Multi-phase-driven split-word-line ferroelectric memory without plate line
A working methodology bypasses the conventional cell plate line (PL), mitigating its disadvantages. The methodology utilizes split word lines (SWLs), driven by multi-phased voltage signals. In this scheme there is no need for PL and additional elements, and fabrication is simple and compatible with downscaling of cell area.
A 3.3-V, 4-Mb nonvolatile ferroelectric RAM with selectively driven double-pulsed plate read/write-back scheme
This paper presents, for the first time, a 4-Mb ferroelectric random access memory, which has been designed and fabricated with 0.6-/spl mu/m ferroelectric storage cell integrated CMOS technology. In order to achieve a stable cell operation, novel design techniques robust to unstable cell capacitors are proposed: (1) double-pulsed plate read/write-back scheme; (2) complementary data preset reference circuitry; (3) relaxation/fatigue/imprint-free reference voltage generator; (4) open bitline cell array; (5) unintentional power-off data protection scheme. Additionally, to improve cell array layout efficiency a selectively driven cell plate scheme has been devised. The prototype chip incorporating these circuit schemes shows 75 ns access time and 21-mA active current at 3.3 V, 25/spl deg/C, 110-ns minimum cycle. The die size is 116 mm/sup 2/ using 9 /spl mu/m/sup 2/, one-transistor/one-capacitor-based memory cell, twin-well, single-poly, single-tungsten, and double-Al process technology.
Exopolysaccharide biosynthesis and related enzyme activities of the medicinal fungus, Ganoderma lucidum, grown on lactose in a bioreactor
Exopolysaccharide (EPS) production and biosynthesis were studied in Ganoderma lucidum, a fungus used in traditional Chinese medicine, grown with lactose in a bioreactor. β-Galactosidase activity, which implies the existence of a lactose permease system, was induced by lactose. Lactose feeding also increased α-phosphoglucomutase activity and EPS accumulation but decreased phosphoglucose isomerase activity and lactate concentration in the culture broth. A maximum cell density of 22 g l−1 and EPS at 1.25 g l−1 were obtained in fed-batch bioreactor culture.