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Articles 1 - 17 of 17
Full-Text Articles in Physical Sciences and Mathematics
Carbon Dioxide-Induced Corrosion Of Aisi 4140 Steel In Acidified Artificial Geothermal Brine, Anawati Anawati, Rayhan Izzat, Riene Kaelamanda Pragitta, Rafli Ihsan Hernandi
Carbon Dioxide-Induced Corrosion Of Aisi 4140 Steel In Acidified Artificial Geothermal Brine, Anawati Anawati, Rayhan Izzat, Riene Kaelamanda Pragitta, Rafli Ihsan Hernandi
Makara Journal of Science
Carbon dioxide (CO2)-induced corrosion often occurs in the structural materials of geothermal industry. The presence of CO2 influences the formation of various corrosion products. This research investigates the effect of dissolved CO2 in acidic brines on the corrosion behavior of AISI 4140 steel at atmospheric pressure. The brines were the standard brine, Ca-free brine, and high-salinity brine. The corrosion behavior was studied using electrochemical and immersion tests. A cyclic polarization test showed that the corrosion rate was higher in dissolved CO2 brine than in non-CO2 brine, and an immersion test demonstrated a similar result. …
Evaluation And Analysis Of New Method Of Measurement Of Target Scattering Matrix, Zhenyu Huang, Zhao Bo, Huanyao Dai, Liandong Wang, Xuequan Zhou
Evaluation And Analysis Of New Method Of Measurement Of Target Scattering Matrix, Zhenyu Huang, Zhao Bo, Huanyao Dai, Liandong Wang, Xuequan Zhou
Journal of System Simulation
Abstract: The basic theory of radar polarization signal processing is measurement of the target scattering matrix. The current algorithm of measurement of the target scattering matrix is gotten through orthogonal dual polarization channel in time-sharing or simultaneously, which demands orthogonal polarization measurement signals with complex coding. The measuring accuracy is higher. The complexity and the cost of the system are relatively higher. Scattering matrix can also be obtained by making use of the spatial polarization characteristics of the antenna to processing the radar echo without structure reformation of the radar. It only. needs to renewal measurement technology. The comparison and …
Perfect Circles: A Study Of The Scattering Regions Of Wolf Rayet Binary Stars, Stella Yoos, Jennifer Hoffman, Andrew Fullard
Perfect Circles: A Study Of The Scattering Regions Of Wolf Rayet Binary Stars, Stella Yoos, Jennifer Hoffman, Andrew Fullard
DU Undergraduate Research Journal Archive
Although we have been able to develop an understanding of many aspects of stellar evolution and formation, a few key gaps remain. One is the fate of massive binary star systems composed of Wolf-Rayet (WR) and O-type stars. In these WR + O binaries, the stellar winds surrounding these stars collide, creating a complex interaction region in which light from the stars scatters and becomes polarized. To study these scattering regions, I employ a technique that allows me to map the polarization of the light emitted from these stars and track its variation over the binary orbit. I found that …
Polarization Of Neural Codes, Katie Christensen, Hamid Kulosman
Polarization Of Neural Codes, Katie Christensen, Hamid Kulosman
Turkish Journal of Mathematics
The neural rings and ideals as an algebraic tool for analyzing the intrinsic structure of neural codes were introduced by C. Curto, V. Itskov, A. Veliz-Cuba, and N. Youngs in 2013. Since then they were investigated in several papers, including the 2017 paper by S. Güntürkün, J. Jeffries, and J. Sun, in which the notion of polarization of neural ideals was introduced. In our paper we extend their ideas by introducing the notions of polarization of motifs and neural codes. We show that the notions that we introduce have very nice properties which allow the studying of the intrinsic structure …
Methanol Masers In Star-Forming Regions, Nicolas Clarisse, Anuj P. Sarma
Methanol Masers In Star-Forming Regions, Nicolas Clarisse, Anuj P. Sarma
DePaul Discoveries
Methanol molecules in star-forming regions emit detectable microwave radiation. In particular, the rotational energy state transitions of methanol are responsible for two types of masers: Class I and Class II, found in the bipolar outflows and accretion disks of star-forming regions, respectively. Masers, being intense point-like sources in our sky, serve as an excellent source of information in further understanding the environment of high-mass star-forming regions due to their intense luminosities. High-mass star formation is still not entirely understood and remains an observational challenge. We have compiled a list of all the methanol maser transitions observed in the literature, in …
An Investigation Of The Synergistic Effect Between (1,3-Dioxolan-2-Ylmethyl)Triphenylphosphonium Bromide And Iodide Ion For The Corrosion Inhibition Of Zinc In Citric Acid, Saadawy M.
Journal of Electrochemistry
The effect of (1,3-Dioxolan-2-ylmethyl)-triphenylphosphonium bromide (DTPB) on the zinc corrosion in 0.5 mol·L-1 citric acid solution was investigated at 30 oC using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. An ecofriendly bath was used for acid cleaning of zinc, which has not been widely used in literatures. The results showed that DTPB could serve as an effective inhibitor for the zinc corrosion in a citric acid solution with the inhibition efficiency of 98.9% at the DTPB concentration of 3×10-3 mol·L-1. A synergistic effect between DTPB and potassium iodide (KI) enhanced the inhibition …
Relaxation Rate And Polarization Charge Density Model For Aln/Al$_{X}$Ga$_{1 - X}$N/Aln Heterostructures, Nagarajan Sivarajan, Reeba Korah, Mariya Kalavathy Ganamani
Relaxation Rate And Polarization Charge Density Model For Aln/Al$_{X}$Ga$_{1 - X}$N/Aln Heterostructures, Nagarajan Sivarajan, Reeba Korah, Mariya Kalavathy Ganamani
Turkish Journal of Electrical Engineering and Computer Sciences
This work describes the strain-relaxation--dependent carrier concentration ($n_{s})$ profile model using spontaneous and piezoelectric polarization for AlN/Al$_{x}$Ga$_{1 - x}$N/AlN HEMTs in all mole fraction ($x)$ interpolations. As $x$ varies, the Aluminum Gallium Nitride (AlGaN) channel shows strain relaxation with the Aluminum Nitride (AlN) barrier. The degree of relaxation is modeled from AlN to GaN regions in the channel. It shows that the AlN barrier and buffer relaxation and strain recovery occurs due to the gradual crystal quality degradation from barrier/buffer to the channel interface. These combination devices show less drain current degradation with temperature variation from 300 K to 573 …
Kinetics And Mechanism Of Acidic Electroless Ni-P Plating, Zhi-Hui Xie, Gang Yu
Kinetics And Mechanism Of Acidic Electroless Ni-P Plating, Zhi-Hui Xie, Gang Yu
Journal of Electrochemistry
Electrochemical behaviors of electroless nickel (EN) plating in three systems, namely, cathodic, anodic and complete bath solutions were investigated by polarization methods. The curves in the complete baths were not entirely consistent with those expected from a combination of the anodic and cathodic polarization curves, which implies that the anodic and cathodic reactions of the EN plating are interdependent. The effects of concentration of nickel ions, hypophosphite and pH on the polarization parameter and deposition rate in a complete bath were also discussed and compared by performing electrochemical and gravimetrical measurements. Based on these variations in the deposition potential and …
Insulation Condition Assessment Of Power Transformers Using Accelerated Ageing Tests, Mohammad Mirzaie, Ahmad Gholami, Hamid Reza Tayebi
Insulation Condition Assessment Of Power Transformers Using Accelerated Ageing Tests, Mohammad Mirzaie, Ahmad Gholami, Hamid Reza Tayebi
Turkish Journal of Electrical Engineering and Computer Sciences
Thermal stress due to losses and environment temperature causes degradation to paper/oil insulation systems in transformers, even at operating temperature. Experience indicates that thermal ageing of oil and paper in power transformers leads to the change of some insulation characteristics. In this paper, insulating papers immersed in oil have been acceleratory aged at 140, 150, and 160 °C under laboratory conditions. Some of the oil properties, such as water content, breakdown voltage, acidity, together with the aged insulating paper properties such as electric strength, dielectric dissipation factor and tensile strength were measured and analyzed. Also, insulation system conditions under thermal …
Electrochemical Behavior Of Dill Pipe In 31%(By Mass)Nacl Solution Based New Type Inhibitor, Fu-Guo Liu, Min Du, Qing-Zhang Wang
Electrochemical Behavior Of Dill Pipe In 31%(By Mass)Nacl Solution Based New Type Inhibitor, Fu-Guo Liu, Min Du, Qing-Zhang Wang
Journal of Electrochemistry
The inhibitive effect of compound inhibitor including emulsifier(P)、zinc sulfate、sodium polyphosphate、Glucose Gluconate was studied in 31% NaCl(bymass) solution.The inhibitory mechanism was analyzed by polarization curve and EIS.The results showed that the compound inhibitor was anodic-type inhibitor and its inhibitive effect on anodic and cathodal reaction was the most obvious at 200×10-6g·L-1.And the results of EIS revealed that the inhibition efficiency increased and the film formed on electrode surface was more and more compact with time.Inhibition mechanism was different with concentration of inhibitor.
Bimodality Revisited, Thomas R. Knapp
Bimodality Revisited, Thomas R. Knapp
Journal of Modern Applied Statistical Methods
Degree of bimodality is an important feature of a frequency distribution, because it could suggest heterogeneity, such as polarization or two underlying distributions combined into one. The literature contains several measures of bimodality. This article attempts to summarize most of those measures, with their attendant advantages and disadvantages.
Study On Composite Organic Inhibitor Of Zinc Electrode In Alkaline Solutions, Xue-Tao Bu, Guang-Chuan Liang, Cui Li
Study On Composite Organic Inhibitor Of Zinc Electrode In Alkaline Solutions, Xue-Tao Bu, Guang-Chuan Liang, Cui Li
Journal of Electrochemistry
The synergetic influence of sodium dodecyl benzene sulfonate(SDBS) with Tween-20(Tween) on zinc electrode was studied by polarization experiment,surface tension test,discharge test and SEM.It is found that the composite inhibitor ST has a much higher efficiency.The addition of Tween reduced the critical micell concentration of SDBS on zinc electrode remarkably and the distribution of adsorption became more homogeneous.ST inhibits corrosion of zinc electrode and improves discharge capacity of the whole battery.Through electrochemical morphological observation of anodic passivation behaviors of zinc electrode,the absorption of ST on electrode surface makes discharged production much smaller and keeps crude porous structure intact.Passivation of zinc electrode …
An Electrochemical Study Of Electroless Copper Plating Using Glyoxylic Acid As Reducing Agent, Li-Qiong Wu, Fang-Zu Yang
An Electrochemical Study Of Electroless Copper Plating Using Glyoxylic Acid As Reducing Agent, Li-Qiong Wu, Fang-Zu Yang
Journal of Electrochemistry
The electroless copper plating using glyoxylic acid as a reducing agent,Na_(2)EDTA as a chelating agent and K_(4)Fe(CN)_(6) and 2,2'-dipyridyl as additives was studied.The effect of chelating agent and addtives on the polangation behaviovs of copper reduction and glyoxylie acid oxidation were analyzed by linear sweep voltammetry.The results mainly demonstrated that the chelating agent hindered both the oxidation of glyoxylic acid and the reduction of copper complexing ions.It has revealed that K_(4)Fe(CN)_(6)and 2,2'-dipyridyl(with the content over than 20 mg/L)both played negative actions on the oxidation of glyoxylic acid.
An Electrochemical Study Of The Effects Of Chelating Agents And Additives On Electroless Copper Plating, Xin Gu, Zhou-Cheng Wang, Chang-Jian Lin
An Electrochemical Study Of The Effects Of Chelating Agents And Additives On Electroless Copper Plating, Xin Gu, Zhou-Cheng Wang, Chang-Jian Lin
Journal of Electrochemistry
In this study, ethylenediaminetetraacetic acid disodium salt (Na_2EDTA), triethanolamine(TEA), and 2,2′-dipyridine were adopted as chelating agents or additives in the electrolyte for electroless copper plating, and formaldehyde (HCHO) was as the reducting agent. Linear sweep voltammetry was applied to analyze the polarization behavior. The peak current of formaldehyde oxidation which increased by the addition of 2,2′-dipyridine is beneficial to formaldehyde oxidation in a specific range of concentration, While TEA decreased the peak current of formaldehyde oxidation. Two cathodic peaks due to copper(Ⅱ)reduction of TEA chelatation and copper(Ⅱ)reduction of EDTA chelatation were examined. EDTA increased the reduction peak current of Cu-EDTA …
Electrochemical Study On The Anodic Process Of Fes, Hong-Hui Xu
Electrochemical Study On The Anodic Process Of Fes, Hong-Hui Xu
Journal of Electrochemistry
Ferrous sulfide (FeS) was synthesized with spectrum-pure Fe and S at high-temperature, and its anodic behaviors in the solution of 0.5 mol·L~(-1) H_2SO_4 + 0.5 mol·L~(-1) K_2SO_4 was studied by using voltage sweep and step voltage techniques. The effects of acidity on the anodic polarization curves of FeS were investigated. The transfer coefficient β and exchange current density I_0 in the anodic electrode process, and the solid diffusion coefficient D_(Fe) of Fe~(2+) in FeS were measured. And also the activation energies of anodic reaction at different voltages was also determined.
Studies On Methods Of Fuel Cells Electrodes Preparation, Jun Gu, Sheng Sui, Guangqiang Li, Zhitong Sui
Studies On Methods Of Fuel Cells Electrodes Preparation, Jun Gu, Sheng Sui, Guangqiang Li, Zhitong Sui
Journal of Electrochemistry
In fuel cells,the structure of electrodes is an important factor which effect the cell performance.To improve the structure and the performance of electrodes,a new method of providing fuel cell electrodes is proposed in this paper.PTFE(polytetrafluoroethylene) and ethyne black was ground for about half an hour in a high_speed grinder,then the catalyst was added into the grinder and milled for an hour.This milled catalyst was transferred into a mixer followed by the addition of surface_active agent. After a suspension was formed,it was filtered under vacuum condition.Then a thin uniform filter_cake of the catalyst was formed,which was rolled together with a current_collecting …
Electrochemical Study Of The Corrosion Behavior Of Coalesced Copper And Sw-206 Stainless Steel In The Acetic-Acid Solution, Rongzong Hu, Changjian Lin, Jianguang Tan
Electrochemical Study Of The Corrosion Behavior Of Coalesced Copper And Sw-206 Stainless Steel In The Acetic-Acid Solution, Rongzong Hu, Changjian Lin, Jianguang Tan
Journal of Electrochemistry
In order to provide a theoretic and experimental consideration for the material selection and anit-corrosion in the petrochemical industries the corrosion behavior of coalesced copper and sw-206 stainless steel in the acetic acid solution was studied by electrochemical impedance spectroscopy and polarization techniques. The effects of the temperature,acetic acid concentration and solubilized oxygen in the acetic acid solution on the corrosion process of this two metals were analyzed. It was found that these effects obviously accelerate corrosion process for the coalesced copper,but no apparent influnce for the sw-206 stainless steel.In the the acetic acid solution,containing water and oxygen were beneficial …