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81.
Maleated poly(lactic acid) (PLA-g-MA) was prepared through melt grafting of maleic anhydride onto a PLA backbone with the aid of a radical initiator. PLA-g-MA thus formed was incorporated into PLA/polyamide 11 (PA11) blends as a reactive compatibilizer. By morphological observation, it was assessed that PLA-g-MA lowered the interfacial energy and strengthened the interface between PLA and PA11. However, the compatibilized PLA/PA11 blends did not show significant improvement of impact strength compared with noncompatibilized PLA/PA11 blends. Measurements of the molecular weight and impact strength of PLAs compounded with various amounts of radical initiators revealed that decreased molecular weight of PLA by the radical initiator used for the preparation of PLA-g-MA is responsible for this unexpected result. To compensate the decrease of the molecular weight, a crosslinking agent was incorporated in the preparation step of PLA-g-MA. It was found that the crosslinking agent is effective in preventing the molecular weight reduction. As a result, the impact strength of the PLA/PA11 blend was enhanced to a great extent by the PLA-g-MA prepared with the crosslinking agent. 相似文献
82.
Jae-Sung Kim Seok-Jun Mun Euni Cho Donggyu Kim Wooic Son Hye-In Jeon Hyo Keun Kim Kiseok Jang Chul-Su Yang 《International journal of molecular sciences》2020,21(22)
Dense granule proteins (GRAs) are essential components in Toxoplasma gondii, which are suggested to be promising serodiagnostic markers in toxoplasmosis. In this study, we investigated the function of GRA9 in host response and the associated regulatory mechanism, which were unknown. We found that GRA9 interacts with NLR family pyrin domain containing 3 (NLRP3) involved in inflammation by forming the NLRP3 inflammasome. The C-terminal of GRA9 (GRA9C) is essential for GRA9–NLRP3 interaction by disrupting the NLRP3 inflammasome through blocking the binding of apoptotic speck-containing (ASC)-NLRP3. Notably, Q200 of GRA9C is essential for the interaction of NLRP3 and blocking the conjugation of ASC. Recombinant GRA9C (rGRA9C) showed an anti-inflammatory effect and the elimination of bacteria by converting M1 to M2 macrophages. In vivo, rGRA9C increased the anti-inflammatory and bactericidal effects and subsequent anti-septic activity in CLP- and E. coli- or P. aeruginosa-induced sepsis model mice by increasing M2 polarization. Taken together, our findings defined a role of T. gondii GRA9 associated with NLRP3 in host macrophages, suggesting its potential as a new candidate therapeutic agent for sepsis. 相似文献
83.
Eun-Ok Oh Chin-Myung Whang Yu-Ri Lee Jong-Heun Lee Kyung Joong Yoon Byung-Kook Kim Ji-Won Son Jong-Ho Lee Hae-Weon Lee 《Journal of the European Ceramic Society》2012,32(8):1733-1741
A 500 nm thick thin film YSZ (yttria-stabilized zirconia) electrolyte was successfully fabricated on a conventionally processed anode substrate by spin coating of chemical solution containing slow-sintering YSZ nanoparticles with the particle size of 20 nm and subsequent sintering at 1100 °C. Incorporation of YSZ nanoparticles was effective for suppressing the differential densification of ultrafine precursor powder by mitigating the prevailing bi-axial constraining stress of the rigid substrate with numerous local multi-axial stress fields around them. In particular, adding 5 vol% YSZ nanoparticles resulted in a dense and uniform thin film electrolyte with narrow grain size distribution, and fine residual pores in isolated state. The thin film YSZ electrolyte placed on a rigid anode substrate with the GDC (gadolinia-doped ceria) and LSC (La0.6Sr0.4CoO3?δ) layers deposited by PLD (pulsed laser deposition) processes revealed that it had fairly good gas tightness relevant to a SOFC (solid oxide fuel cell) electrolyte and maintained its structural integrity during fabrication and operation processes. In fact, the open circuit voltage was 1.07 V and maximum power density was 425 mW/cm2 at 600 °C, which demonstrates that the chemical solution route can be a viable means for reducing electrolyte thickness for low- to intermediate-temperature SOFCs. 相似文献
84.
Won Seok Lyoo Hyun Seok Lee Byung Chul Ji Sung Soo Han Kang Koo Sam Soo Kim Joon Ho Kim Joon‐Seok Lee Tae Won Son Won Sik Yoon 《应用聚合物科学杂志》2001,81(14):3471-3480
Melt‐spun poly(trimethylene terephthalate) (PTT) fibers were zone‐drawn and the structures and properties of the fibers were investigated in consideration of the spinning and zone‐drawing conditions. The draw ratio increased up to 4 with increasing drawing temperature to 180°C, at a maximum drawing stress of 220 MPa. Higher take‐up velocity gave lower drawability of the fiber. The PTT fiber taken up at 4000 rpm was hardly drawn, in spite of using maximum drawing stress, because a high degree of orientation had been achieved in the spinning procedure. However, an additional enhancement of birefringence was observed, indicating a further orientation of PTT molecules by zone drawing. The exotherm peak at 60°C disappeared and was shifted to a lower temperature with an increase in the take‐up velocity, which means that the orientation and crystallinity of the fiber increased. The d‐spacing of (002) plane increased with increasing take‐up velocity and draw ratio, whereas those of (010) and (001) planes decreased. In all cases, the crystal size increased with take‐up velocity and draw ratio. The cold‐drawn PTT fiber revealed a kink band structure, which disappeared as the drawing temperature was raised. The physical properties of zone‐drawn PTT fibers were improved as the draw ratio and take‐up velocity increased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3471–3480, 2001 相似文献
85.
Strength improvement and purification of Yb2Si2O7‐SiC nanocomposites by surface oxidation treatment 下载免费PDF全文
Son T. Nguyen Tadachika Nakayama Hisayuki Suematsu Tsuneo Suzuki Lingfeng He Hong‐Baek Cho Koichi Niihara 《Journal of the American Ceramic Society》2017,100(7):3122-3131
A two‐step processing was developed to prepare Yb2Si2O7‐SiC nanocomposites. Yb2Si2O7‐Yb2SiO5‐SiC composites were first fabricated by a solid‐state reaction/hot‐pressing method. The composites were then annealed at 1250°C in air for 2 hours to activate the oxidation of SiC, which effectively transformed the Yb2SiO5 into Yb2Si2O7. The surface cracks purposely induced can be fully healed during the oxidation treatment. The treated composites have improved flexural strength compared to their pristine composites. The mechanism for crack healing and silicate transformation have been proposed and discussed in detail. 相似文献
86.
Comparative study of Al2O3, HfO2, and HfAlOx for improved self‐compliance bipolar resistive switching 下载免费PDF全文
Andrey S. Sokolov Seok Ki Son Donghwan Lim Hoon Hee Han Yu‐Rim Jeon Jae Ho Lee Changhwan Choi 《Journal of the American Ceramic Society》2017,100(12):5638-5648
The comparison of resistive switching (RS) storage in the same device architecture is explored for atomic layer deposition (ALD) Al2O3, HfO2 and HfAlOx‐based resistive random access memory (ReRAM) devices. Among them, the deeper high‐ and low‐ resistance states, more uniform VSET‐VRES, persistent ROFF/RON (>102) ratio and endurance up to 105 cycles during both DC and AC measurements were observed for HfAlOx‐based device. This improved behavior is attributed to the intermixing of amorphous Al2O3/HfO2 oxide layers to form amorphous thermally stable HfAlOx thin films by consecutive‐cycled ALD. In addition, the higher oxygen content at Ti/HfAlOx thin films interface was found within the energy dispersive spectroscopy analysis (EDS). We believe this higher oxygen content at the interface could lead to its sufficient storage and supply, leading to the stable filament reduction‐oxidation operation. Further given insight to the RS mechanism, SET/RESET power necessities and scavenging effect shed a light to the enhancement of HfAlOx‐based ReRAM device as well. 相似文献
87.
The effects of solution properties and polyelectrolyte on the electrospinning of poly(ethylene oxide) (PEO) solutions were investigated. Ultrafine PEO fibers without beads were electrospun from 3, 4, 7 and 7 wt% PEO solutions in chloroform, ethanol, (dimethylformamide) DMF and water, respectively. At these concentrations, the values of [η]C were ∼10 for all solutions. The average diameters of PEO fibers were ranged from 0.36 to 1.96 μm. The higher the dielectric constant of solvent was, the thinner PEO fiber was. The average diameters of electrospun PEO fibers from PEO/water solutions were decreased and their distributions were narrowed by adding 0.1 wt% poly(allylamine hydrochloride) (PAH) and poly(acrylic acid sodium salt) (PAA) due to the increased charge density in solutions. The addition of PAH and PAA lowered the minimum concentration for electrospinning of a PEO/water solution to 6 wt%. 相似文献
88.
Taeseon Hwang Joon Suk Oh Jung-Pyo Hong Gi-Yong Nam Ah-Hyun Bae Sang-Ik Son Geun-Ho Lee Hak-Kyung Sung Youngkwan Lee Jae-Do Nam 《Carbon》2012,50(2):612-621
Few-layer graphene (FLG) was investigated as an electrically-conductive interleaf layer for one-step electroplating and patterning of metal on nonconductive polymer substrates without using multiple and toxic pretreatment processes in traditional electroplating. An individual FLG (5–10 nm of thickness with 6.4% of oxygen content) was obtained by expanding graphite with microwave followed by exfoliating the expanded graphite with sonication in N-methyl-pyrrolidone. Stacking FLG in the in-plane direction, a robust FLG film was obtained by the vacuum-assisted filtering and drying methods, and transferred to a polyethylene terephthalate (PET) substrate via an intermediate transfer to the water surface. The sheet resistance of the FLG film on the PET substrate was 0.9 kΩ/sq with a thickness of 80 nm and the root-mean-square roughness of 29 nm. In the electroplating of nickel on the FLG film, hemisphere-shape metal seeds appeared in the early stage of electroplating and they subsequently grew up to 200–480 nm, which became connected to form a continuous nickel layer. The thickness of the continuous nickel layer increased linearly with electroplating time. The developed electroplating method demonstrated its capability of selective patterning on nonconductive substrates using a simple masking technique. 相似文献
89.
Zinc sulfide [ZnS] thin films were deposited on glass substrates using radio frequency magnetron sputtering. The substrate
temperature was varied in the range of 100°C to 400°C. The structural and optical properties of ZnS thin films were characterized
with X-ray diffraction [XRD], field emission scanning electron microscopy [FESEM], energy dispersive analysis of X-rays and
UV-visible transmission spectra. The XRD analyses indicate that ZnS films have zinc blende structures with (111) preferential
orientation, whereas the diffraction patterns sharpen with the increase in substrate temperatures. The FESEM data also reveal
that the films have nano-size grains with a grain size of approximately 69 nm. The films grown at 350°C exhibit a relatively
high transmittance of 80% in the visible region, with an energy band gap of 3.79 eV. These results show that ZnS films are
suitable for use as the buffer layer of the Cu(In, Ga)Se2 solar cells. 相似文献
90.
Polyaniline (PANI) has been utilized very well as an active material for hazardous acid detection device. Because its electrical conductivity is developing when it is doped with the protonic acid. However, a critical disadvantage of this material is its insolubility in general solvents so its processability is very poor. In this work, we prepared a Chitosan‐g‐PANI (Cs‐g‐PANI) copolymer to improve its solubility and prossability using common solvents and use film form of the final product to develop a sensitive device, which responds to the presence of hazardous acids. The synthetic Cs‐g‐PANI showing good solubility and excellent film forming properties was characterized by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, as well as X‐ray diffraction analysis, and scanning electron microscopy. The physical properties of Cs‐g‐PANI films were optimized by controlling the Cs composition. Constant potential was applied to this material for detecting the existence of hazardous acids such as hydrochloric acid (HCl), nitric acid, formic acid, and acetic acid. Our findings suggest that this device responds to the presence of HCl faster than any other acids. The detection mechanism is discussed in detail. POLYM. ENG. SCI., 59:E105–E110, 2019. © 2018 Society of Plastics Engineers 相似文献