• 제목/요약/키워드: Physical characterization

검색결과 637건 처리시간 0.036초

Hot stage microscopy and its applications in pharmaceutical characterization

  • Arun Kumar;Pritam Singh;Arun Nanda
    • Applied Microscopy
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    • 제50권
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    • pp.12.1-12.11
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    • 2020
  • Hot stage microscopy (HSM) is a thermal analysis technique that combines the best properties of thermal analysis and microscopy. HSM is rapidly gaining interest in pharmaceuticals as well as in other fields as a regular characterization technique. In pharmaceuticals HSM is used to support differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA) observations and to detect small changes in the sample that may be missed by DSC and TGA during a thermal experiment. Study of various physical and chemical properties such sample morphology, crystalline nature, polymorphism, desolvation, miscibility, melting, solid state transitions and incompatibility between various pharmaceutical compounds can be carried out using HSM. HSM is also widely used to screen cocrystals, excipients and polymers for solid dispersions. With the advancements in research methodologies, it is now possible to use HSM in conjunction with other characterization techniques such as Fourier transform infrared spectroscopy (FTIR), DSC, Raman spectroscopy, scanning electron microscopy (SEM) which may have additional benefits over traditional characterization techniques for rapid and comprehensive solid state characterization.

Molecular Characterization and Mitogenic Activity of a Lectin from Purse Crab Philyra Pisum

  • Na, Jong-Cheon;Park, Byung-Tae;Chung, Woo-Hyuk;Kim, Ha-Hyung
    • The Korean Journal of Physiology and Pharmacology
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    • 제15권4호
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    • pp.241-244
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    • 2011
  • A lectin from the hemolymph of purse crab, Philyra pisum, was found to have anti-proliferative activity on human lung cancer cells by our laboratory. In this study, P. pisum lectin (PPL) was molecularly characterized including molecular mass, amino acid sequences, amino acid composition, and the effects of metal ions, temperature, and pH on the activity. We found that PPL showed mitogenic activity on human lymphocytes and BALB/c mouse splenocytes. The mitogenic activity (maximum stimulation index, $SI=9.57{\pm}0.59$) of PPL on human lymphocytes was higher than that of a standard well-known plant mitogen, concanavalin A (maximum $SI=8.80{\pm}0.59$). The mitogenic activity mediated by PPL is required for optimum dosing, and higher or lower concentrations caused decreases in mitogenic response. PPL also induced mitogenic activity on mouse splenocytes, however, the maximum SI ($1.77{\pm}0.09$) on mouse splenocytes of PPL was lower than that ($2.14{\pm}0.15$) of concanavalin A. In conclusion, PPL is a metal ion-dependent monomer lectin with mitogenic activity, and could be used as a lymphocyte or splenocyte stimulator.

화법에 의한 성격표현에 활용할 소리대본 작성법 (Use of Voice Script For Speech Characterization)

  • 이기호
    • 한국콘텐츠학회논문지
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    • 제11권12호
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    • pp.976-985
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    • 2011
  • 본 연구는 배우가 극중 인물의 성격을 창조하는 한 과정으로서, 언어적 성격창조를 위해 화법에 의한 성격표현에 활용할 소리대본의 작성 및 그 활용에 관한 연구이다. 배우의 연기에 있어서 궁극적인 목표는 극중 인물의 성격을 창조하여 완벽하게 구현해내는 것이라고 할 수 있으며, 그 목표를 달성하기 위하여 배우는 성격분석 방법을 터득하는 한편, 다양한 연기훈련으로 연기술을 연마하여 자신의 연기역량을 향상 시키는데 주력한다. 배우의 연기역량은 신체적 표현능력과 언어적 표현능력 개발로 향상된다. 따라서 배우들은 극중 인물의 성격을 창조하여 표현해내기 위하여 신체적, 언어적 표현능력을 향상시키는데 많은 노력을 기울인다. 그 중에서도 언어적 성격창조는 호흡과 발성, 그리고 화법에 의한 대사의 구사로 창조된다. 본고에서는 자유로운 호흡과 발성의 토대위에서 배우의 발성역량을 향상시키고, 향상된 발성역량으로 다양한 화법을 구사할 수 있는 방법을 연구, 제시함으로써 배우들이 언어적 성격창조를 효과적으로 할 수 있는 방법을 도출하고자 하였다. 극중 인물의 언어적 성격창조를 위해 다양한 화법, 즉 말하는 방법과 양식을 터득하게 함으로써 배우는 극중 인물의 성격을 효과적으로 창조할 수가 있게 된다. 따라서 효과적인 언어적 성격창조의 한 방법으로 화법에 의한 성격표현술을 습득하는 데 효과적인 방법론으로서의 소리대본을 작성하는 방법을 제시하고 활용토록 하고자 한다.

Binding Specificity of Philyra pisum Lectin to Pathogen-Associated Molecular Patterns, and Its Secondary Structure

  • Park, Byung Tae;Kim, Byung Sun;Park, Heajin;Jeong, Jaehoon;Hyun, Hanbit;Hwang, Hye Seong;Kim, Ha Hyung
    • The Korean Journal of Physiology and Pharmacology
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    • 제17권6호
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    • pp.547-551
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    • 2013
  • We recently reported a Philyra pisum lectin (PPL) that exerts mitogenic effects on human lymphocytes, and its molecular characterization. The present study provides a more detailed characterization of PPL based on the results from a monosaccharide analysis indicating that PPL is a glycoprotein, and circular dichroism spectra revealing its estimated ${\alpha}$-helix, ${\beta}$-sheet, ${\beta}$-turn, and random coil contents to be 14.0%, 39.6%, 15.8%, and 30.6%, respectively. These contents are quite similar to those of deglycosylated PPL, indicating that glycans do not affect its intact structure. The binding properties to different pathogen-associated molecular patterns were investigated with hemagglutination inhibition assays using lipoteichoic acid from Gram-positive bacteria, lipopolysaccharide from Gram-negative bacteria, and both mannan and ${\beta}$-1,3-glucan from fungi. PPL binds to lipoteichoic acids and mannan, but not to lipopolysaccharides or ${\beta}$-1,3-glucan. PPL exerted no significant antiproliferative effects against human breast or bladder cancer cells. These results indicate that PPL is a glycoprotein with a lipoteichoic acid or mannan-binding specificity and which contains low and high proportions of ${\alpha}$-helix and ${\beta}$-structures, respectively. These properties are inherent to the innate immune system of P. pisum and indicate that PPL could be involved in signal transmission into Gram-positive bacteria or fungi.

A Novel Transmission Line Characterization Based on Measurement Data Reconfirmation

  • 어영선
    • 한국전자파학회지:전자파기술
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    • 제27권3호
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    • pp.17-27
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    • 2016
  • In the high-frequency characterizations of planar circuit components, measurement data may not be physical. It is mainly due to resonance effects concerned with discontinuities which are inevitable for a planar component characterization. In this paper, a novel accurate transmission line characterization method is presented that excludes the resonance effects based on measurement data reconfirmation. For the physically obvious data acquisition near the resonance frequencies of a transmission line, the additional lines with different line lengths are fabricated on the same substrate. The test transmission lines are characterized by using vector network analyzer (VNA) in 100 MHz to 26.5 GHz. It is shown that an accurate transmission line characterization can be achieved with the proposed measurement data reconfirmation technique.

Microstructure Characterization of $SiC_p$-reinforced Aluminum Matrix Composites by Newly Developed Computer-based Algorithms

  • Kretz, Ferenc;Gacsi, Zoltan;Gur, C. Hakan
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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    • pp.1061-1062
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    • 2006
  • This paper presents a new approach for analyzing the microstructure of $SiC_p$-reinforced aluminum matrix composites from digital images. Various samples of aluminum matrix composite were fabricated by hot pressing the powder mixtures with certain volume and size combinations of pure Al and SiC particles. Microstructures of the samples were analyzed by computer-based image processing methods. Since the conventional methods are not suitable for separating phases of such complex microstructures, some new algorithms have been developed for the improved recognition and characterization of the particles in the metal matrix composites.

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유기 분자선 증착법에 의해 성막된 Pentacene 박막의 물리적, 전기적 특성에 관한 연구 (Physical and electrical characteristics of Pentacene thin films prepared by)

  • 김대엽;김대식;최종선;강도열;김영관
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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    • pp.605-608
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    • 1999
  • We report investigations on a Pentacene thin film as a component for active layer of Organic thin film transistors. Pentacene film was deposited by Organic Molecular Beam Deposition(OMBD) and Al electrode was deposoted by vacuum evaporation. Electrical characterization of Pentacene films were measured by the three-terminal contact resistance methods, as the results contact resistance between pentacene films and the Aluminium electrode is 5.064G$\Omega$. The Al contact with the pentacene shows the bottom contact resistance. From the current-voltage characteristics, electrical conductivity of the Pentacene film is found as ~ 10$^{-4}$ /cm. physical characterization of pentacene films were measured by UV-spectrum and Cyclic-Voltammetry method.

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Rough surface characterization using off-axis digital holographic microscopy compensated with self-hologram rotation

  • Ibrahim, Dahi Ghareab Abdelsalam
    • Current Applied Physics
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    • 제18권11호
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    • pp.1261-1267
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    • 2018
  • In this paper, an off-axis digital holographic microscopy compensated with self-hologram rotation is presented. The process is implemented via subtracting the unwrapped phase maps of the off-axis parabolic hologram and its rotation $180^{\circ}$ to eliminate the tilt induced by the angle between the spherical object wave O and the plane reference wave R. Merit of the proposed method is that it can be done without prior knowledge of physical parameters and hence can reconstruct a parabolic hologram of $1024{\times}768$ pixels within tens of milliseconds since it doesn't require a digital reference wave. The method is applied to characterize rough gold bumps and the obtained results were compared with those extracted from the conventional reconstruction method. The comparison showed that the proposed method can characterize rough surfaces with excellent contrast and in realtime. Merit of the proposed method is that it can be used for monitoring smaller biological cells and micro-fluidic devices.

Nano-characterizations of low-dimensional nanostructural materials

  • Hye-Won Seo;Jae-Ung Lee;Chan-Ho Yang;Kanghyun Chu
    • Journal of the Korean Physical Society
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    • 제80권
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    • pp.1035-1041
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    • 2022
  • Nondestructive nano-characterization methods were reviewed with respect to technical aspect and practicability. Micro-photoluminescence, cathodoluminscence and Raman spectroscopy with mapping modes were investigated as optical characterization tools, while electron backscatter diffraction and piezoresponse force microscopy were introduced as monitoring techniques for the crystallographic and electromechanical properties. Especially, the spatial resolution of the data acquisition and analysis was carefully inspected in the representative semiconducting nanomaterial systems. Some of efforts to overcome the limit of these characterizations were also taken into consideration.