Expression profiles of antimicrobial peptides in honeybee, Apis mellifera, treated with five pesticides

JooHeon Cha,YeongHo Kim,HeeJin Kim,Young Ho Kim 한국응용곤충학회 2023 한국응용곤충학회 학술대회논문집 Vol.2023 No.04

Synergistic interaction between pseudocapacitive Fe₃O₄ nanoparticles and highly porous silicon carbide for high-performance electrodes as electrochemical supercapacitors

Kim, Myeongjin,Kim, Jooheon IOP 2017 Nanotechnology Vol.28 No.19

<P>Composites of micro- and mesoporous SiC flakes (SiCF) and ferroferric oxide (Fe<SUB>3</SUB>O<SUB>4</SUB>), SiCF/Fe<SUB>3</SUB>O<SUB>4</SUB>, were prepared via the chemical deposition of Fe<SUB>3</SUB>O<SUB>4</SUB> on SiCF by the chemical reduction of an Fe precursor. The SiCF/Fe<SUB>3</SUB>O<SUB>4</SUB> electrodes were fabricated at different Fe<SUB>3</SUB>O<SUB>4</SUB> feeding ratios to determine the optimal Fe<SUB>3</SUB>O<SUB>4</SUB> content that can maintain a high total surface area of SiCF/Fe<SUB>3</SUB>O<SUB>4</SUB> composites as well as cause a vigorous redox reaction, thereby maximizing the synergistic effect between the electric double-layer capacitive effects of SiCF and the pseudo-capacitive effects of Fe<SUB>3</SUB>O<SUB>4</SUB>. The SiCF/Fe<SUB>3</SUB>O<SUB>4</SUB> electrode fabricated with a Fe<SUB>3</SUB>O<SUB>4</SUB>/SiCF feeding ratio of 1.5:1 (SiCF/Fe<SUB>3</SUB>O<SUB>4</SUB>(1.5)) exhibited the highest charge storage capacity, showing a specific capacitance of 423.2 F g<SUP>−1</SUP> at a scan rate of 5 mV s<SUP>−1</SUP> with a rate performance of 81.8% from 5 to 500 mV s<SUP>−1</SUP> in an aqueous 1 M KOH electrolyte. The outstanding capacitive performance of the SiCF/Fe<SUB>3</SUB>O<SUB>4</SUB>(1.5) electrode could be attributed to the harmonious synergistic effect between the electric double-layer capacitive contribution of the SiCF and the pseudocapacitive contribution of the Fe<SUB>3</SUB>O<SUB>4</SUB> nanoparticles introduced on the SiCF surface. These encouraging results demonstrate that the SiCF/Fe<SUB>3</SUB>O<SUB>4</SUB>(1.5) electrode is a promising high-performance electrode material for use in supercapacitors.</P>

A p-nitroaniline redox-active solid-state electrolyte for battery-like electrochemical capacitive energy storage combined with an asymmetric supercapacitor based on metal oxide functionalized β-polytype porous silicon carbide electrodes

Kim, Myeongjin,Yoo, Jeeyoung,Kim, Jooheon The Royal Society of Chemistry 2017 Dalton Transactions Vol.46 No.20

<▼1><P>A unique redox active flexible solid-state asymmetric supercapacitor with ultra-high capacitance and energy density was fabricated.</P></▼1><▼2><P>A unique redox active flexible solid-state asymmetric supercapacitor with ultra-high capacitance and energy density was fabricated using a composite comprising MgCo2O4 nanoneedles and micro and mesoporous silicon carbide flakes (SiCF) (SiCF/MgCo2O4) as the positive electrode material. Due to the synergistic effect of the two materials, this hybrid electrode has a high specific capacitance of 516.7 F g<SUP>−1</SUP> at a scan rate of 5 mV s<SUP>−1</SUP> in a 1 M KOH aqueous electrolyte. To obtain a reasonable matching of positive and negative electrode pairs, a composite of Fe3O4 nanoparticles and SiCF (SiCF/Fe3O4) was synthesized for use as a negative electrode material, which shows a high capacitance of 423.2 F g<SUP>−1</SUP> at a scan rate of 5 mV s<SUP>−1</SUP>. Therefore, by pairing the SiCF/MgCo2O4 positive electrode and the SiCF/Fe3O4 negative electrode with a redox active quasi-solid-state PVA-KOH-<I>p</I>-nitroaniline (PVA-KOH-PNA) gel electrolyte, a novel solid-state asymmetric supercapacitor device was assembled. Because of the synergistic effect between the highly porous SiCF and the vigorous redox-reaction of metal oxides, the hybrid nanostructure electrodes exhibited outstanding charge storage and transport. In addition, the redox active PVA-KOH-PNA electrolyte adds additional pseudocapacitance, which arises from the nitro-reduction and oxidation and reduction process of the reduction product of <I>p</I>-phenylenediamine, resulting in an enhancement of the capacitance (a specific capacitance of 161.77 F g<SUP>−1</SUP> at a scan rate of 5 mV s<SUP>−1</SUP>) and energy density (maximum energy density of 72.79 Wh kg<SUP>−1</SUP> at a power density of 727.96 W kg<SUP>−1</SUP>).</P></▼2>

Highly dispersible laser activate particles via surface modification for laser direct structuring and electroless plating application

Kim, Kiho,Ryu, Seokgyu,Kim, Jooheon SAGE Publications 2019 Journal of composite materials Vol.53 No.10

Introduction of Co₃O₄ into activated honeycomb-like carbon for the fabrication of high performance electrode materials for supercapacitors

Kim, Myeongjin,Oh, Ilgeun,Ju, Hyun,Kim, Jooheon The Royal Society of Chemistry 2016 Physical chemistry chemical physics Vol.18 No.13

<P>In this work, a three-dimensional hierarchical carbon framework/Co3O4 hybrid composite was fabricated. The three-dimensional hierarchical carbon framework was constructed by thermal vapor deposition on the silica nanosphere templates and etching these templates. The resulting carbon framework was activated using phosphoric acid to control its surface area and porosity. The degree of activation of the carbon framework was optimized by measuring the specific capacitance. The carbon framework electrode activated with 3 M phosphoric acid (HCCA(3)) exhibited the highest specific capacitance (134 F g(-1) at 10 mV s(-1)). Subsequently, Co3O4 was formed on the carbon framework via the hydrothermal method. The resulting product HCCA(3)/Co3O4 showed a dramatic enhancement in the specific capacitance (456 F g(-1) at 1 A g(-1)) compared with the pristine Co3O4 and HCCA(3) electrodes. The proposed HCCA(3)/Co3O4 composite can be used for the fabrication of high-performance electrodes.</P>

Fabrication of graphene–carbon nanotube papers decorated with manganese oxide nanoneedles on the graphene sheets for supercapacitors

Kim, Myeongjin,Hwang, Yongseon,Kim, Jooheon The Royal Society of Chemistry 2014 Physical chemistry chemical physics Vol.16 No.1

<P>Herein, 3D nanohybrid architectures consisting of MnO<SUB>2</SUB> nanoneedles, carbon nanotubes (CNTs) and graphene sheets are fabricated. Nanostructured ternary hybrid papers in which MnO<SUB>2</SUB> nanoneedles formed on the outermost graphene layer and CNTs intercalated between graphene layers by using the amide bonds are fabricated using the direct paper dipping method. The intercalated CNTs can separate the graphene layers and thus create the effective surface area which is associated with large electrochemically active sites as well as form the electronic conductive channel inside the nanohybrid paper. Moreover, the homogeneous dispersion of nanometer-thick MnO<SUB>2</SUB> on the outermost graphene layer can maximize the surface area which can form pores for ion-buffering reservoirs to improve the diffusion rate of electrolyte ions and enable convenient participation in the pseudo-capacitive reaction. These nanostructured ternary hybrid papers exhibit enhanced specific capacitances compared with graphene-only or graphene–CNT papers. The proposed nanohybrid architectures are expected to lay the foundation for the design and fabrication of high-performance electrodes.</P> <P>Graphic Abstract</P><P>Herein, 3D nanohybrid architectures consisting of MnO<SUB>2</SUB> nanoneedles, carbon nanotubes (CNTs) and graphene sheets are fabricated. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3cp53488j'> </P>

Pyrolysis behavior of polysilazane and polysilazane-coated-boron nitride for high thermal conductive composite

Kim, Kiho,Ju, Hyun,Kim, Jooheon Elsevier 2017 Composites science and technology Vol.141 No.-

<P><B>Abstract</B></P> <P>A thermally conductive composite was fabricated using a BN filler and an epoxy matrix. Because of electrostatic repulsion force, the BN/epoxy composite had poor interfacial affinity, which led to a decrease in the thermal conductivity. To enhance the interfacial affinity, pre-ceramic polysilazane (PSZ) was introduced onto the BN surface and it was sintered in various conditions. PSZ was converted to different structure depended on pyrolysis conditions. After the pyrolysis, the PSZ was converted into a SiOC ceramic in nitrogen atmosphere, and to SiO<SUB>2</SUB> and ash in air atmosphere. The thermal conductivity of the BN-PSZ/epoxy composite decreased as the pyrolysis temperature was increased because of the decomposition of polar functional groups. Pyrolysis at 300 °C in nitrogen atmosphere yielded the highest performance, resulting in an increase in the thermal conductivity to 3.521 W m<SUP>−1</SUP>K<SUP>−1</SUP> at 70 wt% of filler, which was a 1.35-fold increase compared with the raw BN/epoxy composite.</P>

Polyphenylene sulfide/liquid crystal polymer blend system for laser direct structuring and electroless plating applications

Kim, Kiho,Oh, Hyunwoo,Kwon, Dohyun,Lee, Jaewook,Kim, Jooheon Elsevier Science Ltd 2019 Composites Part B, Engineering Vol.166 No.-

<P><B>Abstract</B></P> <P>A super-engineering-plastic polyphenylene sulfide (PPS)-based composite was fabricated for circuit board application. A small amount of liquid crystal polymer (LCP) was blended with PPS in order to enhance the copper plating performance. In addition, 8 wt% of laser activated particles (LAPs) were added to the polymer blend. LCP/LAP exhibited a better interfacial affinity than that of PPS/LAP. A weakly layered structure was observed for the PPS–LCP blend due to flowability difference of two polymers; LCP was flow to surface during injection molding. These layered structure and interfacial affinity difference led the LAP leaning, a small number of LAPs were observed at the PPS dominant region, while a larger amount was observed at the LCP dominant region. Moreover, the mechanical property, circuit building speed and adhesion of copper circuit also improved after the LCP blend. Therefore, laser direct structuring and electroless plating applicable PPS composite was fabricated vis LCP blend.</P>

Thermal and electrical conductivity of Al(OH)3 covered graphene oxide nanosheet/epoxy composites

Kim, Jiwon,Im, Hyungu,Kim, Jong-min,Kim, Jooheon Springer-Verlag 2012 JOURNAL OF MATERIALS SCIENCE - Vol.47 No.3

Hierarchical porous silicon carbide with controlled micropores and mesopores for electric double layer capacitors

Kim, Myeongjin,Oh, Ilgeun,Kim, Jooheon Elsevier 2015 Journal of Power Sources Vol.282 No.-

<P><B>Abstract</B></P> <P>Three-dimensional hierarchical micro and mesoporous silicon carbide spheres (MMPSiC) are prepared by the template method and carbonization reaction via the aerosol spray drying method. The mesopores are generated by the self-assembly of the structure-directing agents, whereas the micropores are derived from the partial evaporation of Si atoms during carbonization. To investigate the effect of mesopore size on electrochemical performance, three types of MMPSiC with different mesopore size were fabricated by using three different structure directing agents (cetyltriethylammonium bromide (CTAB), Polyethylene glycol hexadecyl ether (Brij56), and Poly(ethylene glycol)-<I>block</I>-poly(propylene glycol)-<I>block</I>-poly(ethylene glycol) (P123)). The MMPSiC electrode prepared with Brij56 exhibits the highest charge storage capacity with a specific capacitance of 253.7 F g<SUP>−1</SUP> at a scan rate of 5 mV s<SUP>−1</SUP> and 87.9% rate performance from 5 to 500 mV s<SUP>−1</SUP> in 1 M Na<SUB>2</SUB>SO<SUB>4</SUB> aqueous electrolyte. The outstanding electrochemical performance might be because of the ideal mesopore size, which effectively reduces the resistant pathways for ion diffusion in the pores and provides a large accessible surface area for ion transport/charge storage. These encouraging results demonstrate that the MMPSiC prepared with Brij56 is a promising candidate for high performance electrode materials for supercapacitors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Micropores are derived by partial evaporation of Si atoms during the carbonization. </LI> <LI> Mesopores were generated by self-assembly of the structure directing agent. </LI> <LI> Micro- and mesoporous SiC are studied as cathode for capacitor in 1 M Na<SUB>2</SUB>SO<SUB>4</SUB>. </LI> <LI> The material has specific capacitance of 253.7 F g<SUP>−1</SUP> with a scan rate of 5 mV s<SUP>−1</SUP>. </LI> </UL> </P>