Control System Synthesis by Sensitivity Considerations

The purpose of this paper is to provide a new open-loop control system synthesis method by active use of the system sensitivity. The concept of the combined system is, at first, introduced, which consists of both the originally given model of a physical system and its sensitivity model. Secondly, the controllability of it is analysed, where some interesting properties of the combined system constrollability are made clear. Thirdly, based on these controllability analyses, the method of the sensitivity synthesis is developed in the minimum energy problem with terminal constraints from the view point of making the terminal constraints more rigid against parameter perturbations. Several simple examples are given to illustrate the effectiveness of the present method. Finally, it is suggested that the undesirable effects of the existing slight nonlinearity neglected at the stage of modeling can be diminished in the same manner

Sub-Optimal Relay Control Systems for Non-Linear Plants with Chattering-Less Switching Line

It is well-known that the time-optimum or the minimum integrated-square-error control system for a second order linear plant is realized as a relay control system with a suitable switching line. In the present paper, first, it will be shown that such a relay system suffers so-called chattering phenomenon if there exists a soft-saturation type non-linearity on the velocity, however small it is. Second, it will be shown that the sub-optimal system with chatteringless switching line is easily obtained by introducing the method of instantaneous linearization. Two examples are given to demonstrate the effectiveness of the present method

Role of the limbus in femoral-head deformation in developmental dislocation of the hip: findings of two-directional hip arthrography.

Two-directional arthrographic findings made during conservative treatment of developmental dislocation of the hip were compared with the femoral-head configurations and radiological results obtained from long-term follow-up examinations in this retrospective study. Sixty hips were followed until at least age 14. Arthrography was carried out according to Terazawa's method. The shape of the superior, anterior, and posterior limbus was evaluated based on a modified Fujii's classification. The femoral-head configuration was classified into 4 groups, and the radiological results were evaluated using Severin's classification at the final observation. There was a statistically significant relationship between the shape of the anterior limbus, the number of portions of deformed limbus (superior, anterior, posterior), and the femoral-head configuration. Also, a statistically significant relationship between the shape of the limbus and Severin's classification was observed. These results suggest that the deformed limbus seems to play an important role in triggering femoral-head deformities, possibly via mechanical compression, and negatively affects development of the hip joint.</p

Light Element Production in the Circumstellar Matter of Energetic Type Ic Supernovae

We investigate energetic type Ic supernovae as production sites for Li6 and Be in the early stages of the Milky Way. Recent observations have revealed that some very metal-poor stars with [Fe/H]<-2.5 possess unexpectedly high abundances of Li6. Some also exbihit enhanced abundances of Be as well as N. From a theoretical point of view, recent studies of the evolution of metal-poor massive stars show that rotation-induced mixing can enrich the outer H and He layers with C, N, and O (CNO) elements, particularly N, and at the same time cause intense mass loss of these layers. Here we consider energetic supernova explosions occurring after the progeniter star has lost all but a small fraction of the He layer. The fastest portion of the supernova ejecta can interact directly with the circumstellar matter (CSM), both composed of He and CNO, and induce light element production through spallation and He-He fusion reactions. The CSM should be sufficiently thick to energetic particles so that the interactions terminate within its innermost regions. We calculate the resulting Li6/O and Be9/O ratios in the ejecta+CSM material out of which the very metal-poor stars may form. We find that they are consistent with the observed values if the mass of the He layer remaining on the pre-explosion core is 0.01-0.1 solar mass, and the mass fraction of N mixed in the He layer is about 0.01. Further observations of Li6, Be and N at low metallicity should provide critical tests of this production scenario.Comment: 12 pages, 2 figures, revised with referee suggestions, final version accepted in ApJ Letter

Controlling Electronic States of Few-walled Carbon Nanotube Yarn via Joule-annealing and p-type Doping Towards Large Thermoelectric Power Factor

Flexible, light-weight and robust thermoelectric (TE) materials have attracted much attention to convert waste heat from low-grade heat sources, such as human body, to electricity. Carbon nanotube (CNT) yarn is one of the potential TE materials owing to its narrow band-gap energy, high charge carrier mobility, and excellent mechanical property, which is conducive for flexible and wearable devices. Herein, we propose a way to improve the power factor of CNT yarns fabricated from few-walled carbon nanotubes (FWCNTs) by two-step method; Joule-annealing in the vacuum followed by doping with p-type dopants, 2,3,5,6-tetrafluo-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). Numerical calculations and experimental results explain that Joule-annealing and doping modulate the electronic states (Fermi energy level) of FWCNTs, resulting in extremely large thermoelectric power factor of 2250 mu Wm(-1) K-2 at a measurement temperature of 423K. Joule-annealing removes amorphous carbon on the surface of the CNT yarn, which facilitates doping in the subsequent step, and leads to higher Seebeck coefficient due to the transformation from (semi) metallic to semiconductor behavior. Doping also significantly increases the electrical conductivity due to the effective charge transfers between CNT yarn and F4TCNQ upon the removal of amorphous carbon after Joule-annealing

Supramolecular Complexation of \u3cem\u3eN\u3c/em\u3e-Alkyl- and \u3cem\u3eN\u3c/em\u3e,\u3cem\u3eN\u3c/em\u3e′-Dialkylpiperazines with Cucurbit[6]uril in Aqueous Solution and in the Solid State

Water seeds: Complex stoichiometry/composition and degree of oligomerization (oligomeric supramolecular complex formation) of cucurbit[6]uril (CB[6]) with N-alkyl- and N,N′-dialkylpiperazine were investigated in aqueous solutions by means of isothermal titration calorimetry (ITC), ESI-MS, NMR and light scattering measurements. Complex stoichiometry/composition and degree of oligomerization (oligomeric supramolecular complex formation) of cucurbit[6]uril (CB[6]) with N-alkyl- and N,N′-dialkylpiperazine were investigated in aqueous solutions by means of isothermal titration calorimetry (ITC), ESI-MS, NMR and light scattering measurements. It was found that the complex stability and the degree of oligomerization increase with elongating the alkyl chain attached to the piperazine core. X-ray crystallographic studies revealed a clear correlation between the structure of CB[6]–alkylpiperazine crystals obtained from aqueous solutions and the molecular weight/properties of host–guest oligomers existed in the solution as supramolecular “seeds” of crystal formation

Boolean Gröbner bases

In recent years, Boolean Gröbner bases have attracted the attention of many researchers, mainly in connection with cryptography. Several sophisticated methods have been developed for the computation of Boolean Gröbner bases. However, most of them only deal with Boolean polynomial rings over the simplest coefficient Boolean ring View the MathML source. Boolean Gröbner bases for arbitrary coefficient Boolean rings were first introduced by two of the authors almost two decades ago. While the work is not well-known among computer algebra researchers, recent active work on Boolean Gröbner bases inspired us to return to their development. In this paper, we introduce our work on Boolean Gröbner bases with arbitrary coefficient Boolean rings

Investigation of The Cause of Death in Inpatients with Dementia in Akitsu Konoike Hospital.

The mortality rate of patients with dementia is known to be higher than that of the general population. Pneumonia is one of the most common causes of death in patients with dementia, and proper intervention is important for clinical outcomes. To date, it remains unclear whether there are differences in the risk factors of pneumonia among different types of dementia. Here, we investigated the primary cause of death in patients with dementia admitted at Akitsu Konoike Hospital. Furthermore, Cox regression analyses were performed to evaluate the risk factors associated with death by pneumonia among patients with Alzheimer's dementia (AD), vascular dementia (VaD), and other conditions. We found that pneumonia was one of the most common causes of death in all of the current samples. Additionally, poor outcomes were associated with the Barthel index in AD and aging or short disease duration in VaD. These results suggest that considering the diagnostic differences in death by pneumonia is important for clinical treatment of patients with dementia

Origin of Thermal and Non-Thermal Hard X-ray Emission from the Galactic Center

We analyse new results of Chandra and Suzaku which found a flux of hard X-ray emission from the compact region around Sgr A$^\ast$ (r ~ 100 pc). We suppose that this emission is generated by accretion processes onto the central supermassive blackhole when an unbounded part of captured stars obtains an additional momentum. As a result a flux of subrelativistic protons is generated near the Galactic center which heats the background plasma up to temperatures about 6-10 keV and produces by inverse bremsstrahlung a flux of non-thermal X-ray emission in the energy range above 10 keV.Comment: to be published in PASJ, v.61, No.5, 200