Presented is design concept for key parameters o f the reverse conducting gate commutated thyristor (RC-GCT),such as the thickness and concentration of n-base region and the transparent anode region,and the wi dth o...Presented is design concept for key parameters o f the reverse conducting gate commutated thyristor (RC-GCT),such as the thickness and concentration of n-base region and the transparent anode region,and the wi dth of separation region between asymmetric GCT and PIN diode.A structure model of the RC-GCT is set up based on the design concept and its characteristics are analyzed.The simulation results show the design concept is reasonable.展开更多
Τhe efficiency of a Mewis propeller duct by the analysis of ship operational data is examined.The analysis employs data collected with high frequency for a three-year period for two siter vessels,one of them fitted w...Τhe efficiency of a Mewis propeller duct by the analysis of ship operational data is examined.The analysis employs data collected with high frequency for a three-year period for two siter vessels,one of them fitted with a Mewis type duct.Our approach to the problem of identifying improvements in the operational performance of the ship equipped with the duct is two-fold.Firstly,we proceed with the calculation of appropriate Key Performance Indicators to monitor vessels performance in time for different operational periods and loading conditions.An extensive pre-processing stage is necessary to prepare a dataset free from datapoints that could impair the analysis,such as outliers,as well as the appropriate preparations for a meaningful KPI calculation.The second approach concerns the development of multiple linear regression problem for the prediction of main engine fuel oil consumption based on operational and weather parameters,such as ship’s speed,mean draft,trim,rudder angle and the wind speed.The aim is to quantify reductions due to the Mewis duct for several scenarios.Key results of the studies reveal a contribution of the Mewis duct mainly in laden condition,for lower speed range and in the long-term period after dry-docking.展开更多
Objectives:To determine immediate and long-term follow-up of transcatheter closure of patent ductus arteriosus(PDA)in children.Background:National antibiotic prophylaxis(AP)guideline for infective endocarditis changed...Objectives:To determine immediate and long-term follow-up of transcatheter closure of patent ductus arteriosus(PDA)in children.Background:National antibiotic prophylaxis(AP)guideline for infective endocarditis changed after 2009,the effect on practice of PDA closure is unknown.Methods:Observational single center study analyzing follow-up of PDA closure comparing two time periods before(2002–2009)and after(2010–2019)changes in AP guideline.Results:332 patients(68.1%female),median(interquartile range)age 3.0 years(1.5–5.7)and body weight 14.0 kg(10.0–19.3),were enrolled.PDA morphology was conical type A(50.3%),window type B(1.2%),tubular type C(40.1%),complex type D(2.1%),elongated type E(0.9%)and other(5.4%).Minimal PDA diameter and length were 1.9 mm(1.3–2.5)and 8.0 mm(6.2–10.2).PDA was closed using coils(56.3%),Amplatzer Duct Occluders(41.9%)and others(1.8%).Complete closure rate was 61.1%at catheter intervention,72.3%on day 1,87.7%after 6 months and 98.4%at last follow-up on echocardiography.Moderate complication rate(severity level 3)was 4.2%and major complication rate(severity level 4)0.3%,with no catastrophic complications(severity level 5).Annual PDA closure rate declined in the second time period(22.6/year vs.15.5/year,p=0.018),PDA size increased(1.6 mm vs.2.0 mm,p=0.002)and proportion of coils decreased(72.4%vs.37.1%,p<0.001).Conclusions:Interventional closure of PDA is associated with excellent closure rates during follow-up(>98%)and only a small number of complications leading to reintervention or surgery.Change in AP guidelines changed indication for and practice of PDA closure.展开更多
文摘Presented is design concept for key parameters o f the reverse conducting gate commutated thyristor (RC-GCT),such as the thickness and concentration of n-base region and the transparent anode region,and the wi dth of separation region between asymmetric GCT and PIN diode.A structure model of the RC-GCT is set up based on the design concept and its characteristics are analyzed.The simulation results show the design concept is reasonable.
文摘Τhe efficiency of a Mewis propeller duct by the analysis of ship operational data is examined.The analysis employs data collected with high frequency for a three-year period for two siter vessels,one of them fitted with a Mewis type duct.Our approach to the problem of identifying improvements in the operational performance of the ship equipped with the duct is two-fold.Firstly,we proceed with the calculation of appropriate Key Performance Indicators to monitor vessels performance in time for different operational periods and loading conditions.An extensive pre-processing stage is necessary to prepare a dataset free from datapoints that could impair the analysis,such as outliers,as well as the appropriate preparations for a meaningful KPI calculation.The second approach concerns the development of multiple linear regression problem for the prediction of main engine fuel oil consumption based on operational and weather parameters,such as ship’s speed,mean draft,trim,rudder angle and the wind speed.The aim is to quantify reductions due to the Mewis duct for several scenarios.Key results of the studies reveal a contribution of the Mewis duct mainly in laden condition,for lower speed range and in the long-term period after dry-docking.
文摘Objectives:To determine immediate and long-term follow-up of transcatheter closure of patent ductus arteriosus(PDA)in children.Background:National antibiotic prophylaxis(AP)guideline for infective endocarditis changed after 2009,the effect on practice of PDA closure is unknown.Methods:Observational single center study analyzing follow-up of PDA closure comparing two time periods before(2002–2009)and after(2010–2019)changes in AP guideline.Results:332 patients(68.1%female),median(interquartile range)age 3.0 years(1.5–5.7)and body weight 14.0 kg(10.0–19.3),were enrolled.PDA morphology was conical type A(50.3%),window type B(1.2%),tubular type C(40.1%),complex type D(2.1%),elongated type E(0.9%)and other(5.4%).Minimal PDA diameter and length were 1.9 mm(1.3–2.5)and 8.0 mm(6.2–10.2).PDA was closed using coils(56.3%),Amplatzer Duct Occluders(41.9%)and others(1.8%).Complete closure rate was 61.1%at catheter intervention,72.3%on day 1,87.7%after 6 months and 98.4%at last follow-up on echocardiography.Moderate complication rate(severity level 3)was 4.2%and major complication rate(severity level 4)0.3%,with no catastrophic complications(severity level 5).Annual PDA closure rate declined in the second time period(22.6/year vs.15.5/year,p=0.018),PDA size increased(1.6 mm vs.2.0 mm,p=0.002)and proportion of coils decreased(72.4%vs.37.1%,p<0.001).Conclusions:Interventional closure of PDA is associated with excellent closure rates during follow-up(>98%)and only a small number of complications leading to reintervention or surgery.Change in AP guidelines changed indication for and practice of PDA closure.
