Table of Content

    25 January 2020, Volume 59 Issue 1
    Progress of the study on Landau-Ginzburg A model
    FAN Huijun, JIANG Wenfeng, YANG Dingyu
    2020, 59(1):  1-8.  doi:10.13471/j.cnki.acta.snus.2020.01.001
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    A brief introduction of Landau-Ginzburg A model (LG Amodel) in homological mirror symmetry is given. Firstly, a short review of the general picture of the homological mirror symmetry is given. Then the background of Landau-Ginzburg model and its role in homological mirror symmetry are discussed. Finally,  a brief introduction of our recent work on the Fukaya category of LG model is included. Both mathematical and physical backgrounds are tried to include in this introduction as much as posible.

    Relative and generalized Tate cohomology with respect to balanced pairs
    ZHANG Chunxia
    2020, 59(1):  9-14.  doi:10.13471/j.cnki.acta.snus.2020.01.002
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    The relative and generalized Tate cohomology with respect to balanced pairs are studied. An Avramov-Martsinkovsky type exact sequence is obtained.

    Analysis, linear feedback synchronization and circuit realization of a hyperchaotic Tangs system
    GAO Zhizhong
    2020, 59(1):  15-23.  doi:10.13471/j.cnki.acta.snus.2020.01.003
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    In order to generate complex hyperchaotic, a new fourdimensional Tang hyperchaotic system based on Tang system is built. The phase diagram,bifurcation diagram and Lyapunov exponents spectrum diagram of the system are analyzed by means of numerical simulations.Numerical simulations show that the new systems dynamics behavior can be periodic, quasiperiodic, chaotic and hyperchaotic as the parameter varies. Compared to the previous hyperchaotic, the system possess the large change range with new parameters , and the system changes with  and p show the same dynamic behavior and a certain proportion. Linear controller is designed to realize synchronization of the hyperchaotic system. Results demonstrate that the method is correct and effective. Finally, a corresponding experimental circuit is designed. The hyperchaotic dynamical behavior of the circuit system and synchronization results of the driver system as well as response system are observed by an oscilloscope. The results are basically consistent with those of digital simulation. 

    Quasiperiodic motion of a buckled beam with 1∶3 internal resonance
    XIAO Longjiang, HUANG Jianliang
    2020, 59(1):  24-34.  doi:10.13471/j.cnki.acta.snus.2020.01.004
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    This study investigates nonlinear dynamics of a fixedfixed buckled beam with 1∶3 internal resonance in the first two symmetric modes subject to uniform base harmonic excitation. The Galerkin method is employed to discretize the governing equation, the traditional incremental harmonic balance (IHB) method with single time scale is used to track periodic responses of the buckled beam,and the Floquet theory is used to analyze stability and bifurcation of the solution. It is found that the antisymmetric modes can be excited with increasing the excitation amplitude due to 1∶3 internal resonance, continuously increasing the excitation amplitude, Hopf bifurcation occurs which leads to quasi-periodic motion whose spectrum contains uniformly spaced sidebands around integer multiples of excitation frequency with increasing the excitation amplitude. The IHB method with two timescales is used to investigate quasi-periodic motion, whose solutions are in good agreement with those from numerical integration using the fourth-order Runge-Kutta method.

    Differential variational principle of Herglotz type and a new type of adiabatic invariants in phase space#br#
    XU Xinxin, ZHANG Yi
    2020, 59(1):  35-42.  doi:10.13471/j.cnki.acta.snus.2020.01.005
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    According to differential variational principle of Herglotz type, this paper studies the adiabatic invariants for nonconservative system in phase space. Firstly, the Hamilton canonical equations based upon the generalized variational principle of Herglotz are given. Secondly, by using the invariance of the Hamilton-Herglotz action under the infinitesimal transformations, the new type of exact invariants in phase space are established, and the perturbation of the system with the action of small disturbance is investigated, and a new type of adiabatic invariants of the system are obtained. Thirdly, the inverse theorem is given. In the end of the paper, an example is given to illustrate the application of the results.

    Steadystate heat source identification based on sparse regularization
    PAN Tiancheng, LV Zhongrong, WANG Li
    2020, 59(1):  43-49.  doi:10.13471/j.cnki.acta.snus.2020.01.006
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    The heat source identification problem that aims to identify the spatial locations and strengths of point heat sources and know well about the heat source properties of actual engineering structure in time belongs to the field of Inverse Heat Conduction Problem (IHCP). The heat source identification problem is generally illposed, that is, the identified results are very sensitive to the measurement noise when the measured data is insufficient. In order to overcome the ill-posedness, additional constraints need to be introduced. In this paper, a novel point heat source identification approach based on sparse regularization is proposed where the sparsity of point heat sources in space is mainly considered. Due to the existence of measurement noise, a weak enforcement of measured data through a penalty term is introduced into the objective function. Moreover, to well corporate with the sparse regularization, the alternating minimization is used to iteratively solve the separated variables of temperature and heat source, and the threshold setting method is proposed to quickly and accurately find an appropriate regularization parameter. At last, a numerical example on a twodimensional steadystate case shows that the proposed approach can quickly and accurately identified both the locations and the strengths of heat source and is insensitive to measurement noise.

    Characteristics analysis of PM2.5 and NO2 pollution at Beijing traffic stations during the Spring Festival from 2014 to 2018#br#
    LUO Yinping, CHEN Tong, DING Hui, CHEN Jincai, LIU Yonghong, QU Xinming
    2020, 59(1):  50-63.  doi:10.13471/j.cnki.acta.snus.2020.01.007
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    Based on hourly observation data of PM2.5 and NO2 concentrations at Beijing traffic stations during the Spring Festival from 2014 to 2018, the effects of vehicle emission reduction and fireworks forbidden and the impacts of emissions from fireworks and meteorological conditions on air quality were analyzed by comparing concentration characteristics and ratio of PM2.5 to CO The results showed that characteristics of PM2.5 and NO2 concentrations were different during the Spring Festival. The average PM2.5 concentrations from 2014-2018 were 103.6 μg/m3 and 25.3% higher than those before and after the Spring Festival. Significantly affected by vehicle emission reduction at traffic stations, the NO2 concentration was 53.8 μg/m3 and 19.5% lower than those before and after the Spring Festival. The concentrations of PM2.5 during the Spring Festival was lowest in 2014, and decreased year by year from 2015-2018. The burning of fireworks had relatively greater impacts on PM2.5 than NO2 During the New Years Eve, the maximum contribution of hourly PM2.5 concentration from burning fireworks was 283.4-704.1 μg/m3 Compared with the average of the previous four years, the concentrations of PM2.5 decreased by 25.2% and NO2 reduced by only 2.4%, which implied PM2.5 pollution was improved significantly by the measures of banning fireworks within the Fifth Ring Road in 2018. Under the meteorological conditions unfavorable to atmospheric diffusion, the maximum contribution of PM2.5 concentration during the New Year’s Eve was still 45.0% lower than that of the previous four years, indicating great reduction effect of fireworks prohibition measures. The effect of meteorological conditions on the PM2.5  during the Spring Festival was more significant than those of NO2. The meteorological condition favorable for atmospheric diffusion was the main reason for the great improvement of PM2.5 pollution in 2014.

    Research on damage detection technique of cryogenic tank adiabatic structure using ultrasonic guided waves
    MA Yunlong, GAO Yihang
    2020, 59(1):  64-72.  doi:10.13471/j.cnki.acta.snus.2020.01.008
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    According to the damage and failure mode of the Reusable Launch Vehicle (RLV)cryogenic tank insulation structure, combined with the NDT technology of adiabatic structure debonding,a technical solution of insulating structure debonding detection and monitoring was proposed based on ultrasonic guided waves. Also the adiabatic structure debonding (specimen stage) was detected in the temperature-load combined loading test, while the feasibility of the system was preliminarily measured by principle verification test, which provided support to the design, performance assessment and maintenance of RLV cryogenic tank insulation structure.

    The effect of the pore size and shape on acoustic absorption of porous materials
    2020, 59(1):  71-76.  doi:10.13471/j.cnki.acta.snus.2020.01.009
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    Porous materials are usually used for acoustic absorption applications.Different kinds of pore size and pore shapes were prepared by 3D printing. And the sound absorption properties of them are evaluated by both the numerical calculation using the Comsol Multiphysics software and the experimental measurement as well. It is found that the sound absorption coefficient increases with increasing the title angle of the conical holes, then reaches the maximum value when the pore angle is 45°. A further increase in the title angle of the conical holes lowers the sound absorption coefficient.  Meanwhile, the sound absorption coefficient increases gradually with increasing the pore depth from 2mm to 5mm. However, when the depth of the pores increases from 5mm to 7mm, the sound absorption coefficient doesn't have obvious change anymore.

    Relationship between built environment and bikeshare allocation in the mainland of China
    CAO Xiaoshu, LUO Yi
    2020, 59(1):  77-85.  doi:10.13471/j.cnki.acta.snus.2020.01.010
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    Bikeshare is a green, healthy and flexible mode of transportation. While it benefits local residents, it causes some problems such as resource waste and allocation mismatch. Much research focused on the interaction between built environment and bikeshare in cities, but few studies explore the relationship between built environment and bikeshare allocation at a large scale. In this paper, the relationship between built environment and bikeshare allocation in the mainland of China and how the spatial heterogeneity of bikeshare allocation was affected by built environment variables were studied by using multiple regression analysis and with the Geographically Weighted Regression model, respectively. The results show that: 1) Built environment and bikeshare allocation are correlated. The number of retail salespersons and road density are positively related with bikeshare allocation, while income level and urban area are negatively associated with bikeshare allocation. 2) Bikeshare allocation shows a significant spatial heterogeneity. The number of retail salespersons, road density and income level increasingly affect bikeshare allocation from east to west. The urban area has a negative effect on bikeshare allocation within most cities, and its impact decreases gradually from core to periphery.

    The hydrogen and oxygen isotope characteristics of precipitation and water vapor sources in the lower Dongjiang River reaches, Guangdong Province
    XIE Linhuan, JIANG Tao, CAO Yingjie, LI Kun, TANG Changyuan
    2020, 59(1):  86-95.  doi:10.13471/j.cnki.acta.snus.2020.01.011
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    Atmospheric precipitation is the main input source of the water cycle system, and the stable isotope compositions (δD, δ18O) are greatly influenced by regional meteorological and geographical factors and are very sensitive to environmental changes. Stable oxygen and hydrogen isotope technique is widely used to study the characteristics of the global and local water circulation. The Dongjiang River Basin is located in the Pearl River Delta, China. The monsoon circulation controls the time and space distributions of precipitation by affecting the distribution of water vapor transport field. The lower reaches of the Dongjiang River was taken as the research object to study the mechanism of regional precipitation. Daily precipitation samples were collected in 2017, δD and δ18O were measured and the relationships between δD, δ18O and temperature, precipitation were analyzed. The HYSPLIT backward trajectory model was used to trace water vapor sources and the transport of regional precipitation. The results show that the δD and δ18O values ranged from -105.10‰ to +9.98‰ and -14.80‰ to -0.55‰, respectively, and the annual weighted mean values were -57.88‰ and -8.61‰. Regional Meteoric Water Line was δD=8.60δ18O+16.51(R2=0.99). The maximum δ18O appeared in January, which was -3.47‰, and the minimum value appeared in August, which was -10.17‰. In the monthly scale, δ18O shows “anti-temperature effect” and “quantity effect” The δD and δ18O in precipitation which caused by water vapor in the Pacific Ocean were higher than those in the Indian Ocean. However, the δD and δ18O in precipitation caused by the air masses from the South China Sea changed with the seasons, which weres significantly lower in summer and autumn than those in spring. There was obvious circulation effect of isotope in atmospheric precipitation. 

    Spatial differentiation and aggregation characteristics of ecological security of urban agglomeration in the Pearl River Delta 
    LI Miao, HU Mengmeng, XIA Beicheng
    2020, 59(1):  96-104.  doi:10.13471/j.cnki.acta.snus.2020.01.012
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    The Pearl River Delta (PRD) urban agglomeration is an important part of the Guangdong-Hong Kong-Macao Greater Bay. It is of great significance to study the ecological security and spatial pattern of the PRD urban agglomeration under the background of the national policy of implementing the construction of the Guangdong-Hong Kong-Macao Greater Bay. The ecological security evaluation system of urban agglomeration was constructed in the PRD based on the PSR conceptual model, and the set pair analysis and spatial autocorrelation analysis methods were applied to analyze the spatial heterogeneity and aggregation characteristics of urban agglomeration ecological security. The results show that the PRD is affected by urbanization, and the ecological security level shows an obvious spatial differentiation. The ecological security level of the central area, where it highly urbanized, is significantly lower than that of the peripheral area. The peripheral area forms an ecological barrier to the central area. The level of ecological security has a significant relationship with regional economic development, and the level of ecological security and economic development are negatively correlated in space. The clustering of ecological security in cities shows a “low-high” or “high-low” agglomeration situation. Cities with higher ecological security tend to be adjacent to cities with lower ecological security, showing a complementary spatial pattern. This spatial differentiation and aggregation characteristics have important guiding significance for the future ecological planning, urban ecological construction and ecological management of the urban agglomerations of the PRD and Guangdong-Hong Kong-Macao Greater Bay. 

    The flood disasters in Wushan county based on machine learning algorithm model
    MU Fengyun, YANG Meng, LIN Xiaosong, LONG Qiuyue, LI Mengmei, HE Yong
    2020, 59(1):  105-113.  doi:10.13471/j.cnki.acta.snus.2020.01.013
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    Kmeans model and ARMA model was applied to classify 12 369 runoff river reaches in Wushan County, and study the change of hydrological parameters in time series, and probes into the evolution of rainfall runoff process by using the machine learning algorithm RF model. Combined with the GIS spatial visualization technology and the geographical environment of the study are, the flood disaster scope is predicted and the spatial distribution of flood disasters is analyzed based on the RF model. The results show that: 1) The RF model can effectively predict the importance of parameters in the rainfallrunoff process. When the rainfall intensities are 125 mm and 150-175 mm, the change rate of water level and velocity is the largest; when the rainfall intensity is 100-175 mm, the change rate of velocity is the most intense. 2) The ARMA model is used to predict the river gradient, flow and other hydrological parameters with the best regression. Among the predicted parameters of lower level rivers, the change rate of water level and flow velocity is the most obvious, and the flow quantity has no obvious change. Compared with the change rate of water level, the change rate of flow rate is more intense, and the change rate of flow rate and water level is mainly concentrated in the river with higher grade. 3) The machine learning algorithm can effectively predict the flood prone degree in the study area. When characterizing the hydrological parameters of the study area, the change of water level is mainly concentrated in the northwest and the south central part, and the change rate of water level in the northeast and the south central part is significant. It is predicted that the water level in some areas can rise to 20 m in extremely dangerous condition.

    Identification of specific DNA markers for Hirudo in the Naoxintong capsule
    2020, 59(1):  114-124.  doi:10.13471/j.cnki.jsysusse.2020.01.014
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    To identify the genuine species of Hirudo (Whitmania pigra,Hirudo nipponica), DNA molecular method was established. Based on mitochondrial cytochrome c oxidase subunit Ⅰ(COⅠ) gene, speciesspecific primers were designed for W. pigra and H. nipponica, respectively. Using three species-specific primers, PCR amplification was performed for the genuine species and the common adulterant Poecilobdella manillensis Lesson, as well as the Naoxintong capsules. Results showed that both primers WF1R2 and WF2R2 could specifically amplify the DNA of W. pigra with amplicons of around 200 bp, while the primers HF1R2 could specifically amplify the DNA of H. nipponica to generate amplicons of 142 bp. Besides, no amplification was obtained in the adulterant P. manillensis with above three pairs of primers. In addition, amplicons around 200 bp were obtained in Naoxintong capsules using primers WF1R2 or WF2R2, with the same sequences as W. pigra, which is the genuine species that the company used. These results indicated that without sequencing, the primers WF1R2 (or WF2R2) and HF1R2 could specifically amplify W. pigra and H. nipponica , respectively. Furthermore, the primers WF1R2 and WF2R2 could be applied to identify the genuine species in Naoxintong capsule. This DNA molecular identification method is simple, accurate, with high specificity and sensitivity, thus it could be used as a supplement to the conventional method for origin identification and further improve the quality control of Hirudo and the Hirudo in Naoxintong capsule

    Single nucleotide polymorphism of 21 Y-chromosomal loci in seven ethnic minorities of Zhuang-Dong Language in the Guizhou Province of China#br#
    ZHANG Xiuxiu, YU Yanqin, TIAN Wei, ZHANG Ting, WANG Chanjuan, SHAN Keren, HE Yan
    2020, 59(1):  125-132.  doi:10.13471/j.cnki.jsysusse.2020.01.015
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    The study aimed to determine single nucleotide polymorphism of 21Y-chromosomal loci in seven ethnic minorities, including Shui, Bouyei, Dong, Gelo, Zhuang, Maonan and Mulam, of Zhuang-Dong language in the Guizhou province of China, and explore differences in the polymorphism from other Language ethnics. The SNapShot method was used to detect the complex amplicons of the 21 Y-SNPs loci in 445 males from seven Guizhou Zhuang-Dong language ethnics. Frequencies of alleles, haplotypes, and haploid populations were calculated using a direct counting method. SPSS 24 was used for principal component analyses. The haplotype diversity values were 0.597 7, 0.945 6, 0.885 6, 0.886 9, 0.768 6, 0.358 7 and 0.707 8, respectively, in the seven ethnics. We performed principal component analyses based on the frequencies of haplogroups by comparing our data with those reported for other nine ethnic groups in China. The results showed that Zhuang-Dong Language and Hmong-Mien Language were clustered together. From the perspective of patrilineal genetics, the relationship of ZhuangDong Language to Hmong-Mien Language is relatively closer than those of other ethnics.

    Secondary metabolites from mangrove fungus  Aspergillus sp. and their biological activities
    ZHENG Yinglin, TONG Yichen , SUN Yingying , PANG Jiyan
    2020, 59(1):  133-143.  doi:10.13471/j.cnki.jsysusse.2020.01.016
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    Seventeen compounds (1-17) were isolated from the marine fungus Aspergillus sp. Their structures were determined by nuclear magnetic resonance (NMR) spectroscopy and mass spectrum (MS). Among them, compound 1 was first found as a naturally occurring compound and the known compounds 2-17 were confirmed via spectrum and literatures. The bioactivities of selected compounds were preliminarily evaluated. The compound 2 exhibited moderate inhibitory activities toward three cancer cells, RPMI8226, OCI-MY5, and MCF-7 cells, and compound 10 had significant protective effects on prolonging the survival life of C. elegans under heat stress. In addition, the compound 9 and 16 showed slight inhibition effects against Streptococcus pyogenes and meanwhile the compound 17 possessed slightly inhibitory activity on Streptococcus pneumoniae.

    Chiral enantiomer transition of Asp molecules catalyzed by hydroxyl ion and role of proton in water liquid phase environment#br#
    QIAO Chaoyang, YAN Hongyan, SUN Yongqing, LIU Yisi, LV Luyao, TONG Hua, WANG Zuocheng
    2020, 59(1):  144-153.  doi:10.13471/j.cnki.jsysusse.2020.01.017
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    Using the dispersion correction density functional ωB97X-D method, the MP2 method of perturbation theory and the SMD model method of selfconsistent reaction field, the title reaction of two stable conformations(Asp_1 and Asp_2) of Asp was investigated. The study of reaction channel and potential energy surface showed that the chiral enantiomer transition was realized by a series of Asp transition states of Hatom abstraction of hydroxyl ion(water clusters) and α-carbon, as well as the rotation of αcarboxy hydroxyl, β-carboxy hydroxyl, β-carboxyl and R-group. The intrinsic energy barrier of the rate-determining step of optical isomerization of Asp_1 and Asp_2 induced by α-H abstraction of hydroxyl ion and H abstraction of water molecule of αcarbon was about 27.0 kJ/mol, and the corresponding intrinsic energy barriers induced by H-atom abstraction of hydroxyl ion assisted with water molecule and H-atom abstraction of two water molecule of α-carbon were about 34.0 and 40.0 kJ/mol, respectively. It could accelerate the process of Asp chiral transition that proton attacks the α-carbon of intermediate carbon anion.