Table of Content

20 May 2023, Volume 59 Issue 3

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Modelling Methods of Constrained Flexible Ropes in Capture Net System

LI Zhixiang, ZHANG Hanglan, SHI Junwei, YANG Wenmiao, ZHAO Zhen

2023, 59(3):  359-364.  DOI: 10.13209/j.0479-8023.2023.014

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Due to the difficulty of dynamical modelling of constrained flexible ropes for the closure process caused by the presence of non-smooth contacts and rigid-flexible coupling problem, a simplified model is provided. The contacts between the ropes and the rings or the separators are considered as slip joints, and the dynamical studies are conducted using the constraint method. Considering the collision of the slip joint, the contact stiffness is introduced and the contact dynamics equations of the slip joint are established. The absolute nodal coordinate formulation is used to describe the motion of rope element, and the dynamics model of which can then be established through the principle of virtual work. For rigid bodies such as separators, the quaternion description is used to establish the dynamics equations. The simulation of closure process is performed to obtain the motion law of the rope and the traction mass block, and the closure time and the degree of closure are compared under different numbers of rings. It is found that an increase in the number of rings will result in a more compact contraction of the rope, but considerable rings will prolong closure time and reduce closure efficiency.

Characteristics of Isokinetic Strength of Thigh Muscles 12 Months after Anterior Cruciate Ligament Reconstruction

SHI Huijuan, ZHANG Dongxia, REN Shuang, LIANG Zixuan, LI Hanjun, HUANG Hongshi, AO Yingfang

2023, 59(3):  365-374.  DOI: 10.13209/j.0479-8023.2023.032

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In order to investigate the isokinetic strength of the thigh muscles at different knee flexion angles in patients 12 months after anterior cruciate ligament (ACL) reconstruction, an open-chain concentric and eccentric tests of the quadriceps and hamstring were performed at an angular velocity of 60°/s in 16 males 12 months after ACL reconstruction and 14 healthy controls. The peak muscle strength of different contraction patterns at different knee flexion angles were analyzed and the following ratios were calculated: the concentric ratio of hamstring to quadriceps (Hc/Qc), the eccentric ratio of hamstring to quadriceps (He/Qe), the eccentric ratio of hamstring to the concentric ratio of quadriceps (He/Qc), and the concentric ratio of hamstring to the eccentric ratio of quadriceps (Hc/Qe). A two-way ANOVA with mixed design was used to examine the effects of groups and legs on isokinetic muscle strength characteristics. The following results can be concluded. The hamstring strength characteristics were similar at different knee flexion angles, with the reconstructed leg being significantly smaller than the contralateral leg and not different from the healthy controls. In contrast, the isokinetic quadriceps strength showed angle specificity, and the concentric quadriceps strength of the reconstructed leg at 40° and 50° of knee flexion differed not only from the contralateral leg but also from the healthy control leg, making it a more specific index for assessing muscle strength characteristics. Attention should be paid not only to bilateral symmetry but also to whether it is restored to the level of healthy individuals, emphasizing the recovery of muscle function at specific angles in rehabilitation. The flexion-extension strength ratios of bilateral lower limbs at smaller flexion angles differed from those of healthy controls, suggesting that postoperative rehabilitation should strengthen the control training of knee flexion movements of the reconstructed leg and improve the cushioning control ability of the contralateral leg. 

Change in Delay Time of S-Wave Splitting during Moderate and Small Earthquake Swarms in Tengchong Area

ZHENG Yiquan, LEI Jun

2023, 59(3):  375-387.  DOI: 10.13209/j.0479-8023.2023.001

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The spatio-temporal distribution of delay time of S-wave splitting is analyzed based on 260 shear wave time-delay data from local earthquakes in Tengchong area, Yunnan Province. The result shows that the changes in delay time of S-wave splitting are related to the magnitude of three moderate and small earthquake swarms, and delay time of S-wave splitting changes synchronously with the occurrence of the main shock and larger aftershocks in the earthquake swarm which carries the information of stress change during the earthquake swarm, provided that the locations of all earthquakes in the same earthquake swarm are concentrated, thus excluding the influence of differences in propagation path length and spatial azimuth of seismic ray path on delay time of S-wave splitting. Different from most cases in the past, the magnitude of the earthquake swarm in this work is relatively small, with the maximum magnitude ranging from M3.2 to M5.2. At the same time, the distances between the earthquake swarms and the stations are relatively large, generally greater than 30 km, and the largest reaches about 70 km. The information of stress changes during moderate and small earthquakes has been obtained by analyzing delay time of S-wave splitting from distant stations, which has great implications for the wider use of distant small earthquakes to monitor regional stress changes.

Study on Influencing Factors of Pre-Stack Reverse Time Migration Imaging of Ground Penetrating Radar

MA Bowen, HUANG Qinghua

2023, 59(3):  388-394.  DOI: 10.13209/j.0479-8023.2023.015

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To analyze the influence of various possible errors in the actual ground-penetrating radar data processing on the imaging effect of the reverse time migration algorithm, numerical simulation tests are used to analyze the effect of the velocity errors in model and noises in data. For velocity error, models with different velocities and abnormal body depths, and simplified velocity models are used to test the subsequent imaging effect. Results show that with the increase of the velocity error and the depth of the abnormal body, the deviation of the position of the abnormal body also increases. For the layered structure with slight differences in velocity between each layer, imaging using a simplified uniform half-space model can still effectively distinguish the anomalies. Imaging tests are also performed on data with different noise levels. The results show that the reverse time migration (RTM) algorithm is effective on noise suppression. Even if the signal-to-noise ratio of the valid signal in the received data is around ?15 dB, the RTM algorithm can still image the corresponding structure.

Is There an Interconnected Lower Crustal Channel Flow beneath Southeastern Margin of Tibetan Plateau?

NING Shuoxian, CHEN Yongshun

2023, 59(3):  395-406.  DOI: 10.13209/j.0479-8023.2023.018

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A 3-D shear wave velocity model of Southeastern Margin of Tibetan Plateau crust was constructed by Markov Chain Monte Carlo inversion, based on Rayleigh wave phase velocity tomography results which are obtained from ambient noise interferometry and tele-seismic two plane wave analysis, using seismic data of 137 permanent stations from China digital seismic network and 332 portable stations from ChinArray. The velocity model indicates the presence of an interconnected lower crustal channel flow in southeastern margin of Tibetan plateau, which is represented by an interconnected low shear wave velocity zone with Vs < 3.55 km/s. It consists of three parts which respectively locates beneath the Panzhihua area and to its west and east. The lower crustal channel flow from Tibetan Plateau is blocked by rigid lower crust of the Sichuan block and turns to flow through Emeishan area to the south direction, which alters the lower crust of Emeishan large igneous province (ELIP) together with the lower crustal channel flow beneath Pahzhihua area, thickening the crust in this area. It is infered that the lower crustal channel flow beneath the southeast margin of Tibetan Plateau ends at about 24°N, and has the potential to extend further south, which has the role to extend the scope of crustal thickening in the future.

Analysis of the Reasons why Surface Wave Magnitude is Higher than Moment Magnitude in the Mainland of China from the Perspective of Source Rupture Parameters

XU Yueyi, ZHANG Yong

2023, 59(3):  407-414.  DOI: 10.13209/j.0479-8023.2023.020

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The influence of the source parameters on M_s is studied through numerical simulations based on finite-fault models. The results show that the M_s is negatively correlated with earthquake rupture duration when moment magnitude remains unchanged. The source parameters that can impact the rupture duration contain the sub-fault duration, rupture velocity, and rupture length. Among them, the sub-fault duration and rupture length is negatively correlated with M_s, while the rupture velocity is positively correlated with M_s, if the moment magnitude remains unchanged. The fact that the measured M_s of strong earthquakes in the mainland of China are significantly larger than moment magnitudes may be due to two reasons. First, the strong earthquakes in the mainland of China are mostly intraplate earthquakes with relatively higher stress drop values, which may have short rupture duration and rupture length. Secondly, M_s determined by China Earthquake Networks Center (CENC) is systematically larger than M_s(20) determined by National Earthquake Information Center.

Formation of Chert Breccia from the Transitional Beddings between Neoproterozoic Jingeryu Formaiton and Cambrian Fujunshan 

Formation in Xiaweidian Section, Beijing

LI Chenqing, DONG Lin, SHEN Bing

2023, 59(3):  415-426.  DOI: 10.13209/j.0479-8023.2023.017

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To investigate the specific processes of deposition and environmental changes in the North China Block during Late Neoproterozoic to Early Cambrian when it received deposition again after a depositional hiatus, chert breccia of the Qingbaikou Series Jingeryu Formation and the Lower Cambrian Fujunshan Formation in the Xiaweidian section of Xishan area of Beijing was analyzed. Based on petrological and geochemical studies, chert layers in Jingeryu Formation and chert breccia in the bottom of the overlying Fujunshan Formation have similar Ge/Si ratios and rare earth element patterns. It indicates that Fujunshan chert breccia might originated from Jingeryu Formation. Breccia-bearing dolomite in the bottom of the Fujunshan Formation is block-shaped, without bedding. The breccia is mixed in component and size, with poor sorting and roundness, and disorderly arranged. Breccia-bearing dolomite in the bottom of Fujunshan Formation may represent glacial deposits.

Study of the Spherical Fossils from the Ediacaran-Cambrian Liuchapo Formation in Guizhou, China

LIU Hui, DONG Lin

2023, 59(3):  427-433.  DOI: 10.13209/j.0479-8023.2023.016

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Microfossils from cherts of the Liuchapo Formation at Bahuang section in eastern Guizhou Province were studied. Through thin section observation, a large number of spherical fossils were revealed, including one type with connected spheroids, and two types with dark outer wall. The former is systematically described, and a new genus Bahuangia gen. nov. is established. The connected bodies of Bahuangia are calabash- or chain-shaped, and resemble the budding unicellular fungi or bacteria in morphology. Spherical fossils similar to these Bahuang specimens are widely distributed in the late Ediacaran deep-water facies of the Yangtze Plate. Through this study, the understanding of deep-water life forms during the ECT is improved, and new materials for both regional stratigraphic correlation and early life evolution are provided.

A Spatially Constraint Negative Sample Generation Method for Geographic Knowledge Graph Embedding

GAO Yong, MENG Haohan, YE Chao

2023, 59(3):  434-444.  DOI: 10.13209/j.0479-8023.2023.002

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Geographic knowledge graph representation learning requires generating the corresponding negative samples based on the positive ones. However, traditional negative sample generation algorithms suffer from high error rate and poor adaption to geographic knowledge graph. Aimming at this problem, a spatially constraint negative sample generation method was proposed by modifying the modeling of spatial relations. Then the method was applied to different knowledge graph representation learning models to explore its suitability in geographic knowledge graph embedding. Results show that the proposed method has a low error rate and is suitable for two common types of knowledge graph representation models. The spatially constraint negative sample generation method will improve the accuracy of geographic knowledge graph representation learning, which helps to advance geographical research.

Applicability Study on Parallax Bundle Adjustment in 3D-Photography

ZUO Zhengkang, YAN Lei, SUN Yanbiao, ZHAO Hongying, ZHANG Ruihua, SUN Jiayu, LIU Siyuan, WANG Qiang, SUN Yiyuan

2023, 59(3):  445-455.  DOI: 10.13209/j.0479-8023.2023.033

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In order to study the applicability of the Parallax Bundle Adjustment (PBA) in the 3D-photography, the authors extend the mathematical proof of the PBA model which is based on the two-dimensional hypothesis, to three dimensions with respect to the sensitivity of parallax angle to observation noise, the singularity of the normal equation, and the degree of linearization. Furthermore, with a set of narrow intersection-angles (2.11×10^-8 to 2.11×10^-12 rads), the 3D-scenes in short-baseline photography are simulated, and employed to verify the proof. Theoretical analysis and experimental results demenstrate that the current version of PBA is only suitable for the 2D-photography, but not suitable to solve the short-baseline problem in the 3D-photography.

Text Classification Model for Livelihood Issues Based on BERT: A Study Based on Hotline Compliant Data of Zhejiang Province

KONG Xiangfu, DONG Bo, XU Ke, TAO Yongliang

2023, 59(3):  456-466.  DOI: 10.13209/j.0479-8023.2023.030

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Using the 12345 hotline compliant data from 2017 to 2021 in Zhejiang Province, a fine-grained three-level classification system for livelihood issues was constructed from the perspective of social cognition. A BERT pre-training model was developed to convert complaint texts into labels for livelihood issues. The validation result showed that adding 30% artificial complaint texts in the training set could increase roughly the accuracy rate by 10 percent, and the accuracy rate could be as high as 84.59%. Moreover, livelihood issue proportions of environmental protection, irregular business and municipal services had shown downward trends, while proportions of public services, traffic managements, house purchase issues, and emerging consumption patterns had shown upward trends. This study showed great values of combining the deep learning technology with 12345 hotline compliant data in improving data-driven social governance capabilities.

Network Features of Root-Associated Fungi of Pinus Sylvestris var. Mongolica Plantations and Response to Climate Factors in the Mu Us Desert

LIU Ye, REN Yue, GAO Guanglei, DING Guodong, ZHANG Ying, ZHAO Peishan, WANG Jiayuan

2023, 59(3):  467-477.  DOI: 10.13209/j.0479-8023.2023.031

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To reveal the dynamic characteristics of root-associated fungal communities of P. sylvestris plantation, the co-occurrence network of root-associated fungi in P. sylvestris plantation were analyzed by using molecular ecological network analysis in the Mu Us Desert and its response to climate factors in different stand ages (27 a, 33 a and 44 a) and their annual growth stages (early growth season, vigorous growth season and end-of-growth season). The following conclusions are obtained. 1) Different growing seasons rather than different stand ages had significant differences in the co-occurrence network of fungi in roots of P. sylvestris plantation, and the co-occurrence network of fungi in roots was more complex in the vigorous growing season. 2) The keystone species of root-associated fungi of P. sylvestris plantation were significant in different growing seasons and stand ages. The keystone genera mainly included Geopora, Tomentella, Phaeosphaeria, Neocucurbitaria, Mortierella, etc. Ectomycorrhizal and saprophytic fungi were the keystone taxa in the early and end of the growth season, and saprophytic fungi and pathogens were the keystone taxa in the vigorous growth season. Meanwhile, the keystone taxa of middle-aged forest were saprophytic fungi and pathogens, while the mature forest were ectomycorrhizal and saprophytic fungi. 3) Relative humidity was the main influencing factor for ectomycorrhizal fungi network, and average precipitation and relative humidity were the main influencing factors for saprophytic fungi network and pathogens network (P<0.05). Therefore, the network dynamic of root-associated fungi of P. sylvestris plantation in different growing seasons was stronger than that of stand age in Mu Us Desert, and the co-occurrence network structure was more complex in the vigorous growth season. The root-associated fungal network was mainly affected by average precipitation and relative humidity. Saprophytic fungi played an important role in maintaining the stability of the fungal network in different stand ages and growing seasons. Saprophytic fungi and pathogens in the vigorous growth season with high precipitation and relative humidity, which potentially contributed to the growth and health of P. sylvestris plantation. 

Evolution and Driving Factors of “Production-Living-Ecological Space” in Rural-Urban Fringe of Beijing

ZHANG Hao, FENG Changchun, GUO Yongpei

2023, 59(3):  478-488.  DOI: 10.13209/j.0479-8023.2023.008

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Taking Chaoyang District of Beijing as an example, this paper identified Production-Living-Ecological Space in rural-urban fringe, and described the spatial pattern evolution with the help of transformation matrix and spatial analysis tools. On this basis, the spatial metrology models were selected to analyze the driving factors of space conversion. The results show that, 1) from 2005 to 2020, according to the spatial order from near to far from the city center, the scale of Production Space was reduced and concentrated, the Ecological Space formed a green ecological landscape belt in the periphery of Beijing, the Eco-Agricultural Production Space and the Life-agricultural Production Space were rapidly reduced, and the Living-Non-farm Production Space was rapidly expanded in the point-line-plane order. 2) From 2005 to 2020, the shift of Production Space to Living-Non-farm Production Space was always the main direction of conversion, the Living-Non-farm Production Space continued to gain a large amount of inflow, and finally became the largest space type in the study area. 3) From 2005 to 2010, driven by population, economy and industrial factors, the Production Space converted into Living-Non-farm Production Space, and Eco-Agricultural Production Space converted into Production Space. From 2010 to 2015, population and economic factors further drove Production Space to Living-Non-farm Production Space. From 2015 to 2020, driven by the policy and industrial factors, the Production Space converted into Living-Non-farm Production Space or Ecological Space.

Integration of Towns and Industrial Zones in Pearl River Delta: A Case Study of Shishan and Songshanhu

CAO Jiyang, GONG Yue, LI Jiheng, PENG Hui

2023, 59(3):  489-500.  DOI: 10.13209/j.0479-8023.2023.023

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Shishan in the city of Foshan and Songshanhu in the city of Dongguan in the Pearl River Delta are typical examples of integration of towns and industrial zones and dynamic mechanism of urbanization. Based on land use data of 2015 in Guangdong Province and the socioeconomic data of 2016 in two cities, the study examines the attributes, patterns, and mechanisms of the integration from the perspective of governance and has four findings. 1) Integration of industrial zones and towns is a form of urban-industrial integration at the scale of villages and towns, and its connotation includes institutional integration, spatial and functional integration, and urbanization. 2) Shishan adopts a gradual renewal of the integration of industrial zones and towns, and forms a spatial structure of the core that drives the development of the periphery. Songshanhu adopts the development model of planning the entire zone and town to form multiple functions of subzones. 3) The zone-town system is affected by internal and external forces. The external forces include globalization, land finance, and national and regional policy adjustment. As coordinating force, development force, and supporting force, the three pivotal elements of institution, industry, and urbanization function promote the integration. 4) As the key actor of the main external power, local governments lead the development of integration. Shishan restructs the system, industry and urbanization at the town scale, and gradually integrates them; Songshanhu deploys the localization of institution and industries to promote the integration. As a result, both Shishan and Songshanhu have transformed the previous development model of villages and towns in the Pearl River Delta, and promots the integration of towns and development zones. 

General Method Framework of Designed Ecosystem and Its Application in Typical Habitat Creation Modes

WANG Zhiyong, LI Jianing, LIU Jiaju, PENG Xiao

2023, 59(3):  501-512.  DOI: 10.13209/j.0479-8023.2022.113

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Based on the principles of ecology and design, the general method framework of designed ecosystem was put forward. The framework is guided by the provision of integrated ecosystem services and based on the basic laws of the ecosystem, which aims to create a balanced habitat of soil and water, configure a stable and orderly local biological network, and design recreation facilities with minimum intervention. At the same time, according to the practice of ecological restoration design and the classical ecological engineering design guides, this study summarized the key design parameters of the designed ecosystem from three aspects: structure, materials and auxiliary measures, a total of 31 items. On this basis, to engineer the traditional ecological wisdom, specific design methods and quantitative parameters of terrace, impounding-pond, dike-pond and stacking-fields habitat creation modes in the aspects of basic model characteristics, habitat unit shaping, water cycle regulation, soil environment regulation, biological community allocation and recreation facilities construction were put forward. This result provides an engineering and replicable method for the practice of large area ecosystem restoration engineering in China.

Spatial Pattern Evolution and Carbon Effect of Production-Living-Ecological Space in Zhangjiakou City under Carbon Peak and Carbon Neutrality Goals

LIU Tianhao, JI Zhengxin, DUAN Yaming, XU Yueqing

2023, 59(3):  513-522.  DOI: 10.13209/j.0479-8023.2023.025

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This study analyzes the evolution characteristics of “production-living-ecological” space in Zhangjiakou City during the period of 2000–2020, measures its carbon effect in the vertical and horizontal directions, and discusses its ecological relationship and its impact on carbon effect, based on the relationship between “production-living-ecological” space and carbon source/carbon classification system. The results show that “production-living-ecological” space in Zhangjiakou has changed significantly during 2000–2020, with an increase of 710.24 km² in ecological space, 652.55 km² in production-living space and a decrease of 1362.79 km² in production-ecological space. The transformation of the three types of space has become more intense from 2000 to 2020 in Zhangjiakou City. Vertically, the carbon flux of Zhangjiakou City increases from 26.9518 million tons to 48.9436 million tons. Carbon emission is more than carbon uptake and the imbalance of carbon budget is serious during 2000–2020. Horizontally, the carbon absorption intensity of ecological space gradually increases, and the carbon emission intensity of production-ecological space and production-living space continues to decline in Zhangjiakou City. In the past 20 years, the positive carbon flow has increased by 8.23 million tons, and the negative carbon flow has decreased by 11.82 million tons, but the overall net carbon flow is still negative. The spatial ecological relationship among the “production-living-ecological” space has obvious conflicts, mainly manifested as plundering-restriction and competition relationship, showing a negative impact on the carbon.

Realization Path of Comprehensive Tourism in Leisure Agriculture Based on Perspective of Element Flow: A Case Study of Chongqing

LU Qingling, LIU Yuexin, GAO Yang, ZHANG Zhonghao, CUI Lihan, SUN Ximan

2023, 59(3):  523-531.  DOI: 10.13209/j.0479-8023.2023.026

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In order to break the static distribution of leisure agricultural tourism, taking Chongqing as an example, the spatial domain is constructed based on the perspective of element flow, and the “source-sink” theory is applied. The results show that traditional leisure agricultural tourism in Chongqing mostly relies on cultivated land, forest land and grasslands, and the land space structure is compact, with the main urban area as the axis or along the Yangtze River. The comprehensive ecological sensitivity of Chongqing is relatively low, with moderate and mildly sensitive areas accounting for 62.49% of the total. The constructed “source-corridor” spatial domain includes 6 leisure agricultural tourism sources and 18 element flow corridors. Based on the spatial layout of “one center and two rings, one corridor and two wings”, the continuity and sustainability of leisure agricultural tourism in the whole area can be realized through the strengthening of 40 key nodes and the improvement of 18 corridors network. The research results can provide a theoretical basis for the spatial distribution of tourism in Chongqing, and promote the innovative practice of comprehensive tourism management.

Responses of Soil N₂O Emission to Litter Removal and Root Removal: A Meta-Analysis

ZHOU Daiyang, FENG Jiguang, ZHU Biao

2023, 59(3):  532-538.  DOI: 10.13209/j.0479-8023.2023.027

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Based on litter removal and root removal experiments carried out worldwide, 61 pairs of soil N₂O emission data were obtained, and the effects and regulatory factors of litter removal and root removal on soil N₂O emission were quantitatively evaluated by the meta-analysis approach. The results showed that soil N₂O emission decreased (?16.5%) significantly after removing litters, but increased (+131.6%) significantly after removing roots. The response ratio (RR) of soil N₂O emission was positively correlated with the RR of soil moisture and nitrate nitrogen content under litter and root removal treatments, which suggested that soil moisture and nitrate nitrogen content were the main factors regulating the response of soil N₂O emission to reduced plant inputs. Overall, the results reveal the effects of litter removal and root removal on soil N₂O emission and regulatory factors for such effects, which is helpful to understanding how altered plant inputs will regulate soil N₂O emissions in the context of future global change.