李方实
,
Dieter MARTENS
,
Antonius KETTRUP
色谱
doi:10.3321/j.issn:1000-8713.2001.06.015
建立了固相萃取-高效液相色谱(SPE-HPLC)同时测定水中16种苯脲除草剂的方法.HPLC采用Lichrospher 100 RP-18e柱,紫外检测波长为240 nm,流动相为乙腈水溶液,流速为1 mL/min,采用梯度洗脱方式.HPLC分析时间少于20 min.水中的除草剂用C18柱固相萃取富集1!000倍.在优化的条件下,各成分的添加回收率为87.8%～103.7%.此方法的检测限低于欧盟允许的水中除草剂含量上限的1/10.
关键词:
高效液相色谱
,
固相萃取
,
苯脲除草剂
,
水
郭可信
材料科学与工程学报
doi:10.3969/j.issn.1673-2812.2000.04.001
Widmanstatten在19世纪初用硝酸水溶液腐刻铁陨石切片，观察到片状Fe-Ni奥氏体的规则分布(魏氏组织)，予告金相学即将诞生。Sorby在1863年用反射式显微镜观察抛光腐刻的钢铁试样，不但看到珠光体中的渗碳体和铁素体的片状组织，还对钢的淬火和回火作了初步探讨，金相学已基本形成。到19－20世纪之交，Martens(马氏)和Osmond对金相学的发展和金相检验在厂矿中的推广做了重要贡献，同时Roberts-Austen(奥氏)和Roogzeboom初步绘制出Fe-C平衡图，为金相学奠定了理论基础。到了二十世纪中叶，金相学已逐步发展成金属学、物理冶金和材料科学。
关键词:
金相学
,
历史
,
早期史
M.Krauss
,
B.Scholtes
材料科学技术（英文）
The lifetime of hot-work tools is often limited by the development of thermal shock cracks. To analyze the influence of near-surface materials states on the damage process during thermal shock loading, isothermal annealing experiments and thermal shock tests with hot-work tool steel AISI H11 in hard turned, electroeroded, shot-peened or deep rolled surface conditions were performed. Cyclic thermal shock tests were carried out by heating and subsequent quenching of specimens. Crack depths and crack densities were investigated after 100, 1000, 10000 and 30000 cycles at microsections using optical microscopy. Complementary, residual stresses were determined by X-ray diffraction-(XRD) stress analysis. Under identical thermal loading conditions characteristic cracking behaviour was observed at different surface types examined. Neither deep rolling nor shot-peening results in decreasing crack lengths compared to hard turned surface conditions. While the residual stress state during simple annealing is proportionally stable, almost all initial residual stresses relaxed during a few hundred thermal shock cycles. Additional Martens-hardness measurements and FWHM values of XRD analyses indicate that the work hardening induced by mechanical surface treatment is not stable under thermal shock loading.
关键词:
Thermal shock
,
null
,
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