Chemical modification of group IV graphene analogs

Mono-elemental two-dimensional (2D) crystals (graphene, silicene, germanene, stanene, and so on), termed 2D-Xenes, have been brought to the forefront of scientific research. The stability and electronic properties of 2D-Xenes are main challenges in developing practical devices. Therefore, in this review, we focus on 2D free-standing group-IV graphene analogs (graphene quantum dots, silicane, and germanane) and the functionalization of these sheets with organic moieties, which could be handled under ambient conditions. We highlight the present results and future opportunities, functions and applications, and novel device concepts.     

Image-analysis-based assessment of the effects of the "Ca2+-jump" technique on sarcomere uniformity

A new image analysis-based technique was used to quantitatively examine the effects of the "Ca2+-jump" activation protocol on the maintenance of fiber quality in skinned rabbit psoas muscle fiber segments. Specifically, contractions in pCa 4.6 were preceded by short-duration "preactivation" soaks in a solution in which EGTA was replaced with the low-Ca2+ buffering capacity analog hexamethylenediamine-N, N, N', N'-tetraacetate, which facilitated rapid Ca2+ equilibration within the fiber segments. Fiber quality was assessed by examining the Fourier spectra of the muscle fiber images before, during, and after activation. Segment lengths were typically below 500 micrometer, thus allowing the majority of the sarcomeres to be visualized in the field of view (x200 and x400 magnification). The preactivation protocol resulted in less deterioration of fiber quality with repetitive activation. In addition, there was also a significant reduction in the time required to reach the 50% level of maximum tension, with no significant change in the maximum tension level.     

The effect of cold cardioplegic cardiac arrest and electrically induced ventricular fibrillation on human cardiac beta-adrenoceptors during open-heart surgery

This study was designed to test the hypothesis that distinct alterations in cardiac beta-adrenoceptors (betaARs) may occur during cardiopulmonary bypass (CPB) alone, during CPB with cold cardioplegic cardiac arrest (CCCA), and during CPB with electrically induced ventricular fibrillation (EIVF). We assessed the density and affinity of right atrial betaARs in 27 patients undergoing open-heart surgery by (-)-[125I]iodocyanopindolol binding before CPB, defined as the "control," immediately after initiation, defined as "before," and immediately before the cessation of CCCA or EIVF, defined as "after." The density of betaARs was equivalent between the "control" and "before" groups; however, during CPB with EIVF, the density of betaARs decreased significantly (P < 0.001), whereas during CPB with CCCA, it increased significantly (P < 0.01). The rate of changes of the betaAR density was not correlated with the "before"-"after" interval, and the affinity of the betaARs did not change throughout these CPBs. These findings demonstrate that: CPB alone does not affect cardiac betaARs, at least until the onset of EIVF or CCCA; CPB with EIVF induces rapid desensitization of cardiac betaARs; and CPB with CCCA induces rapid sensitization of cardiac betaARs.     

Anisotropy in the resistive superconducting transition under magnetic fields in single crystal Pb2Sr2Ho0.5Ca0.5Cu3O8

Anisotropie properties of the single crystal Pb₂Sr₂Ho_0.5Ca_0.5Cu₃O₈ have been investigated by measuring the electrical resistivity in theab-planeρ _ab (H, θ,T), which depends on the angleθ between theab-plane and the magnetic-field direction, in various constant fieldsH perpendicular to the current direction. All the angle-dependent values ofρ _ab (H, θ,T) at a constant temperature are scaled to be on one curve as a function of reduced field. The anisotropic parameter γ≡(m _c ^* /m _ab ^* )^1/2 is estimated as 12–13, which is larger than that of YBa₂Cu₃O₇ and much smaller than that of Bi₂Sr₂CaCu₂O₈. It has been concluded that the anisotropy does not always depend on the thickness of the blocking layer but seems to depend on the overlap of the electronic wave functions along thec-axis. Anisotropy in the pinning potential has also been discussed from the resistive tail in the temperature dependence ofρ _ab (H,θ,T).     

Ultra light-weight and high-resolution X-ray mirrors using DRIE and X-ray LIGA techniques for space X-ray telescopes

We are developing novel ultra light-weight and high-resolution X-ray micro pore optics for space X-ray telescopes. In our method, curvilinear micro pore structures are firstly fabricated by silicon deep reactive ion etching (DRIE) or X-ray LIGA processes. Secondly, side walls of the micro structures are smoothed by magnetic field assisted finishing and/or hydrogen annealing techniques for high reflectivity mirrors. Thirdly, to focus parallel X-ray lights from astronomical objects, these structures are elastically or plastically bent into a spherical shape. Fourthly, the bent structures are stacked to form a multi-stage X-ray telescope. In this paper, we report on fabrication and X-ray reflection tests of silicon and nickel X-ray mirrors using the DRIE and LIGA processes, respectively. For the first time, X-ray reflections were confirmed on both of the mirrors. Estimated rms roughnesses were 5 nm and 3 nm for the silicon and nickel mirrors, respectively.     

A procedure to analyze surface profiles of the protein molecules visualized by quick-freeze deep-etch replica electron microscopy

Quick-freeze deep-etch replica electron microscopy gives high contrast snapshots of individual protein molecules under physiological conditions in vitro or in situ. The images show delicate internal pattern, possibly reflecting the rotary-shadowed surface profile of the molecule. As a step to build the new system for the "Structural analysis of single molecules", we propose a procedure to quantitatively characterize the structural property of individual molecules; e.g. conformational type and precise view-angle of the molecules, if the crystallographic structure of the target molecule is available. This paper presents a framework to determine the observed face of the protein molecule by analyzing the surface profile of individual molecules visualized in freeze-replica specimens. A comprehensive set of rotary-shadowed views of the protein molecule was artificially generated from the available atomic coordinates using light-rendering software. Exploiting new mathematical morphology-based image filter, characteristic features were extracted from each image and stored as template. Similar features were extracted from the true replica image and the most likely projection angle and the conformation of the observed particle were determined by quantitative comparison with a set of archived images. The performance and the robustness of the procedure were examined with myosin head structure in defined configuration for actual application.     

水力机械模型试验台的设计研究

扼要介绍在水力机械模型试验台建设中,对试验台的主管路系统、流量率定系统、扭矩测量系统等进行的研究。开发了闸板可抽取式强迫压紧特殊阀,杜绝了管路内漏现象的发生;引进了模型水轮机叶片角度联调机构,在保证叶片角度调整精度的同时又提高了工作效率;采取了保持试验水质清洁的相关措施,节约了宝贵的水资源。该试验台通过了由中国电机工程学会和中国水力发电工程学会组织的技术鉴定,达到国际先进水平。     

Fabrication of particle-free thin films by laser ablation combined with an electron beam

Particle-free silicon and nickel thin films were successfully fabricated by laser-ablating a melted section of their target surface, which gives a high evaporation pressure at the melting point. The influence of direct evaporation from a melted target was reduced negligibly by melting the target only locally with a focused electron beam (e-beam) and increasing the laser frequency. The silicon films fabricated by the present method, pulse laser deposition of a partially molten target, were able to firmly adhere to the substrates and withstood steel needle scratching, unlike e-beam-evaporated films.     

A novel bistable reflective display using quick‐response liquid powder

Abstract— We have developed new powder materials that exhibit liquid behavior, which can lead to the realization of novel bistable and reflective displays having paper‐white appearance, high contrast, and quick response. Two types of display were demonstrated, one had 160 × 160 array of pixels and the other had 320 × 320 in a 3.1‐in.‐diagonal viewable image size corresponding to 66 and 132 dpi, respectively. These displays were driven by passive‐matrix addressing. The displays showed a reflectivity of more than 41%, a contrast more than 1:10, and a pixel response time of less than 0.2 msec. The seven‐segment display for use in clocks was also demonstrated.     

Heat Capacity of Dilute 3He–4He Films on Graphite

The heat capacity of dilute ³He–⁴He films is measured to clarify whether the second adsorbed layer of ⁴He films on graphite solidify into the so-called “4/7 phase.” The ³He areal density is fixed at 0.2 nm^?2, whereas the ⁴He areal density is gradually increased. The measured heat capacities suddenly decrease with an increasing areal density approaching that of the 4/7 phase. Above the areal density of the 4/7 phase, the heat capacities do not reduce completely to zero and have finite values. The behavior of the heat capacity does not change over a rather wide areal density regime, although it suddenly increases or recovers at around the areal density of the third-layer promotion. These behaviors can be interpreted as the separation of ³He–⁴He mixture films into a ³He-rich phase and a ⁴He-rich phase, with the ³He-rich phase solidifying into the 4/7 phase and the ⁴He-rich phase remaining fluid below the areal density of the third-layer promotion. These observations strongly suggest that a ⁴He film adsorbed on a graphite surface does not solidify into the 4/7 phase.