As an advanced 4^(th) generation synchrotron radiation facility,the Shenzhen Innovation Light-source Facility(SILF)storage ring is based on multi-bend achromat(MBA)lattices,enabling one to two orders of magnitude redu...As an advanced 4^(th) generation synchrotron radiation facility,the Shenzhen Innovation Light-source Facility(SILF)storage ring is based on multi-bend achromat(MBA)lattices,enabling one to two orders of magnitude reduction in beam emittance compared to the 3^(rd) generation storage ring.This significantly enhance the radiation brightness and coherence.The multipole magnets of many types for SILF storage ring are under preliminary design,which require high integral field homogeneity.As a result,a dedicated pole tip optimization procedure with high efficiency is developed for quadrupole and sextupole magnets with Opera-2D^(■)python script.The procedure considers also the 3D field effect which makes the optimization more straightforward.In this paper,the design of the quadrupole and sextupole magnets for SILF storage ring is first presented,followed by a detailed description of the implemented pole shape optimization method.展开更多
The partitioning of membrane proteins into lipid domains in cellular membranes is closely associated with the realization of the protein functions and it is influenced by various factors such as the post-translational...The partitioning of membrane proteins into lipid domains in cellular membranes is closely associated with the realization of the protein functions and it is influenced by various factors such as the post-translational modification of palmitoylation.However,the molecular mechanism of the effect of palmitoylation on membrane protein partitioning into the lipid domains remains elusive.In this work,taking human peripheral myelin protein 22(PMP22)as an example,we employ coarse-grained molecular dynamics simulations to investigate the partitioning of both the natural PMP22 and the palmitoylated PMP22(pal-PMP22)into the lipid domains of model myelin membranes.The results indicate that palmitoylation drives PMP22 to localize at the boundary of the liquid-ordered(Lo)and liquid-disordered(Ld)domains and increases the possibility of PMP22 partitioning into the Lo domains by changing the hydrophobic length of the proteins and perturbing the ordered packing of tails of the saturated lipids in the Lo domains.This work offers some novel insights into the role of palmitoylation in modulating the function of membrane proteins in cellular membranes.展开更多
In this study we theoretically demonstrate ultrahigh-resolution two-dimensional atomic localization within a three-levelλ-type atomic medium via superposition of asymmetric and symmetric standing wave fields.Our anal...In this study we theoretically demonstrate ultrahigh-resolution two-dimensional atomic localization within a three-levelλ-type atomic medium via superposition of asymmetric and symmetric standing wave fields.Our analysis provides an understanding of the precise spatial localization of atomic positions at the atomic level,utilizing advanced theoretical approaches and principles of quantum mechanics.The dynamical behavior of a three-level atomic system is thoroughly analyzed using the density matrix formalism within the realm of quantum mechanics.A theoretical approach is constructed to describe the interaction between the system and external fields,specifically a control field and a probe field.The absorption spectrum of the probe field is thoroughly examined to clarify the spatial localization of the atom within the proposed configuration.A theoretical investigation found that symmetric and asymmetric superposition phenomena significantly influence the localized peaks within a two-dimensional spatial domain.Specifically,the emergence of one and two sharp localized peaks was observed within a one-wavelength domain.We observed notable influences of the intensity of the control field,probe field detuning and decay rates on atomic localization.Ultimately,we have achieved an unprecedented level of ultrahigh resolution and precision in localizing an atom within an area smaller thanλ/35×λ/35.These findings hold promise for potential applications in fields such as Bose-Einstein condensation,nanolithography,laser cooling,trapping of neutral atoms and the measurement of center-of-mass wave functions.展开更多
The development of an analytical method for determining the properties of quantum dots(QDs)is crucial for improving the optical performance of QD-based displays.Therefore,synchrotron-based X-ray photoelectron spectros...The development of an analytical method for determining the properties of quantum dots(QDs)is crucial for improving the optical performance of QD-based displays.Therefore,synchrotron-based X-ray photoelectron spectroscopy(XPS)is designed here to accurately characterize the chemical and structural differences between different QDs.This method enables the determination of the reason for the minimal differences between the optical properties of different QDs depending on the synthesis process,which is difficult to determine using conventional methods alone.Combined with model simulations,the XPS spectra obtained at different photon energies reveal the internal structures and chemical-state distributions of the QDs.In particular,the QD synthesized under optimal conditions demonstrates a relatively lower degree of oxidation of the core and more uniformly stacked ZnSe/ZnS shell layers.The internal structures and chemical-state distributions of QDs are closely related to their optical properties.Finally,the synchrotron-based XPS proposed here can be applied to compare nearly equivalent QDs with slightly different optical properties.展开更多
Anionic redox reaction(ARR)can provide extra capacity beyond transition metal(TM)redox in lithium-rich TM oxide cathodes.Practical ARR application is much hindered by the structure instability,particularly at the surf...Anionic redox reaction(ARR)can provide extra capacity beyond transition metal(TM)redox in lithium-rich TM oxide cathodes.Practical ARR application is much hindered by the structure instability,particularly at the surface.Oxygen release has been widely accepted as the ringleader of surficial structure instability.However,the role of TM in surface stability has been much overlooked,not to mention its interplay with oxygen release.Herein,TM dissolution and oxygen release are comparatively investigated in Li_(1.2)Ni_(0.2)Mn_(0.6)O_(2).Ni is verified to detach from the lattice counter-intuitively despite the overwhelming stoichiometry of Mn,facilitating subsequent oxygen release of the ARR process.Intriguingly,surface reorganization occurs following regulated Ni dissolution,enabling the stabilization of the surface and elimination of oxygen release in turn.Accordingly,a novel optimization strategy is proposed by adding a relaxation step at 4.50 V within the first cycle procedure.Battery performance can be effectively improved,with voltage decay suppressed from 3.44 mV/cycle to 1.60 mV/cycle,and cycle stability improved from 66.77%to 90.01%after 100 cycles.This work provides new perspectives for clarifying ARR surface instability and guidance for optimizing ARR performance.展开更多
We present a flexible manipulation and control of solitons via Bose-Einstein condensates.In the presence of Rashba spin-orbit coupling and repulsive interactions within a harmonic potential,our investigation reveals t...We present a flexible manipulation and control of solitons via Bose-Einstein condensates.In the presence of Rashba spin-orbit coupling and repulsive interactions within a harmonic potential,our investigation reveals the numerical local solutions within the system.By manipulating the strength of repulsive interactions and adjusting spin-orbit coupling while maintaining a zero-frequency rotation,diverse soliton structures emerge within the system.These include plane-wave solitons,two distinct types of stripe solitons,and odd petal solitons with both single and double layers.The stability of these solitons is intricately dependent on the varying strength of spin-orbit coupling.Specifically,stripe solitons can maintain a stable existence within regions characterized by enhanced spin-orbit coupling while petal solitons are unable to sustain a stable existence under similar conditions.When rotational frequency is introduced to the system,solitons undergo a transition from stripe solitons to a vortex array characterized by a sustained rotation.The rotational directions of clockwise and counterclockwise are non-equivalent owing to spin-orbit coupling.As a result,the properties of vortex solitons exhibit significant variation and are capable of maintaining a stable existence in the presence of repulsive interactions.展开更多
Gramicidin A(gA)is a kind of antibiotic peptide produced by bacillus brevis and it can dimerize across lipid bilayers to form a monovalent cation channel.In this work,we investigate the impact of cholesterol in the li...Gramicidin A(gA)is a kind of antibiotic peptide produced by bacillus brevis and it can dimerize across lipid bilayers to form a monovalent cation channel.In this work,we investigate the impact of cholesterol in the lipid bilayer on the binding of potassium ions with the gA channel and the transport of the ions across the channel.The results indicate that cholesterol can significantly influence the conformational stability of the gA channel and cause the channel deformation which inhibits the potassium ion binding with the channel and transport across the channel.The work provides some molecular insights into understanding of influence of lipids on the activity of gA channel in both model membranes and plasma membranes of intact cells.展开更多
Poor bone quality is a major factor in skeletal fragility in elderly individuals.The molecular mechanisms that establish and maintain bone quality,independent of bone mass,are unknown but are thought to be primarily d...Poor bone quality is a major factor in skeletal fragility in elderly individuals.The molecular mechanisms that establish and maintain bone quality,independent of bone mass,are unknown but are thought to be primarily determined by osteocytes.We hypothesize that the age-related decline in bone quality results from the suppression of osteocyte perilacunar/canalicular remodeling(PLR),which maintains bone material properties.We examined bones from young and aged mice with osteocyte-intrinsic repression of TGFβsignaling(TβRII^(ocy−/−))that suppresses PLR.The control aged bone displayed decreased TGFβsignaling and PLR,but aging did not worsen the existing PLR suppression in male TβRII^(ocy−/−)bone.This relationship impacted the behavior of collagen material at the nanoscale and tissue scale in macromechanical tests.The effects of age on bone mass,density,and mineral material behavior were independent of osteocytic TGFβ.We determined that the decline in bone quality with age arises from the loss of osteocyte function and the loss of TGFβ-dependent maintenance of collagen integrity.展开更多
Neuroimaging has emerged over the last few decades as a crucial tool in diagnosing Alzheimer’s disease(AD).Mild cognitive impairment(MCI)is a condition that falls between the spectrum of normal cognitive function and...Neuroimaging has emerged over the last few decades as a crucial tool in diagnosing Alzheimer’s disease(AD).Mild cognitive impairment(MCI)is a condition that falls between the spectrum of normal cognitive function and AD.However,previous studies have mainly used handcrafted features to classify MCI,AD,and normal control(NC)individuals.This paper focuses on using gray matter(GM)scans obtained through magnetic resonance imaging(MRI)for the diagnosis of individuals with MCI,AD,and NC.To improve classification performance,we developed two transfer learning strategies with data augmentation(i.e.,shear range,rotation,zoom range,channel shift).The first approach is a deep Siamese network(DSN),and the second approach involves using a cross-domain strategy with customized VGG-16.We performed experiments on the Alzheimer’s Disease Neuroimaging Initiative(ADNI)dataset to evaluate the performance of our proposed models.Our experimental results demonstrate superior performance in classifying the three binary classification tasks:NC vs.AD,NC vs.MCI,and MCI vs.AD.Specifically,we achieved a classification accuracy of 97.68%,94.25%,and 92.18%for the three cases,respectively.Our study proposes two transfer learning strategies with data augmentation to accurately diagnose MCI,AD,and normal control individuals using GM scans.Our findings provide promising results for future research and clinical applications in the early detection and diagnosis of AD.展开更多
We investigate spatiotemporal periodic patterns in harmonically trapped Bose–Einstein condensates(BECs)driven by a periodic modulation of the interaction.Resonant with the breathing mode,we show the emergence of a sq...We investigate spatiotemporal periodic patterns in harmonically trapped Bose–Einstein condensates(BECs)driven by a periodic modulation of the interaction.Resonant with the breathing mode,we show the emergence of a square lattice pattern containing two orthonormal stripes.We study the time evolutions of the lattice patterns for different driving strengths and dissipations.We find that its spatial periodicity and temporal oscillating frequency match the Bogoliubov dispersion,which is the intrinsic property of the system and relevant to the parametric amplification of elementary excitations.In the circumstances of strong driving strength and low dissipation,we further observe the triad interaction and the resulting superlattice state,which are well explained by the nonlinear amplitude equation for superimposed stripes.These results shed light on unexplored nonlinear spatiotemporal dynamics of two-dimensional patterns in harmonically trapped BECs that can pave the way for engineering exotic patterns by state-of-the-art experiments.展开更多
The polysulfides shuttle effect represents a great challenge in achieving high capacity and long lifespan of lithium/sulfur(Li/S)cells.A comprehensive understanding of the shuttle-related sulfur speciation and diffusi...The polysulfides shuttle effect represents a great challenge in achieving high capacity and long lifespan of lithium/sulfur(Li/S)cells.A comprehensive understanding of the shuttle-related sulfur speciation and diffusion process is vital for addressing this issue.Herein,we employed in situ/operando X-ray absorption spectroscopy(XAS)to trace the migration of polysulfides across the Li/S cells by precisely monitoring the sulfur chemical speciation at the cathodic electrolyte-separator and electrolyte-anode interfaces,respectively,in a real-time condition.After we adopted a shuttle-suppressing strategy by introducing an electrocatalytic layer of twinborn bismuth sulfide/bismuth oxide nanoclusters in a carbon matrix(BSOC),we found the Li/S cell showed greatly improved sulfur utilization and longer life span.The operando S Kedge XAS results revealed that the BSOC modification was bi-functional:trapping polysulfides and catalyzing conversion of sulfur species simultaneously.We elucidated that the polysulfide trapping-and-catalyzing effect of the BSOC electrocatalytic layer resulted in an effective lithium anode protection.Our results could offer potential stratagem for designing more advanced Li/S cells.展开更多
Here we demonstrate a theory-driven, novel dual-shell coating system of Li_(2)SrSiO_(4) and Al_(2)O_(3), achieved via a facile and scalable sol-gel technique on LiCoO_(2) electrode particles. The optimal thickness of ...Here we demonstrate a theory-driven, novel dual-shell coating system of Li_(2)SrSiO_(4) and Al_(2)O_(3), achieved via a facile and scalable sol-gel technique on LiCoO_(2) electrode particles. The optimal thickness of each coating can lead to increased specific capacity(~185 m Ah/g at 0.5 C-rate) at a cut-off potential of 4.5 V, and greater cycling stability at very high C rates(up to 10 C) in half-cells with lithium metal. The mechanism of this superior performance was investigated using a combination of X-ray and electron characterization methods. It shows that the results of this investigation can inform future studies to identify still better dual-shell coating schemes, achieved by such industrially feasible techniques, for application on similar, nickel-rich cathode materials.展开更多
A hard/soft SmCo5/ Fe nanocomposite magnetic bilayer system is fabricated on x-ray transparent 100-200 nm thin SiaN4 films by magnetron sputtering. The microscopic magnetic domain pattern and its behaviours during mag...A hard/soft SmCo5/ Fe nanocomposite magnetic bilayer system is fabricated on x-ray transparent 100-200 nm thin SiaN4 films by magnetron sputtering. The microscopic magnetic domain pattern and its behaviours during magnetization reversal in the hard and the soft magnetic phases are studied separately by element specific magnetic soft x-ray microscopy at a spatial resolution of better than 25 Nm. We observe that the domain patterns for the soft and hard phases show coherent behaviours in varying magnetic fields. We derive local M（H） curves from the images of Fe and SmCo5 separately and find the switches for hard and soft phases to be the same.展开更多
Fast charging and high-power delivering batteries are highly demanded in mobile electronics,electric vehicles and grid energy storage,but there are full of challenges.The star-material Li_(3)V_(2)(PO_(4))_(3) is demon...Fast charging and high-power delivering batteries are highly demanded in mobile electronics,electric vehicles and grid energy storage,but there are full of challenges.The star-material Li_(3)V_(2)(PO_(4))_(3) is demonstrated as a promising high-rate cathode material meeting the above requirements.Herein,we report the carbon decorated Li_(3)V_(2)(PO_(4))_(3) (LVP/C) cathode prepared via a facile method,which displays a remarkable high-rate capability and long-term cycling performance.Briefly,the prepared LVP/C delivers a high discharge capacity of 122 mAh g^(-1)(-93% of the theoretical capacity) at a high rate up to 20 C and a superior capacity retention of 87.1% after 1000 cycles.Importantly,by applying a combination of X-ray absorption spectroscopy and full-range mapping of resonant inelastic X-ray scattering,we clearly elucidate the structural and chemical evolutions of LVP upon various potentials and cycle numbers.We show unambiguous spectroscopic evidences that the evolution of the hybridization strength between V and O in LVP/C as a consequence of lithiation/delithiation is highly reversible both in the bulk and on the surface during the discharge-charge processes even over extended cycles,which should be responsible for the remarkable electrochemical performance of LVP/C.Our present study provides not only an effective synthesis strategy but also deeper insights into the surface and bulk electrochemical reaction mechanism of LVP,which should be beneficial for the further design of high-performance LVP electrode materials.展开更多
MgAl-LDH（layered double hydroxides） were prepared with CO（NH2）2, NH4 Cl and NH3·H2O by the coprecipitation method, respectively. Corresponding composite membranes were prepared by the coating method. LDHs wer...MgAl-LDH（layered double hydroxides） were prepared with CO（NH2）2, NH4 Cl and NH3·H2O by the coprecipitation method, respectively. Corresponding composite membranes were prepared by the coating method. LDHs were characterized by WAXS, CO2-TPD and SEM. The morphology of the PVC/LDHs composite membranes were characterized by means of SEM. The thermal stability of the membranes was analyzed by air aging box and TGA-FTIR. The SEM results show that nano-particles can be compatible with poly（vinyl chloride）（PVC） matrix homogeneously by the stirring-ultrasound blend method with two steps. Furthermore, the air aging box results proved that MgAl-CO（NH2）2-LDH has the best effect on thermal stability of PVC. TGA-FTIR results show that MgAl-CO（NH2）2-LDH could adsorb more HCl that resulted from the degradation of PVC and improve the pyrolysis temperature of the first degradation stage by 15 K compared with PVC.展开更多
A new photon-in/photon-out endstation at beamline 02B02 of the Shanghai Synchrotron Radiation Facility for studying the electronic structure of energy materials has been constructed and fully opened to users.The endst...A new photon-in/photon-out endstation at beamline 02B02 of the Shanghai Synchrotron Radiation Facility for studying the electronic structure of energy materials has been constructed and fully opened to users.The endstation has the capability to perform soft x-ray absorption spectroscopy in total electron yield and total fluorescence yield modes simultaneously.The photon energy ranges from 40 eV to 2000 eV covering the K-edge of most low Z-elements and the L-edge of 3d transition-metals.The new self-designed channeltron detector allows us to achieve good fluorescence signals at the low photon flux.In addition,we synchronously collect the signals of a standard reference sample and a gold mesh on the upstream to calibrate the photon energy and monitor the beam fluctuation,respectively.In order to cross the pressure gap,in situ gas and liquid cells for soft x-ray absorption spectroscopy are developed to study the samples under realistic working conditions.展开更多
Precisely quantifying transition metal(TM) redox in bulk is a key to understand the fundamental of optimizing cathode materials in secondary batteries. At present, the commonly used methods to probe TM redox are hard ...Precisely quantifying transition metal(TM) redox in bulk is a key to understand the fundamental of optimizing cathode materials in secondary batteries. At present, the commonly used methods to probe TM redox are hard X-ray absorption spectroscopy(hXAS) and soft X-ray absorption spectroscopy(sXAS).However, they are both facing challenges to precisely quantify the valence states of some transition metals such as Mn. In this paper, Mn-L iPFY(inverse partial fluorescence yield) spectra extracted from Mn-L m RIXS(mapping of resonant inelastic X-ray scattering) is adopted to quantify Mn valence states. Mn-L i PFY spectra has been considered as a bulk-sensitive, non-distorted probe of TM valence states.However, the exact precision of this method is still unclear in quantifying practical battery electrodes.Herein, a series of LiMn_(2)O_(4) electrodes with different charge and discharge states are prepared. Based on their electrochemical capacity(generally considered to be very precise), the precision of Mn iPFY in quantifying bulk Mn valence state is confirmed, and the error range is unraveled. Mn-L mRIXS iPFY thus is identified as one of the best methods to quantify the bulk Mn valence state comparing with hXAS and sXAS.展开更多
Understanding electronic structure is crucial to enhance the battery performance.Soft X-ray spectroscopy(SXS)is one of the most effective methods to provide direct probe of electronic states.Here,spectroscopic measure...Understanding electronic structure is crucial to enhance the battery performance.Soft X-ray spectroscopy(SXS)is one of the most effective methods to provide direct probe of electronic states.Here,spectroscopic measurements of transition metal 3 d and oxygen 2 p states are simply reviewed.Then,we mainly focus on the perspective of the development direction of modern SXS techniques.Although the true power of recently developed high efficiency mapping of resonant inelastic X-ray scattering(m RIXS)has been apparent for materials and chemistry studies,great challenges remain for mRIXS spectroscopic interpretation,and the understanding of the battery materials on novel redox activities remains elusive.展开更多
The lightweight,rechargeable lithium-ion battery is one of the dominant energy storage devices globally in portable electronics due to its high energy density,no memory effect,wide operating voltage,lightweight,and go...The lightweight,rechargeable lithium-ion battery is one of the dominant energy storage devices globally in portable electronics due to its high energy density,no memory effect,wide operating voltage,lightweight,and good charge efficiency.However,due to safety concerns,the depletion of lithium reserves,and the corresponding increase of cost,an alternative battery system becomes more and more desirable.To develop alternative battery systems with low cost and high material abundance,for example,sodium,magnesium,zinc,and calcium,it is important to understand the chemical and electronic structure of materials.Soft X-ray spectroscopy,for example,X-ray absorption spectroscopy(XAS),X-ray emission spectroscopy(XES),and resonant inelastic soft X-ray scattering(RIXS),is an element-specific technique with sensitivity to the local chemical environment and structural order of the element of interest.Modern soft X-ray systems enable operando experiments that can be applied to amorphous and crystalline samples,making it a powerful tool for studying the electronic and structural changes in electrode and electrolyte species.In this article,the application of in situ/operando(soft)X-ray spectroscopy in beyond lithium-ion batteries is reviewed to demonstrate how such spectroscopic characterizations could facilitate the interpretation of interfacial phenomena under in situ/operando condition and subsequent development of the beyond lithium-ion batteries.展开更多
Polyelectrolyte-surfactant complexes（PESCs） were fabricated through the interaction of poly（acrylic acid） and four different cationic surfactants or their mixtures. PESC membranes were prepared by solution casting...Polyelectrolyte-surfactant complexes（PESCs） were fabricated through the interaction of poly（acrylic acid） and four different cationic surfactants or their mixtures. PESC membranes were prepared by solution casting method and were applied in ethanol recovery from aqueous solution via pervaporation. Elemental analysis（EA）, Fourier transform infrared spectroscopy（FTIR）, water contact angle（CA） measurement, differential scanning calorimetry（DSC） and X-ray scattering were employed to characterize the composition, structure and properties of PESCs. The results reveal that the investigated PESCs are similar in hydrophobicity but different in hierarchical nanostructures. In separating 5 wt% ethanol/water mixture, PESC membranes with high crystallinity will have both low flux and ethanol selectivity because of the high packing density and low permeability of crystalline regions. Meanwhile, the hierarchical nanostructures of PESC membranes change under pervaporation environment as was revealed by in situ synchrotron radiation X-ray scattering measurement. That is, the crystalline region could melt at high temperature in swelling state, thus consequently enhancing the ethanol selectivity.展开更多
文摘As an advanced 4^(th) generation synchrotron radiation facility,the Shenzhen Innovation Light-source Facility(SILF)storage ring is based on multi-bend achromat(MBA)lattices,enabling one to two orders of magnitude reduction in beam emittance compared to the 3^(rd) generation storage ring.This significantly enhance the radiation brightness and coherence.The multipole magnets of many types for SILF storage ring are under preliminary design,which require high integral field homogeneity.As a result,a dedicated pole tip optimization procedure with high efficiency is developed for quadrupole and sextupole magnets with Opera-2D^(■)python script.The procedure considers also the 3D field effect which makes the optimization more straightforward.In this paper,the design of the quadrupole and sextupole magnets for SILF storage ring is first presented,followed by a detailed description of the implemented pole shape optimization method.
基金supported by Zhejiang Provincial Natural Science Foundation of China(Grant No.LZ25A040005)the National Natural Science Foundation of China(Grant No.11674287).
文摘The partitioning of membrane proteins into lipid domains in cellular membranes is closely associated with the realization of the protein functions and it is influenced by various factors such as the post-translational modification of palmitoylation.However,the molecular mechanism of the effect of palmitoylation on membrane protein partitioning into the lipid domains remains elusive.In this work,taking human peripheral myelin protein 22(PMP22)as an example,we employ coarse-grained molecular dynamics simulations to investigate the partitioning of both the natural PMP22 and the palmitoylated PMP22(pal-PMP22)into the lipid domains of model myelin membranes.The results indicate that palmitoylation drives PMP22 to localize at the boundary of the liquid-ordered(Lo)and liquid-disordered(Ld)domains and increases the possibility of PMP22 partitioning into the Lo domains by changing the hydrophobic length of the proteins and perturbing the ordered packing of tails of the saturated lipids in the Lo domains.This work offers some novel insights into the role of palmitoylation in modulating the function of membrane proteins in cellular membranes.
文摘In this study we theoretically demonstrate ultrahigh-resolution two-dimensional atomic localization within a three-levelλ-type atomic medium via superposition of asymmetric and symmetric standing wave fields.Our analysis provides an understanding of the precise spatial localization of atomic positions at the atomic level,utilizing advanced theoretical approaches and principles of quantum mechanics.The dynamical behavior of a three-level atomic system is thoroughly analyzed using the density matrix formalism within the realm of quantum mechanics.A theoretical approach is constructed to describe the interaction between the system and external fields,specifically a control field and a probe field.The absorption spectrum of the probe field is thoroughly examined to clarify the spatial localization of the atom within the proposed configuration.A theoretical investigation found that symmetric and asymmetric superposition phenomena significantly influence the localized peaks within a two-dimensional spatial domain.Specifically,the emergence of one and two sharp localized peaks was observed within a one-wavelength domain.We observed notable influences of the intensity of the control field,probe field detuning and decay rates on atomic localization.Ultimately,we have achieved an unprecedented level of ultrahigh resolution and precision in localizing an atom within an area smaller thanλ/35×λ/35.These findings hold promise for potential applications in fields such as Bose-Einstein condensation,nanolithography,laser cooling,trapping of neutral atoms and the measurement of center-of-mass wave functions.
基金Advanced Light Source,which is a DOE Office of Science User Facility under contract no.DE-AC02-05CH11231the Basque Government for funding through a PhD Fellowship(Grant no.PRE_2018_2_0285)+1 种基金through Egonlabur Travel Fellowship(Grant no.EP_2018_1_0004)partially supported by an Early Career Award in the Condensed Phase and Interfacial Molecular Science Program,in the Chemical Sciences Geosciences and Biosciences Division of the Office of Basic Energy Sciences of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231.
文摘The development of an analytical method for determining the properties of quantum dots(QDs)is crucial for improving the optical performance of QD-based displays.Therefore,synchrotron-based X-ray photoelectron spectroscopy(XPS)is designed here to accurately characterize the chemical and structural differences between different QDs.This method enables the determination of the reason for the minimal differences between the optical properties of different QDs depending on the synthesis process,which is difficult to determine using conventional methods alone.Combined with model simulations,the XPS spectra obtained at different photon energies reveal the internal structures and chemical-state distributions of the QDs.In particular,the QD synthesized under optimal conditions demonstrates a relatively lower degree of oxidation of the core and more uniformly stacked ZnSe/ZnS shell layers.The internal structures and chemical-state distributions of QDs are closely related to their optical properties.Finally,the synchrotron-based XPS proposed here can be applied to compare nearly equivalent QDs with slightly different optical properties.
基金supported by the National Key Research and Development Program (2019YFA0405601)National Science Foundation of China(No. 22309097, 22179066, 21902179)+1 种基金Shandong Provincial Natural Science Foundation (2023KJ228, ZR2021QE061, ZR202103010205)the Startup Foundation for Advanced Talents in Qingdao University (DC2000005106)
文摘Anionic redox reaction(ARR)can provide extra capacity beyond transition metal(TM)redox in lithium-rich TM oxide cathodes.Practical ARR application is much hindered by the structure instability,particularly at the surface.Oxygen release has been widely accepted as the ringleader of surficial structure instability.However,the role of TM in surface stability has been much overlooked,not to mention its interplay with oxygen release.Herein,TM dissolution and oxygen release are comparatively investigated in Li_(1.2)Ni_(0.2)Mn_(0.6)O_(2).Ni is verified to detach from the lattice counter-intuitively despite the overwhelming stoichiometry of Mn,facilitating subsequent oxygen release of the ARR process.Intriguingly,surface reorganization occurs following regulated Ni dissolution,enabling the stabilization of the surface and elimination of oxygen release in turn.Accordingly,a novel optimization strategy is proposed by adding a relaxation step at 4.50 V within the first cycle procedure.Battery performance can be effectively improved,with voltage decay suppressed from 3.44 mV/cycle to 1.60 mV/cycle,and cycle stability improved from 66.77%to 90.01%after 100 cycles.This work provides new perspectives for clarifying ARR surface instability and guidance for optimizing ARR performance.
基金the Natural Science Foundation of Zhejiang Province of China(Grant No.LZ22A050002)the National Natural Science Foundation of China(Grant Nos.12074343 and 11835011)Muhammad Idrees acknowledges support from the postdoctoral fellowship of Zhejiang Normal University(Grant No.YS304123952).
文摘We present a flexible manipulation and control of solitons via Bose-Einstein condensates.In the presence of Rashba spin-orbit coupling and repulsive interactions within a harmonic potential,our investigation reveals the numerical local solutions within the system.By manipulating the strength of repulsive interactions and adjusting spin-orbit coupling while maintaining a zero-frequency rotation,diverse soliton structures emerge within the system.These include plane-wave solitons,two distinct types of stripe solitons,and odd petal solitons with both single and double layers.The stability of these solitons is intricately dependent on the varying strength of spin-orbit coupling.Specifically,stripe solitons can maintain a stable existence within regions characterized by enhanced spin-orbit coupling while petal solitons are unable to sustain a stable existence under similar conditions.When rotational frequency is introduced to the system,solitons undergo a transition from stripe solitons to a vortex array characterized by a sustained rotation.The rotational directions of clockwise and counterclockwise are non-equivalent owing to spin-orbit coupling.As a result,the properties of vortex solitons exhibit significant variation and are capable of maintaining a stable existence in the presence of repulsive interactions.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674287)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY19A040009)。
文摘Gramicidin A(gA)is a kind of antibiotic peptide produced by bacillus brevis and it can dimerize across lipid bilayers to form a monovalent cation channel.In this work,we investigate the impact of cholesterol in the lipid bilayer on the binding of potassium ions with the gA channel and the transport of the ions across the channel.The results indicate that cholesterol can significantly influence the conformational stability of the gA channel and cause the channel deformation which inhibits the potassium ion binding with the channel and transport across the channel.The work provides some molecular insights into understanding of influence of lipids on the activity of gA channel in both model membranes and plasma membranes of intact cells.
文摘Poor bone quality is a major factor in skeletal fragility in elderly individuals.The molecular mechanisms that establish and maintain bone quality,independent of bone mass,are unknown but are thought to be primarily determined by osteocytes.We hypothesize that the age-related decline in bone quality results from the suppression of osteocyte perilacunar/canalicular remodeling(PLR),which maintains bone material properties.We examined bones from young and aged mice with osteocyte-intrinsic repression of TGFβsignaling(TβRII^(ocy−/−))that suppresses PLR.The control aged bone displayed decreased TGFβsignaling and PLR,but aging did not worsen the existing PLR suppression in male TβRII^(ocy−/−)bone.This relationship impacted the behavior of collagen material at the nanoscale and tissue scale in macromechanical tests.The effects of age on bone mass,density,and mineral material behavior were independent of osteocytic TGFβ.We determined that the decline in bone quality with age arises from the loss of osteocyte function and the loss of TGFβ-dependent maintenance of collagen integrity.
基金Research work funded by Zhejiang Normal University Research Fund YS304023947 and YS304023948.
文摘Neuroimaging has emerged over the last few decades as a crucial tool in diagnosing Alzheimer’s disease(AD).Mild cognitive impairment(MCI)is a condition that falls between the spectrum of normal cognitive function and AD.However,previous studies have mainly used handcrafted features to classify MCI,AD,and normal control(NC)individuals.This paper focuses on using gray matter(GM)scans obtained through magnetic resonance imaging(MRI)for the diagnosis of individuals with MCI,AD,and NC.To improve classification performance,we developed two transfer learning strategies with data augmentation(i.e.,shear range,rotation,zoom range,channel shift).The first approach is a deep Siamese network(DSN),and the second approach involves using a cross-domain strategy with customized VGG-16.We performed experiments on the Alzheimer’s Disease Neuroimaging Initiative(ADNI)dataset to evaluate the performance of our proposed models.Our experimental results demonstrate superior performance in classifying the three binary classification tasks:NC vs.AD,NC vs.MCI,and MCI vs.AD.Specifically,we achieved a classification accuracy of 97.68%,94.25%,and 92.18%for the three cases,respectively.Our study proposes two transfer learning strategies with data augmentation to accurately diagnose MCI,AD,and normal control individuals using GM scans.Our findings provide promising results for future research and clinical applications in the early detection and diagnosis of AD.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.12074343(WW and HJL)the Natural Science Foundation of Zhejiang Province of China under Grant No.LZ22A050002(HJL)。
文摘We investigate spatiotemporal periodic patterns in harmonically trapped Bose–Einstein condensates(BECs)driven by a periodic modulation of the interaction.Resonant with the breathing mode,we show the emergence of a square lattice pattern containing two orthonormal stripes.We study the time evolutions of the lattice patterns for different driving strengths and dissipations.We find that its spatial periodicity and temporal oscillating frequency match the Bogoliubov dispersion,which is the intrinsic property of the system and relevant to the parametric amplification of elementary excitations.In the circumstances of strong driving strength and low dissipation,we further observe the triad interaction and the resulting superlattice state,which are well explained by the nonlinear amplitude equation for superimposed stripes.These results shed light on unexplored nonlinear spatiotemporal dynamics of two-dimensional patterns in harmonically trapped BECs that can pave the way for engineering exotic patterns by state-of-the-art experiments.
基金financially supported by the National Key R&D Program of China(2016YFB0100100)the National Natural Science Foundation of China(Nos.21433013,U1832218)the support from China Scholarship Council
文摘The polysulfides shuttle effect represents a great challenge in achieving high capacity and long lifespan of lithium/sulfur(Li/S)cells.A comprehensive understanding of the shuttle-related sulfur speciation and diffusion process is vital for addressing this issue.Herein,we employed in situ/operando X-ray absorption spectroscopy(XAS)to trace the migration of polysulfides across the Li/S cells by precisely monitoring the sulfur chemical speciation at the cathodic electrolyte-separator and electrolyte-anode interfaces,respectively,in a real-time condition.After we adopted a shuttle-suppressing strategy by introducing an electrocatalytic layer of twinborn bismuth sulfide/bismuth oxide nanoclusters in a carbon matrix(BSOC),we found the Li/S cell showed greatly improved sulfur utilization and longer life span.The operando S Kedge XAS results revealed that the BSOC modification was bi-functional:trapping polysulfides and catalyzing conversion of sulfur species simultaneously.We elucidated that the polysulfide trapping-and-catalyzing effect of the BSOC electrocatalytic layer resulted in an effective lithium anode protection.Our results could offer potential stratagem for designing more advanced Li/S cells.
基金supported by the U.S. National Science Foundation (CBET-1949870, CBET-2016192, and DMR-1832803)Part of the research was conducted at the Northwest Nanotechnology Infrastructure, a National Nanotechnology Coordinated Infrastructure (NNCI) site at Oregon State University, which is supported, in part, by the U.S. National Science Foundation (NNCI-1542101 and NCC-2025489), and Oregon State University。
文摘Here we demonstrate a theory-driven, novel dual-shell coating system of Li_(2)SrSiO_(4) and Al_(2)O_(3), achieved via a facile and scalable sol-gel technique on LiCoO_(2) electrode particles. The optimal thickness of each coating can lead to increased specific capacity(~185 m Ah/g at 0.5 C-rate) at a cut-off potential of 4.5 V, and greater cycling stability at very high C rates(up to 10 C) in half-cells with lithium metal. The mechanism of this superior performance was investigated using a combination of X-ray and electron characterization methods. It shows that the results of this investigation can inform future studies to identify still better dual-shell coating schemes, achieved by such industrially feasible techniques, for application on similar, nickel-rich cathode materials.
基金Project supported by the Higher Education Commission of Pakistan under International Research Support Initiative Program and partially supported by BES/DOE funding
文摘A hard/soft SmCo5/ Fe nanocomposite magnetic bilayer system is fabricated on x-ray transparent 100-200 nm thin SiaN4 films by magnetron sputtering. The microscopic magnetic domain pattern and its behaviours during magnetization reversal in the hard and the soft magnetic phases are studied separately by element specific magnetic soft x-ray microscopy at a spatial resolution of better than 25 Nm. We observe that the domain patterns for the soft and hard phases show coherent behaviours in varying magnetic fields. We derive local M（H） curves from the images of Fe and SmCo5 separately and find the switches for hard and soft phases to be the same.
基金supported by Collaborative Innovation Center of Suzhou Nano Science & Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)+5 种基金the 111 roject, Joint International Research Laboratory of Carbon-Based Functional Materials and Devicesthe National Natural Science Foundation of China (11905154)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (19KJA550004)the Natural Science Foundation of Jiangsu Province (BK20190814)the National Key R&D Program of China (No. 2016YFA0202600)supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231。
文摘Fast charging and high-power delivering batteries are highly demanded in mobile electronics,electric vehicles and grid energy storage,but there are full of challenges.The star-material Li_(3)V_(2)(PO_(4))_(3) is demonstrated as a promising high-rate cathode material meeting the above requirements.Herein,we report the carbon decorated Li_(3)V_(2)(PO_(4))_(3) (LVP/C) cathode prepared via a facile method,which displays a remarkable high-rate capability and long-term cycling performance.Briefly,the prepared LVP/C delivers a high discharge capacity of 122 mAh g^(-1)(-93% of the theoretical capacity) at a high rate up to 20 C and a superior capacity retention of 87.1% after 1000 cycles.Importantly,by applying a combination of X-ray absorption spectroscopy and full-range mapping of resonant inelastic X-ray scattering,we clearly elucidate the structural and chemical evolutions of LVP upon various potentials and cycle numbers.We show unambiguous spectroscopic evidences that the evolution of the hybridization strength between V and O in LVP/C as a consequence of lithiation/delithiation is highly reversible both in the bulk and on the surface during the discharge-charge processes even over extended cycles,which should be responsible for the remarkable electrochemical performance of LVP/C.Our present study provides not only an effective synthesis strategy but also deeper insights into the surface and bulk electrochemical reaction mechanism of LVP,which should be beneficial for the further design of high-performance LVP electrode materials.
基金supported by the Shanghai Municipal Education Commission with“Twelfth Five”scientific connotation construction project(No.nhky-2012-05)foreign visiting scholar fellowship program(No.B-8938-12-0406)Opening Project of Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering
文摘MgAl-LDH（layered double hydroxides） were prepared with CO（NH2）2, NH4 Cl and NH3·H2O by the coprecipitation method, respectively. Corresponding composite membranes were prepared by the coating method. LDHs were characterized by WAXS, CO2-TPD and SEM. The morphology of the PVC/LDHs composite membranes were characterized by means of SEM. The thermal stability of the membranes was analyzed by air aging box and TGA-FTIR. The SEM results show that nano-particles can be compatible with poly（vinyl chloride）（PVC） matrix homogeneously by the stirring-ultrasound blend method with two steps. Furthermore, the air aging box results proved that MgAl-CO（NH2）2-LDH has the best effect on thermal stability of PVC. TGA-FTIR results show that MgAl-CO（NH2）2-LDH could adsorb more HCl that resulted from the degradation of PVC and improve the pyrolysis temperature of the first degradation stage by 15 K compared with PVC.
基金Project supported by the National Natural Science Foundation of China(Grant No.11227902)as part of NSFC ME2 beamline project,Science and Technology Commission of Shanghai Municipality,China(Grant No.14520722100)the National Natural Science Foundation of China(Grant Nos.11905283 and U1632269)
文摘A new photon-in/photon-out endstation at beamline 02B02 of the Shanghai Synchrotron Radiation Facility for studying the electronic structure of energy materials has been constructed and fully opened to users.The endstation has the capability to perform soft x-ray absorption spectroscopy in total electron yield and total fluorescence yield modes simultaneously.The photon energy ranges from 40 eV to 2000 eV covering the K-edge of most low Z-elements and the L-edge of 3d transition-metals.The new self-designed channeltron detector allows us to achieve good fluorescence signals at the low photon flux.In addition,we synchronously collect the signals of a standard reference sample and a gold mesh on the upstream to calibrate the photon energy and monitor the beam fluctuation,respectively.In order to cross the pressure gap,in situ gas and liquid cells for soft x-ray absorption spectroscopy are developed to study the samples under realistic working conditions.
基金the support from the key research and development and promotion of special projects (scientific and technological research) of Henan province (212102210188)the National Natural Science Foundation of China (51604244)the Energy Storage Materials and Processes Key Laboratory of Henan Province Open Fund (2021003)。
文摘Precisely quantifying transition metal(TM) redox in bulk is a key to understand the fundamental of optimizing cathode materials in secondary batteries. At present, the commonly used methods to probe TM redox are hard X-ray absorption spectroscopy(hXAS) and soft X-ray absorption spectroscopy(sXAS).However, they are both facing challenges to precisely quantify the valence states of some transition metals such as Mn. In this paper, Mn-L iPFY(inverse partial fluorescence yield) spectra extracted from Mn-L m RIXS(mapping of resonant inelastic X-ray scattering) is adopted to quantify Mn valence states. Mn-L i PFY spectra has been considered as a bulk-sensitive, non-distorted probe of TM valence states.However, the exact precision of this method is still unclear in quantifying practical battery electrodes.Herein, a series of LiMn_(2)O_(4) electrodes with different charge and discharge states are prepared. Based on their electrochemical capacity(generally considered to be very precise), the precision of Mn iPFY in quantifying bulk Mn valence state is confirmed, and the error range is unraveled. Mn-L mRIXS iPFY thus is identified as one of the best methods to quantify the bulk Mn valence state comparing with hXAS and sXAS.
文摘Understanding electronic structure is crucial to enhance the battery performance.Soft X-ray spectroscopy(SXS)is one of the most effective methods to provide direct probe of electronic states.Here,spectroscopic measurements of transition metal 3 d and oxygen 2 p states are simply reviewed.Then,we mainly focus on the perspective of the development direction of modern SXS techniques.Although the true power of recently developed high efficiency mapping of resonant inelastic X-ray scattering(m RIXS)has been apparent for materials and chemistry studies,great challenges remain for mRIXS spectroscopic interpretation,and the understanding of the battery materials on novel redox activities remains elusive.
基金supported as part of the Joint Center for Energy Storage Research(JCESR)an Energy Innovation Hub funded by the U.S.Department of Energy(DOE),Office of Science,Basic Energy Sciences
文摘The lightweight,rechargeable lithium-ion battery is one of the dominant energy storage devices globally in portable electronics due to its high energy density,no memory effect,wide operating voltage,lightweight,and good charge efficiency.However,due to safety concerns,the depletion of lithium reserves,and the corresponding increase of cost,an alternative battery system becomes more and more desirable.To develop alternative battery systems with low cost and high material abundance,for example,sodium,magnesium,zinc,and calcium,it is important to understand the chemical and electronic structure of materials.Soft X-ray spectroscopy,for example,X-ray absorption spectroscopy(XAS),X-ray emission spectroscopy(XES),and resonant inelastic soft X-ray scattering(RIXS),is an element-specific technique with sensitivity to the local chemical environment and structural order of the element of interest.Modern soft X-ray systems enable operando experiments that can be applied to amorphous and crystalline samples,making it a powerful tool for studying the electronic and structural changes in electrode and electrolyte species.In this article,the application of in situ/operando(soft)X-ray spectroscopy in beyond lithium-ion batteries is reviewed to demonstrate how such spectroscopic characterizations could facilitate the interpretation of interfacial phenomena under in situ/operando condition and subsequent development of the beyond lithium-ion batteries.
基金financially supported by the National Natural Science Foundation of China(Nos.21376206 and 21676233)Zhejiang Province Natural Science Foundation(No.LR15B060001)
文摘Polyelectrolyte-surfactant complexes（PESCs） were fabricated through the interaction of poly（acrylic acid） and four different cationic surfactants or their mixtures. PESC membranes were prepared by solution casting method and were applied in ethanol recovery from aqueous solution via pervaporation. Elemental analysis（EA）, Fourier transform infrared spectroscopy（FTIR）, water contact angle（CA） measurement, differential scanning calorimetry（DSC） and X-ray scattering were employed to characterize the composition, structure and properties of PESCs. The results reveal that the investigated PESCs are similar in hydrophobicity but different in hierarchical nanostructures. In separating 5 wt% ethanol/water mixture, PESC membranes with high crystallinity will have both low flux and ethanol selectivity because of the high packing density and low permeability of crystalline regions. Meanwhile, the hierarchical nanostructures of PESC membranes change under pervaporation environment as was revealed by in situ synchrotron radiation X-ray scattering measurement. That is, the crystalline region could melt at high temperature in swelling state, thus consequently enhancing the ethanol selectivity.
