Graphite Carbone Structure

Carbon graphite is a crystalline form of carbon consisting of layers of hexagonal carbon atoms arranged in a two-dimensional “graphene” structure. Graphene layers are stacked on top of each other, forming a three-dimensional structure with a high degree of anisotropy. The carbon atoms within each layer are linked together by strong covalent bonds, creating a strong, stable lattice structure. However, the layers themselves are held together by weak van der Waals forces, enabling them to slide easily over each other. The properties of carbon graphite are highly dependent on the orientation and alignment of the graphene layers. When the layers are aligned parallel to each other, the material exhibits high strength and stiffness along the alignment direction, but is weaker and more flexible in other directions. Carbon graphite is used in a variety of applications where high strength, rigidity and electrical conductivity are required. Some common applications include electrical contacts, electric motor brushes, and as a structural material in aerospace and defense applications. The aim of our work is to describe the structure of graphite, its physical and chemical properties and its applications.

Structural, magnetic properties, and electronic structure of hexagonal FeCoSn compound

The structural, magnetic properties, and electronic structures of hexagonal Fe Co Sn compounds with as-annealed bulk and ribbon states were investigated by x-ray powder diffraction（XRD）, differential scanning calorimetry（DSC）, transmission electron microscope（TEM）, scanning electron microscope（SEM）, magnetic measurements, and first-principles calculations. Results indicate that both states of FeCoSn show an Ni_2In-type hexagonal structure with a small amount of FeCo-rich secondary phase. The Curie temperatures are located at 257 K and 229 K, respectively. The corresponding magnetizations are 2.57 μB/f.u. and 2.94 μB/f.u. at 5 K with a field of 50 kOe（1 Oe = 79.5775 A·m^（-1））. The orbital hybridizations between 3 d elements are analyzed from the distribution of density of states（DOS）, showing that Fe atoms carry the main magnetic moments and determine the electronic structure around Fermi level. A peak of DOS at Fermi level accounts for the presence of the FeCo-rich secondary phase. The Ni_2In-type hexagonal FeCoSn compound can be used during the isostructural alloying for tuning phase transitions.

Effect of substrate temperature on microstructural and optical properties of ZnO films grown by pulsed laser deposition

ZnO thin films were deposited on n-Si （111） at various substrate temperatures by pulsed laser deposition （PLD）. X-ray diffraction （XRD）, photoluminescence （PL）, Fourier transform infrared spectrophotometer （FTIR）, and scanning electron microscopy （SEM） were used to analyze the structure, morphology, and optical property of the ZnO thin films. An optimal crystallized ZnO thin film was obtained at the substrate temperature of 600℃. A blue shift was found in PL spectra due to size confinement effect as the grain sizes decreased. The surfaces of the ZnO thin films were more planar and compact as the substrate temperature increased.

Preparation and characterization of ultrafine zinc oxide powder by hydrothermal method

With Zinc acetate and sodium hydroxide as raw materials,while polyethylene glycol employed as dispersant agent, ultrafine zinc oxide powder was synthesized by hydrothermal method.Influence of NaOH concentration on morphology of ZnO powder was studied.The as-synthesized ZnO powder looked like flower cluster and consisted of microrods with hexagonal morphologies.The crystal structure and optical property of the as-prepared powder were also characterized using XRD,UV-visible absorption spectrum and photoluminescence spectrum.The results indicate that ZnO powder is of hexagonal wurtzite structure and well crystallized with high purity.There is a strong excitation absorption peak at 300 nm in UV-visible absorption spectrum and blue shift exists obviously.The optical property of ZnO powder is excellent.

Preternatural Hexagonal High-Entropy Alloys: A Review

Recently,various topics on high-entropy alloys have been reported and great amounts of excellent properties have been investigated,including high strength,great corrosion resistance,great thermal stability,good fatigue and fracture properties,etc.Among all these research activities,high-entropy alloys tend to form face-centered-cubic(FCC)or body-centeredcubic(BCC)solid solutions due to their high-entropy stabilization effect,while the hexagonal structures are rarely reported.Up to now,the reported hexagonal high-entropy alloys are mainly composed of rare-earth elements and transitional elements.Their phase transformation and magnetic properties have also aroused wide concern.This study summarizes the above results and provides the forecast to the future.

Synthesis and Characterization of Novel Super Microporous Tin-doped Zirconium Oxide

The super microporous tin-doped zirconium oxides were successfully synthesized by sol-gel method using zirconyl chloride as Zr source, tin chloride as Sn source and cetyltrimethylammonium bromide （CTMAB） as template under hydrothermal or refluxing conditions. The structures of the resultant materials were characterized by XRD, BET, FTIR, TG-DTA, XRF and HRTEM techniques. Experimental results indicated that the framework of the samples is typically ordered hexagonal structure. The surface area and pore volume of the materials prepared by refluxing method were larger than by hydrothermal method, but the ordering of pore distributions is lower. The thermal stability of the samples was relatively high （〉773 K） and decreased with the increment of tin content.

Shape-controllable Synthesis of Ultrafine ZnO Powders of Different Morphologies

By employing zinc acetate and sodium hydroxide as raw materials, ultrafine ZnO powders with different morphologies were successfully synthesized through hydrothermal method. The influences of the reaction temperature, the OH-/Zn2＋ mol ratio and the reaction time on the morphologies of the ZnO powders were discussed. The reaction conditions were obtained, under which the ZnO of flower-like particles, micro-rods and flake particles was synthesized, respectively. The crystal structures and morphologies of those ZnO particles were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The ZnO with flower-like structures was composed of lots of micro-rods with hexagon morphology. The XRD patterns indicated that the ZnO powders were hexagonal wurtzite structures with high purity. Finally, the growth mechanism of the ZnO particles was discussed.

FCC-to-HCP Phase Transformation in CoCrNi_x Medium-Entropy Alloys

A hybrid first-principles/Monte Carlo simulation is combined with experiments to study the structure and elastic properties of CoCrNi_x(x=1-0.5)alloys.The experimental X-ray diffraction patterns show that the structures have changed from the single-phase face-centered cubic(FCC)structure at x=1-0.8 to the coexistence of FCC and the hexagonal close-packed structures at x=0.7-0.5,which is further confirmed by calculations on mixing energies.The elastic moduli by calculation are basically in agreement with experiments.Room-temperature tension shows that the six alloys have a certain plasticity,the strength and plasticity of the alloys have a linear decrease with the decrease in Ni contents,and the plasticity of the alloys drops from 84 to 23%.Furthermore,first-principles density function theory calculations were employed to reveal the electronic and magnetic structures of alloys.The electron density of states for all alloys is asymmetrical,which illustrates that the alloys are ferromagnetism.It is found that Cr atoms can suppress the ferromagnetism of alloys,since Cr atoms have both positive and negative magnetic moments in all alloys.

Direct Evidence for the Effect of Intermolecular Hydrogen Bonding on Organogels

In order to get direct evidence for the effect of intermolecular hydrogen bonding on the organogels, one arnide group in N-（3, 4, 5-octyloxybenzoyl）-N＇-（4＇-aminobenzoyl）hydrazine（D8） was replaced by a Schiff base group, forming N-（3,4,5-octyloxybenzoyl）-N＇-（4＇-amidobenzoyl） acylhydrazone（T8SchA）. D8 and T8SchA organogels in cyclohexane show the same hexagonal columnar structure. And the hydrogen bonding was demonstrated to be still interacting in the organogels. However, although the molecular geometry of D8 was well retained in T8SchA, the molecular dipole moment of T8SchA is bigger than that of D8 due to the reduction of the number of hydrogen bonds. Thus, the decreased gelling stability of T8SchA compared to that of D8 can only be attributed to the reduction of the number of intermolecular hydrogen bonds, which provides direct evidence that intermolecular hydrogen bonding plays an important role in stabilising organogels.