Analysis of the sea-level variability along the Chinese coast and estimation of the impact of a CO2-perturbed atmospheric circulation

The relationship between monthly sea-level data measured at stations located along the Chinese coast and concurrent large-scale atmospheric forcing in the period 1960-1990 is examined. It is found that sea-level varies quite coherently along the whole coast, despite the geographical extension of the station set. A canonical correlation analysis between sea-level and sea-level pressure (SLP) indicates that a great part of the sea-level variability can be explained by the action of the wind stress on the ocean surface. The relationship between sea-level and sea-level pressure is analyzed separately for the summer and winter half-years. In winter, one factor affecting sea-level variability at all stations is the SLP contrast between the continent and the Pacific Ocean, hence the intensity of the winter Monsoon circulation. Another factor that affects coherently all stations is the intensity of the zonal circulation at mid-latitudes. In the summer half year, on the other hand, the influence of SLP on sea-level is spatially less coherent: the stations in the Yellow Sea are affected by a more localized circulation anomaly pattern, whereas the rest of the stations is more directly connected to the intensity of the zonal circulation. Based on this analysis, statistical models (different for summer and winter) to hindcast coastal sealevel anomalies from the large-scale SLP field are formulated. These models have been tested by fitting their internal parameters in a test period and reproducing reasonably the sea-level evolution in an independent period. These statistical models are also used to estimate the contribution of the changes of the atmospheric circulation on sea-level along the Chinese coast in an altered climate. For this purpose the ouput of 150 year-long experiment with the coupled ocean-atmosphere model ECHAM1-LSG has been analyzed, in which the atmospheric concentration of greenhouse gases was continuously increased from 1940 until 2090, according to the Scenario A projection of the Intergovermental Panel on Climate Change. In this experiment the meridional (zonal) circulation relevant for sea-level tends to become weaker (stronger) in the winter half year and stronger (weaker) in summer. The estimated contribution of this atmospheric circulation changes to coastal sea-level is of the order of a few centimeters at the end of the integration, being in winter negative in the Yellow Sea and positive in the China Sea with opposite signs in the summer half-year.

Synthesis and evaluation of a thiourea-modified chitosan derivative applied for adsorption of Hg(II) from synthetic wastewater

In this work, a thiourea-modified chitosan derivative (TMCD) was synthesized through two steps, O-carboxymethylated first and then modified by a polymeric Schiff's base of thiourea/glutaraldehyde. The adsorption behavior of mercury (II) ions onto TMCD was investigated through batch method. The maximum adsorption capacity for Hg(II) was found to be 6.29 mmol/g at pH 5.0 and both kinetic and thermodynamic parameters of the adsorption process were obtained. The results indicated that adsorption process was spontaneous exothermic reaction and kinetically followed pseudo-second-order model. The adsorption experiments also demonstrated TMCD had high adsorption selectivity towards Hg(II) ions when coexisted with Cu(II), Zn(II), Cd(II) and Ca(II) in solution and it could be easily regenerated and efficiently reused. (C) 2010 Elsevier B.V. All rights reserved.

Combined single-pass conversion of methane via oxidative coupling and dehydro-aromatization

A single-pass process with the combination of oxidative coupling (OCM) and dehydro-aromatization (MDA) for the direct conversion of methane is carried out. With the assistance of the OCM reaction over the SrO-La2O3/CaO catalyst loaded on top of the catalyst bed, the duration of the dehydro-aromatization reaction catalyzed by a 6Mo/HMCM-49 catalyst shows a significant improvement, and. the initial deactivation rate constant of the overall process revealed about 1.5 x 10(-6) s(-1). Up to 72 h on stream, the yield of aromatics was still maintained at 5.0% with a methane conversion of 9.6%, which is obviously higher than that reported for the conventional MDA process with single catalyst. Upon the TPR results, this wonderful enhancement would be attributed to an in-situ formation of CO2 and H2O through the OCM reaction, which serves as a scavenger for actively removing the coke formed during the MDA reaction via a reverse Boudouard reaction and the water gas reaction as well.

Integration of ion-exchange chromatography fractionation with reversed-phase liquid chromatography-atmospheric pressure chemical ionization mass spectrometer and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for isolation and identification of compounds in Psoralea corylifolia

An approach for the separation and identification of components in a traditional Chinese medicine Psoralea corylifolia was developed. Ion-exchange chromatography (IEC) was applied for the fractionation of P corylifolia extract, and then followed by concentration of all the fractions with rotary vacuum evaporator. Each of the enriched fractions was then further separated on an ODS column with detection of UV absorbance and atmospheric pressure chemical ionization mass spectrometer (APCI/MS), respectively, and also analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) with matrix of oxidized carbon nanotubes. Totally more than 188 components in P. corylifolia extract were detected with this integrated approach, and 12 of them were preliminary identified according to their UV spectra and mass spectra performed by APCI/MS and MALDI-TOF/MS. The obtained analytical results not only demonstrated the powerful resolution of integration IEC fractionation with reversed-phase liquid chromatography (RPLC)-APCI/MS and MALDI-TOF/MS for analysis of compounds in a complex sample, but also exhibited the superiority of APCI/MS and MALDI-TOF/MS for identification of low-mass compounds, such as for study of traditional Chinese medicines (TCMs) and metabolome. (c) 2005 Published by Elsevier B.V.

Separation and detection of compounds in Honeysuckle by integration of ion-exchange chromatography fractionation with reversed-phase liquid chromatography-atmospheric pressure chemical ionization mass spectrometer and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis

A hyphenated method for the isolation and identification of components in a traditional Chinese medicine of Honeysuckle was developed. Ion-exchange chromatography (IEC) was chosen for the fractionation of Honeysuckle extract, and then followed by concentration of all the fractions with rotary vacuum evaporator. Each of the enriched fractions was then further analyzed by reversed-phase liquid chromatography-atmospheric pressure chemical ionization mass spectrometer (RPLC-APCI/MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) with matrix of oxidized carbon nanotubes, respectively. It can be noted totally more than 117 components were detected by UV detector, APCI/MS and MALDI-TOF/MS in Honeysuckle extract except the, 145 components identified by MALDI-TOF/MS alone with this integrated approach, and 7 of them were preliminary identified according to their UV spectra and mass spectra performed by APCI/MS and MALDI-TOF/MS, respectively. The obtained analytical results not only indicated the approach of integration IEC fractionation with RPLC-APCI/MS and MALDI-TOF/MS is capable of analyzing complex samples, but also exhibited the potential power of the mass spectrometer in detection of low-mass compounds, such as traditional Chinese medicines (TCMs) and complex biological samples. (c) 2005 Elsevier B.V. All rights reserved.