Strategies in boosting photosensitization for biomedical applications

Science China Chemistry -     

Nonlinear vibration effects on the fatigue life of fluid-conveying pipes composed of axially functionally graded materials

Nonlinear Dynamics - Fatigue is inevitable in pipes conveying fluid due to unwanted vibration. Internal resonance occurs in such pipes due to pre-pressure. For the first time, the effects of...     

An investigation of paddle wheel Cu2(μ2-O2CCH3)4 for gas molecule adsorptions

Metal organic frameworks (MOFs) have been well-known and extensively researched due to the high storage /good selectivity for gas molecules. Herein, the structures and electron paramagnetic resonance (EPR) spectra for dicopper paddle wheel MOF compound (Cu₂(µ₂-O₂CCH₃)₄ with various gas molecule are theoretically investigated by density functional theory (DFT) calculations. The adsorption energies and isotherms (including pure gas molecules and the mixed ones) are calculated for the gas molecules interacting with the unsaturated Cu₂(µ₂-O₂CCH₃)₄. Both quantities exhibit the roughly consistent orders (e.g. H₂S?>?NH₃?>?CO₂?>?CO?>?H₂O?>?N₂?>?NO?>?H₂ for isotherms and H₂S?>?NH₃?>?N₂?>?CO₂?>?NO?>?H₂O?>?H₂?>?CO for adsorption energies), possibly suggesting that this material may act as a potential adsorbent of these gas molecules. The catalytic property of Cu₂(µ₂-O₂CCH₃)₄ for oxidation of CO and NO into non-toxic molecules and splitting of H₂O into H₂ and O₂ in the solvent condition are uniformly discussed. Simulation of Grand Canonical Monte Carlo (GCMC) in MS 8.0 and calculations in Langmuir model reveal that Cu₂(µ₂-O₂CCH₃)₄ has good selectivity for CH₄ in natural gas (CH₄/CO₂/N₂) and SO₂ in fog (SO₂/NO/NO₂/H₂O/O₂), which would exhibit potential environmentally friendly applications.     

Overview of finite elements simulation of temperature profile to estimate properties of materials 3D-printed by laser powder-bed fusion

Laser powder bed fusion(LPBF),like many other additive manufacturing techniques,offers flexibility in design expected to become a disruption to the manufacturing industry.The current cost of LPBF process does not favor a try-anderror way of research,which makes modelling and simulation a field of superior importance in that area of engineering.In this work,various methods used to overcome challenges in modeling at different levels of approximation of LPBF process are reviewed.Recent efforts made towards a reliable and computationally effective model to simulate LPBF process using finite element(FE)codes are presented.A combination of ray-tracing technique,the solution of the radiation transfer equation and absorption measurements has been used to establish an analytical equation,which gives a more accurate approximation of laser energy deposition in powder-substrate configuration.When this new analytical energy deposition model is used in in FE simulation,with other physics carefully set,it enables us to get reliable cooling curves and melt track morphology that agree well with experimental observations.The use of more computationally effective approximation,without explicit topological changes,allows to simulate wider geometries and longer scanning time leading to many applications in real engineering world.Different applications are herein presented including:prediction of printing quality through the simulated overlapping of consecutive melt tracks,simulation of LPBF of a mixture of materials and estimation of martensite inclusion in printed steel.     

Optimal spectral phase control of femtosecond laser-induced up-conversion luminescence in Sm^3+:NaYF4 glass

The spectral phase of the femtosecond laser field is an important parameter that affects the up-conversion(UC)luminescence efficiency of dopant lanthanide ions.In this work,we report an experi-mental study on controlling the UC lmiiinescence efficiency in Sm^3+:NaYF4 glass by 800-nm femtosec-ond laser pulse shaping using spectral phase modulation.The optimal phase control strategy efficiently enhances or suppresses the UC luminescence intensity.Based on the laser-power dependence of the UC luminescence intensity and its comparison with the luminescence spectrum under direct 266-nm fem-tosecond lciser irradiation,we propose herein an excitation model combining non-resonant two-photon absorption with resonance-media ted three-photon absorption to explain the experimental observations.     

基于等效介质原理的宽角超材料吸波体的理论分析

目前,很少有文章就如何实现宽角度吸波材料进行详细的理论分析和设计指导,设计宽角度吸波材料仍然是一件很困难的事情.本文基于等效介质理论对带有反射地板的单层介质超材料吸波体进行较为详细的理论分析.从基础电磁理论出发,推导TE波(横电波,电场方向与入射面垂直的平面电磁波)和TM波(横磁波,磁场方向与入射面垂直的平面电磁波)照射下吸波体的反射系数,分析实现宽角度吸波效果所需的等效电磁参数,为宽角度超材料吸波体的设计提供了理论基础.此外,论文还理论分析了实现宽带宽角吸波等效电磁参数所要满足的条件,并做了计算检验.结果表明,当介质等效电磁参数按照特殊曲线随频率发生变化时,理论上能实现宽带宽角的吸波效果.     

Yolk‐Shell Porous Microspheres of Calcium Phosphate Prepared by Using Calcium L‐Lactate and Adenosine 5′‐Triphosphate Disodium Salt: Application in Protein/Drug Delivery

A facile and environmentally friendly approach has been developed to prepare yolk‐shell porous microspheres of calcium phosphate by using calcium L ‐lactate pentahydrate (CL) as the calcium source and adenosine 5′‐triphosphate disodium salt (ATP) as the phosphate source through the microwave‐assisted hydrothermal method. The effects of the concentration of CL, the microwave hydrothermal temperature, and the time on the morphology and crystal phase of the product are investigated. The possible formation mechanism of yolk‐shell porous microspheres of calcium phosphate is proposed. Hemoglobin from bovine red cells (Hb) and ibuprofen (IBU) are used to explore the application potential of yolk‐shell porous microspheres of calcium phosphate in protein/drug loading and delivery. The experimental results indicate that the as‐prepared yolk‐shell porous microspheres of calcium phosphate have relatively high protein/drug loading capacity, sustained protein/drug release, favorable pH‐responsive release behavior, and a high biocompatibility in the cytotoxicity test. Therefore, the yolk‐shell porous microspheres of calcium phosphate have promising applications in various biomedical fields such as protein/drug delivery.