A SiC asymmetric cell trench MOSFET with a split gate and integrated p^(+)-poly Si/SiC heterojunction freewheeling diode

A new SiC asymmetric cell trench metal–oxide–semiconductor field effect transistor(MOSFET)with a split gate(SG)and integrated p^(+)-poly Si/SiC heterojunction freewheeling diode(SGHJD-TMOS)is investigated in this article.The SG structure of the SGHJD-TMOS structure can effectively reduce the gate-drain capacitance and reduce the high gateoxide electric field.The integrated p^(+)-poly Si/SiC heterojunction freewheeling diode substantially improves body diode characteristics and reduces switching losses without degrading the static characteristics of the device.Numerical analysis results show that,compared with the conventional asymmetric cell trench MOSFET(CA-TMOS),the high-frequency figure of merit(HF-FOM,R_(on,sp)×Q_(gd,sp))is reduced by 92.5%,and the gate-oxide electric field is reduced by 75%.In addition,the forward conduction voltage drop(V_(F))and gate-drain charge(Q_(gd))are reduced from 2.90 V and 63.5μC/cm^(2) in the CA-TMOS to 1.80 V and 26.1μC/cm^(2) in the SGHJD-TMOS,respectively.Compared with the CA-TMOS,the turn-on loss(E_(on)) and turn-off loss(E_(off)) of the SGHJD-TMOS are reduced by 21.1%and 12.2%,respectively.

Implementation of regional Acute Stroke Care Map increases thrombolysis rates for acute ischaemic stroke in Chinese urban area in only 3 months

Background The rate of intravenous thrombolysis for acute ischaemic stroke remains low in China.We investigated whether the implementation of a citywide Acute Stroke Care Map(ASCaM)is associated with an improvement of acute stroke care quality in a Chinese urban area.Methods The ASCaM comprises 10 improvement strategies and has been implemented through a network consisting of 20 tertiary hospitals.We identified 7827 patients with ischaemic stroke admitted from April to October 2017,and 506 patients underwent thrombolysis were finally included for analysis.Results Compared with‘pre-ASCaM period’,we observed an increased rate of administration of tissue plasminogen activator within 4.5 hours(65.4% vs 54.5%;adjusted OR,1.724;95% CI 1.21 to 2.45;p=0.003)during‘ASCaM period’.In multivariate analysis models,‘ASCaM period’was associated with a significant reduction in onset-to door time(114.1±55.7 vs 135.7±58.4 min,p=0.0002)and onset-to needle time(ONT)(169.2±58.1 vs 195.6±59.3 min,p<0.0001).Yet no change was found in door-to needle time.Clinical outcomes such as symptomatic intracranial haemorrhage,favourable functional outcome(modified Rankin Scale≤2)and in-hospital mortality remained unchanged.Conclusion The implementation of ASCaM was significantly associated with increased rates of intravenous thrombolysis and shorter ONT.The ASCaM may,in proof-of principle,serve as a model to reduce treatment delay and increase thrombolysis rates in Chinese urban areas and possibly other highly populated Asian regions.

Assessing platelet function may reduce platelet transfusion requirements in women in thrombocytopenia undergoing cesarean section

Thrombocytopenia is a common comorbidity during pregnancy.A platelet(PLT)count of<100×109/L is used as the diagnosis for thrombocytopenia.The major adverse effect of thrombocytopenia in the clinical setting is hemorrhage of varying severity.[1]The causes of thrombocytopenia during pregnancy are distinct from those of other diseases.Gestational thrombocytopenia accounts for>75%of thrombocytopenia cases in pregnant women and occurs in 5%to 8%of pregnancies.Other causes of thrombocytopenia include hemolysis,elevated liver enzymes.

Stereoselective Photochemical Reaction of Cyclohexyl Phenyl Ketone within Lytropic Liquid Crystals Formed by Chiral Ionic Liquids

Irradiation of cyclohexyl phenyl ketone （1） results in either intra- or intermolecular hydrogen abstraction to af- ford compounds 1-phenylhept-6-en-l-one （2） and a-cyclohexyl benzyl alcohol （3） as photoproducts, in which 3 has a pair of enantiomers. Herein, two types of chiral hexagonal liquid crystals were prepared to direct the enantioselec- tive photochemical reaction of 1. One of the hexagonal liquid crystals is composed of 1-tetradecyl-3-methyl- imidazolium bromide/p-xylene/H2O with the modification by a chiral inductor. The other one is formed by chiral （S）-3-hexadecyl-1-（1-hydroxy-propan-2-yl）-imidazolium bromide/p-xylene/H2O. The product analysis shows that the latter one can be used as a microreactor to achieve stereoselective photochemical reaction, while the former one produced compound 3 with no enantioselectivity at all.