Metallic Cap Research Articles

IMPACT OF SELENIZATION TEMPERATURE AND PRE-ANNEALING TREATMENT ON THE MICROSTRUCTURAL PROPERTIES OF Cu2ZnSnSe4 THIN FILMS GROWN BY RAPID THERMAL PROCESS

The impact of selenization temperature and pre-annealing treatment on the microstructural characteristics of CZTSe thin films were studied. CZTSe thin films were obtained by two-stage process. This processes includes deposition of metallic layers and Se cap layer employing physical vapor deposition systems followed by selenization process performed at elevated temperatures using RTP system with a heating rate of 8°C/s. The compositional properties of CZTSe thin films changed after the heat treatment, but performing pre-annealing treatment before high reaction temperature (550°C) partially prevented element loss in CZTSe compound. Both Raman and XRD measurements confirmed the formation of the kesterite CZTSe phase. However, according to Raman results, CZTSe phase started to decompose into secondary phases such as CTS regardless of temperature. According to the top view images of the samples, the grain structure completely changed with employing heat treatment. Zn-rich phase detected in reacted sample at 550 °C, which indicates decomposition of CZTSe that is confirmed in Raman spectra.

Erratum to: A metallic buildup cap for glass rod dosimeters in radiotherapeutic in vivo dosimetry

Erratum to: A metallic buildup cap for glass rod dosimeters in radiotherapeutic in vivo dosimetry

MR Conditionality of Abandoned Leads from Active Implantable Medical Devices at 1.5T.

During Magnetic Resonance (MR) scans, abandoned leads from active implantable medical devices (AIMDs) can experience excessive heating near the lead-tip, depending on the types of termination applied to the proximal end. The influence of different proximal treatments, i.e., (i) freely exposed in the tissue, (ii) capped with metallic material, and (iii) capped with plastic material on the RF-induced heating are studied. Abandoned leads from a sacral neuromodulation (SNM) system were investigated in this study. The device models, i.e., the transfer functions, for different proximal treatments were developed. These models are then used to assess the in-vivo lead-tip heating inside four virtual human models (FATS, Duke, Ella, and Billie). The RF-induced heating from these abandoned leads with different proximal end treatments are compared with the lead-tip heating of the original AIMD system. The maximum lead-tip heating for abandoned leads using metal cap at the proximal end is lower than that from the original intact AIMD system. Abandoned leads with plastic cap treatment at the proximal end will lead to an average in-vivo temperature that is 3.5 times higher than that from the original intact AIMD system. Therefore, from this study and in terms of the RF-induced heating, the abandoned leads with metallic cap treatment at the proximal end can maintain the MR conditionality of the original AIMD system.Clinical Relevance- The different treatments of proximal end of the abandoned leads from AIMD are studied to ensure that MR Conditional AIMD leads remain MR Conditional when the leads are abandoned in the patients.

Design of Quad feed end-fire microstrip patch antenna for Airborne Systems

To design a quad feed end-fire microstrip patch antenna for airborne systems. Basically these type of antennas are most helpful for avoiding mid-air collisions between aircraft. The microstrip patch antenna is very small in size and it is less in weight. Due to small size and less weight, it offers an easy design and fabrication process. The microstrip patch antenna has radiating patch on one side and ground on the other side. They operate at microwave frequencies. The low profile structure of microstrip antenna offers its wide use in wireless communication. They are used as communication antenna on missiles. Traffic alert and Collision Avoidance System (TCAS) is an airborne system which is utilized to provide the service as last defense equipment for avoiding mid-air collisions between the aircraft. 1.03 GHz and 1.09 GHz are the transmitting and receiving frequencies of the existing TCAS antenna respectively. In airborne systems, low aerodynamic drag is required. FR4 epoxy is chosen as the substrate material whose dielectric constant is 4.4. 1.06GHz is chosen as the design frequency, since it is centre frequency between 1.03GHz and 1.09GHz. Microstrip patch antenna always radiates in the broadside direction which is along elevation plane. Due to metallic cap, microstrip patch antenna can also radiate in the end fire radiation which is along the azimuth plane. The ground plane must have very large dimensions than the patch. This microstrip patch antenna working at UHF (Ultra High Frequency) band is designed and their parameters like gain, directivity, return loss, VSWR (Voltage Standing Wave Ratio) and radiation pattern have been analyzed and simulated using ANSYS HFSS (High Frequency Structure Stimulator).

Magnetic resonance conditionality of abandoned leads from active implantable medical devices at 1.5 T.

During MR scans, abandoned leads from active implantable medical devices (AIMDs) can experience excessive heating at the lead tip, depending on the type of termination applied to the proximal contacts (proximal end treatment). The influence of different proximal end treatments (ie, [1] freely exposed in the tissue, [2] terminated with metal in contact with the tissue, or [3] capped with plastic, and thereby fully insulated, on the RF-induced lead-tip heating) are studied. A technique to ensure that MR Conditional AIMD leads remain MR Conditional even when abandoned is recommended. Abandoned leads from three MR Conditional AIMDs ([1] a sacral neuromodulation system, [2] a cardiac rhythm management pacemaker system, and [3] a deep brain stimulator system) were investigated in this study. The computational lead models (ie, the transfer functions) for different proximal end treatments were measured and used to assess the in vivo lead-tip heating for four virtual human models (FATS, Duke, Ella, and Billie) and compared with the lead-tip heating of the complete MR Conditional AIMD system. The average and maximum lead-tip heating for abandoned leads proximally capped with metal is always lower than that from the complete AIMD system. Abandoned leads proximally insulated could lead to an average in vivo temperature rise up to 3.5 times higher than that from the complete AIMD system. For the three investigated AIMDs under 1.5T MR scanning, our results indicate that RF-induced lead-tip heating of abandoned leads strongly depends on the proximal lead termination. A metallic cap applied to the proximal termination of the tested leads could significantly reduce the RF-induced lead-tip heating.

Chirality Nanosensor with Direct Electric Readout by Coupling of Nanofloret Localized Plasmons with Electronic Transport.

The detection of enantiopurity for small sample quantities is crucial, particularly in the pharmaceutical industry; however, existing methodologies rely on specific chiral recognition elements, or complex optical systems, limiting its utility. A nanoscale chirality sensor, for continuously monitoring molecular chirality using an electric circuit readout, is presented. This device design represents an alternative real-time scalable approach for chiral recognition of small quantity samples (less than 103 adsorbed molecules). The active device component relies on a gold nanofloret hybrid structure, i.e., a high aspect ratio semiconductor-metal hybrid nanosystem in which a SiGe nanowire tip is selectively decorated with a gold metallic cap. The tip mechanically touches a counter electrode to generate a nanojunction, and upon exposure to molecules, a metal-molecule-metal junction is formed. Adsorption of chiral molecules at the gold tip induces chirality in the localized plasmonic resonance at the electrode-tip junction and manifests in an enantiospecific current response.

Parametric Study of a Fully 3D-Printed Dielectric Resonator Antenna Loaded With a Metallic Cap

This article presents a parametric study of a fully 3D-printed hemispherical dielectric resonator antenna (DRA) using low loss dielectric filament and high-conductive filaments jointly with a low-cost customized dual-extruding 3D printer. The parametric study consisted in the design and evaluation of five different hemispherical DRA topologies with different internal shapes and the same overall size, in which the printing infill percentage of the DRA was reduced. A 3D-printed metallic cap was included in the antenna to compensate for the resonant frequency shift in order to maintain its original dimensions. Measurement results show that all evaluated antennas kept the same resonant frequencies and similar radiation patterns while reducing the overall weight of the topology in 22% of the nominal weight.

1D porous silicon photonic crystals comprising Tamm/Fano resonance as high performing optical sensors

We theoretically discuss a new design for the sensing and detection of chemical and biomedical fluids based on the change in their indices of refraction in the refractive index range 1−1.5. The transfer matrix method in cylindrical coordinates and the Bruggeman's effective medium approximation represent the theoretical overview of our study. The metallic cap in front of a ternary porous silicon photonic crystal induces Tamm / Fano states inside the photonic band gap that take part of the resonant peaks in conventional defected PCs. Analysis shows that the spectral positions of these states are very sensitive to changes in refractive index of the void fluids. In particular, the proposed sensor could provide higher performance than many previous 1D photonic crystals sensors. At a void refractive index of 1.1, our design exhibits a sensitivity of 6770 nm/RIU and a quality factor of 662. Therefore, the detection and sensing procedures of chemical and biomedical fluids could be investigated in a rather much efficient, stable and novel technique that has not been applied before.

RETRACTED: Restorations of fresh surfaces for topological materials by de-capping Te

Abstract The topological categorization originates from a depiction of the sequencing of bands around the band gap of the material in comparison to the normal vacuum type band ordering. The structure can either be normal or inverted, and thus topologically trivial or non-trivial. An odd number of Dirac fermions on the surface occurs in this type of material. Time-reversal symmetry is responsible to preserve the surface bands. On the other hand, topological crystalline insulator is protected by mirror symmetry; this system has an even number of Dirac surface state per BZ. Capping layer of Te or Se is necessary due to the high sensitivity of films surfaces to atmospheric pressure. The capping layer works as a protection from oxidation. In Bi2Te3 samples, the bonds between Bi and Te are covalent bonds while the bonds between Te-Te at a certain position are van der Waals bonds. Thereby, the bonds between amorphous Te cap and sample surface is weaker than van der Waals bonds within the sample structure. However, the top boost cleaving method was successful. But, for Pb1-xSnxTe samples the top boost cleaving method unsuccessfully results. The bonds between the metallic Pb1-xSnxTe sample surface and amorphous Te cap are stronger than van der Waals bonds in BaF2 substrate, i.e. F-F van der Waals bonds. In this paper, we present different techniques to recover fresh surfaces, from classical methods (such as sputtering and annealing) working for all types of films and top boost methods, which could be less used due to the strong bonds in some films. Moreover, we were able to recover the immaculate surfaces for non-capped samples. We present here in a systematic study by low energy electron diffraction (LEED), x-ray photoemission spectroscopy (XPS), and angle-resolved photoemission spectroscopy (ARPES).

Enhanced gain and miniaturisation method of stacked dielectric resonator antenna using metallic cap

The authors introduce a miniature and gain enhancement method of dielectric resonator antenna (DRA) using a metallic cap. The structure of the proposed antenna consists of a stacked cylindrical dielectric resonator, a metallic cap that is located on the resonator, and a ground plane. By adjusting the size of the metallic cap while retaining the size of the antenna, the proposed antenna operates in the lower frequency band and shows improved realised gain. As the radius of metallic cap increases, wavelength at z -axis increases and the resonance frequency gets lower. In addition, tangential field at side wall surface increases, which leads to the enhancement of realised gain at resonance frequency. The authors have fabricated a prototype of the antenna for the experimental verification. The simulation results are in a close agreement with the experimental finding.

The effective control of Cu through-silicon via extrusion for three-dimensional integrated circuits by a metallic cap layer

This work demonstrated a new and promising approach to control via extrusion for three-dimensional integrated circuits (3DICs). By depositing 50 nm of Ta as a metallic cap, a significant reduction in both the magnitude and the statistical spread of extrusion was achieved. Thermo-mechanical and interfacial characterization were further carried out to study the mechanism of the observed effect. The results suggested that the Ta cap layer was able to effectively suppress the mass transport at via top surface and along grain boundaries, therefore reducing extrusion.

Observing the evolution of regular nanostructured indium phosphide after gas cluster ion beam etching

Indium phosphide (InP) surfaces develop a pronounced nanostructured texture upon irradiation by energetic ion beams. We have observed the mechanism of nanostructure evolution of InP under irradiation by an Ar gas cluster ion beam (GCIB) using helium ion microscopy (HIM). Initially, metallic indium nanoparticles form on the surface after removal of the top-most oxide layer. These nanoparticles form a mask which shadows the underlying InP. As the ion dose is increased, the masking effect results in substantial nanostructured topography in the form of pillars or nanocones, oriented along the axis of the incident GCIB. The surface sensitivity and high resolution of the HIM facilitates the direct observation of the metallic indium cap at the top of the pillars.

Nonlinearity in the Dynamic Response of Flexural Ultrasonic Transducers

Recent studies of the electro-mechanical behavior of flexural ultrasonic transducers have shown that their response can be considered as three distinct characteristic regions, the first building towards a steady state, followed by oscillation at the driving frequency in the steady state, before an exponential decay from the steady state at the transducer's dominant resonance frequency, once the driving force is removed. Despite the widespread industrial use of these transducers as ultrasonic proximity sensors, there is little published information on their vibration characteristics under different operating conditions. Flexual transducers are composed of a piezoelectric ceramic disc bonded to the inner surface of a metallic cap, the membrane of which bends in response to the high-frequency ceramic vibrations of the ceramic. Piezoelectric devices can be subject to nonlinear behavior, but there is no reported detail of the nonlinearity in flexural transducers. Experimental investigation through laser Doppler vibrometry shows strong nonlinearity in the vibration response, where resonance frequency reduces with increasing vibration amplitude.

Charge transport and accumulation around a spancer insulator for application in HVDC wall bushing

A charge transport model based on ion drift in gases of strong electron affinity has been studied in details and validated against experimental results in air and SF 6 at different pressure and voltage levels. The size of the insulators also differs significantly. The choice of the model parameters, i.e. the solid and gas material properties, is carefully examined with information from existing literature. Results show that using the selected parameters, satisfactory agreement between predicted and measured potential distribution and surface charge density along the insulator surface can be obtained. Computational results for an 1100 kV epoxy spacer for use in HVDC wall bushing show that the concept of electrical conductivity as a material property is no longer valid in strong electric field for the gas surrounding the insulator. The polarity and density of the accumulated surface charge depend on the relative largeness of the electrical conductivity of the insulator material and the effective conductivity of the gas. The nonlinear effect due to ion generation and recombination becomes significant at very high voltage. The metallic cap providing shielding to the triple junction at the high voltage end of the insulator can induce much stronger local electric field near the insulator surface, by a factor of 1.48, if its shape is not optimized against the insulator geometry.

Bandwidth control of cylindrical ring dielectric resonator antennas using metallic cap and sleeve loading

This study investigates the effect of loading a monopole-fed cylindrical ring dielectric resonator antenna using a metallic cap and metallic sleeve on its top and outer surface, respectively. The proposed design exhibits a considerable shift of its upper cut-off frequency (from 13.8 to 20.5 GHz for top loading and 8.2 to 15.9 GHz for outer-surface loading) with varying inner radii (height) of the metallic cap (sleeve), thereby providing the bandwidth (BW) controllability. Fabricated prototypes were measured and compared with simulations and good agreement was obtained. The measured return loss exhibits the desired BW control without affecting the peak gain and radiation pattern of the antenna, which is also confirmed by the measured radiation patterns. The proposed concept can be used to reconfigure the BW of the antenna according to the user's requirements and improve signal-to-noise ratio by rejecting unwanted frequency bands without employing any additional filter section.

New Mineral NamesBubnovaiteCairncrossiteFerraioloiteFontarnauiteGrundmanniteKayrobertsoniteMagnesio-ferri-fluoro-hornblendeMelanarsiteNickeltsumcoriteSanguiteSilicocarnotiteVanadiumWernerkrauseite

This New Mineral Names has entries for 13 new minerals, including bubnovaite, cairncrossite, ferraioloite, fontarnauite, grundmannite, kayrobertsonite, magnesio-ferri-fluoro-hornblende, melanarsite, nickeltsumcorite, sanguite, silicocarnotite, vanadium, and wernerkrauseite. # Bubnovaite* {#article-title-2} L.A. Gorelova, L.P. Vergasova, S.V. Krivovichev, E.Yu. Avdontseva, S.V. Moskaleva, G.A. Karpov, and S.K. Filatov (2016) Bubnovaite, K2Na8Ca(SO4)6, a new mineral species with modular structure from the Tolbachik volcano, Kamchatka peninsula, Russia. European Journal of Mineralogy, 28(3), 677–686. Bubnovaite, (IMA 2014-108), ideally K2Na8Ca(SO4)6, is a new mineral found in fumaroles of the 2012–2013 Tolbachik fissure eruption, Kamchatka peninsula, on the new cinder Naboko cone. The samples of bubnovaite were found in a cavity on the NNE flank of the cone at the depth of 30 cm. The temperature of gases at the sampling location was more than 500 °C. The mineral forms fine-grained, light blue, dendritic aggregates, consisting of colorless, transparent, tabular crystals of maximum dimension 0.14 mm, that were recovered with the aid of a long stick and metallic cap to grab samples from the fumarole vent. Bubnovaite is associated with aphthitalite, (K,Na)3Na(SO4)2, and thenardite, Na2SO4. Crystals of bubnovaite are brittle with a white streak and a vitreous luster. Hardness and density were not measured due to the lack of suitable material. The expected Mohs hardness is 2–3; D calc = 2.656 g/cm3. The mineral is unstable in air and becomes white and non-transparent …

Semiconductor-Metal Nanofloret Hybrid Structures by Self-Processing Synthesis.

We present a synthetic strategy that takes advantage of the inherent asymmetry exhibited by semiconductor nanowires prepared by Au-catalyzed chemical vapor deposition (CVD). The metal-semiconductor junction is used for activating etch, deposition, and modification steps localized to the tip area using a wet-chemistry approach. The hybrid nanostructures obtained for the coinage metals Cu, Ag, and Au resemble the morphology of grass flowers, termed here Nanofloret hybrid nanostructures consisting of a high aspect ratio SiGe nanowire (NW) with a metallic nanoshell cap. The synthetic method is used to prepare hybrid nanostructures in one step by triggering a programmable cascade of events that is autonomously executed, termed self-processing synthesis. The synthesis progression was monitored by ex situ transmission electron microscopy (TEM), in situ scanning transmission electron microscopy (STEM) and inductively coupled plasma mass spectrometry (ICP-MS) analyses to study the mechanistic reaction details of the various processes taking place during the synthesis. Our results indicate that the synthesis involves distinct processing steps including localized oxide etch, metal deposition, and process termination. Control over the deposition and etching processes is demonstrated by several parameters: (i) etchant concentration (water), (ii) SiGe alloy composition, (iii) reducing agent, (iv) metal redox potential, and (v) addition of surfactants for controlling the deposited metal grain size. The NF structures exhibit broad plasmonic absorption that is utilized for demonstrating surface-enhanced Raman scattering (SERS) of thiophenol monolayer. The new type of nanostructures feature a metallic nanoshell directly coupled to the crystalline semiconductor NW showing broad plasmonic absorption.

ON THE PROPAGATION OF OPEN AND COVERED PIT IN 316L STAINLESS STEEL

Pitting corrosion on stainless steel has been widely studied during the last decades, but since it is a stochastic process, it remains difficult to analyze experimentally such a phenomenon. In this work, reproducible single pits were performed on 316L steel by using an experimental setup based on the use of a glass microcapillary to locally supply chloride ions on the steel surface in order to characterize the pit propagation. This original approach allowed obtaining new results about pit propagation. Indeed, it was possible to control the presence of a metallic cap covering the pit by adjusting the experimental parameters (potential – chloride to sulfate ratio – temperature). The presence of this cover was shown to be an important issue concerning the propagation mechanism. It was also possible to study the evolution of both the pit depth and the pit diameter as a function of various parameters. Then, based on the simulation of the current densities at the pit bottom and at the pit aperture, a special attention has been paid for the investigation of the local propagation mechanism.

Gain Enhancement of a V-Band Antenna Using a Fabry-Pérot Cavity With a Self-Sustained All-Metal Cap With FSS

Gain enhancement of a V-band planar antenna in the form of a low-profile Fabry-Perot cavity (FPC) is proposed. This simple design is based on placing a perforated metallic cap, forming a frequency-selective-surface (FSS), over a printed-circuit-board (PCB). An integrated slot-dipole antenna is etched in a thin layer of copper (the ground plane) printed on the other side of the PCB. The metallic cap is self-sustained with surrounded metallic sidewalls. Besides showing the simplicity of such design, we also provide a novel comprehensive analysis using a transmission-line model of a FPC along with the two-port circuit model of the thick FSS. The leaky-wave interpretation for the cavity radiation is also addressed to estimate the effective radiation area and therefore the size of the cap. It will be shown that placing the cap on top of the PCB, besides enhancing the directivity of the feeding-slot reduces its backward radiation. A FPC prototype operating in the 60 GHz wireless band, is fabricated and measured showing good agreement between the simulated and measured results.

Perpendicular Magnetic Anisotropy in MgO/CoFeB/Nb and a Comparison of the Cap Layer Effect

High perpendicular magnetic anisotropy (PMA) has been recently revealed in CoFeB/MgO/CoFeB tunnel junctions if the thickness of CoFeB is <;1.5 nm. However, PMA has been observed in MgO/CoFeB/Ta but not in MgO/CoFeB/Ru, indicating a metallic cap layer effect. In this paper, we extend the study to MgO/CoFeB(0.8-1.8 nm)/Nb(1.3 nm) by sputtering and find that the magnetic behavior of MgO/CoFeB/Nb resembles the magnetic behavior of MgO/CoFeB/Ta. The interface anisotropy constant of both MgO/CoFeB/Ta and MgO/CoFeB/Nb is ~2.2 erg/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> while MgO/CoFeB/Ru has a much weaker interface anisotropy constant ~0.68 erg/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . In addition, the magnetic dead layer (MDL) of MgO/CoFeB/cap (cap = Ta and Nb) is ~0.1 nm while MgO/CoFeB/Ru has a much larger MDL ~0.5 nm. The metallic layer effect on the PMA in CoFeB/MgO-based perpendicular structure is attributed to the interdiffusion during the post-annealing process. The possible correlation between PMA and MDL provides a possible mechanism for the metal layer effect in the CoFeB/MgO-based structures.