Effect of Low-Temperature Heat Treatment on PM2.5 Adsorption Properties of GO Films

Weiwu Zou,Baoshan Gu,Shiqing Sun,Shidong Wang,Xin Li,Haoqi Zhao,Peiyan Yang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.15 No.01

To explore the mechanism of GO acting on PM 2.5, a graphene oxide (GO) film was prepared via a spraying method for air purification. The effects of different media, temperature and heat treatment times on the adsorption of PM 2.5 on GO film were investigated. The morphology, composition and structure of GO materials were characterized by scanning electron microscopy (SEM), electron spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FT-IR) and Raman spectroscopy. When the vacuum heat-treatment temperature is below 80 ℃ and the atmospheric heat-treatment temperature is below 100 ℃, the air purification performance of the film does not change significantly. With the increase in the vacuum heat-treatment temperature, the removal efficiency of PM 2.5 by GO film decreases gradually from 95% to 83%. At different times, the vacuum heat treatment increases with time, and the film removal rate shows a downward trend. As the heat-treatment temperature and time increase, a certain redox reaction occurs in the GO, and the air purification performance decreases. At a temperature of 120 ℃ and a time of 8 h, the removal rate drops to 81.68%. The adsorption of PM 2.5 by GO film mainly relies on the action of oxygen-containing functional groups.

Control of the VIV of a cantilevered square cylinder with free-end suction

Li Ying,Li Shiqing,Zeng Lingwei,Wang Hanfeng 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.1

A steady slot suction near the free-end leading edge of a finite-length square cylinder was used to control its aerodynamic forces and vortex-induced vibration (VIV). The freestream oncoming flow velocity (U∞) was from 3.8 m/s to 12.8 m/s. The width of the tested cylinder d = 40 mm and aspect ratio H/d = 5, where H was the height of the cylinder. The corresponding Reynolds number was from 10,400 to 35,000. The tested suction ratio Q, defined as the ratio of suction velocity (Us) at the slot over the oncoming flow velocity at which the strongest VIV occurs (Uv), ranged from 0 to 3. It was found that the free-end slot suction can effectively attenuate the VIV of a cantilevered square cylinder. In the experiments, the RMS value of the VIV amplitude reduced quickly with Q increasing from 0 to 1, then kept approximately constant for Q ≥ 1. The maximum reduction of the VIV occurs at Q = 1, with the vibration amplitude reduced by 92% , relative to the uncontrolled case. Moreover, the overall fluctuation lift of the finite-length square cylinder was also suppressed with the maximum reduction of 87%, which occurred at Q = 1. It was interesting to discover that the free-end shear flow was sensitive to the slot suction near the leading edge. The turbulent kinetic energy (TKE) of the flow over the free end was the highest at Q = 1, which may result in the strongest mixing between the high momentum free-end shear flow and the near wake.

KEPCO-China Huaneng Post-combustion CO2 Capture Pilot Test and Cost Evaluation

Ji Hyun Lee,No Sang Kwak,Hongwei Niu,Jinyi Wang,Shiqing Wang,Hang Shang,Shiwang Gao 한국화학공학회 2020 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.58 No.1

The proprietary post-combustion CO2 solvent (KoSol) developed by the Korea Electric Power Research Institute (KEPRI) was applied at the Shanghai Shidongkou CO2 Capture Pilot Plant (China Huaneng CERI, capacity: 120,000 ton CO2/yr) of the China Huaneng Group (CHNG) for performance evaluation. The key results of the pilot test and data on the South Korean/Chinese electric power market were used to calculate the predicted cost of CO2 avoided upon deployment of CO2 capture technology in commercial-scale coal-fired power plants. Sensitivity analysis was performed for the key factors. It is estimated that, in the case of South Korea, the calculated cost of CO2 avoided for an 960 MW ultra-supercritical (USC) coal-fired power plant is approximately 35~44 USD/tCO2 (excluding CO2 transportation and storage costs). Conversely, applying the same technology to a 1,000 MW USC coal-fired power plant in Shanghai, China, results in a slightly lower cost (32~42 USD/tCO2). This study confirms the importance of international cooperation that takes into consideration the geographical locations and the performance of CO2 capture technology for the involved countries in the process of advancing the economic efficiency of large-scale CCS technology aimed to reduce greenhouse gases.

20(S)-protopanaxadiol and oleanolic acid ameliorate cognitive deficits in APP/PS1 transgenic mice by enhancing hippocampal neurogenesis

Kaili Lin,Stephen Cho-Wing Sze,Bin Liu,Zhang Zhang,Zhu Zhang,Peili Zhu,Ying Wang,Qiudi Deng,Ken Kin-Lam Yung,Shiqing Zhang 고려인삼학회 2021 Journal of Ginseng Research Vol.45 No.2

Background: Alzheimer"s disease (AD) is one of the most prevalent neurodegenerative disorders. Enhancing hippocampal neurogenesis by promoting proliferation and differentiation of neural stem cells (NSCs) is a promising therapeutic strategy for AD. 20(S)-protopanaxadiol (PPD) and oleanolic acid (OA) are small, bioactive compounds found in ginseng that can promote NSC proliferation and neural differentiation in vitro. However, it is currently unknown whether PPD or OA can attenuate cognitive deficits by enhancing hippocampal neurogenesis in vivo in a transgenic APP/PS1 AD mouse model. Here, we administered PPD or OA to APP/PS1 mice and monitored the effects on cognition and hippocampal neurogenesis. Methods: We used the Morris water maze, Y maze, and open field tests to compare the cognitive capacities of treated and untreated APP/PS1 mice. We investigated hippocampal neurogenesis using Nissl staining and BrdU/NeuN double labeling. NSC proliferation was quantified by Sox2 labeling of the hippocampal dentate gyrus. We used western blotting to determine the effects of PPD and OA on Wnt/GSK3β/β-catenin pathway activation in the hippocampus. Results: Both PPD and OA significantly ameliorated the cognitive impairments observed in untreated APP/PS1 mice. Furthermore, PPD and OA significantly promoted hippocampal neurogenesis and NSC proliferation. At the mechanistic level, PPD and OA treatments resulted in Wnt/GSK-3β/β-catenin pathway activation in the hippocampus. Conclusion: PPD and OA ameliorate cognitive deficits in APP/PS1 mice by enhancing hippocampal neurogenesis, achieved by stimulating the Wnt/GSK-3β/β-catenin pathway. As such, PPD and OA are promising novel therapeutic agents for the treatment of AD and other neurodegenerative diseases.

A drug delivery system constructed by a fusion peptide capturing exosomes targets to titanium implants accurately resulting the enhancement of osseointegration peri-implant

Li Xuewen,Liu Zihao,Xu Shendan,Ma Xinying,Zhao Zhezhe,Hu Han,Deng Jiayin,Peng Cheng,Wang Yonglan,Ma Shiqing 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Exosomes derived from bone marrow mesenchymal stem cells (BMSC-exos) have been shown triggering osteogenic differentiation and mineralization of MSCs, but exosomes administered via bolus injections are rapidly sequestered and cleared. Therefore, we considered the implant as a new organ of patient’s body and expected to find a method to treat implant with BMSC-exos in vivo directly.A fusion peptide (PEP), as a drug delivery system (DDS) which contained a titanium-binding peptide (TBP) possessing the ability to selectively bind to the titanium surface and another peptide CP05 being able to capture exosomes expertly, is constructed to modify the titanium surface.Both in vitro and in vivo experiments prove PEP retains the ability to bind titanium and exosome simultaneously, and the DDS gain the ability to target exosomes to titanium implants surface following enhancing osseointegration post-implantation. Moreover, the DDS constructed by exosomes of diverse origins shows the similar combination rate and efficiency of therapy.This drug delivery system demonstrates the concept that EXO-PEP system can offer an accurate and efficient therapy for treating implants with long-term effect.