yanjun gong - Academia.edu (original) (raw)

Papers by yanjun gong

Cheminform, 2004

For Abstract see ChemInform Abstract in Full Text.

Chemistry of Materials, 2005

Fluorescent microspheres were constructed by incorporating CdTe nanocrastals (NCs), costabilized ... more Fluorescent microspheres were constructed by incorporating CdTe nanocrastals (NCs), costabilized by both thioglycerol and thioglycolic acid, into poly(N-isopropylacrylamide) (PNIPAM) microspheres through hydrogen bonding between the ligands capped on CdTe NCs and the PNIPAM chains. The loading capacity of PNIPAM was found to be dependent on the incubation temperature. Under optimized conditions the average spatial distance between CdTe NCs loaded into hydrogel spheres is still greater than that required for Förster energy transfer between CdTe NCs; therefore, very little change in the photoluminescence of CdTe NCs was observed after they were loaded into PNIPAM micropheres. Multiplex optical encoding was realized by loading differently sized NCs into single gel spheres. The emission color of the resultant fluorescent spheres was mainly determined by the ratio of differently sized NCs incorporated. Although CdTe NCs in the hydrogel increased the cross-linking degree of the PNIPAM network, the volume of the resultant composite spheres remained tunable against temperature. Therefore, Förster energy transfer between differently sized NCs loaded can be initiated by increasing the environmental temperature, creating a temperature-responsive emission.

Chemistry of Materials, 2004

A strong photoluminescence enhancement effect of illumination on CdTe nanocrystals stabilized by ... more A strong photoluminescence enhancement effect of illumination on CdTe nanocrystals stabilized by thioglycolic acid (TGA) was observed. Under optimized conditions, the fluorescence quantum yield of CdTe nanocrystals in aqueous solution reached 85% at room temperature. Optical measurements indicated that the photodegradation of TGA rather than NCs was the main reason for the PL enhancement effect since sulfide ions released from TGA during illumination coordinated with cadmium ions on the surface of CdTe and formed a shell structure of CdS there. X-ray photoelectron spectroscopic results further proved the formation of CdS shell on the CdTe core during illumination. The colloidal solution of CdTe/ CdS core-shell nanocrystals with photoluminescence quantum yield higher than 80% turned out to be very stable. Therefore, the current investigations not only reveal the PL enhancement effect of illumination, but also provide a useful synthetic route for producing water-soluble and highly fluorescent CdTe/CdS core-shell nanocrystals.

Journal of Colloid and Interface Science, 2011

A seeded approach was developed to synthesize high-silica EU-1 zeolite via inhibiting the co-crys... more A seeded approach was developed to synthesize high-silica EU-1 zeolite via inhibiting the co-crystallization of ZSM-48 in the presence of hexamethonium (HM) ions. A systematic study was carried out to determine factors such as seed content and SiO(2)/Al(2)O(3) ratio, which influenced the crystallization of high-silica EU-1 and transformation of EU-1 into ZSM-48. Using EU-1 seeds, not only well-crystallized pure EU-1 zeolites with SiO(2)/Al(2)O(3) ratios more than 500 were synthesized, but also the co-crystalline of ZSM-48/EU-1 or pure ZSM-48 was obtained in control from silica-rich mixture gels. Furthermore, the kinetic features of the seeded synthesis of EU-1 zeolites with SiO(2)/Al(2)O(3) ratios of 55, 190, and 500 were examined. It was found that seeds played crucial roles in the decrease of apparent activation energy of EU-1 nucleation and inhibiting the transformation of EU-1 into ZSM-48. The HM and Al species performed synergistic roles to inhibit the formation ZSM-48 during high-silica EU-1 nucleation and crystal growth.

Fuel Processing Technology, 2009

Solid adsorbents Cu(I) and Ag(I) metal exchanged beta zeolites were prepared by solid-state ion-e... more Solid adsorbents Cu(I) and Ag(I) metal exchanged beta zeolites were prepared by solid-state ion-exchange (SSIE) method. Crystallographic structure of the prepared adsorbents has been characterized by XRD analysis. The texture of the prepared adsorbents was investigated using N 2 sorption. Pyridine IR measurements have been carried out to investigate the nature of the acid sites of the adsorbents. The deep-desulfurization performance of such adsorbents has been evaluated through fixed-bed adsorption technique with model gasoline containing thiophene and benzothiophene at ambient temperature and pressure.

Energy & Fuels, 2010

A novel micro-and mesoporous composite molecular sieve (denoted as LMC) was synthesized by using ... more A novel micro-and mesoporous composite molecular sieve (denoted as LMC) was synthesized by using the nanocrystal clusters of zeolite L as the precursor and a cation surfactant cetyltrimethylammonium bromide (CTAB) as the template. The physicochemical properties of samples were characterized by means of X-ray diffraction (XRD), nitrogen-adsorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), 27 Al and 29 Si magic angle spinning nuclear magnetic resonance (MAS NMR), Fourier transform infrared spectroscopy (FTIR), and Fourier transform infrared spectroscopy of pyridine adsorption (Py-FTIR). The results showed that composite molecular sieve LMC was synthesized by the self-assembly of zeolite L nanocrystal clusters under the template effect of CTAB. In addition, surface area, pore volume, and pore size of LMC significantly increased in comparison to those of conventional microporous zeolite L. The results measured by Py-FTIR showed that LMC had an appropriate acid amount and acid distribution. For evaluation of fluid catalytic cracking (FCC) gasoline hydrodesulfurization (HDS), the catalyst that introduced material LMC exhibited the excellent performances of desulfurization, isomerization, aromatization, olefin retention, and preserving the research octane number (RON) value compared to the catalyst that introduced ordinary microporous zeolite L or mesoporous Al-MCM-41 and used bare alumina as the support. The excellent catalytic performances of the catalyst should be attributed to the appropriate acidity distribution and open pore structure of material LMC.

Catalysis Letters, 2001

Mesoporous silicas were functionalized with phenyl groups and were used as solid acid catalysts i... more Mesoporous silicas were functionalized with phenyl groups and were used as solid acid catalysts in acetalization of aldehydes and ketones with ethylene glycol or methanol. It was shown that cyclohexanone as well as aromatic and linear aldehydes could be converted to the corresponding dimethylacetals in high conversion and selectivity over the catalyst. They also performed well in the isopropylation reactions of naphthalene with isopropanol.

Microporous and Mesoporous Materials, 2004

Organic-inorganic hybrid mesoporous silicas of MSU with different sizes of organic functionalitie... more Organic-inorganic hybrid mesoporous silicas of MSU with different sizes of organic functionalities of methyl, vinyl, or 3-mercaptopropyl were prepared by using inexpensive sodium silicate and organotrialkoxysilane as the silica precursor via fluoride-mediated co-condensation. The results indicated that both sodium silicate and organotrialkoxysilane could be translated quantitatively into organic-inorganic hybrid materials with high BET surface area (899-1042 m 2 /g) and pore volume (0.70-1.09 cm 3 /g). The key to the synthesis of such materials from sodium silicate-organotrialkoxysilane was the separation of hydrolysis and condensation of silica precursor to avoid phase separation due to the obvious difference of condensation rate between aqueous silicate (solution of sodium silicate) and organotrialkoxysilane. Compared with the materials prepared from tetraethoxysilane (TEOS)-organotrialkoxysilane under the same synthetic conditions, the derivatives from sodium silicate-organotrialkoxysilane owned more ordered framework structure and narrower pore diameter distribution due to faster condensation of aqueous silicate.

Journal of Materials Science Letters, 2003

A variety of ordered mesoporous materials have been synthesized by a template method using supram... more A variety of ordered mesoporous materials have been synthesized by a template method using supramolecular assembly of the surfactant molecules, however, many applications (such as adsorption, ion exchange, catalysis and sensing) require materials of specific surface function. In order to introduce functionality into these mesoporous materials, organic modification techniques are enjoying a renewed interest. Recently, much work focused on one-step synthesis of mesoporous structure containing covalently linked organic functionalities [8][9][10]. The primary approach was that expensive trialkoxysilane, such as tetrethoxysilane, and organotrialkoxysilane precursors were mixed at the first step, then the obtained mixture co-condensed in the presence of a surfactant. In some instances the organotrialkoxysilanes with small organic groups can enter framework walls of the mesostructures in the co-condensation [10], the presence of only three hydrolyzable Si OR bonds in intraframework is likely to impede the complete cross-linking of the silica network, resulting in the perturbation in the framework ordering. Here we report the preparation of MSU-type mesoporous organosilica from inexpensive sodium silicate (Na 2 SiO 3 · 9H 2 O) and organotrialkoxysilane. This method, which we called "step by step," greatly reduced the possibility that organotrialkoxysilanes enter framework walls of the mesostructures. Furthermore, to the best of our knowledge, this was the first preparation of mesoporous organosilica from sodium silicate and organotrialkoxysilanes, it perhaps opens up the field of large-scale preparation for these materials.

Signal Processing-image Communication, 2010

ABSTRACT

International Journal of Infrared and Millimeter Waves, 2005

Infrared ray (IR) has great potential in medical diagnosis and therapy. In order to detect tumor ... more Infrared ray (IR) has great potential in medical diagnosis and therapy. In order to detect tumor in skin, we set up the steady-state and time domain IR diffusion model of an n-layered matched medium with an infinitely thick. We utilize the diffuse equation to solve a five-layered infinite matched medium and obtain the accurate solution of a matched medium of the steady state and time domain in tissue. We compare the steady-state spatially resolved reflectance calculated with Monte-Carlo simulations. The Monte-Carlo simulation shows that the solution is valid. Our equation can be used to obtain the tumor information in medical diagnosis and therapy.

We analyze the inherent channels of hyperspectral data with convex geometry analysis method. In t... more We analyze the inherent channels of hyperspectral data with convex geometry analysis method. In this paper, a method-Volume Method, which selects the inherent channels of hyperspectral data, is presented. The concept of convexity geometry can be used to great advantage in the analysis of hyperspectral data. Convex simplex and inherent dimensionality concept is discussed on base of convex geometry. A set of 252-band hyperspectral data is applied to testify the Volume Method. The endmember proportions are calculated in the inherent dimensional space whose channels are selected by the Volume Method, compared with Constrained Least Squares Method in 252-space.

The appearance of imaging spectrometer enables us to acquire hyperspectral remote sensing images,... more The appearance of imaging spectrometer enables us to acquire hyperspectral remote sensing images, so we can acquire abundant spectral information about earth material, and we can analyse mixed pixels questions. In this paper, a hyperspectral image about a region given is analysed. We unmix the earth material interested from the hyperspectral image about the region by using Convex Geometry Analysis(CGA) method. The CLS proportion images and inherent proportion images about earth material interested of the hyperspectral image are obtained.

Color Research and Application, 2005

If we study color reproduction, such as computer color matching or the appraisal of metametric in... more If we study color reproduction, such as computer color matching or the appraisal of metametric index, we wish to understand the characteristic of color differences that are caused by the object spectral reflectivity change at each wavelength. If we simulate the light source, we wish to know the characteristics of color differences that are caused by change in relative power distribution of the light source at each wavelength; if we simulate a human eye instrument, we wish to know the characteristics of color differences that are caused by change in visual sense of human eyes at each wavelength. So, we define the color-sensitivity functions of an object, a light source, and human eyes. According to the chromatic theory, the color-sensitive functions of an object, a light source, and human eyes are defined in the widely used CIE1976 (L*a*b*) color space and color difference.1 Their mathematical formulae are deduced. The three kinds of color-sensitive functions are studied systematically and comprehensively in the whole color space. The characteristics of the color-sensitive functions are summarized, and the mathematical models of the three kinds of color-sensitive functions can be utilized in some fields such as computer color matching, simulation of a standard light source, and humans viewing a colorimeter. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 118–124, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20089

On the basis of spectrophotometric color matching, the color difference weight factor is proposed... more On the basis of spectrophotometric color matching, the color difference weight factor is proposed and used in the thesis. The weight factor can be expressed as ωj = {{[(x(λj)]2 + [y(λj)]2 + [z(λj)]2}[S(λj)]2}» and obtained according to the assumption of Σj(ΔXj)2+(ΔYj)2+(ΔZj)2 -> min, i. e., in the range of visible spectrum it is assumed that the square sum of tri-stimulus value deviation produced by spectrum deviation at each wavelength is minimal.Through comparison with spectrophotometric color matching, we find a new weight factor. The new factor multiplied by the variety of reflectivity is the color difference, which is cause by the difference of reflectivity between standard color and matching color. So we name the weight factor: color difference weight factor. The prediction of computer shows the color difference produced by the weight factor is smaller than that produced by the two weight factors which were designed by Schmid and Strockash.

International Journal of Infrared and Millimeter Waves, 2004

Near-IR radiation is often utilized to detect the properties in tissues, up to now, a semi-infini... more Near-IR radiation is often utilized to detect the properties in tissues, up to now, a semi-infinite medium photon migration model and a two-layered turbid medium model are applied widely. But the solution is approximate. In this paper, According to the diffusion equation, employing the extrapolated boundary condition, we analyze the diffusion of photons of a three-layered matched medium, set up the accurate solution of the diffuse equation. In order to validate our solution, we apply the Monte-Carlo simulation of the time domain and the steady-state, we find that the solution of a three-layered matched medium diffusion equation not only accord with the Monte-Carlo simulation. The solution can still solve the problems of a two-layered turbid medium model and a semi-infinite medium photon migration model

International Journal of Infrared and Millimeter Waves, 2005

Near-IR radiation is often utilized to detect the properties in tissues, up to now, a semi-infini... more Near-IR radiation is often utilized to detect the properties in tissues, up to now, a semi-infinite medium photon migration model and a two-layered turbid medium model are applied widely. In this paper, we set up the steady-state photon diffusion model of three-layered mismatched medium. We utilize the diffuse equation to solve a three-layered mismatched medium and obtain the accurate solution of a three-layered mismatched medium of the steady state in tissue. We find that the solution of a three-layered mismatched medium diffusion equation not only accord with the Monte-Carlo simulation, but can still solve the problems of a two-layered turbid medium model.

Hyperspectral image can be analyzed by Convex Geometry Analysis(CGA) method. CGA method can unmix... more Hyperspectral image can be analyzed by Convex Geometry Analysis(CGA) method. CGA method can unmix endmembers from hyperspectral image. The endmember proportions of mixed pixels can be calculated in inherent dimensional space, and a proportion image, which is called inherent proportion image, is obtained. The endmember proportions of mixed pixels can be calculated in n-space by the Constrained Least Squares, and a proportion image, which is called CLS proportion image, is obtained. In this paper, the inherent proportion image and CLS proportion image of a 30-band remote sensing image are obtained. The two proportion images are similar. The targets that are smaller than earth surface pixel can be identified by the inherent proportion image.

Cheminform, 2004

For Abstract see ChemInform Abstract in Full Text.

Chemistry of Materials, 2005

Fluorescent microspheres were constructed by incorporating CdTe nanocrastals (NCs), costabilized ... more Fluorescent microspheres were constructed by incorporating CdTe nanocrastals (NCs), costabilized by both thioglycerol and thioglycolic acid, into poly(N-isopropylacrylamide) (PNIPAM) microspheres through hydrogen bonding between the ligands capped on CdTe NCs and the PNIPAM chains. The loading capacity of PNIPAM was found to be dependent on the incubation temperature. Under optimized conditions the average spatial distance between CdTe NCs loaded into hydrogel spheres is still greater than that required for Förster energy transfer between CdTe NCs; therefore, very little change in the photoluminescence of CdTe NCs was observed after they were loaded into PNIPAM micropheres. Multiplex optical encoding was realized by loading differently sized NCs into single gel spheres. The emission color of the resultant fluorescent spheres was mainly determined by the ratio of differently sized NCs incorporated. Although CdTe NCs in the hydrogel increased the cross-linking degree of the PNIPAM network, the volume of the resultant composite spheres remained tunable against temperature. Therefore, Förster energy transfer between differently sized NCs loaded can be initiated by increasing the environmental temperature, creating a temperature-responsive emission.

Chemistry of Materials, 2004

A strong photoluminescence enhancement effect of illumination on CdTe nanocrystals stabilized by ... more A strong photoluminescence enhancement effect of illumination on CdTe nanocrystals stabilized by thioglycolic acid (TGA) was observed. Under optimized conditions, the fluorescence quantum yield of CdTe nanocrystals in aqueous solution reached 85% at room temperature. Optical measurements indicated that the photodegradation of TGA rather than NCs was the main reason for the PL enhancement effect since sulfide ions released from TGA during illumination coordinated with cadmium ions on the surface of CdTe and formed a shell structure of CdS there. X-ray photoelectron spectroscopic results further proved the formation of CdS shell on the CdTe core during illumination. The colloidal solution of CdTe/ CdS core-shell nanocrystals with photoluminescence quantum yield higher than 80% turned out to be very stable. Therefore, the current investigations not only reveal the PL enhancement effect of illumination, but also provide a useful synthetic route for producing water-soluble and highly fluorescent CdTe/CdS core-shell nanocrystals.

Journal of Colloid and Interface Science, 2011

A seeded approach was developed to synthesize high-silica EU-1 zeolite via inhibiting the co-crys... more A seeded approach was developed to synthesize high-silica EU-1 zeolite via inhibiting the co-crystallization of ZSM-48 in the presence of hexamethonium (HM) ions. A systematic study was carried out to determine factors such as seed content and SiO(2)/Al(2)O(3) ratio, which influenced the crystallization of high-silica EU-1 and transformation of EU-1 into ZSM-48. Using EU-1 seeds, not only well-crystallized pure EU-1 zeolites with SiO(2)/Al(2)O(3) ratios more than 500 were synthesized, but also the co-crystalline of ZSM-48/EU-1 or pure ZSM-48 was obtained in control from silica-rich mixture gels. Furthermore, the kinetic features of the seeded synthesis of EU-1 zeolites with SiO(2)/Al(2)O(3) ratios of 55, 190, and 500 were examined. It was found that seeds played crucial roles in the decrease of apparent activation energy of EU-1 nucleation and inhibiting the transformation of EU-1 into ZSM-48. The HM and Al species performed synergistic roles to inhibit the formation ZSM-48 during high-silica EU-1 nucleation and crystal growth.

Fuel Processing Technology, 2009

Solid adsorbents Cu(I) and Ag(I) metal exchanged beta zeolites were prepared by solid-state ion-e... more Solid adsorbents Cu(I) and Ag(I) metal exchanged beta zeolites were prepared by solid-state ion-exchange (SSIE) method. Crystallographic structure of the prepared adsorbents has been characterized by XRD analysis. The texture of the prepared adsorbents was investigated using N 2 sorption. Pyridine IR measurements have been carried out to investigate the nature of the acid sites of the adsorbents. The deep-desulfurization performance of such adsorbents has been evaluated through fixed-bed adsorption technique with model gasoline containing thiophene and benzothiophene at ambient temperature and pressure.

Energy & Fuels, 2010

A novel micro-and mesoporous composite molecular sieve (denoted as LMC) was synthesized by using ... more A novel micro-and mesoporous composite molecular sieve (denoted as LMC) was synthesized by using the nanocrystal clusters of zeolite L as the precursor and a cation surfactant cetyltrimethylammonium bromide (CTAB) as the template. The physicochemical properties of samples were characterized by means of X-ray diffraction (XRD), nitrogen-adsorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), 27 Al and 29 Si magic angle spinning nuclear magnetic resonance (MAS NMR), Fourier transform infrared spectroscopy (FTIR), and Fourier transform infrared spectroscopy of pyridine adsorption (Py-FTIR). The results showed that composite molecular sieve LMC was synthesized by the self-assembly of zeolite L nanocrystal clusters under the template effect of CTAB. In addition, surface area, pore volume, and pore size of LMC significantly increased in comparison to those of conventional microporous zeolite L. The results measured by Py-FTIR showed that LMC had an appropriate acid amount and acid distribution. For evaluation of fluid catalytic cracking (FCC) gasoline hydrodesulfurization (HDS), the catalyst that introduced material LMC exhibited the excellent performances of desulfurization, isomerization, aromatization, olefin retention, and preserving the research octane number (RON) value compared to the catalyst that introduced ordinary microporous zeolite L or mesoporous Al-MCM-41 and used bare alumina as the support. The excellent catalytic performances of the catalyst should be attributed to the appropriate acidity distribution and open pore structure of material LMC.

Catalysis Letters, 2001

Mesoporous silicas were functionalized with phenyl groups and were used as solid acid catalysts i... more Mesoporous silicas were functionalized with phenyl groups and were used as solid acid catalysts in acetalization of aldehydes and ketones with ethylene glycol or methanol. It was shown that cyclohexanone as well as aromatic and linear aldehydes could be converted to the corresponding dimethylacetals in high conversion and selectivity over the catalyst. They also performed well in the isopropylation reactions of naphthalene with isopropanol.

Microporous and Mesoporous Materials, 2004

Organic-inorganic hybrid mesoporous silicas of MSU with different sizes of organic functionalitie... more Organic-inorganic hybrid mesoporous silicas of MSU with different sizes of organic functionalities of methyl, vinyl, or 3-mercaptopropyl were prepared by using inexpensive sodium silicate and organotrialkoxysilane as the silica precursor via fluoride-mediated co-condensation. The results indicated that both sodium silicate and organotrialkoxysilane could be translated quantitatively into organic-inorganic hybrid materials with high BET surface area (899-1042 m 2 /g) and pore volume (0.70-1.09 cm 3 /g). The key to the synthesis of such materials from sodium silicate-organotrialkoxysilane was the separation of hydrolysis and condensation of silica precursor to avoid phase separation due to the obvious difference of condensation rate between aqueous silicate (solution of sodium silicate) and organotrialkoxysilane. Compared with the materials prepared from tetraethoxysilane (TEOS)-organotrialkoxysilane under the same synthetic conditions, the derivatives from sodium silicate-organotrialkoxysilane owned more ordered framework structure and narrower pore diameter distribution due to faster condensation of aqueous silicate.

Journal of Materials Science Letters, 2003

A variety of ordered mesoporous materials have been synthesized by a template method using supram... more A variety of ordered mesoporous materials have been synthesized by a template method using supramolecular assembly of the surfactant molecules, however, many applications (such as adsorption, ion exchange, catalysis and sensing) require materials of specific surface function. In order to introduce functionality into these mesoporous materials, organic modification techniques are enjoying a renewed interest. Recently, much work focused on one-step synthesis of mesoporous structure containing covalently linked organic functionalities [8][9][10]. The primary approach was that expensive trialkoxysilane, such as tetrethoxysilane, and organotrialkoxysilane precursors were mixed at the first step, then the obtained mixture co-condensed in the presence of a surfactant. In some instances the organotrialkoxysilanes with small organic groups can enter framework walls of the mesostructures in the co-condensation [10], the presence of only three hydrolyzable Si OR bonds in intraframework is likely to impede the complete cross-linking of the silica network, resulting in the perturbation in the framework ordering. Here we report the preparation of MSU-type mesoporous organosilica from inexpensive sodium silicate (Na 2 SiO 3 · 9H 2 O) and organotrialkoxysilane. This method, which we called "step by step," greatly reduced the possibility that organotrialkoxysilanes enter framework walls of the mesostructures. Furthermore, to the best of our knowledge, this was the first preparation of mesoporous organosilica from sodium silicate and organotrialkoxysilanes, it perhaps opens up the field of large-scale preparation for these materials.

Signal Processing-image Communication, 2010

ABSTRACT

International Journal of Infrared and Millimeter Waves, 2005

Infrared ray (IR) has great potential in medical diagnosis and therapy. In order to detect tumor ... more Infrared ray (IR) has great potential in medical diagnosis and therapy. In order to detect tumor in skin, we set up the steady-state and time domain IR diffusion model of an n-layered matched medium with an infinitely thick. We utilize the diffuse equation to solve a five-layered infinite matched medium and obtain the accurate solution of a matched medium of the steady state and time domain in tissue. We compare the steady-state spatially resolved reflectance calculated with Monte-Carlo simulations. The Monte-Carlo simulation shows that the solution is valid. Our equation can be used to obtain the tumor information in medical diagnosis and therapy.

We analyze the inherent channels of hyperspectral data with convex geometry analysis method. In t... more We analyze the inherent channels of hyperspectral data with convex geometry analysis method. In this paper, a method-Volume Method, which selects the inherent channels of hyperspectral data, is presented. The concept of convexity geometry can be used to great advantage in the analysis of hyperspectral data. Convex simplex and inherent dimensionality concept is discussed on base of convex geometry. A set of 252-band hyperspectral data is applied to testify the Volume Method. The endmember proportions are calculated in the inherent dimensional space whose channels are selected by the Volume Method, compared with Constrained Least Squares Method in 252-space.

The appearance of imaging spectrometer enables us to acquire hyperspectral remote sensing images,... more The appearance of imaging spectrometer enables us to acquire hyperspectral remote sensing images, so we can acquire abundant spectral information about earth material, and we can analyse mixed pixels questions. In this paper, a hyperspectral image about a region given is analysed. We unmix the earth material interested from the hyperspectral image about the region by using Convex Geometry Analysis(CGA) method. The CLS proportion images and inherent proportion images about earth material interested of the hyperspectral image are obtained.

Color Research and Application, 2005

If we study color reproduction, such as computer color matching or the appraisal of metametric in... more If we study color reproduction, such as computer color matching or the appraisal of metametric index, we wish to understand the characteristic of color differences that are caused by the object spectral reflectivity change at each wavelength. If we simulate the light source, we wish to know the characteristics of color differences that are caused by change in relative power distribution of the light source at each wavelength; if we simulate a human eye instrument, we wish to know the characteristics of color differences that are caused by change in visual sense of human eyes at each wavelength. So, we define the color-sensitivity functions of an object, a light source, and human eyes. According to the chromatic theory, the color-sensitive functions of an object, a light source, and human eyes are defined in the widely used CIE1976 (L*a*b*) color space and color difference.1 Their mathematical formulae are deduced. The three kinds of color-sensitive functions are studied systematically and comprehensively in the whole color space. The characteristics of the color-sensitive functions are summarized, and the mathematical models of the three kinds of color-sensitive functions can be utilized in some fields such as computer color matching, simulation of a standard light source, and humans viewing a colorimeter. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 118–124, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20089

On the basis of spectrophotometric color matching, the color difference weight factor is proposed... more On the basis of spectrophotometric color matching, the color difference weight factor is proposed and used in the thesis. The weight factor can be expressed as ωj = {{[(x(λj)]2 + [y(λj)]2 + [z(λj)]2}[S(λj)]2}» and obtained according to the assumption of Σj(ΔXj)2+(ΔYj)2+(ΔZj)2 -> min, i. e., in the range of visible spectrum it is assumed that the square sum of tri-stimulus value deviation produced by spectrum deviation at each wavelength is minimal.Through comparison with spectrophotometric color matching, we find a new weight factor. The new factor multiplied by the variety of reflectivity is the color difference, which is cause by the difference of reflectivity between standard color and matching color. So we name the weight factor: color difference weight factor. The prediction of computer shows the color difference produced by the weight factor is smaller than that produced by the two weight factors which were designed by Schmid and Strockash.

International Journal of Infrared and Millimeter Waves, 2004

Near-IR radiation is often utilized to detect the properties in tissues, up to now, a semi-infini... more Near-IR radiation is often utilized to detect the properties in tissues, up to now, a semi-infinite medium photon migration model and a two-layered turbid medium model are applied widely. But the solution is approximate. In this paper, According to the diffusion equation, employing the extrapolated boundary condition, we analyze the diffusion of photons of a three-layered matched medium, set up the accurate solution of the diffuse equation. In order to validate our solution, we apply the Monte-Carlo simulation of the time domain and the steady-state, we find that the solution of a three-layered matched medium diffusion equation not only accord with the Monte-Carlo simulation. The solution can still solve the problems of a two-layered turbid medium model and a semi-infinite medium photon migration model

International Journal of Infrared and Millimeter Waves, 2005

Near-IR radiation is often utilized to detect the properties in tissues, up to now, a semi-infini... more Near-IR radiation is often utilized to detect the properties in tissues, up to now, a semi-infinite medium photon migration model and a two-layered turbid medium model are applied widely. In this paper, we set up the steady-state photon diffusion model of three-layered mismatched medium. We utilize the diffuse equation to solve a three-layered mismatched medium and obtain the accurate solution of a three-layered mismatched medium of the steady state in tissue. We find that the solution of a three-layered mismatched medium diffusion equation not only accord with the Monte-Carlo simulation, but can still solve the problems of a two-layered turbid medium model.

Hyperspectral image can be analyzed by Convex Geometry Analysis(CGA) method. CGA method can unmix... more Hyperspectral image can be analyzed by Convex Geometry Analysis(CGA) method. CGA method can unmix endmembers from hyperspectral image. The endmember proportions of mixed pixels can be calculated in inherent dimensional space, and a proportion image, which is called inherent proportion image, is obtained. The endmember proportions of mixed pixels can be calculated in n-space by the Constrained Least Squares, and a proportion image, which is called CLS proportion image, is obtained. In this paper, the inherent proportion image and CLS proportion image of a 30-band remote sensing image are obtained. The two proportion images are similar. The targets that are smaller than earth surface pixel can be identified by the inherent proportion image.