bluuebunny/crossref_metadata_2025 huggingface dataset:
Deformation of decagonal Al‐Cu‐Co single quasicrystals
Authors: Bogdanowicz W.
Published: April 2003

Deformation process of decagonal single quasicrystals of Al‐Cu‐Co alloy was studied by X‐ray topography and optical microscopy. The deformation was performed at elevated temperature (550°C) not higher than the temperature of disordering transformation of clusters inside anti‐phase domains (600°C). It was found that at a deformation of about 3–5% glide occurs only in the direction of ten‐fold symmetry axis in which the boundaries of anti‐phase domains are arranged. At a deformation of about 7–9% the samples cracked.
Study of surface morphology of electrochemically etched n‐Si (111) electrodes at different anodic potentials
Authors: Jakubowicz J.
Published: April 2003

Changes of n‐Si (111) silicon surface morphology after anodisation at different voltage conditions in dilute NH4F solutions were studied by AFM technique. The electrochemical etching was done with respect to current‐voltage (I‐V) characteristics. The Si surface was investigated at increasing and constant voltage conditions. The porous silicon was formed at potentials slightly anodic from the rest potential (from ‐0.6 V to 0.02 V). On the other hand silicon oxide formation and electropolishing occurs at higher anodic potentials. The sustained current oscillations take place in the Si electrode, at 6 V potential in dilute NH4F solution. The nature of oscillations was attributed to cyclic silicon oxide formation and its dissolution. The surface undergoes from smooth (before oscillation peak) to rough (little before top of the peak) during oscillation peak, and finally transforms to smooth at the bottom of the peak. It was confirmed by the roughness parameter.
Influence of nanocrystalization on magnetoelastic Villari effect in Fe73.5Nb3Cu1Si13.5B9 alloy
Authors: Szewczyk R. , Bienkowski A. , Kolano R.
Published: April 2003

The results of an investigation of the influence of thermal annealing on the magnetoelastic properties of Fe73.5Nb3Cu1Si13.5B9 soft magnetic alloy in both amorphous and nanocrystalline state are presented. A new method developed was used to apply uniform compressive stresses to the investigated ring core made of the alloy. The compressive stresses produced by external mechanical forces were applied perpendicularly to the direction of the magnetizing field. Due to the uniform distribution of stresses in the core brittle nanocrystalline alloys may be tested for stresses up to 10 MPa. The results revealed, that process of nanocrystallisation causes significant increase in the stress sensitivity of the Fe73.5Nb3Cu1Si13.5B9 alloy. Moreover the influence of stresses caused by external forces is more significant at relatively low values of the magnetizing field suggesting that these nanocrystalline soft magnetic materials are stress sensitive in the range of technical operation of inductive components based on such materials.
Photovoltage generation and fluorescence of charged tetraphenylporphyrins with dopa melanin
Authors: Hanyz I. , Wróbel D.
Published: April 2003

Positively charged tetra(4‐N,N,N,N‐ trimethylanilinium) porphyrin (TAP) and negatively charged tetrakis(4‐sulphonatophenyl) porphyrin (TPPS4) and their mixtures with dopa melanin in polyvinyl alcohol have been investigated. On the basis of the absorption and fluorescence spectra it has been established the formation of TAP–dopa melanin complex which fluorescence is quenched whereas TPPS4fluorescence behaviour is only slightly changed in the presence of dopa melanin. Photovoltaic effects and photocurrent generation in a photoelectrochemical cell consisting of a layer dye solutions sandwiched between the semiconducting and gold electrodes have been investigated. The dependence of photovoltage signal on excitation wavelength (photovoltage action spectrum), kinetics of photocurrent rise and decay in the second time scale have been presented. Electric parameters of the photoelectrochemical cell (conductivity and capacitance) with porphyrin dyes, dopa melanin and their mixtures in the dark and upon illumination have been estimated. It was shown that all investigated dyes are able to generate photosignal but the values of photocurrent generated depend on the dye used in the experiment and the presence or absence of dopa melanin.
Effect of melt composition on the electrical conductivity and IR absorption of CsLiB6O10 crystals
Authors: Hartmann E. , Péter Á. , Lengyel K. , Kovács L.
Published: April 2003

The dc conductivity of cesium lithium borate crystals grown from different melt composition has been studied in the 50 – 750 °C range. The temperature dependence of the electrical conductivity followed the Arrhenius law in most cases. The anisotropy of the electrical conductivity of crystals was rather small. The vibrational modes of water molecules present in the crystals were detected by infrared absorption technique. It was found that the intensity of the two OH stretching vibrational bands depends on the thermal history of the crystals, and, beside the two main water bands, some additional weak lines appear at –185 °C in the crystals with low Cs/B ratio.
Electrical properties of hydrogen‐implanted Si annealed under high hydrostatic pressure
Authors: Kaniewska M. , Misiuk A.
Published: April 2003

Czochralski p‐type Si: B was implanted with H2‐ions at energy of 130 keV and a dose of 4 × 1016 cm‐3. The specimens were annealed at 720 K/10 h in argon ambient under a hydrostatic pressure of 1.2 GPa. Reference specimens were annealed under atmospheric pressure. Schottky‐barrier diodes were fabricated and then capacitance‐voltage (C‐V) measurements and C‐V profiling in the temperature range 80‐370 K were performed to characterise the samples. It has been found that the implantation followed by high temperature annealing is effective in producing deep as well as shallow acceptor levels in the Si energy gap. The deep acceptor is a dominant defect that acts as a strong compensating centre in the n‐type material. The latter was formed as a result of a conversion of the initially p‐type material due to creating thermal donors (TDs) during heat treatment. Unusual properties in C‐V curves and complex carrier profiles were attributed to the presence of the deep‐level defect. Moreover, it has been found that the generation and thermal activation energy of TDs showed a substantial dependence on the hydrostatic pressure. It is interpreted that high‐pressure gives rise to thermal donors that are distinctly different from those that form during annealing under normal pressure.
Hydrogen implantation effect on optical properties of GaAs doping superlattices
Authors: Kunert H. W. , Dale D. , Hayes M. , Malherbe J. , Kononenko V. K. , Barnas J.
Published: April 2003

Experimental results on the response of GaAs doping superlattices to 1 MeV hydrogen implantation at the doses of 5×1016, 1×1017, and 5×1017 cm‐2 are presented. The samples were studied by means of photoluminescence and inelastic light scattering spectroscopy. Several new optically stable transitions above the effective energy band were observed. Structural changes were monitored by Raman spectroscopy. Possible origin of the new transitions is discussed. An attempt is also made to determine character of the tunable behavior of the parameters in as‐grown and treated superlattices.
Deep‐level defects induced by Ar‐ion beam etching in n‐type AlxGa1‐xAs grown by MBE
Authors: Kaniewska M. , Bożek J.
Published: April 2003

Results of the electrical study of the damage caused by Ar‐ion beam etching in MBE grown AlxGa1‐xAs : Si laser diode material are reported. This study has involved measurements of capacitance as a function of voltage and temperature as well as deep level transient spectroscopy measurements on Schottky‐barriers diodes. The Schottky contacts were fabricated conventionally by depositing Au in a vacuum onto the etched AlGaAs surface. For a reference the Schottky diodes of the best quality were produced in‐situ by evaporation of Al on the top of the epi‐layer at the end of the MBE growth run. On the basis of the results of a comparative study deep‐level defects related to the subsurface damaged layer have been recognised. Emission signatures as well as depth profiles of the defect concentration have been studied and analysed. Moreover, DLTS spectra revealed the presence of a well‐known DX(Si) centre and M‐type defect related level attributed to a vacancy and impurity complex. The presence of an additional deep‐level defect located in the lower half of the energy gap that was induced by dry etching is also suggested. An extra defect considered has the high enough concentration to disturb carrier spatial profiles and DX centre characteristics. It is suggested that it may be responsible for degradation effects in GaAs/AlGaAs heterostructure lasers, which fabricating involves dry etching.
Raman scattering study of ZnBeSe semiconducting mixed crystals
Authors: Szybowicz M. , Kozielski M. , Firszt F. , Łęgowski S. , Męczyńska H.
Published: April 2003

The results of a study of Raman scattering of Zn1‐xBexSe mixed crystals are reported. Raman measurements were performed for crystals with x = 0.12 and x = 0.25 Be at room temperature and liquid nitrogen temperature. From the Raman spectra the longitudinal optical and transverse optical modes which correspond to ZnSe‐like and BeSe‐like were distinguished. Theoretical calculations of frequencies of BeSe modes and force constants for Zn1‐xBexSe were also performed using modified random element isodisplacement model. It has been shown that the dependence of the phonon energy on temperature may be described by the modified Klemens model.
Raman selection rules in C46v hexagonal crystals: allowed combinations and overtones of vibrational modes in wurtzite GaN
Authors: Kunert H. W.
Published: April 2003

A discrete set of oscillators belongs to the critical points in the lattice vibration spectrum. The vibrational states of crystals are classified according to appropriate irreducible representations of the relevant wave vector space groups. Suitable space‐group selection rules are used to determine the active one and two phonon combinations and overtone processes in hexagonal structures. Experimental Raman spectra of the hexagonal C46v GaN are discussed in terms of the derived selection rules.
Elastic and nonlinear optical properties of lithium tetraborate
Authors: Kasprowicz D. , Kroupa J. , Majchrowski A. , Michalski E. , Drozdowski M. , Żmija J.
Published: April 2003

The elastic properties of lithium tetraborate Li2B4O7single crystals have been studied by Brillouin scattering method. Using this method the propagation of the acoustic waves in the [100], [001], [110] and [011] directions has been estimated. The nonlinear optical coefficientsd31andd33were measured using the Maker fringe technique. The temperature dependence of the nonlinear optical coefficientd31does not confirm an earlier report on the existence of a phase transition in the temperature range from room temperature to 600°C.
Growth and properties of LiGaX2 (X = S, Se, Te) single crystals for nonlinear optical applications in the mid‐IR
Authors: Isaenko L. , Yelisseyev A. , Lobanov S. , Titov A. , Petrov V. , Zondy J.‐J. , Krinitsin P. , Merkulov A. , Vedenyapin V. , Smirnova J.
Published: April 2003

Single crystals LiGaX2 (X = S, Se, Te) of optical quality were grown, with transparency ranges at 5 cm‐1 absorption level of 0.32‐11.6 μm, 0.37‐13.2 μm and 0.54‐14.2 μm, respectively. The first two, LiGaS2 and LiGaSe2, have a wurtzite‐type structure whereas LiGaTe2 is tetragonal (chalcopyrite lattice). The three refractive indices were measured in the whole transparency ranges of LiGaS2 and LiGaSe2 and na and nc were found to be very close (quasi‐uniaxial optical anisotropy) with a crosspoint at 6.5 μm (LiGaS2) and 8 μm (LiGaSe2). Sellmeier equations were fitted and phase‐matching conditions for second harmonic generation (SHG) were calculated: the 1.467‐11.72 μm spectral range for the fundamental is covered by LiGaS2 and LiGaSe2.
Transient and stable color centers in pure and Cu‐doped LiNbO3
Authors: Matkovskii A. , Potera P. , Sugak D. , Zhydachevskii Ya. , Pankratov V. , Millers D. , Grigorjeva L. , Pracka I. , Lukasiewicz T.
Published: April 2003

The present work is devoted to investigation of stable and transient color centers that are induced by radiation and temperature in pure and Cu‐doped LiNbO3 single crystals. The transient changes of absorption of the crystals induced by pulsed electron beam (E=0.25 MeV) are studied in 0‐5000 ns time range, as well as stable changes of absorption induced by reducing annealing and irradiation with γ‐quanta, high energy electrons or fast reactor neutrons.
Oxygen agglomeration and formation of oxygen‐related thermal donors in heat‐treated silicon
Authors: Emtsev V. V. , Ammerlaan C. A. J. , Emtsev V. V. , Oganesyan G. A. , Misiuk A. , Surma B. , Bukowski A. , Londos C. A. , Potsidi M. S.
Published: April 2003

The characteristic features of production processes of thermal donors in Czochralski grown silicon heat treated at T=450°C under hydrostatic pressures of about 1 GPa are studied. Two families of oxygen‐related donors are formed under compressive stress. The first one is the well‐known thermal double donors whose production rate is increased by a factor of five as compared with that observed at atmospheric pressure. Along with them, new thermal donors with similar energy states are also produced. This family was found to be a dominant contributor to the thermal donors formed under compressive stress. The features of formation processes of both kinds of thermal donors are briefly discussed.
Optical properties of an In0.22Ga0.78Sb/GaSb single quantum well
Authors: Kudrawiec R. , Bryja L. , Sęk G. , Ryczko K. , Misiewicz J. , Forchel A.
Published: April 2003

Optical properties of an In0.22Ga0.78Sb/GaSb single quantum well (SQW) have been investigated by photoluminescence (PL) and photoreflectance (PR). Two electron and heavy hole confined states, which had been expected from envelope function calculations, have been detected experimentally. Besides two allowed transitions (1HH‐1C and 2HH‐2C) also forbidden one (1HH‐2C) has been observed in PR. In PL experiment, which had been performed in broad excitation power (EP) range at different temperatures, the state filling effect has been investigated. At 10 K with the increase of EP density to 2 W/cm2 a linear dependence of integrated PL intensity has been observed. The character of the PL emission is excitonic and does not change with the increase of EP in that excitation range. Above the excitation density of 2 W/cm2 the in‐plane heating of the quantum well carriers occurs. With the increase of temperature the nature of recombination process changes from excitonic to free‐carrier recombination type. Above 60 K only the free‐carrier recombination take place and for high excitation power an emission from the excited state (2HH‐2C) emerges.
Magneto‐transport in single InGaAs quantum wells of different shapes
Authors: Tomaka G. , Sheregii E. M. , Kąkol T. , Strupiński W. , Jakieła R. , Kolek A. , Stadler A. , Mleczko K.
Published: April 2003

The magneto‐transport measurements in InGaAs/InAlAs quantum wells (QW) obtained by MOCVD technology on InP substrates, and known as High Electron Mobility Transistors, were performed at low temperatures of 0.4 ‐ 15 K and high magnetic fields up to 10 T (with the magnetic field induction B perpendicular to the plane of the well). Three kinds of structures were studied. The Shubnikov‐de Haas oscillations demonstrating the occupancy of two subbands were observed. In order to determine the energies of Landau levels in the QW subbands, we have used the Zawadzki‐Pfeffer quazi‐two‐band model. Good agreement between calculated Landau levels and Fermi level from one hand, and positions of the Shubnikovde Haas oscillations peaks from the other, enable us to determine the parameters of 2D electron gas in QW: effective mass and carrier density.
An exact performance model for the reserve channels CAC strategy at a bufferless network node
Authors: Deniz Dervis Z. , Mohamed Nagla O.
Published: April 2003

The reserve channels call admission control (CAC) strategy in which the total number of channels available at the node is divided into active and reserve channels is analysed. Two types of customers are assumed to exist: the narrowband type requiring bandwidth bn=1 channel and wideband type requiring bw⩾1 channels. The active channels are shared by all customer types while the reserve channels are allocated by a predefined rule. An exact matrix algorithmic solution technique is proposed that extends the previous results to the case of calls requiring bw⩾1 channels. Using the developed solution technique, the number of equations to be solved is decreased which reduces the solution time by more than half. The technique is applied to a sample case and performance results in terms of blocking probabilities for both types of calls as well as the mean server utilization are obtained. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of load distribution in path protection of MPLS
Authors: Kim Sook‐Yeon
Published: April 2003

We analyse and compare a protection mechanism based on load distribution with a typical protection mechanism in an multiprotocol label switching (MPLS) network. The protection mechanism based on load distribution is modelled as a fully shared mechanism (FSM) and the typical protection mechanism is a partially shared mechanism (PSM). By comparing the FSM and the PSM, we numerically analyse the effect of load distribution in path protection of MPLS. The comparison is based on numerical equations representing the relationship between service reliability and resource utilization. From the equations, we show that both the FSM and the PSM have a tradeoff between service reliability and resource utilization. In addition, we provide solutions for the FSM and the PSM to determine the amount of bandwidth occupied according to the requested service reliability. The comparison of the FSM and the PSM shows that the PSM cannot provide greater service reliability than the FSM under the same utilization. In addition, the PSM is not capable of accommodating greater resource utilization than the FSM for the same level of service reliability. However, an appropriate choice of the number of protection paths allows the PSM to provide the same level of service reliability as the FSM. The choice is the maximum among the possible numbers of protection paths of the PSM. In short, the typical protection mechanism is as good as the FSM in terms of service reliability and resource utilization even though the FSM is an attractive alternative to the typical protection mechanism. Copyright © 2003 John Wiley & Sons, Ltd.
Explicit TCP window adaptation in a shared memory architecture
Authors: Aweya James , Ouellette Michel , Montuno Delfin Y.
Published: April 2003

A multiple (priority) queueing system allows a network node to manage the queueing of packets in such a way that higher priority packets will always be served first, low priority packets will be discarded when the queue is full, and for same‐priority packets any interference between them will be prevented. This paper describes a TCP window control scheme for a shared memory device that has buffer memory logically organized into multiple queues. To handle changing queue traffic loads, the shared memory device uses a dynamic buffer threshold mechanism to allocate buffer space to the queues. The TCP window control scheme allows the receiver's advertised window size in ACK packets to be modified at the network queue in order to maintain the queue size at a computed dynamic threshold. Copyright © 2003 John Wiley & Sons, Ltd.
kW‐value of a photovoltaic power generation system evaluated from actual data on electricity demand and insolation
Authors: Kato Takeyoshi , Nagae Nobuhisa , Tabata Akimori , Yokomizu Yasunobu , Okamoto Tatsuki , Suzuoki Yasuo
Published: April 2003

This paper proposes a new method of evaluating the kW‐value of photovoltaic power generation systems (PV systems). This evaluation is based on actual insolation data, collected by the Japan Meteorological Agency at four locations in the Chubu area in Japan, and the actual electrical load data of the Chubu area in the 1990s. We selected specific days on which the daily peak load was relatively high. For the selected days, we estimated the average output of PV systems using the IEA's method for considering the temperature dependency of cell efficiency. Then, we calculated the reduction of the peak load ΔLp(d). The resultant ΔLp(d) was distributed in the range from 0.4 to 0.5 kW/kWp.

We evaluated the average value of the smallest ΔLp(d) as the kW‐value of PV systems. When the kW‐value was evaluated for the two or three days with the smallest ΔLp(d) among the selected 10 days for 1 year, the kW‐value of the PV systems was calculated to be about 30%. This was close to the value obtained by the conventional loss of load probability (LOLP) method. Our study evaluates the relationship between the kW‐value of PV systems and the number of days on which the insolation was low but the daily peak demand was relatively high. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 42–49, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10089
Design of a robust PWM power amplifier using approximate two‐degree‐of‐freedom integral‐type control
Authors: Higuchi Kohji , Nakano Kazushi , Araki Kuniya , Chino Fumiho
Published: April 2003

A method is proposed for designing a robust controller for PWM power amplifiers, which are widely used as amplifiers and power supplies. The main technical requirements imposed on PWM power amplifiers are linearity in a wide frequency range and a well‐damped fast dynamic response in the presence of extensive load and DC power supply variations. Therefore, in order to satisfy the design specifications, namely, linearity in a wide frequency range and no overshoots during transients, an approximate two‐degree‐of‐freedom integral control structure is proposed and a design procedure for the robust controller is discussed. It is shown by some simulations and experiments that the designed controller shows especially good dynamic performance and effective disturbance rejection in the presence of external disturbances, that is, load and power‐supply variations. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 68–77, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10102
A design of self‐tuning pole‐assignment control systems based on minimizing quadratic cost functions
Authors: Ohnishi Yoshihiro , Yamamoto Toru , Kaneda Masahiro
Published: April 2003

There are numerous studies of the design of self‐tuning control (STC) systems for linear nonminimum‐phase systems. A wide variety of existing methods on designing STC systems are conceptually classified into two groups. One is based on minimization of an error criterion, and the other on pole assignment of the closed‐loop system. On the other hand, in order to guarantee the tracking property for the reference signals, an internal model which corresponds to the reference signals must be inserted into the control system based on the internal model principle. However, the variance of the control error signal may become large on inserting the internal model, because stochastic noise may be amplified. In this paper, a design method for self‐tuning pole‐assignment control systems with internal models is proposed based on minimizing the linear quadratic cost function. The newly proposed control scheme has the feature that the variance of the stochastic noise in the control system is reduced owing to the minimum variance control scheme, and also the tracking property with respect to the reference signal is assured owing to the internal model. The proposed control scheme is numerically evaluated in some simulation examples. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 50–57, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10120
Fundamental study on location of a partial discharge source with a VHF‐UHF radio interferometer system
Authors: Kawada Masatake
Published: April 2003

The electromagnetic waves emitted from partial discharges (PD) due to material defects in high‐voltage electric power apparatus and facilities are broadband signals including VHF, UHF (Very High Frequency, Ultra High Frequency). A new VHF‐UHF radio interferometer system (VURIS) for locating PD source has been designed, constructed, and tested. The system is based on the idea of using the Fourier transform to extract the phase differences of different frequency components between a pair of received signals and computing the direction of the electromagnetic waves emitted from the PD source. It can be small in size, because UHF half‐wavelength dipole antennas are used to receive the electromagnetic waves and the baseline between the antennas is short. It requires fewer antennas to achieve equivalent angular resolution than a narrow‐band interferometer system, which requires multiple baselines corresponding to a few times the half‐wavelength of the observation frequency. Therefore, its use reduces operating time at the measurement site because it is not necessary to arrange many antennas at many positions. The indoor test results indicate that the system is able to estimate the arrival angle of electromagnetic waves emitted from PD sources. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 32–41, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10145
Changes in capacitance and dielectric dissipation factor of water‐treed XLPE with applied voltage
Authors: Ozaki Tamon , Ito Noriyuki , Nakamura Shuhei , Kawai Jiro
Published: April 2003

The capacitance C and dielectric dissipation factor tan δ of a water‐treed XLPE sheet sample have been measured under the application of 100 V or 1 kV at 60 Hz. The values of C and tan δ at 1 kV are much larger than those at 100 V. The value of tan δ gradually decreases with the length of exposure to a voltage of 1 kV. On the other hand, C is almost constant versus the exposure time. The results have been discussed on the basis of a model in which filling of channels interconnecting voids by water is taken into account. It has been found that the increase of C and tan δ is caused by the growth of the water‐filled channel region on the application of voltage. The gradual decrease in tan δ with the exposure time is explained by the change in the conductivity of the water‐filled channel region, as a result of which the relaxation time shifts to higher frequencies. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 12–20, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10160
Estimation of partial discharge onset characteristics in gases around a triple junction
Authors: Hara Masanori , Kurihara Takashi , Kozuru Susumu , Suehiro Junya , Hayashi Noriyuki
Published: April 2003

A new method of estimating partial discharge onset conditions in gases around a triple junction is proposed. The effectiveness of the method based on the Paschen curve and the potential distribution along the interface between a solid insulator and gas is confirmed experimentally in air at room temperature. The partial discharge onset conditions in air and SF6 gas under different pressures at room temperature and in cryogenic nitrogen and helium gases at saturation temperature and atmospheric pressure are estimated. The partial discharge intensity is discussed on the basis of the proposed method. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 1–11, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10175
A method for parametrized contingency‐constrained optimal power flow (PCCOPF)
Authors: Tanabe Ryuya , Tada Yasuyuki , Sekine Yasuji
Published: April 2003

This paper presents a method for Parametrized Contingency Constrained Optimal Power Flow (PCCOPF) whose formulation can discriminate unpreventable contingencies, determine the existence of feasible solutions for postcontingencies, and analyze the feasible solution for the contingencies in terms of static sense. The proposed formulation is based on parametrized contingency constraints in which each contingency parameter represents the achievement ratio of each selected contingency. In the formulation, not only parametrized contingency constraints are given by a set of equality constraints which is modified power flow equations, but also the objective is maximization of the sum of the achievement ratios of selected contingencies. Since contingency parameters are treated as decision variables in the proposed method, the information on unsolvability with respect to each contingency can be efficiently obtained. The feasibility and effectiveness of the proposed method are demonstrated on test problems with 4‐bus and 71‐bus systems. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 21–31, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10182
Nonlinear modeling of a permanent‐magnet induction machine
Authors: Fukami Tadashi , Nakagawa Kenichi , Hanaoka Ryoichi , Takata Shinzo , Miyamoto Toshio
Published: April 2003

This paper presents the nonlinear modeling of a permanent‐magnet induction machine (PMIM). The PMIM has a permanent‐magnet (PM) rotor that is free to rotate inside a squirrel‐cage rotor. The internal self‐excitation from this PM rotor allows the PMIM to operate at a higher power factor. Utilizing a duality between magnetic and electric circuits, an electrical equivalent circuit that can accurately include the nonlinearity of the excitation circuit is derived. Based on this equivalent circuit, a measuring method of circuit parameters and a calculation method of the steady‐state performance are explained. In addition, the generating characteristics of the PMIM in the grid‐connected mode are theoretically calculated to verify the validity of the derived equivalent circuit, and the results are confirmed through experiments. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 58–67, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10189
Combining Magnets and Dielectrics: Crystal Chemistry in the BaO−Fe2O3−TiO2 System
Authors: Siegrist Theo , Vanderah Terrell A.
Published: April 2003

Phases observed in the BaO−Fe2O3−TiO2 system are classified and described in terms of the framework of close‐packed {O,Ba/O} layers, with the transition metal atoms either in octahedral (titanium and iron) or in tetrahedral (iron only) sites. The resulting crystal chemistry features new combinations of structural features intermediate between the magnetic barium hexaferrites and the dielectric barium polytitanates, and thus gives rise to phases with potentially useful magnetic/dielectric properties. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Efficient Energy Transfer in Supramolecular, Hydrogen‐Bonded Polypyridylruthenium‐Osmium Complexes
Authors: Rau Sven , Schäfer Bernhard , Schebesta Sebastian , Grüßing André , Poppitz Wolfgang , Walther Dirk , Duati Marco , Browne Wesley R. , Vos Johannes G.
Published: April 2003

Hydrogen bond association between ruthenium bibenzimidazole and carboxylated polypyridylosmium complexes results in stable supramolecular aggregates. The determined stability constant of logK ≈︁ 6 ± 0.3 allows efficient energy transfer from the ruthenium to the osmium moiety. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The First Azaindatrane and Unprecedented Structural Features
Authors: Shutov Pavel L. , Karlov Sergey S. , Harms Klaus , Poleshchuk Oleg Kh. , Lorberth Jörg , Zaitseva Galina S.
Published: April 2003

The reaction between [In(NEt2)3]2 and N(CH2CH2NMeH)3 yields the N,N′,N′′‐trimethylazaindatrane dimer [N(CH2CH2NMe)3In]2 (1). The composition and structure of 1 were established by 1H and 13C NMR spectroscopy as well as by an X‐ray diffraction study. The X‐ray structure shows that both indium atoms are pentacoordinate, with widely differing In−N distances. The structural parameters of 1 were compared with those obtained from a computational study. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Sequential Nucleophilic−Electrophilic Reactions Selectively Produce Isomerically Pure Nona‐B‐Substituted o‐Carborane Derivatives
Authors: Barberà Gemma , Teixidor Francesc , Viñas Clara , Sillanpää Reijo , Kivekäs Raikko
Published: April 2003

Nine equal substituents on the intensively studied o‐carborane have been obtained for the first time by a combined nucleophilic‐electrophilic reaction sequence. Iodine and methyl groups have been introduced to prove the generality of the method. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
A Three‐Dimensional Framework of Novel Vanadium Clusters Bridged by [Ni(en)2]2+: Ni(en)3{VIV11VV5O38 Cl [Ni (en)2]3}·8.5H2O
Authors: Pan Cheng‐Ling , Xu Ji‐Qing , Li Guang‐Hua , Chu De‐Qing , Wang Tie‐Gang
Published: April 2003

The hydrothermal reaction of V2O5, H2C2O4·2H2O, KOH, en and NiCl2·6H2O yields a new three‐dimensional open‐framework solid. The extended structure consists of a three‐dimensional network of [V16O38Cl]8− cages, with each cage connected to six other neighboring units through [Ni(en)2]2+ bridging groups. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
An Unusual Bonding Situation in a Novel AuI‐Phosphido Complex with a Planar Au3P3 Framework
Authors: Vogel Ulf , Sekar Perumal , Ahlrichs Reinhart , Huniar Uwe , Scheer Manfred
Published: April 2003

Reaction of the mono‐deprotonated derivative of [{Cp(CO)2Mo}2(μ‐PH2)(μ‐H)] (1) leads to the novel complex [{Cp(CO)2Mo}2(μ‐H){μ3‐P(H)Au(PPh3)}] (2). In contrast the reaction of the analogous Cr derivative [{Cp(CO)2Cr}2(μ‐PH2)(μ‐H)] (1a) leads under identical conditions to a planar Au3P3 cluster [{CpCr(CO)2}6(P3Au3)] (3). Both complexes were completely structurally and spectroscopically characterised. Density functional calculations have shown that 3 is characterised by P−Cr−Au multicentre and Cr‐P multiple bonding. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Self‐Assembly of Supramolecular Structures from Palladium Chloride and Guanidinium Salts of Pyridinecarboxylic Acids − A Dramatic Change on Passing from the para‐ to the meta‐Substituted Acid
Authors: Bacchi Alessia , Chiusoli Gian Paolo , Costa Mirco , Giacobbi Emmanuele
Published: April 2003

Supramolecular structures 1 and 2 were obtained in the solid state from the reaction between palladium chloride and guanidinium salts of p‐ and m‐pyridinecarboxylic acid, respectively. The pyridinecarboxylate anions were trans‐coordinated to palladium dichloride through nitrogen, and the carboxylate groups formed hydrogen bonds with guanidinium cations. The present paper describes a remarkable change in the stoichiometry and structural organization of the solid 3 derived from the meta‐substituted acid 2, triggered by the elimination of one guanidine molecule as hydrochloride per molecule of palladium chloride, during crystallization from methanol. The corresponding isonicotinate 1 structure appears to be stable under the same conditions. As shown by the analysis of the crystal structures, the guanidinium nicotinate organic salt 4 turns out to be preorganized to host palladium chloride both in 2 and 3. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Application of Gel‐Phase 195Pt NMR Spectroscopy in a Novel Solid‐Phase Synthesis of a Primary Amine Dichloroplatinum(II) Complex
Authors: Robillard Marc S. , Leith Jason S. , van der Marel Gijs A. , van Boom Jacques H. , Reedijk Jan
Published: April 2003

Gel‐phase 195Pt NMR spectroscopy of dichloroplatinum peptide complexes attached to a solid support is described. The observed 195Pt chemical shifts of the support‐bound platinum complexes are in good agreement with the solution‐state 195Pt NMR spectra of the soluble and deprotected analogs. This non‐destructive analytical method for on‐resin‐compound analysis was applied in the optimization of the solid‐phase synthesis of the primary amine dichloroplatinum complex 6, which represents a new class of platinum complexes now available via solid‐phase synthetic chemistry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Metal‐Promoted Cage Rearrangements in the Tricarbollide Series: Conversion of Ligand Derivatives 7‐L‐nido‐7,8,9‐C3B8H10 (L = H3N, tBuH2N, Me2HN) into Neutral 8‐R‐nido‐7,8,9‐C3B8H11 (R = H2N, tBuHN, Me2N) Compounds
Authors: Grüner Bohumír , Štíbr Bohumil , Holub Josef , Císařová Ivana
Published: April 2003

Deprotonation of the eleven‐vertex tricarbaborane zwitterions 7‐L‐nido‐7,8,9‐C3B8H10 [1: L = H3N (1a), tBuH2N (1b), Me2HN (1c)], followed by reactions with metal reagents [FeI2, NiCl2, and Ni(C5H5)2] at higher temperatures and in situ acidification, led to the 7 ⇄ 8 rearrangement of the N‐substituted cage carbon atom to yield a series of 8‐amino‐substituted derivatives of nido‐7,8,9‐C3B8H12. These were characterized as 8‐R‐nido‐7,8,9‐C3B8H11 [2: R = H2N (2a), tBuHN (2b), Me2N (2c)]. A possible rearrangement mechanism for their formation has been proposed. Deprotonation of compound 2a with proton sponge [PS = 1,8‐bis(dimethylaminonaphthalene)] generated the [8‐tBuHN‐nido‐7,8,9‐C3B8H10]− (2b−) anion, which can be reprotonated to give the original compound 2b and not the tautomeric zwitterion 8‐tBuH2N‐nido‐7,8,9‐C3B8H10 (3b). All compounds were characterized by high‐field (11B and 1H) NMR and IR spectroscopy, and mass spectrometry. The molecular structures of the neutral carbaborane 2b and its salt PSH+2b−were determined by single‐crystal X‐ray diffraction analyses. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
New Mononuclear Manganese(III) Complexes with Hexadentate (N4O2) Schiff Base Ligands: Synthesis, Crystal Structures, Electrochemistry, and Electron‐Transfer Reactivity towards Hydroxylamine
Authors: Panja Anangamohan , Shaikh Nizamuddin , Gupta Shankareswar , Butcher Ray J. , Banerjee Pradyot
Published: April 2003

Four new manganese(III) complexes of hexadentate Schiff base ligand obtained from N,N′‐bis(3‐aminopropyl)ethylenediamine and salicylaldehyde, or salicylaldehyde derivatives having N4O2 donor sets − [Mn(sal‐N‐1,5,8,12)]ClO4 (1), [Mn(5‐Cl‐sal‐N‐1,5,8,12)]ClO4 (2), [Mn(5‐Br‐sal‐N‐1,5,8,12)]ClO4 (3), and [Mn(3‐methoxy‐sal‐N‐1,5,8,12)]ClO4·H2O (4) − have been synthesized and characterized. The crystal structures of 1 and 4 have been determined, and the kinetics of the electron‐transfer reactions between these complexes and hydroxylamine hydrochloride have been followed spectrophotometrically in the 5.5−8.0 pH range. Similar kinetic reactivities of all the complexes towards a particular species of the reductant were noted. Hydrogen‐bonded adduct formation between the reactants prior to electron transfer seems to be a possible reaction pathway, according to analysis of the experimental data. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis, Crystallographic and Spectroscopic Studies of Dimeric CuI Complexes with Schiff‐Base‐Containing Triazole Ligands
Authors: Drabent Krzysztof , Ciunik Zbigniew , Chmielewski Piotr J.
Published: April 2003

New CuI complexes of the Schiff‐base‐containing triazole ligands N‐[(E)‐(4‐chlorophenyl)methylidene]‐4H‐1,2,4‐triazol‐4‐amine (ClPhtrz) and N‐[(E)‐phenylmethylidene]‐4H‐1,2,4‐triazol‐4‐amine (Phtrz) have been synthesised and characterised. Depending on the reaction conditions ClPhtrz forms two different dimeric complexes 1 and 2. X‐ray crystallography revealed that each copper centre exhibits a planar trigonal coordination in 1, while the tetrahedral coordination sphere of the copper centre in 2 is completed by a solvent molecule. In dimeric complex 3 the tetrahedral coordination of the CuI ions is formed by two monodentate and two bidentate (bridging) Phtrz ligands. Complexes 1−3 are unstable and easily lose coordinating and/or solvating acetonitrile molecules giving 4 (from 1 and 2) and 5 (from 3). On the basis of ESI MS and 1H NMR and UV/Vis spectroscopy, it was shown that dimeric complexes 1−5 do not survive upon dissolution and dissociate rapidly forming mainly a 1:2 monomeric complex, along with a minor 1:1 complex. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The Electronic Absorption Characteristics of Mixed Phthalocyaninato Porphyrinato Rare Earth(III) Triple‐Deckers M2(TPyP)2(Pc)
Authors: Sun Xuan , Cui Xuegui , Arnold Dennis P. , Choi Michael T. M. , Ng Dennis K. P. , Jiang Jianzhuang
Published: April 2003

Mixed phthalocyaninato tetrakis(4‐pyridyl)porphyrinato rare earth triple‐decker complexes M2(TPyP)2(Pc) [M = La (1), Eu (2)] have been prepared by condensation between M(TPyP)acac generated in situ and M(Pc)2. Their symmetrical structure (TPyP)M(Pc)M(TPyP) was verified by 1H NMR (1D and 2D) spectra in CDCl3 solutions. The electronic absorption spectra of these two compounds were recorded in the UV/Vis and near‐IR region. A weak absorption in the near‐IR region at 860 and 942 nm for 1 and 2, respectively, was observed as the lowest energy band and is attributed to the electronic transition from HOMO to LUMO for these mono(phthalocyaninato) bis(porphyrinato) rare earth complexes. Their electrochemical properties were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Analysis of the relationship between the optical and redox properties of M2(TPyP)2(Pc) reveals that the HOMO and LUMO of M2(TPyP)2(Pc) have both porphyrin and phthalocyanine character. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Structures of Carbonato and Bicarbonato Complexes of Bis(1,10‐phenanthroline)Zinc(II): Experiment and Theory
Authors: Erras‐Hanauer Hans , Mao Zong‐Wan , Liehr Günter , Clark Timothy , van Eldik Rudi
Published: April 2003

We report experimental and theoretical studies on the structure and properties of carbonato and bicarbonato complexes of bis(1,10‐phenanthroline)zinc(II). The complex [Zn(phen)2O2CO] has been synthesized and DFT calculations have been performed based upon its X‐ray structure. The carbonate ligand coordinates in a bidentate binding mode to the metal centre with Zn−O distances of 2.130 and 2.092 Å in the X‐ray structure and 2.027 Å for both distances in the calculated gas‐phase structure. Because of the fundamental role of (bicarbonato)ZnII complexes, especially in different carbonic anhydrases, the structures and properties of the experimentally unknown bicarbonato complexes of this kind were investigated using DFT with different basis sets up to the Ahlrichs triple zeta basis set with additional polarization functions. The bidentate bicarbonato complex [Zn(phen)2O2C(OH)]+ was found to be about 8.2 kcal·mol−1 (SHAsvp), 6.4 kcal·mol−1 (Ahlrichs triple zeta with polarization functions) and 3.5 kcal·mol−1 (Ahlrichs triple zeta) more stable than the quasi‐monodentate bicarbonato complex [Zn(phen)2O(OH)CO]+. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Ethylene Polymerization by Self‐Immobilized Neutral Nickel Catalysts Bearing Allyl Groups
Authors: Zhang Dao , Jin Guo‐Xin , Hu Ning‐Hai
Published: April 2003

[Ni(Ph)(PPh3)(N,O)] complexes containing phenylimino‐phenolato ligands (N,O) (1: N,O = A; 2: N,O = B; 3: N,O = C; 4: N,O = D; 5: N,O = E) have been synthesized and characterized. The molecular structure of 4 was determined by single‐crystal X‐ray analysis. Complexes 2−5 bearing allyl groups have been investigated as self‐immobilized catalysts for ethylene polymerization without the use of co‐catalysts. The high ethylene polymerization activities of ca. 105 g·PE mol−1 Ni·h−1 and high molecular weight (Mw ≈︁ 105) of polyethylene could be accomplished by changing the ligand structures and reaction conditions. The self‐immobilization of catalysts brings about a dramatic increase in the catalytic activities of ethylene polymerization. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Intercalation of Amino Alcohols into α‐Zr(HPO4)2·H2O
Authors: Beneš Ludvík , Melánová Klára , Zima Vítězslav , Patrono Pasquale , Galli Paola
Published: April 2003

The formation of phases during the intercalation of amino alcohols (2‐aminoethanol, 3‐aminopropanol, 4‐aminobutanol, 5‐aminopentanol, and 6‐aminohexanol) into α‐Zr(HPO4)2·H2O was studied. The existence of three phases with general formula α‐Zr(HPO4)2·xNH2(CH2)nOH·zH2O (x = 0.5, 1, 2; n = 2−6; z = 0.2−1.2) depends on the molar ratio of the starting compounds in the reaction mixture. The compounds α‐Zr(HPO4)2·2NH2(CH2)nOH·1.2H2O (n = 5 and 6) lose water and one molecule of amino alcohol upon heating to about 200 °C, as observed by thermal X‐ray diffraction measurements. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Cover Picture: Combining Magnets and Dielectrics: Crystal Chemistry in the BaO−Fe2O3−TiO2 System (Eur. J. Inorg. Chem. 8/2003)
Authors: Siegrist Theo , Vanderah Terrell A.
Published: April 2003

The cover picture shows two views of Ba5Fe4Ti10O31 type structure. Barium atoms are shown as yellow spheres, iron tetrahedra are depicted in red, iron trigonal bipyramids in gold, and titanium octahedra in blue. On the left side is a full unit cell stack of 18 layers, on the right side, the unique 9‐layer repeat unit is shown. Details are discussed in the Microreview by T. Siegrist and T. A. Vanderah on p. 1483 ff.
A Study of the Equilibrium and Kinetics of Urea Binding by a Biomimetic Dinickel(II) Complex
Authors: Kryatov Sergey V. , Rybak‐Akimova Elena V. , Meyer Franc , Pritzkow Hans
Published: April 2003

The equilibrium and kinetics of urea binding by model dinickel complexes have been studied, which is relevant to the activity of the urease enzyme. The pyrazolate‐based, O2H3‐bridged dinuclear nickel(II) complex [LNi2(OH)(H2O)]2+ (1) binds urea reversibly in organic solvents with the formation of an N,O‐bridged urea anion complex [LNi2[OC(NH2)NH)]2+ (2) and two water molecules. The equilibrium constant has been measured as 4.3(4) in acetone, 2.7(5) in acetonitrile, and 3(1) in methanol at 25 °C. Upon dissolving 1 in anhydrous methanol, the O2H3 bridge is substituted for an O2Me2H bridge to give [LNi2(OMe)(MeOH)]2+ (4),which has been crystallized as 4·(ClO4)2 and characterized by X‐ray diffraction. Both NiII ions in 4 are five‐coordinate with geometries intermediate between square‐pyramidal and trigonal‐bipyramidal. The H atom in the Me2O2H bridging unit is located in an asymmetric position. The exchange of water and methanol ligands in complexes 1 and 4 is very fast in solution at 25 °C (kobsd. > 103 s−1). Binding of urea by complexes 1 and 4 are slower reactions (kobsd. ≈︁ 10−1 to 101 s−1 under the concentration conditions used) and can be monitored by stopped‐flow techniques. Detailed kinetic studies indicate that binding of urea is a multi‐step process. Steady‐state intermediates of the tentative formula [LNi2(OR)(urea)n]2+ (n = 1, 2) are formed in fast preequilibrium with the starting complexes 1 (R = H) and 4 (H = Me), respectively. The bidentate N,O‐coordination and deprotonation of an O‐bound urea ligand constitute the overall rate‐limiting step. The kinetic data suggest that both mono‐ and bis(urea) complexes participate in the formation of the chelate 2, and that the latter are substantially more reactive. The bis(urea) pathway was unexpected because only one urea molecule is incorporated into the final product 2. Reactive intermediates [LNi2(OH)(urea)n]2+ are close analogs of the reactive intermediate of urease, which also has the hydroxide and urea ligands bound at a dinickel core. However, the reactivities of the intermediates are different. The hydroxide ligand in our model complex acts as a base towards urea, and the urea anion complex 2 is formed. In urease, the hydroxide ligand attacks urea as a nucleophile leading to the hydrolysis of urea. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)