Bias Power Research Articles

The Discriminant Analysis in the Evaluation of Cancers Diseases in Iraq

Cancer diseases are considered one of the most critical problems facing the world's countries, especially the State of Iraq. Many local and international reports indicated that the weapons used in wars and the accompanying nuclear and chemical radiation are among the most prominent reasons for the spread of cancerous diseases in Iraq. This study found that Gender has the highest discriminating power, whereas the Grade variable has the least discriminatory power. Similarly, Behavior has the highest discriminatory power, whereas the Government has the least biased power. It became clear that the third group (those with breast cancer) had the highest probability of the correct classification. The probability of correct classification reached 92%, followed by the second group with brain cancer, where the probability of correct classification was 64%. Finally, the first group with bladder cancer had the lowest probability of correct classification. We conclude that increasing the sample size has a significant impact on the correct classification of observations. The effects of these weapons were tremendously harmful to public health and the environment. Its effect persisted after many years, so three groups of cancer patients (bladder, brain, and breast cancer) were analyzed from 2012 to 2017 using a statistical method to analyze multivariate data. The results showed gender and the nature of the tumor (Behavior) have the highest discriminating power. The results were entirely satisfactory, as the discriminatory predictive capacity obtained a level of success of 72.2%.

MODIFICATION OF DIAMOND SURFACE DURING PHOTOLITHOGRAPHY, PLASMA-CHEMICAL CLEANING, AND MAGNETRON DEPOSITION

An influence of the conventional planar technology of the semiconductor surface treatment operations (photolithography, plasma-chemical surface cleaning in radio frequency low-pressure oxygen discharge, and thin metal films growth) on monocrystalline diamond surface topography and roughness is investigated. It is preliminary shown that photolithography without the plasma cleaning and magnetron deposition of an aluminum film do not induce any diamond surface changes which could be found by the optical profilometry, electron and optical microscopy. However, as a result of the lithography some organic contaminants can decrease the adhesion of the aluminum film and have to remove from the surface. Further, the influence of the above-listed surface treatment operations separately and in combinations on the synthetic diamond surface is investigated. It is found that an even short oxygen plasma cleaning during 5 min with a low bias power of 20 W leads to etching the grooves on the diamond surface The depth of the etching grooves varies by more than an order of magnitude in different experiments (0.3 - 19 nm), and by 10-20% within the same substrate under the influence of the poorly controlled external factors. Also, oxygen plasma treatment changes its secondary electron emission coefficient. Deposition of aluminum film after plasma cleaning does not induce noticeable changes in the diamond surface topography. The quality of diamond surface polishing (in “hard” of “soft” direction), the diamond’s type (IIa or IIb) as well as producing method (HPHT or homoepitaxial CVD) do not affect the result of grooves formation.

The Eternally Wounded Athlete: How Medical Professionals and Sports Injury Researchers Have Limited Female Athletes’ Sport Participation and Biased the Interpretation of Sports Injury Research

Female sports participation has long been diminished compared to male sports participation. This review contextualizes current findings in historical implicit gender bias. The transition from the recognition of the Female Athlete Triad Syndrome to the Relative Energy Deficiency in Sport Syndrome (RED-S Syndrome) to the newly proposed Male Athlete Triad Syndrome demonstrates the power of implicit gender bias on sports injury research efforts, clinical practices, and policy decisions. Similarly, anterior cruciate ligament (ACL) injuries have long been portrayed as a young female athlete injury, a perception which has affected the sports medicine world in a way that has resulted in both male and female athletes not fully benefitting from possible research and clinical advances. This review explores the history of female exclusion from sport and considers how modern sport and exercise medicine has, perhaps because of implicit gender biases, inadvertently contributed to that exclusion.

Plasma Nitrocarburizing of AISI 316L Austenitic Stainless Steel: a First Step for Treatment of Components with Complex Geometries

Abstract The surfaces of AISI 316L austenitic stainless steel components with complex shapes and geometries can be subjected to extreme loads with intensive wear stress resulting a short lifetime. Low temperature active screen plasma nitrocarburizing (ASPNC) can be applied to form a thin duplex layer known as expanded austenite, improving the hardness and wear resistance with acceptable corrosion resistance. However, ASPNC of shaped components and components with different aspect ratios may yield non-uniform expanded austenite layer and/or reproducibility problems limiting their applications for specific cases. In this study, first, ASPNC of AISI 316L treated at different temperatures was investigated using active screen made of carbon-fibre reinforced carbon (CFC) to determine a reliable treatment temperature without CrN precipitation. In addition, several non-uniformity effects related to geometry and shape of structured samples were investigated during ASPNC treatment at different biased conditions. It was shown that in case of structured samples, a weak bias power at the samples was an essential process parameter to guarantee the formation of thick and homogenous expanded austenite layer while in non-biased conditions, thin and inhomogeneous expanded austenite is formed.

Plasma Nitrocarburizing of AISI 316L Austenitic Stainless Steel: a First Step for Treatment of Components with Complex Geometries

Abstract The surfaces of AISI 316L austenitic stainless steel components with complex shapes and geometries can be subjected to extreme loads with intensive wear stress resulting a short lifetime. Low temperature active screen plasma nitrocarburizing (ASPNC) can be applied to form a thin duplex layer known as expanded austenite, improving the hardness and wear resistance with acceptable corrosion resistance. However, ASPNC of shaped components and components with different aspect ratios may yield non-uniform expanded austenite layer and/or reproducibility problems limiting their applications for specific cases. In this study, first, ASPNC of AISI 316L treated at different temperatures was investigated using active screen made of carbon-fibre reinforced carbon (CFC) to determine a reliable treatment temperature without CrN precipitation. In addition, several non-uniformity effects related to geometry and shape of structured samples were investigated during ASPNC treatment at different biased conditions. It was shown that in case of structured samples, a weak bias power at the samples was an essential process parameter to guarantee the formation of thick and homogenous expanded austenite layer while in non-biased conditions, thin and inhomogeneous expanded austenite is formed.

Optimal DCO-OFDM signal shaping with double-sided clipping in visible light communications.

Direct-current-biased optical orthogonal frequency-division multiplexing (DCO-OFDM) is widely used in high-speed visible light communication (VLC). Due to the limited dynamic range of light-emitting diode (LED) and the unipolarity for the intensity modulation (IM), double-sided clipping is inevitably imposed on the time-domain signal in VLC OFDM systems. Consequently, it calls for proper DCO-OFDM signal shaping by selecting an appropriate bias and time-domain signal power to reduce the clipping distortion and achieve a higher transmission rate. In this paper, we deep dive into the signal shaping design problem for double-sided clipping DCO-OFDM over both flat and dispersive channels. We derive the optimal bias for flat and dispersive channels, and explain its optimality from the perspectives of effective signal-to-noise ratio (SNR) and information theory. We then analytically characterize the optimal power for flat channels and propose a useful algorithm for dispersive channels enlightened by the optimal solution to the flat case. Furthermore, we uncover an inherent relationship between the considered double-sided clipping and the downside-clipping only DCO-OFDM regarding signal shaping optimization, and develop an in-depth understanding of the impact of top clipping based on the established connection. Practical simulations are provided to validate the superiority of our proposed signal shaping over the existing shaping schemes.

Depth profiling of surface damage in n-type GaN induced by inductively coupled plasma reactive ion etching using photo-electrochemical techniques

Depth profiling of the dry-etching damage in n-type GaN induced by inductively coupled plasma reactive ion etching was carried out by cyclical electrochemical impedance spectroscopy (EIS) measurements and damage-free photo-electrochemical (PEC) etching. The GaN samples were dry-etched under different etching bias power (Pbias) conditions, and PEC etchings were conducted in increments of 10 nm after EIS measurements. The damage depth was determined to be less than 50 nm for the sample corresponding to Pbias = 30 W and was less than 10 nm for the two-step etching sample corresponding to Pbias = 30 W + 5 W.

Off-line coupled simulation method for transformer performance assessment under DC bias condition

In this short communication, we intend to introduce an off-line coupled simulation method (OCM) framework for the DC biased power transformer performance assessing. The OCM combined with the electromagnetic transient (EMT) and finite element method (FEM) simulation, which can benefit from fast calculating excitng current and deail representing the transformer’s internal performance. It can be concluded from the numerical results of single-phase and three-phase transformers that it’s feasible to estimate the transformer performance under DC bias condition with the proposed OCM framework, and it’s quite promising in engineering application.

Effect of the RF bias on the plasma density in an argon inductively coupled plasma

Changing the RF bias is widely used to control the ion energy in inductively coupled plasma (ICP). Here, the plasma densities were measured using the floating harmonic method at various ICP powers and RF bias power frequencies. It is observed that there is an RF bias power (PB,min) that minimizes the plasma density. With increasing ICP power, PB,min is increased. When the frequency is changed from 12.5 MHz to 2 MHz, PB,min is decreased. To understand this phenomenon, the relative variation of the plasma density (δn) with the RF bias power is considered based on a power balance equation. PB,min is determined by δn, and δn changes based on the self-bias voltage caused by the RF bias power. Because the self-bias voltages change depending on the ICP power and frequency of the RF bias power, PB,min is shifted by altering the ICP power and the RF bias power frequency. The results are in good agreement with the experimental results.

The factor analytical approach in near unit root interactive effects panels

In a recent study, Bai (2013) proposes a new factor analytical (FA) method for estimation of stationary dynamic panel data models with fixed effects. Our interest in this method originates with the fact it does not require explicit demeaning of the data, a practice that is known to cause problems of bias and low power in near unit root panels. The purpose is to study the properties of FA when applied to such panels when the common component admits to a interactive effects representation, which is more general than fixed effects. It is shown that the estimator of the autoregressive parameter is consistent with a well centered asymptotic normal distribution, leading to unit root tests with maximal achievable power. In fact, FA is consistent and asymptotically normal regardless of whether the data are near unit root non-stationary or stationary. It is therefore very general and hence widely applicable.

Silver film etching using halogen gas plasma

Silver (Ag) film etching was studied with a focus on suppressing the surface roughness induced by Cl2 and CF4 plasmas. After Cl2 plasma etching, roughening of the Ag surface was observed. From in situ x-ray photoelectron spectroscopy and atomic force microscopy analyses using a plasma beam system, the Ag surface was roughened with AgCl formation after Cl2 plasma treatment before exposure to air. In capacitively coupled Cl2 plasma, it seemed that many voids were formed on the Ag surface at a high bias power and cathode temperature. This was considered to be characteristic of agglomeration. In contrast, severe surface roughness was not observed after CF4 plasma etching, even at a high bias power and cathode temperature. Secondary ion mass spectrometry analysis showed high chlorine accumulation near the Ag film surface after Cl2 plasma etching. Possible agglomeration of the Ag film during Cl2 plasma etching was volume expansion caused by chlorine accumulation assumed to enhance the compressive stress of the Ag film, and this resulted in increased boundary grooving and, finally, agglomeration. In contrast, fluorine accumulation was unlikely during CF4 plasma etching, resulting in less Ag film stress, which suppressed grain boundary grooving and agglomeration.

FEATURES OF SiO2 REACTIVE-ION ETCHING KINETICS IN CF4 + Ar + O2 AND C4F8 + Ar + O2 GAS MIXTURES

The effect of Ar/O2 mixing ratio on gas-phase characteristics and SiO2 etching kinetics in CF4 + Ar + O2 and C4F8 + Ar + O2 plasmas was studied under conditions of 13.56 MHz inductive RF discharge. The constant processing parameters were fraction of fluorocarbon component in a feed gas (50%) total gas pressure (6 mTorr), input power (700 W) and bias power (200 W). It was found that the full substitution of Ar for O2 in both gas systems results in non-monotonic (with a maximum at ~ 25% Ar + 25% O2) SiO2 etching rates as well as in monotonically increasing photoresist etching rate with higher absolute values for CF4-containing mixture. The steady-state densities of active species were determined using a combination of plasma diagnostics by Langmuir probes and 0-dimensional (global) plasma modeling. Corresponding results indicated that both gas systems are characterized by quite close parameters of electron and ion components while exhibit sufficient differences in the kinetics of neutral species, especially in the presence of O2. The latter produces opposite changes in F atom density as well as in effective probability of ion-assisted chemical reaction vs. Ar/O2 mixing ratio. Relationships between type of fluorocarbon component and heterogeneous process kinetics were analyzed through the set of gas-phase-related parameters (fluxes, flux-to-flux ratios) characterizing chemical etching pathways for SiO2 and formation/destruction balance for the fluorocarbon polymer film. It was suggested that the transition toward O2-rich plasma in the low-polymerizing CF4 + Ar + O2 plasma suppresses the effective probability for SiO2 + F reaction through decreasing efficiency for oxide bond breaking and desorption of etching products due to decreasing ion energy flux. Oppositely, an increase in O2 content in the high-polymerizing C4F8 + Ar + O2 mixture lifts up the effective reaction probability by decreasing fluorocarbon film thickness and providing better access of F atoms to the etched surface.

P‐84: The Effects of Bias Sputtering on the Properties of ZnO Nanorods Prepared from As‐deposited Thin films by Reducing Annealing Method

ZnO thin films were deposited radio frequency magnetron sputtering with a bias power. The highly‐orientated ZnO nanorods were prepared from ZnO films by an annealing process. The effects of bias on the properties of ZnO films and ZnO nanorods were investigated. The obtained ZnO films exhibits the comparable properties with different bias powers. ZnO nanorods were highly vertically grown. The compressive stress of ZnO nanorods showed a trend of increase with the bias power increasing. The obtained ZnO nanorods are expected for sensing application in displays.

Trilayer low-temperature-grown GaAs terahertz emitter and detector device with doped buffer

A low-temperature-grown GaAs (LTG-GaAs) terahertz (THz) photoconductive antenna device with layer structure consisting of doped buffer demonstrated enhanced emission intensity and detection sensitivity. As THz emitter, a 116% increase is exhibited by the LTG-GaAs with doped buffer relative to its undoped counterpart at 9 V bias and 0.8 mW pump power with spectral distribution extending to ∼3 THz. As a THz detector, a dynamic range of 55 dB is obtained at 0.5 THz, which is 5 dB higher than its undoped counterpart. The device proved effective as a THz emitter at low operating bias and pump power while its detection characteristics are acceptable even at low incident THz powers.

A new structure of a wide band bridge power limiter

In this work, new design and simulation of a microstrip power limiter based on Schottky diode is presented. The proposed circuit is a zero bias power limiter built by associating a transmission line in parallel to a four Schottky rectifier bridge circuit. The first circuit using a single stage rectifier is analyzed and simulated. To improve this single stage, a second and final limiter is designed with two stages rectifier. Simulation results for the final circuit show an ideal limiter behavior and good performance of limiting rate up to 20dB for a threshold input power varying from 5 dBm to 30 dBm. While insertion loss remains low at small signal.

Deep Reactive Ion Etching of Z-Cut Alpha Quartz for MEMS Resonant Devices Fabrication.

Quartz is widely used in microelectromechanical systems (MEMS). Especially, MEMS quartz resonators are applied to sensors and serve as sensitive elements. The capability of deep etching is a limitation for the application. Presented in this paper is a deep and high accuracy reactive ion etching method applied to a quartz resonator etching process with a Cr mask. In order to enhance the capability of deep etching and machining accuracy, three kinds of etching gas (C4F8/Ar, SF6/Ar and SF6/C4F8/Ar), bias power, inductively coupled plasma (ICP) power and chamber pressure were studied in an industrial reactive ion etching machine (GDE C200). Results indicated that the SF6/C4F8/Ar chemistry gas is the suitable and optimal choice. Experiment results indicate that Cr (chromium) mask can obtain a higher selectivity than aluminum and titanium mask. A “sandwich” structure composed of Al layer-Cr layer-Al layer-Cr layer was proposed. The Al (aluminum) film can play the role of releasing stress and protecting gold electrodes, which can enhance the thickness of metal mask. An optimized process using SF6/C4F8/Ar plasmas showed the quartz etching rate of 450 nm/min. Meanwhile, a microchannel with a depth of 75.4 µm is fabricated, and a nearly vertical sidewall profile, smooth surface is achieved.

Dry Etching Characteristics of 16-nm Amorphous Carbon Layer in a Dual-Frequency Plasma Etcher

The etching characteristics of a patterned amorphous carbon layer (ACL) in a magnetized inductively coupled plasma (MICP) etcher were investigated. The etch rate and etched profile dependences on the source power, the neutral gas pressure and the dual bias power ratio were investigated. We measured the ion energy distribution (IED), the ion flux, plasma density and electron temperature using an ion energy analyzer (IEA) and a dual Langmuir probe (DLP). The etching rate and the anisotropy of ACL relative to change in the dual bias power ratio of two bias power generators operating at frequencies of 2 and 13.56 MHz were observed. The bowed profile could be improved by appropriate adjustment of the dual bias power ratio.

A Synthetic Likelihood Solution to the Silent Synapse Estimation Problem

Functional features of synaptic populations are typically inferred from random electrophysiological sampling of small subsets of synapses. Are these samples unbiased? Here, we develop a biophysically constrained statistical framework to address this question and apply it to assess the performance of a widely used method based on a failure-rate analysis to quantify the occurrence of silent (AMPAR-lacking) synapses. We simulate this method in silico and find that it is characterized by strong and systematic biases, poor reliability, and weak statistical power. Key conclusions are validated by whole-cell recordings from hippocampal neurons. To address these shortcomings, we develop a simulator of the experimental protocol and use it to compute a synthetic likelihood. By maximizing the likelihood, we infer silent synapse fraction with no bias, low variance, and superior statistical power over alternatives. Together, this generalizable approach highlights how a simulator of experimental methodologies can substantially improve the estimation of physiological properties.

Plasma Parameters and Silicon Etching Kinetics in C4F8 + O2 + Ar Gas Mixture: Effect of Component Mixing Ratios

In this work, we investigated the possibidlxlity to control both gas-phase chemistry and silicon etching kinetics in C4F8 + O2 + Ar inductively coupled plasma by changes in O2/Ar, C4F8/O2 and C4F8/Ar mixing ratios at the constant fraction of the rest component (50%), gas pressure (10 mTorr), input power (700 W) and bias power (200 W). The combination of plasma diagnostics and modeling tools allowed one: (a) to compare the effects of gas mixing ratios on both steady-state plasma parameters and densities of active species; (b) to figure out key processes which determine the fluorine atom formation/decay balance in each gas system; and (c) to analyze the differences in Si etching kinetics in terms of process-condition-dependent effective reaction probability. It was shown that the maximum changes in gas-phase chemistry take place in O2-rich plasmas due to CFx + O/O(1D) → CFx−1O + F, CFxO + e → CFx−1O + F + e and CFO + O/O(1D) → CO2 + F stepwise dissociation pathways. It was suggested also that the effective probability for Si + xF → SiFx reaction may be controlled by either fluorocarbon film thickness (in C4F8—rich plasmas) or O atom flux (in Ar and O2—rich plasmas) through the balance of adsorption sites on the etched surface.

A Novel Oxygen-Based Digital Etching Technique for p-GaN/AlGaN Structures without Etch-Stop Layers**Supported by the Guangdong Science and Technology Department (Grant Nos. 2019B010128001 and 2019B010142001), the Shenzhen Municipal Council of Science and Innovation (Grant Nos. JCYJ20180305180619573 and JCYJ20170412153356899), and the National Natural Science Foundation of China (Grant No. 61704004).

A novel O2 plasma-based digital etching technology for p-GaN/AlGaN structures without any etch-stop layer was investigated using an inductively coupled plasma (ICP) etcher, with 100 W ICP power and 40 W rf bias power. Under 40 sccm O2 flow and 3 min oxidation time, the p-GaN etch depth was 3.62 nm per circle. The surface roughness improved from 0.499 to 0.452 nm after digital etching, meaning that no observable damages were caused by this process. Compared to the dry etch only methods with Cl2/Ar/O2 or BCl3/SF6 plasma, this technique smoothed the surface and could efficiently control the etch depth due to its self-limiting characteristic. Furthermore, compared to other digital etching processes with an etch-stop layer, this approach was performed using ICP etcher and less demanding on the epitaxial growth. It was proved to be effective in precisely controlling p-GaN etch depth and surface damages required for high performance p-GaN gate high electron mobility transistors.