bluuebunny/crossref_metadata_2025 huggingface dataset:
Condensation of silicon nanowires from silicon monoxide by thermal evaporation — An X-ray absorption spectroscopy investigation
Authors: Kim P -SG , Tang Y -H , Sham T K , Lee S T
Published: December 2007

We report a Si K-edge X-ray absorption fine structures (XAFS) study of silicon monoxide (SiO), the starting material for silicon nanowire preparation, its silicon nanowires, and the residue after the preparation of the starting material. The silicon nanowires were condensed onto three different substrates, (i) the wall of the furnace quartz tube, (ii) a porous silicon substrate, and (iii) a Si(100) silicon wafer. It was found that the Si K-edge XAFS of SiO exhibits identifiable spectral features characteristic of Si in 0 and 4 oxidation states as well as in intermediate oxidation states, while the SiO residue primarily shows features of Si(0) and Si(4). The XAFS suggest that SiO is not exactly a simple mixture of Si and SiO2. The silicon nanowires produced by the process exhibit morphology and luminescence property variations that depend on the nature of the substrate. X-ray excited optical luminescence (XEOL) at the O K-edge suggests an efficient energy transfer to the optical decay channel. The results and their implications are discussed.Key words: silicon nanowires, thermal evaporation, silicon monoxide, X-ray absorption fine structures, X-ray excited optical luminescence.
Dipole oscillator strength distributions, properties, and dispersion energies for ethylene, propene, and 1-butene
Authors: Kumar A , Jhanwar B L , Meath W
Published: December 2007

A recommended isotropic dipole oscillator strength distribution (DOSD) has been constructed for the ethylene molecule through the use of quantum mechanical constraint techniques and experimental dipole oscillator strength (DOS) data; the DOS data employed are recent experimental results not available at the time of the original constrained DOSD analysis of this molecule. The constraints are furnished by molar refractivity data and the Thomas–Reiche–Kuhn sum rule. The DOSD is used to evaluate a variety of isotropic dipole oscillator strength sums, logarithmic dipole oscillator strength sums, and mean excitation energies for ethylene. Pseudo-DOSDs for this molecule, and for propene and 1–butene, which are based on an earlier constrained DOSD analysis for these molecules, are developed. They are used to obtain reliable results for the isotropic dipole–dipole dispersion-energy coefficients C6, for the interactions of the alkenes with each other and with 47 other species, and the triple-dipole dispersion-energy coefficients C9 for interactions involving any triple of molecules taken from ethylene, propene, and 1–butene.Key words: alkenes, dipole properties, pseudo-states, dipole–dipole and triple-dipole dispersion energies, long-range additive, non-additive interaction energies.
Pulsed-field ionization electron spectroscopy and molecular structures of copper-(pyridine)n (n = 1, 2) complexes
Authors: Wang Xu , Sohnlein Bradford R , Li Shenggang , Fuller Jason F , Yang Dong-Sheng
Published: December 2007

Cu-(pyridine)n (n = 1, 2) complexes are prepared in a pulsed laser ablation cluster source and identified using laser photoionization time-of-flight mass spectrometry. High-resolution electron spectra of these complexes are obtained using pulsed-field ionization zero electron kinetic energy (ZEKE) photoelectron spectroscopy. Metal-pyridine and pyridine-based vibrational modes are identified by comparing the ZEKE spectra with previous spectroscopic studies of isolated pyridine, pyridine adsorbed on metal surfaces, and other Cu complexes. Ground electronic states and molecular structures are determined by comparing the ZEKE spectra with ab initio and multidimensional Franck-Condon factor calculations. Metal-pyridine bond energies of the neutral complexes are derived from the measured ionization energies and thermochemical relations. The mono-ligand complex has C2v symmetry in both the neutral and ionized forms, whereas the di-ligand complex has an eclipsed pyridine configuration with D2h and C2 symmetries for the ion and neutral species, respectively. Although both the mono- and di-pyridine Cu complexes are formed by Cu binding to nitrogen atoms, important binding differences are found between these two complexes.Key words: pulsed-field ionization, ZEKE, photoelectron, ab initio, copper-pyridine complexes.[Traduit par la Rédaction]
High-resolution XANES S L3,2 edge spectra collected from a series of iron-bearing sphalerite(Zn,Fe)S minerals
Authors: Pratt Allen , Zuin Lucia , Yiu Y Mui , Harmer Sarah
Published: December 2007

High-resolution S L3,2-edge XANES spectra have been collected from a series of high-quality sphalerite samples. Each of the sphalerite samples examined has a characteristic iron concentration, and the range is from <0.01 to 14.79 wt% Fe. The structures of the S L3,2-edges are investigated by comparing ab initio calculated spectra with experimentally measured S L3,2-edge spectra collected from synthetic ZnS sphalerite. The theoretical and experimental data provide evidence that S 2p electron transitions to empty S 3s and S 3d states can occur across an energy range above the absorption edge. A chemical shift, associated with iron to sulphur bonds, is identified, and for the first time, a pre-edge feature associated with S–Fe bonding in sphalerite is observed.Key words: XANES, zincblende, sphalerite, characteristic iron content, S L-edge structure, ab initio calculated spectra, density of states, pre-edge peak.
Chemical forms of calcium in Ca,Zn- and Ca,Cd-containing grains excreted by tobacco trichomes
Authors: Sarret Géraldine , Isaure Marie-Pierre , Marcus Matthew A , Harada Emiko , Choi Yong-Eui , Pairis Sébastien , Fakra Sirine , Manceau Alain
Published: December 2007

Tobacco (Nicotiana tabacum L. cv. Xanthi) plants exposed to toxic levels of zinc and cadmium excrete metals through their leaf trichomes (epidermal hairs) as Zn,Ca- and Cd,Ca-containing grains. Little is known about the nature and formation mechanism of these precipitates. The chemical, crystalline, and noncrystalline compositions of individual grains produced by tobacco were studied by scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX), micro-X-ray diffraction (µXRD), and calcium K-edge micro X-ray absorption near edge structure (µXANES) spectroscopy. Zinc is predominantly incorporated in calcite and cadmium in calcite and vaterite. Aragonite, which occurs occasionally, does not seem to contain trace metals. In addition to being precipitated in its three possible polymorphic forms, calcite, aragonite, and vaterite, calcium is also speciated as amorphous CaCO3 and possibly organic Ca in some grains. Most often, a particular grain consists of two or more crystalline and noncrystalline phases. The observed variability of intra- and inter-grain elemental and phase composition suggests that this biomineralization process is not constrained by biological factors but instead results from thermodynamically and kinetically controlled reactions. This study illustrates the potential of laterally resolved X-ray synchrotron radiation techniques (µXRD and µXANES) to study biomineralization and metal immobilization processes in plants.Key words: biomineralization, detoxification, micro-XANES, micro-XRD.
Examination of the proposition that Cu(II) can be required for charge neutrality in a sulfide lattice — Cu in tetrahedrites and sphalerite
Authors: Buckley Alan N , Skinner William M , Harmer Sarah L , Pring Allan , Lamb Robert N , Fan Liang-Jen , Yang Yaw-wen
Published: December 2007

Synchrotron XPS and Cu L2,3-edge NEXAFS spectroscopic data for a natural tetrahedrite surface prepared by fracture under UHV were in accord with the composition of the mineral and its expected semiconductivity. The 2p binding energy for the 6-coordinate S atoms was found to be not detectably greater than that for the 4-coordinate S atoms, and surface species were not clearly discernible in either surface-optimized S 2p or Cu 2p spectra. The Cu 2p and Cu L2,3-edge spectra indicated that all Cu in the mineral was indisputably Cu(I). The Cu L2,3-edge spectra of relatively pure natural sphalerite treated with mildly acidic aqueous cupric solution revealed the presence of Cu(II) in the outermost layer of the fracture surfaces, but it was concluded that most of the Cu near the surface of the mineral was in formal oxidation state Cu(I), albeit with higher than normal d9character. The Cu(I) absorption peak was at an energy much lower than for the tetrahedrite absorption edge, but still consistent with Cu(I) in 4-fold coordination by S. The Cu(II) was consistent with Cu bonded both to S atoms in the outermost layer of the sphalerite and to O atoms in chemisorbed water. S 2p spectra determined at different photon energies revealed high binding energy components arising from oligosulfide-like environments in the outermost layers, but not necessarily in a completely restructured lattice and not in a Cu oligosulfide only. The data indicated some loss of Zn in addition to the Zn that had been replaced by Cu in the outermost layers of the sulfide lattice. The presence of these oligosulfide-like environments precluded the detection of S with formal oxidation state greater than (-II) that might have arisen only from Cu(I) in the S lattice. No evidence was obtained for the presence of Cu(II) in a sulfide lattice, but it was not possible to exclude the possibility of a very low concentration because of the presence of the Cu(II) bonded to both S and O at the surface of the treated sphalerite.Key words: tetrahedrite, sphalerite, copper uptake, XPS, NEXAFS.
Formation of group 12 [Zn, Cd] mixed-chalcogen nanoparticles from the reagent Me3Si-SeS-SiMe3
Authors: Turner Elizabeth A , Rösner Harald , Huang Yining , Corrigan John F
Published: December 2007

Mixed-chalcogen metal chalcogenide nanoparticles (MSexS1-x; M = Zn, Cd) have been synthesized using Me3Si-SeS-SiMe3 as a delivery source of Se2– and S2– to the metal core. This method demonstrates the ease with which mixed-chalcogen particles can be fabricated at low temperature using colloidal techniques. Reaction with Me3Si-SeS-SiMe3 occurs via a redox pathway resulting in Se–S bond cleavage and ultimately contributing to the nonequivalent Se:S ratio observed in the isolated particles. Subsequent thermolysis of ZnSe0.57S0.43 and CdSe0.28S0.72 in hexadecylamine gives rise to controlled particle growth while maintaining the observed stoichiometry. Particles are characterized by EDX, TEM, and powder X-ray diffraction analysis in conjunction with UV–vis absorption and photoluminescence (PL) spectroscopy.Key words: nanoparticles, semiconductors, mixed-chalcogen, quantum confinement, Group 12.
The contribution of XANES spectroscopy to tribology
Authors: Nicholls M , Najman M N , Zhang Z , Kasrai M , Norton P R , Gilbert P U P A
Published: December 2007

X-ray absorption near edge structure spectroscopy (XANES) analysis has been routinely used to study the complex chemical interactions between additives in engine oil and metallic surfaces during high-temperature and pressure reciprocating wear conditions. XANES analysis provides detailed chemical and structural information on the resultant antiwear and tribo films formed on metallic surfaces. The following review will illustrate how XANES analysis on the macro scale can provide the information required to elucidate complex film formation mechanisms, then describes the use of emerging XANES spectromicroscopy to such systems, and concludes by showing the complementary nature of the macro and micro scale spatially resolved XANES analysis; Professor Bancroft has utilized the combination of these to stay at the forefront of XANES research in the field of tribology and in spectroscopy science in general.Key words: tribology, XANES, X-ray absorption near edge structure spectroscopy, metals, thiophosphates, spectromicroscopy, tribochemistry.
Pushing the limit of confocal polarized Raman microscopy
Authors: Lagugné-Labarthet François
Published: December 2007

Raman microscopy has emerged as a powerful technique to characterize anisotropic materials with sub micro meter resolution. The use of polarized light allows one to obtain precise information about the local organization of the relevant molecular groups through the determination of the most probable distribution function. Such polarization analysis can be conducted under a confocal microscope, but caution must be exercised because of the use of objectives of high numerical value. The molecular orientation can be effectively correlated with the topography of the sample when atomic force microscopy experiments are conducted on the same object. In the present review paper, we present Raman imaging results that have been conducted on mesostructured polymer surfaces and on a single isolated semiconductor nanowire.Key words: Raman spectroscopy, confocal microscopy, orientation parameters, azopolymers, nanowires.
Examining the structural changes in Fe2(CO)9 under high external pressures by Raman spectroscopy
Authors: Safa Muhieddine , Dong Zhaohui , Song Yang , Huang Yining
Published: December 2007

Pressure-induced structural changes in di-iron nonacarbonyl [Fe2(CO)9] were examined by in situ Raman spectroscopy with the aid of a diamond anvil cell. Our results indicate that Fe2(CO)9 undergoes a pressure-induced phase transformation at about 0.9 GPa. Upon further compression, another structural transformation is identified at 7 GPa. In the low-pressure phase below 0.9 GPa, the π back-bonding between metal and carbonyl increases with increasing pressure. In the high-pressure phase above 7 GPa, the combination of high-pressure and laser irradiation induces a change in structure from Fe2(CO)9 to Fe2(CO)8. Fe2(CO)8 appears to adopt a structure with C2v rather than D3d or D2h symmetry. The metal–metal bond is gradually weakened under high pressures, and Fe2(CO)8 eventually decomposes by breaking the Fe–Fe bond when compressed up to 17.7 GPa.Key words: metal carbonyl, Raman spectroscopy, high pressure, diamond anvil cell.
Comparison of the distributions of bromine, lead, and zinc in tooth and bone from an ancient Peruvian burial site by X-ray fluorescence
Authors: Martin Ronald R , Naftel Steven J , Nelson Andrew J , III William D. Sapp
Published: December 2007

Synchrotron micro X-ray fluorescence was used to study the distribution of selected trace elements (Zn, Pb, and Br) in tooth and bone samples obtained from an individual from a pre-Columbian archaeological site (Cabur) located on the north coast of Peru. The results show that Zn, Pb, and Br are present in both the teeth and bone samples and that the Zn and Pb seem to be confined to similar regions (cementum and periostium), while Br shows a novel distribution with enrichment close to the Haversian canals and (or) in regions that appear to be Ca deficient.Key words: teeth, bone, metals, XRF, Br, Zn, and Pb.
Cross-linking organic semiconducting molecules by preferential C-H cleavage via “chemistry with a tiny hammer”
Authors: Lau W M , Zheng Z , Wang Y H , Luo Y , Xi L , Wong K W , Wong K Y
Published: December 2007

In the context of collision-induced dissociation in chemistry and kinematics in physics, we have determined that a beam of hyperthermal protons can be used as tiny hammers to preferentially break the C-H bonds of hydrocarbon precursor molecules adsorbed on a conductive substrate with little damage to other chemical bonds. The activated molecules are thereby converted to a cross-linked molecular network, with its chemical properties tailored by the preservation of the chemical functional groups of the precursors and with its physical properties tuned by the degree of cross-linking. This chemistry with a tiny hammer process is adopted to induce inter-chain cross-linking of the semiconducting molecular chains in poly (3,4-ethylenedioxythiophene) molecular films and to raise the electrical conductivity and stability of the molecular films. The results exemplify the unusual reaction design of this process as well as its application in electronic and optoelectronic device fabrication. The application is particularly attractive because the process does not require any chemical additives or catalysts other than a beam of protons, and it needs no thermal budget.Key words: organic semiconductor, polymeric semiconductor, cross-linking, polymer, collision, dissociative collision, molecular electronics, device fabrication.
Geometries and energetics of methanol–ethanol clusters: a VUV laser/time-of-flight mass spectrometry and density functional theory study
Authors: Liu Y , Consta S , Ogeer F , Shi Y J , Lipson R H
Published: December 2007

Hydrogen-bonded clusters, formed above liquid methanol (Me) and ethanol (Et) mixtures of various compositions, were entrained in a supersonic jet and probed using 118 nm vacuum ultraviolet (VUV) laser single-photon ionization/time-of-flight mass spectrometry. The spectra are dominated by protonated cluster ions, formed by ionizing hydrogen-bonded MemEtn neutrals, m = 0–4, n = 0–3, and m + n = 2–5. The structures and energetics of the neutral and ionic species were investigated using both the all-atom optimized potential for liquid state, OPLS-AA, and the density functional (DFT) calculations. The energetic factors affecting the observed cluster distributions were examined. Calculations indicate that the large change in binding energy going from trimer to tetramer can be attributed more to pair-wise interactions than to cooperativity effects.Key words: alcohol clusters, cluster formation, DFT calculations, mass spectrometry, vacuum ultraviolet laser.
Characterization of metallurgical-grade aluminas and their precursors by 27Al NMR and XRD
Authors: Perander Linus M , Zujovic Zoran D , Groutso Tania , Hyland Margaret M , Smith Mark E , ODell Luke A , Metson James B
Published: December 2007

The structure of metallurgical- or smelter-grade aluminas (MGAs) is complex and poorly understood. Ultra-high-field solid-state 27Al NMR results on industrial as well as on laboratory-prepared aluminas are discussed in relation to XRD results. It is demonstrated that high-field NMR can effectively be used to quantify the proportion of the thermodynamically stable alpha-alumina phase in these materials. The results demonstrate that 27Al NMR is a vital adjunct to XRD methods to quantify the transition alumina phases that invariably dominate the MGAs. The nature of the disorder in these materials, determined by 27Al NMR, is also compared with literature data, such as XANES and EXAFS studies, on typical laboratory-prepared materials. The utility of 27Al NMR studies to provide new insight into the structural complexity of metallurgical aluminas is shown.Key words: solid-state magic-angle-spinning NMR, metallurgical-grade alumina, transition alumina, gamma-alumina, coordination number.
Remarkable two-step, four-electron oxidative addition reactions at phosphorus [P(I)–P(V)] in terminal electrophilic phosphinidene complexes
Authors: Graham Todd W , Udachin Konstantin A , Zgierski Marek Z , Carty Arthur J
Published: December 2007

The reactivity of the terminal phosphinidene complex [Re(CO)5{η1-P(NiPr2)}]AlCl4 towards the oxidants S8 and Me3SnN3 has been investigated. These result in unprecedented four-electron oxidative addition reactions, affording complexes containing the P(V) ligands η1-P(=S)(Cl)(NiPr2) and η1-P(=NR)(Cl)(NiPr2), respectively. DFT calculations support the proposed mechanism.Key words: electrophilic phosphinidene, low coordinate phosphorus, rhenium, oxidative addition, P(I) ligand.
SINGAPORE'S EXCHANGE RATE POLICY: SOME IMPLEMENTATION ISSUES
Authors: CHOW HWEE-KWAN
Published: December 2007

Reflecting the small open nature of its economy, Singapore has adopted an exchange rate-centered monetary policy framework since 1981. The exchange rate regime in Singapore is an intermediate regime that follows the basket-band-crawl system. With this managed float system, the MAS has successfully deterred speculators from attacking the domestic currency for most of the past three decades. At the same time, the flexibility accorded by the managed float system aided Singapore in escaping from the 1997–1998 Asian crisis relatively unscathed. In order to advance our understanding of the hitherto successful operation of Singapore's exchange rate policy, we examine the following three aspects of its implementation: (i) the use of the exchange rate instead of the interest rate as the key monetary policy instrument; (ii) the management of the currency basket in terms of foreign exchange intervention operations; and (iii) regulating the level of domestic liquidity alongside exchange rate policy. This paper also provides some insights on the challenges ahead that potentially face policymakers when implementing Singapore's exchange rate policy.
JAPAN'S DEFLATIONARY HANGOVER: WAGE STAGNATION AND THE SYNDROME OF THE EVER-WEAKER YEN
Authors: MCKINNON RONALD
Published: December 2007

Japan still suffers a deflationary hangover from the great episodic yen appreciations of the 1980s into the mid-1990s. Money wages are still declining, and short-term interest rates remain trapped near zero. After Japan's "lost decade" from 1992 to 2002, however, output has begun to grow modestly — but through export expansion and associated investment rather than domestic consumption. This export-led growth has been helped by a passive real depreciation of the yen: prices and wages in Europe and the United States have grown, and are growing, faster than in Japan. As the yen becomes weaker in real terms, American and European industrialists and politicians are again complaining that the yen is too weak (Japan bashing II?) — although the pressure on Japan to appreciate is not yet as great as it now is on China.

But Japan is trapped. If it does appreciate the yen, its fragile economy will be driven back into outright deflation. The only solution is to stabilize the nominal dollar value of the yen over the long-term, but this step will not necessarily be immediately effective in placating foreign mercantilists. Under foreign pressure to appreciate the renminbi, China, with its booming economy, is now in a similar position to Japan's of more than 20 years ago. Policymakers in China should resist pressure to go down the same deflationary road as Japan.
THE FOG ENCIRCLING THE RENMINBI DEBATE
Authors: CHEUNG YIN-WONG , CHINN MENZIE D. , FUJII EIJI
Published: December 2007

We assess some recently advanced arguments for the claim that the RMB is undervalued. These arguments are those based on the direct valuation of the RMB, trade imbalances, the accumulation of foreign exchange reserves, and the degree of policy dependence. The extant evidence does not support a strong verdict regarding RMB undervaluation that meets the statistical standards of academic empirical studies. One interpretation is that the evaluation of the equilibrium RMB exchange rate is far more complicated than it appears. Another view is that the data are insufficiently informative. Some related policy concerns are also discussed.
ELASTICITY AND STABILITY OF A HELICAL FILAMENT WITH SPONTANEOUS CURVATURES AND ISOTROPIC BENDING RIGIDITY
Authors: ZHOU ZICONG , JOÓS BÉLA , LAI PIK-YIN , YOUNG YUAN-SHIN , JAN JENG-HUEI
Published: December 2007

We derive the shape equations in terms of Euler angles for a uniform elastic rod with isotropic bending rigidity and spontaneous curvature, and study within this model the elasticity and stability of a helical filament under uniaxial force and torque. We find that due to the special requirements on the boundary conditions, a static slightly distorted helix cannot exist in this system except in some special cases. We show analytically that the extension of a helix may undergo a one-step sharp transition. This agrees quantitatively with experimental observations for a stretched helix in a chemically-defined lipid concentrate (CDLC). We predict further that under twisting, the extension of a helix in CDLC may also exhibit similar behavior. We find that a negative twist tends to destabilize a helix.
SPIN HELIX IN THE PRESENCE OF EXTERNAL MAGNETIC FIELD
Authors: REN L.
Published: December 2007

For a two-dimensional electron gas with equal Rashba and Dresselhaus spin-orbit coupling strength (ReD model), and the Dresselhaus [110] model, the influence of an external magnetic field on the lifetime of the Spin Helix (SH) has been considered. A perpendicular magnetic field has no influence on the lifetime of the SH for the Dresselhaus [110] model, independent of the strength of the magnetic field. But for the ReD model, when the magnetic field is weak, and we only take the linear term of the magnetic field B into account, the conclusion is still so. In addition, if the external magnetic field is in-plane with a suitable angle between the x and y component, the lifetime of the SH will also be infinite.
CURRENT-MODE ACTIVE-C FILTER EMPLOYING REDUCED NUMBER OF CCCII+s
Authors: MINAEI SHAHRAM , YUCE ERKAN
Published: December 2007

In this paper, a universal current-mode second-order active-C filter for simultaneously realizing low-pass, band-pass and high-pass responses is proposed. The presented filter employs only three plus-type second-generation current-controlled conveyors (CCCII+s). This filter needs no critical active and passive component matching conditions and no additional active and passive elements for realizing high output impedance low-pass, band-pass and high-pass characteristics. The angular resonance frequency (ω0) and quality factor (Q) of the proposed resistorless filter can be tuned electronically. To verify the theoretical analysis and to exhibit the performance of the proposed filter, it is simulated with SPICE program.
THEORETICAL AND EXPERIMENTAL EVALUATION OF THE PHASE NOISE BEHAVIOR OF A DUAL-LOOP FREQUENCY SYNTHESIZER FOR 5-GHz WLANs
Authors: PLESSAS FOTIS , VATTI SOFIA , KALIVAS GRIGORIOS
Published: December 2007

This paper presents the analysis and experimental evaluation of a modified dual-loop phase-locked loop synthesizer, using the phase noise transfer functions resulting from the linear model of the synthesizer. The different arrangement in the high-frequency loop, in contrast to previous reported series-connected dual-loop topologies, offers various advantages, such as improved phase noise, finer resolution, and lower spurious levels. Discrete elements are used to implement a prototype system for testing. This adds to the flexibility of the design and allows for experimental optimization of the loop trade-offs. The synthesizer generates signals in the 4850 MHz to 5050 MHz range with a 10 MHz resolution and can match the specifications for wireless LANs operating at 5 GHz. The design resulted in a prototype with very good characteristics suitable for future integration.
A HIGH-PERFORMANCE SEQUENTIAL MRU CACHE USING VALID-BIT ASSISTANT SEARCH ALGORITHM
Authors: CHEN HSIN-CHUAN , CHIANG JEN-SHIUN
Published: December 2007

Most recently used (MRU) cache is one of the set-associative caches that emphasize implementation of associativity higher than 2. However, the access time is increased because the MRU information must be fetched before accessing the sequential MRU (SMRU) cache. In this paper, focusing on the SMRU cache with subblock placement, we propose an MRU cache scheme that separates the valid bits from data memory and uses these valid bits to decide to reduce the unnecessary access number of memory banks. By this approach, the probability of the front hits is thus increased, and it significantly helps in improving the average access time of the SMRU cache without valid-bit assistant search especially for large associativity and small subblock size.
DESIGN OF CROSS-COUPLED RESONATOR FILTERS WITH PARALLEL RESONANCE CIRCUITS
Authors: ZHAO BAISHAN , CHEN WAI-KAI
Published: December 2007

A method to design a cross-coupled resonator filter with parallel resonance circuits is presented, which includes the selection of a circuit model, introduces a scaling factor and a bandwidth condition, and calculates the values of the coupling and resonance admittances of the circuit model by a coupling matrix derived from the given transfer function. Finally, an example is given to illustrate the design procedure. The simulation results validate the proposed design procedure.
A BLOCK COPROCESSOR FOR USER DATA RATE IMPROVEMENTS TO GPRS CODING SCHEME 4
Authors: SHERRATT R. SIMON , ZHANG KAI , WILKES OWEN J.
Published: December 2007

The general packet radio service (GPRS) has been developed to allow packet data to be transported efficiently over an existing circuit-switched radio network, such as GSM. The main application of GPRS are in transporting Internet protocol (IP) datagrams from web servers (for telemetry or for mobile Internet browsers). Four GPRS baseband coding schemes are defined to offer a trade-off in requested data rates versus propagation channel conditions. However, data rates in the order of > 100 kbits/s are only achievable if the simplest coding scheme is used (CS-4) which offers little error detection and correction (EDC) (requiring excellent SNR) and the receiver hardware is capable of full duplex which is not currently available in the consumer market. A simple EDC scheme to improve the GPRS block error rate (BLER) performance is presented, particularly for CS-4, however gains in other coding schemes are seen. For every GPRS radio block that is corrected by the EDC scheme, the block does not need to be retransmitted releasing bandwidth in the channel and improving the user's application data rate. As GPRS requires intensive processing in the baseband, a viable field programmable gate array (FPGA) solution is presented in this paper.
A SIMPLE 1.5 V RAIL-TO-RAIL CMOS CURRENT CONVEYOR
Authors: KASEMSUWAN VARAKORN , NAKHLO WEERACHAI
Published: December 2007

A simple 1.5 V rail-to-rail CMOS current conveyor is presented. The circuit is developed based on a complementary source follower with a common-source output stage. The circuit is designed using a 0.13 μm CMOS technology and HSPICE is used to verify the circuit performance. The current conveyor exhibits low impedance at terminal X (7.2 Ω) and can drive ± 0.6 V to the 300 Ω with the total harmonic distortion of 0.55% at the operating frequency of 3 MHz. The voltage transfer error (between the Y and X terminals) and current transfer error (between the X and Y terminals) are small (-0.2 dB). The power dissipation and bandwidth are 532 μW and over 300 MHz, respectively.
GROUNDED CAPACITOR CM-APS WITH HIGH OUTPUT IMPEDANCE
Authors: MAHESHWARI SUDHANSHU
Published: December 2007

This paper presents a new first order current mode all-pass section (CM-APS) with a grounded capacitor and employing a modified current controlled conveyor. The new circuit with high output impedance is ideal for current-mode cascading and is tunable through an external bias current. The proposed circuit is unique due to its features, not exhibited by any of the available works on the topic. An application of the circuit in realizing a quadrature oscillator is also given. The theory is validated through PSPICE simulations using real device transistors.
MEMORY EFFICIENT IMPLEMENTATION OF AES S-BOXES ON FPGA
Authors: AZIZ ARSHAD , IKRAM NASSAR
Published: December 2007

Optimized implementation of computationally intensive cryptographic transformation is an area of active research, mainly focused on Advanced Encryption Standard (AES). Byte substitution implemented using substitution boxes (S-boxes), is the main transformation in AES which strains the enabling embedded platform, e.g., Field Programmable Gate Arrays. We represent a novel clocking technique enabling optimized implementation of Byte Substitution that enhances processing speed and reduces the area required for S-boxes on Xilinx FPGA Block RAM (BRAM).
A CONFIGWARE APPROACH FOR HIGH-SPEED PARALLEL ANALYSIS OF GENOMIC DATA
Authors: LOPES HEITOR S. , ERIG LIMA CARLOS R. , MURATA NORTON J.
Published: December 2007

Many problems in bioinformatics represent great computational challenges due to the huge amount of biological data to be analyzed. Reconfigurable systems can offer custom-computing machines, with orders of magnitude faster than regular software, running in general-purpose processors. We present a methodology for using a configware system in an interesting problem of molecular biology: the splice junction detection in eukaryote genes. Decision trees were developed using a benchmark of DNA sequences. They were converted into logical equations, simplified, and submitted to a Boolean minimization. The resulting circuit was implemented in reconfigurable parallel hardware and evaluated with a five-fold cross-validation procedure, run in a second level of parallelism. The average accuracy achieved was 90.41% and it takes 18 ns to process each data record with 60 nucleotides.
Short Sales Constraints and Return Volatility: Evidence from the Chinese A and H Share Markets
Authors: Gu Anthony Yanxiang , Yang Chauchen
Published: December 2007

Returns of the same companies' common stocks, both non-market-adjusted and market-adjusted, exhibit greater volatility, on the Stock Exchange of Hong Kong where short selling is allowed than on the Shanghai Stock Exchange and Shenzhen Stock Exchange where short selling is restrained. This unique evidence indicates that short selling increases stock price volatility for the Chinese stocks in the Chinese stock markets.
Establishing a Pecking Order for Finance Academics: Ranking of US Finance Doctoral Programs
Authors: Heck Jean L.
Published: December 2007

The ranking of colleges, programs, departments and faculties has reached a feverish pitch in recent years. Missing from the vast list of rankings is research covering doctoral programs in finance. This study ranks 91 US finance doctoral programs based on productivity of current finance department faculty, graduates of those programs, and a survey of doctoral program directors/chairs. The resulting rankings should be of value to those seeking to earn a finance doctorate in the future as well as satisfy the natural curiosity of finance faculty regarding bragging rights on their respective doctoral programs.
Earnings Management and the Pricing of Initial Public Offerings
Authors: Nagata Kyoko , Hachiya Toyohiko
Published: December 2007

This study investigates whether the extent of earnings management has any impact on offer price in initial public offering (IPO). Using a sample of 581 JASDAQ IPO firms, we find that offer price reflects earnings management to some extent. Firms with conservative earnings management tend to have higher offer prices, and firms managing earnings aggressively tend to be discounted when they fail to exhibit smooth earnings growth. These results are consistent with the hypothesis that underwriters adjust for the effect of earnings management to appropriately pricing the issues. Overall, our evidence could lead to another explanation for IPO underpricing.
Ownership Restriction, Information Diffusion Speed, and the Performance of Technical Trading Rules in Chinese Domestic and Foreign Shares Markets
Authors: Li Wei , Wang Steven Shuye
Published: December 2007

We examine the performance of technical trading rules in Chinese domestic A-share and foreign B-share markets. After controlling for non-synchronous trading and transaction costs, we find evidence to support the predictability and profitability of some of the most popular technical trading rules for B-shares but not for A-shares. However, after February 19, 2001, when domestic investors were allowed to trade B-shares, the predictive power of the trading rules in B-share markets disappeared. We conjecture that the predictability of technical trading rules in B-share markets can be attributed to the gradual diffusion of information among foreign investors under the foreign share ownership restriction, and, partly, to positive autocorrelations induced by thin trading.
Chapter 4 Pre-Tertiary stratigraphy
Authors: Barber A. J. , Crow M. J.
Published: December 2007

In the early days of mineral exploration on behalf of the Netherlands East Indies Bureau of Mines and of petroleum exploration by the oil companies it was recognized that Pre-Tertiary rocks were extensively exposed in the Barisan Mountains in the western part of Sumatra (Fig. 1.4). These rocks are variably metamorphosed and were termed the 'Barisan-Schiefer' and the 'Old-Slates Formation' (Veerbeek 1883) in Central Sumatra, and the 'Crystalline Schists' in the Lampung area (Westerveld 1941). Locally these rocks contain fossils, and it was recognized that Carboniferous and Permian rocks occur within this Pre-Tertiary basement. Some basement units were defined during the mapping of Sumatra by the Netherlands Indies Geological Survey between 1927 and 1931, but the definition of units according to modern stratigraphic principles began in the early 1970s, with the commencement of systematic mapping by the Indonesian Geological Survey in collaboration with the United States Geological Survey, in the Padang area of West Sumatra (Kastowo & Leo 1973-Padang; Silitonga & Kastowo 1975-Solok; Rosidi
et al.
1976-Painan and Muarasiberut).

Mapping and the definition of further units was continued in northern Sumatra by the Indonesian Directorate of Mineral Resources/British Geological Survey (DMR/BGS) between 1975 and 1980 as part of the Northern Sumatra Project and was extended into southern Sumatra in the 1980s and 1990s by the Indonesian Geological Research and Development Centre (GRDC), DMR amd BGS. The results of these surveys, which established the distribution of the basement units, are published by GRDC as 1:250 000 Geological Map Sheets covering the
Chapter 5 Granites
Authors: Cobbing E. J.
Published: December 2007

Knowledge of the granites of Sumatra has been gathered mainly as the result of systematic mapping programmes conducted with the aim of identifying mineral resources and providing a geological data base for more detailed studies. Mapping programmes were conducted principally by Dutch and Indonesian geologists prior to the second world war, mainly in southern Sumatra and the Tin Islands. In the 1970s a combined Indonesian Directorate of Mineral Resources (DMR)/British Geological Survey (BGS) project was set up to map the geology of Sumatra to the north of the Equator. On completion of this project in the mid-1980s geological and geochemical maps for the region were published at the scale of 1:250 000, together with descriptive sheet bulletins. Another useful compilation which may be refered to is the 1:2.5 million scale geological map for the whole of the Indonesian Archipelago which includes Sumatra (Clarke 1990).

Subsequently BGS undertook a similar but smaller project in southern Sumatra in order to upgrade geological mapping and mineral exploration programmes which were being conducted by the Indonesian Geological Research and Development Centre (GRDC) and DMR. As part of this programme a specific effort was made to investigate the granites of this region. A combined granite workshop/regional mapping programme resulted in the identification of many granite units within batholiths such as Lassi, Bungo and Garba, as well as numerous isolated plutons. Full geochemical and isotopic analyses were provided for these granites (McCourt & Cobbing 1993; McCourt
et al
. 1996). Gasparon & Varne (1995) have provided further
Chapter 7 Tertiary stratigraphy
Authors: De Smet M. E. M. , Barber A. J.
Published: December 2007

The purpose of this account is to review the complex terminology of the Tertiary stratigraphic units in Sumatra and propose a revised and a simplified terminology based on the significance of formations for the tectono-stratigraphic development of the island. Formations are classified in terms of Pre-Rift, Horst and Graben, Transgressive, and Regressive tectono-stratigraphic stages.

The island of Sumatra lies along the southwestern margin of the SE Asian continent (Sundaland) beneath which the Indian Ocean Plate is currently being subducted at a rate of about 7 cm a
-1
in the Sunda Trench (Fig. 7.1). The continental margin of SE Asia is of Andean type, with active and inactive Quaternary volcanoes rising to over 3000 m above a Pre-Tertiary basement, exposed towards the west coast of the island in the Barisan Mountains. Tertiary sedimentary basins occur both to the SW and the NE of the mountains and small basins also occur within the mountain range itself. These basins are described with relationship to the present-day subduction system as forearc, backarc and intra-arc or intramontane basins (Fig. 7.1). The Barisan Mountains are transected by the Sumatran Fault System, a major dextral transcurrent fault zone which extends along the length of the island from the Sunda Strait to the Andaman Sea.

Stratigraphic research in the Tertiary sedimentary basins commenced in the last decades of the nineteenth century when oil was discovered in the Telaga Tiga (1883) and Telaga Said (1885) wells near Pangkalan Brandan in North Sumatra. Initially, wildcat drills were sited near oil
Chapter 8 Tertiary volcanicity
Authors: Crow M. J.
Published: December 2007

The Centenary of the Netherlands Indies Geological Survey was commemorated by the publication of a synthesis of the geology of Indonesia by van Bemmelen (1949). In his account of the geology of Sumatra van Bemmelen (1949) described three distinct, but continuous, cycles of volcanic activity during the Tertiary and Quaternary: Old Neogene (Late Oligocene-Mid-Miocene); Young Neogene (Mid-Miocene-early in the Quaternary); and Young Quaternary. The first cycle began with the 'Old Andesites', and ended with the Mid-Miocene uplift of the Barisan Mountains. The second cycle commenced with the eruption of basic igneous products and concluded with an acidic phase which coincided with a second episode of uplift of the Barisan Mountains.

Subsequently, knowledge of the Tertiary volcanic rocks in Sumatra has been refined as the result of programmes of geological mapping in the early 1970s by the Geological Survey of Indonesia and the United States Geological Survey, and between 1975 and the mid-1990s by the Geological Research and Development Centre, the Directorate of Mineral Resources and the British Geological Survey. Exploration by oil and mineral companies has also provided data concerning the distribution of Tertiary plutonic rocks in the Pre-Tertiary basement and in the Tertiary sedimentary basins, of volcanic units interbedded with sediments. Further contributions to the understanding of Tertiary volcanicity in Sumatra and its forearc islands have been made by academic researchers and post-graduate students from the Institute of Technology, Bandung and the University of London, in collaboration with the Geological Research and Development Centre, LIPI and LEMIGAS, and the
Chapter 10 Fuel resources: oil and gas
Authors: Clure John
Published: December 2007

Petroleum systems are controlled by the evolution of sedimentary basins and the provenance of their sedimentary fills. As the result of a favourable combination of these factors Sumatra is rich in petroleum resources. The discovery and exploitation of commercial accumulations of oil and gas has so far been restricted to the backarc region of Sumatra, NE of the Barisan Range and the active volcanic arc, where three major sedimentary basins, the North, Central and South Sumatra Basins are distinguished. Exploration in the Sibolga, Mentawai and Bengkulu basins along the western margin of Sumatra in the forearc region has, so far, not been as successful. Commercial success has also eluded companies which have explored basins or sub-basins, such as the Ombilin Basin, which occur within the Barisan Range.

Plate-tectonic mechanisms and the resultant crustal thicknesses control this distribution of the Sumatran petroleum resources. To the east of the Barisan Range, beneath the backarc basins, the crust has been stretched and thinned and thus has a high geothermal gradient, suitable for the generation of hydrocarbons. In the forearc region, to the west of the Barisan Range, the lithosphere is thicker due to the subduction of the Indian Ocean Plate beneath the Sunda Craton in Sumatra. This effective doubling of lithospheric thickness has resulted in lowering of the geothermal gradient, so that sediments in the forearc basinal setting have a lower thermal maturity. Also, clastic sediments in forearc basins, due to their volcanic and metamorphic provenance, tend to be poor in quartz, and
Chapter 14 Tectonic Evolution
Authors: Barber A. J. , Crow M. J. , De Smet M. E. M.
Published: December 2007

The concept that SE Asia, and indeed Asia as a whole, has been built up during the Phanerozoic by the amalgamation of allochthonous terranes derived from the northern margin of East Gondwana, is now well established in the literature (e.g. Audley-Charles 1988; Sengor
et al
. 1988; Metcalfe 1996, 1999 and references therein). In Early Permian time all the major continental land masses, including East and West Gondwana, were joined together in the supercontinent of Pangaea (Fig. 14.1). At this time the continental blocks of North and South China, Indochina and Simao had already separated from East Gondwana. In Metcalfe's (1999) version of the concept a series of elongated terranes separated successively from the northern Gondwana margin by the development of ocean basins behind them. These oceans are referred to as Palaeo-Tethys, Meso-Tethys and Ceno-Tethys.

The Indochina Block, with East Malaya, forms the core of SE Asia and is considered to have separated from Gondwana by Late Devonian times to amalgamate with the South China Block by the Early Carboniferous. Indochina is characterized by an Upper Palaeozoic to Mesozoic fauna and flora of Cathaysian and Tethyan type, exemplified by the
Gigantopteris
flora of Jengka Pass (Kon'no & Asama 1970; Hutchison 1994), related to those of the North and South China blocks, but with no relationship to the flora and fauna of Gondwana. To this core was added the Shan-Thai or Sibumasu Block, which separated from Gondwana in the Permian and amalgamated with the Indochina Block in the Late Permian or Triassic
Rock physics and geomechanics in the study of reservoirs and repositories
Authors: David C. , Le Ravalec-Dupin M.
Published: December 2007

Reservoir management for hydrocarbon extraction and repositories design for radioactive waste storage are two different areas in which rock physics and geomechanics provide valuable information. Although the targets and objectives are different, similar approaches and common attributes exist in both fields: safety assessment, short- to long-term prediction, integration of various scales of investigation, and remote monitoring, among others. Nevertheless, there are also important differences: reservoirs at depth are investigated through remote geophysical studies, well-logging and/or core samples retrieval, whereas direct access to repositories is possible through excavation in the host formation in which underground research laboratories can be constructed. We review a number of studies focusing on geomechanics and rock physics applied to the characterization of reservoirs and repositories, including laboratory experiments and predictive models, at different scales.