The aqueous polymerization of acrylamide and crosslinking with N,N-methylenebisacrylamide afforded hydrogelsdisplaying high levels of light scattering (poor optical clarity). Enhancement of the optical clarity within ...The aqueous polymerization of acrylamide and crosslinking with N,N-methylenebisacrylamide afforded hydrogelsdisplaying high levels of light scattering (poor optical clarity). Enhancement of the optical clarity within a polyacrylamide(PAm) hydrogel was accomplished through the implementation of 'refractive index matching'. Water-soluble additives wereutilised to better match the refractive index inhomogeneities throughout a given hydrogel. This resulted in lower lightscattering within the system and hence improved clarity. Amino acids, sugars, polymers, and other water-soluble additivessuch as glycerol were investigated by this methodology. Most additives investigaed displayed potential for effectivelyreducing the light scattering within a PAm hydrogel as a function of increased additive concentration. On increasing therefractive index of the water medium, the overall refractive index of a PAm hydrogel was also observed to increase. Thisprovided a quantitative means of determining the effectiveness of a given additive for improving the optical clarity within ahydrogel.展开更多
Optical immersion clearing is a technique that has been widely studied for more than two decades and that is used to originate a temporary transparency effect in biological tissues.If applied in cooperation with clini...Optical immersion clearing is a technique that has been widely studied for more than two decades and that is used to originate a temporary transparency effect in biological tissues.If applied in cooperation with clinical methods it provides optimization of diagnosis and treatment procedures.This technique turns biological tissues more transparent through two main mechanisms-tissue dehydration and refractive index(RI)matching between tissue compo-nents.Such matching is obtained by partial replacement of interstit ial water by a biocompat ible agent that presents higher RI and it can be completely rever sible by natural rehydration in vrivo or by assisted rehydration in ex vivo tissues.Experimental data to characterize and discriminate between the two mechanisms and to find new ones are necessary.Using a simple method,based on collimated transmittance and thickness measurements made from muscle samples under treatment,we have estimated the diffusion properties of glucose,ethylene glycol(EG)and water that were used to perform such char acterization and discrimination.Comparing these properties with data from literature that characterize their diffusion in water we have observed that musde cell membrane permeability limits agent and water diffusion in the muscle.The same experi-mental data has allowed to calculate the optical dearing(OC)eficiency and make an inter-pretation of the internal changes that occurred in muscle during the treatments.The same methodology can now be used to perform similar studies with other agents and in other tissues in order to solve engineering problems at design of inexpensive and robust technologies for a consider.able improvement of optical tomogr aphic techmiques with better contrast and in depth imaging.展开更多
Self-excited oscillation in a collapsible tube is an important phenomenon in physiology. An experimental approach on self-excited oscillation in a thin-walled collapsi- ble tube is developed by using a high transmitta...Self-excited oscillation in a collapsible tube is an important phenomenon in physiology. An experimental approach on self-excited oscillation in a thin-walled collapsi- ble tube is developed by using a high transmittance and low Young's modulus silicone rubber tube. The elastic tube is manufactured by the method of centrifugal casting in our laboratory. An optical method for recording the evolution of the cross-sectional areas at a certain position along the longitudinal direction of the tube is developed based on the technology of refractive index matching. With the transparent tube, the tube law is measured under the static no-flow condition. The cross section at the middle position of the tube transfers from a quasi-circular configuration to an ellipse, and then to a dumbell-shape as the chamber pressure is increased. During the self-excited oscillation, two periodic self-excited oscillating states and one transitional oscillating state are identified. They all belong to the LU mode. These different oscillating states are related to the initial cross-sectional shape of the tube caused by the difference of the downstream transmural pressure.展开更多
A 1.34 GHz-1=60 MHz low noise amplifier (LNA) designed in a 0.35 pm SiGe process is presented. The designed LNA exhibits a power gain of 21.46 dB and a noise figure (NF) of 1.27 dB at 1.34 GHz. The linearity is im...A 1.34 GHz-1=60 MHz low noise amplifier (LNA) designed in a 0.35 pm SiGe process is presented. The designed LNA exhibits a power gain of 21.46 dB and a noise figure (NF) of 1.27 dB at 1.34 GHz. The linearity is improved with an active biasing technique. The post-layout simulation shows an input referred 1-dB compression point (IPldn) of-11.52 dBm. Compared with the recent reported high gain LNAs, the proposed LNA has a much better linearity without degrading other performance. The LNA draws 10 mA current from a 3.3 V power supply.展开更多
High transparency and toughness are prerequisites for sustainable polymers if they are to find wide application as alternatives to petroleum-based polymers.However,the utility of sustainable polymers such as commercia...High transparency and toughness are prerequisites for sustainable polymers if they are to find wide application as alternatives to petroleum-based polymers.However,the utility of sustainable polymers such as commercially available polylactide(PLA)is limited by their inherent brittleness and high cost.Unfortunately,toughening PLA-based materials via cost-effective blending strategies without sacrificing transparency remains a challenge.Herein,we report a novel strategy involving active refractive index matching for creation of highly transparent and tough PLA blends.Specifically,we engineered the refractive index of a promising renewable poly(epichlorohydrin-co-ethylene oxide)elastomer by introducing polar ionic moieties via a simple chemical method,and we blended the resulting ionomers with PLA.The best blend showed an impact strength of>80 kJ/m2,an elongation at break of 400%,and high transparency(90%).These characteristics are of great importance for potential applications such as packaging.Our strategy offers a versatile new way to prepare high-performance sustainable polymer materials with excellent transparency.展开更多
In this paper,the internal flow field in a centrifugal pump working at the design flow rate operating condition has been measured using the particle image velocimetry(PIV)technique with the fluorescent particles and t...In this paper,the internal flow field in a centrifugal pump working at the design flow rate operating condition has been measured using the particle image velocimetry(PIV)technique with the fluorescent particles and the index-matched fluid technology.The index-marching fluid with the same refractive index as the transparent material has been prepared and applied in the present test of pump with geometrical complex walls.The comparison between velocity distributions of PIV results both with and without fluorescent particles,as well as with and without index-marching fluid are conducted to find the differences.The DES(Detached Eddy Simulation)has been employed to calculate the three-dimensional unsteady turbulent flow in the pump to examine and to certify the PIV measurement results.The DES results of instantaneous flow velocity fields agree with PIV test results with fluorescent particles and index-marching fluid.It is necessary to perform the PIV measurement of pumps with fluorescent seeds and index-marching fluid in order to get exact results.The experimental results show the distributions of velocity,steamlines,and the principal Reynolds normal stress(PRNS)and the principal Reynolds shear stress(PRSS).展开更多
Improving the accuracy of shape sensors based on multicore fibers(MCFs)is challenging but of great importance for real-time 3D shape detection,especially in visually inaccessible areas.In this work,a novel approach is...Improving the accuracy of shape sensors based on multicore fibers(MCFs)is challenging but of great importance for real-time 3D shape detection,especially in visually inaccessible areas.In this work,a novel approach is proposed to improve MCF shape sensor accuracy using an ultraviolet transparent liquid mediated fiber Bragg grating(FBG)inscription technique and a twist-isolating packaging method.A newly developed UV index matching liquid(UV-IML)is used to generate uniform light field at all the MCF cores,enabling FBG inscription with high accuracy.Additionally,a new stress fully released(SFR)packaging method is implemented to isolate the sensor from any external twists.The MCF shape sensor shows a maximum relative error of only 3.33%and the lowest reported relative sensitivity error of 1.11%cm^(-1).Moreover,a real-time 3D shape sensing system with a response frequency larger than 30 Hz is constructed using the unique MCF shape sensor.The highly accurate real-time 3D shape sensing results indicate potential applications for in vivo shape estimation of endoscopies and soft robots.展开更多
基金This work was financially supported through a sub-contract from Syracuse University under contract F30602-98C-0105
文摘The aqueous polymerization of acrylamide and crosslinking with N,N-methylenebisacrylamide afforded hydrogelsdisplaying high levels of light scattering (poor optical clarity). Enhancement of the optical clarity within a polyacrylamide(PAm) hydrogel was accomplished through the implementation of 'refractive index matching'. Water-soluble additives wereutilised to better match the refractive index inhomogeneities throughout a given hydrogel. This resulted in lower lightscattering within the system and hence improved clarity. Amino acids, sugars, polymers, and other water-soluble additivessuch as glycerol were investigated by this methodology. Most additives investigaed displayed potential for effectivelyreducing the light scattering within a PAm hydrogel as a function of increased additive concentration. On increasing therefractive index of the water medium, the overall refractive index of a PAm hydrogel was also observed to increase. Thisprovided a quantitative means of determining the effectiveness of a given additive for improving the optical clarity within ahydrogel.
基金support from the Government of Russian Federation(Grant No.14.Z50.31.0004)The Tomsk State University Academic D.I.Mendeleev Fund Program.
文摘Optical immersion clearing is a technique that has been widely studied for more than two decades and that is used to originate a temporary transparency effect in biological tissues.If applied in cooperation with clinical methods it provides optimization of diagnosis and treatment procedures.This technique turns biological tissues more transparent through two main mechanisms-tissue dehydration and refractive index(RI)matching between tissue compo-nents.Such matching is obtained by partial replacement of interstit ial water by a biocompat ible agent that presents higher RI and it can be completely rever sible by natural rehydration in vrivo or by assisted rehydration in ex vivo tissues.Experimental data to characterize and discriminate between the two mechanisms and to find new ones are necessary.Using a simple method,based on collimated transmittance and thickness measurements made from muscle samples under treatment,we have estimated the diffusion properties of glucose,ethylene glycol(EG)and water that were used to perform such char acterization and discrimination.Comparing these properties with data from literature that characterize their diffusion in water we have observed that musde cell membrane permeability limits agent and water diffusion in the muscle.The same experi-mental data has allowed to calculate the optical dearing(OC)eficiency and make an inter-pretation of the internal changes that occurred in muscle during the treatments.The same methodology can now be used to perform similar studies with other agents and in other tissues in order to solve engineering problems at design of inexpensive and robust technologies for a consider.able improvement of optical tomogr aphic techmiques with better contrast and in depth imaging.
基金support from the National Nature Science Foundation of China (Grants 11372305 and 11002138)K.C. Wong Education Foundation for a Royal Society K.C. Wong Postdoctoral Fellowship
文摘Self-excited oscillation in a collapsible tube is an important phenomenon in physiology. An experimental approach on self-excited oscillation in a thin-walled collapsi- ble tube is developed by using a high transmittance and low Young's modulus silicone rubber tube. The elastic tube is manufactured by the method of centrifugal casting in our laboratory. An optical method for recording the evolution of the cross-sectional areas at a certain position along the longitudinal direction of the tube is developed based on the technology of refractive index matching. With the transparent tube, the tube law is measured under the static no-flow condition. The cross section at the middle position of the tube transfers from a quasi-circular configuration to an ellipse, and then to a dumbell-shape as the chamber pressure is increased. During the self-excited oscillation, two periodic self-excited oscillating states and one transitional oscillating state are identified. They all belong to the LU mode. These different oscillating states are related to the initial cross-sectional shape of the tube caused by the difference of the downstream transmural pressure.
文摘A 1.34 GHz-1=60 MHz low noise amplifier (LNA) designed in a 0.35 pm SiGe process is presented. The designed LNA exhibits a power gain of 21.46 dB and a noise figure (NF) of 1.27 dB at 1.34 GHz. The linearity is improved with an active biasing technique. The post-layout simulation shows an input referred 1-dB compression point (IPldn) of-11.52 dBm. Compared with the recent reported high gain LNAs, the proposed LNA has a much better linearity without degrading other performance. The LNA draws 10 mA current from a 3.3 V power supply.
基金supported by the National Natural Science Foundation of China(No.51573130)。
文摘High transparency and toughness are prerequisites for sustainable polymers if they are to find wide application as alternatives to petroleum-based polymers.However,the utility of sustainable polymers such as commercially available polylactide(PLA)is limited by their inherent brittleness and high cost.Unfortunately,toughening PLA-based materials via cost-effective blending strategies without sacrificing transparency remains a challenge.Herein,we report a novel strategy involving active refractive index matching for creation of highly transparent and tough PLA blends.Specifically,we engineered the refractive index of a promising renewable poly(epichlorohydrin-co-ethylene oxide)elastomer by introducing polar ionic moieties via a simple chemical method,and we blended the resulting ionomers with PLA.The best blend showed an impact strength of>80 kJ/m2,an elongation at break of 400%,and high transparency(90%).These characteristics are of great importance for potential applications such as packaging.Our strategy offers a versatile new way to prepare high-performance sustainable polymer materials with excellent transparency.
基金supported by the National Natural Science Foundation of China(Grant No.10532010)
文摘In this paper,the internal flow field in a centrifugal pump working at the design flow rate operating condition has been measured using the particle image velocimetry(PIV)technique with the fluorescent particles and the index-matched fluid technology.The index-marching fluid with the same refractive index as the transparent material has been prepared and applied in the present test of pump with geometrical complex walls.The comparison between velocity distributions of PIV results both with and without fluorescent particles,as well as with and without index-marching fluid are conducted to find the differences.The DES(Detached Eddy Simulation)has been employed to calculate the three-dimensional unsteady turbulent flow in the pump to examine and to certify the PIV measurement results.The DES results of instantaneous flow velocity fields agree with PIV test results with fluorescent particles and index-marching fluid.It is necessary to perform the PIV measurement of pumps with fluorescent seeds and index-marching fluid in order to get exact results.The experimental results show the distributions of velocity,steamlines,and the principal Reynolds normal stress(PRNS)and the principal Reynolds shear stress(PRSS).
基金Major Scientific Research Project of Zhejiang Laboratory(No.2019MC0AD02)Innovation Project of Zhejiang Laboratory(No.2022MG0AL03)+1 种基金National Science Foundation of China(Nos.62204230,62020106002,T2293750,62205306,92250304)National Key Research and Development Program of China(2021YFC2401403)。
文摘Improving the accuracy of shape sensors based on multicore fibers(MCFs)is challenging but of great importance for real-time 3D shape detection,especially in visually inaccessible areas.In this work,a novel approach is proposed to improve MCF shape sensor accuracy using an ultraviolet transparent liquid mediated fiber Bragg grating(FBG)inscription technique and a twist-isolating packaging method.A newly developed UV index matching liquid(UV-IML)is used to generate uniform light field at all the MCF cores,enabling FBG inscription with high accuracy.Additionally,a new stress fully released(SFR)packaging method is implemented to isolate the sensor from any external twists.The MCF shape sensor shows a maximum relative error of only 3.33%and the lowest reported relative sensitivity error of 1.11%cm^(-1).Moreover,a real-time 3D shape sensing system with a response frequency larger than 30 Hz is constructed using the unique MCF shape sensor.The highly accurate real-time 3D shape sensing results indicate potential applications for in vivo shape estimation of endoscopies and soft robots.