Biomedical subjects

Gang Yu

Publications and source records attributed to Gang Yu.

61 records · Page 4Linked to original sources

PubMed2002

[Structural properties of TiO2 thin film modified by carbon black].

TiO2 photocatalytic film(CB-TiO2) modified by doping carbon black was prepared, and the some structural properties, such as specific surface area, phase, crystal grain size and excitation wavelength were gave, through liquid nitrogen adsorption, X-ray diffraction(XRD) and diffuse reflection spectrum(DRS). The results indicated that adsorbability of CB-TiO2 was greatly improved, BET specific surface area of which enhanced 50%-80% than that of TiO2, baked under 300 degrees C-500 degrees C. And CB modification reduced the crystal grain size, so the temperature of phase transformation was decreased. Corresponding, the photocatalytic activity of CB-TiO2 also was greatly improved, the reaction rate of which was 1.5 times of that of TiO2.

Carbon↗

PubMed2002

[Effects of polyacrylamide on settling and separation of oil droplets in polymer flooding produced water].

The research found anion polyacrylamide (HPAM) had positive and negative effects on oil-water separation. Polymer made oily wastewater's viscosity increase and reduce rising velocity, and polymer can also increase intensity of water films between oil droplets and lengthen coalescence time of oil droplets. Those were not in favor of settling and separation for oil droplets. The positive effects on separation were that polyacrylamide had flocculating activity and made small droplets contact each other and combine into big droplets. When polymer's molecular weight was 2.72 x 10(6), and concentration was less than 800 mg/L, polymer was in favor of oil droplets settling and separation. The prime reason for oily wastewater of polymer flooding difficult to dispose was that initial median diameters of oil droplets were small. The transverse flow oil separator can intensify oil droplets combination and shorten rising time. The locale experiments showed the separator was suitable for dealing with oily wastewater of polymer flooding.

Acrylic Resins↗

PubMed2002

[Kinetic study on photodegradation of acid red 3B catalyzed by heteropoly acid].

The kinetics of degradation of Acid Red 3B photocatalyzed by PW12O(40)3- was studied in aqueous solution. Light intensity, dissolved oxygen, added amount of the catalyst, and the initial concentration of substrate had positive effects on the photodegradation rate of Acid Red 3B. The results were explained by Langmuir-Hinshelwood model, implying there was precomplexation between catalyst and substrate. Results compared to UV/TiO2 method indicated that heteropoly acid is an efficient photocatalyst.

Catalysis↗

PubMed2002

[Degradation of toluene in the gas phase by combined ozone and photocatalysis].

The degradation of toluene (10-80 mg/m3) in the gas phase by combined ozone and photocatalysis was studied. The effect of the inlet concentration, air flow rate and humidity on the degradation efficiency and removal load was investigated. Then the efficiency of combined ozone and photocatalysis was compared with that of photocatalysis. The experiment results indicated that combination of ozone and photocatalysis was far more efficient than photocatalysis in degrading toluene, especially under high-level inlet concentration. When the inlet concentration was in the range of 10-40 mg/m3, the degradation efficiency of combined ozone and photocatalysis was over 90% and dropped linearly and very slowly with the increase of inlet concentration of toluene. The degradation efficiency of combined ozone and photocatalysis was slightly affected by humidity with the efficiency difference less than 2.5%.

Catalysis↗

PubMed2002

[Influence of doping the nanosized SiO2 powder on structure and activity of photocatalytic films].

Regard to the poor adsorbability of the fixing film photocatalyst, a new TiO2 thin film by doping the nanosized SiO2 power with large specific surface area into sol for coating film was prepared. According to the results of characterization by XRD, SEM, FTIR techniques, it was found that the films were mainly anatase structure, containing a little rutile and its mean crystallite size was about 27 nm. And doped SiO2 was dispersed into films forming the amorphous cluster with the size form more than ten nanometers to scores of nanometers. The doping of SiO2 had no effect on the crystal structure and the surficial group of TiO2, except for increasing specific surface area. The result of photocatalytic degradation showed that activity of the film doped by SiO2 largely increased and was greatly influenced by the size and amount of doped SiO2. Besides, this photocatalyst also had very good stability. During the course of continuous experiment for more than 30 days, removal efficiency of reactive brilliant red X-3B was kept at about 80% all the time.

Catalysis↗

PubMed2002

[The degradation of dye X-3B in photocatalysis enhanced by the electric field].

Using 365 nm and 254 nm UV lamp as light source, the degradation of dye X-3B in photolysis, photocatalysis and electrical enhanced photocatalysis was studied in this research. The result shows that the degradation rate of photocatalysis of X-3B was faster than one of photolysis of X-3B. The degradation rate of electrical enhanced photocatalysis was faster than the photocatalysis while the direction of the electric field was opposite with the direction of UV radiation and its degradation rate was slower while the direction of the electric field was of the same direction as UV radiation.

Boron Compounds↗

PubMed2002

[Research of image spectrometer using linear variable interference filter].

In the present work we have designed a small-size portable imaging spectrometer using linear variable interference filter, with CCD camera as picture sensor, and micromotion stage to bring along interference filter which scan across every pixel of CCD array. The difference column pixel in the picture which we get at every step is monocolour partial image under different wavelength, with the step by step, these column monocolour pixels change the wavelength. And finally we reassembled these images and get the whole monocolour image with different wavelength. The interval of sweep step length decided by the required spectrum resolution and the required wavelength interval of different pictures. The experiment demonstrated the resolution of this spectrometer is about 16 nm, but that major reason of the limiting resolution is the band width of the linear variable interference filter. The spatial resolution of the instrument ultimately decided by CCD, filter and imaging lens. This spectrometer has some characters such as compact structure, higher spatial resolution, higher spectrum resolution, higher scan rate and so on. Furthermore, an application of this instrument in distinguishing from camouflage have been showed.

Analog-Digital Conversion↗