The development of polymeric optical materials with a higher refractive index,transparency in the visible spectrum region and easier processability is increasingly desirable for advanced optical applications such as m...The development of polymeric optical materials with a higher refractive index,transparency in the visible spectrum region and easier processability is increasingly desirable for advanced optical applications such as microlenses,image sensors,and organic light-emitting diodes.Most acrylates have a low refractive index(around 1.50)which does not meet the high perfo rmance requirements of advanced optical materials.In this research,three novel acrylates were synthesized via a facile one-step approach and used to fabricate optical transparent polymers.All of the polymers reveal good optical properties including high transparency(≥90%)in the visible spectrum region and high refractive index values(1.6363)at 550 nm.Moreover,nanostructures of these acrylate polymers with various feature sizes including nanogratings and photonic crystals were successfully fabricated using nanoimprint lithography.These results indicate that these acrylates can be used in a wide range of optical and optoelectronic devices where nanopatterned films with high refractive index and transparency are required.展开更多
In the light of current concerns related to induced seismicity associated with geological carbon sequestration(GCS),this paper summarizes lessons learned from recent modeling studies on fault activation,induced seismi...In the light of current concerns related to induced seismicity associated with geological carbon sequestration(GCS),this paper summarizes lessons learned from recent modeling studies on fault activation,induced seismicity,and potential for leakage associated with deep underground carbon dioxide(CO2) injection.Model simulations demonstrate that seismic events large enough to be felt by humans require brittle fault properties and continuous fault permeability allowing pressure to be distributed over a large fault patch to be ruptured at once.Heterogeneous fault properties,which are commonly encountered in faults intersecting multilayered shale/sandstone sequences,effectively reduce the likelihood of inducing felt seismicity and also effectively impede upward CO2leakage.A number of simulations show that even a sizable seismic event that could be felt may not be capable of opening a new flow path across the entire thickness of an overlying caprock and it is very unlikely to cross a system of multiple overlying caprock units.Site-specific model simulations of the In Salah CO2storage demonstration site showed that deep fractured zone responses and associated microseismicity occurred in the brittle fractured sandstone reservoir,but at a very substantial reservoir overpressure close to the magnitude of the least principal stress.We conclude by emphasizing the importance of site investigation to characterize rock properties and if at all possible to avoid brittle rock such as proximity of crystalline basement or sites in hard and brittle sedimentary sequences that are more prone to injection-induced seismicity and permanent damage.展开更多
In this paper, we present a linked multicontinuum and crack tensor approach for modeling of coupled geomechanics, fluid flow, and solute transport in fractured rock. We used the crack tensor approach to calculate effe...In this paper, we present a linked multicontinuum and crack tensor approach for modeling of coupled geomechanics, fluid flow, and solute transport in fractured rock. We used the crack tensor approach to calculate effective block-scale properties, including anisotropic permeability and elastic tensors, as well as multicontinuum properties relevant to fracture-matrix interactions and matrix diffusion. In the mod- eling, we considered stress dependent properties, through stress-induced changes in fracture apertures, to update permeability and elastic tensors. We evaluated the effectiveness and accuracy of our multicon- tinuum approach by comparing our modeling results with that of three independent discrete fracture network （DFN） models. In two of the three alternative DFN models, solute transport was simulated by particle tracking, an approach very different from the standard solute transport used in our multicon- tinuum modeling. We compared the results for flow and solute transport through a 20 m x 20 m model domain of fractured rock, including detailed comparison of total flow rate, its distribution, and solute breakthrough curves. In our modeling, we divided the 20 m ~ 20 m model domain into regular blocks, or continuum elements. We selected a model discretization of 40 x 40 elements （having a side length of 0.5 m） that resulted in a fluid-flow rate equivalent to that of the DFN models. Our simulation results were in reasonably good agreement with the alternative DFN models, for both advective dominated transport （under high hydraulic gradient） and matrix-diffusion retarded transport （under low hydraulic gradient）. However, we found pronounced numerical dispersion when using larger grid blocks, a problem that could be remediated by the use of a finer numerical grid resolution, while maintaining a larger grid for evalua- tion of equivalent properties, i.e. a property grid overlapping the numerical grid. Finally, we encountered some difficulties in using our approach when element sizes were so small that only one or a few fractures intersect an element-this is an area of possible improvement that will be pursued in future research.展开更多
Since 1978, the University of California San Francisco (UCSF) Ocular Tumor Program has been using particle therapy for treating ocular patients with malignant as well as benign eye disease. Helium ion beams were used ...Since 1978, the University of California San Francisco (UCSF) Ocular Tumor Program has been using particle therapy for treating ocular patients with malignant as well as benign eye disease. Helium ion beams were used initially and were produced by two synchrotron-based systems: first by the 184-inch synchro-cyclotron and later by the Bevalac, at the Lawrence Berkeley National Laboratory (LBNL). Since 1994, protons, produced by a cyclotron-based system at the Crocker Nuclear Laboratory (CNL) Eye Treatment Facility (ETF), have been used for this purpose. The CNL cyclotron produces a 67.5 MeV beam, allowing for a uniquely homogeneous beam for eye treatment, without degradation of the beam or manipulation of the beam line. This paper describes, in detail, the control system for beam delivery, as implemented for measuring and delivering the radiation to ocular tumors at CNL. The control system allows for optimal delivery and rapid termination of the irradiation after the desired dose is achieved. In addition, several safeguard systems are discussed, as these are essential for such a system in the event of failure of software, electronics, or other hardware. The QA analysis shows that the total range of the proton beam is 30.7 ± 1.0 mm in water at iso-center. The beam distal penumbra (80% - 20%) is 1.1 mm for a range-modulated beam at a collimator to iso-center distance of 50 mm. Daily QA checks confirm that the range and modulation is within 0.1 mm. The beam flatness and symmetry in a 25 mm diameter beam are ±1% - 2%. Variation in the daily dosimetry system, as compared to standard dosimetry, is within ±3.5%, with a mean variation of 0.72(±1.9)% and 0.85(±2.3)% for segmented transmission ionization chambers IC1 (upstream) and IC2 (downstream), respectively. From May 1994 to the end of 2015, UCSF has treated 1838 proton ocular patients at the Davis ETF. During this period, no treatments were missed due to any cyclotron or control system failures. The overall performance, maintenance, and quality assurance of the cyclotron and the ocular control system have been excellent.展开更多
As one of the main components of the injector II of China ADS LINAC project, an RFQ working at 162.5 MHzis used to accelerate proton beams of 15 mA from 30 keV to 2.1 MeV. The four vane RFQ has been designed incollabo...As one of the main components of the injector II of China ADS LINAC project, an RFQ working at 162.5 MHzis used to accelerate proton beams of 15 mA from 30 keV to 2.1 MeV. The four vane RFQ has been designed incollaboration with Lawrence Berkeley National Laboratory and built at the workshop of the Institute of ModernPhysics, Chinese Academy of Sciences (IMP, CAS).展开更多
The BABAR database,based upon the Objectivity OO database management system,has been in production since early 1999,It has met its initial design requirements which were to accommodate a 100Hz event rate from the expe...The BABAR database,based upon the Objectivity OO database management system,has been in production since early 1999,It has met its initial design requirements which were to accommodate a 100Hz event rate from the experiment at a scale of 200TB per year.However,with increased luminosity and changes in the physics requirements,these requirements have increased significantly for the current running period and will again increase in the future.New capabilities in the underlying ODBMS product,in particular those of multiple federation and read-only database support,have been incorporated into a new design that is backwards compatible with existing application code while offering scaling into the multi-petabyte size regime.Other optimizations,including the increased use of thghtly coupled CORBA servers and an improved awareness of space inefficiencies,are also playing a part in meeting the new scaling requirements.We discuss these optimizations and the prospects for further scaling enhancements to address the longer-term needs of the experiment.展开更多
Herein,we report the synthesis and structures of two novel mixed-metal clusters denoted as Th_(9)Ag_(6)and Th_(9)Ag_(12).Both clusters feature unprecedented Th_(9)cores.The cores are tricapped trigonal prism moieties ...Herein,we report the synthesis and structures of two novel mixed-metal clusters denoted as Th_(9)Ag_(6)and Th_(9)Ag_(12).Both clusters feature unprecedented Th_(9)cores.The cores are tricapped trigonal prism moieties that are novel among actinides.Attempted alternative synthesis routes indicate that the Th_(9)clusters are accessible only through slow introduction of Ag_(+)into a solution containing a Th6 cluster modified with 2-picolinic acid.Alternative rapid addition of Ag_(+)leads to dissociation of the Th6 cluster with formation of a high-purity(ThAg)_(∞)two-dimensional layered structure material.A mechanism for cluster dissociation and reassembly to yield Th_(9)from Th6 is proposed that is consistent with spectroscopic observations and computational results.Because of Ag⋯Ag andπ–πinteractions,the Th_(9)Ag_(12)cluster exhibits high stability in air,at elevated temperature,underγ-irradiation,and in common solvents.展开更多
Although solid-phase extraction is a useful approach for metal ion separation from aqueous solutions,existing sorbents suffer from low extraction effici-encies and/or instability when in contact with strong acidic med...Although solid-phase extraction is a useful approach for metal ion separation from aqueous solutions,existing sorbents suffer from low extraction effici-encies and/or instability when in contact with strong acidic media.We report here the first study on rational design and fabrication of phosphonate-decorated covalent organic frameworks,COF-IHEP1 and COF-IHEP2,for efficient and selective extraction of of uranium(VI)[U(VI)]and plutonium(IV)[Pu(IV)]from highly acidic solutions.展开更多
The combination of electrophysiology and optogenetics enables the exploration of how the brain operates down to a single neuron and its network activity.Neural probes are in vivo invasive devices that integrate sensor...The combination of electrophysiology and optogenetics enables the exploration of how the brain operates down to a single neuron and its network activity.Neural probes are in vivo invasive devices that integrate sensors and stimulation sites to record and manipulate neuronal activity with high spatiotemporal resolution.State-of-the-art probes are limited by tradeoffs involving their lateral dimension,number of sensors,and ability to access independent stimulation sites.Here,we realize a highly scalable probe that features three-dimensional integration of small-footprint arrays of sensors and nanophotonic circuits to scale the density of sensors per cross-section by one order of magnitude with respect to state-of-the-art devices.For the first time,we overcome the spatial limit of the nanophotonic circuit by coupling only one waveguide to numerous optical ring resonators as passive nanophotonic switches.With this strategy,we achieve accurate on-demand light localization while avoiding spatially demanding bundles of waveguides and demonstrate the feasibility with a proof-of-concept device and its scalability towards high-resolution and low-damage neural optoelectrodes.展开更多
The question of material stability is of fundamental importance to any analysis of system properties in condensed matter physics and materials science.The ability to evaluate chemical stability,i.e.,whether a stoichio...The question of material stability is of fundamental importance to any analysis of system properties in condensed matter physics and materials science.The ability to evaluate chemical stability,i.e.,whether a stoichiometry will persist in some chemical environment,and structure selection,i.e.what crystal structure a stoichiometry will adopt,is critical to the prediction of materials synthesis,reactivity and properties.Here,we demonstrate that density functional theory,with the recently developed strongly constrained and appropriately normed(SCAN)functional,has advanced to a point where both facets of the stability problem can be reliably and efficiently predicted for main group compounds,while transition metal compounds are improved but remain a challenge.SCAN therefore offers a robust model for a significant portion of the periodic table,presenting an opportunity for the development of novel materials and the study of fine phase transformations even in largely unexplored systems with little to no experimental data.展开更多
The symmetries C （particle-antiparticle interchange） and P （space inversion） hold for strong and electromagnetic interactions. After the discovery of large C and P violation in the weak interactions, it appeared t...The symmetries C （particle-antiparticle interchange） and P （space inversion） hold for strong and electromagnetic interactions. After the discovery of large C and P violation in the weak interactions, it appeared that the product CP was a good symmetry. In 1964 CP violation was observed in K^0 decays at a level given by the parameter e ≈ 2.3 ×10^-3.展开更多
To investigate the feasibility of using a form cutter to machine the Radial Matcher Section （RMS） of tile Radio Frequency Quadrupole （RFQ） for the Accelerator Driven System （ADS） project at Institute of Modern P...To investigate the feasibility of using a form cutter to machine the Radial Matcher Section （RMS） of tile Radio Frequency Quadrupole （RFQ） for the Accelerator Driven System （ADS） project at Institute of Modern Physics, Chinese Academy of Sciences （IMP, CAS）, the influence of RMS end shape on the RFQ cavity frequency is studied. The results indicate that using a form cutter to machine the RMS of an RFQ will indeed influence the cavity frequency. The RMS end shape will give more influence to a shorter RFQ cavity. For the 4.2 m ADS RFQ, the influence is negligible, which means that a form cutter can be used to machine the RMS.展开更多
The Monte Carlo particle numbering scheme presented here is intended to facilitate interfacing between event generators, detector simulators, and analysis packages used in particle physics. The numbering scheme was in...The Monte Carlo particle numbering scheme presented here is intended to facilitate interfacing between event generators, detector simulators, and analysis packages used in particle physics. The numbering scheme was introduced in 1988 [1] and a revised version [2,3] was adopted in 1998 in order to allow systematic inclusion of quark model states which are as yet undiscovered and hypothetical particles such as SUSY particles. The numbering scheme is used in several event generators, e.g. HERWIG, PYTHIA, and SHERPA, and interfaces, e.g. /HEPEVT/and HepMC.展开更多
This note tells （1） how SU（n） particle multiplets are identified or labeled, （2） how to find the number of particles in a multiplet from its label, （3） how to draw the Young diagram for a multiplet, and （4） ...This note tells （1） how SU（n） particle multiplets are identified or labeled, （2） how to find the number of particles in a multiplet from its label, （3） how to draw the Young diagram for a multiplet, and （4） how to use Young diagrams to determine the overall multiplet structure of a composite system, such as a 3-quark or a meson-baryon system, In much of the literature, the word ＂representation＂ is used where we use ＂multiplet,＂ and ＂tableau＂ is used where we use ＂diagram.＂展开更多
The most commonly used SU（3） isoscalar factors, corresponding to the singlet, octet, and decuplet content of 8 × 8 and 10 × 8, are shown at the right. The notation uses particle names to identify the coeff...The most commonly used SU（3） isoscalar factors, corresponding to the singlet, octet, and decuplet content of 8 × 8 and 10 × 8, are shown at the right. The notation uses particle names to identify the coefficients, so that the pattern of relative couplings may be seen at a glance. We illustrate the use of the coefficients below. See J.J de Swart, Rev. Mod. Phys. 35, 916 （1963） for detailed explanations and phase conventions.展开更多
基金supported by the Molecular Foundry,Lawrence Berkeley National Laboratory,which is supported by the Office of Science and Office of Basic Energy Sciences of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231supported by National Natural Science Foundation of China (No.51573011)+2 种基金Natural Foundation of Jiangsu Province (No. BK20150272)Beijing Laboratory of Biomedical Materialsthe scholarship support from the program of the China Scholarship Council (No.201706880022) for study at Lawrence Berkeley National Laboratory
文摘The development of polymeric optical materials with a higher refractive index,transparency in the visible spectrum region and easier processability is increasingly desirable for advanced optical applications such as microlenses,image sensors,and organic light-emitting diodes.Most acrylates have a low refractive index(around 1.50)which does not meet the high perfo rmance requirements of advanced optical materials.In this research,three novel acrylates were synthesized via a facile one-step approach and used to fabricate optical transparent polymers.All of the polymers reveal good optical properties including high transparency(≥90%)in the visible spectrum region and high refractive index values(1.6363)at 550 nm.Moreover,nanostructures of these acrylate polymers with various feature sizes including nanogratings and photonic crystals were successfully fabricated using nanoimprint lithography.These results indicate that these acrylates can be used in a wide range of optical and optoelectronic devices where nanopatterned films with high refractive index and transparency are required.
基金funded by the Assistant Secretary for Fossil Energy,National Energy Technology Laboratory,National Risk Assessment Partnership of the U.S. Department of Energy under Contract No.DEAC02-05CH11231a Swiss National Science Foundation(SNSF) Ambizione Energy grant(PZENP2_160555)
文摘In the light of current concerns related to induced seismicity associated with geological carbon sequestration(GCS),this paper summarizes lessons learned from recent modeling studies on fault activation,induced seismicity,and potential for leakage associated with deep underground carbon dioxide(CO2) injection.Model simulations demonstrate that seismic events large enough to be felt by humans require brittle fault properties and continuous fault permeability allowing pressure to be distributed over a large fault patch to be ruptured at once.Heterogeneous fault properties,which are commonly encountered in faults intersecting multilayered shale/sandstone sequences,effectively reduce the likelihood of inducing felt seismicity and also effectively impede upward CO2leakage.A number of simulations show that even a sizable seismic event that could be felt may not be capable of opening a new flow path across the entire thickness of an overlying caprock and it is very unlikely to cross a system of multiple overlying caprock units.Site-specific model simulations of the In Salah CO2storage demonstration site showed that deep fractured zone responses and associated microseismicity occurred in the brittle fractured sandstone reservoir,but at a very substantial reservoir overpressure close to the magnitude of the least principal stress.We conclude by emphasizing the importance of site investigation to characterize rock properties and if at all possible to avoid brittle rock such as proximity of crystalline basement or sites in hard and brittle sedimentary sequences that are more prone to injection-induced seismicity and permanent damage.
基金conducted within the context of the international DECOVALEX-2011 ProjectFinancial support for Berkeley Laboratory authors was provided by the UK Nuclear Decommissioning Authority (NDA) to the Lawrence Berke-ley National Laboratory through the National Energy Technology Laboratory, under the U.S. Department of Energy Contract No. DE-AC02-05CH11231funded by the UK Engineering and Physical Sciences Research Council (EPSRC),the UK Nuclear Decommissioning Authority (NDA), and Serco, through CASE studentship award 08002638
文摘In this paper, we present a linked multicontinuum and crack tensor approach for modeling of coupled geomechanics, fluid flow, and solute transport in fractured rock. We used the crack tensor approach to calculate effective block-scale properties, including anisotropic permeability and elastic tensors, as well as multicontinuum properties relevant to fracture-matrix interactions and matrix diffusion. In the mod- eling, we considered stress dependent properties, through stress-induced changes in fracture apertures, to update permeability and elastic tensors. We evaluated the effectiveness and accuracy of our multicon- tinuum approach by comparing our modeling results with that of three independent discrete fracture network （DFN） models. In two of the three alternative DFN models, solute transport was simulated by particle tracking, an approach very different from the standard solute transport used in our multicon- tinuum modeling. We compared the results for flow and solute transport through a 20 m x 20 m model domain of fractured rock, including detailed comparison of total flow rate, its distribution, and solute breakthrough curves. In our modeling, we divided the 20 m ~ 20 m model domain into regular blocks, or continuum elements. We selected a model discretization of 40 x 40 elements （having a side length of 0.5 m） that resulted in a fluid-flow rate equivalent to that of the DFN models. Our simulation results were in reasonably good agreement with the alternative DFN models, for both advective dominated transport （under high hydraulic gradient） and matrix-diffusion retarded transport （under low hydraulic gradient）. However, we found pronounced numerical dispersion when using larger grid blocks, a problem that could be remediated by the use of a finer numerical grid resolution, while maintaining a larger grid for evalua- tion of equivalent properties, i.e. a property grid overlapping the numerical grid. Finally, we encountered some difficulties in using our approach when element sizes were so small that only one or a few fractures intersect an element-this is an area of possible improvement that will be pursued in future research.
文摘Since 1978, the University of California San Francisco (UCSF) Ocular Tumor Program has been using particle therapy for treating ocular patients with malignant as well as benign eye disease. Helium ion beams were used initially and were produced by two synchrotron-based systems: first by the 184-inch synchro-cyclotron and later by the Bevalac, at the Lawrence Berkeley National Laboratory (LBNL). Since 1994, protons, produced by a cyclotron-based system at the Crocker Nuclear Laboratory (CNL) Eye Treatment Facility (ETF), have been used for this purpose. The CNL cyclotron produces a 67.5 MeV beam, allowing for a uniquely homogeneous beam for eye treatment, without degradation of the beam or manipulation of the beam line. This paper describes, in detail, the control system for beam delivery, as implemented for measuring and delivering the radiation to ocular tumors at CNL. The control system allows for optimal delivery and rapid termination of the irradiation after the desired dose is achieved. In addition, several safeguard systems are discussed, as these are essential for such a system in the event of failure of software, electronics, or other hardware. The QA analysis shows that the total range of the proton beam is 30.7 ± 1.0 mm in water at iso-center. The beam distal penumbra (80% - 20%) is 1.1 mm for a range-modulated beam at a collimator to iso-center distance of 50 mm. Daily QA checks confirm that the range and modulation is within 0.1 mm. The beam flatness and symmetry in a 25 mm diameter beam are ±1% - 2%. Variation in the daily dosimetry system, as compared to standard dosimetry, is within ±3.5%, with a mean variation of 0.72(±1.9)% and 0.85(±2.3)% for segmented transmission ionization chambers IC1 (upstream) and IC2 (downstream), respectively. From May 1994 to the end of 2015, UCSF has treated 1838 proton ocular patients at the Davis ETF. During this period, no treatments were missed due to any cyclotron or control system failures. The overall performance, maintenance, and quality assurance of the cyclotron and the ocular control system have been excellent.
文摘As one of the main components of the injector II of China ADS LINAC project, an RFQ working at 162.5 MHzis used to accelerate proton beams of 15 mA from 30 keV to 2.1 MeV. The four vane RFQ has been designed incollaboration with Lawrence Berkeley National Laboratory and built at the workshop of the Institute of ModernPhysics, Chinese Academy of Sciences (IMP, CAS).
文摘The BABAR database,based upon the Objectivity OO database management system,has been in production since early 1999,It has met its initial design requirements which were to accommodate a 100Hz event rate from the experiment at a scale of 200TB per year.However,with increased luminosity and changes in the physics requirements,these requirements have increased significantly for the current running period and will again increase in the future.New capabilities in the underlying ODBMS product,in particular those of multiple federation and read-only database support,have been incorporated into a new design that is backwards compatible with existing application code while offering scaling into the multi-petabyte size regime.Other optimizations,including the increased use of thghtly coupled CORBA servers and an improved awareness of space inefficiencies,are also playing a part in meeting the new scaling requirements.We discuss these optimizations and the prospects for further scaling enhancements to address the longer-term needs of the experiment.
基金the National Science Fund for Distinguished Young Scholars(grant no.21925603)support of the National Natural Science Foundation of China(grant nos.22076187,11975152,11875057).The work of J.K.G.was supported by the U.S.Departme。
文摘Herein,we report the synthesis and structures of two novel mixed-metal clusters denoted as Th_(9)Ag_(6)and Th_(9)Ag_(12).Both clusters feature unprecedented Th_(9)cores.The cores are tricapped trigonal prism moieties that are novel among actinides.Attempted alternative synthesis routes indicate that the Th_(9)clusters are accessible only through slow introduction of Ag_(+)into a solution containing a Th6 cluster modified with 2-picolinic acid.Alternative rapid addition of Ag_(+)leads to dissociation of the Th6 cluster with formation of a high-purity(ThAg)_(∞)two-dimensional layered structure material.A mechanism for cluster dissociation and reassembly to yield Th_(9)from Th6 is proposed that is consistent with spectroscopic observations and computational results.Because of Ag⋯Ag andπ–πinteractions,the Th_(9)Ag_(12)cluster exhibits high stability in air,at elevated temperature,underγ-irradiation,and in common solvents.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.21577144,21777161,11575212,and 21806167)the Science Challenge Project(TZ2016004)the Youth Innovation Promotion As-sociation of CAS(2017020).
文摘Although solid-phase extraction is a useful approach for metal ion separation from aqueous solutions,existing sorbents suffer from low extraction effici-encies and/or instability when in contact with strong acidic media.We report here the first study on rational design and fabrication of phosphonate-decorated covalent organic frameworks,COF-IHEP1 and COF-IHEP2,for efficient and selective extraction of of uranium(VI)[U(VI)]and plutonium(IV)[Pu(IV)]from highly acidic solutions.
文摘The combination of electrophysiology and optogenetics enables the exploration of how the brain operates down to a single neuron and its network activity.Neural probes are in vivo invasive devices that integrate sensors and stimulation sites to record and manipulate neuronal activity with high spatiotemporal resolution.State-of-the-art probes are limited by tradeoffs involving their lateral dimension,number of sensors,and ability to access independent stimulation sites.Here,we realize a highly scalable probe that features three-dimensional integration of small-footprint arrays of sensors and nanophotonic circuits to scale the density of sensors per cross-section by one order of magnitude with respect to state-of-the-art devices.For the first time,we overcome the spatial limit of the nanophotonic circuit by coupling only one waveguide to numerous optical ring resonators as passive nanophotonic switches.With this strategy,we achieve accurate on-demand light localization while avoiding spatially demanding bundles of waveguides and demonstrate the feasibility with a proof-of-concept device and its scalability towards high-resolution and low-damage neural optoelectrodes.
基金Y.Z.,H.P.,J.P.P.and J.S.acknowledge the support from the Center for the Computational Design of Functional Layered Materials,an Energy Frontier Research Center funded by the US Department of Energy(DOE),Office of Science,Basic Energy Sciences(BES),under award No.DE-SC0012575.
文摘The question of material stability is of fundamental importance to any analysis of system properties in condensed matter physics and materials science.The ability to evaluate chemical stability,i.e.,whether a stoichiometry will persist in some chemical environment,and structure selection,i.e.what crystal structure a stoichiometry will adopt,is critical to the prediction of materials synthesis,reactivity and properties.Here,we demonstrate that density functional theory,with the recently developed strongly constrained and appropriately normed(SCAN)functional,has advanced to a point where both facets of the stability problem can be reliably and efficiently predicted for main group compounds,while transition metal compounds are improved but remain a challenge.SCAN therefore offers a robust model for a significant portion of the periodic table,presenting an opportunity for the development of novel materials and the study of fine phase transformations even in largely unexplored systems with little to no experimental data.
文摘The symmetries C （particle-antiparticle interchange） and P （space inversion） hold for strong and electromagnetic interactions. After the discovery of large C and P violation in the weak interactions, it appeared that the product CP was a good symmetry. In 1964 CP violation was observed in K^0 decays at a level given by the parameter e ≈ 2.3 ×10^-3.
基金Supported by"Strategic Priority Research Program"of the Chinese Academy of Sciences(XDA03020500)NSFC(110790001)
文摘To investigate the feasibility of using a form cutter to machine the Radial Matcher Section （RMS） of tile Radio Frequency Quadrupole （RFQ） for the Accelerator Driven System （ADS） project at Institute of Modern Physics, Chinese Academy of Sciences （IMP, CAS）, the influence of RMS end shape on the RFQ cavity frequency is studied. The results indicate that using a form cutter to machine the RMS of an RFQ will indeed influence the cavity frequency. The RMS end shape will give more influence to a shorter RFQ cavity. For the 4.2 m ADS RFQ, the influence is negligible, which means that a form cutter can be used to machine the RMS.
文摘The Monte Carlo particle numbering scheme presented here is intended to facilitate interfacing between event generators, detector simulators, and analysis packages used in particle physics. The numbering scheme was introduced in 1988 [1] and a revised version [2,3] was adopted in 1998 in order to allow systematic inclusion of quark model states which are as yet undiscovered and hypothetical particles such as SUSY particles. The numbering scheme is used in several event generators, e.g. HERWIG, PYTHIA, and SHERPA, and interfaces, e.g. /HEPEVT/and HepMC.
文摘This note tells （1） how SU（n） particle multiplets are identified or labeled, （2） how to find the number of particles in a multiplet from its label, （3） how to draw the Young diagram for a multiplet, and （4） how to use Young diagrams to determine the overall multiplet structure of a composite system, such as a 3-quark or a meson-baryon system, In much of the literature, the word ＂representation＂ is used where we use ＂multiplet,＂ and ＂tableau＂ is used where we use ＂diagram.＂
文摘The most commonly used SU（3） isoscalar factors, corresponding to the singlet, octet, and decuplet content of 8 × 8 and 10 × 8, are shown at the right. The notation uses particle names to identify the coefficients, so that the pattern of relative couplings may be seen at a glance. We illustrate the use of the coefficients below. See J.J de Swart, Rev. Mod. Phys. 35, 916 （1963） for detailed explanations and phase conventions.
