• Title/Summary/Keyword: temperature inversion

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High Temperature Characterization of Accumulation-mode Pi-gate pMOSFETs (고온에서 accumulation-mode Pi-gate p-MOSFET 특성)

  • Kim, Jin-Young;Yu, Chong-Gun;Park, Jong-Tae
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.7
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    • pp.1-7
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    • 2010
  • The device performances of accumulation-mode Pi-gate pMOSFETs with different fin widths have been characterized at high operating temperatures. The device fin height is 10nm and fin widths are 30nm, 40nm, and 50nm. The variation of the drain current, threshold voltage, subthreshold swing, effective mobility, and leakage current have been investigated as a function of operating temperatures. The drain current at high temperature is slightly larger than at room temperature. The variation of the threshold voltage as a function of the operating temperature is smaller than that of the inversion-mode MOSFETs. The effective mobility is decreased with the increase of operating temperature. It is observed that the effective mobility is enhanced as the fin width decreases.

0.35㎛ CMOS Low-Voltage Current/Voltage Reference Circuits with Curvature Compensation (곡률보상 기능을 갖는 0.35㎛ CMOS 저전압 기준전류/전압 발생회로)

  • Park, Eun-Young;Choi, Beom-Kwan;Yang, Hee-Jun;Yoon, Eun-Jung;Yu, Chong-Gun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.10a
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    • pp.527-530
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    • 2016
  • This paper presents curvature-compensated reference circuits operating under low-voltage condition and achieving low-power consumption with $0.35-{\mu}m$ standard CMOS process. The proposed circuit can operate under less than 1-V supply voltage by using MOS transistors operating in weak-inversion region. The simulation results shows a low temperature coefficient by using the proposed curvature compensation technique. It generates a graph-shape temperature characteristic that looks like a sine curve, not a bell-shape characteristic presented in other published BGRs without curvature compensation. The proposed circuits operate with 0.9-V supply voltage. First, the voltage reference circuit consumes 176nW power and the temperature coefficient is $26.4ppm/^{\circ}C$. The current reference circuit is designed to operate with 194.3nW power consumption and $13.3ppm/^{\circ}C$ temperature coefficient.

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Calculation of the Viscosity and Diffusion Coefficients for Some Binary Gaseous Mixtures Using the Semi-empirical Inversion Method (반실험적 반전 방법을 이용한 이성분계 기체 혼합물의 점도와 확산계수 계산)

  • Rafiee, H.R.;Heidari, N.
    • Journal of the Korean Chemical Society
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    • v.55 no.4
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    • pp.581-589
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    • 2011
  • Viscosity and diffusion coefficients for the gaseous binary mixtures of benzene- toluene, benzene-phenol and benzene-p-xylene over a wide range of temperature and composition have been predicted using the semi-empirical inversion method. The accuracies are within 3% and 4% for viscosities and diffusion coefficients, respectively.

Candelilla Wax Nanoemulsions Prepared by Phase Inversion Composition (PIC) Method

  • Kim, Eun-Hee;Cho, Wan-Goo
    • Journal of the Korean Applied Science and Technology
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    • v.31 no.2
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    • pp.203-209
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    • 2014
  • Candelilla wax-in-water nanoemulsions stabilized by Span 80/Tween 80 were prepared by the phase inversion composition (PIC) method. Stable nanoemulsions with droplet diameters below 50 nm could be formed when the hydrophilic-lipophilic balance (HLB) values were between 13.5 and 14.5, surfactant concentration was 5.0 wt%, and the surfactant-wax ratio was 1:1. Increased emulsification temperature and cooling rate were found to improve the emulsion properties. Process of PIC (adding aqueous phase to the wax phase) produced smaller droplet size nanoemulsion compared to the process of adding wax phase to the aqueous phase. The stability of these nanoemulsions was assessed by following the change in droplet diameters with time of storage at room temperature (${\sim}25^{\circ}C$). The size remained constant during 2 months storage time.

Cellulose acetate membrane preparation by phase inversion to estimate optimized parameters and its performance study

  • Katariya, Heena N;Patel, Tejal M
    • Membrane and Water Treatment
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    • v.13 no.3
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    • pp.139-145
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    • 2022
  • Development in advanced separation processes leads to the significant advancement in polymeric membrane preparation methodology. Therefore, present research investigated the preparation and characterization of cellulose acetate membrane by phase inversion separation method to determine optimized operating parameters. Prepared CA membrane's performance was been analyzed in terms of % rejection and flux. Investigation was conducted to study effect of different parameters such as polymer concentration, evaporation rate, thickness of film, coagulation bath properties, temperature of polymer solution and of the coagulation bath etc. CA membrane was fabricated by taking polymer concentration 10wt% and 11wt% with zero second evaporation time and varying film thickness over non-woven polyester fabric. Effect of coagulation bath temperature (CBT) and casting solution temperature were also been studied. The experimental results from SEM showed that the surface morphology had been changed with polymer r concentration, coagulation bath and casting solution temperature, etc. Lower polymer concentration leads to lower precipitation time giving porous membrane. The prepared membrane was tested for advanced waste water treatment of relevant effluent stream in pilot plant to study flux and rejection behavior of the membrane.

Decaying temperature and dynamic response of a thermoelastic nanobeam to a moving load

  • Zenkour, Ashraf M.;Abouelregal, Ahmed E.
    • Advances in Computational Design
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    • v.3 no.1
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    • pp.1-16
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    • 2018
  • The decaying temperature and dynamic response of a thermoelastic nanobeam subjected to a moving load has been investigated in the context of generalized theory of nonlocal thermoelasticity. The transformed distributions of deflection, temperature, axial displacement and bending moment are obtained by using Laplace transformation. By applying a numerical inversion method, the results of these fields are then inverted and obtained in the physical domain. Also, for a particular two models, numerical results are discussed and presented graphically. Some specific and special results are derived from the current study.

Improving Usage of the Korea Meteorological Administration's Digital Forecasts in Agriculture: I. Correction for Local Temperature under the Inversion Condition (기상청 동네예보의 영농활용도 증진을 위한 방안: I. 기온역전조건의 국지기온 보정)

  • Kim, Soo-Ock;Kim, Dae-Jun;Kim, Jin-Hee;Yun, Jin I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.15 no.2
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    • pp.76-84
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    • 2013
  • An adequate downscaling of the official forecasts of Korea Meteorological Administration (KMA) is a prerequisite to improving the value and utility of agrometeorological information in rural areas, where complex terrain and small farms constitute major features of the landscape. In this study, we suggest a simple correction scheme for scaling down the KMA temperature forecasts from mesoscale (5 km by 5 km) to the local scale (30 m by 30 m) across a rural catchment, especially under temperature inversion conditions. The study area is a rural catchment of $50km^2$ area with complex terrain and located on a southern slope of Mountain Jiri National Park. Temperature forecasts for 0600 LST on 62 days with temperature inversion were selected from the fall 2011-spring 2012 KMA data archive. A geospatial correction scheme which can simulate both cold air drainage and the so-called 'thermal belt' was used to derive the site-specific temperature deviation across the study area at a 30 m by 30 m resolution from the original 5 km by 5 km forecast grids. The observed temperature data at 12 validation sites within the study area showed a substantial reduction in forecast error: from ${\pm}2^{\circ}C$ to ${\pm}1^{\circ}C$ in the mean error range and from $1.9^{\circ}C$ to $1.6^{\circ}C$ in the root mean square error. Improvement was most remarkable at low lying locations showing frequent cold pooling events. Temperature prediction error was less than $2^{\circ}C$ for more than 80% of the observed inversion cases and less than $1^{\circ}C$ for half of the cases. Temperature forecasts corrected by this scheme may accelerate implementation of the freeze and frost early warning service for major fruits growing regions in Korea.

Inversion Phenomena of Temperature in the Southern Sea of Korea (한국 남해의 수온역전현상)

  • KIM Hee-Joon;YUG Sang-Sup
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.16 no.2
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    • pp.111-116
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    • 1983
  • Temperature inversions are investigated by using the oceanographic data (1965-1979) obtained in the Southern Sea of Korea. The temperature inversions in winter occur about six times more frequently than those in sumner. In the west region of the Southern Sea, the inversions are found at any depth in winter. In the east region of the Southern Sea, however, they usually appear in surface layer in winter. Such inversion phenomena in winter can be explained by surface cooling effects associated with a net heat loss at the sea surface and a southward advection of surface cold water due to north-westerly monsoon. In summer the inversion layers are usually formed below the thermocline in the west region of the Southern Sea, and in surface layer in the east region. The former results from the mixing between the Tsushima Warm Current and the Yellow Sea Bottom Cold Water, and the latter is generated by an offshore flow of cold water near coast due to southwesterly wind.

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