缅怀声学泰斗魏荣爵先生——纪念魏荣爵先生诞辰一百周年

正2016年9月4日是我国声学泰斗魏荣爵先生诞辰一百周年,《声学学报》特发专辑以纪念和表彰魏荣爵先生为发展我国声学教育和科研事业所作出的杰出贡献,这表达了我们广大声学工作者共同的心声。作为魏先生的学生,积极响应为专刊撰写论文,介绍先生生前感兴趣领域最近所取得的进展和动态,告慰先生在     

大肠癌与微量元素研究

对48例大肠癌患者手术前后血清和正常大肠组织与癌组织中微量元素测定、比较，发现大脑癌患者手术前后血清微量元素变化，除Cr、Mn有显著差异外均无显著差异，而癌瘤组织与正常大脑组织中Ca、Cd、Mn、Zn、Cu/Zn有明显差异，探讨了大肠癌发生的机理。大肠癌病因是复杂的，但与微量元素改变有一定关系，并指出，组织测定观察微量元素变化比血清测定观察更敏感。     

Single—Bubble Sonoluminescence Under Different Driving Pressures

We experimentally investigate the single-bubble sonoluminescence(SBSL)under different driving pressures.The spectrum of SBSL,pulse shape of light emission and the SBSL phase that is compared with a sinusoidal driving pressure are all studied.The results show that the temperature and the width of the light pulse increase with increasing sound pressure.So does the phase of SBSL emission,which agrees very well with the numerical calculation result.At the same time,a possible method of determining the value of sound pressure was discussed.     

双频激励液体表面斑图的Floquet分析

对双频参量激励下的大宽高比容器中的粘滞液体表面起始斑图(Pattern)的动力学行为进行了理论研究.通过计算可给出形成斑图的最低激励加速度阈值曲线、斑图的响应模式及其频率谱等.同时,还讨论了双频激励的斑图双临界现象.所有结果均在无任何可调参量的前提下,与Edwards等的实验结果定量一致. 关键词：     

In vivo hyperthermia effect induced by high-intensity pulsed ultrasound

Hyperthermia effects (39-44°C) induced by pulsed high-intensity focused ultrasound (HIFU) have been regarded as a promising therapeutic tool for boosting immune responses or enhancing drug delivery into a solid tumor. However, previous studies also reported that the cell death occurs when cells are maintained at 43°C for more than 20 minutes. The aim of this study is to investigate thermal responses inside in vivo rabbit auricular veins exposed to pulsed HIFU (1.17 MHz, 5300 W/cm2 , with relatively low-duty ratios (0.2%-4.3%). The results show that: (1) with constant pulse repetition frequency (PRF) (e.g., 1 Hz), the thermal responses inside the vessel will increase with the increasing duty ratio; (2) a temperature elevation to 43°C can be identified at the duty ratio of 4.3%; (3) with constant duty ratios, the change of PRF will not significantly affect the temperature measurement in the vessel; (4) as the duty ratios lower than 4.3%, the presence of microbubbles will not significantly enhance the thermal responses in the vessel, but will facilitate HIFU-induced inertial cavitation events.     

基于非线性超传导的能流不对称传输现象的研究

研究了非线性传输线电路禁带内能量的不对称传输现象. 传输线电路中的两子电路结构相同,电感参数不同,并且具有低通滤波器的特点. 鉴于驱动频率在通频带的截止频率之上,所以形成不对称能流的载体为 禁带内传播的非线性波.该研究中,产生不对称能量传输的机理与非线性超传导现象密切相关. 通过调整耦合电感的大小,总结出传输能量与耦合强度之间的变化规律. 同时也采用仿真的方式分析了驱动电压幅值与传输能量间的相关性. 最后,通过在实验上改变驱动频率的大小,得到超传导发生时的门限电压与驱动频率间的依赖关系, 该关系与理论计算的结果完全定性一致.     

Computational simulation of ionization processes in single-bubble and multi-bubble sonoluminescence

The most recent spectroscopic studies of moving-single bubble sonoluminescence (MSBSL) and multi-bubble sonoluminescence (MBSL) have revealed that hydrated electrons (e$_{{\rm aq}}^{-}$) are generated in MSBSL but absent in MBSL. To explore the mechanism of this phenomenon, we numerically simulate the ionization processes in single- and multi-bubble sonoluminescence in aqueous solution of terbium chloride (TbCl$_{3}$). The results show that the maximum degree of ionization of single-bubble sonoluminescence (SBSL) is approximately 10000 times greater than that of MBSL under certain special physical parameters. The hydrated electrons (e$_{{{\rm aq}}}^{-}$) formed in SBSL are far more than those in MBSL provided these electrons are ejected from a bubble into a liquid. Therefore, the quenching of e$_{{{\rm aq}}}^{-}$ to SBSL spectrum is stronger than that of the MBSL spectrum. This may be the reason that the trivalent terbium [Tb(III)] ion line intensities from SBSL in the TbCl$_{3}$ aqueous solutions with the acceptor of e$_{{{\rm aq}}}^{-}$ are stronger than those of TbCl$_{3}$ aqueous solutions without the acceptor of e$_{{{\rm aq}}}^{-}$. Whereas the Tb(III) ion line intensities from MBSL are not variational, which is significant for exploring the mechanism behind the cavitation and sonoluminescence.     

Snapback-free shorted anode LIGBT with controlled anode barrier and resistance

A novel shorted anode lateral-insulated gate bipolar transistor(SA LIGBT)with snapback-free characteristic is proposed and investigated.The device features a controlled barrier V_barrierand resistance R_SAin anode,named CBR LIGBT.The electron barrier is formed by the P-float/N-buffer junction,while the anode resistance includes the polysilicon layer and N-float.At forward conduction stage,the V_barrierand R_SAcan be increased by adjusting the doping of the P-float and polysilicon layer,respectively,which can suppress the unipolar mode to eliminate the snapback.At turn-off stage,the low-resistance extraction path(N-buffer/P-float/polysilicon layer/N-float)can quickly extract the electrons in the N-drift,which can effectively accelerate the turn-off speed of the device.The simulation results show that at the same V_on of 1.3 V,the E_offof the CBR LIGBT is reduced by 85%,73%,and 59.6%compared with the SSA LIGBT,conventional LIGBT,and TSA LIGBT,respectively.Additionally,at the same Eoffof 1.5 m J/cm²,the CBR LIGBT achieves the lowest V_on of 1.1 V compared with the other LIGBTs.     

观测包膜微泡在超声场中的动力学行为

运用长距离显微成像系统与锁相积分拍摄技术相结合的方法, 拍到了单个造影剂微泡在两种不同频率和不同声压下的周期性振动图像. 根据这些图像得到了微泡直径的实验数据, 并分别用Hoff模型和Rayleigh-Plesset模型对数据进行拟合, 并对数据进行了频谱分析. 结果表明:Hoff模型对实验数据的拟合结果优于Rayleigh-Plesset模型的拟合结果; 二次谐波的相对强度随着声压幅度的升高而增大. 关键词： 包膜微泡 锁相积分拍摄方法 频谱