检索结果-南通市图书馆

Communications in Theoretical physics 2024年第2期76卷 151-156页

作者： Marjan Zakavi Mohammad Sabaeian Department of physics Faculty of ScienceShahid Chamran University of AhvazIran center for Research on laser and Plasma Shahid Chamran University of AhvazIran

In this study,we successfully extracted the‘knee structure’for non-sequential double ionization(NSDI)in the helium *** achieve this,for the first time,we solved the time-dependent Schrödinger equation in three dimensions for the helium atom,utilizing the shielding charge *** findings corroborate prior observations by Wang et al[Wang and Eberly,***.105,083001(2010)],demonstrating that NSDI occurs within a narrower time window in circular polarization compared to linear *** a result,the yield of linear polarization was higher than that of circular polarization,aligning with the previously reported ***,in the case of circular polarization,the time window further narrows with increasing intensity,attributed to a decrease in the time-of-flight.

关键词： NSDI knee structure TDSE shielding charge helium 3D-TDSE

Research on batch multielement rapid quantitative analysis based on the standard curve-assisted calibration-free laserinduced breakdown spectroscopy method

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2024年第9期26卷 156-164页

作者： Weiwei HAN Duixiong SUN Guoding ZHANG Honglin WANG Kai GUO Yuzhuo ZHANG Haoliang WANG Denghong ZHANG Chenzhong DONG Maogen SU Key Laboratory of Atomic and Molecular physics&Functional Material of Gansu Province College of Physics and Electronic EngineeringNorthwest Normal UniversityLanzhou 730070People’s Republic of China Gansu Digital Herb Testing center Dingxi 743000People’s Republic of China Gansu international Scientific and Technological Cooperation Base of laser Plasma Spectroscopy Lanzhou 730070People’s Republic of China

This study proposes a batch rapid quantitative analysis method for multiple elements by combining the advantages of standard curve(SC)and calibration-free laser-induced breakdown spectroscopy(CF-LIBS)technology to achieve synchronous,rapid,and accurate measurement of elements in a large number of samples,namely,SC-assisted *** alloy standard samples,divided into calibration and test samples,were applied to validate the proposed *** was built based on the characteristic line of Pb and Cr in the calibration sample,and the contents of Pb and Cr in the test sample were calculated with relative errors of 6%and 4%,*** built using Cr with multiple characteristic lines yielded better calculation *** relative contents of ten elements in the test sample were calculated using ***,the SC-assisted CF-LIBS was executed,with the majority of the calculation relative errors falling within the range of 2%-5%.Finally,the Al and Na contents of the Al alloy were *** results demonstrate that it effectively enables the rapid and accurate quantitative analysis of multiple elements after a single-element SC analysis of the tested ***,this quantitative analysis method was successfully applied to soil and Astragalus samples,realizing an accurate calculation of the contents of multiple ***,it is important to advance the LIBS quantitative analysis and its related applications.

关键词： laser-induced breakdown spectroscopy standard curve quantitative analysis multielement

Accurate method based on data filtering for quantitative multi-element analysis of soils using CF-LIBS

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2024年第6期26卷 149-158页

作者：韩伟伟孙对兄张国鼎董光辉崔小娜申金成王浩亮张登红董晨钟苏茂根 Key Laboratory of Atomic and Molecular physics&Functional Material of Gansu Province College of Physics and Electronic EngineeringNorthwest Normal UniversityLanzhou 730070People’s Republic of China Gansu Digital Herb Testing center Dingxi 743000People’s Republic of China Gansu international Scientific and Technological Cooperation Base of laser Plasma Spectroscopy Lanzhou 730070People’s Republic of China

To obtain more stable spectral data for accurate quantitative analysis of multi-element,especially for the large-area in-situ elements detection of soils, we propose a method for a multielement quantitative analysis of soils using calibration-free laser-induced breakdown spectroscopy(CF-LIBS) based on data filtering. In this study, we analyze a standard soil sample doped with two heavy metal elements, Cu and Cd, with a specific focus on the line of Cu I324.75 nm for filtering the experimental data of multiple sample sets. Pre-and post-data filtering,the relative standard deviation for Cu decreased from 30% to 10%, The limits of detection(LOD)values for Cu and Cd decreased by 5% and 4%, respectively. Through CF-LIBS, a quantitative analysis was conducted to determine the relative content of elements in soils. Using Cu as a reference, the concentration of Cd was accurately calculated. The results show that post-data filtering, the average relative error of the Cd decreases from 11% to 5%, indicating the effectiveness of data filtering in improving the accuracy of quantitative analysis. Moreover, the content of Si, Fe and other elements can be accurately calculated using this method. To further correct the calculation, the results for Cd was used to provide a more precise calculation. This approach is of great importance for the large-area in-situ heavy metals and trace elements detection in soil, as well as for rapid and accurate quantitative analysis.

关键词： laser-induced breakdown spectroscopy soil data filtering quantitative analysis multielement

In situ calibrated angle between the quantization axis and the propagating direction of the light field for trapping neutral atoms

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2024年第2期33卷 318-323页

作者：郭瑞军何晓东盛诚王坤鹏许鹏刘敏王谨孙晓红曾勇詹明生 Henan Key Laboratory of laser and Optoelectronic Information National Center for International Joint Research of Electronic Materials and SystemsSchool of Electrical and Information EngineeringZhengzhou UniversityZhengzhou 450001China State Key Laboratory of Magnetic Resonance and Atomic and Molecular physics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China

The recently developed magic-intensity trapping technique of neutral atoms efficiently mitigates the detrimental effect of light shifts on atomic qubits and substantially enhances the coherence time. This technique relies on applying a bias magnetic field precisely parallel to the wave vector of a circularly polarized trapping laser field. However, due to the presence of the vector light shift experienced by the trapped atoms, it is challenging to precisely define a parallel magnetic field, especially at a low bias magnetic field strength, for the magic-intensity trapping of85Rb qubits. In this work, we present a method to calibrate the angle between the bias magnetic field and the trapping laser field with the compensating magnetic fields in the other two directions orthogonal to the bias magnetic field direction. Experimentally, with a constantdepth trap and a fixed bias magnetic field, we measure the respective resonant frequencies of the atomic qubits in a linearly polarized trap and a circularly polarized one via the conventional microwave Rabi spectra with different compensating magnetic fields and obtain the corresponding total magnetic fields via the respective resonant frequencies using the Breit–Rabi formula. With known total magnetic fields, the angle is a function of the other two compensating magnetic ***, the projection value of the angle on either of the directions orthogonal to the bias magnetic field direction can be reduced to 0(4)° by applying specific compensating magnetic fields. The measurement error is mainly attributed to the fluctuation of atomic temperature. Moreover, it also demonstrates that, even for a small angle, the effect is strong enough to cause large decoherence of Rabi oscillation in a magic-intensity trap. Although the compensation method demonstrated here is explored for the magic-intensity trapping technique, it can be applied to a variety of similar precision measurements with trapped neutral atoms.

关键词： quantization axis trapping laser angle compensating magnetic fields

Domain wall network:A dual solution for gravitational waves and Hubble tension?

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2024年第11期67卷 39-46页

作者： Ligong Bian Shuailiang Ge Changhong Li Jing Shu Junchao Zong Department of physics and Chongqing Key Laboratory for Strongly Coupled physics Chongqing UniversityChongqing 401331China center for High Energy physics Peking UniversityBeijing 100871China School of physics and State Key Laboratory of Nuclear physics and Technology Peking UniversityBeijing 100871China Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan ProvinceSchool of Physics and AstronomyYunnan UniversityKunming 650091China Beijing laser Acceleration Innovation center Beijing 101400China Department of physics Nanjing UniversityNanjing 210093China CAS Key Laboratory of Theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China

We explore the possibility that domain wall networks generate the stochastic gravitational wave background(SGWB) observed as a strong common power-law process in the Data Release-2 of Parkes Pulsar Timing Array. We find that a broad range of parameters, specifically wall tension around σ_(DW)^(29-414 TeV)^(3) and wall-decay temperature within T_(d) ~ 20-257 MeV, can explain this phenomenon at a 68% credible level. Meanwhile, the same parameters could ease the Hubble tension if particles from these domain wall networks decay into dark radiation. We establish a direct analytical relationship, ΩGW(f_(p), T_(0))h^(2)~ Ω_(rad)h^(2)(Ω_νΩN_(eff))^(2),to illustrate this coincidence, underlining its importance in the underlying physics and potential applicability to a wider range of models and data. Conversely, if the common power-law process is not attributed to domain wall networks, our findings impose tight limits on the wall tension and decay temperature.

关键词： domain wall gravitational waves Hubble tension

Stable,intense supercontinuum light generation at 1 kHz by electric field assisted femtosecond laser filamentation in air

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第2期13卷 354-365页

作者： Yaoxiang Liu Fukang Yin Tie-Jun Wang Yuxin Leng Ruxin Li Zhizhan Xu See Leang Chin State Key Laboratory of High Field laser physics Shanghai Institute of Optics and Fine Mechanics and CAS Center for Excellence in Ultra-intense Laser ScienceChinese Academy of SciencesShanghaiChina center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Centre d’Optique Photonique et Laser(COPL)and Département de physiquede génie physique et d’optiqueUniversitéLavalQuébecQuébecCanada

Supercontinuum(SC)light source has advanced ultrafast laser spectroscopy in condensed matter science,biology,physics,and *** to the frequently used photonic crystal fibers and bulk materials,femtosecond laser filamentation in gases is damage-immune for supercontinuum generation.A bottleneck problem is the strong jitters from filament induced self-heating at kHz repetition rate *** demonstrated stable kHz supercontinuum generation directly in air with multiple mJ level pulse *** was achieved by applying an external DC electric field to the air plasma *** pointing jitters of the 1 kHz air filament induced SC light were reduced by more than 2 *** stabilized high repetition rate laser filament offers the opportunity for stable intense SC generation and its applications in air.

关键词： intense repetition light

Pulse repetition rate effect on the plasma inside femtosecond laser filament in air

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2024年第1期22卷 135-140页

作者：尹富康王铁军刘尧香龙娟魏迎霞朱斌周凯南冷雨欣 State Key Laboratory of High Field laser physics Shanghai Institute of Optics and Fine Mechanics and CAS Center for Excellence in Ultra-intense Laser ScienceChinese Academy of SciencesShanghai 201800China center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China laser Fusion Research center and Science&Technology on Plasma physics Laboratory China Academy of Engineering PhysicsMianyang 621999China

The characteristics of plasmas play an important role in femtosecond laser filament-based *** analysis is used to experimentally investigate the plasma density and its temperature of the air filament under different pulse repetition *** our experiments,the measured average plasma density of the filament is 1.54×10^(17)cm^(-3)and the temperature of the plasma is about 5100 K under 100 Hz pulse repetition *** plasma density decreases to1.43×10^(17)cm^(-3)and the temperature increases to 6230 K as the pulse repetition rate increases to 1000 *** experimental observation agrees with the numerical simulation by solving the nonlinear Schr?dinger equations with repetition rate related“low density hole”correction.

关键词： femtosecond laser filamentation cumulative effects electron density

Polarization control of above-threshold ionization spectrum in elliptically polarized two-color laser fields

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2024年第4期33卷 136-144页

作者：金发成杨慧慧宋晓红李飞杜玲玲薛红杰魏丽敏白悦刘浩翔王兵兵杨玮枫 faculty of Science Xi'an Aeronautical InstituteXi'an 710077China School of physics and Optoelectronic Engineering Hainan UniversityHaikou 570288China center for Theoretical physics Hainan UniversityHaikou 570288China Laboratory of Optical physics Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing 100190China College of Science Shantou UniversityShantou 515063China University of Chinese Academy of Sciences Beijing 100049China

We study the above-threshold ionization(ATI)process of atoms exposed to fundamental and high-frequency lasers with arbitrary ellipticity by applying the frequency-domain *** is found that the angular-resolved ATI spectrum is sensitive to ellipticities of two lasers and emitted angles of the *** for the photon energy of the highfrequency laser more than atomic ionization potential,the width of plateau tends to a constant with increasing ellipticity of fundamental field,the dip structure disappears with increasing ellipticity of the high-frequency *** the help of the quantum channel analysis,it is shown that the angular distribution depends mainly on the ellipticity of high-frequency field in the case that its frequency is ***,one can see that the maximal and minimal energies in quantum numerical results are in good agreement with the classical *** investigation may provide theoretical support for experimental research on polarization control of ionization in elliptically polarized two-color laser fields.

关键词： above-threshold ionization two-color laser polarization control

In-situ study of the microstructure evolution during tension of a Mg-Y-Zn-Al alloy processed by rapidly solidified ribbon consolidation technique

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第5期12卷 2024-2040页

作者： Jeno Gubicza Kristián Máthis Péter Nagy Péter Jenei Zoltán Hegedus Andrea Farkas Jozef Vesely Shin-ichi Inoue Daria Drozdenko Yoshihito Kawamura Department of Materials physics Faculty of ScienceEotvos Loránd UniversityPázmány P.sétány 1/ABudapest H-1117Hungary Department of physics of Materials Faculty of Mathematics and PhysicsCharles UniversityKe Karlovu 512116 Praha 2Czech Republic Deutsches Elektronen-Synchrotron DESY Notkestr.85Hamburg 22603Germany Magnesium Research center Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan

Mg-Y-Zn-Al alloys processed by rapidly solidified ribbon consolidation(RSRC)technique exhibit an exceptional mechanical performance indicating promising application *** material has a bimodal microstructure consisting of fine recrystallized and coarse non-recrystallized grains with solute-rich stacking faults forming cluster arranged layers(CALs)and nanoplates(CANaPs),or complete long period stacking ordered(LPSO)*** order to reveal the deformation mechanisms,in-situ synchrotron X-ray diffraction line profile analysis was employed for a detailed study of the dislocation arrangement created during tension in Mg-0.9%Zn-2.05%Y-0.15%Al(at%)*** uncovering the effect of the initial microstructure on the mechanical performance,additional samples were obtained by annealing of the as-consolidated specimen at 300 and 400℃ for 2 *** heat treatment at 300℃ had no significant effect on the initial microstructure,its evolution during tension and,thus,the overall deformation behavior under tensile *** the other hand,annealing at 400℃ resulted in a significant increase of the recrystallized grains fraction and a decrease of the dislocation density,leading to only minor degradation of the mechanical *** maximum dislocation density at the failure of the samples corresponding to the plastic strain of 10-25% was estimated to be about 16-20×10^(14)m^(-2).The diffraction profile analysis indicated that most dislocations formed during tension were of non-basal and pyramidal types,what was also in agreement with the Schmid factor values revealed independently from orientation *** was also shown that the dislocation-induced Taylor hardening was much lower below the plastic strain of 3% than above this value,which was explained by a model of the interaction between prismatic dislocations and CANaPs/LPSO plates.

关键词： Mg-Zn-Y-Al alloy Long period stacking ordered(LPSO)phase Cluster arranged nanoplates(CANaPs) Annealing Tension Dislocation density Hardening

Validation of the TOPAS Monte-Carlo Code of the Off-Field Dose of a 6 MV Synergy Linac

在线全文

学校读者我要写书评

暂无评论

Journal of Biosciences and Medicines 2024年第7期12卷 38-54页

作者： Kodjo Joel Fabrice N’Guessan Ibrahima Sakho Bogbé D. L. H. Gogon Department of physics and Chemistry Faculty of Sciences and Technology Iba Der Thiam University of This This Senegal international Cancer center of Dakar Dakar Senegal Department of physics Faculty of Sciences and Technology Flix Houphouet Boigny University of Abidjan Abidjan Cte dIvoire

The risk of radiation-induced second cancer and the late tissue loss due to Off-field doses in radiotherapy remain a serious concern. Monte Carlo (MC) simulation is currently one of the most accurate methods for calculating these doses. MC simulation model based on the Particle Simulation Tool (TOPAS) has been developed to simulate the off-field dose of an Elekta Synergy linear accelerator (Linac) emitting 6 MV photons. Measurements were taken in a water phantom using an ionization chamber to validate this model. The Percentage Depth Dose (PDD) at the depth of 0.0, 5.0, 10.0 and 15.0 cm from the beam axis for a 10 × 10 cm2 field size was measured and simulated. Off-field dose profiles at the depth of 1.5 (dmax), 5.0 and 10.0 cm for field sizes of 5 × 5, 10 × 10, 15 × 15, and 20 × 20 cm2 respectively were measured and simulated. Comparison of measured and simulated off-field dose values showed a good agreement. The average gamma passing rate of the PDDs and profiles curves for off-field doses were 87.5% and 98.11% respectively. The local dose difference based on the PDD curve between the measured and simulated was less than 6.0 % for all locations. For all field size considered in this study, the average difference between profile curves for off-field dose measured and simulated was 9.1%. PDDs and Profiles curves for off-field dose simulation uncertainties were less than 2.0% and 1.0% respectively. TOPAS-MC simulation model developed is a good representation of our 6 MV Linac Elekta Synergy for assessing off-field dose, which would be the primary cause of some secondary cancers.

关键词： Radiotherapy Off-Field Dose Secondary Cancer TOPAS-MC Simulation Dosimetry