Crystal Arrangement Research Articles

Crystal superlattices for versatile and sensitive quantum spectroscopy.

Nonlinear interferometers with quantum correlated photons have been demonstrated to improve optical characterization and metrology. These interferometers can be used in gas spectroscopy, which is of particular interest for monitoring greenhouse gas emissions, breath analysis and industrial applications. Here, we show that gas spectroscopy can be further enhanced via the deployment of crystal superlattices. This is a cascaded arrangement of nonlinear crystals forming interferometers, allowing the sensitivity to scale with the number of nonlinear elements. In particular, the enhanced sensitivity is observed via the maximum intensity of interference fringes that scales with low concentration of infrared absorbers, while for high concentration the sensitivity is better in interferometric visibility measurements. Thus, a superlattice acts as a versatile gas sensor since it can operate by measuring different observables, which are relevant to practical applications. We believe that our approach offers a compelling path towards further enhancements for quantum metrology and imaging using nonlinear interferometers with correlated photons.

Multidisciplinary approach to the study of large-format oil paintings

Cultural heritage has become a keystone for comprehending our society, as it represents and reflects our origins, passions, beliefs and traditions. Furthermore, it provides fundamental information about specific temporary spaces, materials’ availability, technology, artist’s intention, and site weather conditions. Our aim was to develop a multidisciplinary approach with a main focus on investigating two Italian large-format paintings located in highly diverse environments such as the National Theater of Costa Rica. We monitored environmental conditions and quantified fungal aerial spores. Then, we determined regions of possible biodeterioration with the software MicroorganismPattern and used the software PigmentArrangement to elucidate the apparent colour of the paintings based on distribution and arrangement of the pigment crystals. Finally, we characterized eight genera of calcareous nannofossils found in the ground layers of the artwork. The former Men’s Canteen at the National Theater of Costa Rica presented a mean air temperature of 23.5 ^{circ }C, a relative humidity of 72.7% and a concentration of CO_{2} of 570 ppm. The fungal aerial concentration was 1776 spores/m^{3}. The software MicroorganismPattern identified 32 sampling regions, out of which 11 were positive for microbial contamination. The software PigmentArrangement determined that the blue crystals (ultramarine pigment) had the shortest distances between themselves (29 upmum). Finally, the nanofossils identified enabled us to restrict the age of the material to a biostratigraphic interval ranging from Coniacian to Maastricthian ages. By using a multidisciplinary approach we were able to explore the diptych, suggest a set of minimally invasive perspectives in tropical environments to be used worldwide and obtain key information about the artist’s artistic process, materials used along with better understand its state of conservation.

Enamel Structure Defects in Kdf1 Missense Mutation Knock-in Mice.

The Keratinocyte differentiation factor 1 (KDF1) is reported to take part in tooth formation in humans, but the dental phenotype of Kdf1 mutant mice has not been understood. Additionally, the role of the KDF1 gene in dental hard tissue development is rarely known. In this study, we constructed a Kdf1 missense mutation knock-in mouse model through CRISPR/Cas9 gene-editing technology. Enamel samples from wildtypes (WT) and Kdf1 homozygous mutants (HO) were examined using micro-computed tomography (micro-CT), scanning electron microscopy (SEM), an atomic force microscope (AFM) and Raman microspectroscopy. The results showed that a novel Kdf1 missense mutation (c. 908G>C, p.R303P) knock-in mice model was constructed successfully. The enamel of HO mice incisors appeared chalky and defective, exposing the rough interior of the inner enamel and dentin. Micro-CT showed that HO mice had lower volume and mineral density in their tooth enamel. In addition, declined thickness was found in the unerupted enamel layer of incisors in the HO mice. Using SEM and AFM, it was found that enamel prisms in HO mice enamel were abnormally and variously shaped with loose decussating crystal arrangement, meanwhile the enamel rods were partially fused and collapsed, accompanied by large gaps. Furthermore, misshapen nanofibrous apatites were disorderly combined with each other. Raman microspectroscopy revealed a compromised degree of order within the crystals in the enamel after the Kdf1 mutation. To conclude, we identified enamel structure defects in the Kdf1 missense mutation knock-in mice, which displayed fragmentary appearance, abnormally shaped prism structure, decreased mineral density, altered crystal ordering degree and chemical composition of the enamel layer. This may support the potential role of the KDF1 gene in the natural development of enamel.

Pore topology analysis in porous molecular systems.

Porous molecular materials are constructed from molecules that assemble in the solid-state such that there are cavities or an interconnected pore network. It is challenging to control the assembly of these systems, as the interactions between the molecules are generally weak, and subtle changes in the molecular structure can lead to vastly different intermolecular interactions and subsequently different crystal packing arrangements. Similarly, the use of different solvents for crystallization, or the introduction of solvent vapour, can result in different polymorphs and pore networks being formed. It is difficult to uniquely describe the pore networks formed, and thus we analyse 1033 crystal structures of porous molecular systems to determine the underlying topology of their void spaces and potential guest diffusion networks. Material-agnostic topology definitions are applied. We use the underlying topological nets to examine whether it is possible to apply isoreticular design principles to porous molecular materials. Overall, our automatic analysis of a large dataset gives a general insight into the relationships between molecular topologies and the topological nets of their pore network. We show that while porous molecular systems tend to pack similarly to non-porous molecules, the topologies of their pore distributions resemble those of more prominent porous materials, such as metal-organic frameworks and covalent organic frameworks.

Ordered Arrangement of Bent and Faceted Single Crystals of Poly(vinylidene Fluoride)

Ordered Arrangement of Bent and Faceted Single Crystals of Poly(vinylidene Fluoride)

Dielectric Spectroscopy of Calcium Titanate Processed by Spark Plasma Sintering.

Calcium titanate (CaTiO3) powder was compacted by spark plasma sintering (SPS). The resulting products were subjected to the phase stability study and dielectric characterization. The change in temperature of SPS between 1100 °C and 1250 °C had a clear and straightforward effect on density, porosity, relative permittivity, loss tangent, and DC resistivity. Since the SPS itself introduces certain oxygen deficiency into Ti-perovskites, all samples were annealed after SPS. However, this post-processing did not mask the effects of the SPS regime. Optical reflectance measurements were completed to compare and quantify the sample coloration and support the dielectric results with corresponding optical band gap estimations. Subtle changes in the CaTiO3 crystal lattice arrangement, completed between 1150 °C and 1250 °C and documented in the literature for conventionally sintered samples, could not be confirmed for SPS-prepared calcium titanate. The novelty of this research work is in producing very stable dielectric ceramics and an indication of the SPS processing parameters suitable for this. The best sample showed at 1 MHz frequency the combination of relative permittivity 370, loss tangent 0.008, and DC resistivity 3 × 1012 Ωm.

Improved Photoluminescence Performance of Eu3+-Doped Y2(MoO4)3 Red-Emitting Phosphor via Orderly Arrangement of the Crystal Lattice.

In this study, we developed a technology for broadening the 465 nm and 535 nm excitation peaks of Eu3+:Y2(MoO4)3 via crystal lattice orderly arrangement. This was achieved by powder particle aggregation and diffusion at a high temperature to form a ceramic structure. The powdered Eu3+:Y2(MoO4)3 was synthesized using the combination of a sol-gel process and the high-temperature solid-state reaction method, and it then became ceramic via a sintering process. Compared with the Eu3+:Y2(MoO4)3 powder, the full width at half maximum (FWHM) of the excitation peak of the ceramic was broadened by two- to three-fold. In addition, the absorption efficiency of the ceramic was increased from 15% to 70%, while the internal quantum efficiency reduced slightly from 95% to 90%, and the external quantum efficiency was enhanced from 20% to 61%. More interestingly, the Eu3+:Y2(MoO4)3 ceramic material showed little thermal quenching below a temperature of 473 K, making it useful for high-lumen output operating at a high temperature.

Study on the Evolution Pattern of the Aromatics of Lignin during Hydrothermal Carbonization

Waste straw contains a large amount of lignin, and its resource utilization is not only in line with the national double carbon development strategy, but also to alleviate environmental pollution. Hydrothermal carbonization is a new thermochemical conversion technology, which has attracted much attention because it can directly transform carbon containing waste raw materials with high moisture content and low energy density. To investigate the physicochemical properties and aromatization changes of lignin hydrochar, hydrothermal carbonization experiments were carried out at 290 °C and a solid–liquid ratio of 1:20 for 0.00, 0.25, 0.50, 1.00, 1.50, 2.00, 4.00, 8.00 h, respectively. The experimental results shows that hydrothermal carbonization can increase the combustion quality of lignin. Physical and chemical properties analysis shows that with the increase of hydrothermal carbonization time from 0 to 2 h, the hydrochar content increased from 21.21% to 26.02% and the HHV of hydrochar increased from 20.01 MJ/Kg to 26.32 MJ/Kg. When the holding time exceeded 2 h, the carbon content and calorific value of hydrothermal tended to be stable. With the increase of holding time, FTIR analysis and XRD analysis show that the free hydroxyl groups in water-soluble lignin were easily combined with intramolecular and intermolecular hydrogen bonds, thus forming an ordered crystal arrangement. Subsequently, the crystal structure formed a well-arranged long chain through a strong hydrogen bond network, forming a ring structure in the process of aromatization. Aromatic ring structure accumulated, aromatization wave peak increased with holding time and aromatization intensified. Hydrochar crystal particles became larger and arranged in order. At the same time, the surface functional group detection and degree of crystallization were almost unchanged when holding time exceeded 2 h. The surface morphology of hydrochar was observed by SEM as follows: when the hydrothermal carbonization reaction of lignin entered the insulation stage, the microsphere structure began to aggregate and then became larger. When the holding time reached 2 h, the growth rate of carbon microspheres noticeably slowed. Therefore, the optimal hydrothermal carbonization time of lignin is 2 h, and hydrochar fuel has the best performance and aromatization.

One-dimensional stacking array of 10,20-diphenyl-5,15-diazaporphyrin metal complexes

We prepared a free-base 10,20-diphenyl-5,15-diazaporphyrin and its Ni(II), Cu(II), Pd(II), and Pt(II) complexes. These molecules uniformly form an infinite one-dimensional [Formula: see text]-stacking array in the solid state. The four-fold intermolecular hydrogen bonding interactions between the meso-nitrogen atom of the diazaporphyrin core and the ortho-hydrogen atom of the phenyl substituent dominate the crystal packing arrangement. The present study revealed that the meso-nitrogen atom of diazaporphyrins would be used as an inherent hydrogen bonding acceptor to construct supramolecular assemblies.

The Relationship between Microstructure and Mechanical Properties of PBST Two-Component Crystalline Random Copolymers with Different BT Contents

The mechanical properties of two-component crystalline random copolymers are primarily based on their microstructure. At the same time, the influence of the composition on the crystallization behavior and crystal structure of these materials is also well known. Thus, in this study, a poly (butylene succinate-co-butylene terephthalate) random copolymer (PBST) with different molar ratios of butylene terephthalate (BT) was prepared. A systematic analysis of the crystallization behavior, crystal structure, and mechanical properties of PBST with different BT contents was carried out using WAXD, SAXS, and DSC analyses. The investigations showed that PBST-37.5 containing 37.5 mol% of BT content had the lowest strength and highest elasticity among the different compositions. This was because the two-component crystallization of poly (butylene terephthalate) (PBT) and poly (butylene succinate) (PBS) was greatly inhibited at the corresponding BT composition and the crystal growth was the least perfect, imparting poor strength to the PBT-37.5. Alternately, when the content of BT was 32.5 mol% in the PBST, the PBS segment could crystallize, and both PBT and PBS crystals were formed in the PBST-32.5. Thus, PBST-32.5 showed a higher material hardness than PBST-37.5. In contrast, when the BT content was greater than 37.5 mol% in the PBST, only PBT crystals existed in the PBST copolymer. Further, as the BT content increased, the crystal size of PBT gradually increased, which led to a closer packing of the crystal arrangement, increasing the crystallinity. This led to a gradual increase in the strength of the PBST material and a gradual decrease in its elasticity.

Supramolecular assemblies in the molecular complexes of 4-cyanophenylboronic acid with different N-donor ligands.

Molecular complexes of 4-cyanophenylboronic acid (CB) with various N-donor compounds having different conformational features, for example, rigid (1,10-phenanthroline (110phen), 4,7-phenanthroline (47phen), 1,7-phenanthroline (17phen) and acridine (acr)) and linear (1,2-bis(4-pyridyl)ethane (bpyea), 1,2-bis(4-pyridyl)ethene (bpyee) and 4,4'-azopyridine (azopy)), have been reported. In all complexes, the -B(OH)2 moiety is found to be in a syn-anti confirmation, with the exception of structures containing 110phen, bpyee, and azopy, wherein, syn-syn conformation is observed. Further, CB molecules remain intact in all structures except in the complexes with some linear N-donor ligands, wherein -B(OH)2 transforms to monoester (-B(OH)(OCH3)) prior to the formation of corresponding molecular complexes. In such boronic monoester complexes, the conformation of -B(OH)(OCH3) is syn-anti with respect to the -OH and -OCH3 groups. Also, complexes mediated by azopy and bpyee exist in both hydrated and anhydrous forms. In these anhydrous structures, the recognition pattern is through homomeric (juxtaposed -CN and -B(OH)2) as well as heteromeric (between hetero N-atom and -B(OH)2) O-H⋯N hydrogen bonds, while only heteromeric O-H⋯N hydrogen bonds hold co-formers in all other structures. Depending upon the conformational features of both co-formers, molecules are packed in crystal lattices in the form of stacked layers, helical chains, and crossed ribbons. All structures are fully characterized by single-crystal X-ray diffraction and phase purity is established by powder X-ray diffraction. Additionally, correlation among structures is explained by calculating a similarity index and performing a Hirshfeld surface analysis to quantify the strength and effectiveness of different types of intermolecular bonds that stabilize these structures along with the presentation of energy frameworks, representing the strength of the interactions in the form gradient cylinders. Also, the morphology of each complex was computed by BFDH methodology to correlate with the actual crystal morphology and packing arrangement.

Combined Experimental and Theoretical Studies on the Rubbing-Induced Fluorescence Behavior of a Luminophore in the Solid State.

It is intricate to break and make chemical bonds in solid states compared to their solution states, so it is imperative to ascertain green proficient approaches by regulating the solid-state structures and their related material properties. Here, the rubbing-induced photoluminescence behavior of a luminophore (RIL) of the benzimidazole family in the solid state has been accomplished. Interestingly, upon gentle rubbing or mere scratching, solid-state fluorescence from the nonemissive pristine RIL was observed due to the aggregation-induced emission (AIE) phenomenon in the solid state, for which the phenolic moiety is present in the molecule and is accountable. The structure-property relationship of RIL and the mechanism responsible for this solid-state fluorescence characteristics have been explained with the help of experimental (using the single-crystal structure, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) images, etc.) and theoretical (by DFT and TDDFT) studies. The crystal arrangements with different stacking interactions and the SEM images after being rubbed revealed that the mechanical force- or pressure-induced slight deformation in the crystal arrangement notably facilitated the strong emission in the solid state. This rubbing-induced solid-state fluorescence in a new luminophore (RIL) through stacking of layers restricting the molecular motion has been developed here for the first time, and it can be explicitly employed in steganography techniques for data security. This present study will open up a new insight into the use of this RIL as a solid-state smart material for data security in coding devices in the future, and this developed approach may be helpful to ameliorate the design of new-generation smart materials by modifying the structure to attain other characteristics.

Vivaldi antenna for early cancer detection based on THz spectroscopy: Comparison between response of breast and skin cancer

this paper suggests a Vivaldi antenna for the THz frequency range with a wide bandwidth (more than 120% bandwidth) for early cancer detection with dimensions of 1λ× 0.5λ× 0.034λ for 0.5 THz with special novel arrangement of photonic crystal and taper grating reflector. The photonic crystal walls are implemented on both sides of the antenna to make an electric shield to concentrate energy for increasing the gain and directivity of the antenna and reducing the side lobe. Front to back (F/B) ratio is another problem for this THz antenna where the grating parasitic elements are used as the reflector to reduce the back lobe of the basic antenna. This antenna covers 0.5–2 THz with a maximum gain of 8.8 dB in the broadside. The proposed antenna is used for detecting breast and skin cancers which are modeled by Debye’s second-order model. The reflection and transmission, pulse response, and phase variation for normal and tumor tissue are considered for the reorganization of cancers. The results show that reflection and transmission, pulse responses are not effective factors for breast cancer detection in comparison to skin cancer while the phase response is the best solution for this type of cancer.

Influence of Mechanical Activation on the Formation of Yttrium Aluminum Garnet (YAG) at Lower Temperature

Yttrium aluminum garnet (YAG) is an important material which require high temperature of 1600°C in its solid-state reaction. To lower this temperature, mechanical activation process has applied to the system which make the crystal arrangement broken thus make it more reactive. This process results in homogeneous and fine particle distribution of Al2O3 and Y2O3 compared to manually mixed powders. Moreover, milling process also reduce the particle size of the Al2O3 and Y2O3 from 4694 nm and 349 nm down to 274 nm. This also lessen the crystallite size of Al2O3 and Y2O3 from 1010 and 164 Å to 310 and 50 Å respectively. Then, after calcination at 1100°C, the milled powders form YAG phase in the opposite of manually mixed powders which form YAM phase. YAG formed have nearly round shape with finer grain compared to manually mixed powders which still has large grain of Al2O3 and Y2O3. This formation temperature is much lower than the require conventional solid-state reaction.

Adaptable physics-based super-resolution for electron backscatter diffraction maps

In computer vision, single-image super-resolution (SISR) has been extensively explored using convolutional neural networks (CNNs) on optical images, but images outside this domain, such as those from scientific experiments, are not well investigated. Experimental data is often gathered using non-optical methods, which alters the metrics for image quality. One such example is electron backscatter diffraction (EBSD), a materials characterization technique that maps crystal arrangement in solid materials, which provides insight into processing, structure, and property relationships. We present a broadly adaptable approach for applying state-of-art SISR networks to generate super-resolved EBSD orientation maps. This approach includes quaternion-based orientation recognition, loss functions that consider rotational effects and crystallographic symmetry, and an inference pipeline to convert network output into established visualization formats for EBSD maps. The ability to generate physically accurate, high-resolution EBSD maps with super-resolution enables high-throughput characterization and broadens the capture capabilities for three-dimensional experimental EBSD datasets.

Highly soluble Ni(II) dithienylnorcorrole

Recently, norcorrole Ni(II) complexes have received much attention because they exhibit peculiar solid-state structures and fascinating electronic properties originating from their distinct antiaromatic character. In this work, we have prepared a norcorrole Ni(II) complex with 5-hexylthien-2-yl substituents at the meso-positions, of which the antiaromatic nature was evaluated by 1H NMR analysis as well as NICS and ACID calculations. The X-ray diffraction analysis elucidated its molecular structure and crystal packing arrangement. Crystal packing structures of Ni(II) meso-di(5-methylthien-2-yl)norcorrole and Ni(II) meso-di(5-hexylthien-2-yl)norcorrole were markedly different. The latter provided a polar crystal because of the unidirectional alignment of 5-hexylthien-2-yl groups in the solid state.

Design of quasi-phase-matching nonlinear crystals based on quantum computing

Quasi-phase-matching (QPM) makes it possible to design domain engineered nonlinear crystals for highly efficient and multitasking nonlinear frequency conversion. However, finding the optimal crystal domain arrangement in a meaningful time is very challenging sometimes impossible by classical computing. In this paper, we proposed a quantum annealing computing method and used D-Wave superconducting quantum computer to design aperiodically poled lithium niobate (APPLN) for coupled third harmonic generation (CTHG). We converted the optical transformation efficiency function to an Ising model which can be solved by D-Wave quantum computer. The crystal design results were simulated by using nonlinear envelope equation (NEE), which showed very similar conversion efficiencies to the crystals designed by using simulated annealing (SA) method, demonstrating that quantum annealing computing is a powerful method for QPM crystal design.

Design of InAs nanosheet arrays for high-performance polarization-sensitive infrared photodetection

Polarization-sensitive infrared photodetectors are widely needed to distinguish an object from its surrounding environment. Polarization-sensitive detection can be realized by using semiconductors with anisotropic geometry or anisotropic crystal arrangement, such as semiconductor nanowires and two-dimensional (2D) materials. However, these photodetectors show drawbacks in low light absorption, weak polarization sensitivity and stability issues. Here, we designed 2D InAs nanosheet based arrays that are highly suitable for polarization-sensitive infrared photodetection. By using the finite element method (FEM) based on COMSOL Multiphysics, we optimized the geometry of single free-standing InAs nanosheets, obtaining dichroic ratio up to 127 (average) in the wavelength range of 2–3 μm by reducing the thickness and increasing the height. Extending this to a nanosheet array with an optimized geometry, an enhancement of the absorption intensity from 45% (for a single nanosheet) to over 67% with a dichroic ratio exceeding 50 in the wavelength range of 2–3 μm can be achieved. Moreover, these unique light absorption properties are tolerant to incident angles up to 30°. The design of such nanosheet array provides a new route for the development of high-performance infrared photodetectors for polarization photodetection.

Debranched waxy maize resistant dextrin: Synthesis, ethanol fractionation, crystallization, and characterization

Waxy maize (Zea mays L.) dextrins (WMD), prepared by enzymatic debranching, were fractionated through precipitation in different concentrations of aqueous ethanol (50 %, 60 %, and 80 %). The fractionated WMDs were then crystallized at 4 °C or 50 °C for 2 days to prepare resistant dextrins (RD). Recovery yield, chain distribution, crystalline structure, thermal transition, and in vitro digestibility of the fractionated/crystallized WMDs were evaluated. Crystallization at 4 °C resulted in higher yields (>90 %) than that at 50 °C, regardless of the fractionation condition. The chain profile of the dextrins recovered at different temperatures appeared similar, but the longer chains had a greater tendency to associate. Crystal arrangement (A- or B-type) depended on the fractionation and crystallization conditions. Most crystals showed a typical B-type arrangement, except for the crystals prepared at 50 °C with 80 % ethanol (A-type). The enzyme resistance ranged from 49.9 % to 92.4 % depending on the fractionation and crystallization conditions.

Evolution of the Fracture Characteristics in a Rockburst under Different Stress Gradients

The variation in principal stress ratio and principal stress direction deflection caused by the stress gradient distribution of surrounding rock is one of the reasons leading to different types of strain rockbursts. Two typical rockburst failure modes of brittle gypsum debris are discussed based on the study of the macroscopic and microscopic appearance morphologies under different stress gradients. Based on the acoustic emission characteristic parameter analysis of the Gaussian mixture model (GMM), the evolution of internal crack propagation and the fracture mechanism during the rockburst under different stress gradients were explored. The results are as follows: (1) The generation and intensity of rockburst are related to the loading stress gradient. The larger the stress gradient, the more significant the dynamic phenomenon during the rockburst process. (2) There are obvious differences in the morphology and arrangement of crystals on the fracture surface of rockburst debris under different stress loading paths. The brittle fracture of debris can be divided into flake debris dominated by intergranular tensile fracture and massive debris dominated by transgranular shear fracture. (3) The AE characteristic parameter classification method based on the GMM has good applicability in crack classification. With an increase in the loading stress gradient, the proportion of the shear crack increases gradually, which is the main reason for the enhancement of the rockburst intensity.