RESUMEN
In this paper, a carbon dioxide trans-critical refrigerating system which is different from a conventional subcritical refrigerating cycle was studied. The trans-critical carbon dioxide refrigerating systems are based on the Gustav Lorntzen cycle. Emphasis was focused on how to determine the optimal discharge pressure of compressor in CO2 trans-critical cycle. The factors related with the optimal discharge pressure were analyzed. A formula was developed based on cycle simulation, which could be used to predict the optimal discharge pressure of a basic CO2 trans-critical cycle. After further studies on CO2 trans-critical cycles with a regenerator or expander, two more formulas were also developed. These formulas could provide an access to improve the COP of CO2 trans-critical cycle.
RESUMEN
Objective To analyse the pathogenesis,diagnosis and therapy for severe lung contusion.Methods 38 cases of severe lung contusion were observed.On the basis of lung contusion,the patients suffered from mltiple organs trauma,or abdomino-thoracic combinative trauma all of the patients were comprehansive treated with assited ventilation,antishock,high dasage hormone in short-time,dehydrating agent and diuretics therapy etc.Simultaneously,all of concurrent trauma were also reasonably managed timely which including closed thoracic drainage,open chest hemostasis,scavenging hematoma with craniotomy laparosplenotomy,hepatospleno-repair,gastroenterostomy,lower or upper extremity open reduction and extration etc.Results By oxygen inhalation comprehensive treatment did not improve the dyspnea symptom of severe lung contusion when the blood oxygen saturation was lower than 85% and further fall,the severe lung contusion patients were obviously improved by assited ventilation with respirator.Conclusions Using assited ventilation could raise the cure rate for the severe lung contusion,and simultaneously,early diagnosis and comprehansive treatment in time have identical importance.