Atomic emission spectrometric analysis of airborne particulate matter by direct nebulization of suspensions into the inductively-coupled plasma

A method is described for the rapid, direct emission spectrometric determination of iron in airborne particulate matter collected on polystyrene fiber filters using a conventional high-volume sampler and a Japanese low-volume sampler. The suspension prepared by dissolving the filter material in xylene was directly nebulized into the inductivelycoupled plasma excitation source. An ultrasonic immersion device was used for stirring purposes. Particles within the size range 0.1–100 μm in diameter are collected on the high-volume filters, while the largest particles on low-volume filters do not exceed 10 μm in diameter. The difference in the particle size composition entailed the use of a separate set of standard suspensions for each sample type. Standard suspensions for calibration were prepared from NBS SRM-1648 (urban particulates) as originally received and from its ground powder for high-volume and low-volume samples, respectively. The relative standard deviation was usually below 5%, which is acceptable for large-scale air pollution survey work. The possibility of determining other major and minor elements in airborne particulate matter was also examined.     

Oxidation of alcohols by active species generated by electrochemical oxidation of organosulfur compounds

Oxidation of secondary alcohols to ketones was accomplished by an indirect electrochemical method utilizing thioanisole as a catalytic electron carrier.     

Miscibility and gas permeability of poly(ethylene-co-5,4 mol% 3,5,5-trimethylhexyl methacrylate)-polydimethyl-siloxane blends

 Blends of poly(ethylene- co-5.4 mol% 3,5,5-trimethylhexyl methacrylate) (PE-TMHM) with poly(dimethylsiloxane) (PDMS) were prepared in the PDMS content range from 0 to 20%. The miscibility was studied for PE-TMHM–PDMS blends by DSC, dynamic mechanical and microscopic spectroscopy, and the gas permeability was measured for O₂, N₂ and CO₂ as function of PDMS content. PE-TMHM and PDMS were partially miscible with each other below 20 wt% of PDMS content. The permeability coefficients (P) for O₂, N₂ and CO₂ were increased by the blending of PDMS to PE-TMHM. The change of P for O₂ with PDMS content well reflected the partially miscible phase separation behavior. Received: 10 June 1996 Accepted: 14 August 1996     

Frequency Dependence of ESR in Pristine Trans-Polyacetylene: Line Width

We measured a frequency dependence of ESR line width in (CH)x and (CD)x at frequencies 5～9,500 MHz. From a detailed analysis we could independently deduce 1-D diffusion rate of electron spin (neutral soliton) D_‖ /c_‖ ², and the trapped spin concentration C between 200 and 340 K.     

Hydration states and metallic intercalation effects in dry DNA

Temperature dependence of the complex dielectric constant at 16.3 GHz has been measured on dry poly(dA)-poly(dT) DNA with Na⁺ counterions under different relative humidity (RH). The rotational motion of sole water dipoles hydrated in PO₂⁻ is detected at low RH, and the collective motion due to water network in major groove is successfully observed at high RH. From the infrared (IR) spectroscopy in dry DNA introducing metallic ions (M-DNA), the symmetric and antisymmetric stretching bands of PO₂⁻ distinctly depend on RH and type of metallic ions. The IR spectral change indicates that the monovalent ions (Li and Na) are arranged in PO₂⁻ though the divalent and trivalent ions connect to the base molecules.     

Preparation and characterization of two crystalline forms of 4-amino-5-chloro-2-methoxy-N-[(2S,4S)-1-ethyl-2-hydroxymethyl-4-pyrroli dinyl]benzamide (TKS159)

For 4-amino-5-chloro-2-methoxy-N-[(2S,4S)-1-ethyl-2-hydroxymethyl-4-pyrrolid inyl]benzamide (TKS159), two polymorphs, forms alpha and beta, were prepared and characterized by means of X-ray powder diffractometry, thermal analysis, infrared spectroscopy and 13C-NMR spectroscopy, both in the solution and solid phases. The X-ray powder diffraction analysis gave different patterns for forms alpha and beta. In the thermogravimetry and differential thermal analysis profiles, form beta exhibited characteristic endo- and exothermic peaks at 112.7 degrees C and 116.2 degrees C, respectively, due to the partial melting-induced phase transition to form alpha without accompanying weight loss, and these were followed by an additional endothermic peak at 138.2 degrees C due to fusion. For form alpha, only an endothermic peak at 137.8 degrees C due to fusion was observed. The IR spectroscopic analyses of forms alpha and beta gave different absorption bands assigned to N-H and O-H stretching, N-H bending, and C=O stretching vibrations. From the data obtained by thermal analysis, form alpha was shown to be thermodynamically more stable than form beta.     

Determination of stereochemistry of bacteriochlorophyll gF and 8(1)-hydroxy-chlorophyll aF from Heliobacterium modesticaldum

The reaction center complex of heliobacteria contains three kinds of chlorophyll pigments, bacteriochlorophyll gF (BChl gF), its 13(2)-epimer BChl gF' and 8(1)-hydroxy-chlorophyll aF (8(1)-OH-Chl aF). Because the full stereochemistry of these naturally occurring chlorophyllous pigments has remained unknown, we determined the stereochemistry of both BChl gF and 8(1)-OH-Chl aF extracted from Heliobacterium modesticaldum. The configurations of the specific functional groups at ring-B as well as those at ring-D and -E were investigated by use of nuclear Overhauser effect correlations in their 1H-NMR spectra and circular dichroism spectra, as well as by modified Mosher's method in their chemical modification: (1) E-configuration was confirmed for the 8-ethylidene group at ring-B in BChl gF, (2) R-configuration was identified for the 1-hydroxyethyl group at ring-B in 8(1)-OH-Chl aF and (3) 13(2)-(R)-, 17-(S)- and 18-(S)-configurations at ring-D and -E in both BChl gF and 8(1)-OH-Chl aF were confirmed. These stereochemistries enabled us to discuss their biosynthesis and to propose possible routes for preparation of ethylidene and 1-hydroxyethyl groups at the 8-position.     

Three-component photopolymers based on thermal crosslinking and acidolytic de-crosslinking of vinyl ether groups. 2. effects of acid components on photopolymer characteristics

The three-component photopolymers consisting of poly(p-hydroxystyrene) (PHS) or poly(styrene-co-acrylic acid) (PSA) as the binder polymer, 2,2-bis(4-(2-(vinyloxy)ethoxy)phenyl)propane (BPA-DEVE) or 1,1,1-tris(4-(2-(vinyloxy)ethoxy)phenyl)ethane (THPETEVE) as the crosslinking agent, and a photoacid generator were investigated with regard to their lithographic characteristics and thermal crosslinking reactivity because of the acidity of the acid component. The thermal crosslinking rate can be represented as the pseudo first-order reaction. The PSA copolymer with an acrylic acid unit has the higher crosslinking rate and sensitivity, and the lower activation energy. Under low baking temperatures at which crosslinking does not take place, dual-mode resist behavior is observed.     

Study of radical generated from coumarin dye-sensitized photo-initiator systems in high-speed photopolymer coating layers using laser flash photolysis

Radical generation from photoinitiation systems containing carbonylbiscoumarin dye with a radical-generating reagent, 3,3′-carbonylbis[7-(diethylamino)-2H-1-benzopyran-2-one] (KCD-DA), with 2,2′-bis(2-chloro-phenyl)-4,4′5,5′-tetraphenyl-1, 1′-bi-1H-imidazole (BI) in a poly(methyl methacrylate) film has been investigated by laser flash photolysis using a total reflection cell. Imidazolyl radical (Im·) was predominantly generated from carbonylbiscoumarin triplet-sensi-­tized decomposition of BI, the quantum yield, Φ^o_Im· of Im· at an infinite concentration of BI was measured, Φ^o_Im· = 1.3. The high quantum yield, Φ^o_Im·, implies an efficient KCD-DA triplet-sensitized photoinitiation system containing BI. Copyright © 1998 John Wiley & Sons, Ltd.