45° double-drive photoelastic modulation.

In this report, a new type of double-drive photoelastic modulation effect is studied. Two piezoelectric actuators are connected to a symmetric photoelastic crystal at an angle of 45°. The actuators and crystal have the same resonant frequency.

[The Research of Spectral Polarization Imaging Detection System Based Dual-AOTFs].

Acousto-optic tunable filter (AOTF) has the advantages of small size, good stability, wide range of wavelength scanning, quick modulation speed and so on. So AOTF is widely used in spectral imaging. But the detection of spectral polarization imaging is seldom found by using AOTF individually.

[A New Strategy of Spectrum and Polarization Measuring based on LCVR and AOTF].

In view of the existing relatively cumbersome polarization measurement method of using liquid crystal phase variable retarder (LCVR) and acousto-optic tunable filter (AOTF), a new strategy of spectrum and polarization measurement is put forward. This method removed mechanical movement and reduced the amount of phase delay from four groups to two groups. This method realizes the spectrum and polarization measurements by measuring the plus and minus 1 level diffraction light of the system with two LCVR, one AOTF and two same version detectors.

[Survey of feeding patterns in 437 infants from Huining County of Gansu Province].

Objective: To investigate the feeding patterns of infants in Huining County, Gansu Province, an economically undeveloped county in China, so as to provide scientific evidence for nutritional intervention.

Methods: By cluster sampling based on the area distribution and the economic state, 437 children from 7 different areas in Huining County, Gansu Province were enrolled. A questionnaire on the feeding patterns within 24 months of age was completed by the caregivers.