Trench Split Gate MOSFET's Inductive Switching Kang, H.
I.E.E.E. transactions on electron devices/IEEE transactions on electron devices,
09/2022, Letnik:
69, Številka:
9
Journal Article
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A trench split gate metal-oxide-semiconductor field-effect transistor (MOSFET) inductive switching is analyzed by adopting six-terminal method. Owing to the buried source terminal in the trench ...oxide, conventional three-terminal (gate, source, and drain) analysis has a limitation for investigating the detailed time-dependent current flow in the drift region, channel, as well as each terminal. However, a mixed-mode simulation tools enable us to look into the complicated current flow mechanisms in the device by dividing the gate terminal into the gate-to-source and the gate-to-drain terminals and the source terminal into the <inline-formula> <tex-math notation="LaTeX">{n} + </tex-math></inline-formula>, the <inline-formula> <tex-math notation="LaTeX">{p} + </tex-math></inline-formula>, and the shielded source terminals. The six-terminal method enables us to understand the fundamental turn-on and turn-off switching mechanisms that we have not found out so far from the measurement.
IGBT Reverse Transfer Dynamic Capacitance Kang, H.
I.E.E.E. transactions on electron devices/IEEE transactions on electron devices,
12/2022, Letnik:
69, Številka:
12
Journal Article
Recenzirano
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Small-signal capacitance in every datasheet of insulated gate bipolar transistor (IGBT) is not accurate for understanding IGBT's switching because the bipolar current in the device creates abnormal ...depletion profiles. IGBT's reverse transfer dynamic capacitance is extracted for the first time with a five-contact method. While small-signal capacitance does not allow any current flow in the drift region due to the ground gate, the dynamic capacitance is the output of the time-dependent bipolar carriers during the inductive switching. For this reason, the magnitude and the shape of the dynamic capacitance are quite different from the small-signal capacitance found in most of the commercial datasheet. The discrepancy between the dynamic <inline-formula> <tex-math notation="LaTeX">{C}_{\text {GC}} </tex-math></inline-formula> and the small-signal <inline-formula> <tex-math notation="LaTeX">{C}_{\text {GC}} </tex-math></inline-formula> raises a fundamental question of whether the small-signal <inline-formula> <tex-math notation="LaTeX">{C}_{\text {GC}} </tex-math></inline-formula> in the datasheet is useful for considering the device's dynamic performance.
The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are prognostic factors for various types of cancer. In this study, we assessed the association of NLR and PLR with the ...prognosis of small-cell lung cancer (SCLC) in patients who received the standard treatment.
We retrospectively reviewed patients who were diagnosed with SCLC and treated with platinum-based chemotherapy between July 2006 and October 2013 in Gyeongsang National University Hospital Regional Cancer Center and Changwon Samsung Hospital.
In total, 187 patients were evaluated. Compared with low NLR (<4), high NLR (⩾4) at diagnosis was associated with poor performance status, advanced stage, and lower response rate. Median overall survival (OS) and progression-free survival (PFS) were worse in the high-NLR group (high vs low, 11.17 vs 9.20 months, P=0.019 and 6.90 vs 5.49 months, P=0.005, respectively). In contrast, PLR at diagnosis was not associated with OS or PFS (P=0.467 and P=0.205, respectively). In multivariate analysis, stage, lactate dehydrogenase, and NLR at diagnosis were independent prognostic factors for OS and PFS.
NLR is easily measurable and reflects the SCLC prognosis. A future prospective study is warranted to confirm our results.
Central to the cluster-based routing protocols is the cluster head (CH) selection procedure that allows even distribution of energy consumption among the sensors, and therefore prolonging the ...lifespan of a sensor network. We propose a distributed CH selection algorithm that takes into account the distances from sensors to a base station that optimally balances the energy consumption among the sensors. NS-2 simulations show that our proposed scheme outperforms existing algorithms in terms of the average node lifespan and the time to first node death.
Mass extinctions occur frequently in natural history. While studies of animals that became extinct can be informative, it is the survivors that provide clues for mechanisms of adaptation when ...conditions are adverse. Here, we describe a survival pathway used by many species as a means for providing adequate fuel and water, while also providing protection from a decrease in oxygen availability. Fructose, whether supplied in the diet (primarily fruits and honey), or endogenously (via activation of the polyol pathway), preferentially shifts the organism towards the storing of fuel (fat, glycogen) that can be used to provide energy and water at a later date. Fructose causes sodium retention and raises blood pressure and likely helped survival in the setting of dehydration or salt deprivation. By shifting energy production from the mitochondria to glycolysis, fructose reduced oxygen demands to aid survival in situations where oxygen availability is low. The actions of fructose are driven in part by vasopressin and the generation of uric acid. Twice in history, mutations occurred during periods of mass extinction that enhanced the activity of fructose to generate fat, with the first being a mutation in vitamin C metabolism during the Cretaceous–Paleogene extinction (65 million years ago) and the second being a mutation in uricase that occurred during the Middle Miocene disruption (12–14 million years ago). Today, the excessive intake of fructose due to the availability of refined sugar and high‐fructose corn syrup is driving ‘burden of life style’ diseases, including obesity, diabetes and high blood pressure.
Content List ‐ This is an article from the symposium: “Bioinspirational medicine”.
Separating structure and electrons in VO2Above 341 kelvin—not far from room temperature—bulk vanadium dioxide (VO2) is a metal. But as soon as the material is cooled below 341 kelvin, VO2 turns into ...an insulator and, at the same time, changes its crystal structure from rutile to monoclinic. Lee et al. studied the peculiar behavior of a heterostructure consisting of a layer of VO2 placed underneath a layer of the same material that has a bit less oxygen. In the VO2 layer, the structural transition occurred at a higher temperature than the metal-insulator transition. In between those two temperatures, VO2 was a metal with a monoclinic structure—a combination that does not occur in the absence of the adjoining oxygen-poor layer.Science, this issue p. 1037The metal-insulator transition in correlated materials is usually coupled to a symmetry-lowering structural phase transition. This coupling not only complicates the understanding of the basic mechanism of this phenomenon but also limits the speed and endurance of prospective electronic devices. We demonstrate an isostructural, purely electronically driven metal-insulator transition in epitaxial heterostructures of an archetypal correlated material, vanadium dioxide. A combination of thin-film synthesis, structural and electrical characterizations, and theoretical modeling reveals that an interface interaction suppresses the electronic correlations without changing the crystal structure in this otherwise correlated insulator. This interaction stabilizes a nonequilibrium metallic phase and leads to an isostructural metal-insulator transition. This discovery will provide insights into phase transitions of correlated materials and may aid the design of device functionalities.
In a growing number of galaxy clusters diffuse extended radio sources have been found. These sources are not directly associated with individual cluster galaxies. The radio emission reveal the ...presence of cosmic rays and magnetic fields in the intracluster medium (ICM). We classify diffuse cluster radio sources into radio halos, cluster radio shocks (relics), and revived AGN fossil plasma sources. Radio halo sources can be further divided into giant halos, mini-halos, and possible “intermediate” sources. Halos are generally positioned at cluster center and their brightness approximately follows the distribution of the thermal ICM. Cluster radio shocks (relics) are polarized sources mostly found in the cluster’s periphery. They trace merger induced shock waves. Revived fossil plasma sources are characterized by their radio steep-spectra and often irregular morphologies. In this review we give an overview of the properties of diffuse cluster radio sources, with an emphasis on recent observational results. We discuss the resulting implications for the underlying physical acceleration processes that operate in the ICM, the role of relativistic fossil plasma, and the properties of ICM shocks and magnetic fields. We also compile an updated list of diffuse cluster radio sources which will be available on-line (
http://galaxyclusters.com
). We end this review with a discussion on the detection of diffuse radio emission from the cosmic web.
A microstructure-based integrated crystal plasticity (CP) and continuum damage mechanics (CDM) model is proposed for simulating rolling contact fatigue (RCF). The damage process through the formation ...of the dark etching region (DER) under RCF is implemented, i.e., a DER-CPCDM approach. A hierarchical microstructure of lath martensite is virtually generated by the Voronoi tessellation technique and the theoretical Kurdjumov-Sachs orientation relationship between the prior austenite grains and substructures of lath martensite. Moreover, the micro-plasticity calculated from the polycrystal finite element is coupled with dislocation-assisted carbon migration theory, which enables accurate predictions of the deformation inhomogeneity and the DER/damage distribution at the subsurface. The RCF lifespan of AISI 52100 bearing steel can be predicted within reasonable accuracy, in terms of Weibull probability analysis, when the jump-in-cycles approach is implemented in the DER-CPCDM model. The predicted representative lifespan of the Weibull plot is within an error of 13% when compared with reported experimental data. Process factors, including contact pressure, rotational speed, temperature, carbon concentration, and grain size, are analyzed in a numerical sensitivity study, which can be utilized for potential optimization of the RCF process for improving the performance of materials and parts.
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•An integrated model coupling microstructure-based crystal plasticity and continuum damage mechanics is developed.•Microstructure evolution through dislocation assisted carbon migration, or dark etching region, can be modeled.•Hierarchical martensitic microstructure can be implemented through RVE and Kurdjumov-Sachs relation.•The integrated computational model accurately predicts the lifespan of rolling contact fatigue of steel.
Summary
Background
Coeliac disease (CD), originally thought to be largely confined to Northern Europe and Australasia and uncommon in North America and the Middle East, is now recognised to be ...equally common in all these countries. It is still thought to be rare in the Orient and Sub‐Saharan Africa.
Aim
To assess geographical differences and time trends in the frequency of CD.
Methods
Medline and Embase searches were conducted on 10 November 2012, from 1946 and 1980 respectively, using the key words: coeliac disease or celiac disease + prevalence or incidence or frequency.
Results
There were significant intra‐ and inter‐country differences in the prevalence and incidence of CD. Only 24 ethnic Chinese and Japanese patients have been reported in the English literature. Of CD‐associated HLA DQ antigens, DQ2 occurs in 5–10% of Chinese and sub‐Saharan Africans, compared to 5–20% in Western Europe. DQ8 occurs in 5–10% of English, Tunisians and Iranians, but in <5% of Eastern Europeans, Americans and Asians. The prevalence and incidence of both clinically and serologically diagnosed CD increased in recent years. These geographical and temporal differences seem genuine, although variable indices of suspicion and availability of diagnostic facilities are confounding factors.
Conclusions
Coeliac disease is increasing in frequency, with significant geographical differences. Although few cases have been described to date in the Orient and Sub‐Saharan Africa, there is a significant prevalence of HLA DQ2 and wheat consumption is of the same order as that in Western Europe. CD may therefore become more common in the future in these countries.
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