M-Sequence Modulated Microwave Level Meter

Abstract

An extremely sensitive, accurate and simple microwave level meter has been developed. This level meter consists of a continuous wave radar in which carrier is modulated by the M-sequence (Maximal-length-sequence).Employing two M-seq. which are the same in code but generated by the slightly different clock frequencies, the implementation of the crosscorrelation between the received and the reference signals can be simple. This radar successfully gains the sensitivity and suppresses the noise. Moreover, the quantization error of this radar can be designed smaller than the conventional FMCW (Frequency-Modulated-Continuous-Wave) microwave radar. The principle of this microwave level meter is studied and its design criteria are described.This microwave level meter is useful in the case that exclusive performance in terms of sensitivity and accuracy is required for the crucial measurement conditions in the environment such as the iron and steel making process where dust and flare may make it difficult to employ the laser beam or supersonic as sensing waves. The application of the Mseq. modulated microwave level meter is discussed in the experiments measuring the metallurgical slag and the molten metal levels.In the prototype microwave level meter, the carrier frequency is 10GHz, the output power 40mW, the clock frequencies driving the two M-sequence generators about 220MHz, the difference of the two clock frequencies 5.4 kHz or 10kHz, and the lengths of the M-seq. 127bit or 1,023 bit. The water-cooled horn antennas with the gain of 17dB are used.

Light‐induced oxidation of iron atoms in a photosensitive nitrile hydratase

“…mm/s (species A) and a quadrupole splitting of 0.36 mm/s (species B) are exceptionally low values compared with those of other non-heme irons hitherto observed in various proteins, according to our recent survey of Mossbauer parameters. This fact and the absorption spectra of this enzyme [2] manifest a possibility of the iron atoms in this :!nzyme being integrated in an unreported structure. From Massbaucr parameters, species A can bc assigned to either low spin ferrous (Fe?')…”

“…The supernatunt wrs used as the crude cell-free extract. The crude cell-free extract was purifcd by ammonium sulfate fractionation (40-60% saturation), ion-cxchungc column cbromrutography (Whatman DE-52) and hydrophobic column chromatography (Toyopearl HW-6SC) as described previously [2]. The NHux fractions wcrc co].…”

“…The inactive and uctive NHase samples (native) containing 14.5 bg Fe each (cquivalcnt to about 6 mg NHasc) were prepared by the method previously described [2]. and placed in pharmuccutical cnpsules.…”

“…We presumed that this change in absorption is an indication of the two iron atoms incorporated per NHase molecule as non-heme irons [2], making some kind of electronic and/or structural change upon this photoactivation process. Thus we have undertaken the present investigation to clarify changes in the state of iron atoms in this enzyme,…”

“…Its catalytic activity is enhanced by an exposure to near ultra-violet light, and this activation process (Eq. 2) is accompanied by a drastic change in absorption spectrum [2]. R-CN + Hz0 -R.-CONH: (Eq.…”