Multistep ion exchange processes of gradient refractive index rod lens.

A mathematical model for research on the refractive index profile (RIP) of multistep ion exchange processes (IEPs) of gradient refractive index rod lenses (GRINs) is established by the different initial condition and boundary condition, based on the Fickian diffusion equation. GRIN rod lenses have been fabricated using the three-step IEPs. Research results indicate that the experimental deviations of refractive index (DRI) are in good agreement with the theoretical data.

Nondestructive measurement of refractive index profile of gradient refractive index rod lens.

In this paper, a simple nondestructive method is described to obtain the refractive index profile of a gradient refractive index rod lens by means of optical coherence tomography. The approach exploits the fact that optical coherence tomography provides a direct measurement of the optical path of the light traveled through a gradient refractive index rod lens. The refractive index profile for a gradient refractive index rod lens is retrieved by iterative fitting of the optical path calculated by the ray tracing method with that experimentally measured using optical coherence tomography.

Photodissociation dynamics of 2-bromopropane using velocity map imaging technique.

Photodissociation dynamics of 2-bromopropane in the A band was investigated at several wavelengths between 232 and 267 nm using resonance-enhanced multiphoton ionization technique combined with velocity map ion-imaging detection. The ion images of Br ((2)P(3/2)) and Br* ((2)P(1/2)) were analyzed to yield corresponding total translational energy and angular distributions. The total translational energy distributions showed that the channel leading to Br carried more internal energy in the 2-C(3)H(7) moiety than the channel leading to Br*.

Gradient refractive index square lenses. II. Imaging.

We establish theoretically the relationship between the lateral magnification m and the object distance L(0) for a gradient refractive index (GRIN) square lens and a GRIN rod lens. Through the linear fit of the object distance and the reciprocal of the magnification for different image locations, we use the imaging method to measure the central refractive index n(0) and focusing constant alpha of the GRIN square lens and the GRIN rod lens. The center refractive indices and focusing constant alpha of the GRIN square lens and the GRIN rod lens are 1.

Gradient refractive index square lenses. I. Fabrication and refractive index distribution.

An equation for the distribution of refractive index of a gradient refractive index square lens has been established, and such a lens has been fabricated using ion exchange. The distributions of refractive indices at different angles of incidence are discussed. Experimental and theoretical data are compared and show good agreement.

Numerical analysis of low chromatic aberration of a gradient refractive index rod lens.

The oxide compositions (OCs) model is established for discussing the chromatic aberrations of a gradient refractive index rod lens. The chromatic aberrations for Na(+)/Li(+), K(+)/Cs(+), and K(+)/Tl(+) ion exchanges are discussed based on the OC model and the Huggins-Sun-Davis (HSD) model. Theoretical results indicate that the function value mainly depends on base glass properties and the nature of exchanging ion pairs, and rarely depends on the quantity of ion exchange.

Electrochemical reduction and voltammetric determination of metronidazole at a nanomaterial thin film coated glassy carbon electrode.

Simple and sensitive electrochemical method for the determination of metronidazole, based on a nanostructured film coated glassy carbon electrode (GCE), is described. Multi-walled carbon nanotubes (MWNT) was dispersed into water in the presence of a hydrophobic surfactant to give very stable and homogeneous MWNT suspension, and a MWNT-film coated GCE was achieved via evaporating solvent. Metronidazole yields a well-defined reduction peak whose potential is -0.

Poly[bis-[μ-1,4-bis-(imidazol-1-ylmeth-yl)benzene]dichloridocadmium(II)].

The title compound, [CdCl(2)(C(14)H(14)N(4))(2)](n), has a slightly distorted octa-hedral coordination geometry, formed by four N atoms from 1,4-bis-(imidazol-1-ylmeth-yl)benzene ligands and two Cl atoms, giving a two-dimensional network. The Cd atom lies on a centre of inversion.

Hexakis(1H-imidazole-κN)nickel(II) bis-(2,4-dibromo-6-formyl-phenolate) N,N-dimethyl-formamide disolvate.

In the cation of the title compound, [Ni(C(3)H(4)N(2))(6)](C(7)H(3)Br(2)O(2))(2)·2C(3)H(7)NO, the Ni(II) ion lies on an inversion center and is coordinated in a slightly distorted octa-hedral environment by six N atoms from six imidazole ligands. In the crystal structure, cations, anions and solvent mol-ecules are linked by inter-molecular N-H⋯O hydrogen bonds into one-dimensional chains along [010]. In addition, the crystal structure is stabilized by weak C-H⋯O and C-H⋯N hydrogen bonds.

Bis{μ-2,2'-[o-phenyl-enebis(nitrilo-methyl-idyne)]diphenolato}dicopper(II) N,N'-dimethyl-formamide disolvate.

The title compound, [Cu(2)(C(20)H(14)N(2)O(2))(2)]·2C(3)H(7)NO, consists of a centrosymmetric dimer composed of two copper(II) ions and two tetra-dentate salphen ligands {H(2)salphen is 2,2'-[o-phenyl-enebis(nitrilo-methyl-idyne)]diphenol}, and two dimethyl-formamide solvent mol-ecules. The Cu(II) atom is bonded to two N imino atoms and three phenolate O atoms of salphen. One deprotonated phenol group of each ligand bridges two Cu atoms, forming the dimer.

[Age estimation and age structure of Cycas fairylakea population in Shenzhen City].

Based on the structural characteristics of Cycas trunk, including vegetative leaf base scars, sporophyll concave rings, and average occurrence probabilities of vegetative leaf and sporophyll, a method for the age estimation of Cycas fairylakea population was developed, and the age of each individual was calculated. Three approaches, i.e.

Bis{μ-2,2'-[ethane-1,2-diylbis(nitrilo-methyl-idyne)]diphenolato}dinickel(II).

The asymmetric unit of the title compound, [Ni(2)(C(16)H(14)N(2)O(2))(2)], contains an Ni(II) cation which is coordinated by two imine N atoms and by two phenolate O atoms of the salen ligand {salen = N,N'-bis-(salicyl-idene)ethane-1,2-diamine or 2,2'-[ethane-1,2-diyl-bis(nitrilo-methyl-idyne)]diphenol}, leading to a distorted square-planar conformation. When a secondary Ni-O inter-action > 2.41 Å to the neighbouring phenolate O atom is considered, two mol-ecules are linked into a centrosymmetric dimer with an overall square-pyramidal coordination for the Ni(II) cation.

Safety evaluation of short-term exposure to chitooligomers from enzymic preparation.

Chitooligomers have significant application to the development of functional foods. This paper evaluated systematically the safety of chitooligomers, which were prepared by enzymatic depolymerization of chitosan. The oral maximum tolerated dose of this chitooligomes was more than 10 g/kg body weight in mice.

[The genetic analysis of Al-tolerance in maize].

The heredity of Al-tolerance was studied in different Al-tolerance of two inbred lines of maize and their F1, F2, B1 and B2 generations by the means of nutritional cultivation. The results indicated that the relative biomass (Al/CK) of root had high hereditary variance, the broad-sense heredity reached 78.6 %, but narrow-sense heredity only had 15.

A multi-wall carbon nanotubes-dicetyl phosphate electrode for the determination of hypoxanthine in fish.

An enzymeless sensor based on a multi-walled carbon nanotubes-dicetyl phosphate (MWCNT-DCP) film modified vitreous carbon electrode was developed for the determination of hypoxanthine. The MWCNT-DCP film modified electrode showed a remarkable enhancement effect on the oxidation peak current of hypoxanthine. Under the optimized conditions, the oxidation peak current is proportional to the concentration of hypoxanthine over the range from 5.