Flavonoids are the most widely used in the field of the food, medicine, and cosmetic due to their pharmacological functions and biological activities, such as anti-tumor, anti-inflammatory and antioxidation. This work...Flavonoids are the most widely used in the field of the food, medicine, and cosmetic due to their pharmacological functions and biological activities, such as anti-tumor, anti-inflammatory and antioxidation. This work described the assignment of purity values to 3 flavonoids certified reference materials (CRMs) including baicalein, 5,7-dihydoxy flavones and naringenine which?were developed in this study according to the ISO Guides 34 and 35. The qualitative analysis was performed by liquid chromatography-mass spectrometry (LC-MS) and infrared spectroscopy (IR). The CRMs’ purity values were assigned based on the weighted average of quantitative nuclear magnetic resonance method and mass balance approach with high resolution liquid chromatography-VWD. All the three CRMs with following value mass fractions: baicalein at a certified purity P ± U (k = 2) of 98.8% ± 0.8%;5,7-dihydoxy flavones of 99.1% ± 0.7% and naringenine of 99.5% ± 1.0% respectively. The homogeneity of the CRMs was determined by an in-house validated liquid chromatographic method. Potential degradation during storage was also investigated and a shelf-life based on this value was established.展开更多
In boron-doped p+-n crystalline silicon(Si) solar cells, p-type boron doping control and surface passivation play a vital role in the realization of high-efficiency and low cost pursuit. In this study, boron-doped p...In boron-doped p+-n crystalline silicon(Si) solar cells, p-type boron doping control and surface passivation play a vital role in the realization of high-efficiency and low cost pursuit. In this study, boron-doped p+-emitters are formed by boron diffusion in an open-tube furnace using borontribromide(BBr3) as precursor. The formed emitters are characterized in detail in terms of shape of the doping profile, surface doping concentration, junction depth, sheet resistance and removal of the boron-rich layer(BRL). In the aspect of BRL removal, three different methods were adopted to investigate their influence on device performance. The results demonstrate that our proposed chemical etch treatment(CET) with the proper etching time could be an effective way to remove the BRL.After removal of the BRL, Al;O;/SiN;stacks are deposited by atomic layer deposition(ALD) and plasma-enhanced chemical vapor deposition(PECVD) to passivate the cell surface. It was found that a reasonably-high implied Voc of 680 mV has been achieved for the fabricated n-type Si solar cells.展开更多
文摘Flavonoids are the most widely used in the field of the food, medicine, and cosmetic due to their pharmacological functions and biological activities, such as anti-tumor, anti-inflammatory and antioxidation. This work described the assignment of purity values to 3 flavonoids certified reference materials (CRMs) including baicalein, 5,7-dihydoxy flavones and naringenine which?were developed in this study according to the ISO Guides 34 and 35. The qualitative analysis was performed by liquid chromatography-mass spectrometry (LC-MS) and infrared spectroscopy (IR). The CRMs’ purity values were assigned based on the weighted average of quantitative nuclear magnetic resonance method and mass balance approach with high resolution liquid chromatography-VWD. All the three CRMs with following value mass fractions: baicalein at a certified purity P ± U (k = 2) of 98.8% ± 0.8%;5,7-dihydoxy flavones of 99.1% ± 0.7% and naringenine of 99.5% ± 1.0% respectively. The homogeneity of the CRMs was determined by an in-house validated liquid chromatographic method. Potential degradation during storage was also investigated and a shelf-life based on this value was established.
基金Project supported by the Beijing Municipal Science and Technology Commission,China(No.Z151100003515003)the Beijing Natural Science Foundation(No.4173077,2184112)+3 种基金the Fundamental Research Funds for the Central Universities,China(Nos.FRF-BR-16-018A,FRF-TP-17-022A1,06400071)the National Natural Science Foundation of China(Nos.110751402347,61274134,51402064,61274059,51602340)the Beijing Municipal Innovation and Research Base,China(No.Z161100005016095)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2015387)
文摘In boron-doped p+-n crystalline silicon(Si) solar cells, p-type boron doping control and surface passivation play a vital role in the realization of high-efficiency and low cost pursuit. In this study, boron-doped p+-emitters are formed by boron diffusion in an open-tube furnace using borontribromide(BBr3) as precursor. The formed emitters are characterized in detail in terms of shape of the doping profile, surface doping concentration, junction depth, sheet resistance and removal of the boron-rich layer(BRL). In the aspect of BRL removal, three different methods were adopted to investigate their influence on device performance. The results demonstrate that our proposed chemical etch treatment(CET) with the proper etching time could be an effective way to remove the BRL.After removal of the BRL, Al;O;/SiN;stacks are deposited by atomic layer deposition(ALD) and plasma-enhanced chemical vapor deposition(PECVD) to passivate the cell surface. It was found that a reasonably-high implied Voc of 680 mV has been achieved for the fabricated n-type Si solar cells.