Configuration of an off-axis three-mirror system focused on compactness and brightness

We propose a configuration of an off-axis three-mirror system for maximum compactness and brightness. The chief ray is arranged to cross three times inside the system, and the system has a round configuration for compactness. We introduced into the design a ray triangle formed by the reflection points of the chief rays at the mirrors. The ray triangle indicates the size and the brightness of the system. Based on the proposed configuration, a design example of a 4 degrees x 4 degrees field of view is shown. The F-number of the system is 2.2, in close agreement with the estimation from the ray triangle.     

Wave-optical evaluation of interference fringes and wavefront phase in a hard-x-ray beam totally reflected by mirror optics

The intensity flatness and wavefront shape in a coherent hard-x-ray beam totally reflected by flat mirrors that have surface bumps modeled by Gaussian functions were investigated by use of a wave-optical simulation code. Simulated results revealed the necessity for peak-to-valley height accuracy of better than 1 nm at a lateral resolution near 0.1 mm to remove high-contrast interference fringes and appreciable wavefront phase errors. Three mirrors that had different surface qualities were tested at the 1 km-long beam line at the SPring-8/Japan Synchrotron Radiation Research Institute. Interference fringes faded when the surface figure was corrected below the subnanometer level to a spatial resolution close to 0.1 mm, as indicated by the simulated results.     

Semiconductor laser output modulated in GHz frequency region observed by image tube streak camera

The image tube streak camera was applied to the observation of fast modulated continuous light signals. Intensity modulation of a semiconductor laser was observed up to 5 GHz.     

Permeation behavior during the catalytic oxidation of CO in a Pt-loaded Y-type zeolite membrane

A Pt-loaded Y-type zeolite (Pt/NaY) membrane was prepared on the surface of a porous α-Al₂O₃ support tube by hydrothermal synthesis and then ion-exchanged with platinum. The thickness of the zeolite layer and the amount of Pt loaded were ca. and , respectively. The membrane was employed in the form of a cylindrical thin catalyst for the selective oxidation of CO in an H₂-rich mixture. A mixture of CO, O₂ and H₂ was fed to the outer surface of the membrane, and CO was selectively oxidized during its permeation through the thin layer. The permeation fluxes for H₂ and CO were determined at 423-. Permeation fluxes also calculated by means of a mathematical model using effective diffusion coefficients and reaction kinetics. The effective diffusion coefficients through the zeolite membrane were estimated from gas permeation test data, obtained at 423-, and the oxidation rates of CO were determined over a particulate catalyst that had the same composition as the Pt/NaY membrane. As a result, the diffusion coefficients of O₂, N₂ and CO were determined to be (0.7-1.0) at 423-, and the activation energies for the rate constants for CO oxidation were 61-. The predicted permeation fluxes of H₂ and CO using the mathematical model were in good agreement with the experimental data, when the oxidation selectivity of CO to H₂ was assumed to be 80% in the model calculation.     

Selection of two arm-swing strategies for bipedal walking to enhance both stability and efficiency

Walking ability, which involves mainly stability and efficiency, is one of the most important issues in humanoid robots. Effective use of a robot’s arms is expected to improve its walking ability under its body constraints. Although several types of arm-swing strategies have been proposed, they are difficult to execute simultaneously. We propose two-stage integration of these strategies to enhance both stability and efficiency. A selection algorithm for locomotion (SAL) selects the appropriate strategy according to the demands of the situation. In the first stage, two strategies are evaluated. One of them, Ro-SAL, entails use and compensation of the moment of the swing leg by hip rotation and arm swing. The other strategy, Su-SAL, entails the support of center of gravity trajectory tracking based on a predictive control. Ro-SAL is effective for the stable state and states with internal model error, whereas Su-SAL is effective in states with external force and environmental complexity. In the second stage of the proposed method (AS-SAL), the robot recognizes the current state and selects the optimal combination of the two arm-swing strategies. As a result, a humanoid robot can exhibit more efficient, stable bipedal walking without falling.     

被动型舞伴机器人结构设计

开发了一款轮式被动型舞伴机器人,机器人通过与人在直接身体接触条件下共同舞蹈,达到训练人类 跳舞的目的．鉴于机器人与人直接接触时存在安全风险,提出了一种新颖的机器人被动结构,该结构采用制动器取 代主动型机器人使用的电机等驱动器,因而机器人不能靠自身运动,只能根据人的作用力被动地运动,从而保障了 更高的安全性．通过使用运动捕捉系统分析男性舞蹈者的舞步,确定了既不会与人类发生运动干涉又能尽量减小运 动阻力的机器人车轮位置;此外,为了分析机器人的运动能力,引入了动力学可操作性,并最终确定了车轮的方向． 最后,给出了机器人样机,通过作者与机器人实际跳舞实验证明了结构的合理性．     

Raman microscopy of freeze-dried mouse eyeball-slice in conjunction with the "in vivo cryotechnique"

The wavelength of Raman-scattered light depends on the molecular composition of the substance. This is the first attempt to acquire Raman spectra of a mouse eyeball removed from a living mouse, in which the eyeball was preserved using the "in vivo cryotechnique" followed by freeze-drying. Eyeballs were cryofixed using a rapid freezing cryotechnique, and then sliced in the cryostat machine. The slices were sandwiched between glass slides, freeze-dried, and analyzed with confocal Raman microscopy. Important areas including various eyeball tissue layers were selected using bright-field microscopy, and then the Raman spectra were obtained at 240 locations. Four typical patterns of Raman spectra were electronically mapped on the specimen images obtained by the bright-field microscopy. Tissue organization was confirmed by embedding the same eyeball slice used for Raman spectra into epoxy resin and the thick sections were prepared with the inverted capsule method. Each Raman spectral pattern represents a different histological layer in the eyeball which was mapped by comparing the images of toluidine blue staining and Raman mapping with different colors. In the choroid and pigment cell layer, the Raman spectrum had two peaks, corresponding to melanin. Some of the peaks of the Raman spectra obtained from the blood vessels in sclera and the photoreceptor layer were similar to those obtained from the purified hemoglobin and rhodopsin proteins, respectively. Our experimental protocol can distinguish different tissue components with Raman microscopy; therefore, this method can be very useful for examining the distribution of a biological structures and/or chemical components in rapidly frozen freeze-dried tissue.     

Separation of co2-ch4 and co2-n2 systems using ion-exchanged fau-type zeolite membranes with different si/al ratios

FAU-type zeolite membranes with different Si/Al ratios were hydrothermally synthesized on the outer surface of a porous α-Al₂O₃ support tube. The permeances of the membranes to CO₂, CH₄ and N₂ were then measured at 308 K for single-component and equimolar binary systems. The separation properties were dependent on both the Si/Al ratio and the ion-exchange treatment. For single-component systems, a lower Si/Al ratio resulted in the incorporation of a larger number of Na⁺ ions. For a CO₂-CH₄ mixture, both CO₂ permeances and CO₂/CH₄ selectivities were approximately half the values obtained for a binary CO₂-N₂ mixture. The highest selectivities, obtained using the NaX(1) zeolite membrane, were 28 for CO₂/CH₄ and 78 for CO₂/N₂. The RbY, RbX(1) and RbX(2) zeolite membranes showed larger CO₂ permeances, compared with those of the original Na-type membranes. Ion-exchange with K⁺ ions was the most effective for the NaY zeolite membrane in that both the CO₂ permeance and the CO₂/CH₄ selectivity were increased.