This letter investigates the effect of repeated uniaxial mechanical stress on bias-induced degradation behavior in polycrystalline thin-film transistors (TFTs). After 100 000 iterations of ...channel-width-direction mechanical compression, serious threshold voltage degradation and an abnormal hump are observed. Simulation indicates that the strongest mechanical stress occurs at both sides of the channel edge, between the polycrystalline silicon and gate insulator. Since these stress points produce oxide traps in the gate insulator, the degradation of threshold voltage shift and parasitic current path can be attributed to electron trapping at these intense mechanical stress points. In addition, the degradation becomes serious with diminishing TFT size.
This numerical analysis investigated the effects of heat and mass transfer characteristics on the mixed convection flow of non-Newtonian fluids over the vertical wedge in a saturated porous medium ...with Soret/Dufour effects and internal heat generation. The numerical modeling of this problem has attracted considerable attention from researchers because it has practical applications in biological sciences, electronic cooling, advanced nuclear systems, etc. The internal heat generation is assumed to be an exponential decaying form. The power-law model of Ostwald–de Waele for non-Newtonian fluids is considered. The surface of the vertical wedge is kept at variable wall temperature and concentration. In the analysis of mixed convection, which included free convection and forced convection, parameter varies from 0 (pure free convection) to 1 (pure forced convection). The transformed equations are obtained by using a suitable coordinate transformation, and then, Keller box method is utilized to solve the non-similar equations. Comparisons with data published previously showed good agreement. Both the local Nusselt number and the local Sherwood number increase with increasing the exponent of variable wall temperature/concentration. Increasing the internal heat generation coefficient decreases (increases) the local Nusselt (Sherwood) number. As the power-law index is increased, the local Nusselt and Sherwood numbers are decreased.
Mammalian SWI/SNF also called BAF (Brg/Brahma-associated factors) ATP-dependent chromatin remodeling complexes are essential for formation of the totipotent and pluripotent cells of the early embryo. ...In addition, subunits of this complex have been recovered in screens for genes required for nuclear reprogramming in Xenopus and mouse embryonic stem cell (ES) morphology. However, the mechanism underlying the roles of these complexes is unclear. Here, we show that BAF complexes are required for the self-renewal and pluripotency of mouse ES cells but not for the proliferation of fibroblasts or other cells. Proteomic studies reveal that ES cells express distinctive complexes (esBAF) defined by the presence of Brg (Brahma-related gene), BAF155, and BAF60A, and the absence of Brm (Brahma), BAF170, and BAF60C. We show that this specialized subunit composition is required for ES cell maintenance and pluripotency. Our proteomic analysis also reveals that esBAF complexes interact directly with key regulators of pluripotency, suggesting that esBAF complexes are specialized to interact with ES cell-specific regulators, providing a potential explanation for the requirement of BAF complexes in pluripotency.
We fabricated waveguide resonators with high thermal stability using tantalum pentoxide thin film covered with PECVD silicon dioxide cladding. Without complex athermal design, low temperature ...dependence of 7.4 pm/°C and 8.15 pm/°C were measured in waveguide Bragg gratings (WBG) and Fabry-Perot resonator sandwiched by a pair of identical WBG mirrors, respectively. Suggested by semi-analytical perturbation calculations, the athermal properties of tantalum pentoxide waveguide grating are attributed not only to the low thermo-optical coefficient in tantalum pentoxide thin film but also to the strong chromatic dispersion of the guided modes. Guidelines are proposed to design waveguide-based frequency devices of low thermo-optical effect without complex athermal design.
The extent of the poly-silicon crystalline protrusion, a result of differences in excimer laser annealing (ELA), affects the performance and reliability of thin-film transistors (TFTs). This study ...investigates the degradation mechanism of the low-temperature polycrystalline silicon (LTPS) TFT devices with differences in crystalline protrusion under self-heating stress (SHS). Higher ELA energy will induce higher protrusion height in the interface between the poly-silicon and gate insulator (GI). This surface morphology leads to serious charge trapping into the GI layers; in contrast, the smallest degradation after SHS can be seen in the devices with the lowest protrusion height. This indicates that the degradation is caused by the surface morphology between the poly-Si and GI interface. In addition, the COMSOL simulation results confirm that the large electric field in the GI layer appears in the rough surface morphology devices; therefore, choosing the appropriate ELA energy of the poly-Si is beneficial for the applications of the driving TFT in organic light-emitting diode (OLED) display in the manufacturing industry.
The problem of cross diffusion (Soret/Dufour) and internal heat generation effects on combined convection flow of non-Newtonian fluids flow over the vertical wedge in a saturated porous medium with ...the entire regime is solved numerically. The internal heat generation is assumed to be an exponential decaying form. The power law model of Ostwald-de-Waele for non-Newtonian fluids is considered here. The entire regime of the combined convection is included, as the combined convection parameter varies from 0 (pure free convection) to 1 (pure forced convection). The transformed equations are obtained by using a suitable coordinate transformation and then Keller box method (KBM) is utilized to solve the non-similar equations for the variable heat flux and variable mass flux (VHF/VMF) conditions. Comparisons with the previously published article are performed and the good agreement is achieved. The main numerical results for the dimensionless temperature and concentration distributions, the local Nusselt and Sherwood numbers are obtained.
This paper clarifies the correct transmission mechanism, misattributed in the previous research, of a hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) device. Complete drain ...current-gate voltage (<inline-formula> <tex-math notation="LaTeX">{I}_{\text {D}} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">{V}_{\text {G}} </tex-math></inline-formula>) transfer characteristics including the forward and backward gate sweeps (gate voltage carried out in the OFF-state <inline-formula> <tex-math notation="LaTeX">\to </tex-math></inline-formula> on-state and the ON-state <inline-formula> <tex-math notation="LaTeX">\to </tex-math></inline-formula> OFF-state) are performed, and the physics models of an energy-band schematic are clearly explained. This paper reveals that the <inline-formula> <tex-math notation="LaTeX">{I}_{\text {D}} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">{V}_{\text {G}} </tex-math></inline-formula> curve stretch-out behavior of the subthreshold region is due to the leakage of the Poole-Frenkel region. At the Poole-Frenkel regions, electrons transfer to the drain terminal, and holes remain in the valance band of the a-Si:H bulk. The remaining holes represent the positive voltage and cause the electron barrier height lowering. This causes an increase in subthreshold current of the subthreshold region. Finally, three experiments are performed to prove the correctness of these models, and the a-Si TFTs device improvement methods will be proposed to enhance the stability and performance of product of the a-Si TFTs.
Purpose
The aim of this study is to identify sources of distress among cancer patients attending rehabilitation in the community.
Methods
Participants were 430 patients recruited from a cancer ...rehabilitation center in Singapore between 2017 and 2018, who had rated their distress using the distress thermometer (DT) and indicated associated problems on the problem list. Chi-square tests were used to detect differences in the reported symptoms among three age groups. Exploratory factor analysis was used to identify symptom clusters. Partial correlational analysis was then performed to examine the relationship between distress, symptom clusters, and age controlling for gender and cancer type.
Results
About 30% of the participants reported distress ≥ 5 on the DT (mean 3.3 ± 2.5), and the mean number of problems endorsed was 8 ± 6. A higher total number of reported problems (
r
= .63) and younger age (
r
= − .21) were associated with increased distress. The younger age group also reported more problems surrounding emotions, finance, work/school, children-related issues, and physical symptoms such as sleep and nausea. Of the 12 factors identified, 9 psychosocial and physical symptom clusters correlated with distress (
r
ranging from .12 to .41). All results were statistically significant after adjustment (
p
≤ 0.05).
Conclusion
Younger survivors are more at risk of distress and report greater role functioning concerns related to childcare, partner relationship, and work participation. Age-tailored and multimodal interventions may be necessary to adequately address age-related differences and help coordinate management of multiple symptom clusters across physical and psychosocial concerns.
In this study, a novel structural device, named as a wing-shaped TFT, is proposed and is demonstrated to prevent fast deterioration under mechanical bending in foldable devices. After long-term ...mechanical bending, standard low-temperature polysilicon TFTs exhibit instability behaviors such as sub-channel formation, serious threshold voltage shifts, an on-current (ION) increase, and an off-current (IOFF) decrease. These phenomena are believed to be due to additional oxide traps along the channel-width edges of the gate insulator after bending. In order to suppress this degradation, a wing-shaped structure is proposed. By extending the active layer, degradation regions are shifted away from the main channel. Therefore, the reliability of the devices is enhanced. The transfer characteristics show enhanced electrical behavior after being held for 48 hours in a static bent condition, with an 88% drop in threshold voltage shift as well as a 55% decrease in subthreshold swing degradation, proving better durability of the foldable TFT to bending stress for devices with these wings. Time-dependent transfer characteristics, a COMSOL simulation, and device geometry are discussed to support our findings.
This letter investigates flexible polycrystalline silicon thin film transistor performance variation due to different buffer layer thicknesses. In flexible electronics, thermal expansion stress ...during device fabrication is inevitable. A thicker SiO 2 buffer demonstrates better endurance to thermal expansion stress from the polyimide substrate during device annealing. However, if the SiO 2 buffer thickness is above a critical point, its weak heat dissipation capability causes the optimal ELA crystallization condition to shift. A thermal expansion stress simulation and TEM photos were utilized to verify performance variation. Furthermore, a similar trend was observed in electrical characteristics after negative bias temperature instability.
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