基于拓扑优化的压电分流阻尼抑振实验研究

将结构拓扑优化引入压电分流振动抑制中,以压电元件的分布面积为设计变量,压电元件产生的电荷最大化为优化目标,对压电元件的拓扑进行了优化以获得最佳抑振效果。针对悬臂梁结构,得到了对不同的结构模态进行抑制时的压电元件最优拓扑构型。建立了带有压电分流阻尼系统的悬臂梁振动控制实验模型,将压电元件拓扑优化后的压电分流阻尼系统应用于悬臂梁多阶弯曲模态的振动响应抑制实验,并对比分析了带最优拓扑和非优拓扑压电元件的悬臂梁压电分流阻尼抑振效果。结果表明,对压电元件进行拓扑优化可以明显提高压电分流阻尼系统的抑振效果。     

深浮雕连续微光学元件制作方法

提出一种连续深浮雕微光学元件的制作方法。在移动掩模的基础上经湿法显影获得光刻胶元件良好的面形,然后结合干法刻蚀刻将图形通过蚀速比放大的办法精密传递到石英片基上,从而使最终的元件达到设计的浮雕度。作者对整个过程进行了考察和讨论,并以微棱镜为进行了实验验证中心为进一步制作大数值孔微光学元件打下了技术基础。     

组件设计对卷式反渗透膜元件抗污染性及能耗影响

选择在螺旋卷式反渗透膜元件组件设计中,对影响膜元件使用寿命的抗污染性能及影响膜元件系统运行能耗的工艺参数进行理论模拟实验,并与实际生产运行相结合,得出最优化的设计组合.主要工艺参数为给水流道布宽度、深度、入水角度、及膜元件卷制页数的优化选择,筛选出提高抗污染性能及低能耗、高经济性的膜元件,并对螺旋卷式膜元件的设计起指导作用.     

增透膜应用领域涉及医学军事太空探索

正由于元件表面的反射作用而使光能损失,为了减少元件表面的反射损失,常在光学元件表面镀层透明介质薄膜,这种薄膜就叫增透膜。可以分别从能量守恒的角度对增透膜增加透射的原理给予定性分析;根据菲涅尔公式和折射定律对增透膜增加透射的原理给予定量解释;利用电动力学的电磁理论对增透膜增加透射的原理给予理论解释。     

两结构联系振动控制体系及控制元件参数优化

本文提出了两结构依靠控制元件（弹性及阻尼元件）联系组成的两结构联系振动控制体系。给出了控制元件在两结构间优化布置的设计方法及控制元件参数（弹簧刚度、阻尼元件阻尼值）的优化设计方法。应用本文的方法，对两结构联系振动控制系统进行优化设计，得到经济的优化设计方案。     

基于粒子群优化算法的控制面板布局优化方法研究

针对目前核电站主控制室后备盘台人机界面设计过多依赖人的经验和主观判断从而导致控制面板布局随意性的问题,提出了基于粒子群优化算法的控制面板布局设计优化方法,即先对控制面板上元件的重要性、操作频率、操作顺序和相关性等工效学布局原则分别进行数学描述,并依此构造布局优化目标函数,将布局问题抽象为数学问题,然后采用粒子群优化算法对布局优化目标函数进行求解,以便快速地找到最优布局方案,从而达到布局优化的目的.通过对16个操纵和显示元件进行布局优化计算,证明了该方法能有效地解决后备盘台人机界面布局优化问题.     

深紫外宽入射角范围增透膜设计与制备

在大数值孔径深紫外光学系统中,需要使用宽入射角范围的增透膜光学元件.选择LaF3和MgF2两种镀膜材料,设计了适用于深紫外宽入射角范围的三层、五层和七层三种增透膜系.实验使用热舟蒸发在熔融石英基底上镀制了设计的薄膜,并用紫外分光光度计对其光谱性能进行了测试,得到了在宽入射角范围内具有较高透过率的深紫外增透膜元件.双面镀五层增透膜系的熔石英基片在0°～55°入射角内的剩余反射率小于2.5％,在0°～20°入射角内的透过率大于98％.     

遗传算法用于衍射光学元件的优化设计

提出了一种基于遗传算法的衍射光学元件优化设计方法;在衍射光学元件设计中遗传算法运行参数对遗传算法性能有一定的影响:采用较大的群体规模,遗传算法越容易获得最优解;交叉算子越大,遗传算法全局搜索能力越强;选择算子对遗传算法的影响不是太大;如果要进一步提高解的精度,可选取较大的终止代数。数值计算结果表明,用遗传算法优化设计的衍射光学元件,其误差小于 5.2%,衍射效率达到 91.2%。遗传算法很适合衍射光学元件的优化设计。     

基于动力学模型与参数优化的ISD悬架结构设计及性能分析

为寻找结构简单、性能优越的悬架结构(Inerter-Spring-Damper,ISD),对储能元件、支撑元件及耗能元件按不同位置构建21种工程上可行的拓扑结构,建立通用动力学模型。以簧上质量加速度及轮胎动载为目标进行优化,获得每种结构的元件参数。与传统悬架对比发现有12种新型结构性能优于传统悬架。对典型结构分析表明,动力学建模与参数优化方法在ISD悬架设计中具有一般性、通用性。     

误差扩散法编码设计制作微光学元件

以发展微光学元件制作新方法为目标,提出利用误差扩散编码方法设计灰阶编码掩模制作微光学元件。此方法同其他编码方法相比,具有量化效果好、衍射效率高、制作文件小、计算速度快、通用性好等优点。用此方法对制作微透镜的掩模进行了设计,利用预校正法和边缘增强法相结合的方法对掩模进行了优化,并对曝光、显影过程进行了模拟,得到了满意的结果。     

Rigorous electromagnetic analysis of the common focusing characteristics of a cylindrical microlens with long focal depth and under multiwavelength illumination

The common focusing characteristics of a cylindrical microlens with a long focal depth and under a given multiple-wavelength illumination are analyzed based on the boundary element method (BEM). The surface-relief profile of a finite-substrate-thickness microlens with a long focal depth is presented. Its focusing performances, such as the common extended focal depth (CEFD), the spot size, and the diffraction efficiency, are numerically studied in the case of TE polarization. The results show that the CEFD of the microlens increases initially, reaches a peak value, and then decreases with increasing preset focal depth. Two modified profiles of a finite-substrate-thickness cylindrical microlens are proposed for enlarging the CEFD. The rigorous numerical results indicate that the modified surface-relief structures of a cylindrical microlens can successfully modulate the optical field distribution to achieve longer CEFD, higher transverse resolution, and higher diffraction efficiency simultaneously, compared with the prototypical microlens. These investigations may provide useful information for the design and application of micro-optical elements in various multiwavelength optical systems.     

Design of microlenses with long focal depth based on the general focal length function

A general focal length function is proposed to design microlenses with long extended focal depth and high lateral resolution. The focal performance of the designed microlenses, including the actual focal depth, the focal spot size, and the diffraction efficiency, is calculated by rigorous electromagnetic theory and the boundary-element method for several f-numbers. In contrast to conventional microlenses, the numerical results indicate that the designed microlenses can exhibit long extended focal depth and good focal performance. It is expected that the long focal length function will be widely used to design microlenses with long focal depth characteristics.     

Analysis of a cylindrical microlens array with long focal depth by a rigorous boundary-element method and scalar approximations

We investigated the focal characteristics of open-regional cylindrical microlens arrays with long focal depth by using a rigorous boundary-element method (BEM) and three scalar methods, i.e., a Kirchhoff and two Rayleigh-Sommerfeld diffraction integral forms. Numerical analysis clearly shows that the model cylindrical microlens arrays with different f-numbers can generate focusing beams with both long focal depth and high transverse resolution. The performance of the cylindrical microlens arrays, such as extended focal depth, relative extended focal depth, diffraction efficiency, and focal spot size, is appraised and analyzed. From a comparison of the results obtained by the rigorous BEM and by scalar approximations, we found that the results are quite similar when the f-number equals f/1.6; however, they are quite different for f/0.8. We conclude that the BEM should be adopted to analyze the performance of a microlens array system whose f-number is less than f/1.0.     

A 100-MHz ultrasound imaging system for dermatologic and ophthalmologic diagnostics

A major design problem concerning high-frequency broad-band ultrasound imaging systems is caused by the strong dispersive attenuation of the tissue, which gives rise to images with inhomogeneous resolution and poor signal to noise ratio (SNR). To address the noise problem, strongly focused transducers with high energy density in a narrow focal region are utilized, which also provide more isotropic images due to improved lateral resolution. To account for the short depth of the focal area two suitable imaging conceptions are used: 1) synthetic aperture concept and 2) B/D-scan concept. To avoid the inhomogeneity of the images, different transmitter signals for each depth are applied, which are pseudoinversely prefiltered according to the transfer function of the tissue. To gain signal energy required for inverse filtering, a pulse compression technique with nonlinearly frequency modulated chirp signals is utilized. These procedures have been implemented in an ultrasound imaging system, which has been developed in the authors' laboratory for eye and skin examinations, It can be used with transducers in a frequency range from 20 to 250 MHz.     

Rigorous electromagnetic analysis of a microcylindrical axilens with long focal depth and high transverse resolution.

We first present nonparaxial designs for a microcylindrical axilens with different long focal depths and rigorously analyze electromagnetic field distributions of the axilens using integral equations and the boundary-element method. Numerical results show that the designed axilenses indeed have the special feature of attaining a long focal depth while keeping high transverse resolution for numerical apertures of 2.4, 2.0, and 1.0. The ratio between the extended focal depth of the designed axilens and the focal depth of the conventional focal lens is 1.41, the corresponding maximal extended focal depth of the axilens can reach 28 microm, and the spot size of the focal beam is approximately 10 microm over the focal range.     

Construction and performance of a multiparameter focal plane detector for use on a QMG/2 magnetic spectrometer

The design, construction and performance of a modular, two pressure focal plane detector, 550 mm long, 1000 mm deep and with an active height of 60 mm are described. The detector has been operated with ions ranging from 50 MeV ¹H to 200 MeV ³⁶S. Typical results achieved are 0.5 mm and 0.3° for the spatial and angular resolutions, and 0.7% and 3% for the total energy and energy loss measurements. A height signal is also provided.     

Energy integrals for the systems with nonholonomic constraints of arbitrary form and origin

This work analyzes energy relations between nonholonomic systems, whose motion is restricted by nonholonomic constraints of arbitrary form and origin. Such constraints can be natural, originating from spontaneous formulation of the problem, or artificial, expressing some program motion in control theory. On the basis of corresponding Lagrange’s equations, a general law of the change in energy d?/dt was formulated for such systems by the help of which it has been shown that here there exist two types of laws of conservation of energy, depending on the structure of work of these reaction forces. Also, the condition for existence of this second type of the law of conservation of energy has been formulated in the form of the system of differential equations. The results obtained are illustrated by a number of examples, with natural nonlinear constraints, as well as with artificial ones that express some program motion.     

能量守恒定律在制冷循环过程中的解析

能量守恒定律是自然界普遍存在的定律之一,本文通过内能概念,利用能量守恒定律从微观上解释蒸气压缩式制冷的各个过程,从而为我们理解蒸气压缩式制冷原理提供了一个新思路。     

分形方法导出改进的牛顿第二定律及万有引力定律

牛顿第二定律及万有引力定律是根据实验结果总结出来的。为了探讨从理论上导出这两个定律的可能性，根据能量守恒定律，给出用变维分形方法针对一个实例（小球沿长斜面滚下）导出改进的牛顿第二定律及万有引力定律的方法。具体给出了适用于实例的常维分形结果：改进的万有引力定律F=-GMm / r199989和改进的牛顿第二定律F=ma101458。     

The realization of long focal depth with a linear varied-area zone plate

We report a linear varied-area zone plate, in which arbitrary long focal depth can be achieved by properly adjusting the corresponding parameters. Meanwhile, the lateral focal spot and side lobes can be kept very small. Numeral simulations are carried out to verify the performance of our zone plate through Fresnel–Kirchhoff diffraction theory, and the results are in good accord with the experimental verifications. The influences of our zone plate’s parameters to the intensity distribution in focal region are discussed in detail. Comparisons are made with the behaviour of a linear varied-line-space grating, and we find that the behaviour of our novel zone plate along optical axis is just like a reverse transformation of the focusing behaviour of a linear varied-line-space grating.