The edge-balance index sets of power-cycle nested graph

Qingwen Zhang 장전수학회 2013 Advanced Studies in Contemporary Mathematics Vol.23 No.4

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The Controller Development of Multi-layer Parking Equipment Based on STM32

Zhang Yongde,Zhang Qinxiang,Jiang Jingang,Zhao Yanjiang,Qian Qingwen,Tang Dedong,Tian Daifu 보안공학연구지원센터 2014 International Journal of Smart Home Vol.8 No.1

Identification of pathways and genes associated with cerebral palsy

Qingwen Zhu,Yufei Ni,Jing Wang,Honggang Yin,Qin Zhang,Lingli Zhang,Wenjun Bian,Bo Liang,Lingyin Kong,Liming Xuan,Naru Lu 한국유전학회 2018 Genes & Genomics Vol.40 No.12

Cerebral palsy (CP) is a non-progressive neurological disease, of which susceptibility is linked to genetic and environmental risk factors. More and more studies have shown that CP might be caused by multiple genetic factors, similar to other neurodevelopmental disorders. Due to the high genetic heterogeneity of CP, we focused on investigating related molecular pathways. Ten children with CP were collected for whole-exome sequencing by next-generation sequencing (NGS) technology. Customized processes were used to identify potential pathogenic pathways and variants. Three pathways (axon guidance, transmission across chemical synapses, protein–protein interactions at synapses) with twenty-three genes were identified to be highly correlated with CP. This study showed that the three pathways associated with CP might be the molecular mechanism of pathogenesis. These findings could provide useful clues for developing pathway-based pharmacotherapies. Further studies are required to confirm potential roles for these pathways in the pathogenesis of CP.

Arrays of horizontal carbon nanotubes of controlled chirality grown using designed catalysts

Zhang, Shuchen,Kang, Lixing,Wang, Xiao,Tong, Lianming,Yang, Liangwei,Wang, Zequn,Qi, Kuo,Deng, Shibin,Li, Qingwen,Bai, Xuedong,Ding, Feng,Zhang, Jin Macmillan Publishers Limited, part of Springer Nat 2017 Nature Vol.543 No.7644

<P>The semiconductor industry is increasingly of the view that Moore's law-which predicts the biennial doubling of the number of transistors per microprocessor chip-is nearing its end(1). Consequently, the pursuit of alternative semiconducting materials for nanoelectronic devices, including single-walled carbon nanotubes (SWNTs), continues(2-4). Arrays of horizontal nanotubes are particularly appealing for technological applications because they optimize current output. However, the direct growth of horizontal SWNT arrays with controlled chirality, that would enable the arrays to be adapted for a wider range of applications and ensure the uniformity of the fabricated devices, has not yet been achieved. Here we show that horizontal SWNT arrays with predicted chirality can be grown from the surfaces of solid carbide catalysts by controlling the symmetries of the active catalyst surface. We obtained horizontally aligned metallic SWNT arrays with an average density of more than 20 tubes per micrometre in which 90 per cent of the tubes had chiral indices of (12, 6), and semiconducting SWNT arrays with an average density of more than 10 tubes per micrometre in which 80 per cent of the nanotubes had chiral indices of (8, 4). The nanotubes were grown using uniform size Mo2C and WC solid catalysts. Thermodynamically, the SWNT was selectively nucleated by matching its structural symmetry and diameter with those of the catalyst. We grew nanotubes with chiral indices of (2m, m) (where m is a positive integer), the yield of which could be increased by raising the concentration of carbon to maximize the kinetic growth rate in the chemical vapour deposition process. Compared to previously reported methods, such as cloning(5,6), seeding(7,8) and specific-structure-matching growth(9-11), our strategy of controlling the thermodynamics and kinetics offers more degrees of freedom, enabling the chirality of as-grown SWNTs in an array to be tuned, and can also be used to predict the growth conditions required to achieve the desired chiralities.</P>

Gate driver for parallel connection SiC MOSFETs with over-current protection and dynamic current balancing scheme

Zhang, Yimeng,Song, Qingwen,Tang, Xiaoyan,Zhang, Yuming The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.1

In this paper, a SiC MOSFETs gate driver for parallel connections is proposed and implemented. The proposed design enhances the reliability of parallel-connected SiC MOSFETs in high-frequency applications. High-speed over-current protections are applied for both over-voltage and under-voltage situations. In addition, a dynamic balancing current sharing scheme for SiC MOSFETs is proposed for high-speed parallel applications by current feedback and switching delay time compensation. With the proposed design, parallel-connected SiC MOSFETs can work at an operation frequency of 1 MHz with over-current protections. In addition, with the dynamic current balancing scheme, the operation temperature decreases from 115 to 86.9 ℃, while the temperature difference for paralleled devices drops from 25.8 to 1.8 ℃.

Strong, and recyclable thermosets cross-linked by MWCNT/poly(aryl ether ketone) containing furan based on Diels-Alder cycloaddition

Wang Yongpeng,Wang Heng,Zhang Qingwen,Zhang Yingyuan,Yan Pengtao,Liu Mengzhu,Zhang Haibo 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.8

Multi-walked carbon nanotube (MWCNT)/poly(aryl ether ketone) networks cross-linked by Diels-Alder cycloaddition possess outstanding mechanical and rheological properties. Poly(aryl ether ketone) containing pendant furan (PAEK-Fu) was synthesized, which had excellent thermal and mechanical properties, and a series of cross-linked materials with reversible covalent cross-linked crosslinking network were synthesized through a furan/MWCNTs Diels-Alder (D-A) reaction between PAEK-Fu and MWCNTs. Thermal and mechanical properties for MWCNT/PAEK-Fu composites were studied, and after crosslinking, MWCNT/PAEK-Fu composites exhibited good flexibility and resistance against organic solvents. After heating to 180 °C, the cross-linked MWCNT/PAEK-Fu composite membranes could be dissolved in NMP. This work demonstrates that the poly(aryl ether ketone)s can be made into recyclable thermoset materials using the concept of associative dynamic bonding. Given the dramatically increasing interest in environmentally sustainable materials, this MWCNT/poly(aryl ether ketone) interaction mode provides a robust approach to high performance engineering plastics with improved performance compared with the thermoplastic counterparts.

Mesenchymal Stem Cells Combined With Electroacupuncture Treatment Regulate the Subpopulation of Macrophages and Astrocytes to Facilitate Axonal Regeneration in Transected Spinal Cord

Rongyi Zhang,Junhua Wang,Qingwen Deng,Xingru Xiao,Xiang Zeng,Biqin Lai,Ge Li,Yuanhuan Ma,Jingwen Ruan,한인보,Yuan-Shan Zeng,Ying Ding 대한척추신경외과학회 2023 Neurospine Vol.20 No.4

Objective: Herein, we investigated whether mesenchymal stem cells (MSCs) transplantation combined with electroacupuncture (EA) treatment could decrease the proportion of proinflammatory microglia/macrophages and neurotoxic A1 reactive astrocytes and inhibit glial scar formation to enhance axonal regeneration after spinal cord injury (SCI). Methods: Adult rats were divided into 5 groups after complete transection of the spinal cord at the T10 level: a control group, a nonacupoint EA (NA-EA) group, an EA group, an MSC group, and an MSCs+EA group. Immunofluorescence labeling, quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blots were performed. Results: The results showed that MSCs+EA treatment reduced the proportion of proinflammatory M1 subtype microglia/macrophages, but increased the differentiation of anti-inflammatory M2 phenotype cells, thereby suppressing the mRNA and protein expression of proinflammatory cytokines (tumor necrosis factor-α and IL-1β) and increasing the expression of an anti-inflammatory cytokine (interleukin [IL]-10) on days 7 and 14 after SCI. The changes in expression correlated with the attenuated neurotoxic A1 reactive astrocytes and glial scar, which in turn facilitated the axonal regeneration of the injured spinal cord. In vitro, the proinflammatory cytokines increased the level of proliferation of astrocytes and increased the expression levels of C3, glial fibrillary acidic protein, and chondroitin sulfate proteoglycan. These effects were blocked by administering inhibitors of ErbB1 and signal transducer and activator of transcription 3 (STAT3) (AG1478 and AG490) and IL-10. Conclusion: These findings showed that MSCs+EA treatment synergistically regulated the microglia/macrophage subpopulation to reduce inflammation, the formation of neurotoxic A1 astrocytes, and glial scars. This was achieved by downregulating the ErbB1-STAT3 signal pathway, thereby providing a favorable microenvironment conducive to axonal regeneration after SCI.

Novel modulation method for torque ripple suppression of brushless DC motors based on SIMO DC-DC converter

Sun, Shikai,Guo, Hui,Zhang, Yimeng,Jia, Yupeng,Lv, Hongliang,Song, Qingwen,Tang, Xiaoyan,Zhang, Yuming The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.3

In this paper, a novel modulation method is proposed for the torque ripple suppression of a brushless DC motor (BLDCM) during both the commutation period and the speed regulation period. The main sources of torque ripple are the imbalance current during commutation and the PWM during speed regulation. A single-inductor multiple-output (SIMO) Buck DC-DC converter is adopted to generate input voltage for the inverter driver of a BLDCM. During the commutation period, the input voltage of an inverter can be adjusted to four times the back electromotive force (EMF), which suppresses the torque ripple caused by imbalance commutation current. Meanwhile, by changing the output voltage of a SIMO DC-DC, the speed of a BLDCM can be regulated without PWM on the inverter switches, which also suppresses the torque ripple. A control algorithm is applied on a Field Programmable Gate Array (FPGA), and the proposed BLDCM drive prototype is fabricated and tested. Measurement results show that with the proposed speed regulation strategy, the torque ripple is suppressed from 33.3% to 20.1%, and that with the proposed suppression strategy in commutation, the torque ripple is suppressed further to 5.3%.