Growth of lead-based functional crystals by the vertical bridgman method

Xu Jiayue The Korea Association of Crystal Growth 2006 韓國結晶成長學會誌 Vol.16 No.1

Some lead-based crystals show excellent ferroelectric, piezoelectric or scintillation properties and have attracted much attention in recent years. However, the erosion of the high temperature solution on platinum crucible and the evaporation of PbO component are the main problems often encountered during the crystal growth. In this paper, we reported recent progress on the Bridgman growth of lead-based functional crystals, such as novel relaxor ferroelectric crystals (PZNT and PMNT), scintillation crystals $(PbWO_4,\;PbF_2\;and\;PbClF)$ and piezoelectric crystals $(Pb_5Ge_3O_{11}\;and\;Pb_2KNb_5O_{15}),$ in Shanghai Institute of Ceramics, Chinese Academy of Sciences. The vertical Bridgman method has been modified to grow PZNT crystals from high temperature solution and as-grown crystals have been characterized. Large size lead-based scintillators, $PbWO_4\;and\;PbF_2$ crystals, have been mass-produced by the vertical Bridgman method in the multi-crucible fumace. These crystals have been supplied to CERN and other laboratories for high-energy physics experiments. The Bridgman growth of piezoelectric crystals $Pb_5Ge_3O_{11}\;and\;Pb_2KNb_5O_{15}$ are discussed also.

Comparison of Atmospheric Vertical Motion over China in ERA-Interim, JRA-55, and NCEP/NCAR Reanalysis Datasets

Jiayu Xu,Rongxiang Tian,Song Feng 한국기상학회 2021 Asia-Pacific Journal of Atmospheric Sciences Vol.57 No.4

Vertical motion is an important feature of the atmosphere, being closely linked to clouds and precipitation. Here, we present a comparison of the vertical velocity of air over China, with particular focus on the Tibetan Plateau, during the period 1981–2010 using three reanalysis datasets: ERA-Interim, JRA-55 and NCEP/NCAR. Analysis methods including empirical orthogonal functions analysis and correlation analysis were used to examine consistency between the datasets and their suitability in research and application in China. Our results show that the vertical velocity fields from ERA-Interim and JRA-55 are more consistent than they are with those from NCEP/NCAR. The atmospheric vertical velocity fields from NCEP/NCAR lack details compared with those obtained from ERA-Interim and JRA-55, and part of values for the upper troposphere over the ocean south of 15°N are contrary to the other datasets and the climatic reality. Therefore, use of ERA-Interim or JRA-55 may be preferable over NCEP/NCAR. The intensity of atmospheric vertical motion in the lower troposphere in JRA-55 is significantly higher than in ERA-Interim and NCEP/NCAR. In summer, the JRA-55 data are closest to the observed wind fields and the data stability best for the Tibetan Plateau region. Our results provide guidance for better application of reanalysis data and more accurate climate prediction for this region.

Enhanced mechanical properties and interface structure characterization of W-La₂O₃ alloy designed by an innovative combustion-based approach

Chen, Pengqi,Xu, Xian,Wei, Bangzheng,Chen, Jiayu,Qin, Yongqiang,Cheng, Jigui Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.5

Oxide dispersion strengthening (ODS) tungsten alloys are highly desirable in irradiation applications. However, how to improve the properties of ODS-tungsten alloys efficiently has been worth studying for a long time. Here we report a nanostructuring approach that achieves W-La₂O₃ alloy with a high level of flexural strength and Vickers hardness at room temperature, which have the maximum value of 581 MPa and 703 Hv, respectively. This method named solution combustion synthesis (SCS) can generate 30 nm coating structures W-La₂O₃ composite powders by using Keggin-type structural polyoxometalates as raw materials in a fast and low-cost process. The composite powder can be fabricated to W-La₂O₃ alloy with an optimal microstructure of submicrometric W grains coexisting with nanometric oxide particles in the grain interior, and a stability interface structure of grain boundaries (GBs) by forming transition zones. The method can be used to prepare new ODS alloys with excellent properties in the future.

Single-cell transcriptomic analysis reveals transcriptional and cell subpopulation differences between human and pig immune cells

Li Jie,Xu Yanan,Zhang Jiayu,Zhang Zhaoqi,Guo Han,Wei Dong,Wu Changhong,Hai Tang,Sun Hai-Xi,Zhao Yong 한국유전학회 2024 Genes & Genomics Vol.46 No.3

Background The pig is a promising donor candidate for xenotransplantation. Understanding the differences between human and swine immune systems is critical for addressing xenotransplant rejection and hematopoietic reconstitution. The gene transcriptional profile differences between human and pig immune cell subpopulations have not been studied. To assess the similarities and differences between pigs and humans at the levels of gene transcriptional profiles or cell subpopulations are important for better understanding the cross-species similarity of humans and pigs, and it would help establish the fundamental principles necessary to genetically engineer donor pigs and improve xenotransplantation. Objective To assess the gene transcriptional similarities and differences between pigs and humans. Methods Two pigs and two healthy humans’ PBMCs were sorted for 10 × genomics single-cell sequence. We generated integrated human-pig scRNA-seq data from human and pig PBMCs and defined the overall gene expression landscape of pig peripheral blood immune cell subpopulations by updating the set of human-porcine homologous genes. The subsets of immune cells were detected by flow cytometry. Results There were significantly less T cells, NK cells and monocytes but more B cells in pig peripheral blood than those in human peripheral blood. High oxidative phosphorylation, HIF-1, glycolysis, and lysosome-related gene expressions in pig CD14+ monocytes were observed, whereas pig CD14+ monocytes exhibited lower levels of cytokine receptors and JAK-STAT-related genes. Pig activated CD4+T cells decreased cell adhesion and inflammation, while enriched for migration and activation processes. Porcine GNLY+CD8+T cells reduced cytotoxicity and increased proliferation compared with human GNLY+CD8+T cells. Pig CD2+CD8+γδT cells were functionally homologous to human CD2+CD4+ γδT cells. Pig CD2−CD8−γδT cells expressed genes with quiescent and precursor characteristics, while CD2−CD8+γδT cells expressed migration and memory-related molecules. Pig CD24+ and CD5+B cells are associated with inflammatory responses. Conclusion Our research with integrated scRNA-seq assays identified the different distribution of pig immune cell subpopulations and the different transcriptional profiles of human and pig immune cells. This study enables a deeper understanding of the development and function of porcine immune cells. Background The pig is a promising donor candidate for xenotransplantation. Understanding the differences between human and swine immune systems is critical for addressing xenotransplant rejection and hematopoietic reconstitution. The gene transcriptional profile differences between human and pig immune cell subpopulations have not been studied. To assess the similarities and differences between pigs and humans at the levels of gene transcriptional profiles or cell subpopulations are important for better understanding the cross-species similarity of humans and pigs, and it would help establish the fundamental principles necessary to genetically engineer donor pigs and improve xenotransplantation. Objective To assess the gene transcriptional similarities and differences between pigs and humans. Methods Two pigs and two healthy humans’ PBMCs were sorted for 10 × genomics single-cell sequence. We generated integrated human-pig scRNA-seq data from human and pig PBMCs and defined the overall gene expression landscape of pig peripheral blood immune cell subpopulations by updating the set of human-porcine homologous genes. The subsets of immune cells were detected by flow cytometry. Results There were significantly less T cells, NK cells and monocytes but more B cells in pig peripheral blood than those in human peripheral blood. High oxidative phosphorylation, HIF-1, glycolysis, and lysosome-related gene expressions in pig CD14+ monocytes were observed, whereas pig CD14+ monocytes exhibited lower levels of cytokine receptors and JAK-STAT-related genes. Pig activated CD4+T cells decreased cell adhesion and inflammation, while enriched for migration and activation processes. Porcine GNLY+CD8+T cells reduced cytotoxicity and increased proliferation compared with human GNLY+CD8+T cells. Pig CD2+CD8+γδT cells were functionally homologous to human CD2+CD4+ γδT cells. Pig CD2−CD8−γδT cells expressed genes with quiescent and precursor characteristics, while CD2−CD8+γδT cells expressed migration and memory-related molecules. Pig CD24+ and CD5+B cells are associated with inflammatory responses. Conclusion Our research with integrated scRNA-seq assays identified the different distribution of pig immune cell subpopulations and the different transcriptional profiles of human and pig immune cells. This study enables a deeper understanding of the development and function of porcine immune cells.

대학생 읽기동기 측정도구 타당화 연구

이채리,김연하,Xu Jiayu,김수연 한국인간발달학회 2017 人間發達硏究 Vol.24 No.3

This study aimed to propose a reading motivation scale for Korean university students based on Adults' Reading Motivation Scale of Schutte and Malouff(2007). A total of 212 university students including 84 males and 128 females were surveyed online. Factors and items were reconstructed by exploratory factor analysis; validity and reliability of the scale were verified through Cronbach’s α and correlation analysis. In the process of exploratory analysis, 3 items from the original scale were excluded because of low factor loadings, and the 18 item were categorized into four dimensions. The four factors that emerged from the process were named ‘reading as part of life’, ‘reading to acquire information’, ‘reading for recognition’, and ‘reading for intellectual challenge’. The reliabilities of the new scale for Korean university students were sound. The reliability of 18 item was .872, and the reliabilities of four factors ranged from .633 to .860. The total scores and sub-factor scores of the new scale had positive associations with reading time per day of the participants. Furthermore, reading motivation scores assessed with the new scale were significantly correlated with scores measured by existing reading motivation items. These results indicate that the newly proposed 18 item scale with four dimensions is a sound instrument for measuring reading motivation of university students in Korea. This instrument can be utilized for diverse studies and programs related to reading by Korean university students.

Bridgman growth, luminescence and energy transfer studies of Tm3+ or/and Dy3+ co-doped Bi4Si3O12 crystal phosphor

Bobo Yang,Jiayue Xu,Jun Zou,Yan Zhang,Tian Tian,Yaoqing Chu,Meiling Wang 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.6

Tm3+, Dy3+ and Tm3+/Dy3+ co-doped bismuth silicate (Bi4Si3O12, BSO) crystals were successfully grown by the modified verticalBridgeman method. The crystals have about 80% transmittance in the range from 320 nm to 650 nm except several obviouscharacteristic absorption peaks corresponding to transitions of 4f electrons of Tm3+ and Dy3+. The luminescence properties forwhite light emitting diode (w-LED) were investigated. Energy transfer from the Bi3+ ions to the Tm3+ and Dy3+ ions in Tm3+or/and Dy3+ co-doped Bi4Si3O12 crystal has been established by photoluminescence investigation upon UV excitation. Whenexcited by a proper UV-light, Tm3+ doped BSO crystal shows blue emission band centered at 460 nm ascribed to Tm3+ (1D2→ 3F4), Dy3+ doped BSO crystal shows blue band at 480 nm (4F9/2→ 6H15/2), yellow band at 574 nm (4F9/2→ 6H13/2) and red bandat 662 nm (4F9/2→ 6H11/2) of Dy3+ ions. A white light with chromaticity coordinate of x = 0.3298, y = 0.2905 by excitation of357 nm is achieved from Tm3+/Dy3+ co-doped Bi4Si3O12 crystal. These results indicate that Tm3+/Dy3+ co-doped Bi4Si3O12 as awhite emitting crystal has a potential application in white-LED.

Corporate Social Responsibility and Unsecured Debt: Evidence from China

Xia CHEN,Zhe MA,Jiayu SHI,Bingyan TU,Songtao XU 한국유통과학회 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.11

This study aims to investigate whether Corporate Social Responsibility (CSR) performance can help companies gain more bank unsecured loans. Additionally, this study analyzes the moderating effect of firm size and industry characteristics. Data was collected through the case of companies listed on the Shanghai Stock Exchange or the Shenzhen Stock Exchange in China between 2009 and 2018 with 5373 firmyear observations. The results of multivariable regression analysis show that good CSR performance exhibits a strong positive impact on unsecured debt, including short-term, long-term, and total unsecured debt, which indicates that corporate with good CSR performance can borrow more unsecured debt. further research shows that this effect is more pronounced for small enterprises and firms operating in heavy-polluting industries. Additionally, research on the impact mechanism finds that good CSR performance can help mitigate information asymmetry between borrower and lender, reduce moral hazard of borrower, and obtain support from key stakeholders, and therefore reduces the risk of default. The findings of this study suggest that firms with good CSR performance exhibit a preference for unsecured debt, but decline to provide collateral for debt. Overall, we emphasize and illustrate the important role of corporate CSR in bank credit financing.

Enhanced thermoelectric performance of Cu3SbSe4 doped with alkali-ion (Na and K)

Yunchen Dou,Qiqi Zhu,Yong Du,Jiayue Xu,Di Li 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.2

The thermoelectric properties of alkali-ion-doped compounds Cu 3 Sb 1− x M x Se 4 (M = Na and K) prepared by mechanicalalloying and spark plasma sintering compaction, are investigated systematically between 300 K and 673 K. The increase inthe hole carrier concentration causes a reduction in the electrical resistivity in the whole temperature range and a rise in thepower factor at elevated temperature for alkali-ion-doped compounds as compared to pristine Cu 3 SbSe 4 . For example, themaximum power factors for Cu 3 Sb 1− x Na x Se 4 ( x = 0.02 and 0.03) and Cu 3 Sb 0.99 K 0.01 Se 4 at 673 K are all increased by around1.6 times compared to the un-doped sample. As a result, the peak ZT value reaches 0.52 and 0.71 at 673 K for Cu 3 Sb 1− x Na x Se 4( x = 0.02 and 0.03) and Cu 3 Sb 0.99 K 0.01 Se 4 , which is 27% and 73% larger than that (0.41) of the un-doped sample, respectively. In this work, K-doping is more eff ective in improving thermoelectric performance of Cu 3 SbSe 4 , due to its larger ionic radius,which can bring more lattice distortions and point defects to scatter phonons than Na-doping.

The Impact of Carrier Transport Confinement on the Energy Transfer Between InGaN/GaN Quantum‐Well Nanorods and Colloidal Nanocrystals

Jiang, Bin,Zhang, Chunfeng,Wang, Xiaoyong,Park, Min Joo,Kwak, Joon Seop,Xu, Jian,Zhang, Huichao,Zhang, Jiayu,Xue, Fei,Xiao, Min WILEY‐VCH Verlag 2012 Advanced Functional Materials Vol.22 No.15

<P><B>Abstract</B></P><P>The energy transfer (ET) between InGaN/GaN multiple‐quantum‐well (MQW) nanorods (NRs) and semiconductor nanocrystals (NCs) for efficient color conversion is studied. An exceptional contribution of carrier transport confinement to the ET mechanisms is observed in the proximal side‐wall coupling system, which consists of InGaN/GaN NRs and CdSe NCs. Under relatively low or high excitation, the ET rate shows different carrier‐density dependence, resulting from different electron‐hole configurations, i.e., bound excitons and free carriers. In the localized exciton regime, the ET rate decreases when increasing temperature from 20 K to 200 K. However, in the free‐carrier regime, the ET rate varies insignificantly in the same temperature range. The temperature dependence in this NR‐NC coupling system is different from that in the previously studied planar MQW‐NC coupling system. It is suggested that the carrier transport confinement in NRs is a major factor for these divergences. The highly efficient ET with efficiency up to 80% shows a promising potential of using such NR‐NC coupled structures for ET‐pumped, NC‐based, light‐emitting devices.</P>

Feasibility of Free-Breathing, Non-ECG-Gated, Black-Blood Cine Magnetic Resonance Images With Multitasking in Measuring Left Ventricular Function Indices

Peng Pengfei,Yue Xun,Tang Lu,Wu Xi,Deng Qiao,Wu Tao,Cai Lei,Liu Qi,Xu Jian,Huang Xiaoqi,Chen Yucheng,Diao Kaiyue,Sun Jiayu 대한영상의학회 2023 Korean Journal of Radiology Vol.24 No.12

Objective: To clinically validate the feasibility and accuracy of cine images acquired through the multitasking method, with no electrocardiogram gating and free-breathing, in measuring left ventricular (LV) function indices by comparing them with those acquired through the balanced steady-state free precession (bSSFP) method, with multiple breath-holds and electrocardiogram gating. Materials and Methods: Forty-three healthy volunteers (female:male, 30:13; mean age, 23.1 ± 2.3 years) and 36 patients requiring an assessment of LV function for various clinical indications (female:male, 22:14; 57.8 ± 11.3 years) were enrolled in this prospective study. Each participant underwent cardiac magnetic resonance imaging (MRI) using the multiple breath-hold bSSFP method and free-breathing multitasking method. LV function parameters were measured for both MRI methods. Image quality was assessed through subjective image quality scores (1 to 5) and calculation of the contrast-to-noise ratio (CNR) between the myocardium and blood pool. Differences between the two MRI methods were analyzed using the Bland–Altman plot, paired t-test, or Wilcoxon signed-rank test, as appropriate. Results: LV ejection fraction (LVEF) was not significantly different between the two MRI methods (P = 0.222 in healthy volunteers and P = 0.343 in patients). LV end-diastolic mass was slightly overestimated with multitasking in both healthy volunteers (multitasking vs. bSSFP, 60.5 ± 10.7 g vs. 58.0 ± 10.4 g, respectively; P < 0.001) and patients (69.4 ± 18.1 g vs. 66.8 ± 18.0 g, respectively; P = 0.003). Acceptable and comparable image quality was achieved for both MRI methods (multitasking vs. bSSFP, 4.5 ± 0.7 vs. 4.6 ± 0.6, respectively; P = 0.203). The CNR between the myocardium and blood pool showed no significant differences between the two MRI methods (18.89 ± 6.65 vs. 18.19 ± 5.83, respectively; P = 0.480). Conclusion: Multitasking-derived cine images obtained without electrocardiogram gating and breath-holding achieved similar image quality and accurate quantification of LVEF in healthy volunteers and patients.