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Structural Characteristics and Evolution of a Weighted Sino-US Container Shipping Network
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作者 ZHANG Tiantian XI Daping +3 位作者 JIANG Wenping FENG Yuhao WANG Chuyuan HU Xini 《Chinese Geographical Science》 SCIE CSCD 2024年第5期810-828,共19页
This study selected the Sino-US route data from the top 30 global container liner companies between December 1,2019,and December 29,2019,as the data source utilizing the complex network research methodology.It constru... This study selected the Sino-US route data from the top 30 global container liner companies between December 1,2019,and December 29,2019,as the data source utilizing the complex network research methodology.It constructs a Sino-US container shipping network through voyage weighting and analyzes the essential structural characteristics to explore the network’s complex structural fea-tures.The network’s evolution is examined from three perspectives,namely,time,space,and event influence,aiming to comprehens-ively explore the network’s evolution mechanism.The results revealed that:1)the weighted Sino-US container shipping network exhib-its small-world and scale-free properties.Key hub ports in the United States include NEW YORK NY,SAVANNAH GA,LOS ANGELES CA,and OAKLAND CA,whereas SHANGHAI serving as the hub port in China.The geographical distribution of these hub ports is uneven.2)Concerning the evolution of the weighted Sino-US container shipping network,from a temporal perspective,the evolution of the regional structure of the entire Sino-US region and the Inland United States is in a stage of radiative expansion and de-velopment,with a need for further enhancement in competitiveness and development speed.The evolution of the regional structure of southern China and Europe is transitioning from the stage of radiative expansion and development to an advanced equilibrium stage.The shipping development in Northern China,the Western and Eastern United States,and Asia is undergoing significant changes but faces challenges of fierce competition and imbalances.From a spatial perspective,the rationality and effectiveness of the improved weighted Barrat-Barthelemy-Vespignani(BBV)model are confirmed through theoretical derivation.The applicability of the improved evolution model is verified by simulating the evolution of the weighted Sino-US container shipping network.From an event impact per-spective,the Corona Virus Disease 2019(COVID-19)pandemic has not fundamentally affected the spatial pattern of the weighted Sino-US container shipping network but has significantly impacted the network’s connectivity.The network lacks sufficient resilience and stability in emergency situations.3)Based on the analysis of the structural characteristics and evolution of the weighted Sino-US con-tainer shipping network,recommendations for network development are proposed from three aspects:emphasizing the development of hub ports,focusing on the balanced development of the network,and optimizing the layout of Chinese ports. 展开更多
关键词 container shipping network structure characteristics network evolution voyage weighting improved Barrat-Barthelemy-Vespignani(BBV)model
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Changes in neurotransmitter levels,brain structural characteristics,and their correlation with PANSS scores in patients with firstepisode schizophrenia
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作者 Xian-Jia Xu Tang-Long Liu +1 位作者 Liang He Ben Pu 《World Journal of Clinical Cases》 SCIE 2023年第22期5215-5223,共9页
BACKGROUND In patients with schizophrenia,the brain structure and neurotransmitter levels change,which may be related to the occurrence and progression of this disease.AIM To explore the relationships between changes ... BACKGROUND In patients with schizophrenia,the brain structure and neurotransmitter levels change,which may be related to the occurrence and progression of this disease.AIM To explore the relationships between changes in neurotransmitters,brain structural characteristics,and the scores of the Positive and Negative Symptom Scale(PANSS)in patients with first-episode schizophrenia.METHODS The case group comprised 97 patients with schizophrenia,who were evaluated using the Canadian Neurological Scale and confirmed by laboratory tests at Ningbo Mental Hospital from January 2020 to July 2022.The control group comprised 100 healthy participants.For all participants,brain structural characteristics were explored by measuring brain dopamine(DA),glutamic acid(Glu),and gamma-aminobutyric acid(GABA)levels,with magnetic resonance imaging.The case group was divided into negative and positive symptom subgroups using PANSS scores for hierarchical analysis.Linear correlation analysis was used to analyze the correlations between neurotransmitters,brain structural character istics,and PANSS scores.RESULTS Patients in the case group had higher levels of DA and lower levels of Glu and GABA,greater vertical and horizontal distances between the corpus callosum and the inferior part of the fornix and larger ventricle area than patients in the control group(P<0.05).Patients with positive schizophrenia symptoms had significantly higher levels of DA,Glu,and GABA than those with negative symptoms(P<0.05).In patients with positive schizophrenia symptoms,PANSS score was significantly positively correlated with DA,vertical and horizontal distances between the corpus callosum and the infrafornix,and ventricular area,and was significantly negatively correlated with Glu and GABA(P<0.05).In patients with negative schizophrenia symptoms,PANSS score was significantly positively correlated with DA,vertical distance between the corpus callosum and the infrafornix,horizontal distance between the corpus callosum and the infrafornix,and ventricular area,and was significantly negatively correlated with Glu and GABA(P<0.05).CONCLUSION In patients with first-episode schizophrenia,DA levels increased,Glu and GABA levels decreased,the thickness of the corpus callosum increased,and these variables were correlated with PANSS scores. 展开更多
关键词 Brain structural characteristics Negative symptoms Neurotransmitters positive symptoms SCHIZOPHRENIA
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Diagnostic Study on the Structural Characteristics of a Typical Mei-yu Front System and Its Maintenance Mechanism 被引量:23
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作者 JIANG Jianying(蒋建莹) +1 位作者 NI Yunqi(倪允琪) 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2004年第5期802-813,共12页
In this paper, a typical mei-yu front process with heavy rainfall from June 12 to 15 in 1998 is analyzed. The results show that the mei-yu front is a front system which consists of an iso-theta(e) dense area with stro... In this paper, a typical mei-yu front process with heavy rainfall from June 12 to 15 in 1998 is analyzed. The results show that the mei-yu front is a front system which consists of an iso-theta(e) dense area with strong horizontal gradient, a deep-convective cloud tower band, a passageway transporting warm and moist air flow from the summer monsoon surge in the mid and low levels to the south of the mei-yu front, and a migrating synoptic scale trough to the north of the mei-yu front, which transports cold and dry air southward in the mid and upper levels. The maintenance of the mei-yu front is realized by: (1) is a positive feedback between the moist physical process enhancing frontogenesis and the development of the strong convective system in front of the mei-yu front; (2) the sustaining system to the north of the mei-yu front which is a migrating synoptic scale trough transporting cold and dry air to the mei-yu front and positive vorticity to the mesoscale system in front of the mei-yu front. 展开更多
关键词 mei-yu front structural characteristics maintenance mechanism moist physical process
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Structural Characteristics and their Significance for Hydrocarbon Accumulation in the Northern Slope of the Central Sichuan Paleo-uplift 被引量:4
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作者 TIAN Xingwang LIU Guangdi +13 位作者 LUO Bing YANG Yu WEN Long ZHANG Benjian CHEN Xiao SU Guiping SONG Zezhang PENG Hanlin ZHOU Gang YAN Wei YANG Dailin WANG Yunlong SUN Yiting DOU Shuang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2022年第4期1451-1470,共20页
Based on 2D and 3D seismic data,the latest drilling data and field outcrop data of the northern slope of the Central Sichuan paleo-uplift,the structural analysis method is used to analyze unconformity development char... Based on 2D and 3D seismic data,the latest drilling data and field outcrop data of the northern slope of the Central Sichuan paleo-uplift,the structural analysis method is used to analyze unconformity development characteristics and fault characteristics during the key structural transformation period,discussing the influence of the structural characteristics on the hydrocarbon accumulation of deep carbonate rocks.The results show that:(1)The two key unconformities of the Tongwan and Caledonian periods were primarily developed in deep carbonate rocks.Firstly,Tongwan’s unconformities are characterized by regional disconformities between the second and third members of the Dengying Formation,the top formation of the Sinian and the lower Cambrian,strips of which zigzag through the north and south sides of the study area.Secondly,the Caledonian unconformity is characterized by a regional unconformable contact between the lower Permian and the ower Paleozoic strata.From NE to SW,the age of the strata,which were subject to erosion,changes from new to old,the denudation distribution showing as a nose-shaped structure which inclines towards the ENE.(2)Boundary fault and transtensional strike-slip faults developed in the Sinian to Paleozoic strata.In profile,there are three types of structural styles:steep and erect,flower structures,’Y’and reversed’Y’type faults.In plane view,the Sinian developed extensional boundary faults extending in an almost NS direction,strike-slip faults developing and extending linearly in approximately EW,WNW and NE strikes in the Cambrian,with characteristically more in the south and less in the north.(3)The faults in the northern slope show obvious zonal deformations in transverse view as well as significant stages and stratified activity in a longitudinal direction.Among them,the activity of faults in the Sinian was the strongest,followed by the activity in the Cambrian period,the activity intensity of faults in the Permian period being the weakest.This fault activity can be divided into four periods:Sinian,Cambrian-Permian,the early Indosinian period and the late Indosinian-Himalayan period,the transtensional strikeslip faults being the products of oblique extensions of pre-existing weak zones in the Xingkai and Emei taphrogenesis,with a particular inheritance in the main faults.(4)Combined with hydrocarbon accumulation factors,it is considered that the epigenetic karstification of the Tongwan and Caledonian unconformities in the northern slope controlled the formation and distribution of carbonate karst reservoirs over a large area,also acting as a good pathway for oil and gas migration.The extensional faults developed at the margin of the NS trending rift,controlling the sag-platform sedimentary pattern in the Dengying Formation of the Sinian.Strike-slip faults in NE,WNW and ENE directions may control the microgeomorphological pattern inside the platform and intensify the differential distribution of grain beach facies.The multi-stage hereditary activity of strike-slip faults not only improved the porosity and permeability of the reservoirs,but also acted as the main channel of oil and gas migration,providing favorable conditions for the development of the current multi-layer gasbearing scenario in the northern slope of the Central Sichuan Basin. 展开更多
关键词 northern slope of paleo-uplift UNCONFORMITY structural characteristics hydrocarbon accumulation Central Sichuan paleo-uplift Sichuan Basin
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Effect of Pig Manure Application on Structural Characteristics of Humic Acids in Brown Soil 被引量:5
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作者 DOUSEN TANSHI-WEN 《Pedosphere》 SCIE CAS CSCD 1991年第4期345-354,共10页
The effect of application of pig manure (PM) on the structural characteristics of humic acids (HAs) of brown soil was studied in field and incubation experiments. The results showed that the number-average molecular w... The effect of application of pig manure (PM) on the structural characteristics of humic acids (HAs) of brown soil was studied in field and incubation experiments. The results showed that the number-average molecular weights (Mn), the ratios of C/ H, C/ N and O/C, the contents of carboxyl and phenolic hydroxyl groups, the content ofaromatic C, the values of E2, E4and λ Exmax of HAs all decreased; whereas, the contents of alkyl C and O-alkyl C, the ratio of carboxyl to phenolic hydroxyl groups, the degree of oxidation stability, the absorption intensity at 285 mμ (UV), and 2920cm-1 of HAs increased after the application of PM. The above results indicated that the molecular structure of HAs tended to be more aliphatic and simpler after the application of PM. 展开更多
关键词 humic acid pig manure application structural characteristics
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COMPARISON OF THE STRUCTURAL CHARACTERISTICS OF DEVELOPED VERSUS UNDEVELOPED MID-LEVEL VORTEXES 被引量:1
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作者 黄辉军 袁金南 +1 位作者 李春晖 毛伟康 《Journal of Tropical Meteorology》 SCIE 2014年第1期57-65,共9页
Using the NCEP 1°×1°reanalysis data,several obvious differences of the structural characteristics of developed versus undeveloped mid-level vortexes are studied.First,the central vorticity of the develo... Using the NCEP 1°×1°reanalysis data,several obvious differences of the structural characteristics of developed versus undeveloped mid-level vortexes are studied.First,the central vorticity of the developed mid-level vortex increases towards higher levels while the undeveloped one decreases.The low-level convergence structure maintains well in the developed mid-level vortex whereas the undeveloped one does badly.Second,on the one hand,according to the symmetric analysis,the horizontal wind field and wind vertical section of the developed mid-level vortex are well symmetric while those of the undeveloped one are less symmetric.Meanwhile,weak wind vertical shear help the developed mid-level vortex to establish a warm core in upper-and mid-levels of the troposphere.On the other hand,according to the balance analysis,better balance between wind and pressure is shown in the mid-and lower-levels of the troposphere of the developed mid-level vortex than in those of the undeveloped vortex.Third,positive anomaly of potential vorticity is enhanced and developed in the vertical direction of the developed vortex.However,the undeveloped vortex weakens with a weak positive anomaly. 展开更多
关键词 South China Sea area tropical cyclone genesis and development mid-level vortex structural characteristics
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Structural Characteristics of the Suoluogou Gold Deposit in Muli County, West Sichuan Province 被引量:1
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作者 NIE Fei FAN Wenyu +3 位作者 LIU Shusheng ZHU Huaping YANG Yongfei SHI Hongzhao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第5期1773-1774,共2页
The Suoluogou gold deposit in Muli County of Sichuan Province is located in the southern section of the Ganzi- Litang suture zone (Figs. la, b), which is the largest gold deposit discovered in this suture zone in re... The Suoluogou gold deposit in Muli County of Sichuan Province is located in the southern section of the Ganzi- Litang suture zone (Figs. la, b), which is the largest gold deposit discovered in this suture zone in recent years. At present, the exploration of the Suoluogou gold deposit is still in progress, and the amount of resource is increasing. 展开更多
关键词 NEE structural characteristics of the Suoluogou Gold Deposit in Muli County
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Structural Characteristics of Semen coicis Resistant Starch and Its Effect on the Proliferation of Bifidobacterium bifidum 被引量:2
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作者 包辰 曾红亮 +4 位作者 张怡 卢旭 张龙涛 黄灿灿 郑宝东 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2017年第3期511-521,共11页
Semen coicis resistant starch is a type of starch which has undergone retrogradation. In this study,the structural characteristics of Semen coicis native starch,high-amylose maize starch,and heat-moisture treated Seme... Semen coicis resistant starch is a type of starch which has undergone retrogradation. In this study,the structural characteristics of Semen coicis native starch,high-amylose maize starch,and heat-moisture treated Semen coicis resistant starch were investigated. The field emission scanning electron microscopy results indicated that compared to Semen coicis native starch and high-amylose maize starch,the surface of heat-moisture treated Semen coicis resistant starch was rough and full of irregular layered strips. The Fourier transform infrared spectroscopy measurements indicated the degree of ordered structure values of Semen coicis native starch,high-amylose maize starch,and heat-moisture treated Semen coicis resistant starch are 1.355,1.372,and 1.410,respectively,and the degree of double helix values is 1.931,1.942,and 2.027,respectively,indicating that the degree of ordered structure and double helix structure of heat-moisture treated Semen coicis resistant starch is both higher than those of Semen coicis native starch and high-amylose maize starch. ^(13) C nuclear magnetic resonance spectroscopy showed that Semen coicis native starch and high-amylose maize starch exhibited A-type crystal structures,while heat-moisture treated Semen coicis resistant starch displayed B-type crystal structures. The relative crystallinity of Semen coicis native starch,high-amylose maize starch,and heat-moisture treated Semen coicis resistant starch is 76.41,85.36,and 87.25,respectively,and the percentages of amorphous region are 5.78,4.72,and 4.39,respectively. Additionally,heat-moisture treated Semen coicis resistant starch could increase the proliferation of Bifidobacterium bifidum more than Semen coicis native starch or high-amylose maize starch. Bifidobacterium bifidum displayed a higher tolerance under simulated gastrointestinal tract conditions such as low p H,bile acid,pepsin,and trypsin in heat-moisture treated Semen coicis resistant starch medium than in Semen coicis native starch or high-amylose maize starch media. 展开更多
关键词 Semen coicis resistant starch structural characteristics
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Structural Characteristics of Rapidly Quenched Al-Si Alloys
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作者 Lin LIU(Institute of Solid State Physics, Academia Sinica, Hefei, 230031, China)Yuanda DONG(Dept. of Metallurgy and Materials, Shanghai University of Technology, Shanghai, 200072, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1994年第3期232-234,共3页
The structure of rapldly quenched Al-Si alloys (1 and 4 wt-%Si) was systematically studied by optical and transmission electron microscopy (TEM ) as welI as X-ray djffractjon (XRD). ExperimentaIresults show that rapid... The structure of rapldly quenched Al-Si alloys (1 and 4 wt-%Si) was systematically studied by optical and transmission electron microscopy (TEM ) as welI as X-ray djffractjon (XRD). ExperimentaIresults show that rapid solidification refines the grain size. extends the solid solubility of Si in Al and Introduces a high density ot defects which exist in the forms of vacancies, dislocations and dislocation loops. etc.. The decomposition process of the alloys was fol lowed by using differential scanning calorimeter (DSC) and the activation energy for precipitation of Si was obtained through Kissinger analysis. The precipitation behaviour of Supersaturated Si in both samples was further examined by TEM. It was found that Si mainly precipitated inside the grains in Al-1 wt-%Si alloy. while in Al-4 wt-%Si alloy. nearly all the Si precipitates distributed along the grain boundaries. This may be due to the structure difference between the alloys in as-quenched state 展开更多
关键词 AL SI structural characteristics of Rapidly Quenched Al-Si Alloys
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The Structural Characteristics of Side-Opening Costumes during the Republic Period of China
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作者 亓延 范雪荣 崔荣荣 《Journal of Donghua University(English Edition)》 EI CAS 2011年第6期632-635,共4页
The structural characteristics of Chinese side-opening costumes during the Republic Period of China were investigated.By measuring and recovering the physical structures of side-opening costume objects from the Folk C... The structural characteristics of Chinese side-opening costumes during the Republic Period of China were investigated.By measuring and recovering the physical structures of side-opening costume objects from the Folk Costumes Biography Museum of Jiangnan University,three structural characteristics were analyzed.These structural characteristics show that most of the side-opening costumes during the Republic Period of China remain traditional Chinese costume structures.The general structural characteristics of side-opening costumes are concluded and the structural cutting methods can inspire current designs as well as provide useful references for contemporary fashion designers. 展开更多
关键词 structural characteristics side-opening costume Republic Period of China structural wholeness
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Structural characteristics and hydrocarbon accumulation inBashituo area, Tarim Basin
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作者 GUO Yiru YU Minghui +3 位作者 LI Zongyu BAYAN Xianmutihan JIA Yudong WANG Xinyu 《Global Geology》 2021年第3期154-159,共6页
According to well logs, core, seismic and other geological data, the authors studied the tectonic evolution stages, trap formation stages, fault and fracture development in the Bashituo area, and furthermore, analyzed... According to well logs, core, seismic and other geological data, the authors studied the tectonic evolution stages, trap formation stages, fault and fracture development in the Bashituo area, and furthermore, analyzed the time of hydrocarbon accumulation, hydrocarbon migration pathways and related controversial issues in the study area. It is believed that the tectonic evolution in the study area can be divided into three stages, namely Late Hercynian, the Early Himalayan and the Late Himalayan. In the Late Hercynian, tectonic movement led to folding and faulting, resulting in the embryonic form of anticlinal traps. In the Early Himalayan, affected by both tectonic movement and transformation, deep faults reactivated and cut through the Lower Tertiary strata. After the Early Himalayan tectonic movement, faulting stopped and no vertical migration pathway was available . Then hydrocarbon migrated laterally along the sand bodies in the Bachu Formation and accumulated in the Carboniferous reservoirs. However, the Carboniferous accumulation was formed late, and the tectonic movement was weak at the Late Himalayan, and faults were underdeveloped, so the reservoirs in the deep Bachu Formation were not disturbed. 展开更多
关键词 Tarim Basin Bashituo hydrocarbon accumulation structural characteristics tectonic evolution
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Structural Characteristics and Risks of China's Economic Transformation and Paths to Efficiency Improvement
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作者 中国经济增长前沿课题组 Yuan Fuhua +1 位作者 Zhang Ping Liu Xiahui 《China Economist》 2014年第3期38-53,共16页
Based on the expanded growth accounting framework,this paper discussed the structural characteristics of China's economic transformation and its related issues and came up with the following conclusions:(1) China&... Based on the expanded growth accounting framework,this paper discussed the structural characteristics of China's economic transformation and its related issues and came up with the following conclusions:(1) China's economic growth has six structural characteristics-- demographic transition,industrial productivity redistribution,income distribution adjustments,increasing urbanization,decreasing capital efficiency and little room for total factor productivity improvement.These factors together may cause a slowdown in economic growth.(2) The risk of economic slowdown in China's economic transformation may be due to the readjustment of income distribution,excessive ineffective investment,increasing economic leverage ratio and fast growing service sector of industrial structure.(3) In response to the potential risks of China's economic slowdown,improving capital efficiency should be the focus of our policy.To establish an inefficient-enterpriseclearing mechanism as well as deepening the reform of corresponding system is the only way to a steady economic growth in the future. 展开更多
关键词 structural characteristics risks of the transition uniformity in convergence capital efficiency
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Simulation of Structural Characteristics and Depth Filtration Elements in Interconnected Nanofibrous Membrane Based on Adaptive Image Analysis
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作者 Mohammad Kazemi Pilehrood Pirjo Heikkila Ali Harlin 《World Journal of Nano Science and Engineering》 2013年第1期6-16,共11页
Due to their unique structural features, electrospun membranes have gained considerable attention for use in applications where quality of depth filtration is a dominant performance factor. To elucidate the depth filt... Due to their unique structural features, electrospun membranes have gained considerable attention for use in applications where quality of depth filtration is a dominant performance factor. To elucidate the depth filtration phenomena it is important to quantify the intrinsic structural properties independent from the dynamics of transport media. Several methods have been proposed for structural characterization of such membranes. However, these methods do not meet the requirement for the quantification of intrinsic structural properties in depth filtration. This may be due to the complex influence of transport media dynamics and structural elements in the depth filtration process. In addition, the different morphological architectures of electrospun membranes present obstacles to precise quantification. This paper seeks to quantify the structural characteristics of electrospun membranes by introducing a robust image analysis technique and exploiting it to evaluate the permeation-filtration mechanism. To this end, a nanostructured fibrous network was simulated as an ideal membrane using adaptive local criteria in the image analysis. The reliability of the proposed approach was validated with measurements and comparison of structural characteristics in different morphological conditions. The results were found to be well compatible with empirical observations of perfect membrane structures. This approach, based on optimization of electrospinning parameters, may pave the way for producing optimal membrane structures for boosting the performance of electrospun membranes in end-use applications. 展开更多
关键词 Nanofibrous Membrane Image Analysis Local Criteria structural characteristics Pore Interconnectivity Depth Filtration
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Study of Structural Characteristics of Cellulose Esters with Different Degrees of Substitution
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作者 Michael Ioelovich 《Organic Polymer Material Research》 2022年第1期38-43,共6页
In this article,structural characteristics of amorphous mono-,di-,and tri-substituted esters of cellulose have been studied.These esters were synthesized under homogenous conditions using anhydrides of various aliphat... In this article,structural characteristics of amorphous mono-,di-,and tri-substituted esters of cellulose have been studied.These esters were synthesized under homogenous conditions using anhydrides of various aliphatic acids.The specific gravity of the highly substituted samples was measured by a pycnometric method in the aqueous medium.To calculate the molar,Van der Waals,and free volumes,as well as the packing coefficient of amorphous esters the method of additive contributions of partial volumes of atoms and atom groups in the volumes of polymers was used.Based on the molar volume,also specific gravity of cellulose esters was calculated.The coincidence of calculated and experimental characteristics was shown.In addition,the relationship between glass transition temperature and free volume was found for the esters.The theoretical equations were derived,which provide predicting the structural characteristics of cellulose esters with different degrees of substitution. 展开更多
关键词 Esters of cellulose Substitution degree structural characteristics STUDY CALCULATIONS
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Structural Characteristics of Vessels in Three Families of Cycadopsida 被引量:2
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作者 Yuyuan Huang Wenbo Liao +3 位作者 Xiaoqing Zhong Lijun Wei Hongda Zhang Yuanfeng Lu 《Journal of Life Sciences》 2010年第7期1-15,共15页
The pinna of Cycasferruginea F.N. Wei (Cycadaceae), pinnas or rachises ofStangeria eriopus (Kune) Baill. (Stangeriaceae), Dioon holmgrenii De Luca, Sabato & Vazq. Torres, Macrozamia moorei F. Muell. ex C. Moore... The pinna of Cycasferruginea F.N. Wei (Cycadaceae), pinnas or rachises ofStangeria eriopus (Kune) Baill. (Stangeriaceae), Dioon holmgrenii De Luca, Sabato & Vazq. Torres, Macrozamia moorei F. Muell. ex C. Moore (Zamiaceae) were macerated and dissociated by Jeffrey's technique, rinsed with water, dehydrated and gold-plated for observation with scanning electron microscopes. The results showed that the pinna and rachis of the leaf tissues of the four cycad species possess many vessel elements and a few tracheid elements in the conducting tissue of the xylem. Annular, spiral, scalariform, pitted and reticulate vessels and some transitional types, including scalariform-pitted, scalariform-reticulate and reticulate-pitted vessels, were observed in the conducting tissues. The characteristics of the vessels of each species, and the evolutionary relation of four genera of cycads were analyzed. Compared with those of angiosperms, the structural characters of vessels of cycad are at the moderate level of evolution and more advanced than some primitive taxa of angiosperms and ferns. Vessels have been discovered in many genera of ferns, which are even more primitive than cycads. In many ferns, only vessel elements, but no tracheids are found in vascular tissue. In the present study, the authors discovered vessels in different genera of three families ofcycads which showed that the existence of vessels in primitive plant taxa is a widespread phenomenon. Vessel elements in vascular tissues of cycads have probably allowed cycads to adapt to various environmental stresses and enabled their persistence over their long evolutionary history. Cycads are the most primitive of the extant seed plants and the widespread existence of vessels in the group has broad implications for plant systematics, evolution and comparative morphology. 展开更多
关键词 ADAPTABILITY CYCADS EVOLUTION structural characteristic VESSEL scanning electron microscopes.
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Structural Characteristics and Evolution of Jurassic Basins in the East of Middle Qilian Block 被引量:1
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作者 郑孟林 李明杰 +2 位作者 曹春潮 张勇军 徐世陆 《Journal of China University of Mining and Technology》 2003年第1期35-39,共5页
Structural characteristics of the Jurassic basins of Xining, Minhe, and Xiji in the east of middle Qilian were researched based on the data obtained by gravitational, magnetic, and seismic methods. The result shows th... Structural characteristics of the Jurassic basins of Xining, Minhe, and Xiji in the east of middle Qilian were researched based on the data obtained by gravitational, magnetic, and seismic methods. The result shows that each of these three basins is an independent structural unit with a NW strike and being separated by upheavals. Two groups of faults with NW and NE directions are developed in the basin, which controls the formation and evolution of the (Jurassic basins). The NW faults are the main ones while the NE faults are the secondary for controlling the sedimentation. Of the three basins, the Minhe basin is the favorable prospecting area. 展开更多
关键词 east of middle Qilian Jurassic basin structural characteristic EVOLUTION prospecting of oil and gas
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Effect of structural characteristics distribution on strength demand and ductility reduction factor of MDOF systems considering soil-structure interaction
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作者 Behnoud Ganjavi 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2012年第2期205-220,共16页
It is known that structural stiffness and strength distributions have an important role in the seismic response of buildings. The effect of using different code-specified lateral load patterns on the seismic performan... It is known that structural stiffness and strength distributions have an important role in the seismic response of buildings. The effect of using different code-specified lateral load patterns on the seismic performance of fixed-base buildings has been investigated by researchers during the past two decades. However, no investigation has yet been carried out for the case of soil-structure systems. In the present study, through intensive parametric analyses of 21,600 linear and nonlinear MDOF systems and considering five different shear strength and stiffness distribution patterns, including three code-specified patterns as well as uniform and concentric patterns subjected to a group of earthquakes recorded on alluvium and soft soils, the effect of structural characteristics distribution on the strength demand and ductility reduction factor of MDOF fixed-base and soil-structure systems are parametrically investigated. The results of this study show that depending on the level of inelasticity, soil flexibility and number of degrees-of-freedoms (DOFs), structural characteristics distribution can significantly affect the strength demand and ductility reduction factor of MDOF systems. It is also found that at high levels of inelasticity, the ductility reduction factor of low-rise MDOF soil-structure systems could be significantly less than that of fixed-base structures and the reduction is less pronounced as the number of stories increases. 展开更多
关键词 soil-structure interaction MDOF systems structural characteristic distribution inelastic behavior strength demand ductility reduction factor
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Comparative analysis of structural characteristics and cardiomyocyte protective effects of glucomannan extracted from Bletilla striata using varied methods
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作者 Feng Pan Nan Yang +5 位作者 Guoyong Ruan Changyan Yu Jianbo Yang Dongxue Suo Ying Qin Yun Liu 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2024年第8期686-704,共19页
Doxorubicin(DOX)is a widely employed tumor therapy,yet its substantial toxic side effects pose a considerable challenge.Bletilla striata has demonstrated efficacy in preventing and treating these toxic side effects in... Doxorubicin(DOX)is a widely employed tumor therapy,yet its substantial toxic side effects pose a considerable challenge.Bletilla striata has demonstrated efficacy in preventing and treating these toxic side effects in clinical practice,with polysaccharides identified as the principal active component.In the present study,16 fractions of B.striata polysaccharides(BsPs)were extracted using diverse methods,including hot-water extraction(HWE),ultrasonic-assisted extraction(UAE),enzyme-assisted extraction(EAE),dilute acid-water extraction(ACWE),and dilute alkali-water extraction(ALWE).These extractions were subsequently precipitated at final ethanol concentrations of 80%and 95%,respectively.The investigation encompassed yields,total carbohydrate content(TCC),total protein content(TPC),preliminary structural properties,and anti-DOX myocardial cytotoxic activity.Results indicated that the extraction method significantly influenced the physicochemical properties,associated functional properties,and anti-DOX myocardial cytotoxic activity of BsPs.HWE and UAE yielded higher BsPs quantities.The relative molecular weight(RMW)distribution of BsPs differed notably between HWE or UAE,EAE,ACWE,and ALWE.The RMW of primary BsPs obtained from HWE and UAE(1.9×10^(7)-1.7×10^(7) Da)exceeded that from EAE(7.5×10^(3)-2.8×10^(4) Da)and ALWE(5.1×10^(4)-1.7×10^(4) Da),with smaller molecular weights primarily precipitated by higher ethanol concentrations.BsPs were composed of Man and Glu,with partial fractions containing small amounts of Gal or Ara,displaying varying molar ratios.Notably,BsPs from ACWE exhibited the most significant structural differences,lacking 1,4-α-D-Glcp and a triple-helical structure.Furthermore,BsPs obtained from HWE,UAE,and EAE demonstrated heightened anti-DOX myocardial cytotoxic activity compared to other methods.This study underscored the influence of extraction methods on BsPs’structure and myocardial protective activity,offering a foundation for exploring structural diversity and employing specific extraction methods to extract polysaccharides with robust myocardial protective properties efficiently. 展开更多
关键词 Bletilla striata(Thunb.)Rchb.f. POLYSACCHARIDE Extraction methods structural characteristics Myocardial protection
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Characteristics of geological structures in Shiling and Zhuanshanhu areas of Yehe Uplift,NE China
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作者 GUAN Yue YU Yinghua +1 位作者 ZHANG Yaxiong YUAN Hongqi 《Global Geology》 2024年第2期105-120,共16页
The basin marginal fault system is the key to understand the formation and evolution of Songliao Basin.In order to investigate the influence of marginal fault system on the structural evolution of Songliao Basin,a com... The basin marginal fault system is the key to understand the formation and evolution of Songliao Basin.In order to investigate the influence of marginal fault system on the structural evolution of Songliao Basin,a comprehensive study was conducted on Shiling Town and Zhuanshanhu area of Yehe Town in Siping City of Jilin Province,where is the southeastern margin of the Songliao Basin and there are a series of well-exposed fault,fold and intrusive bodies belonging to the main marginal fault system of the Songliao Basin known as the Jiamusi-Yitong(Jia-Yi)fault zone.Through profile measurement and field investigation,samples with various lithologies and distinctive features were collected.Detailed field and laboratory works include component and microstructure analysis of these samples,rock-rock contact analysis,main strike measurement and statistics analysis.These data reveal the structural characteristics of the fold,fault and intrusive bodies in the study area.The research results show that the folds are distributed in the Mesozoic strata near the main fault of the eastern branch of the Jia-Yi fault zone,and the folded strata involve the Cretaceous Denglouku and Quantou formations.In addition,the section is dominated by high-angle strikeslip thrust faults.Light-colored veins and dark-colored veins are extensively distributed in the exposed granites.Statistical analysis of joint and fault attitudes in the study area reveals a right-lateral strike-sliping along the main fault.The large-scale right-lateral strike-slip and thrust fault system in Shiling Town occurred in right-lateral transpressive stage in Late Cretaceous.Based on the results above,tectonic evolution sequence in Shiling section of the Jia-Yi fault zone during the Mesozoic can be divided into five stages:Middle Jurassic left-lateral ductile strike-slip stage,Late Jurassic compression stage,Early Cretaceous tension stage,Early Cretaceous extension stage and Late Cretaceous right-lateral transpressive stage.These may have important constraint on understanding the Mesozoic evolution of the Songliao Basin. 展开更多
关键词 Jia-Yi fault structural characteristics evolution sequence Shiling Zhuanshanhu northern segment Tanlu fault
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Structural characteristics and implication on tectonic evolution of the Daerbute strike-slip fault in West Junggar area, NW China 被引量:3
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作者 Kongyou WU Yangwen PEI +4 位作者 Tianran LI Xulong WANG Yin LIU Bo LIU Chao MA 《Frontiers of Earth Science》 SCIE CAS CSCD 2018年第3期555-568,共14页
The Daerbute fault zone, located in the northwestern margin of the Junggar basin, in the Central Asian Orogenic Belt, is a regional strike-slip fault with a length of 400 km. The NE-SW trending Daerbute fault zone pr... The Daerbute fault zone, located in the northwestern margin of the Junggar basin, in the Central Asian Orogenic Belt, is a regional strike-slip fault with a length of 400 km. The NE-SW trending Daerbute fault zone presents a distinct linear trend in plain view, cutting through both the Zair Mountain and the Hala'alate Mountain. Because of the intense contraction and shearing, the rocks within the fault zone experienced high degree of cataclasis, schistosity, and mylonization, resulting in rocks that are easily eroded to form a valley with a width of 300- 500 m and a depth of 50-100 m after weathering and erosion. The well-exposed outcrops along the Daerbute fault zone present sub-horizontal striations and sub-vertical fault steps, indicating sub-horizontal shearing along the observed fault planes. Flower structures and horizontal drag folds are also observed in both the well-exposed outcrops and high-resolution satellite images. The distribution of accommodating strike-slip splay faults, e.g., the 973-pluton fault and the Great Jurassic Trough fault, are in accordance with the Riedel model of simple shear. The seismic and time-frequency electromagnetic (TFEM) sections also demonstrate the typical strike-slip characteristics of the Daerbute fault zone. Based on detailed field observations of well-exposed outcrops and seismic sections, the Daerbute fault can be subdivided into two segments: the western segment presents multiple fault cores and damage zones, whereas the eastern segment only presents a single fault core, in which the rocks experienced a higher degree of rock cataclasis, schistosity, and mylonization. In the central overlapping portion between the two segments, the sediments within the fault zone are primarily reddish sandstones, conglomerates, and some mudstones, of which the palynological tests suggest middle Permian as the timing of deposition. The deformation timing of the Daerbute fault was estimated by integrating the depocenters' basinward migration and initiation of the splay faults (e.g., the Great Jurassic Trough fault and the 973-pluton fault). These results indicate that there were probably two periods of faulting deformation for the Daerbute fault. By integrating our study with previous studies, we speculate that the Daerbute fault experienced a two-phase strike-slip faulting deformation, commencing with the initial dextral strike-slip faulting in mid-late Permian, and then being inversed to sinistral strike-slip faulting since the Triassic. The results of this study can provide useful insights for the regional tectonics and local hydrocarbon exploration. 展开更多
关键词 Daerbute fault structural characteristics deformation timing West Junggar
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