On the pressure resistant clothing,suitcases and bags,a load-bearing zipper is an effective device to keep pressure and fold-unfold the structure.The load-bearing zipper should has a high-strength and moderate operation force.A model of zipper was established and the changing process bearing the breaking strength crosswise of chain was calculated by finite element software Ansys,and the structure sizes were improved according on the fracture mechanism.A kind of high strength zipper was obtained by the continuous molding nylon zipper tooth and the properties were measured.An air pressure bag was made to evaluate the performance in use.Results indicate that the breaking strength crosswise of chain reaches 2000 N/25 mm with a moderate 14.5 N tab pull-off strength,which means the load-bearing zipper could meet the requirements of high strength pressure resistant structures.

The sealing performance is directly related to the safety,reliability and mission success rate of aerospace equipment.The sealing performance of rubber seals and the optimized design of the compression force directly affect the performance and work efficiency of the equipment.Based on the hyperelastic Mooney-Rivlin model of nonlinear materials,the mechanical properties of rubber are simulated,and a finite element model of rubber seals is established.Through simulation analysis,the effects of different cross-section dimensions and compression amounts on the sealing performance are studied and compared,and key parameters such as the contact stress distribution,maximum contact stress,and compression force.The size of the fillet affects the final deformation and the contact state.By optimizing the geometric parameters,the compression force can be reduced while ensuring the sealing performance,providing a theoretical basis for the optimized design of rubber seals.

BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) is the endoscopic modality of choice for the treatment of biliary and pancreatic diseases. However, patients with cirrhosis, particularly those with decompensated cirrhosis, are believed to be at increased risk for complications associated with ERCP. There is a paucity of literature describing the outcomes of ERCP for patients with cirrhosis. This study aimed to investigate the outcomes of ERCP for cirrhosis patients, especially adverse events, and evaluated its safety and efficacy. METHODS: We performed a multicenter, retrospective study of all patients at Beijing Friendship Hospital affiliated to Capital Medical University, Xijing Hospital affiliated to Air Force Military Medical University, Beijing Youan Hospital affiliated to Capital Medical University, and the Fifth Medical Center of the People's Liberation Army General Hospital from June 2003 to August 2019. The adverse events of inpatient ERCP for patients with ( n  = 182) and without liver cirrhosis (controls; n  = 385) were compared. RESULTS: A total of 567 patients underwent ERCP between January 2003 and December 2019 were enrolled in this study. Compared to patients without cirrhosis, patients with cirrhosis were at higher risk for postoperative complications (odds ratio [OR], 4.172; 95% confidence interval [CI], 1.232-7.031; P  < 0.001) such as postoperative pancreatitis (OR, 2.026; 95% CI, 1.002-4.378; P  = 0.001) and cholangitis (OR, 3.903; 95% CI, 1.001-10.038; P  = 0.036). The main indications for ERCP for patients with cirrhosis in this study included choledocholithiasis (101 cases; 55.5%), benign bile duct strictures (46 cases; 25.3%), and malignant bile duct strictures (28 cases; 15.4%). Among them, 23 patients (12.6%) underwent balloon dilation and 79 patients (43.4%) underwent sphincterotomy. Of the patients with cirrhosis, delayed bleeding occurred in ten patients (5.5%), postoperative pancreatitis occurred in 80 patients (44.0%), and postoperative cholangitis occurred in 25 patients (13.7%). An additional multivariate analysis showed that the total bilirubin (TBIL) level (OR, 4.58; 95% CI, 2.37-6.70) and Child-Pugh score of C (OR, 3.11; 95% CI, 1.04-5.37) were risk factors for postoperative complications in patients with cirrhosis. CONCLUSIONS Compared with the general population of patients undergoing ERCP, patients with cirrhosis were more prone to postoperative pancreatitis and cholangitis. TBIL levels and Child-Pugh scores were risk factors for postoperative complications in patients with cirrhosis.
Humans ; Cholangiopancreatography, Endoscopic Retrograde/adverse effects* ; Retrospective Studies ; Constriction, Pathologic ; Risk Factors ; Liver Cirrhosis/complications* ; Pancreatitis/etiology* ; Postoperative Complications/epidemiology* ; Cholangitis