Table of Content

20 November 2024, Volume 60 Issue 6

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Research on Range Expansion Technology of Charge Sensitive Preamplifier for Particle Radiation Detector

WANG Youlong, YU Xiangqian, WANG Linghua, CHEN Hongfei, SHI Weihong, CHEN Ao, WANG Yongfu, YANG Xin, ZONG Qiugang, ZOU Hong

2024, 60(6):  973-978.  DOI: 10.13209/j.0479-8023.2024.090

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The particle radiation detector readout ASIC RENA3 (Readout Electronics for Nuclear Applications) is widely used as preamplifier for its low-noise, but the maximum input charge of RENA3 limits its range. This paper proposes a method to realize the range expansion by paralleling the capacitor at the input of RENA3. Theoretical analysis, PSpice simulation analysis and experimental verification were carried out. The experimental results are consistent with the theoretical analysis and numerical simulation results, which verify the feasibility of the method. This method can also be used to expand the range of other ASIC.

Leveraging Graph Structure and Simple Recurrence for Map Matching

LUO Wei, LIU Yu, HUANG Qiang, WU Zhihao

2024, 60(6):  979-988.  DOI: 10.13209/j.0479-8023.2024.087

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Existing solutions for map matching mainly rely on sequence-to-sequence models to capture the correlations within a trajectory while neglecting the correlation between road segments and trajectories as well as trajectory-road correlations. Meanwhile, recurrent neural networks suffer from inherent limitations in conducting computations efficiently in parallel. To fully exploit all the aforementioned correlations and to improve the model parallelism, a Graph-enhanced Map Matching model with Simple Recurrence (GMMSR) is proposed. The model captures the correlations between road segments and trajectories through road network convolution and trajectory graph convolution respectively, and exploits the trajectory-road correlation by aligning road network and trajectory representations in latent space. Moreover, the model utilizes simple recurrent units to achieve more efficient parallel computations. Extensive experiments on a map matching dataset in a subarea of Beijing demonstrate significant improvements in accuracy compared with existing baselines while achieving comparable or better efficiency.

An Image Segmentation Based Technology for Intelligent Character Creation

JIANG Jianbin, HUANG Song, WU Jiangguo

2024, 60(6):  989-1000.  DOI: 10.13209/j.0479-8023.2024.088

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Currently, the intelligent character creation technology based on style learning generates fonts with low similarity to the user’s handwritten style, and the method based on Graphics Processing Unit (GPU) style transfer is expensive. To solve the problems above, a new intelligent character creation method is proposed using deep learning and image segmentation technology, which can maintain a highly similar style while meeting the personalized needs and reducing the generation cost. Using DeepLab v3+ technology, 775 font images input by users are filtered by a data quality evaluation model and are split to components by image segmentation models. Then, components are finely adjusted and noise is removed, and finally TrueType fonts are generated after vectorization. Compared with existing technologies, this method significantly improves the similarity and reduces the cost, and can effectively meet the personalized customization needs of users.

Implementation of an Improved LeNet Traffic Sign Multi-classification Heterogeneous Accelerator

YANG Yongjie, ZHENG Juntai, MA Li, YANG Hao

2024, 60(6):  1001-1008.  DOI: 10.13209/j.0479-8023.2024.089

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An implementation of traffic sign multi-classification heterogeneous accelerator based on improved LeNet is proposed. The accelerator utilizes an ARM+FPGA heterogeneous platform to deploy the forward inference of the improved LeNet on the FPGA for parallel computing. On the FPGA side, the AXI-Stream protocol is employed with DMA to achieve high-speed data streaming, and techniques such as array partitioning and multi-level pipeline are utilized for parallel data processing. On the ARM side, the PYNQ framework is used for data updates and accelerator scheduling. Experimental results on GTSRB demonstrate that proposed design achieves an average inference time of 14.489 ms at a working clock frequency of 50 MHz, compared to 710 ms on the MCU, resulting in a speedup of up to 49 times. This design provides significant assistance for edge applications involving traffic sign multi-classification.

An Optimal Post Processing Detection Method for Underwater Broadband Signals of High-Order Sound Field

WANG Qiang, WU Xihong, PAN Yue, GAO Shan

2024, 60(6):  1009-1014.  DOI: 10.13209/j.0479-8023.2024.091

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According to the weak resolution of small aperture high-order acoustic field sensors under actual multi-target interference conditions in marine environment, a broadband signal optimal detection based on the subset of high-order sound field domain post-processing method is proposed. This method utilizes the characteristic of typical noise fields that signals in different orders of the high-order sound field are decorrelation. The signal power and noise power within one beam are estimated through the subset of high-order acoustic signals with MVDR. An optimal beam domain detection filter based on the signal-to-noise ratio of each subband is constructed. This method is verified through multiple measured dataset on Qiandao Lake. The detection capability is improved by 2–7.5 dB compared with the original method, and the multi-target resolution capability under strong target interference is significantly improved.

Improved Multi-objective Dung Beetle Optimizer Based on Non-dominated Sorting for Optimizing Microgrid Scheduling with Clean Energy

WEN Xialu, HUANG He, RU Feng, LIU Guoquan, WANG Huifeng

2024, 60(6):  1015-1027.  DOI: 10.13209/j.0479-8023.2024.068

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In order to solve the problem of intra-network distribution of power resources in microgrid containing clean energy, it is necessary to coordinate the optimization of economic cost and low carbon energy saving, and the existing multi-objective Dung Beetle Optimizer (DBO) algorithm lacked the optimization ability. An improved multi-objective DBO based on non-dominated sorting (NSIDBO) was proposed. Firstly, a microgrid system containing wind-fuel storage and physical constraints of each device was constructed, and a multi-objective cost function based on economy and low carbon was established. Secondly, the Tent mapping based on the disturbance factor was designed, and three parameters were added on this basis to increase the mapping distribution range and improve the initial population diversity. Then, a new type of non-dominated sorting was introduced to find the optimal Pareto front. The roll tracking optimization strategy was designed, and the dynamic step size updated the ball roller to increase the global exploration ability and optimization accuracy of DBO. Finally, an adaptive internal division mechanism was designed to update the proportion of rolling balls and dung beetles, which further improved the convergence of the algorithm. Simulation experiments are conducted on typical 24-hour daily load data provided by IEEE-RTS. The results show that compared with the five comparison algorithms, the proposed NSIDBO method has better comprehensive performance and plays a guiding role in realizing safe and stable control operation of the microgrid. 

A 2-D Ocean Modeling Study of the Multicentennial Variability of the Atlantic Meridional Overturning Circulation

WANG Shuxiang, YANG Haijun

2024, 60(6):  1028-1036.  DOI: 10.13209/j.0479-8023.2024.070

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A simple ocean circulation model is used to study the multicentennial variability of the Atlantic meridional overturning circulation (AMOC). Firstly, a latitude-averaged 2-D ocean circulation model is derived, and the control equation and key parameters for AMOC are established. Then, through numerical methods, a reasonable mean climate of AMOC is simulated under appropriate boundary conditions and external forcings. To excite the multicentennial variability of AMOC, a long-term integration is carried out by adding a random salinity flux forcing to the subpolar surface layer of the Northern Hemisphere. Power spectrum analysis results show that AMOC can exhibit oscillations with a period of about 260 years. The first spatial mode obtained from the EOF decomposition of AMOC exhibits signals primarily in the deeper ocean basins, indicating that the multicentennial variability may be closely linked to changes in the deeper ocean. The relationship between the oscillation period and the volume of the ocean basin as well as the strength of AMOC is also explored. Larger basin volumes are associated with longer oscillation periods, while stronger AMOC correlates with shorter periods.

Response of Earth’s Climate to Orbital Changes in Late Ordovician

YU Haonan, LIU Yonggang, LIN Qinfan, WEI Mengyu, ZUO Haoyue, ZHANG Jian, ZHANG Lulu

2024, 60(6):  1037-1054.  DOI: 10.13209/j.0479-8023.2024.084

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 A series of sensitivity experiments on the Late Ordovician Earth’s climate under different orbital configurations were conducted using the atmosphere-ocean general circulation model CESM1.2.2. It was found that the local annual mean surface temperature could vary by more than 5.5℃ and the seasonal temperature by more than 23℃ due to changes in orbital parameters. The global mean temperature was affected by less than 0.2℃ due to precession, and an increase of about 1℃ in the global mean temperature could be caused by a change in obliquity from 22.5° to 24.5°, due to the annual mean solar radiation received at high latitudes, together with the ice-albedo feedback. The global mean precipitation rate was found not to be impacted by orbital changes, but its spatial and temporal distribution was highly impacted; the north-south shift of the intertropical convergence zone was controlled by the precession, and an increase in precipitation at the poles was caused by increases in the obliquity. A great impact on the spatial pattern of summer monsoonal regions was also caused by orbital changes. A change in the global monsoon area by more than 40% could be caused by changes in precession; a mild effect on the mid-latitude and high-latitude monsoon area of approximately 10% was caused by obliquity. Although Late Ordovician was overall warm with its global mean surface temperature exceeding 18℃, deep snow can be accumulated over large areas of continents in the southern hemisphere under most orbital configurations, indicating the possibility of the formation of large ice sheets.

Investigation into Visualization of P-bearing Minerals Informatics

ZHUANG Ziyi, LI Yan, YIN Rongzhang, WU Junqi, LU Anhuai, LAI Yong

2024, 60(6):  1055-1066.  DOI: 10.13209/j.0479-8023.2024.077

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Network analysis, element correlation analysis and phylogenetic analysis are applied in the visualization methods study of mineral crystal chemistry data. Taking P-bearing minerals as an example, force-directed network and bipartite network diagram of mineral composition and genesis, phylogenetic tree of mineral crystal characteristics and correlation heat maps of mineral component elements are drawn. These methods also take into account the spatial and temporal distribution, evolutionary diversity and physical and chemical properties of minerals. The use of these visual analysis methods is helpful to explore the evolution of the Earth’s environment using mineralogical records through deep time and understand its evolutionary process and driving mechanism.

Environmental Effects on the Emplacement of 1.32 Ga Mafic Sills

ZHANG Chaokun, TIAN Wei, HE Yanxin, ZHU Weipeng, LI Shun

2024, 60(6):  1067-1078.  DOI: 10.13209/j.0479-8023.2024.069

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In order to explore the relationship between deep earth dynamics and global carbon cycling processes, environmental changes, and planetary evolution during the Mesoproterozoic era, the Huangtugui Section in Beijing was selected as a stratigraphic section for studying the characteristics and environmental effects on the emplacement of 1.32 Ga mafic sills in Yanliao area. Through petrological and numerical simulation analysis, it was found that the 1.32 Ga mafic sills intruded into the surrounding rocks with the form of “magma finger”, resulting in significant thermal effects on the surrounding rocks. The emplacement of the sills significantly increased the vitrinite reflectance of organic matter in the surrounding rocks, evolving from an immature stage to an overmature stage. The thermal degassing of the sills in North China Craton and North Australia Craton released an equivalent of 3.61×10¹² tons of CO₂, promoting the activation of carbon in the lithosphere and having obvious environmental effects.

Crust-Mantle Structure in Xiong’an New District and Its Implications for Continental Lithosphere Transformation

ZHANG He, JIANG Yiran, WANG Hongyu, WEN Jingchong, NING Jieyuan

2024, 60(6):  1079-1093.  DOI: 10.13209/j.0479-8023.2024.100

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Based on a newly developed AI-based method for extracting teleseismic Rayleigh wave dispersion curves by Y. R. Jiang, a large volume of high-quality teleseismic Rayleigh wave dispersion curves was obtained from very broadband dense seismic observation data collected by J. Y. Ning team from October 2022 to July 2023 with station spacing of approximately 16 km. Phase velocity imaging considering finite-frequency effects and S-wave velocity inversion based on the nonlinear Markov Chain Monte Carlo technique were conducted, yielding a S-wave velocity structure of the crust and mantle in the Xiong’an New District. The S-wave velocity structure indicates that the lower crust beneath the Taihang Mountains is in direct contact with asthenosphere, while a relatively thin lithospheric mantle exists beneath the North China Plain to the southeast of Taihang Mountains. The crust in the Taihang Mountains and its southeast adjacent area shows differences in the presence or absence of a thick mafic lower crust. The fault zone at the front of the Taihang Mountains has been the core area for the ascent of mantle thermal material, leading to the foundering of the ancient lithosphere since the Late Mesozoic. Since the Cenozoic, the region has undergone a tectonic process of lithospheric extension and cooling. This study also proposes a dynamic model for the high heat flow in the Xiong’an New District.

Changes in World Corn Shipping Pattern under the Background of COVID-19 Pandemic and Russia-Ukraine Conflict

ZHAO Pengjun, YIN Zhaoyou, ZHANG Mengzhu, NIU Yingnan, HE Zhangyuan

2024, 60(6):  1094-1106.  DOI: 10.13209/j.0479-8023.2024.023

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Using international corn trade data in 2019, 2021, and 2022, through matrix construction and algorithm design for data mapping, this paper explores the changes of the global corn shipping pattern under the background of COVID-19 pandemic and Russia-Ukraine Conflict. It is found that the Pan-Mediterranean Sea, the northwest Pacific coast area and the Caribbean Sea are the three cores of the world’s corn shipping. The epidemic and Russia-Ukraine conflict have a limited impact on the world corn shipping structure, and local changes are greater than the overall changes. The impact of Russia-Ukraine conflict on the world corn shipping pattern is concentrated in the Pan-Mediterranean region. The quantitative changes in the evolution of corn shipping pattern are still accumulating. Both the epidemic and Russia-Ukraine conflict have a dual effect in the volume of corn and freight rates. The Russia-Ukraine conflict interfers with the rebound of corn shipping in the world’s waterways after the easing of the epidemic. Considering the rising unit price of global shipping corn, the economic value of the Black Sea-related waterway has decreased significantly, and the economic value of waterway from South America around the Cape of Good Hope to East Asia and Southeast Asia shows a positive growth trend. The Pan-Mediterranean waterway is of highly comprehensive value. The western coastline of the African continent has low economic value but high international service value.

Spatial and Temporal Characteristics of Forest and Grassland Land Use Changes after the Implementation of Grain for Green Program in China

ZHANG Pu, YI Yuanyuan, XU Jintao

2024, 60(6):  1107-1122.  DOI: 10.13209/j.0479-8023.2024.081

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The study selected MODIS land use data and analyzed the spatial and temporal characteristics of forest and grassland after the implementation of the Grain to Green Program, as well as the impact of policy changes on the changes of forest and grassland. The following results are obtained. 1) After the program’s implementation, the overall trend of forest land and “cropland land broadly defined” including orchards in China showed a small upward trend, and the trend of grassland showed a downward trend. 2) Considering that part of the orchards and forest land have not destroyed the arable layer, which can be effectively restored to cropland, there is no tendency to lose the cropland, and the red line of 1.8 billion mu (1.2 million km²) of cropland is not currently under threat. 3) Returning cropland to forest mainly occurs in Yunnan Province, Sichuan Province, and Heilongjiang Province, accounting for 9.72%, 9.28%, and 7.68% respectively of the total area of cropland converted to forestland (109500 km²) nationwide. In contrast, the conversion of forestland to cropland mainly occurs in Sichuan, Hunan, and Guizhou Provinces, accounting for 18.47%, 9.59%, and 9.35% respectively of the area of forestland converted to cropland (104400 km²) nationwide. The simultaneous existence of a large number of both croplands converted to forest and forest converted to cropland in Sichuan and other provinces may be due to benign adjustments in geographic location and land quality, or it may be due to the regional heterogeneity of the policies of “food security” and “environmental protection”, which need to be further studied. 4) Half of the “forest land” after returning cropland to forests has been cultivated again after 18 years, some of it has been preserved as forest land (37%), and a tiny part of it has been degraded to grassland (3%) (taking the forest land cultivated in 2001 and returned to forests in 2002 as an example). 5) Subsidies for the Grain to Green Program can reduce the proportion of “forest land” converted from cropland for replanting crops, but increase the conversion of land from cropland to forest land where the natural conditions are unsuitable for afforestation. 

Change Pattern of Soil Moisture in the Qiannian Xiulin in Xiong’an

ZHENG Qiang, YANG Binyun, XIANG Yun, ZHENG Chengyang

2024, 60(6):  1123-1130.  DOI: 10.13209/j.0479-8023.2024.074

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To establish the Qiannian Xiulin (Millennium Forest of Xiong’an) that closely resembles a natural forest and is stable and self-adjusting, this study utilized soil precipitation and soil moisture data from 32 weather stations and the Qiannian Xiulin Regional Observation Station in Xiong’an New Area, Hebei Province. Machine learning and mathematical analysis methods were employed to investigate the change pattern of soil moisture content in the Qiannian Xiulin. The results indicate that the soil moisture content of the Qiannian Xiulin in Xiong’an is significantly influenced by the monsoon climate and exhibits distinct seasonal fluctuations. Specifically, soil moisture content increases slightly after soil thawing from January to March, gradually decreases from March to June, and reaches the lowest point in June. After June, it shows an upward trend, reaching the maximum in August, and then decreases again after September. The relative humidity of the surface soil at a depth of 0–10 cm in Qiannian Xiulin is positively correlated with precipitation, while the change pattern of relative soil humidity and precipitation in 20–30 cm and 30–50 cm soil layers are not obvious. There are differences in the impact of precipitation intensity on relative soil moisture in different soil layers. Significant changes in soil moisture will only occur when the daily precipitation exceeds 20 mm. The soil moisture content at these weather stations is consistent with the field observation data of Qiannian Xiulin. This study provides scientific soil moisture change rules for artificial planting management of the Qiannian Xiulin.

Spatio-Temporal Differentiation Characteristics and Influencing Factors of China’s Renewable Energy Development Level

MA Hua, FANG Yebing, BEI Yiming, LIU Qi, FANG Xianwei, CAO Weidong

2024, 60(6):  1131-1142.  DOI: 10.13209/j.0479-8023.2024.079

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Using China’s provincial panel data from 2011 to 2020, the temporal and spatial correlation relationship and influencing factors of China’s renewable energy development level were analyzed based on ESDA model and GTWR model. The results show that from 2011 to 2020, China’s renewable energy development level showed an upward trend, and regional differences gradually decreased. The level of renewable energy development of provinces was promoted from low level to high level. The spatial pattern of China’s renewable energy development level showed the characteristics of “east, middle and west” stepwise increase. The spatial agglomeration degree of renewable energy development level between provinces gradually decreased. Compared with the GWR model, the GTWR model can better fit the impact of various influencing factors on renewable energy development. Overall, electricity consumption has the most positive impact on the development of renewable energy. R&D funding has the most negative impact on renewable energy development, and there is significant spatial heterogeneity between the influencing factors.

Dialogue on Supranuclear Matter at the Dream Field: A Summary

ZHOU Enping, JIANG Jinchen, LUO Yudong, WANG Weiyang, XIA Chengjun, ZHANG Chen, XU Renxin

2024, 60(6):  1143-1156.  DOI: 10.13209/j.0479-8023.2024.097

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Understanding the equation of state of cold dense matter, i.e., those inside neutron stars, is a key problem in the multi-messenger astronomical era. In order to facilitate the scientific discussions between different communities in the relevant fields, particularly between nuclear physicists and astrophysicists, we have organized the Dialogue at the Dream Field (DDF2024). The participants explored various fields of topics such as pulsar astrophysics, transient phenomena, hadronic and nuclear matter, supra-nuclear matter with quark degree of freedom, numerical relativity, etc. This involved discussions on the mechanisms, model construction, observational impacts, and introductions of new facilities. In-depth exchanges were carried out through invited talks and free discussions, as well as a visit to view the FAST telescope.