研究了相敏式激光啁啾色散光谱法在高吸收度情况下的应用.用窄频半导体激光器作为光源,利用一工作于载波抑制模式的铌酸锂电光强度调制器调制单频激光,在单频激光两侧产生两个边频分量,并通过两边频分量产生外差干涉信号.利用外差干涉...研究了相敏式激光啁啾色散光谱法在高吸收度情况下的应用.用窄频半导体激光器作为光源,利用一工作于载波抑制模式的铌酸锂电光强度调制器调制单频激光,在单频激光两侧产生两个边频分量,并通过两边频分量产生外差干涉信号.利用外差干涉的相位波动来测量甲烷气体位于1653.7 nm附近的折射率波动,通过气体折射率与吸收系数之间的Kramers-Kronig关系计算甲烷气体浓度.传统的波长调制光谱法受限于郎伯-比尔定律,在应用于高吸收度的情况时,存在灵敏度下降的问题,甚至出现随气体浓度上升输出信号反而下降的现象.实验结果显示,相同实验条件下,波长调制光谱法的线性测量范围为38.1—1500 ppm·m,线性测量的动态范围仅为16 d B;而相敏式激光啁啾色散光谱法在很大的吸收度范围内均具有线性输出,检出限低至47.3 ppm·m,线性测量范围上限为174825 ppm·m,具有超过35 d B的动态范围.展开更多
The interaction mechanism of collector DLZ in the flotation process of chalcopyrite and pyrite was investigated through flotation experiments,zeta potential measurements and infrared spectrum analysis.Flotation test r...The interaction mechanism of collector DLZ in the flotation process of chalcopyrite and pyrite was investigated through flotation experiments,zeta potential measurements and infrared spectrum analysis.Flotation test results indicate that DLZ is the selective collector of chalcopyrite.Especially,the recovery of chalcopyrite is higher than 90% in neutral and weak alkaline systems,while the recovery of pyrite is less than 10%.When using CaO as pH regulator,at pH=7-11,the floatability of pyrite is depressed and the recovery is less than 5%.Zeta potential analysis shows that the zeta potential of chalcopyrite decreases more obviously than that of pyrite after interaction with DLZ,confirming that collector DLZ shows selectivity to chalcopyrite and pyrite.And FTIR results reveal that the flotation selectivity of collector DLZ is due to chemical absorption onto chalcopyrite surface and only physical absorption onto pyrite surface.展开更多
Objectives Partial hepatectomy induces a rapid transformation within the remnant liver, prompting a wave of hepatocyte mitosis which abates when the lost cell mass has been recovered. The mechanism of co-ordinated con...Objectives Partial hepatectomy induces a rapid transformation within the remnant liver, prompting a wave of hepatocyte mitosis which abates when the lost cell mass has been recovered. The mechanism of co-ordinated control of metabolism and maintenance of function during this period of dynamic change is incompletely understood. Furthermore, the biochemical basis of growth regulation in the regenerating liver has not been well defined. We have studied human liver regeneration using in vivo 31-phosphorus magnetic resonance spectroscopy (31 P MRS). This non-invasive technique allows assay of high-energy phosphate compounds and also of phospholipid metabolites thought to be involved in cellular renewal processes.Methods Five patients undergoing liver resection were studied. Hepatic metabolism was evaluated using 31P MRS before surgery and on postoperative days 2,4,6 and 14. Estimation of liver volume by magnetic resonance imaging and blood sampling for biochemistry were performed at the same time points.Results We found that the regenerative response following loss of liver parenchyma produced a reversible decline in energy state which necessitated compensatory adjustments in liver synthetic and excretory (unctions. Volume regain was associated with alterations in phospholipid metabolism, which normalized when the hepatic growth spurt was completed.Conclusion These observations indicate that modulation of hepatocyte energy economy is necessary for the integrated recovery of liver cell mass and function. We propose that deficient hepatic energy production may explain the mechanism of liver failure after hepatectomy, and suggest that in vivo measurement of liver metabolism may provide a rational basis for the development and evaluation of hepatic support strategies.展开更多
The phenomenon that different molecular packing modes in aggregates result in different optical properties has attracted intense attention,since it can provide useful information to establish the relationship between ...The phenomenon that different molecular packing modes in aggregates result in different optical properties has attracted intense attention,since it can provide useful information to establish the relationship between the micro-and macro-world.In this paper,DBTDO-DMAC was designed with 9,10-dihydro-9,9-dimethylacridine(DMAC)as electron donor.DBTDO-DPA and DBTDO-Cz were designed for comparison,which adopted diphenylamine(DPA)with twisted structure and carbazole(Cz)with planar structure as donors,respectively.As expected,two polymorphs(Crystal G and Crystal Y)of DBTDO-DMAC were obtained and exhibited distinct properties.Crystal G originating from planar conformation exhibited mechanochromism(MC)phenomenon and the emission color changed from green to yellow with a redshift of 35 nm after grinding.Nevertheless,Crystal Y with folded conformation displayed obvious room-temperature phosphorescence(RTP)with yellow afterglow.Careful single crystal analyses,powder X-ray diffraction and theoretical calculation reveal that the different emissive behaviors are highly related to the molecular conformation and packing modes.The successful adjustment of molecular conformation provides some guidance in the design of other MC and/or RTP luminogens,broadens the molecule family with the tunable molecular conformation and opens up a new avenue for exploring possible adjustment of molecular packing in aggregates.展开更多
文摘研究了相敏式激光啁啾色散光谱法在高吸收度情况下的应用.用窄频半导体激光器作为光源,利用一工作于载波抑制模式的铌酸锂电光强度调制器调制单频激光,在单频激光两侧产生两个边频分量,并通过两边频分量产生外差干涉信号.利用外差干涉的相位波动来测量甲烷气体位于1653.7 nm附近的折射率波动,通过气体折射率与吸收系数之间的Kramers-Kronig关系计算甲烷气体浓度.传统的波长调制光谱法受限于郎伯-比尔定律,在应用于高吸收度的情况时,存在灵敏度下降的问题,甚至出现随气体浓度上升输出信号反而下降的现象.实验结果显示,相同实验条件下,波长调制光谱法的线性测量范围为38.1—1500 ppm·m,线性测量的动态范围仅为16 d B;而相敏式激光啁啾色散光谱法在很大的吸收度范围内均具有线性输出,检出限低至47.3 ppm·m,线性测量范围上限为174825 ppm·m,具有超过35 d B的动态范围.
基金Project(50674102) supported by the National Natural Science Foundation of China
文摘The interaction mechanism of collector DLZ in the flotation process of chalcopyrite and pyrite was investigated through flotation experiments,zeta potential measurements and infrared spectrum analysis.Flotation test results indicate that DLZ is the selective collector of chalcopyrite.Especially,the recovery of chalcopyrite is higher than 90% in neutral and weak alkaline systems,while the recovery of pyrite is less than 10%.When using CaO as pH regulator,at pH=7-11,the floatability of pyrite is depressed and the recovery is less than 5%.Zeta potential analysis shows that the zeta potential of chalcopyrite decreases more obviously than that of pyrite after interaction with DLZ,confirming that collector DLZ shows selectivity to chalcopyrite and pyrite.And FTIR results reveal that the flotation selectivity of collector DLZ is due to chemical absorption onto chalcopyrite surface and only physical absorption onto pyrite surface.
文摘Objectives Partial hepatectomy induces a rapid transformation within the remnant liver, prompting a wave of hepatocyte mitosis which abates when the lost cell mass has been recovered. The mechanism of co-ordinated control of metabolism and maintenance of function during this period of dynamic change is incompletely understood. Furthermore, the biochemical basis of growth regulation in the regenerating liver has not been well defined. We have studied human liver regeneration using in vivo 31-phosphorus magnetic resonance spectroscopy (31 P MRS). This non-invasive technique allows assay of high-energy phosphate compounds and also of phospholipid metabolites thought to be involved in cellular renewal processes.Methods Five patients undergoing liver resection were studied. Hepatic metabolism was evaluated using 31P MRS before surgery and on postoperative days 2,4,6 and 14. Estimation of liver volume by magnetic resonance imaging and blood sampling for biochemistry were performed at the same time points.Results We found that the regenerative response following loss of liver parenchyma produced a reversible decline in energy state which necessitated compensatory adjustments in liver synthetic and excretory (unctions. Volume regain was associated with alterations in phospholipid metabolism, which normalized when the hepatic growth spurt was completed.Conclusion These observations indicate that modulation of hepatocyte energy economy is necessary for the integrated recovery of liver cell mass and function. We propose that deficient hepatic energy production may explain the mechanism of liver failure after hepatectomy, and suggest that in vivo measurement of liver metabolism may provide a rational basis for the development and evaluation of hepatic support strategies.
基金the National Natural Science Foundation of China(21875130)the Starting Foundation of Tianjin Universitythe Project of“100 Talents Program”of Shanxi Province。
文摘The phenomenon that different molecular packing modes in aggregates result in different optical properties has attracted intense attention,since it can provide useful information to establish the relationship between the micro-and macro-world.In this paper,DBTDO-DMAC was designed with 9,10-dihydro-9,9-dimethylacridine(DMAC)as electron donor.DBTDO-DPA and DBTDO-Cz were designed for comparison,which adopted diphenylamine(DPA)with twisted structure and carbazole(Cz)with planar structure as donors,respectively.As expected,two polymorphs(Crystal G and Crystal Y)of DBTDO-DMAC were obtained and exhibited distinct properties.Crystal G originating from planar conformation exhibited mechanochromism(MC)phenomenon and the emission color changed from green to yellow with a redshift of 35 nm after grinding.Nevertheless,Crystal Y with folded conformation displayed obvious room-temperature phosphorescence(RTP)with yellow afterglow.Careful single crystal analyses,powder X-ray diffraction and theoretical calculation reveal that the different emissive behaviors are highly related to the molecular conformation and packing modes.The successful adjustment of molecular conformation provides some guidance in the design of other MC and/or RTP luminogens,broadens the molecule family with the tunable molecular conformation and opens up a new avenue for exploring possible adjustment of molecular packing in aggregates.
