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RISS 인기검색어
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- 저자 : Bowei Chen (검색결과 4 건)
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Selective Synthesis of N,N-Bis(3-dimethylaminopropyl)amine over Pd/γ-Al2O3
Chenhui Lin,Bowei Wang,Haotian Guo,Ligong Chen,Xilong Yan 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.3
The synthesis of N,N-bis(3-dimethylaminopropyl)amine (BPA) from 3-(dimethylamino)-propionitrile (PN) and 3-(N,N-dimethylamino)propylamine (PA) over Pd/γ-Al2O3 in autoclaves was investigated. A series of Pd catalysts were prepared by different methods and characterized by XRD, TEM, and N2 adsorption–desorption. It was found that their activities were obviously affected by calcination temperature and reducing agent. Among them, the catalyst calcined at 500 °C and reduced with NaBH4 exhibited the best performance in this reaction. It was possibly attributed to the better dispersion of palladium particles on γ-Al2O3. Furthermore, reaction parameters were also optimized. Under optimal conditions (PN/PA molar radio 1:1, toluene as solvent), BPA was obtained in 87.9% yield with 95.6% conversion over the above catalyst. Meanwhile, split of PN was observed. A probable mechanism of retro-Michael reaction was also proposed.
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Water film covering characteristic on horizontal fuel rod under impinging cooling condition
Zhang Penghui,Wang Bowei,Chen Ronghua,Su G.H.,Tian Wenxi,Qiu Suizheng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.11
Jet impinging device is designed for decay heat removal on horizontal fuel rods in a low temperature heating reactor. An experimental system with a fuel rod simulator is established and experiments are performed to evaluate water film covering capacity, within 0.0287e0.0444 kg/ms mass flow rate, 0 e164.1 kW/m2 heating flux and 13.8e91.4C feeding water temperature. An effective method to obtain the film coverage rate by infrared equipment is proposed. Water film flowing patterns are recoded and the film coverage rates at different circumference angles are measured. It is found the film coverage rate decreases with heating flux during single-phase convection, while increases after onset of nucleate boiling. Besides, film coverage rate is found affected by Marangoni effect and film accelerating effect, and surface wetting is significantly facilitated by bubble behavior. Based on the observed phenomenon and physical mechanism, dry-out depth and initial dry-out rate are proposed to evaluate film covering potential on a heating surface. A model to predict film coverage rate is proposed based on the data. The findings would have reliable guide and important implications for further evaluation and design of decay heat removal system of new reactors, and could be helpful for passive containment cooling research.
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Zequn Zhang,Qijuan Dong,Zhibin Chen,Junsheng Wu,Jiuyang Xia,Kang Huang,Pengcheng Zuo,Wei Xue,Bowei Zhang 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.2
The influence of Co content on the microstructure and corrosion behavior of Al0.3CoxCrFeNi (x = 0.25, 0.5 and 1.0) highentropy alloys were investigated. The results indicated that the increased content of Co improve the corrosion resistanceof alloy, which can be attributed to the distinction of phase composition in alloys caused by different Co content. TheAl0.3CoxCrFeNi alloy shows a double-phase (FCC + BCC) structure for x = 0.25 and 0.5, and BCC phase consists of (Al,Ni)-rich B2 phase and (Cr, Fe, Co)-rich A2 phase. The increase of Co content induces the transformations of crystalstructuresfrom BCC to FCC, resulting in the decrease of BCC phase proportion. The Al0.3CoCrFeNi alloy exhibits thesingle FCC structure, and all elements tend to be homogeneously distributed. The difference in the potential of FCC andBCC phases indicates the BCC phase acts as anode resulting to localized corrosion, while B2 phase preferentially dissolvescompared to the A2 phase due to the lower potential. Therefore, the existence of selective corrosion is found in thealloys with double-phase, by contrast, the alloy with single FCC phase shows random pitting corrosion.
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Yan Wang,Yong Zhang,Xiaolin Liu,Sen Sun,Shiyi Qin,Jiaqi Huang,Bowei Chen 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.127 No.-
To obtain a green, low-cost and efficient adsorbent, polydopamine (PDA) and b-cyclodextrin (b-CD) wereadopted to modify coal fly ash (CFA) to prepare polydopamine/b-cyclodextrin/coal fly ash composite(PDA/b-CD/CFA). The successful introduction of PDA and b-CD was proved by FT-IR, XRD and XPS. Theuranium extraction efficiency on PDA/b-CD/CFA reached 95.6% (pH = 5.0, T = 298 K, C0 = 10 mg/L andm/V = 0.2 g/L) and the whole adsorption process was perfectly fitted by the Pseudo-second-order model(R2 = 0.999), illustrating that uranium was extracted via chemisorption. The correlation coefficient R2 ofLangmuir model was 0.999, which was higher than other models, meaning that uranium extractionbehavior on PDA/b-CD/CFA was uniform monolayer adsorption. The maximum extraction capacity of uraniumon PDA/b-CD/CFA calculated by Langmuir model was 537.6 mg/g, which was larger than most ofreported adsorbents, indicating that PDA/b-CD/CFA was a potential candidate for uranium extractionfrom water environment. Moreover, PDA/b-CD/CFA performed excellent uranium extraction propertieswith the existence of coexisting ions and the desorption efficiency of uranium by PDA/b-CD/CFA washigher to 95.8% at the fifth cycles, fully suggesting that PDA/b-CD/CFA possessed good selectivity andcycle stability. Characterization results demonstrated that uranium was immobilized on PDA/b-CD/CFAthrough chelation, complexing action, electrostatic interaction and hydrogen bonding.
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