Photoluminescence of rare earth ions coactivated Ca₉Y(VO₄)₇ with cold, natural and warm white emission

Li, Ling,Liu, Xiaoguang,Noh, Hyeon Mi,Moon, Byung Kee,Choi, Byung Chun,Jeong, Jung Hyun Elsevier 2015 Materials chemistry and physics Vol.158 No.-

<P><B>Abstract</B></P> <P>It has been still a challenge to obtain a new single-component white-light phosphor with the vanadates as host lattices and with two types of ions as activators. A systematic Ln<SUB>1</SUB> <SUP>3+</SUP>/Ln<SUB>2</SUB> <SUP>3+</SUP> (Ln<SUB>1</SUB> <SUP>3+</SUP>/Ln<SUB>2</SUB> <SUP>3+</SUP> = Dy<SUP>3+</SUP>/Tm<SUP>3+</SUP> or Dy<SUP>3+</SUP>/Sm<SUP>3+</SUP> or Dy<SUP>3+</SUP>/Eu<SUP>3+</SUP> or Tm<SUP>3+</SUP>/Eu<SUP>3+</SUP> or Tm<SUP>3+</SUP>/Sm<SUP>3+</SUP>) coactivated Ca<SUB>9</SUB>Y(VO<SUB>4</SUB>)<SUB>7</SUB> (CYV)samples as well as their singly doped CYV phosphors have been synthesized by the traditional solid state reaction and their photoluminescence properties have been investigated. The photoluminescence properties as a function of the concentration of rare earth ions have been discussed and the tunable luminescent color was found. The warm (CYV: 1%Dy<SUP>3+</SUP>, 1%Sm<SUP>3+</SUP>), natural (CYV: 7% Tm<SUP>3+</SUP>,0.5% Eu<SUP>3+</SUP>; CYV: 1.0% Tm<SUP>3+</SUP>, 0.5% Sm<SUP>3+</SUP>), and cold (CYV: 3% Tm<SUP>3+</SUP>,0.5% Eu<SUP>3+</SUP>; CYV: 0.5% Dy<SUP>3+</SUP>,0.5% Tm<SUP>3+</SUP>; CYV: 0.5% Dy<SUP>3+</SUP>,0.7% Tm<SUP>3+</SUP>; CYV: 0.3%Dy<SUP>3+</SUP>, 0.5% Tm<SUP>3+</SUP>) white lights can be obtained. Generally, the emission intensity or lifetime of one rare earth ions decreases with increasing of the concentration of another rare earth ions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Photoluminescence properties of rare earth ions coactivated Ca<SUB>9</SUB>Y(VO<SUB>4</SUB>)<SUB>7</SUB> were investigated. </LI> <LI> The effects of rare earth ions concentration on photoluminescence have been discussed. </LI> <LI> The tunable luminescent color was found. </LI> <LI> Cold, natural and warm white emissions were obtained. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Spontaneous Sm³⁺→Sm²⁺ reduction ability of MAl₂Si₂O₈ (M = Sr, Ba): Sm

Li, Ling,Wang, Wenjun,Pan, Yu,Liu, Xiaoguang,Noh, Hyeon Mi,Jeong, Jung Hyun ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.723 No.-

<P><B>Abstract</B></P> <P>In air atmosphere, the spontaneous reduction abilities of Sm<SUP>3+</SUP>→Sm<SUP>2+</SUP> in Sm ions doped monoclinic SrAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (SASO) and BaAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (M-BASO) as well as hexagonal BaAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (H-BASO) are investigated. Sm ions doped MAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (M = Sr, Ba) samples were synthesized using Pechini-type sol-gel technology and sintered in air atmosphere and reducing condition, respectively. By comparing the photoluminescence properties of Sm doped MAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (M = Sr, Ba) calcined in air with that in reducing condition, the spontaneous reduction of Sm<SUP>3+</SUP>→Sm<SUP>2+</SUP> can be detected only in the host lattice H-BASO. The essential that makes the reduction of Sm<SUP>3+</SUP> to Sm<SUP>2+</SUP> was investigated by calculating their chemical bonds parameter quantitatively. The important key environmental factor of Ba<SUP>2+</SUP> in H-BASO is the largest among the three samples MAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB>. It indicates that the hexagonal H-BASO sample is the easiest one to realize the spontaneous reduction of Sm<SUP>3+</SUP>→Sm<SUP>2+</SUP> among Sm doped MAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (M = Sr, Ba) samples. The needed energy transferring one electron of the ligand to the central ions Sm<SUP>3+</SUP> in H-BASO:Sm is the lowest. The theoretical analysis agrees well with the experimental result. Our work provides with the theoretical and experimental foundation for the spontaneous reduction of trivalent samarium in the crystals.</P> <P><B>Highlights</B></P> <P> <UL> <LI> In air atmosphere, the PL properties of Sm<SUP>3+</SUP> in MAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB>:Sm are investigated. </LI> <LI> The abnormal Sm<SUP>3+</SUP>→Sm<SUP>2+</SUP> reduction can be detected only in the hexagonal BaAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB>. </LI> <LI> The reduction essential was determined by calculating the chemical bond parameters. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Comparison between Craniospinal Irradiation and Limited-Field Radiation in Patients with Non-metastatic Bifocal Germinoma

Bo Li,Wenyi Lv,Chunde Li,Jiongxian Yang,Jiajia Chen,Jin Feng,Li Chen,Zhenyu Ma,Youqi Li,Jiayi Wang,Yanwei Liu,Yanong Li,Shuai Liu,Shiqi Luo,Xiaoguang Qiu 대한암학회 2020 Cancer Research and Treatment Vol.52 No.4

Purpose Whether craniospinal irradiation (CSI) could be replaced by limited-field radiation in non-metastatic bifocal germinoma remains controversial. We addressed the issue based on the data from our series and the literature. Materials and Methods Data from 49 patients diagnosed with non-metastatic bifocal germinoma at our hospital during the last 10 years were collected. The Pediatric Quality of Life Inventory 4.0 was used to evaluate health-related quality of life (HRQOL). Additionally, 81 patients identified from the literature were also analyzed independently. Results In our cohort, 34 patients had tumors in the sellar/suprasellar (S/SS) plus pineal gland (PG) regions and 15 in the S/SS plus basal ganglia/thalamus (BG/T) regions. The median follow-up period was 52 months (range, 10 to 134 months). Our survival analysis showed that patients treated with CSI (n=12) or whole-brain radiotherapy (WBRT; n=34) had comparable disease-free survival (DFS; p=0.540), but better DFS than those treated with focal radiotherapy (FR; n=3, p=0.016). All 81 patients from the literature had tumors in the S/SS+PG regions. Relapses were documented in 4/45 patients treated with FR, 2/17 treated with whole-ventricle irradiation, 0/4 treated with WBRT, and 1/15 treated with CSI. Survival analysis did not reveal DFS differences between the types of radiation field (p=0.785). HRQOL analysis (n=44) in our cohort found that, compared with S/SS+PG germinoma, patients with BG/T involvement had significantly lower scores in social and school domains. However, HRQOL difference between patients treated with CSI and those not treated with CSI was not significant. Conclusion In patients with non-metastatic bifocal germinoma, it is rational that CSI could be replaced by limited-field radiation. HRQOL in patients with BG/T involvement was poorer.

An Improved Haze Removal Algorithm Based on Genetic Fuzzy Clustering

Xiaoguang Li,Huiying Huang 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.8

Aiming at the degeneration phenomenon of images taken in mist, according to the features of the degraded images, an improved haze removal algorithm based on genetic fuzzy clustering is presented in this paper after analyzing its defects and shortcomings. Firstly, the improved atmospheric scattering model is established. Secondly, the original image is converted into a standard image through the improved model, and then we present a new multi-scale image edge detection by genetic fuzzy clustering, Based on this observation, we can use the multi-scale image edge detection to estimate the haze thickness directly and recover a high quality haze-free image. The new algorithm uses good global search ability of the genetic algorithm, which will implement the transfer from the scene defogging problem into the optimal estimation problem under global contrast optimal point. Compared with other algorithms for degraded images, the improved haze removal algorithm not only detects image edge precisely, but also has better performance in situations of dense haze. Theoretical analysis and experimental results demonstrate that, the new algorithm improved in this paper are effective for removal of fog-degraded images, and can be applied to the practical situations.

Exoproduction and Biochemical Characterization of a Novel Serine Protease from Ornithinibacillus caprae L9^T with Hide-Dehairing Activity

( Xiaoguang Li ),( Qian Zhang ),( Longzhan Gan ),( Guangyang Jiang ),( Yongqiang Tian ),( Bi Shi ) 한국미생물 · 생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.1

This study is the first report on production and characterization of the enzyme from an Ornithinibacillus species. A 4.2-fold increase in the extracellular protease (called L9^T) production from Ornithinibacillus caprae L9^T was achieved through the one-factor-at-a-time approach and response surface methodological optimization. L9T protease exhibited a unique protein band with a mass of 25.9 kDa upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This novel protease was active over a range of pH (4-13), temperatures (30-80℃) and salt concentrations (0-220 g/l), with the maximal activity observed at pH 7, 70℃ and 20 g/l NaCl. Proteolytic activity was upgraded in the presence of Ag⁺, Ca²⁺ and Sr²⁺, but was totally suppressed by 5 mM phenylmethylsulfonyl fluoride, which suggests that this enzyme belongs to the serine protease family. L9^T protease was resistant to certain common organic solvents and surfactants; particularly, 5 mM Tween 20 and Tween 80 improved the activity by 63 and 15%, respectively. More importantly, L9^T protease was found to be effective in dehairing of goatskins, cowhides and rabbit-skins without damaging the collagen fibers. These properties confirm the feasibility of L9^T protease in industrial applications, especially in leather processing.

Seismic Rotational Stability Analysis of Gravity Retaining Wall under Heavy Rainfall

Xiaoguang Li,Jie Liu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.12

A new methodology for the rotational stability analysis of a gravity retaining wall supporting inclined backfill under earthquake and heavy rainfall conditions has been presented.According to the movement mode of retaining wall and the characteristics of backfill sliding and rainwater infiltration, a sliding model of the infinite soil strip and rainwater infiltration model were established respectively. By calculating the internal energy dissipation rate and external loads power of the wall-soil system mechanism, a formula to calculate seismic yield acceleration coefficient under coupling conditions of earthquakes and rainfall was deduced.The results revealed a large effect size of infiltration depth of rainwater and the backfill inclination on the seismic yield acceleration coefficient. When the rainwater reaches 1/5 the height of the retaining wall and the backfill inclination exceeds 15°, the seismic yield acceleration coefficient will decrease rapidly. Moreover, the results obtained in this paper showed good consistency with those obtained by numerical simulation.

Research on Improved Fuzzy Optimization Routing Problem in WSNs Based on Genetic Ant Colony Algorithm

Xiaoguang Li,Guanghong Li,Songan Zhang,Qiang Yuan 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.5

The combination of traditional ant colony algorithm in solving the optimization process to consume a large amount of time, easily falling into local optimal solution and convergence is slow and other disadvantages, while also generating a lot of useless redundant iterative code, operation efficiency is low. Therefore, ant colony optimization algorithm is proposed. The algorithm based on genetic algorithm has the ability to search the global ant colony algorithm also has a parallel and positive feedback mechanisms. Changes in the use of genetic algorithm selection operator, crossover operator and mutation operator action to determine the distribution of pheromone on the path, the ant colony algorithm for feature selection using support vector machine classifiers for evaluating the performance characteristics of the feedback sub-Variorum And by changing the pheromone iteration, parameter selection and increase the local pheromone update feature nodes guided the re-combination. The algorithm uses probability expectation values are obtained to meet under the conditions with minimal sensor nodes, and gives the optimal coverage and connectivity probability models and reasoning. The experimental results show that, the algorithm can not only use the least nodes complete the effective target area to be covered, and in reducing the network energy consumption is also greatly improved, simultaneously reduces the cyber source configuration, improve the network life cycle.

Study on Improved Algorithm for Image Edge Detection Based on Genetic Fuzzy

Xiaoguang Li,Bianxia Wu,Yuanbo Li 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.7

Aiming at the existing edge detection algorithm of edge vague, the pseudo-edge cannot be removed and algorithm results do not achieve optimal results by virtue. In order to improve the reliability and effectiveness of edge detection, the proposed optimization tool template coefficient method, to design the coding, Sobel filter and fitness function of genetic fuzzy clustering algorithm. Through interpolating, smooth handling and filtering with the updated active contour model. Based on the traditional edge detection algorithm is analyzed, combined with fuzzy membership functions and genetic operators for edge detection algorithm was improved by genetic fuzzy clustering. Through the simulation results showed that this new algorithm was feasible. Theoretical analysis and experimental results demonstrate that, the new algorithm in this paper is highly antinoise and able to get better image edges.

Eu³⁺→Eu²⁺ unusual reduction and bond energy in MAlSi₂O₆:Eu (M = Li, Na, K, Rb, Cs)

Pan, Yu,Wang, Wenjun,Zhu, Yuhan,Xu, Haibing,Noh, Hyeon Mi,Jeong, Jung Hyun,Liu, Xiaoguang,Li, Ling Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.7

<P><B>Abstract</B></P> <P>Eu-doped MAlSi<SUB>2</SUB>O<SUB>6</SUB> (M = Li, Na, K, Rb, Cs) phosphors were synthesized by solid-state reaction in air. The crystal structure and optical properties of the phosphors were investigated by X-ray powder diffraction and photoluminescence. Their emission spectra are composed of some broad bands coming from the 5d-4f transition of Eu<SUP>2+</SUP> and some sharp emission peaks coming from the f-f transitions of Eu<SUP>3+</SUP>. The co-existence of Eu<SUP>3+</SUP> and Eu<SUP>2+</SUP> cations is detected in MAlSi<SUB>2</SUB>O<SUB>6</SUB>:2%Eu, which shows that the unusual Eu<SUP>3+</SUP>→Eu<SUP>2+</SUP> reduction process occurs in MAlSi<SUB>2</SUB>O<SUB>6</SUB>. The preferential occupancy of Eu<SUP>3+</SUP> or Eu<SUP>2+</SUP> in MAlSi<SUB>2</SUB>O<SUB>6</SUB> can be calculated to be M<SUP>+</SUP> sites by the bond-energy method. The deviation of the Eu<SUP>3+</SUP>–O<SUP>2-</SUP> bond energy is closed to that of the Eu<SUP>2+</SUP>–O<SUP>2-</SUP> bond energy, which means that Eu<SUP>3+</SUP> and Eu<SUP>2+</SUP> can coexist in air. The abnormal reduction of Eu<SUP>3+</SUP> to Eu<SUP>2+</SUP> can be explained by charge compensation model. The doped Eu<SUP>3+</SUP> was induced to M<SUP>+</SUP> and the vacancy (<I>V</I> <SUB> <I>M</I> </SUB>) may be formed. The vacancy(<I>V</I> <SUB> <I>M</I> </SUB>) acted as a donor of electrons, and the Eu M ∙ ∙ defect acted as an acceptor of electrons. The theoretical result is consistent with the experimental phenomenon.</P>

Relationships among bedding materials, bedding bacterial composition and lameness in dairy cows

Li, Han,Wang, Xiangming,Wu, Yan,Zhang, Dingran,Xu, Hongyang,Xu, Hongrun,Xing, Xiaoguang,Qi, Zhili Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.9

Objective: Bedding materials directly contact hooves of dairy cows and they may serve as environmental sources of lameness-associated pathogen. However, the specific composition of bacteria hidden in bedding materials is still not clear. The aim of this study was to determine the effect bedding material and its bacterial composition has on lameness of Holstein heifers. Methods: Forty-eight Holstein heifers with similar body weights were randomly assigned into three groups including sand bedding (SB), concrete floor (CF), and compost bedding (CB). Hock injuries severity and gait performance of dairy cows were scored individually once a week. Blood samples were collected at the end of the experiment and bedding material samples were collected once a week for Illumina sequencing. Results: The CF increased visible hock injuries severity and serum biomarkers of joint damage in comparison to SB and CB groups. Besides, Illumina sequencing and analysis showed that the bacterial community of CB samples had higher similarity to that of SB samples than CF samples. Bacteria in three bedding materials were dominated by gastrointestinal bacteria and organic matter-degrading bacteria, such as Actinobacteria, Firmicutes, and norank JG30-KF-cM45. Lameness-associated Spirochaetaceae and Treponeme were only detected in SB and CB samples with a very low relative abundance (0% to 0.08%). Conclusion: The bacterial communities differed among bedding materials. However, the treponemes pathogens involved in the pathogenesis of lameness may not be a part of microbiota in bedding materials of dairy cows.