Crystal Technology. Basic Technology of Quartz Crystal Resonators Quartz crystal resonators (often called “crystals”) are widely used in frequency control applications because of their unequalled combination of high Q, stability, small size and low cost. Many different substances have been investigated as possible resonator materials, but for many years quartz resonators have been preferred in satisfying needs for precise frequency control. Compared to other resonators, for example, LC circuits, mechanical resonators such as tuning forks, and piezoelectric ceramic resonators based or other single-crystal materials, the quartz resonator has a unique combination of properties.
First, the material properties of single-crystal quartz are extremely stable with time, temperature, and other environmental changes, as well as highly repeatable from one specimen to another. The second key property of the quartz resonator is its stability with respect to temperature variation. Quartz Plate Orientation Vibration Modes. Quartz crystals :: technical data from International Crystal. Home > Crystal Products > Quartz Crystals > Technical Data > Crystal Data Before beginning a design or purchase of a crystal there are system parameters, which must be considered.
Below are questions, which need to be determined by your system. These parameters will determine the crystal specifications. On what crystal frequency do you wish to operate? How much can the frequency be off at room temperature (+25°C)? What is the temperature range over which the crystal will operate? How much can the crystal change frequency over the temperature range? The Quartz Crystal The quartz crystal may be represented by the L, C, R circuit (below). C0 is the capacitance formed by the crystal electrodes plus any holder capacitance.
Knowing two different loads on the crystal, we can look at the differences between each shift from series to calculate total trim range. C1 and R1 can be specified on any crystal. Frequency The quartz crystal can be made on frequencies between 70 kHz and 200 MHz. World's Most Efficient Insulation Made From Synthetic Crystal Could Keep Satellites Pinging From Deepest Space. Deep-space probes and scientific devices in Antarctica could soon get a new form of insulation based on synthetic crystals that stop and reflect heat. Such material could eventually lead to the best insulation ever created, even at room temperatures. The crystals work by manipulating phonons, or vibrational waves that can carry either sound or heat depending on the frequency. Each crystal structure consists of alternating layers of silicon dioxide and a polymer material, so that the spacing between similar layers matches the wavelength of phonons.
That allows the material to block and reflect back the phonons in the form of heat. Most prior research used larger crystals to deal with sound-related phonons, but nanotechnology has given researchers the ability to create the tiny structures necessary to control heat-related phonons. Phonons reflected by the new material represent low-frequency heat, and so the material only does its insulating trick in sub-freezing temperatures. Liquid crystals light way to better data storage. As cell phones and computers continue to shrink, many companies are seeking better ways to store hundreds of gigabytes of data in small, low-power devices.
A special type of liquid crystal, similar to those used in computer displays and televisions, offers a solution. Unlike CDs and DVDs, which store information only on their surface, lasers can encode data throughout a liquid crystal. Known as holographic storage, the technique makes it possible to pack much more information in a tiny space. But attempts to use liquid crystals for data storage have had limited success. In order to reliably record and rewrite data, researchers must figure out a way to uniformly control the orientation of liquid crystal molecules. In an important advance, scientists at the Tokyo Institute of Technology have created a stable, rewritable memory device that exploits a liquid crystal property called the "anchoring transition. " 'Green energy' advance: Tandem catalysis in nanocrystal interfaces. In a development that holds intriguing possibilities for the future of industrial catalysis, as well as for such promising clean green energy technologies as artificial photosynthesis, researchers with the U.S.
Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have created bilayered nanocrystals of a metal-metal oxide that are the first to feature multiple catalytic sites on nanocrystal interfaces. These multiple catalytic sites allow for multiple, sequential catalytic reactions to be carried out selectively and in tandem. Yang is the corresponding author of a paper describing this research that appears in the journal Nature Chemistry. Co-authoring the paper were Yusuke Yamada, Chia-Kuang Tsung, Wenyu Huang, Ziyang Huo, Susan Habas, Tetsuro Soejima, Cesar Aliaga and leading authority on catalysis Gabor Somorjai. "The cubic shape of the nanocrystal layers is ideal for assembling metal-metal oxide interfaces with large contact areas," Yang says.
Pyroelectric Crystals Could Enable the First Truly Portable X-Ray Machine. Like many pieces of modern medical equipment, X-ray machines are as bulky and energy dependent as they are vital. Even "portable" X-ray machines remain too heavy to carry across rough terrain, and too energy hungry to run off batteries. That's why Radius Health's portable, low energy X-ray machine may revolutionize medicine in disaster zones, on the front lines, and at patients homes. By using pyroelectric crystals as an X-ray source, Radius Health has created a machine small enough to fit in a suitcase, light enough to deploy anywhere, and energy efficient enough to run on a laptop battery.
The secret to Radius Health's device is the pyroelectric crystals. Borrowed from semiconductor technology, the crystals emit electromagnetic radiation when heated. Additionally, by using an array of crystal points, instead of the single, large X-ray source used in conventional machines, the Radius Health device can produce a usable image with a far lower dose of radiation. [Technology Review] Using Special Crystals, Researchers Make a Paper Clip Invisible. Metamaterials have long been thought the key to creating the working, visible spectrum "invisibility cloak" promised us by sci-fi, but it might be time for metamaterials to move over. Two independent labs—one at the University of Birmingham in the UK, the other at MIT—have used naturally forming calcite crystals to render visible objects (as in large enough to see with the naked eye) invisible, something metamaterials haven't come close to doing.
Metamaterials have achieved a measure of invisibility, but not in any practical sense; they can bend certain wavelengths of light to conceal an object at the microscopic level, but so far they have not been able to work well at the macro scale or in the visible spectrum. It turns out researchers may not have needed such an exotic medium. For now, the technology is nascent and somewhat two-dimensional, though the MIT team says it has some ideas regarding how they could make the cloaking three-dimensional. [Telegraph, MIT News] Upgrading Your Quantum Memory? Don't Forget the Crystals. Quantum communication offers myriad advantages over conventional fiber optic networking, but manipulating electrons or photons to behave in the proper fashion has long kept quantum networking a "theoretical" pursuit. But University of Calgary researchers working with German colleagues at the University of Paderborn have pushed quantum networks a big step closer to reality by demonstrating that specially doped crystals can store and retrieve information encoded in entangled photons.
In other words, they've created a form of quantum memory. Like fiber optic networks, information traveling through quantum networks via entangled particles needs somewhere to live – something akin to computer memory – in order for complex computations to take place or sophisticated networks to be created. This isn't easy, as the entangled link between two particles is fragile – tamper with it too much, and the link can be fouled. [Eurekalert] 'Ancestral Eve' crystal may explain origin of life's left-handedness. Scientists are reporting discovery of what may be the "ancestral Eve" crystal that billions of years ago gave life on Earth its curious and exclusive preference for so-called left-handed amino acids. Those building blocks of proteins come in two forms -- left- and right-handed -- that mirror each other like a pair of hands. Their study, which may help resolve one of the most perplexing mysteries about the origin of life, is in ACS' Crystal Growth & Design, a bi-monthly journal.
Tu Lee and Yu Kun Lin point out that conditions on the primordial Earth held an equal chance of forming the same amounts of left-handed and right-handed amino acids. Nevertheless, when the first forms of life emerged more than 3 billion years ago, all the amino acids in the proteins had the left-handed configuration. That pattern continued right up to modern plants and animals. Chemist develops technique to use light to predict molecular crystal structures. A Syracuse University chemist has developed a way to use very low frequency light waves to study the weak forces (London dispersion forces) that hold molecules together in a crystal.
This fundamental research could be applied to solve critical problems in drug research, manufacturing and quality control. The research by Timothy Korter, associate professor of chemistry in SU's College of Arts and Sciences, was the cover article of the March 14 issue of Physical Chemistry Chemical Physics. "When developing a drug, it is important that we uncover all of the possible ways the molecules can pack together to form a crystal," Korter says. "Changes in the crystal structure can change the way the drug is absorbed and accessed by the body. " One industry example is that of a drug distributed in the form of a gel capsule that crystallized into a solid when left on the shelf for an extended period of time, Korter explains. Chemists grow crystals with a twist -- and untwist. Chemists from New York University and Russia's St. Petersburg State University have created crystals that can twist and untwist, pointing to a much more varied process of crystal growth than previously thought.
Their work, which appears in the latest issue of the Journal of the American Chemical Society, may explain some of the properties of high-polymers, which are used in clothing and liquid crystal displays, among other consumer products. Crystal growth has traditionally been viewed as a collection of individual atoms, molecules, or small clusters adding to a larger block that remains in a fixed translational relationship to the rest. But the NYU and St. Petersburg State University chemists discovered a wholly new phenomenon for growth -- a crystal that continually changes its shape as it grows.
To do this, the researchers focused on crystals from hippuric acid -- a derivative of the amino acid glycine. Quartz crystal microbalance. General[edit] The frequency of oscillation of the quartz crystal is partially dependent on the thickness of the crystal. During normal operation, all the other influencing variables remain constant; thus a change in thickness correlates directly to a change in frequency. As mass is deposited on the surface of the crystal, the thickness increases; consequently the frequency of oscillation decreases from the initial value. With some simplifying assumptions, this frequency change can be quantified and correlated precisely to the mass change using Sauerbrey's equation.[2] Other techniques for measuring the properties of thin films include Ellipsometry, Surface Plasmon Resonance (SPR) Spectroscopy, and Dual Polarisation Interferometry.
Gravimetric and non-gravimetric QCM[edit] The classical sensing application of quartz crystal resonators is microgravimetry.[3][4][5][6] Many commercial instruments, some of which are called thickness monitors, are available. Instrumental[edit] Overtones[edit] Crystal oscillator. Quartz crystal resonator (left) and quartz crystal oscillator (right) A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency.[1][2][3] This frequency is commonly used to keep track of time (as in quartz wristwatches), to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers.
The most common type of piezoelectric resonator used is the quartz crystal, so oscillator circuits incorporating them became known as crystal oscillators,[1] but other piezoelectric materials including polycrystalline ceramics are used in similar circuits. Quartz crystals are manufactured for frequencies from a few tens of kilohertz to hundreds of megahertz. More than two billion crystals are manufactured annually. History[edit] Very early Bell Labs crystals from Vectron International Collection or,