In the last decade, the rise of two-dimensional (2D) materials has attracted a tremendous amount of interest for the entire field of photonics and opto-electronics. The mechanism of light-matter interaction in 2D ma...In the last decade, the rise of two-dimensional (2D) materials has attracted a tremendous amount of interest for the entire field of photonics and opto-electronics. The mechanism of light-matter interaction in 2D materials challenges the knowledge of materials physics, which drives the rapid development of materials synthesis and device applications. 2D materials coupled with plasmonic effects show impressive optical characteristics, involving efficient charge transfer, plas- monic hot electrons doping, enhanced light-emitting, and ultrasensitive photodetection. Here, we briefly review the recent remarkable progress of 2D materials, mainly on graphene and transition metal dichalcogenides, focusing on their tunable optical properties and improved opto-electronic devices with plasmonic effects. The mechanism of plasmon enhanced light-matter interaction in 2D materials is elaborated in detail, and the state-of-the-art of device applications is compre- hensively described. In the future, the field of 2D materials holds great promise as an important platform for materials science and opto-electronic engineering, enabling an emerging interdisciplinary research field spanning from clean energy to information technology.展开更多
Great experimental results and observations achieved by Astronomy in the last decades revealed new unexplainable phenomena. Astronomers have conclusive new evidence that a recently discovered “dark galaxy” is, in fa...Great experimental results and observations achieved by Astronomy in the last decades revealed new unexplainable phenomena. Astronomers have conclusive new evidence that a recently discovered “dark galaxy” is, in fact, an object the size of a galaxy, made entirely of dark matter. They found that the speed of the Earth’s rotation varies randomly each day. 115 years ago, the Tunguska Event was observed, and astronomers still do not have an explanation of It. Main results of the present article are: 1) Dark galaxies explained by the spinning of their Dark Matter Cores with the surface speed at equator less than the escape velocity. Their Rotational Fission is not happening. Extrasolar systems do not emerge;2) 21-cm Emission explained by the self-annihilation of Dark Matter particles XIONs (5.3 μeV);3) Sun-Earth-Moon Interaction explained by the influence of the Sun’s and the Moon’s magnetic field on the electrical currents of the charged Geomagma (the 660-km layer), and, as a result, the Earth’s daylength varies;4) Tunguska Event explained by a huge atmospheric explosion of the Superbolide, which was a stable Dark Matter Bubble before entering the Earth’s atmosphere.展开更多
Constructing multispecies submerged vegetation systems and maintaining stable seasonal succession is crucial for restoring shallow eutrophic lakes.However,little is known about the interactions between successional an...Constructing multispecies submerged vegetation systems and maintaining stable seasonal succession is crucial for restoring shallow eutrophic lakes.However,little is known about the interactions between successional and existing species of different growth forms,particularly under the low light and high nutrient conditions of eutrophic lakes.We measured the functional traits of mature Vallisneria natans(Lour.)Hara plants and Potamogeton crispus L.shoots in monoculture and mosaic patterns under different light and nutrient conditions.The effect of light on functional traits of the submerged macrophyte species was more significant than that of nutrients,but the reverse was true for P.crispus biomass allocation.Moreover,interspecific interactions affected only the submerged macrophytes under the low light condition and varied with species.Specifically,the interaction of P.crispus to V.natans was biased towards competition,while the interaction of V.natans to P.crispus was converted from facilitation to competition by eutrophication,particularly in the homogenous mosaic growth pattern.This study demonstrates that sufficient light is a prerequisite and patch planting is an effective means to form a multispecies submerged vegetation system.In addition,we emphasize that the coexistence of eutrophication and low light will likely result in a competition between submerged macrophytes thus simplifying the vegetation,even if their growth forms and growing seasons are different.These findings help explain the collapse of multispecies submerged vegetation and guide the restoration of aquatic plants in eutrophic lakes.展开更多
ELI-Beamlines(ELI-BL),one of the three pillars of the Extreme Light Infrastructure endeavour,will be in a unique position to perform research in high-energy-density-physics(HEDP),plasma physics and ultra-high intensit...ELI-Beamlines(ELI-BL),one of the three pillars of the Extreme Light Infrastructure endeavour,will be in a unique position to perform research in high-energy-density-physics(HEDP),plasma physics and ultra-high intensity(UHI)ð>10^(22) W=cm^(2)) lasereplasma interaction.Recently the need for HED laboratory physics was identified and the P3(plasma physics platform)installation under construction in ELI-BL will be an answer.The ELI-BL 10 PW laser makes possible fundamental research topics from high-field physics to new extreme states of matter such as radiation-dominated ones,high-pressure quantum ones,warm dense matter(WDM)and ultra-relativistic plasmas.HEDP is of fundamental importance for research in the field of laboratory astrophysics and inertial confinement fusion(ICF).Reaching such extreme states of matter now and in the future will depend on the use of plasma optics for amplifying and focusing laser pulses.This article will present the relevant technological infrastructure being built in ELI-BL for HEDP and UHI,and gives a brief overview of some research under way in the field of UHI,laboratory astrophysics,ICF,WDM,and plasma optics.展开更多
Using L-glutathione(GSH) as a capping agent,Zn Se/GSH quantum dots(QDs) were prepared under microwave irradiation and irradiated under dark, ultraviolet light and incandescent light, respectively. The properties and i...Using L-glutathione(GSH) as a capping agent,Zn Se/GSH quantum dots(QDs) were prepared under microwave irradiation and irradiated under dark, ultraviolet light and incandescent light, respectively. The properties and interaction of different lights irradiated ZnSe/GSH QDs and bovine serum albumin(BSA) were studied systematically. The fluorescence(FL) spectra results reveal that the quenching mechanism are all the static quenching in nature. The quenching constant(Ksv) and binding constant(K) value of different irradiated Zn Se/GSH QDs and BSA all increased with the change of light types from dark to incandescent light and UV light. The number of binding site(n) is close to 1 at different temperatures. The lighting types influence the enthalpy and entropy changes. The Fourier transform infrared(FTIR) spectra indicate that the light induced GSH ligand will facilitate photocatalytic oxidation on the surface of ZnSe/GSH QDs. The circular dichroism(CD)results show that the α-helicity content of BSA decreases from 60.34%, 59.31%, to 58.79% under UV lighting,incandescent lighting and dark conditions. The interaction results of different lights illuminated ZnSe/GSH QDs with BSA by CD spectra method matches well with that by FL and FTIR spectra. That is, the interaction of ZnSe/GSH QDs and BSA from strong to weak is UV light, incandescent light and dark in sequence.展开更多
The author of this paper once attempted to propose a unified framework for gauge fields based on the mathematical and physical picture of the principal fiber bundle: that is, to believe that our universe may have more...The author of this paper once attempted to propose a unified framework for gauge fields based on the mathematical and physical picture of the principal fiber bundle: that is, to believe that our universe may have more fundamental interactions than the four, and these fundamental gauge fields are only components on the bottom manifold (i.e. our universe) projected by a unified gauge potential of the principal fiber bundle manifold;these components can satisfy the transformation of gauge potential, or even be transformed from one basic interaction gauge potential to another basic interaction gauge potential, and can be summarized into a unified equation, namely the generalized gauge equation expression, corresponding to gauge transformation invariance;so the invariance of gauge transformation is a necessary condition for unified field theory, and the four (or more) fundamental interaction fields of the universe are unified in a unified gauge field defined by the connection on the principal fiber bundle. In this paper, the author continues to propose a model of large-scale (gravitational) fundamental interactions in the universe based on the mathematical and physical picture of the principal fiber bundle, attempting to explain that dark matter and dark energy are merely reflections of these gravitational fundamental interactions that deviate in intensity from the gravitational fundamental interactions of the solar system at galaxy scales or some cosmic scales which are much larger than the solar system. All these “gravitational” fundamental interactions originate from the unified gauge field of the universe, namely the connection or curvature on the principal fiber bundle. These interactions are their projected representations on the bottom manifold (i.e. our universe) by different cross-sections (gauge transformations). These projection representations of the universe certainly are described by the generalized gauge equation or curvature similarity equation, and under the guidance of curvature gauge transformation factors, oscillate and evolve between the curvatures 1→0→-1→0→1 of the universe.展开更多
Nanoscale light sources with high speed of electrical modulation and low energy consumption are key components for nanophotonics and optoelectronics.The record-high carrier mobility and ultrafast carrier dynamics of g...Nanoscale light sources with high speed of electrical modulation and low energy consumption are key components for nanophotonics and optoelectronics.The record-high carrier mobility and ultrafast carrier dynamics of graphene make it promising as an atomically thin light emitter which can be further integrated into arbitrary platforms by van der Waals forces.However,due to the zero bandgap,graphene is difficult to emit light through the interband recombination of carriers like conventional semiconductors.Here,we demonstrate ultrafast thermal light emitters based on suspended graphene/hexagonal boron nitride(Gr/hBN)heterostructures.Electrons in biased graphene are significantly heated up to 2800 K at modest electric fields,emitting bright photons from the near-infrared to the visible spectral range.By eliminating the heat dissipation channel of the substrate,the radiation efficiency of the suspended Gr/hBN device is about two orders of magnitude greater than that of graphene devices supported on SiO2or hBN.Wefurther demonstrate that hot electrons and low-energy acoustic phonons in graphene are weakly coupled to each other and are not in full thermal equilibrium.Direct cooling ofhigh-temperature hot electrons to low-temperature acoustic phonons is enabled by the significant near-field heat transfer at the highly localized Gr/hBN interface,resulting in ultrafast thermal emission with up to 1 GHz bandwidth under electrical excitation.It is found thatsuspending the Gr/hBN heterostructures on the SiO2trenches significantly modifies the light emission due to the formation of the optical cavity and showed a~440%enhancement inintensity at the peak wavelength of 940 nm compared to the black-body thermal radiation.The demonstration of electrically driven ultrafast light emission from suspended Gr/hBNheterostructures sheds the light on applications of graphene heterostructures in photonicintegrated circuits,such as broadband light sources and ultrafast thermo-optic phase modulators.展开更多
The pictures from the James Webb Space Telescope (JWST) suggest that massive galaxies were already at the beginning of the expansion of the Universe because there was too short time to create them. It is consistent wi...The pictures from the James Webb Space Telescope (JWST) suggest that massive galaxies were already at the beginning of the expansion of the Universe because there was too short time to create them. It is consistent with the new cosmology presented within the Scale-Symmetric Theory (SST). The phase transitions of the initial inflation field described in SST lead to the Protoworld—its core was built of dark matter (DM). We show that the DAMA/LIBRA annual-modulation amplitude forced by the change of the Earth’s velocity (i.e. baryonic-matter (BM) velocity) in relation to the spinning DM field in our Galaxy’s halo should be very low. We calculated that in the DM-BM weak interactions are created single and entangled spacetime condensates with a lowest mass/energy of 0.807 keV—as the Higgs boson they can decay to two photons, so we can indirectly detect DM. Our results are consistent with the averaged DAMA/LIBRA/COSINE-100 curve describing the dependence of the event rate on the photon energy in single-hit events. We calculated the mean dark-matter-halo (DMH) mass around quasars, we also described the origin of the plateaux in the rotation curves for the massive spiral galaxies, the role of DM-loops in magnetars, the origin of CMB, the AGN-jet and galactic-halo production, and properties of dark energy (DE).展开更多
Dynamic protein-protein interactions are essential for proper cell functioning.Homointeraction events—physical interactions between the same type of proteins—represent a pivotal subset of protein-protein interaction...Dynamic protein-protein interactions are essential for proper cell functioning.Homointeraction events—physical interactions between the same type of proteins—represent a pivotal subset of protein-protein interactions that are widely exploited in activating intracellular signaling pathways.Capacities of modulating protein-protein interactions with spatial and temporal resolution are greatly desired to decipher the dynamic nature of signal transduction mechanisms.The emerging optogenetic technology,based on genetically encoded light-sensitive proteins,provides promising opportunities to dissect the highly complex signaling networks with unmatched specificity and spatiotemporal precision.Here we review recent achievements in the development of optogenetic tools enabling light-inducible protein-protein homo-interactions and their applications in optical activation of signaling pathways.展开更多
It is common experience that our eyes do not perceive significant changes in color when we observe for long time an object continuously exposed to light. We always see plants to be green in summer until in autumn fact...It is common experience that our eyes do not perceive significant changes in color when we observe for long time an object continuously exposed to light. We always see plants to be green in summer until in autumn factors external to our vision, such as changes in the length of daylight and temperature, cause the break-down of chlorophyll and, in turn, spectacular changes in plant’s colors. Likewise, the photocurrent produced in solar panels or field effect transistors achieves a steady state magnitude shortly after the start of the illumination. The steady state photocurrent lasts until the illumination stops. Understanding the origin of the steady state response of a device or light harvesting (LH) system to illumination with electromagnetic (EM) waves motivates the research presented in this work. In our experiments, we used capacitors as LH systems and illuminated them with infrared (IR) light over an 80 hours time period. We investigated the interaction between light and matter by monitoring versus time the voltage output of the capacitors. By combining modeling and experimental observations, we concluded that the steady state voltage is established soon after the start of the illumination as the consequence of the law of conservation of energy. We also found that the magnitude of the voltage in the steady state depends on the power and period of the illuminating IR light, and on the capacitance of the capacitor. When light’s power undergoes fluctuations, also the voltage produced by the capacitor and the surface charge density on the capacitors do so. These findings suggest that the law of conservation of energy has a significant repercussion when light is absorbed by matter in the steady state, for example in the mechanism of vision in vertebrates. Likewise, these findings are true when light is emitted from matter, for example in the mechanism of formation of the Cosmic Microwave Background (CMB).展开更多
Although numerous studies about the nature and turnover of soil organic matter(SOM) in light and heavy fractions( LFOM and HFQM, respectively) have been made, little information is available in relation to the rel...Although numerous studies about the nature and turnover of soil organic matter(SOM) in light and heavy fractions( LFOM and HFQM, respectively) have been made, little information is available in relation to the relationship between LFQM and HFOM, and no attempts have been made to quantify a general relationship between LFQM and HFQM for agricultural soils under field condition. Qur hypothesis is there may be an inherent relationship between LFQM and HFQM for agricultural soils under certain unaltered management practices for a long period, to this end, we therefore studied typically soils taken from different parts in China by using a simple density fractionation procedure. The results indicated that LFQM was positively correlated with LFOM/HFOM ratio for three typical soils. This information will be of particular use not only in deepening our understanding of the dynamics of SQM fractions but also in evaluating the potential of agricultural soils to sequestrate C under different management practices in a long term.展开更多
The equations ofstate of the neutron star matter are calculated in the relativistic mean-field approximation witl different hyperon coupling constants. The properties of neutron stars are studied by solving the Oppenh...The equations ofstate of the neutron star matter are calculated in the relativistic mean-field approximation witl different hyperon coupling constants. The properties of neutron stars are studied by solving the OppenheimerVolkoff equation. It manifests the properties of neutron stars - change explicitly as different hyperon coupling constants are concerned.展开更多
The expression patterns of OsPILll, one of six putative phytochrome-interacting factors, were analyzed in different organs of transgenic tobacco (Nicotiana tabacum). The expression of OsPIL 11 was organ-specific and...The expression patterns of OsPILll, one of six putative phytochrome-interacting factors, were analyzed in different organs of transgenic tobacco (Nicotiana tabacum). The expression of OsPIL 11 was organ-specific and was regulated by leaf development, abscisic acid (ABA), jasmonic acid (JA) and salicylic acid (SA). To further explore the role of OsPIL 11 in plant light signal transduction, a plant expression vector of OsPILll was constructed and introduced into tobacco. When grown under continuous red light, OsPILll-overexpressed transgenic tobacco exhibited shorter hypocotyls and larger cotyledons and leaves compared to wild-type seedlings. When grown under continuous far-red light, however, transgenic and wild-type seedlings showed similar phenotypes. These results indicate that OsPILll is involved in red light induced de-etiolation, but not in far-red light induced de-etiolation in transgenic tobacco, which lays the foundation for dissecting the function of OsPIL11 in phytochrome-mediated light signal transduction in rice.展开更多
The main objective of our study has been to determine the role of deadwood in the shaping of the amount of soil organic matter fractions in mountain forest soils.For this purpose,a climosequence approach comprising no...The main objective of our study has been to determine the role of deadwood in the shaping of the amount of soil organic matter fractions in mountain forest soils.For this purpose,a climosequence approach comprising north(N)and south(S)exposure along the altitudinal gradient(600,800,1000 and 1200 m a.s.l.)was set up.By comparing the properties of decomposing deadwood and those of the soils located directly beneath the decaying wood we drew conclusions about the role of deadwood in the shaping of soil organic matter fractions and soil carbon storage in different climate conditions.The basic properties,enzymatic activity and fractions of soil organic matter(SOM)were determined in deadwood and affected directly by the components released from decaying wood.Heavily decomposed deadwood impacts soil organic matter stabilization more strongly than the less decayed deadwood and the light fraction of SOM is more sensitive to deadwood effects than the heavy fraction regardless of the location in the altitude gradient.Increase in SOM mineral-associated fraction C content is more pronounced in soils under the influence of deadwood located in lower locations of warmer exposure.Nutrients released from decaying wood stimulate the enzymatic activity of soils that are within the range of deadwood influence.展开更多
Hall effect of light is a result of symmetry breaking in spin and/or orbital angular momentum(OAM)possessing optical system and is caused by e.g.refractive index gradient/interface between media or focusing of a spati...Hall effect of light is a result of symmetry breaking in spin and/or orbital angular momentum(OAM)possessing optical system and is caused by e.g.refractive index gradient/interface between media or focusing of a spatially asymmetrical beam,similar to the electric field breaking the symmetry in spin Hall effect for electrons.The angular momentum(AM)conservation law in the ensuing asymmetric system dictates redistribution of spin and orbital angular momentum,and is manifested in spin-orbit,orbit-orbit,and orbit-spin conversions and reorganization,i.e.spin-orbit and orbit-orbit interaction.This AM restructuring in turn requires shifts of the barycenter of the electric field of light.In the present study we show,both analytically and by numerical simulation,how different electric field components are displaced upon tight focusing of an asymmetric light beam having OAM and spin.The relation between field components shifts and the AM components shifts/redistribution is presented too.Moreover,we experimentally demonstrate,for the first time,to the best of our knowledge,the spin-orbit Hall effect of light upon tight focusing in free space.This is achieved using azopolymers as a media detecting longitudinal or z component of the electrical field of light.These findings elucidate the Hall effect of light and may broaden the spectrum of its applications.展开更多
<strong>Context and Background</strong>: In this research, we investigate the interaction of X-rays with a capacitor by studying the voltage established in the capacitor during the illumination. <strong...<strong>Context and Background</strong>: In this research, we investigate the interaction of X-rays with a capacitor by studying the voltage established in the capacitor during the illumination. <strong>Motivation</strong>: We aim at verifying that the total energy conserved in the interaction is <span style="white-space:nowrap;"><i></i></span><i>Pτ, i.e.<span style="white-space:nowrap;"></span></i> the product of the average power <span style="white-space:nowrap;"><i></i></span><i>P<span style="white-space:nowrap;"></span></i> times the period τ of the X-rays. <strong>Hypothesis</strong>: Our investigation relies on the hypothesis that the voltage responsivity π<span style="white-space:nowrap;"><i></i></span><i><sub>V<span style="white-space:nowrap;"></span></sub></i> of the capacitor should be small, according to previous research. The parameter π<span style="white-space:nowrap;"><i></i></span><i><sub>V<span style="white-space:nowrap;"></span></sub></i> is the ratio between the voltage produced and the average power <span style="white-space:nowrap;"><i></i></span><i>P<span style="white-space:nowrap;"></span></i> of the X-rays, and measures the performance of the capacitor in response to the X-rays. <strong>Method</strong>: We measure the voltage produced by the capacitor in response to the X-rays, and then determine the average power <span style="white-space:nowrap;"><i></i></span><i>P<span style="white-space:nowrap;"></span></i> of the X-rays according to a procedure already assessed with infrared and visible light. <strong>Results</strong>: In our experiments, <span style="white-space:nowrap;"><i></i></span><i>P<span style="white-space:nowrap;"></span></i> turns out to be in the range between 10<sup><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">-</span>3 </sup>W to 10<sup>0</sup> W. Our procedure enables us to unveil the relationship between the average power P and the effective dose, an important operating parameter used to measure the delivery of X-rays in practical applications, such as standard X-ray medical imaging machines. <strong>Conclusions</strong>: We believe that our procedure paves the way for designing a possible X-ray power-meter, a tool presently missing in the market of X-ray characterization tools.展开更多
We study the ground state energy of an atom interacting with an oscillating optical field with electric dipole and quadrupole coupling.Under the rotating wave approximation,we derive the effective atomic Hamiltonians ...We study the ground state energy of an atom interacting with an oscillating optical field with electric dipole and quadrupole coupling.Under the rotating wave approximation,we derive the effective atomic Hamiltonians of the dipole/quadrupole coupling term within the perturbation theory up to the second order.Based on the effective Hamiltonians,we analyze the atomic ground-state energy corrections of these two processes in detail.As an application,we find that for alkali-like atoms,the energy correction from the quadrupole coupling is negligible small in comparison with that from the dipole coupling,which justifies the so-called dipole approximation used in literatures.Some special cases where the quadrupole interaction may have considerable energy corrections are also discussed.Our results would be beneficial for the study of atom–light interaction beyond dipole approximation.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2015CB932403)the National Natural Science Foundation of China(Grant Nos.61422501,11674012,11374023,and 61521004)+2 种基金Beijing Natural Science Foundation,China(Grant No.L140007)Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201420)National Program for Support of Top-notch Young Professionals,China
文摘In the last decade, the rise of two-dimensional (2D) materials has attracted a tremendous amount of interest for the entire field of photonics and opto-electronics. The mechanism of light-matter interaction in 2D materials challenges the knowledge of materials physics, which drives the rapid development of materials synthesis and device applications. 2D materials coupled with plasmonic effects show impressive optical characteristics, involving efficient charge transfer, plas- monic hot electrons doping, enhanced light-emitting, and ultrasensitive photodetection. Here, we briefly review the recent remarkable progress of 2D materials, mainly on graphene and transition metal dichalcogenides, focusing on their tunable optical properties and improved opto-electronic devices with plasmonic effects. The mechanism of plasmon enhanced light-matter interaction in 2D materials is elaborated in detail, and the state-of-the-art of device applications is compre- hensively described. In the future, the field of 2D materials holds great promise as an important platform for materials science and opto-electronic engineering, enabling an emerging interdisciplinary research field spanning from clean energy to information technology.
文摘Great experimental results and observations achieved by Astronomy in the last decades revealed new unexplainable phenomena. Astronomers have conclusive new evidence that a recently discovered “dark galaxy” is, in fact, an object the size of a galaxy, made entirely of dark matter. They found that the speed of the Earth’s rotation varies randomly each day. 115 years ago, the Tunguska Event was observed, and astronomers still do not have an explanation of It. Main results of the present article are: 1) Dark galaxies explained by the spinning of their Dark Matter Cores with the surface speed at equator less than the escape velocity. Their Rotational Fission is not happening. Extrasolar systems do not emerge;2) 21-cm Emission explained by the self-annihilation of Dark Matter particles XIONs (5.3 μeV);3) Sun-Earth-Moon Interaction explained by the influence of the Sun’s and the Moon’s magnetic field on the electrical currents of the charged Geomagma (the 660-km layer), and, as a result, the Earth’s daylength varies;4) Tunguska Event explained by a huge atmospheric explosion of the Superbolide, which was a stable Dark Matter Bubble before entering the Earth’s atmosphere.
基金Supported by the National Natural Science Foundation of China (Nos.U2240207,41971043,51809178)the Guangxi Key Research and Development Program of China (No.2018AB36010)。
文摘Constructing multispecies submerged vegetation systems and maintaining stable seasonal succession is crucial for restoring shallow eutrophic lakes.However,little is known about the interactions between successional and existing species of different growth forms,particularly under the low light and high nutrient conditions of eutrophic lakes.We measured the functional traits of mature Vallisneria natans(Lour.)Hara plants and Potamogeton crispus L.shoots in monoculture and mosaic patterns under different light and nutrient conditions.The effect of light on functional traits of the submerged macrophyte species was more significant than that of nutrients,but the reverse was true for P.crispus biomass allocation.Moreover,interspecific interactions affected only the submerged macrophytes under the low light condition and varied with species.Specifically,the interaction of P.crispus to V.natans was biased towards competition,while the interaction of V.natans to P.crispus was converted from facilitation to competition by eutrophication,particularly in the homogenous mosaic growth pattern.This study demonstrates that sufficient light is a prerequisite and patch planting is an effective means to form a multispecies submerged vegetation system.In addition,we emphasize that the coexistence of eutrophication and low light will likely result in a competition between submerged macrophytes thus simplifying the vegetation,even if their growth forms and growing seasons are different.These findings help explain the collapse of multispecies submerged vegetation and guide the restoration of aquatic plants in eutrophic lakes.
基金The authors acknowledge support from the project ELI:Extreme Light Infrastructure from European Regional Devel-opment(CZ.02.1.01/0.0/0.0/15-008/0000162)Also supported by the project High Field Initiative(CZ.02.1.01/0.0/0.0/15-003/0000449)from European Regional Development Fund.
文摘ELI-Beamlines(ELI-BL),one of the three pillars of the Extreme Light Infrastructure endeavour,will be in a unique position to perform research in high-energy-density-physics(HEDP),plasma physics and ultra-high intensity(UHI)ð>10^(22) W=cm^(2)) lasereplasma interaction.Recently the need for HED laboratory physics was identified and the P3(plasma physics platform)installation under construction in ELI-BL will be an answer.The ELI-BL 10 PW laser makes possible fundamental research topics from high-field physics to new extreme states of matter such as radiation-dominated ones,high-pressure quantum ones,warm dense matter(WDM)and ultra-relativistic plasmas.HEDP is of fundamental importance for research in the field of laboratory astrophysics and inertial confinement fusion(ICF).Reaching such extreme states of matter now and in the future will depend on the use of plasma optics for amplifying and focusing laser pulses.This article will present the relevant technological infrastructure being built in ELI-BL for HEDP and UHI,and gives a brief overview of some research under way in the field of UHI,laboratory astrophysics,ICF,WDM,and plasma optics.
基金Funded by the Natural Science Foundation of Hubei Province(2017CFB680)the Open Fund of the State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology(G201703)+2 种基金the Fund of Key Laboratory of Measurement and Control System for Offshore Environment,Fuqing Branch of Fujian Normal University(SI-KF1604)the Guiding Projects in Fujian Province(2018H0013)the Key Natural Fund Projects of Universities in Fujian Province(JZ160490)
文摘Using L-glutathione(GSH) as a capping agent,Zn Se/GSH quantum dots(QDs) were prepared under microwave irradiation and irradiated under dark, ultraviolet light and incandescent light, respectively. The properties and interaction of different lights irradiated ZnSe/GSH QDs and bovine serum albumin(BSA) were studied systematically. The fluorescence(FL) spectra results reveal that the quenching mechanism are all the static quenching in nature. The quenching constant(Ksv) and binding constant(K) value of different irradiated Zn Se/GSH QDs and BSA all increased with the change of light types from dark to incandescent light and UV light. The number of binding site(n) is close to 1 at different temperatures. The lighting types influence the enthalpy and entropy changes. The Fourier transform infrared(FTIR) spectra indicate that the light induced GSH ligand will facilitate photocatalytic oxidation on the surface of ZnSe/GSH QDs. The circular dichroism(CD)results show that the α-helicity content of BSA decreases from 60.34%, 59.31%, to 58.79% under UV lighting,incandescent lighting and dark conditions. The interaction results of different lights illuminated ZnSe/GSH QDs with BSA by CD spectra method matches well with that by FL and FTIR spectra. That is, the interaction of ZnSe/GSH QDs and BSA from strong to weak is UV light, incandescent light and dark in sequence.
文摘The author of this paper once attempted to propose a unified framework for gauge fields based on the mathematical and physical picture of the principal fiber bundle: that is, to believe that our universe may have more fundamental interactions than the four, and these fundamental gauge fields are only components on the bottom manifold (i.e. our universe) projected by a unified gauge potential of the principal fiber bundle manifold;these components can satisfy the transformation of gauge potential, or even be transformed from one basic interaction gauge potential to another basic interaction gauge potential, and can be summarized into a unified equation, namely the generalized gauge equation expression, corresponding to gauge transformation invariance;so the invariance of gauge transformation is a necessary condition for unified field theory, and the four (or more) fundamental interaction fields of the universe are unified in a unified gauge field defined by the connection on the principal fiber bundle. In this paper, the author continues to propose a model of large-scale (gravitational) fundamental interactions in the universe based on the mathematical and physical picture of the principal fiber bundle, attempting to explain that dark matter and dark energy are merely reflections of these gravitational fundamental interactions that deviate in intensity from the gravitational fundamental interactions of the solar system at galaxy scales or some cosmic scales which are much larger than the solar system. All these “gravitational” fundamental interactions originate from the unified gauge field of the universe, namely the connection or curvature on the principal fiber bundle. These interactions are their projected representations on the bottom manifold (i.e. our universe) by different cross-sections (gauge transformations). These projection representations of the universe certainly are described by the generalized gauge equation or curvature similarity equation, and under the guidance of curvature gauge transformation factors, oscillate and evolve between the curvatures 1→0→-1→0→1 of the universe.
基金supported by the National Natural Science Foundation of China(Nos.12174444 and 52202195)the Natural Science Foundation of Hunan Province(2020RC3032)。
文摘Nanoscale light sources with high speed of electrical modulation and low energy consumption are key components for nanophotonics and optoelectronics.The record-high carrier mobility and ultrafast carrier dynamics of graphene make it promising as an atomically thin light emitter which can be further integrated into arbitrary platforms by van der Waals forces.However,due to the zero bandgap,graphene is difficult to emit light through the interband recombination of carriers like conventional semiconductors.Here,we demonstrate ultrafast thermal light emitters based on suspended graphene/hexagonal boron nitride(Gr/hBN)heterostructures.Electrons in biased graphene are significantly heated up to 2800 K at modest electric fields,emitting bright photons from the near-infrared to the visible spectral range.By eliminating the heat dissipation channel of the substrate,the radiation efficiency of the suspended Gr/hBN device is about two orders of magnitude greater than that of graphene devices supported on SiO2or hBN.Wefurther demonstrate that hot electrons and low-energy acoustic phonons in graphene are weakly coupled to each other and are not in full thermal equilibrium.Direct cooling ofhigh-temperature hot electrons to low-temperature acoustic phonons is enabled by the significant near-field heat transfer at the highly localized Gr/hBN interface,resulting in ultrafast thermal emission with up to 1 GHz bandwidth under electrical excitation.It is found thatsuspending the Gr/hBN heterostructures on the SiO2trenches significantly modifies the light emission due to the formation of the optical cavity and showed a~440%enhancement inintensity at the peak wavelength of 940 nm compared to the black-body thermal radiation.The demonstration of electrically driven ultrafast light emission from suspended Gr/hBNheterostructures sheds the light on applications of graphene heterostructures in photonicintegrated circuits,such as broadband light sources and ultrafast thermo-optic phase modulators.
文摘The pictures from the James Webb Space Telescope (JWST) suggest that massive galaxies were already at the beginning of the expansion of the Universe because there was too short time to create them. It is consistent with the new cosmology presented within the Scale-Symmetric Theory (SST). The phase transitions of the initial inflation field described in SST lead to the Protoworld—its core was built of dark matter (DM). We show that the DAMA/LIBRA annual-modulation amplitude forced by the change of the Earth’s velocity (i.e. baryonic-matter (BM) velocity) in relation to the spinning DM field in our Galaxy’s halo should be very low. We calculated that in the DM-BM weak interactions are created single and entangled spacetime condensates with a lowest mass/energy of 0.807 keV—as the Higgs boson they can decay to two photons, so we can indirectly detect DM. Our results are consistent with the averaged DAMA/LIBRA/COSINE-100 curve describing the dependence of the event rate on the photon energy in single-hit events. We calculated the mean dark-matter-halo (DMH) mass around quasars, we also described the origin of the plateaux in the rotation curves for the massive spiral galaxies, the role of DM-loops in magnetars, the origin of CMB, the AGN-jet and galactic-halo production, and properties of dark energy (DE).
基金supported by a Shun Hing Institute of Advanced Engineering Grant(No.4720247)a General Research Fund/Early Career Scheme(No.24201919)from the Research Grants Council of Hong Kong Special Administrative Region(to LD)。
文摘Dynamic protein-protein interactions are essential for proper cell functioning.Homointeraction events—physical interactions between the same type of proteins—represent a pivotal subset of protein-protein interactions that are widely exploited in activating intracellular signaling pathways.Capacities of modulating protein-protein interactions with spatial and temporal resolution are greatly desired to decipher the dynamic nature of signal transduction mechanisms.The emerging optogenetic technology,based on genetically encoded light-sensitive proteins,provides promising opportunities to dissect the highly complex signaling networks with unmatched specificity and spatiotemporal precision.Here we review recent achievements in the development of optogenetic tools enabling light-inducible protein-protein homo-interactions and their applications in optical activation of signaling pathways.
文摘It is common experience that our eyes do not perceive significant changes in color when we observe for long time an object continuously exposed to light. We always see plants to be green in summer until in autumn factors external to our vision, such as changes in the length of daylight and temperature, cause the break-down of chlorophyll and, in turn, spectacular changes in plant’s colors. Likewise, the photocurrent produced in solar panels or field effect transistors achieves a steady state magnitude shortly after the start of the illumination. The steady state photocurrent lasts until the illumination stops. Understanding the origin of the steady state response of a device or light harvesting (LH) system to illumination with electromagnetic (EM) waves motivates the research presented in this work. In our experiments, we used capacitors as LH systems and illuminated them with infrared (IR) light over an 80 hours time period. We investigated the interaction between light and matter by monitoring versus time the voltage output of the capacitors. By combining modeling and experimental observations, we concluded that the steady state voltage is established soon after the start of the illumination as the consequence of the law of conservation of energy. We also found that the magnitude of the voltage in the steady state depends on the power and period of the illuminating IR light, and on the capacitance of the capacitor. When light’s power undergoes fluctuations, also the voltage produced by the capacitor and the surface charge density on the capacitors do so. These findings suggest that the law of conservation of energy has a significant repercussion when light is absorbed by matter in the steady state, for example in the mechanism of vision in vertebrates. Likewise, these findings are true when light is emitted from matter, for example in the mechanism of formation of the Cosmic Microwave Background (CMB).
文摘Although numerous studies about the nature and turnover of soil organic matter(SOM) in light and heavy fractions( LFOM and HFQM, respectively) have been made, little information is available in relation to the relationship between LFQM and HFOM, and no attempts have been made to quantify a general relationship between LFQM and HFQM for agricultural soils under field condition. Qur hypothesis is there may be an inherent relationship between LFQM and HFQM for agricultural soils under certain unaltered management practices for a long period, to this end, we therefore studied typically soils taken from different parts in China by using a simple density fractionation procedure. The results indicated that LFQM was positively correlated with LFOM/HFOM ratio for three typical soils. This information will be of particular use not only in deepening our understanding of the dynamics of SQM fractions but also in evaluating the potential of agricultural soils to sequestrate C under different management practices in a long term.
文摘The equations ofstate of the neutron star matter are calculated in the relativistic mean-field approximation witl different hyperon coupling constants. The properties of neutron stars are studied by solving the OppenheimerVolkoff equation. It manifests the properties of neutron stars - change explicitly as different hyperon coupling constants are concerned.
基金supported by grants from the Chinese National Natural Science Foundation (Grant No. 30971744)the Chinese Ministry of Agriculture(Grant No. 2009ZX08001-029B)the Shandong Natural Science Funds for Distinguished Young Scholar,China (Grant No. JQ200911)
文摘The expression patterns of OsPILll, one of six putative phytochrome-interacting factors, were analyzed in different organs of transgenic tobacco (Nicotiana tabacum). The expression of OsPIL 11 was organ-specific and was regulated by leaf development, abscisic acid (ABA), jasmonic acid (JA) and salicylic acid (SA). To further explore the role of OsPIL 11 in plant light signal transduction, a plant expression vector of OsPILll was constructed and introduced into tobacco. When grown under continuous red light, OsPILll-overexpressed transgenic tobacco exhibited shorter hypocotyls and larger cotyledons and leaves compared to wild-type seedlings. When grown under continuous far-red light, however, transgenic and wild-type seedlings showed similar phenotypes. These results indicate that OsPILll is involved in red light induced de-etiolation, but not in far-red light induced de-etiolation in transgenic tobacco, which lays the foundation for dissecting the function of OsPIL11 in phytochrome-mediated light signal transduction in rice.
基金financed by the National Science Centre,Poland:decision no.DEC 2020/39/B/NZ9/00372
文摘The main objective of our study has been to determine the role of deadwood in the shaping of the amount of soil organic matter fractions in mountain forest soils.For this purpose,a climosequence approach comprising north(N)and south(S)exposure along the altitudinal gradient(600,800,1000 and 1200 m a.s.l.)was set up.By comparing the properties of decomposing deadwood and those of the soils located directly beneath the decaying wood we drew conclusions about the role of deadwood in the shaping of soil organic matter fractions and soil carbon storage in different climate conditions.The basic properties,enzymatic activity and fractions of soil organic matter(SOM)were determined in deadwood and affected directly by the components released from decaying wood.Heavily decomposed deadwood impacts soil organic matter stabilization more strongly than the less decayed deadwood and the light fraction of SOM is more sensitive to deadwood effects than the heavy fraction regardless of the location in the altitude gradient.Increase in SOM mineral-associated fraction C content is more pronounced in soils under the influence of deadwood located in lower locations of warmer exposure.Nutrients released from decaying wood stimulate the enzymatic activity of soils that are within the range of deadwood influence.
基金supported by the Russian Science Foundation grant No.22-79-10007.
文摘Hall effect of light is a result of symmetry breaking in spin and/or orbital angular momentum(OAM)possessing optical system and is caused by e.g.refractive index gradient/interface between media or focusing of a spatially asymmetrical beam,similar to the electric field breaking the symmetry in spin Hall effect for electrons.The angular momentum(AM)conservation law in the ensuing asymmetric system dictates redistribution of spin and orbital angular momentum,and is manifested in spin-orbit,orbit-orbit,and orbit-spin conversions and reorganization,i.e.spin-orbit and orbit-orbit interaction.This AM restructuring in turn requires shifts of the barycenter of the electric field of light.In the present study we show,both analytically and by numerical simulation,how different electric field components are displaced upon tight focusing of an asymmetric light beam having OAM and spin.The relation between field components shifts and the AM components shifts/redistribution is presented too.Moreover,we experimentally demonstrate,for the first time,to the best of our knowledge,the spin-orbit Hall effect of light upon tight focusing in free space.This is achieved using azopolymers as a media detecting longitudinal or z component of the electrical field of light.These findings elucidate the Hall effect of light and may broaden the spectrum of its applications.
文摘<strong>Context and Background</strong>: In this research, we investigate the interaction of X-rays with a capacitor by studying the voltage established in the capacitor during the illumination. <strong>Motivation</strong>: We aim at verifying that the total energy conserved in the interaction is <span style="white-space:nowrap;"><i></i></span><i>Pτ, i.e.<span style="white-space:nowrap;"></span></i> the product of the average power <span style="white-space:nowrap;"><i></i></span><i>P<span style="white-space:nowrap;"></span></i> times the period τ of the X-rays. <strong>Hypothesis</strong>: Our investigation relies on the hypothesis that the voltage responsivity π<span style="white-space:nowrap;"><i></i></span><i><sub>V<span style="white-space:nowrap;"></span></sub></i> of the capacitor should be small, according to previous research. The parameter π<span style="white-space:nowrap;"><i></i></span><i><sub>V<span style="white-space:nowrap;"></span></sub></i> is the ratio between the voltage produced and the average power <span style="white-space:nowrap;"><i></i></span><i>P<span style="white-space:nowrap;"></span></i> of the X-rays, and measures the performance of the capacitor in response to the X-rays. <strong>Method</strong>: We measure the voltage produced by the capacitor in response to the X-rays, and then determine the average power <span style="white-space:nowrap;"><i></i></span><i>P<span style="white-space:nowrap;"></span></i> of the X-rays according to a procedure already assessed with infrared and visible light. <strong>Results</strong>: In our experiments, <span style="white-space:nowrap;"><i></i></span><i>P<span style="white-space:nowrap;"></span></i> turns out to be in the range between 10<sup><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">-</span>3 </sup>W to 10<sup>0</sup> W. Our procedure enables us to unveil the relationship between the average power P and the effective dose, an important operating parameter used to measure the delivery of X-rays in practical applications, such as standard X-ray medical imaging machines. <strong>Conclusions</strong>: We believe that our procedure paves the way for designing a possible X-ray power-meter, a tool presently missing in the market of X-ray characterization tools.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.21503138,11247324,61405003,11604225,11404225,and 11474205)the Fund from Beijing Education Committees,China(Grant No.KM201710028004)
文摘We study the ground state energy of an atom interacting with an oscillating optical field with electric dipole and quadrupole coupling.Under the rotating wave approximation,we derive the effective atomic Hamiltonians of the dipole/quadrupole coupling term within the perturbation theory up to the second order.Based on the effective Hamiltonians,we analyze the atomic ground-state energy corrections of these two processes in detail.As an application,we find that for alkali-like atoms,the energy correction from the quadrupole coupling is negligible small in comparison with that from the dipole coupling,which justifies the so-called dipole approximation used in literatures.Some special cases where the quadrupole interaction may have considerable energy corrections are also discussed.Our results would be beneficial for the study of atom–light interaction beyond dipole approximation.