Deep understanding of the fluorescence quenching mechanisms of probes plays a crucial role in developing their practical *** fluorescence quenching mechanism of hydrazine-based fluorescence probes needs to be clarifie...
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Deep understanding of the fluorescence quenching mechanisms of probes plays a crucial role in developing their practical *** fluorescence quenching mechanism of hydrazine-based fluorescence probes needs to be clarified up to the ***,we designed and synthesized a new hydrazine-based fluorescence probe(HA-Na)based on the naphthalimide *** clarified the molecular origin of the non-fluorescence of this probe with the aid of computational chemistry and spectroscopic *** showed that the significant rotation of the hydrazine group in the excited state potential energy surface,which caused the complete charge separation,was responsible for the fluorescence quenching of the probe in an organic *** the rotation was prevented in an aggregative state or high-viscosity solution,the fluorescence of the probe *** other words,the fluorescence quenching mechanism of hydrazine-based fluorescence probes was attributed to the formation of a twisted intramolecular charge transfer(TICT)*** importantly,we demonstrated that this fluorescence molecular rotor could be used to monitor the autophagy process in living cells by detecting lysosomal viscosity changes during ***,this work provides an essential theoretical basis for the developing potential hydrazine-based fluorescence molecular rotors.
The previous neglect of shale oil multi-component characteristics and the nanpore wall properties of real shale result in an insufficient understanding of shale oil flow mechanisms in nanopores . Meanwhile, research o...
The previous neglect of shale oil multi-component characteristics and the nanpore wall properties of real shale result in an insufficient understanding of shale oil flow mechanisms in nanopores . Meanwhile, research on the flow regimes of shale oil remains lacking. In this study, molecular dynamics simulations are employed to investigate the flow of shale oil in hydroxylated quartz nanopores and rough kerogen nanopores. Simulation results show that the flow regime changed as the pressure gradient (∇ p ) increased to a critical value (∇ p c ). The velocity profile was parabolic when ∇ p < ∇ p c , but gradually became piston-like when ∇ p ≥ ∇ p c . Because increasing ∇ p leads the adsorbed molecules desorbing, aggregating in the pore center, and forming clusters that are not easy to shear. Increasing vertical force from pore wall causes fluid aggregation in the pore center as ∇ p increases. The ∇ p c in kerogen nanopores is larger than that in quartz nanopores due to the rough kerogen surface and sticky layers. Multi-component fluids have higher ∇ p c than single-component fluids in quartz nanopores. However, they have the same ∇ p c in kerogen nanopores due to the rough kerogen surface. This investigation can provide theoretical basis for high-efficient production of shale oil.
ABSTRACTABSTRACTA Ti3C2MXene/Ti composite powder was developed through surface modification and powder coating for producing a high-performance titanium matrix composites (TMCs) by laser power bed fusion. Introducing ...
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ABSTRACTABSTRACTA Ti3C2MXene/Ti composite powder was developed through surface modification and powder coating for producing a high-performance titanium matrix composites (TMCs) by laser power bed fusion. Introducing MXene rarely changed the original sphericity and flowability of Ti powder while it slightly enhanced the laser absorption capacity of Ti powder. The printing conditions in turn affected the morphology and distribution of MXene in as-printed composites. At optimised printing parameters, majority of MXene with high structural integrity and uniform distribution remained along the grain boundaries of as-printed composites, and a combination of high surface quality, geometrical accuracy and densification was obtained. The remaining MXene played the synergy of pulling-out effect and load transfer role, which increased the yield strength from 530 to 710 MPa, while retaining good ductility (elongation of 19.8%). Compared with ASTM standard cast Ti64 alloy, our MXene/Ti composites also exhibited superior comprehensive tensile properties and excellent strength-ductility synergy.
This paper presents a comprehensive analysis of the water vaporization in a hot water boiler system. The Computational Fluid Dynamics (CFD) technology was adopted to simulate the transient water evaporation in the boi...
This paper presents a comprehensive analysis of the water vaporization in a hot water boiler system. The Computational Fluid Dynamics (CFD) technology was adopted to simulate the transient water evaporation in the boiler termed as DZL14-1.25/115/70-AⅡ under the assumption of extreme conditions such as the water pump failure. The results indicated that the average pressure in the pipeline increased from 0.57Mpa to 0.66Mpa (the setting pressure of the safety valve) within 1050s. The pressure increased rapidly with the time increase. The average temperature of hot water changed linearly with time, and the internal thermal deviation of the hot water pipeline in the boiler decreased with time. The internal vaporization phenomenon of the hot water boiler became significant under the extreme condition. The steam flowed upward and accumulated in the upper part of the boiler shell. At 1050s, the vapor volume fraction in the hot boiler was 1.05%, which indicated that the safety valve above the stream shell need to be opened in time after 1050s to ensure the safety of the boiler.
Correction for ‘Efficient transformation of CO2 to cyclic carbonates using bifunctional protic ionic liquids under mild conditions’ by Xianglei Meng et al., Green Chem., 2019, 21, 3456–3463, DOI: 10.1039/C9GC01165J.
Correction for ‘Efficient transformation of CO2 to cyclic carbonates using bifunctional protic ionic liquids under mild conditions’ by Xianglei Meng et al., Green Chem., 2019, 21, 3456–3463, DOI: 10.1039/C9GC01165J.
Microalgae have great potential in producing energy-dense and valuable products via thermochemical processes. Therefore, producing alternative bio-oil to fossil fuel from microalgae has rapidly gained popularity due t...
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Hollow multi-shelled structures (HoMS), a new family of hierarchical nano/micro-structured materials, have evoked intensive studies to discover their unique temporal-spatial ordering features. The theoretical understa...
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Hollow multi-shelled structures (HoMS), a new family of hierarchical nano/micro-structured materials, have evoked intensive studies to discover their unique temporal-spatial ordering features. The theoretical understanding of the general synthetic methods of HoMS, i.e. the sequential templating approach (STA), makes it possible to understand, predict, and control the shell formation process. Herein, a mathematical model is established based on the experiment results, which reveal the appearance of concentration waves in the STA. The numerical simulation results not only correspond well to the experimental observations but also explain the regulation methods. Whereby, the underlying physical essence of STA is elucidated, suggesting that HoMS is the concrete representation of the concentration waves. Thereafter the formation of HoMS is not limited to the solid-gas reactions through high-temperature calcination, but could be extended to solution systems under low-temperature conditions.
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