Different Kinds Of Crystals Research Articles

Composition based crystal materials symmetry prediction using machine learning with enhanced descriptors

Geometric information such as the space groups and crystal systems plays an important role in the properties of crystal materials. Prediction of crystal system and space group thus has wide applications in crystal material property estimation and structure prediction. Previous works on experimental X-ray diffraction (XRD) and density functional theory (DFT) based structure determination methods achieved outstanding performance, but they are not applicable for large-scale screening of materials compositions. There are also machine learning models using Magpie descriptors for composition based material space group determination, but their prediction accuracy only ranges between 0.638 and 0.907 in different kinds of crystals. Herein, we report an improved machine learning model for predicting the crystal system and space group of inorganic materials using only the formula information. Benchmark study on a dataset downloaded from Materials Project Database shows that our random forest models based on our new descriptor set, achieve significant performance improvements compared with previous work with accuracy scores ranging between 0.712 and 0.961 in terms of space group classification. Our model also shows large performance improvement for crystal system prediction. Trained models and source code are freely available athttps://github.com/Yuxinya/SG_predict

Influence of phosphate chelators on white efflorescence formation in dry fermented sausages with co-extruded alginate casings

The aim of the study was to investigate the effect of different condensed phosphates on the white efflorescence formation on dry fermented sausages with calcium alginate casings. The efflorescence formation is induced by the complexation of the divalent cations magnesium and calcium with lactate on the surface of the product. Phosphates are known to complex divalent cations like magnesium and calcium, which are responsible for the efflorescence formation with lactate. To treat the surface of the raw fermented sausages a mixture of di- and polyphosphates and a polyphosphate were used. The sausages were dipped in 5% solutions of the phosphates. The mixture of di- and polyphosphate showed the best results in reducing the white efflorescence formation, the amount of efflorescences on the surface was 18.12% after 8 weeks of storage. The diffusion of magnesium was significantly reduced by ~40% after 8 weeks of storage compared to the control for both phosphates. However, the crystals formed during storage had a different structure and size compared to the control. Isothermal titration calorimetry measurements showed that the divalent calcium ions and the polyphosphates from aggregates caused the crystal formation on the surface, whereas this effect was not seen in combination with magnesium. The surface treatment with the phosphates did not inhibit the white efflorescence formation. However, the extent was reduced but different kind of crystals were formed on the surface during the storage.

Stimuli-Responsive Aggregation-Induced Delayed Fluorescence Emitters Featuring the Asymmetric D-A Structure with a Novel Diarylketone Acceptor Toward Efficient OLEDs with Negligible Efficiency Roll-Off.

Multifunctional luminescent materials with aggregation-induced delayed fluorescence (AIDF) are capable of suppressing concentration-caused emission quenching and exciton annihilation when used as organic light-emitting diode (OLED) emitters. In this contribution, three stimuli-responsive AIDF luminogens, pipd-BZ-PXZ, pipd-BZ-PTZ, and pipd-BZ-DMAC, featuring a D-A asymmetric framework based on a fused N-heterocycle diarylketone acceptor (imid-azo[1,2-a]pyridin-2-yl(phenyl)methanone pipd) are designed and synthesized. Interestingly, pipd-BZ-PTZ forms two different kinds of crystals (G-crystal and O-crystal) with distinct intermolecular interactions between pipd moieties. The G-crystal with a looser packing mode presents significant morphology-dependent stimuli-responsive behavior with a shifted emission wavelength of 56 nm. Generated by a strong intramolecular charge transfer effect, pipd-BZ-PXZ and pipd-BZ-PTZ exhibit orange to red emission in solution and neat films. Both nondoped and doped devices are fabricated for comparison. Nondoped devices present moderate performance with external quantum efficiencies and current efficiency that reach 7.04% and 19.86 cd A-1, respectively, and the corresponding efficiency roll off at 1000 cd m-2 is as small as 2.3%, which is among the best records of AIDF-OLEDs with an emission wavelength over 570 nm. Doped devices show better performance with corresponding efficiencies of up to 55.41 cd A-1 and 15.77%.

Bulk crystal growth and characterization of 2.5–5.0 µm mid-infrared laser crystals

Mid-infrared waveband lasers have demonstrated important applications in the fields of atmosphere pollution monitoring, gas flow monitoring, ocean detection, laser medicine, military confrontation and basic scientific researches etc. In this paper, we review the research development of bulk crystal growth, physicochemical, spectral and laser properties of 2.5–5.0 μm waveband mid-infrared laser crystals in recent years. A serial of gallate and aluminate crystals with low phonon energy were grown by the Czochralski method, such as Er3+ activated and rare earth ions co-doped Gd3Ga5O12(GGG), SrGdGa3O7, SrLaGa3O7, CaYAlO4 and CaGdAlO4 crystals, Ho3+ activated and rare earth ions co-doped GGG crystals, as well as Dy3+:YAlO3 crystals, and 2.5–3.4 μm waveband emissions were obtained in these crystals. High quality Dy3+:KPb2Cl5, Cr2+:CdSe and Cr2+:Fe2+:CdSe crystals were grown by the Bridgman method, and 2.5–5.0 μm waveband emissions were obtained in these crystals. The physicochemical and spectral properties of the above crystals were studied systematically, with focus on analyses of the concentration effect of activated ions Er3+, the sensitization mechanism of the co-dopant sensitized ions and the impact of the depopulated ions on the inhibition of self-termination effect. The fluorescence dynamic of the activated ions within the mid-infrared waveband, the energy transfer efficiencies between activated ions and co-dopant sensitization ions, as well as between the activated ions and co-dopant depopulation ions were calculated, and the energy transfer mechanism was discussed. Based on the results of spectroscopic investigations, the concentrations of Er3+, the types and the concentrations the co-dopant sensitization ions were optimized in different kinds of crystals. The laser properties of Er3+ activated GGG, CaYAlO4 crystals were presented. Finally, 2.7–2.8 µm multi-wavelength CW or pulsed lasers were achieved in Er:GGG, Er,Pr:GGG and Er:GGG/GGG composite crystals end-pumped by 965 nm LD or in Cr,Er:YSGG crystals by Xenon lamp, furthermore, the single longitudinal mode microchip laser was achieved in Er:GGG crystal for the first time.

Chiral scrambling and independent crystallization of D4, L4, and D2L2 isomers of an Au(I)4Co(III)2 hexanuclear complex with mixed penicillaminate and bis(diphenylphosphino)ethane.

The 1:1 mixing of a pair of enantiomers of a cyclic Au(I)4Co(III)2 hexanuclear complex having penicillaminate (pen) and 1,2-bis(diphenylphosphino)ethane (dppe), [Au4Co2(dppe)2(d-pen)4](2+) (d4-[1](2+)) and [Au4Co2(dppe)2(l-pen)4](2+) (l4-[1](2+)), in solution produced an additional stereoisomer, [Au4Co2(dppe)2(d-pen)2(l-pen)2](2+) (d2l2-[1](2+)), because of the scrambling of [Co(d-pen)2](-) and [Co(l-pen)2](-) units between d4-[1](2+) and l4-[1](2+). Upon crystallization with NO3(-), the three stereoisomers were independently crystallized to form three different kinds of crystals, homochiral crystals of d4-[1](NO3)2, homochiral crystals of l4-[1](NO3)2, and heterochiral crystals of d2l2-[1](NO3)2, showing a unique example of the self-recognition and organization of three stereoisomers upon crystallization.

A new class of cuprous bromide cluster-based hybrid materials: direct observation of the stepwise replacement of hydrogen bonds by coordination bonds.

Although a variety of functional metal-organic frameworks (MOFs) have been synthesized, post-modified, and applied in various areas, there is little knowledge about how molecular cluster building units are stepwise evolved into MOFs via intermediates. Coordination bonds are generally stronger than hydrogen bonds, and thus equivalent replacement of X-H···Y hydrogen bonds by X-M-Y coordination bonds can transform hydrogen bond networks into MOFs. In this work, solvothermal in situ reduction reactions of CuBr2 and 1,4-diazoniabicyclo[2,2,2]octane (DABCO) generated a myriad of tunable photoluminescent cuprous body-centered cubic bromide cluster-based networks with the general formula [Cu4+xH4-xBr6(DABCO)4](HCO2)2·S (x = 0, 0.56, 0.81, 1.27, 1.39, 2.56, 2.78, and 4 for compounds 1-8, respectively). All of these compounds crystallize in the cubic space group with the largest volume difference being only 5.2%, but they belong to three remarkably different kinds of crystals. Complex 1 is a molecular crystal and consists of tetrahedral [Cu4Br6(HDABCO)4](2+) clusters with monodentate HDABCO groups that are supported via N-H···Br synthons in the hydrogen bond network. Compound 8 is a [Cu8Br6](2+) cube cluster-based MOF with bridged DABCO ligands. Complexes 2-7 are seemingly impossible Cu/H-substituted solid solutions of 1 and 8. The CuBr framework components in 1-8 are Cu4Br6, Cu4.56Br6, Cu4.81Br6, Cu5.27Br6, Cu5.39Br6, Cu6.56Br6, Cu6.78Br6, and Cu8Br6, respectively. Crystallization kinetics studies revealed that the [Cu4Br6(HDABCO)4](2+) cluster-based hydrogen bond network (1) was initially formed such that N-H···Br hydrogen bonds could be stepwise replaced by N-Cu-Br coordination bonds to form the [Cu8Br6](2+) cube cluster-based MOF (8) via solid solutions. These observations directly reveal the equivalence and transformation between the N-H···Br hydrogen bond and the N-Cu-Br coordination bond and the evolutionary mechanism of a molecular crystal to a MOF via solid solutions, which is of fundamental importance in materials but has never before been revealed. DFT calculations suggest that equivalent replacement of a N-H···Br hydrogen bond by a N-Cu-Br coordination bond is exothermic and exergonic, which also supports the transformation from molecule 1 to MOF 8.

Low temperature and high pressure crystals of room temperature ionic liquid: N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate

Crystals of room temperature ionic liquid (RTIL) are obtained separately at low temperature or under high pressure. The RTIL is N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate, [DEME][BF4]. At ambient pressure, low-temperature (LT) crystals appeared on slow cooling. By simultaneous X-ray diffraction and differential scanning calorimetry (DSC) measurements, metastable monoclinic and stable orthorhombic phases coexist in pure [DEME][BF4]. Furthermore, the DSC thermal trace indicates that the metastable monoclinic phase was stabilized by adding water. In contrast, on compression process up to 7.6 GPa, crystallization is completely suppressed even upon slow compression. Direct observations using optical microscopy also support no crystal domain growth on compression process. High-pressure (HP) crystals at room temperature were seen only on decompression process, where two different kinds of crystals appeared subsequently. By crystal structure analysis, the LT crystal structures have no relation with the HP ones. Moreover, both metastable monoclinic phase at low temperature and higher pressure crystal has a folding molecular conformation and anti-parallel pairing of the [DEME] cation as the instability factors.

Competing Crystal Phases in the Lowest Landau Level

We show that the solid phase between the 1/5 and 2/9 fractional quantum Hall states arises from an extremely delicate interplay between type-1 and type-2 composite fermion crystals, clearly demonstrating its nontrivial, strongly correlated character. We also compute the phase diagram of various crystals occurring over a wide range of filling factors and demonstrate that the elastic constants exhibit nonmonotonic behavior as a function of the filling factor, possibly leading to distinctive experimental signatures that can help mark the phase boundaries separating different kinds of crystals.

The story of Earth: the first 4.5 billion years, from stardust to living planet

Earth evolves. From first atom to molecule, mineral to magma, granite crust to single cell to verdant living landscape, ours is a planet constantly in flux. In this radical new approach to EarthÐ2Ђ™s biography, senior Carnegie Institution researcher and national bestselling author Robert M. Hazen reveals how the co-evolution of the geosphere and biosphereÐ2Ђ―of rocks and living matterÐ2Ђ―has shaped our planet into the only one of its kind in the Solar System, if not the entire cosmos. With an astrobiologistÐ2Ђ™s imagination, a historianÐ2Ђ™s perspective, and a naturalistÐ2Ђ™s passion for the ground beneath our feet, Hazen explains how changes on an atomic level translate into dramatic shifts in EarthÐ2Ђ™s makeup over its 4.567 billion year existence. He calls upon a flurry of recent discoveries to portray our planetÐ2Ђ™s many iterations in vivid detailÐ2Ђ―from its fast-rotating infancy when the Sun rose every five hours and the Moon filled 250 times more sky than it does now, to its sea-bathed youth before the first continents arose; from the Great Oxidation Event that turned the land red, to the globe-altering volcanism that may have been the true killer of the dinosaurs. Through HazenÐ2Ђ™s theory of Ð2ЂNsco-evolution,Ð2ЂNœ we learn how reactions between organic molecules and rock crystals may have generated EarthÐ2Ђ™s first organisms, which in turn are responsible for more than two-thirds of the mineral varieties on the planetÐ2Ђ―thousands of different kinds of crystals that could not exist in a nonliving world. The Story of Earth is also the story of the pioneering men and women behind the sciences. Readers will meet black-market meteorite hawkers of the Sahara Desert, the gun-toting Feds who guarded the Apollo missionsÐ2Ђ™ lunar dust, and the World War II Navy officer whose super-pressurized Ð2ЂNsbombÐ2ЂNœÐ2Ђ―recycled from military hardwareÐ2Ђ―first simulated the molten rock of EarthÐ2Ђ™s mantle. As a mentor to a new generation of scientists, Hazen introduces the intrepid young explorers whose dispatches from EarthÐ2Ђ™s harshest landscapes will revolutionize geology. Celebrated by the New York Times for writing Ð2ЂNswith wonderful clarity about science . . . that effortlessly teaches as it zips along,Ð2ЂNœ Hazen proves a brilliant and entertaining guide on this grand tour of our planet inside and out. Lucid, controversial, and intellectually bracing, The Story of Earth is popular science of the highest order. Ð’Â

Theoretical study of interaction of the acoustic waves in different crystals

In isotropic solids, transverse acoustic waves propagate undistorted and the interaction of collinear transverse waves is forbidden. In this study, It is found that transverse and longitude waves behave differently in anisotropic solids and the different formulas are given for the interaction of transverse and longitude acoustic waves propagating in different kinds of crystals including cubic, trigonal, tetragonal, hexagonal crystals. The formulas are expressed in terms of the derivatives of the strain energy. The formulas are used to calculate the interaction coefficients in the general anisotropic medium emphasizing the influence of nonlinearities. The evolution equations are derived for the wave amplitudes and find analytical formulas for all interaction coefficients of quadratically nonlinear interacting waves. The equations of motion show that transverse and longitude waves are distort as they propagate and interact. It is observed that two acoustic waves with frequency can produce harmonic waves with sum and difference frequency. This shows evidence that the intrinsic nonlinearities of an anisotropic solid can induce an interaction of acoustic waves. This project is supported the National Basic Research Program of China (Grant Nos. 2012CB921504, 2011CB707902), financial support of the National Natural Science Foundation of China (Grant No. 11074122), fundamental Research Funds for the Central Universities (Grant Nos. 1113020403, 1101020402), State Key Laboratory of Acoustics, Chinese Academy of China (Grant No. SKLOA201005) and A project funded by the priority academic program development of Jiangsu higher education institutions.

Reactivity and Composition of Dispersed Ni Catalyst for Slurry-Phase Residue Hydrocracking

The composition and reactivity of dispersed Ni catalyst was studied for slurry-phase hydrocracking of the residue. The Ni catalyst was separated at different reaction times and characterized. It was concluded that the water-soluble salts turned into NiS and Ni3S2 after the reaction for 1 or 2 h, respectively. After 3 h of reaction, the crystal of Ni9S8 appeared in the catalyst, and after 4 h of reaction, the catalyst was mainly made up of Ni9S8. The “relative coke restraining ratio” (Cr) was introduced and used to show the coke restraining ability of Ni catalysts at different reaction times. It was concluded that the coke restraining ability of the catalyst containing different kinds of crystals was different. To acquire a higher coke restraining ability of the catalyst, the proper reaction time of residue hydrocracking with dispersed Ni catalyst is 1.0−2.0 h.

In Situ FTIR Studies on the Cold-Crystallization Process and Multiple Melting Behavior of Isotactic Polystyrene

The structure evolution of iPS during isothermal cold-crystallization and subsequent melting processes is studied by in situ monitoring its FTIR spectra. Through following the intensity changes of the characteristic bands associated with its crystalline status and 31 helix conformation chains, the multiple melting behavior of iPS cold-crystallized at different temperatures has been discussed in detail. It is concluded that (i) the lowest-temperature annealing peak can be ascribed either to the relaxing of locally ordered long 31 helix chains in the amorphous phase or to the melting of some microcrystallites formed upon long-time annealing; (ii) the double melting behavior of iPS cold-crystallized at temperatures lower than 180 °C is mainly attributed to the model of melting, recrystallization, and remelting of the iPS crystals; and (iii) for the sample cold-crystallized at a temperature of 200 °C, the in situ IR experiments give strong evidence to support the existence of different kinds of crystals which...

Absolute asymmetric photocyclization of a photochromic diarylethene derivative in single crystals.

Chirality from the crystal lattice: The achiral diarylethene 1 a crystallizes in a monoclinic chiral space group, that is, two different kinds of crystals, (M)-1 a and (P)-1 a, are obtained. Photoirradiation of (P)-1 a furnished optically pure closed-ring isomer (R,R)-1 b in the single crystal (see scheme). The photochemical cycles can be repeated by alternating UV and visible photoirradiation. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2003/z50417_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Surface induced crystallization of PCL on oriented PE substrates: epitaxy and transcrystallization

The crystallization behavior of polycaprolactone (PCL) on the highly oriented polyethylene (PE) substrates was studied by means of optical microscopy (OM), transmission electron microscopy (TEM), and electron diffraction (ED). The results of both OM and TEM observations indicate that PE is a very active nucleation agent for PCL. While a transcrystalline zone of PCL is observed in the boundary area of the PE substrate by optical microscopy, both heteroepitaxy and transcrystallization of PCL on the PE substrates are recognized by TEM observations. It was further found that the transcrystalline zone of PCL in the thin films is composed of two different kinds of crystals, i. e. the edge-on crystalline lamellae at the interface, and the further grown flat-on crystals. In thicker samples, a semi-period lamellar twisting occurs during growth of the transcrystalline crystals.

Coordination polymers incorporating light lanthanide ions

The reaction, in a gel medium, of Sm(III) chloride with the trisodium salt of benzene-1,3,5-tricarboxylic acid (H 3TMA) yielded three different kinds of crystals. All three have been structurally characterized. 1, namely SmTMA(H 2O) 6 crystallizes in Cc with a=11.4818(12) Å, b=18.062(2) Å, c=7.219(1) Å, β=118.5432(11)° and Z=4. Its crystal structure has been found to be isostructural to the Y(III) complex already reported. It consists of juxtaposed ribbon-like molecular motifs. 2, namely SmTMA(H 2O) 5·H 2O has been found to be isostructural to the Er(III) complex already reported. It crystallizes in P-1 with a=7.6305(15) Å, b=9.9654(15) Å, c=11.219(2) Å, α=106.98°, β=103.52(2)°, γ=107.50(2)° and Z=2. Its structure consists of juxtaposed chains. 3, namely Er 3TMA 3(H 2O) 3·1.5H 2O crystallizes in C2/ c with a=20.511(2) Å, b=10.020(1) Å, c=15.294(2) Å, β=125.53(1) and Z=8. Its structure consists of parallel double-sheet networks based on honeycomb-like motifs. Heating 1 liberates water molecules and finally leads to SmTMA, namely 4, which can reversibly bind water reforming 1.

A new family of Er(III) complexes: from chains to nanotubes

The reaction, in a gel medium, of Er(III) chloride with the trisodium salt of benzene-1,3,5-tricarboxylic acid (H 3TMA) yielded three different kind of crystals. All three have been structurally characterized. ErTMA(H 2O) 5·3.5H 2O ( 1) crystallizes in C2/ c with a=14.7396(15), b=16.9874(15), c=14.4591(14) Å, β=118.754(9)° and Z=8. Its crystal structure has been reported elsewhere already. It consists of juxtaposed criss–cross chains. ErTMA(H 2O) 3·1.5H 2O ( 2) has been found to be isostructural to the Gd(III) complex reported already. It crystallizes in C2/ c with a=20.452(2), b=9.973(1), c=15.251(1) Å, β=125.68° and Z=8. Its structure consists of parallel double-sheet networks based on honeycomb-like motifs. Er 3TMA 3(H 2O) 8·4H 2O ( 3) crystallizes in P1̄ with a=9.988(2), b=15.656(3), c=19.698(3) Å, α=110.77(2), β=100.63(2), γ=100.58(2)° and Z=2. Its structure consists of parallel tube like layers based on the honeycomb-like molecular motifs already observed in 2. The crystal structure is reported herein. A predominant phase diagram has been established versus the concentrations of the gel medium and of the solutions. Heating one of them progressively liberates water molecules, which finally leads to ErTMA ( 4), which can reversibly bind water reforming 1.

Use Of A Capillary X-Ray Focused Beam To Investigate The Chemical Composition Of CdZnTe Wafers With High Resolution CdZnTe Detectors

AbstractThe control of the concentration of Zn and its fluctuation in the high pressure Bridgman grown CdZnTe crystals is part of our characterization work on the ternary grown ingots grown in house. In order to reach both high sensitivity and high position resolution, we have developed a new system consisting of a X-ray generator, coupled to a focusing X-ray capillary, delivering intense beams in the micron scale, since the intensity gain is around a factor of 100 compared to conventional methods.The characteristic X-rays are measured through a high resolution CdZnTe detector (225 eV at 5.9 keV FWHM) cooled by a Peltier system. The results of our investigations on different kinds of crystals will be discussed.

ON THE SIZE DISTRIBUTION OF FRAGMENTS GENERATED BY CRYSTAL COLLISIONS

Abstract The present work reports the results of so called “impact experiments” on nine different kinds of crystals, five inorganic salts and four organic acids, performed by letting ten crystals fall through an evacuated tube onto a glass plate. The ratio between the abraded volume of a crystal and the volume of the crystal itself is inversely proportional to the plasticity index of the material. The size distribution of the fragments, in terms of number density function vs. size, is well fitted for all the systems by a power law equation with an order equal to - 2.82 For one of the system examined, potassium sulphate, the size distributions of fragments obtained by the impact experiments have been successfully compared with those of the fines produced during batch seeded crystallizations carried out at low supersaturations. It therefore appears that the size distribution of the fragments generated by crystal attrition in a crystallizer may be generally predicted by means of the proposed power law equation.

Relaxation of diffusion stresses in a contact during sintering of various crystals

Specific dislocation structures and cracks formed near a contact during sintering of different kinds of crystals have been observed. Stress field interaction in groups of particles was considered.

Reaction of Mo 2(O 2CME) 2Cl 2(dppe) with pyridine; structural characterizations of the products of Mo 2Cl 2(OAc) 2Py 2 and MoOCl 2(dppe)(Py)

By layering a CH 2Cl 2/pyridine solution of Mo 2Cl 2(OAc) 2(dppe) with n-hexane, two different kinds of crystals were obtained, both of which were characterized by X-ray crystallography. Crystal data for Mo 2Cl 2(OAc) 2Py 2 ( 1): P 1 , a=11.979(2), b=13.977(3), c=9.036(1) Å, α=103.15(1), β=94.46(1), γ=115.12(1)°, V=1307.5(4) Å 3, Z=2. Final residuals for 1: R=0.0493, R w=0.0660. Crystal data for MoOCl 2(dppe)(Py) ( 2): P2 1/ c, a=11.480(2), b=17.854(2), c=15.693(2) Å, β=115.51(1)°, V=2982.3(7) Å 3, Z=4. Final residuals for 2: R=0.0458, R w=0.0769. The molecules of 1 were found to be linked by two ClMo bridges (3.018 and 3.082 Å) into infinite chains.