• Title/Summary/Keyword: TEM.

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TEM Sample Preparation of Heterogeneous Materials by Tripod Polishing and Their Microstructures (Tripod Polishing을 이용한 불균질 재료의 TEM 시편준비 방법과 미세조직 관찰)

  • Kim, Yeon-Wook;Cho, Myung-Ju
    • Applied Microscopy
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    • v.34 no.2
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    • pp.95-102
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    • 2004
  • The TEM samples prepared by ion milling have the advantage that thin area can be obtained from almost any materials. However, it has the disadvantage that the amount of thin area can often be quite limited. For the cross-sectioned samples and grossly heterogeneous materials, the thickness of less than $0.1{\mu}m$ can be achieved by mechanical grinding and polishing (tripod polisher) and then the TEM samples may be ion-milled for final thinning or cleaning. These approaches were described in this paper. Examples of TEM observations were taken from cross-section samples of thin films on silicon and sapphire, from diffusion layers between $Mo_5Si_3\;and\;Mo_2B$, and from rapidly solidified 304 stainless steel powders embedded in electroplated copper.

The Analysis of the Effects of Design Parameters on the Energy Efficiency and Performance of TEM Dehumidifiers (열전모듈 제습기의 에너지 효율과 성능에 미치는 설계 인자의 영향 분석)

  • Lee, Tae-Hee
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.16 no.3
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    • pp.1-7
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    • 2020
  • To provide a design direction for high efficiency thermoelectric module(TEM) dehumidifiers, the effects of design factors of TEM dehumidifiers on dehumidification energy efficiency and performance were numerically investigated. The design factors considered in this study are the TEM capacity, the performance of heat exchangers on the heating and cooling surfaces of the TEM. The higher capacity of the TEM results the higher dehumidification energy efficiency and performance at some operating voltage. The enhanced performance of the heat exchanger on heating surface increased the dehumidification energy efficiency and performance at all the operating voltage. The enhanced performance of the heat exchanger on cooling surface decreased the dehumidification energy efficiency and performance at all operating voltage.

Study of statistical distribution for four-port TEM cell

  • Jeon, Sangbong;Kwon, Jong-Hwa
    • Journal of Multimedia Information System
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    • v.1 no.2
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    • pp.127-132
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    • 2014
  • The transverse electromagnetic (TEM) cells are widely used for electromagnetic compatibility (EMC) testing and field probe calibrations. We propose the verification of TEM mode with statistical method using a four-port TEM cell. The verification results are compared with Normal, Rayleigh, and Gamma distribution. As a result, the 75 % quantile of the Rayleigh distribution is excellent agreement with the true quantiles for a number of calibration points.

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Mapping of Underground Geological Boundaries overlain by Conductive Overburden: Application of TEM Soundings (TEM 탐사에 의한 간척지내 전도성 표층 하부 지질 구성 파악)

  • Hwang, Hak-Soo;Moon, Sang-Ho
    • The Journal of Engineering Geology
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    • v.21 no.3
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    • pp.213-219
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    • 2011
  • Transient/time-domain electromagnetic (TEM) soundings were carried out on reclaimed land, since the TEM sounding has good resolution of a conductive and thin overburden. The reclamation material is marine clay dredged from the seafloor, which is currently undergoing consolidation in the upper part of the dredged layer. The conductivity of the marine-origin clay is generally more than 0.3 S/m. The aim of the TEM sounding was to determine the depths of weathered and soft rocks overlain by thick and conductive overburden. The TEM responses were measured at delay times of 0.050-20.575 ms with a $30{\times}30$ m coincident loop array. Data from the TEM inversion and core logging indicate that the resistivities of the conductive overburden are less than 2 ${\Omega}$-m, while those of the weathered and soft rocks are 10-20 and 70 ${\Omega}$-m, respectively. The depth to weathered rock is 26-58 m and the depth to soft rock is 46-75 m.

Observation and Analysis of Dislocation Spacing in the Subgrain boundary on IN 617 (IN 617의 아결정립계의 전위간격 분석법에 관한 고찰)

  • An, Seong-Uk;Lee, Jong-Min
    • Korean Journal of Materials Research
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    • v.5 no.2
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    • pp.184-190
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    • 1995
  • IN 617 was crept under stresses of 107 and 180 MPa with monotonic deformation to strains of $\varepsilon$= 0.03 - 0.30 at 1073K. In order to determine the distances between the subgrain boundaries, the deformed specimens were examined at magnifications of one hundred thousand times by TEM. In cases . where TEM observations were not possible, subgrain angles($\theta$_{s}=sin^{-1}$(b/s))were measured by Kikuchi diffraction lines. The $\theta$_{k}$ converted from s values measured directly by TEM agreed very well with those measured from Kikuchi lines. Therefore, it was found that the $\theta$_{k}$ values could be used in obtaining s, especially in cases where it is impossible to measure s by TEM.

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TEM specimen preparation for observation of Cu oxides precipitated in the polyimide film and characterization of Cu oxide particles (폴리이미드박막내에 석출된 구리산화물 관찰을 위한 TEM 시편 제조와 구리산화물 분석)

  • You, Young-Sek;Kim, Young-Ho
    • Applied Microscopy
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    • v.25 no.1
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    • pp.130-138
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    • 1995
  • TEM specimen preparation methods have been examined to characterize Cu oxide particles in the polyimide film. Polyimide films were prepared by coating polyamic acid onto Cu films which had been deposited on TEM-mask and glass substrates and Cu foil, followed by thermal curing. In case of TEM-mask, direct observation was possible without further preparation. In other cases, TEM specimen were made by separating polyimide film from the substrate. Polyimide films were removed from glass and Cu foil by dissolving glass in HF solution and Cu foil in $H_{2}SO_{4}$ solution. TEM-mask observation confirms that fine $Cu_{2}O$ particles precipitate in the polyimide as a result of reaction of polyamic acid with Cu. However $Cu_{2}O$ particle reacts with HF and $H_{2}SO_{4}$ solution during dissolving the substrate and interpretation could be misled. It is concluded characterization of $Cu_{2}O$ particle in polyimide using TEM-mask is better than other methods.

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Extended-Spectrum $\beta$-Lactamase (ESBL) Typing of Klebsiella pneumoniae Isolated from Clinical Specimen in Pusan (부산시내 종합병원의 임상 검체에서 분리된 Extended -Spectrum $\beta$-Lactamase 생성 Klebsiella pneumoniae의 형별 분류)

  • 김윤태;이훈구
    • Korean Journal of Microbiology
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    • v.36 no.3
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    • pp.221-227
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    • 2000
  • This study was performed to investigate the biological characteristics of twenty isolates of extended spectnlm $\beta$-lactamase (ESBL) producing Klebsiellapnezm~onia collected kom the various clinical specimens of three hospitals in Pusan. Isoelectric focusing (IEF) and PCR were used to determine the types of $\beta$-lactamase gene in this study. Twenty isolates of ESBL producing Klebsiellnp~ieun~or~iae could be divided by PCR, such as TEM type (I1 strains), SHV type (8 strains); non TEM non SHV type (1 strain). In the isoelechic focusing test, the PI of TEM type was 5.2-6.0 and that of SHV type was 6.9-7.4. According to the pI value and PCR bands, twenty strains of ESBL Klebsiellapneumoniae were divided into 5 types: TEM type @I 5.2-6.0; 1080 bp on PCR band), TEM + SHV type (pI 5.2-6.0; andpI 7.0-7.4; 1080 bp and 599 bp on PCR band), SHV type (pl7.0-7.4; 599 bp on PCR band), non TEM non SHV type, and otber type (PCR result was SHV type but pI was not detected).

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Study on Surface Damage of Specimen for Transmission Electron Microscopy(TEM) Using Focused Ion Beam(FIB) (집속 이온빔을 이용한 투과 전자 현미경 시편의 표면 영향에 관한 연구)

  • Kim, Dong-Sik
    • 전자공학회논문지 IE
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    • v.47 no.2
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    • pp.8-12
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    • 2010
  • TEM is a powerful tool for semiconductor material analyses in structure or biological sample in micro structure. TEM observation need to make to coincide specimens for special purpose. in this paper, we have experimented for minimum surface damage on bulk wafer and patterned specimen by various conditions such as accelerating energy, depth of ion beam, ion milling types, and etc. in various specimen preparation methods by FIB (Focus Ion Beam). The optimal qualified specimens are contain low mounts of surface damage(about 5 nm) on patterned specimen.

Optimization of TEM Sample Preparation for the Microstructural Analysis of Nitride Semiconductors (질화물 반도체의 미세구조 분석을 위한 최적의 TEM 시편 준비법)

  • Cho, Hyung-Koun;Kim, Dong-Chan
    • Korean Journal of Materials Research
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    • v.13 no.9
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    • pp.598-605
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    • 2003
  • The optimized conditions for the cross-sectional TEM sample preparation using tripod polisher and ion-beam miller was confirmed by AFM and TEM. For the TEM observation of interfaces including InGaN layers like InGaN/GaN MQW structures, the sample preparation by the only tripod polishing was useful due to the reduction of artifacts. On the other hand, in case of the thick nitride films like ELO, PE, and superlattice, both tripod polishing and controlled ion-beam milling were required to improve the reproducibility. As a result, the ion-beam milling with the $60^{\circ}$modulation showed the minimum height difference between film and sapphire interface and the ion-beam milling of the $80^{\circ}$modulation showed the broad observable width.

Cross-sectional TEM Specimens Priparation of Precisely Selected Regions of Semiconductor Devices using Focused Ion Beam Milling

  • Kim, Jeong-Tae;Kim, Ho-Jeong;Jo, Yun-Seong;Choe, Su-Han
    • Korean Journal of Materials Research
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    • v.3 no.2
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    • pp.193-196
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    • 1993
  • A procedure for preparing cross-sectional specimens for transmission electron microscopy(TEM)by focused ion beam(FIB)milling of specific regions of semiconductor devices is outlined. This technique enables TEM specimens to be pripared at precisely preselected area. In-situ #W thin film deposition on the top surface of desired site is complementally used to secure the TEM specimens to be less wedge shaped, which is main shortcoming of previous FIB-assisted TEM sample preparation technique. This technique is quite useful for the TEM sample priparation for fault finding and the characterization of fabrication process associated with submicron contact technologies.

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