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We present a method of measuring the in situ superficial seafloor sound speed by using two receivers deployed vertically in sediment, based on the dispersion characteristic of normal modes in shallow water. Warping transformation is adopted to extract the first normal mode from the broadband propagation signals. Some experimental results which could validate the method are shown. One of the advantages of the method is that the seafloor sound speed can be solved directly from the relative vertical transmission loss of the first normal mode without the exact priori information of the environmental parameters such as the sound speed profile, the water-column depth and the source location. [ABSTRACT FROM AUTHOR]

Co-doped TiO2 thin films are grown on TiN buffered silicon substrates by the pulsed laser deposition method and then hydrogenated. Transmission electron microscopy and high-angle annular dark-field scanning transmission electron microscopy measurements have shown that the TiN buffer layer can suffer a 400°C deposition temperature and prevent the growth of silicon dioxide on silicon. After that, the room temperature ferromagnetism behaviors are observed in the hydrogenated samples, which are measured by the alternating gradient magnetometer. X-ray photoelectron spectroscopy and x-ray absorption fine structure measurements have revealed the existence of cobalt clusters. According to the material analysis, the magnetic behavior after hydrogenation is suggested to be induced by the enhancement of cobalt clusters. [ABSTRACT FROM AUTHOR]

A strained-SiGe p-channel metal-oxide-semiconductor-field-effect transistors (p-MOSFETS) with higher-κ LaLuO3 gate dielectric was fabricated and electrically characterized. The novel higher-κ (κ∼30) gate dielectric, LaLuO3, was deposited by molecular-beam deposition and shows good quality for integration into the transistor. The transistor features good output and transfer characteristics. The hole mobility was extracted by the splitting C—V method and a value of 200cm2/V·s was obtained for strong inversion conditions, which indicates that the hole mobility is well enhanced by SiGe channel and that the LaLuO3 layer does not induce additional significant carrier scattering. Gate induced drain leakage is measured and analyzed by using an analytical model. Band-to-band tunneling efficiencies under high and low fields are found to be different, and the tunneling mechanism is discussed. [ABSTRACT FROM AUTHOR]

A novel silicon-on-insulator (SOI) high-voltage device of super-junction (SJ) lateral-double-diffused metal-oxide-semiconductor transistors (LDMOSTs) with T-dual dielectric buried layers (T-DBLs) is presented. The T-DBLs are formed by the first T-shaped dielectric layer and the second dielectric layer. A lot of holes are accumulated on the top interface of the second dielectric layer, which compensates for the charge imbalance of the surface N and P pillars, thus the substrate-assisted depletion (SAD) effect is eliminated in the new device. The electric field of the second dielectric buried layer, E12, is enhanced by the interface charges, and the breakdown voltage Vbreakdown is increased. E12 = 515 V/μm is obtained in the T-DBL SOI SJ. The Vbreakdown of the new device is increased from 124 V of the conventional SOI SJ to 302 V with a 15 μm length drift region. The specific on-resistance (Ron,sp) of the T-DBL SOI SJ is only 0.00865 Ω·cm2 and the FOM (FOM = V2breakdown/Ron,sp) is 10.54 MW/cm2. [ABSTRACT FROM AUTHOR]

Infrared reflectivity measurement is carried out for AlN films on sapphire substrates. The frequencies of the symmetry optical phonon E1(TO) in the temperature range from 77 K to 500 K are reported by fitting the experimental reflectivity with the classical multi-oscillators model. Taking the lattice thermal expansion and Klemens process of the phonon decay into account, along with the strain effect introduced by thermal mismatch between the film and the substrate, the temperature effect on the frequency of the optical phonon E1(TO) is revealed. It is shown that the shift of frequency is mainly attributed to the decay process while the strain effect induced by thermal mismatch plays a non-negligible role in the outcomes of the strength and damping parameters. [ABSTRACT FROM AUTHOR]

A novel silicon-on-insulator (SOI) metal-oxide-semiconductor field effect transistor (MOSFET) with a high figure of merit (FOM) is proposed. The device features a double-sided charge oxide-trench (DCT) and a trench gate extended to the buried oxide. First, the oxide trench causes multiple-dimensional depletion in the drift region, which not only improves the electric field (E-field) strength, but also enhances the reduced surface field effect. Second, self-adaptive charges are collected in the DCT, which enhances the E-field strength of the trench oxide. Third, the oxide trench folds the drift region along the vertical direction, reducing the device cell pitch. Fourth, one side of the DCT regions acts as the body contact of p-well to reduce cell pitch and specific on-resistance (Ron,sp) further. Compared with a trench gate lateral double-diffused MOSFET, the DCT MOSFET increases the breakdown voltage (BV) from 53 V to 158 V at the same cell pitch of 3.5 μm, or reduces the cell pitch by 60% and Ron,sp by 70% at the same BV. The FOM (FOM=BV2/Ron,sp) of the proposed structure is 23 MW/cm2. [ABSTRACT FROM AUTHOR]

Porous α-Fe2O3 nanowires are synthesized by a simple wet chemical method with a precursor of peroxyacetyl nitrate (PAN), and α-Fe2O3 nanoparticles are also synthesized in the same way except for the addition of PAN. Gas sensors are fabricated by coating the samples on ceramic tubes with Au signal electrodes and Ni-Cr heaters. A sensing investigation reveals that the porous α-Fe2O3 nanowires have a higher sensitivity compared to α-Fe2O3 nanoparticles at 260°C. The corresponding sensor response (RaRg) is 18.2 at the maximum to 100 ppm acetone, and the response and recovery times are about 8 and 12 s, respectively. The porous and one-dimensional nanostructures of the porous α-Fe2O3 nanowires benefit for the gas-absorption and electrical-signal-transfer, and thus improve the sensor sensitivity consequentially. [ABSTRACT FROM AUTHOR]

The junction temperature of red, green and blue high power light emitting diodes (LEDs) is measured by using the emission peak shift method and the forward voltage method. Both the emission peak shift and the forward voltage decrease show a linear relationship relative to junction temperature. The linear coefficients of the red, green and blue LEDs for the peak shift method and the forward voltage method range from 0.03 to 0.15 nm/ °C and from 1.33 to 3.59mV/ °C, respectively. Compared with the forward voltage method, the peak shift method is almost independent of bias current and sample difference. The variation of the slopes is less than 2% for the peak shift method and larger than 30% for the forward voltage method, when the LEDs are driven by different bias currents. It is indicated that the peak shift method gives better stability than the forward voltage method under different LED working conditions. [ABSTRACT FROM AUTHOR]

The neutron-capture process is traditionally postulated to be responsible for the nucleosynthesis of heavy elements beyond Fe. Based on the least squares method and solar isotopic abundances from the classical model, we estimate the relative contributions of the s- and r-processes to the abundance of neutron-capture elements in the metalpoor star HD 175305 from the component coefficients. Applying the calculated component coefficients Cr and Cs, the model predicts the isotopic fractions of elements Nd, Sm and Eu to be f142+144 = 0.482, f152+154 = 0.525 and f151 = 0.450, respectively. As well as the observed abundances, the isotropic fractions are also consistent with the calculations. Finally, for the first time, we estimated the contribution percentage of the two neutron processes (the r- and s-processes) from the observed isotopic fractions of different elements in HD 175305, e.g. an r-process contribution of 67%+21% -32% from the 4604Å line of Sm. [ABSTRACT FROM AUTHOR]

A spintronic near-field microwave imaging system without vector network analyzers is used to detect the distribution of microwaves, which are scattered by a sub-wavelength periodical metal wire grating. An ultra thin metal body with diameter of 100 μm (λ/300) is observed by imaging illuminated by a 10 GHz shining source. An application with high sensitivity and resolution detection is proposed in the microwave region under a weak applied external static magnetic field. [ABSTRACT FROM AUTHOR]

Short-channel high-mobility Si/Si0.5Ge0.5/silicon-on-insulator (SOI) quantum-well p-type metal-oxide-semiconductor field effect transistors (p-MOSFETs) were fabricated and electrically characterized. The transistors show good transfer and output characteristics with Ion/Ioff ratio up to 105 and sub-threshold slope down to 100mV/dec. HfO2/TiN gate stack is employed and the equivalent oxide thickness of 1.1 nm is achieved. The effective hole mobility of the transistors reaches 200cm2/V·s, which is 2.12 times the Si universal hole mobility. [ABSTRACT FROM AUTHOR]

Ultra high-velocity collisionless shocks are generated using an ultra-intense laser interacting with foil-gas target, which consists of copper foil and helium gas. The energy of helium ions accelerated by shock and the proton probing image of the shock electrostatic field show that the shock velocity is 0.02c, where c is the light speed. The numerical and theory studies indicate that the collisionless shock velocity exceeding 0.1c can be generated by a laser pulse with picosecond duration and an intensity of 1020W/cm2. This system may be relevant to the study of mildly relativistic velocity collisionless shocks in astrophysics. [ABSTRACT FROM AUTHOR]

We investigate nonlinear interaction of nitrogen molecules with a two-color laser field composed by an intense 800 nm laser pulse and a weak 400 nm laser pulse. It is demonstrated that the spectrum of 400 nm pulses is dramatically broadened when the two beams temporally overlap. In comparison, the spectral broadening in argon is less pronounced, although argon atoms and nitrogen molecules have comparable ionization potentials. We reveal that the dramatic spectral broadening originates from the greatly enhanced nonlinear optical effects in the near-resonant condition of interaction between the 400 nm pulses and the nitrogen molecular ions. [ABSTRACT FROM AUTHOR]

The band structures of two-monolayer Bi(110) films on black phosphorus substrates are studied using angle-resolved photoemission spectroscopy. Within the band gap of bulk black phosphorus, the electronic states near the Fermi level are dominated by the Bi(110) film. The band dispersions revealed by our data suggest that the orientation of the Bi(110) film is aligned with the black phosphorus substrate. The electronic structures of the Bi(110) film strongly deviate from the band calculations of the free-standing Bi(110) film, suggesting that the substrate can significantly affect the electronic states in the Bi(110) film. Our data show that there are no non-trivial electronic states in Bi(110) films grown on black phosphorus substrates. [ABSTRACT FROM AUTHOR]

We report an effective method to improve the formation of nickel stanogermanide (NiGeSn) by the incorporation of a platinum (Pt) interlayer. After the Ni/Pt/GeSn samples are annealed we obtain uniform NiGeSn thin films, which are characterized by means of sheet resistance, atomic force microscopy, scanning electron microscopy, cross-section transmission electron microscopy, and energy dispersive x-ray spectroscopy. These results show that the presence of Pt increases the smoothness and uniform morphology of NiGeSn films. [ABSTRACT FROM AUTHOR]

We investigate the effectiveness of the hopping parameter expansion (HPE) combined with the Z(2) noise method in the calculation of the trace of the inverse of Wilson’s Dirac operator and some other disconnected contributions. A numerical comparison of the standard deviation for the Z(2) noise method and HPE with the Z(2) noise method is carried out. It is found that there are noise reductions in all the quantities we calculated using the HPE with the Z(2) noise method. For the trace of the inverse of Wilson’s Dirac operator, the HPE can reduce the statistical error by about 60%. [ABSTRACT FROM AUTHOR]

The elliptic flow v2, for , , p andin Au+Au collisions at center-of-mass energies , 11.5, 14.5 and 19.6 GeV, is analyzed using a multiphase transport model. A significant difference in the v2values for p andis observed, and the values of v2splitting are larger compared withand , and . The difference increases with decreasing the center-of-mass energy. The effect of the quark coalescence mechanism in a multi-phase transport model to the value of elliptic differencebetween p andhas been discussed. The simulation of Au+Au collisions at 14.5 GeV shows that the effect of hadron cascade tois not obvious, and a larger parton-scattering cross section can lead to a larger . [ABSTRACT FROM AUTHOR]

Based on the frequency-to-time mapping relation of the linearly chirped pulse, the temporal phase shift induced by a laser-excited wake in a helium gas jet is measured using a chirped-pulse spectral interferometry with ~ 140 fs resolution over a temporal region of 1 ps in a single shot. In this measurement, the image of the wake is obtained with one-dimensional spatial resolution and temporal resolution limited only by the bandwidth and chirp of the pulse. The ‘bubbles’ feature of the wake structure, along with multiple wakes excited by the main lobe and the side lobe of a laser focal-spot, is captured simultaneously. [ABSTRACT FROM AUTHOR]

Nucleosynthesis in advection-dominated accretion flow (ADAF) onto a black hole is proposed to be an important role in chemical evolution around compact stars. We investigate the nucleosynthesis in ADAF relevant for a black hole of low mass, different from that of the self-similar solution. In particular, the presence of supersolar metal mass fractions of some isotopes seems to be associated with the known black hole nucleosynthesis in ADAF, which offers further evidence of diversity of the chemical enrichment. [ABSTRACT FROM AUTHOR]

We study a laser wakefield acceleration driven by mid-infrared (mid-IR) laser pulses through two-dimensional particle-in-cell simulations. Since a mid-IR laser pulse can deliver a larger ponderomotive force as compared with the usual 0.8 μm wavelength laser pulse, it is found that electron self-injection into the wake wave occurs at an earlier time, the plasma density threshold for injection becomes lower, and the electron beam charge is substantially enhanced. Meanwhile, our study also shows that quasimonoenergetic electron beams with a narrow energy-spread can be generated by using mid-IR laser pulses. Such a mid-IR laser pulse can provide a feasible method for obtaining a high quality and high charge electron beam. Therefore, the current efforts on constructing mid-IR terawatt laser systems can greatly benefit the laser wakefield acceleration research. [ABSTRACT FROM AUTHOR]

A lateral current regulator diode (CRD) with field plates is proposed and experimentally demonstrated. The proposed CRD is based on the junction field-effect transistor (JFET) structure. A cathode field plate is adopted to alleviate the channel-length modulation effect and to improve the saturated I—V characteristics. An anode field plate is induced to achieve a high breakdown voltage VB of the CRD. The influence of the key device parameters on the I—V characteristics of the lateral CRD are discussed. Experimental results show that the proposed CRD presents good I—V characteristics with a high VB about 180 V and a low knee voltage (Vk) below 3 V. Furthermore, the proposed CRD has a negative temperature coefficient. The well characteristic of the proposed CRD makes it a cost-effective solution for light-emitting-diode lighting. [ABSTRACT FROM AUTHOR]

We find for the first time that a model Hamiltonian of s-wave superconductors in the presence of spin-orbit interactions and a Zeeman field is exactly solvable. Most intriguingly, based on the exact solutions, a novel type of Fulde—Ferrel—Larkin—Ovchinnikov ground state is rigorously revealed, in which the center-of-mass momentum of the fermion pair is proportional to the Zeeman field. We also generalize our exact analysis to the spin-orbit-coupled Bose—Einstein condensate. [ABSTRACT FROM AUTHOR]