Influence of Nucleation Agents Concentration on Crystallization Structure and Properties of Glass-ceramics

Deep color glass-ceramics is prepared by using gold tailings as the main raw material, and Cr2O3 is added as nucleation agent. Influence of different Cr2O3 additions on crystallization structure and properties of CaO-MgO-Al2O3-SiO2 glass-ceramics has been discussed so as to select optimum additions. DTA is employed to determine optimum crystallization and nucleation temperatures; XRD and SEM are used to characterize microstructure of each sample; and performance indexes, such as water absorption, bulk density, flexural strength and so on, are also determined. Experimental results show that when 3wt% Cr2O3 is introduced, fine glass-ceramics with diopside as the main crystal and Ca-Fe diopside as the second-crystal is obtained, and its corresponding performance indexes are as follows： water absorption 0.12%, bulk density 2.56 g/cm^3, and flexural strength 70.01 Mpa.

Microstructure and forming mechanism of metals subjected to ultrasonic vibration plastic forming: A mini review

Compared with traditional plastic forming,ultrasonic vibration plastic forming has the advantages of reducing the forming force and improving the surface quality of the workpiece.This technology has a very broad application prospect in industrial manufactur-ing.Researchers have conducted extensive research on the ultrasonic vibration plastic forming of metals and laid a deep foundation for the development of this field.In this review,metals were classified according to their crystal structures.The effects of ultrasonic vibration on the microstructure of face-centered cubic,body-centered cubic,and hexagonal close-packed metals during plastic forming and the mech-anism underlying ultrasonic vibration forming were reviewed.The main challenges and future research direction of the ultrasonic vibra-tion plastic forming of metals were also discussed.

Structure and superconducting properties of Ru_(1-x)Mo_(x)(x=0.1-0.9)alloys

We report the detailed crystal structures and physical properties of Ru_(1-x)Mo_(x)alloys in the solid solution range of x=0.1-0.9.Structure characterizations indicate that the crystal structure changes from the hcp-Mg-type,toβ-CrFe-type,and then bcc-W-type.The measurements of physical properties show that the Ru_(1-x)Mo_(x)samples with x≥0.2are superconductors and the superconducting transition temperature T_c as a function of Mo content exhibits a dome-like behavior.

Crystal structure,phase transitions,and thermodynamic properties of magnesium metavanadate(MgV_(2)O_(6))

As a promising anode material for magnesium ion rechargeable batteries,magnesium metavanadate(MgV_(2)O_(6))has attracted considerable research interest in recent years.A MgV_(2)O_(6)sample was synthesized via a facile solid-state reaction by multistep-firing stoichiometric mixtures of MgO and V2O5 powder under an air atmosphere.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)occurred at 841 K and the enthalpy change was 4.37±0.04 kJ/mol.The endothermic effect at 1014 K and the enthalpy change was 26.54±0.26 kJ/mol,which is related to the incongruent melting ofβ-MgV_(2)O_(6).In situ XRD was performed to investigate phase transition of the as-prepared MgV_(2)O_(6)at high temperatures.The cell parameters obtained by Rietveld refinement indicated that it crystallizes in a monoclinic system with the C2/m space group,and the lattice parameters of a=9.280 A°,b=3.501 A°,c=6.731 A°,β=111.76°.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)was further studied by thermal kinetics,indicating that this process is controlled first by a fibril-like mechanism and then by a spherulitic-type mechanism with an increasing heating rate.Additionally,the enthalpy change of MgV_(2)O_(6)at high temperatures was measured utilizing the drop calorimetry,heat capacity was calculated and given as:Cp=208.3+0.03583T-4809000T^(−2)(298-923 K)(J mol^(−1)K^(−1)),the high-temperature heat capacity can be used to calculate Gibbs free energy of MgV_(2)O_(6)at high temperatures.

The Crystal Structure Study of CaSrFe0.75Co0.75Mn0.5O6−δ by Neutron Diffraction

The crystal structure of CaSrFe0.75Co0.75Mn0.5O6−δ is investigated through neutron diffraction techniques in this study. The material is synthesized using a solid-state synthesis method at a temperature of 1200˚C. Neutron diffraction data is subjected to Rietveld refinement, and a comparative analysis with X-ray diffraction (XRD) data is performed to unravel the structural details of the material. The findings reveal that the synthesized material exhibits a cubic crystal structure with a Pm-3m phase. The neutron diffraction results offer valuable insights into the arrangement of atoms within the lattice, contributing to a comprehensive understanding of the material’s structural properties. This research enhances our knowledge of CaSrFe0.75Co0.75Mn0.5O6−δ, with potential implications for its applications in various technological and scientific domains.

Analyses of Reaction Mechanisms among Different Sulfonation Reagents and m-Diphenylamine and Crystal Structures of the Formed Compounds

In the traditional process, m-phenylenediamine reacts with fuming sulfuric acid at high temperature to get intermediates, and then after dehydration occurs intramolecular rearrangement to get 2,4-diaminobenzenesulfonic acid. Traditional methods need to consume a lot of fuming sulfuric acid or concentrated sulfuric acid, resulting in high industrial large-scale production cost, more waste, and posing a serious environmental pollution risk. In this thesis, three different sulfonation reagents were used for the sulfonation reaction of m-phenylenediamine, and the reaction mechanisms and crystal structures of the three pathways were investigated. The three routes are: 1) one-step synthesis of monosulfonated compound 1 from raw material and sulfur trioxide (SO3);2) rapid reaction of raw material and chlorosulfonic acid to synthesize bisulfonated compound 2;3) direct eutectic crystallization of raw material and ordinary sulfuric acid to obtain compound 3. The crystal structure of the compounds synthesized by three paths was analyzed by X-ray single crystal diffraction, and compound 1 was characterized by NMR, Fourier infrared spectra, UV-visible spectrum and Mass spectrometry. The one-step synthesis of SO3 as a sulfonation reagent has the advantages of mild reaction conditions, simple operation and low cost.

Co-crystallization of Resorcin[4]arene Tetracarboxylic Acid with Triethylamine:Synthesis and Crystal Structure

Treatment of resorcin[4]arene tetracarboxylic acid 1 with triethylamine in the presence of Co（CH3COO）2·4H2O and 4,4 -bipyridine gave a co-crystallization 14-·4Et3NH＋（C32H20O164-·4Et3NH＋,Mr=1069.27） from ethanol and water.The compound was structurally determined by single-crystal X-ray diffraction.The crystal belongs to monoclinic,space group P21/n,with a=8.1763（18）,b=12.913（3）,c=28.724（7） ,β=97.574（4）o,V=3006.3（12） 3,Z=2,Dc=1.181 g/cm3,F（000）=1152,Rint=0.0275,T=293（2） K,μ=0.086 mm-1,the final R=0.0634 and wR = 0.1752 for 5082 observed reflections with I 〉 2σ（I）. The co-crystallization is very stable at room temperature. Possibly, a network of N-H…O（=C） plays an important role in the structure. Meanwhile, the compound emits a weak cyan luminescence with peak maximum band at 458 nm.

Extending the Lifetime of Copper-beryllium Alloys as Plastic Injection High-end Needle Valve Mold Nozzle Tips Through a Heat-treatment-based Microstructure Optimization Approach

The relationship between the microstructure and the practical performance of two different copper-beryllium alloys including their lifetime has been investigated.Herein,two valves made of two different alloys with very similar compositions and the same heat treatment methods were investigated by various standard techniques including metallography,X-ray diffraction,chemical composition,microhardness,and thermal conductivity measurements.Although both alloys experienced the same heat-treatment processes,they revealed different thermal and mechanical properties due to the minor difference in their chemical composition.The alloy providing a longer lifetime (40%more) as the tip had a higher thermal conductivity of 280.3 W(m·K)^(-1) (about two times that of the other alloy).Regarding the metallography images and the measured thermal conductivity values of the alloys,the extended lifetime of the nozzle with the optimum performance is ascribed to its biphasic microstructure and the minor grain boundaries and interfacial thermal resistance.And important difference in the chemical composition was investigated in this study.

Investigation on the crystal structure and mechanical properties of the ternary compound Mg_(11-x)Zn_(x)Sr combined with experimental measurements and first-principles calculations

A new ternary compound,Mg_(11-x)Zn_(x)Sr in the Mg-Zn-Sr system was observed and studied using Scanning Electron Microscopy(SEM),Energy-Dispersive Spectroscope(EDS),X-Ray Diffraction(XRD)and Transmission Electron Microscopy(TEM).The XRD patterns were refined by the Rietveld refinement method and the results revealed that the crystallized Mg_(11-x)Zn_(x)Sr phase belonged to tetragonal I41/amd space group and had the Cd_(11)Ba prototype.The Mg atoms were successfully doped into Zn_(11)Sr crystal lattice by occupying Zn atomic sites.Moreover,the Rietveld refinement and computational results demonstrated a gradual decrease in the a-axis and c-axis lattice parameters with decreasing concentration levels of Mg coordination substitution in the lattice of Mg_(11-x)Zn_(x)Sr compound.The elastic constants and modulus of the Mg_(11-x)Zn_(x)Sr compounds calculated by first-principles calculations(FPC)indicated they were increased with the increasing of Zn content.The variation of hardness,D-band widths and the total density of states for Mg_(11-x)Zn_(x)Sr compounds with Zn content was discussed.

Multifunctional Perovskite Photodetectors: From Molecular-Scale Crystal Structure Design to Micro/Nano-scale Morphology Manipulation

Multifunctional photodetectors boost the development of traditional optical communication technology and emerging artificial intelligence fields, such as robotics and autonomous driving. However, the current implementation of multifunctional detectors is based on the physical combination of optical lenses, gratings, and multiple photodetectors, the large size and its complex structure hinder the miniaturization, lightweight, and integration of devices. In contrast, perovskite materials have achieved remarkable progress in the field of multifunctional photodetectors due to their diverse crystal structures, simple morphology manipulation, and excellent optoelectronic properties. In this review, we first overview the crystal structures and morphology manipulation techniques of perovskite materials and then summarize the working mechanism and performance parameters of multifunctional photodetectors. Furthermore, the fabrication strategies of multifunctional perovskite photodetectors and their advancements are highlighted, including polarized light detection, spectral detection, angle-sensing detection, and selfpowered detection. Finally, the existing problems of multifunctional detectors and the perspectives of their future development are presented.

Pressure-induced phase transition and electronic structure evolution in layered semimetal HfTe_(2)

Motivated by the recent experimental work,the pressure-induced structural transition of well-known two-dimensional(2D)1T-Hf Te_(2)was investigated up to 50 GPa through the advanced CALYPSO structure search technique combined with the first-principles calculations.Our calculations suggested that the 1T-Hf Te_(2)will first transform to C2/m phase at 3.6 GPa with a volume reduction of 7.6%and then to P62m phase at 9.6 GPa with a volume collapse of 4.6%.The occurrences of 3D C2/m and P62m phases mainly originated from the enhanced Te-Te interlayer coupling and the drastic distortions of Hf-Te polyhedrons in P3m1 phase under compression.Concomitantly,the coordination number of Hf atoms increased from six in P3m1 to eight in C2/m and eventually to nine in P62m at elevated pressure.The metallic and semimetallic nature of C2/m and P62m phases were characterized,and the evidence of the reinforced covalent interactions of Te-Hf and Te-Te orbitals in these two novel high-pressure phases were manifested by the atom-projected electronic DOS and Bader charge.

Probing the effects of lithium doping on structures, properties, and stabilities of magnesium cluster anions

Bimetallic clusters have aroused tremendous interest because the property changes like structure,size,and composition have occurred.Herein,a structural search of the global minimum for anionic LiMg_(n)^(-)(n=2-11) clusters is performed using an efficient crystal structure analysis by particle swarm optimization(CALYPSO) structural searching program with subsequent density functional theory(DFT) calculations.A great variety of low energetic isomers are converged,and the most stable ones are confirmed by comparing their total energy of each size.It is found that the LiMg_(n)^(-)clusters are structurally consistent with corresponding Mg clusters anions except for LiMg_(5)^(-)and LiMg_(7)^(-).In all the doped clusters,the Li atom prefers to occupy the convex position.Simulated photoelectron spectra(PES),Infrared(IR),and Raman spectra of LiMg_(n)^(-)could be used as an essential evidence for identifying cluster structures experimentally in the future.Stability study reveals that a tower-like structure of LiMg_(9)^(-)has prominent stability and can be identified as a magic number cluster.The reason might be that there are both closed-shell 1S^(2)1P^(6)1D^(10)2S^(2) electronic configurations and stronger Li-Mg bonds caused by sp hybridization in the LiMg_(9)^(-)cluster.

THE STRUCTURE OF AGGREGATION STATE AND ISOTHERMAL CRYSTALLIZATION KINETICS OF NYLON-1010

The structure of aggregation state and isothermal crystallization behavior of Nylon-1010 have been studied by WAXD,DSE,Variance-Range Function and density measurement.The results show that crystallization of Nylon-1010 has the most suitable annealing temperature,the crystals of the Nxlon-1010 are two-dimension heterogeneous nucleation.Both low treatment temperature and high crystallization te,temperature are disadvantageous for Nylon-1010 crystal growth.

Experimental Investigation of Crystal Structure of Zr 0.98 NiGe 2.94 and Phase Equilibria in Zr-Ni-Ge System

Based on the results of electron probe microanalysis(EPMA)and X-ray diffraction(XRD),the isothermal sections of Zr-Ni-Ge ternary system at 973 K and 1173 K were constructed through alloy sampling approach.It is worth noting that the crystallographic information of the formerly reportedτ2(Zr_(0.98)NiGe_(2.94))was determined,which belongs to the space group Pbcm(No.57).Besides the formerly reported ternary compounds,τ1(Zr_(6)Ni_(16)Ge_(7)),τ_(2)(Zr_(0.98)NiGe_(2.94)),τ_(3)(Zr_(3)Ni_(4)Ge_(4)),τ_(4)(ZrNiGe)andτ_(5)(Zr_(2)Ni_(0.54)Ge_(0.46)),a new ternary phase namedτ_(6)with the composition of Zr_(39)Ni_(18)Ge_(43)was primarily detected in this work.In addition,an invariant reaction Ni_(5)Ge_(3)+τ_(4)τ_(1)+τ_(3)between 973 K and 1173 K was deduced.

Structure of Cu-Phthalocyanine Vacuum Deposited on Inclined Glass Substrates

Cu-phthalocyanine is widely studied as a hole-transport layer in organic electronic devices. Since Cu-phthalocyanine is a molecular solid, the crystal structure depends on a circumstance to a great extent. Vacuum deposited layers were known to consist of two consecutive layers. In this article, Cu-phthalocyanine was deposited on the glass substrate inclined at several angles. The thickness of the first layer was found to be dependent on the substrate angle.

Application of machine learning in perovskite materials and devices:A review

Metal-halide hybrid perovskite materials are excellent candidates for solar cells and photoelectric devices.In recent years,machine learning(ML)techniques have developed rapidly in many fields and provided ideas for material discovery and design.ML can be applied to discover new materials quickly and effectively,with significant savings in resources and time compared with traditional experiments and density functional theory(DFT)calculations.In this review,we present the application of ML in per-ovskites and briefly review the recent works in the field of ML-assisted perovskite design.Firstly,the advantages of perovskites in solar cells and the merits of ML applied to perovskites are discussed.Secondly,the workflow of ML in perovskite design and some basic ML algorithms are introduced.Thirdly,the applications of ML in predicting various properties of perovskite materials and devices are reviewed.Finally,we propose some prospects for the future development of this field.The rapid devel-opment of ML technology will largely promote the process of materials science,and ML will become an increasingly popular method for predicting the target properties of materials and devices.

Predictive modeling of critical temperatures in magnesium compounds using transfer learning

This study presents a transfer learning approach for discovering potential Mg-based superconductors utilizing a comprehensive target dataset.Initially,a large source dataset(Bandgap dataset)comprising approximately∼75k compounds is utilized for pretraining,followed by fine-tuning with a smaller Critical Temperature(T_(c))dataset containing∼300 compounds.Comparatively,there is a significant improvement in the performance of the transfer learning model over the traditional deep learning(DL)model in predicting Tc.Subsequently,the transfer learning model is applied to predict the properties of approximately 150k compounds.Predictions are validated computationally using density functional theory(DFT)calculations based on lattice dynamics-related theory.Moreover,to demonstrate the extended predictive capability of the transfer learning model for new materials,a pool of virtual compounds derived from prototype crystal structures from the Materials Project(MP)database is generated.T_(c) predictions are obtained for∼3600 virtual compounds,which underwent screening for electroneutrality and thermodynamic stability.An Extra Trees-based model is trained to utilize E_(hull)values to obtain thermodynamically stable materials,employing a dataset containing Ehull values for approximately 150k materials for training.Materials with Ehull values exceeding 5 meV/atom were filtered out,resulting in a refined list of potential Mg-based superconductors.This study showcases the effectiveness of transfer learning in predicting superconducting properties and highlights its potential for accelerating the discovery of Mg-based materials in the field of superconductivity.

Combined use of fly ash and silica to prevent the long-term strength retrogression of oil well cement set and cured at HPHT conditions

The long-term strength retrogression of silica-enriched oil well cement poses a significant threat to wellbore integrity in deep and ultra-deep wells, which is a major obstacle for deep petroleum and geothermal energy development. Previous attempts to address this problem has been unsatisfactory because they can only reduce the strength decline rate. This study presents a new solution to this problem by incorporating fly ash to the traditional silica-cement systems. The influences of fly ash and silica on the strength retrogression behavior of oil well cement systems directly set and cured under the condition of 200°C and 50 MPa are investigated. Test results indicate that the slurries containing only silica or fly ash experience severe strength retrogression from 2 to 30 d curing, while the slurries containing both fly ash and silica experience strength enhancement from 2 to 90 d. The strength test results are corroborated by further evidences from permeability tests as well as microstructure analysis of set cement. Composition of set cement evaluated by quantitative X-ray diffraction analyses with partial or no known crystal structure(PONKCS) method and thermogravimetry analyses revealed that the conversion of amorphous C-(A)-S-H to crystalline phases is the primary cause of long-term strength retrogression.The addition of fly ash can reduce the initial amount of C-(A)-S-H in the set cement, and its combined use with silica can prevent the crystallization of C-(A)-S-H, which is believed to be the working mechanism of this new admixture in improving long-term strength stability of oil well cement systems.

Synthesis and Structure of A Novel Caged Bicyclic Phosphate Flame Retardant

PI novel caged bicyclic phosphate flame retardant tri(1-oxo-2,6,7-trioxa-1-phosphabicyclo [2.2.2] octane-methyl) phosphate (Trimer) was synthesized from 1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo [2.2.2] octane (PEPA) and phosphorus oxychloride in this paper. Its structure was characterized by elemental analysis. FTIR, H-1 NMR. P-31 NMR and X-ray diffraction analysis.

Synthesis and Structure Analysis of N-(Dehydroabietyl)maleamic Acid

N-（Dehydroabietyl）maleamic acid was synthesized from dehydroabietylamine and maleic anhydride.Its structure was characterized by IR,1 H-and 13 C-NMR spectra.The stereo structure of the title compound was also unambiguously confirmed by X-ray crystal structure analysis.The white crystal crystallizes in the monoclinic system,space group P2 1 with a=12.075（2）,b=10.377（2）,c=17.840（4）,β=100.31（3） °,V=2199.3（8） 3,R=0.0618 and wR=0.1437.Two crystallographically independent molecules with different conformations co-exist in the unit.In each molecule,the two cyclohexane rings form a trans ring junction with chair and half-chair conformations,respectively.The C=C double bond between two carbonyl groups is in a Z configuration.Intermolecular and intramolecular hydrogen bonds coexist to stabilize the structure.