JOURNAL OF LUMINESCENCE
·
2021
·
IF 3.599
Jianxu Wang,Jiang Guo,Qiuyi Lv,Zhijiang Ma,Xuyao Feng,Yuhiu Lu,Jing Gao,Wensheng Chen,Bin Deng,Ruijin Yu
A series of novel orange-red emitting tungstate phosphors, Ca 3 La 2 W 2 O 12 (CLWO): x Sm 3+ (0.005 ≤ x ≤ 0.30) were successfully prepared through the solid-state method at high temperature. The space group is hexagonal R 3 ‾ m . Under 600 nm monitoring, a large charge transfer band from 250 to 340 nm composed of the electron transition of O 2- –Sm 3+ and O 2- –W 6+ and represented the strongest excitation at 300 nm. CLWO:Sm 3+ emitted orange-red light at 600 nm ( 4 G 5/2 – 6 H 7/2 ) under the strongest excitation of 300 nm. The intensity ratio of the electric-dipole and magnetic-dipole of all the samples were bigger than 1. With the Sm 3+ -doped concentration increasing, the upward tendency of ratio values originated from the increased degree of lattice distortion . The calculated R c (21.32 Å) and Q (3.78) represented the dipole–dipole interaction to account for the concentration quenching. With the temperature changing from 300 to 400 K, the chromaticity coordinates of samples just have a tiny difference (Δ x = 1.02 × 10 −4 , Δ y = 1.01 × 10 −4 ). The thermal activation energy was calculated to be 0.42 eV and T 0.5 > 480 K. The color purity of all the phosphors reached 98.9%. Ultimately, a white light-emitting diode (w-LED) was fabricated by coating trichromatic (red, blue, and green) phosphors on a near-ultraviolet chip. The fabricated w-LED revealed a high color rendering index (R a = 91, R 9 = 41) and a good chromaticity coordinate (0.320, 0.363) in the white area. Thus, these orange-red phosphors CLWO:Sm 3+ with high thermal stability and high color purity can be potentially used in w-LED applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
·
2021
·Vol. 36
·期 8
·1742-1749
·
IF 4.023
G. D. Lai,Y. L. Zhao,S. N. Luo,J. C. Shi
Four azoles with similar element percentages but different heterocyclic rings and functional groups are investigated with fs laser-induced breakdown spectroscopy (LIBS) as regards the influence of the interaction between the functional groups and heterocyclic rings on laser-induced plasma (LIP) emission. Temporally and spatially resolved measurements of the CN and C2 emissions are obtained and analyzed. The functional group affects the π-electron delocalization of the heterocyclic ring and consequently changes the dissociation pathways of the heterocyclic ring. At the early stage, CN is formed from the atomic recombination or native fragments, while at the late stage, through the remaining native fragments. In the whole plasma lifetime, C2 is mainly transformed from CN. Furthermore, dynamic CN and C2 distributions mediated by the laser-induced shock waves are discussed.
研究领域:
化学
·
物理学
✓ 已验证
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2021
·
IF 6.558
Yuchao Fu,Wanxiang Li,Haochen Li,Meizhen Huang
Electro-Fenton (EF) process is a significant water treatment method for the degradation of dissolved organic matter (DOM) in water and has been widely studied and applied in the past decade to degrade various dissolved organics. During water treatment , in order to monitor the degradation efficiency, it is in dire need to develop rapid and accurate methods that are favorable to assay on-line and on-site to provide feedback in a timely manner. UV–Visible absorption spectroscopy and Excitation-Emission Matrix (EEM) fluorescence spectroscopy techniques are most potential to realize on-line DOM measurement, but the measurement accuracy is unsatisfactory because of the obligatory involvement of iron-containing interferents. This study aims to simplify the measurement system complexity while overcoming the effect of iron-containing interferents during the measurement. An intrinsic relationship between the measured DOM concentration and the ultraviolet absorption at λ 1 and the light intensities of the fluorescence emission at λ 2 is derived theoretically and proved, based on which the influence of iron ions and their complexes on the spectrum can be eliminated, thus the content of DOM in the Electro-Fenton process is accurately determined. The proposed dual wavelength analysis with combination of fluorescence emission and ultraviolet absorption spectroscopy can achieve high precision ( R 2 = 0.9882 , R M S E = 0.0131 m g / L ). Furthermore, the on-line measurement design, called ultraviolet absorption-fluorescence emission dual wavelength analyzer, only includes one ultraviolet LED and two photodetectors. Its structure is simple and suitable for on-line monitoring DOM in EF process.
研究领域:
环境科学
·
水处理技术
✓ 已验证
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2024
·
IF 6.7
Tian Ren,Yao Lin,Yubin Su,Simin Ye,Chengbin Zheng
To meet the needs of food safety for simple, rapid, and low-cost analytical methods, a portable device based on a point discharge microplasma optical emission spectrometer (μPD-OES) was combined with machine learning to enable on-site food freshness evaluation and detection of adulteration. The device was integrated with two modular injection units (i.e., headspace solid-phase microextraction and headspace purge) for the examination of various samples. Aromas from meat and coffee were first introduced to the portable device. The aroma molecules were excited to specific atomic and molecular fragments at excited states by room temperature and atmospheric pressure microplasma due to their different atoms and molecular structures. Subsequently, different aromatic molecules obtained their own specific molecular and atomic emission spectra. With the help of machine learning, the portable device was successfully applied to the assessment of meat freshness with accuracies of 96.0, 98.7, and 94.7% for beef, pork, and chicken meat, respectively, through optical emission patterns of the aroma at different storage times. Furthermore, the developed procedures can identify beef samples containing different amounts of duck meat with an accuracy of 99.5% and classify two coffee species without errors, demonstrating the great potential of their application in the discrimination of food adulteration. The combination of machine learning and μPD-OES provides a simple, portable, and cost-effective strategy for food aroma analysis, potentially addressing field monitoring of food safety.
研究领域:
食品科学
·
分析化学
·
人工智能
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF LUMINESCENCE
·
2020
·
IF 3.28
Weimin Dong,Yingjie Sun,Qian Yao,Lintao Liu,Qingbo Wang,Hang Wen,Jing Li,Xinguang Xu,Jiyang Wang,Robert I. Boughton
Single crystal Pr(BO 2 ) 3 with centimeter size was grown successfully by a flux method using 3Li 2 CO 3 -2H 3 BO 3 as a flux. The absorption spectrum , emission spectrum , and luminescence lifetime of the Pr(BO 2 ) 3 crystal were measured. The crystal has a relatively large absorption cross section and full widths at half maximum (FWHM), which is advantageous for energy absorption from a pumping source. The spectrum parameters were calculated based on Judd–Ofelt (J-O) theory, and the effective J-O parameters were determined to be: Ω 2 = 37.47 × 10 20 cm 2 , Ω 4 = 6.80 × 10 20 cm 2 , and Ω 6 = 1.05 × 10 20 cm 2 . Furthermore, the emission cross section for the 3 P 0 → 3 F 2 transition at 650 nm was calculated to be 13.6 × 10 −19 cm 2 . The fluorescence lifetime of the 3 P 0 level was obtained to be 4.5 ns. The Raman spectrum of the crystal was also analyzed in detail. Physical properties such as thermal and chemical stability, hardness, and cleavage properties were explored. The refractive index and electronic structure were calculated by the first-principles method.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Mianhong Chen,Hua Fan,Zuizhi Lu,Jiayang Song,Xinguo Zhang,Qi Pang,Peican Chen,Liya Zhou
Stable and efficient broadband near-infrared (NIR) emitting phosphors are vital for the next-generation NIR sources. However, it still remains challenging to construct such phosphors, particularly those with a NIR-II window. In this work, using the Cr 3+ -Yb 3+ energy transfer (ET) strategy, the as-synthesized Ca 2 ScTaO 6 :Cr 3+ , Yb 3+ phosphor retains 86.2% of the initial luminescence intensity of Yb 3+ at 373 K with characteristic emissions of both activators ranging from 700 nm to 1200 nm. The occupation of Cr 3+ into both Ta 5+ and Sc 3+ sites is confirmed by X-ray diffraction, time-resolved emission spectrum, and crystal structure. The efficient ET from Cr 3+ to Yb 3+ is revealed by the diffuse reflection spectrum, steady-state and transient fluorescence. As a result, it contributes to the excellent performance of the phosphor. Based on the optimized phosphor, a NIR light-emitting diode is fabricated and demonstrated its advantage in imaging and potential application in information encryption. The result highlights ET as a robust strategy to construct efficient NIR phosphor.
研究领域:
材料科学
·
光学
·
光子学
·
固体物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Zhaoyang Wang,Yinshan Zhang,Yanhua Shi,Zhinmin Dong,Yuanping Jiang,Qian Liu,Zifan Li,Yuhui Liu,Xiaohong Cao,Yingcai Wang,Zhibin Zhang,Yunhai Liu
The main purpose of this paper is to study the extraction and separation of key fragment elements based on the electrolytic refining process of spent fuel dry reprocessing. Firstly, the electrochemical mechanisms of Er(III) and Yb(III) in LiCl-KCl molten salts were investigated on W and In film electrodes with applied cyclic voltammetry (CV), square wave voltammetry (SWV) and open circuit potential (OCP) at 773 K. The results indicated that the reduction behaviour of In(III) and Yb(III) ions were a two-step transfer process and Er(III) ions was a one-step transfer process. Then, the kinetic parameters in electrochemical processes were calculated on an In electrode with different temperatures. The OCP approach was used to determine the equilibrium potential of Er(III)/Er(0) in the temperature range of 773 K∼848 K, and thermodynamic parameters of the In 3 Er alloy were provided. Based on electrochemical behaviour results, the electrochemical extraction of Er(III) and Yb(III) from LiCl-KCl-ErCl 3 molten salts and LiCl-KCl-YbCl 3 molten salts at liquid In electrodes was performed by constant potential and constant current electrolysis, respectively. The electrolysis products were determined by X-ray diffraction (XRD), scanning electron microscopy and energy dispersive spectrometry (SEM-EDS), the primary intermetallic compounds generated in the alloys were In 3 Er and In 3 Yb. The average extraction rates for Er(III) and Yb(III) were 94.70% and 96.54%, respectively, according to inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis. Er(III) and Yb(III) were selectively extracted and separated from LiCl-KCl-ErCl 3 -YbCl 3 molten salts by potentiostatic control on the basis of the previously studied Lns (Er and Yb) extraction on In electrodes. The separation rate of Er(III) and Yb(III) by electrochemical selective deposition was 94.21%.
研究领域:
电化学
·
材料科学
·
核工程
·
热力学
·
动力学
✓ 已验证
DOI
高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2023
·Vol. 332
·期 4
·1353-1365
·
IF 1.6
Wang Zhaoyang,Shen Yubo,Zhang Yinshan,Liu Yuhui,Dong Zhimin,Quan Meiyang,Yu Fengtao,Cao Xiaohong,Zhang Zhibin,Wang Yingcai,Liu Yunhai
In order to improve the utilization of spent fuel, electrolysis is used to recover fissile elements from nuclear waste samarium. The electrochemical behaviors of Sm(III) and Pb(II) were examined by CV, SWV, and OCP techniques in LiCl–KCl molten salts at 773 K. The redox mechanism of Sm(III) ions on the liquid Pb thin film electrode was analyzed. The results demonstrate that Sm(III) electro-reduction at the inert W electrode only occurred in a soluble–soluble electrochemical transition Sm(III)/Sm(II). Additionally, the kinetic parameters of samarium and lead ions were computed. The activation energies of diffusion for Sm(III) and Pb(II) were 32.92 kJ mol −1 and 35.21 kJ mol −1 , respectively. SmPb 3 and Sm 2 Pb intermetallic compounds were derived using constant potential electrolysis and constant current electrolysis at the Pb electrode in a molten salt system. The cathodic deposition output was characterized by XRD and SEM–EDS. The ICP-AES results showed that the average extraction ratio of Sm on the Pb electrode was about 94.23%.
研究领域:
核化学
·
电化学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）