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

Near-Optimal Control of Non-Linear Dynamic Plants with a Quadratic Performance Index

In this paper, a near-optimal control strategy is studied for high-order multi-variable non-linear dynamic plants under a quadratic performance index. The principal line of attack is to introduce the concept of instantaneous linearization and to apply the dynamic optimization technique originated by R. Bellman. The resulting configuration of the near-optimal control system presented here becomes a feedback one containing an on-line digital computer as a main control device. The general procedure proposed here is illustrated by the example of establishing the near-optimal control strategy for a dynamic plant with a non-linear characteristic. The control performance of the system is also discussed by comparing it with that of the system with the precisely optimal control strategy

Intrahepatic Cholangiocarcinoma with Sarcomatous Changes

A 61-year-old Japanese male was seen at an outside hospital with abdominal pain and distention. An intraabdominal mass was found on abdominal computed tomography (CT), and he was referred for further evaluation. He was afebrile, with mild tenderness in the upper abdomen and massive distention. Routine blood work showed severe inflammation and anemia. Repeat CT showed a large solitary heterogeneous mass, 25 cm in diameter, in the left upper quadrant with evidence of intratumoral bleeding and irregular enhancement peripherally. There was no clear distinction between the mass and the peripheral organs. Surgery was performed with persistent anemia and exacerbation of abdominal pain. Lateral segmentectomy, total gastrectomy, cholecystectomy and partial resection of the diaphragm and parietal peritoneum were performed. The final diagnosis was cholangiocarcinoma with sarcomatous changes. On the 16th postoperative day a CT scan revealed recurrent tumor. The patient died on the 34th postoperative day from rapid tumor progression

Inverse gene expression of prostacyclin and thromboxane synthases in resident and activated peritoneal macrophages 1The nucleotide sequence reported in this paper has been submitted to the GenBank/DDBJ/EMBL Data Bank under the accession number AB001607.1

AbstractProstacyclin and thromboxaneA2 produced from prostaglandinH2 are known to be important modulators with opposite biological activities. To examine possible roles of these prostanoids in immune responses, we have studied the gene expression of prostacyclin synthase (PGIS) and thromboxane synthase (TXS) in murine resident macrophages or in macrophages elicited with casein or bacillus Calmette-Guérin (BCG). Northern blot analyses showed that the PGIS mRNA was expressed in a decreasing order in the resident, and casein- and BCG-elicited macrophages. In contrast, the TXS mRNA was expressed in an increasing order in the resident, and casein- and BCG-elicited macrophages. On the other hand, the mRNA for cyclooxygenase-2, which produces PGH2 and participates in the production of prostanoids in inflammation, was expressed in both the resident and BCG-elicited macrophages but barely in the casein-elicited cells. In situ hybridization analysis showed that the expression of mRNAs for PGIS and TXS was ascribable not only to the alteration of the expression levels of both mRNAs in the each macrophage but also to the changes in subpopulations of the cells expressing these mRNAs. These observations suggested that the inverse gene expression of PGIS and TXS in macrophages contributes to immune responses by modulating the relative levels of prostacyclin and thromboxaneA2

Effect of Rust Inhibitor in Brine on Corrosion Properties of Copper

In this study, the effects of rust inhibitors in brine on corrosion behaviors of copper were investigated by measurement of cathode and anode polarization curves and an immersion test. For rust inhibitors, benzotriazole, sodium benzoate and sodium nitrite were prepared. From measurement results of cathode and anode polarization curves, it was found that the corrosion rate of copper in the benzotriazole solution is low and a stable passive film with excellent corrosion resistance generates on the surface of copper in the solution. In the case of the sodium benzoate solution, the corrosion resistance of the passive film was inferior to that in the benzotriazole solution although the passive film generated on the surface of copper. In contrast, the passive film scarcely generated on the surface of copper in the sodium nitrite solution. The result shows that the rust preventive effect of the solution to copper is weak. Furthermore, the immersion test revealed that the benzotriazole solution has the rust preventive effect to copper. In contrast, the effect of the sodium benzoate solution is weak and that of the sodium nitrite solution is scarcely expected