Density wave v.s. magnetic breakdown: Mechanism of high-field phase transition in α-(BEDT-TTF)2XHg(SCN)4

We study the density wave instability under magnetic fields for the two-band two-dimensional electron system with the interband coupling due to the magnetic breakdown. We consider a model system having a pair of open Fermi surfaces and a closed Fermi surface, whose low-temperature state is a density wave phase caused by the nesting of open Fermi surfaces. Under the influence of magnetic fields, the density wave transition is suppressed by the magnetic breakdown coupling with the closed Fermi surface. We apply this model to the high-magnetic-field phase transition observed in the quasi-two-dimensiona1 organic conductors (BEDT-TTF)₂XHg(SCN)₄.     

Subjective evaluation of visual fatigue due to misalignment of motion and still images in a stereoscopic display

Abstract— In this paper, the relative influences of misalignment such as cross‐talk, vertical shift, and motion blur on visual fatigue by using a binocular stereoscopic display has been verified. Experiments were conducted for two cases: a still image and a motion image. They were evaluated by using the simulator sickness questionnaire (SSQ). By changing the disparity angle, cross‐talk, and vertical shift in the still‐image experiment, it was found that the SSQ score of each parameter increased as the amount of each factor increased. With a two‐sample t‐test between the presence and absence of each factor, a significant difference was found for the case of a more than 36‐arcmin disparity, more than 20% cross‐talk, and more than 10% vertical shift. In the motion‐image experiment, in which motion speed and the misalignment were varied, it was found that movement of the disparity angle caused much more visual fatigue in comparison with the misalignment factors, which were cross‐talk and vertical shift. In contrast, motion images in addition to the cross‐talk and/or vertical shift had a slight but unnoticeable relationship to an increase in visual fatigue. Therefore, it was concluded that vertical shift dominated the evaluation for still images, and the movement itself dominated the evaluation for motion images. The results suggest that it is necessary to evaluate visual fatigue according to the representing case, still or motion images, of a 3‐D stereoscopic display.     

Creep mechanisms of a new Ni-Co-base disc superalloy at an intermediate temperature

The microstructures of a new Ni-Co-base disc superalloy, TMW-4M3, before and after the creep test at 725 °C/630 MPa have been systematically investigated by transmission electron microscopy (TEM). The crept microstructures were marked as three different deformation stages (I, II and III) corresponding to the gradually increased strain. At stage I, stacking fault (SF) shearing was the main deformation mechanism. The SF was extrinsic and lay on {111} plane. However, deformation microtwinning became the dominant mode at stage II and III. The average spacing of deformation twins decreased from 109 ± 15 nm at stage II to 76 ± 12 nm at stage III, whereas the twin thickness did not change significantly. The influence of stacking fault energy (SFE) of γ matrix on the deformation mechanism is discussed. It is suggested that lower SFE in TMW-4M3 is partly responsible for the enhanced creep resistance.     

An optical projection system with mirrors for laparoscopy

We propose an optical projection system aimed at improving laparoscopic surgery based on three-dimensional (3D) measurement that gives an effective information for robotic-assisted surgery and computer-aided surgery. Laparoscopic surgery, which involves the creation of small ports through the patient’s body for the laparoscope and surgical instruments, such as clamp, is minimally invasive and has generated a growing interest. There are techniques using the stereo laparoscope to obtain depth information. Active sensing when structured light is added to the laparoscope can reconstruct a 3D shape. However, active sensing that requires projection devices for the structured light leads to an increase in size. Large-sized projection and sensing systems affect surgical procedures. The size of the system is also larger than the size of port for the laparoscope. To remove the obstacle for the surgery, it is important to design downsized systems. For active sensing with the structured light, a small-size projection system is required to use a small port for the laparoscope. Therefore, we built the optical projection system toward downsizing the device to stereoscopic vision of the laparoscope using mirrors, and we show a new shape reconstruction method from its active sensing. Our Experimental results demonstrate the effectiveness of this proposed system and method.     

Gradient‐Domain Photon Density Estimation

The most common solutions to the light transport problem rely on either Monte Carlo (MC) integration or density estimation methods, such as uni‐ & bi‐directional path tracing or photon mapping. Recent gradient‐domain extensions of MC approaches show great promise; here, gradients of the final image are estimated numerically (instead of the image intensities themselves) with coherent paths generated from a deterministic shift mapping. We extend gradient‐domain approaches to light transport simulation based on density estimation. As with previous gradient‐domain methods, we detail important considerations that arise when moving from a primal‐ to gradient‐domain estimator. We provide an efficient and straightforward solution to these problems. Our solution supports stochastic progressive density estimation, so it is robust to complex transport effects. We show that gradient‐domain photon density estimation converges faster than its primal‐domain counterpart, as well as being generally more robust than gradient‐domain uni‐ & bi‐directional path tracing for scenes dominated by complex transport.     

Ultraviolet Photoelectron Spectroscopy of Two Titanium Metal Atoms Encapsulated Metallofullerenes, Ti2@C80 and Ti2@C84

Ultraviolet photoelectron spectra (UPS) of Ti₂@C₈₀ (mixture of two isomers) and two Ti₂@C₈₄ isomers excited by synchrotron radiation light source are presented. The spectra of Ti₂@C₈₀ are complicated compared with those of other metallofullerenes, which is considered with an aid of molecular orbital (MO) calculation. The photoelectron spectra of two Ti₂@C₈₄ isomers are fairly analogous with each other and show less structure than that of Sc₂@C₈₄. This suggests that the symmetry of two isomers differs from D_2d symmetry of Sc₂@C₈₄.     

Observation of ferroelectric domains in bismuth-layer-structured ferroelectrics using Raman spectroscopy

Raman spectroscopy has been used to investigate the domain structures in bismuth-layered-structured ferroelectrics (BLSFs). In Bi₄Ti₃O₁₂ single crystal, the lowest frequency mode (soft mode) at 30 cm⁻¹ appears exclusively for the xx polarization configuration (xpolar axis). We found that the polarization dependence of the Raman signal exhibits spatial symmetries that reflect the presence of different domain variants present in Bi₄Ti₃O₁₂. This highly anisotropic character of the soft mode shares with other BLSFs such as Bi_3.25La_0.75Ti₃O₁₂ and SrBi₂Ta₂O₉, which demonstrate the usefulness of the soft-mode spectroscopy for the study of ferroelectric domain structures in BLSFs. We also applied Raman spectroscopy to in situ observation of domain structures in Bi₄Ti₃O₁₂ under applied electric field.     

Fuzzy Decision-Making Tool for Environmental Sustainable Buildings

Several alternatives are being attempted to obtain the sustainable residential building, based on the acceptable level of environmental impact and socio-economic characteristics of residential building. These criteria are in conflict each other, thus it is very difficult to assess or find the sustainable residential building. This paper presents a methodology of the assessment for residential building that is intended to assist the decision making for the building planners or practitioners. The results show that this approach can effectively work for the quantitative evaluation and selection of the best alternative of the residential buildings considered, especially when conflict relation exists. This approach allows the planner or construction companies to test design strategies against different sets of criteria.     

微型金属注射成形制品质量的改善

本研究的目的是改善微型金属注射成形(μ-MIM)制品的质量。为此，研究着重于混练与注射成形的工艺。采用不同容量的三种型号混练机和二种型号注射机以制备混练料粒和微型哑铃形试样。测定了混练料粒的烧结密度和重量损失，也考虑了微型哑铃试样的烧结密度与强度。计算了每项性能的变动系数(CV)值，并讨论了均匀性。结果表明，较小的混炼机和注射机制造的试样，重量损失、烧结密度和强度的变化程度较小。