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There is a growing demand for the development of a melt process-based nanocomposite manufacturing process capable of minimizing the incorporation of expensive carbon nanotubes (CNTs) by inducing a uniform dispersion of multi-walled CNTs (MWNTs). In this study, we proposed a nanocomposite manufacturing process that includes both physical particle mixing using high-speed rotation and anionic polymerization of e-caprolactam (CL) to induce a uniform dispersion of MWNTs. MWNTs were uniformly dispersed by powder mixing and then wrapped with polyamide 6 polymers by in-situ polymerization of CL. The synergistic effect of the two sub-processes resulted in an enhanced dispersion of MWNTs and prevented aggregation of the MWNTs. The composites fabricated by the proposed process exhibited electrical conductivities of 4.49 × 10−5 S/m and 1.45 × 10 S/m at 1 wt% and 3 wt% MWNTs, respectively, indicating that by applying the proposed process it is possible to incorporate a smaller amount of MWNT to achieve electrical conductivities applicable for electrostatic discharge (ESD) (>1 X 10−5 S/m) and electromagnetic interference shielding effectiveness (EMI SE) (>10 S/m) applications. An ESD chip tray and EMI SE mobile phone case were fabricated using the prepared composite, and it was verified that the ESD and EMI SE performances can be realized.

Techniques for optimizing the dispersion of carbon nanotubes in composites by applying small amounts of additives in a simple manner are recognized as one of the most important core technologies in nanocomposite engineering. In this study, we reported the feasibility of phenyl glycidyl ether (PGE) as an effective noncovalent functionalization agent and suggested a facile and low-temperature process that applied high-speed rotation based on a planetary centrifugal mixer to improve the dispersion of multiwalled carbon nanotube (MWCNT) in the polyamide 6 (PA6) composite. PGE molecules were introduced on MWCNTs based on the π-π* interaction, resulting in enhanced MWCNT dispersion by preventing of the aggregation between the MWCNTs due to the van der Waals force. The tensile strength of the PA6 composite fiber filled with 1 wt% MWCNTs was improved up to 31.8% by the PGE treatment, indicating that PGE molecules were an effective noncovalent functionalization agent.

Synthetic natural gas (SNG) from syngas is considered a promising substitute for fossil fuels because of its environmental advantages; however, its heating value is below the standard heating value (especially in South Korea and Japan). In this study, bimetallic Co-Fe catalysts were developed for the production of C2-C4 hydrocarbons for usage as mixing gases to improve the heating value of SNG. The effect of the process conditions on the catalytic behavior was investigated. Catalyst 5Co-15Fe/γ-Al2O3 showed the best results with 91.2% CO conversion, 28.2% C2-C4 selectivity, and 0.98 paraffin ratio at H2/CO = 3.0 and 300 °C.

Sulfide-based lithium superionic conducting solid electrolytes for all-solid-state lithium batteries have received much attention due to their high safety, ionic conductivity, and compatibility. However, high-temperature treatment over a long time is needed to achieve high ionic conductivity. In this work, we have prepared the dual-halide-based Li7P2S8X type lithium superionic conductors by dry ball mill process and the high ionic conducting phase was achieved by low temperature (200℃) heat-treatment process. High ionic conducting halogen-halogen composition was arrived at through a series of optimization processes. Among the compositions tested, the Li7P2S8Br0.25I0.75 solid electrolyte exhibited a high ionic conductivity value of 6.16 mS cm−1, at room temperature. The ionic radius of the halogen element played an important role in the formation of the high ionic conducting phase. Further, the ionic conductivity of Li7P2S8I0.75Br0.25 solid electrolyte was improved by metal doping at P-site. The Sn-doped Li7P2S8I0.75Br0.25 solid electrolyte exhibited a high ionic conductivity value of 7.78 mS cm−1, at room temperature. The addition of large-sized Sn atoms extended the crystal lattice parameters and increased the Li-ions transport path. The partial substitution of Sn atoms at P-site was confirmed by NMR and Laser Raman analysis. The electrochemical stability of the prepared solid electrolyte was studied by cyclic voltammetry and DC charge-discharge analysis. The addition of a metal atom to the Li7P2S8Br0.25I0.75 solid electrolyte decreased the side reaction with the Li metals. Thus, low-temperature treated metal-doped Li7P2S8Br0.25I0.75 solid electrolytes are highly favourable for the fabrication of high-performance all-solid-state batteries. The fabricated all-solid-state battery using Sn doped Li7P2S8Br0.25I0.75 solid electrolyte exhibited the high specific capacity value of 170 mAh g−1 (0.1C), at room temperature.

This study aimed to evaluate the effect of noninvasive electrical stimulation (ES) using transcutaneous direct current on facial nerve crush injury by assessing in vitro cellular responses including proliferation and differentiation using PC12 cells as well as by performing in vivo functional and morphological assessments. Compared to the non-treated cells, the cells subjected to ES treatment showed clear in vitro neurite outgrowth and enhanced expression of differentiation genes. In this animal model, functional assessment of recovery was performed using vibrissa movement orientation and electrically stimulated muscle action potential. Moreover, histological observation was performed using a transmission electron microscope. A higher score of recovered vibrissa movement and more significant reduction of the threshold of electrically evoked muscle action potential were observed in the ES group than in the control group. Furthermore, histomorphometric evaluation showed that the experimental group had statistically significantly higher axon counts than did the control group. Regenerative nerve fibers were prominent in the distal segments of the ES group.

Numerous studies have been reported on thermal interface materials based on synergistic hybrid effects, however, most of them contain only fragmentary experimental results and the related model has been rarely proposed to explain the effects exactly. Herein, the thermal conductivities of the composites were systematically evaluated according to various filler contents and ratios. It was found that the fraction of the secondary filler inducing the maximum synergistic effect decreased as the total filler content increased. In addition, when the fraction was higher than the optimum fraction, the anti-synergistic effect occurred. At the optimum fraction, effective phonon transfer was induced due to the improved filler network formation of graphene nanoplatelet (GNP)-carbon nanotube (CNT), thereby achieving high thermal conductivity of 7.69 W/m·K at fGNP = 27.69 vol% and fCNT = 0.57 vol%. Moreover, the Kim-Jang-Lee (KJL) model for the synergistic effect was proposed by introducing filler-ratio variables into the critical percolation equation reported previously, and the KJL model for the anti-synergistic effect was proposed based on the rule of mixture of composites filled with the optimal connected filler network and filled with the excessive secondary filler.

The nanoscopic characteristics of the multi-walled carbon nanotubes (MWCNTs) used in composites are crucial for attempting to understand and design nanocomposites of a novel class. We investigate the correlations between the nanofiller properties and effective electrical properties of MWCNT-embedded polycarbonate composites by theoretical and experimental approaches. A probabilistic computational model is proposed to predict the influence of MWCNT morphology on the electrical behaviors of MWCNTs-embedded polymer composites. A parameter optimization method in accordance with a genetic algorithm is then applied to the model, resulting that the ideal sets of model constant for the simulation are computationally estimated. For the experimental validation purpose, a comparison between the present theoretical and experimental results is made to assess the capability of the proposed methods. In overall, good agreement between the predictions and experimental results can be observed and the electrical performance of the composites can be improved as the MWCNT length increases.

With the recent demand for miniaturization and integration of electronic devices, there has been a growing interest in device malfunction due to high temperature. In this study, a experimental and theoretical study on the composites with improved thermal conductivity by dispersing multi-walled carbon nanotubes (MWCNTs) in the thermoplastic resin was carried out. A micromechanical model was derived based on the ensemble volume-averaging method and the modified Eshelby’s tensor reflecting the interface properties. The effects of the waviness, interface, and orientation of fillers on the thermal conductivity of composites were numerically analyzed. A computational intelligence-based particle swarm optimization (PSO) algorithm was adopted to the proposed model for optimizing the model constants. The thermal conductivity of the polymerized cyclic butylene terephthalate (pCBT)/MWCNT composites was experimentally measured according to the content of MWCNT. Finally, the experimentally measured data were utilized in the PSO to improve the predictive capability of the proposed model.

In order to develop a nanocomposite film based on multi-walled carbon nanotubes (MWCNTs) as an electromagnetic wave shielding material, we propose a solvent-free melting process for fabricating highly dispersed MWCNT-filled polymer composite films with high electrical conductivity and electromagnetic interference (EMI)-shielding properties. By observing aggregates (particles larger than 0.7 μm) using X-ray micro-computed tomography (micro-CT), the uniform dispersion of the MWCNT fillers in the composite films was confirmed. Furthermore, the electrical conductivity and EMI shielding effectiveness (SE) values calculated using percolation and Simon's equations, respectively, were confirmed to agree with experimental data, indicating excellent MWCNT dispersion. The fabricated composites exhibited excellent electrical conductivity, EMI SE, and EMI specific SE (SSE) values of 4.33 S/cm, 30 dB, and of 24.8 dBcm3g−1, respectively, and the EMI SSE value was as good as metal levels. The proposed solvent-free process can be contributed to the commercialization of EMI SE composite films based on MWCNTs.

The anisotropic development of thermal conductivity in polymer composites was evaluated by measuring the isotropic, in-plane and through-plane thermal conductivities of composites containing length-adjusted short and long multi-walled CNTs (MWCNTs). The thermal conductivities of the composites were relatively low irrespective of the MWCNT length due to their high contact resistance and high interfacial resistance to polymer resins, considering the high thermal conductivity of MWCNTs. The isotropic and in-plane thermal conductivities of long-MWCNT-based composites were higher than those of short-MWCNT-based ones and the trend can accurately be calculated using the modified Mori-Tanaka theory. The in-plane thermal conductivity of composites with 2 wt% long MWCNTs was increased to 1.27 W/m·K. The length of MWCNTs in polymer composites is an important physical factor in determining the anisotropic thermal conductivity and must be considered for theoretical simulations. The thermal conductivity of MWCNT polymer composites can be effectively controlled in the processing direction by adjusting the length of the MWCNT filler.

We prepared electrospun polymer nanofibers by the electrospinning method and investigated about their applications to dye-sensitized solar cells (DSSCs). Electrospun poly(vinylidenefluoride–co-hexafluoropropylene) (PVDF–HFP) and PVDF–HFP/polystyrene (PS) blend nanofibers were prepared and examined the uptake, the ionic conductivity, and the porosity by impedance measurement and Scanning Electron Microscope (SEM). The best results of Voc, Jsc, FF, and efficiency of the DSSC devices using the electrospun PVDF–HFP/PS(3:1) blend nanofibers were 0.76 V, 11.8 mA/cm2, 0.66, and 5.75% under AM 1.5.

We prepared poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibers by the electrospinning method and applied to the polymer matrix in polymer electrolytes for dye-sensitized solar cells (DSSCs). The uptake, ionic conductivity, and porosity of the electrospun PVDF-HFP nanofiber films showed 653±50%, 4.53±1.3×10−3 S/cm, and 70±2.3%, respectively, regardless of the diameter and morphology of nanofibers. In addition, several DSSC devices using the electrospun PVDF-HFP nanofiber films as the polymer matrix were prepared to investigate the photovoltaic effect of iodine (I2) concentrations on DSSC devices. With an increase of I2 concentration in electrolyte solutions, the ionic conductivity increased, while the photocurrent density of DSSC devices decreased.

Conventional urine cytology has a poor prognostic performance for detecting bladder cancer, particularly for low-grade tumors. Fluorescence in situ hybridization (FISH) for chromosomes altered in bladder cancer and testing for antigens selectively expressed in tumors are promising alternatives. This study investigated the use of FISH for detecting aneuploidy of chromosomes 3, 7, 17, and 9p21 and reverse transcriptase PCR (RT-PCR) for the expression of melanoma associated antigen (MAGE) genes for the diagnosis of bladder cancer in voided urine specimens. The two techniques were compared with cystoscopic bladder biopsy results in 47 patients with urothelial cancer and 15 patients with benign prostatic hyperplasia. FISH detected cancer in 42 of 47 patients (89.4%). This was significantly higher than the detection rate 30 of 47 patients (64.3%) by MAGE RT-PCR (P < 0.001). The sensitivity of FISH increased with histologic grade and stage of the tumors, correctly identifying 77.8% of pTa and pTis, 94.1% of pT1, and 100% of Pt2-4 tumors. MAGE, however, showed a decreased sensitivity in high grade advanced tumors; it was positive in 66.7% of pTa and pTis, 70.6% of pT1, and 50% of Pt2-4 tumors. Together, the tests correctly identified urothelial cancer in 46 of 47 patients (97.9%). Combined FISH and MAGE RT-PCR testing may offer a promising alternative to conventional urine cytology in screening high-risk populations and in monitoring bladder cancer patients for recurrent tumor.