最新刊期
卷 60 ， 期 6 ， 2021
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An overview of the differences between shade and sun plants in photosynthetic structure and function
摘要：Shade and sun plants have different adaptation to light. In different light intensity and light quality growing environment， shade and sun plants have different photosynthetic structure and component content， which ultimately affect the photosynthetic function. Specific environmental requirements limit the wide cultivation of shade plants and sun plants and affect their yield. In this paper， the differences of photosynthetic structure and function between shade plants and sun plants were reviewed in order to provide reference for the transformation of shade plants and sun plants.关键词：shade plants;sun plants;photosynthesis;chloroplast- 5
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发布时间：2023-11-01
Invited review
- 摘要：In this paper， a parallel solving algorithm for the MHD equations based on the toroidal tokamak model is proposed， and the algorithm focuses on the numerical simulation of the nonideal MHD instability and its development process. In the proposed algorithm， we selected a fully-implicit scheme in the discretization， which has less limited time steps than the classic methods， and Newton-Krylov method for solving the nonlinear systems. Furthermore， according to the scalability test on the HPC platform， the solver based on the proposed algorithm has high parallel efficiency in the large-scale parallel computation， and the computational result has a good numerical consistency with the classic solvers. Therefore， the proposed algorithm has excellent adaptability for large-scale numerical simulation of MHD in the Tokamak plasma.关键词：magneto hydrodynamic;parallel computation;plasma simulation;magneto hydrodynamic instability
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发布时间：2023-11-01 - 摘要：In order to study the effect of EPS particle content on the permeability coefficient of mixed soil， the permeability coefficient of the mixed soil of Heyuan quartz sand， Fujian standard sand， and EPS particles were measured with a normal water head permeameter at six kinds of blending amounts： 0， 0.2%， 0.4%， 0.6%， 0.8% and 1% . To obtain a more accurate particle size distribution and average particle size of mixed soil， image processing methods and average particle size calculation methods are proposed. Based on the Coson-Carmen permeability formula， the relationship between the dimensionless parameters
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发布时间：2023-11-01 - 摘要：In order to reduce the harm and hidden danger of the horizontal swing of the deep-sea mining pipeline， this paper proposes a set of suppression scheme of the horizontal swing of the deep-sea mining pipeline. The executive parts of the scheme are mainly composed of nylon pull rope， hydraulic energy exchange component and fixed pulley component. Nylon pull rope can provide the tension to restrain the lateral swing and reduce the amplitude of the lateral swing； the hydraulic energy exchange component can consume the kinetic energy of the lateral swing and convert it into electrical energy； the fixed pulley component can adjust the force of the pull rope on the pipeline， so that it is more conducive to restrain the lateral swing of the pipeline. The experimental results show that the working principle of the scheme is feasible.关键词：pipeline lateral swing;swing suppression scheme;nylon cable;hydraulic energy exchange component;fixed pulley component
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发布时间：2023-11-01 - 摘要：In order to optimize the construction of the in-situ cast joints of the ultra-high performance concrete of the prefabricated bridge deck，the bending behavior of UHPC in-situ cast joints of prefabricated deck under bending moment is analyzed. The cohesive zone model is used to simulate the interface of in-situ cast joints. With experimental validation， the joint widths， reinforcement ratios and joint interface shapes are three types of parameters considered in finite element models. The result indicated that UHPC could be used as the casting material with a reduced joint width of 15 cm. The joint shape of cuneiform or diamond showed better flexural performance of the jointed panels than the shape of rectangular. The maximum reinforcement ratio of UHPC in-situ cast joint shouldn’t be greater than 2.6%.关键词：precast deck slab;ultra-high performance concrete;in-situ cast joints;U shape reinforcement;mechanical behavior
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发布时间：2023-11-01 - 摘要：Based on the Holmquist-Johnson-Cook（HJC） concrete damage constitutive model， the finite element model of the superstructure of the steel-concrete composite beam bridge was established by the nonlinear explicit dynamic analysis software ANSYS / LS-DYNA， and the stability of the calculation results was verified using the energy conservation principle. The dynamic response of the superstructure of the steel-concrete composite beam bridge under the impact of rockfall is studied from four aspects of rockfall speed， rockfall quality， contact area and collision position. The research shows， ① of all influencing factors， the change of rock fall speed has the most significant effect on the superstructure of the steel-concrete composite beam；② the damage to the bridge deck caused by rockfall is mainly local damage；③ rockfall kinetic energy， which combines the speed of rockfall and the quality of rockfall， can be used as an independent variable in the study of rockfall impacting a steel-concrete composite beam bridge；④ when the collision position is unchanged， the kinetic energy of rockfall is positively correlated with the volume of concrete loss.关键词：steel-concrete composite beam bridge;rockfall impact;dynamic response;finite element analysis
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发布时间：2023-11-01 - 摘要：To reasonably determine the number of data samples for Kriging model and to improve the predicting accuracy of Kriging model at minimum areas of objective function， this study proposes an adaptive Kriging model and applies it in the finite element model updating of bridge structures. The proposed method first estimates the initial number of data samples using central composite design， then Latin hypercube design is utilized to obtain the spatial distribution of data samples. The Kriging model is constructed based on the initial data samples set. Finally， the expected improvement （EI） criterion is employed to control the location of newly increased data samples， making them mainly locate at the minimum areas of objective function. The number of newly increased data samples are determined by convergence criterion. The predicting accuracy of standard Kriging model and adaptive Kriging model are compared by using test functions. The model updating of a pedestrian cable-stayed bridge is taken as an example， in which the updating results of Kriging model and adaptive Kriging model are compared. The results show that the accuracy indexes of Kriging model and adaptive Kriging model are almost the same under that the premise the total number of data samples is equal. However， the adaptive Kriging model can avoid the random distribution of data samples in design space， thus provide a higher predicting accuracy in minimum areas of the objective function and obtain better updating results.关键词：bridge engineering;adaptive Kriging model;model updating;expected improve criterion;surrogate model
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发布时间：2023-11-01 - 摘要：Due to the continuous development of static reactive compensation device， the coordinated control between different devices becomes more and more important. In this paper， on the basis of the TCR+FC model，a TSC branch as reactive power reserve is added to make up TCR+TSC+FC type SVC. Depending on the relationship between the trigger angles of TCR and the reactive power demand of the system， a TSC control system is designed based on the average of TCR three-phase thyristor trigger angles. Meanwhile， in order to ensure the fast and accurate switching of the TSC capacitors， the triggering control mode of enabling thyristors with positive and negative phase at the same time is also designed when the voltage at both ends of the thyristor crosses zero. The simulation results of PSCAD with an engineering example show that the design scheme is correct and feasible.关键词：SVC;coordination control;average of trigger angles;fast and accurate switching
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发布时间：2023-11-01 - 摘要：CFRP is widely used in the field of structural reinforcement due to its superior mechanical properties. The reinforcing effect on steel structures is affected mainly by the bonding behavior of interface between CFRP and steel. In this paper， the specimens of CFRP-Q345B steel plates and CFRP-X100 steel plates under double shear test are used to investigate the bonding behavior of interface. And the surface strain of CFRP is simultaneously measured by DIC measuring system and strain gauges. The failure characteristics and mechanical behavior of CFRP- steel interface are studied， and the effects of adhesive layer’s thickness and steel plate material on interfacial shear performance are discussed. The test results show that： when the thickness of adhesive layer is 0.1 mm and 0.5 mm， the failure modes of interface are steel plate-adhesive layer interface failure and cohesive failure of adhesive layer respectively； the ultimate bearing capacity is affected by the steel material， and the bonding force between the adhesive and Q345B steel plate is greater than that between the adhesive and X100 steel plate； the interfacial shear stress distribution measured by DIC measuring system can reflect the mechanical behavior of bonding interface more comprehensively and intuitively.关键词：CFRP;double shear test;steel plate;DIC;interfacial bonding performance
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发布时间：2023-11-01 - 摘要：In recent years， the study of historical disasters from the perspective of disaster geography focuses on spatiotemporal evolution and series analysis， and the recovery of historical clustering disasters needs attention. The clustering disasters such as drought， locust plagues， famine and epidemic disaster occurred during the 8th to 16th Chongzhen years （1635-1643） in the late Ming Dynasty were relatively rare in terms of duration， scope， and level. By sorting out the historical documents and constructing the data set， this paper takes drought and locust plagues as the line to recover the spatiotemporal evolution and correlation between clustering disasters， and clarify the climatic background of this period. The results show that： （1） The development of disasters presented a single peak type of “fast increasing followed by slow decreasing” trend， but the peak years were different. Drought， locust plagues and famine were severely affected during 1638-1641. The epidemic had a lag period and reached its peak in 1641. （2） The drought was widely distributed in the eastern monsoon region of China， and the Huang-Huai-Hai Basin and the lower reaches of the Yangtze River were the core affected areas. The outbreak of locust plagues was relatively concentrated along the lower reaches of the Yellow River and around the lakes， which reflected the obvious “water approaching characteristic”. （3） Compared with drought， locust plagues showed significant spatial correlation and temporal succession， and famine and epidemic disaster presented a lag. Drought significantly promoted the outbreak intensity of locust plagues. （4） During the Little Ice Age， continuous extreme cold and dry climate aggravated the outbreak of locust plagues， which may be related to large-scale circulation or other external environment changes， and the pattern of the disaster chain multiplied the intensity of the situation.关键词：clustering disasters;locust plagues;spatiotemporal process;climate background;late Ming dynasty（1635-1643）
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发布时间：2023-11-01 - 摘要：In order to study the seasonal variation of soil ammonium nitrogen and nitrate nitrogen （
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发布时间：2023-11-01 - 摘要：To investigate the Ebinur lake wetland soil physical properties under salt crusts and their interactions， we selected representative samples of 30 sites from different areas in wetland and with different salt crust thickness， on the depth of 0-20 cm， 20-40 cm，and 40-60 cm， analyzed the physical properties of soil， including porosity， particle size， and water content by combining field investigation and laboratory tests， and discussed the influences of properties on salt crust thickness. The results show that： 1） The grain size of soil covered by salt crust is mainly in the range of 1.00-0.05 mm during the declining and the growing periods， while at the mature stage it is mainly in the range of 0.01-0.001 mm. The bulk density of soil is ranked from the highest one of the salt crust in the growing period （1.81 g/cm3）， to that of the mature period （1.58 g/cm3） and to the lowest one of that in the declining period （1.34 g/cm3）. The soil porosity decreases gradually from the declining period （50.8%）， mature period （40.7%） to the growing period （32.6%）. Soil moisture content from high to low is in the order of growing period （32.5 g/kg）， mature period （21.7 g/kg）， and the declining period （16.2 g/kg）. Soil saturated water content and soil moisture content are in the order of the declining period， mature period， and the growing period from high to low. 2） Salt crust thickness is significantly positively correlated with both capillary porosity and soil particle size in the range of 0.05-1 mm for soil in the depth of 0~20cm soil （P<0.01）， while negatively correlated with soil bulk density （P<0.05）. The correlation between salt crust thickness and soil physical properties gradually decreases with the increase of depth. 3） The factors influencing salt crust thickness mainly include the capillary porosity as the first principal component （78.1%） and the soil particle size as the second principal component （16.5%）. The increase of porosity can promote the formation and accumulation of salt crust， and make the salt crust thicker， while the increase of grains in the size of 0.001 to 0.01 mm can inhibit the formation and accumulation of salt crust， and make salt crust thinner. Overall， salt crust changes the physical characteristics of soil （water content， porosity， and grain size）； on the other hand， the physical properties of soil affect the thickness of salt crust.关键词：Ebinur Lake wetland;soil salt crust;physical properties;influencing factors
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发布时间：2023-11-01 - 摘要：To investigate the impact of climate change on agricultural production in the Aksu river basin, climate data of daily air temperature, hours of sunshine, and some of the agriculture data from Aksu and Keping weather stations during 1967-2019 were analyzed for month, season and year by using methods of the single linear regression, accumulative anomaly, Mann-Kendall (M-K) trend analysis, and mutation test. The results show that: (1) The temperature in the study area increased from 1967 to 2019, and the warming tendency rate of Aksu and Keping stations were 0.515 and 0.023 ℃/10a, respectively; the sunshine hours of Aksu and Keping stations showed a decreasing trend, and the trend rates were 3.806 and -32.916 h/10a, respectively. The temperature of Aksu station had a sudden change in 1997, and the sunshine hours of Keping station had a sudden change in 1990. (2) From 1967 to 2019, the average accumulated temperature ≥10 ℃ in the study area was 4 240 ℃/d, and the average duration was 210.6 d. After the mutation occurred in 1997, the average value of accumulated temperature ≥10 ℃ increased from 4 143 ℃/d to 4 369 ℃/d from 1967 to 1996, and the duration of days increased from 209 d to 214.9 d, which created a good growth environment for crops. (3) In recent 40 years, the amount of chemical fertilizer per unit area in the study area increased from 63.8 kg/hm2 in 1978 to 1 369 kg/hm2 in 2018, an increase of 1 304 kg/hm2; the cotton yield per unit area increased from 288 kg/hm2 in 1967 to 1 218 kg/ hm2 in 2018, with an increase of 930.2 kg/hm2 and a tendency rate of 262 kg/10a. The sowing date of cotton was advanced by 9 d, while the stopping growth period was delayed by 3 d, thus the growth period was extended by 6 d. (4) With the change of climate in the research area and the continuous development of technology, the warming of temperature increases the yield and quality, which is conducive to the development of agricultural production in the Aksu river basin.关键词：climate;change characteristics;agricultural production;Aksu river basin
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发布时间：2023-11-01 - 摘要：In this study， we focused on the pollen germination of Polygonatum cyrtonema Hua in homogeneous garden. We examined the flowering phenology， floral visitors as pollinators， and pollination biology. The single factor and orthogonal test were designed to study the effect of different culture medium （sucrose， boric acid and calcium chloride） on pollen germination in vitro， and I2-KI， MTT and TTC methods were applied to determine the pollen viability， the stigma receptivity at different times during flowering were estimated and the fruit production was recorded. Results showed that： ① Flowering began in late April， peaked toward the middle of May， and finished in the begin of June， the flowering lifespan of an individual， inflorescence and intact flower was 8~13 d， 3~7 d and 1~3 d respectively. The flowering amplitude of inflorescence showed a multi-peak curve， and the synchronous index is 0.81±0.12. ② The best medium for pollen germination was： sucrose 150.00 g/L + H3BO3 200.00 mg/L+CaCl2 250.00 mg/L. ③ TTC was the most effective method to determine pollen viability of P. cyrtonema．④ The pollen was active at the first 2 days before flowering， reached highest at the second or third day of flowering， and gradually decreased with anther dehiscenced and pollen released. After withering， no pollen viability was detected. ⑤ The stigma had receptivity at the first 2 days before flowering， reached highest at the second or third day of flowering， and was still receptive at the fourth to fifth day of flowering. ⑥ The pollinators of P. cyrtonema were Apis cerana， Episyrphus balteatus and Bombus latreille， and Apis cerana was the major pollinators. ⑦ The average fruit production of P. cyrtonema was 46.35%.关键词：Polygonatum cyrtonema;flowering phenology;pollen germination;stigma receptivity;pollinators;Apis cerana
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发布时间：2023-11-01 - 摘要：3-[2-(5-Bromo-thienyl)]-1-phenyl-2-propenone (BTPPO) was synthesized from acetophenone and 5-bromothiophene-2-carbaldehyde. The spectrometric and molecular docking were employed to investigate the binding mechanism of BTPPO to bovine serum albumin (BSA）, and the effects of metal ions (Cu2+, Co2+, Pb2+, Ag+, Hg2+, Cd2+) on the BTPPO-BSA binding system were also discussed. The spectrometric experiment results showed that the binding reaction of BTPPO to BSA was based on the static fluorescence-quenching process with hydrophobic and electrostatic forces, and the binding constant (Ka) was about 104. Based on the Förster theory, the binding distance (r) between BTPPO and BSA was less than 7 nm. Comparing the quenching of protein fluorescence excited at 280 nm and 295 nm, it was shown that the primary BTPPO binding site was located in the sub-domain ⅡA (siteⅠ) of BSA. The presence of metal ions (except Pb2+) may influence the BTPPO efficacy. The molecule docking results illustrated that BTPPO can bind with the sub-domain ⅡA of BSA in which hydrophobic and polar interactions are the key acting force.关键词：3-[2-(5-Bromo-thienyl)]-1-phenyl-2-propenone （BTPPO）;bovine serum albumin（BSA）;binding mechanism;fluorescence;molecule docking
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发布时间：2023-11-01 - 摘要：Ganpu Tea is black tea， and made of Citri Reticulatae Pericarpium and Pu'er Tea. It not only has a unique flavor and taste， but also has the effects of Pericarpium Citri Reticulatae and Pu'er Tea. It is a superior healthful product. Tea， as the main drinking in the daily life，was mainly brewed with water. In order to comprehensively analyzed the water-soluble constituents of peel of Ganpu Tea （PGT）， Citrus reticulata cv. Chachiensis （CRC）， and Citrus tachibana (CT)， the water extracts of PGT， CRC， and CT were detected by Ultra High Performance Liquid Chromatography combined with four pole time of flight mass spectrometry （UPLC- Q-TOF-MS）. 47， 72 and 56 chemical components were identified from PGT， CRC and CT， respectively， including flavonoids （44， 63， 50）， limonoids （1， 4， 4）， alkaloids （1， 2， 1）， coumarins （2 only in CRC） and cyclic peptide （each 1）. All results together enriched the chemical constituents of Ganpu Tea and Citri Reticulatae Pericarpium， and provided effective chemical information to further study the medicinal value and health care effect of Ganpu Tea.关键词：Ganpu Tea;peel of Citrus reticulata cv. Chachiensis;peel of Citrus tachibana;component analysis;UPLC-Q-TOF-MS
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发布时间：2023-11-01 - 摘要：In this paper， the rotor blade is simplified to rotating beam for which the proposed fast sparse regularization approach is applied to realize the damage detection. The damage detection can be formulated as a nonlinear least squares problem that finds the damage parameters to minimize the residuals between the calculated modal data and the measured modal data. Damage detection is a typical inverse problem which is usually ill-pose， i.e.， the identification is sensitive to the noise. To overcome such ill-posedness and quickly deal with the inverse problem， the fast sparse regularization approach is proposed， which transforms the sparse regularization into a frictional-model，whose regularization parameter is the static friction force. Numerical example demonstrates the accuracy and efficiency of the proposed approach for it enable to select the suitable regularization parameter quickly.关键词：rotating beam;damage detection;sensitivity analysis;sparse regularization;regularization parameter
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发布时间：2023-11-01 - 摘要：The necrotic hyperbolic tumor growth model with Robin free boundary is studied.The model contains an elliptic equation describing the diffusion of nutrient in the tumor，an ordinary differential equation describing tumor radius，and three nonlinear first-order hyperbolic partial differential equations describing the evolution of proliferating cells，quiescent cells and dead cells，respectively.By applying the characteristic theory of hyperbolic equations and the Banach fixed point theorem，the existence and uniqueness of the global solution of the model are proved.It is proven that
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发布时间：2023-11-01 - 摘要：In order to solve the problem that particle swarm optimization is easy to be trapped in local optimum， low convergence precision and slow convergence speed， a hybrid hierarchical autonomous learning quantum particle swarm optimization （HHQPSO） is proposed. Firstly， the population is dynamically divided into three layers according to the fitness value of particles and the number of iterations. Since the particles of upper and lower layers are less distributed， local learning model and global learning model are respectively used to increase the diversity of particles. While the particles of middle layer are more distributed， the hybrid adaptive quantum learning model is adopted. Secondly， an improved differential strategy is proposed to update the random positions of particles in the hybrid quantum model， and the Levy flight strategy is introduced to improve the convergence accuracy and speed of the algorithm. Finally， six improved particle swarm optimization algorithms are compared on 9 typical test functions. Experimental results show that the HHQPSO algorithm has obvious advantages in convergence accuracy， speed and stability， especially suitable for multi-peak search function optimization.关键词：quantum particle swarm;differential strategy;Levy flight strategy;autonomous learning
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发布时间：2023-11-01 - 摘要：The weak oscillation of solutions of third-order Emden-Fowler differential equations with unbounded neutral coefficients is studied. By introducing parameter function and the generalized Riccati transformations ， using integral averaging technique and some necessary technique， some new oscillation criteria which ensure that all solutions of the studied equation weakly oscillates are obtained. The results generalize and perfect a number of related results in the literature recently.关键词：third-order;Emden-Fowler differential equation;weak oscillation;nonoscillatory
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发布时间：2023-11-01
Research articles
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