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Dongzhi Zhang,Chen Ge,Jinjuan Xue,Tingshun Jiang,Longbao Yu,Yutang Shen,Hengbo Yin 한국공업화학회 2009 Journal of Industrial and Engineering Chemistry Vol.15 No.4
A series of Cu–Zn–Zr catalysts were prepared by a coprecipitation method and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, temperature programmed reduction, and N2 adsorption. The catalytic activity of the Cu–Zn–Zr catalyst in the hydrogenation of maleic anhydride using ethanol as a solvent was studied at 220–280℃ and 1 MPa. Maleic anhydride was mainly hydrogenated to gbutyrolactone and tetrahydrofuran while ethanol dehydrogenated to ethyl acetate. After reduction, CuO species present in the calcined Cu–Zn–Zr catalysts were converted to metallic copper (Cu0). The presence of ZrO2 favored the deep hydrogenation of g-butyrolactone to tetrahydrofuranwhile the presence of ZnO was beneficial to the formation of the intermediate product g-butyrolactone. The molar ratios of the hydrogen produced in ethanol dehydrogenation to the hydrogen consumed in maleic anhydride hydrogenation increased with the increase of the reaction temperature.
Stability-based On-demand Multi-path Distance Vector Protocol for Edge Internet of Things
Dongzhi Cao,Peng Liang,Tongjuan Wu,Shiqiang Zhang,Zhenhu Ning 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.10
In edge computing scenarios, IoT end devices play a crucial role in relaying and forwarding data to significantly improve IoT network performance. However, traditional routing mechanisms are not applicable to this scenario due to differences in network size and environment. Therefore, it becomes crucial to establish an effective and reliable data transmission path to ensure secure communication between devices. In this paper, we propose a trusted path selection strategy that comprehensively considers multiple attributes, such as link stability and edge cooperation, and selects a stable and secure data transmission path based on the link life cycle, energy level, trust level, and authentication status. In addition, we propose the Stability-based On-demand Multipath Distance Vector (STAOMDV) protocol based on the Ad hoc AOMDV protocol. The STAOMDV protocol implements the collection and updating of link stability attributes during the route discovery and maintenance process. By integrating the STAOMDV protocol with the proposed path selection strategy, a dependable and efficient routing mechanism is established for IoT networks in edge computing scenarios. Simulation results validate that the proposed STAOMDV model achieves a balance in network energy consumption and extends the overall network lifespan.
Zhang, Xiuling,Xu, Weiwei,Duan, Dongzhi,Park, Dong-Wha,Di, Lanbo IEEE 2018 IEEE transactions on plasma science Vol.46 No.8
<P>Atmospheric pressure (AP) oxygen cold plasma was adopted to synthesize Au/TiO<SUB>2</SUB> catalysts with the assistance of a simple modified incipient wetness impregnation process. Discharge voltages of 25.0, 29.0, and 35.0 kV and discharge time of 1, 2, and 4 min are selected to investigate the effects of discharge voltage and discharge time on the property of the Au/TiO<SUB>2</SUB> catalysts. The results of carbon monoxide (CO) oxidation activity testing show that AP oxygen cold plasma is beneficial to enhance the activity of the Au/TiO<SUB>2</SUB> catalysts, and the optimal discharge voltage and time are 29.0 kV and 1 min, respectively. CO conversion of the Au/TiO<SUB>2</SUB>-29-1 catalyst at 30 °C is 1.42 times as that of the Au/TiO<SUB>2</SUB>-As catalyst without plasma treatment. The UV-Vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy characterizations indicate that AP oxygen cold plasma not only can decompose the gold species formed by the modified impregnation process to form metallic gold species but also can remove some of the oxygen species on the surface of the TiO<SUB>2</SUB> support. The discharge time of 1 min at 29.0 kV is enough to decompose the gold species formed by the modified impregnation process, and to keep much active hydroxyl groups. Moreover, there is little difference in the size of gold nanoparticles in the Au/TiO<SUB>2</SUB> catalysts. Therefore, Au/TiO<SUB>2</SUB>-29-1 catalyst exhibits higher CO oxidation activity than Au/TiO<SUB>2</SUB>-As, and 1 min is the optimal discharge time. Thanks to the AP oxygen cold plasma method, high-performance Au/TiO<SUB>2</SUB> catalysts can be synthesized simply in a short time.</P>
A Heterogeneous IoT Node Authentication Scheme Based on Hybrid Blockchain and Trust Value
( Shiqiang Zhang ),( Yang Cao ),( Zhenhu Ning ),( Fei Xue ),( Dongzhi Cao ),( Yongli Yang ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.9
Node identity authentication is an essential means to ensure the security of the Internet of Things. Existing blockchain-based IoT node authentication schemes have many problems. A heterogeneous IoT node authentication scheme based on an improved hybrid blockchain is proposed. Firstly, the hybrid blockchain model is designed to make the blockchain and IoT environment more compatible. Then the proxy node selection mechanism is intended to establish a bridge between the ordinary IoT node and the blockchain, building by calculating the trust value between nodes. Finally, based on the improved hybrid blockchain, the node authentication scheme of the model and proxy node selection mechanism establishes a secure connection for communication between nodes. Safety and performance analysis shows proper safety and performance.
( Yuguo Dong ),( Jian Zhang ),( Rui Xu ),( Xinxin Lv ),( Lihua Wang ),( Aiyou Sun ),( Dongzhi Wei ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.11
Mycophenolic acid (MPA) is an antibiotic produced by Penicillium brevicompactum. MPA has antifungal, antineoplastic, and immunosuppressive functions, among others. β-Hydroxy-β-methylglutaryl-CoA (HMG-CoA) lyase is a key enzyme in the bypass metabolic pathway. The inhibitory activity of HMG-CoA lyase increases the MPA biosynthetic flux by reducing the generation of by-products. In this study, we cloned the P. brevicompactum HMG-CoA lyase gene using the thermal asymmetric interlaced polymerase chain reaction and gene walking technology. Agrobacterium tumefaciens-mediated transformation (ATMT) was used to insert a mutated HMG-CoA lyase gene into P. brevicompactum. Successful insertion of the HMG-CoA lyase gene was confirmed by hygromycin screening, PCR, Southern blot analysis, and enzyme content assay. The maximum MPA production by transformants was 2.94 g/l. This was 71% higher than wild-type ATCC 16024. Our results demonstrate that ATMT may be an alternative practical genetic tool for directional transformation of P. brevicompactum.
Qisi Lin,Ling Zhang,Dongzhi Yang,Zhao Chunjie 한국식품영양과학회 2014 Journal of medicinal food Vol.17 No.6
This study describes the characterization of essential oil and phenolic compounds in Disporopsis pernyi (Hua) Diels. The essential oil was analyzed by gas chromatography-mass spectroscopy (GC-MS) and twelve volatile bioactive compounds of D. pernyi were identified. Polyphenols were identified by reverse-phase high-performance liquid chromatography (RP-HPLC) coupled to electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) and quantified by ultrahigh-performance liquid chromatography (UPLC). A total of 4 polyphenolic compounds found in extract were identified as rutin, luteolin, quercetin, and betulinic acid. All obtained extracts and the 4 polyphenolic compounds were evaluated for their antimicrobial and antioxidant properties. The results suggested that the phenolic compounds contributed significantly to the antioxidant and antimicrobial activities of the plant.
Oxidation of cyclopentene catalyzed by tungsten-substituted molybdophosphoric acids
Jinjuan Xue,Haixia Li,Dongzhi Zhang,Tingshun Jiang,Longbao Yu,Yutang Shen,Hengbo Yin 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.3
A series of Keggin type tungsten-substituted molybdophosphoric acids (H3PMo12−nWnO40·XH2O) were synthesized and characterized by ICP-AES, FT-IR, TG-DSC, and XRD. The tungsten substitution extent significantly affected their catalytic activity in the oxidation of cyclopentene and the selectivity of the resultant products. The tungsten-substituted molybdophosphoric acids with tungsten substitution numbers in a range of 3-6.8 exhibited high catalytic activity in the oxidation of cyclopentene. After reaction for 8 h, the conversion of cyclopentene was up to 97%; the oxidation products mainly consisted of glutaraldehyde, cis-1,2-cyclopentanediol and trans-1,2-cyclopentanediol with the yields of ca. 23%, 27%, and 45%, respectively.
Oxidation of cyclopentene catalyzed by phosphotungstic quaternary ammonium salt catalysts
Jinjuan Xue,Aili Wang,Jingbo Wang,Dongzhi Zhang,Weiguang Chen,Longbao Yu,Tingshun Jiang,Hengbo Yin 한국공업화학회 2010 Journal of Industrial and Engineering Chemistry Vol.16 No.2
A series of phosphotungstic quaternary ammonium salts, Q3 (PW12O40) and Q3(PW4O16) [Q = (C5H5)N+(C16H33), (C16H33)N+(CH3)3, (C4H9)4N+, and (CH3)4N+], were used as the catalysts in oxidation of cyclopentene. The catalysts [(C5H5)N(C16H33)]3(PW4O16) and [(C16H33)N(CH3)3]3(PW4O16) showed high catalytic activity in the selective oxidation of cyclopentene while using H2O2 (50%) as an oxidant and 2-propanol as a solvent. The oxidation products mainly consisted of glutaraldehyde, cis-1,2-cyclopentanediol and trans-1,2-cyclopentanediol. The above-mentioned two catalysts were dissolved completely in the reaction medium during the catalysis process and precipitated themselves from the reaction system after reaction, showing the characteristics of reaction-controlled phase-transfer catalysis. The types of quaternary ammonium cations and the phosphotungstic anions in phosphotungstic quaternary ammonium salts affected catalytic activity.