...Crystals While doing research on my project I found out a lot of things about crystals. I found out that crystals are solids that form by a regular repeated pattern of molecules connecting together. The salt in the kitchen, the snow, and the diamond in a ring are all crystals. The word crystal comes from a Greek word”krysos” which means “ice cold”. It was believed that crystals were a type of ice that was so cold it never melts. Crystals can form in a lot of different shapes. The shapes range from cubes, hexagons, double pyramids to name a few. My crystal shaped into a sphere but usually they are symmetrical from one side to other, but many types of crystals are not. The shape of the crystal is determined by the chemical components inside the crystal and the chemical bonds between the atoms and molecules. The atoms in smallest building block of a crystal are called a “Unit Cell” The atoms in each unit cell are held together by electrical forces or bonds. When a lot of unit cells are near each other they arrange themselves in different patterns. They attract one another in some directions more than others. This pattern gives the crystal their shape with symmetrical surfaces called facets. Crystals also comes in many different colors, from clear diamonds, to red rubies, to blue sapphires and more they get there color from the materials that make up the crystals. The colors come from the color of the spectrum that the crystal does not absorb. They are used for a lot of different...
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...Objective: To demonstrate the way crystals grow and how they affect the behavior of material. A comparison can also be made between the growth of the crystals in metals and non-metals. Equipment: Hot plates, glass plates, beakers, glass rods, scale to weigh out the salt, graduated flask for water, furnace, crucibles, sand, tongs, safety glasses and gloves. Starting materials: Epsom salts, water, 50% Aluminum - 50% Copper alloy (previously alloyed). Safety: Whenever you are dealing with hot liquids, there is the potential for burns and spills. Protect yourself from the possible risks, especially around the hot metal. Make sure you know where any potential spillage will go and place something in the way to protect yourself. In part ‘B’ be especially careful of the hot metal. Remember, it will still be very hot, even when it has changed back into a solid. Procedure: Part A: A supersaturated solution of salt will separate out into crystals on cooling. The size of the crystals is a function of the rate of cooling, the amount of impurities present and the degree of supersaturation (concentration of salt present in the solution). 1. Dissolve 25 grams of Epsom salts in 25 ml of water. Heat the water until all the salt dissolves, but keep the water below the boiling point. If all the salt will not dissolve, add water in small quantities until it does. Pour some of the solution onto a clean glass plate so as to form a thin film and watch it solidify. If it solidifies too rapidly...
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...Polymer-stabilized blue phase liquid crystals: a tutorial [Invited] Jin Yan and Shin-Tson Wu* College of Optics and Photonics, University of Central Florida, Orlando, FL 32816, USA *swu@mail.ucf.edu Abstract: Blue phase liquid crystals exhibit several attractive features, such as self-assembled three-dimensional cubic structures, optically-isotropic in the voltage-off state, no need for alignment layers, and submillisecond response time. This tutorial gives step-by-step introduction on basic bluephase materials and properties, monomers and polymerization processes, and key device performance criteria for display and photonics applications. ©2011 Optical Society of America OCIS codes: (160.3710) Liquid crystals; (160.5470) Polymers. References and links 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. F. Reinitzer, “Beiträge zur Kenntniss des Cholestherins,” Monatsh. Chem. 9(1), 421–441 (1888). A. Saupe, “On molecular structure and physical properties of thermotropic liquid crystals,” Mol. Cryst. Liq. Cryst. (Phila. Pa.) 7(1), 59–74 (1969). S. A. Brazovskii and S. G. Dmitriev, “Phase transitions in cholesteric liquid crystals,” Zh. Eksp. Teor. Fiz. 69, 979–989 (1975). R. M. Hornreich and S. Shtrikman, Liquid Crystals of One- and Two- Dimensional Order (Springer-Verlag, Berlin, 1980). S. Meiboom, J. P. Sethna, W. P. Anderson, and W. F. Brinkman, “Theory of the blue phase cholesteric liquid crystals,” Phys. Rev. Lett. 46(18), 1216–1219 (1981)...
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...Molecular Crystal Structures Crystalline and amorphous are the two categories of solids. Crystalline solids are those that have a long range order and are rigid. This means that the atoms, molecules or ions are in a specific position. Glass is an example of the other category of solids and is an amorphous solid. Amorphous solids are different than crystalline since these solids do not have a structured arrangement and long-range order of molecules. Crystalline solids have a structure that has a lattice characteristic and is most efficient when closely packed together. Ionic, covalent, molecular, and metallic are the four types of crystals. These crystals are different because of their structures and properties that include their melting point, hardness, density forces that hold the crystal particles together. This method can be applied to various areas of drug research, quality control and manufacturing. Examining the changes in the crystal structures, using the low frequency light waves can be applied to how a human body absorbs drugs. The need was discovered when a certain drug was not used right away. The drug structure changed into a crystallized solid and was not able to be dissolved or absorbed by the human body in this state. The London dispersion forces help to predict crystal structures of many different substances. There are many different environmental factors that can affect how crystals form. Those factors include humidity, temperature, and light....
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...Liquid Crystal Display PHY 101: Mechanics Topic: -LIQUID CRUSTAL DISPLAY DOA: 28/08/2010 DOR: 28/09/2010 DOS: 10/11/2010 Submitted to: Submitted By: Ms. Neeti Walia Deptt. of Physics Roll. No. A13 Sec: E4001 Reg. No: 11007103 ACKNOWLEDGEMENT I take this opportunity to present my votes of thanks to all those guidepost who really acted as lightening pillars to enlighten our way throughout this project that has led to successful and satisfactory completion of This study. We are highly thankful to Miss NEETI WALIA for her active support, valuable time and advice, whole-hearted guidance, sincere cooperation and pains-taking involvement during the study and in completing the assignment of preparing the said project within the time stipulated. Lastly, We are thankful to all those, particularly the various friends , who have been instrumental in creating proper, healthy and conductive environment and including new and fresh innovative ideas for us during the project, their help, it would have been extremely difficult for us to prepare the project in a time bound framework. TABLE OF CONTENTS:- INTRODUCTION WHAT IS LCD THEORY OF LCD TYPES OF LCD PASSIVE-MATRIX ADDRESSED LCD ACTIVE-MATRIX ADDRESED LCD ADVANTAGE N DISADVANTAGE COLOUR DISPLAY APPLICATIONS OF LCD BIBLIOGRAPHY LIQUID CRYSTAL DISPLAY INTRODUCTION:- LCDs are super-thin displays that are...
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...Liquid Crystal Display The LCD is used for the purpose of displaying the words which we are given in the program code. This code will be executed on microcontroller chip. By following the instructions in code the LCD display the related words. Fig.5.6 shows the LCD display. 5.3.1 Introduction [pic] Fig. 5.6: LCD Display The LCD display consists of two lines, 20 characters per line that is interfaced with the PIC16F73.The protocol (handshaking) for the display is as shown in Fig. The display contains two internal byte-wide registers, one for commands (RS=0) and the second for characters to be displayed (RS=1). It also contains a user-programmed RAM area (the character RAM) that can be programmed to generate any desired character that can be formed using a dot matrix. To distinguish between these two data areas, the hex command byte 80 will be used to signify that the display RAM address 00h will be chosen Port1 is used to furnish the command or data type, and ports 3.2 to 3.4 furnish register select and read/write levels. Theory A liquid crystal is a material (normally organic for LCDs) that will flow like a liquid but whose molecular structure has some properties normally associated with solids. The Liquid Crystal Display (LCD) is a low power device. The power requirement is typically in the order of microwatts for the LCD. However, an LCD requires an external or internal light source. It is limited to a temperature range of about 0°C to 60°C and lifetime...
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...sincere cooperation and pains-taking involvement during the study and in completing the assignment of preparing the said project within the time stipulated. Lastly, We are thankful to all those, particularly the various friends , who have been instrumental in creating proper, healthy and conductive environment and including new and fresh innovative ideas for us during the project, their help, it would have been extremely difficult for us to prepare the project in a time bound framework. TABLE OF CONTENTS:- INTRODUCTION WHAT IS LCD THEORY OF LCD TYPES OF LCD PASSIVE-MATRIX ADDRESSED LCD ACTIVE-MATRIX ADDRESED LCD ADVANTAGE N DISADVANTAGE COLOUR DISPLAY APPLICATIONS OF LCD BIBLIOGRAPHY LIQUID CRYSTAL DISPLAY INTRODUCTION:- LCDs are super-thin displays that are used in laptop computer screens and flat panel monitors. Smaller LCDs are used in handheld TVs, PDAs, and portable video game devices. The image on an LCD screen is created by sandwiching an electrically reactive substance between two electrodes. This colour a type of display used in digital watches and many portable computers. LCD displays utilize two sheets of polarizing material with a liquid...
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...TERM PAPER Topic:LCD (LIQUED CRYSTAL DISPLAY) DOA: 22/02/2010 DOS: 06/05/2010 Submitted to: Submitted by: Bindu ABSTRACT LCD projectors are becoming smaller and less expensive, and are starting to incorporate built-in light sources and speakers. LCD panels are also improving in resolution and response. An LCD panel is fairly light and thin, but require a separate overhead projector. The LCD projector contains its own light source, so no overhead projector is required. These have more multimedia features than LCD panels, and usually include speakers and multiple inputs and outputs. Polysilicone LCDs are smaller, and allow more light to pass through than thin-film transistor LCDs. LCD projectors typically weigh between 10 to 50 pounds. Heavier ones are also available that can achieve movie screen quality, although these are more costly, and better suited to permanent installations. Most LCD panel devices have a screen of between 8.4 and 10.4 inches diagonally. A good panel or projector will also provide on-screen adjustment, remote control and a hard shell carrying case. ACKNOWLEDGEMENT I take this opportunity to present my votes of thanks to all those guidepost who really acted as lightening pillars to enlighten our way throughout this project that has led to successful and satisfactory completion of this study. Name-Rahul Rawat ...
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...differences – How data is converted to colors on the LCD LCD signal interface and timing parameters – LCD signals and timing – Controlling the backlight Introduction to frame buffers with the LPC32x0 MCU – How graphics data is stored in memory – Color depth and lookup tables System considerations for LCD based systems – Mapping LCD data signals to the LCD controller signals – LCD data bandwidth Examples Passive and active LCD technologies How an LCD works An array of Liquid Crystal segments – When not in an electrical field, crystals are organized in a random pattern – When an electric field is applied, the crystals align to the field – The crystals themselves do not emit light, but ‘gate’ the amount of light that can pass through them • Crystals aligned perpendicular to a light source will prevent light from passing through them Each LCD segment is aligned with an electric field A light source (backlight) is needed to drive light through the aligned crystal field Courtesy of Sharp Passive displays Passive LCD panels – Consists of a grid of row and columns electrical signals – Columns and rows connect perpendicularly to every segment in the LCD • Columns and rows are multiplexed to many different segments – An IC controls which column and row are selected to enable or disable the segment at the row/column intersection – A small bias is applied to the row and column to generate a field at the intersection • • No charge is stored at the segment...
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...Merlin does not feel any satisfaction in doing this, or is capable of resisting it. One clear opportunity he had of retaliating was in the case of Dinias, for Dinias bullied Merlin as a child. Yet, when they met again and had matured, Merlin did not let the demons of the past affect his present. Though Merlin had the motive and opportunity to strike against his harassers, he chooses not to, and acts as a far more civilized and admirable man. 2. Choose three other characters in the book and in bulleted paragraphs (one per character) discuss how, why, and what Stewart’s tones (attitudes) reveal about human beings. Make sure your answers include her thoughts and are complete enough, with good examples, to show you read this book. In The Crystal Cave, Mary Stewart’s reveals her attitude that human superstition is ridiculous through the magician Maugan. Maugan is portrayed as a man who believes in superstition, and this later creates issues for Merlin. Vortigern was constructing a fortress, but it would not stand higher than a man’s height; Maugan manages to convince his king, Vortigern, that the blood of a man who has no father must be spilled onto the foundation of his fortress. Merlin, who they believe has no human father, is the would-be sacrifice for this deed. Stewart portrays this logic as foolish, and through Merlin, calls Maugan a “charlatan”. This shows Mary Stewart’s true feelings about superstition as well; such beliefs are only held by misled people or frauds. Stewart...
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...OPTIMIZATION OF TWO DIMENSIONAL PHOTONIC CRYSTAL BAND GAP USING INDIUM PHOSPHIDE(InP) A thesis submitted in partial fulfilment of the requirements of Staffordshire University for the degree of Master of Science in Electronics Engineering Faculty of Computing, Engineering & Technology DECEMBER 2010 ABSTRACT Photonic crystals exhibit periodic structure and these are of many types such as one, two and three dimensional photonic crystals. Photonic crystal is a low loss periodic dielectric medium. In order to cover all periodic directions the gap must be extend to certain length which is equivalent to semiconductor band gap. The complete photonic band gap occurs in the three dimensional photonic crystals. The propagation of light which is confined to a particular direction can be analysed through Maxwell’s approach. The electromagnetic wave which contains both ‘E’ and ‘H’ fields can be calculated through these equations. These field vectors are more useful in calculating band structure of photonic crystal. This report deals with the calculation of band structure in two-dimensional photonic crystal. There are many methods for calculating band structure and this thesis is mainly focused on the plane wave expansion method. This report contains the simulation procedure for calculating band structure for both TE and TM modes in the presence of dielectric medium using Computer Simulation Technology (CST) microwave studio. Results which are obtained during the simulation provide...
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...experiment is to see how salol crystals will form when they are melted and the only way to make them solid again. Introduction: Is there a preferred crystal shape for solid salol? Rhombus Is cooling liquid salol a 100% effective way to cause solidification? No, it is not. Procedure: 1) Obtain a slide of solid salol, two magnifying glasses, and a match book. 2) Use a magnifying glass to look at the crystal and describe what you see. 3) Scratch off some of the crystal from the smaller side and save it on your desk. 4) Light a match and heat the bigger crystal side and time how many seconds it takes for the crystal to reach its melting point. 5) Let the melted crystal cool to room temperature and see if it has solidified. 6) Add a small piece of the crystal you previously scratch off onto the desk, and put it into the cooled crystal. 7) After you watch the crystal solidify again, heat the crystal up again. 8) This time, add a piece of lead, paper, or a piece of the match, and see if the solution solidifies. Observation: The crystal is flaky, shiny, and white. It is lumpy in some parts and flat in others. The crystals are in a shape of a rhombus. It took about 7 seconds for the crystal to melt. After adding the lead to the crystal, the lead did nothing. It did not re-solidify the crystal. Conclusions: After melting the crystal, the crystal does not solidify at room temperature. It does, however, re-solidify when solid crystal is added to it. We can...
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...in the development of pharmaceutical dosage form Polymorphism comes from the Greek words, Polus = many and morph = shape. Polymorphism means existence of substance in more than one form. Many pharmaceutical solids can exist in different physical forms. Polymorphism is often characterized as the ability of a drug substance to exist as two or more crystalline phases that have different arrangements and/or conformations of the molecules in the crystal lattice. However, they share one common form once they are in solution form. Polymorphism is very important in those areas of chemical research where full characterization of a material has a pivotal role in determining its ultimate use e.g. in pharmaceutical, pigment, agrochemical, explosive and fine chemical industries. When polymorphism exists as a result of difference in crystal packing, it is called packing polymorphism. Polymorphism can also result from the existence of different conformers of the same molecule in conformational polymorphism. In pseudo polymorphism the different crystal types are the result of hydration or solvation. The types of different polymorphic forms are shown below: Fig: Types of different polymorphic forms Polymorphs seem to be more common for compounds with: * Low solubility in water * Organic salts * Formation of hydrates for larger molecules * Organic solvates –neutral compounds with larger molecular weights. * Compounds with molecular weight below 350 Pharmaceutical...
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...Lecture 1 Introduction to Semiconductor Devices Reading: Notes and Anderson2 Chapters 1.1-1.3, 1.7-1.9 Georgia Tech ECE 3080 - Dr. Alan Doolittle Atoms to Operational Amplifiers •The goal of this course is to teach the fundamentals of non-linear circuit elements including diodes, LEDs, LASER diodes, transistors (BJT and FET) , and advanced device concepts such as microwave compound semiconductors and state of the art devices. •Due to the diverse coverage from various professors for ECE3040, you will repeat (for some) some of the material from 3040. Specifically, you will learn about the fundamentals of electron movement in semiconductor materials and develop this basic knowledge of how we can construct devices from these materials that can control the flow of electrons and light in useful ways. Georgia Tech ECE 3080 - Dr. Alan Doolittle Market Study Silicon is and will for a very long time be the dominant material used for electronics. However, MANY up and coming materials are slowly eating into silicon’s dominance. Compound semiconductors Compound semiconductors Organic and compound semiconductors Georgia Tech ECE 3080 - Dr. Alan Doolittle Devices we will study Bold indicates devices covered in depth in ECE 3040 P-N diode, heterojunction diodes, ballistic diodes, Schottky barrier diodes, Metal-Semiconductor Contacts, LEDs, Lasers, Solar Cells, Photodetectors, BJT, HBT, MOSFET, MESFET, JFET, Polarization Based Devices (III-Nitrides HEMTs...
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...physical means. For example salt dissolved in water can be recovered by allowing the water to evaporate. A physical change involves a change in physical properties. Examples of physical properties include melting, transition to a gas, change of strength, change of durability, changes to crystal form, textural change, shape, size, colour, volume and density. An example of a physical change is the process of tempering steel to form a knife blade. A steel blank is repeatedly heated and hammered which changes the hardness of the steel, its flexibility and its ability to maintain a sharp edge. Methods Heating and cooling Many elements and some compounds change from solids to liquids and from liquids to gases when heated and the reverse when cooled. Some substances such as iodine and carbon dioxide go directly from solid to gas in a process called sublimation. Magnetism Ferro-magnetic materials can become magnetic. The process is reversible and does not affect the chemical composition. Crystallisation Many elements and compounds form crystals. Some such as carbon can form several different forms including diamond, graphite, graphene and fullerenes includingbuckminsterfullerene. Crystals in metals have a major effect of the physical...
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