The oxidation resistance behavior of SmCo(2:17)-type high-temperature magnets modified with Ni-Cr two-layer coating was studied. The study depicts the mass gain kinetics and magnetic properties of uncoated and NiCr-mo...The oxidation resistance behavior of SmCo(2:17)-type high-temperature magnets modified with Ni-Cr two-layer coating was studied. The study depicts the mass gain kinetics and magnetic properties of uncoated and NiCr-modified magnets oxidized at high temperature(500 ℃) in air for 200 h. The oxidation test results illustrate that the mass gain of uncoated magnet is6.95 mg·cm^(-2) which is more than that(0.08 mg·cm^(-2)) of coated magnet after 200 h. For the magnetic properties concerned, there is a great loss for uncoated magnet, while for coated magnet, magnetic properties do not change much. The study of uncoated magnet through X-ray diffraction(XRD) and electron probe microanalysis(EPMA) shows that the invasion of oxygen at high temperature leads to the loss of magnetic properties by changing the microstructure of magnet.展开更多
We present a design of an acoustic levitator consisting of three pairs of opposite transducer arrays.Three orthogonal standing waves create a large number of acoustic traps at which the particles are levitated in mid-...We present a design of an acoustic levitator consisting of three pairs of opposite transducer arrays.Three orthogonal standing waves create a large number of acoustic traps at which the particles are levitated in mid-air.By changing the phase difference of transducer arrays,three-dimensional manipulation of particles is successfully realized.Moreover,the relationship between the translation of particles and the phase difference is experimentally investigated,and the result is in agreement with the theoretical calculation.This design can expand the application of acoustic levitation in many fields,such as biomedicine,ultrasonic motor and new materials processing.展开更多
This paper describes the standardization of the proton-induced x-ray emission（PIXE） technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard refe...This paper describes the standardization of the proton-induced x-ray emission（PIXE） technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials（SRMs） were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 Me V obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.展开更多
Attosecond transient absorption(ATA)has been developed as an all-optical technique for probing electron dynamics in matter.Here we present a scheme that can modify the laserinduced state and the corresponding ATA spec...Attosecond transient absorption(ATA)has been developed as an all-optical technique for probing electron dynamics in matter.Here we present a scheme that can modify the laserinduced state and the corresponding ATA spectrum via excitation by a pair of XUV attosecond pulses and by a time-delayed mid-infrared(MIR)laser probe.Different from the scheme of the electronic excitation by a single XUV attosecond pulse,the application of a pair of XUV pulses provides extra degrees of freedom,such as the time delay and the intensity ratio between two XUV pulses,which make it possible to adjust the pump process,resulting in the modification of the ATA spectrum.We show that by varying the time delay between the two XUV pulses,the population of the dark state and the ATA spectrum of the laser-induced state have periodic modulations.We also demonstrate that the peak of the ATA spectrum of the laser-induced state appears at a fixed time delay between the XUV pair and the MIR laser when the intensity ratio is large,and it changes with the time delay when the intensity ratio is small,which can be related to either one of two peaks in the population of the dark state.展开更多
Fabric is a kind of turbid materials with strong light scattering, to which the Kubelka-Munk theory can be applied to describe it optical behavior. In this paper, the light absorption coefficients of dyestuff in fabri...Fabric is a kind of turbid materials with strong light scattering, to which the Kubelka-Munk theory can be applied to describe it optical behavior. In this paper, the light absorption coefficients of dyestuff in fabrics are obtained by test and calculation through a special method proposed by the authors. Then the optical behaviours of dyestuff in fabric are studied. Results show that, the absorption coefficient of dye in fabric is non-scalable and exponential to dye concentration in fabric which is totally different from that of the dye in transparent media like water.展开更多
The 0.8 Me V copper ( Cu) ion beam irradiation-induced effects on structural, morphological and optical properties of tin dioxide nanowires (SnO_(2)NWs) are investigated. The samples are irradiated at three different ...The 0.8 Me V copper ( Cu) ion beam irradiation-induced effects on structural, morphological and optical properties of tin dioxide nanowires (SnO_(2)NWs) are investigated. The samples are irradiated at three different doses 5 × 10^12 ions/cm^(2), 1 ×10^(13) ions/cm^(2) and 5 × 10^(13) ions/em^(2) at room temperature. The XRD analysis shows that the tetragonal phase of SnO_(2)NWs remains stable after Cu ion irradiation, but with increasing irradiation dose level the crystal size increases due to ion beam induced coalescence of NWs. The FTIR spectra of pristine SnO_(2)NWs exhibit the chemical composition of SnO_(2)while the Cn-O bond is also observed in the FTIR spectra after Cu ion beam irradiation. The presence of Cu impurity in SnO_(2)is further confirmed by calculating the stopping range of Cu ions by using TRM/SRIM code. Optical properties of SnO_(2)NWs are studied before and after Cu ion irradiation. Band gap analysis reveMs that the band gap of irradiated samples is found to decrease compared with the pristine sample. Therefore, ion beam irradiation is a promising technology for nanoengineering and band gap tailoring.展开更多
Magnetic hysteresis and compensation behavior of a mixed spin-（1, 3/2） Ising model on a square lattice are investigated in the framework of effective field theory based on a probability distribution technique. The e...Magnetic hysteresis and compensation behavior of a mixed spin-（1, 3/2） Ising model on a square lattice are investigated in the framework of effective field theory based on a probability distribution technique. The effect of random crystal field, ferromagnetic and ferrimagnetic exchange interaction on hysteresis loops and compensation phenomenon are discussed. A number of characteristic phenomena have been reported such as the observation of triple hysteresis loops at low temperatures and for negative values of random crystal field. Critical and double compensation temperatures have been also found. The obtained results are also compared to some previous works.展开更多
In 2021,the Belle collaboration reported the first observation of a new structure in theψ(2S)γfinal state produced in the two-photon fusion process.In the hadronic molecule picture,this new structure can be associat...In 2021,the Belle collaboration reported the first observation of a new structure in theψ(2S)γfinal state produced in the two-photon fusion process.In the hadronic molecule picture,this new structure can be associatedwith the shallow isoscalar D*D* bound state and as such is an excellent candidate for the spin-2 partner of the X(3872)with the quantum numbers J^(PC)=2^(++)conventionally named X_(2).展开更多
Composite structure materials were potential sensing elements for magnetic sensors due to Giant magnetoimpedance(GMI) effect. Two kinds of composite wires with different magnetic/non-magnetic structures were fabricate...Composite structure materials were potential sensing elements for magnetic sensors due to Giant magnetoimpedance(GMI) effect. Two kinds of composite wires with different magnetic/non-magnetic structures were fabricated by using electroless deposition methods and the magnetoimpedance properties were investigated. The maximum GMI ratio of 114% was acquired at 60 MHz in the composite wires with a ferromagnetic core, whereas, 116% of maximum GMI ratio was found in the composite wires with a conductive core at low frequency of 600 k Hz. These results exhibit that the GMI ratio reaches the maximum when magnetoresistance ratio ?R/R and magnetoinductance ratio ?X/X make the comparative contributions to the total magnetoimpedance(MI). The obvious GMI effect obtained in the composite wires with conductive core frequency may provide a candidate for applications in magnetic sensors, especially at low frequencies.展开更多
The increased demand of electronic devices promotes the development of advanced and more efficient energy storage devices, such as batteries. Lithium-ion batteries (LIBs) are the most studied battery systems due to th...The increased demand of electronic devices promotes the development of advanced and more efficient energy storage devices, such as batteries. Lithium-ion batteries (LIBs) are the most studied battery systems due to their high performance. Among the different battery components, the separator allows the control of lithium ion diffusion between the electrodes. To overcome some drawbacks of liquid electrolytes, including safety and environmental issues, solid polymer electrolytes (SPEs) are being developed. In this work, a UV photocurable polyurethane acrylate (PUA) resin has been blended with lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) up to 30 wt% LiTFSI content to reach a maximum ionic conductivity of 0.0032 mS/cm at room temperature and 0.09 mS/cm at 100 ℃. Those values allowed applying the developed materials as photocurable SPE in Swagelok type Li/C-LiFePO_(4) half-cells, reaching a battery discharge capacity value of 139 mAh.g^(−1) at C/30 rate. Those results, together with the theoretical studies of the discharge capacity at different C-rates and temperatures for batteries with LiTFSI/PUA SPE demonstrate the suitability of the developed photocurable SPE for LIB applications.展开更多
Over the last few years, lots of attentions have been given to the demand response(DR) for the frequency control. DR can be incorporated with traditional frequency control method and enhance the stability of the syste...Over the last few years, lots of attentions have been given to the demand response(DR) for the frequency control. DR can be incorporated with traditional frequency control method and enhance the stability of the system. In this paper, the frequency control strategy of DR for a multiarea power system is specially designed. In order to quickly stabilize the frequency of different areas, the tie-line power is adopted as the additional input signal of DR. To get the optimal parameters of the control system, the frequency control problem is formulated as a multi-objective optimization problem, and the parameters such as the integral gains of secondary frequency control, the frequency bias parameters, and coefficients of DR are optimized. Numerical results verify the effectiveness of the proposed method.展开更多
Vertically aligned p-silicon nanowire （SiNW） arrays have been extensively investigated in recent years as promising photocathodes for solar-driven hydrogen evolution. However, the fabrication of SiNW photocathodes w...Vertically aligned p-silicon nanowire （SiNW） arrays have been extensively investigated in recent years as promising photocathodes for solar-driven hydrogen evolution. However, the fabrication of SiNW photocathodes with both high photoelectrocatalytic activity and long-term operational stability using a simple and affordable approach is a challenging task. Herein, we report conformal and continuous deposition of a di-cobalt phosphide （C02P） layer on lithography- patterned highly ordered SiNW arrays via a cost-effective drop-casting method followed by a low-temperature phosphorization treatment. The as-deposited C02P layer consists of crystalline nanoparticles and has an intimate contact with SiNWs, forming a well-defined SiNW@Co2P core/shell nanostructure. The conformal and continuous Co2P layer functions as a highly efficient catalyst capable of substantially improving the photoelectrocatalytic activity for the hydrogen evolution reaction （HER） and effectively passivates the SiNWs to protect them from photo-oxidation, thus prolonging the lifetime of the electrode. As a consequence, the SiNW@Co2P photocathode with an optimized C02P layer thickness exhibits a high photocurrent density of -21.9 mA·cm^-2 at 0 V versus reversible hydrogen electrode and excellent operational stability up to 20 h for solar-driven hydrogen evolution, outperforming many nanostructured silicon photocathodes reported in the literature. The combination of passivation and catalytic functions in a single continuous layer represents a promising strategy for designing high-performance semiconductor photoelectrodes for use in solar-driven water splitting, which may simplify fabrication procedures and potentially reduce production costs.展开更多
Purpose:To measure axial and off-axis refraction patterns in myopic eyes with spectacle lenses correction and lens free emmetropes in young healthy subjects at different target distances from 2.00 m(0.50 D)to 0.20 m(5...Purpose:To measure axial and off-axis refraction patterns in myopic eyes with spectacle lenses correction and lens free emmetropes in young healthy subjects at different target distances from 2.00 m(0.50 D)to 0.20 m(5.00 D)in terms of sphere,astigmatism,and spherical equivalent refraction.Methods:Refraction was measured at the center,20 and 40 degrees from the line of sight both nasally and temporally in 15 emmetropic and 25 myopic young healthy subjects with an open field,binocular,infrared autorefractor(Grand Seiko WAM-5500,Hiroshima,Japan).Fixation target was a Maltese cross set at 2.00,0.50,0.33 and 0.20 m from the corneal plane.Changes in off-axis refraction with accommodation level were normalized with respect to distance axial values and compared between myopic eyes with spectacle lenses correction and lens free emmetropes.Results:Off-axis refraction in myopic eyes with spectacle lenses correction was significantly more myopic in the temporal retina compared to lens free emmetropes except for the closest target distance.Relative off-axis refractive error changed significantly with accommodation when compared to axial refraction particularly in the myopic group.This change in the negative direction was due to changes in the spherical component of refraction that became more myopic relative to the center at the 0.20 m distance as the J0 component of astigmatism was significantly reduced in both emmetropes and myopes for the closest target.Conclusion:Accommodation to very near targets(up to 0.20 m)makes the off-axis refraction of myopes wearing their spectacle correction similar to that of lens free emmetropes.A significant reduction in off-axis astigmatism was also observed for the 0.20 m distance.展开更多
Background:To characterize the axial and off-axis refraction across four meridians of the retina in myopic eyes before and after Orthokeratology(OK)and LASIK surgery.Methods:Sixty right eyes with a spherical equivalen...Background:To characterize the axial and off-axis refraction across four meridians of the retina in myopic eyes before and after Orthokeratology(OK)and LASIK surgery.Methods:Sixty right eyes with a spherical equivalent(M)between−0.75 to−5.25 D(cylinder<−1.00 D)underwent LASIK(n=26)or OK(n=34)to treat myopia.Axial and off-axis refraction were measured with an open-field autorefractometer before and after stabilized treatments.Off-axis measurements were obtained for the horizontal(35°nasal and temporal retina)and vertical(15°superior and inferior retina)meridians,and for two oblique directions(45–225°and 135–315°)up to 20°of eccentricity.The refractive profile was addressed as relative peripheral refractive error(RPRE).Results:OK and LASIK post-treatment results showed an increase of myopic relative refraction at several eccentric locations.At the four meridians evaluated,the M component of the pre-treatment RPRE values was not statistically different(p>0.05)from the post-treatment RPRE within 30°and 20°of the central visual field after LASIK and OK,respectively.These results demonstrated that the treatment zone warrants an optimal central field of vision.Conclusions:The present study gives an overview of RPRE after refractive corneal reshaping treatments(OK and LASIK)across vertical,horizontal and two oblique meridians together.This allows a 3D representation of RPRE at the retina and shows that the myopic shift induced by both treatments is more relevant in horizontal directions.展开更多
Background:To identify biometric and implantable collamer lens(ICL)-related risk factors associated with suboptimal postoperative vault in eyes implanted with phakic ICL.Methods:This study reports a retrospective case...Background:To identify biometric and implantable collamer lens(ICL)-related risk factors associated with suboptimal postoperative vault in eyes implanted with phakic ICL.Methods:This study reports a retrospective case series of the first operated eye in 360 patients implanted with myopic spherical or toric ICL.Preoperatively,white-to-white(WTW),central keratometry(Kc)and central corneal thickness(CCT)were measured using the Pentacam.Anterior-segment optical coherence tomography(AS-OCT,Visante)was applied preoperatively for measuring the horizontal anterior-chamber angle-to-angle distance(ATA),internal anterior chamber depth(ACD),crystalline lens rise(CLR),anterior-chamber angle(ACA)and postoperatively the vault.Eyes were divided into three vault groups:low(LVG:≤250μm),optimal(OVG:>250 and<1000μm)and high(HVG:≥1000μm).Multinomial logistic regression(MLR)was used to find the sub-optimal vault predictors.Results:MLR showed that CLR,ICL size minus the ATA(ICL size-ATA),age,ICL spherical equivalent(ICLSE)and ICL size as contributing factors for sub-optimal vaults(pseudo-R2=0.40).Increased CLR(OR:1.01,CI:1.00-1.01)and less myopic ICLSE(OR:1.22,CI:1.07-1.40)were risk factors for low vaults.Larger ICL size-ATA(OR:41.29,CI:10.57-161.22)and the 13.7mm ICL(OR:7.08,CI:3.16-15.89)were risk factors for high vaults,whereas less myopic ICLSE(OR:0.85,CI:0.76-0.95)and older age(OR:0.92,CI:0.88-0.98)were protective factors.Conclusion:High CLR and low ICLSE were the major risk factors in eyes presenting low vaults.In the opposite direction,ICL size-ATA was the major contributor for high vaults.This relationship was more critical in higher myopic ICLSE,younger eyes and when 13.7mm ICL were used.The findings show that factors influencing the vault have differentiated weight of influence depending on the type of vault(low,optimal or high).展开更多
Based on a combination of X-ray diffraction, electrical transports, magnetic susceptibility, specific heat, and pressure-effect measurements, we report the results of experiments on a series of BiS_2-based Sr_(1-x)Pr_...Based on a combination of X-ray diffraction, electrical transports, magnetic susceptibility, specific heat, and pressure-effect measurements, we report the results of experiments on a series of BiS_2-based Sr_(1-x)Pr_xFBiS_2 superconductors with the maximum Tcof 2.7 K for x=0.5 and at ambient pressure. Superconductivity appears only for 0.4≤x≤0.7 whereas the normal-state resistivity shows the semiconducting-like behaviors. The magnetic susceptibility χ(T) displays the low superconducting shielding volume fractions and C(T) shows no distinguishable anomaly near Tc, which suggests a filamentary superconductivity in the Pr-doped polycrystalline samples. By varying doping concentrations, an electronic phase diagram is established. Upon applying pressure on the optimally doped Sr_(0.5)Pr_(0.5)FBiS_2 system, Tcis abruptly enhanced, reaches 8.5 K at the critical pressure of P_c=1.5 GPa, and increases slightly to 9.7 K at 2.5 GPa. Accompanied by the enhancement of superconductivity from the low-to the high-Tc phases, the normal state undergoes a semiconductor-to-metal transition when under pressure. This scenario may be linked to enhanced overlap of the Bi-6 p and S-p orbitals, which contributes to the enhanced superconductivity above Pc. The pressuretemperature phase diagram for Sr_(0.5)Pr_(0.5)FBiS_2 is also presented.展开更多
Dear Editor,Recently,Alióand co-works published a study[1]comparing the clinical optical image quality of patients following implantation with different intraocular lenses(IOLs),based on the analysis of the wavef...Dear Editor,Recently,Alióand co-works published a study[1]comparing the clinical optical image quality of patients following implantation with different intraocular lenses(IOLs),based on the analysis of the wavefront measured with a pyramidal wavefront sensor-based aberrometer.A set of nine groups of patients was evaluated,including patients implanted with two diffractive trifocals.展开更多
Background To identify biometric and implantable collamer lens(ICL)-related risk factors associated with sub-optimal postoperative vault in eyes implanted with phakic ICL.Methods This study reports a retrospective cas...Background To identify biometric and implantable collamer lens(ICL)-related risk factors associated with sub-optimal postoperative vault in eyes implanted with phakic ICL.Methods This study reports a retrospective case series of the first operated eye in 360 patients implanted with myopic spherical or toric ICL.Preoperatively,white-to-white(WTW),central keratometry(Kc)and central corneal thickness(CCT)were measured using the Pentacam.Anterior-segment optical coherence tomography(AS-OCT,Visante)was applied preoperatively for measuring the horizontal anterior-chamber angle-to-angle distance(ATA),internal anterior chamber depth(ACD),crystalline lens rise(CLR),anterior-chamber angle(ACA)and postoperatively the vault.Eyes were divided into three vault groups:low(LVG:≤250μm),optimal(OVG:>250 and<1000μm)and high(HVG:≥1000μm).Multinomial logistic regression(MLR)was used to find the sub-optimal vault predictors.Results MLR showed that CLR,ICL size minus the ATA(ICL size-ATA),age,ICL spherical equivalent(ICLSE)and ICL size as contributing factors for sub-optimal vaults(pseudo-R2=0.40).Increased CLR(OR:1.01,CI:1.00–1.01)and less myopic ICLSE(OR:1.22,CI:1.07–1.40)were risk factors for low vaults.Larger ICL size-ATA(OR:41.29,CI:10.57–161.22)and the 13.7 mm ICL(OR:7.08,CI:3.16–15.89)were risk factors for high vaults,whereas less myopic ICLSE(OR:0.85,CI:0.76–0.95)and older age(OR:0.92,CI:0.88–0.98)were protective factors.Conclusion High CLR and low ICLSE were the major risk factors in eyes presenting low vaults.In the opposite direction,ICL size-ATA was the major contributor for high vaults.This relationship was more critical in higher myopic ICLSE,younger eyes and when 13.7 mm ICL were used.The findings show that factors influencing the vault have differentiated weight of influence depending on the type of vault(low,optimal or high).展开更多
In this first-principles investigation,we explore the polymorphic features of pseudo-cubic alloys,focusing on the impact of mixing organic and inorganic cations on their structural and electronic properties,configurat...In this first-principles investigation,we explore the polymorphic features of pseudo-cubic alloys,focusing on the impact of mixing organic and inorganic cations on their structural and electronic properties,configurational disorder,and thermodynamic stability.展开更多
基金financially supported by the National Science Foundation of China(No.51471016)the Natural Science Foundation of Beijing(No.2151002)
文摘The oxidation resistance behavior of SmCo(2:17)-type high-temperature magnets modified with Ni-Cr two-layer coating was studied. The study depicts the mass gain kinetics and magnetic properties of uncoated and NiCr-modified magnets oxidized at high temperature(500 ℃) in air for 200 h. The oxidation test results illustrate that the mass gain of uncoated magnet is6.95 mg·cm^(-2) which is more than that(0.08 mg·cm^(-2)) of coated magnet after 200 h. For the magnetic properties concerned, there is a great loss for uncoated magnet, while for coated magnet, magnetic properties do not change much. The study of uncoated magnet through X-ray diffraction(XRD) and electron probe microanalysis(EPMA) shows that the invasion of oxygen at high temperature leads to the loss of magnetic properties by changing the microstructure of magnet.
基金Supported by the Beijing College Students’Innovation and Entrepreneurship Training Program under Grant No BJ17040
文摘We present a design of an acoustic levitator consisting of three pairs of opposite transducer arrays.Three orthogonal standing waves create a large number of acoustic traps at which the particles are levitated in mid-air.By changing the phase difference of transducer arrays,three-dimensional manipulation of particles is successfully realized.Moreover,the relationship between the translation of particles and the phase difference is experimentally investigated,and the result is in agreement with the theoretical calculation.This design can expand the application of acoustic levitation in many fields,such as biomedicine,ultrasonic motor and new materials processing.
文摘This paper describes the standardization of the proton-induced x-ray emission（PIXE） technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials（SRMs） were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 Me V obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.
基金supported by the National Natural Science Foundation of China(Grant Nos.91950102 and 11834004)the Natural Science Foundation of Jiangsu Province(Grant No.BK20220925)the Funding of Nanjing University of Science and Technology(NJUST)(Grant No.TSXK2022D005)
文摘Attosecond transient absorption(ATA)has been developed as an all-optical technique for probing electron dynamics in matter.Here we present a scheme that can modify the laserinduced state and the corresponding ATA spectrum via excitation by a pair of XUV attosecond pulses and by a time-delayed mid-infrared(MIR)laser probe.Different from the scheme of the electronic excitation by a single XUV attosecond pulse,the application of a pair of XUV pulses provides extra degrees of freedom,such as the time delay and the intensity ratio between two XUV pulses,which make it possible to adjust the pump process,resulting in the modification of the ATA spectrum.We show that by varying the time delay between the two XUV pulses,the population of the dark state and the ATA spectrum of the laser-induced state have periodic modulations.We also demonstrate that the peak of the ATA spectrum of the laser-induced state appears at a fixed time delay between the XUV pair and the MIR laser when the intensity ratio is large,and it changes with the time delay when the intensity ratio is small,which can be related to either one of two peaks in the population of the dark state.
基金China Postdoctoral Science Foundation (No.20070410662)
文摘Fabric is a kind of turbid materials with strong light scattering, to which the Kubelka-Munk theory can be applied to describe it optical behavior. In this paper, the light absorption coefficients of dyestuff in fabrics are obtained by test and calculation through a special method proposed by the authors. Then the optical behaviours of dyestuff in fabric are studied. Results show that, the absorption coefficient of dye in fabric is non-scalable and exponential to dye concentration in fabric which is totally different from that of the dye in transparent media like water.
基金Supported by the Department of Physics,the University of AJKHigh Tech.Centralized Instrumentation Lab,the University of AJK,Pakistanthe Experimental Physics Division,and the National Center for Physics,Islamabad Pakistan
文摘The 0.8 Me V copper ( Cu) ion beam irradiation-induced effects on structural, morphological and optical properties of tin dioxide nanowires (SnO_(2)NWs) are investigated. The samples are irradiated at three different doses 5 × 10^12 ions/cm^(2), 1 ×10^(13) ions/cm^(2) and 5 × 10^(13) ions/em^(2) at room temperature. The XRD analysis shows that the tetragonal phase of SnO_(2)NWs remains stable after Cu ion irradiation, but with increasing irradiation dose level the crystal size increases due to ion beam induced coalescence of NWs. The FTIR spectra of pristine SnO_(2)NWs exhibit the chemical composition of SnO_(2)while the Cn-O bond is also observed in the FTIR spectra after Cu ion beam irradiation. The presence of Cu impurity in SnO_(2)is further confirmed by calculating the stopping range of Cu ions by using TRM/SRIM code. Optical properties of SnO_(2)NWs are studied before and after Cu ion irradiation. Band gap analysis reveMs that the band gap of irradiated samples is found to decrease compared with the pristine sample. Therefore, ion beam irradiation is a promising technology for nanoengineering and band gap tailoring.
文摘Magnetic hysteresis and compensation behavior of a mixed spin-（1, 3/2） Ising model on a square lattice are investigated in the framework of effective field theory based on a probability distribution technique. The effect of random crystal field, ferromagnetic and ferrimagnetic exchange interaction on hysteresis loops and compensation phenomenon are discussed. A number of characteristic phenomena have been reported such as the observation of triple hysteresis loops at low temperatures and for negative values of random crystal field. Critical and double compensation temperatures have been also found. The obtained results are also compared to some previous works.
基金supported in part by the National Natural Science Foundation of China(Grant Nos.12070131001,12125507,11835015,and 12047503)the Deutsche Forschungsgemeinschaft(DFG)through the funds provided to the Sino-German Collaborative Research Center TRR110“Symmetries and the Emergence of Structure in QCD”(Project-ID 196253076)+4 种基金the Chinese Academy of Sciences(CAS)(Grant Nos.YSBR-101 and XDB34030000)the EU STRONG-2020 project under the program H2020-INFRAIA-2018-1(Grant No.824093)the Generalitat valenciana(GVA)for the project with ref.CIDEGENT/2019/015supported by the Slovenian Research Agency(research core Funding No.P1-0035)by CAS President’s International Fellowship Initiative(PIFI)(Grant No.2024PVA0004)。
文摘In 2021,the Belle collaboration reported the first observation of a new structure in theψ(2S)γfinal state produced in the two-photon fusion process.In the hadronic molecule picture,this new structure can be associatedwith the shallow isoscalar D*D* bound state and as such is an excellent candidate for the spin-2 partner of the X(3872)with the quantum numbers J^(PC)=2^(++)conventionally named X_(2).
基金Shanghai Automotive Science and Technology Development Foundation (SAISTDF/12-06)East China Normal University Program (78210142, 78210183)Shanghai Ocean University Program (A-2600-10-0054, B-5406-12-0012)
文摘Composite structure materials were potential sensing elements for magnetic sensors due to Giant magnetoimpedance(GMI) effect. Two kinds of composite wires with different magnetic/non-magnetic structures were fabricated by using electroless deposition methods and the magnetoimpedance properties were investigated. The maximum GMI ratio of 114% was acquired at 60 MHz in the composite wires with a ferromagnetic core, whereas, 116% of maximum GMI ratio was found in the composite wires with a conductive core at low frequency of 600 k Hz. These results exhibit that the GMI ratio reaches the maximum when magnetoresistance ratio ?R/R and magnetoinductance ratio ?X/X make the comparative contributions to the total magnetoimpedance(MI). The obvious GMI effect obtained in the composite wires with conductive core frequency may provide a candidate for applications in magnetic sensors, especially at low frequencies.
基金Work supported by the Portuguese national funds(PIDDAC),through the Portuguese Foundation for Science and Technology(FCT)and FCT/MCTES:projects UID/FIS/04650/2020.UID/QUI/0686/2020,UID/CTM/50025/2020,UIDB/05549/2020,PTDC/FIS-MAC/28157/2017Grants SFRH/BD/140842/2018(J.C.B.),CEECIND/00833/2017(R.G.)and SFRH/BPD/112547/2015(C.M.C.).Financial support from the Basque Government Industry Departments under the ELKARTEK and HAZITEK programs is also acknowledged.
文摘The increased demand of electronic devices promotes the development of advanced and more efficient energy storage devices, such as batteries. Lithium-ion batteries (LIBs) are the most studied battery systems due to their high performance. Among the different battery components, the separator allows the control of lithium ion diffusion between the electrodes. To overcome some drawbacks of liquid electrolytes, including safety and environmental issues, solid polymer electrolytes (SPEs) are being developed. In this work, a UV photocurable polyurethane acrylate (PUA) resin has been blended with lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) up to 30 wt% LiTFSI content to reach a maximum ionic conductivity of 0.0032 mS/cm at room temperature and 0.09 mS/cm at 100 ℃. Those values allowed applying the developed materials as photocurable SPE in Swagelok type Li/C-LiFePO_(4) half-cells, reaching a battery discharge capacity value of 139 mAh.g^(−1) at C/30 rate. Those results, together with the theoretical studies of the discharge capacity at different C-rates and temperatures for batteries with LiTFSI/PUA SPE demonstrate the suitability of the developed photocurable SPE for LIB applications.
基金supported in part by the University Science Research Project of Jiangsu Province (No. 16KJB470009)
文摘Over the last few years, lots of attentions have been given to the demand response(DR) for the frequency control. DR can be incorporated with traditional frequency control method and enhance the stability of the system. In this paper, the frequency control strategy of DR for a multiarea power system is specially designed. In order to quickly stabilize the frequency of different areas, the tie-line power is adopted as the additional input signal of DR. To get the optimal parameters of the control system, the frequency control problem is formulated as a multi-objective optimization problem, and the parameters such as the integral gains of secondary frequency control, the frequency bias parameters, and coefficients of DR are optimized. Numerical results verify the effectiveness of the proposed method.
文摘Vertically aligned p-silicon nanowire （SiNW） arrays have been extensively investigated in recent years as promising photocathodes for solar-driven hydrogen evolution. However, the fabrication of SiNW photocathodes with both high photoelectrocatalytic activity and long-term operational stability using a simple and affordable approach is a challenging task. Herein, we report conformal and continuous deposition of a di-cobalt phosphide （C02P） layer on lithography- patterned highly ordered SiNW arrays via a cost-effective drop-casting method followed by a low-temperature phosphorization treatment. The as-deposited C02P layer consists of crystalline nanoparticles and has an intimate contact with SiNWs, forming a well-defined SiNW@Co2P core/shell nanostructure. The conformal and continuous Co2P layer functions as a highly efficient catalyst capable of substantially improving the photoelectrocatalytic activity for the hydrogen evolution reaction （HER） and effectively passivates the SiNWs to protect them from photo-oxidation, thus prolonging the lifetime of the electrode. As a consequence, the SiNW@Co2P photocathode with an optimized C02P layer thickness exhibits a high photocurrent density of -21.9 mA·cm^-2 at 0 V versus reversible hydrogen electrode and excellent operational stability up to 20 h for solar-driven hydrogen evolution, outperforming many nanostructured silicon photocathodes reported in the literature. The combination of passivation and catalytic functions in a single continuous layer represents a promising strategy for designing high-performance semiconductor photoelectrodes for use in solar-driven water splitting, which may simplify fabrication procedures and potentially reduce production costs.
基金supported by Strategic Project PEST-C/FIS/UI607/2011 from the Science and Technology Foundation of Portuguese Ministry of Science and Higher Education.
文摘Purpose:To measure axial and off-axis refraction patterns in myopic eyes with spectacle lenses correction and lens free emmetropes in young healthy subjects at different target distances from 2.00 m(0.50 D)to 0.20 m(5.00 D)in terms of sphere,astigmatism,and spherical equivalent refraction.Methods:Refraction was measured at the center,20 and 40 degrees from the line of sight both nasally and temporally in 15 emmetropic and 25 myopic young healthy subjects with an open field,binocular,infrared autorefractor(Grand Seiko WAM-5500,Hiroshima,Japan).Fixation target was a Maltese cross set at 2.00,0.50,0.33 and 0.20 m from the corneal plane.Changes in off-axis refraction with accommodation level were normalized with respect to distance axial values and compared between myopic eyes with spectacle lenses correction and lens free emmetropes.Results:Off-axis refraction in myopic eyes with spectacle lenses correction was significantly more myopic in the temporal retina compared to lens free emmetropes except for the closest target distance.Relative off-axis refractive error changed significantly with accommodation when compared to axial refraction particularly in the myopic group.This change in the negative direction was due to changes in the spherical component of refraction that became more myopic relative to the center at the 0.20 m distance as the J0 component of astigmatism was significantly reduced in both emmetropes and myopes for the closest target.Conclusion:Accommodation to very near targets(up to 0.20 m)makes the off-axis refraction of myopes wearing their spectacle correction similar to that of lens free emmetropes.A significant reduction in off-axis astigmatism was also observed for the 0.20 m distance.
基金Supported in part by a grant to AQ(#SFRH/BD/61768/2009)projects PTDC/SAU-BEB/098391/2008,PTDC/SAU-BEB/098392/2008 and the Strategic Project PEST-C/FIS/UI607/2011 from the Science and Technology Foundation of Portuguese Ministry of Science and Higher Education.
文摘Background:To characterize the axial and off-axis refraction across four meridians of the retina in myopic eyes before and after Orthokeratology(OK)and LASIK surgery.Methods:Sixty right eyes with a spherical equivalent(M)between−0.75 to−5.25 D(cylinder<−1.00 D)underwent LASIK(n=26)or OK(n=34)to treat myopia.Axial and off-axis refraction were measured with an open-field autorefractometer before and after stabilized treatments.Off-axis measurements were obtained for the horizontal(35°nasal and temporal retina)and vertical(15°superior and inferior retina)meridians,and for two oblique directions(45–225°and 135–315°)up to 20°of eccentricity.The refractive profile was addressed as relative peripheral refractive error(RPRE).Results:OK and LASIK post-treatment results showed an increase of myopic relative refraction at several eccentric locations.At the four meridians evaluated,the M component of the pre-treatment RPRE values was not statistically different(p>0.05)from the post-treatment RPRE within 30°and 20°of the central visual field after LASIK and OK,respectively.These results demonstrated that the treatment zone warrants an optimal central field of vision.Conclusions:The present study gives an overview of RPRE after refractive corneal reshaping treatments(OK and LASIK)across vertical,horizontal and two oblique meridians together.This allows a 3D representation of RPRE at the retina and shows that the myopic shift induced by both treatments is more relevant in horizontal directions.
文摘Background:To identify biometric and implantable collamer lens(ICL)-related risk factors associated with suboptimal postoperative vault in eyes implanted with phakic ICL.Methods:This study reports a retrospective case series of the first operated eye in 360 patients implanted with myopic spherical or toric ICL.Preoperatively,white-to-white(WTW),central keratometry(Kc)and central corneal thickness(CCT)were measured using the Pentacam.Anterior-segment optical coherence tomography(AS-OCT,Visante)was applied preoperatively for measuring the horizontal anterior-chamber angle-to-angle distance(ATA),internal anterior chamber depth(ACD),crystalline lens rise(CLR),anterior-chamber angle(ACA)and postoperatively the vault.Eyes were divided into three vault groups:low(LVG:≤250μm),optimal(OVG:>250 and<1000μm)and high(HVG:≥1000μm).Multinomial logistic regression(MLR)was used to find the sub-optimal vault predictors.Results:MLR showed that CLR,ICL size minus the ATA(ICL size-ATA),age,ICL spherical equivalent(ICLSE)and ICL size as contributing factors for sub-optimal vaults(pseudo-R2=0.40).Increased CLR(OR:1.01,CI:1.00-1.01)and less myopic ICLSE(OR:1.22,CI:1.07-1.40)were risk factors for low vaults.Larger ICL size-ATA(OR:41.29,CI:10.57-161.22)and the 13.7mm ICL(OR:7.08,CI:3.16-15.89)were risk factors for high vaults,whereas less myopic ICLSE(OR:0.85,CI:0.76-0.95)and older age(OR:0.92,CI:0.88-0.98)were protective factors.Conclusion:High CLR and low ICLSE were the major risk factors in eyes presenting low vaults.In the opposite direction,ICL size-ATA was the major contributor for high vaults.This relationship was more critical in higher myopic ICLSE,younger eyes and when 13.7mm ICL were used.The findings show that factors influencing the vault have differentiated weight of influence depending on the type of vault(low,optimal or high).
基金supported by the National Natural Science Foundation of China(Grant Nos.11474082,61401136,and 61376094)the Natural Science Foundation of Zhejiang Province(Grant No.LY18F010019)+3 种基金the QianJiang Talents Program of Zhejiang Provincesupported by an open program from Wuhan National High Magnetic Field Center(Grant No.2016KF03)supported by the General Program of Natural Science Foundation of Jiangsu Province of China(Grant No.BK20171440)the support from the 1000Youth Talents Plan of China
文摘Based on a combination of X-ray diffraction, electrical transports, magnetic susceptibility, specific heat, and pressure-effect measurements, we report the results of experiments on a series of BiS_2-based Sr_(1-x)Pr_xFBiS_2 superconductors with the maximum Tcof 2.7 K for x=0.5 and at ambient pressure. Superconductivity appears only for 0.4≤x≤0.7 whereas the normal-state resistivity shows the semiconducting-like behaviors. The magnetic susceptibility χ(T) displays the low superconducting shielding volume fractions and C(T) shows no distinguishable anomaly near Tc, which suggests a filamentary superconductivity in the Pr-doped polycrystalline samples. By varying doping concentrations, an electronic phase diagram is established. Upon applying pressure on the optimally doped Sr_(0.5)Pr_(0.5)FBiS_2 system, Tcis abruptly enhanced, reaches 8.5 K at the critical pressure of P_c=1.5 GPa, and increases slightly to 9.7 K at 2.5 GPa. Accompanied by the enhancement of superconductivity from the low-to the high-Tc phases, the normal state undergoes a semiconductor-to-metal transition when under pressure. This scenario may be linked to enhanced overlap of the Bi-6 p and S-p orbitals, which contributes to the enhanced superconductivity above Pc. The pressuretemperature phase diagram for Sr_(0.5)Pr_(0.5)FBiS_2 is also presented.
文摘Dear Editor,Recently,Alióand co-works published a study[1]comparing the clinical optical image quality of patients following implantation with different intraocular lenses(IOLs),based on the analysis of the wavefront measured with a pyramidal wavefront sensor-based aberrometer.A set of nine groups of patients was evaluated,including patients implanted with two diffractive trifocals.
文摘Background To identify biometric and implantable collamer lens(ICL)-related risk factors associated with sub-optimal postoperative vault in eyes implanted with phakic ICL.Methods This study reports a retrospective case series of the first operated eye in 360 patients implanted with myopic spherical or toric ICL.Preoperatively,white-to-white(WTW),central keratometry(Kc)and central corneal thickness(CCT)were measured using the Pentacam.Anterior-segment optical coherence tomography(AS-OCT,Visante)was applied preoperatively for measuring the horizontal anterior-chamber angle-to-angle distance(ATA),internal anterior chamber depth(ACD),crystalline lens rise(CLR),anterior-chamber angle(ACA)and postoperatively the vault.Eyes were divided into three vault groups:low(LVG:≤250μm),optimal(OVG:>250 and<1000μm)and high(HVG:≥1000μm).Multinomial logistic regression(MLR)was used to find the sub-optimal vault predictors.Results MLR showed that CLR,ICL size minus the ATA(ICL size-ATA),age,ICL spherical equivalent(ICLSE)and ICL size as contributing factors for sub-optimal vaults(pseudo-R2=0.40).Increased CLR(OR:1.01,CI:1.00–1.01)and less myopic ICLSE(OR:1.22,CI:1.07–1.40)were risk factors for low vaults.Larger ICL size-ATA(OR:41.29,CI:10.57–161.22)and the 13.7 mm ICL(OR:7.08,CI:3.16–15.89)were risk factors for high vaults,whereas less myopic ICLSE(OR:0.85,CI:0.76–0.95)and older age(OR:0.92,CI:0.88–0.98)were protective factors.Conclusion High CLR and low ICLSE were the major risk factors in eyes presenting low vaults.In the opposite direction,ICL size-ATA was the major contributor for high vaults.This relationship was more critical in higher myopic ICLSE,younger eyes and when 13.7 mm ICL were used.The findings show that factors influencing the vault have differentiated weight of influence depending on the type of vault(low,optimal or high).
基金The authors thank the Atos and Yemoja Computer at CIMATEC SENAI(Salvador-BA)and“Laboratório Central de Processamento de Alto Desempenho”(LCPAD)financed by FINEP through CT-INFRA/UFPR projects in Brazil to support the electronic structure calculationsPart of this work was performed on the HoreKa supercomputer funded by the Ministry of Science,Research and the Arts Baden-Württemberg and by the Federal Ministry of Education and Research+6 种基金L.O.A.thanks the Coordination for Improvement of Higher Level Education−CAPES(finance Code 001)for fundingM.J.P.thanks the National Council for Scientific and Technological Development−CNPq(grant number 307345/2021-1)W.W.and C.R.C.R.thank the German Federal Ministry of Education and Research(BMBF)for financial support of the project Innovation-Platform MaterialDigital(www.materialdigital.de)through project funding FKZ number 13XP5094AA.C.D.thanks the financial support from the National Council for Scientific and Technological Development(CNPq,408144/2022-0)Federal District Research Support Foundation(FAPDF,grant 00193-00001817/2023-43)also the computational resources from“Centro Nacional de Processamento de Alto Desempenho em São Paulo”(CENAPAD-SP,UNICAMP/FINEP-MCTI project)for resources into 897 project,Lobo Carneiro HPC(NACAD)at the Federal University of Rio de Janeiro(UFRJ)into 133 projectsupport by the KITPublication Fund of the Karlsruhe Institute of Technology.
文摘In this first-principles investigation,we explore the polymorphic features of pseudo-cubic alloys,focusing on the impact of mixing organic and inorganic cations on their structural and electronic properties,configurational disorder,and thermodynamic stability.
