Design and preparation of aluminum alloy with high thermal conductivity based on CALPHAD and first-principles calculation

To obtain the aluminum alloy with high thermal and mechanical properties,the effects of alloying elements and the second phases on the thermal conductivity of Al alloys were investigated by CALPHAD and first-principles calculation,respectively.The properties of the second phases,including Young's modulus,Poisson's ratio and minimum thermal conductivity,were systematically studied.Results show that the ranking order of the effects of the alloying elements on the thermal conductivity is Mg>Cu>Fe>Si,and for Al-12Si alloys,the mathematical model of the relationship between the alloying elements and the thermal conductivity can be expressed as λ=ax^(2)-bx+c when the second phase precipitates in the matrix.All kinds of ternary phases of Al-Fe-Si have higher deformation resistance,rigidity,theoretical hardness,Debye temperature and thermal conductivity than the other phases which possibly exist in the Al-12Si alloys.Based on the guidance of CALPHAD and first-principles calculation,the optimized chemical composition of Al alloy with high conductivity is Al-11.5Si-0.4Fe-0.2Mg(wt.%)with a thermal conductivity of 137.50 W·m^(-1)·K^(-1)and a hardness of 81.3 HBW.

Efficient polymer-mediated delivery system for thiocyclam: Nanometerization remarkably improves the bioactivity toward green peach aphids

The unscientific application of synthetic pesticides has brought various negative effects on the environment,hindering the sustainable development of agriculture.Nanoparticles can be applied as carriers to improve pesticide delivery,showing great potential in the development of pesticide formulation in recent years.Herein,a star polymer(SPc)was constructed as an efficient pesticide nanocarrier/adjuvant that could spontaneously assemble with thiocyclam or monosultap into a complex,through hydrophobic association and hydrogen bonding,respectively,with the pesticide-loading contents of 42.54%and 19.3%.This complexation reduced the particle sizes of thiocyclam from 543.54 to 52.74 nm for pure thiocyclam,and 3814.16 to 1185.89 nm for commercial preparation(cp)of thiocyclam.Interestingly,the introduction of SPc decreased the contact angles of both pure and cp thiocyclam on plant leaves,and increased the plant uptake of cp thiocyclam to 2.4–1.9 times of that without SPc.Meanwhile,the SPc could promote the bioactivity of pure/cp thiocyclam against green peach aphids through leaf dipping method and root application.For leaf dipping method,the 50%lethal concentration decreased from 0.532 to 0.221 g/L after the complexation of pure thiocyclam with SPc,and that decreased from 0.390 to 0.251 g/L for cp thiocyclam.SPc seems a promising adjuvant for nanometerization of both pure and cp insecticides,which is beneficial for improving the delivery efficiency and utilization rate of pesticides.