Biomedical subjects

M B Yu

Publications and source records attributed to M B Yu.

4 recordsLinked to original sources

PubMed2006

Tunable superprism and polarization splitting in a liquid crystal infiltrated two-dimensional photonic crystal made of silicon oxynitride.

Tunable superprism and polarization splitting effects, based on liquid-crystal infiltrated two-dimensional photonic crystal with SiON as a background material, are demonstrated. Owing to the strong birefringence of the liquid crystal, the dispersion curves of the two polarizations are distinctly different, resulting in large splitting between the two polarizations. Extremely large splitting, as large as 80 degrees, can be obtained. Moreover, the splitting can be tuned to a substantial degree when the optic axis of the liquid crystal is reoriented. Fully controllable, incident-angle-dependent and wavelength-dependent superprism effects are also demonstrated. This large swing in the refraction can be completely switched off by reorientation of the optic axis of the liquid crystal, thus to resemble bulk media refraction.

Journal Article↗

PubMed2006

Symmetry properties of two-dimensional anisotropic photonic crystals.

A theoretical study of two-dimensional photonic crystals made of anisotropic material is presented. Detailed computation principles including a treatment of the TE and TM polarizations are given for a photonic crystal made of either uniaxially or biaxially anisotropic materials. These two polarizations can be decoupled as long as any one of the principal axes of the anisotropic material is perpendicular to the periodic plane of the photonic crystal. The symmetry loss due to the anisotropy of the material and the variation of the Brillouin zones relative to the tensor orientations are also analyzed. Furthermore, the symmetry properties of the two-dimensional photonic band structure are studied, and the resulting effect on the photonic bandgap and the dispersion properties of photonic crystal are analyzed as a function of the orientation of the anisotropic material.

Journal Article↗

PubMed1994

[A study on retinal light sensitivity of normal human visual fields].

The full threshold program of QZS-2 automated perimetry made in China was used to measure the retinal light sensitivity of the central 30 degrees and peripheral 30 degrees-60 degrees visual fields of 111 eyes of 59 normal persons. Their ages ranged from 15-68 years and the average age was 38.4 years. From the corresponding respective comparisons of the results, it is shown that the mean light sensitivity of the macular, central 30 degrees and peripheral 30 degrees-60 degrees visual fields between the left and right eyes has no statistical significant differences (P > 0.05), and there are also no statistical significant differences (P > 0.05) in the mean light sensitivity of the central and peripheral fields between the male and female subjects. The mean light sensitivity declines linearly with the increase of age and eccentricity. The mean light sensitivity of the central and peripheral visual fields decreases 0.6 dB and 0.7 dB, respectively, with each one decade increase of age. The mean light sensitivity also decreases by 2.6 dB per 10 degrees eccentricity. The mean short-term fluctuation in the normal subjects is 1.39 +/- 0.56 dB.

Adolescent↗

PubMed1993

Computerized image analysis of smooth muscle fibers in normal Chinese men and impotence patients.

Smooth muscle fibers are considered very important in penile erection and relaxation. The reduction of intracavernosus smooth muscle fibers can provoke impotence. The percentage of smooth muscle fibers in corpus cavernosum specimens was studied quantitatively in normal men and impotence patients by means of computerized image analysis. The percentage of smooth muscle fibers in the specimens of 14 normal men, ranged from 41% to 61% (average 50%) and in 12 impotence patients, it was 22% to 46% (average 31%). A decrease of smooth muscle fibers and an increase of collagen fibers were noted in impotence patients.

Adult↗