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Abstract: Using the technology of tuneable diode laser absorption spectroscopy and the technology of micro-electronics, a fiber laser methane sensor based on C8051F410 is given. We use the DFB Laser as the light source of the sensor. By tuning temperature and driver current of the DFB laser, we can scan the laser over the methane absorption line, we realize the methane detection. It makes the real-time and online detection of methane concentration to be true, and it has the advantages just as high accuracy, immunity to other gases, long calibration cycle and so on. The sensor has the function of self-diagnose, the soft will alarm when the probe in a fault status, then it improve the dependence of the measurements. In coal mine safety, the proportion of gas accidents are improving continuously, Since for the coal mine safety, the personnel safety and the environment protection, it is very important to realize the real-time online detection of methane in coal mine. In this paper, some data that coming from the application of sensor in the field of coal mine is given. And we also do some analysis of the data. At last, according to the actual situation of the transducer in coal mine, we list some problems and the direction of further improvements. [Copyright &y& Elsevier]

Background and aims: It has been considered that the functional decline of renal vasoconstriction during senescence is associated with an alteration in renal α1adrenergic receptor (α1AR) expression. While alterations in renal angiotensin II receptor (ATR) expression was considered to have an effect on renal structure and function, until now little information has been available concerning α1-AR and ATR expression variations over the entire aging continuum. The present study was undertaken to examine the expression levels of α1-AR and ATR subtypes in renal tissue during the spectrum running from young adulthood, to middle age, to the presenium, and to the senium. Methods: Semiquantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR) and Western Blot were used to quantify the messenger RNA (mRNA) and protein levels of α1-AR and ATR subtypes in renal tissue in 3-month-old (young adult), 12-month-old (middle age). 18-month-old (presenium) and 24-month-old (senium) Wistar rats. Results: α1-AR expression decreased gradually with aging: it was decreased during middle age, the presenium and the senium, compared, respectively, with young adult values (p<0.01), and there was a significant decline both in the presenium with respect to middle age and in the senium with respect to the presenium. α1B-AR and α1D-AR expression were unmodified during senescence. AT1R expression was unaffected by aging during young adulthood and middle age, but exhibited a remarkable downregulation in the presenium and senium periods (p<0.01). AT2R expression was markedly increased in the senium (p<0.01). Conclusions: These results suggest that there are considerable variations in the expression levels of renal α1-AR and ATR subtypes during aging. α1A--AR expression downregulation may account for the reduced reactivity of renal α1-AR to vasoconstrictors and to renal function decline in the senium. Both the downregulation of AT1-R and the upregulation of AT2-R may be influential in maintaining normal physiological renal function during aging. [ABSTRACT FROM AUTHOR]