A radio-frequency heating Czochralski technique to obtain LiTaO3 crystals with modulated structure(periodic lamina of ferroelectric domains)is first presented.The alternation of the ferroelectric domains whose half-pe...A radio-frequency heating Czochralski technique to obtain LiTaO3 crystals with modulated structure(periodic lamina of ferroelectric domains)is first presented.The alternation of the ferroelectric domains whose half-period nearly corresponds to the coherence length LC has been achieved.Quasi-phase-matching for the nonlinear coefficient d_(33) has been first realized using 1.06μm Nd:YAG laser in crystals LiTnO_(3).展开更多
Detection of abnormal myocardial perfusion is crucial to the prognosis of patients with coronary artery disease(CAD)after they have undergone percutaneous coronary intervention(PCI).The objective of this study is to e...Detection of abnormal myocardial perfusion is crucial to the prognosis of patients with coronary artery disease(CAD)after they have undergone percutaneous coronary intervention(PCI).The objective of this study is to evaluate the effect of myocardial perfusion by three different methods—intra-coronary myocardial contrast echocardiography(ICMCE),corrected thrombolysis in myocardial infarction frame count(CTFC),and coronary blood flow velocity(BFV)—and to determine the value of these different methods in the evaluation of the effect of myocardial perfusion post-PCI.For the study sixty-eight patients were divided into four groups based on selective coronary angiography results:group A(normal coronary artery),group B(75%–95%coronary artery stenosis),group C(coronary artery stenosis>95%)and group D(acute total coronary occlusion).The effect of myocardial reperfusion was evaluated using the above mentioned three methods 15 min after PCI.IC-MCE was also performed before PCI in group D.The quantitative parameters of MCE involved:contrast peak intensity,time to peak intensity and area under the curve,representing myocardial blood volume,reperfusion velocity and myocardial blood flow,respectively.No difference was found in CTFC between the coronary artery stenosis group and the normal group.BFV was slower in group D than in group A(P<0.05).The myocardial blood volume and the myocardial blood flow of the IC-MCE quantitative parameters were markedly lower in group C compared with those in group A(P<0.05),and there were significant differences in the three MCE parameters between group D and group A(P<0.05).For those patients with acute or total occlusion,the levels of myocardial perfusion before and after PCI were similar,as determined by IC-MCE and visually analyzed from 61 segments(P<0.05).Quantitative IC-MCE evaluation of myocardial reperfusion is more accurate than with the other two methods.Moreover,with qualitative IC-MCE the level of myocardial reperfusion can be viewed directly and rapidly.Thus,the IC-MCE method is of great value to coronary artery disease(CAD)patients undergoing PCI,especially for those with acute myocardial infarction(AMI).展开更多
文摘A radio-frequency heating Czochralski technique to obtain LiTaO3 crystals with modulated structure(periodic lamina of ferroelectric domains)is first presented.The alternation of the ferroelectric domains whose half-period nearly corresponds to the coherence length LC has been achieved.Quasi-phase-matching for the nonlinear coefficient d_(33) has been first realized using 1.06μm Nd:YAG laser in crystals LiTnO_(3).
文摘Detection of abnormal myocardial perfusion is crucial to the prognosis of patients with coronary artery disease(CAD)after they have undergone percutaneous coronary intervention(PCI).The objective of this study is to evaluate the effect of myocardial perfusion by three different methods—intra-coronary myocardial contrast echocardiography(ICMCE),corrected thrombolysis in myocardial infarction frame count(CTFC),and coronary blood flow velocity(BFV)—and to determine the value of these different methods in the evaluation of the effect of myocardial perfusion post-PCI.For the study sixty-eight patients were divided into four groups based on selective coronary angiography results:group A(normal coronary artery),group B(75%–95%coronary artery stenosis),group C(coronary artery stenosis>95%)and group D(acute total coronary occlusion).The effect of myocardial reperfusion was evaluated using the above mentioned three methods 15 min after PCI.IC-MCE was also performed before PCI in group D.The quantitative parameters of MCE involved:contrast peak intensity,time to peak intensity and area under the curve,representing myocardial blood volume,reperfusion velocity and myocardial blood flow,respectively.No difference was found in CTFC between the coronary artery stenosis group and the normal group.BFV was slower in group D than in group A(P<0.05).The myocardial blood volume and the myocardial blood flow of the IC-MCE quantitative parameters were markedly lower in group C compared with those in group A(P<0.05),and there were significant differences in the three MCE parameters between group D and group A(P<0.05).For those patients with acute or total occlusion,the levels of myocardial perfusion before and after PCI were similar,as determined by IC-MCE and visually analyzed from 61 segments(P<0.05).Quantitative IC-MCE evaluation of myocardial reperfusion is more accurate than with the other two methods.Moreover,with qualitative IC-MCE the level of myocardial reperfusion can be viewed directly and rapidly.Thus,the IC-MCE method is of great value to coronary artery disease(CAD)patients undergoing PCI,especially for those with acute myocardial infarction(AMI).
