最新刊期
卷 61 ， 期 2 ， 2022
- 摘要：Enzymatic biocatalysis is an important signal transduction and metabolic pathway in the cellular microenvironment， which can maintain the orderly communication between complex cell networks and allow the immediate signals feedback. It has an important application prospect in the fields of biosensors， catalysis and nanomedicine etc. However， the inherent fragility of enzymes greatly limits their maneuverability and practicability in extracellular environment. Rational design of metal-organic frameworks （MOFs） carriers to constraint and immobilize the enzymes is the forefront approach to improve the enzymes’ stability. In this paper， three immobilization strategies including surface attachment， osmosis-based entrapment and in-situ embedment methods are reviewed， with emphasis on the application range and stabilization characteristics of different immobilization modes. In addition， a brief outlook on the development of the immobilization research of enzyme@MOFs is also presented.关键词：enzyme immobilization;metal-organic framework;biocatalysis
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发布时间：2023-11-01
Invited review
- 摘要：Based on the daily precipitation data of 192 meteorological observation stations in South China during 1961-2018， the regional rainstorm processes in winter in South China are evaluated objectively and quantitatively， and the annual rainstorm intensity index and regional strong winter rainstorms are determined. Based on the reanalysis of NCEP/NCAR data， combining with other methods， the climate background of the severe winter rainstorm in South China and the weather characteristics of the regional rainstorm processes are studied. The common characteristics of climate and weather are as follows： The westerly jet strengthens in the upper troposphere in winter in the Indo-China Peninsula and the South China Sea， the East Asian Trough weakens in the middle layer， the subtropical high over the Western Pacific strengthens， the southern branch trough and southerly current at the lower level strengthen， and the water vapor convergence strengthens. The difference is presented in the heavy rain process at the daily scale in South China in winter， in which the wave train structure of the northern hemisphere subtropical abnormal circulation is very obvious， similar to the ‘remote correlation of silk road’ in the upper troposphere of the northern hemisphere in summer circulation characteristics， but the center of oscillation is southerly in winter than it in summer. For the strong winter rainstorm year， the SST is higher in the equatorial Middle East Pacific， the tropical Indian Ocean， and the South China Sea， while it is lower in the tropical western Pacific from July to December in last year， which was conducive to the occurrence of winter rainstorm in South China. Therefore， the seasonal scale （particularly in winter） circulation and early SST reflect the climate background of the regional rainstorm in South China， while the daily scale atmospheric circulation anomaly can better reflect its abnormal weather characteristics.关键词：regional rainstorm process;intensity;atmospheric circulation;SST;winter;South China
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发布时间：2023-11-01 - 摘要：Focusing on the emergence， dispersion， development and decline of jadeite in the Neolithic Age in Europe， this paper analyzes the achievements of alpine jadeite of the Neolithic Age studied by European scholars in the past two decades， and summarizes their geographical distribution range and types. Taking the large jadeite axes as an object， which were mainly unearthed in Morbihan Bay and Carnac area during 6 000 BC-3 000 BC， with comprehensive consideration of the influence of Paleolithic technology， the impact of new resources and the evolution of mainstream culture， this paper interprets the reasons for the various shapes and multiple dispersion routes of European large jadeite axes. It also discusses the functions that the large European jadeite axes can be used as a tribute to worship the supernatural environment， power mark of elite class and funeral rites. Finally， this paper proposes three possible reasons for the disappearance of jadeite axes and suggests the future research directions.关键词：jade axes;jadeite;Neolithic Age;cultural evolution;Europe
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发布时间：2023-11-01 - 摘要：The automatic detection of new construction land can provide a new and effective technical support for the protection of natural resources. Taking Guigang city of Guangxi Province as the research area， this paper proposes an automatic detection method for new construction land based on deep learning and multi-source remote sensing data. Firstly， in training area the high-resolution remote sensing image is performed preprocessing， data augmentation and difference processing to obtain training data. Secondly， deep learning semantic segmentation model（DeepLabv3+）is used for image training， tuning； and then according to the extraction results of the area where remote sensing image（Sentinel-2A） changed， the regions where newly increased construction land might appear are screened in the test area. Finally， the automatic detection results of newly increased construction land under different cropping overlap rates are verified. The results show that：1） In the test area， the higher the cropping overlap rate is， the higher the patches detection accuracy will be； whereas at the same time， the calculation amount of detection and the patches error rate increase. When the cropping overlap rate is 70%， a good balance can be achieved between the detection accuracy， calculation amount and the patches error rate. 2） A cropping overlap rate of 70% delivers 85.16% detection accuracy of the newly increased construction land patches，36.57% misclassification rate，57.23% IoU of the average patches and 74.52% detection area ratio.关键词：deep learning;multi-source remotes sensing data;newly increased construction land;urban and rural planning
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发布时间：2023-11-01 - 摘要：Based on the analysis of weather of the moderate-to-severe haze pollution incidents in Shenzhen from 2008 to 2018， the WRF-Chem model and sensitivity tests were used to quantify the contribution of anthropogenic emission sources from Shenzhen and its surrounding cities （Guangzhou，Dongguan， and Huizhou） to the hazing process in Shenzhen using sensitivity tests， and to reveal the main transport characteristics of the hazing pollution process in the area. The main weather types affecting the process of moderate-to-severe haze pollution in Shenzhen are typhoon peripheral circulation pattern and Continental high （ridge） type， in which Continental high （ridge） type， can be further subdivided into three different types according to the wind field （north-east wind type， wind direction variable type， southerly wind type）. The sensitivity tests of typical pollution cases show that under the typhoon peripheral circulation pattern during hazing pollution process， the local contribution rate of Shenzhen was 40.38%， and the total contribution rate of the surrounding cities was 22.6%. For the three types of Continental high （ridge） pollution processes， Shenzhen's local contribution rates were 21.12%， 53.92%， and 55.41%， while the total contribution rates of the surrounding cities were 6.88%， 10.97%， and 3.44%， respectively. Wind speed and orientation have the most significant impact on transport characteristics. When the wind speed was 3 to 4 m/s， the contribution rate of Shenzhen local sources can reach 50%. When the wind speed was about 6 m/s， the contribution rate of transmission increased significantly while the local contribution rate decreased to 20% to 40%. The contribution of different cities was affected by wind directions. While the dominated wind field of typhoon peripheral circulation pattern haze was mostly northwest， Dongguan and Huizhou's contribution differed， with 15.03% and 1.77%， respectively. In other scenarios， the contributions of these two cities were more consistent， about 1% to 5%. Guangzhou’s contribution to Shenzhen can reach 5.8% with the northwest winds caused by the Typhoon peripheral circulation pattern.关键词：moderate-to-severe haze pollution;transport characteristics;typhoon peripheral circulation pattern;continental high （ridge） type;Shenzhen
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发布时间：2023-11-01 - 摘要：With unique geographical location， Qinling-Daba Mountain area has a fragile and sensitive ecological environment， and the population， resources， and environmental problems in the area have become increasingly prominent. The central Qinling-Daba Mountain area （Hanzhong， Ankang， and Shangluo） is studied to reveal the spatio-temporal evolution characteristics of ecological sensitivity and its influencing factors in the central Qinling-Daba Mountain area by using the data of DEM， land use， and population density of 2000， 2005， 2010， 2015， and 2018， and methods of PSR （pressure-state-response） model， entropy method， and geographical detector. The results show that： 1） the areas with high ecological sensitivity were mainly located in Hantai District， Luonan County， and Zhenping County， among them， Zhenping County was the most sensitive area in the study period. 2） The ecological sensitivity of the central Qinling-Daba Mountain area was in a downward trend， and the change of the most sensitive area was more significant， from 12.35% in 2000 to 2.91% in 2018. 3） By comparing the three cities， we found that in Hanzhong， the q value of the population density of pressure index， the elevation of state index， and the maximum patch index of forest land of response index were large， forming the main effects on ecological sensitivity； in Ankang， the distance from the water was the dominant factor of the pressure index， the main driving factor of the state index was elevation， and the main influencing factor of response index was the degree of fragmentation of cultivated land； in Shangluo， the q value of the population density of pressure index， the elevation of state index and the maximum patch index of forest land of response index were large and predominant. The results have significance for ecological planning and sustainable development in the central Qinling-Daba Mountain area.关键词：the central Qinling-Daba Mountain area;ecological sensitivity;spatio-temporal evolution;influencing factors;geographical detector
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发布时间：2023-11-01 - 摘要：Selaginella tamariscina （Beauv.） Spring and S. pulvinata （Hook. et Grev.） Maxim. are two closely related rosette forming and resurrection spikemoss species widespread in Asia. In this paper， Selaginella orientali-chinensis Ching et C. F. Zhang ex H. W. Wang et W. B. Liao was described and illustrated. This species was closely related to S. tamariscina and S. pulvinata and previously misidentified as S. tamariscina. By the gross morphological and molecular evidences， we found that this species is easily distinguished from S. tamariscina and S. pulvinata by the absolutely dichotomously branched main stems. Our field works confirmed that this species is widely distributed in southeastern China and mainly inhabits Danxia landforms areas. In some cases， this species shares the same habitats with S. tamariscina. Illustrating the morphological， phylogenetic and distribution characters of this new species would provide new data for the taxonomic studies on the genus Selaginella in the future.关键词：Selaginella;Danxia landforms;morphology;phylogeny;distribution
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发布时间：2023-11-01 - 摘要：Compound Xueshuantong Capsule （CXC）， composed of Notoginseng Radix et Rhizoma， Salviae Miltiorrhizae Radix et Rhizoma， Astragali Radix， and Scrophulariae Radix， has the functions of promoting blood circulation， removing blood stasis， benefiting qi and nourishing yin. This study was designed to analyze the mechanisms of CXC against microcirculation disorders based on the network pharmacology technology. The active components and potential targets of CXC to improve microcirculation was screened by GeneCards， OMIM， TCMSP databases， Venny， and literatures. The PPI network was constructed and the core genes were screened by STRING and Cytoscape. The GO and KEGG pathway were analyzed and the component-target-pathway network was established through DAVID and Cytoscape. The results showed that 41 active compounds and 40 potential targets of CXC were identified. Saponins， flavonoids， tanshinones， salvianolic acids， iridoids， and phenylpropanoid glycosides were the main active compounds. IL6， CCL2， ICAM1， EDN1， Jun， NOS3， PTGS2， VCAM1， MMP9 and TNF were the key targets. The first 20 pathways enriched by potential targets included cardiovascular pathways such as fluid shear stress and atherosclerosis pathway and HIF-1 signaling pathway； inflammatory pathways such as complement and coagulation cascades pathway and TNF signaling pathway， neuroactive pathways such as Neuroactive ligand-receptor interaction， and Diabetes related pathways such as AGE-RAGE signaling pathway. This study showed that CXC might play an important role in improving microcirculation by regulating the targets and pathways of cardiovascular， inflammation， immune， and neuroactivity， thus to affect the angiogenesis， vasodilation， proliferation of vascular smooth muscle and microcirculation blood flow.关键词：Compound Xueshuantong Capsule （CXC）;network pharmacology;microcirculation;mechanism
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发布时间：2023-11-01 - 摘要：DNA methyltransferase 1 （DNMT1） is one of the key enzymes for genomic DNA methylation and plays an important regulatory role in the growth and development of organisms. We obtained a cDNA sequence of DNMT1 from the transcriptome of Sogatella furcifera， and then analyzed its structure. The transcript has an open reading frame of 4 524 bp in length containing an initiation codon ATG and a termination codon TGA. The protein encoded has the typical structure of DMAP binding domain， replication foci targeting sequence， CXXC zinc finger domain and Polybromo homology domain located at the N-terminal and Dcm domain located at the C-terminal. Comparing the sequence with the whole genome sequence of S. furcifera， the DNMT1 gene was found locating on chromosome 3 of S. furcifera， with a full length of 22 567 bp， containing 18 exons and 17 introns. The gene was mainly expressed in the abdomen of the white-backed planthopper， and the expression level in female adults was significantly higher than that in male adults， up to 4.3 times. This study could enhance the understanding of the specific structure and biological function of insect DNMTs and provide a theoretical basis for the exploration of new methods or pathways for the control of planthopper.关键词：DNMT1;Sogatella furcifera;open reading frame;gene expression
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发布时间：2023-11-01 - 摘要：Molecular dynamics （MD） simulations were performed to study the interfacial structure and dynamics of acetonitrile （ACN） on the graphene electrode surface in supercapacitors. The influence of cluster modification and charge densities on the structure and dynamics of ACN have been analyzed through density distribution， orientation distribution and diffusion analysis. Simulation results indicate that electrode modification with clusters will induce strong steric hindrance that impedes the adsorption and diffusion of ACN， while charges on the electrode will give rise to reorientation of ACN molecules that further affect their transport. Our simulations have revealed the microscopic mechanism of ACN-electrode interactions and would be helpful for understanding the distribution of solvent in supercapacitors under working conditions.关键词：graphene;acetonitrile;supercapacitors;molecular dynamics
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发布时间：2023-11-01 - 摘要：The LCL filter is widely used in grid-connected inverters because of its superior suppression effect on high frequency switching noise of power devices， but the application of this filter is limited by the system resonance caused by its LCL structure. The second differential term of the grid-connected current is introduced to suppress the natural resonance frequency of the LCL filter in the inner loop of the inverter system based on virtual impedance， and the outer loop directly controls the grid-connected current， thus forming a double closed-loop control system. This method has made improvements on the basis of traditional active damping schemes， which reduces the number of sensors and thus reduces the cost of the inverter. Due to the reduction of the feedback state quantity， the system is prone to oscillating when the grid voltage contains harmonic components， which weaken the anti-interference ability of the inverter system. To solve this problem， this paper improves the virtual impedance-based grid-connected inverters with a full feedforward function of grid voltage. This strategy can reduce the total harmonic distortion （THD） of the grid current and improve the grid-connected power factor in the case of grid voltage distortion. The simulation results prove the effectiveness of the proposed control strategy.关键词：LCL filter;virtual resistance;active damping;voltage feedforward
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发布时间：2023-11-01 - 摘要：Electroimpedance tomography (EIT) is a typical inverse problem in karst cave detection, which is ill-posedness and very sensitive to measurement error. In order to overcome the defect of ill-posedness， the regularization method should be introduced. In this paper， we mainly consider Tikhonov regularization and sparse regularization. Then， two different methods-linear approximate direct solving method and iterative solution method is used to solve the problem. And， EIT is used to detect underground karst caves, because of some advantages， such as relatively simple equipment， convenient data acquisition and insensitive to material inhomogeneity.Finally， a numerical example is given to compare the effects of these methods.关键词：EIT;cavity detection;Tikhonov regularization;sparse regularization;sensitivity analysis
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发布时间：2023-11-01 - 摘要：Due to the characteristics of cellular signaling， such as sparsity and spatial uncertainty， it is difficult to identify the location of workplace and residence. At the same time， the current cellular signaling residence and workplace identification algorithm is an insufficient basis and unknown effectiveness for the key elements affecting the identification results， such as time rules and spatial aggregation distance. In view of the above difficulties， this paper proposes a comprehensive decision-making algorithm based on celluar signaling track point identification， which eliminates the spatial uncertainty of mobile signaling and effectively defines the space-time boundary of the stay area. Based on the recognition of stay points， the distribution characteristics of stay points in each period are extracted， and the information entropy of each period is calculated to measure the possibility that the period belongs to the residence and workplace period， and the weighted value of the period is given in this paper. By discretizing the arrival and departure time axis of any semantic stay point， the stay time slot of semantic stay point is combined， and the characteristics of stay time slot are reflected by the time slot weight. Based on the characteristics of the stay time slot and stay time， a comprehensive decision matrix of residence and workplace is constructed to identify the most likely semantic stay point as the residence and workplace， and the cellular signaling with stay tag is used to verify the effectiveness of the algorithm.关键词：cellular signaling;identification of cellular signaling track points;information entropy;residence and workplace;decision matrix
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发布时间：2023-11-01 - 摘要：In practical engineering， sulfate-rich cement saline soil is prone to produce ettringite crystals， leading to the expansion and destruction of cement soil. Sodium hexametaphosphate can inhibit the nucleation reaction of ettringite in a solution environment without impurity ions. However， its inhibitory effect on ettringite in a complex sulfate cement soil environment is still unclear. In this article， the influence of different sodium hexametaphosphate content on the nucleation and growth of ettringite crystals in cement soil in different sulfate environments （soaked or incorporated） was analyzed by means of scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results show that the addition of sodium hexametaphosphate cannot effectively inhibit the nucleation of ettringite crystals in sulfate-rich cement soil， but it can effectively inhibit the size growth of ettringite crystals.关键词：cement soil;ettringite;sulfate attack;inhibitor;microscopic morphology
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发布时间：2023-11-01 -
Research on equivalent static stiffness of arch foot of continuous rigid frame composite arch bridge
摘要：In full-bridge finite element modeling analysis of continuous rigid frame composite arch bridge， the rational establishment of the arch unit is very important. In order to investigate equivalent static stiffness of arch foot of continuous rigid frame composite arch bridge， the local entity model and local truss model of the arch foot are established by Midas Civil and Midas FEA by taking Jiangkengnei Bridge of Fuzhou-Xiamen Railway as the research object. The displacement of arch rib is compared and analyzed. Finally， the influence of the equivalent static stiffness of arch foot on force performance of the bridge is analyzed. The results show： the reasonable equivalent static stiffness of the arch of continuous rigid frame composite arch bridge is 15 ~ 25 times the stiffness of the arch rib. With the consideration of the equivalent static stiffness， the force of hanger rods of the bridge near the arch is significantly reduced. The maximum internal force is 35.3 kN， and the force of hanger rods near the middle span is increasing， but it’s not obvious； under the main force combination， the deflection of the arch ribs decreases in the range of 0 ~1/4- 4
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发布时间：2023-11-01 - 摘要：Taking the tunnel under the station of Hefei Metro Line 5 as object， considering the characteristics of expansive soil， such as dilatancy, crevice and et al， and the construction scheme on site，a risk assessment model based on “overlaying metro station deformation and failure” as the top event is builded.The probability of incident and the importance of influencing factors are determined. Then, the risk of damage to the overlaying metro station is evaluated and risk lever is rated by the fuzzy AHP method. The results show that this paper provides a complete quantitative evaluation system for the construction risk assessment of underpass of an existing subway station.关键词：expansive soil;underpass;risk assessment;fuzzy AHP method
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发布时间：2023-11-01 - 摘要：Based on the finite element analysis of the nonlinear shear deformation of the studs and the stress analysis of the partition, the shear deformation of the studs in two parts of the steel-concrete composite beam with box section is studied. The results show that the horizontal shear capacity of steel-concrete composite box girder is provided by web flange bolts. The installation of baffle flange bolts cannot improve the shear connection degree of composite beams. Removing the flange stud of the diaphragm can relieve the force on the diaphragm. The aboved conclusion provide a theoretical basis for reducing the stiffener of the diaphragm.关键词：steel-concrete composite;composite box girder;negative bending moment;slip
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发布时间：2023-11-01 - 摘要：Based on the ozone（O3） observation data of 14 monitoring stations in Jiaxing city from 2014 to 2018， the characteristics of the temporal variations and spatial distribution of O3 were analyzed，then the correlation between temperature， humidity and O3 concentration were discussed. Results indicate that the number of days that the air quality index （AQI） exceeded the standard per year decreased over the past five years. However， the proportion of days that the O3 exceeded the standard gradually increased， from 43 % in 2014 to 64 % in 2018. O3 concentration in Jiaxing City had seasonal variations with the order of summer>spring>autumn>winter， and the O3 pollution mainly occurred between late spring and early autumn. Correspondingly， the number which days of exceeding the O3-8h standard from April to September reached 8 days per month or more. Spatially， the O3 pollution in Jiaxing was mainly distributed in the central and northern areas of the city. At the Qinghe primary school site， the fraction of the 1h-O3 concentrations that exceeded 200 µg/m3 was the highest among all stations， and the hourly peak O3 concentration-area lasted the longest from July to September. The temperature and relative humidity were significantly correlated with ozone concentrations. O3 concentrations as well as the ratios of exceeding the standard increased significantly when temperature was above 33 ℃ or the relative humidity was lower than 50 %.关键词：ozone;over-standard rate;temperature;relative humidity;Jiaxing city
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发布时间：2023-11-01 - 摘要：During the construction process of steel truss arch bridges， it is difficult to calculate the forces of the buckle cable for consideration of both uncertainties and control criteria. In order to solve these problems， a reliability-based buckle cable force optimization method based on multi-objective optimization method is proposed. This method uses support vector regression model as the agent model to fit the relationship between random variables and each target variable， combining with First Order Second Moment method to solve the reliability. Multi-objective particle swarm algorithm based on adaptive grid method is used to optimize the target variables. Compared with the single objective optimization method，this method considers more comprehensive factors. The Pareto optimal solution can be further screened by decision makers based on experience. A plane truss structure is taken as an example to verify the effectiveness of the method. Several reliability calculation methods are compared in terms of advantages and disadvantages. This method is applied to a steel trussed arch bridge with a span of 70 m+240 m+70 m. Both the alignment and stress is optimized， and the reliability of buckle cable is within an acceptable range by optimizing the buckle cable forces.关键词：steel truss arch bridge;reliability;multi-objective optimization;support vector regression;particle swarm optimization
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发布时间：2023-11-01 - 摘要：The existence for periodic solution of Kirchhoff-type second-order discrete system with variable exponent is studied. Some results for existence of periodic solutions are obtained by using the least action principle and the saddle point theorem in critical point theory.关键词：periodic solution;discrete p（k）-Laplacian operator;variable exponent;Kirchhoff problem
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发布时间：2023-11-01 - 摘要：Aiming at the problem of boundary tracking of water pollution diffusion concentration， the geostatistical spatial interpolation is performed to reconstruct the pollution diffusion concentration field through random sampling and comparison of different fitting parameters. According to the fitting parameters of reconstructing the concentration field， the model predictive control method is used to optimize the movement trajectory of water surface mobile robot， and control the movement of mobile robot to track the pollution diffusion boundary. The simulation results show that the method can accurately predict the concentration field distribution， and make the mobile robot quickly converge to the established concentration boundary， which verifies the effectiveness of the method.关键词：concentration field;interpolation;model predictive control;concentration boundary
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发布时间：2023-11-01 - 摘要：The stability of solution set mapping for parameter set-valued optimization problems via improved sets in real normed vector space is discussed. The upper semi-continuity and lower semi-continuity of level set-valued mappings via improved sets
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发布时间：2023-11-01
Research articles
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