Jet formation in shock-heavy gas bubble interaction

The influences of the acoustic impedance and shock strength on the jet formation in shock-heavy gas bubble interaction are numerically studied in this work. The process of a shock interacting with a krypton or a SF6 bubble is studied by the numerical method VAS2D. As a validation, the experiments of a SF6 bubble accelerated by a planar shock were performed. The results indicate that, due to the mismatch of acoustic impedance, the way of jet formation in heavy gas bubble with different species is diversified under the same initial condition. With respect to the same bubble, the manner of jet formation is also distinctly different under different shock strengths. The disparities of the acoustic impedance result in different effects of shock focusing in the bubble, and different behaviors of shock wave inside and outside the bubble. The analyses of the wave pattern and the pressure variation indicate that the jet formation is closely associated with the pressure perturbation. Moreover, the analy- sis of the vorticity deposition, and comparisons of circulation and baroclinic torque show that the baroclinic vorticity also contributes to the jet formation. It is concluded that the pres- sure perturbation and baroclinic vorticity deposition are the two dominant factors for the jet formation in shock-heavy gas bubble interaction.

Experimental investigation on flow modes of electrospinning

Electrospinning experiments are performed by using a set of experimental apparatus, a stroboscopic system is adopted for capturing instantaneous images of the cone- jet configuration. The cone and the jet of aqueous solutions of polyethylene oxide （PEO） are formed from an orifice of a capillary tube under the electric field. The viscoelastic con- stitutive relationship of the PEO solution is measured and discussed. The phenomena owing to the jet instability are described, five flow modes and corresponding structures are obtained with variations of the fluid flow rate Q, the electric potential U and the distance h from the orifice of the cap- illary tube to the collector. The flow modes of the cone-jet configuration involves the steady bending mode, the rotat- ing bending mode, the swinging rotating mode, the blurring bending mode and the branching mode. Regimes in the Q-U plane of the flow modes are also obtained. These results may provide the fundamentals to predict the operating conditions expected in practical applications.

Nonlinear dynamics and manipulation of dripping in capillary flow focusing

In this study, we carried out experimental and numerical investigations on the dripping dynamics in axisymmetric capillary flow focusing. For the direct numerical simulations, we solved the Navier-Stokes equations coupled with a diffuse interface method.For the experiments, we observed both periodic and non-periodic dripping modes at different focused and focusing liquid flow rates. The non-periodic dripping that results in polydispersed droplets downstream the orifice can be attributed to the nonlinear dynamics of the flow;thus, we constructed numerical plots of the streamlines and temporal evolutions of the focused liquid cone in different modes. We identified a phase diagram of the dripping regimes in the plane of mainly dimensionless parameters, which led us to further investigate the effects of liquid physical properties, such as viscosity and interface tension, on the mode transition.For suppression of the nonlinear dynamics, we proposed a geometrical optimization that imports a guiding rod positioning along the axis of the capillary tube. Here, we conducted a numerical analysis on the manipulation of the dripping process, as well as scaling analysis on the appearance of the nonlinear dripping. We expect this study to provide an insight into the underlying physical mechanisms of dripping in flow focusing, which are advantageous in the generation of monodispersed microdroplets for various applications.

自体造血干细胞移植治疗微小残留病阴性患者中危急性髓系白血病的影响因素分析

探讨影响自体造血干细胞移植(auto-HSCT)对于微小残留病阴性(MRD<0.1%, MRD-)中危急性髓系白血病(AML)预后的因素。对2015年1月至2021年9月在宁波大学附属人民医院接受auto-HSCT的59例MRD-中危AML患者进行回顾性分析, 收集一般资料、实验室及辅助检查结果等病例基本资料, 分析临床疗效、预后及其影响因素。应用Kaplan-Meier法进行生存分析, log-rank检验进行单因素分析, Cox比例风险回归模型进行多因素分析。59例MRD-中危AML患者中, 男性27例、女性32例, 中位年龄55(31~69)岁。所有患者中位随访时间761(317~1 861)d, 2年总生存(OS)率、无事件生存(EFS)率分别为76.1%±11.4%、73.4%±11.6%。单因素分析结果显示年龄>50岁、TET2基因突变(TET2^(+))、MRD转阴时间>30 d(MRD^(30+))是影响患者OS的危险因素(χ^(2)值分别为6.20、33.20、7.18, P值分别为0.013、<0.001、0.007), TET2^(+)、WT1基因突变(WT1^(+))、输注CD34^(+)细胞<2×106/kg、MRD^(30+)是影响患者EFS的危险因素(χ^(2)值分别为17.29、4.47、3.94、9.39, P值分别为<0.001、0.035、0.047、0.002)。多因素分析结果显示MRD^(30+)、TET2^(+)是影响接受auto-HSCT的MRD-中危AML患者OS及EFS的独立危险因素(OS:HR分别为9.251、25.839, P值分别为0.036、0.001;EFS:HR分别为5.851、9.199, P值分别为0.043、0.002)。MRD^(30+)、TET2^(+)是影响接受auto-HSCT的MRD-中危AML患者OS及EFS的独立危险因素, MRD^(30+)、TET2^(+)患者预后差, auto-HSCT后生存率低, 需要进一步探索有效的治疗方案。