Crystal Unit Research Articles

Characterization of physically stable oleogels transporting active substances rich in resveratrol

Oleogels, substances that have a liquid phase of continuous oil, are being explored as a potential substitute for trans fatty acids and saturated fatty acids in food. To develop more stable and nutritious alternative lipids using blueberry extract, oleogels loaded with resveratrol (R) and blueberry extract were prepared using soybean oil (SO) and peanut oil (PO) as base oils, and β-sitosterol and lecithin as low-molecular-weight complex oleogelators. Microstructural characterization of oleogels showed that R-loaded and R-enriched blueberry extracts maintained the degree of cross-linking between oleogel crystal units to a certain extent as well as maintained or improved the mouthfeel and hardness of the oleogels. Differential scanning calorimetry and rheometric results demonstrated that the R-loaded ternary oleogels had good thermal stability and strength. With prolonged storage, the physical stability of peanut oil oleogels (POO) was better than that of soybean oil oleogels (SOO). In addition, in vitro simulation experiments revealed that the oleogels could better serve as a carrier for R but could inhibit their bioavailability in R-loaded oleogels.

Anomalous LO-TO splitting observed by combined IR reflectance and Raman scattering in KTiOPO4 (KTP) single crystal

A comprehensive study of vibrational spectra of a KTP single crystal is presented using both Raman scattering and Infrared (IR) reflectance. The 196 mode frequencies are listed according to a revised group theoretical analysis, which addresses the different atomic clusters comprising the crystal unit cell and their symmetry. Inverse LO-TO splitting is suggested to interpret the ν3 vibrational spectra of the PO43- clusters of the A1 symmetry. Theoretical account invokes a proximity between strong and weak polar vibrations and Lyddane-Sachs-Teller’s model of LO-TO splitting in a dielectric medium [1]. Many other mode frequencies appear too close to allow unequivocal interpretation of their LO-TO splitting sign.

Base pairs with 4-amino-3-nitrobenzonitrile: comparison with the natural WC pairs. Dimer and tetramer forms, Infrared and Raman spectra, and several proposed antiviral modified nucleosides

Base pairs of 4-amino-3-nitrobenzonitrile (4A-3NBN) molecule with uracil, thymine and cytosine nucleobases were optimized and compared to natural Watson-Crick (WC) pairs. The slightly greater flexibility of the -NO2 group of 4A-3NBN than the N3-H group of the natural nucleobases together with a noticeable higher dipole moment of its pairs can facilitate disruption of the DNA/RNA helix formation. Several new mutagenic modified nucleosides with 4A-3NBN and 3-amino-2-nitrobenzonitrile (3A-2NBN) were proposed as antiviral prodrugs and their base pairs optimized. The special characteristics of these prodrugs appear appropriated for their clinical use. The counterpoise (CP) corrected interaction energies of the base pairs were calculated and compared to the natural ones. The M06-2X DFT method was used for this purpose. The molecular structure of 4A-3NBN was analyzed in detail and the crystal unit cell was simulated by a tetramer form and eight dimer forms. The performance of the B3LYP, X3LYP and M06-2X methods was tested on the vibrational wavenumbers in the monomer, dimer and tetramer forms of 4A-3NBN. The observed IR and Raman bands were assigned according to the optimum dimer II form determined by B3LYP and by the tetramer form calculated by M06-2X, which is the expected unit cell that forms the crystal net. The two best scaling procedures were used. Communicated by Ramaswamy H. Sarma

Spin splitting in low-symmetry quantum wells beyond Rashba and Dresselhaus terms

Spin-orbit interaction in semiconductor structures with broken space inversion symmetry leads to spin splitting of electron and hole states even in the absence of magnetic field. We discover that, beyond the Rashba and Dresselhaus contributions, there is an additional type of the zero-field spin splitting which is caused by the interplay of the cubic shape of crystal unit cell and macroscopic structure asymmetry. In quantum wells grown along low-symmetry crystallographic axes, this type of spin-orbit interaction couples the out-of-plane component of carrier's spin with the in-plane momentum whereas the coupling strength is controlled by structure inversion asymmetry. We carry out numerical calculations and develop an analytical theory, which demonstrate that this interaction dominates $\mathbit{k}$-linear spin splitting of heavy-hole subbands in a wide range of parameters.

A facile strategy for high performance air-processed perovskite solar cells with dopant-free poly(3-hexylthiophene) hole transporter

Poly(3-hexylthiophene) (P3HT) based devices possess potential toward low-cost and easy fabrication for high-performance perovskite solar cells (PSCs). However, these devices currently suffer from stability and relative low performance. Herein, a gradient mixed-cation perovskite is obtained by a facile strategy of tailoring MAPbI3-xClx, in which MAFAPbI3-xClx were constructed in ambient air by directly spin-coating FAI onto perovskite intermediate phase. The pristine device shows an inferior power conversion efficiency (PCE) of 13.71%, whereas the as-optimized device achieves a PCE of 16.26%. A gradient distribution of FA cation is revealed by crystal unit parameters and energy dispersive spectrometer (EDS). The lifted valence band edge matches better with the HOMO of P3HT, thus resulting in the faster charge extraction. In addition, the reduced trap states lead to the enhanced crystallinity and the mitigation of perovskite/P3HT interface, and then the stability is significantly enhanced. Our work provides a facile way to improve the performance of P3HT based air-processed PSCs, which can bring these devices closer to low-cost commercial applications.

Strain-induced changes of the X-ray diffraction patterns of cross-linked Poly(dimethylsiloxane): The texture hypothesis

Poly(dimethylsiloxane) is a widely used silicone polymer that undergoes partial crystallization both as free oil and rubber when sufficiently cooled. However, a description of its crystalline structure surprisingly remains a totally open question. In particular X-ray diffraction fiber patterns of stretched silicone rubbers display impressive changes with strain and a recently proposed explanation involves a rich polymorphism. The present study develops the different idea that the X-ray pattern evolution merely reflects changes in the crystalline texture: a single crystalline phase is present with a structure virtually unaffected by strain while the axis of preferential orientation for the crystallites progressively changes. This enables a quantitative description of the X-ray fiber patterns, but the remaining fundamental structural issues are underlined. • The structure of the crystalline phase of polydimethylsiloxane remains an open question. • A simple explanation for the evolution of low-temperature x-ray patterns is proposed. • It includes a single crystalline phase and changes in crystalline texture. • A fundamental issue is the orientation of polymer chains in the crystal unit cell.

Solubility improvement of gallic acid in water through cocrystal formation with the solvent-drop grinding method and tartaric acid as co-former

Background: Quality, safety, and efficacy are required in pharmaceutical preparations on the market. The role of tested active substances and additives in producing a product formula that is stable, consistent, and meets standards. Solubility is an important parameter for achieving systemic drug concentration and pharmacological response. Cocrystals, for example, have been studied extensively to increase their solubility. Solvent-drop grinding is used to combine active pharmaceutical substances with co-formers into a single crystal unit. Gallic acid is an antioxidant, antimicrobial, anti-inflammatory, anticancer, cardioprotective, gastroprotective, and neuroprotective chemical compound. It is soluble in water thus used to make cocrystals. Also, tartaric acid is crystallised, inert, and easily soluble in water, so it is a natural choice as a co-former. Objectives: Solvent-drop grinding was used to characterise the gallic acid cocrystal formation with tartaric acid co-former, and the effect of gallic acid cocrystal formation with tartaric acid as a co-former was tested using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Method: The ratios of gallic acid cocrystals to tartaric acid co-formers were 1:0, 1:1, and 2:1. After crushing gallic and tartaric acids for four minutes, a few drops of ethanol solvent were added until the mixture was homogeneous. Result: There was an increase in the cocrystal solubility test. The presence of hydrogen bonds between the co-formers of gallic and tartaric acids is indicated by a wavenumber shift in the cocrystal's infrared spectrum. Furthermore, each cocrystal creates a new peak in the X-ray pattern, indicating that hydrogen bonds formed cocrystals. Conclusion: The co-crystallisation method can increase the solubility of gallic acid in water by 1.21 times.

Critical field analysis and magnetic properties of perovskite manganese oxide La0.8Ca0.2Mn1-xNixO3(x = 0.0,0.1,0.2)

Critical field analysis and the magnetocaloric effect of the polycrystalline perovskite manganese oxide samples, La0.8Ca0.2Mn1-xNixO3 (x = 0.0,0.1,0.2), which were prepared using a traditional solid phase reaction method, were explored. The data obtained from X-ray diffraction (XRD) measurements of the polycrystalline samples show good single-phase properties. The replacement of a given Mn3+ ion fraction by Ni2+ions decreased the crystal parameters and unit cell volume, Curie temperature (Tc), and the magnetic and the magnetic entropy change. These property changes originate from the partial substitution of Mn3+ ions by Ni2+, which changes the Mn3+/Mn4+ ratio and consequently weakens the double exchange (DE) effect. At an applied magnetic field of 7 T, the maximum difference in magnetic entropy of the undoped sample is 6.15 J/kg•K, and the refrigeration efficiency is 422.94 J/kg. The critical parameters of the parent material and the doped sample fit well to the Tricritical model. The La0.8Ca0.2Mn1-xNixO3 samples with x = 0.0 exhibit crossover of the phase transitions, which can be first or second order. The observed phase transitions of samples with x = 0.1 and 0.2 are exclusively second order. Around the TC of La0.8Ca0.2Mn1-xNixO3 (x = 0.0, 0.1 and 0.2) compounds, the correlation of the magnetic field with the maximum change in magnetic entropy follows a power law.

Photonic metacrystal: design methodology and experimental characterization

We report a design methodology for creating high-performance photonic crystals with arbitrary geometric shapes. This design approach enables the inclusion of subwavelength shapes into the photonic crystal unit cell, synergistically combining metamaterials concepts with on-chip guided-wave photonics. Accordingly, we use the term "photonic metacrystal" to describe this class of photonic structures. Photonic metacrystals exploiting three different design freedoms are demonstrated experimentally. With these additional degrees of freedom in the design space, photonic metacrystals enable added control of light-matter interactions and hold the promise of significantly increasing temporal confinement in all-dielectric metamaterials.

Liquid Crystal-Based Organosilicone Elastomers with Supreme Mechanical Adaptability.

Elastomers with supreme mechanical adaptability where the increasing stress under continuous deformation is significantly inhibited within a large deformation zone, are highly desired in many areas, such as artificial muscles, flexible and wearable electronics, and soft artificial-intelligence robots. Such system comprises the advantages of recoverable elasticity and internal compensation to external mechanical work. To obtain elastomer with supreme mechanical adaptability, a novel liquid crystal-based organosilicon elastomer (LCMQ) is developed in this work, which takes the advantages of reversible strain-induced phase transition of liquid crystal units in polymer matrix and the recoverable nano-sized fillers. The former is responsible for the inhibition of stress increasing during deformation, where the external work is mostly compensated by internal phase transition, and the latter provides tunable and sufficient high tensile strength. Such LCMQs were synthesized with 4-methoxyphenyl 4-(but-3-en-1-yloxy)benzoate (MBB) grafted thiol silicone oil (crosslinker-g-MBB) as crosslinking agent, vinyl terminated polydimethylsiloxane as base adhesive, and fumed silica as reinforcing filler by two-step thiol-ene “click” reaction. The obtained tensile strength and the elongation at break are better than previously reported values. Moreover, the resulting liquid crystal elastomers exhibit different mechanical behavior from conventional silicone rubbers. When the liquid crystal content increases from 1% (w/w) to 4% (w/w), the stress plateau for mechanical adaptability becomes clearer. Moreover, the liquid crystal elastomer has no obvious deformation from 25 °C to 120 °C and is expected to be used in industrial applications. It also provides a new template for the modification of organosilicon elastomers.

Some aspects of improving the quality of GTE cast turbine blades of nickel superalloys

The results of the development of casting technology for single-crystal high-pressure turbine blades from nickel superalloys with a crystallographic orientation (CGO) [001] were obtained on an automated casting unit for directional crystallization UVNK-9A, at machine-building enterprise. The construction of the casting blades blocks, technologies for the manufacture of molds, rods and casting of GTE working blades of heatresistant nickel alloys with a single-crystal structure and set-up CGO have been developed under real production conditions on UVNK-9A units substituting through-type furnaces. It is shown that preproduction series of single-crystal castings of working blades with shroud shelf were obtained, with a yield of suitable structure ≥ 75%. The structural-phase characteristics of the alloy of single-crystal blades castings were investigated by scanning electron microscopy in as cast state and after subsequent heat treatment. A comparative quantitative analysis of the microstructure and strength characteristics of supernickel alloy castings with CGO [001], obtained on a high-gradient directional crystallization unit and in a through-type furnace.

Dual-band all-dielectric chiral photonic crystal

We present an all-dielectric chiral photonic crystal that guides the propagation of electromagnetic waves without backscattering for dual bands. The chiral photonic crystal unit cell is composed of four dielectric cylinders with increasing inner diameter clockwise or anticlockwise, which leads to chirality. It is demonstrated that the proposed chiral photonic crystal can generate dual band gaps in the gigahertz frequency range and has two types of edge states, which is similar to topologically protected edge states. Hence, the interface formed by the proposed 2D chiral photonic crystal can guide the propagation of electromagnetic waves without backscattering, and this complete propagation is immune to defects (position disorder or frequency disorder). To illustrate the applicability of the findings in communication systems, we report a duplexer and a power divider based on the presented all-dielectric chiral photonic crystal.

Synthesis and magnetic characterizations of [formula omitted] solid solution with [formula omitted] 0.016 as a new low – dimensional dilute magnetic - semiconductor material

In this study, TlInS2 layered semiconducting compound in which In3+ ions were partially substituted by ∼ 1.6 %Fe3+ transition metal ions was prepared by means the Bridgman – Stockbarger technique. The crystal structure of TlIn1-xFexS2 with x= 0.016 in combination with magnetization dynamics and magnetic resonance measurements have been studied. Energy dispersive X-ray (EDX) spectrum of Fe – substituted TlInS2 compound confirms the presence of all the constituent elements in stoichiometric proportions. We concluded that the magnetic properties of TlIn1-xFexS2 were induced by substituting trivalent iron atoms in the place of In3+ ion sites located at the center of In3+S42- structural units of TlInS2 crystal. EPR study reveals that the local site symmetry around Fe3+ center is orthorhombic. The orthorhombic local symmetry can be considered to originate crystal field arising from Tl ligands in the trigonal cavities surrounding Fe3+ transition metal ion. The angular dependence resonance lines show that the crystal lattice contain two structurally equivalent Fe3+ centers localized at different tetrahedron arrays of crystal structure. The temperature dependences of the magnetization measured in the zero - field cooling (ZFC) and field cooling (FC) regimes in the magnetic field of ∼ 50 Oe is found to correspond to a paramagnetic behavior at low temperatures. It has been founded that Fe moments in the TlInS2 host lattice can be ordered to ferromagnetic – like structure. This conclusion in magnetic behavior of TlIn1-xFexS2 compound is well - justified by the existence of very narrow hysteresis loops in the field dependent magnetization curves. Thus, in this work we propose that Fe – diluted TlInS2 is a new and promising dilute magnetic semiconductor with a large potential for future spintronic applications.

Precisely control the ultraviolet to blue light conversion for plant growth: Rigid crystal structure, lattice substitution and flux effect in the Ca1.1Sr0.9SiO4:Ce3+, Li+ phosphor

A series of Ce3+-doped Ca1.1Sr0.9SiO4-based phosphors has led to the development of a fingerprint spectrum to precisely tune the UV to blue light conversion for application in the photosynthesis of different plants in agriculture. The addition of MX2 flux (M = Ca, Ba; X = Cl, Br) not only remarkably enhances the luminescence efficiency, but also fine tunes the photoluminescence (PL) wavelength and photoluminescent excitation (PLE) peaks. With increasing Al content doping in the Si site, the excitation and emission peaks of the Ca1.08Sr0.88Si1-zAlzO4:0.02Ce3+,0.02Li+,0.04CaCl2 (CSSA:CeLiCaCl) phosphor shift to longer wavelengths, i.e. from 367 (z = 0) to 373 (z = 0.04) nm and from 429 (z = 0) to 448 (z = 0.04) nm, respectively, along with an increase of the luminescence intensity. Rietveld refinement of the XRD data for Ca2-ySrySiO4 (y = 0.8, 0.9, 1.0) revealed that Ca1.1Sr0.9SiO4 has the highest rigidity, which can be correlated with the shortest Si-O bond length and strongest bond energy along the series. The crystal structure and unit cell parameters of CSSA:CeLiCaCl (z = 0, 0.03 and 0.05) were also obtained, revealing that the efficient and tunable blue emission of the CSSA:CeLiCaCl phosphors can be attributed to the crystal structure distortions induced by the [(Si/ Al)O4] tetrahedron, while high rigidity is maintained. The combined effects of the Si4+ substitution by Al3+ and flux addition on the crystal structure and luminescence properties of the Ce3+-doped Ca1.1Sr0.9SiO4 phosphors are discussed in detail.

Design of a dual electrochemical quartz crystal microbalance with dissipation monitoring

Abstract. The design and fabrication of a dual electrochemical quartz crystal microbalance sensor unit with dissipation monitoring (EQCMD) for in situ monitoring of crystallization processes, such as the formation of zeolites from liquid media, is reported. The integrated temperature unit is based on Peltier elements and precision temperature sensors with accurate and fast temperature control. In this design, two thickness-shear mode quartz disk resonators are oppositely arranged, enabling the application of an electric field through the sample while concurrently being able to monitor the resonance frequencies and quality factors of both resonators. As demonstrated experimentally, this allows for the characterization of the sample by means of the viscosity, via the acoustic impedance, and the electrical conductivity. Monitoring zeolite formation based on these parameters, however, turned out to be challenging, mainly because the electrodes suffered from severe corrosion. Despite the use of chemically resistant materials and insulating coatings, the electrodes were attacked by the reaction medium, presumably due to surface defects. Furthermore, air bubbles, which developed over time and adhered persistently to the quartz surfaces, also had a negative influence on the measurement. Despite the encountered issues, we want to communicate our sensor design, as its basic functionality, including the dedicated electronics and software perform well, and reporting the observed issues will enable further progress in this field.

Synthesis and diffraction, computational exposure, hardness and interaction studies of EN2MNYM3NA crystalline material for mechanized, electronic and bio utilities

(E)-N-[(2-methoxynaphthalen-1-yl) methylidene]-3-nitroaniline - EN2MNYM3NA crystal is grown by slow evaporation solution growth method. The studies such as single crystal XRD, PXRD, unit cell, 3Dimensional pattern, Fourier impact and Laplace level interactive as well as Hirshfeld interactions data with the finger print profile, the weak force blow and profile are completed. The lattice constants with a, b, c values as 12.8482 Å, 15.4087 Å, 7.6234 Å and beta as 98.04O and volume as 1509.23 Å3 with material’s chemical formula as C18H14N2O3 The weak interactions of 50% and 75% are well enunciated with value of n as 2.93 for hardness coefficient; the anti-diabetic value for macro scaled EN2MNYM3NA as 39.92 (IC50) and the resolution and the elevated Isovalue value is 0.5; Globularity value as 0.721; Asphericity as 0.198; The scalings for the versatile energy and electron densities are well measured and reported properly.

Design of continuously deformable topological phononic structures and their application to elastic waveguides

We design a topological phononic crystal in a thin plate, aiming at the development of an efficient elastic waveguide based on the concept of band topology in phonon dispersion. We adopt a snowflake-like structure for the crystal unit cell and search for the optimal structure that exhibits the topological phase transition of the three-dimensional phononic crystal by changing the unit cell structure. The bandgap width can be adjusted by varying the length of the branch of the snow side, and a topological phase transition occurs at the unit cell structure with three-fold rotational symmetry. Elastic waveguides based on edge modes appearing at interfaces between crystals with different band topologies are designed, and their transmission efficiency is evaluated numerically and experimentally. The results demonstrate robustness of the elastic wave propagation in thin plates. Moreover, we experimentally estimate a robustness of the topologically protected propagating states against structural inhomogeneities. The results obtained in this study pave the way for practical development of new surface acoustic wave technologies for high-frequency communication devices.

MicroscopicEvaluation of Leaf of Balanites Aegyptiaca (L.)Delile: A Review Article

Introduction:Leaves of Balanites aegyptiaca(L.) Delileare commonly used for diabetes. Literature survey revealed that notmuch work has been done on this plant, especially on leaves. So detailed microscopical study was done for its identification. Methods: Transversesection and powder microscopy wascarriedoutonleavesofBalanitesaegyptiaca(L.)Delile.Result: Microscopical study showed dorsiventaral midrib and smooth, even and thick lamina. Thelamina was isolateraland 350 μm thick. The marginal part of the laminawas bluntly conical measuring 200 μm thick. Calcium oxalate crystals wereabundant in the mesophyll tissue. The crystals were druses and rosettetypes.Theveinsformedwell definedvein-islets ofpolygonal outline. The vein terminations were well developed and thick, short and straight. At the end of the veinterminationoccurredaclusterofsquarish,thickwalledwidesclereids.Theleafwasamphistomatic, However, the stomata on the abaxial side were more in frequency than on theadaxial side. The abaxial epidermal cells were small, polygonal and fairly thick walled. Theanticlinal walls were straight. The trichomes were unicellular, unbranched and thick walled.Crystal bodies were wide spread in the powder. The crystals were exclusively druses, which werespherical bodies comprising manypointed triangular small crystal units. Analysis and Discussion:The present researchprovided useful information in regard to its correct identity, evaluation and helped to differentiate from thecloselyrelated otherspecies ofBalanites aegyptiaca(L.)Delile. Hence, it furnished the data for future standardization of the drug.

Structural, vibrational, thermal, and optical properties of L-threonine crystals containing Ce3+ ions

In this study, L-threonine (L-Thr) crystal containing Ce3+ (L-ThrCe) impurity was grown through the slow solvent evaporation method. The structural data obtained by X-ray diffraction and Rietveld's refinement revealed that the L-ThrCe crystal crystallizes in the orthorhombic structure with P212121-space group and that the Ce3+ ions probably occupy interstitial spaces within the crystal, promoting a slight expansion on the crystal unit cell volume and a slight strain increase. Fourier-transform infrared and Raman spectroscopy showed that the Ce3+ ion slightly affects the crystalline lattice. Thermal analyses indicated that the L-ThrCe crystal has stability from 300 K up to 483 K. In addition, the L-ThrCe sample showed three bands into the UV-Vis region (240, 253, and 299 nm) characteristic of Ce3+ ions due to the 4f-5d transition. From photoluminescence, it was possible to observe emission broadband with a maximum around 350 nm when excited at 255 nm, corresponding to 2D → 2F7/2, 2F5/2 transitions of the Ce3+ ion. The present study demonstrated that the L-ThrCe crystal has light emission in the ultraviolet region, and it expands the range of potential materials for optical applications.

Balanced change in crystal unit cell volume and strain leads to stable halide perovskite with high guanidinium content.

Up-to-date studies propose that strain in halide perovskites is one of the key factors that determine a device's efficiency and stability. Here, we show a systematic approach to characterize the phenomenon in the standard methylammonium lead iodine (MAPbI3) perovskite system by: (i) the substitution of some MA by guanidinium (Gu); (ii) the incorporation of PbS quantum dot (QD) additives and (iii) addition of both Gu and PbS at the same time. We studied the effect of these incorporations on the film strain and crystal cell unit volume, and on the solar cell device efficiency and stability. Gu cations and PbS QDs affect the strain, the former due to the relatively large dimensions of Gu, and the latter due to the lattice matching parameters. With the control of Gu and PbS QD content, higher performance and longer solar cell stability are obtained. We demonstrated that the presence of Gu and PbS QDs alters the structure of perovskite, in terms of modification of the unit cell volume and strain. The greater size of Gu cations produces a MAPbI3 unit cell volume expansion as Gu is incorporated, modifying the strain from compressive to tensile. PbS QDs aid Gu incorporation, producing a unit cell volume expansion. In the case of 15% mol Gu incorporation, the addition of PbS QDs modifies strain from compressive to tensile, limiting the deleterious effect. At the same time the unit cell volume is less affected, increasing the solar cell stability. Our work shows that the control of compressive strain and the unit cell volume expansion lead to a 50% increase in T 80, the time in which the PCE decreases to 80% of its original value, increasing the T 80 value from 120 to 187 days under air conditions. Moreover it highlights the importance of exploiting not only the control of the strain induced by internal component, the cation, but also the strain induced by the external component, the QD, associated instead with critical volume variation of metastable perovskite unit cell volume.