Thermal Conductive Epoxy Enhanced by Nanodiamond-Coated Carbon Nanotubes

Bo Zhao,Guohua Jiang 대한금속·재료학회 2017 ELECTRONIC MATERIALS LETTERS Vol.13 No.6

Nanodiamond (ND) particles were coated on the surface of carbonnanotubes (CNTs) by chemical reactions. Reliable bonding wasformed by the combination of acyl chloride on NDs and amine groupon CNTs. ND coated CNTs (CNT-ND) were dispersed into epoxy tofabricate thermal conductive resins. The results show that the surfaceenergy of CNTs is decreased by the coated NDs, which is contributedto the excellent dispersion of CNT-NDs in the epoxy matrix. Theheat-transfer channels were built by the venous CNTs cooperatingwith the coated NDs, which not only plays an effective role of heatconduction for CNTs and NDs, but also avoids the electrical leakageby the protection of NDs surrounding outside of CNTs. Electrical andthermal conductance measurements demonstrate that the influence ofthe CNT-ND incorporation on the electrical conductance is minor,however, the thermal conductivity is improved significantly for theepoxy filled with CNT-ND.

Electrospun Porcine Acellular Dermal Matrix and Polycaprolactone Composite Nanofibrous Scaffolds for Accelerating Wound Healing

Xiaofei Gao,Guohua Jiang,Liming Ruan,Yanfang Sun,Khaydar E. Yunusov,Yanting Jing,Uladzislau E. Aharodnikau,Sergey O. Solomevich 한국섬유공학회 2023 Fibers and polymers Vol.24 No.2

Electrospun nanofibers represent a novel class of scaffold materials that show great potential in wound healing owing torelatively large surface area, better mimicry of native extracellular matrix, adjustable waterproofness and breathability, andprogrammable drug delivery process. In this work, electrospun polycaprolactone (PCL) and porcine acellular dermal matrix(PADM) composite nanofibrous membranes have been developed by electrospinning technology and inflated into threedimensional(3D) structural scaffold (PCL-PADM) by gas foaming method. The obtained PCL-PADM has higher thermalstability, hydrophilicity and better cell adhesion compared with PCL. In addition, ε-polylysine (ε-PL) is further attachedonto the surface of PADM/PCL to offer its good antibacterial properties. Moreover, the PADM/PCL fibrous scaffolds showexcellent cytocompatibility for promoting cell proliferation. In vivo models showed that the resultant PADM/PCL fibrousscaffolds exhibit an accelerating wound healing effect through promoting expression of vascular factor (CD31) and decreasingthe expression of tumor necrosis factor-α (TNF-α). These results indicate that the 3D fibrous scaffolds may be a potentialwound dressing for wound closure.

Electrochemical Deposition of γ-MnO2 on Ag/rGO Hybrid Films as Flexible Electrode Materials for Asymmetric Supercapacitor

Shiqing Sun,Yongkun Liu,Guohua Jiang,Bo Yu,Uwamahoro Evariste,Pianpian Ma 대한금속·재료학회 2019 ELECTRONIC MATERIALS LETTERS Vol.15 No.3

The fl exible electrodes are the essential components for fabricating modern fl exible supercapacitors. In this study, a compositehybrid fi lm integrated with silver nanoparticles (Ag NPs), reduced graphene oxide (rGO) and γ-MnO 2 nanorods asa fl exible electrode has been developed by the electrochemical deposition method. The substrate (rGO) of the electrode notonly provides mechanical stability but also ensures fast electron transfer during charge–discharge. The Ag NPs distributedin electrode provide the electronic channel to enhance the electric conductivity. The γ-MnO 2 electroplated on the surface ofhybrid fi lms further improved the electrochemical performance of them. The resultant γ-MnO 2 /Ag/rGO hybrid fi lms exhibita high specifi c capacitance of 1090.3 F g −1 at current density of 0.3 A g −1 . The asymmetric supercapacitor (ASC) deviceswere further fabricated by γ-MnO 2 /Ag/rGO fi lms as anode and AC/rGO fi lms as cathode electrodes within a wide operatingvoltage of 0–1.7 V. The energy density of obtained ASC devices was 71.8 Wh kg −1 at a power density of 279.4 W kg −1 .

Synthesis and characterization of a K/K2CO3-based solid superbase as a catalyst in propylene dimerization

Haibo Jin,Heng Jiang,Qiwei Wang,Suohe Yang,Guohua Luo,Guangxiang He 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2

A novel solid superbase 3%K/K2CO3 was prepared by loading metallic potassium on K2CO3. The optimized preparation conditions included a loading time of 1.5 h, loading temperature of 150 oC, loading amount of 3wt% and average carrier size of 120 μm. Under the optimum conditions, the conversion of propylene is about 60% with the selectivity of dimers 98.5% and the selectivity of 4MP1 86.3%. In addition, the superbase 3%K/K2CO3 has a base strength of H−≥37, and the concentration of basic sites of H−≥35 is approximately 0.3mmol·g−1 CAT. The microcrystal of metallic potassium was determined using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). It was assumed that the oxygen species, which are adjacent to lattice defects, such as the crystalline corners, edges and vacancies of metallic potassium microcrystals, constituted the superbasic sites.

Synthesis and Characterization of Cobalt-Doped WS ₂ Nanorods for Lithium Battery Applications

Wang, Shiquan,Li, Guohua,Du, Guodong,Li, Li,Jiang, Xueya,Feng, Chuanqi,Guo, Zaiping,Kim, Seungjoo Springer 2010 NANOSCALE RESEARCH LETTERS Vol.5 No.8

<P>Cobalt-doped tungsten disulfide nanorods were synthesized by an approach involving exfoliation, intercalation, and the hydrothermal process, using commercial WS<SUB>2</SUB> powder as the precursor and <I>n</I>-butyllithium as the exfoliating reagent. XRD results indicate that the crystal phase of the sample is 2H-WS<SUB>2</SUB>. TEM images show that the sample consists of bamboo-like nanorods with a diameter of around 20 nm and a length of about 200 nm. The Co-doped WS<SUB>2</SUB> nanorods exhibit the reversible capacity of 568 mAh g<SUP>−1</SUP> in a voltage range of 0.01–3.0 V versus Li/Li<SUP>+</SUP>. As an electrode material for the lithium battery, the Co-doped WS<SUB>2</SUB> nanorods show enhanced charge capacity and cycling stability compared with the raw WS<SUB>2</SUB> powder.</P>

Transcriptome-wide characterization of the WRKY family genes in Lonicera macranthoides and the role of LmWRKY16 in plant senescence

Cao Zhengyan,Wu Peiyin,Gao Hongmei,Xia Ning,Jiang Ying,Tang Ning,Liu Guohua,Chen Zexiong 한국유전학회 2022 Genes & Genomics Vol.44 No.2

Background: Lonicera macranthoides is an important woody plant with high medicinal values widely cultivated in southern China. WRKY, one of the largest transcription factor families, participates in plant development, senescence, and stress responses. However, a comprehensive study of the WRKY family in L. macranthoides hasn't been reported previously. Objective: To establish an extensive overview of the WRKY family in L. macranthoides and identify senescence-responsive members of LmWRKYs. Methods: RNA-Seq and phylogenetic analysis were employed to identify the LmWRKYs and their evolutionary relationships. Quantitative real-time (qRT-PCR) and transgenic technology was utilized to investigate the roles of LmWRKYs in response to developmental-, cold-, and ethylene-induced senescence. Results: A total of 61 LmWRKY genes with a highly conserved motif WRKYGQK were identified. Phylogenetic analysis of LmWRKYs together with their orthologs from Arabidopsis classified them into three groups, with the number of 15, 39, and 7, respectively. 17 LmWRKYs were identified to be differentially expressed between young and aging leaves by RNA-Seq. Further qRT-PCR analysis showed 15 and 5 LmWRKY genes were significantly induced responding to tissue senescence in leaves and stems, respectively. What's more, five LmWRKYs, including LmWRKY4, LmWRKY5, LmWRKY6, LmWRKY11, and LmWRKY16 were dramatically upregulated under cold and ethylene treatment in both leaves and stems, indicating their involvements commonly in developmental- and stress-induced senescence. In addition, function analysis revealed LmWRKY16, a homolog of AtWRKY75, can accelerate plant senescence, as evidenced by leaf yellowing during reproductive growth in LmWRKY16-overexpressing tobaccos. Conclusion: The results lay the foundation for molecular characterization of LmWRKYs in plant senescence.

Physicochemical characteristics of a nanocomposite film based on purified sodium carboxymethylcellulose and selenium nanoparticles

Yunusov Khaydar Ergashovich,Turakulov Fozil Mamaraim Ugli,Sarymsakov Abdushkur Abdukhalilovich,Yuldoshov Sherzod Abdullaevich,Rashidova Sayyora Sharafovna,Guohua Jiang 대한화학회 2024 Bulletin of the Korean Chemical Society Vol.45 No.3

In this study, selenium nanoparticles (SeNPs) were synthesized and stabilized by reducing sodium selenite using ascorbic acid in an aqueous solution of sodium carboxymethylcellulose (Na‐CMC) with a degree of substitution of 0.97 and a degree of polymerization of 810. IR‐Fourier spectroscopy revealed that coordination bonds between functional groups in Na‐CMC and SeNPs resulted in the development of polymer‐metal complexes. UV–Vis spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) methods were used to determine the SeNP sizes in the structure of the nanocomposite film. Investigation of the stabilization and nonstabilization of SeNPs over several cycles has shown that the effect of the polymer matrix of Na‐CMC on the stabilization of nanoparticles was achieved for 672 h, which was confirmed by the unchanged size distribution and resistance to change of the SeNPs synthesized in Na‐CMC solutions. In this study, selenium nanoparticles (SeNPs) were synthesized and stabilized by reducing sodium selenite using ascorbic acid in an aqueous solution of sodium carboxymethylcellulose (Na-CMC) with a degree of substitution of 0.97 and a degree of polymerization of 810. IR-Fourier spectroscopy revealed that coordination bonds between functional groups in Na-CMC and SeNPs resulted in the development of polymer-metal complexes. UV–Vis spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) methods were used to determine the SeNP sizes in the structure of the nanocomposite film. Investigation of the stabilization and nonstabilization of SeNPs over several cycles has shown that the effect of the polymer matrix of Na-CMC on the stabilization of nanoparticles was achieved for 672 h, which was confirmed by the unchanged size distribution and resistance to change of the SeNPs synthesized in Na-CMC solutions.