594 research outputs found
Indentation of an elastic arch on a frictional substrate: Pinning, unfolding and snapping
We investigate the morphology and mechanics of a naturally curved elastic
arch loaded at its center and frictionally supported at both ends on a flat,
rigid substrate. Through systematic numerical simulations, we classify the
observed behaviors of the arch into three distinct types of configurations in
terms of the arch geometry and the coefficient of static friction with the
substrate. A linear theory is developed based on a planar elastica model
combined with Amontons-Coulomb's frictional law, which quantitatively explains
the numerically constructed phase diagram. The snapping transition of a loaded
arch in a sufficiently large indentation regime, which involves a discontinuous
force jump, is numerically observed. The proposed model problem allows a fully
analytical investigation and demonstrates a rich variety of mechanical
behaviors owing to the interplay between elasticity, geometry, and friction.
This study provides a basis for understanding more common but complex systems,
such as a cylindrical shell subjected to a concentrated load and simultaneously
supported by frictional contact with surrounding objects
A quantum chemical model for a series of self-assembled nanocages: the origin of stability behind the coordination-driven formation of transition metal complexes up to [MââLââ]ÂČâŽâș
Herein, we present a systematic computational model to study the electronic states and free energies of a self-assembled multi-metal complex series. By combining the previously developed model Hamiltonian approach for transition-metal complexes and the generalized Born model, the thermodynamics, optimized geometries, and electronic states of the [Pd12L24]24+ nanocage are revealed, together with [PdnLm]2n+ complex series. The effective model Hamiltonian is a theoretical method to obtain the d-electron wavefunction and potential energy including interaction energy between the transition-metal and ligands. In the present improvement, the electronic state on each transition-metal center is focused as a building unit and solved under the whole electronic field of the assembling system. We realize a reliable and systematic treatment of multi-transition-metal complexes with different sizes and charges. Consequently, our model could reproduce binding energies of the [PdnLm]2n+ complex series quantitatively as compared to density functional theory (DFT). Regarding free energy, we revealed that the assembling solute becomes unstable due to the electrostatic interaction, and effects of the solvent and counter anions mainly compensated it. Optimized geometries were also analysed. The local square-planar coordination structures around the palladium centres were characterized in the complex series. The relationships between the entire symmetrical geometries and the local coordination structures are also discussed. Finally, electronic structures of the [Pd12L24]24+ nanocage were well characterized as a single-determinant, where only dx2ây2 is unoccupied due to the ligand-field effect. We also found that the solvent polarized the electronic states of the Pd ions, whereas the counter anion suppressed the polarization. The present method realizes size-independent reliable and rapid computations, and therefore can be expected to further application studies on self-assembly dynamics
Compressor with Turning-Paired Vane and Piston
With the aim of energy saving of room air conditioners, we are addressing higher efficiency of the rotary compressor that is used most in the world. We focused on a new rotary compressor equipped with a mechanism to restrict the rolling motion of the piston, and performed the dynamics analysis. The new rotary compressor has a small pillar at the tip of the vane and constitutes a turning pair of vane and piston, and it limits the rolling motion of the piston. By means of limiting the piston rotation, the heat transfer to the suction process from the compression chamber will be suppressed, and we can expect higher compression efficiency. Before examining the compression efficiency, we performed the dynamics analysis of this new rotary compressor and examined the forces and dynamic behavior of the components, and the mechanical efficiency of the compressor. Then we have following results. (1)We can clarify the contact point between the vane tip and piston in the turning pair by considering the equilibrium of forces and moments acting on the vane. (2)By reducing the diameter of the pillar at the vane tip, the vane tip friction loss is reduced, and the mechanical efficiency is improved. (3)The new rotary compressor has less vane tip friction loss and on the other hand greater friction loss between the vane side and the cylinder in comparison to the rolling piston rotary compressors. As a result, both compressors have almost the same mechanical efficiency
A novel A792D mutation in the CSF1R gene causes hereditary diffuse leukoencephalopathy with axonal spheroids characterized by slow progression
Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is an autosomal dominant white matter disease that causes adult-onset cognitive impairment. The clinical manifestations are a variable combination of personality and behavioral changes, cognitive decline, parkinsonism, spasticity, and epilepsy. In 2012, mutations in the gene encoding colony stimulating factor 1 receptor (CSF1R) were identified as the cause of HDLS. As the numbers of reported mutations are limited, the understanding of whole pathogenesis needs accumulation of disease-causing mutations with detailed clinical descriptions. We describe a Japanese family with autosomal dominant adult-onset cognitive impairment and characteristic white matter lesions. Genetic testing revealed a novel p.A792D mutation in the tyrosine kinase domain of CSF1R in two affected family members. The symptom profile of the present cases mostly matched the previously reported cases, with the notable exceptions of late-onset and long disease duration
Legitimation of Income Inequality in Japan: A Comparison with South Korea and the United States
This paper was submitted to the Research Network Q âAsian Capitalismsâ of the 2019 SASE annual conference in New York and won the 2019 FFJ/SASE Award for the Best Paper on Asia. This research was supported by JSPS KAKENHI Grant Number JP16H03688.Why does Japan have a large earnings gap between regular and non-regular employment? We attempt to answer this question through the lens of the legitimation of inequality, assuming the possibility that the inequality remains unresolved because it is legitimized due to institutional settings in Japanese society. In this paper, we explore to what extent the inequality is legitimized, as well as how it is legitimized, in Japanese society by analyzing data collected from a comparative vignette survey on the just income of fictitious workers in comparison with South Korea and the United States. The results of multilevel model analysis show that the income gap between regular and non-regular employees is accepted as just in Japan and South Korea. Moreover, non-regular worker respondents think that the income gap should be wider than regular worker respondents do (against their own interests) only in Japan. To some extent, the acceptance of income inequality and its over-acceptance by non-regular workers can be explained by the assumed difference in the duties and opportunities in the workplace between regular and non-regular employees, which is brought about by the male breadwinner model and Japanese firmsâ practices to secure the livelihood of employees and their families. Based on the results, we argue that the income inequality between regular and non-regular employment in Japan has a stronger logic of legitimation and, therefore, is more likely to persist than in other countries
Measurement of AGN dust extinction based on the near-infrared flux variability of WISE data
We present the measurement of the line-of-sight extinction of the dusty torus
for a large number of obscured active galactic nuclei (AGNs) based on the
reddening of the colour of the variable flux component in near-infrared (NIR)
wavelengths. We collected long-term monitoring data by for 513 local AGNs catalogued by the
BAT AGN Spectroscopic Survey (BASS) and found that the
multi-epoch NIR flux data in two different bands (WISE and ) are
tightly correlated for more than 90% of the targets. The flux variation
gradient (FVG) in the and bands was derived by applying linear
regression analysis, and we reported that those for unobscured AGNs fall in a
relatively narrow range, whereas those for obscured AGNs are distributed in a
redder and broader range. The AGN's line-of-sight dust extinction () is
calculated using the amount of the reddening in the FVG and is compared with
the neutral hydrogen column density () of the BASS catalogue. We
found that the ratios of obscured AGNs are greater than those
of the Galactic diffuse interstellar medium (ISM) and are distributed with a
large scatter by at most two orders of magnitude. Furthermore, we found that
the lower envelope of the of obscured AGNs is comparable to
the Galactic diffuse ISM. These properties of the can be
explained by increase in the attributed to the dust-free gas
clouds covering the line of sight in the broad-line region.Comment: 11 pages, 7 figures, published in MNRA
Role of CD59 in experimental glomerulonephritis in rats
Role of CD59 in experimental glomerulonephritis in rats. CD59 is a molecule which is present on the host cell membranes and inhibits formation of membrane attack complex. A monoclonal antibody, 6D1, recognizes a rat analogue of human CD59. 6D1 inhibits function of rat CD59 and can enhance complement-mediated hemolysis in vitro. To assess the role of CD59 in complement-mediated glomerular injury, 6D1 was tested in a model of experimental glomerulonephritis induced by a lectin and its antibodies. The left kidney of a rat was perfused either with 200 ”g of Lens culinaris hemoagglutinin (LCH) plus 1mg of 6D1 (IgGl fraction) (Group I and III) or with LCH only (Group II) through a cannula placed in the left renal artery. All the perfusate was discarded from a cannula in the renal vein. The holes in the artery and vein were repaired by microsurgery and the blood circulation was re-established. Rats were injected either with 0.125ml of rabbit anti-LCH serum (Group I and II), or with normal rabbit serum (Group III) via tail vein one minute after the recirculation. Fifteen minutes after injection, significant C9 deposition in the glomeruli was observed only in Group I, whereas C3 deposition in Group I and II were comparable. At Day 4, total glomerular cells, proliferating cells, glomerular expression of intercellular adhesion molecule-1 and fibrin deposition in Group I were all significantly increased when compared with Group II. At Day 7, number of total glomerular cells and leukocytes in the glomeruli of Group I were significantly higher than in Group II. The glomeruli in Group III appeared normal throughout experiments. These data indicate that the functional inhibition of a rat analogue of human CD59 worsens complement-mediated glomerular injury in vivo
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