CTA在急性复杂性大咯血患者行介入栓塞术前的应用价值分析

本文探讨了CT血管造影(CT angiography,CTA)在急性复杂性大咯血患者行介入栓塞术前的应用价值。回顾性选择49例急性复杂性大咯血患者CTA影像资料,通过与术中数字减影血管造影(digital subtraction angiography,DSA)结果进行对比,发现CTA对罪犯血管诊断准确率为89.33%,对多动脉交通吻合诊断准确率为86.96%。Kappa检验CTA与DSA检查结果一致性较高,受试者特征曲线(ROC)分析CTA诊断急性复杂性大咯血罪犯血管的曲线下面积(AUC)为0.947(95%CI:0.903~0.990,P=0.000),灵敏度89.33%,特异度100.00%。通过随访发现CTA指导下行介入栓塞术治疗有效率91.84%,术后1年无大咯血复发病例。     

燃爆冲击作用下岩石初始破坏区形成机制与主控因素

为揭示燃爆冲击作用下井周岩石破坏区的形成机制,并分析影响初始破坏区(破碎区和初始裂隙区)的主控因素,开展了两种岩样在不同加载速率下的冲击破坏实验, 分析了岩石冲击破坏模式及岩石对加载速率的响应, 借助基于Von Mise准则建立的岩石冲击破坏的破碎区和初始裂隙区计算模型可知:加载速率低于190 GPa/s时,可依据冲击峰值压力引导的应力分布确定破碎区和初始裂隙区作用范围;燃爆压裂在近井地带主要产生破碎区和裂隙区,破碎区直径为井眼直径的1~3倍,初始裂隙区直径为井眼直径的5~7倍;冲击载荷作用下,初始破坏区与加载速率、脆性指数呈正相关,且受脆性指数影响更显著。研究结果可提高对燃爆压裂过程中岩石的破坏模式及其主控因素的认识深度,为燃爆压裂冲击条件设计提供指导。     

强外电场作用下BN分子的结构与激发特性

采用密度泛函理论的B3LYP方法在6-311++g(d.p)水平上优化得到了BN分子轴向加不同外电场时的基态结构参数,包括键长、电偶极矩、电荷分布、前线轨道、红外光谱.计算结果表明,随着正向电场增加,分子结构参数与外电场强度有明显关联,并呈现不对称性.另外,在同样的基组下利用合时密度泛函理论方法研究了外电场对BN分子激发能和振子强度的影响.结果表明,电子跃迁光谱随正向电压的增加而呈现蓝移现象,但振子的强度与电场关联较为复杂,说明光谱强度易受外电场影响.     

Nonlinear Excitation and State Transition of Multi-Peak Solitons

We study the nonlinear excitations in the integrable fifth-order nonlinear Schr?dinger equation on a continuous wave background. The excited condition of each localized wave is demonstrated via concise phase diagrams.In particular, the rule of transition between asymmetric and symmetric multi-peak solitons is revealed. It is shown that the initial phase modulation can induce the transition and the transition condition is demonstrated exactly. Interestingly, our result shows that although the multi-peak solitons exhibit structural diversity, both the asymmetric and symmetric states possess an identical asymmetric spectrum structure.     

Controllable optical superregular breathers in the femtosecond regime

We investigate optical superregular breathers in the femtosecond regime under dispersion management in an inhomogeneous fiber governed by the nonautonomous higher-order nonlinear Schr o¨dinger equation(NLSE). Exact solutions describing the dynamics of superregular breathers are obtained. Furthermore, we discuss the propagation behaviors of controllable superregular breathers, including stabilization and recurrence in an exponential dispersion fiber and a periodic distributed fiber system. Particularly, the nonlinear dynamics of superregular modes evolved from an identical initial small-amplitude modulation is analyzed in detail.