The Experts below are selected from a list of 164547 Experts worldwide ranked by ideXlab platform
Shasha Cheng - One of the best experts on this subject based on the ideXlab platform.
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on Line Measurement of propofol using membrane inlet ion mobility spectrometer
Talanta, 2012Co-Authors: Qinghua Zhou, Weiguo Wang, Huaiwen Cang, Yongzhai Du, Chuang Chen, Shasha ChengAbstract:Abstract The concentration of propofol in patient's exhaled air is an indicator of the anesthetic depth. In the present study, a membrane inlet ion mobility spectrometer (MI-IMS) was built for the on-Line Measurement of propofol. Compared with the direct sample introduction, the membrane inlet could eliminate the interference of moisture and improve the selectivity of propofol. Effects of membrane temperature and carrier gas flow rate on the sensitivity and response time have been investigated experimentally and theoretically. Under the optimized experimental conditions of membrane temperature 100 °C and carrier gas flow rate 200 mL min−1, the calculated limit of detection (LOD) for propofol was 1 ppbv, and the calibration curve was Linear in the range of 10–83 ppbv with a correlation coefficient (R2) of 0.993. Finally, the propofol concentration in an anaesthetized mouse exhaled air was monitored continuously to demonstrate the capability of MI-IMS in the on-Line Measurement of propofol in real samples.
Gui Yun Tian - One of the best experts on this subject based on the ideXlab platform.
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On-Line Measurement of surface roughness by laser light scattering
Measurement Science and Technology, 2006Co-Authors: Rong-sheng Lu, Gui Yun TianAbstract:On-Line roughness Measurement of a surface with one-dimensional manufacturing marks is difficult to implement. For example, a contact stylus-type inspection method often does not perform very well or fails without any prior knowledge of the mark distribution on the surface. In this paper, we propose an on-Line surface roughness Measurement method based on laser light scattering, which is very effective for roughness Measurement of one-dimensional manufacturing surfaces. The surface roughness is obtained from the spatial distribution of the scattered light intensity. The Measurement setup has a very simple configuration, which consists of a CCD sensor, a collimated diode laser and an expander. The orientation of the spatial distribution of the scattered light intensity from the surface, which depends on the surface orientation, is detected by the CCD sensor, and then the mark direction can be readily determined from image processing. After that the root-mean-square (RMS) height of the surface roughness is extracted by means of image processing of the scattered light distribution in the direction parallel to the manufacturing mark, rather than in the direction perpendicular to the mark which is often followed by other Measurement probes. The experimental tests show that the non-contact method has great potential for on-Line surface roughness Measurement.
Qinghua Zhou - One of the best experts on this subject based on the ideXlab platform.
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trap and release membrane inlet ion mobility spectrometry for on Line Measurement of trace propofol in exhaled air
Analytical Methods, 2014Co-Authors: Qinghua Zhou, Weiguo Wang, Enyou Li, Xin Wang, Yulei Gong, Tuanshuai Qu, Jinghua Li, Changsong Wang, Haiyang LiAbstract:Monitoring the exhaled propofol concentration is helpful for anaesthetists to ensure the safety of patients and to adjust the anaesthesia depth. In this study, a trap-and-release membrane inlet ion mobility spectrometer (TRMI-IMS) was constructed for on-Line Measurement of trace propofol in exhaled air. The effects of trap-and-release parameters such as the trap temperature, release temperature and carrier gas flow rate were investigated. Once optimum experimental parameters were identified, the limits of detection (LODs) for propofol at sampling times of 0.5, 1, 2, and 3 min were found to be 17, 8, 3, and 2 pptv, respectively. With a sampling time of 1 min, the response of TRMI-IMS to propofol was enhanced by a factor of 9 as compared with that of constant temperature MI-IMS; the calibration curve resulting from three individual experiments was Linear in the range of 0.1 to 2.5 ppbv. Finally, TRMI-IMS was performed on eleven patients undergoing thyroidectomy surgery to on-Line monitor the exhaled propofol. The correlation coefficients (R2) between TRMI-IMS signal intensities and calculated propofol plasma concentrations set in the TCI system were estimated to be in a range of 0.69 to 0.93, demonstrating the potential of TRMI-IMS for on-Line predicting the propofol concentration in plasma by exhaled air analysis.
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on Line Measurement of propofol using membrane inlet ion mobility spectrometer
Talanta, 2012Co-Authors: Qinghua Zhou, Weiguo Wang, Huaiwen Cang, Yongzhai Du, Chuang Chen, Shasha ChengAbstract:Abstract The concentration of propofol in patient's exhaled air is an indicator of the anesthetic depth. In the present study, a membrane inlet ion mobility spectrometer (MI-IMS) was built for the on-Line Measurement of propofol. Compared with the direct sample introduction, the membrane inlet could eliminate the interference of moisture and improve the selectivity of propofol. Effects of membrane temperature and carrier gas flow rate on the sensitivity and response time have been investigated experimentally and theoretically. Under the optimized experimental conditions of membrane temperature 100 °C and carrier gas flow rate 200 mL min−1, the calculated limit of detection (LOD) for propofol was 1 ppbv, and the calibration curve was Linear in the range of 10–83 ppbv with a correlation coefficient (R2) of 0.993. Finally, the propofol concentration in an anaesthetized mouse exhaled air was monitored continuously to demonstrate the capability of MI-IMS in the on-Line Measurement of propofol in real samples.
Jeremie De Baerdemaeker - One of the best experts on this subject based on the ideXlab platform.
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on Line Measurement of some selected soil properties using a vis nir sensor
Soil & Tillage Research, 2007Co-Authors: Abdul Mounem Mouazen, Jeremie De Baerdemaeker, Mohammadreza Maleki, Herman RamonAbstract:Abstract The on-Line Measurement of soil properties is essential for site-specific application of different inputs into agricultural soils. Using a previously developed soil sensor for on-Line Measurement of soil properties, primary results about carbon (C), moisture content (MC), pH and phosphorous (P) were reported. The on-Line sensor consisted of a soil penetration unit (subsoiler), to which the optical probe to acquire soil spectra from the bottom of the trench opened by the subsoiler chisel is attached. A mobile, fibre-type, visible (VIS) and near infrared (NIR) spectrophotometer (Zeiss Corona 45 visnir fibre, Germany), with a Measurement range of 306.5–1710.9 nm was used to measure soil spectra in reflectance mode. General calibration models were established under non-mobile laboratory conditions, on the basis of two sample sets collected from large geographical areas covering Belgium and northern France. These models were developed using partial least squares (PLS) regression coupled with the full cross-validation technique. On the basis of the values of coefficient of multiple determination ( R 2 ) and the ratio of standard deviation of calibration set (S.D.) to root mean square error of cross-validation (RMSECV), the prediction of MC was evaluated as good, whereas the predictions of C, pH and P were evaluated as only possible to provide quantitative approximations. When these models were validated using on-Line measured spectra, they provided moderately similar maps to those measured with the reference methods. The best similarity was obtained for MC maps. Mean error values of 5.97, 0.37, 27.48 and 5.10% were found between the on-Line and reference Measurements of total carbon (C-tot), MC, pH and available phosphorous (P-avl), respectively, suggesting the potential use of the VIS–NIR sensing system for on-Line Measurement of soil properties.
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on Line Measurement of grain quality with nir technology
Transactions of the ASABE, 2004Co-Authors: K Maertens, P Reyns, Jeremie De BaerdemaekerAbstract:A feasibility study was conducted to measure grain quality (moisture and protein content) with near-infrared reflection (NIR) technology on a conventional New Holland TX64 combine harvester. A Zeiss Corona NIR sensor was installed on a bypass unit of the clean grain elevator, and reference samples were taken at the end of the bubble-up auger, which transports the grain from the clean grain elevator to the grain bin. Measured signals at the diode array of the spectrophotometer were highly variable in time, and an appropriate low-pass filter was designed to extract relevant spectra at a sampling rate of 1 Hz. In addition, an optimal time shift was calculated between the location of the NIR Measurement and the reference sampling to guarantee an optimal synchronization between the measured spectra and reference values. Preprocessing, calibration, and validation were executed using the PLSplus/IQ module of the GRAMS/32 software package. The calibration models were developed using the PLS algorithm and validated through cross-validation. Cross-validation errors of 0.57% and 0.31% were achieved for the on-Line protein and moisture content Measurements, respectively. These accuracies are comparable with the prediction accuracy that was achieved on a similar, but stationary, unit and prove the technical feasibility of estimating grain quality on-the-go with NIR technology.
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on Line Measurement of grain quality with nir technology
International Conference on Crop Harvesting and Processing, 2003Co-Authors: K Maertens, P Reyns, Jeremie De BaerdemaekerAbstract:During the summer season of 2000, a feasibility study is carried out to measure grain quality (moisture and protein content) with Near Infrared Reflection (NIR) technology on a conventional TX64 New Holland combine harvester. A Zeiss Corona 45 NIR 1.7 sensor was installed on a bypass of the clean grain elevator. Parallel with the NIR Measurement, grain samples were taken at the end of the bubble-up auger that transports the grain from the clean grain elevator to the grain bin. Measured signals at the diode array of the spectrophotometer are highly variable in time and since data is acquired at a sampling rate of 23 Hz, an appropriate low pass filter is designed to obtain every second a relevant spectrum. In addition, an optimal time shift is calculated between the location of the NIR Measurement and the sampling spot, in order to make the comparison between the estimated spectra and grain samples as accurate as possible. The spectra are first spectrally converted to either absorbance or Kubelka-Munk values. The required spectra of a white and black standard are time-interpolated between the standard Measurements executed closest before and after the selected on-Line spectrum. Preprocessing, calibration and validation are executed using the PLSplus/IQ module included in the GRAMS/32 software package. After application of Mean Centering, the Multiple Scatter Correction, Standard Normal Variate and detrending algorithm are applied. The calibration models are developed using the PLS algorithm and validated through cross-validation.
Heikki Paakkanen - One of the best experts on this subject based on the ideXlab platform.
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membrane inlet ion mobility spectrometry for on Line Measurement of ethanol in beer and in yeast fermentation
Analytica Chimica Acta, 1995Co-Authors: Tapio Kotiaho, Frants Roager Lauritsen, Hans Degn, Heikki PaakkanenAbstract:Abstract A membrane inlet ion mobility spectrometric method was developed for on-Line Measurement of ethanol concentration in beer and in yeast fermentation. Main parts of the Measurement system are an ion mobility spectrometer, M90, and a custom built membrane inlet. The M90 ion mobility spectrometer is unique in the sense that positive and negative ions are simultaneously measured at 6 different detection channels, 3 for positive ions and 3 for negative ions. The custom built membrane inlet utilized a microporous polypropylene membrane for sample introduction into the M90 instrument. The developed Measurement system allowed analysis of ethanol at 0.05% ( v v ) levels, clearly sufficient for the applications reported here. Good signal Linearity was observed at positive ion channels 1 and 3 in ethanol concentration range 0.2−10% ( v v ), calculated correlation coefficients were 0.989 and 0.999, respectively. Agreement between the ethanol concentration measured by membrane inlet ion mobility spectrometry and the values declared on the beer bottle labels was good. Reproducibility of signals of the detection channels which gave the best response for ethanol was excellent in ethanol concentration Measurement of beer samples, coefficient of variation was 1% for all these channels. Membrane inlet ion mobility spectrometry was also shown to be capable of on-Line ethanol Measurement, confirmed by membrane inlet mass spectrometry, during yeast fermentations.