Observing and timing a group of millisecond pulsars with high rotational stability enables the direct detection of gravitational waves(GWs).The GW signals can be identified from the spatial correlations encoded in the...Observing and timing a group of millisecond pulsars with high rotational stability enables the direct detection of gravitational waves(GWs).The GW signals can be identified from the spatial correlations encoded in the times-of-arrival of widely spaced pulsar-pairs.The Chinese Pulsar Timing Array(CPTA)is a collaboration aiming at the direct GW detection with observations carried out using Chinese radio telescopes.This short article serves as a“table of contents”for a forthcoming series of papers related to the CPTA Data Release 1(CPTA DR1)which uses observations from the Five-hundred-meter Aperture Spherical radio Telescope.Here,after summarizing the time span and accuracy of CPTA DR1,we report the key results of our statistical inference finding a correlated signal with amplitude logA_(c)=-14.4_(-2.8)^(+1.0)for spectral index in the range ofα∈[-1.8,1.5]assuming a GW background(GWB)induced quadrupolar correlation.The search for the Hellings–Downs(HD)correlation curve is also presented,where some evidence for the HD correlation has been found that a 4.6σstatistical significance is achieved using the discrete frequency method around the frequency of 14 n Hz.We expect that the future International Pulsar Timing Array data analysis and the next CPTA data release will be more sensitive to the n Hz GWB,which could verify the current results.展开更多
Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to ro...Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to robust control of the polarization direction of light.Nevertheless,polarization control has been studied largely independent of the phase or intensity of light.Here,we propose and experimentally validate a Malus-metasurface-assisted paradigm to enable simultaneous and independent control of the intensity and phase properties of light simply by polarization modulation.The orientation degeneracy of the classical Malus’s law implies a new degree of freedom and enables us to establish a one-to-many mapping strategy for designing anisotropic plasmonic nanostructures to engineer the Pancharatnam–Berry phase profile,while keeping the continuous intensity modulation unchanged.The proposed Malus metadevice can thus generate a near-field greyscale pattern,and project an independent far-field holographic image using an ultrathin and single-sized metasurface.This concept opens up distinct dimensions for conventional polarization optics,which allows one to merge the functionality of phase manipulation into an amplitudemanipulation-assisted optical component to form a multifunctional nano-optical device without increasing the complexity of the nanostructures.It can empower advanced applications in information multiplexing and encryption,anti-counterfeiting,dual-channel display for virtual/augmented reality,and many other related fields.展开更多
Marfan syndrome (MFS)(OMIM 154700) is a relatively common autosomal dominant genetic disease that causes skeletal, ocular, and cardiovascular defects and was first described by a French pediatrician in 1896 (Bitterman...Marfan syndrome (MFS)(OMIM 154700) is a relatively common autosomal dominant genetic disease that causes skeletal, ocular, and cardiovascular defects and was first described by a French pediatrician in 1896 (Bitterman and Sponseller, 2017). Its prevalence rate is 1/3000—1/5000, and more than 25% of cases are sporadic (Chiu et al., 2014). Studies have shown that about 90% of MFS is caused by variants in the fibrillin-1 gene (FBN1, OMIM 134797). FBN1, located on chromosome 15q21.1, encodes a macromolecular glycoprotein-fibrin 1, which aggregates to form microfibers in the extracellular matrix and distributes in various human connective tissues, such as periosteum, vessel wall, and crystal suspensor ligament. Variants in FNB1 have been reported in 65 exons, but the relationship between genotype and phenotype remains rather unclear (Sakai et al., 2016). Studies have also shown that patients with MFS and similar diseases may have variants in other related genes such as members of the transforming growth factor beta receptor (TGFBR) family (Mizuguchi et al., 2004;Sakai et al., 2006;Bolar et al., 2012;De Cario et al., 2018). For better prevention and treatment of MFS as well as for suspected MFS patients, there is a strong need for efficient genetic testing for early diagnosis and differential diagnoses of patients with related phenotypes (Aubart et al., 2018).展开更多
The unwanted zero-order light accompanied by the birth of diffractive optical elements and caused mainly by fabrication errors and wavelength variations is a key factor that deteriorates the performance of diffraction...The unwanted zero-order light accompanied by the birth of diffractive optical elements and caused mainly by fabrication errors and wavelength variations is a key factor that deteriorates the performance of diffraction-related optical devices such as holograms,gratings,beam shapers,beam splitters,optical diffusers,and diffractive microlenses.Here,inspired by the unique characteristic of nano-polarizer-based metasurfaces for both positive and negative amplitude modulation of incident light,we propose a general design paradigm to eliminate zero-order diffraction without burdening the metasurface design and fabrication.The experimentally demonstrated metahologram,which projects a holographic image with a wide angle of 70°×70°in the for field,presents a very low zero-order intensity(only 0.7%of the total energy of the reconstructed image).More importantly,the zero-orderfree meta-hologram has a large tolerance limit for wavelength variations(under a broadband illumination from520 to 660 nm),which brings important technical advances.The strategy proposed could significantly relieve the fabrication difficulty of metasurfaces and be viable for various diffractive-optics-related applications includingholography,laser beam shaping,optical data storage,vortex beam generation,and so on.展开更多
Digital light processing technique was applied to manufacture alumina ceramic parts with two types of lattice structure units, i.e. vertex interconnect structure and edge structure. The internal porosity of the unit i...Digital light processing technique was applied to manufacture alumina ceramic parts with two types of lattice structure units, i.e. vertex interconnect structure and edge structure. The internal porosity of the unit is 40%. The printed parts were sintered and the grain size is about 1.1 μm. The bending strength of the vertex interconnect structure is much larger than that of the edge structure. Materials genome initiative(MGI) aims to digital design and intelligent manufacture for advanced components. This research shows us an example to achieve this goal.展开更多
Achieving larger electromagnetic enhancement using a nanogap between neighboring metallic nanostructures has been long pursued for boosting light–matter interactions.However,the quantitative probing of this enhanceme...Achieving larger electromagnetic enhancement using a nanogap between neighboring metallic nanostructures has been long pursued for boosting light–matter interactions.However,the quantitative probing of this enhancement is hindered by the lack of a reliable experimental method for measuring the local fields within a subnanometer gap.Here,we use layered MoS2 as a two-dimensional atomic crystal probe in nanoparticle-on-mirror nanoantennas to measure the plasmonic enhancement in the gap by quantitative surface-enhanced Raman scattering.Our designs ensure that the probe filled in the gap has a well-defined lattice orientation and thickness,enabling independent extraction of the anisotropic field enhancements.We find that the field enhancement can be safely described by pure classical electromagnetic theory when the gap distance is no<1.24 nm.For a 0.62 nm gap,the probable emergence of quantum mechanical effects renders an average electric field enhancement of 114-fold,38.4%lower than classical predictions.展开更多
基金supported by the National SKA Program of China(2020SKA0120100)the National Natural Science Foundation of China(Nos.12041303 and 12250410246)+1 种基金the CAS-MPG LEGACY projectfunding from the Max-Planck Partner Group。
文摘Observing and timing a group of millisecond pulsars with high rotational stability enables the direct detection of gravitational waves(GWs).The GW signals can be identified from the spatial correlations encoded in the times-of-arrival of widely spaced pulsar-pairs.The Chinese Pulsar Timing Array(CPTA)is a collaboration aiming at the direct GW detection with observations carried out using Chinese radio telescopes.This short article serves as a“table of contents”for a forthcoming series of papers related to the CPTA Data Release 1(CPTA DR1)which uses observations from the Five-hundred-meter Aperture Spherical radio Telescope.Here,after summarizing the time span and accuracy of CPTA DR1,we report the key results of our statistical inference finding a correlated signal with amplitude logA_(c)=-14.4_(-2.8)^(+1.0)for spectral index in the range ofα∈[-1.8,1.5]assuming a GW background(GWB)induced quadrupolar correlation.The search for the Hellings–Downs(HD)correlation curve is also presented,where some evidence for the HD correlation has been found that a 4.6σstatistical significance is achieved using the discrete frequency method around the frequency of 14 n Hz.We expect that the future International Pulsar Timing Array data analysis and the next CPTA data release will be more sensitive to the n Hz GWB,which could verify the current results.
基金the support from the MOST 2017YFA0205800the funding provided by the National Natural Science Foundation of China(Nos.91950110,11774273,11904267,61805184,and 11674256)+2 种基金the financial support from the Postdoctoral Innovation Talent Support Program of China(BX20180221)the China Postdoctoral Science Foundation(2019M652688)the financial support from the National Research Foundation,Prime Minister’s Office,Singapore under its Competitive Research Program(CRP award NRF CRP15-2015-03).
文摘Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to robust control of the polarization direction of light.Nevertheless,polarization control has been studied largely independent of the phase or intensity of light.Here,we propose and experimentally validate a Malus-metasurface-assisted paradigm to enable simultaneous and independent control of the intensity and phase properties of light simply by polarization modulation.The orientation degeneracy of the classical Malus’s law implies a new degree of freedom and enables us to establish a one-to-many mapping strategy for designing anisotropic plasmonic nanostructures to engineer the Pancharatnam–Berry phase profile,while keeping the continuous intensity modulation unchanged.The proposed Malus metadevice can thus generate a near-field greyscale pattern,and project an independent far-field holographic image using an ultrathin and single-sized metasurface.This concept opens up distinct dimensions for conventional polarization optics,which allows one to merge the functionality of phase manipulation into an amplitudemanipulation-assisted optical component to form a multifunctional nano-optical device without increasing the complexity of the nanostructures.It can empower advanced applications in information multiplexing and encryption,anti-counterfeiting,dual-channel display for virtual/augmented reality,and many other related fields.
基金supported by the National Key R&D Program of China (2018YFC1002302, 2016YFC0900103)National Natural Science Foundation of China (81671458)+1 种基金Beijing Lab for Cardiovascular Precision Medicine (PXM2018_014226_000013)supported by the Reproduction Center Biobank at Peking University Third Hospital
文摘Marfan syndrome (MFS)(OMIM 154700) is a relatively common autosomal dominant genetic disease that causes skeletal, ocular, and cardiovascular defects and was first described by a French pediatrician in 1896 (Bitterman and Sponseller, 2017). Its prevalence rate is 1/3000—1/5000, and more than 25% of cases are sporadic (Chiu et al., 2014). Studies have shown that about 90% of MFS is caused by variants in the fibrillin-1 gene (FBN1, OMIM 134797). FBN1, located on chromosome 15q21.1, encodes a macromolecular glycoprotein-fibrin 1, which aggregates to form microfibers in the extracellular matrix and distributes in various human connective tissues, such as periosteum, vessel wall, and crystal suspensor ligament. Variants in FNB1 have been reported in 65 exons, but the relationship between genotype and phenotype remains rather unclear (Sakai et al., 2016). Studies have also shown that patients with MFS and similar diseases may have variants in other related genes such as members of the transforming growth factor beta receptor (TGFBR) family (Mizuguchi et al., 2004;Sakai et al., 2006;Bolar et al., 2012;De Cario et al., 2018). For better prevention and treatment of MFS as well as for suspected MFS patients, there is a strong need for efficient genetic testing for early diagnosis and differential diagnoses of patients with related phenotypes (Aubart et al., 2018).
基金National Key Research and Development Program of China(2017YFA0205800)National Natural Science Foundation of China(91950110,11774273,11904267,61805184,11674256)+2 种基金Outstanding Youth Funds of Hubei Province(2016CFA034)Postdoctoral Innovation Talent Support Program of China(BX20180221)China Postdoctoral Science Foundation(2019M652688)。
文摘The unwanted zero-order light accompanied by the birth of diffractive optical elements and caused mainly by fabrication errors and wavelength variations is a key factor that deteriorates the performance of diffraction-related optical devices such as holograms,gratings,beam shapers,beam splitters,optical diffusers,and diffractive microlenses.Here,inspired by the unique characteristic of nano-polarizer-based metasurfaces for both positive and negative amplitude modulation of incident light,we propose a general design paradigm to eliminate zero-order diffraction without burdening the metasurface design and fabrication.The experimentally demonstrated metahologram,which projects a holographic image with a wide angle of 70°×70°in the for field,presents a very low zero-order intensity(only 0.7%of the total energy of the reconstructed image).More importantly,the zero-orderfree meta-hologram has a large tolerance limit for wavelength variations(under a broadband illumination from520 to 660 nm),which brings important technical advances.The strategy proposed could significantly relieve the fabrication difficulty of metasurfaces and be viable for various diffractive-optics-related applications includingholography,laser beam shaping,optical data storage,vortex beam generation,and so on.
基金the National Key R&D Program of China (Grants Nos. 2017YFB0703200, 2016YFB0700500)the National Natural Science Foundation of China (Grants Nos.51372203, 51332004, 51571166, 51972268 and 51761135032)the Foreign Talents Introduction and Academic Exchange Program (Grant No. B08040) for their financial supports
文摘Digital light processing technique was applied to manufacture alumina ceramic parts with two types of lattice structure units, i.e. vertex interconnect structure and edge structure. The internal porosity of the unit is 40%. The printed parts were sintered and the grain size is about 1.1 μm. The bending strength of the vertex interconnect structure is much larger than that of the edge structure. Materials genome initiative(MGI) aims to digital design and intelligent manufacture for advanced components. This research shows us an example to achieve this goal.
基金supported by the National Key Basic Research Program(Grant No.2015CB932400)the National Key R&D Program of China(Grant Nos.2017YFA0303504 and 2017YFA0205800)+1 种基金the National Natural Science Foundation of China(Grant Nos.11304233,11674256,11674255,and 11404247)the China Postdoctoral Science Foundation(Grant No.2014T70727).
文摘Achieving larger electromagnetic enhancement using a nanogap between neighboring metallic nanostructures has been long pursued for boosting light–matter interactions.However,the quantitative probing of this enhancement is hindered by the lack of a reliable experimental method for measuring the local fields within a subnanometer gap.Here,we use layered MoS2 as a two-dimensional atomic crystal probe in nanoparticle-on-mirror nanoantennas to measure the plasmonic enhancement in the gap by quantitative surface-enhanced Raman scattering.Our designs ensure that the probe filled in the gap has a well-defined lattice orientation and thickness,enabling independent extraction of the anisotropic field enhancements.We find that the field enhancement can be safely described by pure classical electromagnetic theory when the gap distance is no<1.24 nm.For a 0.62 nm gap,the probable emergence of quantum mechanical effects renders an average electric field enhancement of 114-fold,38.4%lower than classical predictions.
