Helium bubbles nucleation and growth in metals or metal tritide is a long-standing problem attracting considerable attention in nuclear industry but the mechanism remains indistinct and predicting the growth rate of helium bubble is inexistence still
up to new. Here, the rate of helium bubbles nucleation and growth in metal tritide is developed based on a dynamical model, which describes the diameter of helium bubbles increasing linearly as t**(1/3) in titanium tritide at room temperature, agreeing quite well with the experimental phenomenon. The way of reducing storage temperature from 300 to 225 K or increasing the helium atoms diffusion barrier from 0.81 to 1.1 eV can effectively restrain bubbles growth and prolong lifetime of titanium tritide more than 4 times, which provides a useful reference to relevant experiment exploration and applications. This model also can be used to predict lifetime of new tritium-storage materials and plasma facing materials in nuclear industry.
We propose a scheme for realizing the continuously tunable spectrum based on monatomic carbon chains. By hybrid density functional calculations, we first show that the direct band gap of monatomic carbon chains change continuously from 1.58 to 3.8 eV
as strain is applied from -5 to 10% to the chain, with separated Van Hove singularity peaks enhanced. To realize this tunability, a realistic stretching device is proposed by contacting the chain with graphene sheets, which can apply up to 9% elongation to the chain, yielding tunable light-emitting wavelengths from 345 to 561 nm.
