• Title/Summary/Keyword: 버팅

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An Ultrastructural Study of Sertoli Cells in Human Fetal Testes (태아 고환에서 버팀세포의 미세형태학적 연구)

  • Lee, Tae-Jin;Yoon, Sam-Hyun;Kim, Mi-Kyung;Park, Eon-Sub;Yoo, Jae-Hyung
    • Applied Microscopy
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    • v.31 no.2
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    • pp.157-165
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    • 2001
  • Sertoli cells in the normal adult testis are nondividing cells, which are relatively inconspicuous on cross section of the seminiferous tubule and comprise about 10% to 15% of the tubular cellular elements. Ultrastructurally, Sertoli cells have characteristic nucleoli, plasma membrane, and cytoplasmic components. The plasma membrane has two types of intercellular junctions which are developed at puberty: junctions between adjacent Sertoli cells and Sertoli cell-germ ceil junction. However, the ultrastructural findings of Sertoli cells in human fetus is not fully elucidate yet. In the present study, human fetal testes ($14\sim27$ weeks) obtained from artificially induced abortions legally without gross malformation were studied using transmission electron microscopy to make clear the differentiation process of Sertoli cells in human. In human fetal testes from 14 weeks to 27 weeks, the cell junctions of Sertoli-germ cells and Sertoli-Sertoli cells are desmosome like structure and not tight junction or desmosome. The Overall intracytoplasmic organelles of Sertoli cells are relatively sparse. The mitochondrias are relatively abundant but no developed cristae. And the rough endoplasmic reticuli are abundant and smooth endoplasmic reticuli are sparse. The amount of lipid droplets are regularly observed in human fetal Sertoli cells. No microfilaments or Charcot-Bottcher's crystalloids are present. From the results, Sertoli cells in human fetal testes are somewhat different ultrastructural findings with puberty or adult. However, to make clear the differentiation process of Sertoli cells in human, further study for 28 weeks to puberty is required.

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A Study on Characteristics of column fails in DDI DRAM (DDI DRAM에서의 Column 불량 특성에 관한 연구)

  • Chang, Sung-Keun;Kim, Youn-Jang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.6
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    • pp.1581-1584
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    • 2008
  • In dual-polycide-gate structure with butting contact, net doping concentration of polysilicon was decreased due to overlap between $n^+$ and $p^+$ and lateral dopant diffusion in silicide/polysilicon layers. The generation of parasitic Schottky diode in butting contact region is attributed both to the $CoSi_2$-loss due to $CoSi_2$ agglomeration and to the decrease in net doping concentration of polysilicon layer. Parasitic Schottky diode reduces noise margin of sense amplifier in DDI DRAM, which causes column fail. The column fail could be reduced by physical isolation of $n^+/p^+$ polysilicon junction or suppressing $CoSi_2$ agglomeration by using nitrogen implantation into $p^+$ polysilicon before $CoSi_2$ formation.

Identification of Abnormal Compressor using Wavelet Transform (Wavelet 변환에 의한 압축기의 이상상태 식별)

  • 정지홍;이기용;김정석;이감규
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.361-364
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    • 1995
  • Wavelet Transform is a new tools for signal processing, such as data compressing extraction of parameter for Reconition and Diagnostics. This transform has an advandage of a good resolution compared to Fast Fourier Transform (FFT) In this study, we employ the wavelet transform for analysis of Acoustic Emission raw signal generated form rotary compressor. In abnormal condition of rotary compressor, the state of operating condition can be classified by analizing coefficient of wavelet transformed signal.

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Abnormal condition analysis of compressor using AE raw signal (AE 원신호를 이용한 압축기의 이상상태 분석)

  • 김전하;이기용;김정석;이감규
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.365-368
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    • 1995
  • Rotary Compressor has many AE(Acoustic Emission) sources according to condition of parts because it is operated with combination of various parts. In this study, analysis of AE raw signal generated form Rotary compressor which artificially-made parts inflicted abnormal condition was carried out. AE raw signals were acquired form high-speed A/D board, and many burst type signals were observed. By analyzing burst type signals which is caused form internal AE source,efficient AE parameters for monitoring and diagnosis were presented.

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Analysis of effect of parasitic schottky diode on sense amplifier in DDI DRAM (DDI DRAM의 감지 증폭기에서 기생 쇼트키 다이오드 영향 분석)

  • Chang, Sung-Keun;Kim, Youn-Jang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.2
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    • pp.485-490
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    • 2010
  • We propose the equivalent circuit model including all parasitic components in input gate of sense amplifier of DDI DRAM with butting contact structure. We analysed the effect of parasitic schottky diode by using the proposed model in the operation of sense amplifier. The cause of single side fail and the temperature dependence of fail rate in DDI DRAM are due to creation of the parasitic schottky diode in input gate of sense amplifier. The parasitic schottky diode cause the voltage drop in input gate, and result in decreasing noise margin of sense amplifier. therefore single side fail rate increase.