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G. Shi,Z. Liu,H.Y. Ban,Y. Zhang,Y.J. Shi,Y.Q. Wang 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.12 No.1
Local buckling can be ignored for hot-rolled ordinary strength steel equal angle compression members, because the width-to-thickness ratios of the leg don’t exceed the limit value. With the development of steel structures, Q420 high strength steel angles with the nominal yield strength of 420 MPa have begun to be widely used in China. Because of the high strength, the limit value of the width-to-thickness ratio becomes smaller than that of ordinary steel strength, which causes that the width-to-thickness ratios of some hot-rolled steel angle sections exceed the limit value. Consequently, local buckling must be considered for 420 MPa steel equal angles under axial compression. The existing research on the local buckling of high strength steel members under axial compression is briefly summarized, and it shows that there is lack of study on the local buckling of high strength steel equal angles under axial compression. Aiming at the local buckling of high strength steel angles, this paper conducts an axial compression experiment of 420MPa high strength steel equal angles, including 15 stub columns. The test results are compared with the corresponding design methods in ANSI/AISC 360-05 and Eurocode 3. Then a finite element model is developed to analyze the local buckling behavior of high strength steel equal angles under axial compression, and validated by the test results. Followingthe validation, a finite element parametric study is conducted to study the influences of a range of parameters, and the analysis results are compared with the design strengths by ANSI/AISC 360-05 and Eurocode 3.
Q. Zhang,F. K. Shan,G. X. Liu,A. Liu,W. J. Lee,B. C. Shin 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.10
Amorphous indium-titanium-zinc-oxide (ITZO) thin-film transistors (TFTs) with various channelthicknesses were fabricated at room temperature by using pulsed laser deposition. The channellayer thickness (CLT) dependence of the TFTs was investigated. All the ITZO thin films wereamorphous, and the surface roughnesses decreased slightly first and then increased with increasingCLT. With increasing CLT from 35 to 140 nm, the on/off current ratio and the field-effect mobilityincreased, and the subthreshold swing decreased. The TFT with a CLT of 210 nm exhibited theworst performance, while the ITZO TFT with a CLT of 140 nm exhibited the best performancewith a subthreshold voltage of 2.86 V, a mobility of 53.9 cm2V−1s−1, a subthreshold swing of 0.29V/decade and an on/off current ratio of 109.
Mitigation of CO poisoning on functionalized Pt–TiN surfaces
Zhang, R. Q.,Kim, C.-E.,Yu, B.-D.,Stampfl, C.,Soon, A. The Royal Society of Chemistry 2013 Physical chemistry chemical physics Vol.15 No.44
<P>It has been previously reported that the system of single Pt atoms embedded in N-vacancy (<I>V</I><SUB>N</SUB>) sites on the TiN(100) surface (Pt–TiN) could be a promising catalyst for proton exchange membrane fuel cells (PEM FCs). The adsorption of molecules on Pt–TiN is an important step, when it is incorporated as the anode or cathode of PEM FCs. Utilizing first principles calculations based on density functional theory, systematic investigations are performed on the adsorption of several atomic and molecular species on the Pt–TiN system, as well as the co-adsorption of them. The favorable binding sites and adsorption energies of several molecular species, namely carbon dioxide (CO<SUB>2</SUB>), carbon monoxide (CO), oxygen (O<SUB>2</SUB>), hydrogen (H<SUB>2</SUB>), hydroxyl (OH), an oxygen atom (O), and a hydrogen atom (H), are explored. For each, the adsorption energy and preferred binding site are identified and the vibrational frequencies calculated. It is found that CO<SUB>2</SUB>, CO and H prefer the Pt top site while OH and O favorably adsorb on the Ti top site. When CO and OH are co-adsorbed on the Pt–TiN(100) surface, OH weakens the adsorption of CO. The weakening effect is enhanced by increasing the coverage of OH. A similar behavior occurs for H and OH co-adsorption on the Pt–TiN(100) surface. Because co-adsorption with OH and H species weakens the adsorption of CO on Pt–TiN, it is expected that the acid and base conditions in PEM FCs could mitigate CO poisoning on functionalized Pt–TiN surfaces.</P> <P>Graphic Abstract</P><P>A careful interplay of an unconventional metallic nitride support (<I>i.e.</I> TiN with N surface vacancies) and environment-dependent surface functional groups (<I>e.g.</I> OH, H) to chemically inhibit the unwanted poisoning effect of CO on TiN-supported single-atom Pt catalysts. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3cp53334d'> </P>
Zhang, X.,Shi, L.,Li, X.,Sheng, Q.,Yao, L.,Shen, D.,Lu, Z.R.,Zhou, H.M.,Park, Y.D.,Lee, J.,Zhang, Q. Society for Bioscience and Bioengineering, Japan ; 2014 Journal of bioscience and bioengineering Vol.117 No.6
Understanding the mechanism of inhibition of α-glucosidase (EC 3.2.1.20) is clinically important because of the involvement of this enzyme in type 2 diabetes mellitus. In this study, we conducted inhibition kinetics of α-glucosidase with Ca<SUP>2+</SUP> and 10-ns molecular dynamics simulations. We found that direct binding of Ca<SUP>2+</SUP> to the enzyme induced structural changes and inhibited enzyme activity. Ca<SUP>2+</SUP> inhibited α-glucosidase in a mixed-type reaction (K<SUB>i</SUB> = 27.0 +/- 2.0 mM) and directly induced the unfolding of α-glucosidase, which resulted in the exposure of hydrophobic residues. The simulations suggest that thirteen Ca<SUP>2+</SUP> ions may interact with α-glucosidase residues and that the Ca<SUP>2+</SUP> binding sites are associated with the structural changes in α-glucosidase. Our study provides insight into the mechanism of the Ca<SUP>2+</SUP>-induced structural changes in α-glucosidase and the inhibition of ligand binding. These results suggest that Ca<SUP>2+</SUP> could act as a potent inhibitor of α-glucosidase for the treatment of type 2 diabetes mellitus.