Optimum Feedback Control of AC-DC Parallel Transmission System

This paper describes a method of damping a system oscillation on an ac-dc parallel transmission system by applying the optimum feedback law. The optimum feedback control can be obtained by solving the Riccati matrix equation for the linearized system equation. The reference value of the constant current control system of the dc system is chosen as the control variable. The method is applied to a generator feeding an infinite-bus through an ac-dc parallel transmission system, and its effectiveness is ascertained

Internal Stress in Electrodeposited PbO₂

The change of internal stress in the electrodeposited PbC₂ from a lead nitrate bath was observed by measuring the deflection of a thin platinum anode during electrodeposition of PbC₂ on one side of it. The crystal structure of the deposits was determined by X-ray diffraction. After the electrodeposition, the change of deflection of the deposited Pb₂ was observed under the following conditions : a) Keep the deposited PbO₂ in air or in a lead nitrate bath at constant temperatures. b) Discharge the cell, Pt/PbNO₃ electrolyte/PbO₂ deposit, by connecting it to an external circuit with some resistance. The results obtained are summarized as follows : 1) The crystal structure of α-PbO₂ was observed in the deposits which had deflected in the direction of contraction during electrodeposition, and β-PbO₂ was observed in the deposits which had deflected in the direction of expansion during electrodeposition. 2) After the electrodeposition, the deposits deflected gradually in the direction of expansion when they were kept in air or left in the bath. The amount of deflection of the deposits of α-PbO₂ was larger than that of the deposits of β-PbO₂ within the same time duration. 3) The electrodeposited PbO₂ deflected in the direction of expansion by discharging the cell, and the amount of deflection of the deposits of α-PbO₂ was larger than that of the deposits of β-PbO₂

Appropriate Amounts and Activity of the Wilms’ Tumor Suppressor Gene, wt1, Are Required for Normal Pronephros Development of Xenopus Embryos

The Wilms’ tumor suppressor gene, wt1, encodes a zinc finger-containing transcription factor that binds to a GC-rich motif and regulates the transcription of target genes. wt1 was first identified as a tumor suppressor gene in Wilms’ tumor, a pediatric kidney tumor, and has been implicated in normal kidney development. The WT1 protein has transcriptional activation and repression domains and acts as a transcriptional activator or repressor, depending on the target gene and context. In Xenopus, an ortholog of wt1 has been isolated and shown to be expressed in the developing embryonic pronephros. To investigate the role of wt1 in pronephros development in Xenopus embryos, we mutated wt1 by CRISPR/Cas9 and found that the expression of pronephros marker genes was reduced. In reporter assays in which known WT1 binding sequences were placed upstream of the luciferase gene, WT1 activated transcription of the luciferase gene. The injection of wild-type or artificially altered transcriptional activity of wt1 mRNA disrupted the expression of pronephros marker genes in the embryos. These results suggest that the appropriate amounts and activity of WT1 protein are required for normal pronephros development in Xenopus embryos