Facile fabrication of copper oxide modified activated carbon composite for efficient CO2 adsorption

Guanghui Chen,Fei Wang,Shougui Wang,Cailin Ji,Weiwen Wang,Jipeng Dong,Fei Gao 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.1

Copper oxide modified activated carbon (CuO/AC) composites for the CO2 capture were synthesized via a facile assembly strategy associated with a direct solid-state heat dispersion process by introducing CuO into AC using Cu(NO3)2 as the copper source. The synthesized CuO/AC composites with various CuO contents were characterized by powder X-ray diffraction, scanning electron microscopy and nitrogen adsorption-desorption measurement, and the CO2 adsorption performance was investigated. The characterization results indicate that the Cu(NO3)2 species was well dispersed into the AC pore channels and then converted to a highly dispersed CuO after the activation process. The adsorption results reveal that the CO2 adsorption performance can be significantly improved by introducing CuO onto the AC surfaces, and the CuO(0.6)/AC composite with a CuO loading of 0.6mmol/g AC shows a high CO2 adsorption capacity and adsorption selectivity and displays an excellent reversibility. Additionally, the calculated adsorption heat values of CO2 on the CuO(0.6)/AC composite are in the range of 27.3 to 33.9 kJ/mol.

Computational fluid dynamics study on the anode feed solid polymer electrolyte water electrolysis

Shuguo Qu,Guanghui Chen,Jihai Duan,Weiwen Wang,Jianlong Li 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.6

A steady-state two-dimensional model for the anode feed solid polymer electrolyte water electrolysis (SPEWE) is proposed in this paper. Finite element procedure was employed to calculate the multicomponent transfer model coupled with fluid flow in flow channels and gas diffusion layers and electrochemical kinetics in catalyst reactive surface. The performance of the anode feed SPEWE predicted by this model was compared with the published experimental results and reasonable agreement was reached. The results show that oxygen mass fraction increases because of the water oxidation when water flows from the import to the export on the anode side. On the cathode side, hydrogen mass fraction varies little since hydrogen and water mix well. The flux of water across the electrolyte increased almost linearly with the increase of the applied current density. Since the ohmic overpotential loss increasing as the solid polymer electrolytes’ thickness increasing, the performance of the anode feed SPEWE with Nafion 112, 115, 117 decreases at the same applied current density.

Anti-disturbance Position Sensorless Control of PMSM Based on Improved Sliding Mode Observer with Suppressed Chattering and No Phase Delay

Xu Yanping,Wang Chen,Yuan Weiwen,Li Zhifang,Yin Zhonggang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4

In the position sensorless control of permanent magnet synchronous motor (PMSM), the traditional sliding mode observer (SMO) uses the switching function, which presents serious chattering. Otherwise, the traditional SMO uses a low-pass filter to filter the harmonic components in the estimated back-EMF. The low-pass filter usually causes phase delay in the estimated rotor position. These problems restrict the further development of SMO. In this paper, an improved sliding mode observer (ISMO) with suppressed chattering and no phase delay is studied. In the ISMO, a sine saturation function is designed as the control function, and a synchronous reference frame filter (SRFF) is designed to eliminate the phase delay of ISMO. Different from other filters, the SRFF can not only filter out the harmonic components in the estimated back-EMF, but also effectively makes the phase delay almost zero. In addition, in order to improve the poor anti-disturbance performance of position sensorless control, a load disturbance observer (LDO) is introduced on the basis of the ISMO. The experimental results prove the effectiveness of the ISMO, and the addition of LDO improves the anti-disturbance ability of the system.

Evolutionary Rates and Phylogeographical Analysis of Odontoglossum Ringspot Virus Based on the 166 Coat Protein Gene Sequences

Zhen He,Tingting Dong,Weiwen Wu,Wen Chen,Xian Liu,Liangjun Li 한국식물병리학회 2019 Plant Pathology Journal Vol.35 No.5

Odontoglossum ringspot virus (ORSV) is a member of the genus Tobamovirus. It is one of the most prevalent viruses infecting orchids worldwide. Earlier studies reported the genetic variability of ORSV isolates from Korea and China. However, the evolutionary rate, timescale, and phylogeographical analyses of ORSV were unclear. Twenty-one coat protein (CP) gene sequences of ORSV were determined in this study, and used them together with 145 CP sequences obtained from GenBank to infer the genetic diversities, evolutionary rate, timescale and migration of ORSV populations. Evolutionary rate of ORSV populations was 1.25 × 10−3 nucleotides/site/y. The most recent common ancestors came from 30 year ago (95% confidence intervals, 26- 40). Based on CP gene, ORSV migrated from mainland China and South Korea to Taiwan island, Germany, Australia, Singapore, and Indonesia, and it also circulated within east Asia. Our study is the first attempt to evaluate the evolutionary rates, timescales and migration dynamics of ORSV.

p53 overexpression represses androgen-mediated induction ofNKX3.1 in a prostate cancer cell line

Anli Jiang,Chunxiao Yu,Pengju Zhang,Weiwen Chen,Wenwen Liu,Xiaoyan Hu,Jianye Zhang 생화학분자생물학회 2006 Experimental and molecular medicine Vol.38 No.6

Prostate cancer is a disease involving complicated multiple-gene alterations. Both NKX3.1 and p53 are related to prostate cancer and play crucial roles in prostate cancer progression. However, little is known about the relationships and interactions between p53 and NKX3.1 in prostate cancer. We found that NKX3.1 expression is down-regulated by over-expression of wild type (wt) p53 in prostate cancer LNCaP cells. NKX3.1 is down-regulated at both the mRNA and protein levels by p53 overexpression due to either transient transfection of exogenous p53 or induction of endogenous p53. p53 over-expression represses androgen-induced transactivation of NKX3.1 by inhibiting the promoter of the androgen acceptor (AR) gene and by blocking AR-DNA binding activity. In addition, transfection with the p21 expression vector (pPSA-p21) showed that p21 does not reduce NKX3.1 expression, indicating that NKX3.1 expression is not the result of nonspecific effects of cell growth arrest. Our results provide biochemical and cellular biologic evidence that NKX3.1 is down-regulated by p53 over-ex - pression in prostate cancer cells.

Sterically hindered amine-functionalized MCM-41 composite for efficient carbon dioxide capture

Fei Gao,Cailin Ji,Shougui Wang,Weiwen Wang,Jipeng Dong,Changqing Guo,Yuwen Gao,Guanghui Chen 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.8

A new adsorbent based on sterically hindered amine for efficient CO2 capture was prepared. Mesoporoussilicon MCM-41 was modified by sterically hindered amine AMPD (2-amino-2-methyl-1,3-propanediol) in differentAMPD loadings by a facile solid-state self-assembly approach. The physicochemical properties of the MCM-41@AMPDcomposites were analyzed using XRD, BET, FT-IR and SEM, and the composites were investigated for the CO2 captureperformance, including CO2 capture capacity, adsorption selectivity and cycling stability. Characterization analysesshowed that the AMPD active components were successfully incorporated and well dispersed into the mesoporous siliconMCM-41 surfaces. Adsorption results suggest that the modification by the active ingredient AMPD can significantlyimprove the CO2 capture performance. The MCM-41@AMPD material with an AMPD loading of 7mmol∙g1MCM-41 support exhibits a good CO2 adsorption capacity and CO2 adsorption selectivity, and shows excellent cyclingstability. Furthermore, the isosteric heat of CO2 adsorption on the MCM-41@AMPD-7 material was evaluated by theClausius-Clapeyron equation, and the value was 34-78 kJ∙mol1.

Evolutionary Rates and Phylogeographical Analysis of Odontoglossum Ringspot Virus Based on the 166 Coat Protein Gene Sequences

He, Zhen,Dong, Tingting,Wu, Weiwen,Chen, Wen,Liu, Xian,Li, Liangjun The Korean Society of Plant Pathology 2019 Plant Pathology Journal Vol.35 No.5

Odontoglossum ringspot virus (ORSV) is a member of the genus Tobamovirus. It is one of the most prevalent viruses infecting orchids worldwide. Earlier studies reported the genetic variability of ORSV isolates from Korea and China. However, the evolutionary rate, timescale, and phylogeographical analyses of ORSV were unclear. Twenty-one coat protein (CP) gene sequences of ORSV were determined in this study, and used them together with 145 CP sequences obtained from GenBank to infer the genetic diversities, evolutionary rate, timescale and migration of ORSV populations. Evolutionary rate of ORSV populations was $1.25{\times}10^{-3}nucleotides/site/y$. The most recent common ancestors came from 30 year ago (95% confidence intervals, 26-40). Based on CP gene, ORSV migrated from mainland China and South Korea to Taiwan island, Germany, Australia, Singapore, and Indonesia, and it also circulated within east Asia. Our study is the first attempt to evaluate the evolutionary rates, timescales and migration dynamics of ORSV.

Enhanced proton conductivity of sulfonated poly(ether ether ketone) membranes at elevated temperature by incorporating (3-aminopropyl)triethoxysilane-grafted graphene oxide

Shuguo Qu,Chenchen Zhang,Minhui Li,Yan Zhang,Lunbo Chen,Yushuai Yang,Bo Kang,Yiwei Wang,Jihai Duan,Weiwen Wang 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.12

Making inexpensive proton exchange membrane with high proton conductivity for the proton exchange membrane fuel cell (PEMFC) is still a challenging problem. Graphene oxide (GO) nanoparticles grafted with (3-aminopropyl) triethoxy silane (APTES) were prepared and then incorporated into sulfonated poly(ether ether ketone) (SPEEK) matrix by solution casting to make the composite proton exchange membrane. The obtained nanoparticles and composite membranes were characterized by XRD, FT-IR, Raman, TGA, SEM, and UTM. GO treated with the silane coupling agent improved the dispersion stability and compatibility of GO in SPEEK, which decreased the agglomeration of GO nanoparticles in the SPEEK membrane. The prepared nanocomposite membranes exhibited better water retention properties and proton conductivity. The proton conductivity of the SPEEK membrane with 2wt% amine functionalized GO (AGO) reached 11.32mS/cm at 120oC, which was 2.45-times higher than that of the pristine SPEEK membrane. The reason was that AGO nanoparticles disperse uniformly in the SPEEK membranes, which provides new channels for proton transfer. The potential application of this composite membrane in the PEMFC was indicated.