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Enhancing the Hardness of Superhard Transition-Metal Borides: Molybdenum-Doped Tungsten Tetraboride † ‡ ‡ ‡ ‡ Reza Mohammadi,*, Christopher L
Article pubs.acs.org/cm Enhancing the Hardness of Superhard Transition-Metal Borides: Molybdenum-Doped Tungsten Tetraboride † ‡ ‡ ‡ ‡ Reza Mohammadi,*, Christopher L. Turner, Miao Xie, Michael T. Yeung, Andrew T. Lech, ‡ § ∥ ‡ § ∥ Sarah H. Tolbert, , , and Richard B. Kaner*, , , † Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia 23284, United States ‡ § ∥ Department of Chemistry and Biochemistry, Department of Materials Science and Engineering, and California NanoSystems Institute (CNSI), University of California, Los Angeles (UCLA), Los Angeles, California 90095, United States ABSTRACT: By creation of solid solutions of the recently explored low- cost superhard boride, tungsten tetraboride (WB4), the hardness can be increased. To illustrate this concept, various concentrations of molybdenum − (Mo) in WB4, that is, W1−xMoxB4 (x = 0.00 0.50), were systematically synthesized by arc melting from the pure elements. The as-synthesized samples were characterized using energy-dispersive X-ray spectroscopy (EDS) for elemental analysis, powder X-ray diffraction (XRD) for phase identification, Vickers microindentation for hardness testing, and thermal gravimetric analysis for determining the thermal stability limit. While the EDS analysis confirmed the elemental purity of the samples, the XRD results indicated that Mo is completely soluble in WB4 over the entire concentration range studied (0−50 at. %) without forming a second phase. When 3 at. % Mo is added to WB4, Vickers hardness values increased by about 15% from 28.1 ± 1.4 to 33.4 ± 0.9 GPa under an applied load of 4.90 N and from 43.3 ± 2.9 to 50.3 ± 3.2 GPa under an applied load of 0.49 N. -
Materials Design and Band Gap Engineering of Complex
University of Louisville ThinkIR: The University of Louisville's Institutional Repository Electronic Theses and Dissertations 8-2016 Materials design and band gap engineering of complex nanostructures using a semi-empirical approach : low dimensional boron nanostructures, h-BN sheet with graphene domains and holey graphene. Cherno Baba Kah Follow this and additional works at: https://ir.library.louisville.edu/etd Part of the Condensed Matter Physics Commons Recommended Citation Kah, Cherno Baba, "Materials design and band gap engineering of complex nanostructures using a semi- empirical approach : low dimensional boron nanostructures, h-BN sheet with graphene domains and holey graphene." (2016). Electronic Theses and Dissertations. Paper 2491. https://doi.org/10.18297/etd/2491 This Doctoral Dissertation is brought to you for free and open access by ThinkIR: The University of Louisville's Institutional Repository. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of ThinkIR: The University of Louisville's Institutional Repository. This title appears here courtesy of the author, who has retained all other copyrights. For more information, please contact [email protected]. MATERIALS DESIGN AND BAND GAP ENGINEERING OF COMPLEX : LOW NANOSTRUCTURES USING A SEMI-EMPIRICAL APPROACH , h DIMENSIONAL BORON NANOSTRUCTURES - BN SHEET WITH GRAPHENE DOMAINS AND HOLEY GRAPHENE By Cherno Baba Kah M.S, University of Louisville, 2013 M.S, Clark Atlanta University, 2011 B.S, University of The Gambia, -
Lecture 25: Main Group Chemistry
Lecture 23: Main Group Chemistry An Introduction We have spent the better part of the school year developing physical models to describe atomic structure, chemical bonding and the thermodynamics and kinetics physical and chemical phenomena. In all of that, however, we have been just as content to use generic symbols like A + B Æ C + D or to describe a weak acid as HA, as to actually assign it a real chemical structure with real chemical reactivity. In this chapter we right this wrong, working systematically through the main groups of the periodic table, learning for each group and particularly significant elements in those groups: • The natural forms in which the elements are found, including the hydrides and oxides • The famous chemical reactions that involve the chemical compounds containing those elements • The important practical uses of the compounds containing those elements. Common themes in Main Group Chemistry: We must have learned something useful during the year that will help to explain the chemistry of the main group elements. Here are some important themes that appear to explain pretty much everything that happens 1. The number of valence electrons in atoms drive the chemistry of a compound. And the main group number corresponds to the number of valence electrons 2. Compounds formed by main group elements pretty much always satisfy the octet rule if they can, achieving noble gas- like electronic configurations 3. There are trends in the periodic table that are pretty much determined by the effective nuclear charge and overall number of electrons in an atom. These trends are: a) atomic radius decreases moving to the right and up the periodic table b) ionization energy increases moving to the right and up the periodic table c) electronegativity increases to the right and up the periodic table d) polarizability increases to the right and down the periodic table e) non-metallic character increases to the right and up the periodic table 4. -
Wo 2010/141206 A2
(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (10) International Publication Number (43) International Publication Date 9 December 2010 (09.12.2010) WO 2010/141206 A2 (51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every B24D 11/00 (2006.01) B24B 27/06 (2006.01) kind of national protection available): AE, AG, AL, AM, B23D 61/18 (2006.01) B24D 3/00 (2006.01) AO, AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, DO, (21) International Application Number: DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, PCT/US2010/035227 HN, HR, HU, ID, IL, IN, IS, JP, KE, KG, KM, KN, KP, (22) International Filing Date: KR, KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD, 18 May 2010 (18.05.2010) ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PE, PG, PH, PL, PT, RO, RS, RU, SC, SD, (25) Filing Language: English SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, (26) Publication Language: English TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW. (84) Designated States (unless otherwise indicated, for every (30) Priority Data: 61/184,479 5 June 2009 (05.06.2009) US kind of regional protection available): ARIPO (BW, GH, GM, KE, LR, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, (71) Applicant (for all designated States except US): AP¬ ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ, PLIED MATERIALS, INC. -
Glossary of Terms
Glossary of Terms Acceptable Daily Intake or Allowed Daily Intake (ADI) → Dose- Response Relationship/Curve Allergen The allergen is a material which triggers an allergic reaction. Allopathy The term allopathy was created by Christian Friedrich Samuel Hahnemann (1755– 1843) (from the Greek prefix άλλος, állos, “other”, “different” and the suffix πάϑος, páthos, “suffering”) in order to distinguish his technique (homeopathy) from the traditional medicine of his age. Today, allopathy means a medicine based on the principles of modern pharmacology. Anaphylactic shock Anaphylaxis (or an anaphylactic shock) is a whole-body, rapidly developing aller- gic reaction, which may lead to lethal respiratory and circulatory failure. Antibody Antibodies are proteins produced by the immune system to neutralize exogenous (external) substances. Chromatography, chromatogram Chromatography is the common name of different techniques used to separate mix- tures of compounds. HPLC stands for high-performance liquid chromatography. A chromatogram is the pattern of separated substances obtained by chromatography. Colloidal sol A colloidal sol is a suspension of very small solid particles in a continuous liquid medium. Colloidal sols are quite stable and show the Tyndall effect (light scatter- ing by particles in a colloid). They can be quite stable. Examples include blood, pigmented ink, and paint. Colloidal sols can change their viscosity quickly if they © Springer International Publishing Switzerland 2014 311 L. Kovács et al., 100 Chemical Myths, DOI 10.1007/978-3-319-08419-0 312 Glossary of Terms are thixotropic. Examples include quicksand and paint, both of which become more fluid under pressure. Concentrations: parts per notations In British/American practice, the parts-per notation is a set of pseudo-units to de- scribe concentrations smaller than thousandths: 1 ppm (parts per million, 10−6 parts) One out of 1 million, e.g. -
The Measurements of Boron Concentration Rate in Water Using Curcumin Method and Ssntds Techniques
Available online a t www.pelagiaresearchlibrary.com Pelagia Research Library Advances in Applied Science Research, 2013, 4(1):105-112 ISSN: 0976-8610 CODEN (USA): AASRFC The measurements of boron concentration rate in water using curcumin method and SSNTDs Techniques *Thaer. M. Salman and Muntadher. A. Qasim Department of Physics, College of Education for Pure Science, University of Basrah, Basrah, Iraq _____________________________________________________________________________________________ ABSTRACT A technical method has been used two sets of experimental works in the measurements of Boron concentrations in water. The first measurement is by using curcumin method and the second is the passive method by using the solid state nuclear track detectors, CR39. Tap water in the governorate, has a very low Boron concentration 0.355 ppm atAl-Bedeah river, Al-Jzeera AlOula, did show a Boron level as high as 7.405 ppm at east governorate, while the waters have Boron level ranging between 7.785mg/l and 0.638 mg/l in curcumin method .A conclusion has been made, that Basra governorate tap water is safe as far as Boron concentration is concerned , while the rivers waters should be avoided. The high concentration tells us that pollutant in this part of city is larger than the other parts. Samples of water were collected during April 2011, from all locations in Basra City. Keywords : Neutron Source, Boron, Curcumin, SSNTD, Drinking water. _____________________________________________________________________________________________ INTRODUCTION Solid state nuclear track detectors (SSNTDs) of different materials are i mportant for investigations in basic science and tech nology [1] .Among such applications, SSNTDs are widely used in radiation protection and environmental radiation monitoring . -
Turmeric Curcuminoid Polyphenolics As Antioxidant and Anticarcinogenic Agents Ozlem Tokusoglu1*, Alkan Simsek2, Murtaza Parvizi3, Dilvin Eymen1
http://www.natscidiscovery.com OPEN ACCESS JOURNAL ISSN: 2149-6307 Natural Science and Discovery NSD 2015; 1(3): 56-61 Review Article DOI: 10.20863/nsd.50644 Turmeric curcuminoid polyphenolics as antioxidant and anticarcinogenic agents Ozlem Tokusoglu1*, Alkan Simsek2, Murtaza Parvizi3, Dilvin Eymen1 Abstract In this review content, it has been described the botanical and the chemical properties of turmeric (Curcuma longa), and its curcuminoid polyphenolic structures and antioxidant and anticarcinogenic influences on various cell proliferation and apoptosis. Besides it was emphasized the innovative anticarcinogen complex as boron- curcumin, and the safety evaluation with turmeric curcumin and the dose and toxicity in consuming for animals and human. Keywords: Turmeric, Curcuma longa, Antioxidant, Anticarcinogenic. Introduction Turmeric (Curcuma longa) is extensively consumed as a spice, food preservative, colouring food and agent and it is cultivated in India, South East Asia and China and other countries (Figure 1). Turmeric is a medicinal plant extensively used in Ayurveda, Unani and Siddha medicine as home remedy for various diseases (1). Dried turmeric powder is also utilized in sub-continental cooking and is the main ingredient in all forms of “curry” preparations. The wild turmeric is called C. aromatica and the domestic species is called C. longa. Turmeric has been described as C. longa by Linnaeus and its taxonomic profile is as follows (1) Class Liliopsida Subclass Commelinids Order Zingiberales Family Zingiberaceae Genus Curcuma Species Curcuma longa Curcuma longa, a perennial herb and member of the Zingiberaceae (ginger) family, grows to a height of 3- 5 feet with a tropical climate. It has oblong, pointed leaves and funnel-shaped yellow flowers (2) (Figure 1). -
Universite De Limoges
UNIVERSITE DE LIMOGES ECOLE DOCTORALE Science et Ingénierie en Matériaux, Mécanique, Energétique et Aéronautique (SI-MMEA) Laboratoire Science des Procédés Céramiques et de Traitements de Surface (SPCTS) Thèse pour obtenir le grade de DOCTEUR DE L’UNIVERSITÉ DE LIMOGES Discipline / Spécialité : Matériaux céramique et traitements de surface présentée et soutenue par Mathias GEORGES Thèse de doctorat Thèse de le 15 décembre 2016 Approche du frittage SPS de céramiques fines de carbure de bore : rôle des poudres initiales et de la mise en forme Thèse dirigée par Alexandre Maître, co-dirigée par Guy Antou, et co-encadrée par Nicolas Pradeilles JURY : Présidente M. Nathalie Moncoffre, Directeur de recherche CNRS, Université de Lyon, IPNL Rapporteurs M. Frédéric Bernard, Professeur, Université de Bourgogne, ICB M. Sébastien Mercier, Professeur, Université de Lorraine, LEM3 Examinateurs M. François Barthelemy, Ingénieur, DGA Bourge M. Grégory Etchegoyen, Docteur, Directeur du CTTC M. Nicolas Pradeilles, Maitre de Conférences, Université de Limoges, SPCTS (co-encadrant) M. Guy Antou, Maître de Conférences-HDR, Université de Limoges, SPCTS (co-directeur de thèse) M. Alexandre Maître, Professeur, Université de Limoges, SPCTS (directeur de thèse) GEORGES Mathias | Université de Limoges | 2017 A maman, partie trop tôt pour voir le fruit de son travail GEORGES Mathias | Université de Limoges | 2017 GEORGES Mathias | Université de Limoges | 2017 Remerciements J’aimerais tout d’abord remercier mon directeur de thèse, Alexandre Maître, pour sa confiance et ses précieux conseil. Mes remerciements s’adressent aussi à mes deux encadrants Guy Antou et Nicolas Pradeilles pour leurs disponibilités, leurs critiques qui m’ont permis de mener cette thèse à bien. -
Synthesis and Atomic Scale Investigation of Borophene on Au(111)
Synthesis and Atomic Scale Investigation of Borophene on Au(111) A thesis submitted towards partial fulfilment of BS-MS Dual Degree Programme By Navathej P Genesh (BS-MS student, Registration No.: 20121004) Under the guidance of Dr. Aparna Deshpande Department of Physics Indian Institute of Science Education and Research (IISER) Pune, India 1 2 3 Acknowledgements I would like to express my sincere gratitude to Dr. Aparna Deshpande for her valuable suggestions and guidance without which this project would not have come till this point. I also want to thank my lab members who have helped me throughout this year at all the phases of this project. I would like to thank Dr. Sumati Patil for the help in procuring boron powder. I am grateful to Rejaul for all his overnight discussions which made the course of this work easier. I also wanted to thank Thasneem, Imran and Nilesh Sir for their constant support. I am grateful to Nithin Raj PD, Anjana Raj, other friends and my family for their motivation and support. 4 TABLE OF CONTENTS List of Figures and List of Tables 7 List of Abbreviations 9 Abstract 10 INTRODUCTION 1.1 Introduction 11 1.2 Two dimensional materials 11 1.3 Boron 12 1.4 Borophene 13 METHODS 2.1 Scanning Tunneling Microscope (STM) 17 2.2 UHV - LT Scanning Tunneling Microscope: what is UHV and what is 20 LT? 2.3 Rotary pump 21 2.4 Turbo molecular pump 23 2.5 Titanium sublimation pump 24 2.6 Ion pump 25 2.7 Ion gauge 25 2.8 Pirani gauge 26 2.9 Noise reduction 27 2.10 Tip preparation 28 2.11 Sputtering and annealing 29 2.12 Molecular evaporator 29 2.13 Atomic force microscope (AFM) 30 2.14 Energy dispersive X-Ray analysis (EDAX) 31 2.15 Sample preparation 31 RESULTS AND DISCUSSION 3.1 Cleaning bare Au(111) 32 5 3.2 The first trial 36 3.3 Second trial 38 3.4 Third trial 39 3.5 Fourth trial 43 CONCLUSIONS AND OUTLOOK 45 BIBILIOGRAPHY 46 6 LIST OF FIGURES Figure Caption Page No. -
UCLA Electronic Theses and Dissertations
UCLA UCLA Electronic Theses and Dissertations Title Synthesis, Structure, and Properties of Refractory Hard-Metal Borides Permalink https://escholarship.org/uc/item/1hv5m731 Author Lech, Andrew Thomas Publication Date 2014 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA Los Angeles Synthesis, Structure, and Properties of Refractory Hard-Metal Borides A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Chemistry by Andrew Thomas Lech 2014 ©Copyright by Andrew Thomas Lech 2014 ABSTRACT OF THE DISSERTATION Synthesis, Structure, and Properties of Refractory Hard-Metal Borides by Andrew Thomas Lech Doctor of Philosophy in Chemistry University of California, Los Angeles, 2014 Professor Richard B. Kaner, Chair As the limits of what can be achieved with conventional hard compounds, such as tungsten carbide, are nearing reach, super-hard materials are an area of increasing industrial interest. The refractory hard metal borides, such as ReB 2 and WB 4, offer an increasingly attractive alternative to diamond and cubic boron nitride as a next-generation tool material. In this Thesis, a thorough discussion is made of the progress achieved by our laboratory towards understanding the synthesis, structure, and properties of these extremely hard compounds. Particular emphasis is placed on structural manipulation, solid solution formation, and the unique crystallographic manifestations of what might also be called “super- hard metals”. ii The dissertation of Andrew Thomas Lech is approved. ____________________________________________ Sarah Tolbert ____________________________________________ Vijay Gupta ____________________________________________ Richard B. Kaner, Committee Chair University of California, Los Angeles 2014 iii TABLE OF CONTENTS ABSTRACT OF THE DISSERTATION ......................................................................................................................... -
Techniques of Water-Resources Investigations of the United States Geological Survey
Techniques of Water-Resources Investigations of the United States Geological Survey Chapter A1 METHODS FOR DETERMINATION OF INORGANIC SUBSTANCES IN WATER AND FLUVIAL SEDIMENTS By Marvln J. Fishman and Linda C. Frledman, Editors First Edition 1970 Second Edition 1979 Third Edition 1989 Book 5 LABORATORY ANALYSIS UNITED STATES DEPARTMENT OF THE INTERIOR MANUEL LUJAN, JR., Secretary GEOLOGICAL SURVEY Dallas L. Peck, Director f UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1989 For sale by the Books and Open-File Reports Section, U.S. Geological Survey, Federal Center, Box 25425, Denver, CO 80225 Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. PREFACE A series of chapters on techniques describes methods used by the U.S. Geological Survey for planning and conducting water-resources investigations. The material is arranged under major subject headings called books and is further subdivided into sections and chapters. Book 5 is on laboratory analyses; section A is on water. The unit of publication, the chapter, is limited to a narrow field of subject matter. "Methods for Determination of Inorganic Substances in Water and Fluvial Sediments" is the first chapter under section A of book 5. The chapter number includes the letter of the section. This chapter was prepared with the assistance of many chemists and hydrolo gists of the U.S. Geological Survey as a means of documenting and making available the methods used by the U.S. Geological Survey to analyze water, water-sediment mixtures, and sediment samples. Any use of trade names, commercial products, manufacturers, or distributors is for descriptive purposes only and does not imply endorsement by the U.S. -
De Ning the True Hardness of Materials Harder Than Single Crystal Diamond
Dening the true hardness of materials harder than single crystal diamond Guodong (David) Zhan ( [email protected] ) Saudi Aramco (Saudi Arabia) Jin Liu Sichuan University Pei Wang High Pressure Science and Engineering Center, University of Nevada Liping Wang Southern University of Science and Technology https://orcid.org/0000-0002-6137-3113 Xiaozhi Yan High Pressure Science and Engineering Center, University of Nevada Yongtao Zou Shenzhen Technology University Duanwei He Sichuan University Chinthaka Gooneratne Saudi Aramco (Saudi Arabia) Jianhui Xu Saudi Aramco Alawi Alalsayednassir Saudi Aramco (Saudi Arabia) Timothy Moellendick Saudi Aramco (Saudi Arabia) Article Keywords: diamond, superhard materials, Vickers Hardness Tester Posted Date: June 25th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-614606/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Defining the true hardness of materials harder than single crystal diamond Jin Liu1,2,3, Guodong (David) Zhan4*, Pei Wang3, Liping Wang3*, Xiaozhi Yan3, Yongtao Zou5, Duanwei He1*, Chinthaka P. Gooneratne4, Jianhui Xu4, Alawi G Alalsayednassir,6 Timothy Eric Moellendick4 Affiliations: 1Institute of Atomic and Molecular Physics, Sichuan University; Chengdu 610065, People’s Republic of China. 2School of Mechanical Engineering, Jingchu University of Technology; Jingmen 44800, People’s Republic of China. 3Academy for Advanced Interdisciplinary Studies, and Department of Physics, Southern University of Science and Technology; Shenzhen 518055, People’s Republic of China. 4Drilling Technology Division, Exploration and Petroleum Engineering – Advanced Research Center; Saudi Aramco, Dhahran 31311, Saudi Arabia. 5College of Engineering Physics, and Center for Advanced Material Diagnostic Technology, Shenzhen Technology University; Shenzhen 518118, People’s Republic of China.