Carbon Nanotube Fiber Based Stretchable Wire-Shaped Supercapacitors

Xu, Ping,Gu, Taoli,Cao, Zeyuan,Wei, Bingqing,Yu, Jianyong,Li, Faxue,Byun, Joon-Hyung,Lu, Weibang,Li, Qingwen,Chou, Tsu-Wei Wiley Blackwell (John Wiley Sons) 2014 ADVANCED ENERGY MATERIALS Vol.4 No.3

Spatial strain variation of graphene films for stretchable electrodes

Xu, Ping,Kang, Junmo,Suhr, Jonghwan,Smith, Joseph P.,Booksh, Karl S.,Wei, Bingqing,Yu, Jianyong,Li, Faxue,Byun, Joon-Hyung,Oh, Youngseok,Chou, Tsu-Wei Elsevier 2015 Carbon Vol.93 No.-

<P><B>Abstract</B></P> <P>Graphene films fabricated by chemical vapor deposition are promising electrode materials for stretchable energy storage devices. The buckled four-layer graphene on a polydimethylsiloxane film substrate subject to various applied tensile strains has been characterized by atomic force microscopy and micro-Raman mapping. The small redshift of 2D band and the indiscernible D band demonstrated that the tensile strains of up to 40% only induced a strain variation of less than 0.2% and did not cause any observable damage in the graphene film. This study has confirmed that the graphene film in the buckled state is suitable for its application as a stretchable electrode.</P>

Laminated Ultrathin Chemical Vapor Deposition Graphene Films Based Stretchable and Transparent High-Rate Supercapacitor

Xu, Ping,Kang, Junmo,Choi, Jae-Boong,Suhr, Jonghwan,Yu, Jianyong,Li, Faxue,Byun, Joon-Hyung,Kim, Byung-Sun,Chou, Tsu-Wei American Chemical Society 2014 ACS NANO Vol.8 No.9

<P>Due to their exceptional flexibility and transparency, CVD graphene films have been regarded as an ideal replacement of indium tin oxide for transparent electrodes, especially in applications where electronic devices may be subjected to large tensile strain. However, the search for a desirable combination of stretchability and electrochemical performance of such devices remains a huge challenge. Here, we demonstrate the implementation of a laminated ultrathin CVD graphene film as a stretchable and transparent electrode for supercapacitors. Transferred and buckled on PDMS substrates by a prestraininig-then-buckling strategy, the four-layer graphene film maintained its outstanding quality, as evidenced by Raman spectra. Optical transmittance of up to 72.9% at a wavelength of 550 nm and stretchability of 40% were achieved. As the tensile strain increased up to 40%, the specific capacitance showed no degradation and even increased slightly. Furthermore, the supercapacitor demonstrated excellent frequency capability with small time constants under stretching.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2014/ancac3.2014.8.issue-9/nn503570j/production/images/medium/nn-2014-03570j_0008.gif'></P>

Stretchable Wire-Shaped Asymmetric Supercapacitors Based on Pristine and MnO₂ Coated Carbon Nanotube Fibers

Xu, Ping,Wei, Bingqing,Cao, Zeyuan,Zheng, Jie,Gong, Ke,Li, Faxue,Yu, Jianyong,Li, Qingwen,Lu, Weibang,Byun, Joon-Hyung,Kim, Byung-Sun,Yan, Yushan,Chou, Tsu-Wei American Chemical Society 2015 ACS NANO Vol.9 No.6

<P>While the emerging wire-shaped supercapacitors (WSS) have been demonstrated as promising energy storage devices to be implemented in smart textiles, challenges in achieving the combination of both high mechanical stretchability and excellent electrochemical performance still exist. Here, an asymmetric configuration is applied to the WSS, extending the potential window from 0.8 to 1.5 V, achieving tripled energy density and doubled power density compared to its asymmetric counterpart while accomplishing stretchability of up to 100% through the prestrainning-then-buckling approach. The stretchable asymmetric WSS constituted of MnO<SUB>2</SUB>/CNT hybrid fiber positive electrode, aerogel CNT fiber negative electrode and KOH-PVA electrolyte possesses a high specific capacitance of around 157.53 μF cm<SUP>–1</SUP> at 50 mV s<SUP>–1</SUP> and a high energy density varying from 17.26 to 46.59 nWh cm<SUP>–1</SUP> with the corresponding power density changing from 7.63 to 61.55 μW cm<SUP>–1</SUP>. Remarkably, a cyclic tensile strain of up to 100% exerts negligible effects on the electrochemical performance of the stretchable asymmetric WSS. Moreover, after 10 000 galvanostatic charge–discharge cycles, the specific capacitance retains over 99%, demonstrating a long cyclic stability.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-6/acsnano.5b01244/production/images/medium/nn-2015-012442_0007.gif'></P>

A Feeder Impedance Identification Based Droop Control Method for Accurate Reactive Power Sharing in Islanded Microgrids

Jianyong Zhao,Jian Li,Heng Nian,Lei Yang,Bao Gai,Zaiping Pan,Yourui Xu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Due to the unmatched feeder impedance, the conventional voltage and frequency droop control method is unable to accurately allocate the output reactive power of DG units in proportion to their power ratings. To solve this issue, this paper has proposed a feeder impedance identification based droop control method. Firstly, the relationship among the reactive power sharing, reactive power droop slope and feeder impedance in islanded microgrids is illustrated. An online feeder impedance identification method is subsequently adopted to modify the reactive power droop slope of DG unit. In this way, the effect of unmatched feeder impedance on reactive power sharing is eliminated without communication among DG units. Experimental results implemented on an islanded microgrid apparatus have validated the feasibility of the proposed droop control method.

Multi-scale Nano/Micro Fiber Scaffolds with Different Topological Morphologies

Jianyong Feng,Ruixiang Xu,Jiaming Zhao,Lingxiao Zhang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.4

The multi-scale fiber and topological morphologies had been shown to influence cell mitogenesis and chemotaxis,direct cell differentiation, and induce constructive host tissue remodeling responses. To simulate multi-layer meshworkarchitecture of extracellular matrix and regulate cell behavior, we prepared different topological scaffolds, such as 3Dprinting fiber scaffolds, poly(lactic acid) (PLA) electrospun fiber scaffolds, 3D printing/knitted fabric composite scaffolds,and PLA electrospinning/knitted fabric composite scaffolds. The surface morphology, pore diameter, thickness, stress-straincurve, electrical current, and other properties were studied. The aim is to prepare multi-scale nano/micro fiber scaffolds withdifferent topological morphologies and properties that can provide structural and mechanical support for potential tissueengineering applications.

Synchronous Periodic Frequency Modulation Based on Interleaving Technique to Reduce PWM Vibration Noise

Zhang, Wentao,Xu, Yongxiang,Ren, Jingwei,Su, Jianyong,Zou, Jibin The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6

Ear-piercing high-frequency noise from electromagnetic vibrations in motors has become unacceptable in sensitive environments, due to the application of pulse width modulation (PWM) and in consideration of switching losses. This paper proposed a synchronous periodic frequency modulation (SPFM) method based on the interleaving technique for paralleled three-phase voltage source inverters (VSIs) to eliminate PWM vibration noise. The proposed SPFM technique is able to effectively remove unpleasant high-frequency vibration noise as well as acoustic noise more effectively than the conventional periodic carrier frequency modulation (PCFM) and interleaving technique. It completely eliminates the vibration noise near odd-order carrier frequencies and reduces the PWM vibration noise near even-order carrier frequencies depending on the switching frequency variation range. Furthermore, the SPFM method is simple to implement and does not employ additional circuits in the drive system. Finally, the effectiveness of the proposed method has been confirmed by detailed experimental results.

Synchronous Periodic Frequency Modulation Based on Interleaving Technique to Reduce PWM Vibration Noise

Wentao Zhang,Yongxiang Xu,Jingwei Ren,Jianyong Su,Jibin Zou 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6

Ear-piercing high-frequency noise from electromagnetic vibrations in motors has become unacceptable in sensitive environments, due to the application of pulse width modulation (PWM) and in consideration of switching losses. This paper proposed a synchronous periodic frequency modulation (SPFM) method based on the interleaving technique for paralleled three-phase voltage source inverters (VSIs) to eliminate PWM vibration noise. The proposed SPFM technique is able to effectively remove unpleasant high-frequency vibration noise as well as acoustic noise more effectively than the conventional periodic carrier frequency modulation (PCFM) and interleaving technique. It completely eliminates the vibration noise near odd-order carrier frequencies and reduces the PWM vibration noise near even-order carrier frequencies depending on the switching frequency variation range. Furthermore, the SPFM method is simple to implement and does not employ additional circuits in the drive system. Finally, the effectiveness of the proposed method has been confirmed by detailed experimental results.

A new terpene coumarin microbial transformed by Mucor polymorphosporus induces apoptosis of human gastric cancer cell line MGC-803

Guangzhi Li,Junchi Wang,Xiaojin Li,Jianguo Xu,Zhao Zhang,Jianyong Si 대한약학회 2018 Archives of Pharmacal Research Vol.41 No.6

20-Z auraptene (1) is a synthesized monoterpenecoumarin with anticancer activity against human gastriccancer cells. In order to find new potential anticancer agent,Mucor polymorphosporus was used to transform cis-auraptene. Four new terpene coumarins with notable changesin the skeletal backbone, 20-Z auraptene A-D (2–5), wereobtained and evaluated for their antiproliferative effectsagainst human normal gastric epithelium cells and humangastric cancer cells. These new compounds showed selectivecytotoxic activity against MGC-803 cells with IC50values from 0.78 ± 0.13 to 10.78 ± 1.83 lM and thetherapeutic index could also be significantly improved(TI = 59.0) compared with that of 1 (TI = 5.5). Thestructures of these metabolites were elucidated throughextensive spectroscopic methods, and the possible biotransformationpathway of 1 by Mucor polymorphosporuswas also proposed. Furthermore, the mechanism of theantiproliferative effects against MGC-803 cells of the mostpotent compound, 20-Z auraptene A (2), was characterized. Annexin V/PI staining and abnormal expression of apoptosis-related protein suggested that compound 2 inducesapoptosis in gastric cancer MGC-803 cells. Therefore, it ispossible that compound 2 has the potential to be applied ingastric cancer therapy.

Altered microRNA Expression Profiles of Extracellular Vesicles in Nasal Mucus From Patients With Allergic Rhinitis

Geping Wu,Guanghai Yang,Ruxin Zhang,Guangyin Xu,Ling Zhang,Wu Wen,Jianbing Lu,Jianyong Liu,Yan Yu 대한천식알레르기학회 2015 Allergy, Asthma & Immunology Research Vol.7 No.5

Purpose: Allergic rhinitis (AR) is an inflammatory disorder of the upper airway. Exosomes or extracellular vesicles are nanosized vesicles of endosomal origin released from inflammatory and epithelial cells that have been implicated in allergic diseases. In this study, we characterized the microRNA (miRNA) content of exosomes in AR. Methods: Extracellular vesicles were isolated from nasal mucus from healthy control subjects (n=10) and patients with severe AR (n=10). Vesicle RNA was analyzed by using a TaqMan microRNA assays Human Panel-Early Access kit (Applied Biosystems, Foster City, CA, USA) containing probes for 366 human miRNAs, and selected findings were validated with quantitative RT-PCR. Target prediction and pathway analysis for the differentially expressed miRNAs were performed using DIANA-mirPath. Results: Twenty-one vesicle miRNAs were up -regulated and 14 miRNAs were under-regulated significantly (P<0.05) in nasal mucus from AR patients when compared to healthy controls. Bioinformatic analysis by DIANA-mirPath demonstrated that 32 KEGG biological processes were significantly enriched (P<0.05, FDR corrected) among differentially expressed vesicle miRNA signatures. Among them, the B-cell receptor signaling pathway (P=3.709E-09), the natural killer cell-mediated cytotoxicity (P=8.466E-05), the T-cell receptor signaling pathway (P=0.00075), the RIG-I-like receptor signaling pathway (P=0.00127), the Wnt signaling pathway (P=0.00130), endocytosis (P=0.00440), and salivary secretion (P=0.04660) were the most prominent pathways enriched in quantiles with differential vesicle miRNA patterns. Furthermore, miR-30-5p, miR-199b-3p, miR-874, miR-28-3p, miR-203, and miR-875-5p, involved in B-cell receptor and salivary secretion signaling pathways, were selected for validation using independent samples from 44 AR patients and 20 healthy controls. MiR-30-5p and miR-199b-3p were significantly increased in extracellular vesicles from nasal mucus when compared to healthy controls, while miR-874 and miR-28-3p were significantly down-regulated. In addition, miRNA-203 was significantly increased in AR patients, while miRNA-875-5p was found to be significantly decreased in AR patients. Conclusions: This study demonstrated that vesicle miRNA may be a regulator for the development of AR.