Laparoscopic liver resection under hemihepatic vascular inflow occlusion using the lowering of hilar plate approach

BACKGROUND： With advances in technology, laparoscopic liver resection is widely accepted. Laparoscopic liver resection under hemihepatic vascular inflow occlusion has advantages over the conventional total hepatic inflow occlusion using the Pringle＇s maneuver, especially in patients with cirrhosis.METHOD： From November 2011 to August 2012, eight consecutive patients underwent laparoscopic liver resection under hemihepatic vascular inflow occlusion using the lowering of hilar plate approach with biliary bougie assistance.RESULTS： The types of liver resection included right hepatectomy（n1）, right posterior sectionectomy（n1）, left hepatectomy and common bile duct exploration（n1）, segment 4b resection（n1）, left lateral sectionectomy（n2）, and wedge resection（n2）. Four patients underwent right and 4 left hemihepatic vascular inflow occlusion. Four patients had cirrhosis. The mean operation time was 176.3 minutes. The mean time taken to achieve hemihepatic vascular inflow occlusion was 24.3minutes. The mean duration of vascular inflow occlusion was54.5 minutes. The mean intraoperative blood loss was 361 mL.No patient required blood transfusion. Postoperatively, one patient developed bile leak which healed with conservative treatment. No postoperative liver failure and mortality occurred. The mean hospital stay of the patients was 7 days.CONCLUSION： Our technique of hemihepatic vascular inflow vascular occlusion using the lowering of hilar plate approachwas safe, and it improved laparoscopic liver resection by minimizing blood loss during liver parenchymal transection.

Bending analysis and control of rolled plate during snake hot rolling

In order to study the bending behavior of aluminum alloy 7050 thick plate during snake hot rolling, several coupled thermo-mechanical finite element(FE) models were established. Effects of different initial thicknesses, pass reductions, speed ratios and offset distances on the bending value of the plate were analyzed. ‘Quasi smooth plate' and optimum offset distance were defined and quasi smooth plate could be acquired by adjusting offset distance, and then bending control equation was fitted. The results show that bending value of the plate as well as the extent of the increase grows with the increase of pass reduction and decrease of initial thickness; the bending value firstly increases and then keeps steady with the ascending speed ratio; the bending value can be reduced by enlarging the offset distance. The optimum offset distance varies for different rolling parameters and it is augmented with the increase of pass reduction and speed ratio and the decrease of initial thickness. A proper offset distance for different rolling parameters can be calculated by the bending control equation and this equation can be a guidance to acquire a quasi smooth plate. The FEM results agree well with experimental results.

Plate Shape Control Theory and Experiment for 20-high Mill

Roll flattening theory is an important part of plate shape control theories for 20-high mill. In order to improve the accuracy of roll flattening calculation for 20-high mill, a new and more accurate roll flattening model was proposed. In this model, the roll barrel was considered as a finite length semi-infinite body. Based on the boundary integral equation method, the numerical solution of the finite length semi-infinite body under the distributed force was obtained and an accurate roll flattening model was established. Coupled with roll bending model and strip plastic deformation, a new and more accurate plate control model for 20-high mill was established. Moreover, the effects of the first intermediate roll taper angle and taper length were analyzed. The tension distribution calculated by analytical model was consistent with the experimental results.