共查询到20条相似文献,搜索用时 343 毫秒
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Hae Sang Jun Bong Oh Kim Yeon Chul Kim Ho Nam Chang Seong Ihl Woo 《Journal of Polymers and the Environment》1994,2(1):9-18
Copolyesters containing poly(ethylene terephthalate) (PET) and poly(-caprolactone) (PCL) were synthesized from PET and PCL homopolymers by transesterification reaction at 270°C in the presence of catalyst. The copolyesters were characterized by13C-NMR and differential scanning calorimetry (DSC). The degradation behavior of PCL byPseudomonas sp. lipase in buffer solution (pH 7) and tetrahydrofuran (THF) was investigated by gel permeation chromatography (GPC) and1H-NMR. From these experiments, it was found thatPseudomonas sp. lipase acted endoenzymatically on PCL. Using this lipase, degradation tests for PET/PCL copolyesters whose PCL content was below 50% by weight were also performed in buffer solution (pH 7). However, evenPseudomonas sp. lipase with high degradation activity on PCL did not easily degrade the PCL unit in PET/PCL copolyesters. 相似文献
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《Waste management & research》1989,7(3):299-300
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《Waste management & research》1988,6(2):187
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增敏碘量法同时测定微量Mn(Ⅱ)、 Mn(Ⅶ)、 Cr(Ⅲ)、 Cr(Ⅵ) 总被引:1,自引:0,他引:1
介绍了用增敏碘量法同时测定微量的Mn(Ⅱ)、Mn(Ⅶ)、Cr(Ⅲ)和Cr(Ⅵ)。将样品中的Mn(Ⅶ)和Cr(Ⅵ)用Na2SO3预先还原,在pH为3.0的醋酸盐介质中对Mn(Ⅱ)和Cr(Ⅲ)用过量KIO4氧化(当用H2P2O2-7掩蔽Cr(Ⅲ)时,只有Mn(Ⅱ)被氧化),过剩的IO-4用钼酸盐掩蔽,加入KI后,以Na2S2O3滴定游离出的I2。此法对Mn的测定范围为29~14706μg/L,相对标准偏差为0.31%~1.18%;对Cr的测定范围为59~10294μg/L,相对标准偏差为0.36%~1.12%。此法与常规滴定法测定Mn和Cr相比,分别可增敏20倍和12倍 相似文献
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《Waste management & research》1990,8(5):393-394
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《Waste management & research》1989,7(4):387-388
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《Waste management & research》1987,5(4):524-525