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Aluminum oxide (Al₂O₃) is a widely used ceramic material known for its high-temperature stability, which makes it valuable in a variety of industrial applications. The conversion from bulk to surface modification may lead to substantial changes in their thermodynamic properties. Consequently, this study endeavors to resolve the primary thermodynamic properties of Al₂O₃ by employing DFT calculation. The FP-LAPW+lo method is first used in the WIEN2K software to determine the surface of bulk Al₂O₃ with varying thicknesses. The thermodynamic parameters of Al₂O₃ at high pressure and elevated temperature, such as bulk modulus, thermal expansion coefficient, heat capacity, entropy, enthalpy and Debye temperature are investigated with the help of the quasi-harmonic Debye model in the Gibbs2 package. The calculated thermodynamic parameters of the Al₂O₃ agree with earlier findings. The results reveal that with increasing thickness, the thermal expansion coefficient and entropy decrease while the enthalpy increases, indicating that Al₂O₃ can be a suitable candidate for various energy and electronic industrial applications.

By considering the effects of the space charges and domain boundaries in ferroelectric thin films, the thickness dependence of coercive field (E_c) is numerically simulated based on the four-state Potts model with the nearest-neighbor interactions between dipole moments. For large thickness, experimental results where E_c decreases with thickness can be produced from our Monte-Carlo simulation. On the other hand, when the thickness is very small, our simulation gets that E_c increases with thickness by the study of the polarization switching in the film. This gives an explanation of the experimental result by Zhu et al. in J. Appl. Phys.83, 1 (1998) for SBT-BTN film, and a similar report by Bune et al. in Nature391, 874 (1998) for the crystalline film. The critical temperature of the thin film is also discussed.

Porous metal fiber media (PMFM) is a kind of advanced structural and functional material, and it has attracted a wide spread attention owing to excellent sound absorption performance. The sound absorption property of PMFM is mainly influenced by the fiber diameter, the average pore size and thickness of PMFM. In the paper, three stainless steel fibers with the diameters (∅) of 8, 12 and 20 μm were used to make PMFM with the average pore sizes of 10, 20, 30 and 40 μm and the thicknesses of 1, 2 and 3 mm by air-laid and sintering processes. The sound absorption coefficients of PMFM were tested in impedance tube using two-microphone transfer-function method according to ISO 10534-2 and ASTM E1050-98 international standards at room temperature. The results show that when the frequency ranges from 50 Hz to 6,400 Hz in material with the average pore size of 20 μm and the thickness of 3 mm and the fiber diameter of ∅8 μm, the average sound absorption coefficient is the highest.

In this work, the transfer matrix method (TMM) is used to calculate the transmission of superconductor-dielectric 1D photonic crystal with central defect of semiconductor material (GaAs) at high superconductor critical temperature ($T_c)$. It is noticed that there is a red shift to high wavelength region by increasing the thickness of constituent materials. Also we study the effect of changing the incident angle, the doping density of GaAs and the applied pressure. The results show that the sense and change of photonic bandgap and transmittance peaks based on the thickness, incident angle, doping density of GaAs and hydrostatic pressure. In the case of change the thickness and hydrostatic pressure, the PBG and peak of transmittance shifted to higher wavelengths (red shift), while in the case of changing the incident angle and doping density, the PBG and peak of transmittance shifted to shorter wavelengths (blue shift).

As an ionic electroactive polymer, ionic polymer metal composite (IPMC) has unique advantages and is widely used in various fields. However, the output force of IPMC is small, which further limits the application of IPMC. In this study, the Nafion520cs were selected as the preparation solution, and three ion-exchange polymer membranes (IEPMs) with different thicknesses (158, 256 and 383 $\mu$m) were designed and prepared successfully by solution casting technique to study the output force. Then, three platinum electrodes-IPMCs (Pt-IPMCs) were fabricated using electroless plating method. The properties of Pt-IPMCs in terms of morphology, displacements and blocking forces were then evaluated under direct current voltage. The results showed that the prepared ionic membranes were uniform, transparent and flat, without accumulation or bubble. The platinum particles were preferably deposited on the surface, which promoted delivery of current through the IPMCs under the applied voltage, and improved the actuation performance. With the increase of voltage, the maximum displacement and maximum blocking force of the three IPMCs increased first and then decreased. When the voltage is 5.5 V, the maximum displacement for 158 um is 26 mm, while the maximum blocking force of 10.74 mN appears at 6.5 V for 383 um. It is necessary to select suitable thickness of IPMCs to adapt to different working environment and field, which provides a strong basis for further application of IPMCs.

In this work, several designs of lead-based and lead-free perovskite solar cells (PSCs) have been developed and investigated. For the proposed designs, CH₃NH₃PbI₃ (lead-based), FAMASnGeI₃, and CsGeI₃ (lead-free) are used as absorber materials, ${\mathrm{\text{Cu}}}_2\mathrm{\text{O}}$ and NiO have been used as Hole Transport Layer (HTL) materials and TiO₂ as Electron Transport Layer (ETL) materials. ETL materials, in general, have more concern with stability issues and HTL materials have more issues with efficiency improvements. The effect of changing thickness, doping density and defect density of the absorber layer, as well as HTL, defect density of absorber/HTL interface and work functions of front and back contacts on the performance of the proposed devices, are investigated. To enhance the device performance, optimization of the device parameters is performed. After optimization of different parameters, it is observed that the lead-based device structure TiO₂/CH₃NH₃PbI₃/NiO has a maximum efficiency of 29.94%. Even the corresponding lead-free device structure TiO₂/CsGeI₃/NiO exhibits a maximum efficiency of 29.19%. Additionally, this study delved into the influence of altering series and shunt resistances, as well as temperature on the operational characteristics of the lead-free optimized device. Such eco-friendly and cost-effective alternatives as lead-free perovskite cells can be very promising for future work.

Rectangular diaphragm is commonly used as a pressure sensitive component in MEMS pressure sensors. Its deformation under applied pressure directly determines the performance of micro-devices, accurately acquiring the pressure–deflection relationship, therefore, plays a significant role in pressure sensor design. This paper analyzes the deflection of an isotropic rectangular diaphragm under combined effects of loads. The model is regarded as a clamped plate with full surface uniform load and partially uniform load applied on its opposite sides. The full surface uniform load stands for the external measured pressure. The partial load is used to approximate the opposite reaction of the silicon island which is planted on the diaphragm to amplify the deformation displacement, thus to improve the sensitivity of the pressure sensor. Superposition method is proposed to calculate the diaphragm deflections. This method considers separately the actions of loads applied on the simple supported plate and moments distributed on edges. Considering the boundary condition of all edges clamped, the moments are constructed to eliminate the boundary rotations caused by lateral load. The diaphragm’s deflection is computed by superposing deflections which produced by loads applied on the simple supported plate and moments distributed on edges. This method provides higher calculation accuracy than Galerkin variational method, and it is used to analyze the influence factors of the diaphragm’s deflection, includes aspect ratio, thickness and the applied force area of the diaphragm.

Nanocrystalline tin dioxide (SnO₂) thin films have been successfully prepared by sol–gel spin-coating technique on p-type Si (100) substrates. A stable solution was prepared by mixing tin(II) chloride dihydrate, pure ethanol, and glycerin. Temperature affects the properties of SnO₂ thin films, particularly the crystallite size where the crystallization of SnO₂ with tetragonal rutile structure is achieved when thin films that prepared under different aging heat times are annealed at 400${}^{\circ }$C. By increasing aging heat time in the presence of annealing temperatures the FESEM images indicated that the thickness of the fabricated film was directly proportional to solution viscosity, increasing from approximately 380 nm to 744 nm, as well as the crystallization of the thin films improved and reduced defects.

This paper presents a performance analysis of indium-gallium-zinc-oxide (IGZO)- and pentacene-based top-gate-top-contact (TGTC) and bottom-gate-top-contact (BGTC) thin film transistors (TFTs). Extensive simulation has been performed to assess the performances in terms of threshold voltage, subthreshold slope, on-off current ratio, mobility, and figure of merit (FoM). Results indicate a trade-off between mobility and current ratio with respect to the permittivity of the dielectric layer, where tantalum oxide (Ta₂O${}_5)$ provides the optimum result in terms of FoM. The mobility of IGZO is significantly higher for both structures, whereas the current ratio for IGZO is higher than pentacene in the BGTC configuration. Comparing the structural configurations, Ta₂O₅-IGZO-based BGTC achieves $5.92\times$ and $41.8\times$ better mobility and current ratio, respectively, over TGTC structures. The threshold voltage of IGZO-based TFT is observed to increase with the permittivity of the dielectric in TGTC configuration but decrease in BGTC configuration. Meanwhile, the increase in oxide and active layer thicknesses causes a decrease in the threshold voltage. Moreover, both mobility and current ratio improve with a decrease in oxide or active layer thickness. Maximum mobility of 32.30cm²/Vs and a maximum current ratio of 7.54E+08 are achieved for Ta₂O₅-IGZO-based BGTC TFT with 10$\mu$m channel thickness and 5$\mu$m oxide thickness.

The thickness of a knot is the radius of the thickest rope with which the knot could be tied. Basic properties of thickness have been established. However, thickness is difficult to compute for all but a few knot conformations. Thus, a continuous polygonal thickness function is needed to approximate its smooth analogue. The most natural definition yields incorrect estimates on a planar circle. Here, a polygonal thickness function is defined and shown to be continuous and to correctly approximate smooth thickness with an elementary inscribing algorithm. Examples of thickness estimations are also given.

In this paper, we discuss the thickness and quasisymmetric equivalence of a class of fractal sets based on the binary expansion of numbers. We give the sufficient and necessary conditions for the thickness of this kind of sets to be positive, and the necessary and sufficient condition for their quasisymmetric equivalence with the standard Cantor ternary set. This paper also studies the relationship between the thickness and the uniform completeness about the product sets of two sets defined by digit restrictions.

We present an experimental technique to determine the thickness of hydration layers on solid surfaces in aqueous solutions by using an atomic force microscope (AFM). This technique is based on the phenomenon where a small line bending in the AFM force–distance plot of hydrated solid surface in aqueous solutions, may be due to the existence of hydration layers on the tip and the solid surface. The thickness of hydration layers on mica plate immersed in water and NaCl solutions were determined with this technique.

Titanium nitride (TiN) films were deposited on high-speed steel (HSS) using cathodic arc physical vapor deposition (CAPVD) technique. The effect of substrate bias on the crystallography, microstructure, deposition rate, coating thickness and composition, hardness, and adhesion strength of TiN films was investigated. The crystallography of the films was investigated using X-ray diffraction with glazing incidence angle technique. The coating microstructure and elemental composition analysis were carried out using field emission scanning electron microscopy (FE-SEM) together with energy-dispersive X-ray. Crystallography of the films revealed that the effect of substrate bias shows complex symmetry in crystal structure. The resputtering effect due to the high-energy ion bombardment on the film surface influenced the thickness as well as the color of deposited coatings. By increasing the substrate bias from 0 to - 150 V, the size and amount of macrodroplets decreased, whereas the micro-Vickers hardness decreased from 2530 HV_0.05 to 1500 HV_0.05. Scratch tester used to compare the critical loads for coatings and the adhesion achievable at substrate bias of - 50 V was demonstrated, with relevance to the various modes.

An organic thin film transistor (OTFT) based on pentacene was fabricated with SiO₂ as the gate dielectric material. We have investigated the effects of the thickness of pentacene layer and the organic semiconductor (OSC) material on OTFT devices at two different thicknesses. Au metal was deposited for gate, source and drain contacts of the device by using thermal evaporation method. Pentacene thin film layer was also prepared with thermal evaporation. Our study has shown that the change in pentacene thickness makes a noteworthy difference on the field effect mobility (μ_FET), values, threshold voltages (V_T) and on/off current ratios (I_on/I_off). OTFTs exhibited saturation at the order of μ_FET of 3.92 cm²/Vs and 0.86 cm²/Vs at different thicknesses. I_on/I_off and V_T are also thickness dependent. I_on/I_off is 1 × 10³, 2 × 10² and V_T is 15 V, 27 V of 40 nm and 60 nm, respectively. The optimized thickness of the pentacene layer was found as 40 nm. The effect of the OSC layer thickness on the OTFT performance was found to be conspicuous.

Recently, Co(OH)₂ has gained much attention as a promising electrocatalyst. Herein, we synthesized Co(OH)₂-decorated TiO₂ film for electrocatalytic water splitting by a facile and low-cost electrochemistry method, which possessed enhanced performance for oxygen evolution reaction. The results of X-ray diffractometry, transmission electron microscope, scanning electron microscope and X-ray photoelectron spectroscopy verify the successful decoration of Co(OH)₂ electrocatalysts onto the surface of TiO₂. Moreover, photoelectrocatalytic measurements illustrate that the Co(OH)₂-decorated TiO₂ shows higher current density than pure TiO₂ sample. The results obtained in this work give deep insights into the development of photoelectrochemical water splitting.

This paper reports on the fabrication and characterization of polymer optical waveguide. The polymer films were used by dip coating technique. Various waveguide parameters such as refractive index, optical losses, thickness of guide has been reported. Polycyanurate synthesized as planar optical waveguide exhibits low optical loss (< 2 dB/cm) having refractive index 1.592 and excellent absorption spectra in the wavelength range (1540–1560 nm) which makes this polymer promising for integrated optical devices.

We introduce a pair of middle Cantor sets which have stable intersection, while the product of their thickness is smaller than one.

In many microfluidic devices, fluid flow is generated using micropumps like peristaltic micropumps. However the hydrodynamic performance of peristaltic micropumps has not been fully understood and furthermore the effect of dynamic interaction of pumping membrane and fluid flow has not been studied yet. To fill this gap, we studied the hydrodynamic performance of a peristaltic micropump using a numerical model incorporating the fluid-solid interactions. The model consisted of 3 layers; the top layer was the flow channel of 10 μm high, the middle layer was the 5~30 μm thick pumping membrane and the bottom layer was the 3 or 5 pumping chambers. By applying a pumping sequence at a frequency between 16~166 Hz, we calculated flow rate for at least 4 cycles and used the fourth or fifth cycle to evaluate the flow rate per a cycle. We found that the numerical model closely replicated the frequency vs. flow rate relationship of a peristaltic micropump as shown earlier in experimental models. We further found that the flow rate of a peristaltic micropump could be improved by increasing the number of pumping chambers or the thickness of pumping membrane.

The architecture of the biceps femoris (BF) and stiffness of the hamstrings have been found to be associated with injury risk. However, less is known about the architecture of the equally voluminous semitendinosus (ST) and viscoelastic properties of both muscles in individuals with a prior injury. Methods: BF and ST of 15 athletes (previously injured, $n=5$; control, $n=10$) were assessed using ultrasonography and myotonometry. Mean architecture (muscle thickness (MT), pennation angle (PA) and fascicle length (FL)) and viscoelastic measures (stiffness, oscillation frequency and decrement) were compared between the previously injured and contralateral uninjured limb, and between the previously injured and control limbs (mean of both limbs of the control group). Control group participants returned for a duplicate measurement. Findings: Both muscles exhibited high reliability between sessions (intraclass correlation coefficient $(\mathrm{\text{ICC}})=0.89-0.98$) for architecture. BF PA was larger in the previously injured than both uninjured $(+1.1^{\circ },d=0.65)$ and control $(+1.51^{\circ },d=0.71)$. BF fascicles were shorter in the previously injured limb compared to the uninjured $(-0.4\mathrm{\text{cm}},d=0.65)$ and control $(-0.6\mathrm{\text{cm}},d=0.67)$. BF was stiffer in the previously injured compared to uninjured $(+9.2{\mathrm{\text{Nm}}}^{-1},d=1.28)$. ST architecture and viscoelasticity were similar across limbs. Conclusion: A prior hamstring strain injury is associated with a stiffer BF characterized by larger PAs and shorter fascicles.

We present a new stretch forming method for axisymmetric sheet metal parts production. A test bench is designed, fabricated, and mounted on a drilling machine. The blank is fixed rigidly around its periphery in the apparatus, and the forming tool is mounted on the machine spindle. Thus, the control of tool rotational speed, feed rate, and vertical motion from the upper sheet surface becomes possible. Experimental tests are then conducted to form a reference shape. Rotational speed, feed rate, lubrication effect on the final thickness distribution, and geometric profiles are studied. A new multi-pass forming method is also developed and verified. The feed rate decrease, within the range of 0.11–0.18mm/rev, reduces the sheet thinning, while its increase improves the dimensional accuracy. The rotational speed increase, within the range of 112–710rpm, reduces the thickness, while its decrease enhances the geometrical accuracy. Mineral oil seems to be more effective than greases, so the thickness drop is reduced and the dimensional accuracy is improved. The use of the multi-pass strategy avoids the sheet cracking at great forming depth. The decrease in step size, within the range of 0.3–1mm, reduces the thickness minima, while good dimensional accuracy can be obtained in the range of 0.5–1mm.