Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the t...Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices.展开更多
We present an experimental and theoretical investigation of the coherent population trapping （CPT） resonance excited on the D1 line of 87Rb atoms by bichromatic linearly polarized laser light. The experimental resul...We present an experimental and theoretical investigation of the coherent population trapping （CPT） resonance excited on the D1 line of 87Rb atoms by bichromatic linearly polarized laser light. The experimental results show that a lin｜｜lin tran- sition scheme is a promising alternative to the conventional circular-circular transition scheme for an atomic magnetometer. Compared with the circular light transition scheme, linear light accounts for high-contrast transmission resonances, which makes this excitation scheme promising for high-sensitivity magnetometers. We also use linear light and circular light to detect changes of a standard magnetic field, separately.展开更多
A prototype of a laser driven proton accelerator is built at Peking University. Protons exceeding IOMeV are accelerated from micrometer-thick aluminum targets irradiated by tightly focused laser pulse with 1.8 J energ...A prototype of a laser driven proton accelerator is built at Peking University. Protons exceeding IOMeV are accelerated from micrometer-thick aluminum targets irradiated by tightly focused laser pulse with 1.8 J energy and 30fs duration. The beam energy spectrum and charge distribution are measured by a Thomson parabola spectrometer and radiochromic fihn stacks. The sensitivity of proton cut-off energy to the focusing of the laser beam, the pulse duration, and the foil thickness are systematically investigated in the experiments. Stable proton beams have been produced with an optimized parameter set, providing a cornerstone for the future applications of laser accelerated protons.展开更多
we preset the design and rabrication of a novel auai-iunction hign contrast gratings that can De usea as a polarizationselective beam splitter with transverse magnetic polarization,which performs two independent funct...we preset the design and rabrication of a novel auai-iunction hign contrast gratings that can De usea as a polarizationselective beam splitter with transverse magnetic polarization,which performs two independent functions,i.e.,reflection focusing and power equalization at a wavelength of 1550 nm.This dual-function grating profile is optimized by the rigorous coupled-wave analysis and the finite-element method.Simple analytical expressions of phase and modal guideline for the beam splitter design are given.The beam splitter based on the grating structure is experimentally studied at a distance of 160 μm from the reflection plane,the results are consistent with the theoretical results basically.展开更多
We demonstrate a high-quality cross-polarized-wave filter based on spectral phase modulation. Driven by Well- eompressed spectral-phase fully-compensated fundamental laser lmlses, the filter stretches the pulse bandwi...We demonstrate a high-quality cross-polarized-wave filter based on spectral phase modulation. Driven by Well- eompressed spectral-phase fully-compensated fundamental laser lmlses, the filter stretches the pulse bandwidth from 35 nm to 7Ohm with a conversion efficeiency of 20%.展开更多
The low signal-to-noise ratio(S/N)and single functionality of fluorescence imaging agents have limited their practical applications.Bright two-photon excitation(2PE)imaging probes are highly desirable in vivo with lar...The low signal-to-noise ratio(S/N)and single functionality of fluorescence imaging agents have limited their practical applications.Bright two-photon excitation(2PE)imaging probes are highly desirable in vivo with larger imaging depth,minor autofluorescence background,and less photodamage.Herein,we developed responsive aggregated gold nanoparticles(Au NPs)as high contrast 2PE imaging agents,capable of emitting red fluorescence upon excitation of near-infrared(NIR)laser and possessing a high signal-to-noise ratio(S/N of 2,475).By forming aggregates in situ inside tumor tissue,doxorubicin hydrochloride(DOX)-loaded mix-charged gold nanoparticles(DOX-MC-Au NPs)were utilized to act as selective fluorescence imaging probes and precise therapy agents.These high-contrast theranostic agents offer a promising potential for precise cancer imaging and therapy,which might open a new venue to multifunctional and noninvasive theranostics.展开更多
The development of new carbon dots(CDs)for fluorescence-based cancer diagnosis has recently attracted extensive attention.Diagnosis methods based on ligand-receptor fluorescence suffer from the heterogeneity of recept...The development of new carbon dots(CDs)for fluorescence-based cancer diagnosis has recently attracted extensive attention.Diagnosis methods based on ligand-receptor fluorescence suffer from the heterogeneity of receptor expression.Changes in the microenvironments of cancer cells provide opportunities for accurate and broad-spectrum cancer diagnosis.The lysosomes in cancer cells have lower polarity and higher viscosity than normal cells.Based on these two key microenvironmental parameters,dual-responsive CDs with inherent lysosome-targeting ability were synthesized via one-step hydrothermal treatment.The CDs exhibit many advantageous properties including facile synthesis,good water solubility,pH-independent emission,excellent photostability,good biocompatibility,and wash-free imaging ability.The CDs were successfully employed in the fluorescence-based discrimination of a broad spectrum of cancer cells from normal cells with high contrast.The CDs are promising candidates for use in the field of cancer diagnosis.展开更多
Linearized approximations of reflection and transmission coefficients set a foundation for amplitude versus offset（AVO） analysis and inversion in exploration geophysics.However,the weak properties contrast hypothesi...Linearized approximations of reflection and transmission coefficients set a foundation for amplitude versus offset（AVO） analysis and inversion in exploration geophysics.However,the weak properties contrast hypothesis of those linearized approximate equations leads to big errors when the two media across the interface vary dramatically.To extend the application of AVO analysis and inversion to high contrast between the properties of the two layers,we derive a novel nonlinearized high-contrast approximation of the PP-wave reflection coefficient,which establishes the direct relationship between PPwave reflection coefficient and P-wave velocities,S-wave velocities and densities across the interface.（A PP wave is a reflected compressional wave from an incident compressional wave（P-wave）.） This novel approximation is derived from the exact reflection coefficient equation with Taylor expansion for the incident angle.Model tests demonstrate that,compared with the reflection coefficients of the linearized approximations,the reflection coefficients of the novel nonlinearized approximate equation agree with those of the exact PP equation better for a high contrast interface with a moderate incident angle.Furthermore,we introduce a nonlinear direct inversion method utilizing the novel reflection coefficient equation as forward solver,to implement the direct inversion for the six parameters including P-wave velocities,S-wave velocities,and densities in the upper and lower layers across the interface.This nonlinear inversion algorithm is able to estimate the inverse of the nonlinear function in terms of model parameters directly rather than in a conventional optimization way.Three examples verified the feasibility and suitability of this novel approximation for a high contrast interface,and we still could estimate the six parameters across the interface reasonably when the parameters in both media across the interface vary about 50%.展开更多
<strong>Objective:</strong> To explore the application value of high-frequency ultrasound and contrast-enhanced ultrasound in different syndrome types of knee osteoarthritis, and to provide more imaging ev...<strong>Objective:</strong> To explore the application value of high-frequency ultrasound and contrast-enhanced ultrasound in different syndrome types of knee osteoarthritis, and to provide more imaging evidence for clinical diagnosis and treatment. <strong>Method:</strong> Sixty patients with KOA were selected according to TCM classification, which were mainly divided into Qi stagnation and blood stasis type and cold-dampness blockage type. All knee joints were routinely examined by high frequency ultrasound, and those with synovial hyperplasia were examined by contrast-enhanced ultrasound. High frequency ultrasound is the examination of synovium, cartilage and collateral ligament of knee joint based on two-dimensional ultrasound. Contrast-enhanced ultrasound (CEUS) refers to the contrast examination of synovium in knee joint patients with synovial hyperplasia. <strong>Result: </strong>Among them, the suprapatellar sac effusion and synovial thickening of Qi stagnation and blood stasis type were more obvious than those of cold-dampness arthralgia type (P < 0.05), and the degree of wear of the intercondylar cartilage of cold-dampness arthralgia type was more obvious than that of Qi stagnation. The blood stasis type is heavier and the meniscus bulge is higher (P < 0.05). The radiography of synovial hyperplasia showed that the area under the curve of Qi stagnation and blood stasis type was higher than that of cold dampness arthralgia type (P < 0.05), and the peak time was significantly shorter than that of cold dampness arthralgia type. There was no statistical difference in effective peak gradient and onset time of type (P > 0.05). <strong>Conclusion: </strong>To a certain extent, the high-frequency ultrasound and contrast-enhanced ultrasound performance of knee osteoarthritis can be used as a dialectical reference for different TCM syndrome types.展开更多
Photoacoustic(PA) imaging has drawn tremendous research interest for various applications in biomedicine and experienced exponential growth over the past decade. Since the scattering effect of biological tissue on ult...Photoacoustic(PA) imaging has drawn tremendous research interest for various applications in biomedicine and experienced exponential growth over the past decade. Since the scattering effect of biological tissue on ultrasound is two-to three-orders magnitude weaker than that of light, photoacoustic imaging can effectively improve the imaging depth.However, as the depth of imaging further increases, the incident light is seriously affected by scattering that the generated photoacoustic signal is very weak and the signal-to-noise ratio(SNR) is quite low. Low SNR signals can reduce imaging quality and even cause imaging failure. In this paper, we proposed a new wavefront shaping and imaging method of low SNR photoacoustic signal using digital micromirror device(DMD) based superpixel method. We combined the superpixel method with DMD to modulate the phase and amplitude of the incident light, and the genetic algorithm(GA) was used as the wavefront shaping algorithm. The enhancement of the photoacoustic signal reached 10.46. Then we performed scanning imaging by moving the absorber with the translation stage. A clear image with contrast of 8.57 was obtained while imaging with original photoacoustic signals could not be achieved. The proposed method opens new perspectives for imaging with weak photoacoustic signals.展开更多
Starlight is generally unpolarized,but the light reflected from the planet is linearly polarized as the result of the Rayleigh scattering.For ground-based exoplanet imaging,atmospheres turbulence is changing from time...Starlight is generally unpolarized,but the light reflected from the planet is linearly polarized as the result of the Rayleigh scattering.For ground-based exoplanet imaging,atmospheres turbulence is changing from time to time,which induces speckle noise and hampers the high-contrast imaging of the faint exoplanets.In this paper,we propose a differential-imaging polarimeter dedicated for exoplanet high-contrast imaging.The system contains a zero-order half-wave plate(HWP)located on the optical pupil plane,which can rotate to modulate the incoming light,and a Wollaston prism(WP)is used to generate two polarized images,which is used for simultaneously polarization differential imaging and thus our system is fundamentally immune to the atmospheric turbulence induced temporally-variable wavefront aberration.Our polarimeter can be inserted near the telescope image focal plane,and provide an extra contrast for the exoplanet high-contrast imaging.To achieve best differential-imaging performance,dedicated algorithm is developed,which can effectively correct the distortion and the intensity unbalance between the two differential images.The system successfully achieves an extra contrast of^30~50 times,which can be used with current adaptive optics and coronagraph system for directly imaging of giant Jupiter-like exoplanets.展开更多
This study was undertaken to investigate the correlation of the enhancement degree on contrast-enhanced ultrasound(CEUS) with the histopathology of carotid plaques and the serum high sensitive C-reactive protein(hs-CR...This study was undertaken to investigate the correlation of the enhancement degree on contrast-enhanced ultrasound(CEUS) with the histopathology of carotid plaques and the serum high sensitive C-reactive protein(hs-CRP) levels in patients undergoing carotid endarterectomy(CEA). Carotid CEUS was performed preoperatively in 115 patients who would undergo CEA, and the enhancement degree of the carotid plaques was evaluated by both the visual semiquantitative analysis and the quantitative time-intensity curve analysis. Serum hs-CRP levels were detected using the particle-enhanced immunoturbidimetric assay also before the operation. Additionally, the carotid plaque samples were subjected to histopathological examination postoperatively. The density of neovessels and the number of macrophages in the plaques were assessed by immunohistochemistry. The results showed that among the 115 patients, grade 0 plaque contrast enhancement was noted in 35 patients, grade 1 in 48 patients and grade 2 in 32 patients. The degree of plaque enhancement, the density of neovessels, the number of macrophages, and the hs-CRP levels were highest in the grade 2 patients. Correlation analysis showed that the enhancement degree of the carotid plaques was closely related to the immunohistochemical parameters of the plaques and the serum hs-CRP levels. It was suggested that the carotid plaque enhancement on CEUS can be used to evaluate the vulnerability of carotid plaques.展开更多
基金Natural Science Foundation of Hebei Province(China),Grant/Award Numbers:B2020203013,B2021203016Science and Technology Project of Hebei Education Department(China),Grant/Award Number:QN2020137+3 种基金Cultivation Project for Basic Research Innovation of Yanshan University(China),Grant/Award Number:2021LGZD015Subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance(China),Grant/Award Number:22567616HNatural Science Foundation of Heilongjiang Province(China),Grant/Award Number:LH2022B025Fundamental Research Funds for the Provincial Universities of Heilongjiang Province(China),Grant/Award Number:KYYWF10236190104。
文摘Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices.
基金Project supported by the National Basic Research Program of China (Grant No.2013CB329501)the National Natural Science Foundation of China (Grant Nos.60925022 and 11125863)the Fundamental Research Funds for the Central Universities (Grant No.2012FZA3001)
文摘We present an experimental and theoretical investigation of the coherent population trapping （CPT） resonance excited on the D1 line of 87Rb atoms by bichromatic linearly polarized laser light. The experimental results show that a lin｜｜lin tran- sition scheme is a promising alternative to the conventional circular-circular transition scheme for an atomic magnetometer. Compared with the circular light transition scheme, linear light accounts for high-contrast transmission resonances, which makes this excitation scheme promising for high-sensitivity magnetometers. We also use linear light and circular light to detect changes of a standard magnetic field, separately.
基金Supported by the National Basic Research Program of China under Grant No 2013CBA01502the National Natural Science Foundation of China under Grant Nos 11475010,11575011 and 11535001the National Grand Instrument Project under Grant No 2012YQ030142
文摘A prototype of a laser driven proton accelerator is built at Peking University. Protons exceeding IOMeV are accelerated from micrometer-thick aluminum targets irradiated by tightly focused laser pulse with 1.8 J energy and 30fs duration. The beam energy spectrum and charge distribution are measured by a Thomson parabola spectrometer and radiochromic fihn stacks. The sensitivity of proton cut-off energy to the focusing of the laser beam, the pulse duration, and the foil thickness are systematically investigated in the experiments. Stable proton beams have been produced with an optimized parameter set, providing a cornerstone for the future applications of laser accelerated protons.
基金Project supported by the Open Fund of the State Key Laboratory of Information Photonics and Optical CommunicationBeijing University of Posts and Telecommunications,China(Grant No.IPOC2019A009)the National Natural Science Foundation of China(Grant Nos.61501214 and 61501213)。
文摘we preset the design and rabrication of a novel auai-iunction hign contrast gratings that can De usea as a polarizationselective beam splitter with transverse magnetic polarization,which performs two independent functions,i.e.,reflection focusing and power equalization at a wavelength of 1550 nm.This dual-function grating profile is optimized by the rigorous coupled-wave analysis and the finite-element method.Simple analytical expressions of phase and modal guideline for the beam splitter design are given.The beam splitter based on the grating structure is experimentally studied at a distance of 160 μm from the reflection plane,the results are consistent with the theoretical results basically.
基金Supported by the National Key Basic Research Program of China under Grant No 2013CB922402the National Natural Science Foundation of China under Grant Nos 61575217 and 11434016+1 种基金the Key Research Program of Frontier Sciences of Chinese Academy of Sciences under Grant Nos KJZD-EW-L11-03 and QYZDJ-SSW-JSC006the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No XDB16030200
文摘We demonstrate a high-quality cross-polarized-wave filter based on spectral phase modulation. Driven by Well- eompressed spectral-phase fully-compensated fundamental laser lmlses, the filter stretches the pulse bandwidth from 35 nm to 7Ohm with a conversion efficeiency of 20%.
基金supported by the Science and Technology Project of Jiangsu Province(BZ2022056)the Ministry of Education,Singapore(Tier 1 A-8000013-00-00)。
文摘The low signal-to-noise ratio(S/N)and single functionality of fluorescence imaging agents have limited their practical applications.Bright two-photon excitation(2PE)imaging probes are highly desirable in vivo with larger imaging depth,minor autofluorescence background,and less photodamage.Herein,we developed responsive aggregated gold nanoparticles(Au NPs)as high contrast 2PE imaging agents,capable of emitting red fluorescence upon excitation of near-infrared(NIR)laser and possessing a high signal-to-noise ratio(S/N of 2,475).By forming aggregates in situ inside tumor tissue,doxorubicin hydrochloride(DOX)-loaded mix-charged gold nanoparticles(DOX-MC-Au NPs)were utilized to act as selective fluorescence imaging probes and precise therapy agents.These high-contrast theranostic agents offer a promising potential for precise cancer imaging and therapy,which might open a new venue to multifunctional and noninvasive theranostics.
基金supported by the National Natural Science Foundation of China(Nos.21974125,21708035)Program for Innovative Research Team(in Science and Technology)in University of Henan Province(No.22TRTSTHN002)+1 种基金the 111 Project of Henan Province(No.CXJD2021001)National 111 Project(No.D20003).
文摘The development of new carbon dots(CDs)for fluorescence-based cancer diagnosis has recently attracted extensive attention.Diagnosis methods based on ligand-receptor fluorescence suffer from the heterogeneity of receptor expression.Changes in the microenvironments of cancer cells provide opportunities for accurate and broad-spectrum cancer diagnosis.The lysosomes in cancer cells have lower polarity and higher viscosity than normal cells.Based on these two key microenvironmental parameters,dual-responsive CDs with inherent lysosome-targeting ability were synthesized via one-step hydrothermal treatment.The CDs exhibit many advantageous properties including facile synthesis,good water solubility,pH-independent emission,excellent photostability,good biocompatibility,and wash-free imaging ability.The CDs were successfully employed in the fluorescence-based discrimination of a broad spectrum of cancer cells from normal cells with high contrast.The CDs are promising candidates for use in the field of cancer diagnosis.
基金the sponsorship of the National 973 Program of China (2013CB228604)the National Grand Project for Science and Technology (2011ZX05030-004-002, 2011ZX05019-003 and 2011ZX05006-002) for funding this research+2 种基金the support of the Australian and Western Australian Governments and the North West Shelf Joint Venture Partnersthe Western Australian Energy Research Alliance (WA:ERA)Foundation from Geophysical Key Lab of SINOPEC (WTYJYWX2013-04-01)
文摘Linearized approximations of reflection and transmission coefficients set a foundation for amplitude versus offset（AVO） analysis and inversion in exploration geophysics.However,the weak properties contrast hypothesis of those linearized approximate equations leads to big errors when the two media across the interface vary dramatically.To extend the application of AVO analysis and inversion to high contrast between the properties of the two layers,we derive a novel nonlinearized high-contrast approximation of the PP-wave reflection coefficient,which establishes the direct relationship between PPwave reflection coefficient and P-wave velocities,S-wave velocities and densities across the interface.（A PP wave is a reflected compressional wave from an incident compressional wave（P-wave）.） This novel approximation is derived from the exact reflection coefficient equation with Taylor expansion for the incident angle.Model tests demonstrate that,compared with the reflection coefficients of the linearized approximations,the reflection coefficients of the novel nonlinearized approximate equation agree with those of the exact PP equation better for a high contrast interface with a moderate incident angle.Furthermore,we introduce a nonlinear direct inversion method utilizing the novel reflection coefficient equation as forward solver,to implement the direct inversion for the six parameters including P-wave velocities,S-wave velocities,and densities in the upper and lower layers across the interface.This nonlinear inversion algorithm is able to estimate the inverse of the nonlinear function in terms of model parameters directly rather than in a conventional optimization way.Three examples verified the feasibility and suitability of this novel approximation for a high contrast interface,and we still could estimate the six parameters across the interface reasonably when the parameters in both media across the interface vary about 50%.
文摘<strong>Objective:</strong> To explore the application value of high-frequency ultrasound and contrast-enhanced ultrasound in different syndrome types of knee osteoarthritis, and to provide more imaging evidence for clinical diagnosis and treatment. <strong>Method:</strong> Sixty patients with KOA were selected according to TCM classification, which were mainly divided into Qi stagnation and blood stasis type and cold-dampness blockage type. All knee joints were routinely examined by high frequency ultrasound, and those with synovial hyperplasia were examined by contrast-enhanced ultrasound. High frequency ultrasound is the examination of synovium, cartilage and collateral ligament of knee joint based on two-dimensional ultrasound. Contrast-enhanced ultrasound (CEUS) refers to the contrast examination of synovium in knee joint patients with synovial hyperplasia. <strong>Result: </strong>Among them, the suprapatellar sac effusion and synovial thickening of Qi stagnation and blood stasis type were more obvious than those of cold-dampness arthralgia type (P < 0.05), and the degree of wear of the intercondylar cartilage of cold-dampness arthralgia type was more obvious than that of Qi stagnation. The blood stasis type is heavier and the meniscus bulge is higher (P < 0.05). The radiography of synovial hyperplasia showed that the area under the curve of Qi stagnation and blood stasis type was higher than that of cold dampness arthralgia type (P < 0.05), and the peak time was significantly shorter than that of cold dampness arthralgia type. There was no statistical difference in effective peak gradient and onset time of type (P > 0.05). <strong>Conclusion: </strong>To a certain extent, the high-frequency ultrasound and contrast-enhanced ultrasound performance of knee osteoarthritis can be used as a dialectical reference for different TCM syndrome types.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFB1104500)the Beijing Natural Science Foundation,China(Grant No.7182091)+1 种基金the National Natural Science Foundation of China(Grant No.21627813)the Research Projects on Biomedical Transformation of China–Japan Friendship Hospital(Grant No.PYBZ1801)。
文摘Photoacoustic(PA) imaging has drawn tremendous research interest for various applications in biomedicine and experienced exponential growth over the past decade. Since the scattering effect of biological tissue on ultrasound is two-to three-orders magnitude weaker than that of light, photoacoustic imaging can effectively improve the imaging depth.However, as the depth of imaging further increases, the incident light is seriously affected by scattering that the generated photoacoustic signal is very weak and the signal-to-noise ratio(SNR) is quite low. Low SNR signals can reduce imaging quality and even cause imaging failure. In this paper, we proposed a new wavefront shaping and imaging method of low SNR photoacoustic signal using digital micromirror device(DMD) based superpixel method. We combined the superpixel method with DMD to modulate the phase and amplitude of the incident light, and the genetic algorithm(GA) was used as the wavefront shaping algorithm. The enhancement of the photoacoustic signal reached 10.46. Then we performed scanning imaging by moving the absorber with the translation stage. A clear image with contrast of 8.57 was obtained while imaging with original photoacoustic signals could not be achieved. The proposed method opens new perspectives for imaging with weak photoacoustic signals.
基金the National Natural Science Foundation of China (NSFC, 11703058, 11703056, 11661161011, 11433007, 11220101001, 11328302, 11373005 and 11303064)the Opening Project of Key Laboratory of Astronomical Optics & Technology, Nanjing Institute of Astronomical Optics & Technology, Chinese Academy of Sciences (CASKLAOT-KF201606)+5 种基金the “Strategic Priority Research Program” of the ChineseAcademy of Sciences (XDA04075200)the Special Fund for astronomy of CAS (2015–2016)the Special Fund for Young Researcher of Nanjing Institute of Astronomical Optics & Technologythe International Partnership Program of the Chinese Academy of Sciences (114A32KYSB20160018)carried out at California State University Northridge with the support from NSF AST-1607921the Mt. Cuba Astronomical Foundation
文摘Starlight is generally unpolarized,but the light reflected from the planet is linearly polarized as the result of the Rayleigh scattering.For ground-based exoplanet imaging,atmospheres turbulence is changing from time to time,which induces speckle noise and hampers the high-contrast imaging of the faint exoplanets.In this paper,we propose a differential-imaging polarimeter dedicated for exoplanet high-contrast imaging.The system contains a zero-order half-wave plate(HWP)located on the optical pupil plane,which can rotate to modulate the incoming light,and a Wollaston prism(WP)is used to generate two polarized images,which is used for simultaneously polarization differential imaging and thus our system is fundamentally immune to the atmospheric turbulence induced temporally-variable wavefront aberration.Our polarimeter can be inserted near the telescope image focal plane,and provide an extra contrast for the exoplanet high-contrast imaging.To achieve best differential-imaging performance,dedicated algorithm is developed,which can effectively correct the distortion and the intensity unbalance between the two differential images.The system successfully achieves an extra contrast of^30~50 times,which can be used with current adaptive optics and coronagraph system for directly imaging of giant Jupiter-like exoplanets.
基金supported by the Natural Science Foundation of Zhejiang Province,China(No.LY13H180007)
文摘This study was undertaken to investigate the correlation of the enhancement degree on contrast-enhanced ultrasound(CEUS) with the histopathology of carotid plaques and the serum high sensitive C-reactive protein(hs-CRP) levels in patients undergoing carotid endarterectomy(CEA). Carotid CEUS was performed preoperatively in 115 patients who would undergo CEA, and the enhancement degree of the carotid plaques was evaluated by both the visual semiquantitative analysis and the quantitative time-intensity curve analysis. Serum hs-CRP levels were detected using the particle-enhanced immunoturbidimetric assay also before the operation. Additionally, the carotid plaque samples were subjected to histopathological examination postoperatively. The density of neovessels and the number of macrophages in the plaques were assessed by immunohistochemistry. The results showed that among the 115 patients, grade 0 plaque contrast enhancement was noted in 35 patients, grade 1 in 48 patients and grade 2 in 32 patients. The degree of plaque enhancement, the density of neovessels, the number of macrophages, and the hs-CRP levels were highest in the grade 2 patients. Correlation analysis showed that the enhancement degree of the carotid plaques was closely related to the immunohistochemical parameters of the plaques and the serum hs-CRP levels. It was suggested that the carotid plaque enhancement on CEUS can be used to evaluate the vulnerability of carotid plaques.
