• Transactions of Materials Processing
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• v.3 no.3
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• pp.320-334
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• 1994

A set of full size cold rolled steel sheets has been prestrained in the direction of rolling by uniform tensile elongation of 3% and 6%. Then mid-sized tensile specimens were cut from each of the full size sheets at 30, 45, 60 and 90 degrees to the rolling direction. The mid-sized tensile specimens were then prestrained again by uniform tensile elongation by 1%, 2%, 5%, 10% and 15%. finally, miniature tensile specimens were prepared from each of the mid-sized specimens at every 10 degrees to the specimen axis. From the tensile tests on miniature specimens material's hardening behavior under non-proportional loading has been investigated. There are a number of new observations which has not been known to the authors before current work. One of them is continuous reservation of orthoropic symmetry during tensile elongation of mid-sized specimens. Another is continuous rotations of orthotropy axes. Existing theories seem to fail to explain this observations. A new model is proposed in relation to the rotation of orthotropy axes.

• Korean journal of applied entomology
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• v.42 no.3
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• pp.241-248
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• 2003

The aphid-eating gall-midge, Aphidoletes aphidimyza (Rondani), as predator of aphids was wildly used as one of the biological control agents for control of several kinds of aphids. Their some kinds of biological characteristics were examined. The developmental periods of A. aphidimyza from egg to adult with the green peach aphid as prey were 40 and 12 days at 15$^{\circ}C$ and 30$^{\circ}C$, respectively. Supplying the cotton aphid as prey, their developmental periods were shorter than with the green peach aphid. In case of the preservation of pupa in the cold condition, emergence rates were over 90% for 1 and 2 weeks at 5$^{\circ}C$ and l0$^{\circ}C$, respectively. Adult females of A. aphidimyza began mating and laying eggs at 2-3 days after emergence, and they laid about 200 eggs for lo days of average life span. Most of adults were emerged from pupa at 6 to 8 pm during a day, and they mainly acted in the early night.