Coupling reaction of carbon dioxide and epoxides efficiently catalyzed by one-component aluminum–salen complex under solvent-free conditions

Dawei Tian,Binyuan Liu,Li Zhang,Xiaoyang Wang,Wei Zhang,Lina Han,Dae Won Park 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.4

Four novel bifunctional aluminum–salen complexes (2a, 2b, 2c, and 2d) containing both Lewis acidic metal center and Lewis base quaternary phosphonium salt sites within one molecule and an aluminum–salen complex with a neutral tert-butyl group (2f) for comparison were synthesized and characterized by UV–vis, IR, 1H, 13C, 27Al NMR spectroscopy and Elemental analysis (EA). Their catalytic efficiencies as single-component catalysts toward the coupling reaction of carbon dioxide and propylene oxide were evaluated. These complexes exhibit catalytic activity in the order 2d > 2a > 2b > 2c 2f. 27Al NMR spectra reveal the existence of five- and six-coordinated metal centers in the aluminum–salen complexes bearing a quaternary phosphonium salt group, whereas only five-coordinate aluminum species were found in the aluminum–salen complex with a neutral tert-butyl group. This indicates the importance of the six-coordinate aluminum center in enhancing the catalytic activity as well as an intramolecular cooperative effect in bifunctional aluminum–salen complexes 2a–d. The effects of reaction variables on the catalytic performance were investigated in detail. These new catalysts are highly stable to moisture and air and robust to impurities in the coupling reaction.

Research on Energy Flow Optimization of Compound Storage System in Pure Electric Vehicle with Longitudinal Dynamics

Meng Dawei,Zhang Yu,Zhou Meilan,Tian Xiaochen 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.12

Aiming at short endurance mileage for electric vehicle, effected vehicle life because of battery excessive charging and discharging, the control method is put forward making use of super-capacitor to recovery regenerative braking energy, Hafei-Saibao electric vehicle is as example,seven kinds of topology with composite energy-single load are researched on power consumption, and the force condition of front and rear wheels is analyzed for front driving vehicle,the required energy of front wheel is detected to develop control strategy. On the basis of experimental data, co-simulation is achieved in the vehicle special simulation software, the experimental results show endurance mileage of improved car has increased by 34%, endurance mileage after being charged is 243 kilometer, the per hundred kilometers consumption has been decreased to 7.5 kW.h from 12 kW.h, the electrical consumption has been decreased by 37.5%, and the full load characteristics is optimized.

Development of a Novel 3-DOF Suspension Mechanism for Multi-Function Stylus Profiling Systems

Jia Tian,Yanling Tian,Zhiyong Guo,Fujun Wang,Dawei Zhang,Xianping Liu,Bijian Shirinzadeh 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.11

This paper proposes a novel 3-DOF suspension mechanism for multi-function stylus profiling systems. Incorporating an electromagnetic force actuator, the 3-DOF suspension mechanism provides a controlled loading force. For reasons of the thermal and mechanical stability, a triangular flexure structure is utilized to support the stylus. The stiffness matrix method is used to establish the analytical stiffness model of the 3-DOF suspension mechanism. Considering the 3-DOF suspension mechanism as a 3-DOF lumped-mass-spring system, the dynamic model is established. Finite element analysis (FEA) is used to validate the established static and dynamic models of the 3-DOF suspension mechanism. A prototype is fabricated and experimental tests are carried out to characterize the mechanism’s performance. The results show that the 3-DOF suspension mechanism provides a controlled force in a range of up to 10 mN and has a working range in excess of 10 μm with a first natural frequency of 342 Hz in Z axis, indicating good capability for multi-function measurements at the micro/nano scale.

Equilibrium, kinetic and mechanism studies on the biosorption of Cu2+ and Ni2+ by sulfur-modified bamboo powder

Tian Ai,Xiaojun Jiang,Hongmei Yu,Hong-Bo Xu,Dawei Pan,Qingyu Liu,Dongyu Chen,Jinyang Li 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.2

Two biosorbents were prepared using bamboo powder modified with mercaptoacetic acid and carbondisulfide, which exhibits strong adsorption properties for Cu2+ and Ni2+. The obtained materials were characterized byFTIR. Maximum adsorption for both metals was found to occur around pH 5.0-6.5. The kinetic data followed thepseudo-second-order model. The maximum adsorption capacities of Cu2+ and Ni2+ on mercaptoacetic acid modifiedbamboo powder determined from Langmuir isotherm were 103.97mg g−1 and 61.35mg g−1, respectively. While oncarbon disulfide modified bamboo powder were 128.21mg g−1 and 56.82mg g−1, respectively. The adsorption mechanismanalysis revealed that the most possible adsorption mode of Cu2+ was coordination, and Ni2+ was ion exchange. The obtained adsorbents could effectively remove Cu2+ and Ni2+ from industrial electroplating wastewater and could beused repeatedly for more than five cycles.

Torsional Properties of Boron Nitride Nanocones with Different Cone Heights, Disclination Angles and Simulation Temperatures

Yuan Li,Yanling Tian,Chengjuan Yang,Kunhai Cai,Dawei Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.7

The torsional properties of single-walled boron nitride (BN) nanocones at different cone heights, disclination angles and simulation temperatures have been investigated using molecular dynamics (MD) simulation. The simulation results indicate that the torque and average potential energy decrease with the increasing cone height and disclination angle, and the failure torsion angle increases with the increasing cone height and disclination angle. For different simulation temperatures, the torsional behavior of BN nanocones at higher simulation temperature is more serious and earlier to reach a failure point, the maximum torque and average potential energy of the system decrease with the increasing simulation temperature. For different loading rates, the failure torsion angle decreases with the increasing loading rate, so the fracture of BN nanocone occurred earlier with higher loading rate. Therefore, the cone height, disclination angle, simulation temperature and loading rate are considered to be four main influencing factors for the torsional properties of the BN nanocones.

Favorable Impact Toughness of High Heat Input Coarse-Grained HAZ in an Ultra-Low Carbon High-Strength Microalloyed Steel

Fuhui Cui,Junjie Wang1,Xiangdong Gan,Dawei Yu,Ilya Vladimirovich Okulov,Qinghua Tian,Xueyi Guo 대한금속ᆞ재료학회 2023 METALS AND MATERIALS International Vol.29 No.2

Liquid Mg is capable of quickly eroding the refractory Ni-based superalloy and selectively dissolve Ni, which opens up anew avenue for the recycling of superalloy scraps for comprehensive metal reclamation. This study aims at investigating theunderlining mechanism and kinetics of the selective dissolution of Ni from Inconel 718 (one type of Ni-based superalloy)with liquid Mg, by experimenting at 750, 800, and 850 °C for various amounts of time in an inert atmosphere. This selectivedissolution process is also known as liquid metal dealloying. Results show that a permeable dealloyed layer was formedresulting from the preferential dissolution of Ni over other metallic elements (e.g., Fe, Cr, Nb, Mo, and Ti). At the dealloyingforefront, the grain boundaries of the matrix γ phase were preferentially eroded by liquid Mg. The opposite concentrationgradients of Ni (4–9 wt%) and Mg (12–18 wt%) cross the dealloyed layer suggested their counter diffusion. A higher heatingtemperature substantially increased the dealloying rate.

Dealloying Superalloy by Liquid Mg for the Selective Extraction of Ni

Fuhui Cui,Junjie Wang,Xiangdong Gan,Dawei Yu,Ilya Vladimirovich Okulov,Qinghua Tian,Xueyi Guo 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.3

Liquid Mg is capable of quickly eroding the refractory Ni-based superalloy and selectively dissolve Ni, which opens up anew avenue for the recycling of superalloy scraps for comprehensive metal reclamation. This study aims at investigating theunderlining mechanism and kinetics of the selective dissolution of Ni from Inconel 718 (one type of Ni-based superalloy)with liquid Mg, by experimenting at 750, 800, and 850 °C for various amounts of time in an inert atmosphere. This selectivedissolution process is also known as liquid metal dealloying. Results show that a permeable dealloyed layer was formedresulting from the preferential dissolution of Ni over other metallic elements (e.g., Fe, Cr, Nb, Mo, and Ti). At the dealloyingforefront, the grain boundaries of the matrix γ phase were preferentially eroded by liquid Mg. The opposite concentrationgradients of Ni (4–9 wt%) and Mg (12–18 wt%) cross the dealloyed layer suggested their counter diffusion. A higher heatingtemperature substantially increased the dealloying rate.