Mechanical and Tribological Properties of Short Basalt Fiber-reinforced Polyoxymethylene Composites

Chenghe Liu,Chunguang Long,Lei Chen,Junpeng Liu,Taishan Cao,Jian Zhang 한국고분자학회 2016 폴리머 Vol.40 No.6

In this paper, short basalt fiber-reinforced polyoxymethylene (POM) composites were prepared by melt blending and injection molding. The mechanical and tribological properties of the composites were studied by an orthogonal experiment. It was found that the optimal combination of fiber length 4 mm, fiber content 20 wt% and treated with KH550 would result in a comprehensive property which is 27.45% higher tensile strength, 9.65% higher impact strength and 18.11% higher flexural strength with compared to that of pure POM. But its tribological properties would be worse with the addition of the basalt fibers. After incorporating 10 wt% of polytetrafluoroethylene (PTFE) into the composites, the tribological properties of the composites was improved, closed to that of pure POM, with an insignificant decrease to their mechanical properties. Moreover, the morphology of fracture surfaces and worn surfaces evaluated by scanning electron microscopy showed good agreement with the results of the literature.

Phenolic composition and neuroprotective effects of the ethyl-acetate fraction from Inonotus sanghuang against H2O2-induced apoptotic cell death of primary cortical neuronal cells

Kun Liu,Cuilian Qi,Yihang Liu,Huagang Hu,Xuan Xiao,Junpeng Wang,Yaping Huai 한국식품과학회 2022 Food Science and Biotechnology Vol.31 No.9

The study aimed to characterize phenolic compounds of the Inonotus sanghuang’s ethyl-acetate fraction (EAF) and assess the neuroprotective effect of EAF using the H2O2-treated primary cortical neuronal cells (PCNC) model. Using HPLC-ECD, 5 phenolics were identified and quantified from EAF. H2O2-treated PCNC experiments in vitro showed that pretreatment with EAF increased the GSH-PX and SOD activities and reduced the NO, MDA, and Aβ contents. Furthermore, EAF suppressed the production of IL-1β, IFN-γ, IL-6, and TNF-α in H2O2-treated PCNC. Other mechanisms found that EAF reduced Bax, caspase 9, and caspase 3 expressions at the mRNA and protein levels while increasing Bcl-2 expression at the mRNA and protein levels. These results showed that EAF could serve as potential agents for anti-NDD.

Herringbone Structure and Signifi cantly Enhanced Hardness in W-Modifi ed Ti 2 AlNb Alloys by Spark Plasma Sintering

Junpeng Yang,Qi Cai,Yongchang Liu,Chong Li,Zongqing Ma,Huijun Li 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4

The W-modifi ed Ti 2 AlNb-based alloys synthesized at 1100 °C by spark plasma sintering were solution treated at 1300 °Cfor 4 h and then aged at 800–1000 °C for 1 h. The phase composition, microstructure evolution, and microhardness of theaged alloys are investigated in this study. A signifi cant enhancement of hardness, ~ 750 HV, is obtained in the alloy aged at900 °C, while that of the one without W addition is only ~ 470 HV. The hardness is also higher than that of common β-Ti andTi–6Al–4V alloys. As the ageing temperature increases, the B2/O structure evolves from B2 + O colonies to Widmannstättenstructure, followed by a “disordering to ordering” procedure. This process also involves the variation of the angle betweenadjacent O phase from 90° to 60°. Specifi cally, a herringbone Widmannstätten B2 + O structure is constructed in the alloysaged in the α 2 + B2 + O phase region, which is related to the diff usion of W and the substitution of W for Nb in the latticeof B2 or O.

Dynamic Island Partition for Distribution System with Renewable Energy to Decrease Customer Interruption Cost

Junpeng Zhu,Wei Gu,Ping Jiang,Shan Song,Haitao Liu,Huishi Liang,Ming Wu 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.6

When a failure occurs in active distribution system, it will be isolated through the action of circuit breakers and sectionalizing switches. As a result, the network might be divided into several connected components, in which distributed generations could supply power for customers. Aimed at decreasing customer interruption cost, this paper proposes a theoretically optimal island partition model for such connected components, and a simplified but more practical model is also derived. The model aims to calculate a dynamic island partition schedule during the failure recovery time period, instead of a static islanding status. Fluctuation and stochastic characteristics of the renewable distributed generations and loads are considered, and the interruption cost functions of the loads are fitted. To solve the optimization model, a heuristic search algorithm based on the hill climbing method is proposed. The effectiveness of the proposed model and algorithm is evaluated by comparing with an existing static island partitioning model and intelligent algorithms, respectively.

Dynamic Island Partition for Distribution System with Renewable Energy to Decrease Customer Interruption Cost

Zhu, Junpeng,Gu, Wei,Jiang, Ping,Song, Shan,Liu, Haitao,Liang, Huishi,Wu, Ming The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.6

When a failure occurs in active distribution system, it will be isolated through the action of circuit breakers and sectionalizing switches. As a result, the network might be divided into several connected components, in which distributed generations could supply power for customers. Aimed at decreasing customer interruption cost, this paper proposes a theoretically optimal island partition model for such connected components, and a simplified but more practical model is also derived. The model aims to calculate a dynamic island partition schedule during the failure recovery time period, instead of a static islanding status. Fluctuation and stochastic characteristics of the renewable distributed generations and loads are considered, and the interruption cost functions of the loads are fitted. To solve the optimization model, a heuristic search algorithm based on the hill climbing method is proposed. The effectiveness of the proposed model and algorithm is evaluated by comparing with an existing static island partitioning model and intelligent algorithms, respectively.

Research on Flexible Business Process of Bank Modeling Based on EPC

Wang Xia,Man Junpeng,Liu Lan 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.6

As the further development of banking business for personalization and diversification, the bank information system is capable of dynamically adjusting business process and has set higher requirements for the flexible mechanism. This paper constructs a model of the business process based on Event-driven Process Chains (EPC), puts forward the concrete specification in the process of construction. A case study was implemented to validate the model using Pi-calculus. The results show that this model can be a powerful tool for the creation of flexible or customized business process.

The synthesis of MDMO-PPV capped PbS nanorods and their application in solar cells

Zhijie Wang,Shengchun Qu,Xiangbo Zeng,Junpeng Liu,Changsha Zhang,Mingji Shi,Furui Tan,Zhanguo Wang 한국물리학회 2009 Current Applied Physics Vol.9 No.5

Poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) capped PbS nanorods about 100 nm in diameter and 400 nm in length were synthesized via a hydrothermal route in toluene and dimethylsulfoxide solution. By blending the PbS nanorods with the MDMO-PPV as the active layer, bulk heterojunction solar cells with an indium tin oxide (ITO)/polyethylenedioxythiophene/polystyrenesulphonate (PEDOT: PSS)/MDMO-PPV: PbS nanorods/Al structure were fabricated in a N2 filled glove box. Current density–voltage characterization of the devices showed that the solar cells with PbS nanorods hybrid with MDMO-PPV as active layer were better in performance than the devices with the polymer only.

Multicolor tunable luminescence and energy transfer mechanism in a novel single-phase KBaGd(WO₄)₃:Tb³⁺, Eu³⁺ phosphor for NUV WLEDs

Song, Mingjun,Zhao, Wang,Ran, Weiguang,Xue, Junpeng,Liu, Yanliang,Jeong, Jung Hyun Elsevier 2019 JOURNAL OF ALLOYS AND COMPOUNDS Vol.803 No.-

<P><B>Abstract</B></P> <P>In this research, a series of Tb<SUP>3+</SUP> and/or Eu<SUP>3+</SUP> doped KBaGd(WO<SUB>4</SUB>)<SUB>3</SUB> (KBGW for short) phoshpors were prepared by sol-gel method and characterized by X-ray diffraction (XRD), FT-IR and Raman spectra, scanning electron microscope (SEM), excitation and emission spectra, and luminescent decay curves. The results of XRD, SEM, FT-IR and Raman spectra confirmed that a single phase of KBGW with smooth surface and uniform particle size can be synthesized by sol-gel method. Under 250 or 378 nm excitation, multicolor tunable emissions from green to red were achieved in the KBGW:Tb<SUP>3+</SUP>, Eu<SUP>3+</SUP> phosphors by suitably controlling the ratios of Eu<SUP>3+</SUP>/Tb<SUP>3+</SUP>. The energy transfer efficiencies and mechanisms between Eu<SUP>3+</SUP> and Tb<SUP>3+</SUP> were investigated on the basis of photoluminescence (PL) spectra and luminescent decay curves, and a graphic analysis on the energy transfer process between Tb<SUP>3+</SUP> and Eu<SUP>3+</SUP> was presented. The temperature-dependent PL spectra of Eu<SUP>3+</SUP> and/or Tb<SUP>3+</SUP> doped KBGW were recorded and the thermal quenching behavior of the phosphors was analyzed in the framework of crossover model. At the end, green, red and white LEDs were fabricated with the as-prepared KBGW:Tb<SUP>3+</SUP>/Eu<SUP>3+</SUP> phosphors, and the excellent electroluminescence parameters suggest that the KBGW:Tb<SUP>3+</SUP>/Eu<SUP>3+</SUP> phosphors may be a component candidate for NUV excited WLEDs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A color tunable KBaGd(WO<SUB>4</SUB>)<SUB>3</SUB>:Tb<SUP>3+</SUP>/Eu<SUP>3+</SUP> phosphor was firstly prepared by sol-gel method. </LI> <LI> Its morphology, luminescent property and thermal stability were studied in detail. </LI> <LI> The emission color was tuned from green to red by changing the doping ratio of Eu/Tb. </LI> <LI> The energy transfer is demonstrated to be accomplished by dipole-dipole interactions. </LI> <LI> Green, red and white LEDs were fabricated and their performance were investigated. </LI> </UL> </P>

ROS-activated CXCR2+ neutrophils recruited by CXCL1 delay denervated skeletal muscle atrophy and undergo P53-mediated apoptosis

Xiang Yaoxian,Dai Junxi,Li Yao,You Zongqi,Zhang Junpeng,Huang Xinying,Nie Shuqi,Chen Yujie,Xu Lei,Liu Fengming,Jiang Junjian,Xu Jianguang 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Neutrophils are the earliest master inflammatory regulator cells recruited to target tissues after direct infection or injury. Although inflammatory factors are present in muscle that has been indirectly disturbed by peripheral nerve injury, whether neutrophils are present and play a role in the associated inflammatory process remains unclear. Here, intravital imaging analysis using spinning-disk confocal intravital microscopy was employed to dynamically identify neutrophils in denervated muscle. Slice digital scanning and 3D-view reconstruction analyses demonstrated that neutrophils escape from vessels and migrate into denervated muscle tissue. Analyses using reactive oxygen species (ROS) inhibitors and flow cytometry demonstrated that enhanced ROS activate neutrophils after denervation. Transcriptome analysis revealed that the vast majority of neutrophils in denervated muscle were of the CXCR2 subtype and were recruited by CXCL1. Most of these cells gradually disappeared within 1 week via P53-mediated apoptosis. Experiments using specific blockers confirmed that neutrophils slow the process of denervated muscle atrophy. Collectively, these results indicate that activated neutrophils are recruited via chemotaxis to muscle tissue that has been indirectly damaged by denervation, where they function in delaying atrophy.

Electrospun PS/PAN Nanofiber Membranes Formed from Doped Carbon Nanotubes with a Fluffy and Multi-scale Construction for Air-Filtration Materials

Weili Shao,Wanli Yue,Gaihuan Ren,Chen Cui,Junpeng Xiong,Ling Wang,Tong Lu,Wanjun Bu,Fan Liu,Jianxin He 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5

Electrospun nanofibers are widely used in air-filtration materials because of their fine fiber diameter, small poresize, and high porosity. However, nanofiber membranes exhibit a dense structure, such that they present a large resistance toany air flow. In this study, we set out to design and develop composite nanofiber materials with fluffy structures, as well asblended structures of coarse and fine fibers, through electrospinning technology. These materials could be used in airfiltration applications, given that they offer high efficiency and low resistance. The results show that, compared with purePAN nanofibers, the diameter of PAN nanofibers doped with CNT decreased from 192.36 to 124.37 nm; when the spinningratio of PS coarse fiber (1053 nm) and PAN/CNT fine fiber is 3:1, the resulting nanofiber membrane materials has an obviousthree-dimensional structure, with a specific surface area of 103.16 m2/g, a pore size of 2.25 μm, and a quality factor of0.0947 Pa-1. Under test conditions featuring an air flow of 32 L/min, and 0.3 μm NaCl aerosol particles, the filtrationefficiency was 99.37 % and the resistance was 35 Pa. Furthermore, the dust-holding capacity of the nanofiber air-filter paperwas found to be almost the same as that of melt-blown air-filter papers. Even after being water-soaked 50 times, the filteringefficiency of the nanofiber air-filter paper was still higher. Interestingly, the nanofiber membrane materials doped with CNTalso exhibited excellent sound-absorption abilities. Thus, the composite nanofiber material could potentially be applied toareas with serious air pollution and high noise pollution.