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Three different microstructures with line pattern, grid pattern, and spot pattern were fabricated on titanium surfaces by nanosecond laser. Scanning electron microscopy (SEM), contact angle measurement, surface roughness gage, and X-ray photoelectron spectroscopy (XPS) analyses were used to characterize and measure the surface morphology, contact angle, surface roughness, and chemical composition of titanium after laser processing. The results indicate that the contact angle of titanium surface is 77.8° immediately after laser processing, which shows hydrophilicity, and the contact angle presents a rising tendency with time in general. At steady state, the maximum contact angles for line pattern, grid pattern, and spot pattern increased to 157.2°, 153°, and 132.5°, respectively. It can be found that the surface wettability has changed from hydrophilicity to hydrophobicity and even to superhydrophobicity. The influence of surface morphology on the surface wettability effects immediately after laser treatment and does not change with time, while the effect of surface chemical composition on the surface wettability will continue from the beginning of laser processing to the stabilization of surface chemical composition. Finally, it can be deduced that the accumulation of carbon on the surface is probably the critical factor to improve the surface hydrophobicity. Therefore, it is concluded that laser-induced modification of surface wettability correlates with surface morphology and surface chemical composition. [ABSTRACT FROM AUTHOR]

In this work, the binding characteristics of methylene blue (MB) to human serum albumin (HSA) and the influence of Cu2+ and Fe3+ on the binding affinity ofMBto HSAwere investigated using fluorescence, absorption, circular dichroism(CD) spectroscopy andmolecular modelling. The results of competitive binding experiments using the site probes ketoprofen and ibuprofen as specific markers suggested that MB was located in site I within sub-domain IIA of HSA. The molecular modelling results agreed with the results of competitive site marker experiments and the results of CD spectra indicated that the interaction betweenMB and HSA caused the conformational changes in HSA. The binding affinity ofMB to HSAwas enhanced but to a different extent in the presence of Cu2+ and Fe3+, respectively, which indicated that the influence of different metal ions varied. Enhancement of the binding affinity of MB to HSA in the presence of Cu2+ is due to the formation of Cu2+-HSA complex leading to the conformational changes in HSA, whereas in the presence of Fe3+, enhancement of the binding affinity is due to the greater stability of the Fe3+-HSA-MB complex compared with the MB-HSA complex. [ABSTRACT FROM AUTHOR]

The pure γ-Ca 2SiO 4 (γ-C 2S) phase was prepared at 1623 K of calcining temperature, 10 h of holding time and furnace cooling. The β-C 2S phase was obtained through γ-C 2S conversion with the following calcination system which was adopted at 1473 K of calcining temperature, 1 h of holding time and then water-cooling. The conversion rate of γ-C 2S was studied by the Rietveld quantitative laboratory X-ray powder diffraction supported by synchrotron X-ray diffraction images. The refinement results show that the final conversion rate of γ-C 2S is higher than 92%. The absolute error of the γ-C 2S conversion rate between two Rietveld refinements (sample with or without α-Al 2O 3) is 3.6%, which shows that the Rietveld quantitative X-ray diffraction analysis is an appropriate and accurate method to quantify the γ-C 2S conversion rate. [ABSTRACT FROM AUTHOR]

This paper deals with the hydration of a blend of Portland cement and activated coal gangue in order to determine the relationship between the degree of hydration and compressive strength development. The hydration process was investigated by various means: isothermal calorimetry, thermal analysis, non-evaporable water measurement, and X-ray diffraction analysis. The results show that the activated coal gangue is a pozzolanic material that contributes to the hydration of the cement blend. The pozzolanic reaction occurs over a period of between 7 and 90 d, consuming portlandite and forming both crystal hydrates and ill-crystallized calcium silicate hydrates. These hydrates are similar to those found in pure Portland cement. The results show that if activated coal gangue is substituted for cement at up to 30% (w/w), it does not significantly affect the final compressive strength of the blend. A long-term compressive strength improvement can in fact be achieved by using activated coal gangue as a supplementary cementing material. The relationship between compressive strength and degree of hydration for both pure Portland cement and blended cement can be described with the same equation. However, the parameters are different since blended cement produces fewer calcium silicate hydrates than pure Portland cement at the same degree of hydration. [ABSTRACT FROM AUTHOR]

This paper describes the results of an investigation into the effect of the variation of curing temperatures between 0 and 60 °C on the hydration process, pore structure variation, and compressive strength development of activated coal gangue-cement blend (ACGC). Hardened ACGC pastes cured for hydration periods from 1 to 360 d were examined using the non-evaporable water method, thermal analysis, mercury intrusion porosimetry, and mechanical testing. To evaluate the specific effect of activated coal gangue (ACG) as a supplementary cementing material (SCM), a fly ash-cement blend (FAC) was used as a control. Results show that raising the curing temperature accelerates pozzolanic reactions involving the SCMs, increasing the degree of hydration of the cement blends, and hence increasing the rate of improvement in strength. The effect of curing temperature on FAC is greater than that on ACGC. The pore structure of the hardened cement paste is improved by increasing the curing temperature up to 40 °C, but when the curing temperature reaches 60 °C, the changing nature of the pore structure leads to a decrease in strength. The correlation between compressive strength and the degree of hydration and porosity is linear in nature. [ABSTRACT FROM AUTHOR]