196.5 kB
... with inorganic compounds many of which are optically active. Generally, the glycine crystals can be grown in the three different polymorphs: α -, β - and γ -glycine [3]. In Ref. [4], it was established that illumination of the water solution of such crystals may cause transformations from β to γ pha ...
... with inorganic compounds many of which are optically active. Generally, the glycine crystals can be grown in the three different polymorphs: α -, β - and γ -glycine [3]. In Ref. [4], it was established that illumination of the water solution of such crystals may cause transformations from β to γ pha ...
Atoms and Bonding
... In general, ionic compounds are hard, brittle crystals that have high melting points. When dissolved in water or melted, they conduct electricity. ...
... In general, ionic compounds are hard, brittle crystals that have high melting points. When dissolved in water or melted, they conduct electricity. ...
diamond springs dental center
... Methamphetamine in the hopes that it would shine some light on a problem that is so prevalent here in California. The fact is that most teachers, parents and dentists may not recognize the signs and symptoms of Crystal Meth abuse in their students/children/patients. This has become a hot topic here ...
... Methamphetamine in the hopes that it would shine some light on a problem that is so prevalent here in California. The fact is that most teachers, parents and dentists may not recognize the signs and symptoms of Crystal Meth abuse in their students/children/patients. This has become a hot topic here ...
Chapter 4: Imperfections in Solids Imperfections in Solids
... by the presence of imperfections. •It is important to have a knowledge about the types of imperfections that exist and the roles they play in affecting the behavior of materials. •The mechanical properties of pure metals experience significant changes when alloyed (i.e., when impurity atoms are adde ...
... by the presence of imperfections. •It is important to have a knowledge about the types of imperfections that exist and the roles they play in affecting the behavior of materials. •The mechanical properties of pure metals experience significant changes when alloyed (i.e., when impurity atoms are adde ...
powerpoint - Philip Hofmann
... The atomic structure of crystals cannot be determined by optical microscopy because the wavelength of the photons is much too long (400 nm or so). So one might want to build an x-ray microscope but this does not work for very small wavelength because there are no suitable x-ray optical lenses. The i ...
... The atomic structure of crystals cannot be determined by optical microscopy because the wavelength of the photons is much too long (400 nm or so). So one might want to build an x-ray microscope but this does not work for very small wavelength because there are no suitable x-ray optical lenses. The i ...
THE CRYSTAL STRUCTURE OF ALLOCHALCOSELITE, Cu
... selenite chloride of natural origin. In this paper, we report the details of its structure and compare it with that of related minerals and inorganic compounds. ...
... selenite chloride of natural origin. In this paper, we report the details of its structure and compare it with that of related minerals and inorganic compounds. ...
Crystal Structure of an Enzyme-Substrate Complex Provides Insight
... wild-type were eliminated from the model to calculate a sigmaA-weighted omit map,19 which shows the electron density corresponding to a pNCS molecule, with the sulfate group well de®ned and the aryl group discretely disordered over two sites, with relative occupancies of 60 and 40 %, respectively. T ...
... wild-type were eliminated from the model to calculate a sigmaA-weighted omit map,19 which shows the electron density corresponding to a pNCS molecule, with the sulfate group well de®ned and the aryl group discretely disordered over two sites, with relative occupancies of 60 and 40 %, respectively. T ...
Lecture 11 DFT for periodic crystalline solids CHEM6085: Density
... Example: band structure of crystalline silicon • The eigenvalues are called bands • Many properties of a material can be deducted from its band structure, which shows the as a function of k ...
... Example: band structure of crystalline silicon • The eigenvalues are called bands • Many properties of a material can be deducted from its band structure, which shows the as a function of k ...
Self-Assembly of the First Copper (II) Infinite 2D Network with Large
... (3)° while the methyl carbons, e.g. C7, C7A, C7B, etc., are in the plane of benzene ring to which they attached (Figure 1a). As shown in Figure 1a, the two benzene ring planes of the two titmb ligands with “up” and “down” orientations and the plane containing copper atoms Cu1, Cu1A, Cu1B, Cu1C, and ...
... (3)° while the methyl carbons, e.g. C7, C7A, C7B, etc., are in the plane of benzene ring to which they attached (Figure 1a). As shown in Figure 1a, the two benzene ring planes of the two titmb ligands with “up” and “down” orientations and the plane containing copper atoms Cu1, Cu1A, Cu1B, Cu1C, and ...
Peering into the Crystal Fabric of Rocks
... because I study the properties of rocks under stress and strain. Heat and stress causes chemical and physical alterations and defects in the crystal structure of rocks. Under stress, atoms are pushed against other atoms, sending further ripples of changes down the line, like people crowding in subwa ...
... because I study the properties of rocks under stress and strain. Heat and stress causes chemical and physical alterations and defects in the crystal structure of rocks. Under stress, atoms are pushed against other atoms, sending further ripples of changes down the line, like people crowding in subwa ...
April`s Mineral—Star Blue Quartz Alabama`s State Gemstone
... there are so many. There are also other states with quartz. With the approval of a bill proposed by Senator Don Hale, Cullman County, the star blue quartz was named the official gemstone for the State of Alabama by Act no. 90-203 in 1990. Most quartz is a souvenir of volcanoes, which melt silica, wh ...
... there are so many. There are also other states with quartz. With the approval of a bill proposed by Senator Don Hale, Cullman County, the star blue quartz was named the official gemstone for the State of Alabama by Act no. 90-203 in 1990. Most quartz is a souvenir of volcanoes, which melt silica, wh ...
The Role of Hydrogen Bond in Designing Molecular Optical Materials
... expansion. For the partition, one can use the quantum theory of atoms in molecules (QTAIM) [6], which is more generally applicable to a theoretical electron density as well. An advantage of QTAIM is that the partitioning is exact (meaning that the sum of atomic contributions exactly reconstruct the ...
... expansion. For the partition, one can use the quantum theory of atoms in molecules (QTAIM) [6], which is more generally applicable to a theoretical electron density as well. An advantage of QTAIM is that the partitioning is exact (meaning that the sum of atomic contributions exactly reconstruct the ...
Metastability limit for the nucleation of NaCl crystals in confinement
... Although recent simulations give us some more insight into the atomistic pathways of the nucleation of NaCl crystals (14,15), the current consensus appears to be that no high supersaturations can be reached for this salt, and that the pore size has a profound influence on the concentration at which ...
... Although recent simulations give us some more insight into the atomistic pathways of the nucleation of NaCl crystals (14,15), the current consensus appears to be that no high supersaturations can be reached for this salt, and that the pore size has a profound influence on the concentration at which ...
Structural studies of protein arginine methyltransferase 2 reveals its
... eukaryotic enzymes that catalyze the transfer of methyl groups from the methyl donor S-adenosyl-L-methionine (SAM) to guanidine nitrogens in arginine residues of target proteins. The PRMT family has been the focus of many biological researches and at least nine members of the PRMT family (PRMT1 to P ...
... eukaryotic enzymes that catalyze the transfer of methyl groups from the methyl donor S-adenosyl-L-methionine (SAM) to guanidine nitrogens in arginine residues of target proteins. The PRMT family has been the focus of many biological researches and at least nine members of the PRMT family (PRMT1 to P ...
Numerical Analysis of Fifth-Harmonic Conversion of Low
... 33 which is quite different from 45 . The reason for this can be explained as follows. In the crystal arrangement used in the generation process, the fourth harmonic generated from the cavity is horizontally polarized. The fifth harmonic is generated in a type I phase-matched BBO crystal by summing ...
... 33 which is quite different from 45 . The reason for this can be explained as follows. In the crystal arrangement used in the generation process, the fourth harmonic generated from the cavity is horizontally polarized. The fifth harmonic is generated in a type I phase-matched BBO crystal by summing ...
5 mm thick periodically poled Rb-doped KTP for high
... using the electric field poling technique. Due to the noncritical interaction in QPM media the parametric gain scales simply as a square of the crystal length, so that the relative differences in effective nonlinearities in different QPM materials can be easily compensated for by choosing an appropr ...
... using the electric field poling technique. Due to the noncritical interaction in QPM media the parametric gain scales simply as a square of the crystal length, so that the relative differences in effective nonlinearities in different QPM materials can be easily compensated for by choosing an appropr ...
full paper
... (Harbinger reasoning cosmographical or Cosmography mystery) in 1597. However, the most known achievement by Kepler is Kepler laws (1609), in particular his third law which connects the time of planet circulation with the planet distance from the Sun. After these two introductions, pass on the struct ...
... (Harbinger reasoning cosmographical or Cosmography mystery) in 1597. However, the most known achievement by Kepler is Kepler laws (1609), in particular his third law which connects the time of planet circulation with the planet distance from the Sun. After these two introductions, pass on the struct ...
Double-etch geometry for millimeter-wave photonic band
... unique properties of PBG materials were proposed.4 However, until recently the difficulties associated with the fabrication of smaller scale PBG structures (even at millimeter wave frequencies) had restricted the experimental demonstration of the basic PBG crystals to microwave frequencies (12-15 GH ...
... unique properties of PBG materials were proposed.4 However, until recently the difficulties associated with the fabrication of smaller scale PBG structures (even at millimeter wave frequencies) had restricted the experimental demonstration of the basic PBG crystals to microwave frequencies (12-15 GH ...
IOSR Journal of Applied Physics (IOSR-JAP)
... The degree of purity and perfection of crystals are to be known to interpret the structure dependent properties in order to determine whether the material can be successfully employed in the experiments or in the device fabrication process. It is also important to know the nature and distribution of ...
... The degree of purity and perfection of crystals are to be known to interpret the structure dependent properties in order to determine whether the material can be successfully employed in the experiments or in the device fabrication process. It is also important to know the nature and distribution of ...
SGES1273 Lab Handout 4
... can be found in the form of (solidified) mud (micrite), as clear, rhombohedral crystals filling veins and cracks, as stalactites and stalagmites in caves, and as the dense, massive rock with tiny crystals we know as marble. Carbonate minerals can be divided into two groups based on crystal symmetry. ...
... can be found in the form of (solidified) mud (micrite), as clear, rhombohedral crystals filling veins and cracks, as stalactites and stalagmites in caves, and as the dense, massive rock with tiny crystals we know as marble. Carbonate minerals can be divided into two groups based on crystal symmetry. ...
Spontaneous emission spectra of organic molecules in synthetic
... The fluorescence spectra of the R6G and BBHQ molecules are shown in Fig. 2. As seen from Fig. 2a, a suppression of the fluorescence intensity inside the region of 565–600 nm and a “blue” shift of short-wavelength tail of the spectrum by 10 nm take place for the R6G molecules embedded in the SOPC (se ...
... The fluorescence spectra of the R6G and BBHQ molecules are shown in Fig. 2. As seen from Fig. 2a, a suppression of the fluorescence intensity inside the region of 565–600 nm and a “blue” shift of short-wavelength tail of the spectrum by 10 nm take place for the R6G molecules embedded in the SOPC (se ...
3-nitroaniline and 3-nitrophenol – A novel non linear optical material
... investigated crystal there exists an additional possibility to enhance their non-linear optical properties by applying of external fields, for example polarized light which may form additional alignment of the crystals. At the same time one can expect substantial anisotropy of the obtained dependenc ...
... investigated crystal there exists an additional possibility to enhance their non-linear optical properties by applying of external fields, for example polarized light which may form additional alignment of the crystals. At the same time one can expect substantial anisotropy of the obtained dependenc ...
X-ray crystallography
X-ray crystallography is a tool used for identifying the atomic and molecular structure of a crystal, in which the crystalline atoms cause a beam of incident X-rays to diffract into many specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their disorder and various other information.Since many materials can form crystals—such as salts, metals, minerals, semiconductors, as well as various inorganic, organic and biological molecules—X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences among various materials, especially minerals and alloys. The method also revealed the structure and function of many biological molecules, including vitamins, drugs, proteins and nucleic acids such as DNA. X-ray crystallography is still the chief method for characterizing the atomic structure of new materials and in discerning materials that appear similar by other experiments. X-ray crystal structures can also account for unusual electronic or elastic properties of a material, shed light on chemical interactions and processes, or serve as the basis for designing pharmaceuticals against diseases.In a single-crystal X-ray diffraction measurement, a crystal is mounted on a goniometer. The goniometer is used to position the crystal at selected orientations. The crystal is bombarded with a finely focused monochromatic beam of X-rays, producing a diffraction pattern of regularly spaced spots known as reflections. The two-dimensional images taken at different rotations are converted into a three-dimensional model of the density of electrons within the crystal using the mathematical method of Fourier transforms, combined with chemical data known for the sample. Poor resolution (fuzziness) or even errors may result if the crystals are too small, or not uniform enough in their internal makeup.X-ray crystallography is related to several other methods for determining atomic structures. Similar diffraction patterns can be produced by scattering electrons or neutrons, which are likewise interpreted by Fourier transformation. If single crystals of sufficient size cannot be obtained, various other X-ray methods can be applied to obtain less detailed information; such methods include fiber diffraction, powder diffraction and (if the sample is not crystallized) small-angle X-ray scattering (SAXS).If the material under investigation is only available in the form of nanocrystalline powders or suffers from poor crystallinity, the methods of electron crystallography can be applied for determining the atomic structure.For all above mentioned X-ray diffraction methods, the scattering is elastic; the scattered X-rays have the same wavelength as the incoming X-ray. By contrast, inelastic X-ray scattering methods are useful in studying excitations of the sample, rather than the distribution of its atoms.