No abstract

This paper analyzed the seasonal-temporal variation of Cd in bottom waters in Jiaozhou Bay during [1979][1980][1981][1982][1983]. Results showed that for seasonal variation, Cd contents in bottom waters in spring and summer were relatively low and were confirmed to Grade I, while in autumn were relatively high and the highest values of Cd contents were confirmed to Grade II. For temporal variation, the highest values of Cd contents in bottom waters in 1979-1982 were confirmed to Grade I, while in 1983 were Grade II. This indicated that the input of Cd to the bay was different in different seasons, and the time lag of pollution treatment to the development industry could cause environment pollution and ecological damage.

In recent years, the construction of tunnels and subways has increased significantly. Current researches related to the underground engineering always focus on quasi-static force analysis of semi-infinite media, thus it is of great significance to analysis the borehole pressure during tunnel construction. In this paper, a finite cavity expansion model in finite diameter geological media is proposed considering the influence of finite radial extent of geological media and drilling velocity, and theoretical and computational analysis is carried out.

We analyzed the vertical distributions, seasonal variations and transfer processes of Pb in Jiaozhou Bay based on investigation data in surface and bottom waters in 1986. Results showed that Pb contents in surface waters were in order of spring < autumn < summer. By means of vertical water's effect, Pb was settling from surface waters to bottom waters continuously, and was accumulating in bottom waters continuously, resulting in Pb contents in bottom waters were in order of spring < summer < autumn. The variation ranges of Pb contents in April, July and October in waters in the bay mouth were basically consistent. In case of Pb contents in surface waters were low, accumulation effect was making a role in bottom waters. In case of Pb contents in surface waters were high, dilution effect was making a role in bottom waters. The seasonal variations of Pb contents in surface waters were following to the seasonal variation of the inflow rivers, while the seasonal variations of Pb contents in bottom waters were determining by vertical water's accumulation effect. For spatial scale, Pb contents in surface and bottom waters were tending to be consist, no matter the input of Pb was different in time, source and source strength. In generally, the seasonal variations, variation ranges and horizontal distributions of Pb contents in surface and bottom waters were confirming the vertical settling process that Pb was settling to sea bottom rapidly by means of gravity force and marine current.

In this study, the kinetics of arsenite (As(III)) removal in a ferrihydrite/oxalate system under irradiation was investigated, and the effects of pH, ferrihydrite dosage, As(III) initial concentration, and oxalate concentration...