Because of the softness of cabin material and thin bulkhead,a very distinct shape change oc- curs under the action of internal pressure.The stronger nonlinear relationship between load and bulkhead dis- placement makes the calculation very complicated.For simplicity and considering the influence of big shape change approximately all of load is imposed in several divided stages.The effect from the shape change, caused by previous stages of load,must be figured when next stage of load is imposed.A formula of small shape change is used to calculate each stage of load.In this paper,the main idea is that a nonlinear problem of shape change is linearized in dividing section.

In this paper,the structure,principle and application of combined chemical oxygenerator is described.Its character is that through the adjustable valve controlled by inspiration and expiration,it offers and halts oxygen supply.The utilization rate of oxygen is over 98%.The physico-chemical indices of the oxygen produced reach the national standard for medical oxygen.The experimental results in alti- tude field have shown that it can alleviate the syndroms of acute mountain sickness and reduce heart rate.

Objective: To investigate the treatment of auricle and periauricular arteriovenous malformations. Methods: This is a retrospective study of 30 patients with auricle and periauricular arteriovenous malformations in Changfeng Hospital from February 2012 to March 2017. First, the patients were treated with anhydrous ethanol embolization, followed by transcatheter or direct percutaneous injection of anhydrous ethanol into the malformed vascular tissues. Angiography was performed every time with ethanol injection. The volume of malformed vascular tissues and injection pressure and speed were measured by hand-push angiography. The injection speed of the contrast agent was usually 0.2 ml/s, and malformed vascular tissue volume equal to the dose of the contrast medium filled with the malformed vascular tissues. With the same dose, injection pressure and speed, anhydrous ethanol was injected until all or part of the lesion was cured. The series of treatments were performed with the interval of 1 to 2 months. After embolization, wedge resection combined with lesion was performed to improve the shape of auricle, and to repair the defect of auricle in the cases of obvious auricle hypertrophy. The skin flap adjacent to the auricle was used to treat the auricle defect caused by embolization. Results: The clinical manifestations of 30 patients such as ulcer, bleeding and tinnitus, were improved after 3 times of ethanol embolization. Angiography showed that the abnormal vascular mass completely disappeared in 8 patients. The vascular mass was shrunken by 50% to 75% in 15 patients, and that of 7 patients shrunken less than 50%. Six cases with obvious hypertrophic deformation of auricle were treated with wedge-shaped resection of auricle lesion to reduce the auricles. Three patients suffered partial auricle necrosis after ethanol embolization. They were treated with periauricular pedicle flap to repair the defects. Conclusions Sequential embolization with anhydrous ethanol could effectively improve the clinical manifestations and control the development of the lesions in patients with auricular arteriovenous malformations. When the auricle was obviously hypertrophic and deformed, the shape of the auricle could be improved with surgery.