Music stage design

Until comparatively recently the specific acoustic needs of performers, and the means of satisfying these, has played second fiddle to the achievement of satisfactory audience listening conditions in auditoria. This paper presents a personal view of music stage design based on the author's experience in architecture and acoustics and on the results of recent research. Local reflections and the possible influence of stage and auditorium rake are discussed and guidelines for the salient features of orchestral stages are suggested.     

Laser amplifier design

Often one wants a laser amplifier system to produce an output pulse of a specific form, e.g., time shape, energy, etc. Given any potential amplifier configuration one needs to find the proper input pulse which, when propagated through the amplifier system, results in the desired output pulse. Efficient operation of the amplifier (large energy extraction) usually implies that the response of the laser medium is nonlinear, which makes such a calculation very tedious if attempted on a hit and miss basis. Here we discuss a procedure which enables one to systematically generate the proper input pulse. Once the input is known it is straightforward to determine whether the amplifier configuration is suitable.     

Precise multipass Herriott cell design: derivation of controlling design equations

Multipass Herriott cells are often designed using the thin lens approximation, which results in approximate dimensions or imperfect patterns due to both spherical aberration and the finite width of the optic. We derive the design equations for exact solutions to the Herriott cell problem. We also show that Herriott cells using spherical mirrors cannot be designed such that multiple concentric beam patterns all meet their reentrant condition. We derive a solution for elliptical mirrors that allows this condition to be met simultaneously for many beams.     

SHER-HIAF ring lattice design

The Super Heavy Experimental Ring (SHER), which is one of the rings of the next accelerator complex High Intensity Heavy Ion Accelerator Facility (HIAF) at IMP, has to be optimized for e-cooling. Its lattice is designed for two modes: the first is the isochronous mode, which is a time-of-flight mass spectrometer for short-lived secondary nuclei, the second is the storage ring mode, which is used for collecting and cooling the secondary rare isotope beams from the transport line. In order to fulfil its purpose, the ion optics can be set to different ion optical modes.     

Wideband film polarizer design

The reflection and transmittance of s- and p-polarized lights should be treated separately at nonzero angle incidence. By choosing two special film materials whose refractive indices meet the Brewster condition in a given incident angle, the reflection of p-polarized light can be eliminated. When the two materials are fabricated into multilayer stacks, the reflection of s-polarized light can be largely increased while the reflection of p-polarized light keeps low. According to this principle, a film polarizer with bandwidth of 198 nm or even more is designed.     

任意长度喷管型面设计方法在气动激光器喷管设计中的应用

 将一种新的任意长度喷管型面设计（ALN）方法应用于气动激光器喷管型面设计,在相同的喷管出口设计马赫数、喷管喉部高度及喷管扩张段长度条件下,设计了4条ALN方法喷管型面,并和一条最短长度（MLN）喷管型面作对比,采用2维气动激光器增益场仿真方法对5个喷管的小信号增益场进行仿真。计算结果表明:ALN方法可以有效地实现增益场分布的控制,选择合理的设计参数得到的喷管长度比MLN喷管更短,小信号增益更大。     

交指型腔体滤波器设计

为抑制EAST装置现场的电磁信号对低杂波系统运行的干扰,设计了一个交指型腔体滤波器,其中心频率为2.45GHz,带宽为0.245GHz。介绍了交指型腔体滤波器的设计思路和方法,利用高频电磁仿真软件HFSS仿真提高了设计效率和精度。     

SHER-HIAF ring lattice design

The Super Heavy Experimental Ring （SHER）, which is one of the rings of the next accelerator complex High Intensity Heavy Ion Accelerator Facility （HIAF） at IMP, has to be optimized for e-cooling. Its lattice is designed for two modes： the first is the isochronous mode, which is a time-of-flight mass spectrometer for short-lived secondary nuclei, the second is the storage ring mode, which is used for collecting and cooling the secondary rare isotope beams from the transport line. In order to fulfil its purpose, the ion optics can be set to different ion optical modes.     

One-dimensional photonic crystal design

In this article we present a method to determine the band spectrum, band gaps, and discrete energy levels, of a one-dimensional photonic crystal with localized impurities. For one-dimensional crystals with piecewise constant refractive indices we develop an algorithm to recover the refractive index distribution from the period map. Finally, we derive the relationship between the period map and the scattering matrix containing the information on the localized modes.     

光学设计的发展

本文概述了光学设计所处的历史发展阶段,对智能化光学设计给出了定性的描述,指出了目前光学设计要解决的问题以及发展方向。     

Developments in studio design

The acoustic characteristics of studios have always been of even greater importance than the characteristics of live auditoria because the listener is divorced from the visual cues which can aid concentration and the direction of attention. Background noise acquires a much enhanced ability to mask the desired sounds, while imbalances in the frequency response can create unnatural sensations and the acoustic perspective created may even conflict with the general aim of the programme.Probably because of the early appreciation of the requirements of acoustic design, dramatic changes in recent years have not been necessary and the emphasis has rested more on the economic provision of acceptable conditions in small spaces.     

Binary subwavelength diffractive-lens design

We present a procedure for the design of binary diffractive lenses with pulse-width-modulated subwavelength features. The procedure is based on the combination of two approximate theories, effective medium theory and scalar diffraction theory, and accounts for limitations on feature size and etch depth imposed by fabrication. A design example is presented.     

Pattern-specific neural network design

We present evidence that the performance of the traditional fully connected Hopfield model can be dramatically improved by carefully selecting an information-specific connectivity structure, while the synaptic weights of the selected connections are the same as in the Hopfield model. Starting from a completely disconnected network we let genuine Hebbian synaptic connections grow, one by one, until a desired degree of stability is achieved. Neural pathways are thus fixed notbefore, butduring the learning phase.     

OCAD与其他光学设计程序及应用软件的链接和互动

介绍了OCAD(optical CAD)光学设计软件包与国内外其他著名光学设计软件，如美国ORA公司的CodeV，Focus Software公司的Zemax，还有OSLO、LENSVIEW、ASAP和TRACEPRO等，以及国内SOD 88等的链接及互动方法。指出OCAD光学设计软件包本身不仅具有光学设计软件最基本的功能，而且可以利用自身功能界面随时调用上述软件程序为其所用，做到各程序间有效链接，行为互动;OCAD光学设计软件包还可以和文字处理及工作报表等通用程序，如Word和Excel等程序进行链接和互动。针对我国光学设计和光学制图的国家标准，部颁标准及企业标准推出了面向国内的OCAD光学设计软件包。提出目前国内外有关光学设计软件的功能及特点已非常丰富，没必要重复研制内容相同的新软件，只有针对自身的特殊需要研制一些专用应用软件即可。     

分离作用RFQ膜片电极的优化设计

用RELAX3D模拟分离作用射频四极场(SFRFQ)加速结构中傍轴下的电场分布，并分析了膜片孔径、加速间隙等参数对粒子能量增益的影响，找到了设计SFRFQ电极的一般方法，使得在极间电压为70kV的情况下(以O⁺为例)，粒子通过一个周期单元，可获得100keV以上的能量增益，小球微扰法的测量值与模拟结果能很好的符合. 关键词： 分离作用射频四极场 RELAX3D 能量增益 反场