On Ground State Correlations in Nuclear Many-Body Systems

The ground state correlation in model systems with different interaction strength and pardcle numbers has been studied. Nunnerical results tell us that if the ground state shape is quite stable, the ground state correlation can be approximately explained by the zero-point vibration based on the stadc ground state. It is rather important to carry out first the static self consistent field calculation. But around the critical point where the monopole deformation begins to occur, behaviors of the ground state conflation become very complicate and sensitive to the variation of controlling parameters. lt seems to indicate that particular attentions should be paid to ground state compilations in further studies of light nuclei near the drip line.     

磁流体密封泄放压与外磁场变化关系的研究

根据实验室研制的磁流体密封装置，采用自制煤油基磁流体，通过多次实验初步探索到磁体泄放压与外磁场之间的变化规律。     

恶劣环境下高速数据存储的研究与实现

针对强震动、强冲击等恶劣环境的要求,应用FLASH固态存储器,开发了一种基于单片机控制的接口简单、重量轻、体积小的大容量数据存储系统在机载CCD相机的高速图像数据存储设计中,得到了很好的应用.     

强激光冲击铝合金改性处理研究

利用新型聚偏1.1-二氟乙烯（PVDF）压电传感器,实现了对激光引发的冲击波压力的实时测量,得到激光引发的冲击波峰压在铝中成指数型的衰减规律;观测了不同约束层材料在铝靶表面产生的激光冲击波,研究了不同约束层对冲击效果的影响;最后用激光冲击强化装置对7050-T7451航空铝合金结构材料进行了冲击强化处理,对试件激光冲击区存在的残余压应力及位错密度进行了测量。结果显示经激光冲击处理的试件表面具有极高的残余压应力,可达-200MPa以上。激光冲击处理后铝合金的位错密度得到显著的提高,疲劳寿命提高到175％～428％。这些重要结果对激光冲击改性处理技术的实际应用具有指导性作用。     

Fe掺杂CaCu3Ti4O12陶瓷的介电性能与弛豫特性研究

采用固相反应法制备了CaCu3Ti4-xFexO12(0≤x≤0.2)陶瓷,通过x射线衍射、扫描电子显微镜、介电频谱和阻抗谱等手段研究了Fe对CaCu3Ti4O12陶瓷的结构和介电性能的影响.研究发现:CaCu3Ti4-xFexO12陶瓷在x取值范围内形成了连续固溶体.随着Fe含量x的增加,晶粒半导性逐渐消失,介电常数减小.当x≤0.04时,在106-108和103-104 Hz频率范围存在介电弛豫行为I和介电弛豫行为Ⅱ,高频介电弛豫行为I与陶瓷内的晶界阻挡层有关,而低频介电弛豫行为Ⅱ与陶瓷表面层发生的界面极化有关.在CaCu3Ti3.99Fe0.01O12陶瓷的高温频谱中,观察到了第三个介电弛豫行为Ⅲ,它与局域电荷的跃迁有关,利用阿列纽斯关系式得到此过程的热激活能0.78 eV.     

Monte Carlo simulation of the dynamic evolution ofbinary lamellar eutectic in directional solidification

The dynamic evolution of the lamellar eutectic of binary alloys in directional solidification is studied in detail using the Monte Carlo technique. The simulated results can be summarized into two aspects: ({1}) the lamellar spacing λ is found to be inversely proportional to the chemical potential difference Δμ, predicting a linear relationship between the kinetic supercooling ΔT_k and total supercooling at the solid/liquid (S/L) interface; (2) as the solidifying velocity R is low, the dynamic product λ^{2}R shows a considerable dependence on temperature gradient G_T in the liquid in front of the S/L interface, although this dependence becomes much weaker at a high R.     

Low-frequency modulation of distortion product otoacoustic emissions in humans

Low-frequency modulation of distortion product otoacoustic emissions (DPOAEs) was measured from the human ears. In the frequency domain, increasing the bias tone level resulted in a suppression of the cubic difference tone (CDT) and an increase in the magnitudes of the modulation sidebands. Higher-frequency bias tones were more efficient in producing the suppression and modulation. Quasi-static modulation patterns were derived from measuring the CDT amplitude at the peaks and troughs of bias tones with various amplitudes. The asymmetric bell-shaped pattern resembled the absolute value of the third derivative of a nonlinear cochlear transducer function. Temporal modulation patterns were obtained from inverse FFT of the spectral contents around the DPOAE. The period modulation pattern, averaged over multiple bias tone cycles, showed two CDT peaks each correlated with the zero-crossings of the bias tone. The typical period modulation pattern varied and the two CDT peaks emerged with the reduction in bias tone level. The present study replicated the previous experimental results in gerbils. This noninvasive technique is capable of revealing the static position and dynamic motion of the cochlear partition. Moreover, the results of the present study suggest that this technique could potentially be applied in the differential diagnosis of cochlear pathologies.     

增量维纳滤波法在波前探测解卷积中的应用

一个常规的自适应光学系统通常包含三个重要环节：波前探测、波前校正和波前重构。因此对系统的技术要求非常高,造成系统复杂,成本昂贵。基于哈特曼-夏克波前探测的图像解卷积处理就是“事后”处理的一种,它省去了波前校正环节,使常规的自适应光学系统得到简化,降低了系统成本。其基本原理为对瞬时波面进行短时间曝光探测,同时记录相应的短时间曝光图像,来进行解卷积处理。将增量维纳滤波法应用于基于哈特曼-夏克波前探测的解卷积中,并对室内模拟点源情况下的三组畸变光斑图像数据进行了解卷积恢复处理。结果表明,将增量维纳滤波法应用于基于波前探测的解卷积是完全可行的,在室内模拟点源情况下,恢复的图像可以达到衍射极限分辨力。与维纳滤波相比,它扩展了噪声抑制因子的选取范围,在噪声抑制因子选取不正确的情况下,仍能得到比维纳滤波更好的结果。