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Qianwen Ran,Hong Yan,Jiajia He,Ning Li,Yushun Lei 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8
Effect of 1 wt% TiO2@carbon nanotubes (TiO2@CNTs) and 1 wt% praseodymium (Pr) on the microhardness and corrosionproperties of AZ91 magnesium alloy were discussed. The microhardness test, electrochemistry test that AZ91 magnesiumalloy with 1 wt% TiO2@CNTs and 1 wt% Pr addition exhibits excellent microhardness (111 HV), low corrosion currentdensity (0.165 mA·cm−2), and low polarization resistance (537.15 Ω·cm2) compared with AZ91 magnesium alloy (89 HV,0.184 mA·cm−2, 261.06 Ω·cm2). After 1 wt% TiO2@CNTs and 1 wt% Pr added to AZ91, the average crystallite size wasreduced and microhardness was increased. Additionally, the Al11Pr3phase formed by the combination of Pr and Al transformedthe morphology of β-Mg17Al12 phase into weeny particles and decreased the volume fraction of β-Mg17Al12 phase. The reduction and refinement of cathode phase (β-Mg17Al12 phase) weakened the micro-galvanic corrosion and sloweddown the corrosion rate.
Highly efficient removal of three red dyes by adsorption onto Mg–Al-layered double hydroxide
Ran-ran Shan,Liang-guo Yan,Yan-ming Yang,Kun Yang,Shu-jun Yu,Hai-qin Yu,Bao-cun Zhu,Bin Du 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
The Mg–Al-CO3-LDH with Mg2+/Al3+ molar ratio of 2 was prepared via coprecipitation method atconstant pH of 9–10 and used to remove three red dyes by batch adsorption method. The results showedthe Mg–Al-LDH were well crystallized and can adsorb the red dyes effectively. The optimal adsorbentdosage and contact time were 1.0 g and 60 min, respectively. Adsorbed amount hardly changed whenpH < 10. The adsorption kinetics fit the pseudo-second order kinetic models well and isothermscorrespond to Langmuir model strictly. All the relevant mechanisms were studied and manifested asanion exchange and also electrostatic attraction for CR.
Sensory involvement in the SOD1-G93A mouse model of amyotrophic lateral sclerosis
Yan-Su Guo,Dong-Xia Wu,Hong-Ran Wu,Shu-Yu Wu,Cheng Yang,Bin Li,Hui Bu,Yue-sheng Zhang,Chun-Yan Li 생화학분자생물학회 2009 Experimental and molecular medicine Vol.41 No.3
A subset of patients of amyotrophic lateral sclerosis (ALS) present with mutation of Cu/Zn superoxide dismutase 1 (SOD1), and such mutants caused an ALSlike disorder when expressed in rodents. These findings implicated SOD1 in ALS pathogenesis and made the transgenic animals a widely used ALS model. However, previous studies of these animals have focused largely on motor neuron damage. We report herein that the spinal cords of mice expressing a human SOD1 mutant (hSOD1-G93A), besides showing typical destruction of motor neurons and axons, exhibit significant damage in the sensory system, including Wallerian-like degeneration in axons of dorsal root and dorsal funiculus, and mitochondrial damage in dorsal root ganglia neurons. Thus, hSOD1-G93A mutation causes both motor and sensory neuropathies, and as such the disease developed in the transgenic mice very closely resembles human ALS. A subset of patients of amyotrophic lateral sclerosis (ALS) present with mutation of Cu/Zn superoxide dismutase 1 (SOD1), and such mutants caused an ALSlike disorder when expressed in rodents. These findings implicated SOD1 in ALS pathogenesis and made the transgenic animals a widely used ALS model. However, previous studies of these animals have focused largely on motor neuron damage. We report herein that the spinal cords of mice expressing a human SOD1 mutant (hSOD1-G93A), besides showing typical destruction of motor neurons and axons, exhibit significant damage in the sensory system, including Wallerian-like degeneration in axons of dorsal root and dorsal funiculus, and mitochondrial damage in dorsal root ganglia neurons. Thus, hSOD1-G93A mutation causes both motor and sensory neuropathies, and as such the disease developed in the transgenic mice very closely resembles human ALS.
Xu Hai-Yan,Yang Yi Cai,Li Dong-Cai,Wu Ran Ran,Wang Ai-Guo,Sun Dao-Sheng,Zhang Feng-Jun,오원춘 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.3
Heavy metal ion pollution of water resources is becoming increasingly serious, and adsorption is one of the most effective strategies for removing heavy metal ions. In the paper, hydrated hydrogen sodium vanadium oxide (HNaV 6O164H2O) fi lm developed for heavy metal ion adsorption was prepared directly via a low-temperature liquid-phase deposition approach. The prepared film shows an interesting porous flower-like morphology and has large spacing ( d = 10.87 Å). The highest adsorption capacity of the obtained HNaV 6O164H2O fi lm for Pb 2+, Cu 2+, Cd 2+ and Mn 2+ is 513 mg/g (2565 mg/m 2), 430 mg/g (2150 mg/m 2), 134 mg/g (875 mg/m 2) and 175 mg/g (670 mg/m 2), respectively. The adsorption percentage of the sample decreased from 92.2 to 86.3% after 4 cycles. The adsorption process follows the Langmuir adsorption isotherm and the pseudo second-order dynamic model, indicating that heavy metal ion adsorption by the fi lm is a single molecular layer chemical adsorption. In combination with various characterizations and comparison tests of samples after adsorption, the adsorption mechanisms include surface electrostatic attraction, complexation, and cation exchange. The results indicate that the fi lm is a potential material to remove heavy metal ions from the aqueous solution.
Ran Zhao,Bowen Wang,Shuying Cao,Wenmei Huang,Quanguo Lu,Jianwu Yan 한국자기학회 2018 Journal of Magnetics Vol.23 No.2
In this paper, we fabricated novel magnetostrictive composites by embedding <110>-oriented Tb-Dy-Ho-Fe fibers in an epoxy matrix. The magnetostrictive and magnetic properties (magnetostriction, magnetization, piezomagnetic coefficient and relative permeability) of the proposed composites were measured, analyzed, and compared to those of Tb0.29Dy0.48Ho0.23Fe1.9 alloy and Tb0.3Dy0.7Fe₂ continuous-fiber/epoxy composites. Tb0.29Dy0.48Ho0.23Fe1.9 continuous-fiber/epoxy composites have a saturation magnetostriction (λs) of 840 ppm and saturation magnetization (Ms) of 0.75 T. Their piezomagnetic coefficient exhibits a maximum value (8.2 μm/kA) at 19 kA/m. These proposed composites exhibit a large magnetostriction in high magnetic fields (> 400 kA/m) and a large relative permeability in low magnetic fields (< 100 kA/m). This result indicates that the given composites perform better than the Tb0.29Dy0.48Ho0.23Fe1.9 alloy and Tb0.3Dy0.7Fe₂ fiber/epoxy composites. Thus, the composites with characteristics of high sensitivity and large magnetostriction can be used in the field of ultrasonic sensing.
The New Strategy of Object-Based Directional Query
Run-tao liu,Yan-ming Wang,Zhen-guo Zhao,Guang -Yue Tian 보안공학연구지원센터 2014 International Journal of Database Theory and Appli Vol.7 No.6
To increase directional query efficiency, based on the study of existing algorithms of directional query, new pruning rules for directional query were given, combined with the new index structure MB-tree. The rules exclude the MBRs outside the query area and output all leaf nodes in the MBRs inside the query area. Based on the orders defined in MB-tree, a new algorithm of directional query is given combining with MB-tree by using recursive method, and the new algorithm can reduce I/O cost effectively. Experiment showed that the new directional query algorithm reduces the number of visited nodes, decreases I/O cost, and improves the efficiency of directional query.
Molecule-based electrorheological material assembled using β-cyclodextrin as substrate
Yan-Li Shang,Yun-Ling Jia,Yun Ma,Jun-Ran Li,Shao-Hua Zhang,Ming-Xiu Li 한국유변학회 2010 Korea-Australia rheology journal Vol.22 No.1
Molecule-based electrorheological (ER) materials as a novel type of ER materials, the inclusion compound [H2(β-CD-A)-PTA] between p-toluenesulfonic acid (PTA, guest) and H2(β-CD-A) (host) that is dicarboxylic acid of β-cyclodextrin (β-CD) , and the rare earth (RE) complexes [(β-CD-A)-PTA]3RE2 (RE=La, Gd, Y)of H2(β-CD-A)-PTA, were synthesized. The ER performance and dielectric property of the materials were studied. Our results show that the molecule-based ER materials assembled using β-cyclodextrin as a substrate,especially the inclusion compound and its rare earth (RE) complexes exhibit clear ER effect. The inclusion PTA can markedly enhance the ER performance of H2(β-CD-A) material. The ER activity of the yttrium complex is the highest among these materials. The characteristic of the molecule in molecule-based ER materials is an important factor in influencing ER property.
Yan, Shi Run,Lee, Kyu Wan,Jun, Ki Won,Lee, Sang Bong,Choi, Myoung Jae,Hong, Ji Sook 한국화학공학회 1999 Korean Journal of Chemical Engineering Vol.16 No.3
The hydrogenation of CO₂ to hydrocarbons over a precipitated Fe-Cu-Al/K catalyst was studied in a slurry reactor for the first time. Reducibility of the catalyst and effect of reaction variables (temperature, pressure and H₂/CO₂ ratio of the feed gas) on the catalytic reaction performance were investigated. The reaction results indicated that the Fe-Cu-Al/K catalyst showed a good CO₂ hydrogenation performance at a relatively low temperature (533 K). With the increase of reaction temperature CO₂ conversion and olefin to paraffin (O/P) ratio in C₂-C₄ hydrocarbons as well as the selectivity to C₂-C₄ fraction increased, while CO and CH₄ selectivity showed a reverse trend. With the increase in reaction pressure, CO₂ conversion and the selectivity to hydrocarbons increased, while the CO selectivity and O/P ratio of C₂-C₄ hydrocarbons decreased. The investigation of H₂/CO₂ ratio revealed that CO₂ conversion and CH₄ selectivity increased while CO selectivity and O/P ratio of C₂-C₄ decreased with increasing H₂/CO₂ ratio.
An Improved Method of Maximum Power Point Tracking Strategy for Wind Power Conversion System
CHEN Ran,CHEN Jie,CHEN Jia-wei,CHEN Zhi-hui,GONG Chun-ying,YAN Yang-guang 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5
The turbine speed loop adjustment is the key link of the designing of the controller for the fixed pitch variable speed wind energy conversion systems (WECS). Because of the strong nonlinear, big inertia and mechanical damping characteristics, it’s difficult to designing the controller of the wind power systems. In this paper, a small signal model is present, and based on the analyzing; a wind turbine speed loop regulator is designed. Then, a method of tracking the peak power conversion system is proposed, which is independent of the turbine parameters and air density. At last, simulation system is built, and the results of the simulation experiments show that, the performance of the controller algorithm meet the requirements of the MPPT without wind measurement.