Biomedical subjects

Jianhua Jiang

Publications and source records attributed to Jianhua Jiang.

6 recordsLinked to original sources

PubMed2005

Stratified waveguide grating coupler for normal fiber incidence.

We propose a new stratified waveguide grating coupler (SWGC) to couple light from a fiber at normal incidence into a planar waveguide. SWGCs are designed to operate in the strong coupling regime without intermediate optics between the fiber and the waveguide. Two-dimensional finite-difference time-domain simulation in conjunction with microgenetic algorithm optimization shows that approximately 72% coupling efficiency is possible for fiber (core size of 8.3 microm and delta=0.36%) to slab waveguide (1.2-microm core and delta=3.1%) coupling. We show that the phase-matching and Bragg conditions are simultaneously satisfied through the fundamental leaky mode.

Journal Article↗

PubMed2005

Preparative SEC column packed with microporous particles prepared from cellulose.

New microporous particles with large pore size (mean pore diameter of 820 nm) are successfully prepared from a mixture of cellulose and konjac glucomannan (RC-KGM3) in 1.5 M NaOH-0.65 M thiourea aqueous solution by coagulating with 5 weight percentage (wt%) CaCl(2), and then 2 wt% HCl aqueous solution. A preparative size-exclusion chromatographic (SEC) column packed with the gel particles is used for the fractionation of a dextran in water. The exclusion limit and fractionation range of the stationary phase are molecular masses of 125 yen 104 g/mol and 5.6 yen 104 to 125 yen 104 g/mol, respectively. The dextran [dextran 50, weight-average molecular mass (M(w)) = 40.1 yen 104 g/mol, polydispersity index (d) = 3.5] is fractionated by the preparative SEC column to obtain six fractions, and four of them are refractionated twice by the same preparative SEC column. The refractionated samples F-3-3 and F-4-3 are characterized by analytical SEC combined with laser light scattering and light scattering to obtain M(w) of 91.8 and 61.9 yen 104 g/mol, as well as d of 1.3 and 1.4, respectively. The results indicate that the fractions having narrow molecular mass distribution are satisfactorily prepared with the SEC column. The described SEC column can be successfully used to fractionate polymers in aqueous solution.

Cellulose↗

PubMed2005

Determination of nifuratel in human plasma by HPLC and study on its pharmacokinetics.

A simple and sensitive reversed-phase high-performance liquid chromatography method using UV detection is established for the determination of nifuratel in human plasma and applied to a study of its pharmacokinetics. Plasma samples are extracted with ethyl acetate. A C(18) column and a mobile phase of 0.01 M (pH 7) phosphate buffer (KH(2)PO(4)) and acetonitrile (61:39, v/v) are used. Analysis is run at a flow rate of 1.0 mL/min with the detector operated at a wavelength of 367 nm. The calibration curve is linear over a concentration range of 0.2-40 ng/mL with a correlation coefficient of 0.9996. The limit of detection is 0.1 ng/mL. The mean absolute recovery value is greater than 80%. The intraday precision (relative standard deviation) ranges from 1.89% to 7.32%, and the interday precision ranges from 1.71% to 7.83%. The results show that the area under the plasma concentration-time curve, time to maximum observed plasma concentration, maximum concentration reached in the concentration profile, and elimination half-life between the testing tablets and reference tablets have no significant difference (P > 0.05). Relative bioavailability is 104.0% +/- 16.5%.

Chromatography, High Pressure Liquid↗

PubMed2004

Three-dimensional analysis of a hybrid photonic crystal-conventional waveguide 90 degree bend.

We present a three-dimensional (3D) analysis of a hybrid photonic crystal-conventional waveguide 90 degree bend proposed previously [Opt. Express 10, 1334 (2002)] as an ultracompact component for large-scale planar lightwave circuit integration. Both rigorous 3D finite-difference time-domain modeling and a simple perfect mirror model analysis were carried out for different Si post heights in the photonic crystal region. Results show that the bend efficiency increases rapidly with Si post height. For a post height of 6.5 microm, this structure yields a bend efficiency of 97.3% at a wavelength of 1.55 microm for 90 degree bends in 2 microm x 2 microm square channel conventional waveguides with a refractive index contrast of 3.55%, which is very close to the bend efficiency of 98.2% for the corresponding two-dimensional problem. Our 3D analysis permits the examination of issues such as out-of-plane scattering loss and the effects of finite Si post height that are not considered in two dimensions.

Journal Article↗

PubMed2003

Parallel microgenetic algorithm design for photonic crystal and waveguide structures.

We have developed a powerful parallel genetic algorithm design tool for photonic crystal and waveguide structures. The tool employs a small-population-size genetic algorithm (microgenetic algorithm) for global optimization and a two-dimensional finite-difference time-domain method to rigorously design and optimize the performance of photonic devices. We discuss the implementation and performance of this design tool. We demonstrate its application to two photonic devices, a defect taper coupler to connect conventional waveguides and photonic crystal waveguides, and a sharp 90 degrees waveguide bend for low index contrast waveguides.

Journal Article↗

PubMed2003

Ultracompact high-efficiency polarizing beam splitter with a hybrid photonic crystal and conventional waveguide structure.

We propose an ultracompact high-efficiency polarizing beam splitter that operates over a wide wavelength range and is based on a hybrid photonic crystal and a conventional waveguide structure. Within a small area (15 microm x 10 microm), this polarizing beam splitter separates TM- and TE-polarized modes into orthogonal output waveguides. Results of simulations with the two-dimensional finite-difference time-domain method show that 99.3% of TM-polarized light is deflected by the photonic crystal structure (with a 28.0-dB extinction ratio), whereas 99.0% of TE-polarized light propagates through the structure (with a 32.2-dB extinction ratio). Wave vector diagrams are employed to explain the operation of a polarizing beam splitter. Tolerance analysis reveals a large tolerance to fabrication errors.

Journal Article↗