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The conventional solid-phase sintering method for the preparation of Ln 2 Ti 2 O 7 ceramics using oxides as reactants generally requires higher temperature, larger pressure, and greater energy consumption. In this paper, we synthesize a Eu 2 Ti 2 O 7 ceramic powder in relatively low-temperature molten salt (KCl–NaCl) using Eu 2 O 3 powder and TiO 2 powder as reactants at 1000 °C. The results of XRD, SEM, and element mapping indicate that the product have high phase purity, good crystal morphology and uniform chemical composition. Moreover, Eu 2 Ti 2 O 7 -based glass-ceramics are obtained by sintering with different contents of borosilicate glass. The SEM images of glass-ceramic show that almost no obvious defects or voids are found on the surface of the samples. The values of water absorption for all glass-ceramic waste forms are less than 0.5 %. With the increase of ceramic embedding rate, the hardness of the glass-ceramics first increases and then decreases, while the density gradually increases. When the embedding rate increased to 30 wt%, the hardness of glass-ceramic reaches a maximum of 19.53 GPa. The glass-ceramic waste form embedded with 30 wt% Eu 2 Ti 2 O 7 exhibits very stable chemical durability with a low leaching rate of 1.42 × 10−8 g m−2 d−1 at 90 °C even after 28 days. [ABSTRACT FROM AUTHOR]

The non-uniformity of a single crystal can sometimes be found in biominerals, where surrounding biomacromolecules are incorporated into the growing crystals. This unique composite structure, combining heterogeneity and long-range ordering, enables the functionalization of single crystals. Polymer gel media are often used to prepare composite single crystals, in which the growing crystals incorporate gel networks and form a bi-continuous interpenetrating structure without any disruption to single crystallinity. Moreover, dyes and many kinds of nanoparticles can be occluded into single crystals under the guidance of gel incorporation. On this basis, the bio-inspired method has been applied in crystal morphology control, crystal dyeing, mechanical reinforcement, and organic bulk heterojunction-based optoelectronics. In this paper, the composite structure, the incorporation mechanisms, and the multiple functions of gel-incorporated single crystals are reviewed. [ABSTRACT FROM AUTHOR]

Context: Ammonium perchlorate (NH4ClO4, abbreviated as AP) has the advantages of high oxygen content, high density, and good compatibility, and has significant application prospects in the field of energetic materials. The crystal morphology has a great influence on the properties and sensibility of energetic materials, and a single experimental means is difficult in exploring the crystals; therefore, the crystal morphology of AP is investigated using molecular dynamics simulation complemented with experiments, to theoretically analyze the differences in AP crystal habit and the interactions between solvent molecules and the main growing crystal surfaces of AP. The results show that AP crystal is mainly composed of five independent crystal surfaces (0 0 1), (0 1 0), (1 0 0), (1 0 1), and (1 0 −1) in vacuum using the BFDH laws, with (0 0 1) surface being the main growth crystal surface. In contrast, in H2O solvent, the (1 0 1) and (1 0 −1) surfaces disappear, and the AP mainly consists of (0 0 1), (0 1 0), and (1 0 0) surfaces with a rectangular shape. The crystal morphology obtained from theoretical prediction is in good agreement with that obtained from experimental culture. This paper can provide a new idea for the cultivation and preparation of AP large crystals, and promote the application of AP crystals in energetic materials. Methods: The crystal morphologies of AP in vacuum and H2O solvent under Dreiding force field were predicted based on attachment energy model by using molecular dynamics method in Materials Studio 2019 software. The entire molecular dynamics simulation was carried out under the NTV system, the temperature control method was selected as Anderson, and the system temperature was set to 298 K. The simulation time was set to 40 ps, the step size was set to 1 fs, and the data were outputted every 5000 steps. [ABSTRACT FROM AUTHOR]

Oiling‐out is a common phenomenon in industrial crystallization processes that not only prolongs the total operating time but also leads to undesirable crystal morphology, making it challenging to control crystallization paths. This review provides a comprehensive overview of the oiling‐out phenomenon in organic small molecule crystallization. First, the formation mechanisms of oiling‐out are summarized from both thermodynamic and dynamic perspectives, providing the theoretical foundation for understanding the phenomenon. Then, the universal characterization methods for studying the oiling‐out phenomenon of organic small molecules are introduced in detail, covering both offline and online analytical tools. Moreover, the regulation strategy for oiling‐out, including solvents, impurities, seeding, temperature, and mixing methods are discussed. This paper also focuses on the application of oiling‐out in co‐assembly and crystal shape modulation. Finally, future opportunities and challenges are presented to address the current shortcomings and application bottlenecks in the study of organic small molecule oiling‐out phenomena. This review aims to provide valuable insights and guidance for researchers working on the crystallization of organic small molecules, particularly in the pharmaceutical industry, to better understand, control, and utilize the oiling‐out phenomenon. [ABSTRACT FROM AUTHOR]

In this paper, the melting memory effect generated by a novel cyclic thermal treatment protocol with form II as "seeds" on the polymorphic transformation in isotactic polybutylene-1(iPB-1) was investigated. Polar Optical Microscope (POM), wide angle X-ray diffraction (WAXD) and Fourier transform infrared spectroscopy (FTIR) were used to study the changes of morphology and crystal form II → I transition during aging. Selected crystallization temperature (Tsc) and melting temperature (Tsm) were applied to generate residual nuclei of form II. Both cycled and uncycled samples were analyzed to demonstrate the formation of crystal I and polymorphic transformation. The results indicate that the melting memory has a significant effect on tetragonal modification, leading to an increased nucleation density and an accelerated nucleation speed. The ordered chain sequences in crystal II initiated the formation of crystal nuclei of form I, resulting in a rapid conversion and increased transition degree during the hexagonal crystal growth. Form I was found to have two formation pathways, including the transformation of the unstable crystal form II and the direct formation from residual crystal and melt, which have been rarely discussed before and may shed light on understanding of crystal formation mechanism in polymorphism polybutene-1. [ABSTRACT FROM AUTHOR]

Engineering of organic single crystal toward controllable and aligned patterns at microscale is crucial to the realization of highly integrated organic photonic devices and optoelectronics. However, precise positioning and controllable morphology of crystal structures is still challenging due to the strict conditions for crystal growth. In this paper, a solution based crystal regulation strategy with the assistance of template‐constrained growth method and femtosecond laser processing technology is developed to prepare aligned crystalline microribbon arrays. Simple solvent evaporation results in the random distribution and orientation of self‐assembled crystalline microribbons while it tends to form highly crystalline and orderly microribbon arrays assisted by the confined template microchannels. The large‐scale microribbon array can be fabricated as organic photodetectors with sensitive and fast response under 405 nm illumination. By virtue of the femtosecond laser processing technique, the microribbon arrays are precisely processed into a series of crystal subunits and each microribbon subunit can function as an individual microcavity resonator to produce stable, high‐quality organic laser. The facile solution based template‐constrained self‐assembly and femtosecond laser processing method provide novel strategies to generate highly oriented and controllable crystal structures for the potential applications in integrated organic lasers and optoelectronics. [ABSTRACT FROM AUTHOR]

This paper proposes a technique for producing underground backfilling materials using enzyme-induced calcium carbonate precipitation (EICP) technology to address the growing ecological security concerns caused by coal mining. To augment the mineralization impact of EICP, diverse levels of organic substances, including yeast extract, peptone, and skimmed milk powder, were incorporated into the cementing solution to offer a greater number of nucleation sites for the precipitation of calcium carbonate. The results indicate that (1) based on visual observations, all the sand columns remained intact after cementation, demonstrating a good cementation effect; (2) unconfined compressive strength (UCS) test findings demonstrated that the introduction of organic components effectively augmented the strength of EICP. Among these materials, skimmed milk powder exhibited the most significant effect, resulting in a 66.01% increase in the UCS of EICP at a concentration of 6 g/L. Peptone also showed a positive impact, albeit to a lesser extent, while yeast powder had a relatively lower effect; (3) The utilization of scanning electron microscopy (SEM) revealed a significant diversification in the crystal morphology of calcium carbonate when combined with organic materials through the EICP process. An X-ray diffraction (XRD) test confirmed the presence of calcite and vaterite. This finding implies that the molecular structure of calcium carbonate is enhanced by the inclusion of organic materials. [ABSTRACT FROM AUTHOR]

Enzyme-induced carbonate precipitation (EICP) is an emerging and environment-friendly geotechnical technique for soil improvement. Despite the extensive amount of previous studies focusing on the mechanical properties of biocemented samples with varying calcium carbonate content, less is known about the cementitious property of calcium carbonate crystals generated in the EICP process. This paper presents a systematic study on the effect of cementation solution concentration (CCS) on cementitious property of calcium carbonate crystals. Solution tests were conducted to ascertain the dominant factor causing the retarding effect of CCS. Glass slide tests and ultrasonic oscillation tests were performed to evaluate the cementitious property of calcium carbonate crystal. The results of solution tests indicated that the higher CCS would affect calcium carbonate production and calcium conversion efficiency, which is mainly caused by the concentration of CaCl2 rather than urea. The increase in CCS will cause calcium conversion efficiency to decrease significantly, and calcium carbonate production will also decrease once CCS exceeds a threshold value. The higher CCS contributes to formation of larger calcium carbonate crystals and has little effect on the morphological characteristics of the crystal. Glass slide tests showed that mineral composition is controlled by the CCS of EICP solution. Increasing the CCS results in the increased vaterite content, which affects the cementitious property of calcium carbonate crystal, especially for CCS is higher than 1.0 M. The results are expected to help identify the retarding effect of CCS and to provide a reference for optimizing the cementitious property of calcium carbonate crystals. [ABSTRACT FROM AUTHOR]

This paper provides a detailed technological characterization of the Roman opus sectile glasses (second century AD) coming from the renowned Gorga collection. Nine glass samples corresponding to imitations of the porfido verde antico, cipollino rosso, rosso antico, giallo antico, diaspro nero e giallo, semesanto and agate/alabaster stones were studied. The aim of this study was twofold: (i) archaeometric, i.e., to provide valuable data on the production, raw materials and techniques of these refined Roman glasses that mimic precious stones and (ii) methodological, i.e., to highlight the good performance of combining polished thin sections and local probe measurements for the study of glassy microstructures. Based on the nature of the flux used, the glasses from the samples were classified as either natron-type or mixed-type (natron/plant ash). The latter stem from remelted glasses and contain relict grains of wollastonite that were not found in the pure natron samples. Relict wollastonite crystals appear to be a proficient petrographic marker to spot recycled glasses along with the commonly used chemical fingerprints. Different production and colouring techniques were identified, even for a given type of imitated stone. Metallic Cu, Ca antimonates and Pb-Fe antimonates were the three opacifiers used for the opaque glasses. Based on the crystal morphologies, metallic Cu and Ca antimoniates were possibly synthesized in situ simultaneously with the glass, whilst the Pb-Fe antimonates were prepared ex situ. The working temperatures for these glasses were estimated within the 900–1100 °C range based on the presence and known thermal stability of some identified crystal phases. [ABSTRACT FROM AUTHOR]

We consider the interfacial growth morphologies of crystals growing in contact in crystal mushes, with a specific application to those formed by the solidification of basaltic magma. We focus on the particular case of an augite (pyroxene) crystal growing between two plagioclase crystals. The augite is treated as an equant unfaceted crystal, whereas the plagioclase is faceted, and our treatment applies generally to such combinations. The resulting three-grain junctions in natural rock samples are commonly of two distinct types. In one, the two augite–plagioclase interfaces grow towards each other with opposite curvatures, whereas in the second the curvatures of the interfaces have the same sign, giving a distinctive morphology which we have called an eagle's beak. This paper provides a theoretical framework to provide explanations for both of these morphologies, based on the kinetics of interfacial growth. [ABSTRACT FROM AUTHOR]

An increasing number of researchers are interested in studying CsPbBr3 perovskite solar cells (PSCs) due to their high stability. However, the use of methanol during the spin-coating process is extremely hazardous, both to humans and the environment. CsBr is very soluble in water, but owing to its high specific heat capacity, water causes uneven crystallization and the creation of pores, which negatively impact the performance of CsPbBr3 devices. In this paper, water is introduced as the solvent for CsBr in place of methanol to prepare CsPbBr3 films and ethanol is used as the surface treatment solvent. The morphology and crystal quality of CsPbBr3 films are improved by varying the concentration and spin-coating cycles of the CsBr/H2O solution and adding ethanol post-treatment. The results show that high-quality CsPbBr3 films with reduced grain boundaries and high phase-purity were obtained by spin-coating 100 mg/mL CsBr/H2O solution three times and using ethanol as a post-treatment. The CsPbBr3 solar cells yielded a maximum efficiency of 7.65% and demonstrate long-term stability over 1100 h. [ABSTRACT FROM AUTHOR]

Margarine is a water-in-oil food emulsion and is mostly formulated with selected vegetable oils. This favorable tablespread widely consumes as a butter alternative with both nutritional and economical aspects. The quality of margarine is determined by its textural and rheological properties, which dramatically affect consumer acceptance. Speardability and hardness are considered as the most important textural attributes specifying margarine desirability. The textural and rheological properties of margarine noticeably depend on emulsion characteristics, crystal morphology, processing method, storage condition, fatty acid content and origin. The fat phase of margarine with β′ form crystals develops a smooth and pleasant texture. Rheological measurements could evaluate the emulsion stability, shelf life, meltability and viscoelastic behavior of margarine in different conditions. The physical structure of margarine directly influences spreadability, mouthfeel and meltability and even indirectly impresses on flavor and appearance. This paper focuses on different margarine productions, assesses their viscoelastic and textural characteristics to find out suitable formulation and eventually modifies its physical attributes. [ABSTRACT FROM AUTHOR]

In this paper, the influence of magnetron-sputtered AlN nucleation layers with different thicknesses on ultraviolet (UV) light-emitting diode (LED) chips is studied. First, magnetron-sputtered AlN layers with thicknesses of 8, 25, and 42 nm were prepared on a patterned sapphire substrate (PSS). Subsequently, a 2.8 μm-thick GaN layer was epitaxially grown. We found that when the magnetron-sputtered AlN was 25 nm thick, GaN had the best crystal quality and morphology. Therefore, we grew an 800 nm GaN layer on PSS to analyze the initial growth mechanism of the material. The scanning electron microscopy (SEM) images showed that when the thickness of the sputtered AlN layer was 25 nm, the GaN grains on the sidewall of the PSS cone were the least abundant. In addition, according to the selected area electron diffraction (SAED) test, the (011) crystal plane of GaN appeared on the sidewall of the PSS cone. The (011) crystal plane is the semipolar plane of GaN, which is not conducive to the growth of polar GaN materials. Finally, on this basis, we fabricated UV-LED chips. Among them, the UV-LED chips with the 25 nm magnetron-sputtered AlN layer exhibited the best electrical and optical performance. Overall, this work provides a pathway to improve the performance of UV-LED chips. [ABSTRACT FROM AUTHOR]

To overcome the drawbacks of strong polarity and easy agglomeration of ordinary magnesium hydroxide (MH), hydrothermal modification is customary applied to achieve its excellent dispersion as well as controllable morphology and particle size. In this paper, the influence mechanism of hydrothermal modification is elaborated from microstructure of MH. Structures and surface energy of crystal planes, affinity of water molecules for crystal planes, and crystal growth process are calculated by Materials Studio software. Furthermore, molecular dynamics simulations about solid–liquid interface model of MH and 1 mol L−1 NaOH solution at different temperatures are performed based on the theory of modified attachment energy model. The results indicate that (0 0 1) plane with the smallest surface energy has the strongest thermodynamic stability, equipping modified crystals with lamellar morphology and excellent dispersion. (0 0 1) plane cannot be dissolved easily because of the smallest affinity of water molecules. The magnesium atoms and hydroxyl groups on (1 0 1) plane dissolved are absorbed on (0 0 1) plane, resulting in the large value of I001/I101 in the X‐ray diffraction pattern. The relative growth rate of (1 0 1) plane R101 decreases with the increasing temperature, explaining why crystals become thicker with raising temperature. [ABSTRACT FROM AUTHOR]

In this paper, rare earth ion Nd doped LiLuF4 (LLF) microcrystals were prepared by hydrothermal method. The phase analysis, morphology analysis of the crystals were performed and near infrared optical properties were studied. LLF crystals belong to the scheelite structure of tetragonal system and the space group is I41/a. The LLF microcrystalline materials prepared by hydrothermal method have good crystallinity and the particle size is about 20 μm. The oxygen content of the optimized Nd∶LLF sample is 0. 001 4% (mass fraction). Under excitation of 792 nm wavelength, the main fluorescence emission peak of 3% (mole fraction) Nd-doped LiLuF4 microcrystal is located at 1 047 nm, which belongs to near infrared bands, and its fluorescence lifetime is about 0. 275 1 ms. Furthermore, Nd∶LLF crystal was grown by the Czochralski method and its laser performance was evaluated. The emission cross section of Nd∶LLF crystal at 1 053 nm is 8. 13 ×10 -20 cm2. The laser performance test and analysis show that under the excitation power of 1. 2 W, Nd∶LLF crystal obtains a near-infrared laser output of 0. 123 W at 1 053 nm. [ABSTRACT FROM AUTHOR]

1,1′-Dihydroxy-5,5′-bi-tetrazolium dihydroxylamine salt (TKX-50) is a new type of high-energy low-sense explosive with great application value, but TKX-50 made directly from the reaction has problems such as irregular crystal morphology and relatively large length-diameter, and these factors seriously affect the sensitivity of TKX-50 and limit its large-scale application. The internal defects of TKX-50 crystals have a great influence on their weakness, and studying its related properties is of great theoretical significance and application value. To further investigate the microscopic properties of TKX-50 crystals and to explore the connection between microscopic parameters and macroscopic susceptibility, this paper reports the use of molecular dynamics simulations to construct TKX-50 crystal scaling models with three types of defects—vacancy, dislocation and doping—and conducts molecular dynamics simulations. The influence of TKX-50 crystal defects on the initiation bond length, density, bonding diatomic interaction energy, and cohesive energy density of the crystal was obtained. The simulation results show that the models with a higher bond length of the initiator bond and higher percentage activated the initiator's N-N bond and lowered the bond-linked diatomic energy, cohesive energy density, and density corresponding to higher crystal sensitivities. This led to a preliminary connection between TKX-50 microscopic model parameters and macroscopic susceptibility. The results of the study can provide a reference for the design of subsequent experiments, and the research method can be extended to the research work on other energy-containing materials. [ABSTRACT FROM AUTHOR]

Due to its excellent mechanical properties and high aspect ratio, graphene can significantly improve the water and chloride ion permeability resistance of cementitious materials. However, few studies have investigated the effect of graphene size on the water and chloride ion permeability resistance of cementitious materials. The main issues are as follows: How do different sizes of graphene affect the water and chloride ion permeability resistance of cement-based materials, and by what means do they affect these properties? To address these issues, in this paper, two different sizes of graphene were used to prepare graphene dispersion, which was then mixed with cement to make graphene-reinforced cement-based materials. The permeability and microstructure of samples were investigated. Results show that the addition of graphene effectively improved both the water and chloride ion permeability resistance of cement-based materials significantly. The SEM (scanning electron microscope) images and XRD (X-ray diffraction) analysis show that the introduction of either type of graphene could effectively regulate the crystal size and morphology of hydration products and reduce the crystal size and the number of needle-like and rod-like hydration products. The main types of hydrated products are calcium hydroxide, ettringite, etc. The template effect of large-size graphene was more obvious, and a large number of regular flower-like cluster hydration products were formed, which made the structure of cement paste more compact and thus significantly improved the resistance to the penetration of water and chloride ions into the matrix of the concrete. [ABSTRACT FROM AUTHOR]

MAX phases are layered ternary carbides and nitrides with unique properties, doping transition metals in it is attracting significant attentions for the processing of this relatively new class of materials. In this paper, a magnetic solid solution MAX phase V 2 (Sn 1− x A x)C (A = Mn, Fe, Co) was synthesized by doping Mn/Fe/Co atoms into V 2 SnC by pressure-less sintering. The XRD results show that when x = 0.4, the characteristic peak shifts to the right, and the substitution reaches saturation. SEM and TEM show that doping does not change the original layered morphology and hexagonal crystal form, but only the lattice constants decrease slightly. Magnetic test results indicate that V 2 (Sn 1− x A x)C is a typical low-temperature magnetic material with a Curie temperature around 60 K, and the magnetization increases with the increase of doping amount. Moreover, we explained the reasons of V 2 SnC doping A-site instead of M-site and the changing trend of the magnetic moments by first-principles calculations, which are consistent with the experimental results. [ABSTRACT FROM AUTHOR]

Calcium carbonate has different crystal characteristics, which makes it play different roles in various application fields. The control of calcium carbonate crystal structure, morphology and size is a hot research topic in the preparation of inorganic materials. The preparation of nano calcium carbonate produced from calcium carbide slag can realize the transformation of waste into resource, which is one of the important research fields concerning the recycling of calcium- containing solid wastes. The controllable preparation of calcium carbonate with different crystalline structure and morphology from calcium carbide slag can make the worthless calcium carbide slag transform into high value-added nano grade products with good environmental and economic effects. The preparation methods of nano calcium carbonate from calcium carbide slag are summarized in this paper, the research progress of the control of crystal structure and morphology during the preparation process is discussed emphatically. The results indicate that, during the nucleation and growth of calcium carbonate crystals, controlling the process conditions can further achieve the regulation of crystal structure and morphology by influencing the degree of supersaturation, and the action mechanism varies from different kinds of additives. As the basis for controlling the equilibrium of the crystallization processes, thermodynamics and kinetics can be used to explain the mechanism of action of each influencing factor. [ABSTRACT FROM AUTHOR]

The functionality and performance of the electronic product are heavily dependent on its quality of power device and radio frequency device, thus further determined by the quality of SiC substrate. Hence, the manufacturing of superior SiC single crystal is of significant importance. One popular way of growing large-diameter SiC single crystal is to leverage physical vapor transport (PVT) method. However, this method admits a common challenge in thermal design and flow control. To tackle this problem, a numerical simulation study of the complete process of growing 150 mm SiC single crystal by resistive heating PVT method was proposed in this paper. A mathematical model to capture the growing process, which comprises the pyrolysis and recrystallization of source materials, the porous structure evolution, the heat-mass transport in the system, and the morphology changes of crystal growth front was established. In order to validate our developed model, the numerical simulations were implemented to study the interaction among the crystal growth, the consumption of source materials, and the thermal field changes. The results show that the high temperature on the side of the source area leads to uneven gas flow, and the high temperature at the bottom results in a uniform airflow and a slightly convex crystal surface. Meanwhile, the growth interface adjusts the equilibrium pressure of the gas species through the radial temperature distribution, therefore, the crystal surface grows into an isotherm shape. In addition, the crystal growth rate is positively correlated with the temperature of the source area and the amount of remaining raw materials. The simulation results are consistent with the reported experimental results inherently, which lay a solid foundation for the optimal growth of large-scale and high-quality SiC single crystals. [ABSTRACT FROM AUTHOR]

The boron (B)-sulfur (S) co-doped single crystal diamond was prepared by diffusion device using high purity boron powder and sulfur powder at 1 300 ° under a high temperature vacuum. In this paper, scanning electron microscopy, X-ray energy spectroscopy, Raman spectroscopy, and other tests show that the morphology and crystal quality of diamond change with doping of the two elements. The co-doping diamond crystal surface morphology is complex, and the internal morphology of etch pits and gully is stepped. With the doping amount increases, the steps appear to fracture, and high content of boron and sulfur atoms is detected at the etch pits. The diamond with B-S mass fraction of 0.5 have the highest content of boron and sulfur atoms at the etch pits. With the impurity atoms infiltration, full width at half maximum of Raman increases, and crystal quality of the diamond decreases. Hall testing at room temperature reveals that the diamond resistivity decreases after doping. The samples with the B-S mass fraction of 1 and 2 exhibit p-type conductivity. While the sample with the B-S mass fraction of 0.5, the Hall coefficient is negative and shows n-type conductivity. [ABSTRACT FROM AUTHOR]

Coal-based graphene sheets (GS) and coal-based graphene quantum dots (GQDs) are usually prepared separately. In this paper, symbiosis of coal-based GS and coal-based GQDs was successfully prepared with our proposed preparation method by using three raw coals with different reflectance (collected from Qinshui coalfield, Shanxi Province) as carbon sources. The results showed that coal-based GS and coal-based GQDs can exist stably in the symbiosis and are distributed in different layers, and the GQDs are freely distributed between layers of GS. The average number of GS (N ave) in the three symbiosis is about 7 and the average interlayer spacing (d 002) is about 0.3887 nm. The average diameter of GQDs in the three symbiosis is about 4.255 nm and the average d 002 is about 0.230 nm. The average N ave of the three symbiosis was about 3 and the average d 002 is about 0.361 nm. The morphology and crystal parameters of symbiosis is more similar to that of graphene, the elements are only carbon and oxygen. In the prepared symbiosis, the higher the reflectance of raw coal, the smoother the lattice skeleton and the less vortex-layer structure of GS, and the larger the diameter and the denser the six membered ring of GQDs. The C and O functional groups of the prepared symbionts are similar. The higher the reflectance of coal, the higher the content of Câ€"C/C=C. Under ultraviolet light, the prepared products all emit blue, and the higher the reflectance of coal, the higher the ultraviolet absorption, and the stronger the fluorescence intensity. [ABSTRACT FROM AUTHOR]

Recently, microbially induced carbonate precipitation (MICP) has shown potent potential in the field of civil engineering. The calcium carbonate crystals produced by bacteria during the MICP process play a central role in sticking the soil. However, the morphological changes of calcium carbonate crystals in this process and the mechanical performance of soil in the corresponding stages have not been clearly explored. In this paper, the alterations in the morphology of calcium carbonate crystals were continuously observed via scanning electron microscopy during the MICP process in one week, and the mechanical changes of the samples were monitored every day, so as to reveal the relationship between the morphology of calcium carbonate crystals and the mechanical performance of the samples. The results show that the calcium carbonate crystals undergo a gradual change from ellipsoid to rhombic at the 72nd hour. The mechanical properties of both were greatly improved, among which the compressive strength was increased by 2.78 times compared with the previous time point, and the flexure strength was increased by 2.57 times; this time point was also the time when calcite appears. In addition, we found direct evidence on the first day that bacteria act as the nucleation site of calcium carbonate formation. The above findings have certain guiding significance for the in-depth understanding of the internal microscopic changes of MICP and the influence of calcium carbonate morphology on sample mechanics. [ABSTRACT FROM AUTHOR]

Human health has been seriously endangered by arsenic pollution in drinking water. In this paper, iron hydroxide nanopetalines were synthesized through a precipitation method using KBH4 and their performance and mechanism of As(V) and As(III) removal were investigated. The prepared material was characterized by SEM–EDX, XRD, BET, zeta potential and FTIR analyses. Batch experiments indicated that the iron hydroxide nanopetalines exhibited more excellent performance for As(V) and As(III) removal than ferrihydrite. The adsorption processes were very fast in the first stage, followed a relatively slower adsorption rate and reached equilibria after 24 h, and the reaction could be fitted best by the pseudo-second order model, followed by the Elovich model. The adsorption isotherm data followed to the Freundlich model, and the maximal adsorption capacities of As(V) and As(III) calculated by the Langmuir model were 217.76 and 91.74 mg/g at pH 4.0, respectively, whereas these values were 187.84 and 147.06 mg/g at pH 8.0, respectively. Thermodynamic studies indicated that the adsorption process was endothermic and spontaneous. The removal efficiencies of As(V) and As(III) were significantly affected by the solution pH and presence of PO43– and citrate. The reusability experiments showed that more than 67% of the removal efficiency of As(V) could be easily recovered after four cycles. The SEM and XRD analyses indicated that the surface morphology and crystal structure before and after arsenic removal were stable. Based on the analyses of FTIR, XRD and XPS, the predominant adsorption mechanism was the formation of inner-sphere surface complexes by the surface hydroxyl exchange reactions of Fe–OH groups with arsenic species. This research provides a new strategy for the development of arsenic immobilization materials and the results confirm that iron hydroxide nanopetalines could be considered as a promising material for removing arsenic from As-contaminated water for their highly efficient performance and stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • (Ni x Co 3− x)S 4 NPs were synthetized through cation exchange started from spinel Co 3 S 4 NP. • Composition-catalytic activity relation of (Ni x Co 3− x)S 4 NPs were established. • Structural modulation induced by ionic diffusion provided additional active sites. • Disordered structure facilitated continuous phase transformation into Co/NiOOH. • (Ni 1.2 Co 1.8)S 4 NPs with tailored chemical and structural properties enhanced OER activity. Transition metal spinels are promising oxygen evolution reaction (OER) catalysts; however, their rational design has been impeded by their inherent elemental and structural complexities. To alleviate these issues, this paper describes the role of cation exchange in developing active OER catalysts whose chemical and structural features are tailored while their morphology and crystal structure are maintained for enabling a systematic comparison. Through cation exchange, pre-synthesized Co 3 S 4 spinel nanoparticles (NPs) transform into (Ni x Co 3− x)S 4 NPs with compositions ranging from Co-rich to Ni-rich phases. Apart from stoichiometry, the atomic disorder and chemical state of the metal cations are amended through excessive interdiffusion and interstitial site preference of the cations, evidently helping boost the catalytic activity. Specifically, (Ni 1.2 Co 1.8)S 4 —which exhibits an optimal Ni/Co ratio, high structural disorder, and distinct surface chemical states—shows excellent OER performance (overpotential at 10 mA/cm2: 298 mV). In-depth analyses including in situ Raman spectroscopy and DFT calculations indicate that (Ni 1.2 Co 1.8)S 4 gradually transforms into OER-active Co/NiOOH—which has a unique electronic structure with strong reaction-intermediate-adsorbing characteristics—during the OER cycles. Overall, the study findings underscore the potency of cation exchange as a tool for controlling structural and chemical features, thereby helping explore complex catalyst materials while enhancing their activity. [ABSTRACT FROM AUTHOR]

Protein retarders can not only prolong the setting time of gypsum in application, but also lower the reduction in strength. The chemical activity of proteins is determined by the basic unit of amino acids (AAs). To enhance the understanding of protein retarding action mechanism, this paper focuses on the AAs-adsorbed gypsum structure, and investigated the retarding effects, crystal morphologies, and nanoscale interactions. Results indicate that the AAs had varying retarding effects on gypsum, and the effects from greatest to smallest were L-arginine, L-glutamic, and L-leucine acid. The rate of initial hydration heat release was reduced, and the peak of hydration release was delayed. Retardation of AAs on gypsum involves chemical adsorption on the surface of dihydrate gypsum crystals, which mainly occurs on the (1 2 0) face and affect gypsum morphology. The mechanism of AAs adsorption involves electrostatic interactions between charged functional groups of AAs and gypsum particles, as well as hydrogen bonding at additional carboxyl and amino groups. The adsorption strength depends on longer chained structure and number of functional groups of the AAs. And intrinsic strength of AAs-adsorbed gypsum nanocrystals contributes to the strength reduction on the macroscale. This paper provides basic data for designing and tailoring enhanced protein retarders for gypsum. • The amino acids adsorbed gypsum mechanism was revealed to evaluate protein retarding effects. • Retardation of AAs on dihydrate gypsum crystals mainly occurs on the (1 2 0) face. • Intrinsic strength of AAs-adsorbed gypsum nanocrystals contributes to the strength reduction on the macroscale. • Electrostatic interactions and hydrogen bonding determine the AAs adsorption effects. [ABSTRACT FROM AUTHOR]

In this work, the effect of catalyst viscosity on diamond growth was studied by simulating and analyzing the catalyst convection field in a diamond synthesis chamber in different viscous catalyst systems. The results showed that the low-viscosity catalyst had a high convection velocity, fast carbon flow, and large crystal growth volume, but it easily produced defects during long growth times. The convection velocity in the high-viscosity catalyst was slow, the precipitation rate of carbon was moderate, and the crystal quality was good. It is suitable for growing high-quality large-sized diamond single crystals. The structural properties of the synthesized samples were characterized by optical microscopy and Raman spectroscopy. The synthesis experiment and simulation results were consistent. In this experiment, a new viscosity concept is proposed to control the quality of diamond crystals, in which the crystal morphology is controlled by adjusting the flow field in the catalyst. This is not limited to controlling the synthesis of crystals with different morphologies by changing the temperature gradient in the diamond synthesis chamber. Therefore, this paper establishes the characteristics of a convection field suitable for the growth of diamond crystals using different viscous catalysts and provides an important theoretical reference for cavity optimization and the design of flow fields for new catalysts. [ABSTRACT FROM AUTHOR]

Nanocrystals of VO2(B) have attracted significant attention for their promising performance in electrochemical energy storage applications. Phase-purity and nanocrystal morphology are both crucial factors for the performance of these materials, but given the large number of crystal polymorphs available to VO2, achieving simultaneous control over crystal phase and nanocrystal size is a significant synthetic challenge. This paper describes the impact of water concentration on the synthesis of VO2(B) nanocrystals via solvothermal reaction of a molecular V(IV) precursor in toluene. Using controlled, stoichiometric amounts of water (20 equivalents per vanadium centre) enables access to short nanorods of VO2(B) whose lengths follow a Gaussian distribution with an average and standard deviation of 110 ± 30 nm. Decreasing the amount of water present to two or four equivalents results in formation of VO2(A) nanocrystals and eliminating it entirely results in no reaction. Increasing the amount of water to more than 20 equivalents increases the average length of the VO2(B) nanorods and causes the distribution in rod lengths to evolve from Gaussian to lognormal. This evolution in the size distribution is consistent with changes in a model Gaussian distribution observed upon simulated end-to-end oriented attachment events. These results demonstrate that control over the concentration of water is a useful strategy for tuning the morphology and crystal phase of VO2 nanocrystals. [ABSTRACT FROM AUTHOR]

Bi 4 O 5 Br 2 /Mn x Zn 1-x Fe 2 O 4 nanocomposites with impressive photocatalytic and recyclability properties were synthesised using a microemulsion method. In addition to the photocatalytic effect, the crystal structure and morphology, photoelectrochemical characteristics, magnetic effect and photocatalytic mechanism of Bi 4 O 5 Br 2 /Mn x Zn 1-x Fe 2 O 4 were also investigated. As the best sample, the removal rate of the Bi 4 O 5 Br 2 /Mn x Zn 1-x Fe 2 O 4 photocatalyst with 7.5 wt% Mn x Zn 1-x Fe 2 O 4 to rhodamine B (RhB) reached up to 99.4% within 60 min. The enhanced photocatalyst activity was mainly attributed to the type-II heterojunction formed between Bi 4 O 5 Br 2 and Mn x Zn 1-x Fe 2 O 4 , which not only optimised the energy band structure, but also led to the building of an interior electromagnetic field within the Bi 4 O 5 Br 2 /Mn x Zn 1-x Fe 2 O 4 heterojunction. Meanwhile, the constantly producing and migrating h+ and ·O 2 − were the main active components. In particular, the results of the saturation magnetization tests and magnetic recovery experiments revealed that the magnetic composite photocatalyst can be recovered effectively. The results of the removal rate of RhB remaining at 85.2% after five uses reflected the advantages of the stability of the Bi 4 O 5 Br 2 /Mn x Zn 1-x Fe 2 O 4 photocatalyst. In brief, this paper presented an original idea to develop a novel composite magnetic photocatalyst and research the enhancement mechanism of photocatalysis. [ABSTRACT FROM AUTHOR]

Filamentous crystals such as whisker crystals are often seen not only in metallic liquids, but also in organic liquids and solutions. They are interesting as reinforce materials. However, it remains challenging to induce filamentous crystals due to an incomplete understanding of the mechanisms behind their formation. In this paper, we investigate filamentous crystal growth in viscous organic liquids. It is found that filamentous crystals grow via an extraordinary dynamical path, where the molecules locally evaporate to bubbles and then redeposite to the tip of growing crystalline filaments. We also succeeded in controlling whether filamentous or faceted crystal growth is selected by inducing or suppressing the bubbles. [ABSTRACT FROM AUTHOR]

Monocrystalline silicon slicing is the first step in making chips, and the surface quality of silicon wafers directly affects the quality of later processing and accounts for a large proportion in the chip manufacturing cost. Ultrasonic vibration assisted wire saw (UAWS) is an effective sawing process for cutting hard and brittle materials such as monocrystalline Si, which can significantly improve the surface quality of silicon wafers. In order to further study the formation mechanism of the surface morphology of single crystal silicon sliced by UAWS, a new model for prediction of wafer surface morphology in UAWS slicing single crystal silicon based on mixed material removal mode is presented and verified by experiments in this paper. Firstly, the surface model of diamond wire saw tool is established by equal probability method. Then, the trajectory equation of arbitrary abrasive particles on the surface of wire saw is derived and analyzed. Thirdly, a new model for prediction of the wafer surface morphology based on mixed material removal mode is presented. Finally, the prediction model is verified by UAWS slicing experiment, and the effects of slicing parameters such as wire saw speed, feed speed, and workpiece rotate speed on the surface quality of silicon wafer were studied. It shows that the predicted wafer surface morphology and the experimental wafer surface morphology are similar in some characteristics, and the average error between the experimental and the theoretical values of the wafer surface roughness is 11.9%, which verifies the validity of the prediction model. [ABSTRACT FROM AUTHOR]

Microfluidics is a new experimental approach that investigates the processes related to fluids flowing through small channels or porous media. Microfluidic chips, the core elements of the microfluidic technique, consist of quasi-2-dimensional pore structures etched and sealed in transparent materials. Fluids are allowed to flow through the chips, and real-time observations can be made about the transport and reactions of fluids at the pore scale. In this study, we test the feasibility of using the microfluidic technique to visualise the microbially induced carbonate precipitation (MICP) process. The experimental results obtained in this study show that the generation, evolution, and morphology of calcium carbonate, the effective product in MICP, can be clearly observed during the entire spatial and temporal range of the tests. Comparative tests with different testing variables, including the concentration of treatment solutions, activity of bacterial suspensions, and particle size, were also carried out. The results show that the influence of these variables on the treatment effects, such as the production rate of the reaction, spatial distribution of calcium carbonate, type and morphology of crystals, amount of ammonia gas produced, and presence/absence of clogging issues, can be visualised in microfluidic chips. The results presented in this paper prove that the microfluidic technique could be a helpful tool for unravelling the mechanisms of the MICP process at the pore scale and understanding the factors influencing the MICP process. [ABSTRACT FROM AUTHOR]

• NiFe 2 O 4 was prepared by a thermal decomposition process with various temperatures. • The micro-octahedral NiFe 2 O 4 grows along the dissolution‑recrystallization. • The FT-IR bands reveal the cation shifting from octahedral to tetrahedral structure. • The Eg (1.67 and 1.57 eV for 900 and 1,000 °C heating) refers 3A2g(3F) → 3T1g(3F). In this paper, NiFe 2 O 4 powders were prepared by a thermal decomposition process with various temperatures. The structural characteristic and intrinsic defect were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, and photoluminescence (PL). The morphology was investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). XRD pattern reveals the pure NiFe 2 O 4 phase as the calcination temperature of 900 and 1,000 °C. The calcination of 900 °C depicted the micro-octahedral structures with a smooth surface. The calculated hopping length and the FT-IR spectra reveal the cation shifting from octahedral to tetrahedral structure. The decreasing energy bandgap of NiFe 2 O 4 was investigated as the calcination temperature increased. The PL transition of 3A2g(3F) → 3T1g(3F) refers to the band-to-band emission. The structural characteristics, morphology, and defects were investigated and discussed in terms of phase, bonding vibration, crystal growth mechanism, emerging energy level and electron transition. [ABSTRACT FROM AUTHOR]

The Organic–inorganic hybrid compounds have attracted considerable attention for their scientific and technological potential according to their wide field application. In this paper, we describe the preparation of a new hybrid crystal, with the structural formula [C 6 H 9 N 2 ] 2 SnCl 6 , of which crystallographic, BFDH morphology, Hirshfeld and complex impedance spectroscopy have been studied and analyzed. The X-ray diffraction analysis revealed that the title compound crystallized in the centrosymmetric space group P2 1 /c of the monoclinic system. The powder XRD is used to confirm the phase purity of the sample and the crystalline nature of the powder. The [C 6 H 9 N 2 ] 2 SnCl 6 crystal morphologies are simulated from the Laue symmetry (2/m), and from the space group symmetry (P2 1 /c), which highlighted the effect of the screw axe 2 1 and the glide plane c in reducing the Importance morphology in the constructed model considering the space group symmetry. The intermolecular interactions studied using Hirshfeld surfaces showed the important contribution of H⋯Cl/Cl⋯H intercontacts (67.1 %) in the [C 6 H 9 N 2 ] 2 SnCl 6 crystal packing. The analysis of real and imaginary parts impedance spectra shows that the electrical properties are heavily dependent on frequency and temperature, indicating a relaxation phenomenon and semiconductor-type behavior. The Nyquist plot (-Z″ vs Z′) showed only one semicircular arc, representing the grain effect in the electrical conduction. The obtained results were analyzed by fitting the experimental data to an equivalent circuit model R/CPE/C. The Alternating current conductivity (σ AC) follows Jonscher's power law. The latter confirmed that the conduction is insured by the non-overlapping small polaron tunneling model (NSPT) model, which has been studied in depth. [ABSTRACT FROM AUTHOR]

Clay is a rich aluminosilicate resource with unique advantages as a raw material for zeolites production. However, synthesizing nanosized single-crystalline zeolites through a simple approach using clay remains a significant challenge. In this paper, acid-washed montmorillonite (MSR) was used to prepare nano-H-ZSM-5 single crystals with high crystallinity, uniform grain size and permeable straight pores under the induction of a small amount of organic template tetrapropylammonium hydroxide (TPAOH). Through temperature-staged treatment, the nucleation and growth process of zeolite were decoupled, ultimately achieving precise control over the size of the nano-single crystals. Mechanistic study showed that the low-temperature aging process produces smaller structural units which probably derived from the geopolymer topology of the clay, providing more active sites for zeolite nucleation, leading to the rapid crystallization during the high-temperature process. The porous structure promotes material diffusion, inhibits aromatic cycling and reduces carbon formation in the pores. The large specific surface area and nanoscale multilayer pore structure delay carbon accumulation and increase carbon holding capacity. These properties make nano-ZSM-5 single crystals an excellent choice for high olefin selectivity and long catalytic life in the methanol-to-olefin reaction. This synthetic route provides a general strategy for preparing nanosized zeolite single crystals from clay. [Display omitted] • High-quality nano-ZSM-5 single crystals with uniform morphology and good dispersion was obtained. • Nano-zeolite size can be precisely controlled by decoupling the nucleation and growth processes. • The "homogeneous silica–alumina" property of montmorillonite was crucial for ZSM-5 synthesis. • Nano-H-ZSM-5 has uniformly dispersed acid sites and effectively catalyzed the MTO reaction. • A general strategy broadens the idea for the application of clay in the field of zeolite synthesis. [ABSTRACT FROM AUTHOR]

The influence of organic additives on crystallization of polyolefins has not been paid enough attention due to the low dosage, but it may have a significant impact on the properties of polyolefins. In the paper, the organic amphiphilic molecules were introduced into high-density polyethylene (HDPE) through melt blending, and compared with neat HDPE. It is mainly discussed for the following aspects including analysis of crystal structure and morphology using wide-angle X-ray diffraction (WAXD) and polarized optical microscopy (POM), respectively; analysis of crystallinity, crystal rate, crystal growth and crystallization enthalpy, using the differential scanning calorimetry (DSC). The research indicates that the organic amphiphilic molecules may act as an internal lubricant. On the one hand, HDPE molecular chains are easy to fall off from crystal lattices, resulting in lagging crystallization peak, simultaneously reducing the interaction between HDPE molecules should induce the lower activation energy (ΔEm) to increase the crystallinity of HDPE. On the other hand, the amphiphilic molecules should be exclude from HDPE crystal to the amorphous area due to poor compatibility; thus, the HDPE/amphiphilic molecules blends, similar to neat HDPE, conduct homogeneous nucleation, and the growth of monocrystal performs the tendency of the zero-dimension to the two-dimension with increase in temperature of isothermal crystallization and decreasing cooling rate of non-isothermal crystallization. It is hoped that through these studies, people will pay more attention to the impact of organic additives on the performance of HDPE. [ABSTRACT FROM AUTHOR]

Revealing the internal structure of diamonds is key to understanding the general regularities of crystal growth and dissolution. This paper presents and summarizes data on the internal structure of diamonds of different morphological types, colors and defect-impurity composition. In order to provide a comprehensive explanation of the stages of diamond growth, crystals and plates were observed, and panchromatic cathodoluminescence and photoluminescence techniques were applied. This article considers the mechanism of tangential growth from existing surfaces (regeneration growth) as an intermediate stage between normal and tangential crystal growth. The regeneration growth is very fast due to the absence of the limiting stage-nucleation of a new atomic layer. Cuboid diamonds were refaceted to stepped octahedrons by the regeneration growth mechanism. A schematic model of crystal habit transformation due to regeneration growth explains the internal structure of crystals in connection with their morphology and thermal history. The main variants of regeneration stage and its morphological manifestations were demonstrated. Most diamonds pass through the regeneration stage, and in many cases, it was a stage of growth termination. [ABSTRACT FROM AUTHOR]

An aluminosilicate zeolite has a porous structure with openings comparable to the molecular size, which endows it with unique adsorptive and catalytic properties that are highly dependent on its chemical composition and crystal morphology. Thus, the precise control or rational design of zeolite's particle morphology has attracted much attention as it can greatly improve the adsorptive separation and catalytic properties by effectively adjusting the diffusion path of adsorbates, reactants and products. This paper reviews the recent progress made in the synthesis and application of zeolites with a specific crystal/particle morphology with emphasis on the control of the crystal size and facet exposure degree, oriented assembly of crystals, creation of hierarchical porous structures and synthesis of core–shell structures. It is shown that an appropriate decrease of the crystal size and/or an increase of the exposure degree of certain facets by adding seeds and optimizing the synthesis conditions enhances the catalytic stability and product selectivity in some reactions. This can also be achieved by introducing plenty of mesopores and/or macropores in zeolites as a result of significant alleviation of diffusion limitation. Assembly of zeolite crystals into membranes on porous substrates improves the adsorptive separation performance of zeolites, for e.g. alcohol/water mixture and xylene and butane isomers. Core–shell-structured composites with metal nanoparticles or subnanoparticles as the core and the zeolite, including its modified counterpart, as the shell show excellent catalytic performance in some hydrogenation, dehydrogenation and oxidation reactions. In addition, attempts to illustrate the relationship between zeolite's particle morphology and its catalytic performance are discussed and strategies for the rational design of zeolite's particle size and behavior are envisioned. [ABSTRACT FROM AUTHOR]

Summary: In this paper, a type of high‐performance nanostructure Fe2O3 (Fe2O3‐arc) is synthesized via a novel direct current electric arc method and employed as a sulfur‐wrapping matrix for lithium‐sulfur batteries. Scanning electron microscopy reveals Fe2O3‐arc has a granular morphology and the crystal size can be controlled below 100 nm. X‐ray diffraction patterns and Raman spectrums show that Fe2O3‐arc displays obvious confusion, but continues to have a typical Fe2O3 crystal structure with preferentially growing on the (110) crystal plane. After sulfur loading, stable physical entrapment and chemical interaction can be established between sulfur and Fe2O3‐arc matrix. The electrochemical test indicates the sulfur composite cathode with Fe2O3‐arc as matrix at the loading mass ratio to 1:3 has a stable and conventional sulfur electrochemical process. The initial discharge specific capacities can achieve 720.59, 653.79 and 540.32 mAh.g−1 at 0.1, 0.2 and 0.5 C current rates, respectively. And after 200 cycles, the capacity retention rate can be at 62.23%. [ABSTRACT FROM AUTHOR]

Inspired by inorganic oligomers, we herein develop a novel inorganic gel based on calcium oxalate oligomers, and the crystallization morphology has been studied initially in this paper. The prepared oligomer is translucent gel and can exist stably in ethanol, but in aqueous medium it will change from gel to powder. In the crystallization process, because of the volatile speed of solvent and capping agent TEA at different temperature, CaC2O4 oligomer gels (COOGs) exhibited distinct crystallization behavior and morphology. Compared with conventional inorganic crystallization, the crystallization process of the gel at room temperature shows a tendency to gradually extend to the inside of the gel. Moreover, the XRD pattern and SEM images shown that the COOGs achieved distinctly different crystal morphology under different temperature. These provide a preliminary research foundation for the crystallization behavior and control conditions of inorganic gels. [ABSTRACT FROM AUTHOR]

Cerium carbonate crystal morphology is predicted using density functional theory (DFT) simulations in this paper. In the nucleation phase, the ketone group in polyvinylpyrrolidone (PVP) will preferentially bind to Ce3+ to form complexes and provide heterogeneous nucleation sites for the system, prompting the nucleation of cerium carbonate crystals. In the growth stage, due to the adsorption of PVP, the probability of (120) crystal plane appearing in the equilibrium state is the greatest, resulting in the formation of hexagonal flake cerium carbonate crystals with (120) crystal plane as the oblique edge. Experimentally, hexagonal sheet cerium carbonate crystals were successfully prepared using PVP as a template agent. Therefore, DFT can be used to predict the morphology of cerium carbonate crystals, which not only elucidates the growth mechanism of cerium carbonate crystals, but also greatly reduces the experimental cost. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel truncated hexagonal pyramidal morphology of ZnO single crystals of ca. 1 μm. • Microwave irradiation on W/O emulsions containing ZnO precursor for the synthesis. • Crucial role of surfactants for asymmetric crystal growth along the c-axis. • SPED analysis and ABF-STEM imaging to reveal the shape asymmetry-crystallographic polarity correlation. This paper reports a discovery of novel morphological features of ZnO asymmetric micron-sized single crystals synthesized by microwave irradiation of W/O emulsions containing a Zn source in the inner aqueous phase. The influence of the zinc ion concentration on the size and shape is studied in detail. The morphological and structural properties show that the obtained ZnO powders are almost mono-dispersed ZnO single crystals with a novel morphology of truncated hexagonal pyramids ca. 1 μm in diameter. A scanning precession electron diffraction analysis reveals that the asymmetrically shaped ZnO single crystals thus obtained have a crystallographic c-axis perpendicular to the bottom hexagonal flat surfaces, and annular bright-field imaging indicates that the bottom surfaces are Zn-terminated ZnO(0001)-Zn polar faces. These new findings are led from a combination of well-controllable liquid-phase emulsion synthesis of the oxide powders and highly advanced atomic-resolution TEM imaging technique, suggesting for the first time a highly probable relationship between the polarity of the wurtzite-type crystal structure and the novel asymmetric morphology of the ZnO microcrystals obtained in this study. [ABSTRACT FROM AUTHOR]

During the preparation process of LiNi 0 · 6 Co 0 · 2 Mn 0 · 2 O 2 (NCM622) material via solid-phase method, the obtained NCM622 particle size is often inconsistent due to the inhomogeneous phase mixing, which makes the NCM622 material have low specific capacity and poor rate performance, and thus restrict the application of solid-phase method. In order to solve this problem and make full use of the advantages of solid-phase method, liquid-phase assisted mixing is used to replace the traditional mechanical mixing. At the same time, polyvinylpyrrolidone (PVP) is introduced to control the crystal morphology and particle size, thus a NCM622 material with excellent electrochemical energy storage performance has been prepared by the PVP modified liquid-phase assisted solid-state method in this paper. X-ray diffraction, scanning electron microscopy and Raman spectroscopy are used to characterize the morphology structure of the obtained materials. Their electrochemical energy storage performance is tested by program-controlled battery tester and electrochemical workstation after being assembled into button cells. The research results show that with the introduction of PVP, the particle size of the obtained material becomes smaller, the particle size distribution is more uniform, and the degree of cation mixing is further reduced. When the PVP adding amount is up to 1.6 wt %, the obtained material shows the best electrochemical performance: its first discharge specific capacity and coulomb efficiency are 183.19 mAh.g−1 and 88 % (0.1C), respectively. The capacity retention rate is 96.5 % after 100 cycles at 1C (half-cell system and laboratory conditions), which is comparable or better than those by other preparation methods, showing a good application prospect. [ABSTRACT FROM AUTHOR]

This paper focuses on the multi-dimensional performance analysis including the oxidation performance, crystal morphology, thermal properties, mechanical properties and dielectric behavior of the thermally aged extra high voltage XLPE submarine cable insulation. Results show that the antioxidation and thermal oxidative aging of XLPE insulation are coexisting and competing during the thermal degradation process. In the early stage of thermal degradation, the antioxidation of XLPE insulation is dominant resulting in the decline of the spacing between spherulites. In the later stage of thermal degradation, thermally oxidative aging of XLPE insulation is dominant, which leads to the damage of the crystalline morphology and the rapid generation of aging products. It is indicated that the mechanical strength of the XLPE insulation is mainly determined by its internal crystalline morphology, while the dielectric properties of the XLPE insulation are governed by the crystalline morphology, aging products and micro interface. With the thermal aging time extended, the breakdown strength of XLPE insulation first increases and then decreases, which is determined by its amorphous region and aging products. [ABSTRACT FROM AUTHOR]

• A pregelatinized starch-binding gypsum was prepared to mimic the historic binders. • The gypsum strength is enhanced by pregelatinized starch-binding gypsum structure at high w/c ratios. • The contact points stress enhancement promotes macro strength enhancement. • Hydrogen bonding plays a key role in constructing the pregelatinized starch–binding gypsum structures. Minimizing gypsum powder usage by increasing water to gypsum (w/c) ratios has both economic and environmental benefits. However, gypsum is limited in application by its poor mechanical strength at high w/c ratios. To enhance the strength of hardened gypsum at high w/c ratios, this paper proposes a pregelatinized starch–binding gypsum structure. The mechanical strength, working abilities, and microstructure of pregelatinized starch–binding gypsum samples at high w/c ratios were evaluated. And the micro-nano structure and enhancement mechanism of pregelatinized starch–modified gypsum was investigated. The results show that at high w/c ratios from 0.8 to 1.0, pregelatinized starch significantly improved the mechanical properties of gypsum, where the flexural and compressive strength of 3 d modified drying sample were 3.3 MPa and 6.6 MPa in comparison to pure gypsum samples tending to 0 MPa. Pregelatinized starch participates in the overlapping structure of gypsum crystals and bind to them without affecting the crystal structure and morphology of single particles. The nanostructure of modified contact points involved strong adsorption of pregelatinized starch onto the (1 2 0) face by hydrogen bonding, which enhanced binding adhesion at contact points. And pregelatinized starch effectively reduced separation of the (1 2 0) face under x– and z– tensile stretching, and slipping along the (0 1 0) face under y– tensile stretching. This paper presents a modification that enhances mechanical properties of gypsum at high w/c ratios, and provides deeper understanding of crystal overlapping mechanisms at the nanoscale. [ABSTRACT FROM AUTHOR]

BFDH crystal model morphology/stereoscopic projection, experimental (•••) calculated (—), and difference profile (—) of XRD pattern, and crystal structure of (CH 3) 4 N] 3 Bi 2 Cl 9. [Display omitted] The present paper reports on synthesis method, X-ray diffraction, DSC, Infrared and Raman spectroscopy studies carried out on [(CH 3) 4 N] 3 Bi 2 Cl 9. The structure of this hybrid material is refined by the Reitveld method in the space group P 6 3 / mmc (Z = 2), with unit cell parameters: a = 9.2581(2) Å, c = 21.9223(6) Å, V = 1627(1) Å3. It consists from isolated Bi 2 Cl 9 3- dimer anions composed of two distorted octahedra BiCl 6 3- sharing three chlorine atoms' face, and three disordered cations (CH 3) 4 N+, forming an organic–inorganic network. There are two disordered cations types: one cation totally disordered with N(1) atom placed in special Wyckoff positions (2b) of (-6m2) site symmetry, and Carbon atoms C1 and C 2 are three-fold disordered; the two others cations N(2) observed on special positions (4f) of site symmetry (3 m) are partially disordered, with C4 atom is three-fold disordered and C3 atom is ordered. The BFDH crystal morphology predicted from the Laue symmetry (6/mmm) gives hight faces characterized by two faces indices, with their center-to-plane distance d hkl and their growth rates. The simulated model from the space group symmetry (P 6 3 / mmc) gives three < h k l > faces indices, which highlights the screw axis 6 3 and the glide plane c effects in reducing the Importance morphology. The DSC analysis showed that the compound undergoes a reversible phase transition at 74 °C/69 °C (heating/cooling). The Infrared-Raman spectra are studied based by developing theoretical vibrations modes of cations and anions in the crystal; the study confirms the presence of (CH 3) 4 N+ cations and Bi 2 Cl 9 3- anions, which are linked by C H....Cl hydrogen bonding types. [ABSTRACT FROM AUTHOR]

1. Synthetic route of copolymer. 2. Possible mechanism of (C16-AM, C16-IM and C16-SM) for improving the fluidity of diesel oil at low temperature. [Display omitted] • Comb-like PAOs were synthesized from long-chain olefin and benzene containing olefin. • Comb-like PAOs can effectively improve the low temperature cold flow of diesel fuel. • The properties of synthetic PAOs and commercial PPDs were compared during oxidation. • The crystallization behaviors of Comb-like PAOs were studied. Pour point depressants (PPDs) represent an efficient and economical approach to enhance diesel's low-temperature fluidity, yet their efficacy is influenced by molecular structure and surfactant moieties. To achieve highly effective PPDs, a series of comb-structured poly-alpha-olefins (PAOs) were synthesized in this paper, designated as 1-hexadecene-styrene (C16-SM), 1-hexadecene- allyl benzene (C16-AM), and 1-hexadecene-indene (C16-IM). The copolymers' impact on diminishing diesel's solid point (SP) and cold filter plugging point (CFPP) was thoroughly investigated. Notably, with a 1-hexadecene to styrene monomer molar ratio of 20:1, the most favorable inhibitory effect of C16-SM was observed, exhibiting a reduction of 10 °C for CFPP and 30 °C for SP. Comparing C16-SM to commercial pour point depressants (CPPDs) after subjecting them to an accelerated oxidation test revealed that the C16-SM performance was more stable under oxidative conditions. To address stability and environmental pollution concerns associated with PPDs, this study aims to develop a stable, eco-friendly PAO PPD and assess the influence of various benzene ring-based monomers on diesel's cold fluidity in low-temperature conditions. Furthermore, a novel mechanism elucidating the change in crystal morphology and size by PAOs is proposed. [ABSTRACT FROM AUTHOR]

For further energy enhancement of water-reactive metal fuels, it is crucial to find aluminum composites that can react synchronously and quickly with multiple types of water (ice, steam, and water). In this paper, two graphite-based aluminum composites, aluminum/bismuth/graphite (Al/Bi/GI) and aluminum/bismuth/graphene nanosheets (Al/Bi/GE), were prepared. The morphology and crystal structure of the composites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The reactivity of Al/Bi/GI and Al/Bi/GE with water from 20 °C to 80 °C and ice at 0 °C and −15 °C was characterized using hydrogen generation properties. Their ignition and combustion properties in high-temperature water steam from 300 °C to 900 °C were also investigated. The results show that Al/Bi/GI and Al/Bi/GE composites prepared by ball milling have blocky and multilayered lamellar structures, respectively. That ball milling does not result in the formation of new alloys. The thickness of graphite material affects the reactivity of activated aluminum composites. The hydrogen generation rates of Al/Bi/GE in water and ice are much higher than that of Al/Bi/GI. The maximum hydrogen generation rates of Al/Bi/GE were 28.8 and 46.6 times higher than those of Al/Bi/GI in water at 20 °C and ice at −15 °C, respectively. In high-temperature water steam, the ignition temperature and ignition delay time of Al/Bi/GE are lower than those of Al/Bi/GI. Al/Bi/GE achieves a rapid reaction that can be synchronized with three forms of water and is expected to be applied to water-reactive metal fuel propellants. • Al/Bi/GI and Al/Bi/GE composites with different structures were prepared. • The multilayered lamellar structure of Al/Bi/GE has superior synergistic reactivity with different forms of water. • The MHGR of Al/Bi/GE on ice at −15 °C is 12.6 mL‧g-1‧s-1, 46.6 times higher than that of Al/Bi/GI. • Al/Bi/GE exhibits better combustion performance in high-temperature steam. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis, structure, BFDH crystal morphology, Raman and Infrared spectroscopic studies of three novel metal orthophosphate salts MII(Ga 0.5 Sb 0.5)(PO 4) 2 (MII= Sr, Pb, Ba), abbreviated [Sr], [Pb], [Ba]. The structures of these phases are refined from X-ray powder diffraction data by the Rietveld method. The yavapaiite [Ba] phase is monoclinic of C2/m space group [Z=2; a= 8.106(4) Å; b= 5.178(3) Å c= 7.806(1) Å, β=94.79(4)°, V= 327(1) Å3]. Its structure consists of layers, running along the (a, b) plane, and built up of corner-connected Ga(Sb)O 6 octahedra and PO 4 3− tetrahedra. The two isotypic phases [Sr]/[Pb] of distorted yavapaiite structure crystallize in the monoclinic C2/c space group (Z=4) with parameters: a=16.455(4)/16.622(7) Å; b=5.158(1)/5.163(2) Å c= 8.005(1)/8.067(3) Å; β=115.49(1)/114.85(2)°, V= 613(1)/628(5) Å3. Their structures consist of MO 10 (M= Sr, Pb), PO 4 3− tetrahedra and Sb(Ga)O 6 octahedra. In [Pb] phase, the Pb is surrounded by eight oxygen atoms (Pb-O: 2.65-2.77 Å) and two oxygen atoms forming abnormal bond distances Pb-O(4) [3.447(3)Å]. The BFDH crystal morphology predicts hight (h k l) facets for each compound, the center-to-plane distances d hkl are slightly strong in the distorted Yavapaiite [Pb/Sr] rather than in [Ba]. The IR and Raman study is performed based on theoretical group analysis considering C s site symmetry of PO 4 3− groups in [Ba], and C i symmetry in [Pb]/[Sr] phases. The assignment and discussion of the observed bands were done by comparison with other yavapaiite materials. The UV–visible investigation reveals direct optical gap energies of values 4.16 eV for [Ba] and 4.24 eV for [Sr], indicating a semi-conducting nature of the prepared materials. Crystal structures, UV absorbance, and and Tauc Plots (F(R)hν)1/2 of versus hν of AII(Sb 0.5 Fe 0.5)(PO 4) 2 (AII = Ba, Pb, Sr) compounds. [Display omitted] • Novel A(Sb 0.5 Ga 0.5)(PO 4) 2 (A= Ba, Pb, Sr) crystal structures are determined and discussed. • The BFDH morphology of [Ba] and [Sr] are simulated from parametres and Laue symmetry of these crystals. • Theoretical analyses are made in assignment of IR and Raman bands for the three phases. • UV–visible absorptions indicate a semi-conducting nature of the synthetised materials. [ABSTRACT FROM AUTHOR]