Laser displacement meter application for milling diagnostics

This paper presents the application of a laser displacement meter for direct multi-purpose sensing of milling tool conditions. Using a laser displacement meter, a laser beam is projected onto the cutting tool and subsequently reflected. The intensity as well as the angle of the reflected beam are measured. The signals are interpreted for identification of tool geometry, tool whirling, or vibration. Signal processing and analysis depend on the application. A prototype system has been developed to demonstrate the feasibility of various applications, namely (1) tool setting evaluation, (2) in-process measurement of milling cutter geometry and detection of tool failure, (3) continuous monitoring of milling cutter deterioration, (4) detection and measurement of chatter in milling, (5) measurement of milling tool bending and (6) thermal expansion.     

Asymmetric Synthesis of Indoline from Achiral Phthalimide Involving Crystallization-Induced Deracemization

Asymmetric synthesis was performed by combining the photochemical reaction of an achiral substrate followed by crystallization-induced deracemization. The results indicated that a fused indoline produced by photochemical intramolecular δ-hydrogen abstraction and cyclization of N-(5-chloro-2-methylphenyl)phthalimide crystallized as a racemic conglomerate. Since this substrate has an aminal skeleton, racemization involving a ring-opening and ring-closing equilibrium process occurred under suitable conditions. Efficient racemization was observed in acetone containing a catalytic base, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Crystallization-induced dynamic deracemization by Viedma ripening from racemic indoline was performed with an excellent enantioselectivity of 99 % ee. Furthermore, one-pot asymmetric synthesis of the indoline was achieved by the photochemical reaction of achiral phthalimide followed by continuous attrition-enhanced deracemization converging to 99 % ee of enantiomeric crystals. This is the first example of asymmetric expression and amplification by photochemical hydrogen abstraction and crystallization-induced dynamic deracemization.     

Capillary electrophoresis of small anions in complex samples with a hollow fiber sampling inlet end.

A hollow fiber sampling inlet end of capillary electrophoresis (CE) for small ions in complex samples is described. A short piece of hollow fiber, which only permits small ions to pass through its wall, was directly connected to one end of a capillary. Small ions in complex samples were injected into the capillary through the hollow fiber by an electrokinetic method. The experimental results of CE for standard anion mixture solutions, river water, and milk samples show that the hollow fiber sampling inlet end is a simple and useful method for the CE of complex samples. Furthermore, it has been shown that the method can be used to study small anion changes during the milk storing process.     

A new class of flavonoids bearing macrocyclic polyethers by stereoselective photochemical cycloaddition reaction

A new class of flavonoids bearing cyclic polyethers involving a phenyl ring was conveniently provided by the intramolecular photochemical dimerization of 2-chromonecarboxylic esters. Irradiation of 2-chromonecarboxylate with a polyether tethered at both ends promoted intramolecular [2 + 2] cyclobutane formation leading to 14- to 27-membered cyclic polyethers. The efficiency depended on the substituted position of the phenyl ring, with ortho- and meta-substituted derivatives giving cycloadducts in good chemical yields and quantum efficiencies, whereas the para-derivatives were inert toward photolysis. X-ray crystallographic analysis revealed that the stereochemistry of the macrocyclic cycloadducts exhibited C₂-symmetry.     

Crystallization-induced diastereomer transformation of 2-quinolone-4-carboxamide followed by stereoselective intermolecular photocycloaddition reaction

2-Quinolone-4-carboxamide derived from (S)-proline, which exists as a mixture of two diastereomers before crystallization, converged to a single diastereomer by crystallization (CIDT), and the homochirality was transferred by a intermolecular 2 + 2 photocycloaddition reaction with high optical activity.     

Graft copolymerization induced by thermal reactions of the binary alkali salts of poly(carboxylic acid)–brominated carboxylic acid in bulk

Thermal reactions of the binary alkali salts of poly(carboxylic acid)–brominated carboxylic acid such as sodium or potassium poly(4-vinylbenzoate)-2-bromopropanoate [Na or K (PVBA-2-BPA)] in bulk were investigated. A methanol solution of binary acids was prepared by fixing the molar ratio of the repeating unit of polymeric acid to the fraction of brominated carboxylic acid. The binary salts were prepared by the neutralization of the binary acid solution. The product of the thermal reaction followed by esterification was identified as a graft copolymer containing PVBA in the main chain and polylactic acid in the side chain. The reaction of 1/15 K (PVBA-2-BPA) at 120 °C for 2 h yielded the highest percentage of grafting (300%). The grafting proceeded gradually for the initial 2 h and then somewhat. Reactivity of the K salt was higher than that of the corresponding Na salt. The thermal reaction of 1/10 K [polymethacrylate-2-BPA (PMA-2-BPA)] at 120 °C for 2 h also yielded a graft copolymer, and the percentage of grafting was 300%. However, reaction temperatures higher than 120 °C caused homopolycondensation of K 2-BPA prior to grafting, and homopolycondensation occurred prior to grafting in the reaction with Na (PMA-2-BPA). © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1877–1885, 2001     

Low concentrator hetero-junction microcrystalline silicon solar cells

Multi-junction silicon-based thin-film solar cells are attractive materials for further cost-reduction and high efficiency. Meanwhile, it is also well considered that a concentrator solar cell is another alternative approach to enhance the conversion efficiency. In concentrator solar cells, the photocurrent linearly increases with the concentration ratio of incident light. At the same time, the open-circuit voltage (V_oc) of solar cells increases logarithmically with the photocurrent. This leads to an increase in efficiency with increasing sunlight intensity.We proposed a novel hetero-junction structure microcrystalline silicon (μc-Si:H) solar cell structure using wide-gap microcrystalline silicon oxide (μc-Si_1 ? xO_x:H) as p-layer and it has some advantages over conventional homo-junction μc-Si:H solar cells under low concentrations. It was observed that wide-gap doped layers can reduce carrier recombination rate especially in p-layer and at the p/i interface and V_oc enhancement with increasing light intensity improves as the band gap of p-layer is increased. Our best solar cell has efficiencies of 9.2% at 1 sun and 10.4% at 11.8 suns. We also investigated the degradation behavior of hetero-junction μc-Si:H solar cells. The degradation in efficiency for this type of solar cell was less than 6%. Therefore, hetero-junction μc-Si:H solar cell is the promising alternative for low-light concentration.     

Chiral Symmetry Breaking of Spiropyrans and Spirooxazines by Dynamic Enantioselective Crystallization

Dynamic enantioselective crystallization enabled the chiral symmetry breaking of two spiropyrans and one spirooxazine. The three spiro compounds afforded racemic conglomerate crystals, and easily racemized in alcoholic solution without irradiation. Optically pure enantiomorphic crystals were obtained by vapor-diffusion crystallization or attrition-enhanced deracemization (Viedma ripening). Their absolute configurations were determined by single-crystal X-ray analysis and each enantiomorphic crystal was correlated with its solid-state circular dichroism (CD) spectrum.     

Asymmetric Synthesis of an Amino Acid Derivative from Achiral Aroyl Acrylamide by Reversible Michael Addition and Preferential Crystallization

Single‐handed α‐amino acid derivatives were generated from achiral precursors without an external chiral source. Conjugate addition of phenethylamine to an achiral aroyl acrylamide under homogeneous conditions gave the α‐amino amides in quantitative yields, which crystallized as a conglomerate of a P2₁ crystal system. Dynamic preferential crystallization or attrition‐enhanced deracemization resulted in the formation of enantiomorphic crystals of 99 % ee.     

Thermal polymerizations of alkali 4-(2-bromoethyl)benzoates in bulk

Thermal polymerizations of alkali 4-(2-bromoethyl)benzoates (2-BEBAs) were investigated. The polymerization of the lithium salt at 220°C for 2 h under reduced pressure in bulk, followed by esterification, produced poly(methyl 4-vinylbenzoate), having a number-average molecular weight (M̄_n) of 9500 in a 54% yield. Thus, elimination of hydrogen bromide to form a double bond occurred, followed by vinyl polymerization. In contrast, polymerization of the potassium salt at 200°C for 2 h afforded poly(oxycarbonyl-1,4-phenylene-ethylene) (polyester 1), having an inherent viscosity of 0.19 dL g⁻¹ in a 95% yield: i.e., polycondensation proceeded to afford the polyester. Reaction of the sodium salt at 220°C for 2 h produced polyester 1 having M̄_n of 4000 in a 28% yield as well as 4-vinylbenzoic acid in a 9% yield. In the reaction of the sodium salt, both polycondensation and double bond formation occurred. Thus, these polymerizations depended on the counter cations of 2-BEBAs. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2055–2060, 1999