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Articles 1891 - 1920 of 8897

Full-Text Articles in Physical Sciences and Mathematics

Adaptive Fast Sliding Neural Control For Robot Manipulator, Bariş Özyer Jan 2020

Adaptive Fast Sliding Neural Control For Robot Manipulator, Bariş Özyer

Turkish Journal of Electrical Engineering and Computer Sciences

Robotic manipulators are open to external disturbances and actuation failures during performing a task such as trajectory tracking. In this paper, we present a modifed controller consisting of a global fast sliding surface combined with an adaptive neural network which is called adaptive fast sliding neural control (AFSNC) for a robotic manipulator to precise stable trajectory tracking performance under the external disturbances. The adaptive term is employedtoreduce uncertainties due to unmodeled dynamics. Trackingerror asymptoticallyconvergesto zero according to the Lyapunov stability theorem. Numerical examples have been carried on a planar two-links manipulator to verify the control approach efficiency. The experimental results …


Design And Application Of Spwm Based 21-Level Hybrid Inverter For Induction Motor Drive, Sheikh Tanzim Meraj, Kamrul Hasan, Ammar Masaoud Jan 2020

Design And Application Of Spwm Based 21-Level Hybrid Inverter For Induction Motor Drive, Sheikh Tanzim Meraj, Kamrul Hasan, Ammar Masaoud

Turkish Journal of Electrical Engineering and Computer Sciences

Thispaperpresentstheapplicationofanewlydeveloped21-levelhybridmultilevelinverter. Ahighfrequency modulation technique known as sinusoidal pulse width modulation (SPWM) is applied to the hybrid inverter. This modulation methodology operates the switching sequences of the multilevel inverter to produce the desired 21-level output voltage. To validate the proper application of this inverter, it is further utilized to maintain the speed of a single phase induction motor. The velocity control of the motor is established on the principle of V/f control technique. The speed control strategy along with the compatibility of the SPWM modulation technique were verified by means of simulation and experimental results.


Analysis Of Biometric Data Using Watermarking Techniques, Foday Jorh, Bariş Özyer, Claude Fachkha Jan 2020

Analysis Of Biometric Data Using Watermarking Techniques, Foday Jorh, Bariş Özyer, Claude Fachkha

Turkish Journal of Electrical Engineering and Computer Sciences

This paper evaluates and analyses the discrete wavelet transform (DWT) frequency bands for embedding and extracting of the biometric data using DWT single level and multilevel watermarking approach with and without the use of alpha blending approach. In addition, singular value decomposition (SVD) combined with DWT is used to embed and extract the watermark image. The performance of compression and decompression approaches has been analyzed to examine the robustness and to check whether the compression function does destroy the integrity of the watermarked image. We investigate the proposed approach to understand how robust the watermarked on different sub-band is against …


An Intelligent Diagnostic Method Based On Optimizing B-Cell Pool Clonal Selection Classification Algorithm, Chao Lan, Hongli Zhang, Xin Sun, Zhongyuan Ren Jan 2020

An Intelligent Diagnostic Method Based On Optimizing B-Cell Pool Clonal Selection Classification Algorithm, Chao Lan, Hongli Zhang, Xin Sun, Zhongyuan Ren

Turkish Journal of Electrical Engineering and Computer Sciences

The trend of intellectualization and complication of mechanical equipment makes the demand for intelligent diagnostic methods more and more intense in industry. In view of the difficulty of obtaining mechanical fault samples and the requirement of clear and reliable diagnosis results, intelligent diagnosis methods need to adapt to the learning of small samples and have the interpretability of white box model. In this paper, inspired by biological immunity, an intelligent fault diagnosis method was proposed-optimizing b-cell pool clonal selection classification algorithm (OBPCSCA). The OBPCSCA provides a method to construct unique B-cell pools corresponding to specific antigen pools, and uses greedy …


Automated Labeling Of Terms In Medical Reports In Serbian, Aldina Avdic, Ulfeta Marovac, Dragan Jankovic Jan 2020

Automated Labeling Of Terms In Medical Reports In Serbian, Aldina Avdic, Ulfeta Marovac, Dragan Jankovic

Turkish Journal of Electrical Engineering and Computer Sciences

Nowadays, many electronic health reports (EHRs) are stored daily. They consist of the structured part and of an unstructured section written in natural language. Due to the limited time for medical examination, EHRs are short reports which often contain errors and abbreviations. Therefore it is a challenge to process an EHR and extract knowledge from this part of the text for different purposes. This paper compares the results of three proposed methods for automatic labeling of medical terms in unstructured parts of EHRs. All words are categorized as words within the medical domain (symptoms, diagnoses, therapies, anatomy, specialties etc.) and …


Quantum Key Distribution Over Free Space Optic (Fso) Channel Using Higher Order Gaussian Beam Spatial Modes, Muhammad Kamran, Dr. Muhammad Mubashir Khan, Tahir Malik, Asad Arfeen Jan 2020

Quantum Key Distribution Over Free Space Optic (Fso) Channel Using Higher Order Gaussian Beam Spatial Modes, Muhammad Kamran, Dr. Muhammad Mubashir Khan, Tahir Malik, Asad Arfeen

Turkish Journal of Electrical Engineering and Computer Sciences

Quantum key distribution(QKD) has emerged as a secure solution of secret key distribution utilizing the well established theories of modern physics. Since its introduction in 1984, many interesting and innovative ideas have been proposed for QKD in order to improve the security and efficiency of the scheme keeping in view of its applications and practicalimplementation. High error rate QKD scheme for long distance communication-theso-called KMB09 protocol is one such scheme which was designed to achieve longer communication distance in QKD, without compromising its security,by allowing the utilisation of higher dimensional photon states which is not possible with standard BB84 scheme. …


Improving Coverage Method Of Autonomous Drones For Environmental Monitoring, Ömür Yildirim, Revna Acar Vural, Klaus Diepold Jan 2020

Improving Coverage Method Of Autonomous Drones For Environmental Monitoring, Ömür Yildirim, Revna Acar Vural, Klaus Diepold

Turkish Journal of Electrical Engineering and Computer Sciences

With the rapid developments of unmanned aerial vehicles (UAVs), usage of UAVs is increasing to bring autonomy for complicated processes such as environmental monitoring. Because of the complexity of the problem, environmental monitoring tasks are highly demanding in terms of time and resources. To reduce expensive costs of operations, improvements on autonomous observation capabilities has a key role. In this work, we offer coverage improvements for our autonomous environmental monitoring system. We compared different path planning approaches to find out the optimum path planning solution. Simulation results showed that required task execution time and required resources are decreased by usage …


A Regular Expression Generator Based On Css Selectors For Efficient Extraction From Html Pages, Erdi̇nç Uzun Jan 2020

A Regular Expression Generator Based On Css Selectors For Efficient Extraction From Html Pages, Erdi̇nç Uzun

Turkish Journal of Electrical Engineering and Computer Sciences

Cascading style sheets (CSS) selectors are patterns used to select HTML elements. They are often preferred in web data extraction because they are easy to prepare and have short expressions. In order to be able to extract data from web pages by using these patterns, a document object model (DOM) tree is constructed by an HTML parser for a webpage. The construction process of this tree and the extraction process using this tree increase time and memory costs depending on the number of HTML elements and their hierarchies. For reducing these costs, regular expressions can be considered as a solution. …


Binary Multicriteria Collaborative Filtering, Emre Yalçin, Alper Bi̇lge Jan 2020

Binary Multicriteria Collaborative Filtering, Emre Yalçin, Alper Bi̇lge

Turkish Journal of Electrical Engineering and Computer Sciences

Collaborative filtering is specialized in suggesting appropriate products and services to the users concerning personal characteristics and past preferences without requiring any effort of users. It might be more efficient to collect preferences of users based on multiple subcriteria of products and services. For this purpose, researchers propose multicriteria recommender systems that are convenient for more accurate and useful evaluation of items. Insuchsystems, it might be preferable tocollect binary ratings instead of numerical ones due to the large number of subcriteria. However, there is a gap in the literature to satisfy a binary preferences-based multicriteria recommender system. In this study, …


A New Grid Partitioning Technology For Location Privacy Protection, Yue Sun, Lei Zhang, Jing Li, Zhen Zhang Jan 2020

A New Grid Partitioning Technology For Location Privacy Protection, Yue Sun, Lei Zhang, Jing Li, Zhen Zhang

Turkish Journal of Electrical Engineering and Computer Sciences

Nowadays, the location-based service (LBS) has become an essential part of convenient service in people's daily life. However, the untrusted LBS servers can store lots of information about the user, such as the user's identity, location, and destination. Then the information can be used as background knowledge and combined with the query frequency of the user to launch the inference attack to obtain user's privacy. In most of the existing schemes, the author considers the algorithm of virtual location selection from the historical location of the user. However, the LBS server can infer the user's location information on the historical …


Multi-Parameter Optical Metrology: Quantum And Classical, Walker Larson Jan 2020

Multi-Parameter Optical Metrology: Quantum And Classical, Walker Larson

Electronic Theses and Dissertations, 2020-2023

The insights offered by quantum mechanics to the field of optical metrology are many-fold, with non-classical states of light themselves used to make sensors that surpass the sensitivity of sensors using classical states of light. Unfortunately, this advantage, referred to often as "super-sensitivity" is notoriously fragile, and even the slightest experimental imperfections may greatly reduce the efficacy of the non-classical sensors, sometimes completely obviating their advantage. In my thesis I have shown that the performance of an otherwise ideal two-photon interferometer, which exploits entanglement between photons to make super-sensitive measurements of phase, is crippled by the slightest introduction of decoherence …


Fluorescence Microscopy With Tailored Illumination Light, Jialei Tang Jan 2020

Fluorescence Microscopy With Tailored Illumination Light, Jialei Tang

Electronic Theses and Dissertations, 2020-2023

Fluorescence microscopy has long been a valuable tool for biological and medical imaging. Control of optical parameters such as the amplitude, phase, polarization and propagation angle of light gives fluorescence imaging great capabilities ranging from single molecule imaging to long-term observation of living organisms. While numerous fluorescence imaging techniques have been developed over the past decades, there is always an inevitable tradeoff among the spatial resolution, imaging speed, contrast, photodamage and the total cost when it comes to choose the appropriate microscope. A main goal of my dissertation research is to develop state-of-the-art microscope systems that exhibit unprecedented performance in …


Attosecond Transient Absorption Spectroscopy In The Water Window, Andrew Chew Jan 2020

Attosecond Transient Absorption Spectroscopy In The Water Window, Andrew Chew

Electronic Theses and Dissertations, 2020-2023

The push to study the atomic and molecular dynamics at ever smaller time scales has been the main driving force for developing laser systems with ever shorter pulse durations. Thus far, picosecond lasers and femtosecond lasers have been used with great success in femtochemistry to study molecular dynamics such as molecular rotation and vibration, which all occur in the tens to hundreds of femtosecond. To study electron dynamics however, which are on the order of attoseconds, one needs attosecond laser sources to be able to have the time resolution required to probe ultrafast electron dynamics such as AC Stark shifts, …


High Performance Micro-Scale Light Emitting Diode Display, Fangwang Gou Jan 2020

High Performance Micro-Scale Light Emitting Diode Display, Fangwang Gou

Electronic Theses and Dissertations, 2020-2023

Micro-scale light emitting diode (micro-LED) is a potentially disruptive display technology because of its outstanding features such as high dynamic range, good sunlight readability, long lifetime, low power consumption, and wide color gamut. To achieve full-color displays, three approaches are commonly used: 1) to assemble individual RGB micro-LED pixels from semiconductor wafers to the same driving backplane through pick-and-place approach, which is referred to as mass transfer process; 2) to utilize monochromatic blue micro-LED with a color conversion film to obtain a white source first, and then employ color filters to form RGB pixels, and 3) to use blue or …


Heterogeneous Integrated Photonics For Nonlinear Frequency Conversion And Polarization Diversity, Tracy Sjaardema Jan 2020

Heterogeneous Integrated Photonics For Nonlinear Frequency Conversion And Polarization Diversity, Tracy Sjaardema

Electronic Theses and Dissertations, 2020-2023

Silicon has proven to be one of the materials of choice for many integrated photonic applications. However, silicon photonics is limited by certain material shortcomings. Two shortcomings addressed in this work are zero second-order optical nonlinearity, and the lack of methods available to achieve broadband polarization diversity. Heterogeneous integrated solutions for these shortcomings of silicon photonics are presented in this work. First, nonlinear frequency conversion is demonstrated with thin-film lithium niobate on silicon substrates. The method for reaching the highest-achieved second-harmonic generation conversion efficiency, using active monitoring during periodic poling, is discussed. Additionally, a cascaded approach for generating higher-order harmonics …


Observation Of Reduced Thermal Conductivity In A Metal-Organic Framework Due To The Presence Of Adsorbates, Hasan Babaei, Mallory E. Decoster, Minyoung Jeong, Zeinab M. Hassan, Timur Islamoglu, Helmut Baumgart, Alan J.H. Mcgaughey, Engelbert Redel, Omar K. Farha, Patrick E. Hopkins, Jonathan A. Malen, Christopher E. Wilmer Jan 2020

Observation Of Reduced Thermal Conductivity In A Metal-Organic Framework Due To The Presence Of Adsorbates, Hasan Babaei, Mallory E. Decoster, Minyoung Jeong, Zeinab M. Hassan, Timur Islamoglu, Helmut Baumgart, Alan J.H. Mcgaughey, Engelbert Redel, Omar K. Farha, Patrick E. Hopkins, Jonathan A. Malen, Christopher E. Wilmer

Electrical & Computer Engineering Faculty Publications

Whether the presence of adsorbates increases or decreases thermal conductivity in metal-organic frameworks (MOFs) has been an open question. Here we report observations of thermal transport in the metal-organic framework HKUST-1 in the presence of various liquid adsorbates: water, methanol, and ethanol. Experimental thermoreflectance measurements were performed on single crystals and thin films, and theoretical predictions were made using molecular dynamics simulations. We find that the thermal conductivity of HKUST-1 decreases by 40 – 80% depending on the adsorbate, a result that cannot be explained by effective medium approximations. Our findings demonstrate that adsorbates introduce additional phonon scattering in HKUST-1, …


Semi-Supervised Adversarial Domain Adaptation For Seagrass Detection Using Multispectral Images In Coastal Areas, Kazi Aminul Islam, Victoria Hill, Blake Schaeffer, Richard Zimmerman, Jiang Li Jan 2020

Semi-Supervised Adversarial Domain Adaptation For Seagrass Detection Using Multispectral Images In Coastal Areas, Kazi Aminul Islam, Victoria Hill, Blake Schaeffer, Richard Zimmerman, Jiang Li

Electrical & Computer Engineering Faculty Publications

Seagrass form the basis for critically important marine ecosystems. Previously, we implemented a deep convolutional neural network (CNN) model to detect seagrass in multispectral satellite images of three coastal habitats in northern Florida. However, a deep CNN model trained at one location usually does not generalize to other locations due to data distribution shifts. In this paper, we developed a semi-supervised domain adaptation method to generalize a trained deep CNN model to other locations for seagrass detection. First, we utilized a generative adversarial network loss to align marginal data distribution between source domain and target domain using unlabeled data from …


Priority Based Routing And Link Scheduling For Cognitive Radio Networks, Peng Jiang, Mitchell Zhou, Song Wen Jan 2020

Priority Based Routing And Link Scheduling For Cognitive Radio Networks, Peng Jiang, Mitchell Zhou, Song Wen

Electrical & Computer Engineering Faculty Publications

To address the challenges caused by the time-varying rate requirement for multimedia communication sessions, we propose a Priority Based Routing and link Scheduling (PBRS) scheme for multi-hop cognitive radio networks. The objective is to minimize disruption to communication sessions due to channel switching as well as to minimize network resource consumption for multimedia applications based on a prioritized routing and resource allocation scheme. PBRS includes a priority based optimization formulation and an efficient algorithm to solve the problem. The main idea is to allocate the available resource to different types of services with their Quality of Experience (QoE) expectation as …


Speech Mode Classification Using The Fusion Of Cnns And Lstm Networks, Pratyusha Chowdary Vakkantula Jan 2020

Speech Mode Classification Using The Fusion Of Cnns And Lstm Networks, Pratyusha Chowdary Vakkantula

Graduate Theses, Dissertations, and Problem Reports

Speech mode classification is an area that has not been as widely explored in the field of sound classification as others such as environmental sounds, music genre, and speaker identification. But what is speech mode? While mode is defined as the way or the manner in which something occurs or is expressed or done, speech mode is defined as the style in which the speech is delivered by a person.

There are some reports on speech mode classification using conventional methods, such as whispering and talking using a normal phonetic sound. However, to the best of our knowledge, deep learning-based …


Investigation Of Phonon Polaritons In An Hbn Gan Heterostructure, Catherine G. O'Hearn Jan 2020

Investigation Of Phonon Polaritons In An Hbn Gan Heterostructure, Catherine G. O'Hearn

Graduate Theses, Dissertations, and Problem Reports

There have been many great advances in the generation and manipulation of optics in the visible and near infrared (IR) range over the past decade. This is largely due to plasmonic enhancement, which has led to new technology in biosensing and molecule detection, solid-state lighting, and solar energy harvesting. The field of plasmonics uses quanta of plasma oscillations, plasmons, formed from the interaction between electromagnetic radiation and free electrons to enhance optical near field magnitudes. However, there is still a large region of the electromagnetic spectrum, covering the mid-infrared (MIR) and terahertz (THz) regions, ranging from 3 μm to 1 …


System Efficient Esd Design Concept For Soft Failures, Giorgi Maghlakelidze Jan 2020

System Efficient Esd Design Concept For Soft Failures, Giorgi Maghlakelidze

Doctoral Dissertations

"This research covers the topic of developing a systematic methodology of studying electrostatic discharge (ESD)-induced soft failures. ESD-induced soft failures (SF) are non-destructive disruptions of the functionality of an electronic system. The soft failure robustness of a USB3 Gen 1 interface is investigated, modeled, and improved. The injection is performed directly using transmission line pulser (TLP) with varying: pulse width, amplitude, polarity. Characterization provides data for failure thresholds and a SPICE circuit model that describes the transient voltage and current at the victim. Using the injected current, the likelihood of a SF is predicted. ESD protection by transient voltage suppressor …


Synthesis Of Graphene Using Plasma Etching And Atmospheric Pressure Annealing: Process And Sensor Development, Andrew Robert Graves Jan 2020

Synthesis Of Graphene Using Plasma Etching And Atmospheric Pressure Annealing: Process And Sensor Development, Andrew Robert Graves

Graduate Theses, Dissertations, and Problem Reports

Having been theorized in 1947, it was not until 2004 that graphene was first isolated. In the years since its isolation, graphene has been the subject of intense, world-wide study due to its incredibly diverse array of useful properties. Even though many billions of dollars have been spent on its development, graphene has yet to break out of the laboratory and penetrate mainstream industrial applications markets. This is because graphene faces a ‘grand challenge.’ Simply put, there is currently no method of manufacturing high-quality graphene on the industrial scale. This grand challenge looms particularly large for electronic applications where the …


Bio-Inspired Learning And Hardware Acceleration With Emerging Memories, Shruti R. Kulkarni Dec 2019

Bio-Inspired Learning And Hardware Acceleration With Emerging Memories, Shruti R. Kulkarni

Dissertations

Machine Learning has permeated many aspects of engineering, ranging from the Internet of Things (IoT) applications to big data analytics. While computing resources available to implement these algorithms have become more powerful, both in terms of the complexity of problems that can be solved and the overall computing speed, the huge energy costs involved remains a significant challenge. The human brain, which has evolved over millions of years, is widely accepted as the most efficient control and cognitive processing platform. Neuro-biological studies have established that information processing in the human brain relies on impulse like signals emitted by neurons called …


Study On Electro-Sorption Of Heavy Metals And Sulfamethoxazole On Activated Carbon Fibers, Wen-Jun Zhao, Bing-Xin Jia, Ya-Nan Zhang, Jiu-Nian Guan, Jiao Qu, Ying Lu Dec 2019

Study On Electro-Sorption Of Heavy Metals And Sulfamethoxazole On Activated Carbon Fibers, Wen-Jun Zhao, Bing-Xin Jia, Ya-Nan Zhang, Jiu-Nian Guan, Jiao Qu, Ying Lu

Journal of Electrochemistry

To study the optimal removal condition, adsorption mechanism and comparative analysis of the three typical cationic pollutants, i.e., Zn(II), anionic pollutant Cr(VI) and molecular pollutant sulfamethoxazole (SMX), using self-made upflowed electro-sorption device for adsorptions of above three pollutants by modified activated carbon fiber were researched. The activated carbon fiber (ACF) was modified by hydrochloric acid. The ACF morphology and structure before and after modification were characterized by SEM, BET and FTIR. The characterization results show that the modified ACF had fewer surface impurities than the modified surface and the gully is more obvious, the specific surface area was increased by …


Transient Electrochemical Surface-Enhanced Raman Spectroscopic Study In Electrochemical Reduction Of P-Nitrothiophenol, Yun Ling, Jing Tang, Guo-Kun Liu, Cheng Zong Dec 2019

Transient Electrochemical Surface-Enhanced Raman Spectroscopic Study In Electrochemical Reduction Of P-Nitrothiophenol, Yun Ling, Jing Tang, Guo-Kun Liu, Cheng Zong

Journal of Electrochemistry

P-nitrothiophenol (PNTP) is one of the most common probe molecules studied by surface-enhanced Raman spectroscopy (SERS). The research in electrochemical reduction behavior of PNTP will help understanding the mechanism for the nitrobenzene reduction. In this paper, we used transient electrochemical surface-enhanced Raman spectroscopy (TEC-SERS) to study the SERS of PNTP with cyclic voltammetry and chronoamperometry on gold electrodes. The results show that the TEC-SERS provide a time resolution that equals the transient electrochemical methods, and we concluded that the reaction was so quick that we did not observe the spectral information of intermediate species described in the literatures with a …


Electrochemical Sensor Based On Magnetic Electrode Modified With Magnetic Molecularly Imprinted Nanoparticles Immobilized Hemoglobin For Determination Of Hydrogen Peroxide, Yang Yuan, Jia-Xin Wang, Yu-Hua Cao Dec 2019

Electrochemical Sensor Based On Magnetic Electrode Modified With Magnetic Molecularly Imprinted Nanoparticles Immobilized Hemoglobin For Determination Of Hydrogen Peroxide, Yang Yuan, Jia-Xin Wang, Yu-Hua Cao

Journal of Electrochemistry

In this work, the surface-imprinted technique was used to prepare magnetic hemoglobin (Hb) imprinted nanoparticles, using Fe3O4@SiO2 NPs as the carrier, Hb as the template molecule, and tetraethyl orthosilicate (TEOS) as the imprinted polymer monomer. The nanoparticles had a core-shell structure, with magnetic Fe3O4 NPs as the core and Hb imprinted polymers as the shell. Therefore, Hb could be concentrated and fixed on the surface of the magnetic imprinted nanoparticles (MMIPs NPs). Furthermore, MMIPs NPs were immobilized with chitosan (CS) on the surface of a magnetic electrode to constitute Hb enzyme-like biosensor …


Zif-67-Derived Ag/Co-Embedded N-Enriched Mesoporous Carbon For Oxygen Reduction Reaction, Zheng-Ling Di, Jing Zhu, Lei Dai, Wei Meng, Yue-Hua Li, Zhang-Xing He, Ling Wang Dec 2019

Zif-67-Derived Ag/Co-Embedded N-Enriched Mesoporous Carbon For Oxygen Reduction Reaction, Zheng-Ling Di, Jing Zhu, Lei Dai, Wei Meng, Yue-Hua Li, Zhang-Xing He, Ling Wang

Journal of Electrochemistry

Nitrogen-doped porous carbon materials are considered as one of the most promising catalysts for oxygen reduction reaction (ORR). Herein, in order to further improve the activity of the nitrogen-doped porous carbon, Ag/Co bimetal is embedded into nitrogendoped porous carbon to form Ag/Co-embedded nitrogen-doped porous carbon material (AgCo@NC). The AgCo@NC was derived by the wet impregnation of Ag+ into ZIF-67 precursor, followed by chemical reduction and a subsequent pyrolysis process under Ar atmosphere at different temperatures (500 ℃, 600 ℃, 700 ℃). The morphologic characterization shows that the Ag/Co nanoparticles were successfully embedded in the mesoporous carbon framework with abundant nitrogen …


Ionic Liquid Assisted Synthesis Of Porous Carbons From Rice Husk For Supercapacitors, Han-Fang Zhang, Feng Wei, Jian Sun, Meng-Ying Jing, Xiao-Jun He Dec 2019

Ionic Liquid Assisted Synthesis Of Porous Carbons From Rice Husk For Supercapacitors, Han-Fang Zhang, Feng Wei, Jian Sun, Meng-Ying Jing, Xiao-Jun He

Journal of Electrochemistry

It is still a challenge to prepare carbon materials with high specific surface area at low cost from renewable resources. Herein, the authors report an efficient approach to synthesize porous carbons (PCs) from rice husk with ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6)) as a template and an activation agent. The as-made PCs featured the high specific surface area up to 1438 m2·g-1. As electrodes for supercapacitors, PCs showed a high specific capacitance of 256 F·g-1 at 0.05 A·g-1 in 6 mol·L-1 KOH aqueous electrolyte and a good rate performance of 211 F·g …


Polyaniline Coated Hollow Sulfur Prepared Using Sublimate 2,4,6-Tri(Propan-2-Yl)-1,3,5-Trioxane As Template For Sulfur Electrode, Zhang-Feng Li, Xiao-Rui Wang, Wen-Sheng Tian, Jin-Ze Yang, Ping Zhang, Li-Ping Ma, Yang Chen, Xiao-Li Cui, Zhi-Yu Jiang Dec 2019

Polyaniline Coated Hollow Sulfur Prepared Using Sublimate 2,4,6-Tri(Propan-2-Yl)-1,3,5-Trioxane As Template For Sulfur Electrode, Zhang-Feng Li, Xiao-Rui Wang, Wen-Sheng Tian, Jin-Ze Yang, Ping Zhang, Li-Ping Ma, Yang Chen, Xiao-Li Cui, Zhi-Yu Jiang

Journal of Electrochemistry

An advance method for preparing polyaniline-coated hollow sulfur material using sublimate material ADD(2,4,6-tri(propan-2-yl)-1,3,5-trioxane) as a template was developed for lithium-sulfur battery. At first, the smashed ADD particles were coated by a sulfur layer through the reaction of Na2S2O3 with diluted HCl. Then polyaniline layer was coated again on the surface of sulfur layer through the reaction of aniline with (NH4)2S2O8. After being dried at 60 oC for 12 h, the ADD in such a composite evaporated totally, and resulted in the formation of polyaniline-coated hollow sulfur …


Morphology Controlled Preparations And Electrochemical Properties Of Znco2O4 Electrode Materials For Supercapacitors, Yue-Shen Zhou, Meng Li, Shuang Wu, Zhao-Lei Li, Yan-Min Gao Dec 2019

Morphology Controlled Preparations And Electrochemical Properties Of Znco2O4 Electrode Materials For Supercapacitors, Yue-Shen Zhou, Meng Li, Shuang Wu, Zhao-Lei Li, Yan-Min Gao

Journal of Electrochemistry

In this work, hydrothermal reaction and high temperature were used to grow ZnCo2O4 active materials on Ni foam. The crystal stuctures and surface morphlogies of four samples were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The electrochemical performances were characterized by cyclic voltammetry (CV)、galvanostatic charge/discharge (GCD) testing and electrochemical impedance spectroscopy (EIS) on an electrochemical station. It can be seen that active materials tended to form denser stuctures with an increasing amount of NH4F in the solution system and four different morphologies of ZnCo2O …