ABSTRACT
In this paper, the effects of an aging treatment on the corrosion resistance/mechanism of a tensile deformed Al-Cu-Mn-Fe-Zr alloy are investigated. The impedance magnitude and polarization resistance increase, while the corrosion current decreases with the increased aging time and temperature. The discontinuously-distributed precipitates and precipitation-free zone, which can cut the corrosion channels, appear at grain boundaries when the temperature is relatively high and the aging time is relatively long. They can improve the corrosion resistance. Additionally, the intergranular and pitting corrosion are the main mechanisms. The intergranular corrosion is likely to occur in an under-aged alloy. This is because the potential difference between the grain boundaries and grains is high, due to the segregation of Cu atoms. When the aging degree is increased, the grain boundary precipitates reduce the potential difference, and the intragranular precipitates make the surrounding matrix prone to dissolution. As such, the pitting corrosion is likely to occur in the over-aged alloys.
ABSTRACT
OBJECTIVE: To study the chemical constituents of Phlomis younghusbandii. METHODS: Column chromatography was used in the isolation procedure. The structures of isolated compounds were elucidated by spectral data RESULTS: Eight compounds were isolated and their structures were identified as barlerin (1), sesamoside (2), phloyoside II (3), salidroside (4), shanzhiside methyl ester (5), acteoside (6), luteolin-7-O-glucoside (7), daucosterol (8). CONCLUSION: Compound 4 is firstly isolated from Phlomis genus. Compound 4 and 6 are obtained from this plant for the first time.
Subject(s)
Glucosides/isolation & purification , Iridoids/isolation & purification , Phenols/isolation & purification , Phlomis/chemistry , Plants, Medicinal/chemistry , Flavones/chemistry , Flavones/isolation & purification , Glucosides/chemistry , Iridoids/chemistry , Magnetic Resonance Spectroscopy , Molecular Structure , Phenols/chemistry , Plant Roots/chemistry , Pyrans/chemistry , Pyrans/isolation & purificationABSTRACT
The newest development of applications of IR techniques to the identification of Chinese herbs, the discrimination of folk medicine herbs, Chinese herbs processing and Chinese traditional injection, which involving enhancing computer analysis depth, intensifying the pre-treatment of Chinese herb and using 2D-IR correlation spectroscopy for processing control, was elaborated in the present paper. Meanwhile, the establishment of multi-component determination analysis system of chromatographic fingerprint diagram was shown. And the sameness and difference of the IR spectroscopy and chromatography fingerprint diagram techniques were analyzed, and a comparison was made in terms of quality control of Chinese herbal medicine.
