Prediction of the chemical shrinkage of Portland cement

Chemical shrinkage is one of the main reasons leading to the early age deformation of concrete. Hence, the prediction of chemical shrinkage is an important issue for evaluating the deformation of concrete and its influence on the durability of concrete structures. There is still room to improve the accuracy for predicting the chemical shrinkage...

A 2 × 2 array receiver at 1.4 THz based on HEB mixers and a Fourier phase grating local oscillator

We report on realization of a 2 × 2 NbN hot electron bolometer (HEB) array receiver using multiple local oscillator (LO) beams that are obtained from a Fourier phase grating mirror. The grating splits a 1.4 THz single beam into four uniform sub-beams. Two 50mm lenses are applied to collimate each beam in order to achieve a spacing of 12mm...

Fourier phase grating for THz multi-beam local oscillators

A Fourier phase grating mirror will be applied to split a single, coherent terahertz source beam into multi-beams, which are spatially distributed as required for the local oscillator in an array receiver. We report on the simulation, design and fabrication of a Fourier phase grating at 1.25 THz for generating 2×2 beams, and the measurements at...