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High luminescence intensity is crucial for realizing luminescent temperature sensing with a large signal-to-noise ratio. In this work, the temperature sensing behavior of Ca1-xNaxMoO4:Yb3+,Er3+ with intense green up-conversion luminescence was studied. It has been demonstrated that the single-band green emission was dependent on the Yb3+-MoO42- dimer sensitization as well as the low multi-phonon relaxation rate of 4S3/2 → 4F9/2. In addition, it was found that the uncorrected thermometer could not accurately measure temperature due to thermal effects. A simple method for calibration of up-conversion temperature sensing was reported. Due to high luminescence intensity and temperature sensitivity, Ca1-xNaxMoO4:Yb3+,Er3+ is a promising candidate for up-conversion temperature sensing.

Using off-axis integrated cavity output spectroscopy, named OA-ICOS, the absorption spectrum of CO2 at 4.32 μm is recorded by using a quantum cascade laser (QCL). The concentration of the three isotopologues 16O12C16O, 16O13C16O and 16O12C18O is detected simultaneously. The isotope abundance ratio of 13C and 18O in CO2 gas can be obtained, which is most useful for ecological research. Since the ambient temperature has a serious influence on the output wavelength of the laser, even small temperature variations seriously affect the stability and sensitivity of the system. In this paper, a wavelength locking technique for QCL is proposed. The output of a digital potentiometer integrated in the laser current driver control is modified by software, resulting in a correction of the driving current of the laser and thus of its wavelength. This method strongly reduces the influence of external factors on the wavelength drift of lasers and thus substantially improves the stability and performance of OA-ICOS as is demonstrated with long-time measurements on CO2 in laboratory air.

The change of stable isotope ratio of carbon dioxide (δ13CO2) in respiratory gases of patients before and after taking medicine can be used to judge whether Helicobacter pylori exists in patients’ intestines and stomach. The 4.3 μm band of blackbody radiation source and infrared dual path structure are selected for measurement, the incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) technology was used to change the structure of the light path on one side of 13CO2 to make sure that the absorption intensity of 13CO2 and 12CO2 was in the same order of magnitude. The influence of different types of optical cavity, coating method of lens and reflectivity of mirror on effective optical path were compared in this article and the effective optical path length was the largest when the semi-stable cavity with 90% reflectivity and Ge coating material was used. The standard deviation of the measurement results was 0.191‰, which met the requirements of the precision and accuracy of the measurement index in medical detection. The system had the advantages of high precision, small volume, and accurate measurement results, which is of great significance for medical auxiliary detection.

Methane (CH4) and acetylene (C2H2) are important bioscience and chemical gases. The real-time monitoring and analysis of them have important research value in industrial process control. The time-sharing scanning assisted wavelength modulation spectroscopy (WMS) technique is developed for real-time and simultaneous detection of CH4 and C2H2. This system involves two near-infrared distributed feedback (DFB) lasers and a compact multipass cavity with an effective optical path of 52.2 m. The selected strong absorption lines of methane and acetylene are located at 6046.96 cm-1 and 6531.7 cm-1, respectively. The experiment environment is conducted at room temperature 23 °C and pressure 760 Torr. The sensor performance, including the minimum detection limit (MDL) and the stability, was improved by eliminating the influence of light intensity fluctuation using the WMS-2f/SAW technique. Allan deviation analysis indicates that a MDL of 0.1 ppm for CH4 and 0.2 ppm for C2H2 are achieved with 1-s integration time. And the instrument response time is about 44 s through the continuous analysis of standard gases. This sensitive, simple, reliable, and lowcost dual-gas sensor is very suitable for applications in the field environment, chemical process, and many other gas-phase analysis areas.

BACKGROUND: It was observed that the number and function of endothelial progenitor cells (EPCs) decreased sharply in the progression of multiple organ dysfunction syndrome (MODS), and it may be the main pathogenesis for MODS. We aim to perform autologous transplantation of EPCs on animal models of MODS to investigate whether EPCs might be used to prevent MODS caused by severe sepsis. METHODS: A total of 60 pigs were randomly divided into three groups: subjected to hemorrhagic shock + resuscitation + endotoxemia only (MODS group); performed autologous transplantation of EPCs after hemorrhagic shock + resuscitation + endotoxemia (transplantation group); and control group. Mononuclear cells of animals of the transplantation group were isolated by density-gradient centrifugation for ex vivo expansion, and the six-passage EPCs labeled with 5-carboxyfluorescein diacetate succinimidyl ester were autologously transplanted at a density of 1 × 10(7) cells/kg body weight at the 24th hour after endotoxemia. The function of important organs was monitored continuously to assess the effects of autologous transplantation of EPCs on MODS. RESULTS: All animals of the MODS group developed MODS (100%), and 17 (85%) of 20 animals died because of MODS; the incidence of MODS and mortality rate in the transplantation group were 45% (9 of 20 pigs; p < 0.01) and 35% (7 of 20 pigs; p < 0.01). In transplantation group, the incidence of pulmonary dysfunction, cardiac dysfunction, hepatosis, and renal dysfunction were 40%, 10%, 5%, and 15%, respectively. The capillary densities of important organs, including the heart, liver, kidney, intestine, and lung, after autologous transplantation of EPCs were significantly higher than those in the MODS group (p < 0.01). CONCLUSION: Autologous transplantation of EPCs could migrate to injured organs and induce angiogenesis to restore blood flow that could improve the function of important organs. It could prevent the incidence of MODS and reduce mortality rate caused by trauma and severe sepsis. Autologous transplantation of EPCs would be a novel, cell-based, vascular endothelium-targeted therapeutic strategy for MODS.

To monitor the velocity of industrial exhaust gas continuously,a parallel double-path flow velocity measurement system was designed,and the related theories on measuring the velocity of stack gas flow was studied based on the light scintillation.A simple phase-screen technique was used to analyze the light scintillation in a turbulent medium,and the expression of optical scintillation cross-correlation was obtained which is used to measure stack gas flow velocity.The path-weighting function of the mean velocity was given.The numerical simulation carried on path-weighting function indicates that it has axially symmetric distribution as Gaussian line shape,and the central velocity of the stack makes greater contribution.The impact of light source spectrum on path-weighting in principle was analyzed,and the preliminary experiments show that,although because the light source spectrum has a certain bandwidth,the path-weighting function has changed,the distribution is still axially symmetric.Based on the path-weighting function,the space distribution of the gas flow velocity in stack can be calculated.

Aiming at the problems in unknown environment for mobile robots map building, a method combined monocular vision and DGSOM(Dynamic Growing-SOM) Algorithm is proposed. The method first uses a monocular camera to collect environment images, after treatment with monocular vision processing technology, environmental information samples for DGSOM algorithm are obtained from image information, and then they can be used as neural network training samples, thus the topologic map that describes the environment information is generated with a few SOFM neurons. The experimental result shows that autonomous mapping for robot using a combination of monocular vision and DGSOM algorithm is feasible, and the robot can realize environment mapping automatically.

With the development of the intelligent substation technology, the centralized protection attracts more and more attention of Chinese scholars. Due to the implementation of IEC61850, the development of the high-speed Ethernet, and the advanced performance of computer hardware, the centralized protection becomes a possible choice. Centralized protection simplifies the traction substation secondary wiring, and realizes real time data sharing. It avoids the repeated configuration of hardware, and reduces the space required for the installation of protection devices. Under the consideration of these advantages, the centralized protection will be the main trend for micro-computer protections for traction substations. Compared with and traditional protection, this paper discusses the schemes for the centralized protection for the hybrid dual redundant star network is discussed, and illustrates the design and reliability for these schemes.

We report the first application of gas total emission using a DFB diode laser for gas concentration measurements combined with two LEDs for gas velocity measurements. In situ gas total emissions and particle density measurements in an industrial pipeline using simultaneous tunable diode laser absorption spectroscopy (TDLAS) and optical scintillation cross-correlation technique (OSCC) are presented. Velocity mean values obtained are 7.59 m/s (OSCC, standard deviation is 1.37 m/s) and 8.20 m/s (Pitot tube, standard deviation is 1.47 m/s) in a steel plant pipeline for comparison. Our experiments demonstrate that the combined system of TDLAS and OSCC provides a new versatile tool for accurate measurements of total gas emissions.

Sensitive detection of hydrogen sulfide (H2S) has been performed by means of wavelength modulation spectroscopy (WMS) near 1.578 μm. With the scan amplitude and the stability of the background baseline taken into account, the response time is 4 s for a 0.8 L multi-pass cell with a 56.7 m effective optical path length. Moreover, the linearity has been tested in the 0–50 ppmv range. The detection limit achievable by the Allan variance is 224 ppb within 24 s under room temperature and ambient pressure conditions. This tunable diode laser absorption spectroscopy (TDLAS) system for H2S detection has the feasibility of real-time online monitoring in many applications.

Theoretical analysis for an online measurement of the stack gas flow velocity based on the optical scintillation method with a structure of two parallel optical paths is performed. The causes of optical scintillation in a stack are first introduced. Then, the principle of flow velocity measurement and its mathematical expression based on cross correlation of the optical scintillation are presented. The field test results show that the flow velocity measured by the proposed technique in this article is consistent with the value tested by the Pitot tube. It verifies the effectiveness of this method. Finally, by use of the structure function of logarithmic light intensity fluctuations, the theoretical explanation of optical scintillation spectral characteristic in low frequency is given. The analysis of the optical scintillation spectrum provides the basis for the measurement of the stack gas flow velocity and particle concentration simultaneously.

Tunable diode laser absorption spectroscopy (TDLAS) is often used to detect gas concentrations in many fields. But because of the variation of ambient temperature, the measured harmonic signal amplitudes are affected and may lead to the monitoring errors. The impact of temperature on the measurement as well as the temperature compensation method is emphasized. So in order to modify the inversion results and adapt industrial measurement, combustion diagnostics, the numerical fitting empirical modified equation and theoretical modified equation from HITRAN database are discussed and compared in this paper. In experiment, the 21% oxygen as the safety monitoring gas and absorption wavelength at 760.77 nm are employed. Meanwhile, the first harmonic signals are also used to decrease the laser intensity fluctuations. We thus obtained the unmodified and modified results with the tube furnace in the temperature range 300–900 K (interval 50 K). Experimental results show that these two modified methods have some effective influence on the temperature changes and can be applied to gas monitoring correction to improve the accuracy and feasibility of the TDLAS technology. In addition, the methods also provide evidence for the real-time gas monitoring in the application of combustion diagnosis.

CO is an indicative gas of coal spontaneous combustion warning and mine production safety instruction, whose detection process generally requires fiber long-haul transmission. However, currently, the communication fiber windows are mainly in the near-infrared band, so it is very significance to realize highly sensitive CO detection at near-infrared band. Tunable diode laser absorption spectroscopy (TDLAS) technology has advantages of high sensitivity, high resolution, fast response ability and no-contact, which has been widely used in air pollution monitoring, industrial and agricultural production process control, and many other fields. Long-path multi-pass cell can effectively improve the TDLAS detection capabilities, at the same time, the whole system is more compact. In this paper, 1566.64 nm DFB laser and the novel multi-pass cell with an optical path 56.7 m are used to detect different CO concentrations in long-term, while the system stability and linearity are analyzed. In addition, the detection limit is 0.25 ppmv with 30 s integration time by calculating the Allan variance. It means that we have primarily achieved highly sensitive detection of CO in the near-infrared bands.