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The effect of counter-ions on the ion selectivity of potassium and sodium ions in nanopores.
Tang, Dai,Kim, Daejoong Pergamon Press 2014 Bio-medical materials and engineering Vol.24 No.1
<P>The ion selective transport plays an important role in the function of cell membranes, and promotes the application of artificial permeable membranes. This phenomenon has been studied in case for different diameters and functional groups of nanopores. In this work, we focus on the effect of anions on cation selectivity, in particular the influence of various halide ions on K+ and Na+ selectivity. We adopted molecular dynamics simulations with non-charged nanopores under constant temperature and uniform concentration. The results show K+-selectivity in the solution with Cl- and Na+-selectivity in the solution with Br- and I-. This selectivity, on the contrary, disappears in the solution with F-. We also investigate the change of the hydration shell of ions and cation-anion interactions between in the bulk region and in the nanopores, which could explain this selective phenomenon.</P>
Dai TANG,Daejoong KIM 한국산업응용수학회 2012 한국산업응용수학회 학술대회 논문집 Vol.7 No.2
The ability to filter and separate ions is important for a wide range of biological and industrial processes, however this can often be very challenging. This is especially the case for K? and Na? which carry the same charge and are of similar sizes. In order to investigate their separation, we have conducted molecular dynamics simulations of solution with Cl?, K? and Na?, and studied their preferential absorption into nanotubes. Our results show how Cl? plays a deciding role in the ability of Na? and K? to enter nano-scale pores, and results in a remarkable ability to selectively transport Na? and K? through the pore.
Magnetic Annealing Effects on the Properties of Multilayer BaTiO3/CoFe2O4 Thin Films
Y. Q. Dai,J. M. Dai,X. W. Tang,X. B. Zhu,J. Yang,Q. C. Liu,Y. P. Sun 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12
Multilayer BaTiO3/CoFe2O4 thin films are prepared via a chemical solution deposition methodwith and without magnetic annealing, respectively. The microstructural, magnetic, dielectric andferroelectric properties of the films’ are investigated. The dielectric constant, polarization andmagnetization of the multilayer thin films are improved with magnetic annealing. Moreover, forthe magnetic annealing films, the saturation magnetization measured with the measuring magneticfield vertical to the film surface is much higher than that measured with the field parallel to thefilm surface. These novel phenomena may be caused by the decrease in the clamping of the BaTiO3layer and the arrangement of the induced easy axis in the CoFe2O4 layer caused by the appliedannealing field.
Tang, Qing,Lee, Yongjin,Li, Dai-Ying,Choi, Woojun,Liu, C. W.,Lee, Dongil,Jiang, De-en American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.28
<P>Copper electrocatalysts can reduce CO2 to hydrocarbons at high overpotentials. However, a mechanistic understanding of CO2 reduction on nanostructured Cu catalysts has been lacking. Herein we show that the structurally precise ligand-protected Cu-hydride nanoclusters, such as Cu32H20L12 (L is a dithiophosphate ligand), offer unique selectivity for electrocatalytic CO2 reduction at low overpotentials. Our density functional theory (DFT) calculations predict that the presence of the negatively charged hydrides in the copper cluster plays a critical role in determining the selectivity of the reduction product, yielding HCOOH over CO with a lower overpotential. The HCOOH formation proceeds via the lattice-hydride mechanism: first, surface hydrides reduce CO2 to HCOOH product, and then the hydride vacancies are readily regenerated by the electrochemical proton reduction. DFT calculations further predict that hydrogen evolution is less competitive than HCOOH formation at the low overpotential. Confirming the predictions, electrochemical tests of CO2 reduction on the Cu32H20L12 cluster demonstrate that HCOOH is indeed the main product at low overpotential, while H-2 production dominates at higher overpotential. The unique selectivity afforded by the lattice-hydride mechanism opens the door for further fundamental and applied studies of electrocatalytic CO2 reduction by copper-hydride nanoclusters and other metal nanoclusters that contain hydrides.</P>
Study on Defects Edge Detection in Infrared Thermal Image Based on Ant Colony Algorithm
TANG Qingju,DAI Jingmin,LIU Chunsheng,LIU Yuanlin,REN Chunping 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.4
Edge extraction is an important part in the detection of infrared thermal images. Ant colony algorithm has the characteristics of high efficiency, high noise suppression, and comprehensive information of edge information. The basic principle of ant colony algorithm is analyzed. An ant colony optimization algorithm for image edge detection is established. And to have defective parts for analysis of infrared thermography The ant colony algorithm and the classical Canny operator are compared and analyzed. The experimental results show that the algorithm has high efficiency, comprehensive information and high computational efficiency.
Dynamic Performance Analysis of Capture and Separation Process for a Microsatellite Docking Device
DAI Ye,ZHANG Yuan,LI Wen-juan,TANG Wen-ming 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.3
Aiming at the problem of short lifetime and high cost in the on-orbit Servicing technology, a new type of automatic autonomous probe-cone docking mechanism used for microsatellite docking is proposed which can realize on-orbit special services. The structure of the mini docking mechanism is provided according to the design indices, and a virtual prototype model of the mini-type universal docking system is established by using MATLAB software. The dynamics modeling of the docking process is presented based on the virtual work principle. The simplified dynamic analysis model during the capture process is established. The dynamic characteristic analysis of the catching process is completed to research the influence of the key parameters, and the virtual prototype model of the docking device is established through ADAMS for further verifying the proposed design. The analysis shows that this mechanism has the good capacity of capture and separation process and energy absorption to reduce the impact during the docking process. And the simulation results meet the design demands of mini-type universal autonomous docking mechanism.
Dai, Jin,Tang, Kun,Xiao, Wei,Yu, Gan,Zeng, Jin,Li, Wei,Zhang, Ya-Qun,Xu, Hua,Chen, Zhi-Qiang,Ye, Zhang-Qun Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.8
Background: C-reactive protein (CRP), considered as a prototypical inflammatory cytokine, has been proposed to be involved in tumor progression through inflammation. Recent studies have indicated CRP as a progostic predictor for urological cancers, but the results remain controversial. Materials and Methods: A systematic search of Medline, Scopus and the Cochrane Library was performed to identify eligible studies published between Jan 1, 2001 and Sep 1, 2013. Outcomes of interest were collected from studies comparing overall survival (OS), cancer-specific survival (CSS) and relapse-free survival (RFS) in patients with elevated CRP levels and those having lower levels. Studies were pooled, and combined hazard ratio (HR) of CRP with its 95% confidence interval (CI) for survival were used for the effect size estimate. Results: A total of 43 studies (7,490 patients) were included in this meta-analysis (25 for RCC, 10 for UC, and 8 for PC). Our pooled results showed that elevated serum CRP level was associated with poor OS (HR: 1.26, 95%CI: 1.22-1.30) and RFS (HR: 1.38 95%CI: 1.29-1.47), respectively. For CSS the pooled HR (HR: 1.33, 95%CI: 1.28-1.39) for higher CRP expression could strongly predict poorer survival in urological cancers. Simultaneously, elevated serum CRP was also significantly associated with poor prognosis in the subgroup analysis. Conclusions: Our pooled results demonstrate that a high serum level of CRP as an inflammation biomarker denotes a poor prognosis of patients with urological cancers. Further large prospective studies should be performed to confirm whether CRP, as a biomarker of inflammation, has a prognostic role in urological cancer progression.
Tang, Lijun,Wu, Di,Hou, Shuhua,Wen, Xin,Dai, Xin Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.8
A carbazole-based Schiff base CB2 was synthesized and applied as a highly selective and sensitive fluorescent probe for $Cu^{2+}$ in $H_2O$-DMSO (8/2, v/v, pH = 7.4) solution. CB2 exhibits an excellent selectivity to $Cu^{2+}$ over other examined metal ions with a prominent fluorescence "turn-on" at 475 nm. CB2 and $Cu^{2+}$ forms a 1:2 binding ratio complex with detection limit of $9.5{\mu}M$. In addition, the $Cu^{2+}$ recognition process is hardly interfered by other examined metal ions.
A New Ferulic Acid Ester and Other Constituents from Dracocephalum peregrinum
Dai, Li-Min,Zhao, Chun-Chao,Jin, Hui-Zi,Tang, Jian,Shen, Yun-Heng,Li, Hui-Liang,Peng, Cai-Yon,Zhang, Wei-Dong 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.10
A new ferulic acid ester, 1'-methyl-2'-hydroxyethyl ferulate (1), together with methylcaffeate (2), 4-hydroxy cinnamic acid (3), ferulic acid (4), caffeic acid (5), diosmetin (6), luteolin (7), 5,3',4'-trihydroxy-3,7-dimethoxyflavone (8), eriodictyol (9), kaempferol (10), quercetin (11), acacetin-7-O-glcopyranoside (12), 4-($\beta$-glucopyranosyloxy) benzoic acid (13), luteolin-7-O-(6"-feruloyl) glucopyranoside (14), luteolin-7-O-glucopyranoside (15), kaempferide-3-O-rhamnopyranoside (16), quercitrin (17), kaempferol-3-O-glucopyranoside (18), prunasin (19), quercetin-7-O-glucopyranoside (20), quercetin-3-O-glucopyranoside (21), plantaginin (22), linarin (23), luteolin-7-O-rutinoside (24), and chlorogenic acid (25) were isolated from the aerial parts of Dacocephalum peregrinum. The structure of 1 was elucidated on the basis of spectroscopic and HR-ESI-MS analyses. In addition, compound 1 exhibited mild inhibitory effect on NO production in LPS-stimulated RAW264.7 cells.