Abstract N ‐Substituted 2‐alkylthio‐1,4‐dihydro‐4,4,6‐trimethylpyrimidines easily reacted with methanol to give corresponding 2‐methoxy‐1,4‐dihydropyrimidines, while the other nucleophiles did not react on the C‐2 carbon of the pyrimidine rings. However, the substitution of alkylthio group easily proceeded intramolecularly even with weak nucleophilic groups, e.g. , phenolic oxygen, thiophenolic sulfur, and anilino nitrogen atom, to yield bi‐ or tricyclic pyrimidine derivatives.
Ketenimines were conveniently synthesized from N-monosubstituted thioacetamides with dehydrating agents such as 2-chloro-1,3-dimethylimidazolinium chloride or 2-chloro-1-methylpyridinium iodide.
The purpose of this study is to investigate the effects of the physical vapor deposition (PVD) and gas-nitriding on the fatigue properties of titanium alloy (Ti-4.5Al-3V-2Mo-2Fe). Rotational bending fatigue tests were performed on five types of specimens; that are uncoated, TiN coated, gas-nitrided, annealed after TiN coating, and Ti-TiN coated. We obserbed the fracture process. The results are summarized as follows : 1) The fatigue strength of the gas-nitrided specimen was decreased less than that of the untreated and TiN coated specimens. This is because the matrix grain size increased because of a high temperature nitriding process (800℃ for 4 hours). 2). Fatigue limit of Ti-TiN coated specimens that was maked to progress fatigue strength of titanium alloy (Ti-4.5Al-3V-2Mo-2Fe) was decreased less than that of TiN coated specimens. This is because : firstly Ti coated surface was highly rough, secondly the thickness of Ti film was much smaller than that of diflusion layer of gas-nitrided specimen.
Rotational bending fatigue tests were performed on a medium carbon steel(S35C) coated with thermally sprayed Ni-based self-fluxing alloy, under the condition of a fixed fusing temperature of 1010℃ to clarify the relationship between fatigue properties and fusing time. Fusing time varied from 200 seconds to 10 hours. As a result of these fatigue tests, the specimen fused 200 seconds showed the lowest fatigue strength, because every specimen of this series showed delamination between substrate and coating layer. In the specimens without delamination under cyclic loading, a gradual reduction in fatigue strength was observed with the increase of fusing time. There exists an adequate fusing time which brings the highest fatigue strength between 200 seconds and 30 minutes in the fusing process.
The increase of the free energy density due to a given distribution of the antiferromagnetic magnetization 2µBn(r) is written as a function of temperature, magnetic field, n(r) and its derivatives. To get a stable sinusoidal modulation of a simple antiferromagnetic order, the ordinary and higher-order exchange stiffness constants are expected to be negative and positive, respectively. New interaction energies between elastic strains and derivatives of n(r), besides the ordinary magneto-elastic energy, are introduced to explain the transition between transversal and longitudinal spin density waves and the anisotropies, relative to the directions of modulation and polarization, of the susceptibility and dilatation and the anisotropy of orbital susceptibility is discussed; the nature of the transition at the Néel temperature is also discussed. The temperature variations of the maximum moment of SDW, specific heat and susceptibility are calculated and are compared with the experimental results for chrominum.
We investigated the damage process of GFRP cross-ply laminates which have outer-ply 90° plies (e.g. [90/0]s). While [0/90]s laminates form symmetric cracks, staggered cracks occur in [90/0]s laminates. To simulate the failure process of [90/0]s laminates, we proposed a numerical model based on the finite element method. In this model, we used cohesive elements to simulate the occurrence and the propagation of ply cracks and delaminations. We found that simulated results agreed well with the experimental data. We confirmed the validity of the numerical model for the damage process of [90/0]s laminates.
Development of Unmanned Deep Foundation Construction Method in Shaft Masao Shimizu, Kenzi Sasaki, Takuro Shigeno, Akio Hirata, Hironobu Nagase, Tomoo Mimura Pages 237-245 (1997 Proceedings of the 14th ISARC, Pittsburgh, USA, ISSN 2413-5844) Abstract: Deep founadtions, because of their economical merits, are used as foundation for steel transmission towers and bridges which are provided in mountain areas, as well as for landslide-restrainig pile at scarps. However, the most of the works, such as excavation are implemented in a narrow circular vertical shaft by human labor, with extremely severe work environment. Improvement of work environment, enhancement of safety, labor saving, shortening of construction period and cost reduction for deep foundation works by mechanization and automation are of primary concern. To overcome these difficulties, we have successfully developed a comprehensive unmanned construction system which is very innovative in conception and able to cover, from excavation to concrete placing, that is, "unmanned deep foundation construction method in aft". The paper outlines various technology elements, including the deep founadtion excavator, the results of field tests, as well as its applicability to the foundation for steel transmission tower and the expected improvements. Keywords: No keywords DOI: https://doi.org/10.22260/ISARC1997/0029 Download fulltext Download BibTex Download Endnote (RIS) TeX Import to Mendeley
The effect of the forced magnetostriction on various thermodynamic properties of Invar alloys is examined. The temperature variations of the thermal expansion coefficient and bulk modulus defined at constant magnetization and the concentration dependences of this bulk modulus and the high-field susceptibility at constant volume are shown to be normal. There is an enhancement due to the magnetovolume coupling in the high-field susceptibility, compressibility and forced magnetostriction. The various anomalies are attributed to the large magnetovolume coupling in Fe–Ni Invar alloys. It is seen that Fe–Pt alloys are rather normal at low temperature. The magnetovolume coupling term is calculated in a simple itinerant electron model for fcc Fe–Ni alloys. To explain the large magnetovolume coupling in Fe–Ni alloys, the homogeneous itinerant electron model is not sufficient and a magnetic inhomogeneity with different atomic volumes will explain this discrepancy.
