Design of an optical linear-discriminant filter: optimization for enhancement of filter transmittance and discrimination accuracy.

To discriminate fine concave and convex defects on a dielectric substrate, an optical machine learning system is proposed. This system comprises an optical linear-discriminant filter (OLDF) that performs linear discriminant analysis (LDA) of the scattered-wave distribution from target samples. However, the filter output from the OLDF is considerably weak and cannot be measured experimentally. Therefore, an algorithm is also proposed to improve the discrimination accuracy and filter transmittance. The designed filter is validated using a rigorous optical simulator based on vector diffraction theory. We also analyze and discuss a mechanism that provides high transmittance with high discrimination accuracy.

Design of an optical linear discriminant filter for classification of subwavelength concave and convex defects on dielectric substrates.

Identification of the defect type on substrate materials is essential for enhancing their yield ratio. We propose a novel optical filter to discriminate between subwavelength-order concave and convex defects on flat surfaces. This filter performs Fisher's linear discriminant analysis using light wave diffraction. The defect type is discriminated by simply comparing the irradiance at an observation point with the threshold value. Neither the defect image nor phase data, nor a large amount of data processing by a computer, is necessary. Numerical discrimination simulations indicate a discrimination error of 0.85%, and the noise tolerance of the proposed system is also discussed.

Effects of Residual Silanol on Solid Phase Extraction of Organic Compounds to Octadecylsilyl Silica.

Batchwise equilibrium study was carried out on the retention of nonpolar and polar organic compounds to octadecylsilyl (ODS) silicas of different properties at atmospheric pressure. While nonpolar compounds were retained only by distribution on the ODS phase, polar compounds were retained by both distribution and Langmuir-type adsorption on residual silanol. Retention on ODS silica with more silanol proceeded at a higher rate than retention on ODS silica with less silanol and was reversible on this solid phase extraction time-scale. An increase in surface density of ODS decreased the distribution constant, due to a decrease in fraction of ODS functioning as an extracting medium and also decreased the saturated adsorption amount, due to reductions of the residual silanol and the functioning ODS. The ODS silica with the lowest ODS density showed a distribution constant 31 times higher and a saturated adsorption amount 27 times higher than the ODS silica with the highest ODS density. On the other hand, because the interaction between the organic part and the ODS group introduced at higher density is strengthened, the adsorption constant is increased by about 5 times compared to the low density ODS silica. The electronic effects of substituents to nitrogen- and oxygen-containing compounds on retention were discussed. In conclusion, ODS silica with an appreciable amount of residual silanol is superior for solid phase extraction.

Profile reconstruction of a local defect in a groove structure and the theoretical limit under the vector diffraction theory.

The profile of a fine local defect in a periodic surface relief structure is reconstructed from a scattered wave. This defect cannot be imaged with an optical imaging system owing to the diffraction limit, and complicated multiscattering among the high-aspect-ratio grooves and the defect makes it difficult to reconstruct the profile using the scalar diffraction theory. We propose and numerically demonstrate a reconstruction algorithm by applying an efficient vector analysis method-the difference-field boundary element method. We also classify the profile according to the difficulty of reconstruction, which depends on the observation system and the noise level. Finally, this analysis provides the accuracy and limit of reconstruction under the vector diffraction theory.

Roles of Residual Silanol in Solid Phase Extraction of Copper to Octadecylsilyl Silica in the Presence of Acetylacetone.

Batchwise studies have demonstrated that the retention of acetylacetone (Haa) from an aqueous phase in non-endcapped octadecylsilyl (ODS) silica with silanol intentionally left (NEC) is stronger than the retention in endcapped ODS silica under ambient pressure, due to the enhanced wettability and the contribution of adsorption to silanol (-SiOH) as well as of the distribution into the ODS phase. Equilibrium analysis on solid phase extraction (SPE) of copper ion with Haa to NEC has indicated the adsorption of 1:1 species by the proton replacement reaction with silanol to give [-SiOCu(aa)] at relatively low Haa concentrations and the adsorption of [Cu(aa)2] to silanol, as well as the distribution of [Cu(aa)2] into the ODS phase. These adsorbed and distributed species of the same composition could be differentiated by ESR spectroscopy. The advantages of residual silanol in SPE of metal ions are discussed.

Slow, Mid-saturated Exchanges by Large Anions on Resins due to Increase in Independency of Exchange Sites with Cross-Linking.

Ion exchanges by aromatic anions (AAs) of varying volumes on anion exchange resins of different cross linking (CL)-degrees were studied. The exchanges on the resins with low CL-degrees having the larger and the less independent exchange sites proceeded fast and completely at a high AA concentration; the selectivity coefficient increased with the progress of the exchange, due to the cooperative interaction between exchanged AAs. In contrast, in the exchanges on the resins with a CL-degree of 8% having the smaller (more specifically, having the average volume of 300 Å3 with a variance) and the more independent exchange sites, the large AA may not enter the exchange sites having sizes smaller than the volume of AA to cause mid-saturation of ion exchange and to increase the reaction time because of the need for detouring; the selectivity coefficients were substantially independent of the progress of the exchange, due to the isolation of each AA.

Field-stitching boundary element method for accurate and rapid vectorial diffraction analysis of large-sized one-dimensional diffractive optical elements.

We propose a field-stitching boundary element method (FSBEM) for diffraction analyses for large diffractive optical elements (DOEs). A field stitching (FS) method separately computes the divided sections of a large DOE and provides the field distribution without field mismatching. However, a divided section must be largely overlapped, which is not efficient in terms of computational resources. In the FSBEM, in addition to spatial division, the electromagnetic field is computed for each component-the reflected, difference, and stitching fields-for rapid convergence of the solution. We validate the FSBEM by computing a one-dimensional DOE and evaluating the convergence property. The sample structure is also computed by the conventional FS method, and the advantages of the FSBEM are discussed.

Effects of Functional Group Density in Stylene-Divinylbenzene Copolymer Phase and of Supporting Electrolyte Concentration in Aqueous Phase on Performance of Iminodiacetate-type Chelating Resin in Terms of Contribution of Ion-Exchange Mechanism.

The effects of the functional group density in the stylene-divinylbenzene copoymer phase and of the supporting electrolyte concentration in the aqueous phase on the perfomance of the iminodiacetate (IDA)-type chelating resin were studied in terms of contribution of an ion-exchange mechanism. High hydrophobicity of the resin having a low functional group density interfered with penetration of aqueous solutions into the resin phase to slow the acid-base reaction and the adsorption reaction. Uptake of the cation in the supporting electrolyte into the resin phase was clearly indicated in each of two acid dissociation reactions. The high concentration of the supporting electrolyte enhanced acid dissociation of the IDA group, and a singly deprotonated species interacting with the supporting electrolyte cation strongly interfered with adsorption by the ion-exchange mechanism, while only slightly interfering with adsorption by the complexation. Both the complexed and ion-exchanged species respectively involving two or more IDA groups were destabilized to reduce the adsorption capacity of the resin having the low functional group density.

Fast actual-size vectorial simulation of concave diffraction gratings with structural randomness.

In this study, an actual-size concave grating with structural randomness is numerically analyzed. Numerical electromagnetic analyses that solve Maxwell's equations can provide rigorous diffracted fields including the polarization characteristics. However, because of high computational costs, actual-size gratings with no periodicity have seldom been analyzed. We apply the difference-field boundary element method (DFBEM) for the analyses of actual-size concave gratings with 10,000 random blazed grooves. The DFBEM provides vectorial diffracted or scattered waves with very low computational resources. First, we estimate the accuracy of the computation results, and then we show some relations between the degree of randomness and the diffraction efficiency, including the polarization dependency.

pH-Independent Recognition of Polyhydroxy Compounds by Niobium(V) Porphyrin Complex with Unique Sugar Selectivity.

The niobium(V) complex with tetraphenylporphin having OH- as an auxilliay ligand exists as a dimeric complex, [Nb2(tpp)2O3] at a total concentration >10-4.5 mol dm-3, and reacts with an aliphatic or aromatic polyhydroxy compound to form a monomeric complex containing chelate rings by coordination of the deprotonated species, and to cause an appreciable UV-Vis spectral change. In contrast to phenylboronic acid (PBA), the reactivity of [Nb2(tpp)2O3] is independent of pH at least between 4 and 8. Aliphatic comounds are more reactive than aromatic compounds in dioxane-water, while the reactivity order is reversed in the two-phase reaction. The sugar selectivity order of [Nb2(tpp)2O3] in dioxane-water (10:1) (sorbose > fructose >> mannose > arabinose, galactose > glucose) is appreciably different from that of PBA (fructose > sorbose >> arabinose > galactose > mannose > glucose). This may be related to the difference in size of the Lewis acidic center.

Triphosphate Ion-Selective Electrode Based on Zr-Porphyrin Complex.

Ion-selective electrode using zirconium(IV) complex with octaethylporphin (H2oep) as a carrier showed high selectivity to triphosphate (TP, H5tp) against other hydrophilic anions including diphosphate and phosphate. The electroactive species was identified to be [(Zr4(oep)4(Htp)2] (TP/Zr ratio of 0.5) of the unique structure; triphosphates are recognized by one Zr atom through three O atoms on three different P atoms and by another Zr atom through two O atoms on two terminal P atoms and are also involved in complementary intermolecular hydrogen bonding to be surrounded by four porphyrin complexes. In contrast, Zr(IV) in the other complex with tetraphenylporphin has the higher Lewis acidity, due to the electron-withdrawing property of phenyl rings and, at the higher TP concentration, forms a species having a TP/Zr ratio of unity, which precipitates to lose the electroactivity. The electrode was successfully applied to monitor hydrolysis of TP that provides diphosphate and phosphate.

Interactions of Anion-Exchange Resins with Polyacrylates in Atmosphere.

The interactions of polyacrylates (PAs with mean molecular weight of 4.5, 25, and 250 kDa; Na+,pa-) with anion exchange resins in the Br- form (AXRs; -R+,Br-) were studied under practical conditions by reaction stoichiometry and spectroscopy. The stoichiometric or an excess amount of PA(4.5 kDa) completely replaced Br- in the AXRs of the cross-linking degree of 2 or 8%, respectively, to give (-R+,pa-), due to enhancement in selectivity of carboxylate group by multiple interactions. In contrast, PA(250 kDa) exchanged Br- only on the surface of AXRs and did not penetrate into the resins; CO2 was involved in the system to induce exchange with CO32-. Using the slightly acidic condition caused substantially no exchange by CO32- but induced coextraction of PA with proton as free Hpa. PA(4.5 kDa) once penetrating into the resin phase as (-R+,pa-) or free Hpa was reversibly eluted under the appropriate conditions.

Erratum: Analytical Sciences, 2016, Vol. 32, No. 3, p. 343, Enhanced Retention of Chelating Reagents in Octadecylsilyl Silica Phase by Interaction with Residual Silanol Groups in Solid Phase Extraction of Divalent Metal Ions.

On page 343, the abstract, the second line,with which octadecylsilyl silica (ODS), was impregnated with was studiedshould readwith which octadecylsilyl silica (ODS) was impregnated, was studied.

Enhanced Retention of Chelating Reagents in Octadecylsilyl Silica Phase by Interaction with Residual Silanol Groups in Solid Phase Extraction of Divalent Metal Ions.

Solid-phase extraction (SPE) of divalent metal ions with a lipophilic and potentially divalent hexadentate chelating reagent (H2L), with which octadecylsilyl silica (ODS), was impregnated with was studied to gain more insight into and develop the potential of this methodology. This is the first time to demonstrate that this reagent as well as other common nitrogen-containing reagents were retained both by adsorption due to hydrogen bonding between nitrogen atoms of the reagent and residual silanol groups in the ODS phase and by simple distribution into the hydrophobic space. An appreciably large amount of this reagent could be retained by the adsorption mechanism even with a relatively thin loading solution. The divalent metal ions of Mn(2+), Co(2+) and Zn(2+) were extracted as 1:1 neutral complexes ([ML]), while Ni(2+) and Cu(2+) as ion-pairs of 1:1 cationic complex ([MHL](+)) with anion in SPE with H2L. The extractability and selectivity were substantially the same as that in liquid-liquid extraction.

Expansion of the difference-field boundary element method for numerical analyses of various local defects in periodic surface-relief structures.

We expand the difference-field boundary element method (DFBEM) to calculate wave scattering from a variety of local periodic structure defects. The DFBEM is a numerical method for simulating the diffraction caused by a periodic surface-relief structure with a defect. Although it is more efficient than conventional techniques such as the finite-difference time-domain (FDTD) method, the original DFBEM is limited to projection defects. Here, we derive the integral equations and expressions for crack and buried-pillar defects, and also demonstrate some numerical analyses, validating the results by comparison with results from the FDTD method and the dielectric interface boundary conditions.

Design of ultra-compact triplexer with function-expansion based topology optimization.

In this paper, in order to optimize wavelength selective photonic devices using the function-expansion-based topology optimization method, several expansion functions are considered and the influence on the optimized structure based on each expansion function was investigated. Although the Fourier series is conventionally used in the function-expansion-based method, the optimized structure sometimes has a complicated refractive index distribution. Therefore, we employed a sampling function and a pyramid function to obtain a simpler structure through the optimal design. A triplexer was designed by using our method, and the comparison between the optimized structures based on the three expansion functions was also discussed in detail.

Redox potentials and HPLC behavior of cobalt and iron complexes with pyridylazo compounds.

The redox potentials of cobalt and iron complexes with ten pyridylazo compounds, E(0)(ML2) (ML(2)(+/0); M: Co(III/II), Fe(III/II); L(-): pyridylazo compounds), have been determined in order to explore the difference in their reversed-phase HPLC behavior. The redox potentials of Co complexes were in the range of -0.62 - 0.03 V, while those of Fe complexes were -0.06 - 0.59 V relative to 0.20 V for ferricinium/ferrocene. The redox potentials of both the Co and Fe complexes were linearly correlated to the basicities of the ligands. The correlation was quantitatively explained by a difference in dependence of the stabilities of M(III) and M(II) complexes on the ligand basicities. The complex of [Co(III)L(2)](+) or [Fe(II)L(2)] with any compound injected in the reversed-phase HPLC system was detected without any change in the composition. When [Co(II)L(2)] was injected, only those complexes having the highest potentials of E(0)(CoL2) congruent with 0.0 V were detected as [Co(II)L(2)], while other complexes having lower potentials gave a peak of [Co(III)L(2)](+). When [Fe(III)L(2)](+) was injected, only complexes having the lowest potentials of E(0)(FeL2) congruent with 0.0 V were detected as [Fe(III)L(2)](+), while others having higher potentials gave a peak of [Fe(II)L(2)].

Synthesis of a multichannel lattice-form optical delay-line circuit with ring waveguides.

This paper presents a one-input M -output (1 x M) circuit configuration and a synthesis algorithm for realizing an optical infinite impulse response (IIR) lattice filter having M -output channels (M > or =2) .The circuit configuration has a multilayer structure consisting of multiple Mach-Zehnder interferometers with delay time difference of Deltatau. It is a natural extension of the conventional two-port optical IIR lattice circuit (M =2) . Synthesis algorithm is derived to obtain all unknown circuit parameters. The proposed synthesis algorithm is based on factorizations of the paraunitary total transfer matrix. Simulation result demonstrates the effectiveness of the proposed multichannel IIR design scheme. The synthesis algorithm for M - channel IIR filter is considered lossless in this paper, which implies that the filter must be power complementary.

Liquid-liquid extraction and liquid chromatographic studies on interactions of inorganic anions with coordinatively unsaturated copper(II) complexes of heterocyclic azo compounds.

The interactions between Cu(II) complexes with heterocyclic azo compounds and several anions were studied by equilibrium analysis of ion-pair extraction, RP-HPLC of metal complexes, and ion chromatography of anions on an ODS column coated with Cu(II) complexes of the long alkyl derivatives. Both ion-pair extraction and HPLC studies demonstrated that a dicationic complex with 8-(3,5-dibromo-2-pyridylazo)-5-aminoquinoline interacted with anions stronger than a monocationic complex with 2-(2-pyridylazo)methylphenol. Anions were more retained on the column coated with dicationic Cu(II) complex. Such differences were quantitatively ascribed to the first ion-pair formation of the dicationic complex giving a monocationic species.

Bidentate and tridentate heterocyclic azo compounds having long alkyl chains as coating reagents for ion chromatography of manganese, zinc, and cadmium ions.

Bidentate and tridentate heterocyclic azo compounds with and without a long alkyl chain were prepared and examined for cation exchange chromatography of manganese, zinc, and cadmium; these ions could not be separated by reversed phase HPLC following precolumn derivatization with heterocyclic azo compounds owing to the dissociation of the complexes. The newly prepared azo compounds having a long alkyl chain favorably orientate in the reversed-phase stationary phase such that the coordinating parts of the ligand may make contact with metal ions in the mobile phase. Bidentate ligands showed sharp peaks but almost no resolution of manganese and cadmium. A tridentate ligand strongly retained all the three metal ions, which could be separated within 10 min by a competing ligand and by optimizing the pH.