Thickness Of Top Layer Research Articles

Melting in High‐Pressure Ice Layers of Large Ocean Worlds—Implications for Volatiles Transport

AbstractA high‐pressure ice layer controls the exchange of heat and material between the silicate core and the ocean of Ganymede and Titan. We have shown (Kalousová et al., 2018, http://doi.org/10.1016/j.icarus.2017.07.018) that a temperate (partially molten) layer is always present at the ocean interface. Another temperate layer with a few percent of water may be present at the silicates interface for low values of Rayleigh number. We derive scaling laws to predict the critical value under which this temperate layer exists and the amount of generated melt. The presence of liquid water in contact with silicates was probably limited to the early history, providing a pathway for the transfer of salts and volatiles like 40Ar to the ocean. We also derive scaling laws for the water outflow velocity and for the top temperate layer thickness. These laws can be used to model the global thermal and compositional evolution of large ocean worlds.

The wind work input into the global ocean revealed by a 17-year global HYbrid coordinate ocean model reanalysis

A 17-year (1999–2015) HYbrid Coordinate Ocean Model (HYCOM) reanalysis is used to calculate the wind work to the global oceanic circulation with a focus on the global integral of the wind work on the ageostrophic currents. While the wind work on the geostrophic currents estimate of the study is in good agreement with previous research, our estimation of the wind work on the ageostrophic currents (5.44 TW) is significantly larger than previous estimates. The two main reasons for this difference are: (1) the thickness of HYCOM's first vertical layer is 1 m and thus the surface ageostrophic currents are better represented than those in numerical models that use a thicker top layer; and (2) the reanalysis is forced with hourly surface stresses and thus contains wind work contributions from high frequency wind stress variations compared against previous estimates using daily wind stress.

(Invited) SOI Wafer Technology for Advanced Mos Applications

Emerging microelectronic applications such as Internet-Of-Things (IOT) or mixed signal processing utilize fully depleted MOSFETs built on SOI wafers. Advanced FD devices such as planar MOSFETs with back gate biasing require wafers with thin Si top layer as well as ultra thin BOX layer. To sustain good electrostatic control of the channel and to keep back-gate voltages reasonably low, top Si layer thickness has to be in the 5-10 nm range and BOX thickness needs to be less than 20 nm. The SmartCutTM process is the only technology that allows transferring extremely thin layers of silicon on a wide range of handling substrates with industrial quality. As threshold voltage of FD SOI transistor depends on the thickness of Si layer, the thickness has to be controlled within extremely tight tolerance, typically + /- 5A in full range of spatial frequencies spanning from 10 nm till 300 mm [1]. This creates challenge not only for manufacturing technology, but requires development of new thickness metrology. Introduction of differential reflection microscopy (DRM) [2] allows in-line SOI thickness control in wide range of spatial frequencies with unprecedented throughput and precision. The principles and main applications of DRM will be discussed in the presentation. The key process steps with their influence on specific spatial frequencies are identified. One of the main contributors to mid range frequency (in mm range) thickness variation is the interaction of propagating fracture front with acoustic waves emitted by itself. The experimental verification of this mechanism as well as the results of numerical simulations will be presented. Another critical process in SOI technology is reduction of high frequency thickness variations during finishing steps. Possibilities of using pure surface diffusion as well as chemically enhanced high temperature smoothing will be demonstrated. It will be shown that during high temperature annealing in neutral atmosphere Si surface evolution can be described by Mullings-Herring equation with two extra stochastic terms, responsible for conservative and non-conservative noise, while addition of HCl to the annealing atmosphere changes surface behavior to surface relaxation described by the Edwards-Wilkinson model. General linear 4th order surface development model is proposed covering both mechanisms. Material parameters for the model are determined experimentally in the case of HCl(<1%)/H2 etching of silicon. For some advanced applications base wafer of SOI structure can play functional role in the final device, not limited to a mechanical support. One of such examples is RF SOI substrates specifically designed for RF analog applications, such as front end RF modules in smartphones. Introduction of thermally stable layer with high density of carrier traps between BOX layer and high resistivity Si substrate significantly improves high frequency electrical parameters of the devices built on such substrates [3]. Insertion loss, second harmonic generation of coplanar waveguides as well as quality factors of inductors are such main parameters. Empirical model is presented which allows prediction of the results of RF measurements from simple SRP data.

Effect of organic amendment for the construction of favourable urban soils for tree growth

Ornamental tree planting and establishment in cities is a great challenge because urban soil physical properties are unfavourable to the development of root systems. Our objectives were to measure (i) the effects of organic matter on soil physical properties and tree development, and (ii) the effects of ensuing root development on soil physical properties. Using twenty-four 600-L planted or bare soil containers, we monitored physical properties such as dry bulk density, aggregate stability and near-saturated hydraulic conductivity of our reconstituted soils over a 5.5-year period. A 28-cm thick top layer of sandy loam amended with 40% (v/v) sphagnum peat or organic composts was laid on top of a 28-cm thick layer of sandy loam. Bare-root Ostrya carpinifolia trees were planted in half of the 24 containers, and we monitored shoot development and root biomass and distribution. After 5.5 years, trunk diameter had increased from 59 mm for the control soil to 66 mm for soil mixed with green waste compost, and 74 mm for soil mixed with co-compost of sewage sludge and wood chips. After 4.5 years, trunk diameter was strongly correlated with the total number of axes (r = 0.94) and fine root length density (r = 0.98), and was confirmed as a good indicator of tree development. Fine root development increased stable aggregate formation in all treatments as compared to bare soil. After 4.5 years after planting, the tree root system induced by a high organic matter input had significantly improved near-saturated hydraulic conductivity and was fit to support fertile urban soils.

Tubular hydrophobic ceramic membrane with asymmetric structure for water desalination via vacuum membrane distillation process

A porous ceramic membrane without water wetting is essential for the application of water desalination in membrane distillation. In this study, we report a hydrophobic tubular asymmetric alumina membrane that was modified by grafting hexadecyltrimethoxysilane (C16) molecules. The grafting efficiency and hydrophobicity of the grafted membrane were characterized by its morphology, contact angle and FTIR spectrum, as well as the changes in terms of nitrogen permeance and pure water flux over various pressures. Four kinds of tubular asymmetric alumina membranes were employed in the vacuum membrane distillation (VMD) process. The effects of membrane thickness and pore size on the water flux or salt retention were investigated. The mass transport resistance in substrate was non-negligible and sometimes could be the main contributor to the total mass transport resistance. The membrane with a top layer thickness of 20 μm, pore size of 150 nm and support pore size of 3.2 μm was appropriate in the VMD process. After >1000 min desalination, the permeate flux and salt rejection were maintained as high as at the beginning, i.e., approximately 30 kg·m−2·h−1 and 99.9%, respectively.

Asymmetric polyetherimide membranes (PEI) for nanofiltration treatment

The work aimed to prepare co-polyalkoxyether-imide (PEI) asymmetric membranes to appreciate high flux water selective polymeric membranes appropriate for the separation of organic molecules from aqueous mixtures by nanofiltration. These membranes were prepared under controlled experimental conditions from solvent non-solvent of N,N-dimethylformamide (DMF) – water (H2O) solutions with the corresponding polyamic acid (PAA); after the wet phase inversion in a water bath, the PAA membranes were imidized by thermal treatment. The membrane physical properties, recorded by SEM, were used to optimize the asymmetric membrane preparation to improve the separation properties by tuning the thickness of the dense top layer. The performances of nanofiltration separations were examined in the light of the influence of sets of parameters. The flux of asymmetric PEI membranes increased with an increase of applied pressure. Additional, the permeate flux and membrane permeance for pure water is better than the aqueous organic solutions. Thus, the aqueous organic solution has an influence on decreasing the flux and membrane permeance. PEI membranes showed high rejection for hydrophilic molecules, like polyethylene glycol, with molecular weight ranging from 400 to 6000 Dalton; according to molecular weight, organic rejection of 79–100% were achieved from 500 ppm aqueous solutions of organic compounds.

Solvent resistant nanofiltration membranes using EDA-XDA co-crosslinked poly(ether imide)

A co-crosslinked poly(ether imide) (PEI) material with excellent organic solvent resistance was synthesized using mixed amines of aliphatic ethylenediamine (EDA) and aromatic p-xylylenediamine (XDA), on which the organic solvent nanofiltration (NF) membrane was prepared via the interfacial polymerization between the monomer 1,2,4,5-benzene tetracarbonyl chloride (BTC) and the amine terminals on the co-crosslinked PEI. Structural characterizations indicate that the EDA-XDA co-crosslinking is an effective pathway to modulate the species and the amount of amine terminals on the surfaces, which can in turn affect the toplayer thickness and the surface roughness of the synthesized NF membrane. The results illustrate that the NF membrane prepared on the EDA-XDA (1:1) co-crosslinked PEI (c-P/1E1X) possesses superior separation performance and stability for N,N-dimethylformamide (DMF) solution. Further, the superior solvent resistant NF membrane gly-NF-c-P/1E1X-XDA was synthesized through an additional quick patching-like IP using XDA, with the aid of ethylene glycol filling inside the intermediate pores. The membrane gly-NF-c-P/1E1X-XDA shows the DMF permeance of 6.1 L m−2 h−1 MPa−1 and the Rose Bengal (RB) rejection about 89%, and for a 5 g/L ceftazidime antibiotic DMF solution, the permeance is 4.6 L m−2 h−1 MPa−1 and the ceftazidime rejection is 81%, which is promising to be applied for the recovery of heat sensitivity ceftazidime in DMF solution.

Hybrid method to estimate two-layered superficial tissue optical properties from simulated data of diffuse reflectance spectroscopy.

An iterative curve fitting method has been applied in both simulation [J. Biomed. Opt.17, 107003 (2012)JBOPFO1083-366810.1117/1.JBO.17.10.107003] and phantom [J. Biomed. Opt.19, 077002 (2014)JBOPFO1083-366810.1117/1.JBO.19.7.077002] studies to accurately extract optical properties and the top layer thickness of a two-layered superficial tissue model from diffuse reflectance spectroscopy (DRS) data. This paper describes a hybrid two-step parameter estimation procedure to address two main issues of the previous method, including (1)high computational intensity and (2)converging to local minima. The parameter estimation procedure contained a novel initial estimation step to obtain an initial guess, which was used by a subsequent iterative fitting step to optimize the parameter estimation. A lookup table was used in both steps to quickly obtain reflectance spectra and reduce computational intensity. On simulated DRS data, the proposed parameter estimation procedure achieved high estimation accuracy and a 95% reduction of computational time compared to previous studies. Furthermore, the proposed initial estimation step led to better convergence of the following fitting step. Strategies used in the proposed procedure could benefit both the modeling and experimental data processing of not only DRS but also related approaches such as near-infrared spectroscopy.

Microstructure and nanohardness of Ag and Ni under friction in boundary lubrication

Evolution of deformation microstructure and nanohardness of Ag and Ni after friction in the BL regime was studied. All friction tests were conducted under lubricated conditions using a pin-on-disk rig. Pure fcc metals such as Ag and Ni, with different SFE (16 and 125 mJm−2, respectively), were chosen as pin materials. Cross sectional transmission electron microscopy (TEM) lamellae were prepared from the pins using a focused ion beam (FIB). Using TEM, we analysed the regions of the pins that are in steady state after friction; the friction coefficient (μ) and hardness (Hs) remained unchanged with deformation in the BL regime. After the wear tests, the specimens were cross-sectioned in longitudinal and transverse directions (parallel and perpendicular to the direction of friction). Nanoindentations were performed using a Berkovich diamond tip. A gradient of grain sizes during the friction of Ag and Ni in BL regime was revealed by TEM imaging. Deformation twinning followed by limited recovery within the surface of Ag led to the formation of a relatively thick top layer of ultra-fine equiaxial grains. Thermally activated processes for the rearrangement and annihilation of dislocations are accelerated during the friction of Ni due to high SFE and contact temperature. Cross-sectional microstructures observed normal and parallel to the direction of friction are dissimilar. Steady state values of grain size, ds, and hardness, Hs, after friction in lubricated conditions are explained by the balance between hardening and dynamic recovery in surface layers, and they strongly depend on the SFE and temperature. A correlation between the wear properties (wear coefficient) and total work of deformation during nanoindentation shows a similarity in the nano- and microscales in lubricated friction.

Quality Control of the Concrete of the Supporting Structure of Bridge Reg. No. 333-003 over the Elbe in Přelouč

This paper is introducing results of diagnostic survey of bridge reg. No. 333-003 over the Elbe in Přelouč [1], which included an evaluation of the previous reconstruction carried out in the 1990s [2, 3] and the quality control of the concrete used in the construction after more than 90 years of operation. Visual inspection, comparison of depth of concrete carbonation and thickness of top layer of reinforcement concrete and concrete compression strength are presented in this paper. This paper come into existence with cooperation with the state-funded organization Road Administration and Maintenance of the Pardubice Region.

Wavelength tuning of surface plasmon coupled quantum well infrared photodetectors.

A novel method of detection wavelength tuning for surface plasmon coupled quantum well infrared photodetectors (QWIPs) was demonstrated. By changing of the thickness of the top contact layer, the detection wavelength can be adjusted. The displacement of the detection wavelength is related to the effective dielectric constant of the dielectric layers in the device structure. The peak wavelength moves toward longer wavelength as the contact layer thickness decreases. With a proper match of the 2D metal hole array and the QW absorption region, the responsivity can be kept within a reasonable range for samples with different top contact layer thicknesses.

Mixed matrix membrane of ZSM-5/poly (ether-block-amide)/polyethersulfone for pervaporation separation of ethyl acetate from aqueous solution

The ZSM-5/poly (ether-block-amide) (PEBA)/polyethersulfone (PES) dual layer mixed matrix membranes (MMMs) were prepared for pervaporation (PV) separation of ethyl acetate (EAc) from aqueous solutions. The ZSM-5 zeolite nanoparticles were synthesized by the conventional hydrothermal method and characterized using the XRD, XRF and FESEM analysis. The effect of top layer thickness, PEBA concentration, zeolite loading concentration, feed concentration and temperature on the separation performance of the prepared membranes was investigated. The FTIR, SEM, contact angle and swelling tests were used to characterize the fabricated MMMs. The results indicated that loading ZSM-5 zeolite nanoparticles into the PEBA matrix had a significant influence on the separation performance of the prepared membranes. The ZSM-5/PEBA/PES membrane containing 7.5 wt% ZSM-5 with a top layer thickness of 20 μm, showed the highest separation factor. The total flux was decreased by loading ZSM-5 into the membranes up to 7.5 wt% and further enhancement in the zeolite loading content resulted in increasing the total permeation flux. The best separation factor and total flux of the ZSM-5/PEBA/PES-07.5 membrane were found to be 108.52 and 1895 g m−2h−1, respectively for a feed concentration of 5 wt% EAc and temperature of 50 °C.

Fabrication of package embedded spiral inductors with two magnetic layers for flexible SIP point of load converters in Internet of Everything devices

Inductive DC-DC converters are key elements in power delivery units for the development of Internet of Everything (IoE) architectures made of interconnected networks of smart devices, self-powered from different energy sources. The ultra-low power levels involved in IoE devices in addition to cost reduction of final products requires the development of new technologies for the miniaturization of all the active and passive components. In this paper, a low temperature, cheap and simple two-steps fabrication process of embedded planar inductors with two magnetic layers on a very thin, flexible and lightweight FR4 organic substrate is demonstrated for flexible System in package (SIP) based point of load DC-DC converters in IoE devices. The process uses standard printed wiring board (PWB) copper etching to define the square geometry of the planar inductors and trenches underneath the inductor copper traces. Very thick top and bottom magnetic layers are deposited using stencil printing of an FR4 compatible epoxy-NiZn ferrite composite magnetic material on top of the copper traces and into the trenches. At 30MHz, the permittivity is 3.4 and 6.23 while the dielectric loss tangent is 0.014 and 0.009 for the epoxy and composite magnetic material respectively. The composite material has a permeability of 8.46, a loss tangent value of 0.1 at a frequency of 30MHz and saturates around 0.13 Tesla. The DC resistance varies from 136mΩ to 386mΩ while at 30MHz the AC resistance varies from 1.9Ω to 10.1Ω for an inductance value from 180nH to 715nH, corresponding to an inductance density between 5.69nH/mm2 and 12.47nH/mm2 and a quality factor between 13 and 17. Flexibility and its effect on the electrical parameters of the fabricated inductors is demonstrated through bending tests. A variation of <3% for the DC resistance is obtained for 5mm bend radius. At 30MHz and for a bend radius (both upward and downward) from 3.7mm to 5mm, the flat state (unbent) AC resistance and inductance values (1.9Ω to 10.1Ω for 180nH to 715nH) decrease by 6.5% to 18% and by 2% to 4.4% respectively which increase the self-resonant frequency by 3% to 3.4% and the quality factor by 2.2% to 20%. The characterized inductors are modeled in ANSYS HFSS electromagnetic simulator and simulation results show a good correspondence with the measured inductances and quality factors, which allows a reliable prediction of the inductors behavior for DC-DC converter design and implementation for IoE devices.

Effect of Soil Layering on Coupled Dynamic Response and Active Length of Piles Embedded in Layered Soil Using Cone Model

Dynamic analysis of single pile embedded in two-layered soil has been performed to study the influence of layering on the frequency dependent displacement response and active length under coupled horizontal and rocking vibration. Cone model has been used to determine the dynamic stiffness coefficient of pile. The soil and pile has been assumed to behave as elastic during dynamic loading. It has been also assumed that perfect bond exists between pile surface and surrounding soil medium. The wave generated due to pile vibration transfer to the soil through soil–pile interface and propagates to the infinity. The wave propagation has been modeled with cone model and soil–pile interaction has been incorporated through beam equation. The dynamic response of the pile obtained from the analysis has been plotted against non dimensional frequency to investigate the behavior of pile under such loading condition. The horizontal displacement profile along the depth of pile has been studied for different top layer thickness and homogeneous soil. The results showed that dynamic response is very sensitive to the thickness of the top layer and its properties. The active length of pile increases with the increase in top layer thickness.

Dynamic installation of a torpedo anchor in two-layered clays

The behaviour of a torpedo anchor during dynamic installation in two-layered nonhomogeneous clay sediments was investigated through large-deformation finite-element (LDFE) analyses. Parametric analyses were undertaken varying the top layer thickness and strength ratio between two layers. Results show that the location of the demarcation point between the acceleration and deceleration phases of the anchor in the soil relative to the layer interface is the key factor directing the anchor behaviour in layered soils including the final embedment depth. Broadly speaking, the anchor behaviour in soft-over-stiff clay deposits is somewhat similar to that in single layer clay with strength increasing with depth. In stiff-over-soft clay deposits, the anchor penetrates deeper where the anchor deceleration phase (or the demarcation point) falls within the soft layer. Where the demarcation point lies within the top stiff layer, the anchor penetration depth decreases with increasing strength ratio, and the anchor penetration is terminated between the two layers for strength ratios ≥15. For assessing the anchor embedment depth in two-layered fine-grained ocean sediments in the field, an extended total energy–based method, along with a design expression, is proposed.

Spectral ellipsometry as a method for characterization of nanosized films with ferromagnetic layers

Nanosized films with ferromagnetic layers are widely used in nanoelectronics, sensor systems and telecommunications. Their properties may strongly differ from those of bulk materials that is on account of interfaces, intermediate layers and diffusion. In the present work, spectral ellipsometry and magnetooptical methods are adapted for characterization of the optical parameters and magnetization processes in two- and three-layer Cr/NiFe, Al/NiFe and Сr(Al)/Ge/NiFe films onto a sitall substrate for various thicknesses of Cr and Al layers. At a layer thickness below 20 nm, the complex refractive coefficients depend pronouncedly on the thickness. In two-layer films, remagnetization changes weakly over a thickness of the top layer, but the coercive force in three-layer films increases by more than twice upon remagnetization, while increasing the top layer thickness from 4 to 20 nm.

Preparation of Ba0.5Sr0.5Co0.8Fe0.2O3–δ asymmetric structures by freeze-casting and dip-coating

Asymmetric BSCF (Ba0.5Sr0.5Co0.8Fe0.2O3-δ) samples were successfully obtained in this work by combining the freeze-casting and dip-coating methods. As far as we know, this is the first time that the preparation of asymmetric BSCF structures by the co-use of these two methods is reported in the literature. These materials have attracted a great attention over the past years because they can transport both ions and electrons, and are commonly used as dense mixed ionic-electronic conducting membranes. A homogeneous top layer was observed for freeze-cast supports prepared from slurries containing either 50 or 60wt% BSCF loading. No apparent pores or cracks were observed through the top layer thickness, suggesting that these samples may show a gas selective behavior. Gas permeation tests were carried out at room temperature and feed pressures up to 500kPa.

Observation of two-dimensional superconductivity in bilayers of BaBiO3 and BaPbO3

Besides the cuprate superconductors lead-doped barium bismuthate still attracts intense interest concerning its relatively high critical temperature and the nature of its superconductivity in vicinity to a charge density wave ordered topological insulator. Here we present bilayers of barium bismuthate and barium leadate and find two-dimensional superconductivity at their interfaces well described by current-voltage characteristics compatible with a Berezinskii-Kosterlitz-Thouless transition. Magneto-transport studies independently prove the two-dimensional character of the superconducting properties in these bilayers. The particular dependence of the superconducting transition temperature on the thickness of the barium leadate top layer suggests the formation of the superconducting state to be strain-induced through the interface.

Photoetching method that provides improved silicon-on-insulator layer thickness uniformity in a defined area

A new method to improve the thickness uniformity of a silicon-on-insulator layer in a defined area by photoetching with N-fluoropyridinium salts using a projector was proposed. The method involved initial calculation of the red–green–blue tone distribution from the top silicon layer thickness distribution to be etched using the relationship between the etching depth and red–green–blue tone in a projector. Photoetching was then conducted by projection of an image with the required tone distribution onto a silicon layer surface coated with N-fluoropyridinium salts. The uniformity of silicon layers with a thickness of less than 10nm was improved in an area of approximately 20×20mm by photoetching after prior thinning by thermal oxidation and wet etching. The developed method enables the thickness uniformity in a defined area to be improved while avoiding exfoliation of the silicon layer or the formation of silicon islands in subsequent thermal treatment. In addition, this method has the potential to be cost-effective because it uses a projector.

The Effect of Metallic Co-Coating Thickness on Ferritic Stainless Steels Intended for Use as Interconnect Material in Intermediate Temperature Solid Oxide Fuel Cells

The effect of metallic Co-coating thickness on ferritic stainless steels is investigated. This material is suggested to be used as interconnect material in intermediate temperature solid oxide fuel cells. Uncoated, 200-, 600-, 1000-, and 1500-nm Co-coated Sanergy HT is isothermally exposed for up to 500 h in air at 650 °C. Mass gain is recorded to follow oxidation kinetics, and area-specific resistance (ASR) measurements are conducted on samples exposed for 168 and 500 h. The microstructure of the thermally grown oxide scales is characterized utilizing scanning electron microscopy and energy-dispersive X-ray analysis on broad ion beam-milled cross sections. A clear increase in ASR as a function of Co-coating thickness is observed. However, the increase in ASR, as an effect of a thicker Co-coating, is correlated with thicker (Cr,Fe)2O3 scales formed on these materials and not to an increase in Co spinel top layer thickness.