp.20-26
• /
• 1993

본 연구는 CSDP-선체 CAD 시스템 개발'4' 세부과제의 일환으로 수행되었으며 세부과제는 선체 구조 설계 기능을 전산화하기 위한 목표를 설정하고 CSDP 연구사업의 첫해년도부터 지금까지 4년간 수행하였다. 1차년도('88년∼'89년)에는 그 당시까지 단편적으로 개발된 구조설계 프로그 램을 통합하여 살물선 중앙부에 대해 선급규정에 의한 종강도 부재의 배치 및 치수결정 프로그 램을 개발하였다. 2차년도('89년∼'90년)에는 1차년도의 연구결과를 힁부재 및 힁격벽 부재까지 확장하여 살물선 중앙부의 종강도 부재, 힁격벽 부재의 배치 및 치수결정 프로그램을 개발하여 살물선 중앙부의 구조설계를 지원하는 프로그램을 완성하였다. 3차년도('91년∼'92년)에는, 이 중선각 유조선에 대한 관심이 고조되고 있는 바, 동 세부과제에서도 조선소의 요구에 따라 대상 선박을 살물선에서 이중선각 유조선으로 확장하고, 기존의batch방식을 대화식으로 교체하여 선급규정(DnV, L1oyd)에 의한 종강도 부재의 설계 기능과, 간이 해석에 의한 대화식 이중선각 유조선 중앙부의 구조배치 및 치수결정 기능을 갖는 프로그램(ISSMID_T)을 개발하였다. 당해 연도인 4차년도에는, 3차년도까지 개발한 프로그램의 기능, 성능을 보완 확장하였고, 또한 조선 전용 선체 CAD시스템(AUTOKON)과의 Interface도 삼성중공업과 공동으로 개발하였다.

• Journal of the Korean Ceramic Society
• /
• v.33 no.8
• /
• pp.895-900
• /
• 1996

Ba(Ti1-xSnx)4O9 powder was synthesized by oxalate method. With the substitution of Sn into Ti site the sintered BaTiO4 crystal phase was stabilized due to the formation of solid solution. The optimal amounts of Sn solutbility for formation of BaTi4O9 crystalline phase was 0.16mole and of Sn was substituted and sintering was done at 135$0^{\circ}C$ for 30 minutes long rod type crystal was well developed and the highest Q value was obtained. But dielectric constant wasnearly constant without regarding to the Sn addition and the sintering time.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.4 no.3
• /
• pp.238-244
• /
• 1994

We investigated solution growth of silicon on borosilicate and quartz glass substrates in the temperature range of $800^{\circ}C~520^{\circ}C$. A thin Al-Si layer evaporated onto the substrate serves to improve the wetting between the substrate and the Al/Ga solvent. Nucleation takes place by a reaction of Al with $SiO_2$ from the substrate. We obtained silicon deposits with a grain size up to a few 100 $\mu\textrm{m}$. There was a perferential (111) orientation for the case of quartz glass substrates while there is a strong contribution of other orientations for the deposition of Si on borosilicate glass substrates.

• Korean Journal of Clinical Laboratory Science
• /
• v.51 no.2
• /
• pp.198-204
• /
• 2019

Various treatments can be attempted in patients with intractable epilepsy, in whom the symptoms of seizures are not controlled by various drugs. On the other hand, in patients requiring a surgical method, a preoperative examination is needed to determine the portion of seizure site to be resected. Electrodes are inserted into the cerebral cortex for accurate lesion measurements and safe operation. The electrodes inserted in the cortex not only record the electroencephalography (EEG), but also allow various tests to confirm the function of the part. One of these methods is the evoked potential test. From January 2015 to December 2018, the trends of measured waveforms in were analyzed 70 patients. The somatosensory evoked potential (SSEP) recorded on the electrode inserted in the cerebral cortex can be searched for the pathway of the central sulcus to avoid the primary motor area and primary sensory area. In addition, using the middle latency auditory evoked potentials (MLAEP) and flash visual evoked potentials (FVEP), the functional cortex in the auditory cortex and the visual cortex were compared with the seizure focus point on the EEG to help determine the location of the ablation and minimize functional impairment after surgery.

• Journal of the Mineralogical Society of Korea
• /
• v.28 no.2
• /
• pp.127-133
• /
• 2015

Li-bearing muscovite is commonly found along with trioctahedral lepidolite in granitic pegmatites. Structurally, $Li^+$ ions can replace $K^+$ ions in the interlayer (Int) of muscovite or incorporate into vacancies of the dioctahedral sheet (Sub). However, detailed mechanism of the lithium incorporation into muscovite is challenging to investigate using experimental techniques alone. In the current study, density functional theory (DFT) has been applied to examine the crystal structure and energy variation when $Li^+$ resides in the interlayer or the octahedral sheet. Depending on the position of $Li^+$ (i.e., Int vs. Sub), DFT showed significant differences in the mica's structures such as lattice parameters, sheet thickness, interlayer separation, and OH angles with respect to the ab plane. DFT further showed that, in pure muscovite, $Li^+$ has a lower energy when it is located in Int than Sub. By contrast, in the case of $Fe^{2+}$ substitution into the octahedral sheet, $Li^+$ has a lower energy in Sub than in Int. These results imply that $Li^+$ incorporates into the Al octahedral sheets only when the octahedral sheets possess structural charges, suggesting cation substitution in the octahedral sheets plays an important role in the Li incorporation mechanism into muscovite. They can also explain the experimental observation about the positive relationship between $Fe^{2+}$ and $Li^+$ amounts in Li-bearing muscovite.

• 한국노년학
• /
• v.38 no.3
• /
• pp.501-519
• /
• 2018

The purpose of this study was to explore perception about shared decision making of family caregivers of patients with early dementia (PWED). This study was conducted with a sample of 12 family caregivers (mean age = $71.4{\pm}10.4$) of PWED from three dementia safety centers in Seoul. In-depth interviews were done for each participant about shared decision making and data were analyzed using qualitative content analysis. Six categories and 17 sub-categories identified for participants' perception about shared decision making: means to facilitate communication with patients with dementia, means to secure autonomy of patients, opportunity to facilitate treatment, cause of increasing family caregivers' burden, cause of worsening relationship with patients, and option for choices depending on priority change. The findings of this study can provide a knowledge basis for health care professionals and policy makers to understand how family caregivers of PWED think about shared decision making. It would be of great value to develop educational programs and practical guidelines about shared decision making for PWED and their family, which may contribute to respecting PWED's self-determination right as well as reducing burden of their family.