[Design of non-dispersed infrared (NDIR) methane gas sensor].

A non-dispersed infrared (NDIR) methane gas sensors system based on infrared absorption spectrum theory was designed according to single light beam and double wavelengths technology. In the system, an infrared LED IRL715 serving as the light power, a absorptive gas cell with the function of dust-proof and damp-proof and a pyroelectric detector LIM-262 are composed of optical probe. Signal condition uses active filter circuit and differential amplifier, and binomial expression fits the relation curve between methane concentration and voltage, which realizes accurate detection of gas concentration. Experiment approved that the sensor system with good consistency and applicability can detect the range of 5% methane reliably and have 0.5% of the sensitivity, possessing the conditions for industrial applications initially.

[Electro-optic modulation based study on spectrum resolution of static Fourier transform spectrometer].

In the static interferometer system, the variable refractive crystal LiNbO3 with electro-optic modulation was used in static Fourier transform interferometer, where both sides load phase opposite modulation signal separately so to raise the spectrum resolution in the same size of the instrument by the increment of optical path difference. According to the derivation of the optical path difference function with refraction modulation, the maximum optical path difference was calculated and the spectrum resolution was analyzed to be 16.7 times previous one when the refraction modulation was 0.030 in the same size of interferometer. The simulation result indicated that the refractive modulation would be reduced when the wavelength increased, and the value of optical path difference will be bigger when the chi' increased. In actual detection process, because spectral region 500-1 100 nm is relatively narrow, the spectrum distortion by the wavelength change is not big and may be compensated through the demarcation. This method can increase the optical path difference without mechanical scanning, and possibly raises spectrum resolution of the static interferometer.

[Research on concentration of multi-component pollution gas based on SVM with kernel optimized by rough set].

This paper introduced the application of support vector machines (SVM) regression method based on kernel function optimized by the rough set in the infrared spectrum quantitative calculation. According to kernel function with the rough set classification's method, the spectrum data (characteristic wavelength section) is optimized. The kernel function leads support vector machines, and the SVM project the two-dimensional room to the multi-dimensional room, and calculate the concentration of every kind of gas in multi-component pollution gas. By using two kinds of typical spectrum data processing algorithm to make the contrast, the comparison of five kinds of gaseous mixture various proximate analysis is carried out, and when the spectrum separable rate is high, the predicted values of the three methods approach the normal value, and the average error is smaller than 0.13; but when the spectrum separable rate is low, the RS-SVM predicted value is more precise than the first two kinds. Experimental data show that the consequence is better when there are more testing types, and the precision and operation of this method is of more remarkable superiority.

[Methane optic fiber sensor network based on infrared spectrum absorption in coal mine].

Through analyzing the infrared absorption spectrum of methane, a multi-point optic fiber sensor network was designed based on the principle of light absorbing capability of gas which varies with gas concentration at its characteristic wavelength A distributed feedback laser diode (DFB LD) was used as the light source and an InGaAs PIN as the photodetector which features high sensitivity and low noise. Sixteen methane sensors were multiplexed in this system with space division multiple access technology (SDMAT), and the faint signals were processed by the filtering and amplifying circuit. All signals were gathered by the PCI data acquisition card, and finally, the signals were analyzed by the fast Fourier transform with software. The results showed that the sensitivity of every sensor reached 200 ppm (microg x mL(-1)), long-time accuracy and stability of all sensors could meet the practical demands, the response time of each sensor was less than 2 seconds and the detecting period was less than 32 seconds. By theoretical analysis, all sensors could be put in the mine at least 20 km from the ground, and the instruments could be applied to multi-point measurement at real-time in multiple occasions.

[Study on miniature static Fourier transform spectrometer used in laser warning receiver].

A miniature static Fourier transform spectrometer (MSFTS) as the component of coherent discriminating laser warning receiver (CDLWR) was designed in the present study by using a modified wedge interfering etalon (MWIE), a linear charge couple device (CCD) and a fast digital signal processor (DSP). The MSFTS possesses some advantages such as small volume, low cost, high speed, stable performance and good signal to noise ratio. MSFTS can detect the spectrum of HIPL, the short pulse width of laser is about 10 ns, and the spectrum scope is from 400 to 1 100 nm. The key element of MSFTS is MWIE which is composed of two triangle prisms, one of which is a right angle prism with two equal acute angles of 45 degrees, another prism has no right angle, one of the acute angles is 45 degrees, and another is slightly smaller than 45 degrees. The long sides of the two prisms were bonded by transparent glass glue, and the adhesive surface is plated with special material which serves as a beam splitter (BS). The incident laser will be split into two equal strength beams with continuously changing optical path difference, the two beams will interfere and form interferogram which will be focused by a cylinder as a line and transformed as s electronic signal by CCD. The electronic signal was processed by using a DSP, and finally we obtained the spectrum of the incident hostile laser by applying fast Fourier transform (FFT). We have established the experiment system of MSFTS, and used the system and the spectrometer Q8344A made by Advantest Company in Japan to measure the spectra of the seven lasers with different central wavelengths: 635, 650, 670, 780, 808, 850 and 980 nm. The measurement result shows that the worst wavelength resolution is 8. 845 nm at 1 100 nm, the best wavelength resolution is 1.170 nm at 400 nm, the relative average error of central wavelength is 0.269 nm, the absolute average error is 0.919 nm and signal-to-noise ratio of our experiment system is better than that of Q8344A.

[Analysis and experimental verification of sensitivity and SNR of laser warning receiver].

In order to countermeasure increasingly serious threat from hostile laser in modern war, it is urgent to do research on laser warning technology and system, and the sensitivity and signal to noise ratio (SNR) are two important performance parameters in laser warning system. In the present paper, based on the signal statistical detection theory, a method for calculation of the sensitivity and SNR in coherent detection laser warning receiver (LWR) has been proposed. Firstly, the probabilities of the laser signal and receiver noise were analyzed. Secondly, based on the threshold detection theory and Neyman-Pearson criteria, the signal current equation was established by introducing detection probability factor and false alarm rate factor, then, the mathematical expressions of sensitivity and SNR were deduced. Finally, by using method, the sensitivity and SNR of the sinusoidal grating laser warning receiver developed by our group were analyzed, and the theoretic calculation and experimental results indicate that the SNR analysis method is feasible, and can be used in performance analysis of LWR.

[Research on laser spectrum detecting technology based on static Mach-Zehnder interferometer].

It is the key content of laser warning to reliably and real-time detect the type and characteristic parameters of incident laser. Coherent detection technology detects the information based on the coherence of laser, and is a kind of effective detection technology. In order to detect the incident laser's spectrum, a kind of device for laser detecting and real time spectrum measurement was designed, which measures the laser spectrum on the bases of coherent detecting technology, Fourier optics and optical signal processing. Using compact and static Mach-Zehnder interferometer as the coherent detection components, it can restrain the background light efficiently. The non-scanning mechanical parts allow fast spectrum detection, and narrow laser pulse can be detected. The real-time signal processing is realized by DSP and multi-channel frame subtraction technology to wipe off the background light, detect the laser and measure its spectrum. The result indicates that, using Mach-Zehnder interferometer and multi-channel frame subtraction technology can realize the laser pulse detection, and improve the measuring precision efficiently; 10 ns laser pulse can be detected and the wavelength measuring error is less than 10 nm.

Cytotoxic effects and mechanisms of an alteration in the dose and duration of 5-fluorouracil.

5-Fluorouracil (5-FU) is the most routinely administered drug in the treatment of colon cancer. The main mechanism of the drug is not completely understood and its method of administration has been strongly disputed. A 24-hour infusion of 5-FU has clinically yielded better response rates and lower toxicities in comparison to bolus administration, but an exploration into possible mechanisms needs to be performed. Experiments were conducted with two 5-FU resistant cell lines where cytotoxicity, thymidylate synthase (T.S.) activity, thymidine kinase (T.K.) activity, DNA and RNA incorporation, and T.S. expression were contrasted between a 10 microM/24 hour administration of 5-FU (simulating continuous exposure) and a 100 microM/1 hour schedule (simulating bolus administration). After 6 days from the initial exposure, the 10 microM/24 hour schedule (schedule A) inhibited more cell growth than the 100 microM/1 hour regimen (schedule B) by more than 38% and 17% in the two cell lines. After the 6-day observation, schedule A inhibited twice as much T.S. activity as schedule B. Incorporation of [14C]-5-FU into DNA and total RNA was higher in cells exposed to schedule A in comparison to schedule B over the 6 days. T.S. expression and T.K. activity patterns were variable over time. Thus, the exposure of 10 microM/24 hour 5-FU results in superior cytotoxicity when compared to a 100 microM/1 hour regimen and its effectiveness may be explained mechanistically by T.S. activity and DNA and RNA incorporation.

Cloning and sequence analysis of tumor-associated gene hMMTAG2 from human multiple myeloma cell line ARH-77.

In order to look for the tumor-associated genes from human multiple myeloma (MM), a cDNA library of human multiple myeloma cell line ARH-77 was constructed with eukaryote expression vector pcDNA3.1(+). The length of inserted fragments in library was 1.2 kb in average. All clones in cDNA library were transferred in situ to nylon membrane, which was divided into eight equal parts (A-H) and cultured in LB medium to set up gene pools. The plasmids in cDNA library and in gene pools were extracted and NIH/3T3 cells were transfected respectively. By G418 screening and colonies counting, gene pool A was chosen for the second cycle transfection. After several cycles, a clone, A62-17, was obtained, which had significant transforming ability. The length of this clone was 993 bp. The RACE technique was used for rapid amplification of A62-17 5'-end. The full length of this sequence has 1300 bp and was named as hMMTAG2 gene. hMMTAG2 consists of 8 exons and codes for a polypeptide of 263 amino acids (the accession number in GenBank: AY137773). It was located at chromosome 1q42.13. hMMTAG2 had same transforming activities in NIH/3T3 cells as the clone A62-17, and the number of transformant foci was 6 folds more than the blank vector pcDNA3.1(+). The analysis of bioinformatics revealed that hMMTAG2 had many phosphorylation sites for several protein kinases, N-myristoylation sites and nuclear localization signals, so it may be a signal molecule in the nucleus.