Grazing activity increases decomposition of yak dung and litter in an alpine meadow on the Qinghai-Tibet plateau

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The effect of resin matrix composition on mechanical properties of e-glass fiber-reinforced composite for dental use

The effects of resin matrix composition including bis-phenol-A-diglycidyl dimethacrylate (bis-GMA)-methyl methacrylate (MMA) based or urethane dimethacrylate (UEDMA)-triethylene glycol dimethacrylate (TEGDMA) based composition and storage conditions on the mechanical properties of E-glass fiber-reinforced composites (FRCs) were studied. Three experimental groups ('Exper 1', 'Exper 2', 'Exper 3') with differing UEDMA to TEGDMA ratio in the matrix together with a control group ('Control') based on bis-GMA-MMA resin matrix were prepared by light-curing. The storage conditions for each group were dry storage at room temperature for 24 h and 30- and 60-day immersion in deionized (DI) water at 37°C, which further divided each group into three subgroups. For all the four composition groups, mechanical properties including hardness, flexural strength and modulus in both three-point and four-point bendings were tested (n = 6), together with water sorption and solubility study (n = 6) and fracture site scanning with a scanning electron microscope (SEM). The experimental specimens were relatively strong and stiff in three-point bending compared to previous research. The same specimens in three-point bending had a lower flexural modulus and fractured at higher flexural stress than in four-point bending. According to the SEM images after fracture, some resin matrix was still bound to the fiber surface, showing cohesive-interfacial fracture type and relatively stable matrix-fiber adhesion. According to comprehensive analysis, the control group showed superior mechanical performance in most of the tests.postprin

Four-dimensional visualization of construction scheduling and site utilization

Author name used in this publication: K. W. Chau2003-2004 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Implementation of visualization as planning and scheduling tool in construction

Author name used in this publication: K. W. Chau2002-2003 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

4D dynamic construction management and visualization software : 1. Development

Author name used in this publication: K. W. Chau2004-2005 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

The effect of water on the post-spinel transition and evidence for extreme water contents at the bottom of the transition zone

The transition of ringwoodite to bridgmanite and periclase (the post-spinel transition) is a strong control on the 660 phase discontinuity and the boundary between the transition zone and the lower mantle. The transition zone may contain significant amounts of water and thus the effect of water on the post-spinel transition must be known to correctly determine its properties. In this paper we examine the transition of ringwoodite to bridgmanite and periclase in both dry and wet conditions using density functional theory (DFT). In the dry case we calculate a high negative Clapeyron slope ( MPa/K at 1873 K). We also find that the Clapeyron slope is significantly nonlinear with temperature and much lower at 1000 K (−1.31 MPa/K) or if determined by linear interpolation from 1000 K (−2.37 MPa/K). The addition of water causes a large broadening of the transition through the development of a phase loop. Seismic studies suggest that the 660 km discontinuity is narrower than 2 km. For this to be the case our results suggest that the water content at the bottom of the transition zone needs to be either less than ∼700 ppm or, alternatively, above ∼8000 ppm (assuming an effective transition width near the maximum transition width). In the latter case this is above the saturation limit for bridgmanite and so will be accompanied by the production of a free water phase/hydrous melt. The hydration of ringwoodite also causes the onset of the transition to deepen with 1 wt% water increasing the depth of the transition by about 8 km. This is relatively small compared to seismically observed variations in the 660 km discontinuity of around 35 km and so water alone cannot account for the observed 660 km discontinuity topography. Water causes no substantial changes to the Clapeyron slope of the transition, so the 660 km topography could be explained by thermal variations of ∼500 K

Electrocatalytic Activity of Electropolymerized Cobalt Tetraaminophthalocyanine Film Modified Electrode towards 6-Mercaptopurine and 2-Mercaptobenzimidazole

The electrocatalytic activity of electropolymerized cobalt tetraaminophthalocyanine (poly-CoTAPc) film modified on the glassy carbon electrode (GCE) towards 6-mercaptopurine (6MP) and 2-Mercaptobenzimidazole (MBI) was studied. Comparing with the case at the unmodified GCE, the poly-CoTAPc film decreased the overpotential of oxidation of 6MP (1.0 × 10–3 mol L–1) and MBI (1.0×10–3 mol L–1) by 335 and 189mV, respectively, and increased the peak current by about 3 and 2 times, respectively, while the reduction potential of the disulphide product of previous oxidation of 6MP shifted positively by 312 mV and the peak current increased by 40 times in 0.1 mol L–1 phosphate buffer solution (PBS, pH = 2.0). The poly-CoTAPc film exhibited efficiently electrocatalytic activity for 6MP and MBI with relatively high sensitivity, stability and long-life.Keywords: Electrocatalysis, 6-mercaptopurine, 2-mercaptobenzimidazole, Cobalt Tetraaminophthalocyanine, Electropolymeric Fil

Single Spin Asymmetry in Lepton Angular Distribution of Drell-Yan Processes

We study the single spin asymmetry in the lepton angular distribution of Drell-Yan processes in the frame work of collinear factorization. The asymmetry has been studied in the past and different results have been obtained. In our study we take an approach different than that used in the existing study. We explicitly calculate the transverse-spin dependent part of the differential cross-section with suitable parton states. Because the spin is transverse, one has to take multi-parton states for the purpose. Our result agrees with one of the existing results. A possible reason for the disagreement with others is discussed.Comment: Typos corrected. Conclusions unchange

Identification of the orphan gene Prod 1 in basal and other salamander families.

The urodele amphibians (salamanders) are the only adult tetrapods able to regenerate the limb. It is unclear if this is an ancestral property that is retained in salamanders but lost in other tetrapods or if it evolved in salamanders. The three-finger protein Prod 1 is implicated in the mechanism of newt limb regeneration, and no orthologs have been found in other vertebrates, thus providing evidence for the second viewpoint. It has also been suggested that this protein could play a role in salamander-specific aspects of limb development. There are ten families of extant salamanders, and Prod 1 has only been identified in two of them to date. It is important to determine if it is present in other families and, particularly, the basal group of two families which diverged approximately 200 MYA