Subjects: Library Science，Information Science >> Information Science submitted time 2024-04-24
Abstract： Abstract: Objective This paper reviews the relevant progress of semantic novelty research at home and abroad, and summarizes the relevant technologies to provide reference for the subsequent research. Coverage Using retrieval methods such as Novelty of the literature , semantic novelty , literature novelty , semantic novelty and literature evaluation , after reading and sorting, this paper traced the source of representative relevant theoretical researches, and finally selected 70 literatures for review. Methods This paper summarizes the relevant researches on semantic novelty at home and abroad, and analyzes the development status and future trend of semantic novelty evaluation in scientific and technological literature by focusing on the definition of novelty, evaluation indexes of novelty and different evaluation methods. Results Semantic novelty evaluation has gradually attracted widespread attention from the academic community. There have been related studies on semantic content mining and evaluation, but no unified measurement index has yet been formed. Limitations The existing literature novelty is mostly evaluated from external features, while the number of literatures directly focusing on semantic novelty is small, which has limitations in supporting the review. Conclusions The evaluation of semantic novelty of scientific and technological literature is based on the novelty of content. Quantitative research has become the mainstream research method, but the calculation method of evaluation index needs to be clarified, and the development direction of novelty evaluation should be combined with qualitative and quantitative methods to achieve a scientific and reasonable comprehensive evaluation.
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-04-19
Abstract： In order to meet the demand for elementary particle detection and analysis in high-energy physics experiments, modern pixel detector increasingly tends to pursue the performance requirements of low power consumption, high resolution, and high readout efficiency.This paper describes a silicon pixel detector digital-analogue hybrid readout chip named IMPix-N1. The pixel array consists of 16 rows × 16 columns of pixel units, each with an area of 100 μm × 100 μm, and the pixel array part is controlled by a 1-row × 8-column pixel unit as a superpixel, which has a common logic circuit. The chip has a pixel configuration mode and three pixel address readout modes of operation, which realises the measurement, storage and readout of the time, energy and position information of the hitting particles. The time-to-digital conversion circuit (TDC) can simultaneously measure and record the arrival time TOA and the over-threshold time TOT of the particles, with a time measurement accuracy of 5 ns. The IMPix-N1 is suitable for particle detection experiments requiring high temporal and spatial resolution as well as fast data acquisition capabilities.The chip as a whole is designed using the digital-on-top methodology in TSMC 180nm process. The design is simulated to verify the digital circuit of the pixel unit, the super pixel control circuit and the peripheral digital circuits, and the before and after simulation results are consistent and meet the design requirements.
Subjects: Astronomy >> History of Astronomy Subjects: Astronomy >> Astronomical Instruments and Techniques submitted time 2024-04-10
Abstract： Ancient China recorded a wealth of astronomical observations, notably distinguished by the inclusion of empirical measurements of stellar observations. However, determining the precise observational epochs for these datasets poses a formidable challenge. This study employs the Generalized Hough Transform methodology to analyze two distinct sets of observational data originating from the Song and Yuan dynasties, allowing accurate estimation of the epochs of these stellar observations. This research introduces a novel and systematic approach, offering a scholarly perspective for the analysis of additional datasets within the domain of ancient astronomical catalogs in future investigations.
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology submitted time 2024-04-08
Xiaoli Li
Mengxin Xu
Yuan He
Zehua Liang
Shengxue Zhang
Chunlong Li
Lubei Liu
Qitong Huang
Tong Liu
Jiyu Wang
Guochang Liu
Zhi Wang
Tiancai Jiang
Pinan Xiang
Zhijun Wang
Yangyang Yang
Abstract： For the superconducting linac section of the Chinese Accelerator Driven Transmutation Research facility (CiADS) operating in continuous wave (CW) mode, the effect of cavity detuning caused by fluctuations of liquid helium pressure is an important factors for stable operation of low β cavities. Aiming at the phenomenon of unstable operation of half-wave superconducting resonators affected by helium pressure fluctuations, and taking the half-wave superconducting resonator with a frequency of 162.5 MHz and an optimal beta of 0.19(HWR019) applied in CiADS superconducting linac section as an example, the fluctuation of liquid helium pressure and the frequency variation law of the cavity was simulated with the method of numerical simulation. By calculating and analyzing the relationship between the contact area of liquid helium in the cavity, the wall thickness of the cavity, the shape of the liquid helium cooling channel, and the helium pressure sensitivity coefficient (KPress) of the cavity, the goal of reducing the (KPress) value of the HWR019 superconducting cavity to close to 0 was achieved, which effectively ensures the stable operation of the superconducting cavity in CiADS. At the same time, by conducting thermodynamic calculations on the cavity, corresponding enhanced heat transfer schemes were provided, effectively reducing the maximum temperature of the superconducting cavity during operation. The analysis and optimization methods also have reference significance for the same type of low β superconducting cavities.
Subjects: Nuclear Science and Technology >> Engineering Technology of Fission Reactor submitted time 2024-04-07
Abstract： Background : For high-fidelity simulations of fluid dynamics in molten salt reactor, even though a supercomputer is able to suppress the period of each simulation, the consequent expense is still prohibitively costly. A possible way to overcome this limitation is the use of Reduced Order Modelling (ROM) techniques. Purpose : Evaluating the accuracy of the ROM methods for reconstructing the velocity and pressure fields. Methods : Two ROM methods based on the Proper Orthogonal Decomposition (POD) with both Galerkin projection, namely FV-ROM (ROM based on Finite Volume approximation ) and SUP-ROM (ROM with supremizer stabilization ), are established for fluid dynamics of molten salt reactor. Then, both methods are tested on the unsteady cases of liquid-fueled molten salt reactor (LFMSR). Results : The FV-ROM demonstrates notable advantages in both velocity prediction and computational efficiency. For laminar and turbulent transient simulations, the average velocity L2 relative errors are less than 0.5% and 0.6%, respectively, with acceleration ratios of approximately 1500 and 1000 times for single time steps. Conversely, the SUP-ROM scheme demonstrates significant prowess in pressure prediction, achieving remarkably low pressure average L2 relative errors of 0.20% and 0.38% for laminar and turbulent transient scenario, respectively. Conclusions : The integration of the SUP-ROM and FV-ROM for fluid dynamics computations of molten salt reactor could significantly enhances computational efficiency and ensure reliability and accuracy of transient simulation.
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-03-20
Fu Shengwei
Long Jinbiao
Zhan Meiqiang
Lu Chengui
Guo Yufei
Yang Junjie
Zhang Zhe
Yu Yuhong
Lu Fenhua
Liu Tuoqi
Li Zhiyao
Xu Yingfeng
Sun Zhiyu
Yang Herun
Abstract： The properties of working gases in gas detectors,such as the average ionization energy,Fano factor,and drift velocity,have a significant impact on the preliminary simulation,parameter design,and trajectory reconstruction of the detectors.SeF6,as the target working gas in domestic neutrinoless double beta decay experiments,has unknown parameters that need to be investigated.To study the relevant parameters of this gas,a measurement scheme was designed and the accuracy and reliability of the experimental plan were tested using Ar/CH4=90/10(P10) as the working gas.In the experiment,the average ionization energy of P10 was measured using a grid ionization chamber with an 𝛼 source,yielding a value of 27.10±0.04 eV,and the Fano factor was determined to be 0.175±0.001 when the energy resolution reached 0.91% after subtracting noise through calibration electronics.Additionally,the drift velocity was measured using a 266 nm laser and a time projection chamber,and the results were consistent with the Garfield++ simulation results.The experimental results indicate the feasibility of the measurement scheme and demonstrate high reliability of
the measurement results.This provides a solid foundation for further research on the properties of SeF6.
Subjects: Physics >> Nuclear Physics Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-02-27
LUFenhua
TANG Shuwen
FU Shengwei
YAN Duo
MA Peng
YANG Haibo
YU Yuhong
ZHANG Xueheng
WANG Shitao
ZHANG Yongjie
FANG Fang
LIU Tuoqi
XU Yingfeng
LI Zhiyao
LIU Xiangman
WEI Xiaobao
SUN Zhiyu
Abstract： The high-intensity heavy-ion accelerator facility (HIAF) under construction is equipped with an advanced radioactive beam line HFRS, which will provide a new opportunity for the research of high-energy radionuclide beam physics in China.The characteristic of HFRS is high intensity, This puts forward very strict requirements for particle recognition energy loss detector.The traditional energy loss detector generally adopts the analog plug-in technology route of preamplifier, main amplifier and ADC for signal processing.This scheme has some problems, such as slow electronic response, poor flexibility and difficulty in dealing with serious pulse pile-up at high count rate. We propose a new applicable to high count rate energy loss detector scheme.The signal of the energy loss detector is initially amplified by the fast charge sensitive preamplifier, and Then the waveform is directly collected by waveform digitizer and then processed by digital algorithm.And use the Multiple Sampling Ionization Chamber (MUSIC) of secondary beam line of lanzhou RIBLL2 for the radioactive source and beam test.Using the 3 components 𝛼 source test, using digital shaping algorithm processing for acquisition of waveform, energy resolution (FWHM) of up to 1.31%.In RIBLL2 provide 300 MeV/u of 56Fe beam test, uses the time constant of 𝜏f = 2 𝜇𝑠 of fast charge sensitive preamplifier on the count rate is close to 1 MHz is still not occurred pulse pile-up obviously.
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics Subjects: Physics >> Nuclear Physics submitted time 2024-02-26
LIUTuoQi
TANGShuWen
SUN Yu
YU Yuhong
FANG Fang
WANG Shitao
ZHANG Xueheng
SUN Zhiyu
LU Fenhua
FU Shengwei
Li Zhiyao
WEI Xiaobao
XU Yingfeng
Abstract： Cosmic rays are used for the calibration of the Veto detector at ETF in HIRFL-CSR of the Cooling Storage
Ring of Heavy Ion Research Facility in Lanzhou(HIRFL-CSR). The work is divided into two parts: position calibration
and time calibration. The hit positions of particles are obtained by position calibration and an uniform standard of the
measurement of particle hit time in the Veto detector is built through time calibration. The information of position and
time of particles serves as important criteria for eliminating changed particle events that hit the neutron wall detector,
providing support for the realization of the physical objectives of the neutron wall detector. A 2.53 cm position resolution
and a 1.09 ns time resolution have been achieved in this paper.
Subjects: Physics >> Nuclear Physics Subjects: Physics >> Atomic and Molecular Physics submitted time 2024-02-22
Abstract： The state-selective single-electron capture process in the collision of N+ ions with He at an energy of 0.64 keV/u has been experimentally studied by the reaction microscopy with a two-fold coincident method, and the state-selective cross-sections and angular distributions of an electron captured into different quantum states of the projectile ions have been obtained. The experimental results show that: the ground state projectile N+(3P) captures a 1𝑠 electron from the He target mainly to the 2𝑝 shell, and the contribution to the higher shells can also be observed; the metastable N+(5S) captures a 1𝑠 electron from the He target mainly to the 2𝑠 shell, with almost no contribution to higher shells. The experimental results are interpreted qualitatively using the potential energy curves of the NHe+ quasimolecular ion, but the reaction window predictions of the molecular Coulomb over-barrier model differ significantly from the experiments. During the capture of the target electron into the 2𝑠 orbital by the metastable projectile N+(5S), a clear oscillatory structure appears in the angular differential cross-section, which is likely to result from Demkov-type transitions.
Subjects: Nuclear Science and Technology >> Nuclear Science and Technology submitted time 2024-02-04
Abstract： CAFE-2 is a superconducting linear accelerator built by the Institute of Modern Physics of the Chinese Academy of Sciences (IMP) in 2021 to carry out research on new superheavy nuclides synthesis, chemical properties of superheavy elements, and the structure and properties of superheavy nuclei. The synchronized timing trigger system is an important subsystem of CAFE-2 and plays a key role in the operation of CAFE-2. The CAFE-2 main synchronization timing system adopts the classical event-based timing system. At the same time, in order to meet the needs of different operation timing and synchronization triggering of CAFE-2 in both accelerator commissioning and terminal operation modes, the synchronization trigger signal of the rotating target modulation is coupled with the main timing CW(Continuous-wave) trigger signal in the terminal operation mode through the design of the coupling circuit and interlocking logic. The problem of different trigger signal sources for CAFE-2 in accelerator commissioning and terminal operation modes is solved. This paper introduces the structure of CAFE-2 synchronous timing trigger system, and describes the principle and scheme of CAFE-2 synchronous timing trigger system in different operation modes.
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-01-22
Abstract： Based on a UMC 55 nm CMOS process, this paper implements a 10 GHz high-performance charge pump phase-locked loop with high-speed output and low power consumption, which can provide a high-frequency differential clock for the data transmission system in particle physics experiments. A dual-branch charge pump with an operational amplifier and dummy MOSFETs is designed to reduce the influence of non-ideal factors on the circuit. A high-speed, low-power 64-divider circuit is designed to convert the 10 GHz differential clock output by the phase-locked loop into a 156.25MHz single-ended clock. An LC voltage-controlled oscillator is designed with a complementary cross-coupled structure, which enables fast start-up with low phase noise. The simulation results show that under the typical process corner, the phase noise of the VCO at 1 MHz frequency offset is -104.14 dBc/Hz. The PLL lock time is about 500ns, the power consumption is 22.34mW, and the peak-to-peak jitter is 6.59ps.
Subjects: Astronomy >> Astrophysics submitted time 2024-01-22
Abstract： Deconvolution of radio astronomy images is a key data processing technique. Its main goal is to remove the effects introduced by the instrument from the observed sky images to recover the original sky images.However, radio interferometer arrays employ sparse interferometric arrays, whose imaging principles differfrom those of optical telescopes. If the sampling points in the UV space are not sufficiently dense, this will lead to insufficient high-resolution information during image reconstruction. Traditional radio astronomy image reconstruction algorithms fail to fundamentally solve the problem of UV space undersampling. This paper adopts the compressed sensing theoretical framework, combines prior knowledge of the sparsity of radio astronomy images, and studies a new radio astronomy image deconvolution algorithm, namely the IUWT-CS-based radio interferometric image reconstruction algorithm. This algorithm transforms the dirty image deconvolution process into a convex optimization problem to find the global minimum. To evaluate the reconstruction performance of this algorithm, we used the OSKAR radio astronomy simulation software package to simulate low SKA1 observations and performed deconvolution processing on the extended radio sources obtained. Experimental results show that, compared with the HOGBOM-CLEAN, MS-CLEAN,and IUWT-FISTA methods, the IUWT-CS method significantly improves the reconstruction quality of radio images and achieves finer denoising and restoration effects.
Peer Review Status:
Awaiting Review
Subjects: Nuclear Science and Technology >> Nuclear Science and Technology submitted time 2024-01-04
Abstract： In proton and heavy ion radiotherapy, the relative stopping power of each voxel point obtained by CT scan for patient is the key to accurately calculate the dose distribution in the body using treatment planning system. In this study, a tissue equivalent phantom was scanned twice by setting different tube voltages for a conventional CT scanner. The relative electron density and effective atomic number of the phantom were calculated by the CT values derived from the two-set images, and then the relative stopping power of the phantom was calculated. The results showed that the relative stopping power of the tissue equivalent phantom acquired with the two-set CT values was better than that based on the conventional single set of CT images. Thus, the method established in this study might play an important role in further improving the dose calculation accuracy in the treatment planning of proton and heavy ion radiotherapy.
Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2023-12-14
Abstract： The space charge effect is the core problem of high intensity proton accelerator, especially at injection and initial acceleration stages. Using the phase space painting with optimized process, will effectively eliminate the influence of space charge effect on injection and acceleration efficiency, and emittance increase. Transverse phase space painting methods can be divided into correlated painting and anti-correlated painting. In this paper, firstly, the transverse phase space paintings for the high intensity proton synchrotron are discussed in detail, including different painting methods and different implementation methods. Secondly, based on the injection system of the China Spallation Neutron Source, the beam injection process and anti-correlated painting design scheme are studied in detail. The reasons for the reduction of the actual vertical painting range and the influence of edge focusing effects of the bump magnets on the painting and beam dynamics are deeply explored. In addition, the method to perform the correlated painting based on the mechanical structure of the anti-correlated painting scheme and its key role in realizing the CSNS design goal are briefly introduced. Finally, according to the requirement of switching between different painting methods online in future accelerators, a new injection scheme that can realize correlated and anti-correlated painting simultaneously has been proposed. The new painting injection scheme has been demonstrated, simulated and optimized in detail.
Subjects: Physics >> Nuclear Physics submitted time 2023-12-11
Abstract： Based on the self-consistent RBUU transport theory, the isospin-dependent in-medium $N Delta rightarrow N Delta$ cross section is investigated. It is found that the isospin effect has obvious influence on the effective mass, as well as the total $N Delta$ elastic scattering cross section in different density regions. With the increase of baryon density, the effective mass splitting between different isospin states of baryons increases gradually. Under the joint effect of density-dependent baryon effective mass splitting, coupling constant, as well as Born terms such as $ sigma- delta$, $ sigma- rho$, $ omega- delta$, $ omega- rho$, the elastic cross-sections of sub-channels with different isospin states exhibit different density-dependent behaviors. The total cross-section has an obvious reduction effect of medium in the low-energy region, and the medium effect is weakened in the high-energy region.
Subjects: Physics >> Atomic and Molecular Physics submitted time 2023-12-03
Abstract： Experimental and theoretical research on X-ray emissions following charge exchange between slow highly charged ions and atomic Hydrogen supply vital atomic data in the study of diagnosing and simulating plasmas in non-equilibrium astrophysical environment. In the present paper, employing the semiclassical multi-channel Landau-Zener (MCLZ) method, we calculated the total cross-section of bare and hydrogenic C, N, O ions charge exchange with hydrogen atoms, and compared it with previously reported experimental results. In C5 + H collision, theoretically calculated cross-sections have large differences with experimental cross-sections. We also compared state-selective cross-sections calculated by classical MCLZ and quantum-mechanical molecular orbital close-coupling(QMOCC) methods in the solar wind ion velocity (or energy) range. For capture to n = 3 shell, MCLZ calculated state-selective cross-section increase with collision energy increasing; For capture to n = 4 shell, MCLZ calculated state-selective cross-section decrease with collision energy increasing; It is lower than two magnitudes as QMOCC method calculated cross-section. Finally, using the Kronos program package developed in the astrophysical field, we calculated the X-ray emission spectrum, line ratio, and hardness ratio of charge exchange of 1000 eV/u O8 by means of recommended cross-section by Janev, and contrast with the MCLZ method calculated results. We consider that the MCLZ calculation has a large uncertainty, which could affect the accuracy of the astrophysical environment simulation. It is required for developing a more accurate full quantum theory.
Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2023-11-29
Abstract： The accelerator vacuum monitoring system is an important subsystem in the accelerator control system, which plays an important role in maintaining the normal operation of the accelerator. The design, development and development process of traditional large-scale control systems are highly dependent on physical entities, and the functional testing and performance verification of the whole system are all concentrated in the late stage of the project, resulting in a long development cycle of the control system, higher risks, and a tight time for late field debugging. To this end, industrial virtual debugging and virtual machine technologies were introduced to build a full-level virtual simulation debugging platform for the accelerator vacuum monitoring system. In the early stage of development, parallel collaborative development, full-level virtual debugging and logic rehearsal of the accelerator air monitoring system began to be carried out. Finally, the debugging results were applied to the site through on-site configuration, significantly shortening the time of on-site debugging. Reduce equipment loss and commissioning risk, improve project implementation efficiency and engineering design reliability.
Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2023-11-07
Abstract： EPICS, a software tool extensively used in large-scale scientific experiments such as particle accelerators. Depending on the scale of the facility, the number of EPICS PV can range from tens of thousands to millions. The ability to swiftly retrieve information related to EPICS PV can notably enhance the operational efficiency and maintenance of particle accelerators. To address this requirement, we designed and developed the EPICS PV information platform. This platform provides a unified user interface that supports the querying of PV lists, real-time statuses, historical data, put logs, IOC statuses, and IOC network information. It integrates these data points to offer a comprehensive view. The user interface of the platform leverages Web technology, with the server-side developed in the Node.js environment. This is complemented by software modules from the EPICS community. In addition, programs for network information collection and other cyclical executions are developed using the Python language. At present, the EPICS PV information platform has been successfully implemented in the CSNS accelerator, where it has significantly contributed to its effective operation and maintenance.
Subjects: Physics >> Nuclear Physics submitted time 2023-11-01
Abstract： Carbon ion radiotherapy is expected to become a workhorse for head and neck tumors radiotherapy due to its inverted depth dose distribution and high relative biological effectiveness, which has the advantages of less damage to normal tissues and low side effects. The accuracy of dose algorithms directly affects the accuracy of clinical irradiation doses, and reducing the dose calculation error of carbon ion radiotherapy could help improve patient’s survival and local control rates. In this paper, the dose distribution of carbon ion radiotherapy for 5 head and neck patients were calculated by the analytic pencil beam algorithm and validated using Monte Carlo method. Three analysis methods were carried out for the calculated and simulated results: (1) Gamma pass rate analysis under multiple evaluation criteria combination (2%/2mm, 3%/2mm, 3%/3mm, 3%/5mm), (2) DVH and reference index analysis, (3) central axis dose curve comparison. The analysis results showed that the average gamma pass rate of the pencil beam algorithm was 90.441% under the evaluation criteria of 3%/2mm, which met the dose calculation requirements of carbon ion radiotherapy for head and neck tumors. The pencil beam algorithm calculated more accurate in the beam transverse direction, and there is a range deviation by which the structure inhomogeneity and cavity exited in the irradiation path. In order to reduce the impact of dose calculation error, a more conservative angle selection to carbon-ion beam treatment of head and neck tumors is recommended. The results herein could be used to guide the design of carbon ion radiotherapy for head and neck tumors based on analytical pencil beam algorithm.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Geography submitted time 2023-09-19 Cooperative journals: 《干旱区地理》
Abstract： Soil salt crust has an important impact on soil evolution and ecohydrological processes in arid areas.There are few recent studies on water and salt distribution characteristics in salt-crust soils, and the influence ofsalt-crust thickness is not considered, leading to great differences in research results. Therefore, in this paper, fourinitial salt concentration treatments (0 g·L−1, 10 g·L−1, 150 g·L−1, and 250 g·L−1) were set to obtain different saltcrust thicknesses (4.5 mm, 6.6 mm, 7.3 mm) through laboratory simulation tests, and the soil-profile dynamics ofwater and salt were compared and analyzed using a partial repeated stepwise withdrawal method. The resultswere as follows: (1) Compared with the non-salt treatment, the thicker the salt crust, the larger the soil-profile water content, and the smaller the salt-content variation range. (2) At the end of the experiment, the water contentdistribution characteristics of the 4.5 mm salt-crust soil were similar to those of the unsalted treatment, and thewater contents of the 6.6 mm and 7.3 mm salt-crust soils were significantly higher than that of the unsalted treatment (P<0.05). (3) At the end of the test, the minimum salt contents of the 4.5 mm, 6.6 mm, and 7.3 mm saltcrust soils decreased by 90.5%, 46.3%, and 32.1%, respectively, compared with their initial salt contents. The results confirm that salt-crust thickness has a great influence on the distribution of soil water and salt. Therefore, itis suggested that the influence of salt-crust thickness should be considered comprehensively in future research ondistribution characteristics of water and salt.
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