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High-temperature oxide scales on two low-alloy steels were carefully studied. For the first time, the FeO inner scale on the steel with low Cr and Si contents is observed to incur a eutectoid reaction in a divorced mode during cooling, resulting into a bimodal Ni distribution near the scale/substrate interface. In contrast, a combination reaction of oxygen and FeO layer occurs on the steel with high Cr and Si contents where cracks in scales provide pathway for oxygen transport, and a fine-grained nanocomposite oxide band develops near the interface. Dealloying, partition and segregation during the scale formation are comprehensively addressed.

Based on the theory of mixing enthalpy of i,j element pairs (ΔHij) and atomic-size difference δ, we designed a uranium-containing equiatomic UHfNbTi high-entropy alloy with a single-phase bcc structure. The alloy showed good room-temperature compressive plastic properties. They with stood at least 60% of compression strain without fracture. We investigated the effect of average valence electron concentration (VEC) on the mechanical properties of the alloy. Reducing the VEC number is expected to produce uranium-containing high-entropy alloys with high ductility.

Summary Detailed experimental studies on the seismic properties of shale samples from different reservoirs have been conducted both in the laboratory and in situ under different conditions. In a previous study, Johnston and Wang (1981) measured the ultrasonic velocity anisotropy of Cretaceous shale in the Willison basin under undrained conditions. There are also indications that it is not only the amount of clay or organics, but also the shale maturity that controls the anisotropy (Vanorio et al., 2008; Ahmadov, 2010). Understanding the physical and petrophysical properties of shales and its influence factors are crucial as they strongly influence interpretations in seismic exploration, sonic logs, and microseismic monitoring. In spite of the growing interest in shale gas reservoirs for hydrocarbon exploration and production, and the strong influence that the petrophysical properties have on seismic response, there is still little laboratory data reported in the literature on the acoustic properties of shale samples from typical shale gas reservoir in China. Here, we present laboratory dataset for the Late Ordovician to the Early Silurian Wufeng-Longmaxi black shale in the southeast of the Sichuan Basin.

State-of-charge (SOC) estimation is one of the most challengeable tasks for battery management system (BMS) in electric vehicles. Since the external factors (voltage, current, temperature, arrangement of the batteries, etc.) are complicated, the formula of SOC is difficult to deduce and the existent SOC estimation methods are not generally suitable for the same vehicle running in different road conditions. In this paper, we propose a new SOC estimation based on an optimized support vector machine for regression (SVR) with double search optimization process. Our developed method is tested by simulation experiments in the ADVISOR, with a comparison of the estimations based on artificial neural network (ANN). It is demonstrated that our method is simpler and more accurate than that based on ANN to deal with the SOC estimation task.

Along with the continuous in-depth exploration, fractured reservoir in the exploration and development of oil and gas has been showing its importance. Fractures in reservoirs is reservoir space, but also can be used as the main passages for hydrocarbon migration and Communicate various pore space. Identification and prediction of fractured reservoir is very important for petroleum exploration and development. This article describes how to use the full-azimuth or wide-azimuth to collect data and get a full-azimuth common reflection angle gathers by offset. Then these gathers can be used to predict fracture with AVAZ pre stack inversion method and obtain the strength and direction of crack development for HTI medium. The accuracy by this method is higher than Post-stack attribute or pre-stack seismic sub range to predict fracture.

Systemically examine and study the dependant perception difference between enterprises in the supply chain environment and the influence for the coordinated behaviors of small and medium sized enterprises by such perception difference. Also the article conducts the demonstrated analysis and testing with the use of the pair data of coordinated enterprises of supply chain of the relevant industry supply chain in Xi'an district manufacturing.

An upper limit to the production of {sup 19}Ne through the {sup 18}F(p,{gamma}) reaction at the recently discovered s-wave resonance has been determined. The limit implies that in a hot stellar environment (T{sub 9} > 0.5) this reaction is not a significant gateway from the hot CNO cycle towards the production of heavier elements in stars.

Inclusive double differential multiplicities and rapidity density distributions of hadrons are presented for 10.8 A GeV/c Au+Au collisions as measured at the AGS by the E877 collaboration. The results indicate that large amounts of stopping and collective transverse flow effects are present. The data are also compared to the results from the lighter Si+Al system., Comment: 12 pages, latex, 10 figures, submitted to Nuclear Physics A (Quark Matter 1996 Proceedings)

The general ion-optics code GIOS is a very powerful and useful program for calculating the ion optics of an electromagnetic system. It was used extensively in the design and operation of the Fragment Mass Analyzer (FMA). In the original version of the program a feature is described which allows the initial beam density to be varied with angle, energy, mass, or position. In fact, this feature was never implemented, and only isotropic beam densities are available. In order to make more reliable calculations of reaction yields and FMA transport efficiencies, it is important to be able to use more realistic beam density distributions.

Reaction studies of interest to astrophysics with radioactive ion beams will be done mainly in inverse reaction kinematics, i.e., heavy particles bombarding a hydrogen target. The low energy of the outgoing heavy reaction products makes particle identification with respect to mass and nuclear charge a major challenge. For the planned {sup 18}F(p,{alpha}) experiment one expects five different types of particles in the outgoing channels: {sup 18}F and {sup 18}O (from elastic scattering of {sup 18}F and {sup 18}O on {sup 12}C), {sup 15}O and {sup 15}N (from the {sup 18}F and {sup 18}O induced (p,{alpha}) reactions) and {sup 12}C recoils from the polypropylene target. While mass determination can be achieved easily by time-of-flight (TOF) measurements, a determination of the nuclear charge presents a challenge, especially if the energy of the particles is below 500 keV/u. We studied the gas-filled magnet technique for Z-identification of light ions between Z = 6-9. In a gas-filled magnet the particles move with an average charge state {bar q} which in one parameterization is given by {bar q} = Z ln(avZ{sup {alpha}})/ln(bZ{sup {beta}}) where Z is the nuclear charge of the ions and v their velocity. Introducing into the expression for the magnetic rigidity B{rho}more » = mv/{bar q} results in a Z dependence of B{rho} which is valid to very low velocities. As a magnet we used the Enge split-pole spectrograph which was filled with nitrogen gas at a pressure of 0.5 Torr. The particles were detected in the focal plane with a 50 x 10 cm{sup 2} parallel-grid-avalanche counter which measured TOF and magnetic rigidity. The mass and Z separation was tested with {sup 13}C and {sup 18}O beams at energies of about 600 keV/u and recoil particles ranging from {sup 12}C to {sup 19}F. The Z-separation obtained at these energies was {triangle}Z/Z = 0.28 which is sufficient to separate individual elements for Z < 10.« less

Measurements of fusion excitation functions involving transitional nuclei {sup 78}Kr and {sup 100}Mo showed a different behavior at low energies, if compared to measurements with {sup 86}Kr and {sup 92}Mo. This points to a possible influence of nuclear structure on the fusion process. One way to characterize the structure of vibrational nuclei is via their restoring force parameters C{sub 2} which can be calculated from the energy of the lowest 2{sup +} state and the corresponding B(E2) value. A survey of the even-even nuclei between A = 28-150 shows strong variations in C{sub 2} values spanning two orders of magnitude. The lowest values for C{sub 2} are observed for {sup 78}Kr, {sup 104}Ru and {sup 124}Xe followed by {sup 74,76}Ge, {sup 74,76}Se, {sup 100}Mo and {sup 110}Pd. In order to learn more about the influence of {open_quotes}softness{close_quotes} on the sub-barrier fusion enhancement, we measured cross sections for evaporation residue production for the systems {sup 78}Kr + {sup 104}Ru and {sup 78}Kr + {sup 76}Ge with the gas-filled magnet technique. For both systems, fusion excitation functions involving the closed neutron shell nucleus {sup 86}Kr were measured previously. The data are presently being analyzed.

High resolution experiments performed during the past few years demonstrated that the various reaction modes occurring in heavy ion collisions can strongly influence each other. This interrelation of the different reaction modes brings a nuclear structure dependence to the fusion and deep-inelastic channels that were previously described in the framework of pure statistical models. In order to fully understand the interrelation between these reaction channels, a complete set of measurements including elastic and inelastic scattering, few-nucleon transfer and fusion is required. In continuation of our earlier measurements of the fusion cross sections in the system {sup 58,64}Ni + {sup 92,100}Mo we finished the studies of the quasielastic process in these systems. The experiments were done in inverse reaction kinematics using the split-pole spectrograph with its hybrid focal-plane detector for particle identification. The experiments with {sup 100}Mo beams were performed previously. First test runs with {sup 92}Mo showed the possible interference with {sup 98}Mo ions which could be eliminated by using the 13{sup +} charge state from the ECR source. The data from these experiments were completely analyzed. The smallest transfer cross sections are observed for the systems {sup 64}Ni + {sup 100}Mo and {sup 58}Ni + {sup 92}Mo, i.e., themore » most neutron-rich and neutron-deficient systems, respectively. For the other systems, {sup 64}Ni + {sup 92}Mo and {sup 58}Ni + {sup 100}Mo, the transfer cross sections at energies close to the barrier are about of equal magnitude. This observation does not correlate with the deviation of the experimental fusion cross sections from the coupled-channels predictions. While for {sup 58}Ni + {sup 100}Mo discrepancies between the experimental and theoretical fusion cross sections are observed, the system {sup 64}Ni + {sup 92}Mo which shows about the same transfer yields, is quite well described by the coupled-channels calculations.« less

Earlier measurements of fusion reactions involving {sup 78}Kr and {sup 100}Mo projectiles and Ni-targets showed surprisingly large fusion yields at low energies which could not be explained by coupled-channels calculations. The main difference to similar measurements involving the neighboring {sup 86}Kr and {sup 92}Mo isotopes was the different slope of the excitation functions at sub-barrier energies. An analysis of a variety of experiments showed a correlation between the nuclear structure and the slope of the excitation functions, with the {open_quotes}soft{close_quotes} transitional nuclei ({sup 78}Kr, {sup 100}Mo) exhibiting shallower slopes than the {open_quotes}stiff{close_quotes} nuclei ({sup 86}Kr, {sup 92}Mo) measured at the same energies with respect to the barrier. In this experiment we studied the fusion excitation function involving two transitional nuclei {sup 78}Kr + {sup 100}Mo. The measurements were performed with {sup 78}Kr beams from the ECR source at energies between 285-370 MeV. Separation of the evaporation nucleus from the elastically scattered particles was achieved by measuring time-of-flight and magnetic rigidity in the gas-filled spectrograph. The data were completely analyzed. A comparison of the cross sections with measurements for the system {sup 86}Kr + {sup 92}Mo populating the same compound nucleus {sup 178}Pt. It shows good agreement at the highest energies,more » but quite different falloffs of the excitation functions toward lower energies. Coupled-channels calculations, including multi-phonon excitation for the two systems, are being performed.« less

We investigated the nuclear structure dependence of the sub-barrier fusion enhancement in heavy-ion induced reactions by studying the systems {sup 58,64}Ni + {sup 78,86}Kr at energies in the vicinity of the Coulomb barrier. These {sup 78,86}Kr selected because, similar to the Mo case discussed isotopes were above, there are strong changes in nuclear structure as a function of the neutron number. However, contrary to Mo, where the {open_quotes}softness{close_quotes} of the nucleus increases with higher neutron number, the most collective nucleus for the Kr case is the neutron-deficient {sup 78}Kr. The experiment was performed with Kr beams from the positive-ion injector using enriched {sup 78,86}Kr gas in the ECR ion source. The separation of evaporation residues from the elastically-scattered particles was achieved by using their difference in time-of-flight and magnetic rigidity in the gas-filled spectrograph. The excitation functions for the four systems were compared to coupled-channels calculations including inelastic excitations of one- and two-phonon states in projectile and target. For systems involving {sup 86}Kr, good agreement between theory and experiment is obtained, while for {sup 78}Kr + {sup 58,64}Ni an additional enhancement of the cross sections persisted at the lowest energies. It was found that this fusion enhancement correlates with themore » nuclear structure of the individual nucleus. Characterizing the structure of vibrational even-even nuclei by their restoring force parameter C{sub 2}, which can be calculated from the energy of the lowest 2{sup +} state and the associated B(E2) value, one observes that nuclei with small C{sub 2} values exhibit a large sub-barrier fusion enhancement, while nuclei with high values of C{sub 2} (usually closed-shell nuclei), show smaller fusion yields.« less

Fusion reactions between different Kr and Ni isotopes were measured recently at ATLAS. We performed coupled-channels calculations and made comparisons to the measurements. Such calculations become increasingly difficult for heavy, soft nuclei due to strong couplings and the importance of higher-order, multi-step processes. The calculations were made possible by adopting the so-called rotating frame approximation, and they included one- and two-phonon excitations of the low-lying 2{sup +} and 3{sup -} states in both the projectile and the target. These calculations reproduced quite accurately the measured fusion cross sections for a beam of {sup 86}Kr. Some discrepancies remain for the much softer {sup 78}Kr nucleus; the calculations were clearly much more sensitive to higher-order processes in this case. In particular, it was important to implement the correct coupling strength and excitation energy for the soft, one- to two-phonon quadrupole transition in {sup 78}Kr, which differs significantly from the vibrational limit. This work was performed in collaboration with the experimentalists and was submitted for publication.

The detailed behavior of the newly observed heavy-ion fusion hindrance for systems with positive Q value is not yet known well. Does an S factor maximum occur also for these systems at very low energies? This is still an open question and is discussed in this presentation of the experimental activities.

An accurate, temperature-dependent model has been developed for the DC I-V characteristic of an InP-based double heterojunction (DH) laser by parameter extraction using the ideal diode equation model. The parameters of the ideal diode equation can then be used to determine junction quality and reproducibility. The change in device parasitic resistance has been measured and its temperature dependence found. A relationship between threshold current and ideality factor is proposed. The deviation between the measured and modeled I-V characteristic can be used to determine threshold current accurately, independently of optical measurements. >

Low threshold GaInAsP/InP Buried Optical Waveguide lasers emitting at 1.3 µm were successfully fabricated by two step liquid phase epitaxy. Room temperature CW threshold current as low as 59 mA (corresponding to ∼ 11 mA per micron active stripe width) and CW differential quantum efficiencies of 26%/facet was achieved. CW operation was achieved for these devices at heat sink temperatures as high as 70°C. A single transverse mode (∼ 13 to 20° angular divergence) was obtained at more than twice the threshold current. The mechanism for transverse mode stabilization is believed to result from scattering "losses" suffered by the higher order transverse modes at the buried mesa sidewalls. No relaxation oscillation was observed in their transient response.

We present the present status of the E877 studies of anisotropic transverse flow at the AGS energy. Flow is quantified by Fourier analysis of the azimuthal distributions of transverse energy and charged particle multiplicity. Additionally, the mean transverse momentum of identified particle spectra with respect to the reaction plane are measured near the beam rapidity. Analysis shows the presence of nucleon flow at AGS energies and a small pion flow in the direction opposite to that of the nucleon.

Fabrication of 1.55 μm InGaAsP buried-crescent (BC) injection lasers with a p-n-p-n blocking structure is described. The BC lasers exhibit a threshold current as low as 14 mA at 25°C, very high yield, output power more than 10 mW and high-temperature operation up to 80°C. These BC lasers have continued to operate in stable CW mode at 50°C for more than 1000 h. The lifetime of the 1.55 μm InGaAsP lasers at 50°C is estimated to exceed about 2.5 × 104 h.