• Title/Summary/Keyword: TEM Journal

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Effect of PZN addition on microstructure of PZT thick films by aerosol deposition process (에어로졸 증착법에 의한 PZT 후막의 미세구조에 미치는 PZN 첨가의 영향)

  • Jang, Joo-Hee;Park, Yoon-Soo;Park, Dong-Soo;Park, Chan
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.28 no.1
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    • pp.14-20
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    • 2018
  • Lead zinc niobate (PZN) added lead zirconate titanate (PZT) thick films with thickness of $5{\sim}10{\mu}m$ were fabricated on silicon and sapphire substrates using aerosol deposition method. The contents of PZN were varied from 0 %, 20 % and 40 %. The initial particles (PZT, 2PZN-8PZT, 4PZN-6PZT) had irregular shape and submicron sizes. The as-deposited film had fairly dense microstructure without any crack, and showed only a perovskite single phase formed with nano-sized grains. The as-deposited films on silicon were annealed at the temperatures of $700^{\circ}C$, and the films deposited on sapphire were annealed at $900^{\circ}C$ in the electrical furnace. The effects of PZN addition on the microstructural evolution were observed using by FE-SEM and HR-TEM.

Toxicity of Talc Containing Tremolite asbestos on Respiratory System in Sprague-Dawely Rats (랫드의 기도로 투여된 투각섬석함유활석이 호흡기계에 미치는 영향 연구)

  • Chung, Yong-Hyun;Han, Jeong-Hee;Kang, Min-Gu;Lee, Sung-Bae;Kim, Jong-Kyu;Kim, Hyeon-Yeong;Yang, Jung-Sun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.20 no.2
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    • pp.119-130
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    • 2010
  • Pulmonary toxicity of talc containing tremolite asbestos (TCT) has been studied in term sequential in Sprague-Dawely rats. UICC chrysotile(average diameter 0.03${\mu}m$, average length 2.93${\mu}m$) was applied as the positive control. TCT was analyzed for its physicochemical properties by transmission electron microscope equipped with energy dispersive X-ray spectrometer(TEM-EDS). The effects of 2mg TCT(talc average diameter 9.7${\pm}$8.4${\mu}m$; tremolite average diameter 1.6${\pm}$1.6${\mu}m$, average length 10.8${\pm}$7.0${\mu}m$) on pathological changes were evaluated after 1, 8 weeks instilled into rat lungs. 2mg Chrysotile continuously affected lung pathological changes. Inflammation and granuloma response broke out from 1 week after instilled with chrysotile and the pathological examination further showed increased legions of lung after 8 weeks. But TCT did not showed lung pathological changes. The biopersistence of TCT and chrysotile was evaluated by TEM- EDS. Whereas chrysotile continuously have retained to 8 weeks instilled into rat lungs, talc of TCT showed statistically significant decrease of diameter from 1 weeks and statistically significant change in Si atomic % compositions at 8 weeks instilled into rat lungs. Physicochemical properties of tremolite of TCT were not affected until 8 weeks instilled into rat lungs. This study showed that the durability of TCT in the lungs is much weaker than chrysotile.

Transepidermal Water Loss, Stratum Corneum Hydration and Transmission Electron Microscope Observation on Acetone Damaged Canine Skin Barrier Model (아세톤에 의해 손상된 개 피부장벽 모델에서의 경표피수분소실도 및 각질층보습도 평가와 전자현미경적 관찰)

  • Oh, Won-Seok;Park, Seong-Jun;Oh, Tae-Ho
    • Journal of Veterinary Clinics
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    • v.27 no.2
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    • pp.142-146
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    • 2010
  • The purpose of this study is to establish experimental canine skin barrier disruption model in dog. The study was designed to investigate the predictive properties of acetone damage using as effect parameters transepidermal water loss (TEWL) and stratum corneum (SC) hydration. To compare the structures of SC intercellular lipids in normal and acetone damaged skin, TEM observations were performed. Six clinically normal, male Beagles without dermatological problems were chosen for this study. Acetone damage was performed at 48hrs after clipping. Efficacy measurements for TEWL and skin hydration were performed before ($t_1$) and after ($t_2$) damage in a temperature- and humidity-controlled room ($2{0\sim}22^{\circ}C$, 50-60%). TEWL and SC hydration values were decreased in the acetone damaged model compared with non damaged skin. In TEM observation of acetone damaged sample, the intercellular lipid lamellae exhibit abnormal and incomplete structure compared with those of normal skin. It seems that acetone damage would be one of canine skin epidermal barrier disruption model for the study of canine atopic dermatitis (AD) as well as dry skin in veterinary dermatology research.

A study of newly recorded genus and species for aerial cyanobacteria Wilmottia murrayi(Oscillatoriales, Cyanobacteria) in Korea (기중성 남세균, Wilmottia murrayi (Oscillatoriales, Cyanobacteria)의 국내 미기록속 및 미기록종에 대한 연구)

  • Lee, Nam-Ju;Seo, Yoseph;Ki, Jang-Seu;Lee, Ok-Min
    • Korean Journal of Environmental Biology
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    • v.37 no.3
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    • pp.260-267
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    • 2019
  • Two aerophytic cyanobacteria from the rockwall of Haje port located in Geum river, Korea, were isolated in unialgal cultures and submitted to polyphasic evaluation. The filaments of the populations presented solitary or several to many parallel arranged. The straight trichomes were not attenuated with rounded apical cell. Phylogenetic analyses based on 16S rDNA sequences indicated that these populations formed the same clade with Wilmottia murrayi and had 99% or greater DNA similarity. Through the ultrastructure of the TEM, these populations showed parietal thylakoid arrangement, which coincides with family Coleofasciculaceae. From the above results, we reported the newly recorded genus Wilmottia, and species W. murrayi in Korea.

Green Synthesis of Silver Nanoparticles Using Cell Extracts of Anabaena doliolum and Screening of Its Antibacterial and Antitumor Activity

  • Singh, Garvita;Babele, Piyoosh K.;Shahi, Shailesh K.;Sinha, Rajeshwar P.;Tyagi, Madhu B.;Kumar, Ashok
    • Journal of Microbiology and Biotechnology
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    • v.24 no.10
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    • pp.1354-1367
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    • 2014
  • In the present work, we describe a simple, cheap, and unexplored method for "green" synthesis of silver nanoparticles using cell extracts of the cyanobacterium Anabaena doliolum. An attempt was also made to test the antimicrobial and antitumor activities of the synthesized nanoparticles. Analytical techniques, namely UV-vis spectroscopy, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and TEM-selected area electron diffraction, were used to elucidate the formation and characterization of silver-cyanobacterial nanoparticles (Ag-CNPs). Results showed that the original color of the cell extract changed from reddish blue to dark brown after addition of silver nitrate solution (1 mM) within 1 h, suggesting the synthesis of Ag-CNPs. That the formation Ag-CNPs indeed occurred was also evident from the spectroscopic analysis of the reaction mixture, wherein a prominent peak at 420 nm was noted. TEM images revealed well-dispersed, spherical Ag-CNPs with a particle size in the range of 10-50 nm. The X-ray diffraction spectrum suggested a crystalline nature of the Ag-CNPs. FTIR analysis indicated the utilization of a hydroxyl (-OH) group in the formation of Ag-CNPs. Ag-CNPs exhibited strong antibacterial activity against three multidrug-resistant bacteria. Additionally, Ag-CNPs strongly affected the survival of Dalton's lymphoma and human carcinoma colo205 cells at a very low concentration. The Ag-CNPs-induced loss of survival of both cell types may be due to the induction of reactive oxygen species generation and DNA fragmentation, resulting in apoptosis. Properties exhibited by the Ag-CNP suggest that it may be used as a potential antibacterial and antitumor agent.

Synthesis and characterization of GaN nanoparticles by pulsed laser deposition (펄스레이저증착법에 의한 GaN 나노입자의 합성 및 특성분석)

  • ;;;Koshizaki Naoto
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.13 no.2
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    • pp.79-82
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    • 2003
  • GaN nanoparticles were synthesized by the pulsed laser deposition (PLD) process on $SiO_2$substrate after irradiating the surface of the GaN sintered pellet by the ArF (193 nm) excimer laser. At this moment Ar gas pressure of 100 Pa, 50 Pa, 10 Pa and 1 Pa were applied during the ablation process and laser power of 100 mJ and 200 mJ were also applied. The synthesized fan nanoparticles were characterized by XRD, SEM, TEM, XPS and optical absorption spectra. The synthesized GaN nanoparticles had the crystallite sizes of 20~30 nm, and besides, GaN nanoparticles synthesized under low Ar gas pressure compared to the others corresponded with stoichiometry, and the optical band edge of the GaN nanoparticles was blueshifted.

Crystalline Growth Behavior of SrAl2O4Synthesized by the Polymerized Complex Method (착체중합법으로 함성한 SrAl2O4의 결정 성장 거동 관찰)

  • Kim, Hyung-Joon;Lee, Hyun-Kwuon;Park, Jeong-Hyun
    • Journal of the Korean Ceramic Society
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    • v.41 no.4
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    • pp.340-343
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    • 2004
  • SrA1$_2$O$_4$was prepared by polymerized complex method and crystalline growth was investigated. Precursors was annealed at temperatures form 900 to 100$0^{\circ}C$, for different time(between 0 and 10 h), and that was determined by Transmittance Electron Microscopy (TEM) and X-Ray Diffractometer (XRD). Crystalline size was calculated by Scherrer's equation and its variation was studied. It increased rapidly in the primary stage and then slowly as a function of square root of time. so, It was grown to 32, 45 and 59nm after heating treatment at 900, 980, and 100$0^{\circ}C$ for 10 h respectively. Cstalline growth rates were 4.5, 9.6, and 18.6 nm/h$^{1}$2/ as a addition of heating temperature.

Melt growth and superconducting properties of Sm-doped YBCO super-conductor by zone melting method (국부용융성장법으로 제조된 Sm이 첨가된 YBCO 초전도체의 용융온도 및 성장 속도에 따른 미세구조)

  • 김소정
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.14 no.2
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    • pp.68-72
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    • 2004
  • Sm-doped YBCO high $T_c$ superconductor was directionally grown by zone melt growth process in air atmosphere. Cylindrical green rods of $(Sm/Y)_{1.8}Ba_{2.4}Cu_{3.4}O_{7-x}$[(Sm/Y)1.8] oxides were fabricated by cold isostatic pressing (CIP) method using rubber mold. Based on the variation of melting temperature and growth rate, the microstructure and superconducting properties were systematically measured by using optical micrographs, TEM and SQUID magnetometer. In this study optimum melting temperature and growth rate were $1085^{\circ}C$ and 3.5 mm/hr respectively. Nonsuperconducting $(Sm/Y)_2BaCuO_5$ inclusions of (Sm/Y)1.8 superconductor were uniformly distributed within the superconducting (Sm/Y) $Ba_2Cu_3O^{7-x}$ matrix. The directionally melt-textured (Sm/Y)1.8 superconductor showed an onset $T_c$ $\geq$ 90K and sharp superconducting transition.

A Design of Multiple Microstrip Line Coupled Circuit for Microwave Integrated Circuit (마이크로파 집적회로를 이용한 복수 마이크로스트립선 결합회로의 설계)

  • Park, Yhl;Kang, Hee-Chang;Chin, Youn-Kang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.16 no.9
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    • pp.862-876
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    • 1991
  • In this theses, the procedure for finding the equivalent immittance of an n-line coupled structures is presented in terms of the normal mode parameters of the n-line coupled system. The above generalized equations can be applied to the various Coupled structures including directional couplers, DC blocks, bandpass/band elimination filters, and various other uniformly coupled filters. The design equations are based on a simplified TEM(Quasi TEM) mode. The obtained results and the definition of the scattering parameters for a general coupled line four port with arbitrary terminations are used to present the procedure to determine the optimum physical dimensions matching the given load impedances connected to input, output port. Multiple coupled rnicrostrip two-port with three lines circuit designed shows little discrepancy between the conventional method and this one. Four port with five lines were fabricated on teflon substrate($e$r=2.55) with its thickness h=l.588mm designed at the center frequency, 4 GHz. Their measured results are fairly close to the ones by computation.

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Effcets of Initial Oxygen Concentration on Oxygen Pileup and the Diffusion of Impurities after High-energy Ion Impaltation (초기 산소 농도가 고에너지 이온 주입시 발생하는 산소 축적 및 불순물 확산에 미치는 영향)

  • 고봉균;곽계달
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.4
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    • pp.48-56
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    • 1999
  • In this paper, we have investigated experimentally the effects of initial oxygen concentration on oxygen pileup phenomenon and the diffusion of implanted impurities. 1.2 MeV $^{11}B^{+}$ and 2.2 MeV $^{31}P^{+}$ ions were implanted into p-type (100) Si wafers with a dose of 1${\times}10^{15}$ / $\textrm{cm}^2$. Secondary ion mass spectrometry(SIMS) measurements were carried out to obtain depth distribution profiles for implanted impurities and oxygen atoms after two-step annealing of $700^{\circ}C$(20 hours)+$1000^{\circ}C$(10 hours). Residual secondary defect distribution and annealing behabiour were also studied by cross-sectional transmission electron microscopy(TEM) observations. Oxygen pileup nearly $R_p$(projected range) were observed by SIMS measurements and considerable amount of residual secondary defect layer were observed by TEM observations. It can be seen that oxygen atoms are trapped at the secondary defects by the experimental results. Enhanced diffusions of boron and phosphorus to the bulk direction were observed with the increasing of initial oxygen concentration.

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