Dependence of Vacuum Electrical Breakdown Field and Field Enhancement Factor on the Number of Apertures Drilled in Small Electrodes

Dark current based on field emission current is considered to be a factor causing the vacuum electrical breakdown between multiaperture acceleration grids in the JT‐60 negative ion source. In this paper, we focus on field enhancement factor, which is a key parameter of field emission from the electrode. Vacuum breakdown testing for small‐sized electrodes simulating the multiaperture acceleration grids of the negative ion source was performed. We found the field enhancement factor and breakdown field for multiaperture electrodes, and we investigated the dependence of each parameter on the number of apertures. The results revealed that an increase in the average field enhancement factor after the end of conditioning resulting from an increase in the number of apertures led to a decrease in the dielectric strength of the multiaperture electrodes.     

Simple evaluation of aortic arch calcification by chest radiography in hemodialysis patients

Vascular calcification is associated with a poor prognosis in dialysis patients. It can be assessed with computed tomography but simple inoffice techniques may provide useful information. We compared the results obtained with a simple noninvasive technique with those obtained using multidetector computed tomography for aortic arch calcification volume (AoACV) in chronic hemodialysis (HD) patients. The enrolled study subjects were 63 (32 men and 31 women) maintenance HD patients. Calcification of the aortic arch was semiquantitatively estimated with a AoAC score (AoACS) on plain chest radiology. The AoACV was increased, with a mean value of 6.6 ranging from 0% to 36.5%. The coefficient of intraobserver variation was less than 2.5%. Aortic arch calcification score was highly correlated with AoACV (r=0.635, P<0.001). Multiple regression analysis showed age (F value=12.62, P<0.001) and pulse pressure (F value=4.54, P=0.037) to be significant independent determinants of AoACS. In conclusion, a simple measurement of AoACS may be useful for inoffice imaging to choose a therapeutic regimen in HD patients.     

Syndrome-decoding algorithms for static-diagnosis models

The problem of finding fault patterns consistent with a given syndrome is discussed for graph-theoretical diagnosis models such as the fault-diagnosis and self-diagnosis models. The fault-diagnosis model consists of two types of vertices, fault units and measurements, and is expressed by a bipartite graph. Faulty states of a fault unit always imply abnormal states of all the measurements which are adjacent to the unit, otherwise a measurement remains normal. A self-diagnosis model consists of one type of unit which has the capability of testing other units and being tested itself. The testing relation is represented by a directed arc; this produces test outcomes which are invalid if the testing unit is faulty. The inverse system which yields a fault pattern from a corresponding syndrome for fault-diagnosis models is studied and a syndrome-decoding algorithm is proposed which works for some class of diagnosis models with observation noise. The algorithm uses a similar measure to the syndrome-decoding algorithm of error-correcting codes which use the Hamming distance. Another measure is presented for the self-diagnosis model expressed by a directed graph and this measure is characterized by a ranking method.     

Novel active-R synthesis of a driving-point impedance

A novel active-R synthesis baaed on the single-pole rolloff characteristics of operational amplifiers is described. Various types of driving-point impedance, such as an inductance, frequency-dependent negative-resistance and frequency-dependent negative-inductance are systematically derived by the suitable choice of the amplifier transfer function. It is shown by experiments that the inductance simulator presents reliable high frequency performance.     

Thermostable Proteinase in Salted Anchovy Muscle

Salted anchovy fillets produced in Japan were severely degraded above 35°C and were solubilized completely in a few hours at 55°C. In contrast, raw anchovy fillets were not solubilized, but the solubility of fillets gradually increased during the salting process. In contrast, salted and raw anchovy fillets from southern Europe were relatively stable. Proteolytic activity that digested myosin heavy chain in vitro was found in muscle extracts from both types of salted fillets. Enzymes with activity were high-temperature-active serine proteinases with substrate specificities similar to trypsin. Optimal pH was 7.4 (Japan) and >8.5 (Europe). Neither enzyme showed collagen-degrading activity.     

Thermodynamic assessment of the Ni-Sb binary system

The Ni-Sb binary alloy system was thermodynamically assessed using CALPHAD approach in this article.Excess Gibbs energies of solution phases,liquid and fcc phases,were formulated using the Redlich-Kister expression.The intermediate phases were modeled by the sublattice model with (Ni,Va)0.5(Ni,Sb)0.25(Ni)0.25 for Ni3Sb_HT phase and (Ni,Va)0.3333(Sb)0.3333(Ni,Va)0.3333 for NiSb phase.The other phases including Ni3Sb,Ni7Sb3,and NiSb2 were treated as stoichiometric compound owing to their narrow composition ranges.Based on the reported thermodynamic properties and phase diagram data,the thermodynamic parameters of these phases were optimized,and the obtained values can reproduce the available experimental data well.     

Verification of Characteristics of a Boost‐Type Matrix Converter for a Three‐Phase Four‐Wire System

This paper describes an improvement to the control method of a boost‐type matrix converter (MC) for a three‐phase four‐wire system. The system is intended for use in a stand‐alone power source with a constant voltage and frequency. However, the conventional method is not able to control the output voltage with a low power‐factor load. To resolve this problem, we propose a new control method by using a MC and revising the conventional control method.     

Open-loop Stackelberg strategies in a linear-quadratic differential game with time delay

The open-loop Stackelberg strategies in a linear-quadratic differential game with time delay are constructed in the form of necessary and sufficient conditions. The evolution of a game with time delay is described by coupled differential equations composed of lumped and distributed parameter subsystems. Calculation of solutions is facilitated by transforming two-point boundary-value problems to terminal boundary-value ones by the introduction of Riccati-type differential equations.     

Diagnosis model for dynamical systems Part 2. Continuous system

While most existing systems requiring diagnosis are dynamical, most models proposed for diagnosis are static. Consequently, a mathematical model of differential equations is used for a model-based diagnosis of dynamical systems. Although this model-based diagnosis has been well studied, it is not used much in practice owing to the computational difficulty and the difficulty of obtaining the mathematical model. We propose a diagnosis model for continuous dynamical systems. The model can be expressed by a signed directed-graph, which has been studied extensively in qualitative matrix theory. We interpret these qualitative results in terms of the diagnosis model, and also present new results for the model. The dynamic aspects of the qualitative stabilities of the model are mainly discussed. The distinguishability of the sign pattern is also studied with a new concept of invariant fault pattern defined in the model. Strategies for monitoring as well as for the diagnosis of the dynamical systems are derived by these qualitative results.     

A diagnosability analysis by means of fault distance

A new concept of fault distance is introduced in a failure-diagnosis model. Diagnosability measures such as t-fault diagnosability and t/s-diagnosability are expressed in terms of the fault distance. A new diagnosability measure of partial t-fault diagnosability characterized in terms of fault distance is proposed. In addition, the fault distance of various types of self-diagnosis models are expressed in graph theoretical terms. Applying the fault distance to various types of self-diagnosis models, conditions for diagnosabilities of these models, which have been studied separately, are obtained in a unified manner. Conditions for t-fault diagnosability and sufficient conditions for t/s-diagnosability are obtained with this fault distance.