bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical Transport Properties of Perchlorate-Doped Oriented Polyacetylene
Authors: Miyamae Takayuki , Mori Takehiko , Seki Kazuhiko , Tanaka Jiro 
Published: July 2006

Abstract
The electrical conductivities of perchlorate-doped highly oriented polyacetylene films were measured from 290 to 1.5 K. The conductivity and its anisotropy were significantly enhanced by stretching. The value of the conductivity was 18000 S cm−1 at 190 K, and remained at 14000 S cm−1, even at 1.5 K. The extraordinary high conductivity at very low temperature showed that the film is really metallic. The temperature dependence of the conductivity could be expressed as the sum of two terms : One is almost a temperature-independent term, which may be due to a very weakly localized free carrier; the other is due to a three-dimensional variable-range hopping mechanism of a more localized carrier. The conduction mechanism is discussed in terms of the polson model of doped polyacetylene.
Properties of Hydrogel Membranes of Poly(vinyl alcohol) and Poly(acrylic acid) under a Pressure Gradient
Authors: Kiyono Ryotaro , Niimi Yoshiharu , Tasaka Masayasu 
Published: July 2006

Abstract
The dependence of the electric potential difference on time under a pressure gradient across hydrogel membranes, obtained by esterification of poly(vinyl alcohol) and poly(acrylic acid), was measured. At the moment when a pressure difference was applied, a sharp spike of the electric potential difference was observed. The overall variation of the electric potential difference on time consisted of two different processes. One of them, which gradually increased with time, and finally reached a steady-state value, reflects a relaxation of polymer chains dissolved in the liquid phase of the gel membrane under the pressure difference. The other, which showed a sharp inverse spike just after applying the pressure difference, and reached zero immediately, may have been caused by a transformation of the membrane matrix due to a sudden change in pressure before the migration of the water, that is, by compaction of the membrane matrix. When hydrogen molecules of the carboxyl groups in the gel membrane were exchanged with potassium ions, the gel membrane expanded. The relationship between the magnitude of the electric potential difference for each of the forms and the properties of the membranes is discussed.
Synthesis of N-Hydroxy-N-(o-chlorophenyl)-N′-(p-methoxyphenyl)benzamidine Hydrochloride and Its Reactions with Various Metal Ions
Authors: Tiwari Sushil Chandra , Sharma K N , Mohabey Hemlata 
Published: July 2006

Abstract
A new reagent N-hydroxy-N-(o-chlorophenyl)-N′-(p-methoxyphenyl)benzamidine hydrochloride, has been synthesized and is characterized on the basis of mp, elemental analysis, IR and UV spectra. The reactions of the reagent with metal ions suggest that new methods can be developed for gravimetric and extraction spectrophotometric determination of metal ions. The reagent has been successfully used for the extraction-spectrophotometric determination of vanadium(V) in presence of phenol. Many common ions including Co2+, Zn2+, Ag+, Mn2+, etc. do not interfere in the determination. The method has been applied for the determination of vanadium in steel samples.
Preparation and NMR Spectra of Hexacoordinate Metal Complexes of Mono(N-ethylethanediamine) and Mono(N-benzylethanediamine) and Crystal Structure of [Co(NH3)4(N-benzylethanediamine)] (NO3)3·1.5H2O
Authors: Kurosaki Hiromasa , Koga Sayuri , Goto Masafumi 
Published: July 2006

Abstract
Mono N-ethylethanediamine and N-benzylethanediamine complexes of Co(III), Fe(II), and Fe(III) with four cyano or ammine groups were prepared. Their 1H NMR spectra were measured to determine the conformation of N-ethyl and N-benzyl groups. These N-alkyl groups take pseudo-equatorial orientation at the coordinated secondary amine. The most preferred conformation is that the methyl and phenyl groups are anti with respect to the central metal ions. The crystal structure parameters of [Co(NH3)4(N-benzylethanediamine)](NO3)3·1.5H2O were determined: P21, Z = 2, a = 8.639(3), b = 21.240(3), c = 10.897(2) Å, β = 94.11(1)°. The crystallographically independent Co complex cations had opposite absolute configuration around coordinated secondary amine sites and the benzyl groups are anti to the cobalt atom.
Cobalt(III) Complexes with [N6−nXn]-Type Ligands. VIII. Preparation and Properties of Isomers of the (Salicylaldoximato)(triethylenetetramine)cobalt(III) Complexes and Crystal Structure of cis-β1-(RS, SR)-[Co(salal)(trien)]Cl·(CH3COCH3)·2H2O
Authors: Toyota Eiko , Umakoshi Keisuke , Yamamoto Yoshihisa 
Published: July 2006

Abstract
The title complexes of cis-β1-(RR,SS)-, cis-β1-(RS,SR)-, cis-β2-(RR,SS)-, and cis-β2-(RS,SR)-[Co(A)(trien)]Cl·nH2O and cis-β1-(RR,SS)-, cis-β1-(RS,SR)-, and cis-β2-(RR,SS)-[Co(B)(trien)]Cl2 have been obtained from a reaction mixture of cis-α-[CoCl2(trien)]Cl, Ag2O, and salicylaldoxime (Chart 1).

Separations of the A- and B-type complexes, and of the geometrical isomers of cis-β1 and β2, as well as those of the diastereoisomers of (RR,SS) and (RS,SR) were attempted by using Dowex 50W-X2 column chromatography. The B-type complexes were obtaind from the reaction mixture of the corresponding A-type complexes and hydrochloric acid. The structure of cis-β1-(RS,SR)-[Co(A)(trien)]Cl·(CH3COCH3)·2H2O has been confirmed by an X-ray analysis. Crystal data: CoC16H33N5O5Cl, orthorhombic, Pb21a, a = 14.091(2), b = 22.385(3), c = 7.011(2) Å, V = 2211.5(6) Å3, Z = 4, and R = 0.076. A property between A- and B-type complexes has been compared in the IR, NMR spectra, and electric conductivity in aqueous solution; i.e., the CH=N streching vibrations (ca. 1590 cm−1) of A-type complexes have a lower wavenumber than those (ca. 1600 cm−1) of B-type complexes. The chemical shifts (δ = 148—150) of the CH=N carbon signal of A-type complexes are at a higher field than those (δ = 160—162) of B-type complexes in D2O. The chemical shifts (δ = 7.9—8.0) of the CH=N proton signal of A-type complexes are at a higher field than those (δ = 8.2—8.4) of B-type complexes in D2O. The electric conductivities in aqueous solutions of A- and B-type complexes were ca. 120 and ca. 220 S cm2 mol−1, respectively. The absorption spectra of cis-β-(RS,SR)-isomers and the corresponding (RR,SS)-isomers showed two peaks at around 350 and 540 nm and three peaks at around 350, 470, and 540 nm, respectively.
Multielement Determination of Rare Earth Elements by Liquid Chromatography/Inductively Coupled Plasma Atomic Emission Spectrometry
Authors: Sawatari Hideyuki , Asano Takaaki , Hu Xincheng , Saizuka Tomoo , Itoh Akihide , Hirose Akio , Haraguchi Hiroki 
Published: July 2006

Abstract
The rapid determination of rare earth elements (REEs) has been investigated by an on-line system of high performance liquid chromatography/multichannel inductively coupled plasma atomic emission spectrometry. In the present system, all REEs could be detected simultaneously in a single chromatographic measurement without spectral interferences. Utilizing a cation exchange column and 2-hydroxy-2-methylpropanoic acid aqueous solution as the mobile phase, the detection limits of 0.4—30 ng ml−1 for all REEs were obtained. The system was applied to the determination of REEs in geological standard rock samples and rare earth impurities in high purity rare earth oxides. The REEs in standard rocks could be determined by the present HPLC/ICP-AES system without pretreatment after acid digestion, although the detection limits were not sufficient for the analysis of rare earth oxides.
Photoisomerization and Photocyclization Reactions of 1-Styrylanthracene
Authors: Karatsu Takashi , Kitamura Akihide , Zeng Hualing , Arai Tatsuo , Sakuragi Hirochika , Tokumaru Katsumi 
Published: July 2006

Abstract
On triplet sensitization, 1-styrylanthracene (1SA) undergoes adiabatic cis → trans one-way isomerization (3c* → 3t*) similarly to 2-anthrylethylenes. However, upon direct irradiation, cis-1SA in the singlet excited state mostly undergoes cyclization to a dihydrophenanthrene-type product (DHP), 4a,4b-dihydrobenzo[b]chrysene, competing with an inefficient intersystem crossing to 3c* followed by one-way isomerization. The produced DHP, in deaerated benzene, is reverted to cis-1SA by a thermal (Ea = 14.9 kcal mol−1) or a photochemical pathway; however, under an oxygenated atmosphere DHP gives benzo[b]chrysene. A failure in the production of a cyclized product upon the excitation of trans-1SA shows that the isomerization really takes place in a one-way fashion.
Stilbene Dimer Radical Cations in the Radiolyses of Stilbenes and 1,2,3,4-Tetraphenylcyclobutanes
Authors: Tojo Sachiko , Morishima Kazuhiro , Ishida Akito , Majima Tetsuro , Takamuku Setsuo 
Published: July 2006

Abstract
The reaction of the stilbene radical cation formed by pulse radiolysis or γ-radiolyses is explained based on neutralization as well as the formation of a π-type stilbene dimer radical cation (π-St2+•), converting to the σ-type St2+• (σ-St2+•). The r-1,c-2,t-3,t-4-tetraphenylcyclobutane radical cation generated in a rigid matrix at 77 K which converted to σ-St2+• upon warming. Both r-1,c-2,t-3,t-4- and r-1,t-2,c-3,t-4-tetraphenylcyclobutane radical cations underwent photochemical cycloreversion to π-St2+• upon irradiation at wavelengths longer than 390 nm at 77 K, and converted to σ-St2+• upon warming. It is suggested that π-St2+• has overlapping arrangements of π-electrons, while σ-St2+• has radical and cation centers on the 1- and 4-positions of the C4 linkage.
Design, Synthesis, and Characterization of Carbon Nanotube Solubilizers Carrying a Reactive Group
Authors: Narimatsu Kaori , Nishioka Junichi , Murakami Hiroto , Nakashima Naotoshi 
Published: July 2006

Abstract
We describe the design of new carbon nanotube (CNT) solubilizers based on a novel concept, that is, “reactive carbon nanotube solubilizers” that are compounds carrying a reactive moiety for the introduction of the desired functional groups.
Preliminary Study on Cogeneration of Carbon Nanotubes and C2 Hydrocarbon in CH4/H2 Corona Discharge
Authors: Yu Kailu , Ruan Guoling , Ben Yuheng , Zou Jijun 
Published: July 2006

Abstract
La-doped carbon nanotubes and valuable C2 hydrocarbon (C2H2 and C2H4) are simultaneously generated in CH4/H2 corona discharge. The analysis of off gas indicates that the addition of anodic alumina membrane shows no influence on plasma methane conversion reactions.
Synthesis of 1D Nanorutile (α-TiO2) by Interfacially Initiating Redox Reaction at Low Temperature
Authors: Li Xuebing , Liu Yankuan , Li Tanwei , Zhang Zude 
Published: July 2006

Abstract
One-dimensional nanorutile crystals have been synthesized by interfacially initiating redox reaction between titanium trichloride (TiCl3) and benzoyl peroxide (BPO) in a hydrothermal way at a relatively low temperature. It not only produced a large quantity of rutile nanorods but also provided a novel method to synthesize 1D nanomaterials at low temperature.
Dramatic Effects of the Substituents on the Solid-state Fluorescence Properties of Structural Isomers of Novel Benzofuro[2,3-c]oxazolocarbazole-type Fluorophores
Authors: Ooyama Yousuke , Harima Yutaka 
Published: July 2006

Abstract
Structural isomers of novel benzofuro[2,3-c]oxazolocarbazole-type fluorophores have been synthesized and their photophysical properties in solution and in the solid state were investigated; remarkable differences in the absorption and fluorescence spectra were observed between structural isomers in both states, and a drastic solid-state fluorescence enhancement was found to be caused by N-alkylation of fluorophores.
An Improved Volume Measurement for Determining Soil Water Retention Curves
Authors: Péron H , Hueckel T , Laloui L 
Published: July 2006

Abstract
The complete determination of soil water retention curves requires the sample volume to be measured in order to calculate its void ratio and degree of saturation. During drying in the pressure plate apparatus, cracks often appear in the sample altering its deformation and evaporation patterns. Consequently, this causes a significant scatter in the volume measurement when using the volume displacement method. This paper proposes a simple method to avoid cracking, by limiting friction and adhesion boundary effects, to allow for unrestrained shrinkage of the sample. Such modification of the technique decreases the measurement error by a factor of three.
Experimental Measurement of Selected Snowboard Mechanical Properties
Authors: Grewal D , Lund C , Rossetter E 
Published: July 2006

Abstract
Snowboard manufacturers attempt to design boards with mechanical properties that provide desirable ride and handling characteristics, adequate strength, and low manufacturing costs. Snowboards are typically a sandwich composite of several individual layers that vary significantly in geometry and composition. To better understand the influence of core materials and construction on a board's stiffness, ultimate failure load, and stored energy, several commercially available snowboards were tested to failure in three point bending. A series of representative boards were tested with three different core materials: foam, wood, and honeycomb. The results show that stiffness and ultimate failure load are most strongly influenced by the core wrap thickness, while the energy storage is most strongly influenced by the core material and construction method used.
Uniqueness polynomials for entire curves into complex projective space
Authors: Tan Tran Van 
Published: July 2006

SummaryIn this article we find a new class of uniqueness polynomials for entire curves into complex projective space. Moreover, we also prove that the zero set of every polynomial in the above-mentioned class is a hyperbolic hypersurface in the sense of Kobayashi and has the arithmetic finiteness property.
Removal of Nitrogen and Phosphorus Compounds in Biological Treatment of Municipal Wastewater in Israel
Authors: Brenner Asher 
Published: July 2006

AbstractIn Israel, the water shortage, on the one hand, and the concern for water resource quality on the other, have led to the awareness that a national wastewater reclamation program must be developed. Such a program could cover a major part of the agricultural water demand, and may enable disposal of effluents without any health hazard or environmental nuisance. Recent regulations issued by the Ministry of the Environment and by The Water Commission require stringent quality standards for treated wastewater destined for agricultural irrigation or for disposal into rivers. These include the requirement to apply processes for nitrogen removal (nitrification—denitrification) and for phosphorus removal. In Israel, there is only limited experience in the application of biological wastewater treatment processes for nitrification and denitrification. Treatment plants designed for nitrogen removal (such as the Shafdan and Netanya treatment plants) have demonstrated partial success only. Moreover, the requirement for phosphorus removal has not been studied or applied in Israel. It is therefore necessary to study and develop proper guidelines for nitrogen and phosphorus removal for municipal wastewater treatment in Israel. Pioneering results supported by a sophisticated mathematical model were obtained in this study. It has been shown that N and P removal can be easily achieved in Activated Sludge systems if designed and operated properly. Interpretation of results and their analysis for design purposes require the use of a mathematical model.
Photocatalysis by Composite Particles Containing Inert Domains
Authors: Avraham‐Shinman Arit , Paz Yaron 
Published: July 2006

AbstractTitanium dioxide is a well‐known photocatalyst for the treatment of air and water. The use of structures comprised of photocatalytic sites and high capacity adsorption sites may improve the TiO2 photoefficiency, in cases where the contaminnants do not adsorb well onto the photocatalyst. In this work, composite particles composed of activated carbon, partially coated with sol‐gel‐made titanium dioxide, were prepared and characterized. It was found that chelating the titanium tetraiso‐propoxide, used as a precursor, with acetylacetone is crucial for obtaining reasonable loading (up to 12–15% in weight). High content of water or humidity tends to form thick films that might bridge over the pores of the activated carbon, thus reducing the available surface area.The photocatalytic activity of the composite particles was tested by following the rate of production of carbon dioxide during the photodegradation of Rhodamine 6G in an aqueous solution. Enhanced mineralization rates relative to sol‐gel‐made titanium dioxide particles (by ˜30%) were observed. This enhancement is attributed to the adsorption of the contaminants in the vicinity of the photoactive sites. It was further found that the composite particles produced relatively less of the toxic by‐product carbon monoxide, than sol‐gel‐made titanium dioxide or the commercially available Degussa P25. The reason for this effect is yet to be determined.
Hydrodenitrification with PdCu Catalysts: Catalyst Optimization by Experimental and Quantum Chemical Approaches
Authors: Efremenko Irena , Matatov‐Meytal Uri , Sheintuch Moshe 
Published: July 2006

AbstractA continuous process for nitrate and nitrite abatement from drinking water by catalytic hydrogenation has been developed in our lab. We describe the experimental process development procedure, and support it with semiempirical quantum chemical methods. Comparisons of activated carbon (ACC) and silica glass fiber (GFC) cloths as supports for mono‐ and bimetallic Pd‐Cu catalysts show the former to be 45‐fold and 15‐fold more active for nitrite and nitrate hydrogenation, respectively, than the latter. Catalysts prepared by selective deposition of Cu on Pd/ACC led to better activity for nitrate hydrogenation than catalysts prepared by co‐impregnation or ion exchange methods. The optimal Cu:Pd atomic ratio was found to be 1:2. The computational results show the following: (i) The dispersion of Pd catalysts supported on ACC is much higher than that on GFC due to the larger surface area and higher density of adsorption sites, and that accounts for the higher activity of PdCu/ACC; (ii) Nanosized Pd particles supported on ACC have a semispherical shape and possess preferentially close‐packed triangular surfaces, while Pd/GFC particles are extended in the direction parallel to the support surface and show both fcc (100) and (111) planes; (iii) The interaction of Cu atoms with both supports is stronger than that of Pd; adsorbed Cu atoms show a greater ability to form monometallic than bimetallic bonds and that should result in poor mixing of the metal upon co‐impregnation, as was observed experimentally; (iv) Cu atoms in bimetallic PdCu particles admit a significant positive charge; the experimentally measured solubility of metal atoms correlates with their calculated charges.The best catalyst (2 wt%Pd‐0.6 wt%Cu/ACC) was employed in a novel continuous flow reactor for nitrate hydrogenation in distilled and tap water. The advantages of the reactor investigated over a conventional packed bed reactor are discussed, suggesting a potential for further process intensification.
High Nitrification Rate at Low pH in a Fluidized Bed Reactor with either Chalk or Sintered Glass as the Biofilm Carrier
Authors: Green Michal , Beliavski Michael , Denekamp Nadav , Gieseke Armin , De Beer Dirk , Tarre Sheldon 
Published: July 2006

AbstractA nitrification process using a fluidized bed reactor with chalk (solid calcium carbonate) as the biomass carrier and the only buffer agent was studied. The pH established in the reactor varied between 4.5 to 5.5, with lower pH obtained at higher nitrification rates. In spite of the low pH, high rate nitrification was observed with the nitrification kinetic parameters in the chalk reactor similar to those of biological reactors operating at pH > 7. Results from microsensor measurements refuted the possibility that favorable pH micro‐conditions prevailed on the chalk particles and contributed to high reactor performance. In addition, identification of the major bacterial species in the low pH chalk reactors revealed well‐known nitrifying bacteria. Based on these results, the performance of a fluidized bed reactor with porous sintered glass particles as the carrier for the biofilm (instead of chalk particles) was tested at similar low pH for comparison purposes. In contrast to the common knowledge of the nitrifers high sensitivity to low pH, the results from the non‐chalk biofilm reactor showed that well‐known nitrifying bacteria have the ability to nitrify at a high rate at low pH in a biofilm reactor using an inert (sintered glass) carrier.
Sonolytic Destruction of Trihalomethanes by Ultrasonic Irradiation
Authors: Shemer Hilla , Narkis Nava 
Published: July 2006

AbstractUltrasonic irradiation was employed for the degradation of trihalomethanes (THMs) CHCl3, CHBrCl2, CHBr2Cl, CHBr3, and CHI3. The effects of various reaction and sonication conditions on the sonodegradation of THMs were examined and explained by the principles of sonochemistry. Batch experiments were conducted at an ultrasonic frequency of 20 kHz and power of 18.4 W. The sonodegradation rate of the THMs increased with increasing the solution temperature or the acoustic intensity, whereas aqueous solution pH, solute concentration up to 10 mg/L, and water quality did not affect the sonolytic destruction of the THMs. Ultrasonic removal of CHCl3, CHBrCl2, CHBr2Cl, and CHBr3 was not affected by the presence of other compounds as a mixture in the aqueous solution, while CHI3 sonolysis was enhanced. Hydrogen peroxide, nitrate, chloride, bromide, and iodide were identified and quantified as the reaction inorganic products. Degradation rates and efficiencies followed the decreasing order of: CHCl3 > CHBrCl2 > CHBr2Cl > CHBr3 > CHI3, while the electrical energy consumed per liter of contaminated aqueous solution treated was found to be in inverse order.
Toxins and Biologically Active Secondary Metabolites of Microcystis sp. isolated from Lake Kinneret
Authors: Beresovsky Dina , Hadas Ora , Livne Alex , Sukenik Assaf , Kaplan Aaron , Carmeli Shmuel 
Published: July 2006

AbstractFor many years cyanobacteria were considered a minor, negligible component of the phytoplankton population in Lake Kinneret (Sea of Galilee, Israel). However, during the last decade several new species invaded the lake and other, more common species were present more frequently and in higher concentrations. Recently, we isolated two Microcystis sp. strains from Lake Kinneret. Both produced an array of hepatotoxic microcystins. In a bioassay‐guided study we identified in exudates of one of the Microcystis strains (MB‐K) that allelopathic activity was attributed to a novel metabolite, microcarbonin A (1). Subsequently, two other novel metabolites, micropeptin KT946 (2) and anabaenopeptin KT864 (3), were isolated from the hydrophilic extract of the cultured (MB‐K) strain, based on their protease inhibition activity. Homo‐ and heteronuclear‐2D‐NMR techniques, as well as HRMS, determined the gross structure of the three compounds. The relative and absolute stereochemistry of 2 and 3 was deduced from a combination of spectral data and Marfey's method for HPLC.