bluuebunny/crossref_metadata_2025 huggingface dataset:
PHOTON ENERGY DEPENDENCE OF PHASE CONTRAST SYNCHROTRON LIGHT IMAGING
Authors: GROSO A. , MARGARITONDO G. , HWU Y. , TSAI WEN-LI , JE J. H. , LAI B.
Published: October 2002

The changes in phase contrast X-ray images as the photon energy is changed were observed and analyzed. Such results were justified in part with a preliminary model based on the interplay of refraction and absorption effects. The observed change may open up interesting opportunities for chemical analysis based on phase contrast images taken at different absorption edges.
TEMPERATURE EVOLUTION OF THE PHOTOEMISSION SPECTRA FOR THE Si(111) SURFACE USING THE LASER ANNEALING METHOD
Authors: HARUYAMA YUICHI , MATSUI SHINJI , OKUDA TAICHI , HARASAWA AYUMI , KINOSHITA TOYOHIKO , TANAKA SHIN-ICHIRO , MAKINO HIDEO , WADA KATSUO
Published: October 2002

We have studied the electronic structures in a wide temperature range for the Si(111) surface using photoemission spectroscopy combined with the laser annealing method. The temperature dependence of the Si 2p surface-sensitive core level photoemission spectra shows some gradual changes along with the thermal broadening above ~1063 K. In addition, the spectral change in the valence band photoemission spectra was also observed across the 7 × 7–1 × 1 transition temperature. These results indicate that the surface band structure is changed along with structural change at the 7 × 7–1 × 1 transition temperature. With increase of the temperature, the shift of the Si 2p core-level photoemission spectra to the lower binding energy side was observed. We discuss the temperature-induced effects such as the thermal broadening and the observed shift.
NEAR FIELD IMAGING OF THE TRANSIENT COLLISIONAL EXCITATION Ni-LIKE Ag X-RAY LASER
Authors: TANAKA MOMOKO , KAWACHI TETSUYA , KADO MASATAKA , HASEGAWA NOBORU , SUKEGAWA KOUTA , LU PEIXIANG , NAGASHIMA KEISUKE , KATO YOSHIAKI , TAKENAKA HISATAKA
Published: October 2002

The spatial profile of the transient collisional excitation Ni-like Ag X-ray laser in various plasma lengths was observed using the near field imaging method. The gain region was the size of 50 μm and 30–50 μm distant from the target surface. The shapes of the gain region were crescent shape or consisted of two spots.
HIGH RESOLUTION CORE LEVEL SPECTROSCOPY AT THE Cu/Ru(0001) INTERFACE
Authors: ANDERSEN T. H. , BECH L. , ONSGAARD J. , HOFFMANN S. V. , LI Z.
Published: October 2002

Copper adsorption on Ru(0001) has been studied by synchrotron radiation. The clean Ru 3d 5/2 spectra were found to consist of two components with a binding energy shift of 400 meV. The component with the lower binding energy represents the first layer of ruthenium atoms. Adsorption of copper gives rise to core level shifts of the Ru 3d 5/2 components, which were studied as a function of Cu coverage. Experiments were carried out with copper coverages varying from the submonolayer range up to two monolayers of copper. The binding energy of the Cu 2p 3/2 level was measured by X-ray photoemission spectroscopy.
SiL2,3 EMISSION SPECTRA FROM THE INTERFACES IN ANTIFERROMAGNETICALLY COUPLED Fe/Si MULTILAYERS
Authors: IMAZONO TAKASHI , MIYATA NOBORU , KITAKAMI OSAMU , YANAGIHARA MIHIRO
Published: October 2002

An Fe(3.0 nm)/Si(1.3 nm) multilayer had been found to exhibit a fairly strong antiferromagnetic coupling by Endo et al. However, the medium responsible for the interlayer coupling had not been assigned. We measured the Si L2,3 emission spectra from Fe(3.0 nm)/Si (t) multilayers of t = 0.5, 1.0, 1.5, 2.0, and 4.0 nm thick. From the emission spectra the interface of the multilayers was found to consist of dominantly Fe 3 Si alloy. From a rough spectral analysis, there seems to remain a very thin a- Si and/or high-resistive Fe–Si alloy layer sandwiched between the Fe 3 Si layers, which is responsible for the strong interlayer coupling.
SPECIFIC FEATURES OF ULTRASOFT X-RAY BREMSSTRAHLUNG ON SCATTERING OF INTERMEDIATE ENERGY ELECTRONS BY ARGON ATOMS
Authors: GNATCHENKO E. V. , TKACHENKO A. A. , VERKHOVTSEVA E. T.
Published: October 2002

The differential spectra of bremsstrahlung on scattering of intermediate energy (0.3–2 keV) electrons by Ar atoms are studied. The measurements are made in the 6.5–10 nm ultrasoft X-ray region (the photon energy region 190.8–124 eV), where the dynamic polarizability of an Ar atom is low. For each of the wavelengths studied it is found that as the electron energy is increased from 0.3 to 0.7 keV, the bremsstrahlung intensity increases first in direct proportion to the square root of the scattered electron energy and then decreases in inverse proportion to it on subsequent rise in the energy from 0.8 to 2 keV. The increase in the bremsstrahlung intensity with electron energy is explained in terms of the low-energy approximation by the contributions of the opened channels of atom excitation and ionization that accompany the braking effect.
TESTING THE CHARGED ADATOM MODEL ONTO THE ${\rm Sn}_{1-x}{\rm Si}_x/{\rm Si}(111) (\sqrt{3}\times \sqrt{3}){\rm R}30^\circ$ ALLOY WITH HIGH RESOLUTION CORE LEVEL SPECTROSCOPY
Authors: OTTAVIANO L. , PROFETA G. , SANTUCCI S. , PETACCIA L. , PEDIO M.
Published: October 2002

Synchrotron radiation high resolution core level spectroscopy has been used to investigate the 1/3 monolayer (ML) [Formula: see text] solid solution at well-defined values of the mutual surface concentration of the Sn and Si adatoms (x = 0.24 and x = 0.40) as a function of temperature (100–300 K). For 24% Si adatoms at the surface there is low energy electron diffraction (LEED) evidence of a nascent 3 × 3 lowering of the surface symmetry at 100 K. Despite this evidence core level spectroscopy data do not show any signature of the nascent phase transition. Our evidence is in agreement with the analogous observation of no significant spectral changes at reduced temperature of the core level spectra of the isoelectronic and isostructural 1/3 ML Sn/Ge(111) surface.
A SIMPLE XUV SOURCE AT 13.5 NM BASED ON ABLATIVE CAPILLARY DISCHARGE
Authors: ANDREIĆ ŽELJKO , ELLWI SAMIR SHAKIR , PLESLIĆ SANDA , KUNZE HANS-JOACHIM
Published: October 2002

A XUV source that produces a strong emission band at the wavelength of 13.5 nm with a FWHM of 0.6 nm and a duration of about 100 ns is described. In particular this wavelength has attracted the attention of many scientists working in the field by being a good candidate for the development of XUV lithography. The source was generated by using an ablative capillary discharge where the capillary was made of PVC (polyvinyl chloride). A remarkable burst of radiation at the above wavelength was recorded, the intensity of the radiation being higher by a factor of 10 in the spectral region of interest, as compared to usually used capillaries made of POM (polyacetal), or to recently developed capillary discharges in noble gases. Total XUV radiation energy of up to 50 mJ per pulse seems to be possible with such a device. Due to its simplicity, the described capillary discharge is a good candidate for a simple incoherent XUV source at 13.5 nm.
PRECURSOR NONMAGNETIC STATES OF PrFe4P12 AND CePd3 DETECTED BY CORE EXCITATION MCD
Authors: MIYAHARA TSUNEAKI , ISHII HIROYOSHI , OBU KENJI , SHINODA MOTOKI , TAKAYAMA YASUHIRO , MURO TAKAYUKI , MATSUDA TATSUMA D. , SUGAWARA HITOSHI , SATO HIDEYUKI
Published: October 2002

The inverse values of MCD signal intensity on PrFe 4 P 12 and CePd 3 are plotted against temperatures, to be compared with the bulk susceptibility data. It was found that the MCD data are very different from the bulk susceptibility data. The "local" Kondo temperature observed through the present results is much lower than the "coherent" Kondo temperature.
ELECTRONIC STRUCTURES AND REORIENTATION OF PERPENDICULAR MAGNETIC ANISOTROPY OF Co/Au(111) and Co/Pd(111)
Authors: SAWADA M. , HAYASHI K. , KAKIZAKI A.
Published: October 2002

We have investigated electronic and magnetic properties of Co thin films epitaxially grown on Au(111) and Pd(111) substrates by spin- and angle-resolved photoelectron spectroscopy. In the Co/Au(111) system, the magnetization direction of Co changes from perpendicular to parallel to the surface at about 6 ML. The origin of the reorientation is qualitatively explained by the increasing contribution of Co 3d orbitals perpendicular to the surface. In the Co/Pd(111) system, the reorientation of the magnetization direction occurs at about 4 ML, the origin of which is explained as being due to the contribution of the upper Λ3 band of Co with increase of film thickness as in the case of the Co/Au(111) system. The stronger hybridization between Co 3d and Pd 4d states in the Co/Pd(111) system causes larger binding energy shifts of the Λ3 states than in the Co/Au(111) system.
AN EXPERIMENTAL PROOF OF THE BACK-SCATTERING MODEL FOR DICHROIC EFFECTS IN VUV PHOTOEMISSION
Authors: OELSNER A. , SCHICKETANZ M. , FECHER G. H. , SCHÖNHENSE G. , MORAIS J.
Published: October 2002

The energy dependence of the circular dichroism in the angular distribution of photoelectrons (CDAD) was investigated from the shallow Cs 5p core levels. Cesium was prepared in a hexagonal ordered monolayer on W(110). The results are mainly influenced by scattering of the photoelectrons within the adlayer. At low energies, the behavior observed is described by means of a model that treats only the back-scattering of photoelectrons at the potential step between the adlayer and the substrate. It leads to a simple method determining the position of the monolayer with respect to the substrate. In this approach, the back-scattering model is matched with the measured energy dependence of the CDAD between hν = 21 eV and hν = 33 eV . This procedure yields reliable results already for a single observation angle of the photoelectron. The distance between cesium and tungsten was determined to be (2.2 ± 0.1) Å, which corresponds to the effective distance between the center of the adsorbed layer and the potential step between the layer and the substrate. Finally, the fitted result was proven to meet the complete angular dependence of the CDAD at different photon energies.
EPITAXY OF ULTRATHIN CoO FILMS STUDIED BY XPD AND GIXRD
Authors: LUCHES P. , GIOVANARDI C. , MOIA T. , VALERI S. , BRUNO F. , FLOREANO L. , GOTTER R. , VERDINI A. , MORGANTE A. , SANTANIELLO A.
Published: October 2002

CoO layers have been grown by exposing to oxygen the (001) body-centered-tetragonal (bct) surface of a Co ultrathin film epitaxially grown on Fe(001). Different oxide thicknesses in the 2–15 ML range have been investigated by means of synchrotron-radiation-based techniques. X-ray photoelectron spectroscopy has been used to check the formation of the oxide films; X ray photoelectron diffraction has given information concerning the symmetry of their unit cell; grazing incidence X-ray diffraction has allowed to evaluate precisely their in-plane lattice constant. The films show a CoO(001) rocksalt structure, rotated by 45° with respect to the bct Co substrate, with the [100] direction parallel to the substrate [110] direction. Their in-plane lattice constant increases as a function of thickness, to release the in-plane strain due to the 3% mismatch between the bulk CoO phase and the underlying substrate.
RESONANT Lα X-RAY RAMAN SCATTERING SPECTRA OF CeF3, CeO2andCeB6
Authors: NAKAI S. , WATANABE T. , SASAKI K. , IWASAKI T. , ODAKA M. , KASHIWAKURA T. , YAMAZAKI T. , IWAZUMI T.
Published: October 2002

Resonant Lα emission spectra of Ce compounds, CeF 3, CeO 2 and CeB 6, were measured around the LIII absorption threshold. As the energy of the incident photon is tuned at the pre-edge region and at the absorption peaks of the Ce LIII absorption spectrum, the Raman peaks are resonantly enhanced. Obtained spectra are decomposed into Raman and normal Lα emission peaks by line shape analysis. The results show that the Raman spectra provide more detailed information than the absorption spectra about the 4f configuration of Ce compounds.
SOFT X-RAY ABSORPTION SPECTROSCOPY (MnL2,3 AND O K) IN MIXED VALENCE MANGANITES
Authors: SUBÍAS G. , GARCÍA J. , SÁNCHEZ M. C. , BLASCO J. , PROIETTI M. G.
Published: October 2002

Several series of oxides with Mn in a mixed valence state were studied by means of soft X-ray absorption spectroscopy in order to understand better the nature of the electronic structure of these 3d transition metal oxides. XANES spectra of REMnO 3, RE 1-x Ca x MnO 3 (RE: La, Pr and Tb) and RE 0.5 A 0.5 MnO 3 (RE–A: La–Ca, Pr–Ca, Tb–Ca and Pr–Sr) series were recorded at both Mn L 2,3 and O K edges as a function of temperature. The Mn 2p spectra shift towards higher energies with increase of the formal valence of the Mn atom. Moreover, the spectral shape shows minor changes both with the doping ratio (x) and the variation of the RE and/or A cations. No significant changes are also found with temperature across the different magnetic and electrical phase transitions. On the other hand, the O 1s spectra are much more sensitive to the variation of RE (A) cations. The spectra show a prepeak structure at the Fermi energy corresponding to empty states in the O-2p band. This prepeak feature shifts to lower energies and increases its intensity as the formal valence of the Mn atom increases. Finally, neither O K-edge nor Mn L-edge XANES spectra of RE 1-x Ca x MnO 3 compounds can be reproduced by a weighted linear combination of REMnO 3 and CaMnO 3 spectra, indicating that these intermediate composition oxides cannot be described as fluctuating Mn 3+– Mn 4+ mixed valence systems.
ARPES EVIDENCE FOR A QUASIPARTICLE LIQUID IN OVERDOPED Bi2Sr2CaCu2O8+δ
Authors: WELLS B. O. , YUSOF Z. , VALLA T. , FEDOROV A. V. , JOHNSON P. , KENDZIORA C. , JIAN S. , HINKS D.
Published: October 2002

High resolution angle-resolved photoemission spectroscopy of highly overdoped Bi 2 Sr 2 CaCu 2 O 8+δ with Tc = 51 K indicates that the basic transport processes in this material are fundamentally different from both the lesser-doped cuprates and model metallic compounds. The overdoped sample has sharp ARPES peaks at the Fermi energy throughout the Brillouin zone even in the normal state, unlike the lesser-doped compounds. In particular, the spectra near the (π, 0) point show the presence of a sharp peak well above Tc. The ARPES line shapes, and thus the self-energy, at a given energy are almost independent of k. Further, the quasiparticle scattering rate at the Fermi energy seems to be closely tied to direct resistivity measurements. This leads us to the conclusion that overdoped Bi 2 Sr 2 CaCu 2 O 8+δ is best described as a quasiparticle liquid. However, the energy dependence of the scattering rates is quite similar to that found in the lesser-doped compounds and quite different from that seen in a typical metal.
X-RAY EMISSION AND ABSORPTION SPECTRA AND ELECTRONIC STRUCTURE OF MgB2
Authors: KURMAEV E. Z. , LYAKHOVSKAYA I. I. , KORTUS J. , DEMETER M. , NEUMANN M. , IMAZONO T. , MIYATA N. , YANAGIHARA M. , WATANABE M. , MURANAKA T. , AKIMITSU J.
Published: October 2002

Measurements of X-ray emission and absorption of the constituents of MgB 2 are presented. The results obtained are in good agreement with calculated X-ray spectra, with dipole matrix elements taken into account. The comparison of X-ray emission spectra of graphite, AlB 2, and MgB 2 in the binding energy scale supports the idea of charge transfer from σ to π bands, which creates holes at the top of the bonding σ bands and drives the high-Tc superconductivity in MgB 2.
RESONANT INELASTIC SOFT X-RAY SCATTERING OF INSULATING CUPRATES
Authors: DUDA L.-C. , SCHMITT T. , NORDGREN J. , DHALENNE G. , REVCOLEVSCHI A.
Published: October 2002

We have performed high-resolution inelastic X-ray emission scattering experiments at the Cu 3p-, Cu 3s-, and O 1s-resonances of the insulating cuprates CuGeO 3, CuO, La 2 CuO 4, and SrCuO 2. We introduce the novel low-energy s-edge Cu-RIXS which reveals a dd-excitation peak, which was previously unobserved due to insufficient resolution and intensity in high-energy (Cu 1s RIXS). Also, O 1s-RIXS of all cuprate sample is investigated. Surprisingly, there is a large spread in the energy loss values of the RIXS features for different compounds and we explain this by assigning the larger energy features to the occurrence of a Zhang–Rice singlet while the lower energy feature (only observed for CuGeO 3) is assigned to a dd-excitation.
COMPTON SCATTERING CROSS SECTIONS FOR HEAVY ATOMS WITH ACCOUNT OF MANY-ELECTRON CORRELATIONS
Authors: YA. AMUSIA M. , CHERNYSHEVA L. V. , FELFLI Z. , MSEZANE A. Z.
Published: October 2002

Compton ionization of krypton and xenon outer and intermediate subshells is investigated. Results are presented covering the energy transferred to the atoms from their ionization thresholds up to 30 Ry and momentum transferred up to 4 a.u. Calculations are performed in the one-electron Hartree–Fock approximation and with many-electron effects taken into account in the random phase approximation with exchange. It is demonstrated that many-electron correlations play an important role not only in dipole but also in monopole and quadrupole transitions, significantly modifying the cross sections as well as leading to new maxima and minima.
ANALYSIS OF THE ATOMIC Fe3d AND 4s PARTIAL CROSS SECTIONS IN THE REGION OF THE 3p → 3d GIANT RESONANCE
Authors: WHITFIELD S. B. , WEHLITZ R. , KRAUSE M. O. , CALDWELL C. D.
Published: October 2002

Using the technique of photoelectron spectrometry in conjunction with synchrotron radiation, we have carried out a systematic study of the partial cross sections of the main photoelectron lines arising from the ionization of the 3d and 4s subshells of atomic Fe in the vicinity of 3p → 3d autoionizing resonances. Our results confirm the presence of two broad and intense resonances which have been observed earlier. However, our high resolution results also clearly indicate the presence of numerous other weaker resonances. Through a fitting procedure we were able to accurately determine both resonance widths and positions.
COEXISTENCE OF FERROMAGNETISM AND HIGH-TEMPERATURE SUPERCONDUCTIVITY IN Dy-DOPED BiPbSrCaCuO
Authors: BERGER H. , ARIOSA D. , GÁAL R. , SALEH A. , MARGARITONDO G. , LEE S. F. , HUANG S. H. , CHANG H. W. , CHUANG T. M. , LIOU Y. , YAO Y. D. , HWU Y. , JE J. H. , GASPAROV L. V. , TANNER D. B.
Published: October 2002

Ferromagnetism was found to coexist with superconductivity in Dy-doped BiPbSrCaCuO-2212 single crystals up to the superconducting critical temperature Tc ~ 80 K . Several experimental tests indicated that the phenomenon is intrinsic to the entire specimen rather than due to separate phases or to isolated impurities.
RESONANT PHOTOEMISSION STUDY OF RFe4P12 (R = La, Ce, Pr)
Authors: ISHII HIROYOSHI , MIYAHARA TSUNEAKI , TAKAYAMA YASUHIRO , OBU KENJI , SHINODA MOTOKI , LEE CHOL , SHIOZAWA HIDETSUGU , YUASA SEIJI , MATSUDA TATSUMA D. , SUGAWARA HITOSHI , SATO HIDEYUKI
Published: October 2002

We have measured the 4d–4f high-resolution resonant photoemission spectra of RFe 4 P 12 (R = La, Ce, Pr), PrSn 3 and PrAl 2. The Ce and Pr 4f spectra show the spectral features corresponding to a strongly hybridized system. However, the [Formula: see text] and the 3H4 peaks located just below the Fermi energy in the Ce 4f and Pr 4f spectra, respectively, are observed as a shoulder instead of the prominent peak expected for the strongly hybridized or high-Kondo temperature systems.
Na K PHOTOABSORPTION AND RESONANT KLL AUGER SPECTRA IN NaF AND NaCl
Authors: KIKAS A. , NÕMMISTE E. , RUUS R. , SAAR A. , MARTINSON I.
Published: October 2002

The nature of Na 1s photoabsorption in NaF and NaCl is investigated using the resonant Auger decay of Na 1s core excitations. The appearance of new peaks in Auger spectra, when the energy of excitation coincides with the photoabsorption thresholds, shows that the core excitons are created in the threshold region of the Na 1s photoabsorption spectrum. The core excitons around 1074.2 eV originate from the dipole-forbidden 1s -1 3s final state, the population of which is made possible by the symmetry disruption at the photoabsorption site. Another core exciton, excited at photon energies of 1076.8 eV in NaF and 1076.3 eV in NaCl, originates from 1s -1 3p states similar to atoms of Ne and Na. Resonant Auger spectra show also that in NaCl the first sharp photoabsorption maximum at 1076.6 eV has only partially excitonic character.
A PHOTOEMISSION AND INVERSE-PHOTOEMISSION STUDY OF CoSb3
Authors: UEDA Y. , SATO H. , NAGASAKI F. , HIRAI C. , KIMURA A. , TANIGUCHI M. , NAKATAKE M. , NAMATAME H.
Published: October 2002

The valence-band and conduction-band electronic structure of CoSb 3 crystals with a skutterudite type has been investigated by means of ultraviolet photoemission (UPS) with a He discharge lump (hν = 21.2 and 40.8 eV), synchrotron-radiation photoemission (SRPES) and inverse-photoemission spectroscopies (IPES). In the valence bands, the structures at -1.1, -2.5 and -5.8 eV relative to the Fermi level (E F ) are observed in both UPS spectra and SRPES spectra. Taking into account the photoionization cross sections of Co 3d and Sb 5p states and the crystal field splitting of Co 3d states due to the Sb-square ring around Co-ion sites, the main peak at -1.1 eV is attributed mainly to the Co t 2g states, while the Sb 5p states are expected to contribute to the structures at -2.5 and -5.8 eV with a small admixture of Co 3d states. On The other hand, in the conduction bands, a broad feature is observed from E F to ~ 4 eV and a dip is slightly found at around 1 eV. The structures near E F and at around 3.5 eV are considered to be due to the Co e g and hybridization bands between Sb 5p and Co 3d states, respectively.
RESONANT SOFT X-RAY EMISSION SPECTROSCOPY OFV2O3,VO2andNaV2O5
Authors: SCHMITT T. , DUDA L.-C. , AUGUSTSSON A. , GUO J.-H. , NORDGREN J. , DOWNES J. E. , MCGUINNESS C. , SMITH K. E. , DHALENNE G. , REVCOLEVSCHI A. , KLEMM M. , HORN S.
Published: October 2002

Resonant soft X-ray emission (RSXE) spectra of V2O3, VO2and NaV2O5were recorded for a series of excitation energies at resonances of the V L- and O K-absorption band. The V L- and O K-emission in these vanadium oxide bands possess considerable overlap. By resonant excitation we can tune the energy to the absorption thresholds, thereby eliminating this overlap. Hereby we obtain the V 3d and O 2p projected density-of-states of the valence band. Resonant inelastic X-ray scattering (RIXS) is found to be weak in V2O3, which we explain as being due to its metallic character at room temperature. Vanadium dioxide ( VO2), semiconducting at room temperature, shows considerable RIXS features only at the O K-emission band. Distinct RIXS structures are visible in the RSXE spectra of the insulator NaV2O5. In the emission spectra excited at the V L-thresholds of this ternary vanadium oxide, dd-excitations of the V dxysubband at an energy loss of -1.7 eV are observed. Our observation, that RIXS is stronger for insulators than for metals, should be taken advantage of for studying insulator-to-metal transitions in vanadium compounds in the future.
Do WE UNDERSTAND THE STRUCTURE OF THE GALLIUM-RICH SURFACE of GaAs(001)? EXPERIMENTAL AND THEORETICAL APPROACHES
Authors: PAGET D. , PULCI OLIVIA , SAUVAGE M. , GARREAU Y. , REINING LUCIA , CHIARADIA P. , BECHSTEDT F. , PINCHAUX R.
Published: October 2002

While the As-rich 2 × 4 reconstruction of GaAs(001) is well explained by the so-called β2 structure, the atomic structure of the Ga-rich 4 × 2 phase has been discussed for a long time. In this review, the most important structural models for the GaAs(001) (4 × 2)/c(8 × 2) surface are compared from different theoretical and experimental points of view. The selected reconstructions include the recently proposed ζ model, a new mixed dimer model, and the well-known β, β2, Cerdà and Skala models. The different structures are compared on the basis of total energy calculations, simulations of STM experimental images and interpretation of X-ray diffraction data. Only the ζ model satisfies all criteria, and provides therefore a satisfactory explanation of the atomic structure of GaAs(001)-(4 × 2).
GROWTH AND MELTING OF THE CLEAVAGE FACE $\{10 \bar{1}1\}$ of Yb:YAl3(BO3)4 Crystal
Authors: ZHAO SHANRONG , WANG JIYANG , SUN DALIANG , LI JING , LIU HONG
Published: October 2002

Yb:YAl3(BO3)4 (YbYAB) is a self-frequency-doubling laser crystal. In this paper, we report a series of atomic force microscopy (AFM) observations on the growth and melting of the cleavage face [Formula: see text] of the crystal. Both growth and nucleation rates are very fast when the flux temperature is 0.5–1.5°C below the saturation point. These fast growth and nucleation rates are related to the nonsaturated bonds on the cleavage face formed during cleaving. The growth morphologies sensitively change to spiral melting holes when the flux temperature increases by only 0.5°C above the saturation point. When the temperature increases by another 1°C, the spiral melting mechanism transforms into a two-dimensional nucleation melting mechanism. The heights of the growth or melting steps are n × unit height of the structure layer in this direction. The melting step height increases much as the temperature increases by 1°C, but the growth step height increases only a little as the temperature decreases by 1°C. The melting steps are much wider than the growth steps, which reflects the fact that the melting centers (or melting nuclei), unlike the growth nuclei, are difficult to form. The growth morphology is not reverse-symmetric to the melting morphology as the temperature variation is reverse-symmetric on the saturation point.
VIBRATIONAL PROPERTIES OF TWO ISOLATED STEPS: A THEORETICAL MODEL
Authors: RAFIL O. , LALAOUI A. , TAMINE M. , KHELIFI A.
Published: October 2002

We investigate the dynamical properties of two isolated steps on the surface. We present the solution of the full dynamical problem arising from the absence of translation symmetry in two dimensions due to extended surface steps on the surface boundary of an insulating substrate. The calculations concern in particular the dynamics of localized modes of an atomic step on the surface of a cubic lattice. The theoretical approach determines the vibrational field in both steps. The matching method, which constitutes a powerful formalism for determining the vibrational properties of such disordered surfaces, is used. The model presented in this study consists of two monatomic steps as the interface between three coupled semi-infinite and single semi-infinite atomic layers. The dynamical properties of the perfect waveguides are presented and calculated numerically. The breakdown of translational symmetry perpendicular to the step edges gives rise to several Raleigh-like branches localized in the neighborhood of the steps. Typical dispersion curves for these modes along the steps are given with their polarization.
GRAIN BOUNDARY SEGREGATION OF HYDROGEN IN BCC IRON: ELECTRONIC STRUCTURE
Authors: GESARI S. B. , PRONSATO M. E. , JUAN A.
Published: October 2002

The electronic properties of H impurity in an Fe Σ = 5, 53.1° [100] (012) symmetrical tilt grain boundary (GB) were studied using qualitative electronic structure calculations in the framework of the atom superposition and electron delocalization molecular orbital (ASED-MO) theory. A large cluster containing 197 Fe atoms was used to simulate the local environment of the boundary. The most stable positions for one H atom and two H atoms at the GB core were determined. The total energy of the cluster decreases when the H atoms are at that location, making it a possible site for H accumulation. The binding energy found was less than that of a Σ = 5 [100] (013) GB. An analysis of the orbital interaction reveals that H–Fe bonding involves mainly the Fe 4s and H 1s orbitals. A higher contribution of d orbitals is present, which show a different behavior when compared with mixed dislocation and vacancy in the bulk Fe. The interatomic bonding along the Fe atom chains via H atoms is very inefficient, thus resulting in significant weakening of the interatomic bonding. H–H interaction was also analyzed.
New Holland Tractors (India)
Authors: Rath Devashis
Published: October 2002

With the opening up of the Indian economy many multinational companies are making a foray into Indian markets. Diverse strategies are being adopted to compete and establish themselves among Indian consumers. One such multinational who has entered India is CNH, the world's largest agricultural equipment manufacturer. The fully owned subsidiary, New Holland Tractors (India) Pvt. Ltd., NHI in short, has targeted the vast Indian tractor market. This case is about how NHI has experimented with the concept of a team and process based organization in India. The case details the processes involved in setting up a team and process based organizational design as well as the current challenges.
FAILURE OF COMPRESSION HIP SCREW: ANALYSIS OF THE FAILURE MECHANISM
Authors: Chang Chi-Wei , Lai Kuo-An , Yang Chyun-Yu
Published: October 2002

Compression hip screw is a well-accepted fixation device for peritrocahnteric fractures in old people. However, mechanical failures of the device were frequently reported, most of them condemned osteoporosis as the major cause of failure. Few reports discussed the pitfalls of the design of the device. We retrospectively reviewed 205 cases of peritrochanteric fracture treated in our institute with compression hip screw from 1998 to 2001. Fifteen patients (7.3%) had mechanical failure, where 14 of them (93.3%) were cutting out of the lag screw. Statistical analysis found that mechanical failures of the compression hip screw were more often in women than men (p < 0.05) and more often in unstable fractures (Boyd and Griffin types III and IV) than stable fractures (types I and II). The length of the lag screw (average 80.6 mm, range 75–95 mm) in the failure group was significantly shorter than that of the non-failure group (average 85.4 mm, range 75–100 mm) (p < 0.05). The Aesculap Compression hip screw used in our institute has a barrel length of 38 mm and a threaded part of the lag screw 24 mm in length. The average sliding capacity for the failure group was only 18.6 and was not enough for the fracture settling. Fourteen patients had the lag screw cut out of the femoral head at the end of sliding of the fixation device. We suggest application of a device with a shorter barrel and threaded part for patients with short femoral necks to gain more sliding distance in order to reduce the failure rate.
EXCESS CAPACITY IN POST ENTRY COURNOT COMPETITION
Authors: THÉPOT JACQUES
Published: October 2002

This paper discusses the occurrence of excess capacity in a post entry duopoly continuous time model when capacity building is irreversible. It is proved that the Cournot–Nash strategies used by firms may induce persistent capacity for the established firm. In the linear demand case, the investment periods of the established firm and the entrant are analytically derived. These results generalize findings of Spulber (1981). A comparative test in terms of rational expectations of quantities is designed to characterize excess capacity occurrence.
A GAME MODEL OF IRREVERSIBLE INVESTMENT UNDER UNCERTAINTY
Authors: MURTO PAULI , KEPPO JUSSI
Published: October 2002

Most of the literature on real options considers the optimal decision of a firm in isolation from competitors. In reality, however, the actions of competing firms often affect each other's investment opportunities. We develop a game model where many firms compete for a single investment opportunity. When one of the firms triggers the investment the opportunity is completely lost for the other firms. The value of the project for the firms is assumed to follow a geometric Brownian motion. The model combines game theory and the theory of irreversible investment under uncertainty. We characterize the resulting Nash equilibrium under different assumptions on the information that the firms have about each other's valuations for the project. As an example, we present a case of building a telecommunications network.
THEORETICAL AND EXPERIMENTAL RECOVERY OF OSCILLATIONS DURING BATCH YEAST GROWTH IN A PURE CULTURE SUBJECT TO NUTRITIONAL STRESS
Authors: VADASZ A. S. , VADASZ P. , GUPTHAR A. S. , ABASHAR M. E.
Published: October 2002

A new model is proposed for the recovery of the complete cell growth dynamics, and showed to compare well with new experiments that we conducted for a pure culture of the T206 strain of Saccharomyces cerevisiae. The proposed model results show that the batch yeast growth in a limited nutrient medium (5% grape juice) is associated with substantial oscillations, which damp out over time. Additional results obtained by using the proposed model show the recovery of effects that are frequently encountered in experiments such as a "Lag Phase" as well as an inflection point in the "ln curve" of the cell concentration. The proposed model recovers also the logistic growth curve as a special case.
IT ENABLING: ESSENCE OF VIRTUAL ORGANIZATIONS
Authors: TIANFIELD HUAGLORY , UNLAND RAINER
Published: October 2002

Firstly, insight on the essence of virtual organizations is presented, which is IT enabling. Then, a brief overview is given upon the papers that are included in the special issue.
ADAPTIVE TRADERS FOR COMMUNICATION IN COOPERATIVE ROOMS
Authors: KLOOS REINHOLD , REINEMA ROLF , SCHROEDER MICHAEL
Published: October 2002

In distributed systems, traders mediate between clients and service providers. This paper introduces a trading model, which supports multiagent systems (MAS) and goes beyond simple trading in three ways: (a) Service composition — The trader composes complex services of the current service offers. During the composition, it checks the availability of the service offers. (b) Use of group agents — Group agents represent a group of agents with their individual policies and other context information. The trader can use the group agent's information for a pre-selection of service offers. (c) Adaptability — The trading model uses the notion of clients' trust into services and adapts to the clients' preferences and system policies. The trading model is used in a Computer-Supported Cooperative Work (CSCW) application, in which the trader finds adequate communication services for project teams with geographically distributed members.
A STUDY ON TELE-COLLABORATIVE PRODUCT DEVELOPMENT
Authors: YAN JUNQI , SHEN JUNYING , SHEN WEIMING
Published: October 2002

The tele-collaborative product development (TeleCo-PD) is an important technology for modern enterprises to win in the 21st century global market. It concerns how to utilize distributed product development resources to design and manufacture a new product. This paper presents a series of tools developed to construct a TeleCo-PD platform, which provides small and middle size enterprises with the ability to collaborate with each other. The proposed platform is based on an Integrated Service Digital Network (ISDN), with a Client/Server based process management system for defining and assigning tasks, a whiteboard for sharing engineering drawings, and a File Transfer Protocol server for transferring product data files. The platform has been deployed in a virtual enterprise in developing a new digital camera.
DEVELOPMENT OF AGENT-BASED E-COMMERCE SYSTEMS USING SEMIOTIC APPROACH AND DEMO TRANSACTION CONCEPT
Authors: BARJIS JOSEPH , CHONG SAMUEL , DIETZ JAN L. G. , LIU KECHENG
Published: October 2002

As software agents get more sophisticated, it becomes difficult to understand and model such systems. This paper contends that all developers bring to the task of development some implicit or explicit assumptions of the agent communication pattern. This issue is not readily addressed in current literature and represents a gap in knowledge. For this purpose, a generic pattern of inter-agent communication is introduced and discussed in this paper. For better understanding and modelling of agent-based e-commerce systems, the semiotic approach and the DEMO transaction concept are briefly introduced. It is shown that the semiotic approach offers a unifying framework for identifying the roles of agents, the responsible human agents and the right/constraints associated with each role. The DEMO transaction concept is applied to model the communicative interaction between agents.
SURPLUS VALUES IN INFORMATION ECOSYSTEMS
Authors: CARLSSON BENGT , DAVIDSSON PAUL
Published: October 2002

A model of surplus values within information ecosystems is presented. The model is based on the classical definition of surplus value. However, as this definition was developed within a manufacturing industry context, some modifications are necessary to adopt it to the context of information ecosystems, e.g. by taking into account that products are "virtual" rather than physical. Just as in agent-based computational economics, here the economics is modelled as evolving systems of autonomous interacting agents in an evolutionary framework. In this way the resulting model is able to capture more dynamic scenarios. The model is formally specified in terms of price, profit, and group gaining functions and is applied to some examples of societies of selfish agents in antagonistic groups to illustrate its dynamic properties. Moreover, the paper show how the model builds upon labour theory of value and contrasts it to consumer value models.
PATHWAY ANALYSIS ON ELECTRON TRANSFER IN RUTHENIUM MODIFIED CYTOCHROME c
Authors: CHEN GUANHUA , TSANG CHUN KIT , TONG GLENNA S. M.
Published: October 2002

An efficient Green's function based search procedure is developed and applied to identify important charge transfer pathways in a cytochrome c and its derivatives. Compared to the existing methods, this procedure is much more efficient, and is complete in its search. Important residues are determined. However, no single charge transfer pathway is identified.
COMPUTATIONAL METHOD FOR DRUG TARGET SEARCH AND APPLICATION IN DRUG DISCOVERY
Authors: CHEN Y. Z. , LI Z. R. , UNG C. Y.
Published: October 2002

Ligand-protein inverse docking has recently been introduced as a computer method for identification of potential protein targets of a drug. A protein structure database is searched to find proteins to which a drug can bind or weakly bind. Examples of potential applications of this method in facilitating drug discovery include: (1) identification of unknown and secondary therapeutic targets of a drug, (2) prediction of potential toxicity and side effect of an investigative drug, and (3) probing molecular mechanism of bioactive herbal compounds such as those extracted from plants used in traditional medicines. This method and recent results on its applications in solving various drug discovery problems are reviewed.
DYNAMICS OF O + O3 REACTION ON A NEW POTENTIAL ENERGY SURFACE FOR GROUND-TRIPLET TETRAOXYGEN: SPECTATOR BOND MECHANISM REVISITED
Authors: VARANDAS A. J. C. , LLANIO-TRUJILLO J. L.
Published: October 2002

We report a dynamics study of the reaction [Formula: see text] using an improved double many-body expansion (DMBE II) potential energy surface for the ground triplet state of O 4. Values of the calculated cross section, vibrational and rotational distributions, as well as thermal rate coefficient as a function of temperature are given. While some discrepancy with experiment is found in the rotational distribution of the product O 2 molecules with vibrational quantum number v = 12, the agreement is quite good for the thermal rate coefficient over the whole range of temperatures where theory and experiment overlap. No breakdown of a previously suggested spectator bond mechanism is observed. Reasons to support such an evidence are given from ab initio calculations by looking at the variation of the energy and calculated bond distances as a function of the intrinsic reaction coordinate along the products channel.
Electrooptical Device Based on Polymer-Dispersed Liquid Crystal Films
Authors: Fuh Andy Ying-Guey , Huang Chi-Yen , Tzen Bao-Wen , Sheu Chi-Ren , Chyr Yeong-Ning , Gen-Lan Lin Gen-Lan Lin , Tsung-Chih Ko Tsung-Chih Ko
Published: October 2002

An electrooptical device based on polymer-dispersed liquid crystal films was fabricated. It is a filter which, under application of a suitable voltage, can convert a Gaussian beam into a beam with a more uniform intensity profile. The fabrication of this device and its electrooptical characteristics are reported.
Crystallization Behavior of Cordierite-Based Glass with Excess SiO2 and Al2O3 at Initial Stage
Authors: Son Yong-Bai , Kim Chong-Hee , Jang Sung-Do , Liu Jun , Mehmet Sarikaya Mehmet Sarikaya , Ilhan A. Aksay Ilhan A. Aksay
Published: October 2002

Crystallization behavior of cordierite-based glass with excess SiO2 and Al2O3 (CM glass) was studied at the initial crystallization stage. Two kinds of glass-in-glass phase separation occurred during the heat treatment of glass powder. The secondary glass-in-glass phase separation, which consists of an SiO2-rich phase and an Al2O3-rich phase significantly affects the crystallization of the glass and the resultant microstructures of the crystallized glass. Mullite nucleated first in the Al2O3-rich amorphous phase which is no longer a stable glass-forming region. Metastable µ-cordierite crystallized in the SiO2-rich amorphous phase and grew rapidly. A fine-grained cordierite-mullite composite with mullite as the grain boundary phase was produced.
Characterization of Quartz Pressure Gauges by Using the Cluster Sampling Technique
Authors: Makoto Kimura Makoto Kimura , Katsuhiko Nishida Katsuhiko Nishida
Published: October 2002

The Cluster Sampling Technique (CST) developed to analyze the noise terms of atomic clocks and gyroscope has been applied to characterization of high-precision pressure quartz gauges. The log-log plot of the cluster variance defined as the variance of adjoining cluster vs cluster time is used to analyze the noise terms of time series measurement data. One of the test samples is a newly developed quartz pressure gauge having a dual mode SC-cut resonator. Two other commercial gauges are a BT-cut quartz probe and an AT-cut quartz gauge. The CST analysis results show that the dual mode SC-cut gauge has the lowest values for all noise factors analyzed.
High-Resolution Transmission Electron Microscopy of Si/Ge Interfacial Structures
Authors: Ikarashi Nobuyuki , Toru Tatsumi Toru Tatsumi , Koichi Ishida Koichi Ishida
Published: October 2002

A <110> cross-sectional high-resolution transmission electron microscopy (HREM) method for atomic scale observation of Si/Ge interfacial structures has been developed. The HREM image intensities of Si and Ge are theoretically investigated under various imaging conditions. The results show that their images exhibit strong contrast for an EM specimen thickness near the Ge extinction distance (14.8 nm) under a focus-setting of -10 nm. This is due to the large difference in the {111} amplitudes between Ge and Si. An EM specimen preparation technique in which chemical etching was used to remove ion milling artifacts was employed to accomplish this observation. Using this HREM method, observations of the Si/Ge interfacial structure are achieved, giving information about interfacial ordering.
GaAs/AlGaAs Light Emitters Fabricated on Undercut GaAs on Si
Authors: Wada Naoki , Sakai Shiro , Yoshimi Shinichi , Yoshihiro Shintani Yoshihiro Shintani , Masuo Fukui Masuo Fukui
Published: October 2002

Stable GaAs/AlGaAs light-emitting diodes (LEDs) on Si substrates were realized by growing device structures on undercut GaAs on Si (UCGAS) which reduces both thermal stress and dislocation density. The output efficiency of the UCGAS LEDs was almost the same as that of homoepitaxial LEDs, and maintained stable operation for 3000 h. The device degradation mechanism in conjunction with the residual stress and the dislocation density was investigated, and it was found that the stress had a more significant effect on device degradation than the dislocation density. The output efficiency and the thermal properties of the LEDs are also analyzed. UCGAS lasers were fabricated, and both efficiency and threshold current equal to those of homoepitaxial lasers were obtained.
Magnetoresistance and Interlayer Exchange Coupling between Magnetic Layers in Fe–Mn/Ni–Fe–Co/Cu/Ni–Fe–Co Multilayers
Authors: Hoshino Katsumi , Noguchi Shin , Nakatani Ryoichi , Hiroyuki Hoshiya Hiroyuki Hoshiya , Yutaka Sugita Yutaka Sugita
Published: October 2002

Magnetoresistance effects and interlayer exchange coupling between magnetic layers have been investigated in [Hf/Fe–Mn/Ni–Fe–Co/Cu/Ni–Fe–Co/Hf] multilayers by varying the thicknesses of the Ni–Fe–Co, Fe–Mn, and Cu layers. When the Fe–Mn layer is thicker than 5.0 nm, it applies a strong exchange-bias field to the neighboring Ni–Fe–Co layer. The multilayers show high magnetoresistance ratios at Cu-layer thicknesses between 2.0 and 3.0 nm, because the interlayer exchange coupling is weak. The interlayer exchange coupling between the two Ni–Fe–Co layers is always ferromagnetic at Cu-layer thicknesses between 0.5 and 5.0 nm.
A Consideration on Galvanomagnetic Phenomena in Ni–Fe Thin Films
Authors: Keiichi Kakuno Keiichi Kakuno
Published: October 2002

The dependence of the galvanomagnetic electromotive force (GEMF) effect on the Ni concentration of Ni–Fe alloys has been studied experimentally as compared with the Hall and the magnetoresistance (MR) effects. The essence of the GEMF effect and the MR effect has been found to be the phenomenon that an electric field is generated perpendicularly to an equivalent magnetic induction vector. The GEMF effect has a not less advantage than the MR effect, in that the GEMF effect is composed of only the pure galvanomagnetic phenomenon contrary to the MR. A formula with which the present galvanomagnetic phenomena can be well understood has been obtained on the basis of the modefied two carrier types model.
Theoretical and Experimental Studies on Depth-Induced Light Extinction in Nematic Droplets
Authors: Ding Jiandong , Junxiang Zhu Junxiang Zhu , Yuliang Yang Yuliang Yang
Published: October 2002

The effect of depth-induced light extinction (DILE) is proposed and investigated both in theory and in experiment. This phenomenon may occur by adjusting the effective depth of an anisotropic entity observed orthoscopically in a polarizing microscope while maintaining the internal structure. The analytical interpretations are made in both monochromatic light and multichromatic light and reveal that the DILE effect is much more obvious in monochromatic light. The DILE in the radial nematic droplet as well as that in the normal-oriented axial one is then calculated and analysed in detail. The experimental observations are in satisfactory agreement with corresponding theoretical analyses and prove that the nematic droplets in the poly(methyl acrylate)-based polymer dispersed liquid crystal (PDLC) film have the radial director configuration. The advantage of DILE is that it can, by two-dimensional polarizing micrographs, reflect the third dimension parallel to the incident light. Some prospective applications of DILE are pointed out. Finally, extinction effects besides DILE are classified and discussed.
Asymmetry in Indentation-Induced Mechanical Damage on Si (111) Surfaces
Authors: Takashi Iizuka Takashi Iizuka , Yasumasa Okada Yasumasa Okada
Published: October 2002

Asymmetry in indentation-induced mechanical damage on Si (111) surfaces is investigated by using optical microscopy and X-ray diffraction topography. Cracks, residual strain fields and anneal-induced dislocation rosettes around the indentation are found to represent the asymmetries in the [1̄1̄2] and reverse [112̄] directions on the (111) surface. The crack formation along three <112> directions and the residual strain field distribution along <112> directions are discussed in terms of dislocation reaction and silicon crystal structure, respectively.