• 제목/요약/키워드: carrier density

검색결과 548건 처리시간 0.02초

DH Laser Diode의 전기적 포화현상에 관한 이론적 해석 (Theoretical Analysis of the Electrical Saturation Behavior of the DH Laser Diode)

  • 박영규;권영기
    • 대한전자공학회논문지
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    • 제15권5호
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    • pp.34-38
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    • 1978
  • rate equation을 사용하여 DH Laser Diode에서 나타나는 전기적 포화현상이 이론적으로 설명되었다. Carrier density는 threshold 이후에 서서히 ns에 접근해가며 이론적으로 계산된 곡선과 예측된 ΔVj는 전에 보고된 실험결과를 정확히 설명한 수 있음이 입증되었다. carrier saturation factor kβ를 제안하였으며 kβ는 L.D의 이상성을 결정하는 중요한 factor 임이 설명되었다. kβ와 β와의 관계를 통해 β가 작으면 작을수록 diode의 특성은 이상적 diode에 가까와짐이 밟혀졌다.

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가스센서용 고순도 다공질 알루미나 담체의 제조 (Preparation of High-purity Porous Alumina Carrier for Gas Sensor)

  • 이창우;현성호;함영민
    • 한국화재소방학회논문지
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    • 제11권3호
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    • pp.15-23
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    • 1997
  • In this study, the alumina for gas sensor was prepared by anodic oxidation. It was stable thermally and chemically, and pore diameter and pore distribution was uniform. And the shape of pore was cylinderical. The aluminum plate was carried out by the thermal oxidation, chemical polishing and electropolishing pretreatment. The pore diameter, pore size distribution, pore density and thickness of alumina was observed with the change of reaction temperature, electrolyte concentration and current density. As a results, It was able to use for carrier because alumina which was prepared by anodic oxidationhas uniform pore size distribution.

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고밀도 칩 신뢰성 개선을 위한 buffered deposition 소자구조에 관한 연구 (A Study on Buffered Deposition Device Structure to Improvement for High Density Chip Realiability)

  • 김환석;이천희
    • 한국시뮬레이션학회논문지
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    • 제17권2호
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    • pp.13-19
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    • 2008
  • 본 연구에서는 드레인 부근의 채널 영역에서 접합 전계를 줄이는 Buffered deposition 구조의 소자를 제안하였다. Buffered deposition 구조의 소자 제작은 첫 번째 게이트를 식각한 후에 NM1(N-type Minor1) 이온주입을 하고 다시 HLD막과 질화막을 덮어 식각하여 제작하였다. 이러한 Buffered deposition 구조는 전계를 줄이기 위한 버퍼층으로 되어 있으며 Buffered deposition 소자의 여러 가지 구조의 Hot carrier 수명을 비교하였으며 열화 특성도 분석하여 10년간의 Hot carrier 수명을 만족함을 증명하였다.

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BC-B Type150K DWT Class Bulk carrier 구조적 특성에 관한 고찰 (A study of Analysis for 150K DWT Class Bulk carrier(BC-B type))

  • 서향덕;김도군;안형준
    • 대한조선학회 특별논문집
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    • 대한조선학회 2015년도 특별논문집
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    • pp.79-84
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    • 2015
  • A BC-B type bulk carrier is rarely built, so the structural characteristics is not reported and familiar so far. The biggest difference between BC-B and BC-A type vessel is applying alternate cargo loading, which density is over $1.0ton/m^3$. In this paper, 150K DWT class BC-B type bulk carrier is calculated and compared with BC-A type vessel, which has same condition such as main dimension and deadweight, about prescriptive rule and FEA based on CSR. And aspect ratio of target vessel is smaller than typical capsize bulk carrier, so 150K and 180K bulk carrier, which applied BC-A type, are also compared to find feature of wide beam vessel.

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SCH 양자우물 레이저 다이오드의 수송기구와 변조응답 특성에 관한 연구 (A Study on the Transport Mechanism of a SCH Quantum-Well Laser Diode and on the Modulation Characteristics)

  • 김종기;정재용;서정하
    • 대한전자공학회논문지TE
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    • 제37권1호
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    • pp.27-34
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    • 2000
  • 본 논문에서는 SCH 양자우물 구조를 가진 레이저 다이오드에서의 캐리어 수송기구와 변조응답 특성에 대해 고찰하였다. 캐리어 수송구조 고찰을 위해 캐리어 밀도분포및 다이오드전류를 계산하였다. 또한 우물내에서의 캐리어 재결합율을 SCH길이의 함수로 도출하였다. 변조응답 특성에서는 캐리어와 광자에 대한 3쌍의 비율 방정식을 도출, 해석하여 SCH 길이에 따른 변조 대역폭과 완화 진동 주파수, 감쇄 비율과 K-factor의 특성에 대하여 고찰하였다.

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저온 분사 공정으로 제조된 Ti 코팅층의 미세조직 및 물성에 미치는 송급 가스의 영향 (Effect of Carrier Gases on the Microstructure and Properties of Ti Coating Layers Manufactured by Cold Spraying)

  • 이명주;김형준;오익현;이기안
    • 한국분말재료학회지
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    • 제20권1호
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    • pp.24-32
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    • 2013
  • The effect of carrier gases (He, $N_2$) on the properties of Ti coating layers were investigated to manufacture high-density Ti coating layers. Cold spray coating layers manufactured using He gas had denser and more homogenous structures than those using $N_2$ gas. The He gas coating layers showed porosity value of 0.02% and hardness value of Hv 229.1, indicating more excellent properties than the porosity and hardness of $N_2$ gas coating layers. Bond strengths were examined, and coating layers manufactured using He recorded a value of 74.3 MPa; those manufactured using $N_2$ gas had a value of 64.6 MPa. The aforementioned results were associated with the fact that, when coating layers were manufactured using He gas, the powder could be easily deposited because of its high particle impact velocity. When Ti coating layers were manufactured by the cold spray process, He carrier gas was more suitable than $N_2$ gas for manufacturing excellent coating layers.

Effect of Different Carrier Agents on Physicochemical Properties of Spray-dried Pineapple (Ananas comosus Merr.) Powder

  • Quoc, Le Pham Tan
    • 대한화학회지
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    • 제64권5호
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    • pp.259-266
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    • 2020
  • The main purpose of this study is to examine the different physicochemical properties of spray-dried products. The carrier agents and powders after the spray-drying process were analyzed for encapsulation yield, moisture content, color parameters, total polyphenol content (TPC), antioxidant capacity (AC), bulk density, flowability, wettability, hygroscopicity, water solubility index (WSI), particle size and microstructure. The spray-drying process was carried out with different carrier agents including maltodextrin (MD) and the combination of maltodextrin and gum arabic (MD-GA) with MA/GA ratio of 70/30, dried at the inlet/outlet air temperature of 160 ℃/70 ℃, 4 bar, airflow rate of 70 ㎥·h-1 and feed flow rate of 750 mL·h-1. The results showed that the different carrier agents have significant influences on the physicochemical properties of the powder produced by the spray-drying method. In there, while the values of recovery efficiency and flowability of spray-dried products from MD are higher than those of spray-dried products from MD-GA combination, the opposite is true for the values of TPC, AC, bulk density and wettability, whereas hygroscopicity and WSI values are equally represented in both products.

포획준위 밀도 예정을 통한 열증착한 일산화규소 박막과 고주파 스퍽터링한 이산화규소 박막의 특성비교 (Comparison of Characteristics Between Thermal Evaporated SiO and rf Sputtered $SiO_2$ Thin Films by Trap Density Measurements)

  • 마대영;김기완
    • 대한전자공학회논문지
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    • 제24권4호
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    • pp.625-630
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    • 1987
  • Thermal evaporated SiO rf sputtered SiO2 thin films were most widely used to the gate oxide of TFTs. In this paper, the difference of trap density and distribution between SiO2 and SiO2 film were studied. TFTs using SiO and SiO2 thin film for the gate oxide were fabricated. The output characteirstics of TFTs and the time dpendencd of the leakage current were measured. Models of the carrier transport and carrier trapping in TFT were proposed. The trap density was obtained by substituting measured value for the equation derived from the proposed model. It was found that rf sputtered SiO2 had more traps at interface than thermal evaporated SiO.

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펨토초급 극초단 펄스레이저에 의해 가열된 실리콘 내의 열전달 특성에 관한 수치해석 (Numerical Analysis on Heat Transfer Characteristics in Silicon Boated by Picosecond-to-Femtosecond Ultra-Short Pulse Laser)

  • 이성혁;이준식;박승호;최영기
    • 대한기계학회논문집B
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    • 제26권10호
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    • pp.1427-1435
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    • 2002
  • The main aim of the present article is numerically to investigate the micro-scale heat transfer phenomena in a silicon microstructure irradiated by picosecond-to-femtosecond ultra-short laser pulses. Carrier-lattice non-equilibrium phenomena are simulated with a self-consistent numerical model based on Boltzmann transport theory to obtain the spatial and temporal evolutions of the lattice temperature, the carrier number density and its temperature. Especially, an equilibration time, after which carrier and lattice are in equilibrium, is newly introduced to quantify the time duration of non-equilibrium state. Significant increase in carrier temperature is observed for a few picosecond pulse laser, while the lattice temperature rise is relatively small with decreasing laser pulse width. It is also found that the laser fluence significantly affects the N 3 decaying rate of Auger recombination, the carrier temperature exhibits two peaks as a function of time due to Auger heating as well as direct laser heating of the carriers, and finally both laser fluence and pulse width play an important role in controlling the duration time of non-equilibrium between carrier and lattice.