Wyniki wyszukiwania - BazTech

1

2-Methyl-2,4-pentanediol gas sensor properties of nano-SnO2 flat-type coplanar gas sensing arrays at low detection limit

Zhu C., Huang K., Yuan F, Xie C

Materials Science Poland

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2014

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Vol. 32, No. 2

181--187

EN

Nano-SnO2 flat-type coplanar 2-Methyl-2,4-pentanediol (MPD) gas sensor arrays were fabricated by a screen-printing technique based on nano-SnO2 powders prepared by a hydrothermal method. The results show that the fabricated gas sensor arrays have good MPD gas sensing characteristics, such as good selectivity and response-recovery characteristics. Especially, they can be used for detecting the concentration of MPD gas as low as 1 ppm which is much lower than the legal concentration of 20 ppm or 25 ppm. The good sensing properties indicate that the SnO2 gas sensor arrays have great potential for on-line or portable monitoring of MPD gas in practical environments.

2

Development of a method for comprehensive and quantitative analysis of Yohimbine in Pausinystalia yohimbe by liquid chromatography-ion trap mass spectrometry

Chen Q., Li P., Li B., Yuan F., Li X., Zhu J.

Acta Chromatographica

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2011

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Vol. 23, no. 4

629--639

EN

A rapid and sensitive method for the identification and quantification of yohimbine in Pausinystalia yohimbe is described. The method used is liquid chromatography-quadrupole ion trap mass spectrometry (LC-QIT/MS). The yohimbine standard solution was directly infused into the ion trap mass spectrometers (IT/MS) for collecting the MSn spectra. The major fragment ions of yohimbine were confirmed by MSn at m/z 355, 224, 212, and 144, in the positive-ion mode. The possible main fragment ion cleavage pathway was studied. Yohimbine provided good signals corresponding to the protonated molecular ion [M + H]+. The method is reliable and reproducible, and the detection limit is 0.1 ng mL-1. The method was validated in the concentration range 0.1–50 μg mL-1; the intra- and interday precision ranged from 1.36% to 2.73%; and the accuracy was 96.5–108.2%. The mean recovery of yohimbine was 97.1–101% with a relative standard deviation (RSD) <1.93%. The LC-IT/MS method was successfully applied to determine the yohimbine in P. yohimbe.

3

Real time multiple planar volume clipping based on the programmable graphics process unit

Yuan F.

Optica Applicata

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2009

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Vol. 39, nr 2

331-345

EN

We propose a real time volume clipping method which is capable of using several analytical planes for virtual clipping, in order to display internal anatomical structures within volumetric data sets. A single proxy plane is used for computation of the direction of a ray that is cast from the viewpoint. Intersections between the rays and the planes are computed on graphics process unit (GPU). The start and end points for each ray are determined by analyzing relationships with the ray direction, intersections and the normal of planes. Then the volume integral is computed along the ray from the start point to the end point. To obtain immediate visual feedback of clipping effects, we implement translation and rotation of planes on GPU to interactively change the shape of clip object. At last, several experiments were performed on a standard PC with a GeForce FX8600 graphics card. Experimental results show that the method can freely clip and clearly visualize volumetric data sets at real time frame rates.

4

An iterative programmable graphics process unit based on ray casting approach for virtual endoscopy system

Yuan F.

Optica Applicata

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2008

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Vol. 38, nr 3

519-530

EN

In this paper, a fast graphics process unit (GPU) based ray casting algorithm is presented to improve image quality. A linear interpolation is used to estimate the intersection between a ray and isosurfaces. Thus, resampling artefacts is greatly reduced and the performance is not influenced. An iterative estimation is presented to further improve image quality. According to the distance the ray goes across, z values in the z-buffer are modified to implement hiding of hybrid scenes. Experimental results show that the algorithm can produce high quality images at interactive frame rates and implement hiding of hybrid scenes very well.