bluuebunny/crossref_metadata_2025 huggingface dataset:
Creation of Double Silica Nanotubes by Using Crown‐Appended Cholesterol Nanotubes
Authors: Jung Jong Hwa , Lee Seok‐Hoon , Yoo Jong Shin , Yoshida Kaname , Shimizu Toshimi , Shinkai Seiji
Published: November 2003

New crown‐appended cholesterol‐based organogelators 1–3, which have one or two cholesterol skeletons as a chiral aggregate‐forming site, two amino groups as an acidic proton binding site, and one crown moiety as a cation binding site, were synthesized, and the gelation ability was evaluated in organic solvents. These gelators could gelatinize several organic solvents under 1.0 wt %, indicating that 1–3 act as a versatile gelator of various organic solvents. We observed CD spectra of the acetic acid or propionic acid gels of 1–3 to characterize the aggregation mode in the organogel system. In the CD spectrum of the acetic acid gel 1, the positive sign for the first Cotton effect indicates that the dipole moments of azobenzene chromophores tend to orient into the clockwise direction. On the other hand, propionic acid gels 2 and 3, bearing only one cholesterol, moiety exhibit a negative sign for the first Cotton effect, strongly suggesting that the dipole moments of the azobenzene chromophores orient into the anticlockwise direction. The TEM images of the 1+acetic acid gel resulted in the helical ribbon and tubular structures. Sol‐gel polycondensation of tetraethoxysilane (TEOS) was carried out with 1–3 as templates in the gel phase. The silica obtained from the 1+acetic acid gel showed the helical ribbon with 200–1700 nm width and the tubular structure of the silica with constant about 560 nm outer diameter. As far as can be recognized, all the helicity possesses a right‐handed helical motif. Since the exciton coupling band of the organogel also shows P (right‐handed) helicity, we consider that a microscopic helicity is reflected by a macroscopic helicity. On the other hand, the tubular structure of the silica obtained from the organogels 2 and 3 is somewhat different from that prepared from the organogel 1. The careful examination of SEM and TEM pictures revealed that the tube wall of the silica features a roll‐paper‐like multilayer structure. Thus, this paper demonstrates successful and rare examples for precise transcription of gel superstructures into inorganic silica materials.
Synthesis, Biochemical Properties and Molecular Modelling Studies of Organometallic Specific Estrogen Receptor Modulators (SERMs), the Ferrocifens and Hydroxyferrocifens: Evidence for an Antiproliferative Effect of Hydroxyferrocifens on both Hormone‐Dependent and Hormone‐Independent Breast Cancer Cell Lines
Authors: Top Siden , Vessières Anne , Leclercq Guy , Quivy Jacques , Tang J. , Vaissermann J. , Huché Michel , Jaouen Gérard
Published: November 2003

A series of ferrocene derivatives based upon the structure of the antiestrogenic drug tamoxifen or of its active metabolite hydroxytamoxifen has been prepared and named by analogy ferrocifens and hydroxyferrocifens. This series includes 1‐[4‐(O(CH2)nNMe2)phenyl]‐1‐phenyl‐2‐ferrocenyl‐but‐1‐ene and 1‐[4‐(O(CH2)nNMe2)phenyl]‐1‐(4‐hydroxyphenyl)‐2‐ferrocenyl‐but‐1‐ene, with n=2, 3, 5 and 8, and 1‐[4‐(O(CH2)2NMe2)phenyl]‐1‐(4‐hydroxyphenyl)‐2‐ferrocenylethene. Most of these molecules have been synthesised by McMurry cross‐coupling of the appropriate ketones, except for the ethene complexes, which were prepared by a four‐step reaction sequence starting from the ferrocenylacetic acid. All these compounds were obtained as mixtures of Z and E isomers. The isomers were separated in the cases of the ferrocenyl derivatives of tamoxifen and hydroxytamoxifen (n=2). No isomerisation of the Z and E isomers occurred in DMSO after one day, while a 50:50 mixture of the isomers was obtained within one hour in chloroform. The X‐ray structure of (E)‐1‐[4‐(O(CH2)2NMe2)phenyl]‐1‐(4‐hydroxyphenyl)‐2‐ferrocenyl‐but‐1‐ene has been determined. The relative binding affinity (RBA) values of the hydroxyferrocifens for the estrogen receptor alpha (ERα) was good to moderate, with values decreasing progressively with the length of the basic chain. The RBA values found for the estrogen receptor beta (ERβ) are equal to or slightly less than those found for the alpha form. The lipophilicity of the hydroxyferrocifens are superior to the values found for estradiol and increase with lengthening of the chain. The antiproliferative effects of the four hydroxyferrocifens with n=2, 3, 5 and 8 were studied on four breast cancer cell lines (MCF7, MDA‐MB231, RTx6 and TD5) possessing different levels of ERα. On MCF7 cells containing high levels of ERα, hydroxyferrocifens behave as antiestrogens. At a molarity of 1 μM the effect is close to that of hydroxytamoxifen (used for reference) when n=2 or 5, more marked when n=3, and weaker when n=8. Ferrocene alone has no effect. For the MDA‐MB231 cells, classed as a hormone‐independent breast cancer cell line, on the other hand, the hydroxyferrocifens show remarkable antiproliferative behaviour while the hydroxytamoxifen is completely inactive. Hydroxyferrocifens therefore show the unique property of being active both on hormone‐dependent and on hormone‐independent breast cancer cell lines. The molecular modelling study provides some clues for understanding of the antagonist effect of these molecules, while an additional cytotoxic effect due to the vectorised ferrocenyl unit is revealed in some occasions.
Mild Synthesis of Polyfunctional Benzimidazoles and Indoles by the Reduction of Functionalized Nitroarenes with Phenylmagnesium Chloride
Authors: Dohle Wolfgang , Staubitz Anne , Knochel Paul
Published: November 2003

Phenylmagnesium chloride has been used for the conversion of selected nitroarenes into nitrenes. Their insertion into a neighboring sp2 CH bond yielded functionalized heterocycles. A novel and mild synthesis of polyfunctional benzimidazoles and indoles is described.
Dimethylsulfoxide as a Ligand for RhI and IrI Complexes—Isolation, Structure, and Reactivity Towards XH Bonds (X=H, OH, OCH3)
Authors: Dorta Reto , Rozenberg Haim , Shimon Linda J. W. , Milstein David
Published: November 2003

Novel neutral and cationic RhI and IrI complexes that contain only DMSO molecules as dative ligands with S‐, O‐, and bridging S,O‐binding modes were isolated and characterized. The neutral derivatives [RhCl(DMSO)3] (1) and [IrCl(DMSO)3] (2) were synthesized from the dimeric precursors [M2Cl2(coe)4] (M=Rh, Ir; COE=cyclooctene). The dimeric IrI compound [Ir2Cl2(DMSO)4] (3) was obtained from 2. The first example of a square‐planar complex with a bidentate S,O‐bridging DMSO ligand, [(coe)(DMSO)Rh(μ‐Cl)(μ‐DMSO)RhCl(DMSO)] (4), was obtained by treating [Rh2Cl2(coe)4] with three equivalents of DMSO. The mixed DMSO–olefin complex [IrCl(cod)(DMSO)] (5, COD=cyclooctadiene) was generated from [Ir2Cl2(cod)2]. Substitution reactions of these neutral systems afforded the complexes [RhCl(py)(DMSO)2] (6), [IrCl(py)(DMSO)2] (7), [IrCl(iPr3P)(DMSO)2] (8), [RhCl(dmbpy)(DMSO)] (9, dmbpy=4,4′‐dimethyl‐2,2′‐bipyridine), and [IrCl(dmbpy)(DMSO)] (10). The cationic O‐bound complex [Rh(cod)(DMSO)2]BF4 (11) was synthesized from [Rh(cod)2]BF4. Treatment of the cationic complexes [M(coe)2(OCMe2)2]PF6 (M=Rh, Ir) with DMSO gave the mixed S‐ and O‐bound DMSO complexes [M(DMSO)2(DMSO)2]PF6 (Rh=12; Ir=in situ characterization). Substitution of the O‐bound DMSO ligands with dmbpy or pyridine resulted in the isolation of [Rh(dmbpy)(DMSO)2]PF6 (13) and [Ir(py)2(DMSO)2]PF6 (14). Oxidative addition of hydrogen to [IrCl(DMSO)3] (2) gave the kinetic product fac‐[Ir(H)2Cl(DMSO)3] (15) which was then easily converted to the more thermodynamically stable product mer‐[Ir(H)2Cl(DMSO)3] (16). Oxidative addition of water to both neutral and cationic IrI DMSO complexes gave the corresponding hydrido–hydroxo addition products syn‐[(DMSO)2HIr(μ‐OH)2(μ‐Cl)IrH(DMSO)2][IrCl2(DMSO)2] (17) and anti‐[(DMSO)2(DMSO)HIr(μ‐OH)2IrH(DMSO)2(DMSO)][PF6]2 (18). The cationic [Ir(DMSO)2(DMSO)2]PF6 complex (formed in situ from [Ir(coe)2(OCMe2)2]PF6) also reacts with methanol to give the hydrido–alkoxo complex syn‐[(DMSO)2HIr(μ‐OCH3)3IrH(DMSO)2]PF6 (19). Complexes 1, 2, 4, 5, 11, 12, 14, 17, 18, and 19 were characterized by crystallography.
Including all children: finding out about the experiences of children with communication and/or cognitive impairments
Authors: Morris Jenny
Published: November 2003

Practitioners and researchers have made progress, in recent years, in seeking the views of children and young people. Less progress has been made in seeking the views of young people with significant communication and/or cognitive impairments. Drawing on the experience of three research projects and one Best Value review, this article details the lessons learnt, and action required, in order to find out about the experiences of this important group of children and young people. Copyright © 2003 John Wiley & Sons, Ltd.
‘Having a say’: children and young people talk about consultation
Authors: Stafford Anne , Laybourn Ann , Hill Malcolm , Walker Moira
Published: November 2003

There has been a recent surge of interest in consulting children and young people about issues affecting them. Research in this area can in the main be said to have been motivated by adult agenda, with little attempt to seek the views of children and young people themselves. This paper is based on what children have said about consultation. They were critical of some of the more widely used methods, largely because they saw them as unrepresentative. The main message from the research is that children want to be consulted if it is done properly, if it is about issues directly affecting them and if they see it as likely to yield results that are likely to benefit them or other young people. Copyright © 2003 John Wiley & Sons, Ltd.
Einsatz oberflächenaktiver Substanzen zur Verbesserung der biologischen Abbaubarkeit von Mineralölkohlenwasserstoffen
Authors: Martienssen M. , Reichel O. , Schirmer M.
Published: November 2003

No abstracts.
Mikroverkapselte Wirkstoffe und Mikrokugeln in pharmazeutischen und kosmetischen Anwendungen
Authors: Brandau T.
Published: November 2003

No abstracts.
Untersuchung der Partikelbildung bei der Dispersionspolymerisation von Methylmetharcylat in überkritischem Kohlendioxid mittels Turbidimetrie
Authors: Ballauff M. , Fehrenbacher U. , Hirth T.
Published: November 2003

No abstracts.
Entstaubung von Lichtbogenöfen in der Stahlindustrie
Authors: Kirschen M. , Velikorodov V. , Pfeifer H.
Published: November 2003

No abstracts.
Temperaturbeaufschlagung der Ausblaseleitungen von Sicherheitsventilen
Authors: Marquardt A.
Published: November 2003

No abstracts.
Der Einsatz von Keramikmembranen in der Fruchtsaftindustrie, verdeutlicht an Praxisbeispielen
Authors: Bolduan P. , Latz M.
Published: November 2003

No abstracts.
Hybridverfahren zur Trennung von Methanol/Isopropanol/Wasser‐Gemischen
Authors: Dijkstra M.F.J. , Bach S. , Brinkmann T. , Ebert K. , Ohlrogge K.
Published: November 2003

No abstracts.
Reversibilitätsnahe Absorption im gekühlten Gleichstromabsorber am Beispiel eines offenen Sorptionskreisprozesses
Authors: Steinbrück M. , Hebecker D.
Published: November 2003

No abstracts.
Spraykühlung als alternatives Kühlverfahren für heiße Metalle
Authors: Puschmann F. , Specht E.
Published: November 2003

No abstracts.
Wärmeübertragung bei der Verdampfung von Ammoniak in einem Plattenwärmeübertrager
Authors: André M. , Kabelac S. , De Vries B.
Published: November 2003

No abstracts.
Laserdiagnostische Untersuchung von Nanopartikeln
Authors: Bockhorn H. , Lehre T. , Hermle M. , Suntz R.
Published: November 2003

No abstracts.
Aerosolbildung in Kondensatoren
Authors: Mall‐Gleißle S.E. , Schaber K.
Published: November 2003

No abstracts.
Membranverfahren in der Erdgasaufbereitung
Authors: Brinkmann T. , Wind J. , Ohlrogge K.
Published: November 2003

No abstracts.
Membranen für Polymerelektrolyt‐Brennstoffzellen
Authors: Glüsen A. , Stolten D.
Published: November 2003

Die Polymerelektrolyt‐Membran ist das Herzstück von wasserstoffbetriebenen Polymerelektrolyt‐Brennstoffzellen (PEFC) und methanolbetriebenen Direktmethanol‐Brennstoffzellen (DMFC). Membranen aus sulfonierten Fluoropolymeren sind derzeit kommerziell erhältlich. Wichtige Forschungs‐ und Entwicklungsziele sind derzeit für die PEFC die Erhöhung der Betriebstemperatur, ohne die Membran zusätzlich befeuchten zu müssen, und für die DMFC die Verringerung des Methanoltransportes durch die Membran. Zusätzlich sollen durch die Verwendung fluorfreier Polymere die Kosten der Membran und die Umweltbelastung reduziert werden. Dabei spielen bereits in der industriellen Entwicklung befindliche Membranen ebenso eine Rolle wie neue Membrankonzepte aus der Grundlagenforschung.
Application of Gas Permeation in Fuel Cell Powered Vehicles
Authors: Klinkhammer B. , Matthias C. , Melin T.
Published: November 2003

Main motivation for the use of a polymer electrolyte membrane fuel cell (PEMFC) in traffic applications is its significant higher vehicle efficiency compared to internal combustion engines (ICE) especially under low‐load operation. Hydrogen is the ideal fuel for PEMFCs as it yields the highest level of fuel cell performance. Three different applications for gas permeation inside a fuel cell system have been investigated: water recovery, hydrogen purification, and oxygen enrichment. The focus was on the analysis of the technical feasibility and the availability of capable membranes on the pilot‐scale size for each application.
Polymeric Membranes for Medical Applications
Authors: Krause B. , Storr M. , Ertl T. , Buck R. , Hildwein H. , Deppisch R. , Göhl H.
Published: November 2003

The commercial application of membranes in dialysis treatment has started already 40 years ago. Today, dialysis is the application in medicine using the largest number of membrane surface area per year. Integration of the membrane production process into dialyzer manufacturing was the key element in the successful transition from small scale production to large scale dialyzer manufacturing. Automatization techniques are heavily integrated into this process to fulfill the high quality and safety demands in medical technology. This paper gives an overview on the different membrane applications in medical industry. The material selection for manufacturing dialysis membranes and the different membrane morphologies are discussed. In the second part the different manufacturing steps in dialyzer production are presented.
Magneto‐Optical Studies of HgTe/HgxCd1−xTe(S) Core–Shell Nanocrystals
Authors: Fradkin Leonid , Langof Lidia , Lifshitz Efrat , Rogach Andrey , Gaponik Nikolai , Weller Horst , Eychmüller Alex
Published: November 2003

The synthesis and magneto‐optical properties of HgTe nanocrystals capped with HgxCd1−xTe(S) alloyed shells have been investigated. The magneto‐optical measurements included the use of optically detected magnetic resonance (ODMR) and circular polarized photoluminescence (CP‐PL) spectroscopy. The PL spectra suggest the existence of luminescence events from both the core HgTe and the HgxCd1−xTe(S) shells. The continuous‐wave (cw) and time‐resolved ODMR measurements revealed that the luminescence at the shell regime is associated with a trap‐to‐band recombination emission. The electron trap is comprised of a Cd–Hg mixed site, confirming the existence of an alloyed HgxCd1−xTe(S) composition. The ODMR data and the CP‐PL measurements together revealed the g‐values of the trapped electron and the valence band hole.
Electrochemical Probing of Photochemical Reactions Inside Femtolitre Droplets Confined to Electrodes
Authors: Wadhawan Jay D. , Wain Andrew J. , Compton Richard G.
Published: November 2003

Random ensembles of femtolitre‐volume droplets containing redox active, photosensitive compounds immobilised on an electrode substrate permit photoelectrochemical studies within femtometric environments. Two chemical systems are described; the first is the N,N,N′,N′‐tetrahexyl‐para‐phenylenediamine redox‐catalysed photochemical debromination of the anaesthetic reagent halothane; the second is the photoinduced electron transfer from excited chlorophyll a to vitamin K1, which has possible potential in the development of solar cells based on photosynthesis.
Radical Ions from 3,3′′′,3′′′″‐Tris(butylsulfanyl)‐2,2′:5′,2″:5″,2′′′,5′′′,2′′′′:5′′′′,2′′′″‐sexithiophene: An Experimental and Theoretical Study of the p‐ and n‐Doped Oligomer
Authors: Alberti Angelo , Ballarin Barbara , Guerra Maurizio , Macciantelli Dante , Mucci Adele , Parenti Francesca , Schenetti Luisa , Seeber Renato , Zanardi Chiara
Published: November 2003

The 3,3′′′,3′′′″‐tris(butylsulfanyl)‐2,2′:5′,2″:5″,2′′′,5′′′,2′′′′:5′′′′,2′′′″‐sexithiophene 1 was investigated through spectroscopic (NMR, EPR, UV/Vis‐NIR), electrochemical, spectroelectrochemical and theoretical (DFT) studies. The charged species obtained upon its oxidation and reduction were characterised, showing that 1 can exist in at least five different oxidation states, that is, a neutral species, a radical cation, a dication, a radical anion, and a dianion. The long term stability of the radical cation 1+. was evidenced by the 1H NMR study in the presence of small quantities of trifluoroacetic acid (TFA). This approach allowed a comparison of the relative broadening of proton signals of 1, induced by the electron exchange process with traces of radical cation 1+., and the hfc (hyperfine coupling) constants obtained from the EPR study and DFT calculations. In the radical cation, all of the heterocyclic sulphur atoms are not significantly involved in the delocalisation of the unpaired electron, whereas the opposite holds for the radical anion. Time‐dependent DFT calculations reproduced well the wavelengths of the optical transitions observed in the spectroelectrochemical experiments for all the five oxidation states and support the formation of the dianion 12−.
Pressure assisted evolution of defects in silicon
Authors: Londos C. A. , Potsidi M. S. , Bak‐Misiuk J. , Misiuk A. , Emtsev V. V.
Published: November 2003

The effect of enhanced hydrostatic pressure following heat treatment on the evolution of point defects in neutron‐irradiated Czochralski‐grown silicon is investigated using infrared spectroscopy. The behavior of oxygen‐related defects, particularly of the VO and the VO2 centers, is mainly studied using samples subjected to heat treatment under hydrostatic pressure. It is observed that (1) pressure accelerates the annealing process of the VO defects and enhances the growth of the VO2 complexes and (2) the VO2 concentration is larger than expected from the corresponding decay of the VO defects. The faster decay of the VO defects is attributed to a pressure‐induced decrease of their migration energy. The larger VO2 concentration is also discussed. One possible explanation is that pressure stimulates an additional mechanism for the formation of the VO2 defects, which involves the reaction of oxygen dimers with vacancies. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical properties of Bi1.5ZnSb1.5O7 pyrochlore ceramics
Authors: Kayed T. S. , Mergen A.
Published: November 2003

Bi1.5ZnSb1.5O7 pyrochlore samples were prepared by solid state reaction method. They were examined by x‐ray diffraction and scanning electron microscopy. Single phase, belongs to the cubic pyrochlore structure, with a lattice parameter of 10.442 Å and grain size that varies from 16 to 20 μm was obtained. The electrical properties were measured at different temperatures in the range 15–330 K under different applied magnetic fields up 1.4 T. In our measurements for Hall coefficient, Hall resistivity, and mobility; we noticed an anomalous behavior at two temperatures (around 250 and 310 K) which was supported by the I‐V measurements (double transition of the slope of I‐V characteristics (β) at the same temperatures). This was discussed in terms of polarization phenomenon and mixed ionic‐electronic conduction. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A scheduling algorithm for packet delay differentiation
Authors: Mase Kenichi , Ohara Kazuhiro , Nogami Shinya , Karasawa Naoyuki
Published: November 2003

A scheduling algorithm called queue length control is proposed to ensure different quality in each of the traffic flows at a network node. This algorithm determines the control parameters (average queue length and its standard deviation) for a queue in advance (and off‐line) by using the M/G/1 model based on the delay target of each queue and then schedules based on these control parameters for each queue. A simulation compares this algorithm to other algorithms and demonstrates that the delay target of each traffic flow could be achieved over a broad range. When the control parameters are determined, although the actual packet length distribution and the packet arrival distribution are assumed to be different, a certain level of performance can be achieved. In other words, the presence of superior robust control characteristics is demonstrated. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(3): 87–97, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10008
A narrowband interference rejection technique for DS‐CDMA system
Authors: Kitano Toyokazu , Nabetani Toshihisa , Hara Shinsuke , Morinaga Norihiko
Published: November 2003

Due to congestion in wireless frequency use, it is difficult to assign an independent frequency bandwidth to broadband wireless communication systems based on the DS‐CDMA (Direct Sequence Code Division Multiple Access) system. Therefore, operation of the DS‐CDMA system on the existing narrowband wireless system is contemplated. However, the interference of the transmitted power of the existing narrowband wireless system on the DS‐CDMA system has not been studied. There is a possibility that significant narrowband interference on the DS‐CDMA system may occur. In this paper, a narrowband interference rejection system in DS‐CDMA is proposed. By making use of prior information on the carrier frequency of the narrowband interference, a narrowband interference rejection process with little computational overhead is realized. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(3): 74–86, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10076
A study on mutual coupling compensation method of array antennas
Authors: Inaba Takayuki , Sakamoto Teijiro , Miura Ryu , Oodo Masayuki , Araki Kiyomichi
Published: November 2003

Research and development have been carried out extensively on the MUSIC and ESPRIT algorithms, based on the eigenfunction expansion of the correlation matrix, for high‐resolution direction‐of‐arrival estimation using array antennas. A factor hindering the best performance of these high‐resolution algorithms in real array antennas is nonuniformity of the element patterns caused by element coupling in an array configuration. In this paper, it is assumed that the array antenna is operated in a single mode and that the initial deviations of the transmitted amplitude and phase of the feed system and errors such as interelement coupling can be represented by a single coupling matrix with complex elements. Under such assumptions, this paper proposes a method for compensating the error of the center of rotation of the rotating table on which the device under test for calibration data measurement is installed, and estimates the coupling matrix. By computer simulation in the case of a receiving array antenna, it is found that the coordinates of the rotating center and the coupling coefficient can be estimated and that received signals with the initial deviation and interelement coupling compensated can be obtained by multiplying by the inverse of the coupling matrix estimated for the received signals. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(3): 59–73, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10126
An adaptive media access control protocol and system performance of wireless ad hoc network using smart antenna
Authors: Ueda Tetsuro , Bandyopadhyay Somprakash , Hasuike Kazuo
Published: November 2003

A smart antenna can increase the number of simultaneous transmissions by reducing interference and improving the throughput performance. In this paper, we propose an adaptive media access control (MAC) protocol that periodically updates neighboring node information in a distributed network, such as a wireless ad hoc network, and uses smart antennas to achieve simultaneous communications by directionality control to neighboring nodes other than those currently communicating. We also verify that the overhead for updating the neighboring node information can be reduced to 15% or less than in conventional schemes and the number of simultaneous communications can be 2 to 3.5 times higher than when using omnidirectional antennas. Furthermore, we considered the effects of the overhead accompanying neighboring node updates, node density, beam width, and moving speed on the communication efficiency when using the proposed MAC protocol. The communication efficiency was improved by controlling the transmission power to shorten the transmission range, lower the node density, and widen the beam width more than by extending the transmission range and increasing the node density. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(3): 50–58, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10140
Analysis of radial line slot antennas with dielectric layers over the aperture
Authors: Miyachi Kensuke , Hirokawa Jiro , Ando Makoto
Published: November 2003

The slot coupling characteristics are analyzed and the aperture distributions are evaluated for several dielectric layers loaded on the upper surface outside the radial line slot antenna. First, for the design of a uniform aperture distribution, mutual coupling is expressed approximately by an infinite array of two‐dimensional slot pairs with equal‐amplitude excitation in a model with periodic boundary walls in the two directions of an external region. Based on this approximation, the slot length and the pair spacing in the radial direction are controlled so as to design an array with a uniform aperture distribution. Next, as a model effective for an arbitrary distribution over a finite aperture, a slot array that is finite in one dimension is analyzed by the spectral domain approach. Also, if the situation with dielectric loading through a gap such as a radome is considered, it is shown that the effect on the aperture distribution can be neglected if a dielectric layer with a thickness reducing the Fresnel reflection coefficient is placed about 1/8 wavelength away. The validity of the analysis and design is confirmed by trial fabrication and measurement at 38 GHz. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(3): 19–27, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10169
Error rate performance of multiple‐symbol differential detection over transmission channels with nonlinear amplification
Authors: Handa Shiro , Katase Yasuyuki , Sasamori Fumihito , Oshita Shinjiro
Published: November 2003

When efficient power amplification is considered in digital wireless communications, even the nonlinear region of an amplifier is used. In such cases, the symbol error rate deteriorates due to AM‐AM and AM‐PM distortion. This paper studies the spectral expansion, intersymbol interference, and symbol error rate when a nonlinear amplifier is used for transmission in a multivalued amplitude and phase modulation scheme. Multiple‐symbol differential detection using the RLS (Recursive Least Squares) algorithm is compared with coherent detection in order to eliminate the effect of nonlinear amplification and fading. The transmission characteristics when these detection methods are applied to transmission of the star QAM scheme in a white Gaussian noise channel and a Rayleigh fading channel are studied. It is confirmed that multiple‐symbol differential detection provides better symbol error rates than coherent detection. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(3): 1–10, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10183
Signal extension for orthogonal filter banks and its application to image coding
Authors: Uto Toshiyuki , Inoue Tomoya , Ikehara Masaaki
Published: November 2003

In this paper, a signal extension method is proposed for realization of nonextension convolution in a two‐channel orthogonal FIR filter bank. Methods of performing nonextension convolution include the symmetric extension method for a linear phase filter bank and the periodic extension method applicable to an arbitrary filter bank. However, the periodic extension method is not appropriate for image compression because it becomes discontinuous at the signal edge. In this paper, for application to an orthogonal filter bank, the input signal of the decomposed filter bank is extended in such a way that the input signal in the synthesized filter bank has symmetry similar to that in the symmetric extension method. In this way, nonextension convolution is realized. In this case, it is shown that there are degrees of freedom in the extension signals determined by the input signal and the coefficients of the decomposed filter bank. The extended signal is calculated by singularity decomposition in such a way that the extended signal becomes smooth. Finally, the proposed method is applied to the coding of static images and the effectiveness of the method is demonstrated. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(3): 41–48, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10125
Bifurcation structure of fractional harmonic entrainments in the forced Rayleigh oscillator
Authors: Sekikawa Munehisa , Inaba Naohiko , Yoshinaga Tetsuya , Kawakami Hiroshi
Published: November 2003

The bifurcation structure of fractional harmonic entrainments in the forced Rayleigh equation is analyzed in connection with the symmetry of the system. Due to the symmetry of the system, there are two types of fractional harmonic entrainment regions. One is the case in which an attractor symmetric in shape with respect to the origin is generated in the state space. Another is the case in which two attractors in an asymmetric shape appear in locations symmetric with respect to the origin. When the shapes of these bifurcation structures are studied on the parameter surface, it is found that the fractional harmonic entrainment regions of the two cases have different structures near the Neimark–Sacker bifurcation curve of the fundamental harmonic periodic solutions. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(3): 30–40, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10126
Constrained blind equalizer using adaptive nonlinear filter
Authors: Koizumi Ryo , Miyajima Teruyuki , Yamanaka Kazuo
Published: November 2003

In this paper, a new adaptive equalizer that adjusts the nonlinear filter without training signals is proposed and its performance is evaluated. In the proposed equalizer, the nonlinear filter has constraints, while learning is carried out by means of the output energy minimization algorithm. Since the proposed equalizer has nonlinearity, it has a better bit error rate than the linear equalizer. Further, since no training signal is needed, it is to be expected that the transmission efficiency is superior to that in an equalizer with training signals. In order to evaluate the performance limitations of the proposed equalizer, an optimum equalizer with constrained filter input is derived. By means of simulations, a performance evaluation is carried out and the effectiveness of the proposed equalizer is demonstrated. Further, in order to improve the performance of the proposed equalizer for a linear communication channel, an intersymbol interference canceler and an algorithm for correcting the error are proposed and their effectiveness is demonstrated. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(3): 17–29, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10145
A realization of transconductors based on an exponential circuit
Authors: Ishibashi Yukio , Hayashi Yugo , Ito Daisuke
Published: November 2003

This paper presents a transconductor configuration method based on an exponential circuit. First, the transconductor circuit configuration of the proposed method is described and its parameter values are presented, along with their theoretical transconductance values. Each parameter value in the proposed circuit can easily be derived by Taylor expansion of the output current. In this way, it is shown that the theoretical values of the linear input range of the proposed circuit are wider than those in the conventional cases. Next, a method of realization of the gain factor is described. Finally, the proposed method is confirmed by SPICE simulation. It is shown that the linear input range is close to the theoretical value. In addition, the total harmonic distortion (THD) and the noise characteristics are measured. Specifically, the proposed transconductor is shown to have good performance in noise. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(3): 10–16, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10146
q‐ary asymmetric error locating codes under the directional error model
Authors: Kiattichai Saowapa , Kaneko Haruhiko , Fujiwara Eiji
Published: November 2003

Character recognition systems, which employ a machine to recognize handwritten or printed characters, are prone to recognition errors in the cases of characters which are similar in shape. For example, the numerical character 7 is frequently mistaken for 9, and vice versa. In contrast, the characters 7 and 4 are not similar in shape, and 7 is unlikely to be mistaken for 4, or vice versa. Therefore, the rate of recognition error between these characters will be low. By considering this type of error model, this paper defines a new q‐ary asymmetric error and proposes a method for constructing single q‐ary asymmetric error locating codes. It also presents an evaluation of the code, demonstrating its superiority to the conventional single q‐ary symmetric error correcting code. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(3): 77–87, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1156
Mechanism of Reduction of 2,2‐Dibromomethyl‐1,3‐propanediol by NiI‐Tetraazamacrocyclic Complexes in Aqueous Solution − A Pulse Radiolysis and Electrochemical Study
Authors: Shandalov Elisabetha , Zilbermann Israel , Maimon Eric , Nahmani Yeoshua , Cohen Haim , Adar Eilon , Meyerstein Dan
Published: November 2003

The reduction, catalytic reduction and the electrocatalytic reduction of halo‐organic compounds are of major interest due to their role as pollutants. The mechanism and kinetics of reduction of 2,2‐dibromomethyl‐1,3‐propanediol by several NiI tetraazamacrocyclic complexes, (NiILi)+ (i = 1−4), in aqueous solutions to yield Br− and the non‐halogenated compound was studied using the pulse radiolysis technique. The rate constants k = 5.3 × 108, 1.6 × 107, 6.0 × 105 and 3.5 × 104 M−1s−1 for L1, L2, L3 and L4 respectively, of the reactions (NiILi)+ + RBr ⇄ (NiIILi)2+ + Br− + R· increase with the free‐energy gain in the reaction. All these complexes are good electrocatalysts for the reduction of this substrate. The mechanisms of the reductions is are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
A New Diazacyclooctane Dihydroxamate as a Siderophore Analogue − Synthesis and Equilibrium Studies of Iron(III) and Copper(II) Complexes
Authors: Gaspar Margarida , Telo J. Paulo , Santos M. Amélia
Published: November 2003

A new siderophore analogue based on the mesocyclic diamine 1,5‐diazacyclooctane (DACO) functionalized with two additional hydroxamate donor pendant groups, 1,5‐diazacyclooctane‐1,5‐bis(N‐methylacetohydroxamic acid) (DACODMAHA), has been synthesized from the corresponding diacetate derivative (DACODA). The complexation behaviour of this ligand towards CuII and FeIII in aqueous solution has been studied by potentiometry, UV/Vis and EPR spectroscopy and magnetic moment measurements. The CuII complexation involves the formation of a mononuclear species with a tetradentate mixed amine/hydroxamate coordination mode, whereas the FeIII complexation involves a binuclear species with Fe2L3 stoichiometry and normal {O,O}‐hydroxamate coordination mode. The redox potential of the iron complexes and the corresponding electron transfer mechanism are also evaluated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Design of Calixarene‐Type Ligands for Second Sphere Complexation of Noble Metal Ions
Authors: Belhamel Kamel , Nguyen T. K. Dzung , Benamor Mohamed , Ludwig Rainer
Published: November 2003

Macrocyclic ligands were designed according to the principle of ion recognition, synthesized and tested in their capability to extract AuIII. Different from other complexants which require ligand exchange prior to complexation, the reported ligands bind the complexes AuCl3 and AuCl4−. With a sufficiently sized macrocyclic cavity, hydrophobic calix[6]arenes derivatized at the “lower rim’ were employed for that purpose. Their ligating functionalities contain pyridino, amide or thioamide groups in order to achieve electron donor‐acceptor and electrostatic host‐guest interactions. We report the synthesis route and results on extraction, selectivity, kinetics and back‐extraction and compare with commercial extractants. Quantitative extraction from hydrochloric acid solutions was achieved as well as over 99% recovery in back‐extraction in one step each. Data on the selectivity over base metals, which are representative for the matrix in gold ores are provided. The ligands are powerful extractants for AuIII and show fast complexation kinetics. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Preparation, Photo‐luminescence and Electro‐Luminescence Behavior of Langmuir−Blodgett Films of Bipyridylrhenium(I) Surfactant Complexes
Authors: Yam Vivian Wing‐Wah , Li Bin , Yang Yu , Chu Ben Wai‐Kin , Wong Keith Man‐Chung , Cheung Kung‐Kai
Published: November 2003

Several bipyridylrhenium(I) surfactant complexes, fac‐[Re(CO)3(bpy)(L)]PF6 [bpy = 2,2′‐bipyridine, L = trans‐4‐dodecyloxy‐4′‐stilbazole (L1), trans‐4‐octadecyloxy‐4′‐stilbazole (L2), 4‐(4′‐dodecyloxyphenylethynyl)pyridine (L3)] were synthesized and characterised. The X‐ray crystal structure of fac‐[Re(CO)3(bpy)(L1)]PF6 has been determined. The complexes exhibited intense photo‐luminescence which has been ascribed to the dπ(Re) ⇄ π*(bpy) metal‐to‐ligand charge transfer (MLCT) triplet emission. The complexes were found to form stable Langmuir−Blodgett (LB) films with relatively high collapse pressures. The organic light‐emitting diodes (OLEDs) fabricated by employing the LB films of various complexes as the emitting layer exhibited electroluminescence (EL) behavior. The luminances of the EL devices were found to vary as a function of the number of LB film layers, hydrocarbon chain length and the deposition types. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis, Structure and Characterization of New Olivacine Derivatives and Their Platinum(II) Complexes
Authors: Romaniewska Anna , Jasztold‐Howorko Ryszard , Regiec Andrzej , Lis Tadeusz , Kuduk‐Jaworska Janina
Published: November 2003

Three unknown olivacine derivatives (L‐OCH3,L‐OH,L‐OAc) were synthesized according to a procedure that involves only a few steps, and used as ligands in the synthesis of neutral chelate platinum(II) complexes. The ligands, as well as their platinum complexes were spectroscopically characterized with IR,1H/13C NMR and UV/Vis spectroscopic techniques. The solid state structures of two ligands (L‐OCH3,L‐OAc) and one complex {[(L‐OCH3)PtCl2]} were determined by X‐ray diffraction. Molecular structure analysis of the ligands and the complex indicated that complexation resulted in a change in the conformation of the bipyridine fragment of the compounds studied and caused other interesting effects. Two crystallographically independent molecules of the complex were revealed in the measured crystal, with short intramolecular H···H distances. The structural and energetic aspects of the conformational behavior of the ligandL‐OCH3and the complex [(L‐OCH3)PtCl2] have been analyzed using semiempirical PM3 methods. In vitro antiproliferative activity was preliminarily estimated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
New [Ru3(CO)12]‐Based Catalysts with Imidazolinium Salt, Diimine, or Bis(oxazoline) Ligands and Ruthenium Bis(oxazoline) Complex for Tandem Isomerisation/Claisen Rearrangement of Dienyl Ethers − X‐ray Structure of [RuCl{(R,R)‐bis(isopropyloxazoline)}(p‐cymene)]BF4
Authors: Ben Ammar Hamed , Le Nôtre Jérôme , Salem Mansour , Kaddachi Mohamed T. , Toupet Loïc , Renaud Jean‐Luc , Bruneau Christian , Dixneuf Pierre H.
Published: November 2003

The reaction of various 1,7‐dienes in the presence of the three‐component catalyst A: [Ru3(CO)12]/imidazolinium salt/Cs2CO3 (1:1:2) leads to the tandem alkene isomerisation/Claisen rearrangement affording γ,δ‐unsaturated aldehydes. Other three component catalysts: [Ru3(CO)12]/diimine/Cs2CO3 and [Ru3(CO)12]/benzoxazoline or chiral bis(oxazoline)/Cs2CO3 offer new active catalytic systems for these tandem reactions. Two ruthenium complexes containing optically active bis(oxazoline), [RuCl{(R,R)‐bis(oxazoline)}(p‐cymene)]BF4, were prepared and the X‐ray structure of one of them (18) was established. The combination of chiral 18/imidazolinium salt/Cs2CO3 (1:1:2) catalysed the above reaction of 1,6‐dienes and the results suggest initial catalytic isomerisation followed by a thermal Claisen rearrangement. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
New AgI Organometallic Coordination Polymers and MII (M = CuII and CoII) Inorganic Supramolecular Complexes Generated from New Fulvene‐Type Ligands
Authors: Dong Yu‐Bin , Zhao Xia , Jin Guo‐Xia , Huang Ru‐Qi , Smith Mark D.
Published: November 2003

Two novel fulvene‐type organic ligands L1 and L2 have been synthesized by aroylation reaction of substituted cyclopentadienyl anions. L1 crystallized in the monoclinic space group P21, a = 6.7498(4), b = 20.5769(11), c = 8.9532(5) Å, β = 109.5060(10)°, and Z = 2. L2 crystallized in the triclinic space group P$\bar 1$
, a = 11.4126(10), b = 11.4763(10), c = 11.7719(10) Å, α = 67.050(2), β = 74.509(2), γ = 61.148(2)°, and Z = 2. The coordination chemistry of L1 and L2 has been investigated. One novel AgI‐containing organometallic coordination polymer 3, based on both AgI−C and AgI−N interactions, has been synthesized by combination of L1 and AgClO4 in a benzene/dichloromethane mixed‐solvent system. Two new MII‐containing [M = CuII (4) and CoII (5)] supramolecular complexes with seven‐membered metalla‐ring unit have been prepared by combination of L2 and the corresponding M(OAc)2·2H2O (M = CuII and CoII) salts in ethanol. The isostructural compounds 4 and 5 crystallized in the triclinic space group P$\bar 1$
[4: a = 8.8808(5), b = 10.9928(7), c = 14.2196(9) Å, α = 99.9750(10), β = 95.8190(10), γ = 93.5610(10)°, and Z = 1; 5: a = 8.7964(10), b = 10.8103(12), c = 14.3765(15) Å, α = 99.681(2), β = 95.930(2), γ = 93.429(2)°, and Z = 1]. In the solid state, molecular complexes 4 and 5 are bound by strong intermolecular N···O−H hydrogen bonds in a hand‐in‐hand fashion to give a novel one‐dimensional chain motif. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
X‐ray Crystal Structure and Electrical Conductivity of [Au(ppy)(C8H4S8)]2[PF6] [ppy− = C‐deprotonated 2‐phenylpyridine(−); C8H4S82− = 2‐{(4,5‐ethylenedithio)‐1,3‐dithiol‐2‐ylidene}‐1,3‐dithiole‐4,5‐dithionate(2−)]
Authors: Kubo Kazuya , Nakano Motohiro , Tamura Hatsue , Matsubayashi Gen‐etsu
Published: November 2003

Crystals of [Au(ppy)(C8H4S8)]2[PF6] [ppy− = C‐deprotonated 2‐phenylpyridine(−); C8H4S82− = 2‐{(4,5‐ethylenedithio)‐1,3‐dithiol‐2‐ylidene}‐1,3‐dithiole‐4,5‐dithiolate(2−)] were prepared by current‐controlled electrolysis of a benzonitrile solution of [Au(ppy)(C8H4S8)] with [NEt4][PF6] as an electrolyte. The X‐ray crystal structure analysis revealed the formation of a columnar stacking of two crystallographically independent cations in formally the 0.5‐electron‐oxidized state. Cation moieties with some S−S non‐bonded contacts (< 3.7 Å) along the a and b axes form a two‐dimensional sheet, with the molecular interaction parallel to the ab plane. The electrical conductivities measured for a crystal at room temperature were 9.2 and 0.0028 S cm−1 along the a and c axes, respectively. From the activation energy for the electron conduction determined by the conductivities measured for a compacted pellet the complex was estimated to be metallic from room temperature to 110 K. The energy‐band calculation for the oxidized species showed two‐dimensional electron conduction through the column. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Structural, Photophysical and Chiro‐Optical Properties of Lanthanide Complexes with a Bis(benzimidazole)pyridine‐Based Chiral Ligand
Authors: Muller Gilles , Maupin Christine L. , Riehl James P. , Birkedal Henrik , Piguet Claude , Bünzli Jean‐Claude G.
Published: November 2003

The neutral LnIII 1:1 nitrato complexes with the chiral ligand 2,6‐bis(1‐S‐neopentylbenzimidazol‐2‐yl)pyridine (L11) have been synthesised and their stability constants measured in acetonitrile (log K1 = 4.0−6.4). The crystal and molecular structure of [Eu(NO3)3(L11)(MeCN)] shows the typical meridional planar coordination of L11 to the metal ion and low symmetry of the coordination polyhedron. The influence of the steric hindrance generated by the substituent at R2 on the crystal packing and bond lengths is discussed. Photophysical measurements show that ligand L11 induces a 3ππ*‐to‐Ln energy‐transfer process in the EuIII complex, while the TbIII compound is ten times less luminescent. Addition of a second molecule of L11 to give [Ln(ClO4)2(L11)2]+ leads to a large quenching of the EuIII luminescence (140‐fold) due to several factors: a less efficient 1ππ*⇄3ππ* transfer (ca. fourfold), a smaller intrinsic quantum yield QEu (ca. threefold), and a substantially less efficient ligand‐to‐metal transfer (ca. 12‐fold). In the case of the TbIII complex, the decrease in the energy of the triplet state reduces further the TbIII emission through increased back transfer. The specific rotary dispersion of the 1:1 and 1:2 complexes points to the chirality of the complexes arising mainly from the ligand, while the circularly polarized luminescence of these complexes with EuIII and TbIII displays a weak effect, pointing to a small diastereomeric excess in solution. Altogether, this study demonstrates that electronic, thermodynamic and photophysical properties of lanthanide complexes with aromatic terdentate ligands can be tuned by modifying the number and the arrangement of the ligands, as well as their substituents, particularly those in the R2 and R3 positions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)