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Advances in High Emission Sc<sub>2</sub>O<sub>3</sub>-W Matrix Cathode Materials
Wang, Jinshu,Yang, Yunfei,Liu, Wei,Wang, Yiman Korean Society of Microscopy 2016 Applied microscopy Vol.46 No.1
Our work on $Sc_2O_3-W$ matrix dispenser cathodes had been reviewed in this paper. The cathode with uniform distribution of $Sc_2O_3$ had been obtained using liquid-liquid doping method. The cathode had excellent emission property, i.e., the emission current density in pulse condition could reach over $35A/cm^2$. It was found that the cathode surface was covered by a Ba-Sc-O active substance multilayer with a thickness of about 100 nm, which was different from the monolayer and semiconducting layer in thickness. Furthermore, the observation results displayed that nanoparticles appeared at the growth steps and the surface of tungsten grains of the fully activated cathode. The calculation result indicated that the nanoparticles could cause the increase of local electric field strengths. We proposed the emission model that both the Ba-Sc-O multilayer and the nanoparticles distributing mainly on the growth steps of the W grains contributed to the emission. The future work on this cathode has been discussed.
Yunfei Dai,Wei Ma,Tong Zhang,Jinwei Yang,Chenghao Zang,Kuangpin Liu,Xianbin Wang,Jiawei Wang,Zhen Wu,Xingkui Zhang,Chunyan Li,Junjun Li,Xiangpeng Wang,Jianhui Guo,Liyan Li 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.3
Long noncoding RNAs (lncRNAs) play important roles in the process of cell fate determination. However, their function and expression profiles have not yet been systematically investigated during the transdifferentiation of glial precursor cells derived from dorsal root ganglia (DRG) in the peripheral nervous system. Our results demonstrated significant differences in gene architecture and expression among the three transcript types (lncRNA, mRNA, and TUCP). Distinct differences in transcript length, exon number, and ORF length were identified between lncRNAs and mRNAs after comparative analysis of their structure and sequence conservation. We found that the upregulated lncRNAs outnumbered the downregulated lncRNAs in glial precursor cells cultured with proBDNF antiserum compared with the levels in glial precursor cells cultured without proBDNF antiserum. By a series of GO and KEGG analyses, we found that the effects of some lncRNAs on their target genes in cis were related to nerve growth factor-induced cell cycle, cell phenotype change, and neuronal differentiation. The qRT-PCR verification results of lncRNAs ENSRNOT00000091991, ENSRNOT00000087717, and LNC_000429 were mostly consistent with the sequencing results. The candidate lncRNAs may be associated with the neuronal transdifferentiation of glial precursor cells. Our study provides the first evidence for a remarkably diverse pattern of lncRNA expression during neuronal differentiation of glial precursor cells from rat DRG, and also provides a resource for lncRNA studies in the field of cell differentiation.
Yunfei Chen,Qian Shen,Yueyue Wang,Tao Wang,Shaoyan Wu,Ling Zhang,Xu Lu,Fangyuan Zhang,Weimin Jiang,Bo Qiu,Erdi Gao,Xiaofen Sun,Kexuan Tang 한국식물생명공학회 2013 Plant biotechnology reports Vol.7 No.3
Artemisinin is an endoperoxide sesquiterpenelactone isolated from the aerial parts of Artemisia annua L.,and is presently the most potent anti-malarial drug. Owingto the low yield of artemisinin from A. annua as well as thewidespread application of artemisinin-based combinationtherapy recommended by the World Health Organization,the global demand for artemisinin is substantially increasingand is therefore rendering artemisinin in short supply. An economical way to increase artemisinin production is toincrease the content of artemisinin in A. annua. In thisstudy, three key genes in the artemisinin biosynthesispathway, encoding farnesyl diphosphate synthase, amorpha-4, 11-diene C-12 oxidase and its redox partner cytochromeP450 reductase, were over-expressed in A. annuathrough Agrobacterium-mediated transformation. Thetransgenic lines were confirmed by Southern blotting andthe over-expressions of the genes were demonstrated byreal-time PCR assays. The HPLC analysis showed that theartemisinin contents in transgenic lines were increasedsignificantly, with the highest one found to be 3.6-foldhigher (2.9 mg/g FW) than that of the control. Theseresults demonstrate that multigene engineering is aneffective way to enhance artemisinin content in A. annua.
Wang, Yunfei,Ricard, Andre,Sarrette, Jean-Philippe,Kim, Ansoon,Kim, Yu Kwon Elsevier Sequoia 2017 Surface & coatings technology Vol.324 No.-
<P><B>Abstract</B></P> <P>We find that surface modification characteristics of TiO<SUB>2</SUB> using N<SUB>2</SUB> RF plasma are strongly dependent on the detailed composition of active species in the plasma and the afterglows. The surface nitriding of ALD-grown TiO<SUB>2</SUB> films in pure N<SUB>2</SUB> RF afterglows at room temperature (RT) is found to be more effective in the late afterglows than in the early afterglows. Adding a small fraction of H<SUB>2</SUB> in N<SUB>2</SUB> results in suppression of surface nitriding, suggesting that the change in the composition of the active species in the afterglows by H<SUB>2</SUB> is the origin to the suppressed nitriding performance. Here, we present our analysis on the surface chemical composition after the plasma modification as well as the densities of excited species such as N atoms, N<SUB>2</SUB>(A) and N<SUB>2</SUB>(X, <I>v</I>) metastable molecules and N<SUB>2</SUB> <SUP>+</SUP> ions in the afterglows of RF N<SUB>2</SUB> and N<SUB>2</SUB>–H<SUB>2</SUB> (<5%) at different positions along the downstream by emission spectroscopy. The early afterglow of N<SUB>2</SUB> changes from a pink to a late afterglow where the N+N recombination is the dominant process with the introduction of H<SUB>2</SUB>. The roles of active species such as N–atoms and N<SUB>2</SUB> <SUP>+</SUP> ions on TiO<SUB>2</SUB> surface nitriding are found to oppose to each other. We find that N atoms enhance the surface nitriding, while N<SUB>2</SUB> <SUP>+</SUP> ions are likely to deplete the surface-bound N species.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Surface nitriding of TiO<SUB>2</SUB> in the N<SUB>2</SUB> RF afterglow at RT is strongly dependent on the active species densities. </LI> <LI> High density of neutral N atoms plays a beneficial role in the surface nitriding of TiO<SUB>2</SUB>. </LI> <LI> The vibrationally excited N<SUB>2</SUB> and N<SUB>2</SUB> <SUP>+</SUP> species play a negative role in the surface nitriding performance. </LI> </UL> </P>
A new fault diagnosis method based on convolutional neural network and compressive sensing
Yunfei Ma,Xisheng Jia,Huajun Bai,Guozeng Liu,Guanglong Wang,Chiming Guo,Shuangchuan Wang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11
Compressive sensing is an efficient machinery monitoring framework, which just needs to sample and store a small amount of observed signal. However, traditional reconstruction and fault detection methods cost great time and the accuracy is not satisfied. For this problem, a 1D convolutional neural network (CNN) is adopted here for fault diagnosis using the compressed signal. CNN replaces the reconstruction and fault detection processes and greatly improves the performance. Since the main information has been reserved in the compressed signal, the CNN is able to extract features from it automatically. The experiments on compressed gearbox signal demonstrated that CNN not only achieves better accuracy but also costs less time. The influencing factors of CNN have been discussed, and we compared the CNN with other classifiers. Moreover, the CNN model was also tested on bearing dataset from Case Western Reserve University. The proposed model achieves more than 90 % accuracy even for 50 % compressed signal.
A Novel Redundant Data Storage Algorithm Based on Minimum Spanning Tree and Quasi-randomized Matrix
( Jun Wang ),( Qiong Yi ),( Yunfei Chen ),( Yue Wang ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.1
For intermittently connected wireless sensor networks deployed in hash environments, sensor nodes may fail due to internal or external reasons at any time. In the process of data collection and recovery, we need to speed up as much as possible so that all the sensory data can be restored by accessing as few survivors as possible. In this paper a novel redundant data storage algorithm based on minimum spanning tree and quasi-randomized matrix―QRNCDS is proposed. QRNCDS disseminates k source data packets to n sensor nodes in the network (n>k) according to the minimum spanning tree traversal mechanism. Every node stores only one encoded data packet in its storage which is the XOR result of the received source data packets in accordance with the quasi-randomized matrix theory. The algorithm adopts the minimum spanning tree traversal rule to reduce the complexity of the traversal message of the source packets. In order to solve the problem that some source packets cannot be restored if the random matrix is not full column rank, the semi-randomized network coding method is used in QRNCDS. Each source node only needs to store its own source data packet, and the storage nodes choose to receive or not. In the decoding phase, Gaussian Elimination and Belief Propagation are combined to improve the probability and efficiency of data decoding. As a result, part of the source data can be recovered in the case of semi-random matrix without full column rank. The simulation results show that QRNCDS has lower energy consumption, higher data collection efficiency, higher decoding efficiency, smaller data storage redundancy and larger network fault tolerance.
DETECTION AND RESTORATION OF NON-RADIAL VARIATION OVER FULL-DISK SOLAR IMAGES
Yunfei Yang,Jiaben Lin,Song Feng,Hui Deng,Feng Wang,Kai-fan Ji 한국천문학회 2013 Journal of The Korean Astronomical Society Vol.46 No.5
Full-disk solar images are provided by many solar telescopes around the world. However, the observed images show Non-Radial Variation (NRV) over the disk. In this paper, we propose algorithms for detecting distortions and restoring these images. For detecting NRV, the cross-correlation coefficients matrix of radial profiles is calculated and the minimum value in the matrix is defined as the Index of Non-radial Variation (INV). This index has been utilized to evaluate the H$\alpha$ images of GONG, and systemic variations of different instruments are obtained. For obtaining the NRV's image, a Multi-level Morphological Filter (MMF) is designed to eliminate structures produced by solar activities over the solar surface. Comparing with the median filter, the proposed filter is a better choice. The experimental results show that the effect of our automatic detection and restoration methods is significant for getting a flat and high contrast full-disk image. For investigating the effect of our method on solar features, structural similarity (SSIM) index is utilized. The high SSIM indices (close to 1) of solar features show that the details of the structures remain after NRV restoring.