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851.
秩消因子分析—荧光光度测定某些食物中的营养元素硒 总被引:1,自引:0,他引:1
本文应用秩消因子分析-荧光光度法测定了食物中营养元素硒的含量,与文献〔1〕报道的DAN-荧光光度法测定结果比较,具有良好的统计学一致性,从而为简化实验操作,改善痕量硒测定的准确性和灵敏度提供了新的可能。 相似文献
852.
Miniaturizing all dimensions of apparatus, such as electronics and computers, is the current trend followed by scientists
in various fields. The idea of Lab-on-a-Chip has significantly expanded and found its broad applications in analytical chemistry.
Microplasmas can act as a sample excitation source and are the miniaturized versions of full-sized plasmas. These can be created
in various forms, such as direct current, microwave induced, capacitively coupled and inductively coupled plasmas. Scaling
down the size would reduce the amount of gases, liquids and consumables required, as well as the sample analysis time, which
in turn would decrease the operating costs. Therefore, several research groups are involved in the development of microplasmas
for utilisation in analytical instruments. 相似文献
853.
M. E. Umstead S. A. Lloyd J. W. Fleming M. C. Lin 《Applied physics. B, Lasers and optics》1985,38(4):219-224
The reaction of NO2 with isobutane, induced by 488 nm laser radiation, to form 2-nitro-2-methylpropane has been investigated and the results computer-modeled according to two possible reaction mechanisms. The first scheme involves the direct abstraction of H from isobutane by vibronically excited NO2 (NO
2
*
), and the second, abstraction by an intermediate NO3 radial produced by NO
2
*
+NO2. The modeling results strongly support the NO
2
*
scheme as the dominant reaction mechanism. 相似文献
854.
855.
856.
We have encapsulated several hemoproteins in the sol-gel glass to catalyze the oxidation reaction of dibenzothiophene (model
for organic sulfur compounds in coal) with hydrogen peroxide. In addition to cytochrome c and myoglobin, which have previously
been encapsulated in sol-gel glasses, two other hemoproteins, horseradish peroxidase and bovine blood hemoglobin, have now
been successfully immobilized in sol-gel media with the retention of their spectroscopic properties. All four hemoproteins
studied also demonstrate similar catalytic activities toward the oxidation of dibenzothiophene as compared with the results
obtained with the proteins in solution. In the case of encapsulated cytochrome c, the more water-soluble S-oxide was obtained
with much higher selectivity over the less water-soluble sulfone (S-oxide/sulfone = 7.1) as compared to what was obtained
in the aqueous/organic medium (S-oxide/sulfone = 2.3). Because of the advantage of easy separation of the encapsulated proteins
from the liquid reaction mixture, it is clear from these studies that the immobilization of active hemoproteins in the solid
glass media could serve as more practical biocatalysts. 相似文献
857.
Commercial poly(ethylene terephthalate) (PET) was treated at R. H.>80% and room temperature for a set time. The glass transition
temperature (Tg) decreases with the time of exposure to high humidity. The decrease in Tg is a result of plasticization. Our
data indicate that the Tg of dry PET of 76-78°C may decrease to as low a temperature as 65-67°C when it is wet. Induced crystallization
of PET in the presence of water reduces the cold crystallization temperature (Tc). The structure of water-induced crystals
is imperfect and can be improved in perfection by annealing.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
858.
Hua Lin XIE Yu Jie LI Xi Du NIE Li Bo LI 《中国化学快报》2006,17(7):945-948
Because of its high sensitivity, wide dynamic range and relative freedom from interferences, inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the determination of trace and ultra-trace levels of elements in various fields1. Due… 相似文献
859.
860.