We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chain...We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.展开更多
The VTLLS microscopy studies were made on high purity gold and commercial grade zinc grains in a temperature range of 30-230?C. Differential area ω and surface activity Sa were estimated from photomicrographs. The ω...The VTLLS microscopy studies were made on high purity gold and commercial grade zinc grains in a temperature range of 30-230?C. Differential area ω and surface activity Sa were estimated from photomicrographs. The ω vs dT/dt (rate of heating) curve was seen to differ from those of silver and titanium. The nature of curve between normalized ω and dT/dt was seen to be non-exponential. The characteristic relation between sectorized differential area ωsec and mean temperature was examined. The present study further establishes the simplicity and versatility of the VTLLS technique, in studying the defect-sub-structure of metal particles such as Au and Zn in presence of an imposed temperature gradient in a reasonable way. As such an attempt was made to connect the ω and defect-sub-structure related parameters.展开更多
Silver halide (AgX) microcrystal was used as template to synthesize hollow polyelectrolyte capsules. These hollow capsules were characterized by laser light scattering (LLS) used to measure the size of the capsules in...Silver halide (AgX) microcrystal was used as template to synthesize hollow polyelectrolyte capsules. These hollow capsules were characterized by laser light scattering (LLS) used to measure the size of the capsules in solution. The ratio of hydrodynamic radius (R h ) from dynamic LLS to the radius of gyration (Rg) from static LLS is almost unity, revealing that the entities are hollow in solution. The results suggest that the LLS method can be regarded as a good complement to the confocal laser scanning microscopy (CLSM) method for the characterization of small hollow capsules, and it possesses the advantage of not needing fluorescence labeling.展开更多
Durable press finishing of cotton fabrics with polycarboxylic acid increases fabric wrinkle-resistance at the expense of its mechanical strength. Severe tensile strength loss is the major disadvantage for wrinkle resi...Durable press finishing of cotton fabrics with polycarboxylic acid increases fabric wrinkle-resistance at the expense of its mechanical strength. Severe tensile strength loss is the major disadvantage for wrinkle resistant cotton fabrics.Tensile strength loss of cotton fabric crosslinked by a polycarboxylic acid can be attributed to depolymerization and crosslink of cellulose molecules. Measurement of the molecular weight of cotton fabric before and after crosslinked by polycarboxylic acids can offer a possibility of direct understanding of the depolymerization. In this research, amultiple angle laser light scattering photometer was used todetermine the absolute molecular weight of cotton fabric treated with BTCA at different pH and then hydrolyzed with 0. 5 M NaOH solution at 50℃ for 144 h. The results indicate that average molecular weights of cotton fabric treated with polycarboxylic acids at different pH are almost the same.展开更多
A circulating flow system consisting of a transparent U-bend flow loop, a mixing tank and a laser granulometer was set up for studying the kinetics hydrate formation and the pressure is up to 4 MPa. Refrigerant CCl2F2...A circulating flow system consisting of a transparent U-bend flow loop, a mixing tank and a laser granulometer was set up for studying the kinetics hydrate formation and the pressure is up to 4 MPa. Refrigerant CCl2F2 (R12) hydrate formation experiments were performed using laser light scattering method at 277.1 K and pressures of 0.24 and 0.32 MPa. The liquid flow rates were in the range of 300—1400 L/h. The size distribution and density of R12 hydrate particles in pure water were measured using a laser granulometer. Experimental results show that the size of hydrate particles increases sharply at the initial stage and approaches gradually to a stable size. The hydrate particle concentration in the aqueous phase increases with pressure and circulating liquid flow rate. Based on the material balance, the mathematical model among gas consumption, average hydrate particle size and shading ratio has been established. The calculated results using the mathematical model accord well with the experimental gas consumption data.展开更多
The principle of the technique of microscope laser light scattering spectroscopy, its development and applications to the studies on single intact cells, including our work on non-invasive in situ real time measuremen...The principle of the technique of microscope laser light scattering spectroscopy, its development and applications to the studies on single intact cells, including our work on non-invasive in situ real time measurements on single intact erythrocyte simultaneously at the levels of cellular, sub-cellular and intracellular molecules, are introduced.展开更多
The rapid detection of microparticles exhibits a broad range of applications in the field of science and technology. The proposed method differentiates and identifies the 2 μm and 5 μm sized particles using a laser ...The rapid detection of microparticles exhibits a broad range of applications in the field of science and technology. The proposed method differentiates and identifies the 2 μm and 5 μm sized particles using a laser light scattering. The detection method is based on measuring forward light scattering from the particles and then classifying the acquired data using support vector machines. The device is composed of a microfluidic chip linked with photosensors and a laser device using optical fiber. Connecting the photosensors and laser device using optical fibers makes the device more diminutive in size and portable. The prepared sample containing microspheres was passed through the channel, and the surrounding photosensors measured the scattered light. The time-domain features were evaluated from the acquired scattered light, and then the SVM classifier was trained to distinguish the particle’s data. The real-time detection of the particles was performed with an overall classification accuracy of 96.06%. The optimum conditions were evaluated to detect the particles with a minimum concentration of 0.2 μg/m L. The developed system is anticipated to be helpful in developing rapid testing devices for detecting pathogens ranging between 2 μm to 10 μm.展开更多
Surface-enhanced Raman scattering(SERS) has been widely used as an effective technique for lowconcentration molecules detections in the past decades. This work proposes a rapid and accessible process to fabricate SERS...Surface-enhanced Raman scattering(SERS) has been widely used as an effective technique for lowconcentration molecules detections in the past decades. This work proposes a rapid and accessible process to fabricate SERS-active substrates with high uniformity and controllability based on two-step laser ablation. Laser beams directly ablate the surface of Si, concurrently creating microstructures and ejecting molten materials caused by the thermal effect that nucleate in ambient air. The nuclei grow into nanoparticles and deposit over the surface. These nanoparticles,together with microstructures, improve the light collection efficiency of the SERS-active substrates. Especially after Au thin film deposition, these nanoparticles can provide nanogaps as hotspots for SERS. By orthogonal experiment design,laser processing parameters for better performances are determined. Compared with substrates fabricated by single 1064 nm master oscillator power amplifier(MOPA) laser ablation, substrates ablated by the primary 1064 nm MOPA laser and secondary UV pulsed laser show more uniform nanoparticles’ deposition over the surface. The optimized largearea substrate has a SERS detection limit of 10^(-8)mol/L for 4-aminothiophenol(4-ATP), indicating the potential realworld applications for trace detection.展开更多
This review covers the progress of light scattering applications in the field of particle characterization in the past decade. The review addresses static light scattering （the measurement of scattering intensities d...This review covers the progress of light scattering applications in the field of particle characterization in the past decade. The review addresses static light scattering （the measurement of scattering intensities due to light-particle interaction at various spatial locations）, dynamic light scattering （the measurement of scattering due to light-particle interaction as a function of time）, and scattering tracking analysis （the tracking of particle movement through scattering measurement）.展开更多
We investigate the stimulated Brillouin scattering （SBS） properties of light beams carrying orbit angular momentum （OAM）. The phase conjugation of light beams carrying OAM is experimentally achieved in an SBS mirr...We investigate the stimulated Brillouin scattering （SBS） properties of light beams carrying orbit angular momentum （OAM）. The phase conjugation of light beams carrying OAM is experimentally achieved in an SBS mirror with a random phase plate. The spectrum and the pulse width compression of SBS light are measured. It is shown that the phenomena of pulse compression is observed and OAM conservation is confirmed in the SBS process. The OAM transfer from photons to phonons may find potential applications in photon-phonon conversion-based signal-processing schemes by using OAM multiplexing.展开更多
基金ACKNOWLEDGMENTS This work was supported by China Tobacco Guangdong Industrial Co., Ltd., National Natural Science Foundation of China （No21234003 and No.51303059）, and the Fundamental Research Funds for Central Universities.
文摘We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.
文摘The VTLLS microscopy studies were made on high purity gold and commercial grade zinc grains in a temperature range of 30-230?C. Differential area ω and surface activity Sa were estimated from photomicrographs. The ω vs dT/dt (rate of heating) curve was seen to differ from those of silver and titanium. The nature of curve between normalized ω and dT/dt was seen to be non-exponential. The characteristic relation between sectorized differential area ωsec and mean temperature was examined. The present study further establishes the simplicity and versatility of the VTLLS technique, in studying the defect-sub-structure of metal particles such as Au and Zn in presence of an imposed temperature gradient in a reasonable way. As such an attempt was made to connect the ω and defect-sub-structure related parameters.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 20204017 and 50373049) and theChinese Academy of Sciences (CMS-CX200308).
文摘Silver halide (AgX) microcrystal was used as template to synthesize hollow polyelectrolyte capsules. These hollow capsules were characterized by laser light scattering (LLS) used to measure the size of the capsules in solution. The ratio of hydrodynamic radius (R h ) from dynamic LLS to the radius of gyration (Rg) from static LLS is almost unity, revealing that the entities are hollow in solution. The results suggest that the LLS method can be regarded as a good complement to the confocal laser scanning microscopy (CLSM) method for the characterization of small hollow capsules, and it possesses the advantage of not needing fluorescence labeling.
基金The Project-sponsored by SRF for ROCS, SEM and EYTP of MOE
文摘Durable press finishing of cotton fabrics with polycarboxylic acid increases fabric wrinkle-resistance at the expense of its mechanical strength. Severe tensile strength loss is the major disadvantage for wrinkle resistant cotton fabrics.Tensile strength loss of cotton fabric crosslinked by a polycarboxylic acid can be attributed to depolymerization and crosslink of cellulose molecules. Measurement of the molecular weight of cotton fabric before and after crosslinked by polycarboxylic acids can offer a possibility of direct understanding of the depolymerization. In this research, amultiple angle laser light scattering photometer was used todetermine the absolute molecular weight of cotton fabric treated with BTCA at different pH and then hydrolyzed with 0. 5 M NaOH solution at 50℃ for 144 h. The results indicate that average molecular weights of cotton fabric treated with polycarboxylic acids at different pH are almost the same.
基金This work was supported by the National 973 of China(Grant No.2001CB209107) National 863 of China(Grant No.2002AA615120).
文摘A circulating flow system consisting of a transparent U-bend flow loop, a mixing tank and a laser granulometer was set up for studying the kinetics hydrate formation and the pressure is up to 4 MPa. Refrigerant CCl2F2 (R12) hydrate formation experiments were performed using laser light scattering method at 277.1 K and pressures of 0.24 and 0.32 MPa. The liquid flow rates were in the range of 300—1400 L/h. The size distribution and density of R12 hydrate particles in pure water were measured using a laser granulometer. Experimental results show that the size of hydrate particles increases sharply at the initial stage and approaches gradually to a stable size. The hydrate particle concentration in the aqueous phase increases with pressure and circulating liquid flow rate. Based on the material balance, the mathematical model among gas consumption, average hydrate particle size and shading ratio has been established. The calculated results using the mathematical model accord well with the experimental gas consumption data.
文摘The principle of the technique of microscope laser light scattering spectroscopy, its development and applications to the studies on single intact cells, including our work on non-invasive in situ real time measurements on single intact erythrocyte simultaneously at the levels of cellular, sub-cellular and intracellular molecules, are introduced.
基金supported by the Natural Science Youth Foundation of China (No. 61801307)the Scientific ResearchFund of the Shenzhen International Cooperation Projects (No.GJHZ20190819151403615)。
文摘The rapid detection of microparticles exhibits a broad range of applications in the field of science and technology. The proposed method differentiates and identifies the 2 μm and 5 μm sized particles using a laser light scattering. The detection method is based on measuring forward light scattering from the particles and then classifying the acquired data using support vector machines. The device is composed of a microfluidic chip linked with photosensors and a laser device using optical fiber. Connecting the photosensors and laser device using optical fibers makes the device more diminutive in size and portable. The prepared sample containing microspheres was passed through the channel, and the surrounding photosensors measured the scattered light. The time-domain features were evaluated from the acquired scattered light, and then the SVM classifier was trained to distinguish the particle’s data. The real-time detection of the particles was performed with an overall classification accuracy of 96.06%. The optimum conditions were evaluated to detect the particles with a minimum concentration of 0.2 μg/m L. The developed system is anticipated to be helpful in developing rapid testing devices for detecting pathogens ranging between 2 μm to 10 μm.
基金Project(2020H0006) supported by the Fujian Provincial Science and Technology ProgrammeChina+2 种基金Project(62175203) supported by the National Natural Science Foundation of ChinaProject(RD2020050301) supported by the Innovation Laboratory for Science and Technology of Energy Materials of Fujian Province Applied Research ProjectChina。
文摘Surface-enhanced Raman scattering(SERS) has been widely used as an effective technique for lowconcentration molecules detections in the past decades. This work proposes a rapid and accessible process to fabricate SERS-active substrates with high uniformity and controllability based on two-step laser ablation. Laser beams directly ablate the surface of Si, concurrently creating microstructures and ejecting molten materials caused by the thermal effect that nucleate in ambient air. The nuclei grow into nanoparticles and deposit over the surface. These nanoparticles,together with microstructures, improve the light collection efficiency of the SERS-active substrates. Especially after Au thin film deposition, these nanoparticles can provide nanogaps as hotspots for SERS. By orthogonal experiment design,laser processing parameters for better performances are determined. Compared with substrates fabricated by single 1064 nm master oscillator power amplifier(MOPA) laser ablation, substrates ablated by the primary 1064 nm MOPA laser and secondary UV pulsed laser show more uniform nanoparticles’ deposition over the surface. The optimized largearea substrate has a SERS detection limit of 10^(-8)mol/L for 4-aminothiophenol(4-ATP), indicating the potential realworld applications for trace detection.
文摘This review covers the progress of light scattering applications in the field of particle characterization in the past decade. The review addresses static light scattering （the measurement of scattering intensities due to light-particle interaction at various spatial locations）, dynamic light scattering （the measurement of scattering due to light-particle interaction as a function of time）, and scattering tracking analysis （the tracking of particle movement through scattering measurement）.
基金supported by the National Natural Science Foundation of China(Nos.61605049,61575070,and 11674111)the Fujian Province Science Fund for Distinguished Young Scholars(No.2015J06015)
文摘We investigate the stimulated Brillouin scattering （SBS） properties of light beams carrying orbit angular momentum （OAM）. The phase conjugation of light beams carrying OAM is experimentally achieved in an SBS mirror with a random phase plate. The spectrum and the pulse width compression of SBS light are measured. It is shown that the phenomena of pulse compression is observed and OAM conservation is confirmed in the SBS process. The OAM transfer from photons to phonons may find potential applications in photon-phonon conversion-based signal-processing schemes by using OAM multiplexing.
