Isolated Solid-State Packaging Technology of High-Temperature Pressure Sensor

The principle of miniature isolated solid-state encapsulation technology of high-temperature pressure sensor and the structure of packaging are discussed, including static electricity bonding, stainless steel diaphragm selection and rippled design, laser welding, silicon oil infilling, isolation and other techniques used in sensor packaging, which can affect the performance of the sensor. By adopting stainless steel diaphragm and high-temperature silicon oil as isolation materials, not only the encapsulation of the sensor is as small as 15 mm in diameter and under 1 mA drive, its full range output is 72 mV and zero stability is 0.48% F.S/mon, but also the reliability of the sensor is improved and its application is widely broadened.

Fabrication of YAG:Ce^(3+) and YAG:Ce^(3+),Sc^(3+) Phosphors by Spark Plasma Sintering Technique

In this study,a single-doped phosphors yttrium aluminum garnet(Y_(3)Al_(5)O_(12),YAG):Ce^(3+),single-doped YAG:Sc^(3+),and double-doped phosphors YAG:Ce^(3+),Sc^(3+) were prepared by spark plasma sintering(SPS)(lower than 1 200℃).The characteristics of synthesized phosphors were determined using scanning electron microscopy(SEM),X-ray diffraction(XRD),and fluorescence spectroscopy.During SPS,the lattice structure of YAG was maintained by the added Ce^(3+) and Sc^(3+).The emission wavelength of YAG:Ce^(3+) prepared from SPS(425-700 nm) was wider compared to that of YAG:Ce^(3+) prepared from high-temperature solid-state reaction(HSSR)(500-700 nm).The incorporation of low-dose Sc^(3+) in YAG:Ce^(3+) moved the emission peak towards the short wavelength.

Effect of Dopant Concentration on Luminescence Properties of KCaPO4:Sm

KCaPO4 doped with different concentrations of Sm was synthesised by a high-temperature solid-state method, and the crystal structure, morphology, TL and OSL properties of Sm-doped KCaPO4 were systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermoluminescence (TL), and optically stimulated luminescence (OSL) techniques. The results show that 0.3 mol% Sm-doped KCaPO4 annealed at 1073 K for 1 h has the highest TL intensity, and thus is expected to be a candidate material for thermoluminescence dosimetry applications.

Synthesis, Crystal Structure and Chemical Bonding of a New Binary Lu-Sn Phase: Lu_(11)Sn_(10)

A new tetragonal phase of LunSnl0 is obtained from high temperature reaction of the pure elements in a welded tantalum tube. Its crystal structure was established by single-crystal X-ray diffraction. Lu11Sn10 crystallizes in the tetragonal space group 14/mmm （No. 139） with a = 11.2953（18）, c = 16.424（4） A, V= 2095.5（7）A3, Z= 4, Mr = 3111.57, Dc = 9.863 g/cm^3, p = 62.897 -1 mm , F（000） = 5124, and the final R = 0.0348 and wR = 0.0894 for 706 observed reflections with 1 〉 2σ（I）. The structure of LullSnl0 may be derived from the HonGel0 structural type. It is isostructural with DyllSn10, featuring a three-dimensional （3D） framework composed of [Sn4] squares and [Sn2] dimers interlinked via Sn-Sn bonds with two types of one-dimensional （1D） tunnels along the c-axis, which are occupied by isolated Sn atoms, [Sn2] dimers and all the Lu atoms Band structure calculation based on density functional theory method indicates that LUllSn10 is metallic.

Synthesis,Crystal Structure,Physical Properties and Theoretical Studies of the New Ternary Sulfide with Closed Cavities:CsYb_7S_(11)

A novel ternary rare-earth sulfide, CsYb7S（11）, has been successfully synthesized by high-temperature solid-state reaction of an elemental mixture with modified Cs Cl flux. The single-crystal X-ray diffraction data reveal its orthorhombic symmetry in space group Cmca（no. 64） with a = 15.271（3）, b = 13.414（2）, c = 18.869（3） A°, V = 3865.2（2） A°^3, Z = 8, Mr = 1696.85, Dc = 5.832 g/cm^3, μ = 36.538 mm^-1, F（000） = 5768, the final R = 0.0225 and w R = 0.0517 for 2258 observed reflections with I 〉 2σ（I）, 2.67〈θ〈27.48o, w = 1/[σ^2（Fo^2） ＋（0.0443 P）2 ＋ 8.7453 P], where P =（Fo^2 ＋ 2Fc^2）/3, S = 1.036,（Δρ）max = 1.609 and（Δρ）min = –1.922. The remarkable structural feature is the dual tricapped Cs2@S18 cube closed cavities far apart within the three-dimensional [Yb7S（11）]-covalent bonding matrix. Magnetic susceptibility measurements show that the title compound exhibits temperature-dependent（50～300 K） para-magnetism and obey the Curie-Weiss law. Moreover, the optical gap of 2.03 Ev for CsYb7S11 was deduced from the UV/Vis reflectance spectroscopy and DFT study indicates an indirect band gap with an electronic transfer excitation of S-3p to Yb-5d orbital.

Synthesis,Crystal Structure,and Optical Property of Zero-dimensional Quaternary Thioborate：Ba9B3GaS15

A new zero-dimensional（0D） thioborate Ba_9B_3GaS_（15） has been discovered by conventional high-temperature solid-state reaction. The compound crystallizes in orthorhombic space group Pbca with a = 8.4759（8）,b = 22.266（2）,c = 31.426（3） ？,V = 5931（2） ？~3,Z = 8,Mr = 1819.11,Dc = 4.075 g/cm3,μ = 13.684 mm^（-1）,F（000） = 6320,S = 1.034,（Δρ）max = 5.039,（Δρ）min = –5.409 e/？~3,the final R = 0.0362 and w R = 0.1053 for 19243 observed reflections with I 〉 2σ（I）. The structure is constructed by discrete [BS_3]^（3–） trigonal planes and isolated [GaS_4]^（5–） tetrahedra with Ba^（2＋） and isolated S^（2–） filled among them. The UV-Vis-near-IR spectrum reveals a wide band gap of 3.15 eV that agrees with the electronic structure calculation.

Probing thermally-induced structural evolution during the synthesis of layered Li-, Na-, or K-containing 3d transition-metal oxides

Layered alkali-containing 3d transition-metal oxides are of the utmost importance in the use of electrode materials for advanced energy storage applications such as Li-,Na-,or K-ion batteries.A significant challenge in the field of materials chemistry is understanding the dynamics of the chemical reactions between alkali-free precursors and alkali species during the synthesis of these compounds.In this study,in situ high-resolution synchrotron-based X-ray diffraction was applied to reveal the Li/Na/K-ion insertion-induced structural transformation mechanism during high-temperature solid-state reaction.The in situ diffraction results demonstrate that the chemical reaction pathway strongly depends on the alkali-free precursor type,which is a structural matrix enabling phase transi-tions.Quantitative phase analysis identifies for the first time the decomposition of lithium sources as the most critical factor for the formation of metastable intermediates or impurities during the entire process of Li-rich layered Li[Li_(0.2)Ni_(0.2)Mn_(0.6)]O_(2) formation.Since the alkali ions have different ionic radii,Na/K ions tend to be located on prismatic sites in the defective layered structure(Na_(2/3-x)[Ni_(0.25)Mn_(0.75)]O_(2) or K_(2/3-x)[Ni_(0.25)Mn_(0.75)]O_(2))during calcination,whereas the Li ions prefer to be localized on the tetrahedral and/or octahedral sites,forming O-type structures.

Dimensionality Reducing from Three-dimensional RbLu5Te8 to Two-dimensional CsMnGdTe3:Syntheses,Crystal and Electronic Structures

Two new rare-earth metal chalcogenides,namely RbLu5Te8 and CsMnGdTe3,have been successfully synthesized under high-temperature solid-state reaction conditions and structurally characterized by single-crystal X-ray diffraction analysis.RbLu5Te8 belongs to the monoclinic space group C2/m(no.12)with two formula units in a unit cell:a=22.075(5),b=4.2987(8),c=10.588(2)A,β=103.89(2)°,V=975.4(4)A3,whereas CsMnGdTe3 crystallizes in the orthorhombic space group Cmcm(no.63)with four formula units in a unit cell:a=4.4872(8),b=16.769(3),c=11.807(2)A and V=888.4(3)A3.In the structure of RbLu5Te8,face-,edgeand vertex-sharing[LuTe6]octahedra are interconnected to produce a three-dimensional(3D)framework with Rb^+lying in the tunnels.The crystal structure of CsMnGdTe3 consists of two-dimensional(2D)[MnGdTe3]^–layers of edge-and vertex-sharing[GdTe6]octahedra with Mn atoms filling the tetrahedral interstices,which stack along the b-axis.The Cs atoms are located between the[MnGdTe3]^–layers and surrounded by eight Te atoms to form a[CsTe8]bicapped trigonal prism.Moreover,theoretical studies have aided the understanding of their electronic structures.