Hydrophobic effects on photophysical and photochemical processes——Ⅵ.Character of aggregates formed by hydrocarbon with long chain in poor solvents

Dodecyl β-naphthoate and 3-octadecyl pyrene were used as fluorescence probes for estimation of microscopic polarity in aggregates formed by long chain hydrocarbon C_n(n=10,12, 14,16,18)in dimethyl sulfoxide-water mixed solvent.The polarity in the aggregates is similar to that in cyclohexane.The average aggregation number(N)was determined by using time resolved fluorescence technique.N is dependent on substrate chain length and varies from 15 to 30.The microviscosity was also measured by fluorescence depolarization method.Above phase transition temperature,the microviscosity in aggregates is slightly larger than that in micelle,but below this temperature,the microviscosity in aggregates is as large as that in solid phase.

Effect of Exogenous Lanthanum on Accumulation of Cadmium and Its Chemical Form in Tomatoes

In the condition that soil is polluted by Cd（20 mg·L-1）,two varieties of tomato（Lycopersicon esculintum Mill.）（plant high Cd-enriched variety（Yufen109）and plant low Cd-enriched variety（4641））treated with LaCl3 of different concentration（0,10 and 20mg·L-1）were determined for their effect on plant dry weight,anti-oxidase activity（CAT,SOD and POD）,tomato fruit Cd chemical form and Cd accumulation.The results show that 10 mg？L-1LaCl3 can increase dry weight of plant at various positions and can reduce the concentration of Cd of different forms.Spraying with LaCl3（10,20 mg·L-1）can reduce Cd concentration in leaves,stems,roots and fruits of tomato plants with lowering rates of 13.7%-31.9%,9.5%-30.6%,10.8%-44.5%and 19.4%-37.0%,respectively.Suitable amount of lanthanum（10 mg·L-1 LaCl3）can increase yield of tomatoes,reduce Cd accumulation in the fruit.In the two tomato varieties,Lanthanum and Cadmium react interactively,expressing to be coexisting of both synergism and antagonistic.

Process Design for Hybrid Sheet Metal Components

The global trends towards improving fuel efficiency and reducing CO;emissions are the key drivers for lightweight solutions. In sheet metal processing, this can be achieved by the use of materials with a supreme strength-toweight and stiffness-to-weight ratio. Besides monolithic materials such as high-strength or light metals, in particular metal–plastic composite sheets are able to provide outstanding mechanical properties. Thus, the adaption of conventional, wellestablished forming methods for the processing of hybrid sheet metals is a current challenge for the sheet metal working industry. In this work, the planning phase for a conventional sheet metal forming process is studied aiming at the forming of metal–plastic composite sheets. The single process steps like material characterization, FE analysis, tool design and development of robust process parameters are studied in detail and adapted to the specific properties of metal–plastic composites. In material characterization, the model of the hybrid laminate needs to represent not only the mechanical properties of the individual combined materials, but also needs to reflect the behaviour of the interface zone between them.Based on experience, there is a strong dependency on temperature as well as strain rate. While monolithic materials show a moderate anisotropic behaviour, loads on laminates in different directions generate different strain states and completely different failure modes. During the FE analysis, thermo-mechanic and thermo-dynamic effects influence the temperature distribution within tool and work pieces and subsequently the forming behaviour. During try out and production phase,those additional influencing factors are limiting the process window even more and therefore need to be considered for the design of a robust forming process. A roadmap for sheet metal forming adjusted to metal–plastic composites is presented in this paper.