Aim To investigate the chemical constituents of Piper wallichii. Methods Five compounds were isolated by silica gel column chromatography and Sephadex LH-20 gel column chromatography, and the structures of compounds w...Aim To investigate the chemical constituents of Piper wallichii. Methods Five compounds were isolated by silica gel column chromatography and Sephadex LH-20 gel column chromatography, and the structures of compounds were identified by spectral analysis. Result Five compounds were identified as piperlonguminine （trans, trans） （1）, 4-hydroxy-3,5-dimethoxy-benzoic acid （2）, galgravin （3）, β-sitosterol （4）, and daucosterol （5）. Conclusion Five compounds were isolated from Piper wallichii for the first time, and compounds 1 -3 were isolated from this genus far the first time.展开更多
To research the loading charactefistc of rocks with different structures cut by helical cutting mechanism （HCM）, three different structures of rock （hard-soft-hard rock, soft-hard rock and soft-hard-soft rock） wer...To research the loading charactefistc of rocks with different structures cut by helical cutting mechanism （HCM）, three different structures of rock （hard-soft-hard rock, soft-hard rock and soft-hard-soft rock） were built. And each type model was further divided into three types when the experiments were carried out. To reduce the errors of cutting load caused by manually configured rock in each test, the cutting load of soft rock was taken as a benchmark, and the differences of the cutting load of the different structures of rocks and the soft rock were used to reflect the cutting load change rules of the HCM. The results indicate that, the cutting load of only the HCM top cutting hard rock is larger than that of only the HCM bottom cutting hard rock for dextral HCM, and the cutting load fluctuation is larger, too. However, when the top and the bottom of the HCM cutting hard rock simultaneously, its cutting load is the largest, but the cutting load fluctuation is the least. And the HCM cutting load increment is increased linearly with the increase of rock compressive strength. The HCM cutting load increment is increased exponentially with the increase of hard rock cutting thickness.展开更多
The study aimed at evaluating the nutrient and nutraceutical potentials of the selected seaweed biomass namely Ulva lactuca and Kappaphycus alvarezii. The selected seaweeds were found to be rich in macro and micronutr...The study aimed at evaluating the nutrient and nutraceutical potentials of the selected seaweed biomass namely Ulva lactuca and Kappaphycus alvarezii. The selected seaweeds were found to be rich in macro and micronutrients. Kappaphycus contained high amount of ash when compared to U. lactuca. It is revealed that the mercury level in U. lactuca was 0.017 ppm and it was not detected in K. alvarezii. The heavy metal concentration in the selected seaweeds was within the tolerable value reported as quality criteria for edible seaweeds. These seaweeds were also found to be rich sources of vitamin antioxidants namely Vitamin C, total carotenoid, beta carotene, total chlorophyll and polyphenol. The phytochemical screening of the selected seaweeds showed that both seaweeds contained carbohydrates, protein, gums and mulicage, phenols, starch and quinones. Alkaloids was absent in Kappaphycus, saponins was moderate in U. actuca when compared to Kappaphycus. Glycosides, flavonoids, tannins and terpenoids were absent in both the species. The selected seaweeds also possess antibacterial activity. The selected biomass could be recommended for use in dietaries to combat protein energy malnutrition and in particular micronutrient deficiencies.展开更多
文摘Aim To investigate the chemical constituents of Piper wallichii. Methods Five compounds were isolated by silica gel column chromatography and Sephadex LH-20 gel column chromatography, and the structures of compounds were identified by spectral analysis. Result Five compounds were identified as piperlonguminine （trans, trans） （1）, 4-hydroxy-3,5-dimethoxy-benzoic acid （2）, galgravin （3）, β-sitosterol （4）, and daucosterol （5）. Conclusion Five compounds were isolated from Piper wallichii for the first time, and compounds 1 -3 were isolated from this genus far the first time.
基金Project(51005232) supported by the National Natural Science Foundation of ChinaProject(20100481176) supported by the China Postdoctoral Science Foundation
文摘To research the loading charactefistc of rocks with different structures cut by helical cutting mechanism （HCM）, three different structures of rock （hard-soft-hard rock, soft-hard rock and soft-hard-soft rock） were built. And each type model was further divided into three types when the experiments were carried out. To reduce the errors of cutting load caused by manually configured rock in each test, the cutting load of soft rock was taken as a benchmark, and the differences of the cutting load of the different structures of rocks and the soft rock were used to reflect the cutting load change rules of the HCM. The results indicate that, the cutting load of only the HCM top cutting hard rock is larger than that of only the HCM bottom cutting hard rock for dextral HCM, and the cutting load fluctuation is larger, too. However, when the top and the bottom of the HCM cutting hard rock simultaneously, its cutting load is the largest, but the cutting load fluctuation is the least. And the HCM cutting load increment is increased linearly with the increase of rock compressive strength. The HCM cutting load increment is increased exponentially with the increase of hard rock cutting thickness.
文摘The study aimed at evaluating the nutrient and nutraceutical potentials of the selected seaweed biomass namely Ulva lactuca and Kappaphycus alvarezii. The selected seaweeds were found to be rich in macro and micronutrients. Kappaphycus contained high amount of ash when compared to U. lactuca. It is revealed that the mercury level in U. lactuca was 0.017 ppm and it was not detected in K. alvarezii. The heavy metal concentration in the selected seaweeds was within the tolerable value reported as quality criteria for edible seaweeds. These seaweeds were also found to be rich sources of vitamin antioxidants namely Vitamin C, total carotenoid, beta carotene, total chlorophyll and polyphenol. The phytochemical screening of the selected seaweeds showed that both seaweeds contained carbohydrates, protein, gums and mulicage, phenols, starch and quinones. Alkaloids was absent in Kappaphycus, saponins was moderate in U. actuca when compared to Kappaphycus. Glycosides, flavonoids, tannins and terpenoids were absent in both the species. The selected seaweeds also possess antibacterial activity. The selected biomass could be recommended for use in dietaries to combat protein energy malnutrition and in particular micronutrient deficiencies.
