• Title/Summary/Keyword: bias effect

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The applicability study and validation of TULIP code for full energy range spectrum

  • Wenjie Chen;Xianan Du;Rong Wang;Youqi Zheng;Yongping Wang;Hongchun Wu
    • Nuclear Engineering and Technology
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    • v.55 no.12
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    • pp.4518-4526
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    • 2023
  • NECP-SARAX is a neutronics analysis code system for advanced reactor developed by Nuclear Engineering Computational Physics Laboratory of Xi'an Jiaotong University. In past few years, improvements have been implemented in TULIP code which is the cross-section generation module of NECP-SARAX, including the treatment of resonance interface, considering the self-shielding effect in non-resonance energy range, hyperfine group method and nuclear library with thermal scattering law. Previous studies show that NECP-SARAX has high performance in both fast and thermal spectrum system analysis. The accuracy of TULIP code in fast and thermal spectrum system analysis is demonstrated preliminarily. However, a systematic verification and validation is still necessary. In order to validate the applicability of TULIP code for full energy range, 147 fast spectrum critical experiment benchmarks and 170 thermal spectrum critical experiment benchmarks were selected from ICSBEP and used for analysis. The keff bias between TULIP code and reference value is less than 300 pcm for all fast spectrum benchmarks. And that bias keeps within 200 pcm for thermal spectrum benchmarks with neutron-moderating materials such as polyethylene, beryllium oxide, etc. The numerical results indicate that TULIP code has good performance for the analysis of fast and thermal spectrum system.

Effect of ginseng and ginsenosides on attention deficit hyperactivity disorder: A systematic review

  • Yunna Kim;Ik-Hyun Cho;Seung-Hun Cho
    • Journal of Ginseng Research
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    • v.48 no.5
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    • pp.437-448
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    • 2024
  • Attention deficit hyperactivity disorder (ADHD) is a rapidly increasing neurodevelopmental disorder but currently available treatments are associated with abuse risk, side effects, and incomplete symptom relief. There is growing interest in exploring complementary options, and ginseng has gained attention for its therapeutic potential. This systematic review aimed to assess current evidence on the efficacy of ginseng and its active components, ginsenosides, for ADHD. Eligible studies were identified through searches of PubMed, Embase, Cochrane Library, and Web of Science, up to June 2023. The inclusion criteria included both human and animal studies that investigated the effects of ginseng or ginsenosides on ADHD. The risk of bias was assessed according to study type. Six human studies and three animal studies met the inclusion criteria. The results suggest that ginseng and ginsenosides may have beneficial effects on ADHD symptoms, particularly inattention, through dopaminergic/norepinephrinergicmodulation and BDNF/TrkB signaling. Ginseng and ginsenosides have promising potential for ADHD treatment. Due to limitations in evidence quality, such as the risk of bias and variability in study designs, larger controlled studies are essential. Integrating ginseng into ADHD management may have valuable implications for individuals seeking well-tolerated alternatives or adjunctive therapies.

An Analytical Model for Deriving the 3-D Potentials and the Front and Back Gate Threshold Voltages of a Mesa-Isolated Small Geometry Fully Depleted SOI MOSFET

  • Lee, Jae Bin;Suh, Chung Ha
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.12 no.4
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    • pp.473-481
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    • 2012
  • For a mesa-isolated small geometry SOI MOSFET, the potentials in the silicon film, front, back, and side-wall oxide layers can be derived three-dimensionally. Using Taylor's series expansions of the trigonometric functions, the derived potentials are written in terms of the natural length that can be determined by using the derived formula. From the derived 3-D potentials, the minimum values of the front and the back surface potentials are derived and used to obtain the closed-form expressions for the front and back gate threshold voltages as functions of various device parameters and applied bias voltages. Obtained results can be found to explain the drain-induced threshold voltage roll-off and the narrow width effect of a fully depleted small geometry SOI MOSFET in a unified manner.

A Study on Drapability for Construction of Skirt -Mainly dealing with the Drape-Coefficient and Hem-Effect- (Skirt 구성 면에서 본 Drap 성에 관한 연구 -Drape 계수와 Hem 효과를 중심으로-)

  • Suh Young Suk;Park Young Deuk
    • Journal of the Korean Society of Clothing and Textiles
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    • v.5 no.2
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    • pp.49-53
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    • 1981
  • This study was carried out to investigate the drapability of polyester double jersey skirt Drapability is an important aesthetic properties of fabric on clothing construction, In this thesis weight, shearing, bending and non-isotropic characteristics of fabric were regarded as important factors of drapability, Especially for drapability of skirt, I investigated hem effect on various length of hem and skirt, The results were as follows, 1. The less the weight of fabric was, the greater drapability appeared. On fabrics, large pliability and modulus of shear have good drapability, 2. On clothing cutting, non-isotropic property affected on drapability of clothes remark-ably. Drapability order of clothes was greatest in bias direction, next in wale, course direction, 3. The shorter the skirt length and closer at hem line were the larger the hem effect influence upon the drapability of skirt was.

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High-Performance Flexible Graphene Field Effect Transistors with Ion Gel Gate Dielectrics

  • Jo, Jeong-Ho
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2012.05a
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    • pp.69.3-69.3
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    • 2012
  • A high-performance low-voltage graphene field-effect transistor (FED array was fabricated on a flexible polymer substrate using solution-processable, high-capacitance ion gel gate dielectrics. The high capacitance of the ion gel, which originated from the formation of an electric double layer under the application of a gate voltage, yielded a high on-current and low voltage operation below 3 V. The graphene FETs fabricated on the plastic substrates showed a hole and electron mobility of 203 and 91 $cm^2/Vs$, respectively, at a drain bias of - I V. Moreover, ion gel gated graphene FETs on the plastic substrates exhibited remarkably good mechanical flexibility. This method represents a significant step in the application of graphene to flexible and stretchable electronics.

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Pentacene Thin-Film Transistors with Polyimide/$SiO_2$ Dual Gate Dielectric

  • Imahara, Hirokazu;Kim, Woo-Yeol;Oana, Yasuhisa;Majima, Yutaka
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.972-973
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    • 2007
  • Relationships between field effect mobility and grain size on pentacene thin-film transistors with $polyimide/SiO_2$ gate dielectrics have been studied. 6 kinds of polyimide were used as surface treatment gate dielectric layer. Grain size of the pentacene thin film were between 5 and $30\;{\mu}m$ and depended on the polyimide. The field effect mobility were also depended on the polyimide and the those values were from 0.027 to $0.69\;cm^2/(Vs)$. The field effect mobility tends to increase with increasing the grain size. Precursor type polyimide containing polyamic acid show better mobility of $0.69\;cm^2/(Vs)$ than soluble type polyimide. Bias stress characteristics in air are discussed in the basis of the grain size.

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A Semi-analytical Model for Depletion-mode N-type Nanowire Field-effect Transistor (NWFET) with Top-gate Structure

  • Yu, Yun-Seop
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.10 no.2
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    • pp.152-159
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    • 2010
  • We propose a semi-analytical current conduction model for depletion-mode n-type nanowire field-effect transistors (NWFETs) with top-gate structure. The NWFET model is based on an equivalent circuit consisting of two back-to-back Schottky diodes for the metal-semiconductor (MS) contacts and the intrinsic top-gate NWFET. The intrinsic top-gate NWFET model is derived from the current conduction mechanisms due to bulk charges through the center neutral region as well as of accumulation charges through the surface accumulation region, based on the electrostatic method, and thus it includes all current conduction mechanisms of the NWFET operating at various top-gate bias conditions. Our previously developed Schottky diode model is used for the MS contacts. The newly developed model is integrated into ADS, in which the intrinsic part of the NWFET is developed by utilizing the Symbolically Defined Device (SDD) for an equation-based nonlinear model. The results simulated from the newly developed NWFET model reproduce considerably well the reported experimental results.

Compact Capacitance Model of L-Shape Tunnel Field-Effect Transistors for Circuit Simulation

  • Yu, Yun Seop;Najam, Faraz
    • Journal of information and communication convergence engineering
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    • v.19 no.4
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    • pp.263-268
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    • 2021
  • Although the compact capacitance model of point tunneling types of tunneling field-effect transistors (TFET) has been proposed, those of line tunneling types of TFETs have not been reported. In this study, a compact capacitance model of an L-shaped TFET (LTFET), a line tunneling type of TFET, is proposed using the previously developed surface potentials and current models of P- and L-type LTFETs. The Verilog-A LTFET model for simulation program with integrated circuit emphasis (SPICE) was also developed to verify the validation of the compact LTFET model including the capacitance model. The SPICE simulation results using the Verilog-A LTFET were compared to those obtained using a technology computer-aided-design (TCAD) device simulator. The current-voltage characteristics and capacitance-voltage characteristics of N and P-LTFETs were consistent for all operational bias. The voltage transfer characteristics and transient response of the inverter circuit comprising N and P-LTFETs in series were verified with the TCAD mixed-mode simulation results.

High-Performance Schottky Junction for Self-Powered, Ultrafast, Broadband Alternating Current Photodetector

  • Lim, Jaeseong;Kumar, Mohit;Seo, Hyungtak
    • Korean Journal of Materials Research
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    • v.32 no.8
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    • pp.333-338
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    • 2022
  • In this work, we developed silver nanowires and a silicon based Schottky junction and demonstrated ultrafast broadband photosensing behavior. The current device had a response speed that was ultrafast, with a rising time of 36 ㎲ and a falling time of 382 ㎲, and it had a high level of repeatability across a broad spectrum of wavelengths (λ = 365 to 940 nm). Furthermore, it exhibited excellent responsivity of 60 mA/W and a significant detectivity of 3.5 × 1012 Jones at a λ = 940 nm with an intensity of 0.2 mW cm-2 under zero bias operating voltage, which reflects a boost of 50 %, by using the AC PV effect. This excellent broadband performance was caused by the photon-induced alternative photocurrent effect, which changed the way the optoelectronics work. This innovative approach will open a second door to the potential design of a broadband ultrafast device for use in cutting-edge optoelectronics.

A case study of competing risk analysis in the presence of missing data

  • Limei Zhou;Peter C. Austin;Husam Abdel-Qadir
    • Communications for Statistical Applications and Methods
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    • v.30 no.1
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    • pp.1-19
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    • 2023
  • Observational data with missing or incomplete data are common in biomedical research. Multiple imputation is an effective approach to handle missing data with the ability to decrease bias while increasing statistical power and efficiency. In recent years propensity score (PS) matching has been increasingly used in observational studies to estimate treatment effect as it can reduce confounding due to measured baseline covariates. In this paper, we describe in detail approaches to competing risk analysis in the setting of incomplete observational data when using PS matching. First, we used multiple imputation to impute several missing variables simultaneously, then conducted propensity-score matching to match statin-exposed patients with those unexposed. Afterwards, we assessed the effect of statin exposure on the risk of heart failure-related hospitalizations or emergency visits by estimating both relative and absolute effects. Collectively, we provided a general methodological framework to assess treatment effect in incomplete observational data. In addition, we presented a practical approach to produce overall cumulative incidence function (CIF) based on estimates from multiple imputed and PS-matched samples.