Y. S. Chang

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A new type of RF-photonic sensor design which uses an optical serially-fed phased array is proposed for applications in radar and communication systems. This sensor has the advantages of true time delay and yet only requires one tunable laser and one fiber optic grating delay for beam steering. In addition to discussing the system operation in transmit and(More)
—Extension of a new optically controlled serially fed phased-array system to the receive mode of operation has been demonstrated. Our system uses the pulsed nature of microwave radars in a manner similar to clocked systems used in digital configurations. This novel approach requires only the use of one tunable laser, one optical modulator, and one chirped(More)
We report a case of renin-secreting juxtaglomerular cell tumor which developed in a hypertensive 47-yr-old Korean man. Presumptive clinical diagnosis was made before surgery based on the high level of plasma renin and the radiologic evidence of renal mass. Grossly, a round, bulging, well-encapsulated mass of 3 x 3 cm was located in the mid-portion of the(More)
— A new optically controlled phased-array system has been developed that has all the advantages of true time delay (TTD), yet only requires one tunable laser, one optical modulator, and one fiber-optic grating unit. In this letter, a two-element serial-feed transmitter has been assembled and tested to demonstrate the feasibility of this novel concept.(More)
'Pauci-immune' glomerulonephritis has been recognized as an important cause of rapidly progressive glomerulonephritis. The paucity of immune deposits can be separated from the other two major immunohistologic variants of crescentic glomerulonephritis, ie, antiglomerular basement membrane (GBM) antibody-mediated and immune complex-mediated(More)
We report a patient with systemic lupus erythematosus (SLE), who had developed metabolic alkalosis during plasmapheresis. The metabolic alkalosis could be promptly corrected by reducing the amount of citrate load. The development of metabolic alkalosis can be explained by the citrate load during plasmapheresis. Careful monitoring of acid base status is(More)