Partial oxidation of methane to synthesize gas over Ni/alpha-Al2O3 catalyst promoted by noble metals

The production of synthesis gas by partial oxidation bf methane in oxygen has been examined over Ni/alpha-Al2O3 catalyst promoted by noble metals(Rh, Ru, Pt and Pd), especially with Pt. The reactivity is considered in conjunction with the result of H-2-TPR, CO-TPD, SEM and XRD. It is found that small amount of Pt results in a great improvement of activity for the Ni/alpha-Al2O3 catalyst. The activity order is : Rh-Ni>Pt-Ni approximate to Ru-Ni>Pd-Ni, meantime the Pt improves the stability of Ni/alpha-Al2O3 catalyst except for Pd which is easy to he deactivated by carbon deposition. The results of TPD, SEM and XRD indicate that there is an interaction between Ni and Pt metals in the catalyst. The interaction increases the dispersions of Pt and Nit the presence of Pt suppresses the growth and the migration of Ni grains over the surface of the catalyst.

Cloning and sequence analysis of the partial sequence of the rbcL from Bryopsis hypnoides

The partial sequence of the rbcL from Bryopsis hypnoides, including the sequences of the upstream, extron and partial intron, was amplified by PCR and their sequences were determined. With Spinacia oleracea as the outgroup, neighbor-joining method and maximum parsimony method were used respectively to build phylogenetic trees according to the rbcL exon sequence among 13 species that were the typical species of six phyla. Two kinds of trees showed clearly that there were two groups among those species, the green lineage and the non-green lineage. And the relationships of algae in the green lineage were similar in the two trees but those in the non-green lineage were not consistent. Analysis of codon preference indicated that the codon preference of the rbcL exon of Bryopsis hypnoides distinctly differed from that of the relevant sequence of photosynthetic bacteria.

Purification and partial characterization of Mn superoxide dismutase from muscle tissue of the shrimp Macrobrachium nipponense

Superoxide dismutase (SOD; EC 1.15.1.1) is an enzyme that protects against oxidative stress from superoxide radicals in living cells. This enzyme had been isolated, purified and partially characterized from muscle tissue of the shrimp Macrobrachium nipponense. The purification was achieved by heat treatment, ammonium sulfate fractionated precipitation and column chromatograph on DEAE-cellulose 32. Some physiological and biochemical characterization of it was tested. The molecular weight of it was about 21.7 kDa, as judged by SDS-polyacrylamide gel electrophoresis. The purified enzyme had an absorption peak of 278 nm in ultraviolet region, and the enzyme remained stable at 25-45 degreesC within 90 min. However, it was rapidly inactivated at higher temperature. Treatment of the enzyme with 1 mM ZnCl2, SDS and 1 mM or 10 mM mercaptoethanol showed some increasing activity. However, the enzyme activity was obviously inhibited by 10 mM CaCl2, CuSO4, ZnCl2 and 1 mM CaCl2 and 10 mM K2Cr2O7. SOD activity did not show significantly variation after incubated with 1 mM CaCl2, EDTA and 10 MM SDS. The enzyme was insensitive to cyanide and contained 1.03 +/- 0.14 atoms of manganese per subunit shown in atomic absorption spectroscopy, which revealed that purified SOD was Mn superoxide dismutase. (C) 2004 Elsevier B.V. All rights reserved.

The complete amino acid sequence of growth hormone and partial amino acid sequence of prolactin and somatolactin from sea perch (Lateolabrax japonicus)

Growth hormone (GH), prolactin (PRL) and somatolactin (SL) were purified simultaneously under alkaline condition (pH 9.0) from pituitary glands of sea perch (Lateolabrax japonicas) by a two-step procedure involving gel filtration on Sephadex G-100 and reverse-phase high-performance liquid chromatography (rpHPLC). At each step of purification, fractions were monitored by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and by immunoblotting with chum salmon GH. PRL and SL antisera. The yields of sea perch GH, PRL and SL were 4.2, 1.0 and 0.28 mg/g wet tissue, respectively. The molecular weights of 19,200 and 20,370 Da were estimated by SDS-PAGE for sea perch GH and PRL, respectively. Two forms of sea perch SL were found: one (28,400 Da) is probably glycosylated, while the other one (23,200 Da) is believed to be deglycosylated. GH bioactivity was examined by an in vivo assay. Intraperitoneal injection of sea perch GH at a dose of 0.01 and 0.1 mug/g body weight at 7-day intervals resulted in a significant increase in body weight and length of juvenile rainbow trout. The complete sea-perch GH amino acid sequence of 187 residues was determined by sequencing fragments cleaved by chemicals and enzymes. Alignment of sea-perch GH with those of other fish GHs revealed that sea-perch GH is most similar to advanced marine fish, such as tuna, gilthead sea bream, yellowfin porgy, red sea bream, bonito and yellow tail with 98.4, 96.2%, 95.7%, 95.2%, 94.1% and 91% sequence identity, respectively. Sea-perch GH has low identity to Atlantic cod (76.5%), hardtail (73.3%), flounder (68.4%), chum salmon (66.3%), carp (54%) and blue shark (38%). Partial amino-acid sequences of 127 of sea-perch PRL and the N-terminal of 16 amino-acid sequence of sea-perch SL have been determined. The data show that sea-perch PRL has a slightly higher sequence identity with tilapia PRL( 73.2%) than with chum salmon PRL(70%) in this 127 amino-acid sequence. (C) 2001 Elsevier Science B.V. All rights reserved.

Observation and theoretical analysis for the sand-waves migration in the North Gulf of South China Sea

According to the environmental characteristic of the north gulf of South China Sea, a quasi-3D mechanics model has been built for simulating the small scale sand-waves migration in the seas of southwest of Hainan Island. Based on the submarine micro-geomorphic data induced by multi-beam system and hydrographic survey record, the migrations of the sand-waves in the study area are predicted. The results show that calculation is consistent with the observation data in the groove of sand ridge, but not well in the crest of sand ridge. It is indicated that the mechanics model should be used to predict the migration of the small scale sand-waves which are dominated by bed load in the seas. This paper is very meaningful to project the route of submarine pipeline.

Temperature phase tilt in unstable baroclinic waves

A general property on the phase relation in linear baroclinic instability is proved analytically: in a potential vorticity homogenization regime, the complex geometry of the quasigeostrophic equations determines that the phase lines of temperature and pressure disturbances tilt with height in opposite directions.

A unified criterion for initiation of sediment motion and inception of sheet flow under water waves

A unified criterion is developed for initiation of non-cohesive sediment motion and inception of sheet flow under water waves over a horizontal bed of sediment based on presently available experimental data. The unified threshold criterion is of the single form, U-o = 2 pi C[1 + 5(T-R/T)(2)](-1/4), where U-o is the onset velocity of sediment motion or sheet flow, T is wave period, and C and T-R are the coefficients. It is found that for a given sediment, U-o initially increases sharply with wave period, then gradually approaches the maximum onset velocity U-o = 2 pi C and becomes independent of T when T is larger. The unified criterion can also be extended to define sediment initial motion and sheet flow under irregular waves provided the significant wave orbital velocity and period of irregular waves are introduced in this unified criterion.

Remote sensing of ocean waves by along-track interferometric synthetic aperture radar

A new wave retrieval method for the Along-Track Interferometric Synthetic Aperture Radar (AT-InSAR) phase image is presented. The new algorithm, named parametric retrieval algorithm (PRA), uses the full nonlinear mapping relations. It differs from previous retrieval algorithms in that it does not require a priori information about the sea state or the wind vector from scatterometer data. Instead, it combines the observed AT-InSAR phase spectrum and assumed wind vector to estimate the wind sea spectrum. The method has been validated using several C-band and X-band HH-polarized AT-InSAR observations collocated with spectral buoy measurements. In this paper, X-band and C-band HH-polarized AT-InSAR phase images of ocean waves are first used to study AT-InSAR wave imaging fidelity. The resulting phase spectra are quantitatively compared with forward-mapped in situ directional wave spectra collocated with the AT-InSAR observations. Subsequently, we combine the parametric retrieval algorithm (PRA) with X-band and C-band HH-polarized AT-InSAR phase images to retrieve ocean wave spectra. The results show that the ocean wavelengths, wave directions, and significant wave heights estimated from the retrieved ocean wave spectra are in agreement with the buoy measurements.

Validation of RADARSAT-2 fully polarimetric SAR measurements of ocean surface waves

C band RADARSAT-2 fully polarimetric (fine quad-polarization mode, HH+VV+HV+VH) synthetic aperture radar (SAR) images are used to validate ocean surface waves measurements using the polarimetric SAR wave retrieval algorithm, without estimating the complex hydrodynamic modulation transfer function, even under large radar incidence angles. The linearly polarized radar backscatter cross sections (RBCS) are first calculated with the copolarization (HH, VV) and cross-polarization (HV, VH) RBCS and the polarization orientation angle. Subsequently, in the azimuth direction, the vertically and linearly polarized RBCS are used to measure the wave slopes. In the range direction, we combine horizontally and vertically polarized RBCS to estimate wave slopes. Taken together, wave slope spectra can be derived using estimated wave slopes in azimuth and range directions. Wave parameters extracted from the resultant wave slope spectra are validated with colocated National Data Buoy Center (NDBC) buoy measurements (wave periods, wavelengths, wave directions, and significant wave heights) and are shown to be in good agreement.

Third-order Stokes wave solutions for interfacial internal waves in a three-layer density-stratified fluid

Interfacial internal waves in a three-layer density-stratified fluid are investigated using a singular method, and third-order asymptotic solutions of the velocity potentials and third-order Stokes wave solutions of the associated elevations of the interfacial waves are presented based on the small amplitude wave theory. as expected, the third-order solutions describe the third-order nonlinear modification and the third-order nonlinear interactions between the interfacial waves. The wave velocity depends on not only the wave number and the depth of each layer but also on the wave amplitude.

Determination of fractional energy loss of waves in nearshore waters using an improved high-order Boussinesq-type model

Fractional energy losses of waves due to wave breaking when passing over a submerged bar are studied systematically using a modified numerical code that is based on the high-order Boussinesq-type equations. The model is first tested by the additional experimental data, and the model's capability of simulating the wave transformation over both gentle slope and steep slope is demonstrated. Then, the model's breaking index is replaced and tested. The new breaking index, which is optimized from the several breaking indices, is not sensitive to the spatial grid length and includes the bottom slopes. Numerical tests show that the modified model with the new breaking index is more stable and efficient for the shallow-water wave breaking. Finally, the modified model is used to study the fractional energy losses for the regular waves propagating and breaking over a submerged bar. Our results have revealed that how the nonlinearity and the dispersion of the incident waves as well as the dimensionless bar height (normalized by water depth) dominate the fractional energy losses. It is also found that the bar slope (limited to gentle slopes that less than 1:10) and the dimensionless bar length (normalized by incident wave length) have negligible effects on the fractional energy losses.

Generation of internal and surface waves by seafloor movement in a two layer fluid system

Internal and surface waves generated by the deformations of the solid bed in a two layer fluid system of infinite lateral extent and uniform depth are investigated. An integral solution is developed for an arbitrary bed displacement on the basis of a linear approximation of the complete description of wave motion using a transform method (Laplace in time and Fourier in space) analogous to that used to study the generation of tsunamis by many researchers. The theoretical solutions are presented for three interesting specific deformations of the seafloor; the spatial variation of each seafloor displacement consists of a block section of the seafloor moving vertically either up or down while the time-displacement history of the block section is varied. The generation process and the profiles of the internal and surface waves for the case of the exponential bed movement are numerically illustrated, and the effects of the deformation parameters, densities and depths of the two layers on the solutions are discussed. As expected, the solutions derived from the present work include as special cases that obtained by Kervella et al. [Theor Comput Fluid Dyn 21:245-269, 2007] for tsunamis cased by an instantaneous seabed deformation and those presented by Hammack [J Fluid Mech 60:769-799, 1973] for the exponential and the half-sine bed displacements when the density of the upper fluid is taken as zero.

The effects of random surface waves on the steady Ekman current solutions

The response of near-surface current profiles to wind and random surface waves are studied based on the approach of Jenkins [1989. The use of a wave prediction model for driving a near surface current model. Dtsch. Hydrogr. Z. 42,134-149] and Tang et al. [2007. Observation and modeling of surface currents on the Grand Banks: a study of the wave effects on surface currents. J. Geophys. Res. 112, C10025, doi:10.1029/2006JC004028]. Analytic steady solutions are presented for wave-modified Ekman equations resulting from Stokes drift, wind input and wave dissipation for a depth-independent constant eddy viscosity coefficient and one that varies linearly with depth. The parameters involved in the solutions can be determined by the two-dimensional wavenumber spectrum of ocean waves, wind speed, the Coriolis parameter and the densities of air and water, and the solutions reduce to those of Lewis and Belcher [2004. Time-dependent, coupled, Ekman boundary layer solutions incorporating Stokes drift. Dyn. Atmos. Oceans. 37, 313-351] when only the effects of Stokes drift are included. As illustrative examples, for a fully developed wind-generated sea with different wind speeds, wave-modified current profiles are calculated and compared with the classical Ekman theory and Lewis and Belcher's [2004. Time-dependent, coupled, Ekman boundary layer solutions incorporating Stokes drift. Dyn. Atmos. Oceans 37, 313-351] modification by using the Donelan and Pierson [1987. Radar scattering and equilibrium ranges in wind-generated waves with application to scatterometry. J. Geophys. Res. 92, 4971-5029] wavenumber spectrum, the WAM wave model formulation for wind input energy to waves, and wave energy dissipation converted to currents. Illustrative examples for a fully developed sea and the comparisons between observations and the theoretical predictions demonstrate that the effects of the random surface waves on the classical Ekman current are important, as they change qualitatively the nature of the Ekman layer. But the effects of the wind input and wave dissipation on surface current are small, relative to the impact of the Stokes drift. (C) 2008 Elsevier Ltd. All rights reserved.

Self-organized Criticality Model for Ocean Internal Waves

In this paper, we present a simple spring-block model for ocean internal waves based on the self-organized criticality (SOC). The oscillations of the water blocks in the model display power-law behavior with an exponent of -2 in the frequency domain, which is similar to the current and sea water temperature spectra in the actual ocean and the universal Garrett and Munk deep ocean internal wave model [Geophysical Fluid Dynamics 2(1972) 225; J. Geophys. REs. 80 (1975) 291]. The influence of the ratio of the driving force to the spring coefficient to SOC behaviors in the model is also discussed.

Higher-order Boussinesq-type equations for interfacial waves in a two-fluid system

Interfacial waves propagating along the interface between a three-dimensional two-fluid system with a rigid upper boundary and an uneven bottom are considered. There is a light fluid layer overlying a heavier one in the system, and a small density difference exists between the two layers. A set of higher-order Boussinesq-type equations in terms of the depth-averaged velocities accounting for stronger nonlinearity are derived. When the small parameter measuring frequency dispersion keeping up to lower-order and full nonlinearity are considered, the equations include the Choi and Camassa's results (1999). The enhanced equations in terms of the depth-averaged velocities are obtained by applying the enhancement technique introduced by Madsen et al. (1991) and Schaffer and Madsen (1995a). It is noted that the equations derived from the present study include, as special cases, those obtained by Madsen and Schaffer (1998). By comparison with the dispersion relation of the linear Stokes waves, we found that the dispersion relation is more improved than Choi and Camassa's (1999) results, and the applicable scope of water depth is deeper.