This article described the characteristics of the liquid nitrogen engine's ideal open cycle.Using two interconnecting strokes to achieve the power output can mitigate the trade-off between high efficiency and the ...This article described the characteristics of the liquid nitrogen engine's ideal open cycle.Using two interconnecting strokes to achieve the power output can mitigate the trade-off between high efficiency and the potential mechanical complexity of multiple-cylinder engines. The total specific energy of the binary media (methane-nitrogen) cycle system could be much higher than the unitary medium (liquid nitrogen) cycle system. By theoretical analysis, the reasonably acceptable driving range proved the feasibility of the liquid nitrogen engine used for supplying power for a lightweight car.展开更多
To investigate the dynamics of plasma cAMP/cGMP in patients during cardiac surgery, and its relationship to traumatic stress. Methods: Sixteen patients, aged 19.31 years± 10.4 years , who underwent an open heart ...To investigate the dynamics of plasma cAMP/cGMP in patients during cardiac surgery, and its relationship to traumatic stress. Methods: Sixteen patients, aged 19.31 years± 10.4 years , who underwent an open heart operation with cardiopulmonary bypass (CPB) and hy pother mia were served as subjects. The arterial plasma concentrations of cyclic adenos ine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were measured by radioimmunoassay 2 hours before operation, after heparinization, 20 minutes following CPB, at the end of the operation, and 24 and 72 hours postoperatively, respectiv ely. The patients preoperative blood samples were heparinized and the venous b lood samples of 30 healthy blood donors were taken to measure the levels of cAMP and cGMP as heparin and normal controls separately. Results: There were no statistical difference among the heparin control, preoperative level and normal control. The peak values of cAMP and cGM P occurred during CPB and plasma cAMP levels changed synchronously with intensit ies of operative stimulus to human body. However cGMP level was mainly related t o the operative stimulus to the heart and CPB. The cAMP value was positivel y correlated with the cGMP value (r= 0.6313 , P< 0.001 ).Conclusions: Dynamic variation of plasma cyclic ribonucleotide can be considered as a reference parameter for intensity of traumatic stress.展开更多
文摘This article described the characteristics of the liquid nitrogen engine's ideal open cycle.Using two interconnecting strokes to achieve the power output can mitigate the trade-off between high efficiency and the potential mechanical complexity of multiple-cylinder engines. The total specific energy of the binary media (methane-nitrogen) cycle system could be much higher than the unitary medium (liquid nitrogen) cycle system. By theoretical analysis, the reasonably acceptable driving range proved the feasibility of the liquid nitrogen engine used for supplying power for a lightweight car.
文摘To investigate the dynamics of plasma cAMP/cGMP in patients during cardiac surgery, and its relationship to traumatic stress. Methods: Sixteen patients, aged 19.31 years± 10.4 years , who underwent an open heart operation with cardiopulmonary bypass (CPB) and hy pother mia were served as subjects. The arterial plasma concentrations of cyclic adenos ine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were measured by radioimmunoassay 2 hours before operation, after heparinization, 20 minutes following CPB, at the end of the operation, and 24 and 72 hours postoperatively, respectiv ely. The patients preoperative blood samples were heparinized and the venous b lood samples of 30 healthy blood donors were taken to measure the levels of cAMP and cGMP as heparin and normal controls separately. Results: There were no statistical difference among the heparin control, preoperative level and normal control. The peak values of cAMP and cGM P occurred during CPB and plasma cAMP levels changed synchronously with intensit ies of operative stimulus to human body. However cGMP level was mainly related t o the operative stimulus to the heart and CPB. The cAMP value was positivel y correlated with the cGMP value (r= 0.6313 , P< 0.001 ).Conclusions: Dynamic variation of plasma cyclic ribonucleotide can be considered as a reference parameter for intensity of traumatic stress.
