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2016

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Full-Text Articles in Physical Sciences and Mathematics

Bloom Filters Optimized Wu-Manber For Intrusion Detection, Monther Aldwairi, Koloud Al-Khamaiseh, Fatima Alharbi, Babar Shah Dec 2016

Bloom Filters Optimized Wu-Manber For Intrusion Detection, Monther Aldwairi, Koloud Al-Khamaiseh, Fatima Alharbi, Babar Shah

Journal of Digital Forensics, Security and Law

With increasing number and severity of attacks, monitoring ingress and egress network traffic is becoming essential everyday task. Intrusion detection systems are the main tools for capturing and searching network traffic for potential harm. Signature-based intrusion detection systems are the most widely used, and they simply use a pattern matching algorithms to locate attack signatures in intercepted network traffic. Pattern matching algorithms are very expensive in terms of running time and memory usage, leaving intrusion detection systems unable to detect attacks in real-time. We propose a Bloom filters optimized Wu-Manber pattern matching algorithm to speed up intrusion detection. The Bloom …


The Impact Of Md5 File Hash Collisions On Digital Forensic Imaging, Gary C. Kessler Dec 2016

The Impact Of Md5 File Hash Collisions On Digital Forensic Imaging, Gary C. Kessler

Journal of Digital Forensics, Security and Law

The Message Digest 5 (MD5) hash is commonly used as for integrity verification in the forensic imaging process. The ability to force MD5 hash collisions has been a reality for more than a decade, although there is a general consensus that hash collisions are of minimal impact to the practice of computer forensics. This paper describes an experiment to determine the results of imaging two disks that are identical except for one file, the two versions of which have different content but otherwise occupy the same byte positions on the disk, are the same size, and have the same hash …


Leveraging The Windows Amcache.Hve File In Forensic Investigations, Bhupendra Singh, Upasna Singh Dec 2016

Leveraging The Windows Amcache.Hve File In Forensic Investigations, Bhupendra Singh, Upasna Singh

Journal of Digital Forensics, Security and Law

The Amcache.hve is a registry hive file that is created by Microsoft® Windows® to store the information related to execution of programs. This paper highlights the evidential potential of Amcache.hve file and its application in the area of user activity analysis. The study uncovers numerous artifacts retained in Amcache.hve file when a user performs certain actions such as running host-based applications, installation of new applications, or running portable applications from external devices. The results of experiments demonstrate that Amcache.hve file stores intriguing artifacts related to applications such as timestamps of creation and last modification of any application; name, description, publisher …


The 2016 Analysis Of Information Remaining On Computer Hard Disks Offered For Sale On The Second Hand Market In The Uae, Thomas Martin, Andy Jones, Mohammed Alzaabi Dec 2016

The 2016 Analysis Of Information Remaining On Computer Hard Disks Offered For Sale On The Second Hand Market In The Uae, Thomas Martin, Andy Jones, Mohammed Alzaabi

Journal of Digital Forensics, Security and Law

This research describes our survey of data remaining on computer hard disks sold on the second hand market in the United Arab Emirates (UAE). This is a repetition of the first survey conducted in 2012 (Jones, Martin, & Alzaabi, 2012). Similar studies have been carried over the last ten years in the United Kingdom, Australia, USA, Germany and France: (Jones, Mee, Meyler, & Gooch, 2005), (Jones, Valli, Sutherland, & Thomas, 2006), (Jones, Valli, Dardick, & Sutherland, 2008), (Jones, Valli, Dardick, & Sutherland, 2009). This research was undertaken to gain insight into the volumes of data found on second-hand disks purchased …


A New Distributed Chinese Wall Security Policy Model, Saad Fehis, Omar Nouali, Mohand-Tahar Kechadi Dec 2016

A New Distributed Chinese Wall Security Policy Model, Saad Fehis, Omar Nouali, Mohand-Tahar Kechadi

Journal of Digital Forensics, Security and Law

The application of the Chinese wall security policy model (CWSPM) to control the information flows between two or more competing and/or conflicting companies in cloud computing (Multi-tenancy) or in the social network, is a very interesting solution. The main goal of the Chinese Wall Security Policy is to build a wall between the datasets of competing companies, and among the system subjects. This is done by the applying to the subjects mandatory rules, in order to control the information flow caused between them. This problem is one of the hottest topics in the area of cloud computing (as a distributed …


The Impact Of Sha-1 File Hash Collisions On Digital Forensic Imaging: A Follow-Up Experiment, Gary C. Kessler Dec 2016

The Impact Of Sha-1 File Hash Collisions On Digital Forensic Imaging: A Follow-Up Experiment, Gary C. Kessler

Journal of Digital Forensics, Security and Law

A previous paper described an experiment showing that Message Digest 5 (MD5) hash collisions of files have no impact on integrity verification in the forensic imaging process. This paper describes a similar experiment applied when two files have a Secure Hash Algorithm (SHA-1) collision.


A Survey Of Social Network Forensics, Umit Karabiyik, Muhammed Abdullah Canbaz, Ahmet Aksoy, Tayfun Tuna, Esra Akbas, Bilal Gonen, Ramazan S. Aygun Dec 2016

A Survey Of Social Network Forensics, Umit Karabiyik, Muhammed Abdullah Canbaz, Ahmet Aksoy, Tayfun Tuna, Esra Akbas, Bilal Gonen, Ramazan S. Aygun

Journal of Digital Forensics, Security and Law

Social networks in any form, specifically online social networks (OSNs), are becoming a part of our everyday life in this new millennium especially with the advanced and simple communication technologies through easily accessible devices such as smartphones and tablets. The data generated through the use of these technologies need to be analyzed for forensic purposes when criminal and terrorist activities are involved. In order to deal with the forensic implications of social networks, current research on both digital forensics and social networks need to be incorporated and understood. This will help digital forensics investigators to predict, detect and even prevent …


Nuclear Power: Black Sky Liability Or Black Sky Asset?, Sherrell R. Greene Dec 2016

Nuclear Power: Black Sky Liability Or Black Sky Asset?, Sherrell R. Greene

International Journal of Nuclear Security

Ready access to abundant electricity is a key enabler of modern life. During the past decade the vulnerability of Critical Infrastructure sectors in the U.S. to a variety of natural hazards and man-made threats has become increasingly apparent. The electrical infrastructure (the “Grid”) is the foundation for all other critical civil infrastructures upon which our society depends. Therefore, protection of the Grid is an energy security, homeland security, and national security issue of highest importance. Geomagnetic disturbances (GMD) induced by solar coronal mass ejections (CMEs), electromagnetic pulse (EMP) attacks, and cyber attacks are three events having the potential to plunge …


Table Of Contents Dec 2016

Table Of Contents

Journal of Digital Forensics, Security and Law

No abstract provided.


Generation Of Vector Partially Coherent Optical Sources Using Phase-Only Spatial Light Modulators, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao Dec 2016

Generation Of Vector Partially Coherent Optical Sources Using Phase-Only Spatial Light Modulators, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao

Faculty Publications

A simple and flexible optical system for generating electromagnetic or vector partially coherent sources or beams is presented. The alternative design controls field amplitude (beam shape), coherence, and polarization using only spatial light modulators. This improvement makes the apparatus simpler to construct and significantly increases the flexibility of vector partially coherent source generators by allowing many different types of sources to be produced without changing the physical setup. The system’s layout and theoretical foundations are thoroughly discussed. The utility and flexibility of the proposed system are demonstrated by producing a vector Schell-model and non-Schell-model source. The experimental results are compared …


Lithium-Sulfur (Selenium) Batteries: Interface Issues And Solving Strategies, Nian-Wu Li, Ya-Xia Yin, Yu-Guo Guo Dec 2016

Lithium-Sulfur (Selenium) Batteries: Interface Issues And Solving Strategies, Nian-Wu Li, Ya-Xia Yin, Yu-Guo Guo

Journal of Electrochemistry

The stable interface is still a challenge for lithium-sulfur (selenium) batteries because of the low conductivity of sulfur (selenium), dissolution of polysulfide (polyselenide), volume expansion of sulfur (selenium), and lithium dendrite growth. This review describers some recent developments in lithium-sulfur (selenium) batteries and highlights our efforts in this field. The possible strategies for building stable interface in the lithium-sulfur (selenium) batteries including nano-restriction effect, chemical bonding, interface adsorption, surface coating, electrolyte optimization, and Lithium anode treatment have been discussed.


Syntheses Of Ag@Pd@Pt Nanoparticles With Tunable Shell Thickness For Electrochemical Oxidation Of Formic Acid, Xiao-Dong Lin, Du-Hong Chen, Zhong-Qun Tian Dec 2016

Syntheses Of Ag@Pd@Pt Nanoparticles With Tunable Shell Thickness For Electrochemical Oxidation Of Formic Acid, Xiao-Dong Lin, Du-Hong Chen, Zhong-Qun Tian

Journal of Electrochemistry

In an effort to lower cost of a catalyst, the silver (Ag) core with palladium (Pd) layer then platinum (Pt) island (Ag@Pd@Pt) nanoparticles were synthesized and the electrocatalytic activity of Ag@Pd@Pt nanoparticles on formic acid was compared with that of Au@Pd@Pt nanoparticles reported previously. The results showed that the existence of a small amount of Pt could significantly improve the activity of the catalyst. When the surface coverage of Pt approached 0.5 monolayers, the activity of Ag@Pd@Pt nanoparticles reached the maximum. Though the onset potential of the electro-oxidation was slightly more positive (about 50 mV), the overall electrocatalytic activity of …


Intrinsic Interfacial Property Between High-Voltage Lini0.5Mn1.5O4 Cathode And Electrolyte, Li Li, Jing-Jing Xu, Shao-Jie Han, Wei Lu, Li-Wei Chen Dec 2016

Intrinsic Interfacial Property Between High-Voltage Lini0.5Mn1.5O4 Cathode And Electrolyte, Li Li, Jing-Jing Xu, Shao-Jie Han, Wei Lu, Li-Wei Chen

Journal of Electrochemistry

To obtain high energy density, developing high-voltage cathode materials is an effective approach. The cathode/electrolyte interface stability is the key factor for the cycle performance and safety performance of high-voltage lithium ion batteries. It is, therefore, of significant importance to study the stability of cathode/electrolyte interface. However, many reports have shown that at the cathode/electrolyte interface the cathodes were prepared by coating the mixture of active materials with a conductive additive and a binder on an Al current collector. The introduction of additives will interfere the surface morphology and component analyses, resulting in difficulty to acquire the intrinsic information at …


Lithium Plating Identification From Degradation Behaviors Of Lithium-Ion Cells, Jian-Bo Zhang, Lai-Suo Su, Xin-Yu Li, Hao Ge, Ya-Kun Zhang, Zhe Li Dec 2016

Lithium Plating Identification From Degradation Behaviors Of Lithium-Ion Cells, Jian-Bo Zhang, Lai-Suo Su, Xin-Yu Li, Hao Ge, Ya-Kun Zhang, Zhe Li

Journal of Electrochemistry

Lithium plating has huge impact on the lifetime and safety of lithium-ion cells. It is, therefore, necessary to identify lithium plating. In this study, the accelerated stress tests of lithium-ion cells were conducted under different conditions with multi-stress loads. Based on the different effects of the two major aging mechanisms, namely, SEI (Solid Electrolyte Interface) layer growth and lithium plating, on the degradation behaviors, two lithium plating identification methods of resistance-capacity plot and Arrhenius plot were employed. The experimental results revealed that the two identification methods are highly consistent with each other. Furthermore, the origins of capacity loss were distinguished …


Stm Investigation Of Oxygen Reduction Reaction On Solid Interface In Fuel Cell, Zhen-Feng Cai, Bing Sun, Wen-Jie Jiang, Ting Chen, Dong Wang, Li-Jun Wan Dec 2016

Stm Investigation Of Oxygen Reduction Reaction On Solid Interface In Fuel Cell, Zhen-Feng Cai, Bing Sun, Wen-Jie Jiang, Ting Chen, Dong Wang, Li-Jun Wan

Journal of Electrochemistry

An electrocatalyst for oxygen reduction reaction (ORR) is an important component for fuel cells. An investigation at interfacial electrochemical reactions toward ORR at a molecular scale benefits mechanistic understanding as well as rational design of catalysts. Scanning tunneling microscopy (STM) has been proven to be a powerful tool to monitor chemical reactions and to provide in-situ information about the interfacial electrochemical reactions at a molecular level. This review summarizes the recent STM studies in monitoring the interface processes such as morphological changes, molecular changes, reaction intermediates, and oxidation products. The prospects of future development in this field are outlined.


A Study On The Oxidation Of Hydrogen Peroxide At Au(111) And Au(100) Electrodes, Yong-Li Zheng, Jie Wei, Yan-Xia Chen Dec 2016

A Study On The Oxidation Of Hydrogen Peroxide At Au(111) And Au(100) Electrodes, Yong-Li Zheng, Jie Wei, Yan-Xia Chen

Journal of Electrochemistry

The oxidation reactions of hydrogen peroxide (H2O2) at Au(111) and Au(100) electrodes in 0.1 mol·L-1 HClO4 were investigated by using rotating disk electrode system. It was found that H2O2 could be readily oxidized to O2 at both Au(100) and Au(111) surfaces with the onset potential close to its equilibrium potential. In contrast, the onset overpotential for H2O2 reduction was above 0.4 V, while the onset overpotential for H2O2 oxidation at Au(100) was ca. 0.1 V more negative than that at Au(111), this is probably …


Chitosan/Nonahydrate Gel Derived Fe-N-Doped Porous Carbon Sheet As High-Efficient Orr Electrocatalyst, Fan-Lu Meng, Xin-Bo Zhang, Jun-Min Yan Dec 2016

Chitosan/Nonahydrate Gel Derived Fe-N-Doped Porous Carbon Sheet As High-Efficient Orr Electrocatalyst, Fan-Lu Meng, Xin-Bo Zhang, Jun-Min Yan

Journal of Electrochemistry

The chitosan/nonahydrate gel was used as a precursor to realize the uniform mixture of N-polymer and metal salt. After lyophilization treatment, the gel went through heat treatment and acid etch. Accordingly, the Fe-N-doped porous carbon sheet with homogenous composition and microstructure was prepared. Compared with the commercial Pt/C catalyst, the Fe-N-doped porous carbon sheet exhibited more positive onset potential and half-wave potential, higher current density, and especially, excellent durability. The power density of 318 mW·cm-2 was obtained in alkaline fuel cell with the Fe-N-doped porous carbon sheet as a cathode catalyst, which is higher than 267 mW·cm-2 with …


Synthesis Of Ultrathin Co3O4 Nanoflakes Film Material For Electrochemical Sensing, Hui-Juan Wang Dec 2016

Synthesis Of Ultrathin Co3O4 Nanoflakes Film Material For Electrochemical Sensing, Hui-Juan Wang

Journal of Electrochemistry

Ultrathin cobalt oxide (Co3O4 ) nanoflakes film material was synthesized by using an electro-deposited cobalt layer as a raw material through a simple oxidation method and followed by a heat treatment at 350 oC. The physical characterizations of the Co3O4 nanoflakes film were performed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) technologies, and the electrochemical activity was measured by cyclic voltammetry (CV). As a promising material for electrochemical sensing, the as-synthesized ultrathin Co3O4 nanoflakes film material exhibited excellent electrochemical activity for H2O …


Scatterometry Of 50 Nm Half Pitch Features, Ruichao Zhu Dec 2016

Scatterometry Of 50 Nm Half Pitch Features, Ruichao Zhu

Optical Science and Engineering ETDs

Metrology technologies are an essential adjunct to Integrated Circuit (I.C.) Semiconductor manufacturing. Scatterometry, an optical metrology, was chosen to measure 50 nm half pitch feature structures. A bread-board scatterometry system has been assembled to provide a non-contact, non-destructive, accurate and flexible measurement. A real-time, on-line scatterometry system has also been demonstrated and proven to provide a high throughput measurement.

Three different types of samples have been measured using the scatterometry setup. The wire-grid polarizer (WGP) sample has been made by Jet and Flash Nanoimprint Lithography with ~100 nm pitch and ~50 nm wide ~200 nm tall Al gratings on fused …


Algorithm For Premature Ventricular Contraction Detection From A Subcutaneous Electrocardiogram Signal, Iris Lynn Shelly Dec 2016

Algorithm For Premature Ventricular Contraction Detection From A Subcutaneous Electrocardiogram Signal, Iris Lynn Shelly

Dissertations and Theses

Cardiac arrhythmias occur when the normal pattern of electrical signals in the heart breaks down. A premature ventricular contraction (PVC) is a common type of arrhythmia that occurs when a heartbeat originates from an ectopic focus within the ventricles rather than from the sinus node in the right atrium. This and other arrhythmias are often diagnosed with the help of an electrocardiogram, or ECG, which records the electrical activity of the heart using electrodes placed on the skin. In an ECG signal, a PVC is characterized by both timing and morphological differences from a normal sinus beat.

An implantable cardiac …


Grnsight: A Web Application And Service For Visualizing Models Of Small- To Medium-Scale Gene Regulatory Networks, Kam D. Dahlquist, John David N. Dionisio, Ben G. Fitzpatrick, Nicole A. Anguiano, Anindita Varshneya, Britain J. Southwick, Mihir Samdarshi Dec 2016

Grnsight: A Web Application And Service For Visualizing Models Of Small- To Medium-Scale Gene Regulatory Networks, Kam D. Dahlquist, John David N. Dionisio, Ben G. Fitzpatrick, Nicole A. Anguiano, Anindita Varshneya, Britain J. Southwick, Mihir Samdarshi

John David N. Dionisio

GRNsight is a web application and service for visualizing models of gene regulatory networks (GRNs). A gene regulatory network (GRN) consists of genes, transcription factors, and the regulatory connections between them which govern the level of expression of mRNA and protein from genes. The original motivation came from our efforts to perform parameter estimation and forward simulation of the dynamics of a differential equations model of a small GRN with 21 nodes and 31 edges. We wanted a quick and easy way to visualize the weight parameters from the model which represent the direction and magnitude of the influence of …


College Of Engineering Senior Design Competition Fall 2016, University Of Nevada, Las Vegas Dec 2016

College Of Engineering Senior Design Competition Fall 2016, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge. The senior design competition helps focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects on …


Vulnerability Analysis And Security Framework For Zigbee Communication In Iot, Charbel Azzi Dec 2016

Vulnerability Analysis And Security Framework For Zigbee Communication In Iot, Charbel Azzi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Securing IoT (Internet of Things) systems in general, regardless of the communication technology used, has been the concern of many researchers and private companies. As for ZigBee security concerns, much research and many experiments have been conducted to better predict the nature of potential security threats. In this research we are addressing several ZigBee vulnerabilities by performing first hand experiments and attack simulations on ZigBee protocol. This will allow us to better understand the security issues surveyed and find ways to mitigate them. Based on the attack simulations performed and the survey conducted, we have developed a ZigBee IoT framework …


Acoustic Detection, Source Separation, And Classification Algorithms For Unmanned Aerial Vehicles In Wildlife Monitoring And Poaching, Carlo Lopez-Tello Dec 2016

Acoustic Detection, Source Separation, And Classification Algorithms For Unmanned Aerial Vehicles In Wildlife Monitoring And Poaching, Carlo Lopez-Tello

UNLV Theses, Dissertations, Professional Papers, and Capstones

This work focuses on the problem of acoustic detection, source separation, and classification under noisy conditions. The goal of this work is to develop a system that is able to detect poachers and animals in the wild by using microphones mounted on unmanned aerial vehicles (UAVs). The classes of signals used to detect wildlife and poachers include: mammals, birds, vehicles and firearms. The noise signals under consideration include: colored noises, UAV propeller and wind noises.

The system consists of three sub-systems: source separation (SS), signal detection, and signal classification. Non-negative Matrix Factorization (NMF) is used for source separation, and random …


Plasmonic Devices Based On Transparent Conducting Oxides For Near Infrared Applications, Kim Jongbum Dec 2016

Plasmonic Devices Based On Transparent Conducting Oxides For Near Infrared Applications, Kim Jongbum

Open Access Dissertations

In the past decade, there have been many breakthroughs in the field of plasmonics and nanophotonics that have enabled optical devices with unprecedented functionalities. Even though remarkable demonstration of at photonic devices has been reported, constituent materials are limited to the noble metals such as gold (Au) and silver (Ag) due to their abundance of free electrons which enable the support of plasmon resonances in the visible range. With the strong demand for extension of the optical range of plasmonic applications, it is now a necessity to explore and develop alternative materials which can overcome intrinsic issues of noble metals …


Enhancements In Localized Classification For Uterine Cervical Cancer Digital Histology Image Assessment, Peng Guo, Haidar A. Almubarak, Koyel Banerjee, R. Joe Stanley, L. Rodney Long, Sameer K. Antani, George R. Thoma, Rosemary E. Zuna, Shelliane R. Frazier, Randy Hays Moss, William V. Stoecker Dec 2016

Enhancements In Localized Classification For Uterine Cervical Cancer Digital Histology Image Assessment, Peng Guo, Haidar A. Almubarak, Koyel Banerjee, R. Joe Stanley, L. Rodney Long, Sameer K. Antani, George R. Thoma, Rosemary E. Zuna, Shelliane R. Frazier, Randy Hays Moss, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

Background: In previous research, we introduced an automated, localized, fusion-based approach for classifying uterine cervix squamous epithelium into Normal, CIN1, CIN2, and CIN3 grades of cervical intraepithelial neoplasia (CIN) based on digitized histology image analysis. As part of the CIN assessment process, acellular and atypical cell concentration features were computed from vertical segment partitions of the epithelium region to quantize the relative distribution of nuclei.

Methods: Feature data was extracted from 610 individual segments from 61 images for epithelium classification into categories of Normal, CIN1, CIN2, and CIN3. The classification results were compared against CIN labels obtained from two pathologists …


Identity‐Based Schemes For A Secured Big Data And Cloud Ict Framework In Smart Grid System, Feng Ye, Yi Qian, Rose Qingyang Hu Dec 2016

Identity‐Based Schemes For A Secured Big Data And Cloud Ict Framework In Smart Grid System, Feng Ye, Yi Qian, Rose Qingyang Hu

Electrical and Computer Engineering Faculty Publications

Smart grid is an intelligent cyber physical system (CPS). The CPS generates a massive amount of data for efficient grid operation. In this paper, a big data‐driven, cloud‐based information and communication technology (ICT) framework for smart grid CPS is proposed. The proposed ICT framework deploys hybrid cloud servers to enhance scalability and reliability of smart grid communication infrastructure. Because the data in the ICT framework contains much privacy of customers and important data for automated controlling, the security of data transmission must be ensured. In order to secure the communications over the Internet in the system, identity‐based schemes are proposed …


Fabrication Of Infrared Photodetectors Utilizing Lead Selenide Nanocrystals, Justin Anthony Hill Dec 2016

Fabrication Of Infrared Photodetectors Utilizing Lead Selenide Nanocrystals, Justin Anthony Hill

Graduate Theses and Dissertations

Colloidal lead selenide and lead selenide / lead sulfide core/shell nanocrystals were grown using a wet chemical synthesis procedure. Absorbance and photoluminescence measurements were made to verify the quality of the produced nanocrystals. Absorbance spectra were measured at room temperature, while photoluminescence spectra were measured at 77 K. Organic ligands were exchanged for shorter ligands in order to increase the conductivity of the nanocrystals. Absorption and PL spectra for both core and core/shell nanocrystals were compared. Interdigital photodetector devices with varying channel widths were fabricated by depositing gold onto a glass substrate. Lead selenide nanocrystals were deposited onto these metallic …


Dual Role Of Sb Ions As Electron Traps And Hole Traps In Photorefractive Sn2P2S6 Crystals, Brant E. Kananen, Eric M. Golden, Sergey A. Basun, D. R. Evans, A. A. Grabar, I. M. Stoika, John W. Mcclory, Nancy C. Giles, Larry E. Halliburton Dec 2016

Dual Role Of Sb Ions As Electron Traps And Hole Traps In Photorefractive Sn2P2S6 Crystals, Brant E. Kananen, Eric M. Golden, Sergey A. Basun, D. R. Evans, A. A. Grabar, I. M. Stoika, John W. Mcclory, Nancy C. Giles, Larry E. Halliburton

Faculty Publications

Doping photorefractive single crystals of Sn2P2S6 with antimony introduces both electron and hole traps. In as-grown crystals, Sb3+ (5s2) ions replace Sn2+ ions. These Sb3+ ions are either isolated (with no nearby perturbing defects) or they have a charge-compensating Sn2+ vacancy at a nearest-neighbor Sn site. When illuminated with 633 nm laser light, isolated Sb3+ ions trap electrons and become Sb2+ (5s25p1) ions. In contrast, Sb3+ ions with an adjacent Sn vacancy trap holes during illumination. The hole is primarily …


Interactive Physics And Characteristics Of Photons And Photoelectrons In Hyperbranched Zinc Oxide Nanostructures, Garrett Edward Torix Dec 2016

Interactive Physics And Characteristics Of Photons And Photoelectrons In Hyperbranched Zinc Oxide Nanostructures, Garrett Edward Torix

Graduate Theses and Dissertations

As is commonly known, the world is full of technological wonders, where a multitude of electronic devices and instruments continuously help push the boundaries of scientific knowledge and discovery. These new devices and instruments of science must be utilized at peak efficiency in order to benefit humanity with the most advanced scientific knowledge. In order to attain this level of efficiency, the materials which make up these electronics, or possibly more important, the fundamental characteristics of these materials, must be fully understood. The following research attempted to uncover the properties and characteristics of a selected family of materials. Herein, zinc …