Science China Press., Co. Ltd.

The decrease of the electron density in the d orbits of Ni2 + ions, resulting from the disturbance of micro-environments in which Ni2+ ions are located, makes the frequency of adsorbed NO shlft higher. The shift degree is determined mainly by the property of the microenvironments. When Ni2+ ions are located onSII,SII(SI) sites of Y zeolite or on the surface of γ-alumina, their NO adsorption gives rise to IR bands at 1 905, 1 900 and 1 855–1 875 cm−1, respectively. The distribution of Ni2+ ions on the various micro-environments of USY zeolite, Al2O3 and MS mixed carrier has also been discussed according to the different frequencies of adsorbed NO, as well as the influence of NiO loading.

Drifting buoys, satellite altimetry and satellite-derived sea surface thermal images are used to identify the existence of a large cold-core, cyclonic Kuroshio frontal eddy between Hengchun Peninsula and Lanyu, southeast off Taiwan Island around March 1996. The cold eddy accompanies an offshore meander of the Kuroshio near Lanyu, about 70 km and 100 km in horizontal zonal and meridional scales, respectively. The cold eddy is different from normal Kuroshio frontal eddies for its persisting of about 2 months near Lanyu. Supporting evidence suggests that the Kuroshio intruded into the South China Sea (SCS, hereafter) forming a loop-like structure during the persisting period of the cold eddy and that similar eddies occur occasionally in the same location. Compared with the corresponding studies in the Gulf of Mexico, it is suggested that Lanyu cold eddies are SCS analogues of Tortugas eddies found in the southern Straits of Florida. Overshooting of the meandering Kuroshio when it leaves the SCS and effects from conservation of potential vorticity are the possible mechanism of eddy genesis.

The SIJR model, simplified from the SEIJR model, is adopted to analyze the important parameters of the model of SARS epidemic such as the transmission rate, basic reproductive number. And some important parameters are obtained such as the transmission rate by applying this model to analyzing the situation in Hong Kong, Singapore and Canada at the outbreak of SARS. Then forecast of the transmission of SARS is drawn out here by the adjustment of parameters (such as quarantined rate) in the model. It is obvious that inflexion lies on the crunode of the graph, which indicates the big difference in transmission characteristics between the epidemic under control and not under control. This model can also be used in the comparison of the control effectiveness among different regions. The results from this model match well with the actual data in Hong Kong, Singapore and Canada and as a by-product, the index of the effectiveness of control in the later period can be acquired. It offers some quantitative indexes, which may help the further research in epidemic diseases.

Using the d.c. four-probe method, the electrical resistivity of high-purity liquid Sb has been accurately measured as functions of temperature. It is observed that the resistivity of liquid Sb changes abnormally with increasing temperature, which is very different from that of simple liquid metals. Based on the reported structure factor at several temperatures, the results obtained in this work have been discussed and interpreted qualitatively according to Ziman theory. The analysis suggests that the existence of shortrange order structure near the melting point can account for the abnormal phenomenon observed in the resistivity of liquid Sb, in which semimetal-metal transaction takes place in the melting process. At the same time, the progress of the structure change of liquid Sb with temperature has also been pointed out.

A new screening approach for anticancer active compounds is presented. In this method, a target enzyme is incubated with a mixture of compounds, and then the complex formed by the target and small molecules is separated from the rest of the mixture by ultra-filtration. The complex that is retained on the membrane is subsequently washed with acid and small molecules that are specifically bound to the target are released and collected, then analyzed by highperformance liquid Chromatograph combined with electrospray ionization mass spectrometry (HPLC/ESI-MS) analysis. We have successfully applied this method to screen anticancer compounds. DNA topoisomerase II is used as a target to capture anti-tumor candidates from a mixture of combinatorial compounds, such as doxorubicin, daunorubicin and pravastain.

A sediment core was collected from the Fildes Peninsula of Antarctica, which contained numerous seal hairs and was identified to be seal excrement deposition. By analyzing its total organic carbon (TOC) and concentrations of bio-elements, the seal population changes of the past century were reconstructed. The variation of seal population in the last century on the Fildes Peninsula is primarily controlled by human activities. The sealing industry in the early 20th century caused the dramatic decline of seal population. The protection of the Antarctic seals since the 1960s and the reduced seal’s competition with whales for prey resources due to whaling lead to the recovery of seal population and make the high level of the seal population sustainable.