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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.
Development of miniature bar-type structural fuses with cold formed bolted connections
Dongzhi Guan,Sen Yang,Liang-Jiu Jia,Zhengxing Guo 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.1
A novel all-steel miniature bar-type structural fuse (MBSF) with cold formed bolted connections is developed in this study, which consists of a central energy dissipation core cut from a smooth round bar, an external confining tube and nuts. Three types of cross sections for the central energy dissipation core, i.e., triple-cut, double-cut and single-cut cross sections, were studied. Totally 18 specimens were axially tested under either symmetric or asymmetric cyclic loading histories, where the parameters such as cut cross sectional area ratio, length of the yielding portion and cross sectional type were investigated. Numerical simulation of 2 representative specimens were also conducted. An analytical model to evaluate the bending failure at the elastic portion was proposed, and a design method to avoid this failure mode was also presented. The experimental results show that the proposed MBSFs exhibit satisfactory hysteretic performance under both the two cyclic loading histories. Average strain values of 8% and 4% are found to be respectively suitable for designing the new MBSFs as the ultimate strain under the symmetric and asymmetric cyclic loadings.
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.
Experimental Evaluation of Precast Concrete Beam-Column Connections with High-strength Steel Rebars
Dongzhi Guan,Zhengxing Guo,Cheng Jiang,Sen Yang,Hui Yang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.1
A novel precast concrete beam-column connection partially reinforced with high-strength steel rebars of a yield strength greater than 630 MPa was introduced to avoid reinforcement obstruction in connection zones. Reversed cyclic loadings were applied to fullscale specimens to evaluate their seismic performance. For the first precast specimen, high-strength steel rebars acted as bottom longitudinal bars of the beams. For the second precast specimen, high-strength steel rebars were used as both bottom longitudinal bars and embedded bars that were anchored into the joint. The results show that the new precast connection exhibits a satisfactory seismic resistance. The anchored embedded bars are not necessary in the new system for a limited improvement in the structural performance. The mechanical equilibrium of the rectangular stress block method can be applied to estimate the strength of the new connection using the design philosophy of strong column-weak beam.
Jianbing Yang,Kefeng Ni,Dongzhi Wei,Yuhong Ren 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.5
Ni2+-functionalized Fe3O4@polydopamine magnetic nanoparticles (Ni2+-PD-MNPs) were designed and synthesized by in situ coating of magnetic nanoparticles with polydopamine, followed by conjugation of Ni2+ to the polydopamine film. The Ni2+-PD-MNPs were used to purify His-tagged red fluorescent protein (His-RFP) via affinity interaction between Ni2+ and the His-tag. The results showed that the Ni2+-PD-MNPs had extraordinary selectivity for His-RFP purification. In addition, a Histagged transaminase (ω-transaminase BJ110) was selectively immobilized onto the Ni2+-PD-MNPs without purification, and the immobilized enzyme showed improved specific activity, as well as enhanced stability and reusability.
Xuejun, Cao,Jianhang, Zhu,Dongzhi, Wei,Hur, Byong Ki 한국공업화학회 2002 Journal of Industrial and Engineering Chemistry Vol.8 No.3
Partition behavior of cephalexin and 7-ADCA in PEG-salts and EOPO-salts aqueous two-phase systems has been investigated under various different conditions. Effect of polymer molecular weight, salts types, tie line length on partition coefficients of cephalexin and 7-ADCA were described. Additives such as salts, water miscible solvents and surfactants were used to improve partition of cephalexin and 7-ADCA. NaSCN shows greatest influence on partition of cephalexin and 7-ADCA in 20% PEG 400-17.5% (NH_4)_2SO_4. Cephalexin and 7-ADCA partition coefficients reached 12.92 and 2.58, respectively. While NaCI shows greatest influence on partition of cephalexin and 7-ADCA in E0_40PO_60-(NH_4)_2SO_4. In 15% E0_40P0_60-13% (NH_4)_2SO_4 ATPS, partition coefficients of cephalexin and 7-ADCA reached 0.08 and 0.42, respectively. Cephalexin and 7-ADCA shows different partition trend in PEG-(NH_4)_2SO_4 and EOPO-(NH_4)_2SO_4 ATPS. In EOPO-(NH_4)_2SO_4 ATPS, diagrams of PEG3000-(NH_4)_2SO_4, E0_40PO_60-(NH_4)_2SO_4, E0_20PO_80-(NH_4)_2SO_4 were prepared and their differences were analyzed, and recovery of E0_40PO_60-(NH_4)_2SO_4 ATPS was performed with yield of 90-95%.
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.
Ma Xingyuan,Zheng Wenyun,Wang Tianwen,Wei Dongzhi,Ma Yushu The Microbiological Society of Korea 2006 The journal of microbiology Vol.44 No.3
The Escherichia coli heat-labile enterotoxin B subunit (HLT-B) is one of the most powerful mucosal immunogens and known mucosal adjuvants. However, the induction of high levels of HLT-B expression in E. coli has proven a difficult proposition. Therefore, in this study, the HLT-B gene was cloned from pathogenic E. coli and expressed as a fusion protein with GST (glutathion S-transferase) in E. coli BL2l (DE3), in an attempt to harvest a large quantity of soluble HLT-B. The culture conditions, including the culture media used, temperature, pH and the presence of lactose as an inducer, were all optimized in order to obtain an increase in the expression of soluble GST-rHLT-B. The biological activity of the purified rHLT-B was assayed in a series of GMI-ELISA experiments. The findings of these trials indicated that the yield of soluble recombinant GST-rHLT-B could be increased by up to 3-fold, as compared with that seen prior to the optimization, and that lactose was a more efficient alternative inducer than IPTG. The production of rHLT-B, at 92 % purity, reached an optimal level of 96 mg/l in a 3.7 L fermentor. The specific GM1 binding ability of the purified rHLT-B was determined to be almost identical to that of standard CTB.