激光辐照转动充压圆柱壳体热力学效应

 采用有限元计算方法对激光辐照下转动充压壳体的热力学问题进行了较为全面的数值计算，获得了激光辐照下转动内压圆柱壳壁上的温升、应力、应变、位移分布等物理图像，为进一步分析转动充压圆柱壳体在激光辐照下的破坏与失效奠定了基础。提出的解决数值计算中移动热流载荷问题的双时间步长法，可以有效提高计算效率，同时提高计算精度。研究结果表明：对于给定的壳体结构，其损伤阈值时间主要取决于靶面激光强度与壳体旋转频率；在辐照过程中，损伤最先出现在最初受激光辐照的区域。     

激光辐照下充压柱壳的破坏能量阈值数值模拟

采用有限元方法模拟了激光辐照下充压柱壳的热力学响应,计算了不同工况下结构的瞬态温度场和应力场,根据材料强度准则判断了柱壳的破坏时刻,并提出了一种预测激光辐照下充压柱壳破坏能量阈值的数值方法。研究了壳体厚度和内压大小对柱壳破坏能量阈值的影响,并给出了典型工况下柱壳破坏能量阈值同壳体厚度以及充压大小的关系。数值计算结果表明：破坏能量密度阈值与壳体厚度、内压大小近似成线性关系,壳体厚度比内压大小对柱壳的激光破坏能量阈值影响更大。     

激光辐照下充压柱壳的破坏能量阈值数值模拟

采用有限元方法模拟了激光辐照下充压柱壳的热力学响应,计算了不同工况下结构的瞬态温度场和应力场,根据材料强度准则判断了柱壳的破坏时刻,并提出了一种预测激光辐照下充压柱壳破坏能量阈值的数值方法。研究了壳体厚度和内压大小对柱壳破坏能量阈值的影响,并给出了典型工况下柱壳破坏能量阈值同壳体厚度以及充压大小的关系。数值计算结果表明:破坏能量密度阈值与壳体厚度、内压大小近似成线性关系,壳体厚度比内压大小对柱壳的激光破坏能量阈值影响更大。     

激光诱导充压柱壳破坏模式与参数阈值分析

通过数值计算模拟了激光诱导充压柱壳的热力破坏效应,研究了典型结构的动态爆裂过程,获得的破坏模式与实验结果基本一致。给出了三类典型破坏模式及其对应的参数范围,探讨了各类破坏模式的形成机理,并分析了不同光斑尺寸、壳体厚度条件下热软化效应对破坏内压阈值的影响,以及预内压与破坏时间的关系。研究结果表明:光斑半径越大、热软化程度越高,柱壳的破坏内压阈值越低,且破坏内压阈值随着壳体厚度的减小呈线性下降;给定激光参数和壳体参数下破坏时间随预充内压增大而减小并呈二次函数关系。给出了一种通过热软化程度预估激光诱导充压柱壳破坏时间的方法。     

激光辐照下旋转柱壳温度场的数值模拟

采用有限元方法数值模拟在连续激光辐照下旋转柱壳温度场的变化和分布情况,并分析了热性能参数对温度场造成的影响,同时还比较分析了不同旋转频率对柱壳温度场分布的影响。结果表明,激光作用下旋转柱壳的温升大大低于静止柱壳的温升, 外表面温度呈现出与旋转频率相符的周期性上升过程,而内表面温升由于热传导的原因在较小频率下才表现出这种周期性,当频率增大到一定值时,内表面温升不出现周期性的台阶而是曲线上升。     

强激光辐照下预载柱壳热屈曲失效的数值分析

 采用有限元方法（ANSYS7.0）和简易的热力耦合本构关系,较系统地数值研究了预载柱壳受激光辐照时的热力响应和热屈曲失效行为,分析了几种壳体在不同预载条件下（轴压或内压）的屈曲模态和屈曲特征值,给出了屈曲模态和热屈曲失效与激光强度、辐照时间、预载条件和壳体几何尺度及形状间的定量或定性关系。计算结果表明：（1）屈曲失效行为主要集中在激光辐照区内且以径向屈曲为主。（2）在一定范围内,屈曲特征值与光斑中心点温度近似有线性关系。（3）激光辐照区内高温引起的材料软化和预载径向变形的耦合作用是柱壳发生热屈曲失效的根本原因,有效提高结构刚度,可使屈曲特征值提高。（4）壳体形状的改变对内压柱壳有更为明显的影响,其中圆柱形壳体屈曲特征值最大,因此具有较高的安全性。     

强激光对星载光电探测系统的干扰与破坏研究

建立了激光辐照星载光电探测器的数学模型,对激光干扰和破坏星载光电系统的机理进行了研究,分析了激光光束与探测器光轴的偏角对干扰和破坏的影响.以CO2激光辐照HgCdTe探测器的实例,研究了强激光对探测单元的破坏,得到其损伤阈值曲线,并从理论上证明了强激光对星载光电探测系统干扰和破坏的可行性.     

强激光辐照下柱壳温度场的数值模拟

 用有限元方法数值模拟强激光辐照下柱壳上温度场的变化和分布情况，并对热性能参数随温度变化对温度场造成的影响进行了研究。     

激光辐照下旋转柱壳温度场的数值模拟

 采用有限元方法数值模拟在连续激光辐照下旋转柱壳温度场的变化和分布情况,并分析了热性能参数对温度场造成的影响,同时还比较分析了不同旋转频率对柱壳温度场分布的影响。结果表明,激光作用下旋转柱壳的温升大大低于静止柱壳的温升, 外表面温度呈现出与旋转频率相符的周期性上升过程,而内表面温升由于热传导的原因在较小频率下才表现出这种周期性,当频率增大到一定值时,内表面温升不出现周期性的台阶而是曲线上升。     

内表面掺硅聚苯乙烯空心微球初步研究

靶丸内表面掺杂诊断元素可以为内爆压缩界面的研究提供必要的手段。以二甲基二乙氧基硅烷为原料，利用乳液微封装技术和界面聚合技术可以实现单一内表面掺硅的空心聚苯乙烯微球的制备。X光照相和X能谱分析表明:内表面掺硅量比外表面高出2~3个数量级。均匀内表面掺硅层的厚度小于0.3μm，掺杂层厚度越小，均匀性越好。     

激光辐照下静止及旋转充压柱壳结构变形的对比分析

 采用3维实体单元模拟激光辐照下静止及旋转充压柱壳的应力和应变分布,分析了柱壳可能发生破坏的位置和条件。通过对计算结果的分析表明,对于激光辐照下静止及旋转充压柱壳,裂纹都有可能在光斑边缘附近产生。但由于在旋转充压柱壳上,在过光斑中心圆周上有高应力带状区域,因此旋转柱壳有可能在这一环带区域也发生破坏。在相同的激光加载条件下,静止充压柱壳更容易在局部区域开始发生破坏。     

激光辐照下充压柱壳热断裂的可能性分析

采用3维实体单元来模拟激光辐照下充压柱壳的应力和应变分布,在光斑边缘采用棱锥单元来处理过渡区,分析了柱壳裂纹萌生的可能位置和条件。通过计算发现：外热源加载的柱壳在时间较短、内压足够大时,裂纹可能会在光斑边缘处产生并扩展开来;在功率相同的条件下,小光斑辐照时易产生裂纹,功率密度相同时,大光斑辐照下易产生裂纹,说明柱壳破坏的一个因素取决于功率密度;柱壳在不同时间,应力与抗拉强度之比分布不同,过光斑中心的柱壳母线上的环向应力在柱壳裂纹的萌生中起主要作用。     

Inclusion of temperature dependent shell corrections in Landau theory for hot rotating nuclei

Landau theory used for studying hot rotating nuclei usually uses zero temperature Strutinsky smoothed total energy for the temperature dependent shell corrections. This is replaced in this work by the temperature dependent Strutinsky smoothed free energy. Our results show that this replacement has only marginal effect for temperatures greater than 1 MeV but plays significant role at lower temperatures.     

The measurement of 3-D asymmetric temperature field by using real time laser interferometric tomography

A real time nondestructive temperature measurement technique based on laser holographic interference tomography technique is presented. An He–Ne laser is used as light source, and a CCD video camera is used to grab the interferogram. This laser holographic tomography technique is applied to the measurement of the temperature fields generated by two heated rods. Since data error is inevitable in engineering measurement, it is necessary to study the reconstruction techniques for reconstructing the temperature field. Three techniques including convolution back projection (CBP), algebra reconstruction technique (ART) and simultaneous iterative reconstruction technique (SIRT) are studied. Based on the reconstruction techniques and experimental situation, ART is used to reconstruct the asymmetric temperature fields. The thermocouples are used to measure the temperatures of the two heated rods. Comparing the reconstructed result with the measured temperature value, a satisfactory result is obtained.     

激光对红外系统的失效机理和破坏效应研究

 根据红外光学系统的会聚特性，用光学增益方法分析了红外系统中各元件对应的光强分布，确定了位于焦面附近光学元件是激光破坏的易损部件，并提出了强激光对红外系统元件损伤,造成其探测、制导功能失效的硬破坏机理；由红外滤光片、探测器和信号处理电路与入射激光波长的光谱响应分析，提出了弱激光对红外系统干扰，导致其探测、制导功能在激光辐照一段时间内失效的软破坏机理；开展了激光辐照红外系统的失效验证实验，较好地解释了其失效的机理和效应。     

Evaluation of nuclear shell correction energies for realistic level schemes by temperature smearing method

Calculations of shell correction energies by the temperature smearing method for realistic single particle level schemes of finite depth potentials are described and discussed. It is found that the method provides unique values of the shell correction energies for the various shapes relevant in the fission of actinide nuclei including those shapes where breakdown of the usual Gaussian energy smearing procedure was observed.     

Elastic characterization of platinum/rhodium alloy at high temperature by combined laser heating and laser ultrasonic techniques

We demonstrate an innovative pump–probe technique combined with laser heating to determine the velocity of a surface Rayleigh wave at high temperature. Laser ultrasonics in a point-source–point-receiver configuration was combined with laser heating to evaluate the elastic properties of micron size specimens. The measurements of the velocity of the surface Rayleigh wave (SRW) were conducted at 1070 K.     

Identification and qualification of temperature signal for monitoring and control in laser cladding

Laser cladding has been successfully introduced into industry for the use in wear and corrosion applications and in the repair work such as turbine components, moulds and dies. Through monitoring and furthermore controling the cladding process, the quality and reproducibility in the production can be ensured. Thus the economic efficiency can increase through the reduced scrap rate. The aim of this work is to identify and analyse the infrared temperature signal emitted from the melt pool, which could be used for quality control and for closed loop control. Different measure systems including a photodiode, pyrometer and CCD camera with different functional wavelengths were used to detect the temperature radiation. The detected signals show dependence on the main process parameters including laser power, powder feeding rate and scanning speed. The results of the clad such as dilution and dimension have very good correlation with the measured temperature signal. A process monitoring and control system based on the infrared temperature signal with coaxial alignment of the ancillary lenses was established and tested successfully.