Nagoya Institute of Technology

About: Nagoya Institute of Technology is a education organization based out in Nagoya, Japan. It is known for research contribution in the topics: Thin film & Catalysis. The organization has 10766 authors who have published 19140 publications receiving 255696 citations. The organization is also known as: Nagoya Kōgyō Daigaku & Nitech.

Factors affecting cyclic durability of all-solid-state lithium polymer batteries using poly(ethylene oxide)-based solid polymer electrolytes

Abstract: In this paper, the electrochemical properties and performances of all-solid-state lithium polymer batteries (LPBs) using standard PEO-based solid-state polymer electrolytes (SPEs) are reported and discussed. The assembled cell showed stable charge–discharge cycles (>150 cycles) at 30 °C. This is due to desirable solid electrolyte interface (SEI) film formation at the SPE | cathode interface at the first cycle indicated by activation energy measurements for interfacial Li ion exchange reaction. However, sudden capacity fading for prolonged electrochemical cycles was indicated by an accelerated aging test at higher current density (1 C) and temperature conditions (60 °C), accompanied by an increase of electrochemical polarization. This degradation phenomenon may be fatal for practical usage of large-scale batteries which requires extremely long-time durability. Two sequential factors affecting the capacity fading are proposed through the studies of in situ19F-NMR imaging, real-time monitoring of the total cell thickness, and electrochemical measurements such as AC impedance. One factor is degradation of the cathode sheet or cathode composite assembly, owing to cyclic volumetric change from the two-phase LiFePO4–FePO4 reaction. Such degradation leads to uneven electric contact at the electrode | electrolyte interface, thereby enhancing local electrochemical polarization. The second factor, namely, Li salt decomposition, is triggered by this local polarization, giving rise to the continuous capacity fading and the increase of polarization. This degradation scenario can be general enough to include the full range of all-solid-state LPB devices, since the trigger of degradation owes to non-fluidity of solid | solid contact, or solid electrolytes cannot immerse into the cavities caused by pulverization of cathode particles unlike liquid electrolytes. On the basis of these results, we attempted to improve the mechanical properties of the binder materials of cathode sheets, and demonstrated improved cyclic durability.

Genome-wide analysis of DNA copy number alterations and gene expression in gastric cancer.

Abstract: Genomic copy number aberrations (CNAs) are believed to play a major role in the development and progression of human cancers. Although many CNAs have been reported in gastric cancer, their genome-wide transcriptional consequences are poorly understood. In this study, to reveal the impact of CNAs on genome-wide expression in gastric cancer, we analysed 30 cases of gastric cancers for their CNAs by array comparative genomic hybridization (array CGH) and 24 of these 30 cases for their expression profiles by oligonucleotide-expression microarray. We found that with the application of laser microdissection, most CNAs were detected at higher frequency than in previous studies. Notably, gain at 20q13 was detected in almost all cases (97%), suggesting that this may play an important role in the pathogenesis of gastric cancer. By comparing the array CGH data with expression profiles of the same samples, we showed that both genomic amplification and deletion strongly influence the expression of genes in altered genomic regions. Furthermore, we identified 125 candidate genes, consisting of 114 up-regulated genes located in recurrent regions (>10%) of amplification and 11 down-regulated genes located in recurrent regions of deletion. Up-regulation of several candidate genes, such as CDC6, SEC61G, ANP32E, BYSL and FDFT1, was confirmed by immunohistochemistry. Interestingly, some candidate genes were localized at genomic loci adjacent to well-known genes such as EGFR, ERBB2 and SMAD4, and concordantly deregulated by genomic alterations. Based on these results, we propose that our list of candidate genes may contain novel genes involved in the pathogenesis of advanced gastric cancer.

Microwave dielectric properties and crystal structure of homologous compounds ALa4Ti4O15 (A = Ba, Sr and Ca) for base station applications

Abstract: Homologous compounds ALa4Ti4O15 (A = Ba, Sr and Ca) with high dielectric constant ϵr and quality factor Q × f are candidate materials for dielectric resonators in base station of telecommunication systems. We have investigated the relationship between the microwave dielectric properties and crystal structure of these new materials. Single crystals of CaLa4Ti4O15 were synthesized to analyze the crystal structure precisely. The ceramic discs of the ALa4Ti4O15 (A = Ba, Sr and Ca) were also synthesized and the microwave dielectric properties were measured. Ba-analogy showed the highest ϵr of 44.4 due to the large cationic movement. Ca-analogy showed the highest Q × f of 50,246 GHz due to resemblance in ionic radius between Ca2+ (r = 1.34 A: 12-coordination) and La3+ (r = 1.36 A: 12-coordination) ions. Sr-analogy showed near zero temperature coefficient of resonant frequency τf of −8.4 ppm/°C compared with the others. The relationships between their crystal structures and properties were discussed.