A simple and novel method was developed to determine methylene blue（MB） by resonance light scattering（RLS） using silica nanoparticles（SiO2NPs） as the probe.It was found that MB could enhance the RLS intensity of...A simple and novel method was developed to determine methylene blue（MB） by resonance light scattering（RLS） using silica nanoparticles（SiO2NPs） as the probe.It was found that MB could enhance the RLS intensity of SiO2NPs.Moreover,the increase in RLS intensity was linear with the concentration of MB over the range of 0.01-3.0 μg mL^-1.The limit of detection（LOD） was as low as 4.36 ng mL^-1（3σ） and the relative standard deviation（RSD） was 2.4%（n=6）.Under the optimum experimental conditions,this proposed method was successfully applied for the determination of MB in aquaculture samples with recoveries between 96.3% and 107%.Possible mechanisms for the RLS enhancement of SiO2NPs in the presence of MB were also discussed.展开更多
We put forward effective methods of increasing the tensile strain of cementitious composites with 2% PVA fiber and high fly ash content. The test results show that curing condition has a significantly effect on the te...We put forward effective methods of increasing the tensile strain of cementitious composites with 2% PVA fiber and high fly ash content. The test results show that curing condition has a significantly effect on the tensile performance. It is approved that the specimens incorporated appropriate volume fraction rubber powder and lightweight aggregate greatly increase the tensile strain of composites at medium-term age, but indefinitely at long-term age. To a certain extent, EVA can limitedly enhance the tensile performance of comentitious composites owing to the formation of polymer membrane and the hindered hydration of cement.展开更多
This self repair system is based upon harmless ground borne bacteria as the self-healing agent.The bacteria are activated after the concrete is cracked and the bacterial spores are exposed to moisture and air.The bact...This self repair system is based upon harmless ground borne bacteria as the self-healing agent.The bacteria are activated after the concrete is cracked and the bacterial spores are exposed to moisture and air.The bacterial reproduction process creates a calcite by-product which fills the cracks in the concrete.By sealing the cracks in concrete,an effective barrier to air or liquid borne deleterious materials are formed and as a consequence of this,enhanced durability is achieved in the structure,result-ing in lower life cycle costs.The concrete/mortar prisms were cracked and tested for water flow.They were then left for 56 days to heal and were subject to a test for water tightness.Healing was observed and a reduced water flow(74%and 32%healed)measured with the healed samples when compared to the specimens that were cracked and subjected to a water flow test without any healing agent.The number of samples were limited and a larger scale test is recommended for further work;however,this is a proof of concept of the process of healing and testing.展开更多
文摘A simple and novel method was developed to determine methylene blue（MB） by resonance light scattering（RLS） using silica nanoparticles（SiO2NPs） as the probe.It was found that MB could enhance the RLS intensity of SiO2NPs.Moreover,the increase in RLS intensity was linear with the concentration of MB over the range of 0.01-3.0 μg mL^-1.The limit of detection（LOD） was as low as 4.36 ng mL^-1（3σ） and the relative standard deviation（RSD） was 2.4%（n=6）.Under the optimum experimental conditions,this proposed method was successfully applied for the determination of MB in aquaculture samples with recoveries between 96.3% and 107%.Possible mechanisms for the RLS enhancement of SiO2NPs in the presence of MB were also discussed.
基金Funded by National Basic Research Program of China (973 Program) (No. 2009CB623200)Hong Kong Research Grant Council under CERG 616405
文摘We put forward effective methods of increasing the tensile strain of cementitious composites with 2% PVA fiber and high fly ash content. The test results show that curing condition has a significantly effect on the tensile performance. It is approved that the specimens incorporated appropriate volume fraction rubber powder and lightweight aggregate greatly increase the tensile strain of composites at medium-term age, but indefinitely at long-term age. To a certain extent, EVA can limitedly enhance the tensile performance of comentitious composites owing to the formation of polymer membrane and the hindered hydration of cement.
文摘This self repair system is based upon harmless ground borne bacteria as the self-healing agent.The bacteria are activated after the concrete is cracked and the bacterial spores are exposed to moisture and air.The bacterial reproduction process creates a calcite by-product which fills the cracks in the concrete.By sealing the cracks in concrete,an effective barrier to air or liquid borne deleterious materials are formed and as a consequence of this,enhanced durability is achieved in the structure,result-ing in lower life cycle costs.The concrete/mortar prisms were cracked and tested for water flow.They were then left for 56 days to heal and were subject to a test for water tightness.Healing was observed and a reduced water flow(74%and 32%healed)measured with the healed samples when compared to the specimens that were cracked and subjected to a water flow test without any healing agent.The number of samples were limited and a larger scale test is recommended for further work;however,this is a proof of concept of the process of healing and testing.
