There is an urgent need for high-quality and high-frequency clock generators for high-energy physics experiments.The transmission data rate exceeds 10 Gbps for a single channel in future readout electronics of silicon...There is an urgent need for high-quality and high-frequency clock generators for high-energy physics experiments.The transmission data rate exceeds 10 Gbps for a single channel in future readout electronics of silicon pixel detectors.Others,such as time measurement detectors,require a high time resolution based on the time-to-digital readout architecture.A phase-locked loop(PLL)is an essential and broadly used circuit in these applications.This study presents an application-specific integrated circuit of a low-jitter,low-power LC-tank that is PLL fabricated using 55-nm CMOS technology.It includes a 3rd-order frequency synthesis loop with a programmable bandwidth,a divide-by-2 pre-scaler,standard low-voltage differential signaling interfaces,and a current mode logic(CML)driver for clock transmissions.All the d-flip-flop dividers and phase-frequency detectors are protected from single-event upsets using the triple modular redundancy technique.The proposed VCO uses low-pass filters to suppress the noise from bias circuits.The tested LC-PLL covers a frequency locking range between 4.74 GHz and 5.92 GHz with two sub-bands.The jitter measurements of the frequency-halved clock(2.56 GHz)are less than 460 fs and 0.8 ps for the random and deterministic jitters,respectively,and a total of 7.5 ps peak-to-peak with a bit error rate of 10^(-12).The random and total jitter values for frequencies of 426 MHz and 20 MHz are less than 1.8 ps and 65 ps,respectively.The LC-PLL consumed 27 mW for the core and 73.8 mW in total.The measured results nearly coincided with the simulations and validated the analyses and tests.展开更多
Elastic scattering differential cross sections for a p- ~4He system are calculated within the framework of optical limit approximation of the Glauber multiple scattering model. Three different ranges for proton energy...Elastic scattering differential cross sections for a p- ~4He system are calculated within the framework of optical limit approximation of the Glauber multiple scattering model. Three different ranges for proton energy(E_(lab)), 19〈E_(lab)〈50 Me V, 100≤E_(lab)≤1730 Me V, and 45 ≤E_(lab)≤393 Ge V are considered. It is shown that the Pauli blocking fails to describe the data up to the proton energy, E_(lab)〈100 Me V. For higher proton energies, a qualitative agreement is obtained. The observed elastic scattering differential cross section is nicely reproduced in the whole range of scattering angles in the center of mass system up to Θ_(c.m.)〈200° for 19〈E_(lab) ≤100 Me V when the effect of both the nucleon–nucleon(NN) phase variation parameter γNN and higher-order momentum transfer components(λ_n; n = 1 and 2) of(NN) elastic scattering amplitude is included. In the range of 200 E_(lab) 1730 Me V, introducing λ_n plays a significant role in describing the data up to the momentum transfer, q^2≤1:2(Ge V/c)~2.Moreover, it is found that considering only the effect of phase variation parameter, cNN, improved the agreement in the region of minima for elastic scattering differential cross section for 45≤E_(lab)≤393 Ge V. The values of cNNand kn as a function of incident proton energies are presented.展开更多
The activity concentration of natural radioactivity for soil samples collected from western and mid Libyan regions were measured using HPGe detector. The average activity concentration of 226Ra, 232Th and 40K for ten ...The activity concentration of natural radioactivity for soil samples collected from western and mid Libyan regions were measured using HPGe detector. The average activity concentration of 226Ra, 232Th and 40K for ten regions was found to be 51.86 ± 7.14, 75.56 ± 10.95 and 128.98 ± 6.88 Bq/kg respectively. The results obtained for the corresponding nuclides 226Ra and 232Th are above the worldwide average values (35 and 30 Bq/kg) while 40K was smaller than worldwide average (400 Bq/kg). The average outdoor absorbed dose and the annual effective dose rates due to 226Ra, 232Th and 40K were observed to be 21.51 ± 2.93 nGy/h and 0.297 ±.03 mSv/y respectively, which are lower than world average values (60 nGy/h and 0.8 mSv/y). The radium equivalent activity and external hazard indices were found less than the world wide average values.展开更多
In order to reveal the nature of dark matter,it is crucial to detect its non-gravitational interactions with the standard model particles.The traditional dark matter searches focused on the so-called weakly interactin...In order to reveal the nature of dark matter,it is crucial to detect its non-gravitational interactions with the standard model particles.The traditional dark matter searches focused on the so-called weakly interacting massive particles.However,this paradigm is strongly constrained by the null results of current experiments with high precision.Therefore there is a renewed interest of searches for heavy dark matter particles above TeV scale.The Large High Altitude Air Shower Observatory(LHAASO)with large effective area and strong background rejection power is very suitable to investigate the gamma-ray signals induced by dark matter annihilation or decay above TeV scale.In this document,we review the theoretical motivations and background of heavy dark matter.We review the prospects of searching for the gamma-ray signals resulted from dark matter in the dwarf spheroidal satellites and Galactic halo for LHAASO,and present the projected sensitivities.We also review the prospects of searching for the axion-like particles,which are a kind of well motivated light pseudo-scalars,through the LHAASO measurement of the very high energy gamma-ray spectra of astrophysical sources.展开更多
A1 doped SmFeO3 （SmFel_xmlxO3; 0.0〈x〈0.15; step 0.05） were prepared by double sintering ceramic technique. The obtained samples were crystallized in single phase structure except the sample with x=0.15. The unit c...A1 doped SmFeO3 （SmFel_xmlxO3; 0.0〈x〈0.15; step 0.05） were prepared by double sintering ceramic technique. The obtained samples were crystallized in single phase structure except the sample with x=0.15. The unit cell volume was found to decrease with increasing AI substitution in orthoferrite. The effective magnetic moment （μeff） and the Curie constant （C） were calculated from the reciprocal of the molar magnetic susceptibility （Z-1） versus absolute temperature plot and found to attain maximum value for the parent sample. The magnetic behavior showed two different magnetic transitions, viz, N6el temperature （TN） and spin reorientation （TsR） transitions. The M-H hysteresis loop of the parent sample took butterfly-shape as a result of different contributions anisotropies. From the magnetic properties measurements, it was obviously found that B-site cation dilution resulted in a drastic decrease in the magnetization. Surprisingly large value of the coercive field was obtained for the undoped sample;Hc=6198.80e. Based on the mentioned results, one can recommend the use of such orthoferrite in magnetic recording media and as pining layer in spin valve for spin- tronic applications.展开更多
An organic light-emitting diode （OLED） device with high efficiency and brightness is fabricated by inserting CuOJCu dual inorganic buffer layers between indium-tin-oxide （ITO） and hole-transport layer （HTL）. The...An organic light-emitting diode （OLED） device with high efficiency and brightness is fabricated by inserting CuOJCu dual inorganic buffer layers between indium-tin-oxide （ITO） and hole-transport layer （HTL）. The CuOx/Cu buffer layer limits the operating current density obviously, while the brightness and efficiency are both enhanced greatly. The highest brightness of the optimized device is achieved to be 14 000 cd/m2 at current efficiency of 3 cd/A and bias voltage of 15 V, which is about 50% higher than that of the compared device without CuOJCu buffer layer. The highest efficiency is achieved to be 5.9 cd/A at 11.6 V with 3 400 cd/m^2, which is almost twice as high as that of the compared device.展开更多
We present a device for passive unidirectional liquid transport. The capillary channels used are bioinspired by the shape of the spermathecae （receptaculum seminis） of rabbit fleas （Spilopsyllus cuniculi） and rat ...We present a device for passive unidirectional liquid transport. The capillary channels used are bioinspired by the shape of the spermathecae （receptaculum seminis） of rabbit fleas （Spilopsyllus cuniculi） and rat fleas （Xenopsytla cheopis）. The spermatheca is an organ of female fleas that stores sperm until suitable conditions to lay eggs are found. We translated and multiplied the natural form and function of a spermatheca to create a continuous capillary system from which we designed our microfluidic device based directly on the model from nature. Applying the Young-Laplace equation, we derived a theoretical description of local liquid transport, which enables model-guided design. We arranged the bioinspired capillaries in parallel and engraved them in poly（methyl methacrylate） （PMMA） plates by CO2 laser ablation. The fabricated structures transport soapy water passively （i.e., without external energy input） in the forward direction at velocities of about 1 mm＇s i while halting the liquid fronts completely in the backward direction. The bio- inspired capillary channels are capable of unidirectional liquid transport against gravity. Distance and velocity measurements prove the feasibility of the concept. Unidirectional passive liquid transport might be advantageous in technical surfaces for liquid man- agement, for instance, in biomedical microfluidics, lab-on-chip, lubrication, electronics cooling and in micro-analysis devices.展开更多
The development of new materials,having exceptional properties in comparison to existing materials is highly required for bringing advancement in electronic and optoelectronic technologies.Keeping this fact,we investi...The development of new materials,having exceptional properties in comparison to existing materials is highly required for bringing advancement in electronic and optoelectronic technologies.Keeping this fact,we investigated structural,electronic,and optical properties of zincblende GaN doped with selected Zn concentrations(6.25%,12.50%,and 18.70%),using the first-principle calculations based on density functional theory with GGA+U.We conducted the entire study using the WIEN2K code.In this study,we calculated various significant parametric quantities such as cohesive energies,formation energies,bulk moduli,and lattice constants along with the study of optical and electronic properties by substituting Ga atoms with Zn atoms in 1×2×2 supercell.The structural stability is confirmed by studying the phonon dispersion curves which suggest that Zn:GaN material is stable against the 6.25%and 18.70%Zn concentrations while for 12.50%,it shows instability.The Hubbard values U=0,2,4,6 eV were added to GGA and the electronic properties were improved with the U=6 eV.Optical absorption was blue shifted while the refractive index and dielectric constant were increased with increasing the Zn concentrations.Electronic properties are enhanced due to the prime contribution of cations(Zn)3ri states.The optical and electronic properties are further discussed in detail in the entire study.展开更多
The modification of amyloid fibrils cytotoxicity through exogenous nanomaterials is crucial to understand the processes controlling the role of protein aggregation in the related diseases.The influence of nanoparticle...The modification of amyloid fibrils cytotoxicity through exogenous nanomaterials is crucial to understand the processes controlling the role of protein aggregation in the related diseases.The influence of nanoparticles on amyloid stability yields great interest due to the small size and high surface area-to-volume ratio of nanoparticles.Various physico-chemical parameters play a role in the interaction of proteins and nanoparticles in solution,thus influencing the disaggregation of preformed fibrils.We have examined the influence of two kinds of metallic nanoparticles on lysozyme amyloid fibrils using a multi-technique approach and focalized their impact on cytotoxicity on human neuroblastoma cells(SH-SY5Y).In particular,fluorescence,infrared and circular dichroism spectroscopies,optical and atomic force microscopy experiments have been carried out;the results are analyzed to rationalize the effects of these complexes on neural cell viability.It is remarkable,that the fibrils in the presence of AuNPs,unlike fibrils alone or with AgNPs,do not generate a significant cytotoxic effect even at high concentration and an amyloid degradation effect is visible.展开更多
The paper is concerned with the characteristic features of the dislocation mechanism related to fatigue in ferroelectrics in the process of their repeated switching.In a polarized crystal,dislocations possess a charge...The paper is concerned with the characteristic features of the dislocation mechanism related to fatigue in ferroelectrics in the process of their repeated switching.In a polarized crystal,dislocations possess a charge the sign of which depends on the orientation of the spontaneous polarization vector relative to the dislocation line.In the process of hysteresis switching,the average force from the applied field acting on a charged dislocation for one period of the hysteresis loop is not equal to zero.Such long-acting force leads to the accumulation of defects near the surface,which can fix a polarization and so partially remove it from the switching process.The proposed mechanism explains the key dependences of the critical number of switching cycles on the field amplitude,frequency and temperature of the sample.展开更多
With the use of techniques of SawyerTower and Mertz method regularities of the origin of "fatigue"in thin ferroelectric films of lead titanate and lead zirconate titanate have been investigated in the field...With the use of techniques of SawyerTower and Mertz method regularities of the origin of "fatigue"in thin ferroelectric films of lead titanate and lead zirconate titanate have been investigated in the fields above coercive.We propose a model to explain the experimentally observed switching-dependent fatigue processes by the motion of charged dislocations in an applied external alternating electric field.展开更多
Rapidity-dependent transverse momentum spectra of negatively charged pions measured at different rapidities in proton-proton collisions at the Super Proton Synchrotron （SPS） at various energies within its Beam Energ...Rapidity-dependent transverse momentum spectra of negatively charged pions measured at different rapidities in proton-proton collisions at the Super Proton Synchrotron （SPS） at various energies within its Beam Energy Scan （BES） program are investigated by using one- and two-component standard distributions where the chemical potential and spin property of particles are implemented. The rapidity spectra are described by a double- Gaussian distribution. At the stage of kinetic freeze-out, the event patterns are structured by the scatter plots in the three-dimensional subspaces of velocity, momentum and rapidity. The results of the studies of the rapidityindependent transverse mass spectra measured at mid-rapidity in proton-proton collisions are compared with those based on the similar transverse mass spectra measured in the most central beryllium-beryllium, argon-scandium and lead-lead collisions from the SPS at its BES energies.展开更多
Methods capable of tuning the properties of van der Waals(vdW)layered materials in a controlled and reversible manner are highly desirable.Interfacial electronic properties of two-dimensional vdW heterostructure consi...Methods capable of tuning the properties of van der Waals(vdW)layered materials in a controlled and reversible manner are highly desirable.Interfacial electronic properties of two-dimensional vdW heterostructure consisting of silicene and indium selenide(InSe)have been calculated using density functional theory-based computational code.Furthermore,in order to vary the aforementioned properties,silicene is slid over a InSe layer in the presence of Li intercalation.On intercalation of the heterostructure,the buckling parameter associated with the corrugation of silicene decreases from 0.44A to 0.36A,whereas the InSe structure remains unaffected.Potential energy scans reveal a significant increase in the sliding energy barrier for the case of intercalated heterostructure as compared with the unintercalated heterostructure.The sliding of the silicene encounters the maximum energy barrier of 0.14 eV.Anisotropic analysis shows the noteworthy differences between calculated in-plane and out-of-plane part of dielectric function.A variation of the planar average charge density difference,dipole charge transfer and dipole moment have been discussed to elucidate the usability spectrum of the heterostructure.The employed approach based on intercalation and layer sliding can be effectively utilized for obtaining next-generation multifunctional devices.展开更多
In this paper,a 64 mm×64 mm matrix polymer solar cell(PSC) was fabricated by air-brush spray deposition.Although the open-circuit voltage(Voc) and the fill factor(FF) both need to be improved,the efficiency of ma...In this paper,a 64 mm×64 mm matrix polymer solar cell(PSC) was fabricated by air-brush spray deposition.Although the open-circuit voltage(Voc) and the fill factor(FF) both need to be improved,the efficiency of matrix PSCs still reaches about 1.82%,and especially the current density achieves nearly 20 m A/cm2.The results verify that air-brush spray deposition is a suitable method to prepare large area PSC devices,and the process we use in this paper can be easily transplanted to roll-to-roll production.展开更多
Using the vector exchange interaction in the local hidden gauge approach,which in the light quark sector generates the chiral Lagrangians and has produced realistic results for Ωc,Ξc,Ξb and the hidden charm pentaqu...Using the vector exchange interaction in the local hidden gauge approach,which in the light quark sector generates the chiral Lagrangians and has produced realistic results for Ωc,Ξc,Ξb and the hidden charm pentaquark states,we study the meson-baryon interactions in the coupled channels that lead to the Ξbb and Ωbbb excited states of the molecular type.We obtain seven states of the Ξbb type with energies between 10408 and 10869 MeV,and one Ωbbb state at 15212 MeV.展开更多
基金supported in part by the National Natural Science Foundation of China(Nos.12005245,12075100,and 11775244)by the Scientific and Technological Innovation Project(No.2020000165)from the Institute of High Energy Physics,Chinese Academy of Sciences+1 种基金partially funded by the Scientific Instrument Development Project of the Chinese Academy of Sciences(No.ZDKYYQ20200007)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y201905).
文摘There is an urgent need for high-quality and high-frequency clock generators for high-energy physics experiments.The transmission data rate exceeds 10 Gbps for a single channel in future readout electronics of silicon pixel detectors.Others,such as time measurement detectors,require a high time resolution based on the time-to-digital readout architecture.A phase-locked loop(PLL)is an essential and broadly used circuit in these applications.This study presents an application-specific integrated circuit of a low-jitter,low-power LC-tank that is PLL fabricated using 55-nm CMOS technology.It includes a 3rd-order frequency synthesis loop with a programmable bandwidth,a divide-by-2 pre-scaler,standard low-voltage differential signaling interfaces,and a current mode logic(CML)driver for clock transmissions.All the d-flip-flop dividers and phase-frequency detectors are protected from single-event upsets using the triple modular redundancy technique.The proposed VCO uses low-pass filters to suppress the noise from bias circuits.The tested LC-PLL covers a frequency locking range between 4.74 GHz and 5.92 GHz with two sub-bands.The jitter measurements of the frequency-halved clock(2.56 GHz)are less than 460 fs and 0.8 ps for the random and deterministic jitters,respectively,and a total of 7.5 ps peak-to-peak with a bit error rate of 10^(-12).The random and total jitter values for frequencies of 426 MHz and 20 MHz are less than 1.8 ps and 65 ps,respectively.The LC-PLL consumed 27 mW for the core and 73.8 mW in total.The measured results nearly coincided with the simulations and validated the analyses and tests.
文摘Elastic scattering differential cross sections for a p- ~4He system are calculated within the framework of optical limit approximation of the Glauber multiple scattering model. Three different ranges for proton energy(E_(lab)), 19〈E_(lab)〈50 Me V, 100≤E_(lab)≤1730 Me V, and 45 ≤E_(lab)≤393 Ge V are considered. It is shown that the Pauli blocking fails to describe the data up to the proton energy, E_(lab)〈100 Me V. For higher proton energies, a qualitative agreement is obtained. The observed elastic scattering differential cross section is nicely reproduced in the whole range of scattering angles in the center of mass system up to Θ_(c.m.)〈200° for 19〈E_(lab) ≤100 Me V when the effect of both the nucleon–nucleon(NN) phase variation parameter γNN and higher-order momentum transfer components(λ_n; n = 1 and 2) of(NN) elastic scattering amplitude is included. In the range of 200 E_(lab) 1730 Me V, introducing λ_n plays a significant role in describing the data up to the momentum transfer, q^2≤1:2(Ge V/c)~2.Moreover, it is found that considering only the effect of phase variation parameter, cNN, improved the agreement in the region of minima for elastic scattering differential cross section for 45≤E_(lab)≤393 Ge V. The values of cNNand kn as a function of incident proton energies are presented.
文摘The activity concentration of natural radioactivity for soil samples collected from western and mid Libyan regions were measured using HPGe detector. The average activity concentration of 226Ra, 232Th and 40K for ten regions was found to be 51.86 ± 7.14, 75.56 ± 10.95 and 128.98 ± 6.88 Bq/kg respectively. The results obtained for the corresponding nuclides 226Ra and 232Th are above the worldwide average values (35 and 30 Bq/kg) while 40K was smaller than worldwide average (400 Bq/kg). The average outdoor absorbed dose and the annual effective dose rates due to 226Ra, 232Th and 40K were observed to be 21.51 ± 2.93 nGy/h and 0.297 ±.03 mSv/y respectively, which are lower than world average values (60 nGy/h and 0.8 mSv/y). The radium equivalent activity and external hazard indices were found less than the world wide average values.
文摘In order to reveal the nature of dark matter,it is crucial to detect its non-gravitational interactions with the standard model particles.The traditional dark matter searches focused on the so-called weakly interacting massive particles.However,this paradigm is strongly constrained by the null results of current experiments with high precision.Therefore there is a renewed interest of searches for heavy dark matter particles above TeV scale.The Large High Altitude Air Shower Observatory(LHAASO)with large effective area and strong background rejection power is very suitable to investigate the gamma-ray signals induced by dark matter annihilation or decay above TeV scale.In this document,we review the theoretical motivations and background of heavy dark matter.We review the prospects of searching for the gamma-ray signals resulted from dark matter in the dwarf spheroidal satellites and Galactic halo for LHAASO,and present the projected sensitivities.We also review the prospects of searching for the axion-like particles,which are a kind of well motivated light pseudo-scalars,through the LHAASO measurement of the very high energy gamma-ray spectra of astrophysical sources.
文摘A1 doped SmFeO3 （SmFel_xmlxO3; 0.0〈x〈0.15; step 0.05） were prepared by double sintering ceramic technique. The obtained samples were crystallized in single phase structure except the sample with x=0.15. The unit cell volume was found to decrease with increasing AI substitution in orthoferrite. The effective magnetic moment （μeff） and the Curie constant （C） were calculated from the reciprocal of the molar magnetic susceptibility （Z-1） versus absolute temperature plot and found to attain maximum value for the parent sample. The magnetic behavior showed two different magnetic transitions, viz, N6el temperature （TN） and spin reorientation （TsR） transitions. The M-H hysteresis loop of the parent sample took butterfly-shape as a result of different contributions anisotropies. From the magnetic properties measurements, it was obviously found that B-site cation dilution resulted in a drastic decrease in the magnetization. Surprisingly large value of the coercive field was obtained for the undoped sample;Hc=6198.80e. Based on the mentioned results, one can recommend the use of such orthoferrite in magnetic recording media and as pining layer in spin valve for spin- tronic applications.
基金supported by the National Natural Science Foundation of China(No.61274063)
文摘An organic light-emitting diode （OLED） device with high efficiency and brightness is fabricated by inserting CuOJCu dual inorganic buffer layers between indium-tin-oxide （ITO） and hole-transport layer （HTL）. The CuOx/Cu buffer layer limits the operating current density obviously, while the brightness and efficiency are both enhanced greatly. The highest brightness of the optimized device is achieved to be 14 000 cd/m2 at current efficiency of 3 cd/A and bias voltage of 15 V, which is about 50% higher than that of the compared device without CuOJCu buffer layer. The highest efficiency is achieved to be 5.9 cd/A at 11.6 V with 3 400 cd/m^2, which is almost twice as high as that of the compared device.
文摘We present a device for passive unidirectional liquid transport. The capillary channels used are bioinspired by the shape of the spermathecae （receptaculum seminis） of rabbit fleas （Spilopsyllus cuniculi） and rat fleas （Xenopsytla cheopis）. The spermatheca is an organ of female fleas that stores sperm until suitable conditions to lay eggs are found. We translated and multiplied the natural form and function of a spermatheca to create a continuous capillary system from which we designed our microfluidic device based directly on the model from nature. Applying the Young-Laplace equation, we derived a theoretical description of local liquid transport, which enables model-guided design. We arranged the bioinspired capillaries in parallel and engraved them in poly（methyl methacrylate） （PMMA） plates by CO2 laser ablation. The fabricated structures transport soapy water passively （i.e., without external energy input） in the forward direction at velocities of about 1 mm＇s i while halting the liquid fronts completely in the backward direction. The bio- inspired capillary channels are capable of unidirectional liquid transport against gravity. Distance and velocity measurements prove the feasibility of the concept. Unidirectional passive liquid transport might be advantageous in technical surfaces for liquid man- agement, for instance, in biomedical microfluidics, lab-on-chip, lubrication, electronics cooling and in micro-analysis devices.
文摘The development of new materials,having exceptional properties in comparison to existing materials is highly required for bringing advancement in electronic and optoelectronic technologies.Keeping this fact,we investigated structural,electronic,and optical properties of zincblende GaN doped with selected Zn concentrations(6.25%,12.50%,and 18.70%),using the first-principle calculations based on density functional theory with GGA+U.We conducted the entire study using the WIEN2K code.In this study,we calculated various significant parametric quantities such as cohesive energies,formation energies,bulk moduli,and lattice constants along with the study of optical and electronic properties by substituting Ga atoms with Zn atoms in 1×2×2 supercell.The structural stability is confirmed by studying the phonon dispersion curves which suggest that Zn:GaN material is stable against the 6.25%and 18.70%Zn concentrations while for 12.50%,it shows instability.The Hubbard values U=0,2,4,6 eV were added to GGA and the electronic properties were improved with the U=6 eV.Optical absorption was blue shifted while the refractive index and dielectric constant were increased with increasing the Zn concentrations.Electronic properties are enhanced due to the prime contribution of cations(Zn)3ri states.The optical and electronic properties are further discussed in detail in the entire study.
基金This work was partially supported by Slovak grand agency VEGA 2/0145/17,APW-18-0284,Italian flagship NANOMAX,N-CHEM,Ministery o f Education,University and Research(PRIN grant 20173L7W8K).Microscopy was carried out at the SPM@ISMN facility.
文摘The modification of amyloid fibrils cytotoxicity through exogenous nanomaterials is crucial to understand the processes controlling the role of protein aggregation in the related diseases.The influence of nanoparticles on amyloid stability yields great interest due to the small size and high surface area-to-volume ratio of nanoparticles.Various physico-chemical parameters play a role in the interaction of proteins and nanoparticles in solution,thus influencing the disaggregation of preformed fibrils.We have examined the influence of two kinds of metallic nanoparticles on lysozyme amyloid fibrils using a multi-technique approach and focalized their impact on cytotoxicity on human neuroblastoma cells(SH-SY5Y).In particular,fluorescence,infrared and circular dichroism spectroscopies,optical and atomic force microscopy experiments have been carried out;the results are analyzed to rationalize the effects of these complexes on neural cell viability.It is remarkable,that the fibrils in the presence of AuNPs,unlike fibrils alone or with AgNPs,do not generate a significant cytotoxic effect even at high concentration and an amyloid degradation effect is visible.
文摘The paper is concerned with the characteristic features of the dislocation mechanism related to fatigue in ferroelectrics in the process of their repeated switching.In a polarized crystal,dislocations possess a charge the sign of which depends on the orientation of the spontaneous polarization vector relative to the dislocation line.In the process of hysteresis switching,the average force from the applied field acting on a charged dislocation for one period of the hysteresis loop is not equal to zero.Such long-acting force leads to the accumulation of defects near the surface,which can fix a polarization and so partially remove it from the switching process.The proposed mechanism explains the key dependences of the critical number of switching cycles on the field amplitude,frequency and temperature of the sample.
文摘With the use of techniques of SawyerTower and Mertz method regularities of the origin of "fatigue"in thin ferroelectric films of lead titanate and lead zirconate titanate have been investigated in the fields above coercive.We propose a model to explain the experimentally observed switching-dependent fatigue processes by the motion of charged dislocations in an applied external alternating electric field.
基金Supported by National Natural Science Foundation of China(11575103,11747319)the Shanxi Provincial Natural Science Foundation(201701D121005)the Fund for Shanxi "1331 Project" Key Subjects Construction
文摘Rapidity-dependent transverse momentum spectra of negatively charged pions measured at different rapidities in proton-proton collisions at the Super Proton Synchrotron （SPS） at various energies within its Beam Energy Scan （BES） program are investigated by using one- and two-component standard distributions where the chemical potential and spin property of particles are implemented. The rapidity spectra are described by a double- Gaussian distribution. At the stage of kinetic freeze-out, the event patterns are structured by the scatter plots in the three-dimensional subspaces of velocity, momentum and rapidity. The results of the studies of the rapidityindependent transverse mass spectra measured at mid-rapidity in proton-proton collisions are compared with those based on the similar transverse mass spectra measured in the most central beryllium-beryllium, argon-scandium and lead-lead collisions from the SPS at its BES energies.
文摘Methods capable of tuning the properties of van der Waals(vdW)layered materials in a controlled and reversible manner are highly desirable.Interfacial electronic properties of two-dimensional vdW heterostructure consisting of silicene and indium selenide(InSe)have been calculated using density functional theory-based computational code.Furthermore,in order to vary the aforementioned properties,silicene is slid over a InSe layer in the presence of Li intercalation.On intercalation of the heterostructure,the buckling parameter associated with the corrugation of silicene decreases from 0.44A to 0.36A,whereas the InSe structure remains unaffected.Potential energy scans reveal a significant increase in the sliding energy barrier for the case of intercalated heterostructure as compared with the unintercalated heterostructure.The sliding of the silicene encounters the maximum energy barrier of 0.14 eV.Anisotropic analysis shows the noteworthy differences between calculated in-plane and out-of-plane part of dielectric function.A variation of the planar average charge density difference,dipole charge transfer and dipole moment have been discussed to elucidate the usability spectrum of the heterostructure.The employed approach based on intercalation and layer sliding can be effectively utilized for obtaining next-generation multifunctional devices.
基金supported by the National Natural Science Foundation of China(No.61274063)
文摘In this paper,a 64 mm×64 mm matrix polymer solar cell(PSC) was fabricated by air-brush spray deposition.Although the open-circuit voltage(Voc) and the fill factor(FF) both need to be improved,the efficiency of matrix PSCs still reaches about 1.82%,and especially the current density achieves nearly 20 m A/cm2.The results verify that air-brush spray deposition is a suitable method to prepare large area PSC devices,and the process we use in this paper can be easily transplanted to roll-to-roll production.
基金Partly supported by the National Natural Science Foundation of China (11975083, 11947413, 11847317, 11565007, 11735003, 1191101015)the support from the National Natural Science Foundation of China (11775024, 11575023, 11805153)+3 种基金China Scholarship CouncilPartly supported by the Spanish Ministerio de Economia y Competitividad and European FEDER funds (FIS2017-84038-C2-1-PB,FIS2017-84038-C2-2-PB)the Generalitat Valenciana in the program Prometeo II-2014/068the project Severo Ochoa of IFIC, SEV-2014-0398
文摘Using the vector exchange interaction in the local hidden gauge approach,which in the light quark sector generates the chiral Lagrangians and has produced realistic results for Ωc,Ξc,Ξb and the hidden charm pentaquark states,we study the meson-baryon interactions in the coupled channels that lead to the Ξbb and Ωbbb excited states of the molecular type.We obtain seven states of the Ξbb type with energies between 10408 and 10869 MeV,and one Ωbbb state at 15212 MeV.
