Microstructure design and energy transfer in Gd2(WO4)3: Yb3+/Er3+ phosphors

Wang Yunfeng,Chen Jun,Wei Xiaoyu,Cui Shaobo,Jia Xiao 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.78 No.9

Rare-earth-doped upconverison luminescent (UCL) materials have wide application prospects in the feld of nanoptoelectronics technology. However, achieving highly efficient UCL materials is still a big challenge due to the serious nonradiative energy loss in the host materials. In this research, Gd2(WO4)3: Yb3+, Er3+ inverse opal photonic crystals (IOPCs) were prepared using a polymethylmethacrylate (PMMA) template-assisted method, and the efects of modulations of the IOPC structure on UC emission properties of Er3+ were investigated systemically. As a result, the emission intensity of 2 H11/2- 4 I15/2 in IOPC was found to be suppressed 37.4%, and the radiative lifetimes of 4 S3/2- 4 I15/2 were prolonged 1.55 times. The effects of the doping concentration on the reciprocal of fluorescence lifetimes of 4 S3/2- 4 I15/2 between the IOPC and the reference (REF) samples showed that the cross-energy transfer (CET) rate and the electronic transition rate were greatly inhibited, which could be due to the effect of the modulation of the effective index on the radiative transition rate and on the decrease of nonradiative transition rate caused by periodic thin-walled structure of IOPC. The power-dependent UC emission properties validated the supposition that the IOPC structure could be effectively suppressed the local thermal effect and thermal quenching. This research presents a further step in the exploration of the new kind of UCL materials with high luminous efficiency.

IL-33 Promotes ST2-Dependent Fibroblast Maturation via P38 and TGF-β in a Mouse Model of Epidural Fibrosis

Wang Haoran,Wu Tao,Hua Feng,Sun Jinpeng,Bai Yunfeng,Wang Weishun,Liu Jun,Zhang Mingshun 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.3

BACKGROUND: Recent evidence suggests that IL-33, a novel member of the IL-1b family, is involved in organ fibrosis. However, the roles of IL-33 and its receptor ST2 in epidural fibrosis post spine operation remain elusive. METHODS: A mouse model of epidural fibrosis was established after laminectomy. IL-33 in the wound tissues post laminectomy was measured with Western blotting, ELISA and immunoflurosence imaging. The fibroblast cell line NIH- 3T3 and primary fibroblasts were treated with IL-33 and the mechanisms of maturation of fibroblasts into myofibroblasts were analyzed. To explore roles of IL-33 and its receptor ST2 in vivo, IL-33 knockout (KO) and ST2 KO mice were employed to construct the model of laminectomy. The epidural fibrosis was evaluated using H&E and Masson staining, western-blotting, ELISA and immunohistochemistry. RESULTS: As demonstrated in western blotting and ELISA, IL-33 was increased in epidural wound tissues post laminectomy. The immunoflurosence imaging revealed that endothelial cells (CD31?) and fibroblasts (a-SAM?) were major producers of IL-33 in the epidural wound tissues. In vitro, IL-33 promoted fibroblast maturation, which was blocked by ST2 neutralization antibody, suggesting that IL-33-promoted-fibroblasts maturation was ST2 dependent. Further, IL-33/ ST2 activated MAPK p38 and TGF-b pathways. Either p38 inhibitor or TGF-b inhibitor decreased fibronectin and a-SAM production from IL-33-treated fibroblasts, suggesting that p38 and TGF-b were involved with IL-33/ST2 signal pathways in the fibroblasts maturation. In vivo, IL-33 KO or ST2 KO decreased fibronectin, a-SMA and collagen deposition in the wound tissues of mice that underwent spine surgery. In addition, TGF-b1 was decreased in IL-33 KO or ST2 KO epidural wound tissues. CONCLUSION: In summary, IL-33/ST2 promoted fibroblast differentiation into myofibroblasts via MAPK p38 and TGFb in a mouse model of epidural fibrosis after laminectomy.

A New MAC Protocol PB-TDMA for WSNs Based on Event-driven

Hui Wang,Xuefeng Li,Yunfeng Wang 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.11

In order to improve the WSN, a novel WSN protocol based on the event-driven named PB-TDMA is proposed. One of the problems in the WSN protocol is that each node’s probability of data delivery is usually diverse at different time and environment. This paper puts forward a method to resolve such a problem. It makes two nodes with different probability share a time slot which could use to compress the frame length and enhance the utilization ratio of channel. In addition, through running statistics on the probability of each node’s data sending, it proposes a new allocation method of time slot to avoid data collision. On the basis of the above strategy, we can constantly update the delivery rate to achieve the goal of adaptive. Simulation results show that PB-TDMA protocol performs better for wireless sensor network with high-density deployment and moderate load.

Diterpenoids from Leonurus japonicus

Wu, Hankui,Wang, Sensheng,Liu, Haijuan,Yan, E.,Wang, Jinjin,Wang, Xiangbei,Wei, Wenchao,Xu, Zhiyong,Sun, Shanshan,Li, Yan,Liu, Ruijin,Li, Gang,Shi, Yunfeng Korean Chemical Society 2015 대한화학회지 Vol.59 No.2

In vivo study of microarc oxidation coated Mg stent to heal bone trauma defect

Yunfeng Wu,Yaming Wang,Nan Zhang,Jinpeng Zhuang,Jinglong Yan,Daqing Wei,Baoqiang Li,Dechang Jiaa,Yu Zhou 한국표면공학회 2017 한국표면공학회 학술발표회 초록집 Vol.2017 No.11

Explainable radionuclide identification algorithm based on the convolutional neural network and class activation mapping

Wang Yu,Yao Qingxu,Zhang Quanhu,Zhang He,Lu Yunfeng,Fan Qimeng,Jiang Nan,Yu Wangtao 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.12

Radionuclide identification is an important part of the nuclear material identification system. The development of artificial intelligence and machine learning has made nuclide identification rapid and automatic. However, many methods directly use existing deep learning models to analyze the gammaray spectrum, which lacks interpretability for researchers. This study proposes an explainable radionuclide identification algorithm based on the convolutional neural network and class activation mapping. This method shows the area of interest of the neural network on the gamma-ray spectrum by generating a class activation map. We analyzed the class activation map of the gamma-ray spectrum of different types, different gross counts, and different signal-to-noise ratios. The results show that the convolutional neural network attempted to learn the relationship between the input gamma-ray spectrum and the nuclide type, and could identify the nuclide based on the photoelectric peak and Compton edge. Furthermore, the results explain why the neural network could identify gamma-ray spectra with low counts and low signal-to-noise ratios. Thus, the findings improve researchers’ confidence in the ability of neural networks to identify nuclides and promote the application of artificial intelligence methods in the field of nuclide identification.

Remediation of As/Cr co-contaminated soil by electrokinetic coupled with permeable reactive barrier

Yunfeng Xu,Yangfan Fang,Kaili Wang,Wei Xia,Guangren Qian 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.3

In this study, the permeable-reactive-barrier (PRB) assisted electrokinetic (EK) was used to remediate As/Cr Co-contaminated soil, aiming to explore the optimal remediation conditions and the migration of As/Cr. The effects of PRB active substance, PRB location, voltage gradient and running time on the migration and transformation of Cr and As in simulated As/Cr contaminated kaolin were studied. The optimal parameters were as follows: PRB position was located near the anode (PRB A, the medium of PRB was hydrocalumite (CaAl-LDH)), initial voltage gradient was 1 V/cm, running time was 96 h. Under the optimal conditions, the removal efficiency of total arsenic (TAs) and total chromium (TCr) were 40.1% and 81.0%, respectively. This indicated that EK can effectively migrate As and Cr, and PRB can effectively adsorb As and Cr. The migration of As tends to both anode and cathode, while Cr tends to migrate towards the anode. The XRD patterns and FTIR spectra confirmed that the As immobilized by CaAl-LDH was mainly adsorbed on the surface, while Cr existed in CaAl-LDH by surface adsorption and intercalation.

A Double-channel Four-band True Color Night Vision System

Yunfeng Jiang,Dongsheng Wu,Jie Liu,Kuo Tian,Dan Wang 한국광학회 2022 Current Optics and Photonics Vol.6 No.6

By analyzing the signal-to-noise ratio (SNR) theory of the conventional true color night vision system, we found that the output image SNR is limited by the wavelength range of the system response λ 1and λ 2 . Therefore, we built a double-channel four-band true color night vision system to expand the system response to improve the output image SNR. In the meantime, we proposed an image fusion method based on principal component analysis (PCA) and nonsubsampled shearlet transform (NSST) to obtain the true color night vision images. Through experiments, a method based on edge extraction of the targets and spatial dimension decorrelation was proposed to calculate the SNR of the obtained images and we calculated the correlation coefficient (CC) between the edge graphs of obtained and reference images. The results showed that the SNR of the images of four scenes obtained by our system were 125.0%, 145.8%, 86.0% and 51.8% higher, respectively, than that of the conventional tri-band system and CC was also higher, which demonstrated that our system can get true color images with better quality.

Characteristics of isolated lactic acid bacteria and their effects on the silage quality

Siran Wang,Xianjun Yuan,Zhihao Dong,Junfeng Li,Gang Guo,Yunfeng Bai,Junyu Zhang,Tao Shao 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.6

Objective: Four lactic acid bacteria (LAB) strains isolated from common vetch, tall fescue and perennial ryegrass on the Tibetan Plateau were characterized, and their effects on the fermentation quality of Italian ryegrass (Lolium multiflorum Lam.) silage were studied. Methods: The four isolated strains and one commercial inoculant (G, Lactobacillus plantarum MTD-1) were evaluated using the acid production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. The five LAB strains were added to Italian ryegrass for ensiling at three different temperatures (10°C, 15°C, and 25°C). Results: All isolated strains (LCG3, LTG7, I5, and LI3) could grow at 5°C to 20°C, pH 3.0 to 8.0 and NaCl (3.0%, 6.5%). Strains LCG3, LTG7, I5, and LI3 were identified as Lactobacillus plantarum, Pediococcus acidilactici, Lactobacillus paraplantarum, and Lactobacillus casei by sequencing 16S rDNA, respectively. All LAB inoculants significantly (p<0.05) increased lactic acid (LA) contents and ratios of lactic acid to acetic acid, and reduced pH and ammonia nitrogen/ total nitrogen (AN/TN) compared with uninoculated silages at various temperatures (10°C, 15°C, and 25°C). Compared to the commercial inoculant G, I5, and LI3 showed similar effects on improving the silage quality of Italian ryegrass at 10°C and 15°C, indicated by similar pH, LA content and AN/TN. Conclusion: All inoculants could improve the silage fermentation quality at various temperatures (10°C, 15°C, and 25°C). At the temperature of 10°C and 15°C, strain I5 and LI3 had similar effects with the commercial inoculant G on improving the silage quality of Italian ryegrass.

Analysis of Meteorological Disasters and Its Impact based on Production Function

Chen Yunfeng,Li Lianshui,Cui Mengmeng,Wang Jin 보안공학연구지원센터 2012 International Journal of Hybrid Information Techno Vol.5 No.2