Fluid and Diffusion Limits for Bike Sharing Systems

Bike sharing systems have rapidly developed around the world, and they are served as a promising strategy to improve urban traffic congestion and to decrease polluting gas emissions. So far performance analysis of bike sharing systems always exists many difficulties and challenges under some more general factors. In this paper, a more general large-scale bike sharing system is discussed by means of heavy traffic approximation of multiclass closed queueing networks with non-exponential factors. Based on this, the fluid scaled equations and the diffusion scaled equations are established by means of the numbers of bikes both at the stations and on the roads, respectively. Furthermore, the scaling processes for the numbers of bikes both at the stations and on the roads are proved to converge in distribution to a semimartingale reflecting Brownian motion (SRBM) in a $N^{2}$-dimensional box, and also the fluid and diffusion limit theorems are obtained. Furthermore, performance analysis of the bike sharing system is provided. Thus the results and methodology of this paper provide new highlight in the study of more general large-scale bike sharing systems.Comment: 34 pages, 1 figure

Bond-slip model for FRP laminates externally bonded to concrete at elevated temperature

Author name used in this manuscript: Jian-Guo DaiAuthor name used in this manuscript: J.G. Teng2012-2013 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Effect of temperature variation on the full-range behavior of FRP-to-concrete bonded joints

Author name used in this manuscript: J.G. TengAuthor name used in this manuscript: Jian-Guo Dai2012-2013 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Finite element modeling of reinforced concrete beams exposed to fire

Author name used in this manuscript: Jian-Guo DaiAuthor name used in this manuscript: J. G. Teng2013-2014 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Three-dimensional meso-scale finite element modeling of bonded joints between a near-surface mounted FRP strip and concrete

Author name used in this publication: J. G. Teng2012-2013 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Antisense-induced suppression of taxoid 14β- hydroxylase gene expression in transgenic Taxus × media cells

The enzyme taxoid 14β-hydroxylase (14OH) directs a side-route of taxol pathway to 14β-hydroxy taxoids. Suppression of this side-route could increase the production of taxol. To suppress taxoid 14β- hydroxylase gene (14OH) expression in the Taxus × media TM3 cell line, antisense RNA inhibition approach was used in this study. Following the construction of an antisense RNA expression vector of 14OH from Taxus chinensis, the antisense 14OH cDNA (as14OH) was introduced into TM3 cells by Agrobacterium tumefaciens-mediated transformation. Southern blot analysis of hygromycin phosphotransferase gene (HYG) revealed that this selection gene was integrated successfully into the genome of Taxus × media cells. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that the 14OH mRNA level in transgenic cells dropped dramatically, suggesting that the expression of endogenous14OH gene was significantly suppressed by the exogenous as14OH gene. Correspondingly, the total yield of three major C-14 oxygenated taxoids (yunnanxane, taxuyunnanine C, sinenxan C) was markedly reduced in the silenced cell lines when compared with those of the nontransgenic controls. These results indicated that the antisense RNA strategy is a useful tool in suppressing the expression of genes in Taxus and this method could be used to silence other important genes that divert Taxol pathway to side-route metabolites.Key words: Taxus × media, taxoid 14β-hydroxylase, antisense, gene suppression

A comparative study of the buffeting properties of FRP and steel box girder cable-stayed bridges

2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Water absorption property of cracked concrete and effect of water repellent treatment

2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Co3O4 Nanocrystals on Graphene as a Synergistic Catalyst for Oxygen Reduction Reaction

Catalysts for oxygen reduction and evolution reactions are at the heart of key renewable energy technologies including fuel cells and water splitting. Despite tremendous efforts, developing oxygen electrode catalysts with high activity at low costs remains a grand challenge. Here, we report a hybrid material of Co3O4 nanocrystals grown on reduced graphene oxide (GO) as a high-performance bi-functional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). While Co3O4 or graphene oxide alone has little catalytic activity, their hybrid exhibits an unexpected, surprisingly high ORR activity that is further enhanced by nitrogen-doping of graphene. The Co3O4/N-doped graphene hybrid exhibits similar catalytic activity but superior stability to Pt in alkaline solutions. The same hybrid is also highly active for OER, making it a high performance non-precious metal based bi-catalyst for both ORR and OER. The unusual catalytic activity arises from synergetic chemical coupling effects between Co3O4 and graphene.Comment: published in Nature Material

Resonances in J/ψ→ϕπ+π−J/\psi \to \phi \pi ^+\pi ^- and ϕK+K−\phi K^+K^-

A partial wave analysis is presented of $J/\psi \to \phi \pi ^+\pi ^-$ and $\phi K^+K^-$ from a sample of 58M $J/\psi$ events in the BES II detector. The $f_0(980)$ is observed clearly in both sets of data, and parameters of the Flatt\' e formula are determined accurately: $M = 965 \pm 8$ (stat) $\pm 6$ (syst) MeV/c$^2$, $g_1 = 165 \pm 10 \pm 15$ MeV/c$^2$, $g_2/g_1 = 4.21 \pm 0.25 \pm 0.21$. The $\phi \pi \pi$ data also exhibit a strong $\pi \pi$ peak centred at $M = 1335$ MeV/c$^2$. It may be fitted with $f_2(1270)$ and a dominant $0^+$ signal made from $f_0(1370)$ interfering with a smaller $f_0(1500)$ component. There is evidence that the $f_0(1370)$ signal is resonant, from interference with $f_2(1270)$. There is also a state in $\pi \pi$ with $M = 1790 ^{+40}_{-30}$ MeV/c$^2$ and $\Gamma = 270 ^{+60}_{-30}$ MeV/c$^2$; spin 0 is preferred over spin 2. This state, $f_0(1790)$, is distinct from $f_0(1710)$. The $\phi K\bar K$ data contain a strong peak due to $f_2'(1525)$. A shoulder on its upper side may be fitted by interference between $f_0(1500)$ and $f_0(1710)$.Comment: 17 pages, 6 figures, 1 table. Submitted to Phys. Lett.