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排序方式: 共有174条查询结果,搜索用时 31 毫秒
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When dispensing liquid through a piezoelectric inkjet nozzle, a single droplet without a satellite is formed in the limited range of the Ohnesorge number. Especially, it is difficult to eject low viscosity fluids such as a silver nanoparticle suspension in the form of a single free drop using conventional single waveforms to drive the piezoelectric actuators. To overcome the lower limit of fluid viscosity, in the present study, double waveforms with two square pulses have been applied to control the droplet formation in the piezoelectric inkjet nozzle and its response has been observed. With regard to the double waveforms, the effect of the driving voltage and time separation between the pulses was investigated. The present nozzle shows that several satellites are produced by the successive ejection in a single pulse because the oscillating pressure wave is rarely damped out in the low viscosity fluid. On the other hand, a single droplet is easily formed in the double waveform and the droplet formation could be precisely controlled by changing the time separation between the pulses. The upper and lower limits of the time separation are discussed in view of the kinetic phenomena of a primary drop and a transient satellite for the low viscosity fluid. In addition, it is addressed how the time separation and driving voltage in the double waveform affect the droplet size and velocity. 相似文献
134.
Riaz Ahmad Amjad Khan Inayat Ur Rehman Hyeon Jin Lee Ibrahim Khan Myeong Ok Kim 《International journal of molecular sciences》2022,23(11)
Traumatic brain injury (TBI) signifies a major cause of death and disability. TBI causes central nervous system (CNS) damage under a variety of mechanisms, including protein aggregation, mitochondrial dysfunction, oxidative stress, and neuroinflammation. Astrocytes and microglia, cells of the CNS, are considered the key players in initiating an inflammatory response after injury. Several evidence suggests that activation of astrocytes/microglia and ROS/LPO have the potential to cause more harmful effects in the pathological processes following traumatic brain injury (TBI). Previous studies have established that lupeol provides neuroprotection through modulation of inflammation, oxidative stress, and apoptosis in Aβ and LPS model and neurodegenerative disease. However, the effects of lupeol on apoptosis caused by inflammation and oxidative stress in TBI have not yet been investigated. Therefore, we explored the role of Lupeol on antiapoptosis, anti-inflammatory, and antioxidative stress and its potential mechanism following TBI. In these experiments, adult male mice were randomly divided into four groups: control, TBI, TBI+ Lupeol, and Sham group. Western blotting, immunofluorescence staining, and ROS/LPO assays were performed to investigate the role of lupeol against neuroinflammation, oxidative stress, and apoptosis. Lupeol treatment reversed TBI-induced behavioral and memory disturbances. Lupeol attenuated TBI-induced generation of reactive oxygen species/lipid per oxidation (ROS/LPO) and improved the antioxidant protein level, such as nuclear factor erythroid 2-related factor 2 (Nrf2) and heme-oxygenase 1 (HO-1) in the mouse brain. Similarly, our results indicated that lupeol treatment inhibited glial cell activation, p-NF-κB, and downstream signaling molecules, such as TNF-α, COX-2, and IL-1β, in the mouse cortex and hippocampus. Moreover, lupeol treatment also inhibited mitochondrial apoptotic signaling molecules, such as caspase-3, Bax, cytochrome-C, and reversed deregulated Bcl2 in TBI-treated mice. Overall, our study demonstrated that lupeol inhibits the activation of astrocytes/microglia and ROS/LPO that lead to oxidative stress, neuroinflammation, and apoptosis followed by TBI. 相似文献
135.
Jeong Myeong Lee Yoon Gon Kim Seung Jin Lee Hee Su Kim Sung Pil Yoon Suk Woo Nam Soon Do Yoon Jeong Woo Yun 《Journal of Applied Electrochemistry》2014,44(5):581-588
Samarium-doped ceria (SDC) is coated onto a Ni/yttria-stabilized zirconia (Ni/YSZ) anode for the direct use of methane in solid-oxide fuel cells. Porous SDC thin layer is applied to the anode using the sol–gel coating method. The experiment was performed in H2 and CH4 conditions at 800 °C. The cell performance was improved by approximately 20 % in H2 conditions by the SDC coating, due to the high ionic conductivity, the mixed ionic and electronic conductive property of the SDC, and the increased triple phase boundary area by the SDC coating in the anode. Carbon was hardly deposited in the SDC-coated Ni/YSZ anode. The cell performance of the SDC-coated Ni/YSZ anode did not show any significant degradation for up to 90 h under 0.1 A cm?2 at 800 °C. The porous thin SDC coating on the Ni/YSZ anode provided the electrochemical oxidation of CH4 over the whole anode, and minimized the carbon deposition by electrochemical carbon oxidation. 相似文献
136.
Shailima Rampogu Gihwan Lee Jun Sung Park Keun Woo Lee Myeong Ok Kim 《International journal of molecular sciences》2022,23(3)
Recently, the world has been witnessing a global pandemic with no effective therapeutics yet, while cancer continues to be a major disease claiming many lives. The natural compound curcumin is bestowed with multiple medicinal applications in addition to demonstrating antiviral and anticancer activities. In order to elucidate the impact of curcumin on COVID-19 and cancer, the current investigation has adapted several computational techniques to unfold its possible inhibitory activity. Accordingly, curcumin and similar compounds and analogues were retrieved and assessed for their binding affinities at the binding pocket of SARS-CoV-2 main protease and DDX3. The best binding pose was escalated to molecular dynamics simulation (MDS) studies to assess the time dependent stability. Our findings have rendered one compound that has demonstrated good molecular dock score complemented by key residue interactions and have shown stable MDS results inferred by root mean square deviation (RMSD), radius of gyration (Rg), binding mode, hydrogen bond interactions, and interaction energy. Essential dynamics results have shown that the systemadapts minimum energy conformation to attain a stable state. The discovered compound (curA) could act as plausible inhibitor against SARS-CoV-2 and DDX3. Furthermore, curA could serve as a chemical scaffold for designing and developing new compounds. 相似文献
137.
Sung Hwan Min Jin Goo Lee Ok Sung Jeon Myeong Geun Park Kwang Hyun Ryu Jae-ha Myung Yong-Gun Shul 《Ceramics International》2018,44(1):433-437
Ba(Zr0.1Ce0.7Y0.2)O3-δ nano-particles were prepared by different wet-chemical synthesis, Pechini (BZCY(P)) and co-precipitation (BZCY(C)), respectively. The BZCY(C) powders have a particle size in range of about 50–150 nm, which is smaller than the BZCY(P) powders with about 500–900 nm. Both the BZCY materials show perovskite structures, but there are impurities in the BZCY (P). Moreover, the electrolyte density was higher in the BZCY (C) than the BZCY (P). The single cells with BZCY (C) electrolytes exhibited about 0.23 W cm?2 at 600 °C and about 0.31 W cm?2 at the same temperature were obtained when the anode-functional layer was introduced between the anode and electrolyte. Thus, the BZCY prepared by carbonate-derived co-precipitation method can be more favorable for high-purity and dense electrolytes in the solid oxide fuel cells than the BZCY prepared by Pechini method. 相似文献
138.
Kim Jinjoo Cho Kumsun Kim Joo Sung Jung Hyun Chae Kim Bumsik Park Myeong Soo Ji Geun Eog Cho Joo-Youn Hong Kyoung Sup 《Food science and biotechnology》2020,29(6):837-844
Food Science and Biotechnology - There have been many studies suggesting that probiotics are effective in patients with diarrhea-predominant irritable bowel syndrome (IBS-D). However, its mechanism... 相似文献
139.
Effect of seed moisture content on the grinding kinetics,yield and quality of soybean oil 总被引:1,自引:0,他引:1
Grinding kinetics of soybeans at different moisture content (6%, 8% and 12%) were investigated. The hardness of soybean particles increased and showed brittle characters as the moisture content decreased. Three theoretical models for grinding, such as the Rittinger, Kick, and Bond model, were applied to characterize the grinding process of soybeans. The lower moisture content showed less grinding constants including Bond’s work index. Sigmoid model was successfully applied to describe the changes in particle size of soybeans at different moisture contents during grinding (r2 > 0.96). The TBARS (thiobarbituric acid reactive substances) at different size of soybean flours were measured at 25 °C and 50 °C for 20 days and the yield of oil composition at different size of soybean flours were measured. As the particle sizes decreased, the TBARS values increased during storage, while the oil yield from soybean flours increased. 相似文献
140.
Jaeseong Hwang Seungjun Myeong Wooyoung Jin Haeseong Jang Gyutae Nam Moonsu Yoon Su Hwan Kim Se Hun Joo Sang Kyu Kwak Min Gyu Kim Jaephil Cho 《Advanced materials (Deerfield Beach, Fla.)》2020,32(34):2001944
Li- and Mn-rich layered oxides (LMRs) have emerged as practically feasible cathode materials for high-energy-density Li-ion batteries due to their extra anionic redox behavior and market competitiveness. However, sluggish kinetics regions (<3.5 V vs Li/Li+) associated with anionic redox chemistry engender LMRs with chemical irreversibility (first-cycle irreversibility, poor rate properties, voltage fading), which limits their practical use. Herein, the structural origin of this chemical irreversibility is revealed through a comparative study involving Li1.15Mn0.51Co0.17Ni0.17O2 with relatively localized and delocalized excess-Li in its lattice system. Operando fine-interval X-ray absorption spectroscopy is used to simultaneously observe the interplay between transition-metal–oxygen (TM-O) redox chemistry and TM migration behavior in real time. Density functional theory calculations show that excess-Li localization in the LMR structure attenuates TM-O covalency and stability, leading to overall chemical irreversibility. Hence, the delocalized excess-Li system is proposed as an alternative design for practically feasible LMR cathodes with restrained TM migration and sustainable O-redox chemistry. 相似文献