Production Of Crystals Research Articles

On the Diversity and Formation Modes of Martian Minerals

AbstractA systematic survey of 161 known and postulated minerals originating on Mars points to 20 different mineral‐forming processes (paragenetic modes), which are a subset of formation modes observed on Earth. The earliest martian minerals, as on Earth, were primary phases from mafic igneous rocks and their ultramafic cumulates. Subsequent primary igneous minerals were associated with products of limited fractional crystallization, including alkaline and quartz‐normative lithologies. Significant mineral diversification occurred via precipitation of primary phases from aqueous and atmospheric fluids, including authigenesis, hydrothermal and cryogenic precipitation, and evaporites, including freeze drying during eras of low atmospheric pressures. In particular, hydrothermal mineral formation associated with both volcanic fluids and sustained hydrothermal activity in impact fracture zones may have triggered significant mineral diversification, though as yet undocumented. At least 65 such primary minerals have been identified by flown missions to Mars and from martian meteorites. A host of secondary martian minerals were produced by near‐surface processes related to water/rock interactions, including hydration/dehydration, oxidation/reduction, serpentinization, metasomatism, and a variety of diagenetic alterations. Additional mineral diversity resulted from metamorphic events, including thermal and shock metamorphism, lightning, and bolide impacts. However, several dominant sources of mineral diversity on Earth, including (a) extensive fluid/rock interactions and element concentration associated with plate tectonics; (b) high‐pressure regional metamorphism associated with plate tectonics; and (c) biologically mediated mineralization—are not known to be in play on Mars. Consequently, we estimate the total mineral diversity of Mars to be an order of magnitude smaller than on Earth.

Extensive oxidizing events recorded by peridotite mantle xenoliths from the Hyblean Plateau: Evidence from combined measurements of ferric iron in spinel with noble gases and fluid inclusions chemistry in olivine

The study of the oxidation state of lithospheric mantle-derived rocks allows modelling the deep cycle of volatiles (e.g., C, H, O, N and S) in the Earth's interior, which in turn plays a role in magma genesis, metasomatism and volcanic degassing. At the oxygen fugacity (i.e., fO2) recorded by residual abyssal peridotites, volatile elements like carbon are predicted to be in the immobile form of graphite. However, the compilation of the redox state of worldwide-distributed continental xenoliths shows evidence of their oxidation and refertilization through time by deeply formed subduction-related metasomatic fluids. The analyses of fluid inclusions in mantle-derived minerals like olivine (or pyroxenes) represent a snapshot of the volatile circulation in depth, whose noble gases signature (He, Ar, Ne) is used to identify their possible source. This study aims to reconstruct the origin of mantle metasomatism underneath the Hyblean Plateau (Sicily, Italy) and its redox history through the investigation of spinel-peridotite nodules, combining fO2 estimates with noble gases and fluid inclusions chemistry from hand-picked olivine grains. We analyzed eight mantle xenoliths classified as spinel lherzolites and spinel harzburgites from the Valle Guffari (Hyblean Plateau, Sicily). The calculated logfO2 is higher than that of most cratonic xenoliths worldwide ranging between 0.28 and 1.27 log units above to the fayalite-magnetite-quartz (FMQ) reference buffer. Micro-Raman measurements on olivine grains with dendritic trails of (metasomatic) fluid inclusions reveal an assemblage made of Mg-Ca carbonates ± sulfide ± elemental sulfur ± CO2 in the most reduced sample, and Mg-Ca carbonates ± sulfates ± CO2 in the most oxidized sample, the latter associated with a silicate glass and (secondary) hydrous phases. Both assemblages are taken as evidence of the product of crystallization of deeply originated volatile-bearing silicate melts. Analyses of He, Ar, and Ne in olivine grains confirm the evidence of a mantle source reworked by metasomatic processes. Our data suggest that an initially residual Hyblean lithospheric mantle was affected by extensive oxidizing events at several depths caused by the interaction with slab-derived CO2-rich silicate metasomatic liquids.

Growth of TiO2 single crystals by the Verneuil method at different gas flow ratio

The oxygen-rich atmosphere is a prerequisite for the preparation of high-quality TiO2 single crystals using the Verneuil method. However, too much oxygen will bring down the temperature of the growing chamber, so the key to growing high-quality TiO2 single crystals is to ensure that the temperature distribution is stable and that the heat in the growth chamber is in equilibrium. In this paper, TiO2 single crystals were prepared by the Verneuil method under different gas flow ratio. Due to the inability to obtain a stable temperature field, the crystals produced at the hydrogen-to-oxygen ratios of 1.4 and 1.8 both had substantial dislocation densities and low optical transmittance. The heat in the growth chamber reaches equilibrium and the temperature distribution is steady-state when the hydrogen-to-oxygen ratio is 1.6. The FWHM of the crystal obtained under this condition is 0.02334°, the transmittance is nearly 70 %, and the etch pit density is only 6.21 × 104 cm−2. This work is a major boost to the industrial production of rutile crystals.

Strength formation mechanism and curing system optimization of low-carbon cementitious materials prepared by synergistic activation of multiple alkaline solid wastes

Lack of proper disposal of carbide slag (CS), soda residue (SR), and red mud (RM), which are alkaline solid wastes released from the production of acetylene, soda ash, and alumina, respectively, adversely affects the environment. This study synthesized a new low-carbon cementitious material using CS-SR-RM-fly ash (FA) as raw material and optimized its curing method.The influence of raw material composition and various curing systems on the mechanical properties and microstructure of specimens was analyzed using compressive strength, chloride ion consolidation, XRD, FTIR, and SEM-EDS. The optimum ratio of CS:SR:RM:FA was determined to be 2:1:4:3, and the compressive strength of 3/28 d at room temperature (RT) sealed curing reached 10.7/22.1 MPa. The alkaline environment created by CS-SR-RM facilitated the decomposition of active components in FA and RM, contributing to the formation of a stable three-dimensional network comprising N-A-S-H gel, C-(A)-S-H gel, and Friedel's salt crystal product. High-temperature (HT) curing at 80 °C for 8 h significantly enhanced early strength, with strength growth rates of up to 147.7/29.9% compared with RT sealed curing at 3/28 d. HT curing promoted the rapid and steady growth of hydration products, resulting in increased structural compactness and improved strength. The present study offers suggestions for reducing the environmental pollution caused by alkaline solid waste and developing new resource utilization means.

A study on self-shielding effect of CaCO3 in cable pyrolysis using gas product analysis and PSO optimization

This paper investigates the self-shielding mechanism of CaCO3 during the pyrolysis of PVC-CaCO3 based cable. Previous studies have focused on HCl adsorption by CaCO3, neglecting the self-shielding effect. In this paper, thermogravimetric-infrared analyzer, pyrolysis gas chromatography-mass spectrometer and particle swarm optimization (PSO) algorithm are used to investigate the self-shielding mechanism. The results show a three-stage pyrolysis process. In the first stage, CaCO3 weakens the autocatalytic decomposition of PVC by absorbing HCl in the solid phase. The 3rd Avrami Erofeev model was obtained by PSO, representing the production of CaCl2 crystals. The second stage demonstrates self-shielding due to a reduction in solid-phase porosity. CaCO3 encapsulation inhibits the pyrolysis of PVC resulting in macromolecular intermediates. The 3rd order-based model was obtained by PSO, with a lower pyrolysis reaction rate compared to pure PVC. In the third stage, the stability of Cl in the solid phase is weakened at high temperatures, which converts the Cl to the gas phase in the form of chlorinated hydrocarbons, leading to the failure of self-shielding effect of CaCO3. The 2nd order-based model was obtained by PSO, which is considered as a result of the solid phase reactions instead of pyrolysis.

A new genus Neobelonopsis and two new species of Trichobelonium (Helotiales, Ascomycota) discovered mainly from poaceous grasses native to Asia in Japan.

Mollisioid fungi, represented by Mollisia (Fr.) P. Karst., are characterized by soft, sessile apothecia with globose, dark-celled excipula, hyaline ascospores, and worldwide distribution in temperate regions. Their generic and species delimitation is difficult due to the lack of distinct features, and studies based on DNA sequences are urgently required. Two genera of mollisioid fungi, Belonopsis and Trichobelonium, comprise relatively few species and are recognized by (0-)1-3-septate ascospores, medullary excipulum composed of loosely interwoven hyphae, and calcium oxalate crystals in the excipulum. Specimens of undescribed species that are morphologically assignable to Belonopsis or Trichobelonium were collected from various sites in Japan and their assignment to the proper genera was attempted. According to a molecular phylogenetic analysis involving members of Mollisiaceae based on concatenated sequences of ITS, LSU, and RPB1, eight taxonomic entities were placed in a strongly supported single clade with Mollisiadiesbachiana, separated from the type species of Belonopsis, B.excelsior. A new genus Neobelonopsis was thus proposed to accommodate the undescribed species. In this study, eight new species of Neobelonopsis and two new species of Trichobelonium were described. A new combination was also proposed for M.diesbachiana. The generic distinction of Neobelonopsis and Trichobelonium was supported by molecular analysis. Some additional characteristics to delimit Trichobelonium were identified, such as the presence of anchoring hyphae between the base of the apothecium and subiculum, and the production of abundant crystals and soluble pigments on the colonies. Derivative species of Neobelonopsis were found to have multi-septa in ascospores.

Fluoride Removal and Recovery from Water Using Reverse Osmosis and Osmotic Membrane Crystallization

Fluoride is a concern for human health at high concentrations, but it is also a valuable compound with multiple applications. Thus, having a system that gives the opportunity to remove and recover this valuable element from water is highly interesting. Reverse osmosis (RO) is a promising technology in the removal of fluoride from water. Nevertheless, the residual retentate highly concentrated in fluoride is still a concern. The aim of this study was to evaluate the performance of an integrated process consisting of RO and membrane crystallization to remove fluoride from water and to recover it as a pure fluoride salt. Pure water permeability and fluoride rejection of a commercial RO membrane was tested under different conditions. In addition, the performance of an osmotic membrane crystallization setup was evaluated, considering the effect caused by the flow rates and the concentration of both the feed and the osmotic solution on the mass transfer coefficient. The crystallization process allowed the production of pure NaF crystals with octahedral morphology with a face-centered cubic crystal system.

Ecological and hygienic assessment of soils on the content of heavy metals and arsenic in an industrial city with glass production

Introduction. The paper presents the results of a study on assessing the level of soil contamination with heavy metals and arsenic in a city with a long-term glass production.
 Materials and methods. The object of the study is the soil cover of the city of Gus-Khrustalny, widely known for the products that are produced at its enterprises. The city-forming industry, the mention of which begins in the second half of the 18th century, is the production of glass and crystal.
 Results. The presence of polyelement pollution of the soil cover of the city was established, which is probably associated with the specifics and duration of the functioning of the glass industry. The priority pollutants of urban soil are primarily those belonging to the first hazard class, Zn, Pb, and As. The maximum levels of pollution were recorded in the industrial urbanozems, the minimum – in the landscape and recreational zone. An extremely dangerous chemical contamination of the soil in terms of the total indicator was revealed on the territory of the currently non-functioning part of the glass plant, which in fact is a local technogenic lithogeochemical anomaly. An assessment of the level of chemical contamination of soils as an indicator of an adverse impact on the health of the population showed most of them to live in the zone of moderately hazardous or hazardous soil categories.
 Limitations. The limitations of the study are associated with one-time sampling and a small number of reference areas, which limits the possibility of a broader interpretation of the data obtained. 
 Conclusion. To justify measures to reduce the risk to the environment and health of the population living here, it is necessary to manage constant environmental and hygienic monitoring of the territory. To reduce soil pollution in the city, there are required the modernization of industrial enterprises and the creation of expanded sanitary protection zones around them. It is necessary to carry out measures to detoxify contaminated soilsusing modern methods, primarily biological treatment as phytoremediation, phytorecultivation.

Large-Scale Production and Optical Properties of a High-Quality SnS2 Single Crystal Grown Using the Chemical Vapor Transportation Method

The scientific community believes that high-quality, bulk layered, semiconducting single crystals are crucial for producing two-dimensional (2D) nanosheets. This has a significant impact on current cutting-edge science in the development of next-generation electrical and optoelectronic devices. To meet this ever-increasing demand, efforts have been made to manufacture high-quality SnS2 single crystals utilizing low-cost CVT (chemical vapor transportation) technology, which allows for large-scale crystal production. Based on the chemical reaction that occurs throughout the CVT process, a viable mechanism for SnS2 growth is postulated in this paper. Optical, XRD with Le Bail fitting, TEM, and SEM are used to validate the quality, phase, gross structural/microstructural analyses, and morphology of SnS2 single crystals. Furthermore, Raman, TXRF, XPS, UV–Vis, and PL spectroscopy are used to corroborate the quality of the SnS2 single crystals, as well as the proposed energy level diagram for indirect transition in the bulk SnS2 single crystals. As a result, the suggested method provides a cost-effective method for growing high-quality SnS2 single crystals, which could lead to a new alternative resource for producing 2D SnS2 nanosheets, which are in great demand for designing next-generation optoelectronic and quantum devices.

The magmatic-hydrothermal transition in P-rich pegmatitic melts: Crystal-melt-fluid interactions recorded by phosphate minerals

Rare-element pegmatites are the crystallization product of melts strongly enriched in incompatible elements. Some of these elements, e.g., Li, B, P, F, and H2O, function as melt structure modifiers, allowing such melts to reach unusually low crystallization temperatures and regulating the saturation of aqueous-carbonic fluids from the melt. However, the timing of fluid saturation is highly debated, and the processes that mark the magmatic-hydrothermal transition in rare-element pegmatites are still elusive. The crystallization sequence of phosphate minerals can be used to assess the timing and nature of fluid-related processes in pegmatitic systems. In the Buranga pegmatite, western Rwanda, magmatic phosphates are replaced by (hydrous) alkali-rich phosphates and later by strongly hydrated phosphates as the dike cools. This reaction series indicates a disequilibrium in the crystal-melt-fluid system and records complex fluid-rock interactions during dike consolidation. This contribution compares these interactions with the fluid record preserved in fluid inclusions in the main phosphates of the crystallization sequence. Three major fluid inclusion types are observed, aqueous-carbonic (mostly-two-phase, L-V), carbonic-aqueous (two-phase, V-L, or three-phase, L-L-V), and crystal-rich inclusions (multiphase, L-V-Solids). Crystal-rich fluid inclusions in trolleite [Al4(PO4)3(OH)3], the last primary phosphate to precipitate from the melt, show a paragenesis of solid phases similar to the secondary phosphates observed in the dike. LA-ICPMS analyses of individual fluid inclusions show high concentrations of Na and K, with some content of Li, Rb, Cs, B, Fe, and Mn in the fluid. A similar composition is present in all inclusion types within the same mineral. Crystal-rich fluid inclusions demonstrate that during the magmatic-hydrothermal transition, primary phosphates react with the fluid in the presence of melt to generate secondary phosphates. No evidence of external fluid sources has been observed during the magmatic-hydrothermal transition. The fluid inclusion record shows that the fluid salinity is kept constant due to fluid-mineral interactions and corroborates the hypothesis that fluid-soluble elements are internally remobilized in the melt-crystal-fluid system during the magmatic-hydrothermal stage. These interpretations have implications for the general evolution of P-rich pegmatitic melts and the mineralization of Nb and Ta in these systems.

Looking for an Optimal Composition of Nickel-Based Catalysts for CO2 Methanation

A detailed critical analysis of the scientific literature data concerning catalysts for CO2 methanation based on nickel supported over oxides was performed. According to the obtained information, it seems that an ionic support is necessary to allow a good nickel dispersion to produce very small nickel metal particles. Such small metal particles result in being very active toward methanation, limiting the production of carbonaceous materials. The use of support and/or surface additives gives rise to medium surface basicity, allowing medium-strong adsorption of CO2, and it is also advisable to increase the reaction rate. A medium nickel loading would allow the free support geometric surface to be covered densely by small nickel metal particles without the production of larger Ni crystals. It is also advisable to work at temperatures where Ni(CO)4 formation is not possible (e.g., >573 K). The promising properties of systems based on doped Ni/Al2O3, doped with basic and re-active oxides such as MnOx or/and CeO2, and those based on Ni/CeO2 were underlined.

Solubility, Crystallization, and Characterization of Cytidine Sulfate.

Cytidine is an important kind of nucleoside that can be applied to drug development and food industry. Cytidine sulfate is one of its popular forms, which is promising as a medicinal intermediate, especially in antiviral and antitumor drugs. Product refining is the key point of industrial development, and crystallization is a significant way of refining. In this work, the solubility of cytidine sulfate in pure water from 278.15 to 328.15 K and in water-ethanol binary solvents at 298.15 K was measured by the UV spectroscopic method. The solubility data were correlated with temperature and solvent composition using the modified Apelblat, van't Hoff, and CNIBS/R-K equations. On this basis, we investigated and compared three crystallization processes, and the coupling method was developed to prepare crystals with a large particle size, concentrated distribution, and high yield and packing density. In addition, the structure and stability of the products were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and dynamic vapor sorption analysis. It was found that cytidine sulfate has only one crystal form in our research process, and the product of coupling crystallization is stable and favorable for industrial development.

Influence of support properties on selective oxidation of 2-methylnaphthalene on vanadia-molybdena based catalyst

In this work, the catalytic performance of vanadia-molybdena loaded on TiO2, MgO, ZSM-5, NaY and Mordenite was investigated in the selective oxidation of 2-methylnaphthalene (2-MN) to 2-naphthaldehyde (2-NA). Results show that strong interactions between supports (TiO2, ZSM-5) and active components can promote the dispersion of active component. Monolayer VOx and MoOx are the main form on the catalyst surface, which is beneficial to the 2-NA selectivity. However, the corresponding weak interactions between Mordenite and active components may lead to the production of oxide crystals and the separation of active components, thus reducing the 2-NA selectivity. Due to the high Na content, new crystal NaVMoO6 forms on the NaY surface, which is inactive in the reaction. For V-Mo/TiO2, V and Mo can be inserted into the TiO2 lattice, changing the electronic structures of active components and support and improving the activity of surface oxygen species. This investigation highlights an important consideration on supports properties when designing supported catalysts.

A Liquid and Waste-free Method for Preparing Single Crystal Positive Electrode Materials for Li-ion Batteries

Nickel-rich layered positive electrode materials are normally made by a “co-precipitation-sintering” method. Mixed transition metal hydroxides called “precursors” are prepared by co-precipitation to ensure homogeneous cation mixing at the atomic level and to create spherical particles which ensure high-performance poly-crystalline materials. Single crystal materials, which show better capacity retention in long-term cycling can be made from the same mixed transition metal hydroxide precursors by sintering at a higher temperature which inevitably destroys the spherical morphology present in the initial precursors. Here we describe a method for single crystal positive electrode material production which we call “all-dry synthesis” since it does not require the use of any liquid and creates no waste unlike the co-precipitation method. The exemplary reaction between Ni, MnCO3, and LiOH·H2O was studied in situ by synchrotron XRD in order to define a proper heating scheme for the all-dry process. The crystal structure, particle morphology, surface residual impurities, and electrochemical performance of materials prepared by the “all-dry synthesis” method are equivalent to or even better than those of materials made using a conventional co-precipitation method.

Antibacterial nanocomposite of chitosan/silver nanocrystals/graphene oxide (ChAgG) development for its potential use in bioactive wound dressings

An adequate wound dressing reduces time of healing, provides cost-effective care, thereby improving patients’ quality life. An antimicrobial bioactivity is always desired, for that reason, the objective of this work is to design an antimicrobial nanocomposite of chitosan/silver nanocrystals/graphene oxide (ChAgG). ChAgG nanostructured composite material is composed of chitosan from corn (Ch), and silver nanocrystals from garlic (Allium sativum). The nanocomposite obtained is the result of a series of experiments combining the graphene oxide (GrOx) with two members of the Amaryllidaceae family; garlic and onion (Allium cebae), which contain different sulfur materials. The characterization arrays confirmed the successful production of silver crystal, graphene oxidation and the blending of both components. The role of the chitosan as a binder between graphene and silver nanocrystals is proved. Moreover, the study discusses garlic as an optimal source that permits the synthesis of silver nanocrystals (AgNCs) (⁓ 2 to 10 nm) with better thermal and crystallinity properties. It was also confirmed the successful production of the ChAgG nanocomposite. Escherichia coli and Staphylococcus aureus were used to demonstrate the antibacterial bioactivity and L-929 fibroblast cells were utilized to visualize their biocompatibility. The proposed ChAgG nanomaterial will be useful for functionalizing specific fiber network that represents current challenging research in the fabrication of bioactive wound dressings.

Phase Equilibrium and Crystallization Process of the Ternary System KCl-(NH2)2CO-H2O at Different Temperatures

The phase equilibriums of the ternary system KCl-(NH2)2CO-H2O at 303.15 K, 323.15 K, 333.15 K, and 343.15 K were studied using the isothermal dissolution equilibrium method, in which the composition of equilibrium solid phase was determined by Schreinemaker’s wet residue method and X-ray diffraction (XRD) method. It was found that the ternary system is a simple cosaturated system, without the formation of neither double salt nor solid solution. Wilson and NRTL models were employed to correlate in the solubility data of the system at experimental temperatures. The maximum values of RAD and RMSD of the Wilson model were 2.18 × 10−2 and 0.83 and those of the NRTL model were 1.69 × 10−2 and 0.40, respectively. The two models were utilized to forecast solubility data at various temperatures, and the obtained outcomes were in line with the literature data. Based on the experimental solubility data at 343.15 K, the cooling crystallization process of the system was monitored online by focused beam reflectance measurement (FBRM) and particle video microscope (PVM). The crystal products were characterized by XRD, scanning electron microscope (SEM), and energy dispersive spectrometry (EDS). The results showed that the precipitation of (NH2)2CO occurred during the crystallization process, and this was followed by KCl. KCl was formed on the surface of (NH2)2CO crystal. The crystal was a simple mixture containing KCl and (NH2)2CO.

Volumetric Nanocrystal Lattice Reconstruction through Dynamic Metal Complex Docking.

Vacancies pose a major challenge in the production of high-quality crystals, particularly at the nanoscale. To address this problem, we report a convenient strategy that involves volumetric lattice reconstruction and dynamic metal complex docking to produce ultrasmall (10 nm) and bright core-shell upconversion nanoparticles (UCNPs). This strategy involves the formation of lanthanide ion-oleic acid complexes during postannealing in solution, which effectively removes vacancies in nanocrystals. The removal of vacancies restricts the diffusion of lanthanide sensitizers and emitters within the core, thus minimizing surface quenching. Our volumetric lattice reconstruction strategy provides fundamental insights into lattice engineering and presents a general strategy for purifying functional nanocrystals for applications in fields such as single-molecule tracking, quantum optics, energy conversion, and others.

Study of lactose crystallization in vibrated bed using high and specific seeding

Lactose crystallization is an operation addressed in several scientific studies and used in dairy industries to obtain a final product with high purity, even from impure solutions. Vibration agitation becomes a relevant factor in promoting mass transfer solution-crystalline surface and minimizing breakages and ruptures in the latter. The crystallization step can be triggered by the seeding of particles (fines) of the same substance to be crystallized, promoting greater control and uniform particle size. The objective of this work was to study the operation of crystallization of lactose in a vibrated bed, using high seeding with controlled structure and size (specific). A central composite design with subsequent optimization was used as a statistical tool. Optimum operating levels were obtained, which returned responses of average productivity of 119.0 ± 2.1% and average diameter of 8.06 ± 0.22×10-6 m, also promoting an increase in the average size of crystallization products (growth of 43.6%), which was not observed in the previous study such as seeding with milled commercial lactose.

Eco-friendly carbon dots induced thermally stable vertical alignment in planar anchored nematic liquid crystal

We report the induction of thermally stable vertical alignment of nematic liquid crystal, 4-cyano-4′-pentylbiphenyl (5CB), in a planar anchored cell by doping with eco-friendly carbon dots (CDs, diameter ∼7–8 nm), investigated through thermal, optical, electro-optical and dielectric spectroscopic techniques. Cross-polarized optical textures and voltage-dependent optical transmission measurements demonstrate the induction of vertical alignment of CDs-5CB composites with concentration of CDs (≥0.3 wt%) in planar anchored sample cells at room temperature. Moreover, the frequency-bias-concentration dependent dielectric studies done also confirms the induced vertical alignment. For instance, the relative dielectric permittivity measured on CDs-5CB composites (CDs ≥ 0.3 wt%) in planar anchored sample cells at bias voltage of 0 V and 30 V DC are almost equal and the presence of a short axis molecular relaxation at 0 V confirms the induced vertical alignment. The concentration and bias dependence of short axis molecular relaxation frequency are also discussed. It appears that CDs are able to align 5CB molecules vertically at the substrate by overcoming the pre-existing planar anchoring. Such induced alignment would propagate through the bulk of sample cell because of the coherence length of nematic liquid crystal molecules and eventually the whole sample obtains vertical alignment. We anticipate the great utility of these composites in the production of eco-friendly liquid crystal displays and other photonic devices, sensors, etc.

Enriched high purity germanium detectors for the LEGEND-200 experiment: purification and characterization by quadrupole and high resolution inductively coupled plasma mass spectrometry (ICP-MS)

LEGEND-200 (Large Enriched Germanium Experiment for Neutrinoless ββ Decay) is a physics experiment at the Gran Sasso National Laboratories (LNGS) in Italy searching for neutrinoless double beta (0υββ) decay of 76Ge using enriched high purity germanium (HPGe) detectors with a total mass of about 200 kg.During the production of germanium crystals, especially during the crystal cutting, a fraction of the enriched germanium remains as metal residues. To reuse these residual materials again for crystal growing, they must be efficiently purified. A special plant was built to purify and convert Ge metal to GeO2.Quadrupole ICP-MS (Q-ICP-MS) and High Resolution ICP-MS (HR-ICP-MS) were used to characterize the starting materials, reaction and final products. The results of the analyses are presented here.