Input Power Ratio Research Articles

Organosilicon-Based Thin Film Formation in Very High-Frequency Plasma Under Atmospheric Pressure

Owing to recent interest in the production of flexible devices, it is necessary to develop a more convenient approach in which silicon (Si) thin film transistors (TFTs) are fabricated directly onto the flexible substrates at low substrate temperatures. Unfortunately, the physical limitations of conventional plasma-enhanced chemical vapor deposition (PECVD) under low pressures becomes a critical obstacle. In this study, Si film deposition using PECVD under atmospheric pressure excited by very high-frequency electrical power was investigated to overcome this issue. Tetramethylsilane [Si(CH3)4] is used as a source gas that is much safer than silane (SiH4) gas. We investigated the effects of the reactive gas concentration and specific energy (the ratio of input power to unit volume of the reaction gas) on carbon incorporation into the resultant films. Based on the results, we discuss the possibility of forming Si films with sufficiently low carbon content, which is applicable to Si TFTs.

Numerical simulation analysis and orthogonal experiment optimization of the factors affecting plasma gasification of oil-based drilling cuttings

Plasma gasification technology is a harmless and resourceful solid waste treatment method. As a hazardous waste, studying the plasma gasification treatment of oil-based drilling cuttings has practical significance. Therefore, this paper uses Aspen Plus to establish a plasma gasification model. Based on model validation, the effects of input power, oxygen equivalence ratio, and carrier gas type on the plasma gasification process of oil-based drilling cuttings were discussed. In addition, by designing a quadratic regression orthogonal experiment, a nonlinear quadratic regression equation was established between the three factors of gasification pressure, input power, and equivalence ratio, as well as different gasification indicators, namely gas yield, lower heating value, and gasification efficiency. By solving the equation, it was found that when the gasification power is 70 kW, the gasification pressure is 10 atm, and the equivalence ratio is 0.1, the gas yield reaches its maximum of 0.74 kg/m3; When the gasification power is 15 kW, the gasification pressure is 10 atm, and the equivalence ratio is 0.1, the lower heating value of gas production reaches its maximum of 9.68 MJ/m3; When the gasification power is 15 kW, the gasification pressure is 1 atm, and the equivalence ratio is 0.1, the gasification efficiency reaches its maximum of 37.6%. At the same time, it was found that the influence of gasification pressure, input power, and equivalence ratio on gasification indicators was ranked in descending order as equivalence ratio, input power, and gasification pressure. The above research provides certain reference values for the practical operation of plasma gasification of oil-based drilling cuttings.

A phase-locked transit time oscillator operated with low external guiding magnetic field

A phase-locked coaxial transit time oscillator is designed for microwave sources with a small volume and low magnetic field in high-power microwave coherent combining. The oscillator achieves controlled output phase through pre-modulation of electron beams. To improve the phase-locked performance with low magnetic fields, a reentrant input cavity is used to ensure the stability and uniformity of the electric field. Electric field uniformity of the buncher and extractor is also improved. To reduce the device volume, a reflector with pre-modulation function is used to reduce the axial size of the device. Particle-in-cell simulation shows that 5 kW input power is sufficient to lock-in a 610 MW output microwave, with a conversion efficiency of 40.6% at 0.66 T. The input power ratio reaches −50.8 dB. Simulation results demonstrate that the device can still achieve phase locking with a magnetic field as low as 0.5 T.

Excitation Flexibility of On-Antenna Power Combining

In this letter, a design methodology is proposed for on-antenna power combining with flexible input power ratios. Designing multi-feed antennas with direct power combining requires weighted driving signals to match the field distribution at the resonant mode of the antenna, imposing serious restrictions on their implementation. To overcome this drawback, we proposed a method to relax the excitation criterion by altering the impedance matching conditions of the multi-feed antenna, giving the RF designers a degree of freedom. First, an eigenanalysis method is employed to extract the active impedance values for each port of the antenna. Then, according to a preferred input power distribution, proper impedance matching is built based on the active impedance values. The resulting multi-feed antenna resembles the single-feed antenna in terms of the radiation performance with desired driving signals. A series of four-feed slot antennas were fabricated to validate the proposed method. Simulation and measurement results show that under different excitation scenarios the radiation performance of the antenna remains intact, demonstrating the flexibility for on-antenna power combining.

The grain refinement of Mg alloy subjected to dual-frequency ultrasonic melt treatment: A physical and numerical simulation

Ultrasonic melt processing of magnesium (Mg) alloys has received widespread attention. However, the cavitation behavior and microstructure evolution are difficult to be directly observed in high temperature melts. In this work, single-frequency ultrasonic field (SUF) and dual-frequency ultrasonic field (DUF) were introduced into succinonitrile (SCN) melt and real-time images of dendrite growth and evolution were captured to explore the regulation mechanism of DUF on melt solidification structure. Numerical simulation and corresponding experiments were performed to investigate the acoustic pressure distribution and cavitation area of DUF in Mg alloy melt. Ultrasonic treatment increased the SCN dendrite growth rate and refined the solidification microstructure, and a higher efficiency was achieved by DUF when compared to SUF when the total electric power was the same. DUF decreased sound pressure attenuation and enlarged cavitation area. A result of this improvement was that its grain refinement efficiency was 13.8% and 25.6% higher than SUF at 15 kHz and 20 kHz, respectively. The input power ratio plays a crucial part in improving the grain refinement efficiency of DUF. While ensuring the symmetrical distribution of cavitation area, the grain refinement efficiency can be significantly optimized by appropriately increasing the power share of 15 kHz ultrasound is optimal at a power ratio of 2:1.

System and Component Level Design Procedure for High Reduction Ratio Pericyclic Drive

The focus of this work is to integrate component-level design analyses developed for different machine elements of a twin pericyclic drive into a comprehensive design decisions framework. The integrated system loads, bearing loads, and tooth contact analysis procedure is used for designing a prototype for minimum weight within the constraints posed by assembly, component life, and system efficiency. Simultaneous sizing of the gears, bearings, and shafts was performed for given input power, speed, and reduction ratio. The effect of inertial loads due to nutational gear motion is significant on support bearing loads, and the gear bodies are designed to minimize these loads. It was demonstrated that a torque density greater than 50 Nm/kg can be achieved for a low Technology readiness level (TRL) pericyclic transmission prototype design. The test article is designed to operate at a 50-HP, 5000 RPM input with a speed reduction ratio of 32:1 and system efficiency greater than 93%.

이중 안테나 제어에 따른 유도결합 N₂/NH₃/SiH₄ 플라스마의 전자 및 라디칼 밀도 분포

Low temperature N₂/NH₃/SiH₄ plasma is used to deposit hydrogenated silicon nitride(SiN<SUB>x</SUB>:H). In this process, the main factor influencing the quality of the deposited film is the active species, such as SiH<SUB>x</SUB> and NH<SUB>x</SUB> radicals. In the conventional methods, it was insufficient to explain the correlation between generation of active species and the process parameters. So, a fluid model of 2D axis-symmetry based on dual antenna inductively coupled plasma (ICP) source using N₂/NH₃/SiH₄ gas mixture has been developed for SiN<SUB>x</SUB>:H film deposition. The gas mixture model was comprised of 57 species, 195 chemical reactions and 16 surface reactions. The ratio of input power between independent antenna system affects the electron and SiH<SUB>x</SUB>, NH<SUB>x</SUB> radical generation. And it was observed that the spatial uniformity of electron and radical density increases when the independent input power of dual antenna system is set to 500:500W.

Property evaluation of TixZrNbTaFeBy high entropy alloy coatings: Effect of Ti and B contents

High entropy alloy (HEA) coatings have been widely explored due to their unique properties as compared with conventional alloy coatings. In this work, an equimolar TiZrNbTaFe HEA target and a TiB2 target were used to fabricate six TixZrNbTaFeBy HEA alloys with different Ti and B contents. The Ti and B contents were increased by adjusting the input power ratios of TiZrNbTaFe HEA and TiB2 targets. The (Ti + B)/(Zr + Ta + Nb + Fe) ratio of the coatings increased from 0.91 to 11.61 as the TiB2 to ZrTiNbTaFe HEA target input power ratio increased from 1.43 to 20. The TixZrNbTaFeBy coating kept its amorphous structure while the (Ti + B)/(Zr + Ta + Nb + Fe) ratio was less than 11.61. A nanocomposite microstructure consisting of TiB2 nanocrystallites embedded in an amorphous TiZrNbTaFe matrix was obtained for the Ti15.2Zr0.9Nb1Ta1.2Fe1.1B33.8 coating. The hardness of TixZrNbTaFeBy coatings increased with increasing Ti and B contents. Good adhesion properties were found for coatings with higher (Ti + B)/(Zr + Ta + Nb + Fe) ratios. Each amorphous TixZrNbTaFeBy coating enhanced the corrosion resistance of bare 304 stainless steel substrate because of the dense microstructures to block the attack of corrosive electrolytes. The nanocrystalline TiB2 structure found in the Ti15.2Zr0.9Nb1Ta1.2Fe1.1B33.8 coating exhibited a potential application as a protective coating in harsh environments due to its high hardness of 21 GPa, excellent adhesion, good wear resistance, and adequate anticorrosion property.

Unravelling CO2 capture performance of microalgae cultivation and other technologies via comparative carbon balance analysis

Microalgae cultivation, absorption, adsorption, and membrane separation are widely applauded as promising technologies to sequester CO2 from flue gas. Herein, comparative carbon balance was used to elucidate their CO2 capture performance in the aspects of CO2 emission rates (direct, indirect, total, and net), CO2 removal efficiencies (apparent and actual), and CO2 removal rate per power input ratio. Screening criteria for effective CO2 capture system rule out energy-intensive sorption processes, put forward low energy membrane separation, and disclose alterable competency of microalgae cultivation. For CO2 capture from flue gas, microalgae (Chlorella vulgaris) cultivation in open raceway ponds was only inferior to membrane separation. To improve microalgal CO2 capture, the sensitivity analysis was performed by replacing original microalgae species (C. vulgaris) or cultivation system (open raceway pond). The microalgal CO2 capture in open raceway ponds became worse following the substitution of C. vulgaris with alternatives (Botryococcus braunii, Chlorella kessleri, Chlorella pyrenoidosa, Scenedesmus obliquus, Spirulina sp., or Tetraselmis suecica). For microalgal (C. vulgaris) CO2 capture, the competent cultivation systems included open raceway pond and airlift photobioreactor, while the bubble column, flat panel, or tubular photobioreactors were classified as non-competent systems. In short, microalgal (C. vulgaris) CO2 capture was technically feasible in open raceway pond or airlift photobioreactor; further, the use of airlift photobioreactor was preferred for better CO2 capture and microalgae biomass production. Due to the necessity of a huge working volume, the low scalability of microalgae cultivation could hamper the industrial application of microalgal CO2 capture from flue gas.

Asymmetric Doherty Power Amplifier with Input Phase/Power Adjustment and Envelope Tracking

In this paper, the design and implementation of a Doherty power amplifier (DPA) are proposed using gallium nitride high electron mobility transistors (GaN HEMTs). Class-F and Class-C modes are combined to obtain an asymmetric DPA. The precise active load-pull controlling of fundamental and harmonic terminations of the DPA is simulated and analyzed, including the parasitics of the transistors. The measurements of the DPA with the phase difference, input power ratio adjustment, and envelope tracking of the auxiliary PA are discussed in detail in order to achieve a competitive performance. A greater than 63% drain efficiency is obtained within the 10-dB input power dynamic range at 2.1 GHz. The peak of the drain efficiency reaches 73%, with a corresponding output power of 46 dBm.

Effects of Input Power Ratio of AlCr/Ti Target on the Microstructural and Mechanical Properties of AlTiCrN Coatings Synthesized by a High-Power Impulse Magnetron Sputtering Process

In this study, five AlTiCrN nitride coatings were deposited via high-power impulse magnetron sputtering (HiPIMS). The AlTiCrN coatings were synthesized with high contents of Al or Ti and a lower fraction of Cr, using Ti and Al70Cr30 targets with five different input power ratios. Electron probe microanalyzer results revealed that the increased rate of Ti contents in the coatings can be divided into two regions due to the difference of power densities for HiPIMS (&gt;0.5 kW/cm2) and modulated pulsed power (MPP) (&lt;0.5 kW/cm2). The deposition rate and thickness of the coatings depended on the sputtering yield of two metal targets under HiPIMS and MPP modes. The grain size of the coatings decreased from 60 to 40 nm as the input power ratios of the AlCr/Ti targets decreased due to their lower thickness values and lower Al content. Selected area electron diffraction patterns and X-ray diffraction results revealed that the TiN and AlTiN phases can be found in the coating containing higher Ti content, whereas the AlN, CrN, and AlCrN phases were observed in the coating with a higher Al concentration. Nevertheless, decreasing the concentration of Ti had a detrimental effect on the mechanical properties of AlTiCrN coatings, due to a promotion in grain size and the formation of AlN, which is softer than TiN. It is noticed that our results differed from those in previous reports, in which a grain refinement effect was observed due to increasing Al content. In this work, the effect of processing the parameters of the HiPIMS and MPP power systems on the grain size and the mechanical property of the coating was also discussed.

Multiejector CO2 cooling system with evaporative gascooler for a supermarket application in tropical regions

In the present study, the performance of a 33 kW multiejector trans-critical CO2 cooling system is experimentally evaluated for a supermarket application with/without internal heat exchanger and evaporative cooling. In order to enhance the overall performance of the system for tropical regions, the testing is carried out at high ambient temperature (up to 46 °C) with 5 cm, 10 cm and 15 cm cooling pad thickness arrangements. The experimental results clearly projects that the evaporative cooler capacity reaches a maximum of 10 cm pad thickness. However, a minor improvement is observed in terms of Coefficient of Performance and Power Input Ratio beyond 10 cm pad thickness. Maximum improvement in COP with internal heat exchanger and evaporative cooler is 11% and 40% respectively. On the other hand, a maximum reduction in the system Power Input Ratio with internal heat exchanger and evaporative cooler is 8.5% and 26% respectively. However, a minor enhancement in Coefficient of Performance and Power Input Ratio of 4% and 6% are observed respectively with 15 cm cooling pad thickness. Furthermore, a comparative analysis is carried out with the existing and present experimental study to project the compatibility of an evaporative condenser in the ejector based CO2 cooling system. From the study, it is evident that the evaporative cooling arrangement for the gascooler of the CO2 system is suggested as a potential solution to the supermarket application at a high ambient temperature context.

Steady‐state and transient hydrothermal analyses of single‐phase natural circulation loop using water‐based tri‐hybrid nanofluids

AbstractTransient and steady‐state characteristics of the natural circulation loop are studied using various water‐based tri‐hybrid (different nature and shaped nanoparticles) nanofluids. Effects of input power, loop inclination and loop aspect ratio on the mass flow rate, effectiveness, and entropy generation rate are studied. Results disclose that tri‐hybrid nanofluids reduce the oscillation and attain steady state faster than water. Effectiveness increases and entropy generation rate decreases by using tri‐hybrid nanofluids. Nanoparticle shape has found a significant impact. Al2O3 + Cu + CNT/water shows the best performance. The mass flow rate increases with input power, loop aspect ratio, whereas, reduces with loop inclination. Effectiveness decreases and then increases with input power, whereas increases with loop inclination and decreases with loop aspect ratio. Entropy generation upsurges with input power and loop inclination, whereas decreases with loop aspect ratio. Loop aspect ratio of 1.5 to 3 is found suitable for better performance.

Oxygen mass transfer coefficient and power consumption in a conventional stirred-tank bioreactor using different impeller in a non-Newtonian fluid: An experimental approach

In this study, we investigated the power consumption and volumetric mass transfer characteristics in an un-baffled stirred-tank bioreactor using a non-Newtonian fluid and different impellers. The impellers studied were a Rushton turbine impeller, a paddle impeller, a marine impeller, a segmented impeller and, a elephant ear impeller. Studies were performed over a wide range of agitation speeds (0–2000 rpm) and aeration (0.1–0.3 vvm). The effects of superficial gas velocity, impeller speed, power input, and liquid viscosity were studied as significant factors for KLa and power input estimation. The Rushton turbine impeller was found to be the most efficient in achieving higher KLa (0.015 min-1) even at lower agitation and aeration rates compared to other impellers. The trend of KLa was found to be similar for axial flow generating impellers. Correlations were derived for all the impellers at different superficial gas velocities (Vg) and gassed power per volume (Pg/V), and a correlation coefficient R2>0.99 was achieved in all the cases. The power drawn by the impellers was tested, and maximum power consumption was observed using the Ruston impeller (198.04W), followed by the paddle impeller (152.3W). However, under aerated conditions, the power consumption was lowered by 25–35% in all the cases. The power input ratio (Pg/Po) was found to be in the range of 0.35–0.61 for all the impellers studied. The power number (Np) was estimated and the results were found to be comparable with earlier studies. Thus, the present study gives more insight into the performance of different impellers and will be helpful in process development.

Microstructure Evolution and Mechanical Behavior of Mo–Si–N Films

The molybdenum silicon nitride (Mo–Si–N) films were deposited by a radio frequency (RF) magnetron reactive dual-gun co-sputtering technique with process control on input power and gas ratio. Composition variation, microstructure evolution, and related mechanical and tribological behavior of the Mo–Si–N coatings were investigated. The N2/(Ar + N2) flow ratios were controlled at 10/20 and 5/20 levels with the tuning of input power on the Si target at 0, 100, and 150 W. As the silicon contents increased from 0 to 33.7 at.%, the film microstructure evolved from a crystalline structure with Mo2N and MoN phases to an amorphous feature with the Si3N4 phase. The analysis of selected area electron diffraction patterns in TEM also indicated an amorphous feature of the Mo–Si–N films when Si content reached 20 at.% and beyond. The hardness and Young’s modulus changed from 16.5 to 26.9 and 208 to 273 GPa according to their microstructure features. The highest hardness and modulus were attributed to nanocrystalline Mo2N and MoN with Si solid-solution. The crystalline Mo–Si–N films showed a smooth tribological track and less wear failure was found. In contrast, the wear track with severe failures were observed for Mo–N and amorphous Mo–Si–N coatings due to their lower hardness. The ratios of H/E and H3/E2 were intensively discussed and correlated to the wear behavior of the Mo–Si–N coatings.

A Simulation Study on Large-Area Inductively Coupled Plasma for Uniformity Optimization

The characteristics of large-area inductively coupled plasma were investigated to optimize the uniformity using a self-consistent simulation based on a drift–diffusion approximation with anisotropic transport coefficients. As the aspect ratio increases, a tendency toward uniform plasma conditions of electron density on 450 mm wafer is reflected by an increase in the input power ratio of the outer coil. In the case of an aspect ratio of 0.29 (radius: 350 mm, height: 200 mm), the power distribution has a ratio of about 1.4:8.6, and the non-uniformity of the 450 mm wafer region is less than 1%. A lower aspect ratio is advantageous in terms of plasma uniformity. The plasma uniformity can be negatively affected by the electron density distribution changing to M-shape in the case of a lower aspect ratio of 0.3. When designing the chamber, the ratio of the surface area to the volume must be considered due to the differences in the plasma characteristics according to the radii and heights.

Performance Optimization of Diagonal Identity Matrix and Enhanced Double Weight Codes in Terms of Security for Short Haul Communication

Optical code division multiplexing is getting attention because it is an imminent multiple access technology which can cater ever increasing data traffic as well as multiple user access in optical networks. In this work, a zero cross correlation based diagonal identity matrix code is presented and it is compared with the enhanced double weight code to check the superior code in OCDMA system at data speed of 30 Gbps. Effect of some parameters of OCDMA system which prominently affects the security of the system and these are input power, linewidth and modulator extinction ratio. Optimization using single parameter optimization and multiple parameter optimizations has been done. In order to accomplish the work, optiwave optisystem software is used and extensive literature survey is done, issues encountered are carefully checked and to address the issues, proposed system is presented. Results are evaluated in terms of Q factor, bit error rate (BER) and signal to noise ratio. Novelty of proposed work is the search of optimal parameters of both the codes in terms of enhanced security such that eavesdropping at these optimal parameters will become tedious for unauthorized user.

Design and Experimental Verification of a 3-DOF Spherical Electromagnetic Brake for Haptic Interface

Electromagnetic brake is an efficient device that provides damping to stop the undesired motion of the manipulator. A spherical design of electromagnetic brake is presented with a simple and compact alternative for haptic application. The model exploits coulomb friction to generate fully controllable braking in 3-DOF rotational motion. For miniaturized applications, the design can provide significant torques while rejecting unwanted heat generated in the actuator. In this paper, the analytical models of magnetic force and friction moment are derived, and the brake design is optimized for maximizing the force to input power ratio. The spherical electromagnetic brake is applied for haptic interface and its performance is justified by the experimental results in the virtual reality environment.

Experimental studies on biogas combustion in a novel double layer inert Porous Radiant Burner

The objective of this study is to investigate the feasibility of raw biogas combustion in a state-of-the-art Sideway Faced Porous Radiant Burner (SFPRB). Combustion takes place in the circular double-layered SFPRB composed of Silicon Carbide (SiC) and Alumina (Al2O3) porous zones. The experimental investigations were performed in the input power range of 5–10 kW and within the stable equivalence ratio range of 0.75–0.97. A detailed study on the impact of these operational conditions on the thermal behaviour of SFPRB in terms of temperature distribution, radiation efficiency and emission characteristics are presented. Both gaseous and solid phase temperatures over the surface of the burner were found to increase with rise in input power. Heat distribution across the burner was found to be uniform for all the cases. Measured values of CO and NOx emissions were found to increase with increase in input power and equivalence ratio and reached maximum of 165 ppm and 8.2 ppm, respectively. The maximum radiation efficiency of 33% was found at 5 kW input power and 0.97 equivalence ratio. The overall assessment showed that the newly developed SFPRB was capable of providing efficient combustion of raw biogas in the lean fuel-air mixture range.

Co-amplification: An efficient spectral beam combination approach for high power, closely separated dual wavelength dye laser systems

Characteristics of an efficient spectral beam combination of two dye laser beams with wavelength difference of less than 10 nm are presented. Two dye laser oscillator beams were spatially and temporally combined with reduced losses before their co-amplification in a common power amplifier. Yellow and green beams of 9 kHz (pulse repetition rate) copper vapour laser (CVL) Master Oscillator Power Amplifier (MOPA) Chain were utilised to pump Rh 101 dye laser oscillators and DCM dye common amplifier respectively. The characteristics of green beam pumped DCM dye common amplifier were studied at various pump power and input power ratios. Combination losses for this configuration were 40% relative to individually amplified configuration. Input–output characteristics of the common amplifier were determined at various input power ratios. Composite dual wavelength dye laser beam having total power of 7.35W at 38.4 W pump power with extraction efficiency 16.5% was demonstrated.