Highly Stable Red‐Emitting Sr2Si5N8:Eu2+ Phosphor with a Hydrophobic Surface

One of the biggest problems in white light‐emitting diodes (WLEDs) is the moisture‐induced degradation of phosphors. This paper proposes a simple and feasible surface modification method to solve it, whereby a hydrophobic surface layer is developed on the surface of the phosphors. The particular case of orange‐red‐emitting Sr₂Si₅N₈:Eu²⁺ (SSN) phosphor was investigated. The mechanism to develop the hydrophobic layer involves hydrolysis and polymerization of tetraethylorthosilicate (TEOS) and polydimethylsiloxane (PDMS). The experimental results showed that the surface layer of SSN phosphor was successfully modified to a hydrophobic nanolayer (8 nm) of amorphous silicon dioxide that contains CH₃ groups in the surface. This hydrophobic surface layer gives the modified phosphor superior stability in high‐pressure water steam conditions at 150°C.     

Glass-ceramics in the CaO–MgO–Al2O3–SiO2 system as potential dental restorative materials

This paper reports on development of novel alumina-containing glass-ceramics (GCs) with a high content of Al₂O₃ (12.5 wt.%) in the CaO–MgO–Al₂O₃–SiO₂ system aimed for dental restorations. The thermal properties of the parent glasses, the microstructure and the mechanical properties of the produced sintered and crystallized GCs along with bio-inertia performance were experimentally studied. Dense, white, and bio-inert GCs, comprised of melilite, either as a single-phase or with diopside, were produced. The values of flexural strength ranged between 120 and 171 MPa, the modulus of elasticity varied between 28 and 42 GPa, while the values of the hardness and the fracture toughness (measured by the indentation–Niihara equation) ranged from 6.3 to 7.0 GPa, and from 2.6 to 2.8 MPa m^0.5, respectively. The mechanical properties of the produced GCs, after being meticulously compared with the mechanical properties of GCs of various compositions reported in literature, including commercial ones, are a good match to the properties of dental hard tissues, and satisfy the requirements of the ISO 6872 “Dentistry-Ceramic Materials”.     

Whole body scanning as a tool for clothing sizing: effects on women’s body satisfaction

Abstract

Whole-body scanning is increasingly used in the clothing industry, including in large-scale sizing surveys and virtual fitting. However, the impacts of 3D scanning on women’s body satisfaction are unclear as no previous studies have investigated impacts in a controlled experiment. This experiment investigated any causal effect of 3D whole-body scanning, as used in clothing applications, on women’s body satisfaction. Seventy women aged 18–35?years completed body image measures at baseline, immediately post-test, and two weeks later. At post-test relative to controls and controlling for baseline scores, women randomly allocated to the scanner condition scored significantly higher on Body Areas Satisfaction and significantly lower on Self-classified Weight, and positive effects persisted two weeks beyond the experimental session. Results suggest that whole-body scanning may improve women’s body satisfaction and reduce perceived overweight relative to controls, though further research is necessary to examine the reliability of this effect and underlying mechanisms.     

Influence of synthesis process on the dielectric properties of B-doped SiC powders

Fine powders (～0.7 μm) of SiC doped with 3 mol% and 10 mol% B were successfully produced by mechanical activation assisted self-propagating high-temperature synthesis (MASHS). The experimental results showed that the presence of B caused a reduction in the combustion temperature, shrinkage of the crystal lattice, an increase in the tendency of the grains to be crystallized, and a decrease in the dielectric properties in the frequency range between 8.2 and 12.4 GHz, specifically the real (?′) and the imaginary parts (?″) of complex permittivity and the loss tangent (tan δ). Analysis of the results suggests that B ions should be preferably accommodated in the Si sites of the SiC lattice and cause a reduction in the number of defects (V_Si, V_C, and C_Si), which results in a decrease in the dielectric properties. Comparison of the experimental results of this study with results reported in similar earlier studies reveals that the influence of B on the dielectric properties of the B-SiC powders depends strongly on the synthesis process.     

Line and point cluster models for spatial health data

Spatial cluster modelling of small area disease incidence and mortality has previously focused on clusters where excess risk is distributed around fixed points, and the aim is the reconstruction of these points (cluster centers). Often there is a need to assess clusters of a different form, such as around roads or river systems. These clusters are often linear or can be approximated by combinations of several linear segments. In this paper the recovery of point and line clusters is considered jointly. An example application is given where both linear or point clustering could be present.     

ESI‐MS Study of Some C10 Iridoid Glycosides

Abstract

Five C₁₀ iridoid glycosides (shanzhiside methyl ester, lamalbide, lamiide, sesamoside, and 5‐desoxysesamoside) were examined by electrospray ionization mass spectrometry (ESI‐MS). Considerable differences were observed in positive ion and negative ion mode. Only the positive ion spectra were useful for molecular mass determination on the basis of molecular alkali metal adducts, with the exception of two iridoids containing all 5β‐OH, 7β‐OH and 8β‐OH groups. Fragment characteristics for distinct functionalities were observed. Chelation studies of each iridoid with three different alkali metals were also conducted.     

Synthesis of Y3Al5O12:Eu2+ Phosphor by a Facile Hydrogen Iodide‐AssistedSol–Gel Method

Pure yttrium aluminum garnet (YAG) phosphor doped with Eu²⁺ has been successfully synthesized by a facile sol–gel method. The use of hydrogen iodide aimed to get Eu²⁺ ions, confirmed by X‐ray absorption near‐edge structure (XANES) analysis. Nearly spherical and well dispersed particles were synthesized. The produced YAG:Eu²⁺ phosphor powder had a broad emission band in the range of 400–600 nm with a peak at 480 nm, attributed to the allowed 4f⁷–4f⁶5d¹ transition of electrons in Eu²⁺ ions. The proposed method could also be expanded to prepare many other Eu²⁺‐doped phosphors with a solution method.