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This study investigates NaY9Si6O26 ceramics prepared through the solid‐phase method, focusing on their microwave dielectric properties and crystallographic characteristics. X‐ray diffraction analysis reveals a hexagonal crystal structure for NaY9Si6O26 ceramics within the P63/m (176) space group. Rietveld refinement analysis precisely determines the lattice constants as a = b = 9.3423 Å, c = 6.7524 Å, and a unit cell volume of V = 510.3877 Å3. Additionally, Raman spectroscopy unveils a noteworthy correlation between the quality factor and the full width at half maximum of the A1g(O) mode at 878 cm−1. The structural attributes, including lattice fringes and diffraction patterns of hexagonal NaY9Si6O26 ceramics, are elucidated through transmission electron microscopy. Of significance are the microwave dielectric properties of NaY9Si6O26 ceramics sintered at 1465°C, revealing a relative permittivity (εr) of 10.42, an impressive Q × f product of 33 766 GHz (at f = 11.14 GHz), and a temperature coefficient of resonant frequency (τf) of −28.7 ppm/°C. This comprehensive investigation contributes to the understanding of both the structural and microwave dielectric characteristics of NaY9Si6O26 ceramics, with potential applications in advanced electronic devices. [ABSTRACT FROM AUTHOR]

This study delves into the microwave dielectric properties of Li2Y9(SiO4)6O2F ceramics, synthesized using the conventional solid-state method. By employing x-ray diffraction analysis and meticulous data refinement across various temperatures, we unequivocally confirm the hexagonal crystal structure of Li2Y9(SiO4)6O2F ceramics. The refined lattice parameters, observed at a sintering temperature of 1275°C, exhibit a = b = 9.33318 Å, c = 6.71725 Å, with a corresponding unit cell volume of V = 506.73529 Å3. In-depth scrutiny of the microstructure of the ceramics' grains using scanning electron microscopy (SEM) reveals an optimal relative density of 96.2%. Subsequently, the study explores the impact of porosity, packing fraction, relative density, and Si-O bond valence (VSi-O) on the microwave dielectric properties of Li2Y9(SiO4)6O2F ceramics. Notably, the Li2Y9(SiO4)6O2F ceramic sintered at 1275°C demonstrates superior performance metrics, boasting an εr value of 14.28, a Q × f product of 16,760 GHz (at f = 9.4 GHz), and a temperature coefficient of frequency (τf) at 3.14 ppm/°C. This comprehensive investigation contributes valuable insights into optimizing the microwave dielectric characteristics of Li2Y9(SiO4)6O2F ceramics for potential applications in advanced electronic devices. [ABSTRACT FROM AUTHOR]

This study presents the dielectric properties of Ba2Zr2Si3O12 ceramics, synthesized using the solid state method. The cubic crystal structure of Ba2Zr2Si3O12 ceramics was conclusively verified through the analysis of XRD patterns and subsequent structural refinement. Refined lattice parameters of a = b = c = 10.23178 Å were found, with a corresponding unit cell volume of V = 1071.159026 Å3. The grain microstructure of the ceramics was characterized using SEM, which showed density of 97.6% for the Ba2Zr2Si3O12 ceramic. The Si-O bond valences (VSi-O) were found to be closely related to the τf of the Ba2Zr2Si3O12 ceramics. The microwave dielectric properties of the Ba2Zr2Si3O12 ceramics sintered at 1490°C were ascertained to be εr = 15.08, Q × f = 14885 GHz (f = 9.9 GHz), and τf = −78.6 ppm/°C. [ABSTRACT FROM AUTHOR]

An ordering of the Sr cations over two crystallographic sites exists in F-modified aluminosilicate with composition of SrAlSiOF (SASF), opening opportunity to customize the local crystal accommodation environment for activators upon solid solution of Ba or Ca for Sr cations. A series of SrMAlSiOF:Ce (M = Ba, Ca) phosphors are synthesized by high temperature solid-state reaction method, and the dependence of luminescent properties and thermal stability on the solid solution contents of alkaline-earth metals are investigated in this work. The preferable substitution sites of Ba and Ca and the resultant influence on the local crystal structure of Ce and the performances of phosphors were discussed in detail. [ABSTRACT FROM AUTHOR]

A series of new chiral and achiral nickel(II) and palladium(II) complexes, {bis[ N, N′-(2,6-diethyl-4-naphthylphenyl)imino]-1,2-dimethylethane}dibromonickel 3a, {bis[ N, N′-(4-fluoro-2-methyl-6- sec-phenethylphenyl)imino]-1,2-dimethylethane}dibromonickel rac-( RS)- 3b, {bis[ N, N′-(4-fluoro-6- sec-phenethylphenyl)imino]-1,2-dimethylethane}dibromonickel rac-( RR/SS)- 3c and {bis[ N, N′-(4-fluoro-6- sec-phenethylphenyl)imino]-1,2-dimethylethane}dichloropalladium rac-( RR/SS)- 3d were successfully synthesized and characterized. The molecular structures of representative ligand rac-( RS)- 2b, nickel complex 3a, rac-( RR/SS)- 3c and palladium complex rac-( RR/SS)- 3d were determined by X-ray crystallography. The structures of complexes 3a and rac-( RR/SS)- 3c have pseudo-tetrahedral geometry about the nickel center, showing C2 molecular symmetry. However, the structure of palladium complex rac-( RR/SS)- 3d has pseudo-square planar geometry about the palladium center, showing C2 molecular symmetry. Complex 3e {bis[ N, N′-(2,6-dimethylphenyl)imino]-1,2-dimethylethane}dibromonickel was also synthesized for comparison. Nickel complex rac-( RS)- 3b bearing strong electron-withdrawing fluorine group in the para-aryl position and a chiral sec-phenethyl group in the ortho-aryl position of the ligand (one methyl group in the ortho-aryl position) displays the highest for ethylene and styrene , and produced highly branched polyethylene and syndiotactic-rich polystyrene. However, palladium complex rac-( RR/SS)- 3d shows low for ethylene and styrene due to the poor leaving group, Cl, attached to palladium and the unfavorable molecular structure. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive investigation into the dielectric properties of LiY 9 Si 6 O 26 ceramics, which were prepared for the first time using the solid-state method. XRD patterns and Rietveld refinement analysis conclusively demonstrate that LiY 9 Si 6 O 26 adopts a hexagonal crystal structure with space group P63/m (176). Furthermore, Raman spectroscopy reveals a significant correlation between the quality factor and the FWHM of the A 1g (O) mode at 879 cm−1. Transmission electron microscopy (TEM) was employed to verify the ordered layered structure inherent in the hexagonal LiY 9 Si 6 O 26 ceramics. The microstructure of the ceramic grains was analysed using scanning electron microscopy (SEM), which revealed a remarkably high relative density of 96.4% for the LiY 9 Si 6 O 26 ceramic. The Si–O bond valences (V Si – O) were found to be closely associated with the τ f in LiY 9 Si 6 O 26 ceramics. Remarkably, the microwave dielectric properties of LiY 9 Si 6 O 26 ceramics sintered at 1425 °C were ascertained to be ε r = 10.54, Q × f = 25,579 GHz (f = 10.3 GHz), and τ f = 2.64 ppm/°C. These outstanding properties position LiY 9 Si 6 O 26 ceramics as promising candidates for high-performance dielectric materials. [ABSTRACT FROM AUTHOR]

Efficiently selective co-crystallization strategy of sucrose-6-acetate (SA-6) from the complicated sucrose acylation mixture and facial co-former removal have been developed, which were driven by thermally stable co-crystals, proper solvent size and acid-base coupling. [Display omitted] • An efficiently selective co-crystallization separation of sucrose-6-acetate (SA-6) from the complicated sucrose acylation mixture can be realized by HAc, which can be facially removed by triethylamine. • The crystal structure of SA-6·HAc co-crystal has been determined, whose 3D hydrogen-bonding network is constructed from the SA-6 layers inserted by HAc with cavity size of 5.56 × 7.54 Å. • The optimizations on co-crystallization and co-former removal have been conducted, based on which the high SA-6 separation efficiency of 90.33 % in 1.5 h can be achieved. The purity of SA-6 can meet with the commercial requirement. • The mechanisms were proposed based crystal structure and theoretical calculations, in which thermally stable co-crystals, proper solvent size and acid-base coupling drive these processes. The searching for the facial and highly efficient separation method of sucrose-6-acetate (SA-6) in the acylation process seems significant for the production of sucralose. In this work, an efficiently selective co-crystallization strategy of SA-6 from the complicated sucrose acylation mixture has been developed, i. e. firstly, selective co-crystallization using acetic acid (HAc) as a cheap and green co-former (operation I), and co-former removal by triethylamine (TEA) (operation II). The crystal structure of SA-6·HAc co-crystal in the operation I has been determined, it is a 3D hydrogen-bonding network with HAc inserting among the SA-6 layers, whose cavity size is 5.56 × 7.54 Å. And the optimization on two operations have been conducted, including HAc dosage, solvent/aliphatic amine types and dosage, separation time/temperature. Based on the optimal conditions, the high SA-6 separation efficiency of 90.33 % in 1.5 h can be achieved, during which relative selectivity coefficient (α X) is lower than 0.003, deacidification ratio (δ) is higher than 99.47 %, and the product purity is 99.86 % (wt). Furthermore, the selective co-crystallization and co-former removal mechanisms were proposed base on crystal structure and theoretical calculations, in which thermally stable co-crystals, proper solvent size and acid-base coupling drive these processes. This strategy can enhance the separation efficiency of acylation process in sucralose production greatly. [ABSTRACT FROM AUTHOR]

A series of new chiral and achiral nickel (II) complexes, {bis[N,N′-(2-methyl-6-sec-phenethylphenyl)imino]-1,2-dimethylethane}dibromonickel rac-(RR/SS)-3a, {bis[N,N′-(4-isopropyl-2-sec-phenethylphenyl)imino]-1,2-dimethylethane}dibromonickel rac-(RSRS)-3b, {bis[N,N′-(2-methyl-4,6-di(sec-phenethyl)phenyl)imino]-1,2-dimethylethane}dibromonickel rac-(RSRS)-3c, and {bis[N,N′-(2,6-diisopropyl-4-(p-methylphenyl)phenyl)imino]-1,2-dimethylethane}dibromonickel 3d, were synthesized and characterized. The molecular structures of the representative ligand rac-(RSRS)-2c, complex rac-(RR/SS)-3a, complex rac-( RSRS)-3b, and complex 3d were determined by X-ray crystallography. Complex 3e {bis[N,N′-(2,6-dimethylphenyl)imino]-1,2-dimethylethane}dibromonickel was also synthesized for comparison. These complexes, activated by diethylaluminum chloride (DEAC) were tested in the polymerization of ethylene and styrene under mild conditions. Complex rac-(RSRS)-3c bearing one ortho-methyl group and two chiral bulky sec-phenethyl groups in the ortho- and para-aryl position of the ligand, activated by diethylaluminum chloride (DEAC) shows highly catalytic activity for the polymerization of ethylene [5.56 × 106 g PE/(mol Ni h bar)] and produced branched polyethylene (75 methyl, 9 ethyl, 5 propyl and 19 butyl or longer branches/1000 C at 40 °C). Interestingly, complex rac-(RSRS)-3c also displays highly catalytic activity (3.62 × 105 g polystyrene/(mol Ni h)) for styrene polymerization, and could produce syndiotactic-rich polystyrene (stereo-triad distributions: rr, 66.2%; mr, 18.8%; mm, 15.0%; stereo-diad distributions: r, 75.6%; m, 24.4% at 70 °C). The achiral catalyst 3d gave nearly atactic polystyrene (stereo-triad distributions: rr, 37.0%; mr, 32.7%; mm, 30.3%; stereo-diad distributions: r, 53.4%; m, 46.6% at 70 °C). [ABSTRACT FROM AUTHOR]

• IRFD saved 18.2–22.7% drying time of instant quinoa required for FD. • IRFD process better maintained the flavor of instant quinoa. • Pressure cooked instant quinoa had the highest porosity and best rehydration behavior. • Pressure cooking caused the softer and thicker texture of rehydrated instant quinoa. The effects of cooking methods (pressure cooking, microwave cooking, and atmospheric pressure cooking) and infrared-assisted freeze drying (IRFD) on drying characteristic, crystalline structure, pasting property, rehydration behavior, microstructure, texture, and flavor of instant quinoa samples were investigated. Results showed that IRFD significantly reduced the drying time needed for freeze drying (FD). The crystalline structure of starch in raw quinoa was destroyed in cooking process, IRFD process well maintained the gelatinized state of quinoa samples. The pressure cooked samples owned the highest porosity and best rehydration ability. Pressure cooking and microwave cooking caused the softer and thicker texture of rehydrated instant quinoa samples. As for the flavor of quinoa sample, IRFD possessed the stronger retention ability compared with FD. In summary, pressure cooking and IRFD could be the applicable processing methods for the production of instant quinoa product or other dehydrated instant product with high quality. [ABSTRACT FROM AUTHOR]

In this work, veritable carbothermal synthesis of SrAlSi 4 N 7 :Eu2+ red-emitting phosphors using entire oxides raw materials and the elimination of residual carbon survived in materials via non-thermal plasma oxidation route are demonstrated. The crystal structure and photoluminescent properties of carbothermal-synthesized SrAlSi 4 N 7 :Eu2+ phosphors and the residual carbon elimination effect of non-thermal plasma oxidation are investigated in detail. Experiment results show that the residual carbon survived in carbothermal-synthesized SrAlSi 4 N 7 :Eu2+ phosphors could be eliminated effectively by non-thermal plasma oxidation, leading to the significant enhancement of luminescent properties. The presented work affords an economic carbothermal reduction method to synthesize nitride phosphors using low cost entire oxides raw materials and recommends a promising approach to eliminate the residual carbon in carbothermal-synthesized materials. • SrAlSi 4 N 7 :Eu2+ phosphor was synthesized by carbothermal method using entire oxides raw materials. • Elimination of residual carbon was demonstrated by non-thermal plasma oxidation technology. • Luminescent property was enhanced owing to the removal of residual carbon after plasma treatment. • The elimination of residual carbon by oxygen-plasma was higher than that by air-plasma. [ABSTRACT FROM AUTHOR]

In this work, the luminescence efficiency and thermal stability of NaZr 2 (PO 4) 3 :Eu2+ phosphors were significantly improved through Na+-Sc3+ ions substitution for Zr4+ ions. The evolutions of crystal structure and luminescent performances induced by Na+-Sc3+ ions substitution were investigated in details for Na 1+x Zr 2-x Sc x (PO 4) 3 :Eu2+ phosphors. The extra Na+ ions occupied the interstitial sites in NaZr 2 (PO 4) 3 lattice accompanied with the replacement of Zr4+ ions by Sc3+ ions, resulting in the increase of crystal structure density of materials. As a result, the displacement (ΔR) between the ground state and excited state of Eu2+ activators in the configuration coordinate diagram was decreased because of the increased crystal structure density induced by Na+-Sc3+ ions substitution, then leading to the significant improvement of luminescence efficiency and thermal stability. The presented study revealed that crystal structure density might be used a useful proxy in screening higher performance phosphors. • Enhanced luminescence efficiency and thermal stability for NaZr 2 (PO 4) 3 :Eu2+ phosphor was demonstrated. • The Na+-Sc3+ substitution results in the increase of crystal structure density. • Increase of crystal structure density leads a smaller displacement (ΔR) for activators. • Increased crystal structure density was responsible for the enhancement of luminescent performances. [ABSTRACT FROM AUTHOR]