Time dependence of mesoscopic strain distribution for triaxial woven carbon-fiber-reinforced polymer under creep loading measured by digital image correlation

This paper presents the time dependence of the mesoscopic strain of a triaxial woven carbon-fiber-reinforced polymer under creep loading measured using digital image correlation (DIC). Two types of DIC techniques were employed for the measurement: conventional subset DIC and mesh DIC. Static tensile and creep tests were carried out, and the time dependence of the mesoscopic strain distribution was investigated by applying these techniques. The ultimate failure of this material is dominated by inter-bundle decohesion caused by relative rigid rotation and relating shear stress. Therefore, these were focused on in the present study. During the creep tests, the fiber directional strain, shear strain, and rotation were monitored using the DIC, and the mechanism for the increase in the specimen’s macro-strain over time was investigated based on the results obtained by the DIC measurement.     

Emergency response to the nuclear accident at the Fukushima Daiichi Nuclear Power Plants using mobile rescue robots

On March 11, 2011, a massive earthquake (magnitude 9.0) and accompanying tsunami hit the Tohoku region of eastern Japan. Since then, the Fukushima Daiichi Nuclear Power Plants have been facing a crisis due to the loss of all power that resulted from the meltdown accidents. Three buildings housing nuclear reactors were seriously damaged from hydrogen explosions, and, in one building, the nuclear reactions became out of control. It was too dangerous for humans to enter the buildings to inspect the damage because radioactive materials were also being released. In response to this crisis, it was decided that mobile rescue robots would be used to carry out surveillance missions. The mobile rescue robots needed could not be delivered to the Tokyo Electric Power Company (TEPCO) until various technical issues were resolved. Those issues involved hardware reliability, communication functions, and the ability of the robots' electronic components to withstand radiation. Additional sensors and functionality that would enable the robots to respond effectively to the crisis were also needed. Available robots were therefore retrofitted for the disaster reponse missions. First, the radiation tolerance of the electronic componenets was checked by means of gamma ray irradiation tests, which were conducted using the facilities of the Japan Atomic Energy Agency (JAEA). The commercial electronic devices used in the original robot systems operated long enough (more than 100 h at a 10% safety margin) in the assumed environment (100 mGy/h). Next, the usability of wireless communication in the target environment was assessed. Such tests were not possible in the target environment itself, so they were performed at the Hamaoka Daiichi Nuclear Power Plants, which are similar to the target environment. As previously predicted, the test results indicated that robust wireless communication would not be possible in the reactor buildings. It was therefore determined that a wired communication device would need to be installed. After TEPCO's official urgent mission proposal was received, the team mounted additional devices to facilitate the installation of a water gauge in the basement of the reactor buildings to determine flooding levels. While these preparations were taking place, prospective robot operators from TEPCO trained in a laboratory environment. Finally, one of the robots was delivered to the Fukushima Daiichi Nuclear Power Plants on June 20, 2011, where it performed a number of important missions inside the buildings. In this paper, the requirements for the exploration mission in the Fukushima Daiichi Nuclear Power Plants are presented, the implementation is discussed, and the results of the mission are reported.     

Influence of the methyl group on the dielectric constant of boron carbon nitride films containing it

LSI interconnect insulators made using low dielectric constant (low-k) materials are required for high performance devices with a small RC delay. We investigated a boron carbon nitride film containing the methyl group (Me–BCN) using tris-di-methyl-amino-boron (TMAB: B[N(CH₃)₂]₃) gas as a low-k material. In addition, we studied the influence of the methyl group on the dielectric constant (k-value) and the properties of the Me–BCN films. It was found that the k-value of the Me–BCN films decreases with increasing number of C–H bonds due to the methyl group (CH₃). The number of O–H bonds due to water incorporation is suppressed by increasing the number of C–H bonds. Consequently, we suggested that a lower k-value can be realized by the suppression of water invasion by a hydrophobic surface due to methyl bonds. Thus, the control of the methyl group is important to achieve a low-k material using Me–BCN films.     

Effect of the radio-frequency power on the dielectric properties of hydrogen-containing boron carbon nitride films deposited by plasma-assisted chemical vapor deposition using tris(dimethylamino)boron gas

We investigated the properties of boron carbon nitride film containing hydrogen (BCNH film) deposited using tris(dimethylamino)boron as the source gas. The dielectric constant (k) of BCNH film decreases with decreasing radio-frequency plasma power used for deposition, and can be as low as 1.8 at 10 W. Thermal desorption spectroscopy analysis shows that the film contains a large amount of hydrogen. Fourier transform infrared spectroscopy shows an absorption band at 2960 cm−1, attributed to the asymmetrical stretching mode of C-H in the methyl group. It is thought that increasing the number of C-H bonds, which have a low polarizability, can achieve a lower k value.     

Changes in the characteristics of CuInGaSe2 solar cells under light irradiation and during recovery: degradation analysis by the feeble light measuring method

Changes in the characteristics of CuInGaSe₂ solar cells in response to light irradiation were investigated. Then these changes, which suggest long-term degradation, were clarified using the measurement technique by feeble light. The thin-film cell of this type is considered to be “ever stable”. A stable result over the short term was also obtained in the light accelerated test of 2-SUN performed in this experiment. On the other hand, it was found that the characteristics measured with feeble light show a remarkable change over time. As a result of measuring at 0.065–105 mW/cm² light intensity, the change rate of cell output power was so intense the measurement light was weak. This finding reflects the increase in an internal defect and suggests a possibility that light irradiation exerts the influence on long-term cell performance. Moreover, by measuring with feeble light, we found that the changed output recovers by reverse voltage application. The phenomenon of recovery up on comparatively low reverse voltage can be considered as an application for maintaining stability.     

Built-in folded monopole antenna for handsets

A built-in folded monopole antenna for handsets (BFMA) is introduced and investigated. The characteristics of the BFMA are compared with those of a planar inverted-F antenna (PIFA), which is one of the conventional handset antennas. As a result, it has been confirmed that the BFMA has smaller size and wider bandwidth compared with the PIFA.     

由紧凑型高dI／dt门极驱动单元驱动的新型对称门极换流晶闸管

在工业大功率应用领域已经推出了多种类型（对称，非对称以及逆向导通）的门极换流晶闸管（GCT）器件，为了用它来实现更高性能、更加合适的系统，人们期望对门极换流晶闸管展开进一步的研究，本文提出了对称门极换流晶闸管的一种新方案。     

Primary human immunodeficiency virus type 1 viremia and central nervous system invasion in a novel hu-PBL-immunodeficient mouse strain

We established four new mouse strains with defective T and B cells as well as defects in innate immunological reactions using an NK cell depletion antibody and showed that all mutant mouse strains efficiently received human peripheral blood leukocyte (PBL) engraftment (hu-PBL-scid mice). Higher levels of human immunodeficiency virus type 1 (HIV-1) replication were observed in these new hu-PBL-scid mice than in conventional hu-PBL-C.B-17-scid mice. In one particular strain, hu-PBL-NOD-scid mice, high levels of HIV-1 viremia (more than 10(6) 50% infectious doses per ml) were detected after infection with HIV-1. The plasma viral load was about 100 to 1,000 times higher than that observed in other hu-PBL-scid mice infected with HIV-1. Although high-level viremia did not correlate with the total amount of HIV-1 RNA in cells from infected mice, high levels of free virions were detected only in hu-PBL-NOD-scid mice. HIV-1 viremia induced systemic HIV-1 infection involving the liver, lungs, and brain. PCR in situ hybridization confirmed that HIV-1-infected cells invaded the brain tissue of the hu-PBL-NOD-scid mice. Our results suggest that the genetic background, including innate immunity, is critical in the development of primary HIV-1 viremia and subsequent central nervous system invasion with HIV-1. The hu-PBL-NOD-scid mouse represents a useful model for the study of the pathogenesis of HIV-1 in vivo, especially brain involvement, and therapy of primary HIV-1 viremia.     

Surgical analysis for metastatic lung tumor from renal cell carcinoma

Metastatic lung tumor from renal cell carcinoma were studied in 29 cases. Eighteen patients were treated surgically, 11 were treated non-surgically. The overall 5-year survival rate with the patients of pulmonary resection was 53.5%, and that with those of conservative therapy was 0%, and this difference is statistically significant (p < 0.05). There was no significant difference in any characteristics such as sex, age, stage, grade, disease free interval, metastatic pattern and combination with or without interferon therapy. There was no significant difference in surgically treated patients with pulmonary metastasis in terms of any factors such as age, sex, stage, grade, disease free interval, pulmonary metastasis pattern, metastatic number, surgical procedure, combination with or without interferon therapy statistically. Analysis for the surgically treated patients with pulmonary metastasis from renal cell carcinoma shows no significant difference in prognosis with any characteristics. This result shows efficacy of surgery even if for the patients with synchronous bilateral multiple pulmonary metastasis from renal cell carcinoma.