Green emitting NaCl:XTb [ X = 0.0, 0.002, 0.004, 0.006, 0.008, 0.01 and 0.02] single crystals were grown by adopting the Czochralski method and their structural, mechanical and optical properties were studied by carrying out X-ray diffraction (XRD), micro-hardness, optical absorption, photoluminescence (PL), thermoluminescence (TL), etc. measurements. XRD results revealed the absence of lattice distortion due to doping with Tb ions. Hardness analysis displayed more hardness for the Tb-doped crystals than for the pure NaCl crystal. Optical absorption spectra confirmed five main peaks corresponding to 4f8 & RARR;4f75 d1(8S) and 7F6 & RARR;5LJ=9,10 transitions of the Tb3+ ions. PL emission spectra (excitated at 372 nm) indicated the maximum intensity peak at 545 nm corresponding to 5D4 & RARR;7F5 transition of the Tb3+ ions. The emission peak intensity was found to increase with the increase in Tb concentration; and the CIE coordinates of NaCl:0.02 Tb were found as x = 0.3008 and y = 0.5000, located in the green region. TL glow curves exhibited higher intense peaks for the NaCl:0.02 Tb crystal irradiated with & gamma;-ray; the peak parameters (E, s, & mu;g and b) were also estimated. Dose response and energy storage stability of the NaCl:0.02 Tb crystal irradiated with & gamma;-ray were studied for dosimetry application. The research results show that the NaCl:Tb crystal would be potential candidates for the WLEDs and TLD applications.

The NaCl:XEu (with X = 0.0, 0.002, 0.004, 0.006, 0.008, 0.01, 0.02 and 0.04) crystals have been grown in air by the melt (Czochralski) method and have investigated the Eu concentration dependence of the structural, physical and optical (optical absorption, photoluminescence and thermo-luminescence) properties by using the available characterization techniques. X-ray diffraction and photoluminescence (PL) studies on the doped crystals have confirmed the presence of Eu ions (existing as Eu2+ and Eu3+ ions) in the NaCl crystal matrix. Hardness measurement has shown that the Eu doped crystals belong to the hard material category and the hardness and elastic stiffness constant decrease with the load increase and increase with the Eu concentration increase. Optical absorption spectra have revealed that five new peaks appear on doping with Eu ions. PL spectra have shown increase in emission intensity with the increase in concentration of Eu2+ and Eu3+ ions. Thermo-luminescence (TL) glow curves exhibit two peaks at similar to 103.7 and similar to 199.9 degrees c. The TL peak intensities observed for the Eu doped NaCl crystals are much larger than the pure NaCl crystal. NaCl:XEu crystal with X = 0.008 has been found to possess the optimal luminous (both PL and TL) properties. The TL parameters calculated prove that the activation energy (E) values vary with the Eu concentration and the trap concentration (n(0)) values of the high temperature peak are larger than that for the low temperature peak. (C) 2022 Published by Elsevier B.V.

KCl0.5Br0.5:XPr3+ [X = 0.0 (pure KCl0.5Br0.5), 0.002, 0.004, 0.006, 0.008, 0.01, 0.02 and 0.04] crystals were successfully grown by Czockralski (Cz) pulling method and the structural, mechanical and optical properties of crystals were thoroughly investigated. X-ray diffraction (XRD) and X-ray photoelectron spectroscopic (XPS) studies indicated that the Pr ions have been incorporated into the KCl0.5Br0.5 host lattice and existed mainly as trivalent Pr. UV-Vis absorption spectra showed that the presence of peaks at 211, 227, 293, 457, 479, 494 and 601 nm. Hardness was found to increase with increasing of in Pr3+ concentration and indentation load, the hardness of the Pr doped crystals were larger than the un-doped crystal and the reverse indentation size effect was observed. The intensity of photoluminescence (PL) peaks was strongly depended on the Pr(3+)concentration. thermo-luminescence (TL) glow curves exhibited one peaks at 63-76 degrees C, indicating that one kind of trap existed in the crystals. The optimal luminous (both PL and TL) properties the KCl0.5Br0.5:XPr3+ crystals were obtained at X = 0.006. These results indicated that the KCl0.5Br0.5:Pr3+ crystals could be considered as a promising candidate for their use in optical and dosimetry applications.

The pure and Eu2+-doped NaCl crystal were successfully grown by the melt (Czochralski) method. The structural, mechanical and optical properties were characterized by carrying out X-ray diffraction (XRD), micro-hardness, optical absorption, photoluminescence (PL) and thermoluminescence (TL) measurements. The XRD analysis indicates that the Eu2+ ions have been incorporated into the NaCl crystal matrix and the diffraction peak shifts toward lower 2θ angle. Hardness measurement has shown a decrease of crystal hardness with indentation load. Optical absorption spectrum has shown the presence of peaks at 211, 224, 231, 255, 320 and 352 nm. Results of PL analysis indicate that the emission peak exists the characteristic peak of bivalent Eu ions corresponding to the t2g(4f65d) → 8S7/2(4f7) transition. The TL glow curve of NaCl:Eu2+ crystal has shown two peaks located at 108.6 and 199.6 °C with different trap depth, the intensity of the high-temperature peak is found to be larger than the low-temperature one.

采用电阻加热Czochralski法和一控双变技术,在最佳工艺参数(转速:6 r/min～8 r/min;拉速:1 mm/h～2 mm/h;循环水温度:28℃ ±1℃;降温速率:8℃/h～10℃/h;轴向温度梯度:1℃/mm～2℃/mm)条件下,生长出了Φ96 mm×30 mm的KBr晶体.分析了晶体的潮解机理,采用饱和溶液对KBr晶体进行抛光,分析抛光压力、抛光盘转速、抛光液流量和抛光时间对晶体表面去除率和粗糙度的影响,得到最佳的抛光参数:最佳压力为0.1042 MPa、抛光液流量为15 mL/min、抛光盘转速为30 r/min和抛光时间为20 min.对抛光后的晶体元件透过性能测试表明,厚度为4 mm晶体的透过率为90.2％,在透过波段存在一定吸收.

Large-sized KCl0.5Br0.5:XCe3+ crystals doped with different Ce concentrations (with X = 0.0-0.05) were successfully grown by the melt (Czochralski) method. The structural, mechanical, electrical and optical properties were measured by carrying out X-ray diffraction (XRD), micro-hardness, direct current (DC)/ alternating current (AC) electrical, optical absorption, photoluminescence (PL) and thermo-luminescence (TL) measurements. XRD analysis indicates the incorporation of Ce3+ ions into the KCl0.5Br0.5 crystal matrix. Hardness analysis shows that their values increase with the increase in crystal length and Ce3+ concentration. Electrical measurements indicate an increase of DC/AC electrical conductivity, dielectric loss factor and dielectric constant with the increase in Ce3+ concentration and temperature. Optical absorption spectra have shown that the excitation and emission peaks are strongly influenced by the Ce3+ concentration. The X-ray photoelectron spectroscopy (XPS) data-correlated luminescence (both PL and TL) have revealed that Ce3+ is the dominant state of cerium to be optimal for large area electronic devices and clinical dosimetry applications. (C) 2021 Published by Elsevier B.V.

In order to investigate the effect of cooling time on the properties of crystal formed directly on cooling the melt, we have prepared the KCl1−xBrx crystals [with x = 0.0 (pure KCl), 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0 (pure KBr)] by cooling their melts directly with different cooling times (0, 2, 4, 6, 8, 10, 12 and 14 h) in each case. The prepared crystals have been characterized structurally, optically, mechanically, thermally and electrically by carrying out X-ray diffraction (XRD), atomic force microscopic (AFM), optical absorption, micro-hardness, specific heat capacity and electrical conductivity measurements. XRD analysis indicates halite structure for all the crystals formed. AFM results show an increase of grain size with the cooling time. Optical absorption spectra obtained have illustrated the presence of peak at 229 nm for the KCl crystal and 342.2 nm for the mixed crystals, the peak gradually shifts to shorter wavelengths with the increase of cooling time. Hardness analysis shows nonlinear variation with the cooling time, KCl0.5Br0.5 crystal having the maximum value when the cooling time is 4 h. Temperature and composition have influences on the thermal conductivity, specific heat capacity and thermal diffusivity, while the cooling time has a little influence on the thermal performance. Electrical conductivity measurement indicates a little influence of cooling time and strong influences of temperature and composition on the electrical conductivity and activation energy.

A high-quality KCl0.5Br0.5 crystal has been grown by using the resistance heating Czochralski (Cz) method under the best process parameters (rotating speed: 6–8 r/min, pulling speed: 1–2 mm/h, circulating water temperature: 28 ± 1 °C, cooling rate: 8–10 °C/h, and axial temperature gradient: 1–2 °C/mm). The deliquescence analysis of the KCl0.5Br0.5 crystal indicates that the deliquescence of KCl0.5Br0.5 crystal strongly depends on the temperature and humidity and the deliquescence of the crystal has been proved to be a physical process by carrying out X-ray diffraction (XRD), atomic force microscopic (AFM), and energy dispersive X-ray spectroscopic (EDX) measurements. The results of the polishing fluid composition experiment have shown that the best polishing fluid composition is ‘water + ethanol + surfactant X’, and the best ratio between them is 87.5:9.5:3.0. The effects of polishing pressure, polishing disk speed, polishing fluid flow rate, and polishing time on the removal rate and roughness of the KCl0.5Br0.5 crystal surface have been analyzed. The best parameters found for the crystal processing are the optimal pressure is 0.1042 MPa, the polishing fluid flow rate is 15 ml/min, the rotating speed of the polishing disk is 30 r/min, and the polishing time is 20 min. The performance test of the polished crystal element has shown that the transmittance of the crystal with a thickness of 4 mm is 91.7%, and the surface roughness of the crystal is 3.96 nm. Results obtained in the present study provide the technical route and experimental support for the processing of soft and moisture-prone crystals.

Large-sized single crystals of NaxK1-xCl:0.01Ce3+ (with x = 0.2, 0.4, 0.5, 0.6 and 0.8) have been grown by the Czochralski method. The structural, mechanical, electrical and optical properties were characterized by carrying out X-ray diffraction (XRD), X-ray photoelectron spectroscopic (XPS), micro-hardness, DC/AC electrical, optical absorption and luminescence measurements. XRD analysis indicates the two-phased (with two f.c.c. lattices) nature of the mixed crystals and the incorporation of Ce3+ ions into the NaxK1-xCl crystal matrix. XPS analysis has verified the dominant presence of Ce3+ (over Ce4+) ion in the NaxK1-xCl crystal matrix. Hardness measurement has shown an increase of crystal hardness with Ce3+ doping and maximum hardness for the Na0.5K0.5Cl:0.01Ce3+ crystal. Electrical measurements indicate that the DC/AC electrical conductivity, dielectric loss factor and dielectric constant of Ce3+ doped crystals increase with the increase in temperature and are larger than that for the un-doped Na0.5K0.5Cl crystal. Four peaks at 203, 215, 290 and 344 nm are shown by the optical absorption spectra. Photoluminescence excitation and emission peaks due to Ce3+ (4f <-> 5d) transitions have got influenced by the Ce3+ doping. The TL glow curves of NaxK1-xCl:0.01Ce3+ crystals obtained show two peaks at about 72 and 174 degrees C, Ce3+ ions produce suitable trap depth and result in the characteristic emission. The Na0.5K0.5Cl:Ce3+ crystal is found to exhibit maximum PL and TL performances. Results obtained indicate that the NaxK1-xCl:Ce3+ crystals grown can find their use in luminescence, capacitor and thermoluminescence dosimeter applications.

采用电阻加热Czochralski法和坩埚底部补偿技术,在优化温场和工艺参数后,生长出了φ130 mm×100 mm的NaCl单晶.XRD分析表明,NaCl晶体为立方晶系,晶格常数为a=0.56402 nm.晶体的透光性能测试表明:厚度4 mm的样品的透过率大于91.5％;晶体的Virckers硬度为21.52 kg/mm2,硬度系数为1.672,证明NaCl晶体是一种软质材料;晶体的光学均匀性随着位错密度的增加而降低;热释光发光(TL)曲线表明,NaCl晶体的发光峰位于74.35℃和221.14℃,后者的发光强度是前者的5倍以上,表明NaCl晶体是一种可用于剂量测定和红外领域的优质材料.

The synthesized (E)-3-(benzofuran-2-yl)-2-(thiophen-2-yl)acrylonitrile (TACNBNF) crystal compound was characterized using FT-IR, H-1 and C-13 NMR analyses, ESI-mass and photoluminescence studies. Single crystal X-ray diffraction investigations reveal that the molecule is associated with the C (7)-H (7)center dot center dot center dot S (1) donor-acceptor hydrogen bond interaction. The bond angle at C7 gives a strong indication that H7 center dot center dot center dot S1 contact is repulsive. However, the C5-C7-C8 bond angle = 128.8 (2) degrees, is distorted due to strain induced by double bond linkage at C5=C7. The computational work such as optimized geometry by Density functional theory (DFT), FT-IR, Molecular electrostatic potential (MEP), Frontier Molecular orbitals (FMOs), Mulliken's population analysis, Nonlinear optical effects (NLO), and Natural bond orbitals (NBO) were analyzed with the aid of Gaussian 03 program using basic set B3LYP/6-311++G (d,p). The proton H-1 and carbon C-13 NMR chemical shifts of molecules were simulated by the gauge-independent atomic orbital (GIAO) manner and also compared with experimental H-1 and C-13 NMR results. The in vitro antioxidant study was carried out in DPPH assay ascorbic acid, a standard drug. The in silico molecular docking, ADMET and toxicity studies were performed by Discovery Studio 4.0. (C) 2019 Elsevier B.V. All rights reserved.

Large-sized Ce 3+ doped KBr crystal was grown using the resistance heating Czochralski method. The material has more well-defined optical and mechanical properties than the pure KBr single crystal. The structural, optical properties and quality of the grown KBr:Ce 3+ crystal were investigated by x-ray diffraction (XRD), optical absorption, photoluminescence (PL), PL excitation spectroscopy, micro-hardness and stress measurements. The XRD data indicated that the KBr host lattice changed when Ce ions were incorporated. Optical absorption and PL measurements confirmed the presence of cerium ions in the doped KBr crystal. A broad and intense blue emission around 394 nm, attributable to the transition from the 5 d excited state to the 4 f ground state of the Ce 3+ ions, was observed in the PL emission. The hardness of the KBr:Ce 3+ crystal was greater than that of the pure KBr crystal. The stress values of different parts in the crystal were different, and the stress was mainly dependent on the process parameters. High stresses were always found to exist near the growth interfaces, at the shoulder-expanding locations, the tailing locations and the sites where the diameters undergo sharp changes. The optimized process parameters were the main measures to avoid the crack of the large-sized KBr:Ce 3+ crystal. These observations indicate that the KBr:Ce 3+ crystal is a promising material for use in optical, dosimetry and scintillation applications.

The quasi‐lattice model of NaCl melt is proposed by the ion movement characteristics, melt structure, and radial distribution function of ions, which is composed of regular and irregular regions. These regions are connected by an irregular interface with a thickness of several sublayers, and the ions on the interface are continuously and rapidly transferred. The mixed transmission kinetic equation of NaCl melt is analyzed theoretically by using the heat transfer equation and hydrodynamic equation. The liquid flow effect of NaCl melt and the temperature distribution in crystal are analyzed according to the numerical results. It is found that the shape of a solid–liquid interface will change with the rotation rate or diameter increase. The related properties of the NaCl melt are calculated. These studies of the NaCl melt provide theoretical support to a further study on crystal growth, other alkali halide, and alkaline earth metal halide melt.

The title compound (DPTA) synthesized by Knoevenagel Condensation process, was developed from a single crystal by slow evaporation method. This compound was then confirmed by FT-IR and FT-Raman spectroscopic analyses in order to identify the function groups. UV–visible spectral studies and fluorescence spectroscopic analysis were also carried out for the grown crystal. Density Functional Theory (DFT/B3LYP/6-311G++(d,p) level of theory) was performed by Gaussion 09 software. Further, the single crystal XRD analysis was used to confirm the crystal system and lattice parameters. Moreover, structural perfection of the grown crystal was analysed by high resolution X-ray diffraction (HRXRD) rocking curve measurements. The chemical composition was confirmed by performing elemental chemical analysis as well 1H NMR and 13C NMR spectroscopic studies. The optical studies further carried out, revealed the optical band gap and the refractive index of the material, measured as a function of wavelength. The laser damage threshold of the grown crystal was then measured using Nd:YAG laser. The dielectric constant, dielectric loss and a.c conductivity of (DPTA) was investigated with different frequencies and temperatures. Moreover, the magnetic property of the grown crystal was evaluated by VSM analysis.

The sapphire wafer was grinded and polished by different particle size of the B4C abrasive including W28 and W7. The influence of B4C abrasive with different particle size on the removal rate, roughness, flatness, bending degree and warpage of sapphire wafer were investigated. The results show that the abrasives of W28 and W7 have different polishing performances. Under the same processing conditions, the removal rate of B4C is higher than that of W28. However, the roughness of the sapphire wafer with W28 is greater and the grinding damage layer is deeper (i.e., Ra=1.319 nm, and Rt=2.584 nm). The removal rate of W7 is lower, the damage layer is removed (i.e., Ra=0.194 nm, and Rt=0.361 nm), the surface quality is high, which is suitable for finishing flatness, after removal of 20 μm. The surface roughness of the finished sapphire wafer is better than that of W28.

In order to understand the effect of forming hybrid crystals by doping with metallic impurities or by quasi mixing on the physicochemical properties of the basic material crystal, we have grown by the free evaporation method at room temperature and characterized (chemically, structurally, optically and electrically) un-doped and K+/Ca2+/Mn2+/Mg2+/Cu2+ doped (with 1 mol% concentration) ZnCd(SCN)(4) and ZnxCd(2-x)(SCN)(4) (with x = 0.0, 0.4, 0.8, 1.2, 1.6 and 2.0) single crystals. Single crystals could be grown with x = 0.0 (leading to Cd(SCN)(2)) but not when x = 2.0 (leading to Zn(SCN)(2)). Results obtained in the present study through X-ray diffraction and EDAX spectral measurements indicate the formation of the above hybrid crystals. The optical (UV-Vis-NIR spectral and SHG efficiency) measurements indicate significant changes in optical transmittance and SHG efficiency due to doping as well as quasi mixing. Dielectric measurements made in the temperature range 40-150 degrees C with a fixed frequency of 1 kHz indicate a normal dielectric behavior for all the eleven crystals grown. Moreover, the present study indicates an increase of dielectric constant and SHG efficiency when ZnCd(SCN)(4) crystal is doped with a metallic impurity whereas a decrease of dielectric constant and SHG efficiency when quasi mixing is done. (C) 2018 Elsevier B.V. All rights reserved.