Aerosol samples were collected from three typical areas during three years: 1) north suburb of Shanghai city (NSSC); 2) north part of Shanghai city; 3) a lead-zinc smeltery and its surrounding areas. The hair samples ...Aerosol samples were collected from three typical areas during three years: 1) north suburb of Shanghai city (NSSC); 2) north part of Shanghai city; 3) a lead-zinc smeltery and its surrounding areas. The hair samples were collected from lead-exposed workers and control people. Aerosol samples have been analyzed by PIXE, and hair samples by EDXRF (energy-dispersive X-ray fluorescence) method. S, Cl, K, Ca, Mn, Fe, Cu, Zn, Pb etc were detected in most of the aerosol and hair samples. According to the analytical results, the compositions of NSSC aerosol samples were quite similar to those from north part of Shanghai city, both the lead concentrations of these samples were less than the limit of the National Standard (70 μ g/m3); There was serious air pollution in smeltery and its surrounding areas. Especially, the lead concentration in the aerosol exceeded 200 μg/m3; The average lead concentration of hair samples for half-year exposed group was about 3-fold higher than that of unexposed group.展开更多
This paper describes the scanning nuclear microprobe facilities established at the Shanghai Institute of Nuclear Research. The Russion quadruplet constructed with four magnetic quadrupolets is used for microbeam forma...This paper describes the scanning nuclear microprobe facilities established at the Shanghai Institute of Nuclear Research. The Russion quadruplet constructed with four magnetic quadrupolets is used for microbeam formation. The long focus of the lens makes the working distance long enough to accommodate the scanning coils and the detectors for PIXE, RBS, RFS, NRA and SE experiments. A 5 μm focussed beam is scanned continously by a pair of coils. A multiparameter multidetector data system for the nuclear microprobe is based on the idea of Total quantitative scanning analysis (TQSA) suggested by Melbourne University. A digital graphic displayer is a good substitute for an ordinary storage oscilloscope for on- line scanned area monitoring. The new microprobe meets high demands of biologists and geologists on applications.展开更多
The large fragment of E.coli DNA polymerase I is imaged by scanning tunneling microscope. The specimen is deposited on highly oriented pyrolytic graphite surface, and then covered with pure paraffin oil in order to ma...The large fragment of E.coli DNA polymerase I is imaged by scanning tunneling microscope. The specimen is deposited on highly oriented pyrolytic graphite surface, and then covered with pure paraffin oil in order to maintain hydration of the molecules. Images of the enzyme reveal an ellipsoid shape of 5.5-6.0nm wide and 7.0 -7.5 nm long. The conformation of the enzyme is in agreement with the model derived from X- ray crystallography studies.展开更多
文摘Aerosol samples were collected from three typical areas during three years: 1) north suburb of Shanghai city (NSSC); 2) north part of Shanghai city; 3) a lead-zinc smeltery and its surrounding areas. The hair samples were collected from lead-exposed workers and control people. Aerosol samples have been analyzed by PIXE, and hair samples by EDXRF (energy-dispersive X-ray fluorescence) method. S, Cl, K, Ca, Mn, Fe, Cu, Zn, Pb etc were detected in most of the aerosol and hair samples. According to the analytical results, the compositions of NSSC aerosol samples were quite similar to those from north part of Shanghai city, both the lead concentrations of these samples were less than the limit of the National Standard (70 μ g/m3); There was serious air pollution in smeltery and its surrounding areas. Especially, the lead concentration in the aerosol exceeded 200 μg/m3; The average lead concentration of hair samples for half-year exposed group was about 3-fold higher than that of unexposed group.
基金The Project Supported by the Foundation of Academic Sinica
文摘This paper describes the scanning nuclear microprobe facilities established at the Shanghai Institute of Nuclear Research. The Russion quadruplet constructed with four magnetic quadrupolets is used for microbeam formation. The long focus of the lens makes the working distance long enough to accommodate the scanning coils and the detectors for PIXE, RBS, RFS, NRA and SE experiments. A 5 μm focussed beam is scanned continously by a pair of coils. A multiparameter multidetector data system for the nuclear microprobe is based on the idea of Total quantitative scanning analysis (TQSA) suggested by Melbourne University. A digital graphic displayer is a good substitute for an ordinary storage oscilloscope for on- line scanned area monitoring. The new microprobe meets high demands of biologists and geologists on applications.
文摘The large fragment of E.coli DNA polymerase I is imaged by scanning tunneling microscope. The specimen is deposited on highly oriented pyrolytic graphite surface, and then covered with pure paraffin oil in order to maintain hydration of the molecules. Images of the enzyme reveal an ellipsoid shape of 5.5-6.0nm wide and 7.0 -7.5 nm long. The conformation of the enzyme is in agreement with the model derived from X- ray crystallography studies.
