应用理性优化蚁群算法提高激光三维复制的重现度

三维复制人工耳和打印手枪把激光三维复制技术推向新的一页。激光三维扫描是激光应用中一个新兴的重要领域,在三维复制中扮演着无可替代的角色,其复制精度在目前所有复制技术中是最高的。而重现度标志着复制结果与复制对象几何形状上的一致程度,是激光三维复制最重要的指标。分析了激光三维复制的误差,得出激光扫描的点云数据处理是减小误差、提高重现度的关键所在的结论。主要创新点在于,在传统蚁群算法的基础上,将提出理性优化蚁群算法应用于激光三维复制中的数据处理。经计算对比发现,有效减小了复制的误差,提高了复制的重现度。     

使用改进的形状优化方法设计高均匀度的超导MRI磁体

针对设计带铁磁的超导磁共振成像磁体,提出了一种确定类的优化算法来优化极靴的形状以达到匀场的目的。这种方法集合了灵敏度分析、形状优化的理论和有限元方法计算非线性铁磁材料极靴的配置,来改善两个极靴之间大体积成像区的磁场均匀度。需要指出的是,本优化方法不受极靴初始形状的限制,均可以快速收敛。我们通过一个紧凑型的1.2T双平面磁共振磁体,展示了这种方法。     

Optimization of highly nonlinear dispersion-flattened photonic crystal fiber for supercontinuum generation

A simple type of photonic crystal fiber (PCF) for supercontinuum generation is proposed for the first time. The proposed PCF is composed of a solid silica core and a cladding with square lattice uniform elliptical air holes, which offers not only a large nonlinear coefficient but also a high birefringence and low leakage losses. The PCF with nonlinear coefficient as large as 46 W 1 · km-1 at the wavelength of 1.55 μm and a total dispersion as low as ±2.5 ps · nm-1 · km-1 over an ultra-broad waveband range of the S-C-L band (wavelength from 1.46 μm to 1.625 μm) is optimized by adjusting its structure parameter, such as the lattice constant Λ , the air-filling fraction f , and the air-hole ellipticity η. The novel PCF with ultra-flattened dispersion, highly nonlinear coefficient, and nearly zero negative dispersion slope will offer a possibility of efficient super-continuum generation in telecommunication windows using a few ps pulses.     

高次柱面反射型太阳能聚光镜的光学设计

提出了一种新型高效太阳能聚光镜, 这种聚光镜用一组特定系数, a₂, a₄, a₆, a₈, a₁₀, a₁₂, a₁₄, a₁₆ 与 C的高次柱面内壁的一部分作为反射镜. 利用高次柱面方程和光反射定律, 推导出了在高次柱面内壁上太阳反射光束的方向矢量与高次柱面系数C, a₂,a₄, a₆, a₈, a₁₀, a₁₂, a₁₄, a₁₆的关系, 通过优化设计这些系数, 可以使入射到高次柱面内壁上的太阳光束反射后全部聚焦在一条与柱面母线平行的宽度很窄的线段上, 形成线聚光. 这组特定系数用粒子群优化算法求得, 并经计算机模拟证明其聚焦效果. 用这组特定系数的高次柱面作为聚光镜, 其对光的压缩比可达148倍, 其线性光斑可作为一种强光源或高温光源. 高次柱面反射镜可由金属或玻璃直接磨制而成, 也可由高次柱面骨架和铺设在骨架上的镀铝聚酯薄膜构成. 关键词： 太阳能聚光镜 高次柱面 多项式系数优化 线性聚焦     

仪表板黏弹阻尼减振设计

在分析结构阻尼的主要影响因素和过去仪表板减振结构设计特点的基础上，运用Kerwin约束阻尼结构减振理论和振动试验技术开展了仪表板的减振优化设计。采用对称型三弹性层约束阻尼结构板作为本仪表板的减振结构，同时设计了仪表板与固定支架、仪器之间两个连接边界处阻尼层预压量的调整结构。     

弱刚度件加固装夹技术

弱刚度件通过加固装夹可以提高刚度，实现其少无变形装夹；薄球壳利用加固装夹方法可以解决加工变形问题。     

混方体系ANFIS-GA建模与优化框架及应用

混方(配方)问题是为了寻求一种多组元的组分配合，使其在一定工艺条件下获得的产物性能达到最佳。因涉及到组分含量限制、工艺条件、成本约束等特殊性，且实验或生产实际中所积累的数据多为离散和／或不完整数据，加之性能-组分-工艺参数之间的关系复杂，传统的建模与优化方法难以得到满意的效果，特别是要同时优化工艺参数时。     

Control of gain and thermal carrier loss profiles for mode optimization in 980-nm broad-area vertical-cavity surface-emitting lasers

Optical gain and thermal carrier loss distributions regarding current diffusion and various electric contact areas are investigated to improve the near-field modes from the ring-shape to a Gaussian-like configuration for extra-broad-area and oxide-confined vertical-cavity surface-emitting lasers. In this work an equivalent circuit network model is used. The resistance of the continuously-graded distributed Bragg reflectors （DBRs）, the current diffusion and the temperature effect due to different electric-contact areas are calculated and analyzed at first, as these parameters affect one another and are the key factors in determining the gain and thermal carrier loss. Finally, the gain and thermal carrier loss distributions are calculated and discussed.     

Progress in superconducting qubits from the perspective of coherence and readout

Superconducting qubits are Josephson junction-based circuits that exhibit macroscopic quantum behavior and can be manipulated as artificial atoms.Benefiting from the well-developed technology of microfabrication and microwave engineering,superconducting qubits have great advantages in design flexibility,controllability,and scalability.Over the past decade,there has been rapid progress in the field,which greatly improved our understanding of qubit decoherence and circuit optimization.The single-qubit coherence time has been steadily raised to the order of 10 to 100μs,allowing for the demonstration of high-fidelity gate operations and measurement-based feedback control.Here we review recent progress in the coherence and readout of superconducting qubits.     

基于权重的子孔径拼接优化算法研究

为了提高大口径光学元件面形拼接检测准确度,减少传统子孔径拼接算法带来的误差传递和积累,并在原有全局优化拼接算法的基础上引入权重系数,使全口径内各相邻子孔径之间的重叠区域达到最优匹配,使拼接误差最小化.利用该优化算法对平面进行了多孔径拼接仿真模拟,在此基础上对150mm口径的平面镜进行了实验,并提出基于图像边缘轮廓特征提取的子孔径定位新方法,分析了影响拼接误差的因素.仿真和实验结果均证明了基于权重的全局优化拼接算法的有效性和可行性.