MCNP simulation and experimental study in situ low-grade copper analysis based on PGNAA.

A prompt gamma neutron activation analysis (PGNAA) facility utilizing Cf source has been developed for in situ analysis of copper samples. Monte Carlo simulation is employed to determine optimal sizes for neutron moderator, gamma-ray shielding material, and thermal neutron absorber. Subsequently, based on the parameters optimized by MCNP, the PGNAA facility was constructed.

Mechanical, Structural and Electronic Properties of CO Adsorbed Graphitic Carbon Nitride (g-CN) under Biaxial Tensile Strain.

We investigate mechanical, structural and electronic properties of CO adsorbed graphitic carbon nitride (g-CN) system under biaxial tensile strain via first-principles calculations. The results show that the stress of CO adsorbed g-CN system increases and then decreases linearly with the increasing biaxial strain, reaching maximum at 0.12 strain.

Equibiaxial Strained Oxygen Adsorption on Pristine Graphene, Nitrogen/Boron Doped Graphene, and Defected Graphene.

We report first-principles calculations on the structural, mechanical, and electronic properties of O molecule adsorption on different graphenes (including pristine graphene (G-O), N(nitrogen)/B(boron)-doped graphene (G-N/B-O), and defective graphene (G-D-O)) under equibiaxial strain. Our calculation results reveal that G-D-O possesses the highest binding energy, indicating that it owns the highest stability. Moreover, the stabilities of the four structures are enhanced enormously by the compressive strain larger than 2%.

[Detection technology of methane gas concentration based on infrared absorption spectrum].

According to the disadvantages of current methane sensor in coal mine, the infrared methane concentration detection system based on the principle of infrared spectrum absorption was designed using differential absorption technology. In the system single light beam absorbing cell and single light beam and double wavelengths technology are adopted. Differential amplifier circuit serves as the core of faint signal processing circuit that detects the output signal of methane concentration, and linear formula fits the curve of methane concentration and output voltage, which realizes accurate and full range detection of gas concentration.