• 제목/요약/키워드: crystal analysis

검색결과 2,018건 처리시간 0.029초

The Crystal Structure of Acemetacin Monohrdrate $(C_{21}H_{18}NO_6Cl-H_2O)$, A Non-Steroidal Antiinflammatory Agent

  • Kim, Yang-Bae;Kim, Jeong-Ae;Park, Yeong-Il
    • Archives of Pharmacal Research
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    • 제16권2호
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    • pp.134-139
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    • 1993
  • The molecular structure of acemetacin, 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid carboxymethyl ester, was determined by single cystal X-ray diffraction analysis. The compound was recrystallized from a mixture of acetone and water in triclinic, space group P1, with a=7.796(1), b=10.245(2), c=13.542(3)$\AA,\;\alpha=97.35(1),\;\beta=96.34(1),\;\gamma=107.06(1)^\circ$, and Z=2. The calculated density is 1.422; the observed value is $1.42\;g/cm^3$. The structure was solved by the direct method and refined by full matrix least-squares procedure to the final R value of 0,037 for 2960 independent reflections. There are water molecules, which are thought to be co-crystallized during the evaporation procedure, with the ratio of one water per compound molecule in the crystal. The conformation of the compound is found to be very similar to that of indomethacin. The molecules are stabilized by three O-H.....O type intermolecular hydrogen bonds between the oxygen of water molecule and those of the compound.

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브러쉬 코팅 공정을 이용한 용액 기반 BiAlO 박막의 제작과 액정 소자에의 응용 (Fabrication of the Solution-Derived BiAlO Thin Film by Using Brush Coating Process for Liquid Crystal Device)

  • 이주환;김대현
    • 한국전기전자재료학회논문지
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    • 제34권5호
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    • pp.321-326
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    • 2021
  • We fabricated BiAlO thin film by a solution process with a brush coating to be used as liquid crystal (LC) alignment layer. Solution-processed BiAlO was coated on the glass substrate by brush process. Prepared thin films were annealed at different temperatures of 80℃, 180℃, and 280℃. To verify whether the BiAlO film was formed properly, X-ray photoelectron spectroscopy analysis was performed on Bi and Al. Using a crystal rotation method by polarized optical microscopy, LC alignment state was evaluated. At the annealing temperature of 280℃, the uniform homogenous LC alignment was achieved. To reveal the mechanism of LC alignment by brush coating, field emission scanning electron microscope was used. Through this analysis, spin-coated and brush coated film surface were compared. It was revealed that physical anisotropy was induced by brush coating at a high annealing temperature. Particles were aligned in one direction along which brush coating was made, resulting in a physical anisotropy that affects a uniform LC alignment. Therefore, it was confirmed that brush coating combined with BiAlO thin film annealed at high temperature has a significant potential for LC alignment.

보석용 루비의 가치평가 요소와 그 시장가격의 관련성 (The relations of appraising element and market prices in ruby being used for the jewelry)

  • 김상기;김판채
    • 한국결정성장학회지
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    • 제14권4호
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    • pp.169-173
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    • 2004
  • 보석용 루비의 가치평가 요소와 그 시장가격의 관련성을 분석하기 위하여 루비의 주요 평가요소인 중량, 색. 투명도 및 처리여부에 따른 가격의 변화를 Palmieri's Market Monitor를 이용하여 분석하였다. 그 결과 루비의 가치평가 요소가 복합적으로 기여하여 그 시장가격을 형성하고 있으며, 가치평가 요소 가운데에서 중량에 의한 가격 상승률이 가장 높고, 그 다음이 색이며, 투명도에 의한 가격 상승률은 가장 낮다는 것과 또한 열처리되지 않은 미얀마 루비는 열처리된 루비에 비해 가격 상승률이 더 높다는 것을 알 수 있었다.

Synthesis and Crystal Structures of Zn(II)- and Mn(II)- Diphenyldicarboxylate Complexes with N-Donor Ligand

  • Koo, Bon Kweon
    • 대한화학회지
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    • 제60권5호
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    • pp.321-326
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    • 2016
  • Two new polymeric complexes, [Zn(dpa)(pyz)0.5]n (1; dpa = diphenate and pyz = pyrazine) and [Mn3(bpdc)3(py)4]n (2; bpdc = biphenyl-4,4'-dicarboxylate and py = pyridine) were successfully isolated by the hydro- and solvo-thermal technique, respectively. The complexes were characterized by elemental and thermal analysis, vibrational IR spectroscopy, and by single crystal x-ray structure determination. For 2, magnetic property was also investigated. Complex 1 is a two-dimensional layer structure consisting of a paddle-wheel building unit of Zn-dpa chains bridged by pyrazine. While, complex 2 consists of linear trimeric Mn3 cluster as building unit to form 3D network. In the complexes, dpa2− (1) and bpdc2−(2) ligands show a typical bis-monodendate bridging and two kinds of bridging modes; a typical bridging and chelating/bridging mode, respectively.

Solution-Derived Hafnium Lanthanum Oxide Films Prepared Using Ion-Beam Irradiation and Their Applications as Alignment Layers for Twisted-Nematic Liquid Crystal Displays

  • Oh, Byeong-Yun
    • Transactions on Electrical and Electronic Materials
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    • 제17권6호
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    • pp.355-358
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    • 2016
  • We present the alignment characteristics of LC (liquid crystal) molecules on solution-derived HLO (hafnium lanthanum oxide) films fabricated using IB (ion-beam) irradiation. We then demonstrated that LC molecules can be homogeneously and uniformly aligned on the HLO film irradiated at an IB incident energy of 1.2 keV. Physicochemical analysis methods such as atomic force microscopy and X-ray photoelectron spectroscopy were used to verify the LC alignment mechanism on the IB-irradiated HLO film. In addition, the electro-optical performance of a TN (twisted-nematic) cell fabricated using the IB-irradiated HLO film exhibited characteristics superior to those of the conventional TN cell fabricated using a rubbed polyimide layer.

Carbamide Peroxide 용액(溶液)의 안정성(安定性) (A Study on the Stability of Carbamide Peroxide Solution)

  • 이계주;유병설
    • 약학회지
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    • 제28권6호
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    • pp.299-303
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    • 1984
  • In order to eluciate the effect of humidity and organic solvent on the decomposition of carbamide peroxide, the kinetic study was carried out. The carbamide peroxide was prepared from urea and 30%-hydrogen peroxide. The accelerated stability analysis for carbamide peroxide crystal in various relative humidity, and for 10%-carbamide peroxide solution of organic solvents were investigated. Both humidity and temperature were important factors influencing the decomposition rate of carbamide peroxide crystal. The higher the humidity and temperature, the greater was the reaction rate. The breakdown rate of crystal was observed as an apparent zero-order, and was faster than the rate of decomposition in dilute propylene glycol, glycerine or sorbitol solutioos which were measured as an apparent first-order reaction. The more dilute to 10% the organic solvents of 10%-carbamide peroxide, the slower was breakdown rate. It is, therefore, useful in the aspects of stability and economics to substitute solvent of carbamide peroxide topical solution (USP XXI) with 10%-propylene glycol or glycerine instead of anhydrous glycerine.

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포토닉 밴드갭 광결정의 제작과 선형 및 비선형 광학 특성 연구 (Fabrication and Linear & Nonlinear Optical Characterization of Photonic Crystals)

  • Ha Na Yeong;U Yeon Gyeong;Hwang Ji-Su;Jang Hye-Jeong;Park Byeong-Ju;U Jeong-Won
    • 한국광학회:학술대회논문집
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    • 한국광학회 2002년도 하계학술발표회
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    • pp.162-163
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    • 2002
  • 1-D photonic band-gap structure is identified in a cholesteric liquid crystal system. The optical transmission spectrum is measured and compared with the theoretical analysis. Nonlinear transmission is measured near the band edge. Also 3-D photonic band-gap structures are fabricated from dielectric colloidal polystyrene beads through a centrifuge method. The fabricated photonic crystals exhibit opalescent colors under white light and show a clear diffraction peak dependent on the incident angle of the light beam. Also the scanning electron microscope image was taken to verify the face-centered cubic crystal structure. Bragg's law and Snell's law are employed to describe the position of angle resolved diffraction peaks. It was shown that the optically deduced effective refractive index and lattice constants were in good agreement with the crystal structure identified by scanning electron microscope.

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단결정 초내열합금에서 응고속도에 따른 응고 및 공정조직의 형성 거동 (Formation of Solidification and Eutectic Microstructures with Solidification Rates in the Single Crystal Superalloy CMSX 10)

  • 이재현
    • 한국재료학회지
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    • 제18권11호
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    • pp.577-582
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    • 2008
  • Directional solidification experiments were carried out at $1-300\;{\mu}m/sec$ solidification rates in the single crystal superalloy, CMSX 10. The solid/liquid interface morphology changed from planar to dendritic, and the dendrite spacing became finer as the solidification rate increased. The pool size of the ${\gamma}/{\gamma}'$ eutectic, formed between dendrites, reduced as the solidification rate increased. The phase formation temperatures, such as the solidus, liquidus and eutectic, were estimated by differential scanning calorimetry (DSC) analysis. The morphology of the ${\gamma}/{\gamma}'$ phase, known to be eutectic, showed ${\gamma}'$ cells with a $\gamma$ intercellular network, and this ${\gamma}/{\gamma}'$ was composed of coarse and fine ${\gamma}/{\gamma}'$ regions. In this study, it is suggested that the ${\gamma}/{\gamma}'$ phase was a coupled peritectic.The solidification procedure of the ${\gamma}/{\gamma}'$ between dendrites is also discussed.

수정진동자 미세저울을 이용한 방식도막의 물 흡수 측정 (Measurement of Water Absorption in Anticorrosive Organic Coatings Using Quartz Crystal Microbalance (QCM))

  • 이근대;도윤정;김진호;박성수;홍성수;서차수;박진환
    • 한국해양공학회지
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    • 제17권6호
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    • pp.77-82
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    • 2003
  • The absorption of water into an anti-corrosive organic coating, such as alkyd and urethane resin coating, was investigated, using a quartz crystal microbalance (QCM). Anticorrosive properties of the coatings were also measured, by means of electrochemical impedance spectroscopy (EIS). The overall absorption of water in the coating is determined by the chemical nature of resin, and decreases with increasing thickness. The enhancement of anti-corrosive performance, through increase of coating thickness, was more remarkable in the case of the coating that hadlower equilibrium water absorption. The absorption kinetics curves were Fickian in nature. The EIS analysis confirmed that the resin, having lower equilibrium water absorption, shows higher anti-corrosive performan.

Electric Property Analysis of SiC Semiconductor Wafer for Power Device Application

  • 김정곤;안준호;서정두;김정규;견명옥;이원재;김일수;신병철;구갑렬
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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    • pp.207-207
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    • 2006
  • We investigated the effects of hydrogen addition to the growth process of SiC single crystal using sublimation physical vapor transport(PVT) techniques. Hydrogen was periodically added to an inert gas for the growth ambient during the SiC bulk growth Grown 2"-SiC single crystals were proven to be the polytype of 6H-SiC and carrier concentration levels of about $10^{17}/cm^3$ was determined from Hall measurements. As compared to the characteristics of SiC crystal grown without using hydrogen addition, the SiC crystal without definitely exhibited lower carrier concentration and lower microplpe density as well as reduced growth rate.

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