High-Precision and Real-Time Measurement of Water Isotope Ratios Based on a Mid-Infrared Optical Sensor.

A compact spectrometer based on a mid-infrared optical sensor has been developed for high-precision and real-time measurement of water isotope ratios. The instrument uses laser absorption spectroscopy and applies the weighted Kalman filtering method to determine water isotope ratios with high precision and fast time response. The precision of the measurements is 0.41‰ for δ18O and 0.29‰ for δ17O with a 1 s time. This is much faster than the standard running average technique, which takes over 90 s to achieve the same level of precision. The successful development of this compact mid-infrared optical sensor opens up new possibilities for its future applications in atmospheric and breath gas research.

Line positions and effective line strengths of trans-HONO near 1280 cm-1.

The measurement of the line positions and effective line strengths of the ν3 fundamental band of trans-nitrous acid (trans-HONO) near 1280 cm-1 (7.8 µm) by tunable laser absorption spectroscopy (TLAS) utilizing a room temperature continuous-wave quantum cascade laser (cw-QCL) was reported. The effective line strengths of 30 well-resolved trans-HONO absorption lines in the range of 1279.8-1282.2 cm-1 were determined using the HONO line strength at 1280.3841 cm-1 as a scale. The maximum measurement uncertainty of 7.64% in the line strengths is mainly determined by the uncertainty of the referenced line strength, while the measurement precision of the line positions is better than 5.56 * 10-3 cm-1. The line positions and strengths of the trans-HONO absorption lines obtained in this work provide a reference for continuous gas monitoring and analysis of the sources and sinks of atmospheric HONO.

Nonthermal plasma coupled with liquid-phase UV/Fe-C for chlorobenzene removal.

Catalyst poisoning problems limit the application of gas-solid non-thermal plasma (NTP) catalyzed decomposition of chlorinated volatile organic compounds (Cl-VOCs). To mitigate the catalyst deactivation, catalyst iron-loaded activated carbon (Fe-C) was added to the UV-activated liquid phase downstream of the NTP reactor (NTP + UV/Fe-C(L)) for the degradation of chlorobenzene (CB) in this study. The CB removal efficiency and mineralization efficiency (MR) of NTP + UV/Fe-C(L) were up to 94% and 68%, respectively, which were increased by 39% and 30% compared with the single NTP system. Compared with the conventional gas-solid NTP + UV/Fe-C(S) system, the stability of the NTP + UV/Fe-C(L) system was significantly improved due to the dissolved organic intermediates and low residuals on the catalyst surface. Reactive oxygen species ·OH and ·O2- dominated the decomposition of CB in the liquid phase, and with the help of UV, much more ·OH and ·O2- were produced by Fe-C catalytic O3. In addition, Fe-C improved the removal of CB by increasing its absorption mass transfer coefficient from 0.0016 to 0.0157 s-1. The degradation pathway of CB in the NTP + UV/Fe-C(L) system was proposed based on the detected organic intermediates. Overall, this study provides a new tactic to solve the catalyst poisoning problem in the NTP catalytic oxidation of Cl-VOCs.

In situ measurement of water vapor isotope ratios in air with a laser-based spectrometer.

Simultaneous measurement of H217O/H216O, H218O/H216O, and HDO/H216O in air with a compact spectrometer based on a mid-infrared distributed feedback (DFB) laser was described. The obtained mixing ratios of H216O, H217O, and H218O agreed reasonably well with those measured by a hygrometer. The precision and repeatability of the spectrometer were analyzed. Indoor air tests demonstrated that its 220-s precision was 0.08 ‰, 0.06 ‰, and 0.14 ‰ for δ18O, δ17O, and δ2H respectively. The measured values of δ18O, δ17O, and δ2H in indoor air were highly correlated with the water vapor mixing ratios. The compact spectrometer provides in situ measurements of water vapor isotopes with high precision and fast time response, which opens new possibilities for its application in atmospheric and hydrological research in the future.

Dielectric barrier discharge coupled with Fe2+, Mn2+ and Cu2+ scrubbing for toluene removal.

By-product ozone emission is one of the challenges for applying dielectric barrier discharge (DBD) technology for volatile organic compounds (VOCs) removal. In this study, a DBD reactor followed by a wet scrubber (WS) containing a solution of metal ions (Fe2+/Mn2+/Cu2+) was used to reuse ozone for further oxidation of typical VOC toluene. Compared with the degradation effect of the DBD reactor alone, DBD coupled WS/iron system not only improved the toluene removal efficiency but also significantly reduced the ozone emission. The ozone removal efficiency reached as high as 98% in the DBD coupled WS/Fe2+ system. Electron paramagnetic resonance (EPR) tests showed that ozone was converted into radicals such as hydroxyl radicals in Fe2+ and Cu2+ solution, which further oxidized toluene in WS/iron. Quenching experiments showed that the contribution for toluene degradation by radicals was up to 75% and 62% in Fe2+ and Mn2+ reactor, respectively. This study demonstrates that the DBD coupled WS system has the potential to be an environmentally friendly technology for gaseous VOCs removal.

[Clinic analysis of 16 patients of craniocerebral trauma with Labbé vein injury].

OBJECTIVES: To study the mechanism of Labbé vein injury, and its effect on traumatic cerebral infarction and prognosis in patients of craniocerebral trauma. METHODS: The clinic imageology and data of 16 patients of craniocerebral trauma with Labbé vein injury approved intraoperatively from June 2006 to February 2009 were analyzed. To compare the effect of the intraoperative finding of Labbé vein damage and blood vessel treatment on traumatic cerebral infarction, and to analyze the traumatic cerebral infarction size and prognosis. RESULTS: All the 16 patients had acute subdural hematoma and(or) intracerebral hematoma. And 15 of all the 16 patients with Labbé vein injury suffered from skull fractures. All patients accepted hematoma cleaning and intracranial decompression procedure by removing skull. The preoperative Glasgow coma scale (GCS) were as following: 5 patients being between 9 - 12, 7 patients being between 6 - 8 and 4 patients being between 3 - 5. Eight patients had cerebral hernia before operations on admission, and among them, 3 patients had corectasis of both sides and 5 patients had corectasis of only one side, the other 8 patients had no corectasis. Postoperatively, 14 patients suffered from traumatic cerebral infarction of different grades. After follow-ups of 24 months, 8 patients had relatively good prognosis, with 4 patients having good recoveries and 4 having middle disability; the other 8 had bad prognosis, including 3 patients being seriously disable and 5 kept vegetative state. CONCLUSIONS: Impact injury and counterblow are the main reasons to the injury of Labbé vein, which consequently leads to serious traumatic cerebral infarction and bad prognosis. Intraoperatively, it is quite important to protect Labbé vein during the surgery, which should not be easily cut or obstructed by electric coagulation, and this is an effective way to improve the prognosis of these patients.