Observation of Tungsten Field Emitter Tips with an Ultra-High Resolution Field Emission Scanning Electron Microscope

Tungsten emitter tips are observed with a prototype scanning electron microscope with an approximate SA electron beam size at an accelerating voltage of 30kV. A field emission electron source and in-lens type objective lens are incorporated into the electron column. A special specimen stage was designed to clean the emitter tips using a flashing operation and to reduce contamination by heating them during the observation. The observed emitters were W\u3c 011 \u3e, W\u3c 001 \u3e and Ti/W\u3c 001 \u3e. The crystallographic planes were clearly visible in the W\u3c 011 \u3e and W\u3c 001 \u3e observation. It was also possible to observe atomic layer steps of 4.5A during the recrystallization process by flashing operation of W\u3c 011 \u3e. In the observation of Ti/W, it was found that the aspect was quite different from that of the W\u3c 001 \u3e crystal surface. The observed field emission micrograph pattern was in good agreement with the tip shape

Energy band bending induced charge accumulation at fullerene/bathocuproine heterojunction interface

The electronic properties of fullerene (C60)/bathocuproine (BCP)/Ag heterostructures were studied as a function of the BCP layer thickness by photoemission spectroscopy. For the thin BCP layer, the energy levels are flat and gap states exist at the interface. In contrast, energy band bending occurs at the C60/BCP interface when the BCP layer is thick, resulting in a considerable barrier for electron transport and therefore causing charge accumulation in organic solar cells. The results reveal that a thin BCP layer gives a much more favorable energy level structure and conform that charge accumulation is responsible to the anomalous current-voltage (I-V) curve

ESD Protection Design Optimization Using a Mixed-Mode Simulationand

Abstract -This paper presents a new optimization method of ESD protection design using a mixed-mode ESD simulation with a calibrated model based on DC and TLP characteristics. As a result, the influence of power bus line resistance on ESD protection design is clarified using the calibrated model for each device used in ESD protection circuit. ESD surge flows into an internal circuit easily as the value of the power bus line resistance increases even if the ESD tolerance of a power clamp element is high enough

Hypermineralization of Hearing-Related Bones by a Specific Osteoblast Subtype

Auditory ossicles in the middle ear and bony labyrinth of the inner ear are highly mineralized in adult mammals. Cellular mechanisms underlying formation of dense bone during development are unknown. Here, we found that osteoblast-like cells synthesizing highly mineralized hearing-related bones produce both type I and type II collagens as the bone matrix, while conventional osteoblasts and chondrocytes primarily produce type I and type II collagens, respectively. Furthermore, these osteoblast-like cells were not labeled in a “conventional osteoblast”-specific green fluorescent protein (GFP) mouse line. Type II collagen-producing osteoblast-like cells were not chondrocytes as they express osteocalcin, localize along alizarin-labeled osteoid, and form osteocyte lacunae and canaliculi, as do conventional osteoblasts. Auditory ossicles and the bony labyrinth exhibit not only higher bone matrix mineralization but also a higher degree of apatite orientation than do long bones. Therefore, we conclude that these type II collagen-producing hypermineralizing osteoblasts (termed here auditory osteoblasts) represent a new osteoblast subtype. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).Kuroda Y., Kawaai K., Hatano N., et al. Hypermineralization of Hearing-Related Bones by a Specific Osteoblast Subtype. Journal of Bone and Mineral Research, 36, 8, 1535. https://doi.org/10.1002/jbmr.4320

Dust from Comet 209P/LINEAR during its 2014 Return: Parent Body of a New Meteor Shower, the May Camelopardalids

We report a new observation of the Jupiter-family comet 209P/LINEAR during its 2014 return. The comet is recognized as a dust source of a new meteor shower, the May Camelopardalids. 209P/LINEAR was apparently inactive at a heliocentric distance rh = 1.6 au and showed weak activity at rh < 1.4 au. We found an active region of <0.001% of the entire nuclear surface during the comet's dormant phase. An edge-on image suggests that particles up to 1 cm in size (with an uncertainty of factor 3-5) were ejected following a differential power-law size distribution with index q=-3.25+-0.10. We derived a mass loss rate of 2-10 kg/s during the active phase and a total mass of ~5x10^7 kg during the 2014 return. The ejection terminal velocity of millimeter- to centimeter-sized particles was 1-4 m/s, which is comparable to the escape velocity from the nucleus (1.4 m/s). These results imply that such large meteoric particles marginally escaped from the highly dormant comet nucleus via the gas drag force only within a few months of the perihelion passage.Comment: 18 pages, 4 figures, accepted on 2014 December 11 for publication in the Astrophysical Journal Letter

Growth and structure analysis of tungsten oxide nanorods using environmental TEM

WO3 nanorods targeted for applications in electric devices were grown from a tungsten wire heated in an oxygen atmosphere inside an environmental transmission electron microscope, which allowed the growth process to be observed to reveal the growth mechanism of the WO3 nanorods. The initial growth of the nanorods did not consist of tungsten oxide but rather crystal tungsten. The formed crystal tungsten nanorods were then oxidized, resulting in the formation of the tungsten oxide nanorods. Furthermore, it is expected that the nanorods grew through cracks in the natural surface oxide layer on the tungsten wire