Molecular constants of LiCl(X1Σ+) and elastic collisions of two ground-state Cl and Li atoms at low and ultralow temperatures

Interaction potentials for LiCl(X¹Σ⁺) are constructed by the highly accurate valence internally contracted multireference configuration interaction in combination with a number of large correlation-consistent basis sets, which are used to determine the spectroscopic parameters (D₀, D_e, R_e, ω_e, _eχ_e, B_e and α_e. The potentials obtained at the basis sets, i.e., aug-cc-pV5Z-JKFI for Cl and cc-pV5Z for Li, are selected to study the elastic collision properties of Li and Cl atoms at the impact energies from 1.0×10^-12 to 1.0×10^-4 a.u. The derived total elastic cross sections are very large and almost constant at ultralow temperatures, and their shapes are mainly dominated by the s-partial wave at very low impact energies. Only one shape resonance can be found in the total elastic cross sections over the present collision energy regime, which is rather strong and obviously broadened by the overlap contributions of the abundant resonances coming from various partial waves. Abundant resonances exist for the elastic partial-wave cross sections until l = 22 partial waves. The vibrational manifolds of the LiCl(X¹Σ⁺) molecule, which are predicted at the present level of theory and the basis sets cc-pV5Z for Li and the aug-cc-pV5Z-JKFI for Cl, should achieve much high accuracy due to the employment of the large correlation-consistent basis sets.     

Effects of high-pressure heat treatment on the solid-state phase transformation and microstructures of Cu61.13Zn33.94Al4.93 alloys

The phase transformation activation energy of the Cu_61.13Zn_33.94Al_4.93 alloys, which were treated at 4 GPa and 700 °C for 15 minutes, was calculated by means of differential scanning calorimetry curves obtained at various heating and cooling rates. Then, the effects of high-pressure heat treatments on the solid-state phase transformation and the microstructures of Cu_61.13Zn_33.94Al_4.93 alloys were investigated. The results show that high-pressure heat treatments can refine the grains and can change the preferred orientation from (111) to (200) of α phase. Compared with the as-cast alloy, the sample with high-pressure heat treatment has finer grains, lower β' → β and β → β ' transformation temperature and activation energy. Furthermore, we found that high cooling rate favours the formation of fine needle-like α phase in the range of 5--20 °C/min.     

Influence of pressure on the solid state phase transformation of Cu—Al—Bi alloy

The solid state phase transformation of Cu--Al--Bi alloy under high pressure was investigated by x-ray diffraction, energy dispersive spectroscopy and transmission electron microscopy. Experimental results show that the initial crystalline phase in the Cu--Al--Bi alloy annealed at 750 °C under the pressures in the range of 0--6 GPa is α-Cu solid solution (named as α-Cu phase below), and high pressure has a great influence on the crystallisation process of the Cu--Al--Bi alloy. The grain size of the α-Cu phase decreases with increasing pressure as the pressure is below about 3 GPa, and then increases (P>3 GPa). The mechanism for the effects of high pressure on the crystallisation process of the alloy has been discussed.     

3D Effects on Vortex-Shedding Flow and Hydrodynamic Coefficients of A Vertically Oscillating Cylinder with A Bottom-Attached Disk

Vortex-shedding flow induced by the vertical oscillation of a cylinder with bottom-attached disks of different diameter ratio D_d/D_c and thickness ratio t_d/D_c is studied by a 3D (three-dimensional) numerical model developed in this paper, and compared with the results obtained through 2D (two-dimensional) numerical model. The high-order upwind scheme is applied to stabilize the computation, and convergence is accelerated by the multi-grid method. Qualitative and quantitative analyses of the differences between the 2D and 3D simulation results reveal the 3D effect on the flow field characteristics and hydrodynamic coefficients of the vertically oscillating cylinder with a bottom-attached disk. The 3D effect on the fluid field is mainly reflected in the significance of three vortex-shedding patterns: ω_x has a greater effect on the flow fields around the sharp edges relative to the vortices generated in the 2D simulation. In the slice along the axial orientation, the vortex effect of ω_y along the radial axis is smaller than that of ω_x along the circumferential direction, indicating the radial effect on the velocity more pronounced than the circumferential effect around the sharp edges of the disk. The rotational interaction ω_z of the fluid in the horizontal plane during the heave motion is insignificant. Based on the 2D and 3D simulation results, the turning points that separate the increasing regimes of the added mass coefficient and damping ratio are identified. The dependence of the turning point on the diameter ratio D_d/D_c and thickness ratio t_d/D_c are discussed in detail.     

Thermal entanglement in two-qutrit spin-1 anisotropic Heisenberg model with inhomogeneous magnetic field

The thermal entanglement of a two-qutrit spin-1 anisotropic Heisenberg XXZ chain in an inhomogeneous magnetic field is studied in detail. The effects of the external magnetic field (B), a parameter b which controls the inhomogeneity of B, and the bilinear interaction parameters J_x=Jy≠Jz on the thermal variation of the negativity are studied in detail. It is found that negativity N decreases when the values of magnetic field, inhomogeneity b and temperature are increasing. In addition, N remains at higher temperatures for higher values of J_z and lower values of B and b.     

Ultimate Lateral Capacity of Rigid Pile in c-φ Soil

To date no analytical solution of the pile ultimate lateral capacity for the general c-φ soil has been obtained. In the present study, a new dimensionless embedded ratio was proposed and the analytical solutions of ultimate lateral capacity and rotation center of rigid pile in c-φ soils were obtained. The results showed that both the dimensionless ultimate lateral capacity and dimensionless rotation center were the univariate functions of the embedded ratio. Also, the ultimate lateral capacity in the c-φ soil was the combination of the ultimate lateral capacity (f_c) in the clay, and the ultimate lateral capacity (f_φ) in the sand. Therefore, the Broms chart for clay, solution for clay (φ=0) put forward by Poulos and Davis, solution for sand (c=0) obtained by Petrasovits and Awad, and Kondner''s ultimate bending moment were all proven to be the special cases of the general solution in the present study. A comparison of the field and laboratory tests in 93 cases showed that the average ratios of the theoretical values to the experimental value ranged from 0.85 to 1.15. Also, the theoretical values displayed a good agreement with the test values.     

Thermal activation of current in an inhomogeneous Schottky diode with a Gaussian distribution of barrier height

This paper investigates the thermal activation behaviour of current in an inhomogeneous Schottky diode with a Gaussian distribution of barrier height by numerical simulation. The analytical Gaussian distribution model predicted that the I--V--T curves may intersect with the possibility of the negative thermal activation of current, but may be contradictory to the thermionic emission mechanism in a Schottky diode. It shows that the cause of the unphysical phenomenon is related to the incorrect calculation of current across very low barriers. It proposes that junction voltage V_j, excluding the voltage drop across series resistance from the external bias, is a crucial parameter for correct calculation of the current across very low barriers. For correctly employing the thermionic emission model, V_j needs to be smaller than the barrier height Ф. With proper scheme of series resistance connection where the condition of V_j > Ф is guaranteed, I--V--T curves of an inhomogeneous Schottky diode with a Gaussian distribution of barrier height have been simulated, which demonstrate normal thermal activation. Although the calculated results exclude the intersecting possibility of I--V--T curves with an assumption of temperature-independent series resistance, it shows that the intersecting is possible when the series resistance has a positive temperature coefficient. Finally, the comparison of our numerical and analytical results indicates that the analytical Gaussian distribution model is valid and accurate in analysing I--V--T curves only for small barrier height inhomogeneity.     

Experimental Investigation on the Hydrodynamic Performance of A Wave Energy Converter

Wave energy is an important type of marine renewable energy. A wave energy converter (WEC) moored with two floating bodies was developed in the present study. To analyze the dynamic performance of the WEC, an experimental device was designed and tested in a tank. The experiment focused on the factors which impact the motion and energy conversion performance of the WEC. Dynamic performance was evaluated by the relative displacements and velocities of the oscillator and carrier which served as the floating bodies of WEC. Four factors were tested, i.e. wave height, wave period, power take-off (PTO) damping, and mass ratio (R_M) of the oscillator and carrier. Experimental results show that these factors greatly affect the energy conversion performance, especially when the wave period matches R_M and PTO damping. According to the results, we conclude that: (a) the maximization of the relative displacements and velocities leads to the maximization of the energy conversion efficiency; (b) the larger the wave height, the higher the energy conversion efficiency will be; (c) the relationships of energy conversion efficiency with wave period, PTO damping, and R_M are nonlinear, but the maximum efficiency is obtained when these three factors are optimally matched. Experimental results demonstrated that the energy conversion efficiency reached the peak at 28.62% when the wave height was 120 mm, wave period was 1.0 s, R_M was 0.21, and the PTO damping was corresponding to the resistance of 100 Ω.     

Matter-wave interference in an axial triple-well optical dipole trap

This paper proposes a scheme of axial triple-well optical dipole trap by employing a simple optical system composed of a circular cosine grating and a lens. Three optical wells separated averagely by ～37 μm were created when illuminating by a YAG laser with power 1 mW. These wells with average trapping depth ～0.5 μK and volume ～74 μm³ are suitable to trap and manipulate an atomic Bose--Einstein condensation (BEC). Due to a controllable grating implemented by a spatial light modulator, an evolution between a triple-well trap and a single-well one is achievable by adjusting the height of potential barrier between adjacent wells. Based on this novel triple-well potentials, the loading and splitting of BEC, as well as the interference between three freely expanding BECs, are also numerically stimulated within the framework of mean-field treatment. By fitting three cosine functions with three Gaussian envelopes to interference fringe, the information of relative phases among three condensates is extracted.     

Wave Interactions with Multiple Semi-Immersed Jarlan-Type Perforated Breakwaters

This study examines wave interactions with multiple semi-immersed Jarlan-type perforated breakwaters. A numerical model based on linear wave theory and an eigenfunction expansion method has been developed to study the hydrodynamic characteristics of breakwaters. The numerical results show a good agreement with previous analytical results and experimental data for limiting cases of double partially immersed impermeable walls and double and triple Jarlan-type breakwaters. The wave transmission coefficient C_T; reflection coefficient C_R, and energy dissipation coefficient C_E coefficients and the horizontal wave force exerted on the front and rear walls are examined. The results show that C_R reaches the maximum value when B/L = 0.46n while it is smallest when B/L=0.46n+0.24 (n=0, 1, 2,...). An economical triple semi-immersed Jarlan-type perforated breakwater can be designed with B/L = 0.25 and C_R and C_T ranging from 0.25 to 0.32 by choosing a relative draft d/h of 0.35 and a permeability parameter of the perforated front walls being 0.5 for an incident wave number kh nearly equal to 2.0. The triple semi-immersed Jarlan-type perforated breakwaters with significantly reduced C_R, will enhance the structure’s wave absorption ability, and lead to smaller wave forces compared with the double one. The proposed model may be used to predict the response of a structure in the preliminary design stage for practical engineering.     

The Air-Sea Exchange of CO2 in the East Sea (Japan Sea)

During CREAMS expeditions, fCO₂ for surface waters was measured continuously along the cruise tracks. The fCO₂ in surface waters in summer varied in the range 320–440 μatm, showing moderate supersaturation with respect to atmospheric CO₂. In winter, however, fCO₂ showed under-saturation of CO₂ in most of the area, while varying in a much wider range from 180 to 520 μatm. Some very high fCO₂ values observed in the northern East Sea (Japan Sea) appeared to be associated with the intensive convection system developed in the area. A gas-exchange model was developed for describing the annual variation of fCO₂ and for estimating the annual flux of CO₂ at the air-sea interface. The model incorporated annual variations in SST, the thickness of the mixed layer, gas exchange associated with wind velocity, biological activity and atmospheric concentration of CO₂. The model shows that the East Sea releases CO₂ into the atmosphere from June to September, and absorbs CO₂ during the rest of the year, from October through May. The net annual CO₂ flux at the air-sea interface was estimated to be 0.032 (±0.012) Gt-C per year from the atmosphere into the East Sea. Water column chemistry shows penetration of CO₂ into the whole water column, supporting a short turnover time for deep waters in the East Sea. This revised version was published online in August 2006 with corrections to the Cover Date.     

Evaluation of ADEOS-II GLI ocean color atmospheric correction using SIMBADA handheld radiometer data

The performance of the “version 2” Global Imager (GLI) standard atmospheric correction algorithm, which includes empirical absorptive aerosol correction and sun glint correction, was evaluated using data collected with handheld above-water SIMBADA radiometers during 23 cruises of opportunity (research vessels, merchant ships), mostly in the North Atlantic and European seas. A number of 100 match-up data sets of GLI-derived and SIMBADA-measured normalized water-leaving radiance (nL _W ) and aerosol optical thickness (AOT) were sorted out, using objective selection criteria, and analyzed. The Root-Mean-Square (RMS) difference between GLI and SIMBADA nL _W was about 0.32 μW/cm²/nm/sr for the 412 nm band, showing improvement by 30% in RMS difference with respect to the conventional “version 1” GLI atmospheric correction algorithm, and the mean difference (or bias) was reduced significantly. For AOT, the RMS difference was 0.1 between GLI estimates and SIMBADA measurements and the bias was small (a few 0.01), but the ?ngstr?m exponent was systematically underestimated, by 0.4 on average, suggesting a potential GLI calibration offset in the near infrared. The nL _W differences were not correlated to AOT, although performance was best in very clear conditions (AOT less than 0.05 in the 865 nm band). Despite the relatively large scatter between estimated and measured nL _W , the derived chlorophyll-a concentration estimates, applying the same ratio algorithm (GLI OC4V4) to GLI and SIMBADA, were consistent and highly correlated in the range of 0.05–2 μg/l. The large variability in chlorophyll-a concentration estimate for clear clean water areas (e.g. with the concentration range lower than about 0.05 μg/l) turns out to be due to the nature of the “band ratio” based in-water algorithm.     

Effects of virus infection on expression of cell cycle regulatory proteins in the unicellular marine algae Emiliania huxleyi

The authors have investigated the biochemical events by which marine algal virus infection induces cell cycle arrest. The key G₂/M-phase regulatory proteins are analyzed by immunobloting in unicellular Emiliania huxleyi, suggesting that virus induced cell cycle arrest is related with virus''s effect on cyclins and cyclin dependent kinases. E. huxleyi virus (EhV) represses Cdc2/cyclinB complex activity by inhibiting the activity of Cdc2 kinase in a phosphorylation-related manner, blocking host cells G₂/M checkpoint. Dephosphorylated/inactive Cdc25C combined with up-regulation of Wee1 expression at early infect period appears to be important mechanisms by which EhV represses Cdc2/cyclinB complex activity that is required for entry into M phase. This study has allowed us to confirm that algal virus infection leads to selective activation or inhibition of certain cell-cycle factors, which may play a significant role in establishing a more efficient environment for viral gene expression and DNA replication.     

The ground-state entanglement in the spin-XX chain with a magnetization current

The ground-state entanglement in a transverse spin-1/2 XX chain with a magnetization current is studied. By introducing a magnetization current to the system, a quantum phase transition to current-carrying phase may be presented with the variation of the driving field λ for the magnetic field h>1; and the ground-state entanglement arises simultaneously at the critical point of quantum phase transition. In our model, the introduction of magnetization current may result in more entanglement between any two nearest-neighbour spins.     

O<Subscript>2</Subscript> consumption rate and its isotopic fractionation factor in the deep water of the Philippine Sea

Concentration and stable isotopic compositions (δ ¹⁸O) of dissolved O₂ were measured in seawater samples collected from the Philippine Sea in June 2006. The in-situ O₂ consumption rate and the isotopic fractionation factor (α _r ) during dissolved O₂ consumption were obtained from field observations by applying a vertical one-dimensional advection diffusion model to the deep water mass of about 1000–4000 m. The average O₂ consumption rate and α _r were, respectively, 0.11 ± 0.07 μmol kg⁻¹yr⁻¹ and 0.990 ± 0.001. These estimated values agree well with values from earlier estimations of Pacific deep water. The in-situ O₂ consumption rates are two or more times higher north of 20°N, although the value of α _r was not significantly different between the north and south. Its levels varied rapidly in the water mass of less about 2000 m depth. These results suggest that organic matter from the continent imparts a meaningful contribution to the upper water in the northern part of the area; it might produce the strong O₂ minimum that is evident in the water mass from about 1000–2000 m in the northern part of the Philippine Sea.     

Experimental Study on Flow past A Rotationally Oscillating Cylinder

A series of experiments was carried out to study the flow behaviour behind a rotationally oscillating cylinder at a low Reynolds number (Re=300) placed in a recirculation water channel. A stepper motor was used to rotate the cylinder clockwise- and- counterclockwise about its longitudinal axis at selected frequencies. The particle image velocimetry (PIV) technique was used to capture the flow field behind a rotationally oscillating cylinder. Instantaneous and time-averaged flow fields such as the vorticity contours, streamline topologies and velocity distributions were analyzed. The effects of four rotation angle and frequency ratios F_r (F_r=f_n/f_v, the ratio of the forcing frequency f_n to the natural vortex shedding frequency f_v) on the wake in the lee of a rotationally oscillating cylinder were also examined. The significant wake modification was observed when the cylinder undergoes clockwise-and-counterclockwise motion with amplitude of π, especially in the range of 0.6≤F_r≤1.0.     

Influence of Turbulence Intensity and Turbulence Length Scale on the Drag, Lift and Heat Transfer of A Circular Cylinder

Influence of the turbulence intensity and turbulence length scale on the hydrodynamic characteristics and heat transfer of a circular cylinder, streamlined by a viscous fluid flow, is numerically studied. We take the Reynolds number of the oncoming flow equal to 4×10⁴, the turbulence intensity Tu_f and the dimensionless turbulence length scale L_f varying from 1.0% to 40% and from 0.25 to 4.0, respectively. We confirmed that the increase of Tu_f leads to the suppression of the periodic vortex shedding from the cylinder surface, and as a result the stationary mode of streamlining is formed. Consequently, with the increasing turbulence intensity directly in front of the cylinder Tu^*, the amplitude of the lift coefficient decreases monotonically. Nevertheless, the time-averaged drag coefficient of the streamlined cylinder decreases at Tu^*<6.0%, and increases at Tu^*>9.0%. The dependence of the average Nusselt number on Tu^* is near-linear, and with the increasing turbulence intensity, the Nusselt number rises. However, the change of the average Nusselt number depending on L_f is non-monotonic and at L_f=1.0, the value reaches its maximum.     

New Relationship for Estimation of Wave Overtopping on Vertical Walls

Soft computing tools in the form of combination of multiple nonlinear regression and M5'' model tree were used for estimation of overtopping rate at the vertical coastal structures. For reliable and precise estimation of overtopping rate, the experimental data available in the database CLASH were used. The dimensionless overtopping rate was estimated in terms of conventional dimensionless parameters including the relative crest freeboard R_c/H_s, seabed slope tanθ, deep water wave steepness S_om, surf similarity ξ_om and local relative water depth h_t/H_s. The accuracy of the new model was compared with other existing models and also evaluated with some field measurements. The results indicated that the model presented in this paper is more accurate than other existing models. With statistical parameters, it is shown that the accuracy of predictions in the new model is better than that of other models.     

Photosynthetic activity and antioxidative response of seagrass Thalassia hemprichii to trace metal stress

This study concerned the accumulation of trace metals in tissues of seagrass (Thalassia hemprichii) exposed to various concentrations of Zn²⁺+, Cd²⁺+, Pb²⁺+ and Cu²⁺+ for 10 d, and the effect of excessive metals on quantum yield (ΔF=F_m'), photosynthetic pigments and antioxidative enzymes like superoxide dismutase (SOD), guaiacol peroxidase (POD) were also examined. Cadmium was the most highly accumulated metal. Meanwhile, high metals levels led to a remarkable breakdown of photosynthetic parameters. Especially, ΔF=F_m', chlorophyll and carotenoid were significantly low during prolonged Cu exposure. Besides, ΔF=F_m' was more severely depressed by Cu and Zn than Pb and Cd. However, T. hemprichii had positive response by increasing the activity of SOD and POD. The results indicate that T. hemprichii is the most sensitive to Cu, and the antioxidative protection mechanisms of T. hemprichii are more efficiently activated to avoid damage of Zn, Cd and Pb stress. Finally, due to the high Cd-accumulation and strong Cd-tolerance capacity, T. hemprichii can be used for phytoremediation in Cd-contaminated areas.     

Retrieval of total ozone in the mesosphere with a new model of electronic-vibrational kinetics of O<Subscript>3</Subscript> and O<Subscript>2</Subscript> photolysis products

The paper presents a new model of electronic-vibrational kinetics of the products of ozone and molecular oxygen photodissociation in the terrestrial middle atmosphere. The model includes 45 excited states of the oxygen molecules O₂(b ¹, Σ _g ⁺ ,v= 0−2), O₂ (a ¹Δ _g , v= 0−5), and O₂(X ³Σ _g ⁻ , v= 1−35) and of the metastable atom O (¹ D) and over 100 aeronomic reactions. The model takes into account the dependence of quantum yields of the production of O₂(a ¹Δ _g , v= 0−5) in a singlet channel of ozone photolysis in the Hartley band on the wavelength of photolytic emission. Taking account of the electronic-vibrational kinetics is important in retrieval of the vertical profiles of ozone concentration from measured intensities of the Atm and IR Atm emissions of the oxygen bands above 65 km and leads to an increase in the ozone concentration retrieved from the 1.27-μm emission, in contrast to the previous model of pure electronic kinetics. Sensitivity analysis of the new model is made for variations in the concentrations of atmospheric constituents ([O₂], [N₂], [O(³P)], [O₃], [CO₂]), the gas temperature, rate constants of the reactions, and quantum yields of the reaction products. A group of reactions that most strongly affect the uncertainty of ozone retrieval from measured intensities of atmospheric emissions of molecular oxygen O₂(b ¹Σ _g ⁺ , v) and O₂(a ¹Δ _g , v) has been determined. Original Russian Text ? V.A. Yankovsky, V.A. Kuleshov, R.O. Manuilova, A.O. Semenov, 2007, published in Izvestiya AN. Fizika Atmosfery i Okeana, 2007, Vol. 43, No. 4, pp. 557–569.