An efficient manufacturing method for I-shaped cross-sectional CFRP beam with arbitrary arrangement of carbon fiber using electro-activated resin molding

Abstract

The I-shaped cross-sectional beam of CFRP (CFRP I-beam) is usually manufactured by the continuous protrusion method. Carbon fibers can only be arranged in the longitudinal direction. The CFRP I-beam with arbitrary arrangement of carbon fiber was manufactured with applying the electro-activated deposition molding method. The carbon fiber fabric was immersed in the deposition solution and energized, epoxy resin precipitated around carbon fiber and impregnated. The resin-impregnated fabric was installed to the mold, and the CFRP I-beam was fabricated. The CFRP I-beam was subjected to three-point bending tests, and the relationship between load-deflection was simulated by finite-element analysis.     

Dynamical System Analysis of Unsteady Phenomena inCentrifugal Compressor

INTRODUCTI0NUnsteadyphenomenaappearedinacentrifugalcompressorsystematlowflowratearecharacterizedbysurgeandrotatingstall.Thesurgeisknowntocauseoscillationswithlargeamplitudeofthefiowrateandthepressurerisethrough0utacompressorsys-tem.Ontheotherhand,ther0tatingstallcauseslocalflowoscillationsandappearsinsomepartsofacompressor,suchastheinducer,theimpellerandthediffuser-Sincetheydeterioratethecompressorperfor-manceands0metimesleadtothesystembreakd0wn,itisimportanttoknowthephysicalmechanismsofth…     

Numerical investigation of loss generation mechanisms of flow in turbomachinery by using curved square duct

The secondary flow within a passage of turbomachinery exhibits a complex flow pattern by the effect of the centrifugal and the Coriolis forces. The passage vortex in this secondary flow generates a major part of the losses. However, the mechanism of the loss generation has not been fully clarified yet. In this point of view, the passage vortex is closely examined by the computational method using the two-dimensional curved square ducts as fundamental models. The inlet boundary layer thickness and the inlet velocity distortion are considered to be the major parameters affecting the generation of passage vortex in the present study. The computed results revealed that the passage vortex gave the predominant effects for the generation of loss not only in the breakdown process but also in the development process.     

Ionic‐Liquid Gating of InAs Nanowire‐Based Field‐Effect Transistors

Here, the operation of a field‐effect transistor based on a single InAs nanowire gated by an ionic liquid is reported. Liquid gating yields very efficient carrier modulation with a transconductance value 30 times larger than standard back gating with the SiO₂/Si₊₊ substrate. Thanks to this wide modulation, the controlled evolution from semiconductor to metallic‐like behavior in the nanowire is shown. This work provides the first systematic study of ionic‐liquid gating in electronic devices based on individual III–V semiconductor nanowires: this architecture opens the way to a wide range of fundamental and applied studies from the phase transitions to bioelectronics.     

NPPC/NPR2 signaling is essential for oocyte meiotic arrest and cumulus oophorus formation during follicular development in the mouse ovary

Natriuretic peptide type C (NPPC) and its high affinity receptor, natriuretic peptide receptor 2 (NPR2), have been assumed to be involved in female reproduction and have recently been shown to play an essential role in maintaining meiotic arrest of oocytes. However, the overall role of NPPC/NPR2 signaling in female reproduction and ovarian function is still less clear. Here we report the defects observed in oocytes and follicles of mice homozygous for Nppc(lbab) or Npr2(cn), mutant alleles of Nppc or Npr2 respectively to clarify the exact consequences of lack of NPPC/NPR2 signaling in female reproductive systems. We found that: i) Npr2(cn)/Npr2(cn) female mice ovulated a comparable number of oocytes as normal mice but never produced a litter; ii) all ovulated oocytes of Npr2(cn)/Npr2(cn) and Nppc(lbab)/Nppc(lbab) mice exhibited abnormalities, such as fragmented or degenerated ooplasm and never developed to the two-cell stage after fertilization; iii) histological examination of the ovaries of Npr2(cn)/Npr2(cn) and Nppc(lbab)/Nppc(lbab) mice showed that oocytes in antral follicles prematurely resumed meiosis and that immediately before ovulation, oocytes showed disorganized chromosomes or fragmented ooplasm; and iv) ovulated oocytes and oocytes in the periovulatory follicles of the mutant mice were devoid of cumulus cells. These findings demonstrate that NPPC/NPR2 signaling is essential for oocyte meiotic arrest and cumulus oophorus formation, which affects female fertility through the production of oocytes with developmental capacity.     

Examining efficient instructional methods for computer-aided brush coating skill training system in elementary and secondary education

In recent Japan, many elementary and secondary school children strongly feel an awareness of resistance toward manufacturing class. It is considered as one of the aversion causes to science and engineering. We suspect that the shortage of teacher’s manufacturing experience is related to this background. So, the authors previously have developed a brush coating skill training system with a haptic device to improve the ability. In the skill training, historically, the instruction method while reproducing the video of trainee’s action has been considered to be effective. Thus, our developed system includes a software system to visualize the brush coating motion. This software system can record trainee’s brush coating motion and visualize the data in virtual three-dimensional space, so the advisor and the trainee can share his/her skill level and the wrong motion such as extra shaking and tilt by reproducing his/her past training data on a computer screen. In this paper, to improve the learning effectiveness of our brush coating skill training system, some kinds of instructional methods are designed, and the difference of the instructional methods is analyzed based on the proposed criteria. This paper performed some experiments with 10 college students who have less experience of brush coating. From the analysis results, the most effective instruction method was clarified.     

Positive charge generation due to species of hydrogen during NBTI phenomenon in pMOSFETs with ultra-thin SiON gate dielectrics

Negative bias temperature instability (NBTI) of pMOSFETs with ultra-thin SiON gate dielectrics was investigated. We focused our attention on the behavior of hydrogen atoms released from the interface under NBT stress. From the transient characteristics of pMOSFETs after NBT stresses were stopped, it was found that a portion (60%, in our case) of hydrogen atoms released by the NBT stress remain in a 1.85-nm-thick NO-oxynitride gate dielectric. The existence of the hydrogen in the gate dielectric was shown to lead to the generation of positive charges.     

Comparison of the Reactivity of Carbohydrate Photoaffinity Probes with Different Photoreactive Groups

A judicious choice of photoreactive group is critical in successful photoaffinity labeling studies of small molecule–protein interactions. A set of carbohydrate‐based photoaffinity probes was prepared to compare the effects of three major photoreactive groups on the efficiency and selectivity of crosslinking a binding protein with low affinity. We showed that, despite the low crosslinking yield, the diazirine probe displayed the high ligand‐dependent reactivity consistent with the ideal mechanism of photoaffinity labeling. Moreover, we demonstrated that, among the three photoreactive groups, only the diazirine probe achieved highly selective crosslinking of a low‐affinity binding protein in cell lysate.