Biomedical subjects

Yen-Ru Lee

Publications and source records attributed to Yen-Ru Lee.

3 recordsLinked to original sources

PubMed2006

Multiple wave diffraction anomalous fine structure.

A new method, multiple-wave diffraction anomalous fine structure, combining the x-ray multiple-wave diffraction and diffraction anomalous fine structure techniques, is proposed. The real part of dispersion correction Deltaf' and fine structure chi function can be obtained directly by multiple diffraction analysis without using Kramers-Krönig relations and kinematical fitting of diffracted intensity. Better wave vector sensitivity of the fine structure is expected. The multiple-wave diffraction anomalous fine structure experiment for a GaAs single crystal is reported as an example.

Journal Article↗

PubMed2004

X-ray multiple-wave coherent interaction in a quasi-two-dimensional material NbSe2-2H.

The first observation of the X-ray multiple-wave interaction in an incommensurate charge-density-wave (CDW) modulated structure at low temperatures is reported for an example of a quasi-two-dimensional material, NbSe(2)-2H. Via the coherent interaction between the X-ray waves propagating in the CDW-modulated structure and the host structure, the phase-dependent intensity variations of a CDW reflection were detected. In accord with a centrosymmetric structure, the phases of the structure-factor triplets of two CDW reflections and a Bragg reflection of the host structure were determined to be either 0 or 180 degrees, and not to vary with temperature. Relative phase differences of the two CDW reflections are also deduced.

Crystallography, X-Ray↗

PubMed2003

Phase-dependent polarization aspects of three-wave X-ray diffraction: an iterative Born approximation.

The iterative Born approximation is derived for three-wave dynamical X-ray diffraction. Dependence of the three-wave diffraction profiles of the diffracted wave on the polarization state of a linearly polarized incident wave is theoretically and experimentally investigated. General conditions of the phase sensitivity as well as the asymmetry of diffraction profiles are obtained from this approximation and compared with direct dynamical calculations. Reasonable qualitative agreement between the results obtained from this iterative approach and the exact dynamical calculation is shown. A new feature of reversing asymmetry of an intensity profile with respect to phase change is theoretically predicted.

Journal Article↗