[The Study of Spectral Characteristic of Coal Ash from Different Sources with Laser-Induced Breakdown Spectroscopy]

The samples with different carbon content are collected for quantitative analysis. One of the normal methods is the ignition of different coals according to the notice of fast ashing method instead of collecting coal ash in boiler. But there are some differences between fast ashing method in laboratory and actual boiler. It is necessary that the spectral deviation of coal ash from these two sources is studied as a guidance of quantitative analysis in carbon content. In present work, the intensity of the characteristic lines and plasma temperature were compared with different carbon content from these two processes. As a result, Fe, Mg, Al line strength of ash with fast ashing method is stronger and plasma temperature is lower than coal ash in boiler. Principal component analysis was processed, the results show that the difference of Fe, Mg, Al and Si content is the primary factor, and minerals in coal ash with fast ashing method may influence the spectral characteristic. The influence of mineral elements and mineral content on spectra for quantitative analysis with fast ashing method should be noticed.

[Rapid Measurement of Carbon Dioxide with Laser-Induced Breakdown Spectroscopy Based on Atomic and Molecular Spectrum].

With the rapid development of economy and industrialization, global warming is becoming the most serious sensitive global climate issues, which causes the rising of sea level and many other negative effects. The cause of global warming is the emission of greenhouse gases and carbon dioxide is the main component of greenhouse gases. The control of CO2 emssion is beneficial to addressing gobal climate change and environmental degradation. Therefore, it's important to develop a rapid detection of CO2 for accurate control. There are amounts of methods to detect CO2 at present, including titration, electrochemical method, gas chromatography, infrared absorption spectroscopy and so on, however, t they still have the deficiency for online monitoring in industrial field. laser induced breakdown spectroscopy (LIBS), which is developing rapidly in recent few decades, is a detecting technology with characteristics of time-saving and synchronous measuring of multicomponent. What's more, there is no need for sample pretreating. To develop the online monitoring technique of CO2 emission in the industrial field, LIBS was employed to measure CO2 in this study. The mass flow controller was used to adjust the flow of high purity CO2 and N2 to obtain mixed gas with different CO2 concentrations. The mixed gas was firstly mixed in an air mixing chamber for thorough mixing and then sent to the sample cell for LIBS measurement. The evolution of C atomic spectral line and CN molecular band with different delay times were being studied, which demonstrated parts of CO2 react with air ambient to form CN molecular during the plasma generation, the CN molecular band should be taken into consideration for quantitative analysis, and the parameters were optimized for synchronous measurement of C line and CN band: 800 ns was the optimal delay time. During the plasma generation, many factors in the plasma may interact with others, the analysis index had close relationship wih serval measuring parameters. With the consideration of the effect of C, CN and the self-absorption in high concentration, multivariate calibration method was employed to establish calibration models of CO2. The results showed that the correlation coefficients R2 and the slope were 0.978 and 0.981, respectively. Compared with calibrated with single factor, the multivariate method improved the reliability of the model. What's more, the feasibility of the application of LIBS to measure CO2 rapidly was proved.

[Influence of C-Fe Lines Interference Correction on Laser-Induced Breakdown Spectroscopy Measurement of Unburned Carbon in Fly Ash].

In coal-fired plants, Unburned carbon (UC) in fly ash is the major determinant of combustion efficiency in coal-fired boiler. The balance between unburned carbon and NO(x) emissions stresses the need for rapid and accurate methods for the measurement of unburned carbon. Laser-induced breakdown spectroscopy (LIBS) is employed to measure the unburned carbon content in fly ash. In this case, it is found that the C line interference with Fe line at about 248 nm. The interference leads to C could not be quantified independently from Fe. A correction approach for extracting C integrated intensity from the overlapping peak is proposed. The Fe 248.33 nm, Fe 254.60 nm and Fe 272.36 nm lines are used to correct the Fe 247.98 nm line which interference with C 247.86 nm, respectively. Then, the corrected C integrated intensity is compared with the uncorrected C integrated intensity for constructing calibration curves of unburned carbon, and also for the precision and accuracy of repeat measurements. The analysis results show that the regression coefficients of the calibration curves and the precision and accuracy of repeat measurements are improved by correcting C-Fe interference, especially for the fly ash samples with low level unburned carbon content. However, the choice of the Fe line need to avoid a over-correction for C line. Obviously, Fe 254.60 nm is the best

[Study of laser energy in multi-element detection of pulverized coal flow with laser-induced breakdown spectroscopy].

The logical range of laser power density and optimum laser power density were explored for multi-element analysis of pulverized coal flow with laser-induced breakdown spectroscopy in the present paper. The range of laser energy was chosen from 20 to 160 mJ in the experiment. Pulverized coal less than 200 microm in diameter of particles fell freely through feeder outlet and the rate of flow was controlled by screw feeder. Emissions were collected with pulse laser at 1 064 nm focusing on pulverized coal flow and plasma was generated. The intensity and cause of fluctuation of emission spectra at various laser energy levels were studied. A suitable range of laser power density is from 14.4 to 34.4 GW x cm(-2), and the optimum laser power density is 19.5 GW x cm(-2) for the determination of pulverized coal flow with LIBS.

[Influence of laser energy on measurement of unburned carbon in fly Ash particle flow].

The fly ash particle flow was produced by a screw feeder and then ablated by a pulse laser to create plasma. The emission spectra of fly ash were detected by laser-induced breakdown spectroscopy. The present paper focused on the influence of laser energy on the measurement of unburned carbon. Seven groups of pulse laser in the range of 40 to 130 mJ were used to ablate the fly ash particle flow. The results show that the carbon line intensity is increased linearly with the increases in laser energy, but the SNR of carbon line increases in the range of 40 to 90 mJ and then trends to saturation, while the elimination rate of false data decreases. In this experiment, laser energy ranging from 90 to 100 mJ can enhance the plasma emission signal and improve the true spectral data of fly ash particle flow. So laser energy has close correlations with the ablation of the particle flow and the carbon line intensity. Reasonable laser energy is good for the effective ablation of the fly ash particle flow to get plasma spectra signals with good SNR.

[The study on the laser-induced breakdown spectroscopy properties of compound fertilizer with different physical forms].

In order to study the mechanism of laser-induced breakdown spectroscopy for detecting the chemical components content of compound fertilizer in detail, two physical forms of compound fertilizer samples (powder and granular) were used for this study. The authors analyzed the laser-induced breakdown spectroscopy properties of samples with different physical forms made under different preparation pressure. And the spectral characteristics and plasma characteristics of N,P and K in the powder and granules made under the preparation pressure of 0, 0. 5, 2, 4, and 6 MPa, respectively were compared experimentally. The experiments results showed that the spectral characteristics of the two forms have obvious difference when the pressure is small and the grain samples have significant higher line intensity than those of the powder samples. With the increase in the pressure, the difference in the plasma characteristics between these two physical forms was reduced, and all the characteristic spectral lines intensity of the same physical form samples increases firstly and reduces afterward.

[Real-time, quantitative analysis of multi-elements in liquid steel by LIBS].

The technique of laser induced breakdown spectroscopy (LIBS) was applied to analyze the composition of liquid steel. The results of research indicated that oxidation of liquid steel on the surface could be avoided because the argon and the plasma signal was enhanced at the same time. The surface of liquid steel was excited by high-energy pulse laser and plasma was formed in argon atmosphere. The spectral signal was collected with a multi-channel CCD spectrometer when the plasma cooled off and relevant information about the composition of samples was obtained. The characteristic spectral lines of analyzed elements were selected according to the selecting principle of line in LIBS and the calibration curves of major alloying elements Mn, Si and Cr were constructed. The degrees of linear fitting were all more than 0. 925 and the limit of detection of Mn, Si and Cr were 75.7, 23.8 and 724.5 microg x g(-1), respectively.

[Application of wavelet transform in laser-induced breakdown spectra compression].

A method based on the wavelet transform (WT) was developed for the compression of laser-induced breakdown coal spectral data. By studing the impacts of main parameters such as the order of db wavelet, decompose level and threshold method on compression performance, it can summarize the compression parameter selection rule and select the proper compression scheme. The scheme was evaluated by compression scores and relative deviation of each spectral line between original and reconstructed. By choosing proper parameters for channel 1, channel 2 and channel 5 of LIBS spectrum of coal sample (No. 1-No. 8), the restore score RS and compress score CS are respectively 81%-92.11% and 79.02%-92.07%, with the spectral line relative deviation under 5%. It indicates that the storage space is reduced while the main characteristic of original spectrum is maintained. The result shows that this method is very effective.

Bipolar transurethral resection in saline system versus traditional monopolar resection system in treating large-volume benign prostatic hyperplasia.

OBJECTIVES: We report our prospective clinical result of transurethral resection in saline (TURIS) versus monopolar transurethral resection of the prostate (TURP) system in treating large-volume benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: Patients with BPH (volume >50 ml) were enrolled in the study. An intravenous device was used for serum sodium and hemoglobin tests to monitor the alteration. All acute complications were noted. Patients were followed up for at least 6 months. RESULTS: Forty patients were randomized into two groups. Follow-up data were compared with baseline. The decline in serum sodium postoperatively was smaller in the TURIS group (6.9 +/- 0.7 vs. 14.8 +/- 1.8 mM, p = 0.001). Hemoglobin only dropped by 1.4 g/dl in the TURIS group, whereas it dropped by 2.5 g/dl in the TURP group (p = 0.001). The TURIS system showed a better resection rate (0.64 vs. 0.52 g/min, p = 0.001). Total acute complication rate was 8 of 19 (42%) in the TURP arm and 4 of 21 (19%) in the TURIS arm. The catheter was removed sooner (2.5 vs. 3.4 days) and hospitalization time was less (3.0 vs. 4.2 days) in the TURIS group. The mean improvement in the International Prostate Symptom Score and maximum urinary flow rate at 6 months was comparable in the two groups. CONCLUSION: The TURIS system demonstrated superior safety in treating large-volume BPH and had a similar efficacy to TURP in short term.

[Impact of laser energy on measurement of fly ash carbon content].

A laser induced breakdown spectroscopy-based apparatus for the analysis of element, employing a 532 nm laser and a multi-channel optical spectrometer with a non-intensified CCD array, has been built and tested. It was applied to analyze the carbon content of coal fly ash. Seven groups of pulse laser in the range of 35 to 98 mJ were used to ablate the fly ash samples. The electron densities and plasma temperatures with different laser energy were determined, and the influence of laser energy on the intensity of analysis carbon lines was also analyzed. The results show that carbon line intensity increases slowly with the increase in laser energy in the range of 35 to 46 mJ, and increases fast in the range of 46 to 78 mJ, then trends to saturation and has a little drop. At the same time, air breakdown has increased significantly, and has an obvious effect on sample plasma. Furthermore, the electron density and plasma temperature increase with the laser energy until 78 mJ and then begin to decrease. It indicates that a proper laser energy can enhance the plasma emission signal, and avoid the negative impact of air breakdown that prevent the pulse laser from reaching the surface of sample and ablating it. In this experiment situation, the measurement accuracy of the carbon line can be improved.

[Investigation on the delay time of coal experiment by laser-induced breakdown spectroscopy].

Laser-induced breakdown spectroscopy is a new technology of elementary analysis, and it will be used in coal analysis. The delay time of signal is an important parameter of spectral analysis. A LIBS system was set up and three kinds of coal (Jiangxipingxiang coal, Shanxixishan coal and Guizhoupingzhai coal) were chosen for this investigation. The spectra in the range of 240 to 250 nm and 275 to 290 nm of the each three coal samples are shown and they record several spectral lines of components such as C, Mg and Si according to the NIST database. The temporal evolution of SNR of spectral line was obtained, and the value of SNR increased with the time delay, then decayed. The temporal evolution of SNR was different as the coal, element and spectral line differs. Finally, optimum delay time of each spectral lines of elements in the coal samples was calculated according to the biggest value of signal-to-noise ratio, and the relation between the characteristic of coal, element, spectral line and the op timum delay time was analyzed.

High-Tech Acupuncture for Prevention of Lifestyle Diseases-A Sino-Austrian Cooperation Research Protocol on Heart Rate Variability.

BACKGROUND: Acupuncture can not only be used for well-known diseases, but also for so-called modern lifestyle-related diseases. Using innovative methods like e.g. new analyses of heart rate variability (HRV), it is also possible to investigate diseases like burnout syndrome, ie., qi deficiency in Chinese medicine (CM). OBJECTIVE: The main object of this research protocol is to perform research on the relationship of burnout syndrome and heart rate (HR) and HRV. METHODS: A total of 175 patients with burnout syndrome (qi deficiency syndrome) in five groups and 35 healthy volunteers will be investigated. Based on random numbers generated by computer and concealed in opaque envelops, the patients will be assigned to four acupuncture groups using Zusanli (ST 36) acupuncture stimulation, Guanyuan (CV4) acupuncture stimulation, both points, and both points with Streitberger device respectively, and a moxibustion group using both points mentioned above, with 35 cases in each group. Altogether four different experiments are planned. Experiment 1 includes 70 subjects and is a comparison between a burnout group and a control group (healthy volunteers). The evaluation parameters are different scores and indices of HR and HRV. Experiment 2 includes 140 subjects and compares the efficacy of different acupuncture points. In experiment 3 (105 subjects), acupuncture and moxibustion should be compared to healthy volunteers. Experiment 4 (70 subjects) investigates the long-term therapeutic effects of acupuncture and moxibustion on the scores of qi deficiency and HR/HRV in qi deficiency patients. In both the acupuncture and moxibustion groups, a total of 10 treatments will be performed. CONCLUSIONS: The joint research aims at the scientific evaluation of CM, mainly in the field of HRV. This parameter could be a very good indicator of the state of health and can be inflfluenced by different acupuncture methods, as shown in the past.